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CROSS-REFERENCE TO RELATED APPLICATION
This application is a utility conversion of U.S. Provisional Patent Application Ser. No. 61/059,682, filed Jun. 6, 2008, for “PLUG ASSEMBLY WITH PLUG HEAD ATTACHMENT.”
FIELD OF THE INVENTION
This invention relates to industrial valves. More specifically, this invention relates to devices for attaching valve plug heads to valve plug stems.
BACKGROUND OF THE INVENTION
Valves and valve plugs are well known in the art. Typically, valve plug heads are positioned within the valve to control the volume of flow passing through the valve. By modifying the position of the plug head relative to the valve seat, control of the flow volume is achieved, thus allowing diversion and restriction of fluid flow. Plug heads are subjected to fluid forces, chemical attack, thermal stresses, impact from particulates and debris, as well as the forces used to attach it to the plug stem and seat loading forces that can occur when the plug head comes into contact with the valve seat. The valve head is typically attached to a plug stem, which in turn is connected to an actuating device. This actuating device is controlled to move the plug stem, which acts to change the position of the plug head to control the flow passing through the valve.
The plug stem is subjected to axial forces as the actuator moves it, mounting forces relating to the actuator attachment, and the long cylindrical section is subjected to bending forces. The plug head and the plug stem perform distinctly different purposes and are subjected to very different forces. The plug head, sitting in the middle of the flow stream, diverts and/or restricts flow, and is subjected to fluid and seat loading forces and to forces related to attaching the plug head to the plug stem. In contrast, the plug stem is moved by an actuating device to provide a sealing surface and is subject to axial and bending forces. In industrial, high volume/flow rate valves, the forces placed on plug stems and plug heads are typically significant contributors to valve failure.
Traditionally, valve plug heads are either composed of one monolithic material or make use of more than one material. Plug heads employing more than one type of material have particular advantages, in particular, better erosion and corrosion resistance, improved shock absorption, working life, and thermal expansion qualities. However, the use of a plurality of material types has been limited by the ability to effectively join the materials together economically and without creating stress points that limit the life of the plug head.
The most common methods of fixing dissimilar materials together in a valve plug are taper fitting or interference fitting, both of which employ a retaining ring that is fixed around the plug head. Taper fittings have been shown typically to subject the plug head to undesirable stresses, contribute to thermal expansion problems, and are difficult to repair. The typical taper fitting design requires a mating of two conical surfaces, one on the plug head, and the other on the retaining ring. Since neither the plug head nor the retaining ring can be manufactured with ideal cone shapes, the plug and seat may not mate perfectly. As such, loading between the two mated structures may not be uniform. Additionally, the force of the retaining ring on the plug head is exerted close to the edge of the plug head and is generally perpendicular to the angle of the conical surface. The location and angle of the force can introduce undesirable tensile forces into the portion of the plug head that bears the force. Often the desired plug head material may demonstrate weak tensile strength, thus introducing additional tensile forces that can either limit the selection of plug head materials or that can cause breaking of the edge of the plug head, separating the plug head from the plug stem and causing valve failure. Also, as the retaining ring wears away through normal corrosion and erosion, the shape of the contact area can change, typically moving closer to the edge of the plug head. This contact area change tends to concentrate forces on the edge of the plug head and increases the likelihood that the edge of the plug head will fracture, thereby causing the plug head to separate from the plug stem. The stresses induced with the taper fit are difficult to quantify and, therefore, can detract from a valve plug's performance. Variables in the welding process, such as weld shrinkage, inter-pass temperature, amperage of weld, inert gas environment, and the amount of initial burn-in, can change the amount of stress in the plug head.
As noted above, typical prior taper fit designs attach the taper fit ring to the plug stem via welding. This approach results in the retaining ring and the plug stem becoming permanently joined into one component. If the plug head wears away or breaks and the plug stem is still usable, the typical taper fit design does not lend itself to achieving the proper concentricity between the plug head and the plug stem after the plug head has been replaced. When a taper fit valve plug is repaired, the plug stem has already been machined, so it is not possible to make adjustments in the plug stem to ensure concentricity with the plug head. If the plug head is misaligned, adjustments cannot be made without cutting the taper fit ring off. For at least these reasons, taper fit valve plugs are usually discarded (as opposed to being repaired) when the plug head has broken or worn away. During assembly, the taper fit ring is typically fit tightly around the ceramic plug and the taper fit ring is welded to the plug stem. At elevated operating temperatures, the taper fit ring increases in size more than the plug head, and the plug head becomes somewhat loose in the taper fit ring, which thereby leads to early failure of the fit in operating conditions.
Interference fittings typically require a bulkier retaining ring, contributing to the load on the plug head. Interference fittings also require more complex procedures to replace plug heads and are generally limited in their service temperature ranges. An interference fit achieves more uniform loading of the plug head than does the taper fit. However, the typical interference fit uses a one-piece retaining ring that not only holds the plug head but also attaches the plug head/retaining ring assembly to the plug stem. The interference fit also must have sufficient material to allow for the wear due to erosion and corrosion without causing the plug head to separate from the plug stem. These requirements result in a bulkier retaining ring than is required to hold the plug head in place, which contributes to an additional load on the plug head. This additional load introduces tensile stresses, which tend to contribute to plug head breaking and separation, which can result in valve failure.
Even with interference fit designs, the task of replacing the plug head is quite complex. To replace the plug head, the interference fit ring must be cut, separating the plug head and ring assembly from the plug stem. This process is usually performed on a lathe or mill. If the ring is to be used again, it is necessary to separate the ring from the plug head. Certain combinations of plug head and interference fit ring materials can be separated by heating the assembly in an industrial oven. If the coefficient of thermal expansion of the retaining ring is sufficiently higher than the plug head, the retaining ring will expand more quickly and the interference fit will be negated as a space forms between the two surfaces. This approach is somewhat destructive and requires that the interference-fit ring be carefully checked before reuse. Also, this heating method only works with certain combinations of materials. Moreover, even when it may work, the plug head replacement process requires specialized manufacturing facilities that are generally unavailable to users in remote locations. Therefore, replacing plug heads for valve plugs is not a typical industry practice for certain combinations of materials or user locations.
Another problem with interference fittings is that service temperature ranges are limited because of differential thermal expansion between the plug head and ring materials. The amount of interference between the plug head and the ring is directly related to the amount of stress in a plug head. The amount of interference at ambient temperature becomes a concern when it places large amounts of stress on the plug head. Thus, when the valve plug is installed and is warming to operating temperature, the plug head is more highly stressed and is more vulnerable to failure. It has also been observed that because of these stresses, certain valve plugs, head and rings, could not be used because the ambient temperatures, or below ambient storage temperatures, could cause the plug head to fail before they could placed into service.
Also, both taper fittings and interference fittings suffer from the impracticalities of stress relieving heat affected weld zones with heat treatments. For highly corrosive fluid applications and with certain materials, it is important to stress relieve heat affected weld zones with heat treatments. With both prior existing taper fit and interference fit designs, this has not been considered practical because stress-relieving typically is performed at temperatures high enough to allow the plug head to be excessively loose in the ring, and it is not possible to assure that the plug head would return to its proper position upon cooling. Therefore, even though heat treatments might be beneficial, they have generally been avoided.
In view of the foregoing shortcomings, it would be desirable to provide a valve plug design that uses a clamping system to attach the valve plug head to its valve plug stem, and to thereby provide a means of assembling and replacing worn plug heads in the field, while allowing use of different materials for the plug head and the plug stem, where the different materials are selected specifically to address the different function of the plug head and the plug stem. This type of plug design is particularly desirable for use in flow streams that are erosive or corrosive in nature, because plug heads in these kinds of streams typically suffer material loss due to the erosion and/or corrosion and require regular replacement. Often the plug head wears out before other valve components. Therefore, minimizing the occurrences when the plug head fails and must be replaced is very desirable in improving the life cycle and efficiency of the valve.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a side view of a plug head and a plug stem according to an embodiment of the present invention;
FIG. 2 illustrates an enlarged view of clamps, plug stem, and plug head according to an embodiment of the invention;
FIG. 3 illustrates an enlarged side view of a plug head and a plug stem according to an embodiment of the present invention;
FIG. 4 illustrates a representative system of a valve plug according to an embodiment of the present invention in a valve assembly; and
FIG. 5 illustrates a section view of a valve plug having a plug head mounted to plug stem base of a plug stem according to an embodiment of the invention.
SUMMARY OF THE INVENTION
One embodiment of the present invention includes attaching a ceramic (or other sacrificial material) plug head to a plug stem. The embodiment uses two retainer half rings (clamps) and two or more bolts/nuts to hold the head onto the plug stem. In this fashion, replacement of the plug head can be easily and quickly accomplished in the field. The two clamps are configured such that a gap is left therebetween on both sides. The bolts/nuts are sacrificial bolts which are inexpensive. Rather than undo the bolting, these bolts can easily be cut off and thrown away. The bolting can then be replaced and a new plug head installed, reusing all of the major components. Other embodiments may use three or more retainer rings (clamps) to hold the plug head onto the plug stem. It is understood that all modifications and embodiments discussed herein may also be adapted to include three or more retainer rings (clamps).
When ceramic plugs are used, it is common to replace field worn plug heads with new ones. These applications often involve scaling, erosion and high temperatures. This design has several advantages over current designs. This design is easier to work on in the field and the factory. Assembly of this design is simpler than previous designs. Some old designs even required shrink fitting and welding of the parts to hold them together. This precluded field assembly of plugs. This design allows simple field assembly. Assembly in the factory is also simplified. The gap left between the two clamps is important as many of the services which require erosion-resistant plug heads have solids in the fluid stream. Solids tend to build up on parts. When threaded parts are used it can make undoing threads impractical or impossible, which would make reusing the stem impossible.
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention includes a plug assembly that includes a plug head made of a sacrificial material that is attached to a plug stem with two retainer half rings. The plug assemblies of this invention are adapted for use in industries such as, for example, mining, chemical processing, and oil and gas refining, where the flow is abrasive and/or corrosive and which may contain substantial quantities of sediment, debris or scale. Valves in certain erosive and/or corrosive flow streams encounter a significant amount of sediment, debris or scale which comes through the pipe line. This invention provides plug heads and stems being made of dissimilar materials having different properties that optimize the performance of the plug head, the plug stem and the fastening band. Also, this invention is adapted to ease the process of repair and replacement of valve plug components, permitting maintenance to be accomplished in the field without requiring specialized manufacturing equipment or highly skilled personnel. The invention is also adapted to provide a tight shutoff by permitting improved alignment of the plug head and seat ring.
In a particular embodiment of the invention, the plug assembly allows the plug head to shift from side to side. When control valves are produced, there is always a certain amount of variation in the parts and assembly. However, in order to provide tight shutoff, the plug head and seat ring must line up perfectly. Since manufacturers cannot make the parts perfectly, plug assemblies need a certain amount of adjustability.
In most valves, the seat ring can shift a little from side to side to allow the seat ring to center up on the plug. This is typically done by keeping the bonnet a little loose while stroking the plug into the seat repeatedly. Once the seat ring has moved to center itself, the bonnet is then tightened, locking the seat into place. This process is described in detail in the Mark One User Manual (VLENIM0001) steps 7.9 to 7.9.2, the contents of which are incorporated by reference herein. Some valve designs allow the bonnet to shift a little from side to side instead of shifting the seat ring, as when a screwed in seat is used. In the case of survivor, the seat ring is pinched between the valve outlet and the valve body. Performing a seat centering procedure is more difficult and is described in the Survivor User Manual (VLENIM0036), the contents of which are incorporated by reference herein.
Because this process is so difficult to perform, one particular embodiment of the present assembly is configured to allow the plug head to float (instead of the bonnet or seat ring). This particular embodiment allows the plug head to move slightly from side to side. This action allows the plug head to find a natural center on the seat ring, providing the best shutoff possible.
Referring to FIGS. 1 and 3 , a particular embodiment of the plug head and plug stem of the present invention is illustrated. A valve plug 100 is shown having a plug head 101 held in a plug stem base 103 which in turn is mounted on the plug stem 102 . As shown in FIG. 2 , the plug head 101 includes a base portion with a beveled edge 110 . A distal portion of the plug stem 102 includes a beveled edge 112 . The plug head 101 is held in the plug stem base 103 by two clamps (half rings) 104 which provide an interference fit between the plug head 101 and the plug stem 102 . The two clamps 104 are fitted over the plug head 101 and the plug stem base 103 and are tightly held in place by four bolts 120 . In a particular embodiment of the invention, the bolts 120 are fixed in place by nuts 107 a , 107 b . Alternatively, two clamps can be held in place by pins, screws, welds, brazing, clamps or the equivalent. Additionally, the clamps 104 can include a hinge mechanism or tongue-and-groove mechanism to hold the two clamps 104 together on one end, while relying on two bolts 120 to secure the two clamps 104 together at an opposing end. The two clamps 104 can provide shock absorbing capabilities and stress relief to the plug head 101 during use.
The preferred plug head 101 can be composed of structural ceramics because of its resistance to wear and degradation in flow streams that are erosive (having fine-grit particles) and corrosive (due to the chemical composition of the flow). Structural ceramics are a class of materials that includes, but is not limited to silicon carbide, silicon nitride, aluminum oxide, zirconium oxide, tungsten carbide, whisker-reinforced blends of ceramics, two-phase ceramics, and the like. Alternative materials which may be substituted for structural ceramics for the plug head 101 , include, but are not necessarily limited to, cermets, which are compounds that are combinations of ceramics and metals, cast iron, silicon iron, white iron, heat treated martensitic steels (such as 440 or 416 grade steel), CrCoFe alloys (such as STELLITE® M alloy 3, STELLITE® alloy 6, and STELLITE® 12), or other metals. Alternative materials with similar properties can be substituted without departing from the concept of this invention.
The plug stem 102 , plug stem base 103 and clamps 104 can be composed of materials selected for ease of machining to a smooth surface, having good tensile strength, reasonable ductility and cost effectiveness. Included within this class of materials are titanium and its alloys, zirconium and its alloys, niobium and its alloys, titanium-niobium alloys, alloy steels, carbon steels,—iron-based superalloys, stainless steels, nickel and its alloys,—nickel-based superalloys, copper-based alloys, cobalt alloys,—cobalt-based superalloys, aluminum and its alloys, magnesium alloys, tantalum, and the like. Alternative materials with similar properties can be substituted without departing from the concept of this invention.
The clamps 104 can be composed of metal alloys, including but not limited to titanium and its alloys, zirconium and its alloys, niobium and its alloys, titanium-niobium allows, alloy steels, carbon steels,—iron-based superalloys, stainless steels, nickel and its alloys, —nickel-based superalloys, copper-based alloys, cobalt alloys,—cobalt-based superalloys, aluminum and its alloys, magnesium alloys, tantalum and metals of similar properties. Alternative materials with similar properties can be substituted without departing from the concept of this invention.
FIG. 4 shows a representative system of a valve plug 100 of this invention in a valve assembly 300 . The valve plug 100 is shown in a substantially closed position with the plug head 101 closing a first flow path 303 from the valve chamber 301 and a second flow path 302 . The plug stem 102 is shown connected to the actuator 304 and sealed with the shaft 305 in close, preferably fluid tight proximity, with valve stem support (or shaft support) packing (not shown). FIG. 4 shows an embodiment of the valve plug 100 in its working environment in a typical valve assembly 300 . The actuator 304 functions to position the valve plug 100 either in the shown closed position or retracted to permit fluid flow from the first flow path 303 to the second flow path 302 . Alternatively, the flow can, as is common in some valves, flow in the opposite direction.
FIG. 5 shows a section view of an alternative embodiment of a valve plug 200 having a plug head 201 mounted to plug stem base 203 of a plug stem 202 , this embodiment having additional compliance structure provided. In contrast to the embodiment described in FIG. 1 , the present embodiment includes a plug stem base 203 having a base portion with a non-beveled end or edge 214 . Additionally, the plug stem base 203 can have a smaller diameter than the diameter of the plug head 201 . Plug head 201 can include a base portion with a beveled edge 210 . This design permits the plug head 201 and clamps 204 to move and adjust relative to the plug stem 202 , which allows the plug head 201 to self center when in use in a valve assembly, such as the valve assembly 300 of FIG. 4 . An embodiment of the valve plug 200 can include washers or springs 220 within or adjacent to plug stem base 203 to provide cushioning and separation between the plug stem base 203 and the plug head 201 . Representative spacers include, but are not limited to Bellville washers and spring mechanisms.
Alternative embodiments of the invention include spacers (not shown) on the bolt sections between sections of the clamps 204 that are adjacent to plug head 201 in order to prevent deflection of the clamps 204 .
The described embodiments, including the various materials, specific components, and dimensions, are to be considered in all respects only as illustrative and not as restrictive. The invention should not be considered limited to the particular preferred and alternative embodiments, rather the scope of the invention is indicated by the appended claims. All changes, modifications and alternatives which come within the meaning and range of equivalency of the claims are to be embraced as within their scope. | A plug assembly includes a plug stem having a plug stem base, a plug head, and a fastening mechanism for fastening the plug stem base to the plug head, the fastening mechanism comprising at least two retainer clamps that surround and provide an interference fit between the plug stem base and the plug head. A method of replacing or attaching a plug head to a plug stem includes providing a plug stem having a plug stem base, providing a plug head, providing a fastening mechanism comprising at least two retainer clamps, and coupling the fastening mechanism around the plug stem base and the plug head to provide an interference fit between the plug stem base and the plug head. |
This is a division of application Ser. No. 595,176, filed July 11, 1975, now U.S. Pat. No. 4,046,551.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to organic digesters and more particularly to an improved organic digester apparatus and to an improved method of producing liquid fertilizer and methane gas from organic materials.
2. Description of the Prior Art
The method of manufacturing natural fertilizer and methane gas from organic material by anaerobic digestion is well-known and products sold from this process include a granular fertilizer which is sold under the name Milorganite. The typical method generally includes depositing organic material into a closed container and maintaining the temperature of the organic material at a temperature range of 90 degrees to 105 degrees Fahrenheit for a period of 42 to 60 days.
The typical apparatus has generally included a spherically shaped digester tank and removable roof member. The types of apparatus and methods previously used include the batch type digester in which a quantity of organic material is placed in the digester and retained in the digester until completion of the digesting process, and the displacement type digester in which organic material is continuously, or continually, deposited in the digester, and liquid fertilizer is continuously, or continually, removed from the digester.
The problem which is inherent with the batch type digester is that organic material can be deposited in the digester only after completion of the digesting cycle and the removal of completed fertilizer from the digester. The problem which is inherent with the displacement type digester is that incompletely digested material is mixed with the completely digested organic material which has been transformed into liquid fertilizer; so that, when the liquid fertilizer is removed from the displacement type digester, rather than being pure fertilizer, it is contaminated with incompletely digested organic material.
SUMMARY OF THE INVENTION
In accordance with the broader aspects of this invention, there is provided an organic digester apparatus which includes a digester tank and a removable roof member. The digester tank is of generally cylindrical shape and includes a conical bottom member. The digester tank is also provided with a circumferential sealing well which is displaced radially outward from the digester tank. The removable roof member includes a circumferential sealing skirt depending from the lower surface of the roof member and extending downward into the sealing well. A liquid in the sealing well provides a gas-tight seal between the inside of the digester tank, which contains methane gas, and the outside atmosphere.
The apparatus includes control means for controlling the volume of gas within the digester tank so that the roof member is floated by gas pressure above the digester tank within predetermined, or adjustably predetermined, upper and lower limits. An electric motor drive is provided between the roof member and the digester tank to controllably rotate the roof member, very small power being required to rotate the roof member since it is floating on the methane gas.
An observation capsule is provided in the roof member and depends therefrom downward into the digester tank. The observation capsule is provided with windows for observing the inside of the digester walls, with a source of water and directable nozzle for washing the inside of the digester walls, and with an electrical switch for selectively controlling the rotation of the roof member as the walls of the digester are washed and inspected.
In a preferred embodiment some of the apparatus includes four digesters, the four digesters being a collecting digester, a first stage digester, a second stage digester, and a final stage digester. The apparatus further includes liquid and gas handling systems.
The liquid handling system includes a slurry pump, valves, and conduits for depositing, transferring, and removing liquid materials. The liquid handling system further includes a meter for measuring the quantity of liquid fertilizer removed from the final stage digester.
The gas handling system includes a control device for maintaining the gas volume in the digester tank at a volume which maintains the roof member between upper and lower predetermined limits, a gas meter for measuring the volume of gas removed from each of the digester tanks, a storage tank for storing the gas at an increased pressure level, and a compressor which is driven by a natural gas type of internal combustion engine for compressing the gas into the storage tank.
The method includes periodically depositing organic material into the collecting digester, transferring the organic material from the collecting digester to the first stage digester, transferring the organic material from the first stage digester to the second stage digester, transferring the organic material from the second stage digester to the final stage digester, holding the organic material for at least seven days in the last three mentioned digesters, removing liquid fertilizer from the final stage digester, and removing methane gas from all of the aforesaid digesters.
It is a first object of this invention to provide a digester tank for organic materials which includes a liquid seal between the digester tank and the roof member.
It is a second object of this invention to provide means for rotating the roof member of an organic digester apparatus.
It is a third object of this invention to provide control means for controlling the volume of methane gas within an organic digester apparatus to maintain the roof member of the digester apparatus in a floating relationship above the digester tank within predetermined distances.
It is a fourth object of this invention to provide an observation port in the roof member of the digester apparatus and means for rotating the roof member; so that a radially displaced observation port is sufficient for viewing the entire surface of the digester as the roof member is rotated.
A fifth object of this invention is to provide an observation capsule depending from the roof member of the digester and displaced from the center thereof, the observation capsule being of sufficient size to house a human observer.
It is a sixth object of the present invention to provide an observation port in the roof member of a digester apparatus, to provide a means for rotating the roof member, and to provide means for selectively directing a jet of water against the inside surfaces of the digester tank so that the inside of the digester tank can be effectively washed without removing the roof member.
It is a seventh object of this invention to provide control means within an observation capsule which depends from the roof member, for selectively controlling the rotation of the roof member.
It is an eighth object of the present invention to provide a step method for the digesting of organic material anaerobic for the producing of liquid fertilizer and methane gas.
It is a ninth object of the present invention to provide apparatus for the accomplishing of the steps of the step digesting process.
The abovementioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a partial front elevation, in cross-section, of the digester tank of the present invention;
FIG. 2 is an enlarged partial cross-section of the bottom member of the digester tank of FIG. 1;
FIG. 3 is a cross-sectional view taken substantially as shown by section line 3--3 of FIG. 1;
FIG. 4 is an enlarged and cross-sectioned view of a portion of the digester tank of FIG. 1, showing the circumferential sealing well thereof, being taken at a circumferentially displaced location from that of FIG. 1 and showing the electric motor and drive wheel unit for rotating the roof member;
FIG. 5 is an enlarged partial and cross-sectioned view of the digester apparatus of FIG. 1, taken at a second circumferentially displaced location from that of FIG. 4, and showing a guide mechanism;
FIG. 6 is a top plan view of the roof member, showing, diagrammatically, the preferred positions for the drive wheel unit and the guide mechanisms;
FIG. 7 is an enlarged and partial cross-section of the observation capsule of FIG. 1 taken substantially as shown by section line 7--7 of FIG. 1;
FIG. 8 is a partial and enlarged cross-section of the observation capsule of FIG. 1 taken substantially as shown by section line 8--8 of FIG. 1;
FIG. 9 is a schematic drawing of an organic digester system, including a plurality of organic digesters, for accomplishing the step digesting process of the present invention;
FIG. 10 is an enlarged and cross-sectioned view of a portion of the digester tank of FIG. 1, showing the circumferential sealing well thereof, being taken at a circumferentially displaced location from that of FIG. 1, and showing an alternate electric motor and drive wheel unit from that of FIG. 4;
FIG. 11 is an enlarged partial and cross-sectioned view of the digester tank of FIG. 1, taken at a second circumferentially spaced location from that of FIG. 10, and showing an alternate embodiment of the guide mechanism from that which is shown in FIG. 5;
FIG. 12 is an enlarged and partial cross-section of the observation capsule of FIG. 1 taken substantially as shown by section line 12--12 of FIG. 1; and
FIG. 13 is an enlarbged and partial view of the observation capsule of FIG. 1 taken substantially as shown by view line 13--13 of FIG. 12.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, and particularly to FIG. 1, a digester or digester apparatus 20 includes a digester tank 22 and a removable roof member 24. The digester tank 22 includes a circular wall member or circular wall means 26 which is preferably a cylindrically shaped member. The circular wall member 26 includes an upper end 28, a lower end 30, and an inside wall 32. The circular wall member 26 rests upon a circular, ring-shaped footing 34. The footing 34 also supports a conically shaped bottom member 36. The circular wall member 26, the footing 34, and the bottom member 36 are preferably formed of reinforced concrete. A portion of the cylindrically shaped member 26, and the bottom member 36, are placed below grade as shown by grade line 38.
The digester tank 22 includes a slurry filling conduit 40 and a slurry removing conduit 42.
Referring now to FIGS. 1-3, the bottom member 36 includes heating conduit means 44 which is preferably arranged in a spiral configuration in the bottom member 36 and which may include parallel connected branches such as branches 46 and 48. The branches 46 and 48 are connected in parallel to increase the volume flow of hot water which can be circulated through the heating conduit means 44.
Referring again to FIG. 1, the removable roof member 24 includes a gas-impervious plate 50, a conically shaped roof 52, and trusses 54. The digester tank 22 includes an upstanding guide post 55 which is fastened to the bottom member 36, and a guide tube 57 which is fastened to a reinforcing plate 59 and to the plate 50 and which telescopically slides over the guide post 55 to provide a guide means for the roof member 24; so that the roof member raises uniformly on all sides and remains radially centered. Struts 61 provide rigidity between the roof member 24 and the guide tube 57.
Referring now to FIGS. 1, 4, and 5, the digester apparatus 20 includes liquid seal means for providing a gas-tight seal between the digester tank 22 and the roof member 24. The liquid seal means includes a circumferential sealing well 56 which is provided radially outward from the circular wall member 26 and proximal to the upper end 28 thereof. The circumferential sealing well 56 comprises a circumferential space between a circumferential wall 58 and the circular wall member 26. A well bottom portion 60 cooperates with the circumferential wall 58 to connect the wall 58 to the circular wall member 26.
The liquid seal means further includes a circumferential sealing skirt 62 which is attached to the plate 50 and which depends therefrom into the sealing well 56. A liquid 64 provides a gas-tight seal between the digester tank 22 and the roof member 24 and allows both rotary motion and vertical movement between the roof member 24 and the digester tank 22.
Referring now to FIGS. 1, 4, 5, and 6, the digester apparatus of FIG. 1 includes a drive means or electric motor and drive wheel unit 66 of FIG. 4 and a guide means or guide mechanism 68 of FIG. 5.
Referring now to FIG. 4, the electric motor and drive wheel unit 66 includes a drive wheel 69 which is rotatably attached to a gear unit 70 and the gear unit 70 is drivingly attached to an electric motor 72. The gear unit 70 is attached to a pivot arm 74 which is in turn attached to a housing 76, the housing 76 being attached to a base 78 which is an integral part of the bottom portion 60. A spring 80 is interposed between the housing 76 and the pivot arm 74 to resiliently force the drive wheel 69 against a rain-precluding or second circumferential skirt 82 which is attached to the roof member 24 and which depends therefrom in radially outward spaced location from the circumferential sealing skirt 62. Thus the electric motor 72, the gear unit 70, and the drive wheel 69 provide a drive means or rotating means for rotating the roof member 24.
Referring now to FIGS. 5 and 6, a pair of guide means or guide mechanisms 68 are located at two circumferentially spaced positions around the second circumferential skirt 82 as shown in FIG. 6 and provide means for radially guiding the roof member 24 and for balancing the radial force which is imposed by rotating means 66 of FIG. 4. The guide means 68 includes a pedestal, shaft, and bearing assembly 84, a guide roller 86, a base 88 which is an integral portion of the well bottom portion 60, and a housing 90. Optionally, the guide mechanisms 68 may be omitted because of the radial guiding that is provided by the post 55 and the guide tube 57; or optionally, the guide mechanisms may be spring loaded by springs 91 (FIG. 6) to provide resilient radial balancing for the radial force of the spring 80 of the drive means 66.
Referring now to FIGS. 1, 7, and 8, the digester apparatus 20 includes an observation capsule 92 which is inserted into an opening 94 in the plate 50 and which is sealably attached to the plate 50. The observation capsule 92 includes capsule wall means 96 and a floor 98, it being understood that the observation capsule 92 is of sufficient size for receiving a human observer.
The observation capsule 92 includes an observation port or observation port means 100 which comprises a plurality of windows and includes electric lights 99 and 101 for lighting of the interior of the digester tank 22. Access to the observation capsule 92 is by way of a hatch 102 in the conically shaped roof 52.
Referring now to FIGS. 1 and 7, a water nozzle 104 is inserted through the capsule wall means 96 of the observation capsule 92 and is mounted to the capsule wall means 96 by a sealing swivel 106. Inside the observation capsule 92, a handle 108 is provided to rotatably direct the nozzle 104. Intermediate of the handle 108 and water conduit means 110, a swivel fitting 112 is provided to allow the free rotation of the nozzle 104 by the handle 108.
Referring now to FIGS. 1 and 8, an alternate design includes a nozzle 114 which is sealably mounted in the capsule wall means 96 by the use of a universal swivel 116. The nozzle 114 includes a handle portion 118 for controllably directing fluid from the nozzle 114 against the inside walls 32 of the circular wall member 26 and against the inside bottom surface 120 of the bottom member 36. The nozzle 114 is supplied with water from a flexible conduit means 122 which allows the universal swiveling of the nozzle 114.
Referring again to FIGS. 1, 7, and 8, pressurized water is supplied to the nozzle 104 of FIG. 7 or to the nozzle 114 of FIG. 8 by way of a boom 124. The boom 124 includes a water conduit 126, an electrical conduit 128, a strut 130, a truss member 132, and swivel fittings 134 and 136.
The boom 124 also includes an inner post 138 which is attached at the bottom end thereof to the plate 50, and an outer post 140 which is attached to the conically shaped roof 52. The inner post 138 is sealably inserted into the swivel fitting 136; so that water from the water conduit 126 flows between the inner post 138 and the outer post 140 and then into a water conduit 142. The water conduit 142 is then either connected to the water conduit means 110 of FIG. 7 or to the flexible conduit means 122 of FIG. 8. The swivel fitting 134 provides for relative rotary motion between the boom 124 and the roof member 24 and for the transmission of electrical power from the electrical conduit 128 to an electrical conduit 143. In like manner, the swivel fitting 136 provides for relative rotary motion between the boom 124 and the roof member 24 and for the transmission of pressurized water from the conduit 126 to the conduit 142.
Referring now to FIGS. 4, 7, and 8, an electrical switch 146 is provided in the observation capsule 92 and is connected by wires (not shown) to the rotating means 66 of FIG. 4 by means of the electrical conduit 128 of FIG. 1 to provide manually selective control of the rotating means 66.
Referring again to FIGS. 4 and 5, a layer of insulating material 148 is attached to the outer surface of the circumferential wall 58 to restrict the flow of heat from the liquid 64, through the circumferential wall 58, to a cold atmosphere thereby effectively preventing freezing of the liquid 64.
Referring now to FIG. 10, in an alternate embodiment of the present invention, the electric motor 72 and the gear unit 70 are pivotally attached to a drive housing 222 by the pivot arm 74, the drive housing 222 being attached to the roof member 24 and replacing a portion of the second circumferential skirt (FIG. 4). The drive wheel 69, which is driven by the electric motor 72 and the gear unit 70 is resiliently urged by the spring 80 into operative engagement with the periphery of the digester tank 20.
Referring now to FIG. 11, the guide roller 86 is rotatably mounted to a roller housing 224 by a pedestal, shaft, and bearing assembly 226 in a location wherein the drive roller 86 operatively engages the periphery of the digester tank 22. The roller housing 224 is connected to the roof member 24 and replaces a portion of the second circumferential skirt 82. In like manner as with the embodiment of FIG. 5, a pair of the guide rollers 86 may be located as shown in FIG. 6 and may be either rigidly mounted as shown in FIG. 11 or may be spring loaded by the springs 91 of FIG. 6.
Referring now to FIG. 12, in an alternate embodiment, the observation capsule 92 is provided with a video camera 228 for remotely viewing the inside of the digester tank 22. The video camera 228 is connected to a video monitor 230 which is located externally of the digester apparatus 20 and at any proximal or distal location as desired. A roof rotating control switch 232 is provided proximal to the video monitor 230, is operatively connected to the electric motor 72 (FIG. 10), and is effective to selectively control the rotation of the roof member 24.
Referring now to FIGS. 12 and 13, and more particularly to FIG. 13, the window 100 includes an inside surface 233 which is proximal to the inside of the digester tank 22 and which is distal from the inside of the observation capsule 92. The observation capsule 92 is provided with windshield washer means which includes jets 234 and 236 which are adapted to spray water or other cleaning fluid onto the inside surface 233 of the window 100. The observation capsule 92 is also provided with windshield wiper means which includes a pair of wiper blades 238 and 240 which are operatively connected to and driven by a pair of wiper motors 242 and 244.
Referring now to FIG. 9, an organic digester system 150 includes a plurality of the digesters or digester apparatus 20 such as has been previously described. Each digester apparatus 20 is diagrammatically represented both from front elevation and top views, it being understood that the separate representations do not represent separate digesters, but instead provide a means for more clearly depicting the connections of the various conduits and other components.
The organic digester system includes a collecting digester 20a, a first stage digester 20b, a second stage digester 20c, and a final stage digester 20d.
The slurry conduit and pumping system includes a receiving station 152 which is connected to a valve and header assembly 154, and the header system 154 is connected to a slurry pump 156 by a conduit 158. The valve and header assembly 154 is connected to the digesters 20a-20d by slurry removing conduits 42a-42d respectively. In like manner, the slurry pump 156 is connected to a valve and header assembly 160 by conduit 162; and the valve and header assembly 160 is connected to the digesters 20a-20d by slurry filling conduits 40a-40d respectively to deposit organic material into the respective digesters. A fertilizer removal station 164 includes a conduit 166 which is connected to the valve and header assembly 160 and a bulk fluid meter 168 which is interposed into the conduit 166 and which provides a means for measuring the quantity of liquid fertilizer that is discharged from the final stage digester 20d.
Referring now to the portion of FIG. 9 which depicts the gas handling system, each of the digesters 20 is equipped with a roof height sensing switch 170 which is adapted to provide or to break an electrical connection depending upon predetermined upper and lower positions of the roof member 24, the position sensing function of the switch 170 being depicted by a finger 172. A solenoid valve 174 is connected to each digester apparatus 20 at a point above the slurry level therein by a gas conduit 176. Each solenoid valve 174 is connected to a respective one of the roof height sensing switches 170 by an electrical conduit 178. Each solenoid valve 174 is further connected to a gas receiving tank 180 by conduits 182 and by a gas compressor 184. Interposed into the conduits 182 is a gas volume meter 186 for the measuring of the methane gas which is produced by each digester apparatus 20.
Each of the roof height sensing switches 170 is connected to an engine starting conductor 188 by a diode 190 so that the engine starting conductor 188 is energized by any one of the switches 170.
The gas compressor 184 is operated by an internal combustion engine 192 which is operated by methane gas received from the tank 180 through a conduit 194. The engine 192 is equipped with a battery and starter unit 196 which is in turn connected to the engine starting conductor 188. Thus, in accordance with predetermined roof heights of the roof member 24, the switches 170 and the solenoid valves 174 are effective to cooperate with the gas compressor 184 and the gas receiving tank 180 to remove methane gas from any one of the digester apparatus 20 to maintain the height of the respective roof members between predetermined upper and lower limits.
Referring again to FIG. 9, the slurry pump 156 is driven by an internal combustion engine 198 which is likewise furnished with gas from tank 180 and conduit 194 and which also includes a battery and starter unit 200. The battery and starter unit 200 is provided with a manual control station 202 for selectively starting the engine 198 and operating the slurry pump 156.
The system 150 includes an internal combustion engine 204, a battery and starter unit 206, and a starter control station 208. The engine 204 is connected to an alternator 210 to provide electrical power in electrical conductors 212.
The organic system 150 further includes a gas fired water boiler 214 which receives methane gas from the tank 180, which burns the methane gas, and which heats water for circulation to the heating conduit means 44 in each of the digester tanks 22. The water boiler 214 is connected to each of the digester apparatus 20 by a supply conduit 216 and a return conduit 218. Interposed between the conduits 216 and each of the heating conduit means 44 of each digester apparatus 20 is a thermostatically controlled water valve 220 for the maintaining of the slurry temperature between predetermined limits.
From the foregoing description it can be seen that the organic digester system 150 manufactures liquid fertilizer and methane gas, that this methane gas is used for powering the engine 192 which drives the gas compressor 184, for powering the engine 198 which drives the slurry pump 156, and for powering the engine 204 which drives the alternator 210. Thus the system 150 is effective to provide gas and electrical power for operation of the step digester system 150 and is also effective to provide additional gas and electrical power for other uses on a farm.
In operation of the system, referring again to FIG. 9, manure, fecal excrement, or other organic material is placed into the receiving station 152, and if necessary, mixed with water to obtain a consistency which can be pumped through the various conduits. The valve and header assemblies 154 and 160 are manually actuated to interconnect the receiving station 152 with the collecting digester 20a by way of the slurry pump 156; and the organic material in the receiving station 152 is deposited in the collecting digester 20a. The collecting digester 20a may be completely filled during a period of one day or less or it may be filled over a period which is equal to the cycle time in each of the other digesters 20.
The organic material in the collecting digester 20a is heated to the temperature range 90 degrees to 105 degrees Fahrenheit by the heating conduit means 44 (FIGS. 2 & 3); but if, during cold weather, the temperature of organic material in the organic digester 20a falls below the 90 degree Fahrenheit temperature, due to the introduction of cold organic material, the process is not harmed; since this same organic material will subsequently be maintained within the prescribed temperature limits in the succeeding digesters. Thus, it can be seen that the time, temperature, and method of introduction of the organic material into the collecting digester 20a does not affect the quality of the fertilizer being manufactured.
The organic material in the collecting digester 20a is subsequently transferred to the first stage digester 20b, from the first digester 20b to the second stage digester 20c, and then to the final stage digester 20d, this same quantity of organic material being held in each digester for a period of at least seven days. Preferably, this quantity of organic material is held in each digester 20 for a period of fifteen days; so that any given quantity or batch of organic material is in the digesters 20 for a total of at least forty-five days plus whatever time this same quantity of organic material might have been in the collecting digester 20a.
Transferring of organic material from one of the digesters 20 to another of the digesters 20 is accomplished by actuating the valve and header assemblies 154 and 160 to interconnect respective ones of the conduits 42 and 40 so that the organic material is drawn from one of the conduits 42, through the slurry pump 156 and through one of the conduits 40 to another of the digesters 20.
It should be understood that, at any given time, there will be different batches of organic material being processed in each of the digesters; so that the process is a step process with different batches of organic material being in respective ones of the steps of the step digesting process.
For the removal of completely processed organic material from the final stage digester, that is, for the removal of liquid fertilizer from the final stage digester 20d, the valve and header assemblies 154 and 160 are first actuated to pump liquid fertilizer from the final stage digester 20d through the conduit 42d, through the pump 156, and through the conduit 40a to the collecting digester 20a. This process is used to flush the conduits 158 and 162 and thereby to completely remove undigested organic material from these conduits. Then the valve and header assembly 160 is actuated to interconnect the conduit 42d with the conduit 166; and thereby to pump liquid fertilizer from the final stage digester 20d through the conduit 166 and through the bulk fluid meter 168 into a tank truck (not shown).
Referring now to FIGS. 1 and 9, methane gas will be produced in various quantities in all of the digesters 20. The digester apparatus 20 of FIG. 1, which is typical of all of the digesters of FIG. 9, is designed so that the roof member 24 raises and lowers to provide a storage vessel for the gas which is produced in the digester apparatus 20. This gas is maintained at a pressure of three to six inches of water, the pressure being controlled by the weight of the removable roof member 24, and, if necessary, the addition of weights (not shown) to the conically shaped roof 52. The height of the roof is controlled by the volume of gas within the digester apparatus 20, and the volume of gas within the digester apparatus 20 is controlled by the roof height sensing switch 170 and the solenoid valve 174 of FIG. 9.
The seal between the roof member 24 and the digester tank 22 is maintained by the liquid 64 in the circumferential sealing well 56. The liquid 64 may be water, water plus an antifreeze, or oil. When there is no gas pressure in the digester apparatus 20, the level of the liquid 64 will be as shown in FIG. 4, but with gas pressure within the digester apparatus 20, the liquid levels on opposite sides of the circumferential sealing skirt 62 will be as shown in FIG. 5.
Referring again to FIG. 9, it is desirable to intermittently agitate the slurry during the digesting process. The system 150 of the present system utilizes the slurry pump 156 to recirculatingly pump slurry from any of the digesters and the respective one of the conduits 42 back into the same one of the digesters 20 via the respective one of the conduits 40. Thus the system 150 includes an agitating means which comprises the slurry pump 156.
When any of the digesters 20 is emptied of slurry or liquid fertilizer, it is necessary to replace the volume of liquid that is removed with a sufficient volume of gas or air to prevent an excessively high vacuum in the digester 20 which could possibly collapse the roof member 24. Preferably, air is excluded from the digester 20, and gas from the tank 180 is returned to the digester 20 to maintain the gas pressure in each of the digesters 20 at three to six inches of water and to maintain the respective ones of roof members 24 in suspended positions. Thus, when a digester 20 is emptied of slurry or liquid fertilizer, the roof member 24 is easily rotated for the washing process because it is floated on the gas inside the digester 20.
In a typical system, each digester apparatus 20 will be 50 feet in diameter and the gas receiving tank 180 will be of 30,000 gallon capacity.
The digesting method includes: depositing organic material into the collecting digester 20a at any time during a period which is equal to the retention time in each of the succeeding digesters, transferring the organic material successively to the succeeding digester 20, and retaining each batch or organic material in each of the digesters 20b-20d for a period of at least seven days, but preferably fifteen days.
Referring to FIG. 1, the method of washing the digester apparatus includes: observing the inside walls 32 and the inside bottom surface 120 through the observation port means 100, controllably rotating the roof member 24 by manual actuation of the electrical switch 146 (FIGS. 7 & 8), and manually directing a jet of water from the nozzle 104 (FIG. 7) or the nozzle 114 (FIG. 8) against the inside wall 32 and the inside bottom surface 120.
In summary, the present invention provides a liquid seal means between a digester tank 22 and a roof member 24 so the roof member 24 may be raised and lowered or rotated without breaking the gas seal between the digester tank 22 and the roof member 24 which is provided by the liquid seal means. Being able to raise and lower the roof member 24 provides a change in volume within the digester apparatus 20 for the effective storing of the methane gas which is being produced; whereas, being able to rotate the roof member 24 allows the complete inspection of the inside walls 32 and the inside bottom surface 120 by a single window or observation port means 100 which is radially displaced from the center of the roof member 24. In addition, the floating of the roof member 24 on the methane gas is effective to reduce the friction between roof member 24 and the digester tank 22 for rotation of the roof member 24 by very low power. Further, the ability to rotate the roof member 24 makes it possible to wash the inner surfaces of the digester tank 22 by a manually directable water nozzle mounted in each of the roof members 24 in a position radially displaced from the center thereof. Further, in the preferred configuration, the digester apparatus 20 includes the observation capsule 92 from which the operator can observe the washing process and direct the water from the nozzle 104, or the nozzle 114 (FIGS. 7 or 8) against the inside wall 32 and the inside bottom surface 120.
The present invention allows the introduction of organic material into the collecting digester 20a at any time, in any quantity, and at any temperature, without affecting the digesting process of the system or the quality of the fertilizer being produced.
That is, fresh manure is slightly acid but changes to be slightly alkaline during the anaerobic digesting process. Thus, the addition of fresh manure, into a digester in which the complete digesting process is performed, would interfere with the digesting process by unbalancing the pH of the slurry. However, in the present invention, the step digesting apparatus and method prevent fresh manure from being introduced into any digester except for the collecting digester and the first stage digester; and no organic material is deposited into the first stage digester except after it has been emptied. Thus, the pH of the last three digesters cannot be upset, the total time in the last three digesters is sufficient to completely digest the organic material, and so high quality fertilizer is produced without regard to the times of depositing manure into the collecting digester and without regard to the quantities of manure which is deposited therein at the time of each deposit.
In like manner, the introduction of cold manure into the collecting digester will not affect the operation of the process because the organic material is completely digested in the last three digesters without regard to whatever digesting may have occurred in the collecting digester.
Further, the present invention produces methane gas for the heating of the water and for maintaining the temperature of the organic material in the digester, for operating gas engines for pumping of slurry and gas, for operating a gas engine to produce electricity for use on the farm, and for producing additional gas and electricity for use in heating, lighting, and powering the farm. The primary product of the system, which is high quality organic fertilizer, is, as generally known, highly superior to chemical fertilizer for its long-range effects on the soil.
As an additional benefit, stream pollution from the run-off of animal manure is prevented and obnoxious odors are effectively reduced so that the ecology is enhanced. In short, the system of the present invention both saves energy and improves the ecology.
While there have been described above the principles of this invention in connection with specific apparatus and specific method, it is to be clearly understood that this description is made only by way of an example and not as a limitation to the scope of the invention. | A method is provided for washing the inside of an organic digester of the type having a rotatable roof member. The method includes supporting the roof member, with pressurized gas excluding oxygen, rotating the roof member, spraying water on the interior walls of the digester, and observing the washing process. |
RELATED APPLICATION
[0001] The present application claims priority from and the benefit of U.S. Provisional Patent Application No. 61/658,194, filed Jun. 11, 2012, the disclosure of which is hereby incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to communications patching systems, and more particularly to intelligent communications patching systems.
BACKGROUND
[0003] FIG. 1 illustrates a patching system 10 that may be used to connect computers, printers and other “work area” end devices 20 to network equipment that is located in a computer room 14 . The patching system of FIG. 1 may also be used to interconnect devices in a data center. As shown in FIG. 1 , an end device 20 (which is illustrated as being a computer, but could be other end devices such as printers, facsimile machines, etc.) that is located in a work area 12 is connected by a patch cord 22 (a patch cord is a cable that has a plug connector on at least one end thereof) to a modular wall jack 24 . A so-called “horizontal” communications cable 28 is routed from the back end of the wall jack 24 through the walls of the building to the computer room 14 . While only a single work area end device (computer 20 ) is shown in FIG. 1 , it will be appreciated that a typical system includes hundreds or thousands of work area end devices 20 , wall jacks 24 and horizontal cables 28 .
[0004] As is further shown in FIG. 1 , a plurality of patch panels 32 are mounted on a first equipment rack 30 in the computer room 14 . A patch panel refers to a frame that includes a plurality (e.g., 24 ) of connector ports 34 mounted thereon. Each of these connector ports 34 has a back end that receives a communications cable (e.g., a cable 28 ) and a front side that includes a plug aperture that receives the plug of a patch cord. The connector ports 34 are used to electrically connect a patch cord to a communications cable. Each horizontal cable 28 from the wall jacks 24 in the work area 12 is terminated onto the back end of one of the connector ports 34 of one of the patch panels 32 . A second set of patch panels 32 ′ that have connector ports 34 ′ are mounted on a second equipment rack 30 ′. A first set of patch cords 50 is used to interconnect the connector ports 34 on the patch panels 32 to respective connector ports 34 ′ on the patch panels 32 ′. Rack controllers 36 are provided on each equipment rack 30 , 30 ′ that pass information from the patch panels 32 , 32 ′ to a system administrator computer (not shown), as is discussed below.
[0005] Network devices such as network switches 42 and network routers and/or servers 46 are mounted on a third equipment rack 40 . Each of the network switches 42 has a plurality of connector ports 44 , and each network router and/or server 46 also includes one or more connector ports. An external communications line 52 is connected to one of the network devices 46 . A second set of single-ended patch cords 70 connect the connector ports 44 on the network switches 42 to respective ones of the back ends of the connector ports 34 ′ on the patch panels 32 ′. A third set of patch cords 54 interconnect other of the connector ports 44 on the switches 42 with the connector ports on the network routers/servers 46 . The cables 28 , patch panels 32 , 32 ′ and patch cords 50 , 70 are used to connect each wall jack 24 to a respective connector port 44 on the network switches 42 .
[0006] Communications from a particular work area end device (e.g., computer 20 ) are transmitted over the patch cord 22 , through the wall jack 24 , over the cable 28 , and through the patch panels 32 , 32 ′ and patch cords 50 , 70 to one of the network switches 42 , and this network switch 42 then routes those communications towards their intended destination (e.g., to another work area device 20 , a network device 46 , or to the external communication line 52 for transmission over the Internet). The network switches 42 likewise receive communications from internal or external sources and route these communications to the intended work area devices 20 .
[0007] It may become necessary to change the connections between particular modular wall jacks 24 and the connector ports 44 on the network switches 42 for a variety of reasons such as employee office moves, providing additional capabilities (e.g., support for an Internet telephone) to particular offices and the like. The patch panels 32 , 32 ′ are provided to facilitate such connectivity changes, as a system administrator need only rearrange one of the patch cords 50 that interconnect a connector port 34 on one of the patch panels 32 with respective connector port 34 ′ on one of the patch panels 32 ′ to effect an end-to-end connectivity change that connects a particular end device 20 to a different connector port 44 on one of the network switches 42 . Each time such a connectivity change is made the change is recorded in a computer-based connectivity log that keeps track of all of the connections between the wall jacks 24 and the connector ports 44 on the network switches 42 .
[0008] The system of FIG. 1 is referred to as a “cross-connect” patching system, as two separate sets of patch panels 32 , 32 ′ are provided, and connectivity changes are made by rearranging the patch cords 50 that extend between the two sets of patch panels 32 , 32 ′. In another configuration that is referred to as an “interconnect” patching system, the second set of patch panels 32 ′ and the second set of patch cords 70 are omitted, and instead the connector ports 34 on the first set of patch panels 32 are connected directly to the connector ports 44 on the network switches 42 by the patch cords 50 . Interconnect patching systems require less equipment, but as is discussed below, may have less capabilities.
[0009] Unfortunately, computer-based connectivity logs often are replete with errors because of incorrect entries or because a technician forgets to enter a particular connectivity change into the log. In complex networks, it can be very difficult to identify and correct there errors. Accordingly, various “intelligent” patching systems have been proposed that sense connectivity changes and automatically update the computer-based connectivity log each time such changes are made.
[0010] One such patching system (available from CommScope, Inc., Hickory, N.C. under the name iPATCH) includes so-called “intelligent” patch panels 32 , 32 ′ that work in conjunction with the rack controllers 36 and “system administrator” software (which runs on a control computer) to automatically track the connections between each wall jack 24 and its respective connector port 44 on one of the network switches 42 . This system may be implemented in both cross-connect and interconnect patching configurations.
[0011] The system uses “intelligent” patch panels 32 , 32 ′ that include sensors on each connector port 34 , 34 ′ that detect each time the plug on a patch cord 50 is plugged into, or removed from, the connector ports 34 , 34 ′. Each connector port 34 , 34 ′ also includes an associated light-emitting diode (“LED”) that may be automatically lit to help guide a technician to the connector port 34 , 34 ′, and may also have an associated trace button that a technician may press in order to light the LED on the connector port 34 , 34 ′ that the far end of a patch cord 50 is plugged into. Operations of the system will now be explained in the cross-connect and interconnect environments, respectively.
[0012] When the horizontal cabling 28 for a cross-connect patching system is first installed, a connectivity database is created, and the system administrator installing the network records in this database the connections between each wall jack 24 and its associated connector port 34 on the patch panels 32 . As the horizontal cables 28 are hard-wired (as opposed to plug-in) connections that run through the walls of the building, these connections are assumed to be constant connections that never change. The system administrator likewise manually inputs into the connectivity database the connections between the connector ports 44 on each network switch 42 and their corresponding connector ports 34 ′ on the patch panels 32 ′ (i.e., the administrator enters into the connectivity database the end points of each single-ended patch cord 70 in FIG. 1 ). While these connections are more subject to change (since each patch cord 70 has a plug on one end thereof that plugs into one of the switch connector ports 44 ), once again it is assumed that these connections will not change (or at least that if they do change, the administrator will update the connectivity database to reflect these changes). Thus, the connections between the wall jacks 24 and the patch panels 32 are known in advance, as are the connections between the network switches 42 and the patch panels 32 ′. What is not known are the connections formed by the patch cords 50 between the patch panels 32 and the patch panels 32 ′. These connections are automatically determined by the aforementioned cross-connect system as follows.
[0013] When a new patch cord 50 is to be connected between the patch panels 32 and 32 ′, the sensor on the connector port 34 , 34 ′ that the first end of this new patch cord 50 is plugged into senses the plug insertion, and notifies the system administrator software (via the rack manager 36 ) of this plug insertion. Thereafter the second end of the new patch cord 50 is plugged into another of the connector ports 34 , 34 ′, and the system administrator software then assumes that these two back-to-back plug insertions represent the two ends of a new patch cord 50 that has been connected between the patch panels 32 and 32 ′. Since the sensors associated with each of the connector ports 34 , 34 ′ will sense these two patch cord insertions, the system is able to automatically identify the connector ports 34 , 34 ′ that the new patch cord 50 extends between. This information is added to the connectivity database.
[0014] The system also automatically tracks the removal of any of the patch cords 50 and/or changes in the connections formed by any of the patch cords 50 . For example, if a patch cord 50 is removed from one of the connector ports 34 or 34 ′, this removal is sensed by the sensor on the connector ports 34 , 34 ′. Since the iPatch system already knows exactly which connector port 34 , 34 ′ the other end of the patch cord 50 is connected to, the iPatch system then lights the LED associated with that connector port 34 , 34 ′ to help the technician find the far end of the patch cord 50 . The system administrator can then remove the second end of the patch cord 50 , which removal is sensed by the sensor on the connector port 34 , 34 ′. After both ends of the patch cord 50 have been removed, the connection that was previously formed by the patch cord 50 at issue may be deleted from the connectivity database. If the administrator only unplugs one end of one of the patch cords 50 (which removal is sensed by the system) and then proceeds to plug the free end of the patch cord 50 into another one of the connector ports 34 , 34 ′, the system will sense that a patch cord insertion was performed immediately after a patch cord removal as opposed to two patch cord removals occurring back-to-back. In response to sensing such a sequence of events, the system will then ask the system administrator to confirm that he is changing a connection (i.e., unplugging one end of one of the patch cords 50 and then plugging it back into a different connector port 34 , 34 ′) as opposed to removing the patch cord 50 at issue in its entirety. Once the system administrator confirms that a connection change is being made, the system can automatically change the connection information stored in the connectivity database to reflect the connection change. In this manner, the system can automatically track the addition of new connections, the removal of existing connections, and changes to existing connections, and may thus automatically maintain an accurate connectivity database that tracks the connections between each connector port 44 on the network switches 42 and their corresponding modular wall jacks 24 .
[0015] Some patching systems can automatically gather and store additional information regarding the network connections. In such an embodiment, the system administrator software sends control communications to the network switches 42 using Simple Network Management Protocol or “SNMP” commands to access information that is stored in memory at each network switch 42 such as the switch's name, number of connector ports 44 , etc. Each network switch 42 also automatically generates a table that contains (1) the MAC address for each end device 20 that is communicating through the switch 42 (the MAC address is a unique identifier for each end device 20 , and is automatically sensed by the network switch 42 once a device starts communicating through a network switch 42 ) and (2) the connector port 44 on a particular network switch 42 that each such end device 20 is connected to. The system may also use SNMP commands to pull this information from each network switch 42 for storage in the connectivity database. The system may also query an Address Resolution Protocol table (which may be resident on the network switches 42 or located elsewhere in the network) in order to convert each MAC address to an IP address for each end device 20 . Thus, in this manner, the system can automatically track both (1) the physical connections between each modular wall jack 24 and its associated connector port 44 on one of the network switches 42 and (2) the identity of each end device 20 that is accessing the network via the wall jacks 24 .
[0016] There are two different ways that the system may ensure that the identification information regarding the end devices 20 is kept up to date in the connectivity database. The first way is to simply schedule periodic checks (e.g., once an hour) where the system sends SNMP commands to each network switch 42 to request an update regarding the end devices 20 that are connected through the switches 42 . Alternatively, each network switch 42 can send out notifications called SNMP traps each time the network switch 42 senses that a new end device 20 has been connected to the switch 42 (i.e., the network switch 42 sends out an SNMP trap each time the network switch 42 establishes a communication link with a new end device 20 ). In response to this SNMP trap, the system may then request information on the new end device 20 from the network switch 42 . Monitoring end devices in this fashion may be useful, for example, for security purposes.
[0017] As noted above, patching systems may also be used to track an “interconnect” configuration. However, as commercially available network switches 42 do not include sensors at each connector port 44 , the system can only automatically track one end of each patching connection (recall that in an interconnect-style network the patch cords 50 extend between the patch panels 32 and the network switches 42 , as the patch panels 32 ′ are omitted). To compensate for this, the system can generate a work order each time it is necessary to add, remove or change a connection. Each such work order specifies the connector port 34 on one of the patch panels 32 and the connector port 44 on one of the network switches 42 that are implicated by the connection change. Once the technician makes the connection to the particular connector port 44 on the network switch 42 that is specified in the work order, the technician notifies the system administrator software that the connection has been completed by pressing the trace button associated with the connector port 34 on the patch panel 32 that receives the other end of the patch cord 50 . This system is not foolproof, because it will not detect situations where the technician mistakenly plugs the patch cord 50 into the incorrect connector port 44 on the network switch 42 .
[0018] It will be appreciated that the patching system of FIG. 1 is highly simplified and provided for the purposes of illustration only. Patching systems will typically include tens, hundreds, thousands or tens of thousands of patch panels, which may be subdivided into tens or hundreds of local patching fields. Additional details regarding intelligent patching systems are set forth in U.S. patent application Ser. No. 13/110,994, filed May 19, 2011, the disclosure of which is hereby incorporated herein by reference in its entirety.
SUMMARY
[0019] As a first aspect, embodiments of the invention are directed to a telecommunications patching system having point-to-point tracing capabilities. The patching system comprises: a plurality of end devices; at least one rack structure; a plurality of patch panels mounted to each rack structure; a plurality of connector ports disposed on each of the patch panels; a plurality of patch cords for selectively interconnecting different pairs of connector ports; a plurality of cables for selectively interconnecting the connector ports on the patch panels with respective end devices; tracing modules associated with said connector ports and end devices that monitor connectivity of the connector ports and end devices; and a display associated with the tracing modules configured to display the connectivity of a circuit comprising one or more of the connector ports and one or more of the end devices.
[0020] As a second aspect, embodiments of the present invention are directed to a method of interconnecting telecommunications devices, comprising the steps of: (a) providing an intelligent patch system having: a plurality of end devices; at least one rack structure; a plurality of patch panels mounted to each rack structure; a plurality of connector ports disposed on each of the patch panels; a plurality of patch cords for selectively interconnecting different pairs of connector ports; a plurality of cables for selectively interconnecting the connector ports on the patch panels with respective end devices; tracing modules associated with said connector ports and end devices that monitor connectivity of the connector ports and end devices; and a display associated with the tracing modules configured to display the connectivity of a circuit comprising one or more of the connector ports and one or more of the end devices; (b) moving one of the patch cords from one of the connector ports to another of the connector ports; and (c) illuminating on the display a new patching circuit formed by the patch cord moved in step (b) to verify the correctness of the new patching circuit.
[0021] As a third aspect, embodiments of the present invention are directed to a telecommunications patching system having point-to-point tracing capabilities, comprising: a plurality of end devices; at least one rack structure; a plurality of patch panels mounted to each rack structure; a plurality of connector ports disposed on each of the patch panels; a plurality of patch cords for selectively interconnecting different pairs of connector ports; a plurality of cables for selectively interconnecting the connector ports on the patch panels with respective end devices; tracing modules associated with said connector ports and end devices that monitor connectivity of the connector ports and end devices; and a controller configured to display search results regarding the end devices, patch panels, ports, patch cords and cables.
BRIEF DESCRIPTION OF THE FIGURES
[0022] FIG. 1 is a schematic illustration of a patching system that may be used to connect computers, printers and other “work area” end devices to network equipment that is located in a computer room, or to connect end devices in a data center.
[0023] FIG. 2 is an exemplary display screen image of a connection circuit that can be employed in the patching system of FIG. 1 .
[0024] FIG. 3A is the screen image of FIG. 2 with the “+” icon expanded.
[0025] FIG. 3B is the screen image of FIG. 3A shifted horizontally to display different icons.
DETAILED DESCRIPTION
[0026] The present invention is described with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments that are pictured and described herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It will also be appreciated that the embodiments disclosed herein can be combined in any way and/or combination to provide many additional embodiments.
[0027] Unless otherwise defined, all technical and scientific terms that are used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the above description is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this disclosure, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when an element (e.g., a device, circuit, etc.) is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.
[0028] As discussed above and illustrated in FIG. 1 , intelligent patching systems are known and are widely used in the field today. Nonetheless, intelligent patching systems may benefit from additional features, some of which are intended to provide additional information to cabling technicians working at a rack populated with intelligent patching equipment.
[0029] As one example, an intelligent patching system may include the capability of real-time end-to-end circuit display during patching or circuit trace activity. When the user inserts or removes a patch cord plug at a patch panel or presses the trace button over a patch panel connector port, the rack controller may display graphically the portion of the circuit in question that is located in the local patching field. However, it may also issue a query in real time to the system manager database, requesting end-to-end circuit trace information for the circuit in question. Because the database includes information about the cabling infrastructure and the connectivity of fixed cables at the site, when the requested trace information is received from the system manager, the rack controller can supplement the circuit trace it originally displayed to show the endpoints of the circuit; the user may also have the option of expanding the trace so he can scroll through a trace of the entire end-to-end circuit. Thus, the user can view not only information regarding patching at the patch panels themselves, but also information about the connectivity of fixed cabling at the site.
[0030] The information may be displayed on a monitor of a desktop or laptop computer, a GUI interface, a touchscreen, a tablet, a “smart phone”, or the like. Bluetooth or Near Field Communication wireless connections may be used with the table, smart phone, etc.
[0031] An exemplary display 100 of the circuit information for a cross-connect arrangement is shown in FIG. 2 . In the display of FIG. 2 , a faceplate icon 102 represents the location of the wall jack 24 of the circuit; details identifying the location of the wall jack are set forth on the display 100 below the icon 102 . Panel icons 104 , 106 represent the connector ports 34 , 34 ′ on patch panels 32 , 32 ′ that are included in the circuit, with identifying information regarding these connector ports 34 , 34 ′ set forth below the icons 104 , 106 , A patch cord icon 108 illustrates a connection between the icons 104 , 106 . A data service icon 110 represents the external data service.
[0032] A “+” icon 112 is also shown between the data service icon 110 and the patch panel icon 106 . This icon 112 can be expanded (via touch screen, mouse click or the like) to display additional information or connections within the circuit. FIG. 3A shows the display of FIG. 2 with the “+” icon 112 expanded to reveal information about a switch 114 . As shown in FIG. 3B , the user may scroll left or right to display different components or connections.
[0033] Those skilled in this art will recognize that other icons representing other components or connections may also be employed, including: personal computers; phones; printers; fax machines; wireless access points; consolidation points; splice enclosures; mainframe computers; server computers; LAN switches; environmental monitoring devices; storage devices (in storage area networks); private branch exchanges; point-of-sale terminals; and security cameras.
[0034] The real-time display of the endpoint information may be particularly useful to technicians during patching, as it may allow them to verify that the patch cord connection they have made has indeed connected the intended equipment (for example, a particular LAN switch port to a particular desktop computer). The end-to-end trace information may be updated in real time each time the user inserts or removes a patch cord plug; such information is particularly useful when it is displayed at the patch panel or rack at which the user is working. For example, if the user removes one end of an existing patch cord, the display may show not only the two connector ports in the local closet that have been disconnected, but also the endpoints of the circuit that has been broken. If the user then places the free end of the patch cord in question in a different connector port, the trace information may be updated on the right side of the screen to show both the new patch panel connector port and the endpoint of the new circuit that has been created. If the user is not satisfied with this connection, and moves the patch cord plug to yet another connector port, the trace information may be updated accordingly. All of this information can help the user to validate patching connections and changes, including starting and destination ports.
[0035] In another embodiment, an intelligent patching system may include real-time search capabilities. The rack controller 36 may have a touch-screen or other display that allows the user to enter text information. Using this data entry mechanism, users may be able to search for nodes in the cabling system (such as a particular wall jack faceplate or telecom outlet), and/or for equipment attached to the cabling system (such as a computer with a particular IP address or MAC ID, or a switch port assigned to a particular VLAN). Exemplary searchable items include: device names; IP addresses (either specifically or within a range); VLAN IDs; MAC addresses; faceplate names; switch names; work order IDs; cable IDs; cable types' and services.
[0036] Once the user has entered the query information, the rack controller sends the request to the system manager, which queries its database and returns the requested information. This information may be displayed to the user on the rack controller's graphical display. If the circuit in question passes through the patching zone where the rack controller used for the query is located, it will light the LED(s) of any panel ports that are utilized in the circuit in question; if not, the user may still be able to determine from the display which other wiring closet local patching field or the like he may visit in order to access the circuit in question.
[0037] As an enhancement to this embodiment, it would be possible to provide the user an option that would light the LEDs in all panel ports at the site that are used to implement the circuit in question. This variation may facilitate location of patch cords associated with the circuit at each wiring closet through which the circuit passes. Thus, by identifying a circuit with one of the search term identifiers, the user can have the ports associated with that circuit illuminated for easy identification, which in turn can facilitate patching validation and changes.
[0038] The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein. | A telecommunications patching system having point-to-point tracing capabilities includes: a plurality of end devices; at least one rack structure; a plurality of patch panels mounted to each rack structure; a plurality of connector ports disposed on each of the patch panels; a plurality of patch cords for selectively interconnecting different pairs of connector ports; a plurality of cables for selectively interconnecting the connector ports on the patch panels with respective end devices; tracing modules associated with said connector ports and end devices that monitor connectivity of the connector ports and end devices; and a display associated with the tracing modules configured to display the connectivity of a circuit comprising one or more of the connector ports and one or more of the end devices. |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No. 08/287,647, filed Aug. 9, 1994, now abandoned, for "Heat Treating, Annealing and Tunnel Furnace Rolls"; and "Composite Centrifugally Cast Furnace Roll Rings for Furnace Rolls and Method for Making Same", Ser. No. 08/383,578, filed Feb. 3, 1995.
BACKGROUND OF THE INVENTION
This invention is related to a multi-cast furnace roll having an outer layer centrifugally cast of a material that is relatively insoluble with respect to the steel strip being transferred in a furnace, and an inner layer or body of a steel alloy that has high tensile and creep strength and is relatively unweldable to the outer layer. The outer layer and the inner layer are centrifugally cast to fuse the two layers together.
In my aforementioned co-pending application, I disclosed a centrifugally cast furnace roll, and rings that can be used on such rolls, having an outer layer selected of a material having a low solubility, high hardness, and low surface energy so the roll does not adhere to a steel strip being transferred in the furnace. I also disclosed a method for centrifugally casting an inner layer to the inside of the outer layer while it is still in a molten state.
The outer layer was formed by introducing the outer layer alloy into a rotating mold and then advancing the source of the first alloy from one end of the mold toward the other end to form an elongated tube.
The inner layer was then formed by introducing the molten second alloy material within the outer layer in the same starting position as the first alloy material was introduced, and then longitudinally advancing the source of the material in the same direction as the first alloy was delivered to the mold.
While such a method provides a satisfactory roll, the length of the roll is limited because the outer layer gradually cools before the inner layer is cast. The two layers form a satisfactory interface at those points where the difference in temperature does not exceed approximately 200° F., depending on the alloys temperature at the casting moment. When the downstream ends of the two layers begins to exceed 200° F., the two layers separate as they cool. The two layers do not form a satisfactory solution at their interface if the difference in temperature exceeds approximately 200° F.
SUMMARY OF THE INVENTION
The broad purpose of the present invention is to provide an improved casting technique for forming a multi-cast roll. One improvement is that rather than using a spout that advances longitudinally along the inner length of the mold, the molten metal is introduced through a nozzle at one end of the mold, which we will refer to as the hot end. The metal then spirals longitudinally along the length of the mold as the mold is being rotated about its longitudinal axis, forming an outer layer of a uniform thickness. The mold could be slightly inclined to accelerate the metal distribution.
Rather than introducing both alloys into the same end of the mold, the second alloy is then introduced into the opposite end of the mold, that is into the down stream end of the first alloy, thus reducing the temperature difference between the alloy layers at both ends of the mold. The second alloy then spirals along the inside surface of the outer layer at a temperature such that the two layers form an interface of a solution of the two alloys thereby fusing the inner layer to the outer layer.
In another embodiment of the invention, the outer layer alloy is introduced simultaneously into both ends of the mold. The two metals spiral toward one another, forming a continuous outer layer when they meet in the center of the mold.
Then, the second alloy is introduced through both ends of the mold inside the outer layer to form the inner layer.
One advantage of introducing the two alloys from both ends of the mold is that the roll is casted at a higher speed. A satisfactory roll can be formed that is twice the length of a roll formed by introducing both alloys into the same end of the mold.
Another purpose is to provide a variation to the ring roll design fabrication.
In some instances when the particular application requires a large number of rings (for example, when the strip being carried is very thin or when the roll is very long) it may be more economical, than welding the multi-cast rings, to cast a multi-cast roll then machining off a portion of the outer layer to the solution zone or interface to generate the rings. This procedure eliminates the need for:
a) casting a separate roll body;
b) machining the inside diameter of the ring and the outside diameter of the roll body to match;
c) welding the rings to the roll body;
d) for a given ring outside diameter, the roll body outside diameter can be made larger, thus increasing the section modulus and consequently reducing the amount of casted material required to overcome the bending stresses.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.
DESCRIPTION OF THE DRAWINGS
The description refers to the accompanying drawings in which like reference characters refer to like parts throughout the several views, and in which:
FIG. 1 illustrates the cross-section of a preferred multi-casted furnace roll for transferring a strip of steel in an annealing furnace;
FIG. 2 is an enlarged cross-sectional view of the roll of FIG. 1;
FIG. 3 illustrates the preferred method employed for casting the outer layer of the roll;
FIG. 4 shows the next step in forming the inner layer of the roll of FIG. 3;
FIG. 5 shows the preferred method used for introducing the first alloy from both ends of the mold;
FIG. 6 illustrates the method of FIG. 5 in which the second layer is introduced into both ends of the mold;
FIG. 7 illustrates a multi-cast roll with axially spaced rings;
FIG. 8 illustrates the savings in using a roll with unitary rings compared to a roll with welded rings; and
FIG. 9 is a cross-sectional area of a roll.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates the cross-section of a ringless roll 10, made in accordance with the invention and used for transferring an alloy steel alloy strip 12 having a cross-section illustrated in phantom. The strip may be formed of a stainless steel (300 or 400 series) alloy. Roll 10 has a multi-cast tubular body 14 connected by a pair of bell shaped end sections 16 and 18 to a pair of end shafts 20 and 22, respectively. The end shafts are axially aligned and adapted to support the roll for rotation about axis 24.
For illustrative purposes, the body of the roll has a length of about 90 inches, an outer diameter of 51/8 inches, and an inner diameter of 31/8 inches. The roll comprises an outer layer 26 of a steel alloy, and an inner layer 28 of a second steel alloy. The outer layer has a radial thickness of about 0.400 inches. Outer layer 26 is formed of an alloy that has low surface energy, high hardness and is relatively insoluble with the material of strip 12, being conveyed. The outer layer forms a support layer for alloy strip 12. Inner layer 28 has a thickness chosen to accommodate the stresses generated by the strip load, the strip motion, the roll geometry and the furnace operating temperature. It is normally several times the thickness of outer layer 26.
Inner layer 28 is centrifugally cast inside the outer layer while outer layer 26 is still sufficiently hot so that the two alloys fuse along an interface 30 generally illustrated by a series of x's in FIGS. 1 and 2. Outer layer 26 may be a Nicrom 8 steel alloy, available from Alphatech, Inc. of Trenton, Mich.. This alloy is very hard, relatively insoluble and exhibits low or no adhesion with respect to the strip 12 material. The inner layer material may be a Nicrom 72 steel alloy, also available from Alphatech, Inc. Inner layer 28 may be readily welded, for example, to bell shaped sections 16 and 18 after the roll has cooled from the casting process and properly machined.
The roll may be longitudinally divided into rings that can be attached to the outside of a roll body, or the outer layer can be machined to create the rings on the roll of the width and quantity required.
A centrifugal casting apparatus illustrated in FIGS. 3 and 4 comprises an elongated tubular mold 32 which is rotated about its longitudinal axis in the direction of arrow 33. The mold is longitudinally fixed by means not shown. Initially a source 34, such as a ladle, of the outer layer or first alloy is introduced in molten form through a feed nozzle 36 at one end of mold 32 as the mold is being rotated. The molten alloy may be about 2800° F., depending on the final alloy composition. The mold is rotated at approximately 1000 rpm. The first alloy is introduced into the mold and contacts the rotating inside surface 38 of the mold. The alloy then spirals from mold end 40 toward mold end 42, in the direction of arrow 43, forming an outer layer 26 having a relatively uniform thickness. The process is continued until the first alloy has spiraled the length of the mold to form an outer tubular layer.
As soon as the outer layer has been formed to a suitable thickness, delivery of the first alloy from source 34 is terminated. A second alloy, as illustrated in FIG. 4, is introduced from a second ladle or source 44 through a second feed nozzle 46 into end 42 of the tubular mold. The second alloy is introduced inside the rotating outer layer where the interflow of the two molten alloys fuse together in a solution of the two alloys. The fusion progresses in the direction of arrow 48 toward end 40 of the mold. The two layers form a fused joint 30 having a thickness of about 3/4 to 1 inch, as illustrated in FIG. 2. Increased or decreased thicknesses may be required depending on the final roll dimensions and application.
When the inner layer has been formed along the full length of the mold, the user terminates delivery of the second alloy from source 44. The multi-cast body 14 is removed from mold 32 and permitted to cool. It is then machined and welded to the remainder of the roll assembly.
FIGS. 5 and 6 illustrate another method for casting multi-cast body 14. In this embodiment of the invention, both sources 34 and 44 initially simultaneously introduce the first alloy in a molten state from both feed nozzles 36 and 46. The first alloy spirals from the two ends of the mold toward one another and the mid-section of the rotating mold. The two alloys contact one another at the mid-section of the mold, thereby forming an outer layer of an adequate thickness.
The second alloy is then introduced simultaneously into both ends of the mold through feed pipe nozzles 36 and 46, as illustrated in FIG. 6, inside the outer layer of the first alloy. Alloys from both ends spiral toward one another to form an inner layer that progressively forms a fused joint between the two layers.
Body 14 has an outer layer formed of a relatively insoluble non-weldable low or non-adhesion material, while the inner layer is formed of a material having good weldability and strength characteristics.
FIG. 7 illustrates a multi-cast ringed roll made in accordance with the invention and including an inner layer 28, an outer layer 26, and a fused interface 30 of the two layers. In some conditions, it is preferable to reduce the contact between the roll and the strip being transferred in the furnace. For those situations, roll 10 has annular grooves or recesses 50, 52, and 54. for illustrative purposes, machined into the roll through outer layer 26 and into the fused interface 30 to expose inner layer 28. This machining process will form a series of rings 56, 58 and 60. The axial thickness of the rings is chosen to accommodate the furnace and strip requirements. The machining exposes inner layer 28 which is of a relatively weldable material which may be useful under certain circumstances.
One of the greater advantages of such a structure is illustrated in FIG. 8. A portion of the ringed roll is illustrated on the right. A fragment of a roll 60 made in accordance with my prior invention in which a ring 62 having a relatively insoluble or non-weldable outer layer 64 is centrifugally cast with an inner layer 66 to form a fused interface 68. The ring is then welded at 70 to the body of roll 60 as shown on the left side of FIG. 8.
Referring to FIG. 8, the outside diameter of roll 10 at 72 is greater than the outside diameter of roll 60 at 74 since the inner layer 66 of the ring is the same as the diameter 72 of the unitary roll on the right. Consequently the cross-sectional area of roll 10 can be smaller than roll 60. This design and manufacturing approach can be utilized in many applications with the following limitations:
a) the roll body material selection is slightly more limited with the unitary roll;
b) the high thermal conductivity between the rings and the roll body does not make this an optimum design when cold plates are introduced in hot furnaces, since the heat sink effect of the cold plates on the rings may generate "blistering" separation. Blistering separation is a failure common when using solid rolls in furnaces where cold plates are introduced creating a thermal shock on the roll at the point of contact with the plate. Rolls with welded rings eliminate this type of failure because the ring can shrink independently of the roll body without removing any heat from it.
For illustrative purposes and referring to FIG. 9, the savings using a roll with integral machined rings compared to a roll with welded rings may be determined as follows: ##EQU1## C is Distance to Neutral Axis (in.), I is Moment of Inertia (in. 4 ) with W=CTE (no load change)
C=Do/2
As Do gets larger the difference (Do 2 -Di 2 ) decreases and so the cross-sectional area of the roll reduces the amount of material needed to produce it.
For example, assuming: ##EQU2##
For a 120 inch long roll this would represent approximately 147.0 lbs. savings in material weight and ten fold savings in material cost.
If:
Do.sub.3 =24 in A.sup.3 =19.04 in.sup.2
with nearly 50% savings in material weight. | A method for centrifugally casting a multi-alloy low adhesion furnace roll, includes separately casting each layer and then solidifying the layers when all layers have been cast. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional application of U.S. patent application Ser. No. 12/452,126, filed Apr. 8, 2010, which is the national stage entry of International Patent Application No. PCT/EP2008/055811, filed on May 13, 2008, and claims priority to German Application No. DE 10 2007 029 913.5, filed in the Federal Republic of Germany on Jun. 28, 2007, each of which is expressly incorporated herein in its entirety by reference thereto.
FIELD OF THE INVENTION
[0002] The present invention relates to the use of a control module for a transmission control installed in an automatic transmission.
BACKGROUND OF THE INVENTION
[0003] A control unit known from published German patent document DE 40 23 319 C1 has a printed circuit board substrate in the form of a flexible printed circuit board foil laminated onto a plate. The printed circuit board substrate is equipped on both sides with electrical components which form an electronic circuit. The components are covered by two housing parts placed on the top side and the bottom side, respectively, of the printed circuit board substrate. Outside of the area covered by the printed circuit board substrate covered by the housing parts, a device plug connector part is situated on the printed circuit board substrate which is connected to the components via printed conductors of the printed circuit board substrate and is used for connecting the control unit to an external cable harness. The known control unit is intended to be installed in the engine compartment of a vehicle.
[0004] Moreover, a control unit is known from published German patent document DE 195 28 632 A1 which has a printed circuit board substrate equipped with electrical components which is covered on the top side and the bottom side by housing half-shells. The half-shells are fastened on the printed circuit board substrate using threaded fasteners. A power component situated on the printed circuit board substrate generates heat during operation which is dissipated, via through-contacts underneath the power component, to a heat-conducting layer on the bottom side of the printed circuit board substrate and from there to a housing part which is in contact with it.
[0005] In addition, an electric control unit for a transmission designed as a control module is known from published international patent document WO 2006/066983 in which a device plug connector and a sensor are situated on a substrate whose electrical terminals are connected to a housing interior via a flexible conductor foil and are contacted there, via wire connections, to a circuit part manufactured separately.
SUMMARY OF THE INVENTION
[0006] According to the present invention, the use of a control module for a transmission control installed in an automatic transmission is proposed. The control model is suitable, in a particularly cost-effective and simple manner of manufacturing, for attachment to an automatic transmission. Control units that are installed in automatic transmissions are contacted, besides the unit plug connector and an electronic circuit part of mutually connected electrical components, to a plurality of additional electrical components, such as actuators and/or sensors. The control module provided advantageously has only one single common printed circuit board substrate, and this is a multilayer printed circuit board. The printed circuit traces of the printed circuit board substrate are used not only for the electrical connection of those electrical components which form an electronic circuit part on the printed circuit board substrate that is covered by housing parts, but also for connecting the circuit part to additional electrical components, outside the covered part of the printed circuit board substrate covered by the housing part or, if a plurality of housing parts is provided, outside the part of the printed circuit board substrate covered by the housing parts.
[0007] At least one contact point may be advantageously electrically connected to a sensor connector part which is applied on the printed circuit board substrate. In addition it is possible to provide at least one contact point on the printed circuit board substrate outside the area covered by the housing parts which is electrically connected to an electrohydraulic actuator, an electrically actuatable pressure control valve, for example, or a counter-contact of another transmission component.
[0008] Electrical components, such as a sensor connector part, for example, may advantageously be situated outside of the area of the printed circuit board substrate covered by the housing parts and directly on the printed circuit board substrate. Other contact points on the printed circuit board substrate outside the area covered by the housing parts may be electrically connected to actuators which are situated at a spatial distance from the printed circuit board substrate.
[0009] It is particularly advantageous that the outer areas of the printed circuit board substrate, which are not covered by the at least one housing part, and the device plug connector parts and the at least one contact point are provided with a protective coating. A plate-shaped printed circuit board substrate having a first side, a second side facing away from the first side, and a circumferential front side may advantageously include as the protective coating a coating applied to the first side and the second side and an edge cover applied to the circumferential front side. The protective coating may include a copper layer, a coat of varnish, or another suitable passivating layer which advantageously prevents diffusion of transmission oil, water and other harmful media into the substrate.
[0010] For improving heat dissipation, at least one housing part may be designed to have a plane surface to be placed on a cooling element provided for heat dissipation, in particular a hydraulic plate of a motor vehicle transmission.
[0011] A further improvement of heat dissipation results from the fact that at least one heat generating electrical component, situated on a first side of the printed circuit board substrate, is thermally connected via through-contacts to a heat-conducting layer on a second side of the printed circuit board substrate facing away from the first side. To further improve the heat dissipation, the heat conducting layer is in heat-conducting contact with a housing part and/or a cooling element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows a cross section through an electric control unit according to the present invention, having sensors and actuators situated thereon, mounted on a hydraulic plate of a transmission.
[0013] FIG. 2 shows a top view onto the printed circuit board substrate of the control unit without sensors, actuators or housing parts.
[0014] FIG. 3 shows an enlarged detail from FIG. 1 .
[0015] FIG. 4 shows a detail of a cross section of the printed circuit board substrate, according to another exemplary embodiment of the present invention.
[0016] FIG. 5 shows a cross-section through a further exemplary embodiment of the present invention, the device plug connector part not being depicted for the sake of simplicity.
[0017] FIG. 6 shows a detail of a fourth exemplary embodiment.
[0018] FIG. 7 shows a detail of a fifth exemplary embodiment.
DETAILED DESCRIPTION
[0019] FIG. 1 shows a cross section through a first exemplary embodiment of the present invention. Electric control unit 1 according to the present invention includes a printed circuit board substrate 2 , which may be designed as a single-layer printed circuit board or a multi-layer printed circuit board or as a flexible printed circuit board foil laminated onto a metal plate or as an injection-molded part having printed conductors embedded therein or may be designed in other ways. The printed circuit board substrate has an essentially plate- shaped design having a first side 15 , a second side 16 facing away from the first side, and a circumferential front side 31 . On first side 15 and second side 16 , printed circuit board substrate 2 is provided in a locally limited area with electrical components 11 which form an electronic circuit 9 . Of course, components 11 may also be applied only on one side of the printed circuit board substrate. The area equipped with components 11 is indicated by a dashed line in FIG. 2 .
[0020] Electrical components 11 are electrically connected to one another via printed conductors 12 of printed circuit board substrate 2 . The printed conductors may pass through one or multiple layers of the multi-layer substrate. In addition to printed conductors 12 for wiring components 11 , further printed conductors 13 and printed conductors 14 are situated on the printed circuit board substrate which lead to remote areas of printed circuit board substrate 2 outside the area occupied by electronic circuit 9 on first side 15 and second side 16 . As is apparent in FIG. 2 , the printed circuit board substrate has a maximum length a and a maximum width b which are dimensioned in such a way that as little material waste as possible is created. The surface area of printed circuit board substrate 2 is adapted to the conditions of a motor vehicle transmission. As is apparent in FIG. 1 , components 11 belonging to electronic circuit 9 are covered on first side 15 by a housing part 3 , while components 11 on second side 16 are covered by a second housing part 4 . For example, housing parts 3 , 4 may be designed as metallic half-shell parts, as press-bent parts, for example. As is best apparent in FIG. 3 , first housing part 3 and second housing part 4 may be angled multiple times in the edge area in a known manner, so that a circumferential sealing ring 17 may be placed between the angled area of the respective housing part and printed circuit board substrate 2 . Using screw connections 18 or other suitable means, first housing part 3 and second housing part 4 may be fastened to printed circuit board substrate 2 , the respective circumferential sealing ring 17 being pressed together between the assigned housing part and printed circuit board substrate 2 and electronic circuit 9 being sealed to the outside.
[0021] Printed conductors 14 of printed circuit board substrate 2 connect electrical components 11 to a device plug connector part 6 which is situated outside the area on the printed circuit board substrate covered by housing parts 3 , 4 . Device plug connector part 6 is used to connect control unit 1 to an external cable harness. It is important that outside the area covered by housing parts 3 , 4 and outside the area on printed circuit board substrate 2 covered by device plug connector part 6 at least one contact point 21 is situated which is used for contacting an additional component of the control unit. The at least one contact point 21 may be designed in the form of a metallic surface or a through-contact, for example.
[0022] As is shown in FIG. 1 , the additional component may be a sensor connector part 7 , for example. Sensor connector part 7 is used for a connection to a rotational speed sensor and is electrically connected to two contact points 21 on the printed circuit board substrate with the aid of two contact pins 30 . Contact points 21 are connected to electronic circuit 9 via printed conductors 13 as it is illustrated in FIG. 2 . Sensor connector part 7 may be mechanically fastened to printed circuit board substrate 2 outside the area covered by housing parts 3 , 4 and the device plug connector part. As is also apparent in FIG. 1 , at least one additional contact point 22 is situated on the second side of the printed circuit board substrate which is connected to an electrohydraulic actuator with the aid of an electrically conductive spring contact element 29 . Electrohydraulic actuator 8 may be a pressure control valve which regulates the hydraulic pressure in a hydraulic line of the transmission. Any number of other contact points for contacting electrical components of the transmission, such as sensors, actuators, clamp contacts, and press-on contacts, for example, may be situated on printed circuit board substrate 2 outside the areas covered by housing parts 3 , 4 and device plug connector part 6 . The contact points may be connected to the electrical components with the aid of plug contacts, solder contacts, press-in contacts, spring contacts or other suitable means. All contact points are connected to electronic circuit 9 via printed conductors of the printed circuit board substrate.
[0023] Printed circuit board substrate 2 , equipped with housing parts 3 , 4 , device plug connector part 6 , and contact points 21 , 22 , and possibly electrical components 7 , is mounted on a cooling element 10 via a planar outside surface of second housing part 4 ; the cooling element may be a hydraulic plate of a transmission, for example. Multiple actuators 8 which are electrically connected to assigned contact points 22 on the printed circuit board substrate via spring contact elements 29 are fastened to the hydraulic plate.
[0024] As depicted in FIG. 4 , a frame part 19 filled with a casting compound 20 may be used as a housing part for covering electrical components 11 instead of half-shell-shaped housing part 3 or 4 . But it is also possible to form the housing parts, which cover components 11 , using molding compounds, foams, gels, or other means. It is important that housing parts 3 , 4 protect components 11 on first side 15 and components 11 on second side 16 against aggressive media.
[0025] A particularly preferred exemplary embodiment of the present invention is depicted in FIG. 5 . This exemplary embodiment differs from the exemplary embodiment depicted in FIG. 1 in that the areas on first side 15 and second side 16 of printed circuit board substrate 2 not covered by housing parts 3 , 4 are provided with a protective coating. For this purpose, except for the outer areas occupied by device plug connector part 6 (not depicted), housing parts 3 , 4 , and contact points 21 , 22 , first side 15 and second side 16 of printed circuit board substrate 2 facing away from the first side are each provided with a coating 23 applied over a large area. Coating 23 preferably includes a large-area copper printed circuit board, a coat of varnish, or a suitable hard or soft coating which prevents diffusion of media such as transmission fluid or moist air, for example, into the substrate. An edge cover 24 is applied to the circumferential front side of printed circuit board substrate 2 as the protective coating. Edge cover 24 may be implemented in the form of varnish, molding compounds, extrusion, or another suitable passivation.
[0026] Heat may be dissipated from components 11 , which generate heat, in different ways. As depicted in FIG. 6 , heat generated by power components 11 on first side 15 of printed circuit board substrate 2 may be dissipated to second side 16 in a manner known per se via through-contacts 25 provided in the printed circuit board substrate. Second side 16 of printed circuit board substrate 2 is in thermal contact with a heat-conducting layer 26 . Heat-conducting layer 26 may be a copper layer, for example, which transfers the heat to housing part 4 which is in heat-conducting contact with the copper layer. The heat is dissipated from there to a cooling element 10 , on which housing part 4 rests, and which represents a hydraulic plate of a transmission. The heat may also be transferred directly from heat-conducting layer 26 to cooling element 10 . For this purpose, as depicted in FIG. 7 , the cooling element may be provided with a platform 27 on which printed circuit board substrate 2 rests with heat-conducting layer 26 inserted in between. As depicted in FIG. 8 , cooling element 10 may alternatively have a recess 32 and rim 28 , which encloses recess 32 , on which printed circuit board substrate 2 rests with heat-conducting layer 26 inserted in between. | The use of a control module having at least one housing part and a multi-layer printed circuit board as the electrical connection between the inner space of the housing and components that are situated outside of the housing part is described. The multi-layer printed circuit board is the carrier for the electrical components of an electronic circuit, and is at the same time the thermal contacting to a housing part and/or a cooling element, particularly a hydraulic plate of the transmission, for a transmission control installed in an automatic transmission. |
REFERENCE TO CO-PENDING APPLICATION
This application is a continuation of application Ser. No. 169,281 filed July 16, 1980, now abandoned, which is a continuation-in-part of co-pending applications Ser. No. 706,795, filed July 19, 1976, now abandoned, and of Ser. No. 003,590, filed Jan. 15, 1979, and now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to a chemical process which comprises the production of elemental potassium and the subsequent reaction of said elemental potassium with other reactants, including various metallic ores, such as those of magnesium, lead, zinc, copper, arsenic, antimony or silver to release said metals from their naturally occuring forms, in elemental state, or with water to produce potassium hydroxide and hydrogen and further reacting additional elemental potassium with said potassium hydroxide to produce more hydrogen and a thermally unstable potassium oxide which decomposes into potassium and potassium peroxide or potassium superoxide, optionally reacting said hydrogen and potassium to produce potassium hydride to store the produced hydrogen or to further react said potassium hydride with carbon to produce potassium acetylide and optionally using additional hydrogen to saturate the carbon bonds of these unsaturated compounds, utilizing process potassium or potassium hydride to catalyze the hydrogenation.
OBJECTIONS AND FEATURES OF THE INVENTION
An object of this invention is to provide a low-cost, high-yield process for producing elemental potassium from potassium oxides, or sulfides.
Another object of the invention, is the utilization of process potassium in the manufacture of carbides, acetylides, hydrogen, hydrides, hydrogen peroxide, oxygen, potassium hydroxide, less active metals, saturated and unsaturated hydrocarbons so as to provide the aforementioned products and by-products in one integrated process leading to their manufacture at lower costs than heretofore attainable.
DESCRIPTION OF PRIOR ART DISCLOSURES
There are numerous patents on techniques for producing metals from their salts and for obtaining hydrogen as a by-product. Accordingly, this background disclosure is restricted to those which are believed most relevant.
Very basic is U.S. Pat. No. 2,852,363, which describes a method for preparing potassium, cesium or rubidium by heating a hydroxide of these metals with zinc in an inert atmosphere at a temperature above the boiling point of the particular alkali metal under the pressure used in the reactor and recovering the free alkali metal. While hydrogen also is produced in that process, no suggestion is made about using it.
U.S. Pat. Nos. 1,872,611; 1,034,320; 2,028,390; 3,938,985; and British Pat. No. 590,274 also are pertinent for disclosing processes for the production of alkali metals or alloys thereof.
As will be seen hereinafter, none of these disclose, hint, or suggest in any manner whatsoever applicant's unique, novel and unobvious process.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE accompanying this specification is a diagrammatic representation of one type of apparatus for carrying out the thermal reduction of the present process.
SUMMARY OF THE INVENTION
It has been discovered and forms the substantial conceptual basis of this invention that extraordinary process and product benefits relating to the winning of potassium and other metals and to the formation of organic products with potassium thus obtained can be achieved by the practice of this invention. Relatively low temperatures can be used in the process and high yields achieved therewith. Furthermore, the economics of the process are much improved.
Fundamentally, the invention resides in an integrated progress for producing potassium metal from its non-stoichiometric oxide or sulfide and using this metal to produce less active metals and hydrocarbons by the steps of:
1. thermally decomposing potassium oxide or sulfide substantially in the absence of water into potassium metal and to form, respectively, potassium peroxide or potassium superoxide, and potassium disulfide; and recovering the potassium metal;
2. providing a portion of the thus formed potassium in the molten or vapor state and reacting same with at least one oxide or sulfide of magnesium, copper, calcium, silver, lead, zinc, antimony, cadmium, iron, arsenic and mixtures thereof to displace the metal from said oxide or sulfide followed by recovery of said metal;
3. reacting another portion of the previously obtained potassium with water to form hydrogen and potassium oxide;
4. utilizing the previously formed hydrogen to prepare an organic compound by either:
(a) reacting said hydrogen with potassium obtained by step 1, above, at a temperature of between 250° and 300° C. to form potassium hydride, reacting said potassium hydride with carbon to form potassium acetylide and reacting said acetylide with water to produce acetylene and KOH; then hydrogenating said acetylene to form ethane and ethene; or,
(b) using said hydrogen to hydrogenate carbon in the presence of a catalyst to form methane.
The organic compounds, ethane or methane, can be reacted with a halogen in manner known per se to form an alkyl halide which can then be condensed with sodium or process potassium to form hydrocarbons boiling in the fuel range under Wurtz-Fitig reaction conditions.
In subsidiary reactions, intermediate compounds are formed and recycled to produce additional potassium for reuse in the process.
DESCRIPTION OF PREFERRED EMBODIMENTS
The process of the invention comprises the following equations: ##EQU1##
11. K+R a Y b →K x Y x +R. This reaction is carried out with molten potassium, at temperatures above 65° C. or with potassium vapor at temperatures above 780° C. Y is either sulfur or oxygen and R is magnesium, zinc, cadmium, lead, iron, arsenic, antimony or silver or copper.
12. C 2 H 5 X+C 2 H 5 X+2 K=C 4 H 10 +2 KX, wherein X is chlorine or bromine. ##EQU2##
16. K 2 S 3 →K 2 S+k 2 S 2 at 1/2 mm Hg pressure at 360° C.
17. K 2 S+H 2 O→KOH+KHS Additional water gives a reversible reactions KHS+H 2 O→KOH+H 2 S
18. Beginning 315° C. H 2 S→H 2 +S
19. 4 K 2 S 2 +8 H 2 O→3K 2 S+X.H 2 O+K 2 S 5 (in a closed system).
20. 4 K 2 S 3 +X H 2 O→2 K 2 S 5 +2K 2 S.X.H 2 O. The minimum amount of water (X) is that required to form the hydrate of potassium sulfide which exists at the temperature at which this hydrolysis occurs.
21. 4 K 2 S 4 +X H 2 O→3 K 2 S 5 +K 2 S.X H 2 O.
All of these hydrolysis decomposition reactions are carried out in a closed system and at temperatures above 60° C. and below the critical temperature of water. The minimum amount of water (x) required for these hydrolysis reactions is that which constitutes the hydrate of potassium sulfide which exists at the selected temperature or below 206° C., the melting point of K 2 S 5 .
The process of this invention utilizes the lack of thermal stability of the non-stoichiometric sulfide and oxide compounds of potassium, to produce elemental potassium and a variety of potassium compounds, thereafter utilizing this elemental potassium or some of the potassium compounds to continually reform these sulfides and oxides of potassium by reaction with water, metallic ores, etc.
Referring to the above equations: Equations 1, 4 and 14, are the basic equations of this invention, whereby elemental potassium is formed by thermal decomposition of potassium sulfide into potassium disulfide and said elemental potassium and the decomposition of potassium oxide into elemental potassium and potassium peroxide or potassium superoxide.
Equation No. 15 illustrates the decomposition of potassium disulfide into potassium sulfide and sulfur, while equation No. 16 illustrates the decomposition of potassium trisulfide, or higher polysulfide, into potassium sulfide and potassium disulfide. Equations No. 19, 20 and 21, illustrates the hot water hydrolysis of potassium polysulfide into potassium sulfide hydrate and potassium pentasulfide. The heat-reduced pressure decomposition of potassium trisulfide as illustrated in equation No. 16 are equally applicable to potassium tetrasulfide, potassium pentasulfide and potassium hexasulfide. Equation No. 6, 9 and 9a illustrate the decomposition of potassium peroxide and potassium superoxide. Potassium peroxide is decomposed into elemental potassium and elemental oxygen. Potassium superoxide (KO 2 ) is decomposed into potassium peroxide K 2 O 2 and oxygen. At temperatures above 780° C., K 2 O 2 begins to decompose to K and O 2 .
Potassium does not unite with oxygen or sulfur in the absence of water vapor. Removal of water vapor from the process system will greatly reduce the tendency of potassium and either sulfur or oxygen to reunite following the thermal reduced pressure decomposition of potassium oxide or potassium sulfide.
Potassium hydroxide, potassium oxides, potassium sulfides and potassium hydrosulfides are deliquescent and have low aqueous tensions. Potassium sulfides and potassium oxides are non-stoichiometric compounds with deficiencies in the anion sub-lattice. Water, hydrogen, and even potassium hydride will substitute in the anion sub-lattice. The hydrogen is produced by the reaction of potassium metal with water vapor and the reaction with elemental potassium to produce potassium hydroxide and hydrogen. Additional potassium will react with this potassium hydroxide to form additional hydrogen and potassium oxide. In the case of the potassium oxides, water will also react directly with potassium oxide to form potassium hydroxide. At the beginning of the thermal decomposition of the potassium sulfides or oxides, the elemental potassium will react with this potassium hydroxide to form additional hydrogen and potassium oxides. At the 350° C. decomposition temperature of potassium oxide, the elemental potassium will unite with some of the hydrogen produced and form potassium hydride. As the temperature is elevated to above 380° C., potassium hydride begins to dissociate.
The elemental potassium, produced from the decomposition of potassium sulfide or potassium oxide, is soluble in the solids remaining until temperature-pressure conditions above those necessary to boil elemental potassium are reached. As shown by Equations 15-21, I have observed that potassium sulfide, prepared by the reduction of the sulfur content of potassium pentasulfide or any polysulfide with a sulfur content of two or greater, can be decomposed to elemental potassium and sulfur at 780° C. in a twenty-four hour period. Potassium pentasulfide melts at 206° C. and decomposes to potassium tetrasulfide and sulfur at temperatures beginning at 300° C. At 206° C., potassium pentasulfide melts are essentially anhydrous. Potassium tetrasulfide melts at 145° C., Potassium trisulfide melts at 279° C. and potassium disulfide melts at 470° C. Any of these compounds produce an anhydrous melt at temperatures above their melting points. It is easier to form these anhydrous melts under reduced pressure. The reduced pressures allow the water of hydration to be removed more easily to form anhydrous melts. The temperature should be at least as high as the melting point of the particular potassium polysulfide and the reduced pressures should be residual pressures of from 1 mm Hg to 50 mm Hg. As these potassium polysulfides are decomposed into lower sulfur content polysulfides, the temperature-reduced pressure conditions should be adequate to distill the sulfur. Sulfur boils at 445° C. at 760 mm Hg pressure, at 185° C. at 1 mm Hg pressure.
Potassium trisulfide decomposes to a mixture of potassium monosulfide and disulfide at 350° C. at 0.05 Torr. Potassium disulfide decomposes to potassium sulfide and sulfur at 650° C. at 0.05 Torr and anhydrous potassium sulfide decomposes to elemental potassium and sulfur at 780° C. while hydrated potassium sulfide requires 840° C. to decompose to sulfur and potassium. Without reduced pressures, potassium disulfide is the most stable union of potassium and sulfur thermally, with potassium sulfide decomposing to elemental potassium and potassium disulfide at temperatures above 780° C. for anhydrous potassium sulfide or 840° C. for hydrated potassium sulfide.
For practical purposes, the decomposition of potassium disulfide occurs at 883° C. at 10 mm Hg pressure. At this temperature pressure, potassium disulfide is rapidly decomposed into its elements. The alternate source of potassium from potassium sulfides is the decomposition of potassium disulfide into potassium sulfide at reduced pressures of 1 mm Hg at 78° C. and the subsequent decomposition of potassium sulfide into its elements under the same conditions.
Where the present process starts with potassium oxide, potassium monoxide is decomposed into elemental potassium and potassium peroxide or potassium super oxide at temperatures above 350° C., however, the potassium is not readily available for extraction from this mixture, at these temperature. At pressures of 5×10 -4 at 360° C. some elemental potassium can be extracted by distillation. At temperatures above the melting point of potassium peroxide, 490° C., potassium can be extracted by distillation at pressures 10 mm Hg. At temperatures of 780° C., almost all of the potassium can be extracted by distillation at 10 mm Hg. The elemental potassium decomposes into potassium peroxide and potassium and the potassium peroxide is then melted at 490° C. to make the mix anhydrous. By the removal of the water the formation of hydrides, hydroxides and hydrogen is retarded and this allows the decomposition of the potassium oxides into their elements of formation.
The potassium, produced by the present invention, is then reacted with an amount of water less than the stoichiometric amount, such as 15% less than stoichiometric, to produce potassium hydroxide and hydrogen, as shown in equation 2a. Additional potassium and the potassium hydroxide at temperatures above 360° C. will produce additional hydrogen and form the unstable potassium monoxide (equation 2). The potassium monoxide K 2 O is then decomposed to potassium and oxygen or potassium and potassium peroxide or potassium superoxide by one of the processes disclosed, to continuously produced hydrogen (Equation 4). A part of the potassium peroxide or potassium superoxide can be dissolved in an amount of water less than the stoichiometric amount, such as 15% less than stoichiometric to produce additional potassium hydroxide and hydrogen peroxide (Equation 10). The unstable hydrogen peroxide can then be used as a source of oxygen. Potassium superoxide and potassium peroxide can also be used as sources of oxygen at temperatures above 653° C. for the superoxide or above 780° C. for the peroxide, as shown by Equation 9 and 9A.
At any temperature above its melting point, 65° C., potassium in liquid or vapor form will reduce the ores of magnesium, copper, silver, lead, zinc, antimony, arsenic, cadmium, and mixtures thereof to the free metal and form potassium oxide or form either the sulfides or oxides of potassium by the liberation of elemental copper, silver, lead, zinc, calcium, antimony, arsenic, cadmium, etc. depending upon whether these metals were in oxide or sulfide form in their naturally occurring mixed ores or ore concentrate.
When elemental potassium has been used to form hydrogen by the decomposition of water or potassium hydroxide or by the reduction of hydrogen sulfide, derived from the decomposition of the hydrolysis product, potassium hydrosulfide, from potassium sulfide, this hydrogen may be stored as potassium hydride by reaction of said hydrogen with additional elemental potassium at temperatures between 250° C. and 360° C. Potassium hydride is miscible in molten potassium.
Potassium hydride dissolved in molten potassium reacts directly with carbon and graphite to produce potassium acetylide. Potassium acetylide reacts with water to produce acetylene.
The acetylene produced can be reacted with additional process hydrogen, utilizing molten potassium or potassium hydride as the catalyst to form ethene or ethane. The amount of hydrogen present will determine the formation of ethene or ethane. The temperature of this reaction is any temperature above the melting point of potassium, 65° C.
Hydrogen produced in the present invention can be directly combined with carbon to form methane in the presence of a suitable catalyst such as nickel at temperatures of 250° C. by the Raney-Nickel method. Elemental potassium or potassium hydride dissolved in potassium may be used as the catalyst at temperatures between 180° C. and 360° C.
EXAMPLE I
This example illustrates the preparation of potassium metal from K 2 O present in an ore.
In conducting this example, an ore containing 10 kg of K 2 O was placed in an autoclave and heated to 883° C. under a reduced pressure of 10 mm of Hg. 4.1 kg of potassium metal was distilled, leaving behind 5.9 kg of K 2 O 2 .
EXAMPLE II
This example illustrates the reactions of Equations 2-9, 11-12.
Technical grade flakes of potassium hydroxide of 90% purity were heated to 380° C. A reduced pressure of 50 mm Hg was used to dehydrate said flakes during the making of an essentially anhydrous melt.
Thereafter, the use of reduced pressures was discontinued and with the temperature maintained at 380° C., elemental potassium was added to the melt. Hydrogen was evolved. The stoichiometry was one mole of potassium hydroxide, derived from 62.2 grams of 90% technical flakes of KOH, and one mole (39.1 g) of elemental potassium.
The hydrogen evolved was passed into molten potassium maintained at 280° C. to form potassium hydride. One and one-half moles of potassium were used to take up the one mole of hydrogen and to form a liquid consisting of a solution of potassium hydride in molten potassium.
The potassium hydride solution containing one mole of KH in molten potassium was treated at 350° C. in the absence of air, nitrogen, or carbon dioxide with two moles of carbon (graphite) to form potassium acetylide.
The mixture was carefully and slowly added to one and a half mole of water to form one mole of acetylene and hydrogen as volatiles and form a solution of potassium hydroxide. The gases produced, hydrogen and acetylene, occupied 3.2 liters at 15° C. at atmospheric pressure, indicating conversion to one mole of acetylene and one-half mole of hydrogen.
The potassium oxide, formed by the reaction of potassium and potassium hydroxide, was heated to 500° C. under a reduced pressure of 10 mm Hg. After two hours of being maintained at 500° C. under 10 mm Hg., the mixture was heated to 883° C. and one and one half moles of potassium were condensed by selectively cooling the emitting gas stream in three hours and twenty minutes.
EXAMPLE III
One mole of potassium produced in Example I was treated with water as shown in Equation 2A to provide additional hydrogen gas and potassium hydroxide.
One mole of potassium superoxide produced in Example VI was added to two moles of water at 95° C. to produce one mole of hydrogen peroxide and two moles of potassium hydroxide, as illustrated by Equation 10.
This example thus shows the recovery of nearly all the potassium in the forms originally used; i.e. elemental potassium and potassium hydroxide.
EXAMPLE IV
This example shows the thermal decomposition of K 2 S into potassium, as shown by Equation 14.
Two pounds of K 2 S were heated to 780° C. under a pressure of 50 mm to remove water. The pressure was then reduced to 5×10 -4 at that temperature.
Sulphur was distilled and condensed in a liquid nitrogen series of traps.
When the distillation rate of sulfur decreased, the temperature was elevated to 883° C. The distillation chamber was left with potassium sulfate, identified by the barium analytical reaction, with the potassium and sulfur condensed in fresh traps cooled by liquid nitrogen. The potassium and the sulfur did not reunite in the absence of water vapor.
200 grams of potassium were collected.
EXAMPLE V
As per Equation 11, the potassium produced in Example IV was melted under 50 mm of Hg pressure and decanted from the sulfur.
The potassium was divided into four fifty gram samples and was used in its molten form.
One fifty gram sample was used to smelt 54 grams of a lead sulfide concentrate containing 73% lead. The smelting was done at 70° C. After the reaction had ceased (in approximately three minutes) the temperature was elevated to 330° C. and the molten lead was tapped from the lighter material floating on the lead surface.
One fifty gram sample was used to smelt 41.6 grams of zinc sulfide concentrate, containing 50% zinc. The temperature was 70° C. The reaction required approximately two minutes. The temperature was elevated to 440° C. and the liquid molten zinc was tapped from below the material floating on the surface of the zinc.
One fifty gram sample was used to smelt 50 grams of a copper sulfide concentrate containing 86% chalcopyrite (CuFeS 2 ). The reaction was carried out at 70° C. Iron and copper were produced. The iron was magnetically separated from the copper. The copper was melted and separated from the material floating on the copper surface.
One fifty gram sample was used to smelt 25 grams of magnesium oxide at 360° C. The reaction required six minutes. Elemental magnesium was produced.
In all of these samples, the residual potassium was distilled from the metals produced at pressures adequate to distill potassium but too low to volatilize the other metal. The three sulfide samples were separated from their carrying and largely inert gangue by dissolving the potassium sulfides produced in this smelting operation in small quantities of water. The solids were then separated from the liquid by filtration.
Sulfur was added to the filtrate and the filtrate were dehydrated at 500° C. under 50 mm Hg. pressure. The resulting anhydrous melt was then subjected to temperatures of 883° C. under 10 mm pressure to reform potassium vapor and sulfur vapor which were then condensed. This reformation of the potassium completed the cycle.
The potassium oxide produced in the magnesium smelting was directly recycled to potassium by heating the gangue and the potassium oxide to 883° C. under 10 mm Hg. Some carbon dioxide was distilled prior to the distillation of the potassium. The carbon dioxide was taken up in potassium hydroxide as it emitted the system. The potassium was largely recovered after the carbon dioxide had been removed from the system. A second sample showed that the carbon dioxide could be removed by pre-heating the magnesium oxide under reduced pressures prior to reacting same with potassium. The potassium produced by the recycling of the potassium oxides was condensed by cooling and used to smelt additional magnesium ore.
EXAMPLE VI
This example illustrates the reactions of Equation 4,5, 9-10 and 13.
Hydrogen, produced by this invention, was used to hydrogenate carbon, (graphite) at 250° C. in the presence of molten potassium (potassium hydride dissolved in molten potassium (Raney-Nickel, also can be used). No pressures were used other than the pressure of the hydrogen issuing from the process system. A total of 100 grams of carbon was hydrogenated to methane in one-half hour by the use of one mole of potassium and one mole of potassium hydroxide by continually recycling these reagents. This recycling consisted of dissolving residual potassium oxides in water and then reacting this potassium hydroxide with potassium produced by the thermal decomposition of potassium oxides at 883° C. under 10 mm Hg (Equation 1 and 2).
A step to reduce the oxygen content of the system by decomposing any potassium superoxide that might be produced was carried out by heating the potassium oxides to 653° C. prior to decomposition at 883° C. Care was taken to condense potassium and allow the oxygen to escape the process system. This was done to avoid the production of potassium carbonyl.
The undecomposed residue was used to form potassium hydroxide and to form hydrogen peroxide by reaction with water (Equation 10). Care was taken not to allow hydrogen peroxide or any oxygen arising from the decomposition of hydrogen peroxide to enter the smelting system.
EXAMPLE VII
This example shows the production of elemental potassium and a mixture of potassium peroxide and potassium superoxide by thermal decomposition of potassium oxide; next reacting potassium peroxide and superoxide with a stoichiometric quantity of water to form potassium hydroxide and oxygen; then reacting elemental potassium with potassium hydroxide to form elemental hydrogen and to reconstitute potassium oxide for recycling.
This decomposition can be practiced in the 360° C.-380° C. temperature range with appropriate addition and withdrawal of product, over or at a temperature range below 653° C. or at a temperature of over 779° C.
In conducting this run, potassium hydroxide is heated to 370° C. in the absence of air under a reduced pressure of 1-10 MM Hg. Elemental molten potassium is slowly added to a potassium hydroxide anhydrous melt, in a 1 mole to 1 mole stoichiometric ratio. Elemental hydrogen is evolved and substantially increases the pressure within the system. Potassium will react with oxygen, nitrogen, carbon dioxide, etc. Therefore, the use of reduced pressure is necessary to reduce the reaction between molten potassium and the inert atmosphere. Neon, helium, argon, (group 8 gases) can be used in lieu of reduced pressure.
The system is opened, hydrogen is allowed to exit the process system and collected. Following the removal of the hydrogen, the reduced pressure is again employed. The potassium oxide formed during the evolution of hydrogen, is decomposed, principally by thermal means alone. The elemental potassium formed along with potassium peroxide and potassium superoxide (K 2 O 2 ) is gradually distilled prior to the thermal-reduced pressure decomposition of potassium peroxide. Only the potassium is distilled. The distilled liquid/gas potassium and the hydrogen are converted into potassium hydride at temperatures below 380° C. under atmospheric pressure or super-atmospheric pressure.
Following removal and separation of hydrogen and potassium, an amount of water less than the stoichiometric amount, such as 15% less than stoichiometric potassium peroxide (KO 2 ) to form potassium hydroxide and oxygen. This oxygen is separately removed from the process system. The hydrogen, potassium are separated from the process system separately from the oxygen removed.
The surplus of elemental potassium removed from the system above that predicted from the formation of potassium peroxide KO 2 indicates that some potassium superoxide K 2 O 2 has been formed.
The potassium and the potassium hydride are again reacted with water to form additional hydrogen.
1 M (56.11 Grams) of potassium hydroxide (85-86% purity) was brought to 380° C. under 10 MM pressure. Water was distilled as progressively lower potassium hydroxide hydrates were formed. A solid potassium hydroxide then melts at 360° C.±5° C. One mole elemental potassium was melted under an argon atmosphere and added drop by drop to the melt of potassium hydroxide.
When the evolution of hydrogen increased the pressure of the evacuated system to atmospheric or super-atmospheric pressure, the system is opened and hydrogen is exited from the system. When the hydrogen has been removed, as evidenced by the stabilizing of system pressure at slightly above atmospheric reduced pressure is again used preferably at approximately 1 MM Hg. Elemental potassium is distilled from the system. Slightly over one mole of potassium is distilled.
The elemental potassium is reacted with the hydrogen at temperatures between 260° C.-380° C. to form solid potassium hydride. Potassium hydride is soluble is excess molten potassium.
Slightly less than 1 M of water is added to the mix. The amount of water is reduced below 1 M by the same ratio that excess potassium had been removed from the system, to the potassium peroxide-superoxide remaining in the reaction vessel. Oxygen is evolved and potassium hydroxide is formed.
EXAMPLE VIII
This example shows the high temperature production of hydrogen. In conducting this run, one mole of commercial potassium hydroxide is heated to 779° C. under reduced pressure or under an inert gas atmosphere (helium, neon, argon, etc.).
Water is removed as the series of potassium hydroxide hydrates contained therein is decomposed to lower hydrates with the rise in temperature. At 360° C.±5° C., potassium hydroxide forms an anhydrous melt.
Additional water, above that of the hydrates, is given off by the partial thermal decomposition of potassium hydroxide to potassium oxide and water. Above 360° C.±5° C., there is a progressive decomposition of potassium oxide to potassium peroxide and elemental potassium.
The potassium thus produced reacts with the water vapor to form potassium hydroxide and water and with potassium hydroxide to form hydrogen and potassium oxide (Equations 20 and 21).
An equilibrium is reached when approximately 13% of the potassium and hydrogen have been distilled. Thereafter the decrease of the hydrogen content of the process system allows further decomposition of the potassium hydroxide-potassium oxide-potassium peroxide to potassium without recombining of potassium with oxygen due to the diminished water content of the system.
88% of the potassium is recovered in 21/2 hours and about 88% of the hydrogen is also recovered.
The reaction time is accelerated to 1 hour by the addition of 1/2 Mole of potassium to the anhydrous melt of potassium hydroxide.
EXAMPLE IX
One mole of hydrogen produced as above indicated was reacted with the acetylene produced at 360° C. to form ethene. A second mole of hydrogen was supplied to hydrogenate the ethene to ethane.
One mole of ethane was reacted in the gaseous phase with one mole of chlorine to form ethyl chloride. The ethyl chloride was collected and reacted with potassium by refluxing in absolute ether under Wurtz-Fittig Reaction conditions to form butane. The butane thus produced was reacted in the same manner with chlorine gas to form butyl chloride which in turn was reacted with potassium metal produced as above indicated also under Wurtz-Fitting Reaction conditions to form hydrocarbons having octane ratings suitable for use in internal combustion engines.
Suitable apparatus for carrying out the present process as shown in the drawing comprises a melting chamber or retort 10 made of corrosion resistant metal or alloy such as nickel or tungsten metal which can be heated under reduced pressure. A tap 12 for molten metal is formed or secured at the bottom of the chamber. A vacuum line 14 connects the chamber to a pump (not shown) capable of exhausting the chamber to a pressure of 1/2 to 26 mm Hg. pressure. Connected between the chamber and the vacuum line 14 are three traps A,B,C, for condensing and returning reformed oxides or sulfides and elemental condensed alkali metal to chamber 10 through stopcocks 16. A fourth trap 18 is provided remote from melting chamber 10 for collection of sulfur which can be removed through outlet 20. Suitable means (not shown) are provided on or around the melting chamber 10 to heat it up to 680° C. and the areas remote from the chamber to gradually decreasing temperatures of 450° C. to 160° C.
A ring 21 fitted within slot 22 is provided on the metal chamber 10 to pick up metal from condensed vapors passing through the vacuum line 14.
It is to be understood that the foregoing specific examples are presented by way of illustration and explanation only and that the invention is not limited by the details of such examples.
The foregoing is believed to so disclose the present invention that those skilled in the art to which it appertains can, by applying thereto current knowledge, readily modify it for various application. Therefore, such modifications are intended to fall within the range of equivalence of the appended claims. | Disclosed is a combinative integrated chemical process using inorganic reactants and yielding, if desired, organic products. The process involves first the production of elemental potassium by the thermal or thermal-reduced pressure decomposition of potassium oxide or potassium sulfide and distillation of the potassium. This elemental potassium is then used to reduce ores or ore concentrates of copper, zinc, lead, magnesium, cadmium, iron, arsenic, antimony or silver to yield one or more of these less active metals in elemental form. Process potassium can also be used to produce hydrogen by reaction with water or potassium hydroxide. This hydrogen is reacted with potassium to produce potassium hydride. Heating the latter with carbon produces potassium acetylide which forms acetylene when treated with water. Acetylene is hydrogenated to ethene or ethane with process hydrogen. Using Wurtz-Fittig reaction conditions, the ethane can be upgraded to a mixture of hydrocarbons boiling in the fuel range. |
TECHNICAL FIELD
This invention relates to the integration of computer graphics and video to provide a realistic three dimensional virtual reality experience.
BACKGROUND OF THE INVENTION
The display of a three dimensional world to a viewer requires considerable computation power, and it is typically costly to develop the necessary highly detailed models required for doing so. In order to simplify the problem, a portion of the world that is in the distance may be represented in only two dimensions as a video displayed on a surface, e.g., a screen. By video it is meant the common usage of the term, such as the placing or projecting of predefined images on the surface, e.g., the electronic version of filmed moving pictures. Thus, such a world is essentially truncated in length to the screen on which the video is displayed. A great reduction in computation power and cost can be achieved by such an arrangement.
SUMMARY OF THE INVENTION
We have recognized that a limitation of such a world occurs when an object within the field represented by the video undergoes a trajectory that takes it to a location in the world that is not represented by the video on the video screen as currently configured, i.e., shaped and sized, but instead is a location which is represented by computer graphics, namely, that any portion of the object that is no longer on the video screen disappears. More specifically, the object disappears as it exits the screen. Therefore, in accordance with the principles of the invention, when an object within the field represented by the video undergoes a trajectory that takes it, or a portion thereof, to a location in the world that is not represented by the video but instead is a location which is currently represented by computer graphics, the configuration of the screen is changed so that the object can continue to be displayed as video. In accordance with one aspect of the invention, the size and/or shape of the video screen is changed. For example, the video screen may be increased in overall size, or it may “grow” a specific appendage screen on which the object is displayed as video. In accordance with another aspect of the invention, if an additional appendage screen is “grown”, it need not be contiguous with the screen as previously configured. Such appendage screens may be sized, shaped, and located so that the video object continues to be visible, e.g., in front of, or to the side of, the previous shape of the video screen, rather than becoming invisible because it is no longer displayable within the video screen.
BRIEF DESCRIPTION OF THE DRAWING
The file of this patent contains at least one drawing executed in color. Copies of this patent with color drawing(s) will be provided by the Patent and Trademark Office upon request and payment of the necessary fee.
In the drawing:
FIGS. 1-5 show an example of that which a user sees according to the invention when an object, that is displayed as video on a video screen of a world that has a portion of the world distant from the point of view of the user represented in only two dimensions as a video on the video screen, undergoes a trajectory that takes at least a portion of it to a location in the world that is not represented by the video but instead is a location in the world that is represented by computer graphics, and such an object or portion is made to yet be visible to the user by changing the configuration of the screen so that the object can continue to be displayed as video;
FIGS. 6 and 7 show possible side views of the world shown in FIG. 5;
FIG. 8 shows an exemplary process by which a video screen is modified so that any object within the field represented by the video surface that, due to its projected motion is to be displayed in the three dimensional world, e.g., in front of, to the side of, above, or below, the video surface, will, as a result of the modification, continue to be displayed as video on a newly-formed or reshaped extension to the original video screen in accordance with the principles of the invention; and
FIG. 9 shows additional details for performing the screen modifications called for in one of the steps of FIG. 8 .
DETAILED DESCRIPTION
The following merely illustrates the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.
Thus, for example, it will be appreciated by those skilled in the art that the block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the invention. Similarly, it will be appreciated that the various flow charts, flow diagrams, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.
The functions of the various elements shown in the FIGs., including functional blocks labeled as “processors” may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, read-only memory (ROM) for storing software, random access memory (RAM), and non-volatile storage. Other hardware, conventional and/or custom, may also be included. Similarly, any switches shown in the FIGS. are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the implementor as more specifically understood from the context.
In the claims hereof any element expressed as a means for performing a specified function is intended to encompass any way of performing that function including, for example, a) a combination of circuit elements which performs that function or b) software in any form, including, therefore, firmware, microcode or the like, combined with appropriate circuitry for executing that software to perform the function. The invention as defined by such claims resides in the fact that the functionalities provided by the various recited means are combined and brought together in the manner which the claims call for. Applicant thus regards any means which can provide those functionalities as equivalent as those shown herein.
To better illustrate the invention, FIGS. 1-5 show an exemplary virtual world that is represented in multiple portions. One portion of the world is relatively distant from the point of view of the user and is represented in only two dimensions as a video on a video screen. The other portion of the world is relatively close to the point of view of the user and is not represented by video but instead is represented by computer graphics. Each of FIGS. 1-5 is a different view of the virtual world which is designed to help show that which a user sees according to the invention when an object, that is displayed as video on the video screen undergoes a trajectory that takes at least a portion of it to a location in the computer graphics portion of the virtual world, and such an object or portion is made to yet be visible to the user by changing the configuration of the screen so that the object can continue to be displayed as video. For simplification of terminology purposes, a portion of an object may simply be referred to as an object, since any portion of an object may be considered an object in its own right.
FIG. 1 shows world 101 , which is the Champs Elysees in Paris, France, as one approaches La Place de l'Etoile in the center of which is the Arc de Triomphe. World 101 is divided into two portions, video screen 103 , on which is shown the current frame of a video and the remainder of the world 105 , which is represented using computer graphics techniques, and is thus referred to herein as computer graphics part (CG Part) 105 . The current frame of video being displayed on video screen 103 includes police van 113 and Arc de Triumph 115 . Within CG Part 105 there are various elements, such as bicyclist 107 , representing the user, road 109 , and sky 111 .
Note that the viewpoint of the user is actually behind the representation of the user in the form of bicyclist 107 . Also note that police van 113 , which is part of the current video frame being shown on video screen 103 , is moving slower than bicyclist 107 , so that police van 113 will eventually be passed by bicyclist 107 as he continues to ride toward Arc de Triumph 115 .
FIG. 2 shows world 101 of FIG. 1, but at a later time. At the time of FIG. 2, the frame of video being shown on screen 103 is from a view closer to Arc de Triumph 115 . Such a frame may have resulted, for example, from moving the camera that captured the video closer to Arc de Triumph 115 . As a result of the camera location when the frame of video on screen 103 that is shown in FIG. 2 was taken, only a portion of police van 113 was captured video frame. The rest of the police van 113 was out of view of the camera, and hence is not visible within the current frame of video on screen 103 that is shown in FIG. 2 . However, from the viewpoint of the user, looking at world 101 as it appears in FIG. 2, the remaining portion of police van 113 should be visible, notwithstanding that it is no longer within the boundaries of video screen 103 . Thus, the problem of the prior art is clearly seen.
To avoid this problem, in accordance with the principles of the invention, the remaining portion of police van 113 is displayed by reconfiguring video screen 103 so that the entire police van 113 may be displayed thereon as video. This is shown in FIG. 3 . More specifically, FIG. 3 shows the same view as in FIG. 2, but video screen 103 has been reconfigured to be larger than it was previously. Onto enlarged video screen 103 is projected the video information that was not previously projected onto video screen 103 . In particular video of the entire police van 113 is now projected onto video screen 103 . The additional information that is projected onto video screen 103 in this embodiment may have been originally taken as part of the video when it was originally filmed but the video was cropped to fit on video screen 103 , for any number of reasons, e.g., to reduce transmission bandwidth or to increase the size of CG part 105 . Alternatively, the additional video information may be retrieved or developed when needed, based on the video information available in, or in association with, the current frame and/or other frames of the video.
FIG. 4 . shows another embodiment of the invention. In FIG. 4 is shown essentially the same view as in FIG. 2, but an appendage screen 403 is grown from video screen 103 . In other words, the size of the “main” portion of video screen 103 in FIG. 2 is the same as in FIG. 2 but there is added to the formerly rectangular screen 103 further screen area in the form of appendage screen 403 . Video of the police van 113 is projected onto appendage screen 403 . Note that some or all of police van 113 may be projected onto appendage screen 403 , as may be any other necessary background or foreground information that is included in the video. The additional information that is projected onto appendage screen 403 , in this embodiment may have been originally taken as part of the video when it was originally filmed but the video was cropped to fit on video screen 103 before growing appendage screen 403 , for reasons such as described above. Alternatively, the additional video information may have been developed later, based on the video information available in, or in association with, the current frame and/or other frames of the video. Also note that the appendage screen may be any shape and need not be rectangular.
FIG. 5 shows world 101 of FIG. 1, but at a time even later than that of FIG. 4 . Thus, at the time of FIG. 5, the frame of video being shown on screen 103 is from a view still closer to Arc de Triumph 115 than that of FIG. 4 . As a result of the camera location when the frame of video on screen 103 that is shown in FIG. 5 was taken, none of police van 113 is visible within the current frame of video on screen 103 as configured in FIGS. 1 or 2 . However, from the viewpoint of the user, looking at world 101 as it appears in FIG. 5, police van 113 should be visible to the user's left, notwithstanding that it is no longer within the boundaries of video screen 103 . Therefore, in accordance with the principles of the invention, police van 113 is displayed as video on appendage screen 503 which is a portion of main video screen 103 but which is detached therefrom. In a typical embodiment of the invention, at least a portion of police van 113 will continue to be displayed as video on appendage screen 503 until police van 113 passes completely from the user's viewpoint. Note that appendage screen 503 may be changed in size, and the frame of video displayed thereon transformed in size, location and orientation, so as to better realistically display police van 113 .
FIG. 6 shows one possible side view of world 101 as shown in FIG. 5 . This view, which is essentially only for pedagogical purposes, demonstrates that video screen 103 and appendage screen 503 may be substantially coplanar. On the other hand, video screen 103 and appendage screen 503 need not be substantially coplanar, and a possible side view of world 101 as shown in FIG. 5 where video screen 103 and appendage screen 503 are not substantially coplanar is shown in FIG. 7
Note that the techniques of the invention as shown in FIGS. 3 through 7 may be combined, as necessary and appropriate, for any frame.
FIG. 8 shows an exemplary process by which a video screen is modified so that any object within the field represented by the video surface that, due to its projected motion is to be displayed in the three dimensional world, e.g., in front of, to the side of, above, or below, the video surface, will, as a result of the modification, continue to be displayed as video on a newly-formed or reshaped extension to the original video screen, in accordance with the principles of the invention. In typical embodiments of the invention, the objects to be monitored, and their location in the video and the time associated with their position within the video is known, so that the time and extent of the screen modifications are known. However, the techniques of the invention may be employed with computers and software that are sufficiently sophisticated to track recognizable objects within the video surface and to modify the configuration of the video surface in response to the movements of these objects.
The process is entered in step 801 when the user selects a particular world to view and the first frame of the video therefor is to be displayed to a user. In step 803 , the video frame to be displayed is retrieved. This may be achieved by retrieving data representing the frame that is pointed to by a pointer. Such a frame pointer is set initially, e.g., in step 801 , to point to the first frame of the video. Next, in step 805 , it is determined if there are any objects within the current video frame that are to be displayed on the video screen for which screen modifications need to be performed. As noted, this may be achieved by employing additional information associated with the frame that describes any objects that need to be monitored. Such additional information may also include data necessary to modify the video screen. Alternatively, this step may be achieved by analyzing the content of the video frame, perhaps in conjunction with prior frames and future frames, to determine data necessary to monitor the object as well as data that determines how to modify the video screen. In addition, the viewpoint given to the user by the overall display may be incorporated in the determination. Such a viewpoint is determined by camera controls, which may be set by the user. Of course, a combination of the foregoing techniques may also be employed. In step 807 , a computer graphics display engine routine is initiated for performing the modifications determined in step 805 .
The video frame is displayed in step 809 . In step 811 the next video frame is advanced to, provided that there is one. This may be achieved by incrementing or otherwise updating the value of the frame pointer. Of course, the next video frame could also be a previous frame, for example, if the bicyclist allowed his bicycle to coast backwards downhill. Thereafter, control passes back to step 803 and the process continues as described above.
FIG. 9 shows an additional details for performing the functionality of step 807 of FIG. 8 . The process is entered in step 901 upon completion of performance of step 805 (FIG. 8 ). Thereafter, in step 903 (FIG. 9 ), the first object of the set of objects determined in step 805 (FIG. 8) is obtained. Next, in step 905 (FIG. 9 ), the size and location for the appendage screen is calculated. This calculation is performed taking into account, as will be appreciated by those of ordinary skill in the art, a) the location where the object to be displayed should be at in the frame of video to be displayed and b) the information available about the size of the object
Conditional branch point 905 then tests to determine if the just determined appendage screen can be merged with another appendage screen or the “main” video screen. If the test result in step 907 is YES, control passes to step 909 , and the just calculated appendage screen is merged with either another appendage screen which is substantially adjacent to it or the main video screen. Also, the section of the video information which is to be displayed on the merged appendage screens, or merged appendage screen and main screen, is prepared. Alternatively, if the test result in step 907 is NO, control passes to step 911 , which prepares the section of the video information which is to be displayed on the separate appendage screen. Note that such preparation may include any scaling or other processing of the video necessary to enhance the appearance of the object so that the viewer perceives the object to continue to exist as would naturally be expected.
Upon completion of steps 909 or 911 control passes to conditional branch point 913 , which tests to determine if the object for which an appendage screen was prepared is the last object for which an appendage screen needs to be prepared for this frame. If the test result in step 913 is NO, control passes to step 915 , to get the next object for which an appendage screen needs to be prepared. Control then passes back to step 905 and the process continues as described above. If the test result in step 913 is YES control passes to step 917 and the process is exited, so that control is passed to step 809 (FIG. 8 ).
Table 1 shows pseudocode for performing the process of FIG. 9 . To execute this pseudocode, prior to performing step 801 , it is necessary that there be supplied certain control parameters. These parameters include the following control variables:
expansion_bounds which controls how far appendage screens expand
consolidate_regions which controls appendage screen consolidations
consolidation_range which controls how close appendage screens must be to be eligible for consolidation
tear_off_regions which controls appendage screen break-aways
render_bounds which controls how far break-away appendage screens will move from their original screens
TABLE 1
Enter
FOR EACH object designated in step 805
calculate size and placement of an expansion region of
original video screen which would encompass object's new
location when rendered
IF new region is within expansion_bounds THEN
IF consolidate_regions is TRUE
AND the new region is within consolidation_range of
another expansion region THEN
consolidate new region with the
other expansion regions;
render new or consolidated region;
ELSE IF object location is NOT within expansion_bounds
AND tear_off_regions is TRUE THEN
IF new region is within render_bounds THEN
render new expansion region as separate video screen
end the “FOR EACH” loop
Exit | A limitation of a three dimensional world in which objects in the distance may be represented in only two dimensions as a video on a screen is that when an object within the field represented by the video undergoes a trajectory that takes it to a location in the world that is not represented by the video but instead is a location which is represented by computer graphics, namely, any portion of the object that is no longer on the video screen disappears. To overcome this limitation, when an object within the field represented by the video undergoes a trajectory that takes it to a location in the world that is not represented by the video on the video screen as currently configured, i.e., shaped and sized, the configuration of the screen is changed so that the object can continue to be displayed as video. The size and/or shape of the video screen is changed. For example, the video screen may be increased in overall size, or it may "grow" a specific appendage screen on which the object is displayed as video. If an additional appendage screen is "grown", it need not be contiguous with the screen as previously configured. Such appendage screens may sized, shaped, and located so that, the video object continues to be visible rather than becoming invisible because it is no longer displayable within the video screen. |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an RFID tag assembly and method for producing the tag assembly. The tag assembly includes an associated antenna and an attachment means for attaching the assembly to a material. The material may be flexible such as fabric or it may relatively rigid such as cardboard. In a preferred embodiment the invention may include a rivet containing a radio frequency identification (RFID) tag. In some embodiments the tag may be applied to the material in the vicinity of a structure present on the material which structure may function as a secondary antenna.
THE PRIOR ART
[0002] Use of a generic RFID tag on material such as fabric typically involves stitching the tag directly to the fabric or enclosing it within a patch to provide an enclosure for the tag. However this often leads to a bulky and inflexible solution particularly with a clothing garment that may be uncomfortable to wear.
[0003] In one prior art solution, a conductive thread is used to provide a secondary antenna and a plastic encapsulated RFID tag in the form of a traditional clothing button is stitched to the fabric in order to couple to the secondary antenna to form a larger overall tag system. While this solution is flexible and comfortable the thread link holding the button to the fabric loosens over time with repeated washing cycles and the button can rock about or tilt, deteriorating electromagnetic coupling between a primary antenna on the RFID tag and the secondary antenna associated the fabric.
[0004] An object of the present invention is to at least alleviate the disadvantages of the prior art.
SUMMARY OF THE INVENTION
[0005] The present invention may provide a two part tag solution, namely an RFID tag assembly including an associated or primary antenna formed with means for attaching the assembly to a material such as fabric or cardboard. In some embodiments the primary antenna may couple to a secondary antenna provided on or with the material. This solution may be particularly useful since use of ultra high frequency (UHF) as a carrier frequency for RFID tags has become more widespread following introduction of international UHF RFID standards. Although RFID protocols have converged, allowed regional UHF carrier frequencies have not. A separate secondary antenna may be useful for longer range operation because it may allow itself and thus the overall tag be optimised for an operating region, using a common and economically manufacturable generic tag which may account for most of the total cost.
[0006] The present invention may address the problems of the prior art by providing an RFID assembly such as a rivet to replace the unstable button. The rivet may be held firmly in place to maintain a relatively consistent electromagnetic coupling between the primary antenna associated with RFID tag and a secondary antenna associated with a flexible material such as a fabric item. The coupling may be substantially maintained throughout many washing cycles of the service life of the fabric item.
[0007] The body of the rivet may be constructed from plastics such as polyamide (e.g. Nylon), a fluoropolymer (e.g. polytetrafluoroethylene (PTFE) or Teflon), a urethane, or acrylonitrile butadiene styrene (ABS), all which may exhibit desirable working properties such as molding or machining and may be relatively soft for comfortable wearing on a clothing garment.
[0008] The RFID assembly may include a rivet and an RFID tag including a primary antenna. The RFID tag may include a substrate and an integrated circuit chip. The substrate may include a flexible film such as a polyester (e.g. polyethyleneterephthalate (PET)) for its ball bonding suitability for flip chip attachment of the RFID chip. Other substrates such as a polyamide or epoxy glass (e.g. FR4) are stiffer and thus less suited for reliable ball bonding assembly but are easier to die cut for small tag sizes and may make assembly easier to a plug part associated with the rivet.
[0009] The conductor of the primary antenna associated with the RFID tag is preferably aluminium for its low cost and resistance to corrosion, not only in end use but also in a manufacturing process. Other embodiments may include direct application of conductor to the rivet plug part, e.g. via sputtering, vapour deposition or printing, and subsequent bonding of the RFID chip to the conductor.
[0010] The RFID tag may be held in place on apart of a rivet such as a plug part with a potting material such as a urethane or epoxy resin which may fully surround the RFID tag for good seal against liquids and steam, and may remain relatively flexible for durable use on the fabric item.
[0011] The fabric item to which the rivet is applied may or may not include a hole. In a case where the fabric item includes a hole an assembled rivet may be relatively flat on the surface of the fabric as is preferable for a worn garment. During application of the rivet, the hole may facilitate easy alignment of the primary antenna associated with the RFID tag to the secondary antenna associated with the fabric. The secondary antenna may be formed by stitching a suitable antenna pattern using conductive thread around the hole such that the secondary antenna is flexible and relatively comfortable for a garment wearer.
[0012] In a case wherein the fabric item does not include a hole, a version of the rivet may be provided with larger tolerance on the rivet plug part such that an associated snap locking mechanism may accommodate the fabric in the locking mechanism. Although more bulky, this may be more suitable for fabrics such as linen (e.g. in a hotel, hospital, or restaurant), wherein no secondary antenna may be required or a larger secondary antenna (or the region close by the rivet) may be used to compensate for more tolerance on positioning of the RFID tag in the rivet relative to the secondary antenna on the fabric.
[0013] According to one aspect of the present invention there is provided an RFID tag assembly including as associated antenna and attachment means suitable for attaching the tag assembly to a material wherein said antenna and said attachment means comprise a unitary conductive frame. The material may be flexible such as fabric or it may be relatively rigid such as cardboard. The associated antenna may include a loop antenna.
[0014] The frame may be formed with a plurality of like frames by die stamping from a continuous roll of conductive material. The conductive material may include stainless steel or aluminium.
[0015] The attachment means may include a plurality of legs connected to the associated antenna. The free end of each leg may include a sharpened lead to penetrate the material. The tag assembly may include a backing plate for receiving the plurality of legs. The backing plate may include apertures on plural pitch circles to accommodate various thicknesses of material. The tag assembly may include means for short circuiting the associated antenna during assembly at least temporarily.
[0016] The material may be flexible and may include a secondary antenna. The tag assembly may be adapted to be attached to the flexible material such that the associated or primary antenna substantially maintains electromagnetic coupling with the secondary antenna when the flexible material flexes in use or is subject to repeated physical manipulation such as may take place during washing cycles.
[0017] The present invention may be embodied as a rivet including a tag assembly as described above. The rivet may include an RFID tag. The attachment means may be adapted to attach the rivet to a flexible material such that it may withstand repeated physical manipulation without detaching of the rivet. The flexible material may include fabric or an item of clothing. In some embodiments the secondary antenna may include a conductive thread stitched into the flexible material in the vicinity of the primary antenna.
[0018] According to a further aspect of the present invention there is provided a method of producing an RFID tag assembly including an associated antenna and attachment means suitable for attaching the tag assembly to a material including forming the antenna and the attachment means as a unitary conductive frame. The material may be flexible or relatively rigid.
[0019] The method may include forming the frame with a plurality of like frames by die stamping from a continuous roll of conductive material. The conductive material may include stainless steel or aluminium. The attachment means may include a plurality of legs connected to the antenna. The method may further include attaching an RFID chip to the antenna on the conductive frame. The method may further include encapsulating the RFID chip and the antenna on the conductive frame.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 shows a rivet plug and rivet ring;
[0021] FIG. 2 shows an RFID tag including an RFID chip bonded to a conductive track on an insulating substrate;
[0022] FIG. 3 shows the RFID tag placed onto the rivet plug;
[0023] FIG. 4 shows potting material added to hold and seal the RFID tag in place on the rivet plug to form an RFID rivet plug;
[0024] FIG. 5 shows a fabric with a hole around which a secondary antenna is stitched with conductive thread;
[0025] FIG. 6 shows the rivet ring placed into the hole in the fabric which facilitates alignment of the rivet to a secondary antenna;
[0026] FIG. 7 shows placement of a rivet plug and RFID tag which snap locks to the rivet ring to complete the RFID rivet;
[0027] FIGS. 8 to 10 show an alternative embodiment with a one piece rivet plug;
[0028] FIGS. 11 to 15 show a further embodiment of an RFID tag assembly with an extended tube section;
[0029] FIG. 16 shows a sew-on tag, wherein a primary antenna is held by conductive thread in proximity to a secondary antenna also constructed from conductive thread;
[0030] FIG. 17 shows a tag wherein a primary tag package is formed from two halves, one half having a relief slot such that an assembled primary tag package forms a tube through which part of the secondary antenna conductor passes;
[0031] FIG. 18 shows a rivet tag wherein a major part containing a primary antenna and an RFID chip is attached to the fabric by pushing metal legs through the fabric and folding the legs over against a minor retaining part;
[0032] FIGS. 19A to 19D show a conductive frame of the major part of FIG. 18 ;
[0033] FIG. 20 shows a circular variation of the rivet tag of FIG. 18 . which may be further used as an RFID press-stud;
[0034] FIG. 21 shows an inline process for producing a conductive frame and associated attachment parts;
[0035] FIGS. 22 to 27 show production steps 212 to 217 respectively of the inline process;
[0036] FIG. 28 shows an alternative form of loop antenna;
[0037] FIG. 29 shows a further form of loop antenna;
[0038] FIG. 30 shows an RFID press stud button and a backing plate;
[0039] FIGS. 31 to 34 show an RFID press stud button and backing plate being attached to fabric; and
[0040] FIG. 35 shows a modified version of the backing plate.
DETAILED DESCRIPTION OF THE INVENTION
[0041] Referring to FIG. 1 an RFID rivet is formed in two parts, a disc part or rivet plug 10 which snap locks into a rectangular toroid part or rivet ring 11 . The rivet plug 10 includes a smaller diameter raised tubular part 12 with an external barb 13 which mates to an internal barb recess 14 of a larger diameter raised tubular section of rivet ring 11 to provide a snap locking mechanism.
[0042] Referring to FIG. 2 , RFID tag 20 includes a primary antenna and RFID chip 21 bonded to a conductive track 22 formed on an insulating substrate 23 . Insulating substrate 23 comprises a rectangular toroid shape and may be die cut from a continuous web of complete RFID tags.
[0043] Referring to FIG. 3 , RFID tag 20 is placed over the raised tubular part 12 of rivet plug 10 and into an annular recess 15 of rivet plug 10 which is on the same side as raised tubular part 12 , the recess 15 having larger outside and smaller inside diameters than the corresponding diameters of RFID tag 20 . RFID tag 20 has one flat side facing or contacting the base of recess 15 in rivet plug 10 and the other flat side is exposed. The side of the RFID tag 20 facing the base of recess 15 in rivet plug 10 may have adhesive between itself and the base of recess 15 in rivet plug 10 to hold it in position before a potting step.
[0044] Referring to FIG. 4 , potting material 40 is poured into recess 15 of rivet plug 10 and flows to surround RFID tag 20 to hold and seal the RFID tag 20 to rivet plug 10 . The potting material 40 at least contacts part of upper regions of outer and inner diameter walls of recess 15 in rivet plug 10 and the exposed flat side of the RFID tag 20 in order to cap recess 15 and seal the RFID tag 20 to form a complete RFID rivet plug 41 .
[0045] A preferable situation is when potting material 40 contacts all outer and inner diameter walls of recess 15 in rivet plug 10 , and hence inner and outer walls of insulating substrate 23 of RFID tag 20 , and the exposed flat side of RFID tag 20 . This may occur if adhesive is used between RFID tag 20 and rivet plug 10 .
[0046] A more preferable situation is when potting material 40 contacts all outer and inner diameter walls of recess 15 in rivet pug 10 , and hence inner and outer walls of insulating substrate 23 of RFID tag 20 , and both the exposed flat side and side facing the base of recess 15 in rivet plug 10 of RFID tag 20 . In this situation RFID tag 20 may be totally sealed within potting material 40 and there may be no reliance on a seal created between potting material 40 and walls of recess 15 in rivet plug 10 permitting the rivet to flex more in use, or permitting use of difficult-to-bond materials for the rivet.
[0047] Referring to FIGS. 5 to 7 , fabric 50 is prepared with hole 51 around which a secondary antenna 52 is stitched with conductive thread. Hole 51 is preferably not button-holed or over-lock stitched to maintain an associated rivet flat or firm against fabric 50 . In severe duty use, such as industrial garments, an adhesive may be used between the two halves of a rivet in the region of hole 51 to prevent fraying of fabric 50 when stretched in use.
[0048] Embodiments without hole 51 are possible if the diameter of raised tubular section 15 which provides the snap locking mechanism between rivet plug 10 and rivet ring 11 is increased to accommodate fabric 50 . Various rivets or at least one of the rivet halves can be made with locking mechanisms adapted or sized to cater for varying fabric thickness. It may be preferable to provide a common complete RFID rivet plug 41 and varying rivet rings 11 . In such an arrangement rivet ring 11 may be sized to suit hole 51 to fit common complete RFID rivet plug 41 .
[0049] Versions of a rivet to be used with a hole may be used on smaller patches of fabric which may be subsequently stitched onto a main fabric item such that the main fabric item is without a hole. The advantages of good RFID tag to secondary antenna alignment and a simple RFID tag assembly may thereby be maintained.
[0050] Referring to FIG. 6 , raised tubular section 12 of rivet ring 11 fits into hole 51 in fabric 50 which facilitates easily achievable and good alignment of the rivet to secondary antenna 52 .
[0051] Referring to FIG. 7 , a complete RFID rivet plug 41 is pushed into rivet ring 11 such that the respective barbs 13 , 14 of the snap locking mechanism hold the complete rivet together. The arrangement may allow relatively good coupling between the primary antenna associated with the RFID tag and the secondary antenna to be maintained when the rivet is knocked about such as in a laundry process.
[0052] An alternative embodiment is shown in FIG. 8 wherein a rivet plug 80 is in one piece, which may be simpler to manufacture, and RFID tag assembly 82 is retained in a groove of rivet ring 81 by epoxy 83 .
[0053] FIG. 9 shows an addition to the alternative embodiment of FIG. 8 wherein a retaining boss 90 is pressed from the outer side of the rivet ring 81 to lock the assembly. FIG. 10 shows the RFID rivet of the alternative embodiment fully locked by retaining boss 90 .
[0054] A further embodiment is shown in FIG. 11 wherein a rivet plug 110 contains a RFID tag assembly 112 , retained by epoxy 113 in a groove of rivet plug 110 . The rivet plug 110 includes an extended tube section 115 which after assembly on fabric 114 is flared into and against a recess 116 on the outer face of rivet ring 111 . FIG. 12 shows initial assembly of parts of the embodiment shown in FIG. 11 . FIG. 13 shows an early stage of locking the RFID rivet of the embodiment with addition of a heated die 130 which flares the tube section of the rivet plug. The heated die 130 is pressed down against the extended tube section of the rivet plug which flares the extended tube outwards, and the heated die is pressed down until the extended tube section of the rivet plug is fully flared into the recess of the rivet ring.
[0055] FIG. 14 shows a last stage of locking the RFID rivet of the further embodiment wherein the heated die 130 has fully flared the tube section 115 of the rivet plug 110 into and against recess 116 in rivet ring 111 . FIG. 15 shows the RFID rivet of the further embodiment fully seated.
[0056] A sew-on embodiment is shown in FIG. 16 wherein RFID tag 160 includes a primary antenna 161 formed by conductor on substrate 162 and RFID chip 163 . Tag 160 is held by conductive thread 167 which is sewn through holes 166 in the tag 160 such that tag 160 is held in proximity to secondary antenna 164 also constructed from conductive thread sewn to fabric 165 . Alternate embodiments may use a semi-flexible substrate such as polyvinyl chloride (PVC) which may be directly sewn to the fabric without a need for pre-existing holes in the substrate.
[0057] A further sew-on embodiment is shown in FIG. 17 wherein a primary tag package is formed from two halves. A major substrate half 170 with primary antenna conductor 171 and RFID chip 172 , may have a relief slot 173 such that when a second minor substrate half 174 is bonded to the major substrate half 170 , the assembled primary tag package forms a tube through which part of the secondary antenna conductor 175 passes. The relief slot 173 may alternatively be made on the minor substrate half 170 . The secondary antenna conductor 175 is sewn using conductive thread to the base fabric and has a loop section formed by lifting the needle after some stitching and shifting the fabric before resuming stitching to form a loop section of the secondary around which the two primary tag package halves 170 , 174 may be assembled. The looping step may be repeated to increase thickness of the secondary antenna conductor in the coupling region, for reasons such as strength or conductivity. The loop may also be in the form of a wick which is sewn across a break in the secondary antenna conductor, or this wick may be already inserted into the tube formed by the two halves of the primary tag package and the assembly stitched across a break in the secondary. The assembled primary tag package may pivot on the secondary antenna which allows fabric surrounding the coupling vicinity to move relative to the primary tag package hence preventing fabric tearing or strain on the thread used to attach the primary tag. This may be the case when the fabric is subjected to bending wherein the fabric surface away from the primary tag has a larger bending radius than the primary tag, and the primary tag being rigid and held only at one edge slips relative to the fabric. Variations in construction may include a paper minor half such as a retail product label with a semi-circular cross sectioned crease as the slot, and a flexible major substrate half which includes an adhesive on one side such that when stuck onto the paper forms a tube wherein a product label may be attached to the product via a tie with a barbed push-together-clasp, wherein at least part of the tie is conductive to form the secondary antenna.
[0058] An embodiment of a rivet shown in FIG. 18 is based on dual in-line packaging (DIL packaging or DIP) wherein encapsulating material may be plastics or ceramic for extreme use such as in high temperature and pressure laundry applications. A major part 180 containing a primary antenna which is part of a conductive frame 181 and an RFID chip is sandwiched between a package top half 183 and package bottom half 184 . The major part 180 may be attached to the fabric by pushing the part 180 with a top die so that metal legs 182 push through the fabric and through holes 187 in a minor retaining part 186 , and folding the legs 182 over against a bottom die with curved slots which positions the minor retaining part 186 against the fabric and directs the ends of the legs 182 into recesses 188 of the minor retaining part 186 . Package bottom half 184 may include a recess 185 to provide clearance for the conductive thread. The minor retaining part 186 may be supplied on a reel to match the major part 180 on a separate reel for automated attachment.
[0059] FIGS. 19A and 19B shows a conductive frame 190 which is constructed from metal such as stainless steel, typically by die stamping, in a roll with legs 191 attached to a rectangular loop antenna 192 and to adjacent feeding frames (not shown). A small loop 193 , short circuits terminals 194 , 195 which are nickel-gold flashed to prepare a surface wherein RFID chip 196 is connected by bond wires 197 , 198 or is otherwise connected. Once RFID chip 196 is attached to conductive frame 190 , the two halves of the major part packaging may be bonded together sandwiching the conductive frame 190 therebetween with the short circuit loop 193 extending out beyond the packaging of the major part. Alternatively conductive frame 190 and RFID chip 196 may be encapsulated using an injection molding process known as overmolding. The packaged assembly may be left on the roll for automated assembly wherein it may later be die stamped out from the roll. The stamping process may form each leg 191 with a sharp lead in the form of tapered edge 199 and may also remove the short circuit loop 193 leaving small ends 200 , 201 as shown in FIG. 19B . The short circuit 193 is desirable during assembly to eliminate static electricity which could otherwise destroy the RFID chip during assembly.
[0060] FIG. 19C show an alternative example of a conductive frame 190 including sharpened leads in the form of barbs 202 . FIG. 19D shows a further example of a conductive frame 190 including sharpened leads in the form of tapered edges 203 . Tapered edges 203 may be similar to the edges formed on the legs of a staple.
[0061] Variations of the design may include a circular loop and associated parts for the major part 204 of an RFID tag assembly as shown in FIG. 20 . An RFID press-stud button, as shown may be formed using a circular variation of the major part 204 and insulating materials for the minor part 205 of the RFID tag assembly which forms the stud part of the press-stud on the opposite side of material 206 .
[0062] FIG. 21 shows inline steps for producing a conductive frame 210 including associated parts for the major part 211 of the RFID tag assembly as shown in FIG. 21 . The production steps include steps 212 to 217 which may be carried out at respective production stations as described below. Conductive frame 210 is constructed from metal such as stainless steel strip, typically by die stamping in a roll with legs 218 attached to circular loop antenna 219 and to peripheral border 220 of conductive frame 210 . Loop antenna 219 is short circuited via tracks 221 , 222 as described below. In one form conductive frame 210 may be formed from strip material approximately 35 mm wide.
[0063] FIG. 22 shows step 212 being carried out at a production station. Step 212 includes terminals 223 , 224 being spot nickel gold flash metallized to prepare surfaces wherein an RFID chip is attached at a subsequent station. Terminals 223 , 224 are short circuited via tracks 221 , 222 which are severed in a subsequent step. The short circuit serves to eliminate static electricity during assembly as described above.
[0064] FIG. 23 shows step 213 being carried out at a production station. Step 213 includes depositing a spot of conductive adhesive 230 to terminal 223 for attaching an RFID chip 240 as described below.
[0065] FIG. 24 shows step 214 being carried out at a production station. Step 214 includes attaching RFID chip 240 to terminal 223 of frame 210 via adhesive 230 .
[0066] FIG. 25 shows step 215 being carried out at a production station. Step 215 includes bonding wires 250 , 251 between terminals associated with chip 240 and terminals 223 , 224 of conductive frame 210 known as wedge bonding. Alternatively chip 240 may be surface mounted to terminals 223 , 224 known as ball bonding (not shown).
[0067] FIG. 26 shows step 216 being carried out at a production station. Step 216 includes encapsulation of antenna loop 219 on frame 210 via plastics packaging 260 using an injection molding process known as overmolding. The complete plastics package may be formed in one piece and in one molding step.
[0068] FIG. 27 shows step 217 being carried out at a production station. Step 217 includes severing of encapsulated antenna loop 219 and legs 218 from peripheral border 220 . Step 217 also includes severing of tracks 223 , 224 to open circuit antenna loop 219 and testing of the assembly. Step 217 may also include turning of legs 218 to form the major part 211 .
[0069] FIG. 28 shows an alternative form of primary loop antenna 280 that may be formed with conductive frame 210 in place of loop antenna 219 shown in FIGS. 21 to 27 . Loop antenna 280 is formed with spiral or arc extensions 281 and legs 282 which correspond to legs 191 in the previously described embodiment. However, unlike loop antenna 219 which is open circuit, loop antenna 280 is closed circuit and includes cruciform conductors 283 that are adapted to interface with two ports (two RF inputs) of a modified version of chip 240 .
[0070] FIG. 29 shows a further form of primary loop antenna 290 that may be formed with conductive frame 210 in place of loop antenna 219 shown in FIGS. 21 to 27 . Loop antenna 290 is formed with serpentine extensions 291 and legs 292 which correspond to legs 191 in the previously described embodiment. Loop antenna 291 includes cruciform conductors 293 which perform a similar function to conductors 283 described above.
[0071] FIG. 30 shows the major part 211 of the RFID tag assembly comprising an RFID press stud button and a minor part 284 comprising a backing plate formed from an insulating material such as plastics. Minor part 284 includes recesses 285 for receiving respective legs 218 and a through aperture 286 located on a circle associated with each recess 285 .
[0072] FIG. 31 shows the major part 211 positioned above a secondary antenna 294 stitched into fabric 295 with conductive thread. Minor part 284 is positioned under the fabric 295 for mating with major part 211 as described below.
[0073] FIG. 32 shows the underside of the fabric 295 after legs 218 of major part 211 have penetrated fabric 295 . Minor part 284 is positioned so that each leg 218 is adjacent a respective recess 285 which extends to the underside of minor part 284 .
[0074] FIG. 33 shows the underside of the fabric 295 after legs 218 are bent towards the centre of minor part 284 so that each leg 218 lies in a respective recess 285 and the tip 310 of each leg 218 over lies a respective aperture 286 in minor part 284 .
[0075] FIG. 34 shows the underside of the fabric 295 after the tip 310 of each leg 218 is bent into a respective aperture 286 to provide for parts 211 and 284 to be securely held together after repeated washing cycles.
[0076] FIG. 35 shows a modified version of minor part 284 including a further set of through apertures 330 . The further set of apertures 330 are located on a pitch circle that is larger in diameter relative to the circle on which apertures 286 are located. This is, apertures 330 are spaced further out from the centre of minor part 284 and are adapted to accommodate attachment of parts 211 and 284 to fabric 295 that is proportionately thicker.
[0077] Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention. | A method is disclosed of producing an RFID tag assembly including an associated antenna and attachment means suitable for attaching the tag assembly to a material. The material may be flexible such as fabric or relatively rigid such as cardboard. The method includes forming the associated antenna and the attachment means as a unitary conductive frame. An RFID tag assembly produced by the method is also disclosed. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of surfactants and more particularly to a surfactant which enables the manufacture of emulsion polymers at high solids levels.
2. Description of the Prior Art
Vinyl acetate copolymer emulsions having a solids content of 65% by weight are known and some are articles of commerce. Such emulsions, however, often require high levels of surfactant or protective colloid to achieve the required stability to shearing forces and to freezing. In addition, such techniques as delayed surfactant addition or the use of monomer pre-emulsions are often required in order to achieve manageable viscosities. These departures from conventional practice, while successfully producing 65% solids latexes, can lead to undesirable properties such as reduced resistance to moisture and unsatisfactory rheological properties. The variations from conventional procedures may also require equipment changes and result in a more expensive process.
High solids vinyl acetate emulsion polymers are prepared by various methods. Such polymers may be prepared using pre-emulsified monomers or using a higher than normal surfactant level. Still another method uses delayed surfactant addition. U.S. Pat. No. 4,409,355 uses a multistage monomer addition to prepare latexes with 60% or more solids. In U.S. Pat. No. 3,423,353, large increments of initiator are added after the reaction is completed to achieve the desired viscosity.
Accordingly, it is an object of the present invention to provide a surfactant which eliminates the need for such complex methods for preparing high solids emulsion polymers. It is a related object of the present invention to provide a surfactant which may be used to prepare stable, high solids emulsion polymers simply and economically.
SUMMARY OF THE INVENTION
The invention comprises a surfactant which enables emulsion polymers to be prepared at high solids levels via simple processes, at reasonable surfactant levels, and in readily available equipment. The surfactant comprises a blend of a nonyl phenol tetra ethoxylate, the salt of a sulfated nonyl phenol tetra ethoxylate and a sulfate salt. The concentration of each of these materials may vary. Preferably the nonyl phenol tetra ethoxylate and the sulfated derivative thereof comprise the major proportion, by weight, of the surfactant. Most preferbly, the surfactant comprises about 37 wt.% nonyl phenol tetra ethoxylate, about 53 wt.% nonyl phenol tetra ethoxylate sulfate, and 10 wt.% sodium sulfate.
In the preparation of an emulsion polymer the surfactant components may be charged in their entirety to the reactor prior to reaction, thereby allowing the monomers to be added as a simple blend. The process for preparation of high solids emulsion polymers is therefore simplified and the chance for error is greatly reduced. The reaction requires less operator attention and thus is less costly. The process yields a low viscosity product with good stability.
The surfactant may be made by partially reacting the nonyl phenol tetra ethoxylate with a sulfating agent to form the appropriate sulfated ethoxylate/ethoxylate mixture, or by simply mixing the three ingredients.
DETAILED DESCRIPTION OF THE INVENTION
The surfactant of the present invention consists of a blend of three essential components. The first component is a nonionic surfactant made by reacting nonyl phenol with ethylene oxide to form a polyether containing, on the average, four moles of ethylene oxide. The average is determined from the hydroxyl value of the polyether surfactant. The reaction product is referred to as nonyl phenol tetra ethoxylate or as the tetra ethoxylate. The second component is formed by reacting the tetra ethoxylate with a suitable sulfating agent such as, for example, sulfur trioxide. The acid product from this reaction is neutralized with a base of choice, for example, an alkali metal hydroxide such as sodium hydroxide. Other examples of suitable bases would include ammonium hydroxide and amines. The third component is the sulfate of the neutralizing base. When sodium hydroxide is used as the neutralizing base, the third component is sodium sulfate.
The surfactant blend of the present invention can be prepared in several ways. Illustrative of the techniques which may be used are the following. The blend can be made by partial sulfation of the nonyl phenol tetra ethoxylate, i.e., by reacting nonyl phenol tetra ethoxylate with somewhat less than an equimolar quantity of sulfur trioxide such that the resulting product is approximately 60% by weight anionic ether sulfate and approximately 40% nonionic nonyl phenol tetra ethoxylate. An aqueous dispersion of the anionic and nonionic components is prepared to which is added sodium sulfate such that the final product contains 2.9% sodium sulfate by weight of the total dispersion. The sodium sulfate serves to stabilize the dispersion. The three components are effective over a range of concentrations. The non-volatile content of the final dispersion is determined by evaporation for two hours in a drying oven maintained at 105° C., and is about 29%.
The blend may also be prepared prior to charging the polymerization vessel by mixing about 37 parts of the nonionic nonyl phenol tetra ethoxylate with about 53 parts of the fully reacted nonyl phenol tetra ethoxysulfate and about 10 parts of sodium sulfate.
Alternatively, the unmixed surfactant components may simply be charged to the polymerization vessel. Any of these methods may be used without departing from the invention.
The surfactant of the present invention is useful in the emulsion polymerization of alpha, beta-ethylenically unsaturated monomers. Examples of such monomers are styrene, vinyl toluene, methacrylic acid and derivatives thereof, acrylic acid and derivatives thereof, halogenated monomers such as vinyl chloride and vinylidene chloride, and vinyl esters. The surfactant is especially useful with vinyl acetate copolymer emulsions wherein it is desired to prepare the emulsion at a solids level approximately 65% by weight. Emulsions made using the surfactant of the present invention are not only stable but also exhibit satisfactory viscosity for typical commercial application.
It is believed the surfactant of the present invention facilitates polymerization by forming micelles which solubilize the monomer starting materials. It is also believed that the presence of the sulfate of the neutralizing base causes the micelle to expand so that more polymer (i.e., higher solids) can be brought into the emulsion.
The surfactant of the present invention may be used to prepare high solids latexes as follows. First, water, a protective colloid, the surfactant, and a pH buffer such as NaHCO 3 are charged to a suitable reaction vessel. The mixture is then heated to reaction temperature under a blanket of inert gas and with stirring at which point is added a polymerization initiator such as, potassium persulfate, for example and from about 5% to 20% of the monomer or blend. An exothermic reaction occurs and is allowed to subside whereupon is begun the gradual addition of the remaining monomer and additional initiator. These additions take place over a specified time period which is dependent upon removal of the heat of reaction. Such time period may be anywhere from one to six hours, typically three to five hours. During that time, the product increases in viscosity to that of or slightly exceeding the viscosity of the final product. Significantly, at no time does the viscosity of the reaction mixture become so high as to be considered unmanageable. Departures from or modifications of the above procedure may be made and will be obvious to one skilled in the art. Such modifications are within the scope of the invention.
The protective colloid may be any water soluble polymeric material commonly used for this purpose. Examples are polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether/maleic anhydride, natural gums such as gum arabic or guar gum and various cellulose derivatives such as hydroxyethyl cellulose or sodium carboxymethyl cellulose. Hydroxyethyl cellulose is preferred. Materials such as glycols may be added as may additional surfactants without departing from the invention.
Example 1 illustrates the stability of the surfactant of the present invention.
EXAMPLE 1
A nonyl phenol tetra ethoxylate was reacted in a continuous falling film reactor with 64.7% of the stoichiometric quantity of sulfur trioxide. The resulting sulfuric acid was neutralized with aqueous NaOH. Sufficient nonyl phenol tetra ethoxylate was added to adjust the nonionic content to 40% of the active surfactant. An aqueous dispersion was prepared to which sodium sulfate was added to an arbitrarily determined level of 2.5-3.0% of the total dispersion. The dispersion was milky and did not separate upon ageing either at room temperature or at 50° C. or upon freezing. The dispersion is stable, however, only when the sodium sulfate is added. The final composition was as follows:
______________________________________Anionic Content 15.04%Nonionic Content 10.60%Na.sub.2 SO.sub.4 2.91%Solids, Content 29.25%______________________________________
A similar dispersion prepared without the sodium sulfate separated into distinct layers upon standing overnight.
Examples 2-9 illustrate the preparation of latexes using the surfactant of the present invention. Among the characterizing parameters presented are coagulum content and mechanical stability. Coagulum is the weight % of residue that results when the latex is poured through a double layer of cheesecloth, and the cloth washed with cold water. Mechanical stability is assessed after mixing the latex in a Hamilton Beach drink mixer for 15 minutes. All viscosities were measured with a Brookfield viscometer spun at 30 r.p.m using various spindles.
EXAMPLE 2
To a glass polymerization vessel was added 202.8 parts deionized water, 2.2 parts Cellosize WP-09 (hydroxethyl cellulose), 85.2 parts of the surfactant of Example 1, 24.0 parts of Polystep B-19 (a polyethoxysulfate of lauryl alcohol containing 30 moles of ethylene oxide), and 2.2 parts NaHCO 3 . This was heated with stirring to 65° C. while a flow of nitrogen was maintained across the mix. At this point, one part of K 2 S 2 O 8 and 62.4 parts of a monomer mix consisting of 498.9 parts vinyl acetate and 124.7 parts butyl acrylate were added and allowed to react until the resulting exotherm subsided. Addition of the remaining monomer mix was begun at this time and carried out a constant rate over a period of 4.5 hours. During this time a solution of 0.7 parts K 2 S 2 O 8 in 58.3 parts deionized water was added in five equal increments at equal intervals. The resulting latex displayed the following properties:
______________________________________Solids 63.9%pH 5.1Viscosity (#4 spindle) 2850 cpsCoagulum 0.06%Mechanical Stability good______________________________________
EXAMPLE 3
The procedure of Example 2 was repeated using 95.9 parts of the surfactant of Example 1 and 5.2 parts of Polystep B-23 (a polyethoxysulfate of lauryl alcohol containing 12 moles of ethylene oxide). The initial water charge was 210.9 parts. A satisfactory latex resulted having a lower viscosity than that of Example 2, but which contained a trace of grit.
______________________________________Solids 64.46%pH 5.17Viscosity (#4 spindle) 1850 cpsCoagulum 0.06%Mechanical Stability good______________________________________
EXAMPLE 4
The procedure of Example 3 was repeated using 11.1 parts of Polystep B-27 (a polyethoxysulfate of nonyl phenol containing 4 moles of ethylene oxide) instead of the Polystep B-23. The initial water charge was 205 parts. A satisfactory latex resulted which contained a trace of grit.
______________________________________Solids 64.39%pH 5.2Viscosity (#4 spindle) 1980 cpsCoagulum 0.08%Mechanical Stability good______________________________________
EXAMPLE 5
The latex of Example 2 was repeated using Polystep F-95B (a nonyl phenol polyethoxylate containing 34 moles of ethylene oxide) as a nonionic cosurfactant. It was found that a substantial portion of the surfactant mix had to be nonionic in order to achieve results comparable to the earlier samples. Even then, the grit content was noticeably higher. Thus, 42.6 parts of the surfactant of Example 1 and 26.7 parts of Polystep F-95B were charged along with 242.7 parts of water. A satisfactory latex resulted.
______________________________________Solids 64.34%pH 5.2Viscosity (#3 spindle) 996 cpsCoagulum 0.68%Mechanical Stability good______________________________________
EXAMPLE 6
For comparative purposes the latex of Example 5 was repeated using a commercial octyl phenol based surfactant of similar composition to and in place of the surfactant of Example 1. A latex resulted which had an unsatisfactory high level of coagulum and inferior stability.
______________________________________Solids 64.76%pH 5.09Viscosity (#3 spindle) 1216 cpsCoagulum 1.11%Mechanical Stability poor______________________________________
EXAMPLE 7
The preparation of Example 6 was repeated with the exception that the surfactant components were charged directly to the reaction vessel. The anionic component was 56.9% of the total weight of the surfactant. The nonionic and sodium sulfate components were 35.5% and 7.6%, respectively, of the total surfactant. A satisfactory latex resulted.
______________________________________Solids 64.34%pH 5.1Viscosity (#4 spindle) 1320 cpsCoagulum 0.11%Mechanical Stability excellent______________________________________
EXAMPLE 8
An acrylic latex was prepared in a manner similar to Example 2 by charging 448.1 parts deionized water, 45.0 parts of the surfactant in Example 1, and 15.7 parts Polystep B-27 to a polymerization vessel and heating under nitrogen to 70° C. At this point 0.5 parts K 2 S 2 O 8 and 20% of a monomer mix consisting of 215 parts each of butyl acrylate and methyl methacrylate and 8.8 parts methacrylic acid are added and the mix allowed to react until the exotherm subsides. The addition of the remaining monomer is then begun at a rate such that the addition is completed in one hour. Concommitantly, but separately, is added a solution consisting of 36.6 parts deionized water and 1.5 parts K 2 S 2 O 8 . After the additions have been completed, the temperature is maintained at 70°-75° C. for an additional hour, whereupon the latex is cooled to ambient temperature. A mixture consisting of 5.1 parts deionized water and 5.1 parts 28% ammonia is added to adjust the pH. A satisfactory latex is obtained.
______________________________________Solids 45.23%pH 8.93Viscosity (#1 spindle) 64 cpsCoagulum 0.08%______________________________________
EXAMPLE 9
A styrene acrylic latex was prepared in the manner of Example 9 by replacing the methyl methacrylate with styrene and using 30 parts of the surfactant of Example 1 and 22 parts of Polystep A-18-S (alpha olefin sulfonate). A satisfactory latex resulted.
______________________________________Solids 44.62%pH 9.07Viscosity (#3 spindle) 2504 cpsCoagulum 0.32%______________________________________ | A surfactant for use in the preparation of high solids emulsion polymers comprises nonyl phenol tetra ethoxylate, the sulfate salt of the tetra ethoxylate and a sulfate salt. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to hose reels and, more specifically, to a storage device for a hose having a system whereby a user can selectively pull a hose out to a desired length and selectively withdrawn back into the storage device by means of utilizing potential energy stored within a block and tackle mechanism that is charged by the pulling of the hose out of the device. In the fully retracted position the hose is wound around a plurality of upper and lower hose guides having a plurality of rollers set apart at a gapping where said hose is held in an oval like configuration so that when the hose is withdrawn potential energy is stored in a block and tackle device until selective release whereupon the block and tackle mechanism exerts the stored potential energy into retracting the hose back to its original oval like winding.
2. Description of the Prior Art
There are other winding devices designed for spooled material. Typical of these is U.S. Pat. No. 4,023,387 issued to Gould on May 17, 1977.
Another patent was issued to Johnston, et al. on May 6, 1986 as U.S. Pat. No. 4,586,676. Yet another U.S. Pat. No. 4,723,568 was issued to Adams on Feb. 9, 1988 and still yet another was issued on Jun. 2, 1992 to Carlson as U.S. Pat. No. 5,117,859.
Another patent was issued to Pillin on Jul. 28, 1947 as U.K. Patent No. GB590,766. Yet another U.K. Patent No. GB796,205 was issued to ARO Equipment Corporation on Jun. 4, 1958. Another was issued to UK Atomic Energy Authority on Nov. 28, 1962 as U.K. Patent No. GB911,635 and still yet another was issued on Oct. 8, 1969 to Dean Manufacturing Engineers as U.K. Patent No. GB1,166,842. Another patent was issued to Hosoyama on Aug. 17, 1984 as Japanese Patent No. JP59143878. Yet another German Patent No. DE3309319 was issued to Kuestermeyer on Sep. 20, 1984. Another was issued to Richiyaado on Oct. 27, 1995 as Japanese Patent No. JP7284215. Another was issued to Bertagna on Oct. 22, 1997 as U.K. Patent No. GB2,312,198.
U.S. Pat. No. 4,023,387
Inventor: Ronald Jay Gould
Issued: May 17, 1977
A cable employing device for securing frames to poles and posts; a cable dispensing and recovering casing secureable to a frame which includes releaseable engaging means for one cable end; an improved tensioning system for a cable dispensing casing which ordinarily retains the cable in the casing and returns the cable to the casing after use; a cable retention and return device for use in a cable dispensing container which employs a length of surgical tubing to power the cable retention and return; hinged enclosures for simultaneous enclosure of a cable dispensing system and engagement of a frame support.
U.S. Pat. No. 4,586,676
Inventor: Damon A. Johnston, et al.
Issued: May 6, 1986
A garden hose storage apparatus having a base and a storage reel rotatably mounted on the base for windably receiving a garden hose. A shelf is secured to the base. The shelf contains an aperture for movably receiving a garden hose. A plurality of rollers is rotatably mounted in the aperture. Said rollers are engageable with the hose to facilitate movement of the garden hose through the aperture for guiding the garden hose on and off the reel.
U.S. Pat. No. 4,723,568
Inventor: Truman W. Adams
Issued: Feb. 9, 1988
A hose reel mechanism designed for carrying two separate, yet interconnected, lengths of hose includes a tubular metal frame which is provided with support wheels, a supporting base portion and a handle portion. Carried by this frame are two substantially identical hose reels, each of which are supported by an axle, the ends of each axle being secured by the sides of the frame. Each reel is designed to receive a length of hose wherein the hose disposed on the lower reel connects to the faucet and the hose on the upper reel is used for watering at a remote-use location. As the frame is moved away from the faucet, the hose wound on the lower reel is able to unwind automatically and once the frame is positioned at the desired location, the length of hose on the upper reel may be pulled at its free end for unwinding that hose from the top reel. When the watering activity is finished, the length of hose on the upper reel may be rewound onto that reel manually or alternatively by a spring-loaded mechanism, and the length of hose on the lower reel rewinds automatically as the frame is pushed back toward the faucet due to the driving action of the wheels and a belt and pulley arrangement which connects the wheel axle to the axle of rotation of the lower reel.
U.S. Pat. No. 5,117,859
Inventor: James B. Carlson
Issued: Jun. 2, 1992
An above-ground gravity return hose retractor, which is particularly useful in service stations for supplying air and water, encloses the hoses and the retraction mechanism within a cabinet. A block and tackle pulley arrangement, including a vertically movable pulley sheave supported by the hose, is located within the cabinet. The movable pulley sheave has a non-linear, variable weight attached to it in the form of an elongated chain having a first segment of small, relatively lightweight links attached through a limit spring to the sheave. These lightweight links then are attached to an additional segment of chain having intermediate weight links, with the lowermost portion of the chain comprising larger, heavier links. The final link in the chain is attached to the bottom of the cabinet. The full length of the chain is reached just prior to the final extension of the hose. The limit spring then provides a significant increase in resistance to further withdrawal of the hose when the chain is fully extended. Upon release, the variable weight chain exerts the greatest pulling force upon initial retraction of the hose, and the retraction pulling force decreases non-linearly to its lowest value when the hose is nearly fully retracted.
U.K. Patent Number GB590,766
Inventor: John Burgoyne Pillin
Issued: Jul. 28, 1947
A self-coiling reel for a hose pipe, cable or the like has a pneumatically-operated rewinding mechanism which is conditioned for operation by withdrawing the hose from its reel. One embodiment of the invention, FIGS. 1 and 2, for a lubricant supply servicing device has a hose 11 wound on the reel 8, which is supported in the casing 1 on a spindle 6 rotatably mounted in the bearing 3 secured to standard; 2 by dowel pins 4 and retaining clips 5, to which is connected the small sprocket 26 engaging a common chain with the sprocket 28 formed integrally with a cable drum 37 mounted rotatably on the shaft 31. A cable 38 from the drum 37 is connected to a piston rod 39 and a piston 40 working in a cylinder 41 which is supplied at its upper end with compressed air through the gland 42, push button valve 44 and tubes 43 and 46. The inner end of the hose 11 is connected to the screwed socket 19 and receives lubricant through the bores 18 and 12 of the flanges 7 and the spindle 6 respectively from the screwed socket 17. The tube 11 is pulled through a fairlead 20 in the casing 1 thus rotating the drum 38 and hence pulling the piston 40 to the top of its stroke, the air in the cylinder being allowed to bleed away through passages 47. When required lubricant servicing is completed the button 45 is pressed to allow air to enter the cylinder 41 above the piston 40 and so force it downwards thus rotating the drums 38 and 8 hence winding the hose 11. In a modification, FIG. 3, the hose 11 is wound round a series of pulleys 48 and 51 supported by a bracket 50 and frame 53 respectively. The frame 53 is connected to a pulley 58 by a cable 59 and a further cable 38 connected to the piston rod 39 encircles a pulley 37 formed integral with the pulley 58. The hose 11, connected direct to a lubricant supply on the casing 1, has its upper end pulled through the fairlead 20 thus pulling the frame 53 upward and the piston downward. When the button 45 is pressed the piston ascends and pulls the frame 53 vertically downward thus drawing in the hose 11.
U.K. Patent Number GB796,205
Inventor: Aro Equipment Corporation
Issued: Jun. 4, 1958
The outlet end 14 of a hose 10 wound on a rotatable reel R is traversed horizontally by a cable 12 connected to the hose end 14 and extending over a pulley P back to the drum on which it is wound in the opposite direction to the hose 10. The reel R, FIG. 4, is rotatably mounted on an axle 32 serving as a supply conduit, e.g., for lubricating oil or compressed air, and fixed in a frame 24 adapted to be attached by brackets 30 to a ceiling 48. The hose 10 is wound on one section 20 of the reel and the cable 12 on a larger diameter section 60, the difference in diameters being the same as the difference between the diameters of the hose and cable or slightly greater to keep the hose taut. The inner end of the hose is connected to a fluid tight coupling 38 surrounding the axle 32 and the outer end is connected to a member 14, FIG. 1A, having an eye 68 for connection of the cable 12 and a flow port for connection of a pipe 16 leading e.g., to a lubricant gun or pneumatic tool. A second cable 62 may be provided in the hose 10 and anchored in the member 14 and coupling 38 to counteract stretching of the hose during unreeling. The hose is guided on to the reel by a grooved wheel 50, FIG. 6, journalled on a threaded rod 52 which causes the wheel 50 to travel across the drum during reeling and unreeling, a bar 54 holding the hose on the wheel 50. In a modification the wheel 50 is freely journalled on a smooth rod.
U.K. Patent Number GB911,635
Inventor: UK Atomic Energy Authority
Issued: Nov. 28, 1962
The outlet end 14 of a hose 10 wound on a rotatable reel R is traversed horizontally by a cable 12 connected to the hose end 14 and extending over a pulley P back to the drum on which it is wound in the opposite direction to the hose 10. The reel R, FIG. 4, is rotatably mounted on an axle 32 serving as a supply conduit, e.g., for lubricating oil or compressed air, and fixed in a frame 24 adapted to be attached by brackets 30 to a ceiling 48. The hose 10 is wound on one section 20 of the reel and the cable 12 on a larger diameter section 60, the difference in diameters being the same as the difference between the diameters of the hose and cable or slightly greater to keep the hose taut. The inner end of the hose is connected to a fluid tight coupling 38 surrounding the axle 32 and the outer end is connected to a member 14, FIG. 1A, having an eye 68 for connection of the cable 12 and a flow port for connection of a pipe 16 leading e.g., to a lubricant gun or pneumatic tool. A second cable 62 may be provided in the hose 10 and anchored in the member 14 and coupling 38 to counteract stretching of the hose during unreeling. The hose is guided on to the reel by a grooved wheel 50, FIG. 6, journalled on a threaded rod 52 which causes the wheel 50 to travel across the drum during reeling and unreeling, a bar 54 holding the hose on the wheel 50. In a modification the wheel 50 is freely journalled on a smooth rod.
U.K. Patent Number GB 1,166,842
Inventor: A.G. Dean Manufacturing
Issued: Oct. 8, 1969
A reel for hoses, cables and the like comprises a rotatable drum on which the material is wound, power-operated means connected to the drum to rewind any material dispensed from the drum, and means to disconnect the power operated means from the drum to enable, when required, material to be freely dispensed from the drum. The power-operated means includes a pulley mounted coaxially on the drum, and a further pulley 30 connected to a motor 25 via a reduction gearing 28, a belt 31 being provided and passing round both pulleys. The means to disconnect the power-operated means from the drum comprises means to release the tension in the belt 31; this is effected by means of an eccentrically mounted roller 32 which is movable away from the belt via a handle 36. An adjustable stop 37 enables a predetermined tension to be applied to the belt. A bevel gear 38 and pinion 39 are provided for manual operation of the drum in the event of an emergency. The drum is mounted on a hollow shaft rotatably mounted on a stationary hollow spindle. The hollow spindle communicates with a collecting housing from which a duct leads for connection to a hose for the supply of liquid; liquid-tight seals are provided between the spindle and the collecting housing.
Japanese Patent Number JP59143878
Inventor: Hosoyama Yoshitarou
Issued: Aug. 17, 1984
PURPOSE: To improve workability by placing a winding cock connected to a hose, near a spray nozzle mounted on the end of said hose and enabling said hose to be automatically wound around a winding drum by means of the closing action of said cock. CONSTITUTION: When a spray cock 64 is closed at the end of a sprinkling operation of a chemical liquid, etc., while a winding cock 62 is also closed, a liquid in a hose 8 and an introduction tube 19 is prevented from flowing outside through a delivery pipe 63, causing liquid pressure working on the right side of a piston 16 to be great and moving the piston 16 leftward. Then, a three-way valve 22 is shifted through a piston rod 15 and a shifter 20, allowing the liquid to flow through introduction tubes 24, 24′ into a winding cylinder 2. Accordingly, a piston rod 5 is raised, a pressing roller r1 is pressed against the pulley 2 side of a belt 3 through a tension lever 4, and a winding drum D is rotated through the pulley 2 driven by a prime mover E, the belt 3, and a pulley 1, winding the hose 8.
German Patent Number DE3309319
Inventor: Kuestermeyer Franz Josef
Issued: Sep. 20, 1984
This device is used to guide a power connecting cable, one end of which is always fitted in a plug socket, through an opening in a housing into the interior of the housing, which cable then emerges again via rollers in the housing which are arranged like pulley blocks and at a different point, which is capable of sliding for the cable, if necessary with the aid of a roller, and is equipped at the other end with a plug contact, or is connected permanently or by means of a plug contact to an electrical apparatus, and, if required, remains tensioned corresponding to the respectively selected number of rollers and the weight which is in each case located on the lower roller or rollers, and is available in the respectively required length.
Japanese Patent Number JP7284215
Inventor: Richiyaado EE Baataguna, et al.
Issued: Oct. 27, 1995
PURPOSE: To provide the highly reliable cord retractor device, whose structure is simple and life is long. CONSTITUTION: In this device, a first cord pulley 82 of the first end part of a frame, second cord pulleys 60 and 62 of the second end part and a cord 90, which is wound around these pulleys so that one end 92 is fixed to the first end part 92, and the other end extends from the other end of the frame, are provided. Furthermore, a sliding block, which slidably attaches the second cord pulleys 60 and 62, so that the pulleys are made to approach the first cord pulley 82 along the frame and separated, a spring, which pushes the second cord pulleys 60 and 62 to the second frame end part, and a latching means, which releasably fix the second cord pulleys 60 and 62 to the position approaching the first cord pulley 82, are provided. The second cord pulleys 60 and 62 are moved to the latching position by the pulling with the end of the cord 90, and the cord is extracted.
U.K. Patent Number GB2312198
Inventor: Richard A. Bertagna, et al.
Issued: Nov. 21, 1994
A cord retractor comprises an elongate frame having first and second frame ends to which laterally spaced tracks 18, 20, 22, 24 are fixed and extend therebetween, a first pulley means 82, 84 mounted to the frame at the first end, a pair of movable supports mounted respectively in the tracks for movement between the frame ends, a second pulley means 60, 62 journalled to and positioned between the movable supports, means for urging the movable supports and the second pulley means towards the second frame end, and an intermediate cord storage section 90 wound over each of the pulley means wherein one end 92 of the cord storage section is fixed to one of the frame ends and the other end 106 of the cord storage section is provided with a free end which extends from the frame. Preferably, a latch means 126 releasably secures the movable supports in a latched position adjacent the first frame end, each of the supports having a low friction slide block 50, 52 slidably mounted in the tracks. The means for urging the movable supports and the second pulley means may comprise first and second spring wheels 66, 68 mounted to the frame at the second frame end, wherein first and second tension springs 70, 72 may pass over the spring wheels such that one end thereof may be secured to one of the slide blocks whilst an opposite end may be secured to the first frame end.
While these reel devices may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described.
SUMMARY OF THE PRESENT INVENTION
A primary object of the present invention is to provide an apparatus for dispensing and retrieving a length of hose.
Another object of the present invention is to provide a storage device for a hose having a system whereby a user can selectively pull a hose out to a desired length and selectively rewind back into the storage device
Yet another object of the present invention is to provide an apparatus for a hose using a spring and block and tackle for storing potential energy.
Still yet another object of the present invention is to provide an apparatus for a hose wherein the block and tackle mechanism is charged by pulling the hose out of the storage device.
Another object of the present invention is to provide an apparatus for a hose whereby in the fully retracted position the hose is wound around a plurality of upper and lower hose guides having a plurality of rollers set apart at a gapping.
Yet another object of the present invention is to provide an apparatus for a hose wherein the hose is held in an oval like configuration so that when the hose is withdrawn potential energy is stored in a block and tackle device until selective release.
Still yet another object of the present invention is to provide an apparatus for a hose wherein the block and tackle mechanism exerts the stored potential energy into retracting the hose back to its original storage device.
Additional objects of the present invention will appear as the description proceeds.
The present invention overcomes the shortcomings of the prior art by providing a storage device for a hose having a system whereby a user can selectively pull a hose out to a desired length and selectively withdrawn back into the storage device by means of utilizing potential energy stored within a block and tackle mechanism that is charged by the pulling of the hose out of the device. In the fully retracted position the hose is wound around a plurality of upper and lower hose guides having a plurality of rollers set apart at a gapping where said hose is held in an oval like configuration so that when the hose is withdrawn potential energy is stored in a block and tackle device until selective release whereupon the block and tackle mechanism exerts the stored potential energy into retracting the hose back to its original oval like winding.
The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawings, which forms a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawings, like reference characters designate the same or similar parts throughout the several views.
The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
In order that the invention may be more fully understood, it will now be described, by way of example, with reference to the accompanying drawing in which:
FIG. 1 is an illustrative view of the present invention in use.
FIG. 2 is a perspective view of the present invention.
FIG. 3 is a perspective view of the internal components present invention.
FIG. 4 is a front view of the internal components present invention in the wound position.
FIG. 4A is a perspective view of an end cap on a guide track of the present invention.
FIG. 4B is a perspective view of a stop on a guide track of the present invention.
FIG. 5 is a front view of the internal components present invention in the unwound position.
FIG. 5A is a perspective view of the nipple of the present invention.
FIG. 6 is a top and side view of the bottom hose guide of the present invention.
FIG. 7 is a top and side view of the top hose guide of the present invention.
FIG. 8 is a perspective view of the bottom hose guide of the present invention.
FIG. 8A is a perspective view of a fixing plate of the present invention.
FIG. 8B is perspective view of a modified brace of the present invention.
FIG. 9 is a perspective view of the ratchet mechanism of the present invention.
FIG. 10 is a perspective view of the internal components present invention.
LIST OF REFERENCE NUMERALS
With regard to reference numerals used, the following numbering is used throughout the drawings.
10 Present Invention 12 Housing 14 Release Mechanism 16 Linkage 18 Hose Port 20 Upper Roller Guides 22 Lower Roller Guides 24 Brake Drum 26 Ratchet Mechanism 28 Block and Tackle 30 Upper Pulleys 32 Fixed Shaft 34 Lower Pulley 36 Moving Shaft 38 Cable 40 Guide Wheel 42 Guide Track 44 Guide Wheel Shaft 46 Hose 48 Spring 50 Brace 52 Cross Bar 54 Roller 56 Tooth 58 Fixing Plate 60 Through Hole 62 Nipple 64 Lifting Bar 66 Lower Extension 68 End Cap 70 Stop
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The following discussion describes in detail one embodiment of the invention (and several variations of that embodiment). This discussion should not be construed, however, as limiting the invention to those particular embodiments, practitioners skilled in the art will recognize numerous other embodiments as well. For definition of the complete scope of the invention, the reader is directed to appended claims.
FIG. 1 is an illustrative view of the present invention 10 in use. Shown is the present invention 10 being a storage device for a hose 46 having a system for a user to selectively pull a hose 46 out to a desired length and be selectively withdrawn back into said storage device by means of utilizing potential energy stored within a block and tackle mechanism 28 charged by the dispensing of pulling of the hose 46 out of the device.
FIG. 2 is a perspective view of the present invention 10 . Shown is the present invention 10 being a housing 12 for a hose 46 having an internal retracting mechanism powered by the storage of potential energy in a block and tackle mechanism 28 .
FIG. 3 is a perspective view of the internal components of the present invention 10 . Shown is the inside of the housing 12 of the present invention 10 depicting the internal components of the present invention 10 showing a set of upper roller guides 20 situated to be raised and lowered during the retraction and extension of hose 46 from the device by usage of a block and tackle mechanism 28 . The upper roller guides 20 are attached to a guide wheel shaft 44 . The guide wheel shaft 44 has ends that extend beyond left and right ends of the upper roller guides 20 . At each end of the guide wheel shaft 44 are guide wheels 40 , which are disposed in guide tracks 42 for guiding the vertical movement of the upper roller guides 20 . The housing 12 protects and supports the internal components. In addition to the upper roller guides there are lower roller guides 22 . The lower roller guides 22 are attached to the brake drum 24 . The brake drum 24 and its attached ratchet mechanism 26 prevent the hose 46 from being drawn back into the housing 12 until the user engages the release mechanism 14 . The release mechanism 14 causes the linkage 16 to move so that the linkage 16 no longer engages the ratchet mechanism 26 allowing the brake drum 24 to rotate so that the hose 46 is drawn back into the housing by the energy stored in the block and tackle mechanism 28 . The release mechanism 14 as seen in the FIG. 2 is a sliding switch. The switch would be biased into an engagement position by a spring or the like. This would ensure that the switch returns to and remains in an engagement position until the user desires to have the hose 46 drawn into the housing 12 . It is also contemplated that the release mechanism 14 could be a button that is depressed. This would also be biased into an engagement position.
FIG. 4 is a front view of the internal components of the present invention 10 in the wound position. Shown is a hose 46 held within the present invention in the wound or fully retracted position whereby the hose 46 is wound around a plurality of upper roller guides 20 and lower roller guides 22 each having a plurality of rollers 54 set apart at a gapping where said hose 46 is held in an oval like configuration whereby said oval configuration is pulled into being circular while the hose is withdrawn, said transition is utilized to store a potential energy gain gathered in a block and tackle mechanism 28 until selective release. The block and tackle mechanism 28 uses three pulleys, an attached spring, and a cable to provide energy storage. The two upper pulleys 30 are attached to a fixed shaft 32 . They are free to rotate about the shaft 32 but the shaft 32 is fixed in position so that it cannot move vertically or horizontally. The lower pulley 34 is attached to a moving shaft 36 . The moving shaft 36 has guide wheels 40 at each end where the guide wheels 40 are each set in a guide track 42 . This arrangement is similar to that of guide wheel shaft 44 which supports the upper or top roller guides. This allows the lower pulley 34 to rotate about the moving shaft 36 and the moving shaft 36 is provided with vertical movement. It is contemplated that the ends of the guide tracks 42 may be closed to prevent the guide wheels 40 from leaving the guide tracks 42 (see FIG. 4A ). The ends of the tracks could be closed by a metal end cap 68 . It is also contemplated that a stop 70 can be installed in the guide track 42 near or at the end (see FIG. 4B ). These will prevent the guide wheels 40 from leaving the guide tracks 42 . The stop can be a strip of metal that is secured across the slot in track. A cable 38 connects the upper roller guides 20 , the spring 48 , and the lifting bar 64 as seen in this figure. One end of the cable 38 is attached to the spring 48 and from there the cable 38 extends vertically to the top left pulley on the fixed shaft 32 . The cable 38 wraps around the pulley and then extends downward toward the lower pulley 34 on the moving shaft 36 . The cable 38 wraps around the lower pulley 34 and then extends upward and through the right pulley on the fixed shaft 32 . The cable 38 then extends over two additional pulleys guiding it to the lifting bar 64 . This end of the cable 38 is fixed or attached to the lifting bar 64 . The lifting bar 64 supports the guide wheel shaft 44 , which holds the upper roller guides 20 . The guide wheel shaft 44 can be joined to the lifting bar 64 in many ways. The ends of the lifting bar 64 can be welded to the guide wheel shaft 44 . It is also contemplated that the guide wheel shaft 44 will be disposed in through holes near the ends of the lifting bar 64 . The top or upper roller guides 20 are angled with respect to the fixed or lower roller guides 22 to improve the continuity of the hose 46 spooling from the upper roller guides 20 to the lower roller guides 22 .
FIG. 5 is a front view of the internal components of the present invention 10 in the partially unwound position. The upper roller guides 20 have moved toward the lower roller guides 22 causing the spring 48 to be extended by the cable 38 pulling up on the lower pulley 34 . The lower pulley 34 has moved upwards while the top roller guides 20 have moved downwards. When the user actuates the release mechanism 14 the energy stored in the block and tackle mechanism 28 causes the upper roller guides 20 to move upwards vertically causing the hose to be drawn into the housing 12 . The lower roller guides 22 have an extra row of rollers 54 so as to allow the hose 46 to extend out of the housing 12 so that the hose 46 can be connected to a hose bib to supply the hose 46 with water. It is also contemplated that the hose 46 can be connected to a nipple 62 , which is secured to the housing 12 . The nipple 62 would be threaded at both ends to allow for hose connections. The end of the nipple 62 which is inside the housing 12 would be provided with a male thread for connecting to the female end of the hose 46 . The end of the nipple 62 outside of the housing 12 could be provided with a have a female hose coupling to allow connection to the male end of a hose 46 . The coupling would be the same that is used on the female end of a garden hose. It is also contemplated that the nipple 62 may be threaded at both ends with male threads (see FIG. 5A ). In this case a connection hose with two female ends could be provided with the device so that the device can be connected to a hose bib. FIG. 5 shows there being seven rows of rollers on the top roller guides 20 and eight rows of rollers on the lower or bottom roller guides 22 . It is envisioned that there can be a lesser number of rows or a greater number of rows depending on how much hose 46 is to be stored in the device. It is also contemplated that the upper roller guides 20 and the lower roller guides 22 could be spaced further apart from each other to a greater length of hose 46 in the housing 12 . Increasing the number of rows allows for the height of the housing to be shortened while still retaining the same length of hose 46 . Each of the rows of the upper and lower roller guides are made up of a plurality of rollers attached to two semicircular braces 50 joined by cross bars 52 as seen in FIGS. 6 and 7 .
FIG. 6 is a top and side view of the one of the rows of the lower roller guides 22 of the present invention 10 . Each row is made up of a plurality of rollers 54 configured evenly about a two semicircular braces 50 . The rollers 54 can be attached to the braces 50 in a variety of ways. They may be secured with rivets, threaded screws, threaded bolts or the like. The rollers 54 will be attached so that they are provided with free rotational movement to so that the hose 46 can travel smoothly and easily along its path. It is contemplated that the rollers 54 may have a central through hole through which a shaft extends. The shafts could be fixed to one of the braces 50 and extend into a hole in the other brace 50 providing for the desired alignment. The cross bars 42 ensure the proper spacing of the braces 50 . They also provide reinforcement to the braces 50 . The rollers 54 may be mounted directly to the shafts in the case that the rollers 54 are made of a plastic such as nylon. The plastic of the rollers 54 can act as it own bearing providing the smooth and free rotational movement about the shaft. It is also contemplated that bearings can be employed between the rollers 54 and the shafts. These bearing could be sealed and pre lubricated. These could be of the type used in inline skate wheels. The only requirement is to allow the hose 46 with free and smooth movement along its path.
FIG. 7 is a top and side view of one of the rows of the upper roller guides 20 of the present invention 10 . Each row is made up of a plurality of rollers 54 configured evenly about two semicircular braces 50 . The rollers 54 of the present invention 10 function to guide the hose 46 smoothly and easily to its path. The support braces 50 are angled to improve the continuity of the hose 46 spooling from upper roller guides 20 to the lower roller guides 22 . The rollers 54 of the upper roller guides 20 would be mounted the same as those in the lower roller guides 22 .
FIG. 8 is a perspective view of one of the rows of the lower roller guides 22 of the present invention 10 . Each row is made up of a plurality of rollers 54 configured evenly about two semicircular braces 50 including a plurality of crossbars 52 .
FIG. 9 is a perspective view of the ratchet mechanism 26 of the present invention. Shown is the ratchet mechanism 26 of the present invention utilized for retaining drawn lengths of hose 46 in a pulled state until released by the release mechanism 14 and the linkage 16 . When released the block and tackle mechanism 28 coupled to a spring 48 exert a pulling force to withdraw the pulled lengths of hose 46 .
FIG. 10 is a perspective view of the internal components of the present invention 10 . Shown is the inside of the housing 12 of the present invention depicting the internal components of the present invention 10 showing an upper set of roller guides 20 situated to be raised and lowered during the retraction and extension of hose 46 from the device by usage of a block and tackle mechanism 28 . Additionally shown is the present invention 10 having a ratchet mechanism 26 and a brake drum 24 utilized in retaining drawn lengths of hose 46 until selectively released by activating the release mechanism 14 . This figure shows that the lifting bar 64 may be connected to the outer braces 50 of the upper roller guides 20 instead of being joined to the guide wheel shaft 44 . The guide wheel shaft 44 can be joined to the upper or top roller guides 20 by a plurality of fixing plates 58 . A fixing plate 58 could be attached to each of the end braces 50 provide all the intermediate braces 50 are joined together. Intermediary fixing plates 58 could be employed between mating braces 50 to provide further support if required. It is also contemplated that the guide wheel shaft 44 could be positioned through all the braces 50 of the upper roller guides 20 to eliminate the need for fixing plates 58 . This could be accomplished by modifying the braces 50 with a lower extension 66 where the lower extension 66 has a through hole 60 to accept the guide wheel shaft 44 . This is seen in FIG. 8B . | The present invention discloses a device for dispensing and retrieving a length of hose. A housing contains upper and lower roller guides, a brake drum, a ratchet mechanism and a block and tackle assembly. As the hose is pulled out of the housing the upper roller guides move towards the lower roller guides and energy is stored in the block and tackle mechanism. The break drum and ratchet mechanism prevent the hose from being wound into the housing until the release mechanism is activated. One the release mechanism is activated the hose is wound into the housing by the energy stored in the block and tackle mechanism causing the upper roller guides to move away from the lower roller guides. |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 13/329,782, filed Dec. 19, 2011, which is a division of U.S. patent application Ser. No. 12/436,648, filed May 6, 2009.
BACKGROUND AND FIELD
This application relates to the use of sacrificial agents in cementitious mixtures containing ash including fly ash concrete, and to the resulting mixtures and compositions. More particularly, this application relates to sacrificial agents that reduce or eliminate the detrimental effects of ash such as fly ash on the air entrainment properties of cementitious mixtures.
The partial replacement of portland cement by fly ash is growing rapidly, driven simultaneously by more demanding performance specifications on the properties of concrete and by increasing environmental pressures to reduce portland cement consumption. Fly ash can impart many beneficial properties to concrete such as improved rheology, reduced permeability and increased later-age strength; however, it also may have a negative influence an bleed characteristics, setting time and early strength development. Many of these issues can be managed by adjusting mixture proportions and materials, and by altering concrete placement and finishing practices. However, other challenging problems encountered when using certain fly ash are not always easily resolved. The most important difficulties experienced when using fly ash are most often related to air entrainment in concrete.
Air entrained concrete has been utilized in the United States since the 1930's. Air is purposely entrained in concrete, mortars and grouts as a protective measure against expansive forces that can develop in the cement paste associated with an increase in volume resulting from water freezing and converting to ice. Adequately distributed microscopic air voids provide a means for relieving internal pressures and ensuring concrete durability and long term performance in freezing and thawing environments. Air volumes (volume fraction) sufficient to provide protective air void systems are commonly specified by Building Codes and Standard Design Practices for concrete which may be exposed to freezing and thawing environments. Entrained air is to be distinguished from entrapped air (air that may develop in concrete systems as a result of mixing or the additions of certain chemicals). Entrained air provides an air void system capable of protecting against freeze/thaw cycles, while entrapped air provide no protection against such phenomena.
Air is also often purposely entrained in concrete and other cementitious systems because of the properties it can impart to the fresh mixtures. These can include: improved fluidity, cohesiveness, improved workability and reduce bleeding.
The air void systems are generated in concrete, mortar, or paste mixtures by introducing air entrainment admixtures (referred to as air entrainment agents or air-entraining agents) which are a class of specialty surfactants. When using fly ash, the difficulties in producing air-entrained concrete are related to the disruptive influence that some fly ashes have on the generation of sufficient air volumes and adequate air void systems. The primary influencing factor is the occurrence of residual carbon, or carbonaceous materials (hereafter designated as fly ash-carbon), which can be detected as a discrete phase in the fly ash, or can be intimately bound to the fly ash particles. Detrimental effects on air entrainment by other fly ash components may also occur, and indeed air entrainment problems are sometimes encountered with fly ash containing very low amounts of residual carbon.
Fly ash-carbon, a residue of incomplete coal or other hydrocarbon combustion, is in many ways similar to an “activated carbon.” For example, like activated carbon, fly ash-carbon can adsorb organic molecules in aqueous environments. In cement paste containing organic chemical admixtures, the fly ash-carbon can thus adsorb part of the admixture, interfering with the function and performance of the admixture. The consequences of this adsorption process are found to be particularly troublesome with air entrainment admixtures (air entrainment agents) which are commonly used in only very low dosages. In the presence of significant carbon contents (e.g. >2 wt %), or in the presence of low contents of highly reactive carbon or other detrimental fly ash components, the air entrainment agents may be adsorbed, interfering with the air void formation and stability; this leads to tremendous complications in consistently obtaining and maintaining specified concrete air contents.
To minimize concrete air entrainment problems, ASTM guidelines have limited the fly ash carbon content to less than 6 wt %. Other institutions such as AASHTO and state departments of transportation have more stringent limitations. Industry experience indicates that, in the case of highly active carbon (for example, high specific surface area), major interferences and problems can still be encountered, even with carbon contents lower than 1 wt %.
Furthermore, recent studies indicate that, while fly ash carbon content, as measured by loss on ignition (LOI) values, provides a primary indicator of fly ash behavior with respect to air entrainment, it does not reliably predict the impact that a fly ash will have on air entrainment in concrete. Therefore, there currently exist no means, suitable for field quality control, capable of reliably predicting the influence that a particular fly ash sample will have on air entrainment, relative to another fly ash sample with differing LOI's, sources, or chemistries. In practice, the inability to predict fly ash behavior translates into erratic concrete air contents, which is currently the most important problem in fly ash-containing concrete.
Variations in fly ash performance are important, not only because of their potential impact on air entrainment and resistance to freeze thaw conditions, but also because of their effects related to concrete strength. Just as concrete is designed according to building standards for a particular environment, specifications are also provided for physical performance requirements. A common performance requirement is compressive strength. An increase in entrained air content can result in a reduction in compressive strength of 3-6% for each additional percentage of entrained air. Obviously, variations in fly ash-carbon, which would lead to erratic variations in air contents, can have serious negative consequences on the concrete strength.
The fly ash-carbon air entrainment problem is an on-going issue that has been of concern since fly ash was first used nearly 75 years ago. Over the past ten years, these issues have been further exacerbated by regulations on environmental emissions which impose combustion conditions yielding fly ash with higher carbon contents. This situation threatens to make an increasingly larger portion of the available fly ash materials unsuitable for use in concrete. Considering the economic impact of such a trend, it is imperative to develop practical corrective schemes that will allow the use, with minimal inconvenience, of fly ash with high carbon contents (e.g., up to 10 wt %) in air-entrained concrete.
Air entrainment in fly ash-concrete may become yet more complicated by pending regulations that will require utilities to reduce current mercury (Hg) emissions by 70-90%. One of the demonstrated technologies for achieving the Hg redaction is the injection of activated carbon into the flue gas stream after combustion so that volatile Hg is condensed on the high surface area carbon particles and discarded with the fly ash. Current practices are designed such that the added activated carbon is generally less than 1% by mass of the fly ash, but preliminary testing indicates this is disastrous when using the modified fly ash in air-entrained concrete.
The origin of air entrainment problems in fly ash concrete, and potential approaches to their solution, have been the subject of numerous investigations. Most of these investigations focused on the “physical” elimination of the carbon by either combustion processes, froth floatation, or electrostatic separation. To date, the proposed fly ash treatment approaches have found limited application due to their inherent limitations (e.g., separation techniques have limited efficiency in low carbon fly ash; secondary combustion processes are most suitable for very high carbon contents), or due to their associated costs.
“Chemical” approaches have also been proposed to alleviate carbon-related problems in concrete air entrainment, for example through the development of alternative specialty surfactants for air entrainment agents such as polyoxyethylene-sorbitan oleate as an air entrainment agent (U.S. Pat. No. 4,453,978). Various other chemical additives or fly ash chemical treatments have been proposed, namely:
the addition of inorganic additives such as calcium oxide or magnesium oxide (U.S. Pat. No. 4,257,815); this patent prescribes the use of inorganic additives which may influence other properties of fresh mortars or concrete, for example, rate of slump loss and setting time; the addition of C8 fatty acid salts (U.S. Pat. No. 5,110,362); the octanoate salt is itself a surfactant, and it is said to “stabilize the entrained air and lower the rate of air loss” (Claim 1 of U.S. Pat. No. 5,110,362); the use of a mixture of high-polymer protein, polyvinyl alcohol and soap gel (U.S. Pat. No. 5,654,352); this discloses the use of protein and polyvinyl alcohol, and optionally a colloid (for example, bentonite) to formulate air entrainment admixtures; treatment with ozone (U.S. Pat. No. 6,136,089); the ozone oxidizes fly ash-carbon, reducing its absorption capacity for surfactants and thus making the fly ash more suitable for use in air entrained systems.
None of these proposed solutions have found significant acceptance in the industry, either because of their complexity and cost, or because of their limited performance in actual use. For example, a clear limitation to the addition of a second surfactant (e.g., C8 fatty acid salt), to compensate for the adsorption of the air entrainment agents surfactant, simply shifts the problem to controlling air content with a combination of surfactants instead of a single one. The problem of under- or over-dosage of a surfactant mixture is then the same as the problem discussed above with conventional air entrainment agents.
Hence, a practical solution is needed for efficiently relieving air entrainment problems for a wide variety of fly ash materials and for other ashes, in ready mix facilities or in the field.
SUMMARY
The methods and compositions described herein facilitate the formation of cementitious mixtures containing fly ash and other combustion ashes, and solid products derived therefrom. Further, these methods and compositions facilitate air entrainment into such mixtures in a reliable and predictable fashion.
According to some embodiments, there is provided a method of reducing or eliminating the effect of fly ash or other combustion ashes or air-entrainment in an air-entraining cementitious mixture containing fly ash or another combustion ash, comprising the steps of: forming a cementitious mixture comprising water, cement, fly ash or another combustion ash, (and optionally other cementitious components, sand, aggregate, etc.) and an air entrainment agent (and optionally other concrete chemical admixtures); and entraining air in the mixture; wherein an amount of at least one sacrificial agent is also included in the cementitious mixture in at least an amount necessary to neutralize the detrimental effects of components of said fly ash or other combustion ash on air entrainment activity, the sacrificial agent comprising a material or mixture of materials that, when present in the same cementitious mixture without fly ash or the other combustion ash in said amount, causes less than 2 vol. % additional air content in the cementitious mixture.
The amount of the sacrificial agent used in the cementitious mixture can, in some embodiments, exceed the amount necessary to neutralize the detrimental effects of the components of the fly ash or other combustion ash. Thus, if the fly ash varies in content of the detrimental components from a minimum content to a maximum content according to the source or batch of the fly ash or other combustion ash, the amount of the at least one sacrificial agent can exceed the amount necessary to neutralize the detrimental effects of the components of the fly ash when present at their maximum content.
The sacrificial agent is a primary amine, secondary amine, or tertiary amine compound, or any combination thereof. The sacrificial agent can be a compound selected from the group consisting of the structure NR 1 R 2 R 3 . R 1 is substituted or unsubstituted non-alkoxylated C 5-22 alkyl, substituted of unsubstituted non-alkoxylated C 5-22 alkenyl, substituted or unsubstituted non-alkoxylated C 5-22 alkynyl, substituted or unsubstituted C 2-22 alkoxylated alkyl, substituted or unsubstituted C 2-22 alkoxylated alkenyl, or substituted or unsubstituted C 2-22 alkoxylated alkynyl. R 2 and R 3 are each independently selected from hydrogen, substituted or unsubstituted C 1-22 alkyl, substituted or unsubstituted C 2-22 alkenyl, or substituted or unsubstituted C 2-22 alkynyl. R 2 and R 3 can be optionally alkoxylated. One or more of R 1 , R 2 , or R 3 can be an alkoxylated or non-alkoxylated, substituted or unsubstituted, fatty acid residue. The fatty acid residues can be saturated fatty acid residues, monounsaturated fatty acid residues, polyunsaturated fatty acid residues, or mixtures thereof. In some embodiments, one or more of R 1 , R 2 , and R 3 can be amino-substituted including NR 4 R 5 as a substituent. For example, the sacrificial agent can be polyoxypropylenediamine or triethyleneglycol diamine. In some embodiments, the sacrificial agent is an alcoholamine. In some embodiments, the sacrificial agent is a mixture of two or more compounds. In some embodiments, the HLB value of the sacrificial agent or the mixture of sacrificial agents is in the range of 5 to 20 (e.g., 4 to 18). In some embodiments, the Log K ow for the sacrificial agent can be in the range of −3 to +2 (e.g. −2 to +2).
In some embodiments, the sacrificial agent is a compound selected from tridodecylamine, dodecyldimethylamine, octadecyldimethylamine, cocoalkyldimethylamine, hydrogenated tallowalkyldimethylamines, oleyldimethylamine, dicocoalkylmethylamine, N-oleyl-1,1′-iminobis-2-propanol, N-tallowalkyl-1,1′-iminobis-2-propanol, polyoxypropylenediamine, triethyleneglycol diamine, and mixtures thereof. In some embodiments, the sacrificial agent includes dodecyldimethylamine. In some embodiments, the sacrificial agent includes one or more compounds selected from N-oleyl-1,1′-iminobis-2-propanol and N-tallowalkyl-1,1′-iminobis-2-propanol. In some embodiments, the sacrificial agent includes a polyetheramine.
The dosage, or amount, of the sacrificial agent can vary from 0.005% to 5% by weight based on the weight of the fly ash or other combustion ash. In some embodiments, the amount is from 0.01 to 2%, 0.02-1% and 0.05-0.5% (e.g. 0.1-0.3%) by weight based on the weight of the fly ash or other combustion ash. The sacrificial agent can be added directly to the fly ash by pre-treating the fly ash or can be added to the cementitious composition or with other components of the cementitious composition.
Typically, the fly ash or other combustion ash is provided in the cementitious composition in an amount of from 5% to 55% by weight of the total amount of cementitious materials in the cementitious composition (cement and fly ash or other combustion ash), depending on the type and composition of the fly ash or other combustion ash. In some embodiments, the amount of fly ash or other combustion ash is from 10% to 50% or 15% to 30% by weight (e.g. 25% by weight) of the total, amount of cementitious materials in the cementitious composition.
The sacrificial agent can be mixed with the air entrainment agent prior to mixing the sacrificial agent and air entrainment agent with the fly ash or other combustion ash, cement, and water. Alternatively, the sacrificial agent can be mixed with the fly ash or other combustion ash prior to mixing the sacrificial agent and the fly ash or other combustion ash with the cement, water, and the air entrainment agent. In the latter case, the sacrificial agent can be added to the fly ash or other combustion ash by spraying a liquid containing the sacrificial agent onto the fly ash or other combustion ash, or by mixing a spray-dried solid sacrificial agent formulation with the fly ash or other combustion ash. Suitable methods are described in published U.S. Patent Application No. US 2004/0144287, which is hereby incorporated by reference in its entirety. Alternatively, the sacrificial agent can be added after the fly ash or other combustion ash, cement, water, and air entrainment agent have been mixed together. In some embodiments, an additional material selected from sand, aggregate, concrete modifier, and combinations thereof, can be incorporated into the mixture.
In some embodiments, the cementitious mixture can be formed by mixing an amount of the sacrificial agent with the fly ash or other combustion ash to form a pre-treated fly ash or other combustion ash, and then mixing the pre-treated fly ash or other combustion ash with the water, air entrainment agent and cement. In some embodiments, the cementitious mixture is formed by mixing the air entrainment agent and the sacrificial agent to form a component mixture, and then mixing the component mixture with the water, fly ash or other combustion ash and cement, and entraining the air in the mixture. In some embodiments, water, cement, fly ash or other combustion ash, air entrainment agent and sacrificial agent are mixed together simultaneously while entraining the air in the mixture. In some embodiments, the sacrificial agent is mixed with the water, cement and fly ash or other combustion ash before the air entrainment agent is added. In some embodiments, the sacrificial agent is mixed with the water, cement, and fly ash or other combustion ash at the same time as the air entrainment agent.
In some embodiments, the fly ash or other combustion ash consists essentially of fly ash. In some embodiments, the fly ash or other combustion ash comprises a blend of fly and another combustion ash. In some embodiments, the sacrificial agent, when present in the same cementitious mixture without fly ash or the other combustion ash in the appropriate amount causes less than 1 vol. % additional air content in the cementitious mixture.
In some embodiments, the method further includes the step of selecting a sacrificial agent including a material or mixture of materials to reduce or eliminate the effect of fly ash or another combustion ash on air entrainment in a cementitious mixture and selecting an amount of the sacrificial agent such that the amount is at least an amount necessary to neutralize the detrimental effects of components of the fly ash on air entrainment activity and the amount of sacrificial agent causes less than 2 vol. % additional air content in the same cementitious mixture without fly ash or the other combustion ash. In some embodiments, the fly ash or other combustion ash has a predetermined maximum carbon content and the amount of sacrificial agent exceeds the amount necessary to neutralize the maximum carbon content in the fly ash or other combustion ash. In some embodiments, the sacrificial agent amount used does not result in a substantial increase in air entrainment compared to providing the sacrificial agent in an amount necessary to neutralize the detrimental effects of components of the fly ash on air entrainment activity. In some embodiments, the sacrificial agent causes less than 2 vol. % additional air content in the cementitious mixture without fly ash. In some embodiments, the components to be neutralized are carbon content.
There is also provided a method of reducing or eliminating the effect of fly ash on air entrainment in an air-entraining cementitious mixture, comprising the steps of: forming a cementitious mixture comprising water, cement, fly ash, and an air entrainment agent, and entraining air in the mixture; wherein a sacrificial agent is also included in the cementitious mixture in at least the amount necessary to neutralize the detrimental effects of the carbon content of said fly ash on air entrainment activity, the sacrificial agent comprising a material or mixture of materials that, when present in the same cementitious mixture without fly ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture.
There is further provided a method of addressing the variance of carbon content in fly ash used in cementitious compositions to provide a cementitious composition with a substantially constant level of air entrainment, comprising: forming a cementitious mixture comprising water, cement, fly ash, an air entrainment agent, and a sacrificial agent and entraining air in the mixture, wherein the fly ash has a maximum carbon content; and selecting a sacrificial agent for the cementitious mixture and an amount of the sacrificial agent such that the amount of the sacrificial agent exceeds the amount necessary to neutralize the maximum carbon contest in the fly ash, wherein the sacrificial agent comprises a material or mixture of materials that, when present in the same cementitious mixture without fly ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture.
Furthermore, a method of pre-treating fly ash or another combustion ash to reduce or eliminate the effect the fly ash or the other combustion ash has on air entrainment in an air-entraining cementitious mixture comprising the fly ash or other combustible fly ash and an air-entraining agent is provided, the method comprising: mixing a sacrificial agent with fly ash or another combustion ash to form a pre-treated ash, wherein the sacrificial agent is combined with the fly ash or the other combustion ash in at least an amount necessary to neutralize the detrimental effects of components of the fly ash or the other combustion ash on air entrainment activity in the air-entraining cementitious mixture, the sacrificial agent comprising a material or mixture of materials that, when present in a cementitious mixture without fly ash or another combustion ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture.
There is also provided a method of addressing the variance of carbon content in fly ash used in cementitious compositions to provide a cementitious composition with a substantially constant level of air entrainment, comprising: selecting a sacrificial agent and an amount of the sacrificial agent such that the amount of the sacrificial agent exceeds the amount necessary to neutralize the maximum carbon content in the fly ash, mixing the sacrificial agent with fly ash or another combustion ash to form a pre-treated ash, wherein the sacrificial agent is combined with the fly ash or the other combustion ash in at least an amount necessary to neutralize the detrimental effects of components of the fly ash or the other combustion ash on air entrainment activity in the air-entraining cementitious mixture, the sacrificial agent comprising a material or mixture of materials that, when present in a cementitious mixture without fly ash or another combustion ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture
Also provided herein is a composition comprising fly ash or another combustion ash that reduces or eliminates the effect the fly ash or the other combustion ash has on air entrainment in an air-entraining cementitious mixture comprising the fly ash or the other combustion ash and an air-entraining agent, the composition comprising fly ash or another combustion ash and a sacrificial agent, the sacrificial agent present in at least an amount necessary to neutralize the detrimental effects of components of the fly ash or the other combustion ash on air entrainment activity in the air-entraining cementitious mixture, the sacrificial agent comprising a material or mixture of materials that, when present in a cementitious mixture without fly ash or another combustion ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture.
Also provided herein is a composition that addresses the variance of carbon content in fly ash or another combustion ash used in cementitious compositions to provide a cementitious composition with a substantially constant level of air entrainment, comprising fly ash or another combustion ash and a sacrificial agent, the sacrificial agent present in at least an amount necessary to neutralize the detrimental effects of components of the fly ash or the other combustion ash on air entrainment activity in the air-entraining cementitious mixture, the sacrificial agent comprising a material or mixture of materials that, when present in a cementitious mixture without fly ash or another combustion ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture.
Also provided herein is an air-entraining cementitious mixture comprising fly ash or another combustion ash that reduces or eliminates the effect the fly ash or other combustion ash has on air entrainment in the air-entraining cementitious mixture; the air-entraining cementitious mixture comprising air, water, cement, fly ash, an air entrainment agent and a sacrificial agent, wherein the sacrificial agent is present in at least an amount necessary to neutralize the detrimental effects of components of the fly ash or the other combustion ash on air entrainment activity in the air-entraining cementitious mixture, the sacrificial agent comprising a material or mixture of materials that, when present in a cementitious mixture without fly ash or another combustion ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture.
Further provided herein is an air-entraining cementitious mixture comprising fly ash or another combustion ash that addresses the variance of carbon content in fly ash used in cementitious compositions to provide a cementitious composition with a substantially constant level of air entrainment, the air-entraining cementitious mixture comprising air, water, cement, fly ash, an air entrainment agent and a sacrificial agent, wherein the sacrificial agent is present in at least an amount necessary to neutralize the detrimental effects of components of the fly ash or the other combustion ash on air entrainment activity in the air-entraining cementitious mixture, the sacrificial agent comprising a material or mixture of materials that, when present in a cementitious mixture without fly ash or another combustion ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture, wherein the sacrificial agent is present in at least an amount necessary to neutralize the detrimental effects of components of the fly ash or the other combustion ash on air entrainment activity in the air-entraining cementitious mixture, the sacrificial agent comprising a material or mixture of materials that, when present in a cementitious mixture without fly ash or another combustion ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture.
Also provided herein is an air-entrained hardened cementitious mass comprising fly ash or another combustion ash that reduces or eliminates the effect the fly ash or other combustion ash has on air entrainment in the air-entrained hardened cementitious mass, the air-entrained hardened cementitious mass comprising air, cement, fly ash, an air entrainment agent and an amount of a sacrificial agent, wherein the sacrificial agent is present in at least an amount necessary to neutralize the detrimental effects of components of the fly ash or the other combustion ash on air entrainment activity in the air-entraining cementitious mixture, the sacrificial agent comprising a material or mixture of materials that, when present in a cementitious mixture without fly ash or another combustion ash in said amount causes less than 2 vol. % additional air content in the cementitious mixture.
As described herein, the sacrificial agents can be used to eliminate or drastically reduce air entrainment problems encountered in concrete containing fly ash. Such additives, or combinations of such additives, can be added before (e.g. in the fly ash material), during, or after the concrete mixing operation. The use of these materials can have the following advantages. They:
enable adequate levels (typically 5-8 vol. %) of gas, normally air, to be entrained in concrete or other cementitious products, with dosages of conventional air entrainment agents that are more typical of those required when no fly ash, or fly ash with low carbon content, is used; confer predictable air entrainment behavior onto fly ash-concrete regardless of the variability in the fly ash material, such as the source, carbon content, chemical composition; do not interfere with cement hydration and concrete set time; do not alter other physical and durability properties of concrete; do not significantly alter their action in the presence of other concrete chemical admixtures, for example, water reducers, superplasticizers and set accelerators; and do not cause detrimental effects when added in excessive dosages, such as excessive air contents, extended set times, or strength reduction.
The acceptability of “overdosage” of these sacrificial agents is advantageous in some embodiments, since large fluctuations in fly ash properties (carbon content, reactivity, etc.) can be accommodated by introducing a moderate excess of these sacrificial agents without causing other problems. This provides operators with a substantial trouble-free range or comfort zone.
The cementitious mixtures can contain conventional ingredients such as sand and aggregate, as well as specific known additives.
DEFINITIONS
The term “fly ash”, as defined by ASTM C 618 (Coal Fly Ash or Calcined Natural Pozzolan For Use in Concrete) refers to a by product of coal combustion. However, other combustion ashes can be employed which are fine ashes or flue dusts resulting from co-firing various fuels with coal, or resulting from the combustion of other fuels that produce an ash having pozzolanic qualities (the ability to form a solid when mixed with water and an activator such ash lime or alkalis) or hydraulic qualities (the ability to form a solid when mixed with water and set). The ash itself has pozzolanic/hydraulic activity and can be used as a cementitious material to replace a portion of portland cement in the preparation of concrete, mortars, and the like. The term “fly ash and other combustion ash” as used herein includes:
1) Ash produced by co-firing fuels including industrial gases, petroleum coke, petroleum products, municipal solid waste, paper sludge, wood, sawdust, refuse derived fuels, switchgrass or other biomass material, either alone or in combination with coal. 2) Coal ash and/or alternative fuel ash plus inorganic process additions such as soda ash or trona (native sodium carbonate/bicarbonate used by utilities). 3) Coal ash and/or alternative fuel ash plus organic process additives such as activated carbon, or other carbonaceous materials, for mercury emission control. 4) Coal ash and/or alternative fuel ash plus combustion additives such as borax. 5) Coal ash and/or alternative fuel gases plus flue gas or fly ash conditioning agents such as ammonia, sulfur trioxide, phosphoric acid, etc.
The term “fly ash concrete” means concrete containing fly ash and portland cement in any proportions, but optionally additionally containing other cementitious materials such as blast furnace slag, silica fume, or fillers such as limestone, etc.
The term “surfactants” is also well understood in the art to mean surface active agents. These are compounds that have an affinity for both fats (hydrophobic) and water (hydrophilic) and so act as foaming agents (although some surfactants are non-foaming, e.g. phosphates), dispersants, emulsifiers, and the like, e.g. soaps.
The term “air entrainment agent” (AEA) means a material that results in a satisfactory amount of air being entrained into a cementitious mixture, e.g. 5-9 vol % air, when added to a cementitious formulation. Generally, air entrainment agents are surfactants (i.e. they reduce the surface tension when added to aqueous mixtures), and are often materials considered to be soaps.
The mode of action of air entrainment agents, and the mechanism of air void formation in cementitious mixtures are only poorly understood. Because of their influence on the surface tension of the solution phase, the surfactant molecules are believed to facilitate the formation of small air cavities or voids in the cementitious paste, by analogy to formation of air ‘bubbles’. It is also believed that the wall of these voids are further stabilized through various effects, such as incorporation into the interfacial paste/air layer of insoluble calcium salts of the surfactants, or of colloidal particles.
The performance of surfactants as concrete air entrainment admixture depends on the composition of the surfactant; the type of hydrophilic group (cationic, anionic, zwitterionic, or non-ionic), the importance of its hydrophobic residue (number of carbon groups, molecular weight), the chemical nature of this residue (aliphatic, aromatic) and the structure of the residue (linear, branched, cyclic), and on the balance between the hydrophilic and lipophilic portions of the surfactant molecule (HLB). Cationic and non-ionic surfactants are reported to entrain more air than anionic surfactants because the latter are often precipitated as insoluble calcium salts in the paste solution; however, the stability of the air void has also been reported to be greater with anionic surfactant than with cationic or non-ionic surfactants. Typical examples of compounds used as surface active agents are sodium salts of naturally occurring fatty acid such as tall oil fatty acid, and sodium salts of synthetic n-alkylbenzene sulfonic acid. Common concrete air entrainment (or air-entraining) agents include those derived from the following anionic surfactants: neutralized wood resins, fatty acids salts, alkyl-aryl sulfonates, and alkyl sulfates.
The term “sacrificial agent” (SA) means a material, or a mixture of materials, that interacts with (and/or neutralizes the detrimental effects of) components of fly ash that would otherwise interact with an air entrainment agent and reduce the effectiveness of the air entrainment agent to incorporate air (or other gas) into the cementitious mixture. The sacrificial agents are not “air entrainment agents” as they are understood in the art and, in the amounts used in the cementitious mixture, do not cause more than 2 vol % additional air content (or even less than 1 vol % additional air content) into the same mixture containing no fly ash. In some embodiments, the sacrificial agent, in the amounts employed in fly ash-containing mixtures, is responsible for introducing less than 0.5 vol % or even substantially no additional air content into the same mixture containing no fly ash. In some embodiments, the sacrificial agent neither promotes nor inhibits the functioning of the air entrainment agent compared with its functioning in a similar mixture containing no fly ash.
The term “cementitious mixture” means a mixture such as concrete mix, mortar, paste, grout, etc., that is still in castable form and that, upon setting, develops into a hardened mass suitable for building and construction purposes. Likewise, the term “cement” means a product (other than fly ash) that is capable of acting as the principal hardenable ingredient in a cementitious mixture. In some embodiments, the cement is portland cement, but at least a portion can include blast furnace slag, gypsum, and the like.
The term “percent” or “%” as used herein in connection with a component of a composition means percent by weight based on the cementitious components (cement and fly ash) of a cementitious mixture (unless otherwise stated). When referring to air content, the term % means percent by volume or vol %.
The terms “alkyl”, “alkenyl”, and “alkynyl” as used herein can include straight-chain and branched monovalent substituents. Examples include methyl, ethyl, isobutyl, 2-propenyl, 3-butynyl and the like.
The term, “substituted” as used herein indicates the main substituent has attached to it one or more additional components, such as, tor example, amino, hydroxyl, carbonyl, or halogen groups. The term “unsubstituted” indicates that the main substituent has a full compliment of hydrogens, i.e., commensurate with its saturation level, with no substitutions, e.g., linear decane (—(CH 2 ) 9 —CH 3 ).
The term “alkoxylated” as used herein is an adjective referring to a compound having an “alkoxyl” linkage having the formula —(OR) n — wherein R can be an alkyl, alkenyl, or alkynyl group. Examples of suitable “R” groups include ethyl (ethoxylate), propyl (propoxylate), or butyl (butoxylate) groups. The value for n is an average value and can vary for the sacrificial agent (where alkoxylation is present) from 1 to 10, 1.5 to 9 or 2 to 8.
ABBREVIATIONS
Fly Ash
FA
Portland cement A
PCA
Portland cement C
PCC
Sacrificial agent
SA
Air entrainment agents or admixtures
AEA
Relative to cementitious materials (CM)
wt %
Amount of air entrained
vol %
Average of Air Entrained
Aver (%)
Relative Standard Deviation
RSD (%)
HLB
Hydrophilic Lipophilic Balance
K ow
Ratio of solubility in oil
(octanol) and in water
LogK ow
Logarithm of K ow
LOI
Loss on ignition
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph illustrating competitive absorption by activated carbon with various sacrificial agents at saturated concentrations.
FIG. 2 is a graph illustrating the percentage of air in concrete with increasing concentrations of an air entrainment agent with various activated carbon samples at varying amounts.
FIG. 3 is a graph illustrating the dosage of an air entrainment agent at 6% air in concrete with increasing amounts of carbon contents.
FIG. 4 is a graph illustrating the percentage of air in concrete with increasing concentrations of an air entrainment agent with various amounts of activated carbon.
FIG. 5 is a graph illustrating the percentage of air in concrete with increasing concentrations of an air entrainment agent with sacrificial agents and activated carbon.
FIG. 6 is a graph illustrating the percentage of air in concrete with increasing concentrations of an air entrainment agent with sacrificial agent-treated fly ash combined with activated carbon.
FIG. 7 is a graph illustrating the percentage of air in concrete with increasing concentrations of an air entrainment agent with sacrificial agent-treated fly ash with and without activated carbon.
FIG. 8 is a graph illustrating the percentage of air in concrete with increasing percentages of activated carbon in the presence of an air entrainment agent and with and without sacrificial agents.
FIG. 9 is a graph illustrating the percentage of air in concrete with increasing concentrations of an air entrainment agent with and without sacrificial agents.
FIG. 10 is a graph illustrating the percentage of air in concrete with increasing concentrations of an air entrainment agent with concrete friendly activated carbon and varying quality fly ash samples.
FIG. 11 is a graph illustrating the percentage of air in concrete with increasing concentrations of an air entrainment agent with high and poor quality fly ash, concrete friendly activated carbon, and sacrificial agents.
DETAILED DESCRIPTION
In the following description, reference is made to air entrainment in concrete and cementitious mixtures. It will be realized by persons skilled in the art that other inert gases, such as nitrogen, that act in the same way as air, can be entrained in concrete and cementitious mixtures. The use of air rather than other gases is naturally most frequently carried out for reasons of simplicity and economy. Techniques for entraining air in cementitious mixtures using air-entraining agents are well known to persons skilled in the art. Generally, when an air entrainment agent is used, sufficient air is entrained when the ingredients of the mixture are simply mixed together and agitated in conventional ways, such as stirring or tumbling sufficient to cause thorough mixing of the ingredients.
As noted earlier, air entrainment problems in fly ash concrete have been traced to undesirable components contained in the fly ash materials, particularly residual carbon. These fly ash components can adsorb and/or react or interact with the air entrainment agent (surface active compounds, e.g. soaps) used for entrainment air in concrete, thereby neutralizing or diminishing the functionality of such agents and consequently reducing the uptake of air. Up to the present, the industrial approach to dealing with these air entrainment problems consisted in adding higher dosages of the air entrainment agents in order to overwhelm the deleterious processes. Because the quantities of detrimental components in fly ash can vary greatly among fly ashes from different sources, or for a fly ash from any particular source at different times, the current practices lead to other complications, namely in assessing the adequate dosage of air entrainment agents to achieve a specified air content, in maintaining the specified air content over adequate time periods, in guarding against excessive entrained air contents that would detrimentally impact concrete strength and durability, in obtaining specified air void parameters, etc. In particular, the fact that excessive dosages of the air entrainment agent can result in excess air entrainment and subsequent reduction in concrete compressive strength, is particularly serious and a major disadvantage of the prior approach.
The issues with the components of fly ash and other combustion ash and the effects of these components on air entrainment are further complicated by the addition of activated carbon to fly ash and other combustion ashes. Specifically, mercury (Hg) is present as a trace element in coal that becomes a contaminant in fly ash from coal-fired power plants and other coal fired furnaces. As a result, processes have been developed to capture Hg contained in fly ash. For example, one process that has been developed injects activated carbon in fly ash to absorb Hg. Unfortunately, activated carbon is expensive and thus its use for Hg removal adds significantly to overall costs. Fly ash without activated carbon may be used as a partial replacement for portland cement in concrete if it meets certain specifications (such as those found in ASTM C618-05 “Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete”). The most common reason fly ash without activated carbon cannot be used in concrete is excess unburned carbon content in the ash. Excess unburned carbon is not allowed because it absorbs additives used in concrete making and makes them ineffective. However, after addition of activated carbon for Hg capture, ash is generally unusable even if it meets the unburned carbon specifications. This is because the activated carbon absorbs the concrete additives to a much large degree than the unburned carbon normally found in fly ash. Therefore, adding activated carbon to fly ash to capture Hg requires additional thermal beneficiation to make the resulting fly ash usable. The inventors have found that adding an amine sacrificial agent can make fly ash concrete including activated carbon useful without employing the expensive treatment methods associated with activated carbon.
To address the above problems, an amine sacrificial agent is used to neutralize or eliminate the effect of the harmful components of fly ash on the air entrainment agent. Typically, the sacrificial agent acts preferentially (i.e. when present at the same time as the air entrainment agent, or even after the contact of the air entrainment agent with the fly ash, the sacrificial agent interacts with the fly ash), does not itself entrain air in significant amounts, and does not harm the setting action or properties of the cementitious material in the amounts employed. The inventors have now found certain amines capable of “neutralizing” the detrimental fly ash components, while having little or no influence on the air entrainment process provided by conventional air entrainment agents and having no adverse effects on the properties of the concrete mix and hardened concrete product. These amine sacrificial agents, introduced into the mixture at an appropriate time, render fly ash concrete comparable to normal concrete with respect to air entrainment. The finding of economically viable chemical additives of this type, as well as practical processes for their introduction into concrete systems, constitutes a major advantage for fly ash concrete technologies.
It has been found that primary, secondary, and tertiary non-aromatic amines are the most suitable as sacrificial agents, namely compounds selected from the group consisting of the structure NR 1 R 2 R 3 , wherein R 1 is substituted or unsubstituted non-alkoxylated C 5-22 alkyl, substituted or unsubstituted non-alkoxylated C 5-22 alkenyl, substituted or unsubstituted non-alkoxylated C 5-22 alkynyl, substituted or unsubstituted C 2-22 alkoxylated alkyl, substituted or unsubstituted C 2-22 alkoxylated alkenyl, or substituted or unsubstituted C 2-22 alkoxylated alkynyl, R 2 and R 3 are each independently selected from hydrogen, substituted or unsubstituted C 1-22 alkyl, substituted or unsubstituted C 2-22 alkenyl, or substituted or unsubstituted C 2-22 alkynyl. In some embodiments, the Log K ow is in the range of −3 to +2 (e.g., −2 to +2) and/or the HLB value is in the range of 5 to 20 (e.g., 4 to 18). The alkyl, alkenyl or alkynyl chains can be branched or straight chains. R 2 and R 3 can be optionally alkoxylated. The R 1 , R 2 and R 3 can be substituted with groups such as halogen, carbonyl, hydroxyl, amine, and the like. In some embodiments, these compounds are used in pure or substantially pore form.
In some embodiments, one or more of R 1 , R 2 , and R 3 is independently an alkoxylated or non-alkoxylated, substituted or unsubstituted fatty acid residue. In some embodiments, R 1 , R 2 , and R 3 can be selected from the group consisting of saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, and mixtures thereof.
In some embodiments, R 1 is a higher alkyl, alkenyl or alkynyl group having 7 or more carbon atoms (e.g, C8-C25 or C10-C20) and is generally an alkyl or alkenyl group. The R 2 and R 3 groups can also be a higher alkyl, alkenyl or alkynyl group although, in some embodiments, are lower alkyl, alkenyl or alkenyl groups (e.g. C1-C5) such as C1-C3 alkyl or hydrogen. Exemplary compounds include tridodecylamine, dodecyldimethylamine, octadecyldimethylamine, cocoalkyldimethylamines, hydrogenated tallowalkyldimethylamines, oleyldimethylamine, dicocoalkylmethylamine, and mixtures thereof. The compounds can also be polyetheramines including the groups for R 1 , R 2 and R 3 described above and further being alkoxylated to the levels described herein.
In some embodiments, one or more of R 1 , R 2 , and R 3 is independently amino-substituted (e.g. with a NR 4 R 5 group where R 4 and R 5 are H or substituted or unsubstituted, alkoxylated or non-alkoxylated, alkyl, alkenyl or alkynyl groups). For example, the amine sacrificial agent can be a diamine compound wherein R 1 is amino-substituted. Exemplary diamines include polyetherdiamines (such as polyoxypropylenediamines and polyoxyethylene diamines) wherein the average level of alkoxylation is from 1 to 10, from 1.5 to 9 or from 2 to 8. Suitable alkoxylated diamines can have the formula NH 2 —R—(R 1 O) x —NH 2 wherein R is C1-C5 alkyl, R 1 is C2-C4 alkyl, and x is the level of alkoxylation. For example, polyoxypropylenediamines are commercially available as Jeffamine D 400 and Jeffamine D 230; and triethyleneglycol diamine is commercially available as Jeffamine EDR 148, all from Huntsman International LLC. In some embodiments, the diamines are non-alkoxylated wherein x is 0 and R can be C5 or greater (e.g. C8-C25 or C10-C20). In some embodiments, the diamines are alkoxylated and have the formula R 3 ((R 4 O) w H)N—R 2 —N((R 5 O) y H)((R 6 O) z H) wherein R 2 is C1-C5 alkyl, R 3 is C1-C25 alkyl, alkenyl or alkynyl, R 4 , R 5 and R 6 are independently C2-C4 alkyl, one or more of x, y and z is greater than 0, and the total level of alkoxylation (w+y+z) is 1 to 10, 1.5 to 9 or 2 to 8. In some embodiments, R 3 is C5-C25 alkyl, alkenyl, or alkynyl (e.g. C8-C25 or C10-C20 alkyl). Exemplary alkoxylated diamines include N-oleyl-1,1′-iminobis-2-propanol and N-tallowalkyl-1,1′-iminobis-2-propanol. One commercially available example is N-tallowalkyl-1,1′-iminobis-2-propanol available from Akzo Nobel as Ethoduomeen T/13N. In some embodiments, the diamines can be non-alkoxylated (w+y+z)=0 and R 2 can be C5 or greater (e.g. C8-C25 or C10-C20).
In some embodiments, the amine is hydroxyl substituted (e.g. at one, two or three of R 1 , R 2 and R 3 ) and is an alcoholamine. In some embodiments, R 1 is higher alkyl as described above and can be optionally substituted with a carbonyl group and one or more of R 2 and R 3 are hydroxyl substituted. For example, Amadol 1017 commercially available from Akzo Nobel and having the formula CH 3 (CH 2 ) 10 C(═O)N(CH 2 CH 2 OH) 2 can be used. Alternatively, R 1 and one or more of R 2 and R 3 can be hydroxyl substituted.
In some embodiments, the amine sacrificial agent has a particular “Hydrophilic Lipophilic Balance” (HLB) rating, or oil/water (or octanol/water) partition coefficients (K OW ). These terms are understood in the art and are described, for example, in U.S. Pat. No. 7,485,184, which is hereby incorporated by reference in its entirety. In some embodiments, the HLB value of the sacrificial agent or the mixture of sacrificial agents is in the range of 5 to 20 (e.g., 4 to 18). In some embodiments, the Log Kow for the sacrificial agent can be in the range of −3 to +2 (e.g. −1 to +2).
Combinations of these amine sacrificial agents can be used as the sacrificial agent composition. For example, in some embodiments, dodecyldimethylamine, polyoxypropylenediamine, triethyleneglycol diamine, and mixtures thereof are used as the sacrificial agent. In some embodiments, the sacrificial agent can two or more amine sacrificial agents in weight a ratio of 1:1-1:50 wherein the total sacrificial agent is as described herein. For example, the sacrificial agent can include a first component having a compound A from the group of tridodecylamine, dodecyldimethylamine, octadecyldimethylamine, cocoalkyldimethylamines, hydrogenated tallowalkyldimethylamines, oleyldimethylamine, dicocoalkylmethylamine, and mixtures thereof (e.g. dodecyldimethylamine), and a second compound B from the group of polyetheramines, diamines, alcoholamines, all as described above, and mixtures thereof (e.g. polyoxypropylenediamine), wherein the weight ratio of compound A to compound B is 2:1 to 1:50, 1.25:1 to 1:25, or 1:1 to 1:5. In some eases, it can be advantageous to mix a sacrificial agent having different HLB values (e.g. high and low values) to produce a combined sacrificial agent mixture that is approximately neutral in its effect on the entrainment of air in the mixture. In this way, it is possible to use highly active sacrificial agents that would otherwise interfere too much with the entrainment of air.
In some embodiments, the amounts of such sacrificial agents are sufficient to neutralize the harmful components of the fly ash that adsorb or react with the air entrainment agents. The required minimum dosage can be determined experimentally through air entrainment protocols since, as discussed earlier and shown below, the deleterious effects of fly ash components are not necessarily directly related to their carbon content or LOI. In some embodiments, the sacrificial agents can be used in reasonable excess over the neutralizing amounts without entrainment of excess air (or reduction of such entrainment) or harming the concrete mixture or the subsequent setting action or properties of the hardened concrete. This means that an amount can be determined which exceeds the neutralizing amount required for a fly ash containing the highest amount of the harmful components likely to be encountered, and this amount can then be safely used with any fly ash cement mixture.
The amine sacrificial agents can be used in combination with one or more sacrificial agents described in U.S. Pat. No. 7,435,184, which is incorporated by reference herein in its entirety. For example, additional sacrificial agents can include sodium naphthoate, sodium naphthalene sulfonate, sodium diisopropyl naphthalene sulfonate, sodium cumene sulfonate, sodium dibutyl naphthalene sulfonate, ethylene glycol phenyl ether, ethylene glycol methyl ether, butoxyethanol, diethylene glycol butyl ether, dipropylene glycol methyl ether, polyethylene glycol and phenyl propylene glycol and combinations thereof. In addition, In some embodiments, sodium diisopropyl naphthalene sulfonate is included with the amine sacrificial agent in the sacrificial agent composition. The additional sacrificial agent can be included at a weight ratio of non-amine sacrificial agent to amine sacrificial agent of 1:2 to 1:150, or 1:5 to 1:100, or 1:10 to 1:75.
In some embodiments, the amine sacrificial agents can be used in combination with a water reducer. For example, lignosulfonates and polynaphthalene sulfonates have been found to particularly enhance the properties of the amine sacrificial agents. The water reducer can be included in a weight ratio of water reducer to amine sacrificial agent of 40:1 to 1:1.25 or 15:1 to 2:1.
The sacrificial agents can be added at any time during the preparation of the concrete mix. In some embodiments, they are added before or at the same time as the air entrainment agents so that they can interact with the fly ash before the air entrainment agents have an opportunity to do so. The mixing in this way can be carried out at ambient temperature, or at elevated or reduced temperatures if such temperatures are otherwise required for particular concrete mixes. The sacrificial agents can also be premixed with the fly ash or with the air entrainment agent.
It is particularly convenient to premix the sacrificial agent with the fly ash because the sacrificial agent can commence the interaction with the harmful components of the fly ash even before the cementitious mixture is formed. The sacrificial agent can simply be sprayed or otherwise added in liquid form onto a conventional fly ash and left to be absorbed by the fly ash and thus to dry. If necessary, the sacrificial agent can be dissolved in a volatile solvent to facilitate the spraying procedure. Fly ash treated in this way can be prepared and sold as an ingredient for forming fly ash cement and fly ash concrete.
Surprisingly, it has also been found that the sacrificial agent is even effective when added after the mixing of the other components of the cementitious mixture (including the air entrainment agent). Although not wishing to be bound by a particular theory, it appears that the sacrificial agent can reverse any preliminary deactivation of the air entrainment agent caused by contact with the fly ash, and thus reactivate the air entrainment agent for further air entrainment. It is observed, however, that the beneficial effect of the sacrificial agents is somewhat lower when added at this stage rather than when added before or during the mixing of the other components.
As noted above, in some embodiments, the chemical additives used as sacrificial agents are not effective air entrainment agents in the amounts employed, so that they do not contribute directly to air entrainment and can thus also be used in normal concrete containing no fly ash. This confers on the sacrificial agents the particularly important feature that these sacrificial agents can be introduced at dosages higher than the minimum dosage required to restore normal air entrainment without leading to erratic air entrainment and excessive air entrained levels. If one of the sacrificial agents used in a combination of sacrificial agents exhibits some surfactant (air entrainment) properties, it can be proportioned in such a way that the combination of sacrificial agents will entrain less than 2% air (or less than 1% air, or substantially no air), above the control values, in normal concrete without any fly ash. That is to say, when a concrete formulation is produced without fly ash, but with an air entrainment agent, the extra amount of air entrained when a sacrificial agent is added represents the extra air entrained by the sacrificial agent. The amount of air entrained in a cementitious mixture can be measured by determination of specific gravity of the mixture, or other methods prescribed in ASTM procedures (ASTM C231, C173, and C138—the most recent disclosures of which are incorporated herein by reference in their entirety).
Typical concrete air entrainment agents are n-dodecylbenzene sulfonate salts (referred to as Air 30) and tall oil fatty acid salts (referred to as Air 40). The typical dosage range of these ingredients in portland cement concrete mixes is 0.002 to 0.008 wt % of the cementitious components. The targeted air entrainment for the cementitious composition is typically 6-8 vol % air.
Other components of the cementitious mixtures are water, cement and fly ash. These can be used in proportions that depend on the type of material desired (e.g., pastes, grouts, mortars, concrete) and on the required fresh and hardened properties of the finished material. Such systems and their composition, as well as equipment and protocols for their preparation, are well known in the art; for mortars and concrete, these are adequately described in standard reference texts, such as ASTM Cement and Concrete (e.g., 4.01, 4.02); Design, and Control of Concrete Mixtures—Portland Cement Association; and American Concrete Institute—Manual of Concrete Practice (the disclosures of which are incorporated herein by reference). For pastes, the composition and preparation equipment and protocols will be described in detail in following sections. In practice, the content of various ingredients in a cementitious mixture are often reported as weight ratios with respect to the cement or to the total cementitious materials when other cementitious materials such as fly ash, slag, etc., are present. These ratios are well known to persons skilled in the art.
Once formed, the cementitious mixture can be used in any conventional way, e.g. poured into a form and allowed to harden and set. The hardened product will contain fly ash and entrained air, but no excess of air entrainment agent that could adversely affect the air content and properties of the hardened product.
The cementitious mixtures can include other standard or specialized concrete ingredients known to persons skilled in the art.
The following examples are provided to more fully illustrate some of the embodiments of the present invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventors to function well in the practice of the invention, and thus can be considered to constitute exemplary modes for its practice. However, those of skill is the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments that are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention. Parts and percentages are provided on a per weight basis except as otherwise indicated.
EXAMPLES
Example 1
PACT Formulation
A sacrificial agent formulation (PACT) is prepared by mixing polyoxypropylenediamine, dodecyldimethylamine, and optionally sodium diisopropylnapthalenesulfonate. For the following examples, PACT was formulated as follows: 0.05% dodecyldimethylamine and 0.15% polyoxypropylenediamine, by weight of fly ash.
Composition Preparation
To prepare the composition, the aggregate is mixed with partial water followed by the portland cement. Fly ash combined with activated carbon is then added followed by the PACT formulation and the air entrainment agent. Alternatively, the PACT foundation can be added directly to the fly ash. Additional water is added to obtain a 4-6 inch slump. The composition is then mixed using a rotary mixer, and tested for volume percentage of air using a pressure meter according to the ASTM C 231 method.
Activated carbon for the following examples was obtained from three sources:
PAC-A: Norit HgLH (Norit Americas Inc., Marshall, Tex.) PAC-B: ADA-ES (ADA Environmental Solutions, Littleton, Co.) PAC-C: Calgon MC Plus (Calgon Carbon, Pittsburgh, Pa.).
The air entrainment agent used in the following examples was MB-AE 90 (BASF Construction Chemicals, Shakopee, Minn.) and is labeled as AEA-1.
Example 2
The competitive absorption by PAC-C with various sacrificial agents at saturated concentrations was determined ( FIG. 1 ). The Once labeled Model AEA (DDBS) displays the absorption of an air entrainment agent (dodecylbenzenesulfonate (DDBS)) by MC activated carbon without the presence of a sacrificial agent. The trace labeled DDBS (with SA-A2) displays the absorption of DDBS by PAC-C and Jeffamine EDR-148. The trace labeled DDBS (with SA-C) displays the absorption of DDBS by MC activated carbon and Jeffamine 230. The trace labeled DDBS (with SA-J4) displays the absorption of DDBS by MC activated carbon and Jeffamine 400.
Example 3
The percentage of air in concrete with increasing concentrations of air entraining agent AEA-1 with varying amounts of activated carbon samples PAC-A, PAC-B, and PAC-C was determined. The amounts tested for each activated carbon sample include 0.75% and 1.5% ( FIG. 2 ). Cement and fly ash cement independently served as controls. All activated carbon samples increased the air entraining agent demand.
Example 4
The dosage of an air entrainment agent for 6% air in concrete with increasing amounts of carbon content with activated carbon samples PAC-A, PAC-B, and PAC-C was determined ( FIG. 3 ). Fly ash served as the control.
Example 5
The percentage of air in concrete with increasing concentrations of an air entrainment agent (AEA-1) with varying amounts of activated carbon (PAC-A) was determined ( FIG. 4 ). Fly ash served as the control. The presence of activated carbon caused the air entraining admixture demand to reach unacceptable levels.
Example 6
The percentage of air in concrete with increasing concentrations of an air entrainment agent (AEA-1) with varying amounts of activated carbon (PAC-A) with and without PACT (as formed in Example 1) was determined ( FIG. 5 ). The amounts tested include 0.75% PAC, 2% PAC, 3% PAC, 0.75% PAC with PACT, 2% PAC with PACT, and 3% PAC with PACT. Fly ash served as the control. The inclusion of PACT in the activated carbon formulations reduced the air entraining admixture demand to acceptable levels.
Example 7
The percentage of air in concrete with increasing concentrations of an air entrainment agent (AEA-1) with fly ash treated with activated carbon (PAC-A) in the presence of PACT was determined ( FIG. 6 ). The amounts tested included fly ash treated with 1.5% activated carbon and fly ash treated with 3% activated carbon. The PACT was present in constant, high dosage. Untreated fly ash served as the control. Increasing the dosage of PACT resulted in a performance comparable to that of untreated fly ash.
Example 8
The percentage of air in concrete with increasing concentrations of an air entrainment agent (AEA-4) with PACT treated fly ash in the presence and absence of 3% activated carbon (PAC-A) was determined ( FIG. 7 ). Both the PACT treated fly ash that contained activated carbon and the PACT treated fly ash that did not contain activated carbon displayed similar entraining properties.
Example 9
The percentage of air in concrete with varying amounts of activated carbon (PAC-A) with a constant concentration (1 oz/cwt) of an air entrainment agent (AEA-1) was determined ( FIG. 8 ). The air entrainment agent was treated with PACT. Untreated AEA-1 served as the control. PACT treatment was shown to minimize air fluctuations over a broad range of PAC contamination levels.
Example 10
The percentage of air in concrete with increasing concentrations of air entrainment agent (AEA-1) was determined for untreated activated carbon and activated carbon treated with PACT ( FIG. 9 ). The activated carbon samples were obtained from three different sources (PAC-A, PAC-B, and PAC-C). PACT was effective for all of the PAC samples tested; however, in some cases, it may be better to adjust the formulation depending upon the PAC source.
Example 11
The percentage of air in concrete with increasing concentrations of air entrainment agent (AEA-1) was determined for high quality fly ash having a LOI of about 1% and a low quality fly ash having a LOI of about 2.5% with or without the addition of CF PAC-C activated carbon, a concrete friendly activated carbon available from Calgon Corp. and present in an amount of 3% ( FIG. 10 ). The concrete friendly activated carbon influenced air entrainment, but did not compensate for underlying ash quality issues related to high or varying native carbon content.
Example 12
The percentage of air in concrete with increasing concentrations of air entrainment agent (AEA-1) was determined for the same high quality and low quality fly ashes from Example 11 with or without the addition of CF PAC-C activated carbon and/or PACT ( FIG. 11 ). PACT effectively decreased the negative influence of carbon. | A method of producing cementitious mixtures containing fly ash as one of the cementitious components, under air entrainment conditions is described. The method involves forming a mixture comprising water, cement, fly ash, optionally other cementitious materials, aggregate, conventional chemical admixtures, and an air entrainment agent and agitating the mixture to entrain air therein. Additionally, at least one amine sacrificial agent is included in the mixture. The cementitious mixtures and hardened concretes resulting from the method and fly ash treated with sacrificial agent, or air entrainment agent/sacrificial agent combinations, are also described. |
TECHNICAL FIELD OF THE INVENTION
The present invention is directed in general to variable-speed vehicle drive systems and, in particular, to such systems which employ an "on-off" power source and a power storage device to regulate power delivered from the source.
BACKGROUND OF THE INVENTION
Many well-defined mechanical devices are available for use in vehicle propulsion. Some, however, do not lend themselves to use in-present day drive train design, because vehicle speed is controlled by engine speed, vehicle speed being directly related to engine speed by the mechanical transmission which adjusts the gear ratio between the driving wheels and the engine to the best value for the torque/speed requirement. Decoupling vehicle speed (wheel RPM) from engine speed permits the use of constant speed engines or even variable speed engines where engine speed is determined by factors other than vehicle speed such as power demand.
Historically, it has been demonstrated that vehicles powered by "on-off" engines can achieve superb fuel mileage. Such engines comprise one or more cylinders which can separately operate in one of two selectable states: either at a predetermined "on" speed (typically corresponding to the most efficient operating speed of the engine and termed its "on" mode) or at an "off," or zero, speed (termed its "off" mode). Shell Oil Company has sponsored mileage contests for years. In 1977 (See Popular Science, December 1977, page 100) an entry by Cranfield Institute of Technology achieved 914 miles on one gallon of gasoline by careful management of the vehicle speed i.e. speeding up, coasting (engine off), speeding up, coasting, etc. throughout the race. Even though this demonstrates good energy management, this technique of driving would be totally unacceptable to the driving public.
Considerable energy is lost in heat dissipation every time a vehicle is brought to a stop. Regenerative braking has been in use for years in railway cars where the electric drive system permits the reclamation of some of the kinetic energy by pumping it back into the supply system. This method is impractical for single vehicles isolated from a large energy system; however, other well known short term storage devices such as the flywheel are available for use in energy storage. To take advantage of short term storage i.e. the flywheel, and prime power sources such as the "on-off" engine, a means of controlling vehicle speed other than by engine speed must be used. A transmission capable of coupling the energy from the power source to the drive wheels so that the torque and wheel speed requirement is met is needed. Many forms of variable speed transmissions are available that might fill this need but the well known Ward-Leonard system which uses a D.C. generator and a D.C. motor provides excellent speed control of the motor while the generator can be either a fixed speed or variable speed and not related to the motor speed.
A judicious combination of the best qualities of available technology can provide a system that is capable of greatly improved efficiency.
SUMMARY OF THE INVENTION
A broad objective of the present invention is to provide an efficient means to power a vehicle by minimizing fuel consumption and reclaiming energy normally lost. More particularly, the object of the present invention is to provide a drive system for a road vehicle that will deliver acceleration, deceleration, cruising and hill climbing performance typical of present day vehicles so that no performance is sacrificed while obtaining improved efficiency.
The present invention provides a variable speed piston engine as the prime source, its output power being based on demand; a high inertia acyclic D.C. generator where the rotor inertia serves as a flywheel to provide a steadying influence on the engine and to store reclaimed braking energy; a suitably sized D.C. motor to convert the available electrical power from the generator into torque to move the vehicle drive wheels; and a Ward-Leonard control system where the generator and motor in combination provide a bidirectional, variable speed transmission capable of complete speed control of the vehicle.
It is accordingly a primary object of the present invention to provide a variable speed vehicle drive system comprising: (i) a generator having a relatively high inertia rotor, the generator coupled to an on-off source of mechanical energy, the generator converting the mechanical energy into electrical energy, the rotor storing the mechanical energy when the on-off source is on and releasing the mechanical energy when the on-off source is off, (ii) a motor coupled to a drive member on the vehicle, the motor receiving the electrical energy from the generator and (iii) means for storing mechanical energy recovered from the drive member during braking of the vehicle in the rotor.
Another object of the present invention is to provide a variable speed vehicle drive system wherein the on-off power source is a piston engine.
A further object of the present invention is to provide a variable speed vehicle drive system wherein the generator is a D.C. acyclic generator.
Yet another object of the present invention is to provide a variable speed vehicle drive system wherein the rotor acts as a flywheel.
Still a further object of the present invention is to provide a variable speed vehicle drive system wherein the motor is a high torque motor.
Yet a further object of the present invention is to provide a variable speed vehicle drive system wherein the generator and the motor cooperate to form a Ward-Leonard system.
Still another object of the present invention is to provide a variable speed vehicle drive system wherein the motor is coupled to the drive member through a reducing gear.
Another object of the present invention is to provide a variable speed vehicle drive system wherein the drive member is a wheel.
Yet another object of the present invention is to provide a variable speed vehicle drive system wherein the storing means is a regenerative braking system.
Still a further object of the present invention is to provide a variable speed vehicle drive system wherein a rated full-load speed of the on-off source is between 30 and 50 percent of a no-load speed of the on-off source.
Yet a further object of the present invention is to provide a variable speed vehicle drive system wherein an upper limit speed of the on-off source is between 150 and 160 percent of a no-load speed of the on-off source.
Still another object of the present invention is to provide a variable speed vehicle drive system wherein the rotor can store sufficient energy to accelerate the vehicle from rest to 60 miles per hour.
And another object of the present invention is to provide a variable speed vehicle drive system wherein the on-off source supplies mechanical energy to the generator only when a rotational speed of the rotor drops below a predetermined minimum speed.
The foregoing has outlined rather broadly the features and technical advantages of the present invention that the detailed description of the present invention that follows may be better understood. Additional features and advantages of the present invention will be described hereinafter which form the subject of the claims of the present invention. Those skilled in the art should appreciate that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a representational block diagram of the general concept of the present invention;
FIG. 2 illustrates the energy available from a particular cylindrical flywheel with different diameters;
FIG. 3 illustrates the kinetic energy possessed by a moving vehicle of three different weights across a speed spectrum of 80 MPH;
FIG. 4a illustrates the "on-off" characteristic of the cylinders firing of the prime power source as the speed varies;
FIG. 4b illustrates engine output torque as engine speed varies;
FIG. 4c illustrates engine and flywheel energy as engine speed varies;
FIG. 5 is a schematic illustration of one embodiment of the present invention illustrating aspects of FIG. 1 in more detail;
FIG. 6 is a block diagram of one cylinder of the on-off engine and controls; and
FIG. 7 illustrates the valve control system for the prime power source.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention may generally be understood from FIG. 1 as comprising a vehicle 11 powered by a variable speed "on-off" piston engine 12 connected to a high inertia acyclic D.C. generator 13 that is used to extract mechanical power from the engine 12. The high inertia of a rotor (not shown) within the generator 13 serves as an energy storage flywheel. The rotor's weight, configuration and rotational speed are determined by the required electrical output power for driving the vehicle 11 and the intermittent storage capacity needed to absorb the energy normally lost in braking. The engine 12 and the rotor/flywheel within the generator 13 cooperate to provide mechanical power to enable the generator 13 to produce electrical power. The rotational energy available from the engine-flywheel source is thereby converted into electrical energy and transmitted to a D.C. motor 14, which receives electrical power from the generator 13 and produces mechanical power therefrom, transmitting that mechanical power to driving wheels 16 by a conventional drive means 15, which may comprise a mechanical, hydraulic, pneumatic or hybrid transmission. The generator 13 and motor 14 cooperate to provide a Ward-Leonard system, which is well known and understood in the prior art as having excellent speed control characteristics, the system being able to accurately control motor 14 speed over a range of zero to several thousand RPM. This speed control system is required for operating the vehicle drive means 15 since, at certain times, the engine-flywheel power source will be decreasing in rotational speed as the drive wheels 16 are increasing in rotational speed in distinction to conventional propulsion systems where the engine speed increases as the speed of the vehicle increases.
The energy E stored in a flywheel when accelerating, and delivered when the flywheel decelerating, is given by the equation:
E=0.5m(V.sub.1.sup.2 -V.sub.2.sup.2)
where V 1 is the initial and V 2 is the final speed of the rim and m is the mass of the rim. The maximum rim speed of a flywheel is governed by the tensile strength of the material as well as the design of the flywheel. For steel, the limitation is approximately 27,000 feet per minute.
Turning now to FIG. 2, shown are a plurality of kinetic energy curves representing the capability of a cylindrical steel flywheel 10 inches in length and with diameters varying from 20 inches down to 12.89 inches. Each curve stops at the limiting rim speed.
Turning now to FIG. 3, illustrated is the kinetic energy possessed by a moving vehicle that weighs between 2000 and 4000 pounds and at velocities ranging from 0 to 80 MPH. Note that at 60 MPH, a 3000 pound vehicle possesses approximately 360,000 foot pounds of energy and that 360,000 foot pounds of energy is available from a 17.5 inch diameter flywheel initially turning at 3800 RPM and slowing to 1500 RPM.
In the present invention, the propulsion characteristics of the "on-off" engine 12 are matched to the characteristics of the high inertia rotor of the acyclic generator 13 since the rotor also serves as the flywheel. When the generator 13 is operating at approximately 3800 RPM, the speed at which 360,000 foot pounds of energy is stored, the engine 12 is "off" (free wheeling). As the generator rotor slows, the engine begins to fire depending on the speed as illustrated in FIG. 4.
Most "on-off" engines i.e. stationary engines, have been conventionally designed as one cylinder engines with fuel intake controlled by a governor. The present invention, in its preferred embodiment, uses an "on-off" engine 12 having multiple cylinders (preferably 4 or more) to achieve greater power and smoother operation.
Turning now to FIG. 4, illustrated is a power demand approach employed in the preferred embodiment of the present invention in controlling the "on-off" engine 12. On starting the engine, all cylinders fire to accelerate the engine. As engine RPM increases, cylinders will cease firing one by one until the engine reaches a desired idle speed. At this speed (approximately 3800 RPM in the preferred embodiment) all cylinders will have ceased firing. As the speed slows, one cylinder will fire occasionally to overcome internal losses while engine speed is maintained steady by the flywheel nature of the rotor.
As the vehicle begins to move and power is required, the engine-flywheel-generator begins to slow as the flywheel gives up energy. If power demand persists, the engine will continue to slow and, one by one, the cylinders will start firing until all are firing. Driving demands vary widely depending on whether acceleration or braking is required. Once the vehicle speed has been established on level terrain, the power required to overcome windage and road friction becomes a fraction of that required to accelerate and the number of firing cylinders decreases until equilibrium is reached.
Turning now to, FIG. 5 shown in more detail is the drive system of the present invention. The engine 12/generator 13 combination is preferably installed with its rotational axis 51 vertical in the vehicle engine compartment (not shown) so as to minimize gyroscopic moments when the vehicle is turning. To accommodate this configuration, the engine 12 is preferably of a radial design so as to minimize length and the generator 13 is preferably of an acyclic design so as to minimize weight and provide a solid rotor 52 to provide the flywheel feature. This type of generator 13 has been marketed for years by electrical manufacturers and is ideally suited to this application. The acyclic generator 13 produces pure direct current at a relatively low voltage but with high current capacity so that the required power can be delivered to the load via bus bars 54, 55. The D.C. motor 14 can be of any configuration suitably sized to deliver the required power for vehicle acceleration which should correspond to the largest demand the vehicle can be expected to make of its drive system.
The vehicle drive means 15 is of conventional design and may comprise, for example, a conventional differential and rear axle assembly. However, two motors 14, with appropriate gear reduction, can be used to drive the vehicle wheels 16 thus eliminating the need for a differential. The generator 13 and motor 14 cooperate to form a Ward-Leonard system, which, in the preferred embodiment of the present invention, is placed under control of a Ward-Leonard control 53. The control 53 is a straightforward, conventional electrical design that provides field control of both the generator and the motor so that the desired speed/torque characteristic for acceleration is generated and the desired speed/torque characteristic for braking is generated.
In the preferred embodiment of the present invention, energy normally lost during braking of the vehicle is recovered and stored in the rotor 52 in the form of additional rotational kinetic energy. Recovery and storage (termed "regeneration") can occur by one of several means. As illustrated in FIG. 5, motor 14 can convert mechanical energy present in the inertia of the vehicle into electrical energy by operating the motor 14 as a generator. The generator 13 can likewise be operated as a motor to convert the electrical energy delivered to the generator 13 via the bus bars 54, 55 into mechanical energy, to be stored in the rotor 52. Alternatively, mechanical, hydraulic or pneumatic systems of conventional design can be employed to couple the drive wheels 16 to the rotor 52 to recover energy therefrom during braking.
To accelerate a 3000 pound vehicle at 8.8 feet per second requires 820 pounds of force applied to the vehicle. Application for 10 seconds to achieve 88 feet per second requires 131 horsepower. To climb a 10 degree slope requires 83 horsepower. To cruise at 60 MPH, requires a force of approximately 100 to 150 pounds to overcome aerodynamic drag and road friction. This equates to a horsepower requirement of 24. The engine is sized to handle the hill climbing requirement with all cylinders firing. Thus each cylinder must deliver 20 to 25 horsepower when firing and must provide minimum holdback when not firing.
Turning now to FIG. 6, illustrated in block diagram form is an "on-off" engine for a drive train constructed in accordance with the present invention. For purposes of FIG. 6 the "on-off" engine has only one cylinder. The piston engine consists of four cylinders 60 that provide torque to an output shaft 63 through a crankshaft 62 using four pistons 61. The intake valves 64 and exhaust valves 65 are controlled by engine computer 66. Fuel is fed to the engine by a fuel pump 67 supplying fuel to a computer controlled injection system 68. The ignition system 69 supplies high voltage to the spark plugs 70. In the "on" mode, the computer opens valves, closes valves, injects fuel and supplies spark plug voltage as in any four stroke engine with the throttle open. In the "off" mode, the computer inhibits fuel injection and ignition and re-times the valves to pump air without compression so as to minimize the engine drag on the output shaft.
When the maximum rim speed of the generator rotor is approached when in the braking mode and storing energy by increasing the speed of the rotor, the computer will re-time the valves to cause compression so that the engine can begin holding back to limit rotational speed.
FIG. 7 illustrates in block diagram form the computational elements required to provide valve control. The generator and drive motor provide the means for speed control and decoupling of vehicle speed from engine speed. As previously described, the method used is the Ward-Leonard method which has been used for many years to provide excellent speed control. The generator field is controlled to provide a variable voltage to the drive motor. This voltage can easily be reversed when it is required to move the vehicle in the opposite direction. By proper control of the drive motor field, the desired torque/speed can be provided to the drive wheels. Regenerative braking is provided by reducing the generator voltage while maintaining the drive motor field. Thus the drive motor acts as a generator and the generator is driven as a motor which causes the rotor to increase in speed thereby storing the braking energy.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Specifically, the engine does not need to be a piston engine, but can, instead, be a rotary engine or thermal cycle engine. The generator can be of any design, and the rotor need not act as the flywheel. Thus the flywheel can be separate from the generator. The motor can be of any conventional design and can be used alone or in combination with other motors. | A vehicle drive system which consists of a piston engine prime power source combined with a high inertia acyclic generator used in conjunction with a D.C. Motor to provide a bi-directional variable speed transmission of power between the load and the energy source. Sufficient energy accumulates in the inertia of the generator rotor to provide intermittent quantities of energy for acceleration of the vehicle. In this manner, highly efficient engines not presently suitable for use in vehicle propulsion can be utilized as well as the recouping of kinetic energy (regenerative braking) usually lost in heat dissipation by the friction brakes. |
This is a continuation-in-part of Ser. No. 890,928 filed July 31, 1986, now U.S. Pat. No. 4,730,154.
BACKGROUND OF THE INVENTION
This invention relates to an energy storage system and more particularly, but not by way of limitation, to a variable inertia energy storage system for storing large amounts of mechanical energy for an extended period of time on land or on a mobile vehicle.
Heretofore there have been a large number of different methods used and systems proposed for storing electrical power. These systems include the classical methods associated with nuclear power generating stations along with fuel cells, solar cells, inductors, capacitors and batteries.
Also there have been various types of methods used to store power including the use of high speed flywheels. Flywheels have long been used for storing mechanical power. These devices are designed to withstand forces associated with rotational rates of several thousand of revolutions per minute. The forces associated with these high speeds are destructive in nature and relatively minor structural defects can cause catastrophic failures.
In U.S. Pat. Nos. 4,509,006 and 4,546,264 the subject inventor discloses alternate energy storage systems for storing both mechanical and electrical energy in different types of land and space environments. The subject invention is a substantial improvement over, and an extension of, the state of the art energy storage systems.
SUMMARY OF THE INVENTION
The subject variable inertia energy storage system provides a means to store mechanical energy at reduced rpms. Further, the system is adaptable for land use or on mobile vehicles such as a truck, a train, a boat and other types of mobile equipment.
The storage system includes an enclosed circular housing disposed on a mounted base. A vacuum system may be applied to the enclosed housing for reducing pressure on the equipment therein. A rotatable central hub is mounted inside the housing and includes a plurality of equally spaced spokes extending outwardly therefrom. A mass is mounted on each of the spokes. A reversible drive motor for controllably moving the mass a desired distance from the axis of rotation of the hub is provided. Rotor-mounted motor/generator elements such as magnet coils or field coils cooperate with complementary motor/generator elements which can be positioned on the adjacent housing periphery. Relative motion between the motor/generator elements and the complementary elements provides for generating electricity or providing motive force at the command of an electrical controller. The controller includes an individual power controller, speed controller and vacuum pump controller for regulating the enclosed storage system.
The advantages and objects of the invention will become evident from the following detailed description of the drawings when read in connection with the accompanying drawings which illustrate preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B illustrate a top and side view of a storage system made in accordance with the present inventions.
FIGS. 2A and 2B illustrate two alternate motor/generator combinations used with the storage system.
FIG. 3 illustrates the use of a central hub in the housing for mounting a motor/generator.
FIG. 4 illustrates an enlarged side view of an outwardly extending spoke formed as a lead screw with a movable mass and a position scale.
FIG. 5 illustrates an alternate drive system for positioning the movable mass.
FIG. 6 illustrates the details of the power user and controller subsystem.
FIGS. 7A and 7B illustrate the use of wheel covers on the rotating spokes for reducing drag.
FIG. 8 illustrates a baseline concept of the movable masses.
FIGS. 9A, 9B and 9C illustrate an extendable or "ballerina" movable mass concept.
FIGS. 10A, 10B, 10C and 10D illustrate perspective views and a top view of an "umbrella" mass motion concept.
FIGS. 11A and 11B illustrate an "iris" apparatus for inertia control.
And, FIG. 12 illustrates an embodiment wherein the positioning drive motors serve as the inertial masses.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIGS. 1A and 1B the variable inertia energy storage system is designated by general reference numeral 10. The system 10 includes an enclosed housing 12 having a central hub 14 centered therein The hub 14 includes a plurality of spokes 16 each extending outwardly therefrom and each having a movable mass 18 mounted thereon. The central hub 14 includes reversible drive motors 20 for moving the masses 18 along the length of the spokes 16.
With continued reference to FIGS. 1A and 1B, disposed around the outer ends of the spokes 18 is a structural ring or hoop 22 having a plurality of rotor-mounted motor/generator elements 24, such as permanent magnets, magnet coils or field coils, mounted therearound. Also disposed in a spaced relationship around an outer periphery 26 of the housing 12 are complementary motor/generator elements 27. Thus, if the motor/generator elements positioned on rotating hoop 22 are magnets or magnet coils, the complementary motor/generator elements on stationary housing periphery 26 would be field coils, or vice versa.
Attached to the central hub 14 are slip rings 28 or an optical equivalent for control of the hub's drive mechanism. Also included are an optional slip ring power interface 30.
The storage system 10 is controlled by a central controller 32 shown in dotted lines and having a power controller 34, a speed controller 36 and a vacuum pump controller 38. The power controller 34 receives a user power requirement indicated by arrow 40 and controls power input 42 and electrical power output 44. The vacuum pump controller 38 is connected to vacuum pumps 46. The pumps 46 are used for drawing a vacuum or reducing pressure in the housing 12.
In operation, the power controller 34 positions the movable masses 18 proximate hub 14 for initiations in a motor configuration by energizing complementary electrical elements 27 which can be field coils on the housing 12. By sequencing the field polarity of coils 27 the speed of the elements 24, which can be permanent magnets, is increased, along with hoop 22, spokes 16, and attached movable masses 18. To reduce the electrical power initially required the movable masses 18 are moved inwardly using lead screws 48 shown in FIG. 4. The lead screws 48 are part of the spokes 16. When the masses 18 are moved inwardly the radial positions of the masses provide a minimum moment of inertia. As the speed of the masses 18 is increased the masses 18 are moved by the reversible drive motors 20 to the outside extremity adjacent the hoop 22 at a rate commanded through a motor drive controller 50 connected to the speed controller 36.
To reduce aerodynamic loss and pressure inside the housing 12 vacuum pumps 46 are used and commanded by the vacuum pump controller 38. As an alternative as shown in FIG. 1B, in combination with the vacuum system a low molecular weight gas, such as helium in helium bottles 52, can be introduced into the housing 12 through commands from the controller 32.
In FIG. 1B the system is shown with a plurality of counter rotating spokes 16 and masses 18 indicated by arrows 51 and 53. The hub 14 also includes support bearings 55.
In FIGS. 2A and 2B, two alternate motor/generator combinations used with the storage systems are shown. In FIG. 2A, direct shaft drive shaft 58 connects flywheel hub 14 to motor/generator armature 60 which rotates in disposed relation with motor/generator field windings 62. In FIG. 2B, shaft 58 connects with transmission 64 which further connects with a remote motor/generator system 66 such as through shaft 58A.
FIG. 3 illustrates the use of a two-part central hub 14A, 14B in the housing for mounting a motor/generator. Positioned within hub part 14A are field windings 68 and armature windings 70. In FIG. 3, one movable hub part 14A controls rotation of field windings 68 and the second hub part 14B, which can rotate in the opposite direction from hub part 14A, controls the armature windings 70.
An alternate drive system for positioning the movable mass 18 is shown in FIG. 5. The alternate system includes opposing, spaced chain pulleys 86, 88, continuous chain 90 with weight attachments 92, and position feedback sensors 94.
Referring now to FIG. 6 the user 300 places power demands 40 upon the central controller 32. The controller 32 operates under several of three primary modes. As an electric power source, electrical power is supplied by the electrical energy generator component 96 of system 10 under control of generator controller 99 to a direct power conditioning and distribution system 98. Here the power is stepped up or down as desired to the required potential and distributed for use by the various subsystems.
The system may also operate in an energy storage system mode. In this mode, commands are sent to controller 99, the power conditioner and distribution system for the motor control 100, and the motor controller 50. The electrical power/generator component 96 is conditioned by controller 50 as a motor and the motor counterrotates the spokes 16 in system 10 using energy supplied from an outside generator 301 through the electrical energy controller 99.
A user mode can also be activated. This is accomplished by demands to the electrical generator controller 102 made by the central controller 32. The electrical motor/generator component 96 of system 10 is electrically switched to a generator mode and the rotating inertial units (weights 18 on spokes 16) drive the field coils and armature in opposite directions. The generated electrical energy is routed to the defined subsystems by the power distribution and conditioning system 103. The mass distribution control system 104 interfaces with motor drive controller 50 through central controller 32 to maintain a constant RPM.
FIGS. 7A and 7B illustrate the use of wheel covers on the rotating spokes for reducing drag when it is not desired to use a low friction atmosphere (e.g. vaccuum or low molecular weight gas). In FIG. 7A, wheel cover 106 has a flat cross-sectional profile with aerodynamically shaped movable weights 18a. In FIG. 7B, non-aerodynamically shaped weights 18 are enclosed, with the spokes, by an aerodynamically shaped cover 108.
The objective of the wheel cover 106 or 108 is to reduce aerodynamic drag as the spokes rotate about the central hub. The preferred embodiments shown in FIG. 7A uses flat aerodynamic wheel covers that fill the gaps between the spokes. The use of aerodynamically shaped movable masses 18a will further reduce drag. The alternate design of FIG. 7B provides an aerodynamically smooth cover with all of the movable element inside the cover 108. Variations to provide lateral structural strength to the wheels can be included in the alternate design, as would be apparent to one skilled in the art given this disclosure.
FIG. 8 illustrates the baseline concept of the movable masses 18 on radially fixed with respect to hub 14 but axially rotatable spokes 16. In comparison, FIGS. 9A, 9B and 9C illustrate an extendable or "ballerina" movable mass alternative concept where the weights 110 are in the form of thin-walled cylindrical sections activated by respective drive motors 110A which can swing tangentially outward to a controlled degree (FIG. 9B) from the closed (FIG. 9A, 9C) position. As is evident from FIGS. 9A-9C, the thin-walled cylindrical sections are elongated members each having a distributed mass, rather than a point mass. However, as one skilled in the art would appreciate, each cylindrical section has an effective center of mass. The changing center of mass radial location for the swinging weights 110 provide a controllable changing moment of inertia similar to sliding weights 18 in the FIG. 8 base-line concept.
FIGS. 10A, 10B and 10C illustrate perspective views, and FIG. 10D a top view, of an "umbrella" mass motion concept. In this variation, masses 118 are fixed with respect to spokes 16 and spokes 16 activated by respective drive motors 118a swing radially outward from hub 14 to a controlled degree, in order to provide the controllable changing movement of inertia to system 10. When closed, the spokes plus attached weights rest and nest against hub 14 in the manner of two opposed umbrella frames.
FIG. 11A illustrates a movable mass variation based on an "iris" action. In this design a near standard iris mechanism is used where the iris blades 114 activated by respective drive motors 114a constitute the movable mass. As in the case of the FIG. 9A-9C embodiment, each of the iris blades 114 in the FIG. 11A and 11B embodiment is an elongated member with a distributed mass, rather than a point mass. In the maximum movement of inertia configuration depicted in FIG. 11B the iris is wide open with the center of mass close to the fixed outer ring 112. As energy is extracted from the system the iris is closed progressively to a minimum moment of inertia structure, thereby moving the center of mass closer to the axis of rotation of hub 14.
In a significant variation on the above described system, and further in accordance with the present invention, the reversible drive motors themselves can serve as movable masses 18. As embodied herein, and as best seen in FIG. 12, a lead screw spoke 216 is attached to the central hub 214 through a bearing 21. A position slide 280 made up typically of a smooth rod 202 with a position indicator rod 282 or other position indicator is provided for control system feedback so that current knowledge of the motor is available at all times.
The follower 200 is provided to prevent the entire reversible drive motor 203 from rotating. A bearing 201 is provided on the follower to reduce friction, and position readout 282 is provided to cooperate with slide 280.
Lead screw spike 216 is threaded. Reversible drive motor 203 is designed with a hollow armature 206 which is threaded on the inside 207 to match the lead screw spoke. The hollow armature is attached to the field 204 using standard means including bearings 205. Power and control information is provided to the motor 203 through cabling 208.
The lead screw 216 and rod 202 are attached to hoop 222 at the end of the fixed rod. Motor/generator elements 24, which in this case are shown as permanent magnets, are attached to hoop 222 such that a fixed distance is maintained relative to complementary motor/generator elements 27, field coils in this embodiment, which are attached to housing 12. RPM sensor 254 provides data to the controller/power supply (not shown in the FIG.).
Changes can be made in the construction and arrangement of the parts or elements of the embodiments as described herein without departing from the spirit or scope of the invention defined in the following claims. | A variable inertia energy storage system for storing large amounts of mechanical energy for an extended period of time on land or on a mobile vehicle includes a fly wheel having a rotating hub with spoke appendages each having an associated mass the center of which can be controllably changed with respect to the hub axis of rotation. The energy storage system also includes motor/generator elements for providing rotation forces to input mechanical energy to the flywheel or for generating electrical power for use on demand by a subsystem or the like. |
REFERENCE TO RELATED APPLICATION
The present application is a divisional application of U.S. application Ser. No. 11/205,934, filed on Aug. 17, 2005, now U.S. Patent No. 7,335,711, the disclosure of which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
This invention relates to olefin polymerization catalysts and their use in the polymerization of ethylenically unsaturated monomers.
BACKGROUND OF THE INVENTION
Olefin polymers such as polyethylene, polypropylene, which may be atactic or stereospecific, such as isotactic or syndiotactic, and ethylene-higher alpha olefin copolymers, such as ethylene-propylene copolymers can be produced under various polymerization conditions and employing various polymerization catalysts. Such polymerization catalysts include Ziegler-Natta catalysts and non-Ziegler-Natta catalysts, such as metallocenes and other transition metal catalysts which are typically employed in conjunction with one or more co-catalysts. The polymerization catalysts may be supported or unsupported.
The alpha olefin homopolymers or copolymers may be produced under various conditions in polymerization reactors which may be batch type reactors or continuous reactors. Continuous polymerization reactors typically take the form of loop-type reactors in which the monomer stream is continuously introduced and a polymer product is continuously withdrawn. For example, polymers such as polypropylene, polyethylene or ethylene-propylene copolymers involve the introduction of the monomer stream into the continuous loop-type reactor along with an appropriate catalyst system to produce the desired olefin homopolymer or copolymer. The resulting polymer is withdrawn from the loop-type reactor in the form of a “fluff” which is then processed to produce the polymer as a raw material in particulate form as pellets or granules. In the case of C 3+ alpha olefins, such a propylene or substituted ethylenically unsaturated monomers such as styrene or vinyl chloride, the resulting polymer product may be characterized in terms of stereoregularity, such as in the case of, for example, isotactic polypropylene or syndiotactic polypropylene.
The structure of isotactic polypropylene can be described as one having the methyl groups attached to the tertiary carbon atoms of successive monomeric units falling on the same side of a hypothetical plane through the main chain of the polymer, e.g., the methyl groups are all above or below the plane. Using the Fischer projection formula, the stereochemical sequence of isotactic polypropylene is described as follows:
In Formula 1, each vertical segment indicates a methyl group on the same side of the polymer backbone. Another way of describing the structure is through the use of NMR. Bovey's NMR nomenclature for an isotactic pentad as shown above is . . . mmmm . . . with each “m” representing a “meso” dyad, or successive pairs of methyl groups on the same said of the plane of the polymer chain. As is known in the art, any deviation or inversion in the structure of the chain lowers the degree of isotacticity and crystallinity of the polymer.
In contrast to the isotactic structure, syndiotactic propylene polymers are those in which the methyl groups attached to the tertiary carbon atoms of successive monomeric units in the chain lie on alternate sides of the plane of the polymer. Syndiotactic polypropylene using the Fisher projection formula can be indicated by racemic dyads with the syndiotactic pentad rrrr shown as follows:
Here, the vertical segments again indicate methyl groups in the case of syndiotactic polypropylene, or other terminal groups, e.g. chloride, in the case of syndiotactic polyvinyl chloride, or phenyl groups in the case of syndiotactic polystyrene.
Other unsaturated hydrocarbons which can be polymerized or copolymerized with relatively short chain alpha olefins, such as ethylene and propylene include dienes, such as 1,3-butadiene or 1,4-hexadiene or acetylenically unsaturated compounds, such as methylacetylene.
SUMMARY OF THE INVENTION
In accordance with the present invention, there are provided catalyst compositions and processes for the polymerization of ethylenically unsaturated monomers to produce polymers, including copolymers or homopolymers. Monomers, which are polymerized or copolymerized in accordance with the present invention, include ethylene, C 3+ alpha olefins and substituted vinyl compounds, such as styrene and vinyl chloride. A particularly preferred application of the invention is in the polymerization of propylene including the homopolymerization of propylene to produce polypropylene, preferably isotactic polypropylene and syndiotactic polypropylene having a high melting temperature, and the copolymerization of ethylene and a C 3+ alpha olefin to produce an ethylene alpha olefin copolymer, specifically an ethylene-propylene copolymer.
In carrying out the present invention, there is provided an olefin polymerization catalyst characterized by the formula:
B(FluL)MQ n (3)
In formula (3), Flu is a fluorenyl group substituted at at least the 2,7- and 3,6-positions by hydrocarbyl groups, preferably relatively bulky hydrocarbyl groups. L is a substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl group or a heteroorgano group, XR, in which X is a heteroatom from Group 15 or 16 of the Periodic Table of Elements, and R is an alkyl group, a cycloalkyl group or an aryl group. Preferably X is nitrogen, phosphorus, oxygen or sulfur. More preferably, X will take the form of nitrogen. R is an alkyl group or cycloalkyl group containing from 1 to 20 carbon atoms, or a mononuclear aromatic group which may be substituted or unsubstituted. Further, with respect to formula (3), B is a structural bridge extending between the groups L and Flu, which imparts stereorigidity to the ligand structure. Preferably, the bridge B is characterized by the formula ER 1 R 2 , in which E is a carbon, silicon or germanium atom, and R 1 and R 2 are each independently a hydrogen, a C 1 -C 10 alkyl group, an aromatic group or a cycloalkyl group. Further, with respect to formula (3), M is a Group 4 or Group 5 transition metal, preferably titanium, zirconium or hafnium. Q is selected from the group consisting of chlorine, bromine, iodine, an alkyl group, an amino group, an aromatic group and mixtures thereof, n is 1 or 2 and will have a value of 2 where the transition metal is zirconium, hafnium or titanium.
In one embodiment of the invention, the fluorenyl group Flu is substituted with an aryl group at each of the 2- and 7-positions and with a lower molecular weight substituent at each of the 3- and 6-positions. More specifically, the fluorenyl group is substituted at the 2- and 7-positions with a phenyl or substituted phenyl group and at each of the 3- and 6-positions with a bulky hydrocarbyl group containing at least 4 carbon atoms. Preferably, the bulky hydrocarbyl group at the 3- and 6-positions is a tertiary butyl group.
In the embodiment of the invention in which the metallocene component is substituted at the 2- and 7-positions with an aryl group as described above and at the 3- and 6-positions with a tertiary butyl group, the metallocene component is characterized by the formula:
wherein Ar is a phenyl group or substituted phenyl group.
In a specific embodiment of the invention in which the ligand component L is a heteroorgano group, the metallocene component is characterized by the formula:
wherein Ar is a phenyl group or a substituted phenyl group, and R is an alkyl group having from 1 to 20 carbon atoms or an aryl group having from 6 to 20 carbon atoms.
In a further embodiment of the invention in which the metallocene component incorporates a cyclopentadienyl group, the metallocene is characterized by the formula:
In formula (6), Ar is a phenyl group or substituted phenyl group, R′ is a C 1 -C 4 alkyl group or an aryl group, n is the number of substituents, from 0 to 4, E is a —C— group or an —Si— group, R 1 and R 2 are each independently a hydrogen, a C 1 -C 10 alkyl group, or a cycloalkyl group, or an aryl group, M is titanium, zirconium or hafnium, and Q is chlorine, a methyl group or a phenyl group. Preferably, in formula (6), the cyclopentadienyl group is unsubstituted, disubstituted or tetra-substituted to provide a metallocene component which exhibits bilateral symmetry. In another embodiment of the invention, however, the cyclopentadienyl group is monosubstituted or trisubstituted to provide a metallocene component which exhibits non-bilateral symmetry.
In yet a further embodiment of the invention, the metallocene component incorporates a cyclopentadienyl group which is substituted with a methyl group and a tertiary butyl group to provide a metallocene component characterized by the formula:
In formula (7), Ar is a phenyl group or substituted phenyl group, E is a —C— group or an —Si— group, R 1 and R 2 are each independently a hydrogen, a C 1 -C 10 alkyl group, or a cycloalkyl group, or an aryl group, M is titanium, zirconium or hafnium, and Q is chlorine, a methyl group or a phenyl group.
In yet a further embodiment of the invention, the metallocene component incorporates an unsubstituted cyclopentadienyl group and is characterized by the formula:
In formula (8), Ar is a phenyl group or substituted phenyl group, R 1 and R 2 are each independently a hydrogen, a C 1 -C 10 alkyl group, or a cycloalkyl group, or an aryl group, E is a —C— group or an —Si— group, M is titanium, zirconium or hafnium, and Q is chlorine, a methyl group or a phenyl group.
Another embodiment of the invention involves a metallocene catalyst component which incorporates an indenyl group and is characterized by the formula:
In formula (9), Ar is a phenyl group or substituted phenyl group, Ind is an indenyl or substituted indenyl group, E is a —C— group or an —Si— group, each of R 1 and R 2 is a C 1 -C 4 alkyl group, M is titanium, zirconium or hafnium, and Q is chlorine, a methyl group or a phenyl group. In this aspect of the invention, the indenyl group may be a tetrahydroindenyl group which is substituted or unsubstituted.
In another aspect of the invention in which the secondary ligand component L is a fluorenyl group, the metallocene component is characterized by the formula: In formula (10), Flu′ is a fluorenyl or a substituted fluorenyl group, E is a —C— group or an —Si— group, each of R.sup.1 and R.sup.2 is a C.sub.1-C.sub.4 alkyl group, M is titanium, zirconium or hafnium, and Q is chlorine, a methyl group or a phenyl group. Preferably, the fluorenyl group Flu′ in formula (10) is an unsubstituted fluorenyl group or a substituted fluorenyl group wherein the metallocene component exhibits bilateral symmetry. Another embodiment includes a method for the preparation of the bridged cyclopentadienyl fluorenyl metallocene structure including providing a 3,6-disubstituted fluorine, reacting said 3,6-disubstituted fluorene with a brominating agent to produce a 2.7-dibromo-3,6-disubstituted fluorine, reacting said 2,7-dibromo-3,6-disubstituted fluorene in the presence of a palladium based catalyst with an arylboronic acid to produce a 2,3,6,7-substituted fluorene or reacting said 2,7-dibromo-3,6-disubstituted fluorene with a magnesium or zinc-based Grignard reagent characterized by the formula:
R′MX
wherein R′ is a C 1 -C, 20 alkyl, or a C 6 -C 20 alicyclic or aryl group, M is magnesium or zinc, and X is a halogen, to produce a 2,7,3,6-tetrasubstituted fluorene and reacting said 2,3,6,7-substituted fluorene with fulvene, which may be substituted or unsubstituted, to produce a bridged cyclopentadienyl fluorenyl ligand structure.
In yet a further aspect of the invention, there is provided a process for the polymerization of one or more ethylenically unsaturated monomers to produce a corresponding homopolymer or copolymer. In carrying out the polymerization process, there is provided a metallocene catalyst component as characterized by the above formula (3). In addition to the metallocene catalyst component, there is provided an activating cocatalyst component. The catalyst component and the cocatalyst component are contacted in a polymerization reaction zone with an ethylenically unsaturated monomer under polymerization conditions to produce a polymer product which is then recovered from the reaction zone. Preferably, the activating co-catalyst comprises methylalumoxane (MAO) or tri-isobutylalumoxane (TIBAO) or mixtures thereof. Alternatively, the activating co-catalyst can take the form of a noncoordinating anionic type, such as triphenylcarbenium tetrakis(pentafluorophenyl)aluminate or triphenylcarbenium tetrakis(pentafluorophenyl)boronate. Preferably, the ethylenically unsaturated monomer is a C 3+ alpha olefin. More specifically, the alpha olefin is propylene and the polymerization reaction is carried out to produce syndiotactic or isotactic polypropylene.
In a preferred embodiment of the invention, the metallocene component incorporates a cyclopentadienyl group and is characterized by the formula:
In formula (11), Ar is a phenyl group or substituted phenyl group, R 1 and R 2 are each independently a hydrogen, a C 1 -C 10 alkyl group, or a cycloalkyl group, or an aryl group, R 1 is a C 1 -C 4 alkyl group or an aryl group, n is a number from 0 to 4, E is a —C— group or an —Si— group, each of R 1 and R 2 is a C 1 -C 4 alkyl group, M is titanium, zirconium or hafnium, and Q is chlorine, a methyl group, a phenyl group, or a substituted phenyl or benzyl group. In one aspect of this embodiment of the invention, the metallocene component exhibits bilateral symmetry and the polymer product is syndiotactic polypropylene. In another aspect, the metallocene does not exhibit bilateral symmetry and the polymer product is isotactic polypropylene. In a specific embodiment of the process, the metallocene component incorporates an unsubstituted cyclopentadienyl group and is characterized by the formula:
to produce a syndiotactic polypropylene having a melting temperature higher than 150° C. and a crystallization temperature of more than 95° C. Preferably, the syndiotactic polypropylene has a melting temperature greater than 170° C.
DETAILED DESCRIPTION OF INVENTION
The present invention involves bridged transition metal catalysts having metallocene ligand structures incorporating tetra-substituted fluorenyl groups and their use in the polymerization of olefins. Specific olefins which may be polymerized, either through homopolymerization or copolymerization include ethylene, propylene, butylene, as well as monoaromatic or substituted vinyl compounds as described previously. The bridged catalyst components of the present invention incorporate transition metals from Groups 4 or 5 of the Periodic Table of Elements (new notation) and more particularly, transition metals from Group 4 of the Periodic Table of Elements. Preferred transition metals for use in the catalyst components of the present invention are titanium, zirconium and hafnium, with zirconium being particularly preferred.
The catalyst components of the present invention incorporate a primary fluorenyl group that is tetra-substituted fluorenyl group which is bridged to a secondary ligand structure which is a substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl group or a heteroorgano group. The tetra-substituted fluorenyl groups are symmetrical with respect to a plane of symmetry through the bridge and the transition metal. Preferably, the substituents at the 2,7 positions are bulkier than the substituents at the 3,6 positions. However, a reverse relationship of substitution may be employed in some instances. In this case, the primary fluorenyl group may be substituted at the 2- and 7-positions with a C 1 -C 3 alkyl group and at the 3- and 6-positions with a bulky hydrocarbyl group containing at least 4 carbon atoms. More specifically, the catalyst components of the present invention comprise metallocene ligand structures which incorporate tetra-substituted fluorenyl groups substituted at at least the 2,7 and 3,6 positions which are bridged to substituted or unsubstituted cyclopentadienyl, indenyl, fluorenyl or heteroorgano groups and which are characterized in terms of symmetry (or asymmetry) with reference to a plane of symmetry extending through the bridge and the transition metal.
The following diagrams indicate metallocene ligand structures (and the numbering schemes for such structures) which may be employed in carrying out the present invention. Diagram (13) indicates a cyclopentadienyl-fluorenyl ligand structure, diagram (14) an indenyl-fluorenyl ligand structure, diagram (15) a heteroatom (XR)-fluorenyl ligand structure, and diagram (16) a fluorenyl-fluorenyl ligand structure.
The numbering schemes used to indicate the position of substituents on the various ligand structures are indicated on diagrams (13)-(16). With respect to structure (14), while not shown, the indenyl moiety may take the form of 4,5,6,7-tetrahydro indenyl as well as the more common unhydrogenated indenyl group. For each of diagrams (13)-(16), the metallocene ligand structures may be characterized in terms of a plane of symmetry extending perpendicular to the plane of the paper through the bridge group B and the transition metal (not shown) in diagrams (13)-(16) which would project upwardly from the plane of the paper.
As described with respect to various examples given below and with respect, for example, to diagram (13), the cyclopentadienyl group may be monosubstituted and the fluorenyl group may be symmetrically substituted at the 2,7 and 3,6 positions. If there are no other substituents or if the fluorenyl group is otherwise symmetrically substituted, the 3-position is equivalent to the 4-position on the cyclopentadienyl group and this relationship may be expressed by the positional expression 3(4).
The catalysts of the present invention can be advantageously used in propylene polymerization to produce syndiotactic or isotactic polypropylenes with high yields, having high molecular weights, high tacticities and high melt temperatures. Desired features of the catalysts of the present invention are due to a unique combination of structural parameters of the catalysts and substitutions of the cyclopentadienyl and fluorenyl rings. In addition, the catalysts of the present invention can be used in copolymerization of propylene with olefins, e.g. ethylene to yield random or impact copolymers.
Ligand structures suitable for use in carrying out the present invention which can be employed to produce isotactic polypropylene include, with reference to diagram (13), 3-tertiary butyl, 5-methyl cyclopentadienyl, 2,7-ditertiary butyl, 4-phenyl fluorene, the same ligand structure except with substitution on the fluorenyl structure at the 5-position and the same ligand structure with substitution at the 4- or 5-positions by a 4-tertiary butyl phenyl group. In other words, the phenyl group is substituted by a tertiary butyl group at the directly distal position with respect to the substitution of the phenyl group on the fluorenyl group.
Other suitable ligand structures which can be employed to produce isotactic polypropylene include ligand structures such as described above, except the cyclopentadienyl group is mono-substituted at the 3-position with a tertiary butyl group. The fluorenyl group is substituted as before at the 2- and 7-positions with the tertiary butyl groups and at the 4-position with a phenyl group or a 4-tertiary butyl phenyl group.
Similarly substituted ligand structures may be employed in accordance with the present invention incorporating a bis-indenyl fluorenyl ligand structure exemplified by diagram (14). Typically, because of the unbalanced characteristic of the indenyl structure, further substitution of the indenyl (or the 4,5,6,7-tetrahyrdo indenyl) group will not be employed. The fluorenyl ligand component may be substituted as described previously, thus, it may be substituted at the 4-position or di-substituted at the 4- and 5-positions with bulky groups such as tertiary butyl and phenyl groups. Also, the fluorenyl ligand structure may be substituted at one of the 4- and 5-positions and disubstituted at the 2- and 7-positions with substituent groups which are less bulky than the substituents on the 4- or 5-positions.
The heteroatom ligand structure depicted in diagram (15) may be substituted on the fluorenyl group similarly as described above with respect to diagrams (13) and (14). Thus, for example, the fluorenyl group may be substituted at the 2- and 7-positions with tertiary butyl groups and substituted at the 4-position with a substituted or unsubstituted phenyl group. Alternatively, the fluorenyl group may be unsubstituted at the 2- and 7-positions and substituted at the 4-position with an isopropyl group, a tert-butyl group, a phenyl group or a substituted phenyl group.
In employing the catalyst components of the present invention in polymerization procedures, they are used in conjunction with an activating co-catalyst. Suitable activating co-catalysts may take the form of co-catalysts such are commonly employed in metallocene-catalyzed polymerization reactions. Thus, the activating co-catalyst may take the form of an aluminum co-catalyst. Alumoxane co-catalysts are also referred to as aluminoxane or polyhydrocarbyl aluminum oxides. Such compounds include oligomeric or polymeric compounds having repeating units of the formula:
where R is an alkyl group generally having 1 to 5 carbon atoms. Alumoxanes are well known in the art and are generally prepared by reacting an organo-aluminum compound with water, although other synthetic routes are known to those skilled in the art. Alumoxanes may be either linear polymers or they may be cyclic, as disclosed for example in U.S. Pat. No. 4,404,344. Thus, alumoxane is an oligomeric or polymeric aluminum oxy compound containing chains of alternating aluminum and oxygen atoms whereby the aluminum carries a substituent, preferably an alkyl group. The structure of linear and cyclic alumoxanes is generally believed to be represented by the general formula —(Al(R)—O-)-m for a cyclic alumoxane, and R 2 Al—O—(Al(R)—O)m-AlR 2 for a linear compound wherein R independently each occurrence is a C 1 -C 10 hydrocarbyl, preferably alkyl or halide and m is an integer ranging from 1 to about 50, preferably at least about 4. Alumoxanes also exist in the configuration of cage or cluster compounds. Alumoxanes are typically the reaction products of water and an aluminum alkyl, which in addition to an alkyl group may contain halide or alkoxide groups. Reacting several different aluminum alkyl compounds, such as, for example, trimethylaluminum and tri-isobutylaluminum, with water yields so-called modified or mixed alumoxanes. Preferred alumoxanes are methylalumoxane and methylalumoxane modified with minor amounts of other higher alkyl groups such as isobutyl. Alumoxanes generally contain minor to substantial amounts of the starting aluminum alkyl compounds. The preferred co-catalyst, prepared either from trimethylaluminum or tri-isobutylaluminum, is sometimes referred to as poly (methylaluminum oxide) and poly (isobutylaluminum oxide), respectively.
The alkyl alumoxane co-catalyst and transition metal catalyst component are employed in any suitable amounts to provide an olefin polymerization catalyst. Suitable aluminum transition metal mole ratios are within the range of 10:1 to 20,000:1 and preferably within the range of 100:1 to 5,000:1. Normally, the transition metal catalyst component and the alumoxane, or other activating co-catalyst as described below, are mixed prior to introduction in the polymerization reactor in a mode of operation such as described in U.S. Pat. No. 4,767,735 to Ewen et al. The polymerization process may be carried out in either a batch-type, continuous or semi-continuous procedure, but preferably polymerization of the olefin monomer (or monomers) will be carried out in a loop type reactor of the type disclosed in the aforementioned U.S. Pat. No. 4,767,735. Typical loop type reactors include single loop reactors or so-called double loop reactors in which the polymerization procedure is carried in two sequentially connected loop reactors. As described in the Ewen et al. patent, when the catalyst components are formulated together, they may be supplied to a linear tubular pre-polymerization reactor where they are contacted for a relatively short time with the pre-polymerization monomer (or monomers) prior to being introduced into the main loop type reactors. Suitable contact times for mixtures of the various catalyst components prior to introduction into the main reactor may be within the range of a few seconds to 2 days. For a further description of suitable continuous polymerization processes which may be employed in carrying out the present invention, reference is made to the aforementioned U.S. Pat. No. 4,767,735, the entire disclosure of which is incorporated herein by reference.
Other suitable activating co-catalysts which can be used in carrying out the invention include those catalysts which function to form a catalyst cation with an anion comprising one or more boron atoms. By way of example, the activating co-catalyst may take the form of triphenylcarbenium tetrakis(pentafluorophenyl) boronate as disclosed in U.S. Pat. No. 5,155,080 to Elder et al. As described there, the activating co-catalyst produces an anion which functions as a stabilizing anion in a transition metal catalyst system. Suitable noncoordinating anions include [W(PhF 5 )] − , [Mo(PhF 5 )] − (wherein PhF 5 is pentafluorophenyl), [ClO 4 ] − , [S 2 O 6 ] − , [PF 6 ] − , [SbR 6 ] − , [AlR 4 ] − (wherein each R is independently Cl, a C 1 -C 5 alkyl group preferably a methyl group, an aryl group, e.g. a phenyl or substituted phenyl group, or a fluorinated aryl group). Following the procedure described in the Elder et al. patent, triphenylcarbenium tetrakis(pentafluorophenyl)boronate may be reacted with pyridinyl-linked bis-amino ligand of the present invention in a solvent, such as toluene, to produce a coordinating cationic-anionic complex. For a further description of such activating co-catalyst, reference is made to the aforementioned U.S. Pat. No. 5,155,080, the entire disclosure of which is incorporated herein by reference.
In addition to the use of an activating co-catalyst, the polymerization reaction may be carried out in the presence of a scavenging agent or polymerization co-catalyst which is added to the polymerization reactor along with the catalyst component and activating co-catalyst. These scavengers can be generally characterized as organometallic compounds of metals of Groups 1A, 2A, and 3B of the Periodic Table of Elements. As a practical matter, organoaluminum compounds are normally used as co-catalysts in polymerization reactions. Specific examples include triethylaluminum, tri-isobutylaluminum, diethylaluminum chloride, diethylaluminum hydride and the like. Co-catalysts normally employed in the invention include methylalumoxane (MAO), triethylaluminum (TEAL) and tri-isobutylaluminum (TIBAL).
The bridged fluorenyl ligand structures and the corresponding transition metal catalyst components can be prepared by any suitable techniques. Typically, for methylene bridged cyclopentadienyl fluorenyl ligand structures, the fluorenyl group is treated with methyl lithium to result in a fluorenyl group substituted with lithium in the 9-position and this is then reacted with a 6,6-substituted fulvene. For example, 6,6-dimethyl fulvene may be employed to produce the isopropylidene cyclopentadienyl substituted fluorenyl ligand structure. For a ligand structure in which the bridge group incorporates a germanium or silicon atom, the lithiumated fluorenyl group is reacted, for example, with diphenylsilyl dichloride to produce the diphenylsilyl chloride substituent at the 9-position on the fluorenyl group. This component is then reacted with the lithiumated cyclopentadienyl or substituted cyclopentadienyl to produce the bridge. The ligand structure is then treated with methyl lithium, followed by reaction with the appropriate transition metal, chlorine, e.g. zirconium tetrachloride, to produce the corresponding metallocene dichloride.
The catalyst components employed in the present invention can be prepared by techniques, which include procedures well-known in the art with appropriate modification of the fluorenyl ligand component to incorporate a 2,7,3,6-tetra-substituted fluorene. For example, as described below, 6,6-dimethyl fulvene can be employed in conjunction with 2,7,3,6 symmetrically substituted fluorene in order to produce the corresponding methylene-bridged cyclopentadienyl 2,7,3,6-tetra-substituted fluorene. The fluorenyl-fluorenyl ligand structures employed in the present invention can be synthesized using a procedure such as disclosed in U.S. Pat. No. 6,313,242 to Reddy to form bis-fluorenyl ligands, again with the qualification that a symmetrical ligand structure rather than the staggered ligand structure of the type disclosed in Reddy will be produced. Similarly, a bridged fluorenyl heteroatom ligand structure of the type characterized by formula 10 above can be produced by preparation of a substituted fluorene with dimethyldichlorosilane, followed by reaction with a tertiary butyllithiumamide to produce the bridged fluorenyl amine structure. Again, the above procedure would be followed, but with the modification to employ, for example, 2,7-diphenyl,3,6-ditertiary butyl fluorene rather than the 3,6-ditertiary butyl fluorene disclosed in the Reddy patent. The various procedures which can be used in the synthesis of the metallocene components of the present invention are illustrated by the synthesis procedures described below.
One embodiment of the present disclosure includes a method for the preparation of a bridged cyclopentadienyl fluorenyl metallocene structure comprising:
(a) providing a 3,6-disubstituted fluorene characterized by the formula:
wherein:
R is a branched alkyl group having from 1 to 20 carbon atoms or a cyclic alkyl having from 5 to 20 carbon atoms;
(b)reacting said 3,6-disubstituted fluorene with a brominating agent to produce a 2,7-dibromo-3,6-disubstituted fluorene characterized by the formula:
(c) reacting said 2,7-dibromo-3,6-disubstituted fluorene in the presence of a palladium based catalyst with an arylboronic acid characterized by the formula:
wherein:
Ar is a phenyl group or a naphthyl group; to produce a 2,3,6,7-substituted fluorene characterized by the formula:
or;
(d) reacting said 2,7-dibromo-3.6-disubstituted fluorene with a magnesium or zinc-based Grignard reagent characterized by the formula:
R′MX
wherein:
R′ is a C 1 -C 20 alkyl, or a C 6 -C 20 alicyclic or aryl group, M is magnesium or zinc, and X is a halogen, to produce a 2,7,3,6-tetrasubstituted fluorene characterized by the formula:
wherein:
R′ and R are as defined above;
(e) reacting said 2,3,6,7-substituted fluorene with fulvene, which may be substituted or unsubstituted, to produce a bridged cyclopentadienyl fluorenyl ligand structure characterized by the formula:
wherein:
R″ is a C 1 -C 20 alkyl group or an aryl group;
n is a number from 0-4; and
R 1 and R 2 are each independently a hydrogen, a C 1 -C 10 alkyl group or a cycloalkyl or an aryl group; and
(f) reacting the bridged cyclopentadienyl flourenyl ligand structure with a transition metal/halogen compound to form the bridged cyclopentadienyl fluorenyl metallocene structure.
In another embodiment, the Ar is a phenyl group or substituted phenyl group. In still another embodiment, R is a tertiary butyl group. In still another embodiment, the fulvene is unsubstituted 6,6-dimethylfulvene to produce said methylene-bridged cyclopentadienylfluorenyl ligand structure in which n is 0. In yet another embodiment, the fulvene is unsubstituted 6-alkyl (or aryl) fulvene to produce said cyclopentadienylfluorenyl component with C(H)Alkyl or C(H)Aryl bridge in which n is 0. In still yet another embodiment, the 3,6-disubstituted fluorene is a 3,6-di-tertiaybutylfluorene wherein said cyclopentadienylfluorenyl metallocene structure is characterized by the formula:
wherein R″ is a C 1 -C 20 alkyl group or an aryl group; and n is a number from 0 to 4; and R 1 and R 2 are each independently a hydrogen, a C 1 -C 10 alkyl group, or a cycloalkyl group, or an aryl group. In still yet another embodiment, the fulvene is substituted at the 2-position with a tertiary butyl group and at the 4-position with a methyl group, wherein said methylene-bridged cyclopentadienylfluorenyl metallocene structure is characterized by the formula:
wherein R′ is a C 1 -C 4 alkyl group or an aryl group. In another embodiment, wherein the fulvene is substituted at the 2-position with a tertiary butyl group and at the 4-position with a methyl group, R′ is a phenyl group.
Specific metallocenes embodying the present invention are illustrated by the following structural formulas in which the isopropylidene bridge group is illustrated by and a tertiary butyl group is indicated by .
1. Synthesis of Catalysts
2,7-Dibromo-3,6-di-t-butyl-fluorene was synthesized by the reaction of 3,6-di-t-butyl-fluorene with N-bromo succinimide in propylene carbonate solution in 82% yield in accordance with the following reaction and used as a starting material for the synthesis of 2,7-di-aryl-3,6-di-tert-butyl-fluorenes for catalysts M1-M15:
The coupling reaction of 2,7-dibromo-3,6-di-t-butyl-fluorene with phenyl boronic acid provided 2,7-phenyl-3,6-di-t-butyl-fluorene in 90% yield in accordance with the following reaction:
EXAMPLE 1
Synthesis of 2,7-Dibromo-3,6-di-t-butyl-fluorene
To a solution of 3,6-di-t-butylfluorene (2.10 g, 7.55 mmol) in propylene carbonate (60 ml) was added 2.70 g of N-bromosuccinimide. The reaction mixture was stirred for 6 hours at 70-75° C. The mixture was poured into water and the precipitated solid was filtered, washed with water and dried to produce a yield of 2.71 g (82%). 1 H NMR (CDCl 3 ): δ 7.80 and 7.72 (each s, 2H, 1,8- and 4,5-H (Flu), 3.74 (s, 2H, H9), 1.59 (s, 18H, t-Bu)
The coupling reaction of 2,7-dibromo-3,6-di-t-butyl-fluorene with aryl boronic acid produced 2,7-aryl-3,6-di-t-butyl-fluorene in an 85-95% yield in accordance with the following reaction:
EXAMPLE 2
Synthesis of 2,7-Diphenyl-3,6-di-t-butyl-fluorene
To a mixture of 2,7-dibromo-3,6-di-t-butylfluorene (0.96 g, 2.20 mmol) and Pd(PPh 3 ) 4 (260 mg, 0.22 mmol) in toluene (50 ml) was added a solution of phenylboronic acid (0.81 g, 6.63 mmol) in EtOH (10 ml) and a solution of Na 2 CO 3 (1.5 g) in water (10 ml). The reaction mixture was stirred for 6 hours under reflux. The reaction mixture was quenched with water, extracted with ether, dried over MgSO 4 , and evaporated under vacuum to afford the residue which was purified by column chromatography (silica gel, hexane/CH 2 Cl 2 =5/1) to produce 2,7-diphenyl-3,6-di-t-butyl-fluorene (0.85 g, ˜90%). 1 H NMR (CDCl 3 ): δ 7.96 and 7.15 (each s, 2H, 1,8- and 4,5-H (Flu), 7.33 (m, 10H, Ph), 3.77 (s, 2H, H9), 1.27 (s, 18H, t-Bu).
EXAMPLE 3
Synthesis of 2,7-Di(4-tert-butyl-phenyl)-3,6-di-t-butyl-fluorene
The same procedure as in Example 2 was used except 4-tert-butyl-phenyl-boronic acid was used in place of phenylboronic acid. The yield was 92%.
The following Examples 4 and 5 illustrate the preparation of 2,7-dimethyl-3,6-di-tert-butyl-fluorene.
EXAMPLE 4
Synthesis of 2,7-dichloromethane-3,6-di-tert-butyl-fluorene
To a solution of 3,6-di-t-butylfluorene (2.00 g, 7.19 mmol) and chloromethyl methyl ether (2.5 ml) in CS 2 (15 ml) was added at 0° C. a solution of TiCl 4 (0.4 ml) in CS 2 (5 ml). The reaction mixture was stirred for 3 hours at room temperature. The mixture was poured into ice water and extracted with ether. The ether extract was dried over sodium sulfate and evaporated under vacuum to leave a residue, which was purified by column chromatography (hexane/CH 2 Cl 2 =10/1) and crystallization from hot heptanes. The product provided 2-chloromethyl-3,6-di-t-butylfluorene (yield 0.75 g). 1 H NMR (CDCl 3 ): δ 7.80 and 7.78 (each d, 1H, 4,5-H), 7.47 (d, 1H, J=8.1 Hz, H8), 7.34 (dd, 1H, J=8.1 Hz, J=1.5 Hz, H7), 7.31 (d, 1H, 1H, J=1.5 Hz, H1), 4.72 (s, 2H, CH 2 Cl), 3.87 (s, 2H, H9), 1.41 (s, 18H, t-Bu) and 2,7-dichloromethyl-3,6-di-t-butylfluorene (yield 0.63 g). 1 H NMR (CDCl 3 ): δ 7.87 (br s, 2H, 4,5-H), 7.34 (br s, 2H, 1,8-H), 4.75 (s, 4H, CH 2 Cl), 3.95 (s, 2H, H9), 1.42 (s, 18H, t-Bu) as indicated by the following reaction:
EXAMPLE 5
Reduction of 2,7-dichloromethane-3,6-di-tert-butyl-fluorene
To a solution of 2,7-di-chloromethyl-3,6-di-t-butylfluorene (0.75 g) in THF (15 ml) was added a small portion of LiAlH 4 (0.25 g) under stirring. The mixture was refluxed for 5 hours. The reaction was quenched with water and NaOH, and extracted with ether. The ether solution was evaporated under vacuum to produce a white solid with a yield of 0.69 g.
Examples 6 and 7 illustrate the synthesis of 2,2-[(cyclopentadienyl)-(2,7-di-phenyl-3,6-di-tert-butylfluorenyl)]-isopropylidene zirconium dichloride (catalyst component M1).
EXAMPLE 6
2,2-[(Cyclopentadienyl)-[(2,7-di-phenyl-3,6-di-tert-butylfluorenyl)]-propane
Butyllithium (1.5 ml, 1.6M in hexane, 2.40 mmol) was added to 2,7-diphenyl-3,6-di-t-butyl-fluorene (0.95 g, 2.20 mmol) in THF (20 ml) at −78° C. The reaction mixture was allowed to warm to room temperature and stirred for 2.5 hours. The solvent was removed under vacuum. Ether (5 ml) was added and removed under vacuum. Ether (25 ml) was added and 6,6′-dimethylfulvene (0.23 g, 2.43 mmol) in ether (5 ml) was added to the reaction mixture at 0° C. The reaction was stirred at room temperature for 5 days. The reaction mixture was quenched with water, extracted with ether, dried over MgSO 4 , and evaporated under vacuum to afford the residue which was purified by column chromatography (silica gel, hexane/CH 2 Cl 2 =5/1) and crystallized from hot hexane. The yield was 0.40 g, 34%. 1 H NMR (CDCl 3 ): δ 7.91 and 7.30 (each s, 2H, 1,8- and 4,5-H (Flu), 7.35 (m, 10H, Ph), 6.76, 6.40 (m, 3H, Cp), 4.04 and 4.02 (s 2H, H9), 3.00 and 2.78 (br s, 2H, CH2 Cp), 1.31 (s, 18H, t-Bu), 1.11 and 1.09 (s, 6H, Me). 1 H NMR (CD 2 Cl 2 ): δ 7.91 and 7.29 (each s, 2H, 1,8- and 4,5-H (Flu), 7.2-7.4 (m, 10H, Ph), 6.8-6.7, 6.40 (m, 3H, Cp), 4.02 (brs, 2H, H9), 3.00 and 2.78 (br s, 2H, CH2 Cp), 1.28 (s, 18H, t-Bu), 1.07 and 1.04 (s, 6H, Me). HPLC: 10.38 and 10.65 min.
EXAMPLE 7
2,2-[(Cyclopentadienyl)-(2,7-di-phenyl-3,6-di-tert-butylfluorenyl)]-propane zirconium dichloride (catalyst M1)
Butyllithium (1.0 ml, 1.6M in Et 2 O, 1.60 mmol) was added to 2,2-[(cyclopentadienyl)-[(2,7-di-phenyl-3,6-di-tert-butylfluorenyl)]-propane (0.39 g, 0.73 mmol) in THF (10 ml) at −78° C. The reaction mixture was allowed to warm to room temperature and stirred for 2.5 hours. The solvent was evaporated under vacuum. Ether (5 ml) was added and removed under vacuum. ZrCl 4 (0.170 g, 0.76 mmol) was added. at −78°. Ether (10 ml) was added to reaction mixture. The reaction mixture was allowed to warm to room temperature and stirred for 5 hours. The solvent was removed under vacuum to afford an orange solid, which was tested in propylene polymerization without purification. 1 H NMR (C 6 D 6 ): δ 8.14 (s, 2H, Flu-1,8), 7.4-7.2 (m, 12H, Ph, Flu-5,6), 6.04 and 5.69 (each m, 2H, Cp), 1.33 (s, 18H, t-Bu).
Examples 8-10 illustrate the synthesis of (4-tert-butyl-phenyl)[(cyclopentadienyl)(2,7-di-phenyl)-(3,6-di-tert-butyl-fluorenyl)]methane zirconium dichloride (catalyst M12).
EXAMPLE 8
6-(4-tetr-butyl-Phenyl)-5-methyl-3-tert-butyl-fulvene
To a solution of methyl-tert-butylcyclopentadiene (4.42 g, 32.5 mmol) and 4-t-butyl-benzaldehyde (5.15 g) in absolute ethanol (30 ml) was added a small portions of sodium methoxide (4.0 g) under stirring. The mixture was stirred for 2 hours. The reaction was quenched with water and extracted with ether. The ether solution was evaporated under vacuum to give an orange liquid, which was purified by column chromatography (silica gel, hexane/CH 2 Cl 2 =8/1), providing a yield of 7.0 g. 1 H NMR (CDCl 3 ): δ 7.55 (m, 2H, Ph), 7.48 (m, 2H, Ph), 7.02 (s, 1H, H—CPh), (m, 1H, H-6), 6.27 and 6.22 (br s, 2H, H—Cp), 2.18 (s, 3H, Me), 1.39 and 1.23 earh (s, 9H, t-Bu).
EXAMPLE 9
(4-tert-butyl-phenyl)[(cyclopentadienyl)-[(2,7-di-phenyl-3,6-di-tert-butylfluorenyl)]-methane
Butyllithium (1.5 ml, 1.6M in hexane, 2.40 mmol) was added to 2,7-diphenyl-3,6-di-t-butyl-fluorene (1.02 g, 2.33 mmol) in ether (20 ml) at −78° C. The reaction mixture was allowed to warm to room temperature and stirred for 2.5 hours. 6-(4-tert-Butyl-phenyl)-fulvene (0.49 g, 2.33 mmol) in ether (5 ml) was added to the reaction mixture at −20° C. The reaction was stirred at room temperature for 2 hours. The reaction mixture was quenched with water, extracted with ether, dried over MgSO 4 , and evaporated under vacuum to afford the residue, which was washed with hot ethanol.
EXAMPLE 10
(4-tert-Butyl-phenyl)[(cyclopentadienyl)(2,7-di-phenyl)-(3,6-di-tert-butyl-fluorenyl)]methane zirconium dichloride (catalyst M12)
Butyllithium (1.3 ml, 1.6M, 2.08 mmol) was added to (4-tert-butyl-phenyl)[(cyclopentadienyl)(2,7-di-phenyl)-(3,6-di-tert-butyl-fluorenyl)]methane (0.61 g, 0.95 mmol) in ether (10 ml) at −78° C. The reaction mixture was allowed to heat to room temperature and the reaction was continued for 2.5 hours. The solvent was removed under vacuum. ZrCl 4 (220 mg) was added to the reaction mixture. Toluene (15 ml) was added at −20° C. and the reaction was stirred at room temperature for night. The solvent was removed under vacuum.
Catalysts M2-M11 and M13-M18 can be prepared as described in the foregoing Examples through the use of the corresponding 2,7-di-substituted-3,6-tert-butyl-fluorene and fulvene.
EXAMPLES 11-17
Homogeneous Polymerization with Catalyst M1
The polymerization was conducted in bulk propylene at 40, 60 and 70° C. in a 4L reactor using the crude catalyst from Reaction 21 without purification. The polymerization behavior for the catalyst is set forth in Tables 1 through 3. The catalyst produced a polymer with activity of 30,000 gPP/gcat/h at 60° C. without hydrogen. In the presence of hydrogen (60 ppm) the activity increased up to 142,400 gPP/gcat/h. The catalyst produced syndiotactic polypropylene with pentad rrrr values of 85-92% (Table 4), melting temperature of 149-163° C. and molecular weight of 130,000-230,000 (Table 3). A broader molecular weight distribution (D) was also observed due to the presence of a low molecular weight fraction, a content of which could be decreased by fraction extraction of the polymer. Fraction extraction of the sample with hot hexane for 3 hours provided a polymer with a narrow molecular weight distribution (D=1.9), melting temperature of 153° C. and tacticity of 92% of rrrr pentad.
TABLE 1
Bulk Propylene Polymerization with Unsupported Catalyst M1
Catalyst
T,
Time,
H 2 ,
Activity,
MFR,
Example
mg
° C.
min
ppm
PP, g
gPP/g cat/h
dg/min
11 a
20
−10
180
0
2.0
12
7.0
40
60
0
42
6,000
13
10
60
30
0
150
30,000
3.6
14 b
15 c
16
5.5
60
10
60
130
142,390
4.3
17
4.3
70
30
0
10
4,650
a Polymerization at 1 atmosphere of propylene in toluene
b Crystallized fraction from xylene of sample 13
c Heptane extraction of sample 14
TABLE 2
DSC Data of Polypropylene
T melt,
T cryst,
Delta H
Delta H
Example
° C.
° C.
melt, J/g
recryst, J/g
11
163.0
109.0
29.6
−39.3
12
160.4
98.6
37.0
−97.9
13
149.4
89.6
46.3
−59.6
14
15
152.7
97.6
44.7
−49.0
16
154.4
109.6
40.8
−109.6
17
146.0
101.0
29.2
−48.9
TABLE 3
GPC Data of Polypropylene
Example
Mn
Mw
Mz
D
D′
11
7,909
222,922
1211,160
28 a
5.4
12
6,394
169,439
510,047
26.5 a
3.0
13
31,719
161,604
324,372
5.1
2.0
14
45,600
166,100
338,760
3.6
2.0
15
96,447
186,871
335,371
1.9
1.8
16
27,298
149,743
285,755
5.5
1.9
17
26,940
129,260
254,190
4.8
2.0
a bimodal
TABLE 4
Pentad Distributions for Syndiotactic Polypropylene
Example
Example
Example
Example
Example
12
13
14
16
17
mmmm %
2.1
0.3
0.3
0.4
0.4
mmmr
4.4
0.6
0.0
0.8
0.5
rmmr
2.5
0.8
0.6
1.0
1.0
mmrr
3.3
1.3
0.9
1.4
1.5
xmrx
9.2
3.0
1.5
3.2
4.0
mrmr
5.8
1.4
0.0
1.4
0.8
rrrr
65.2
87.5
92.0
86.3
84.9
rrrm
4.0
3.7
3.8
4.1
5.7
mrrm
3.6
1.4
0.9
1.3
1.2
% meso
18.2
4.6
2.1
5.3
5.1
% racemic
81.8
95.4
97.9
94.7
94.9
% error
7.1
2.3
1.4
2.6
3.0
def/1000° C.
90.9
22.8
10.4
26.5
25.3
EXAMPLE 18-25
Homogeneous Polymerization with Catalyst M12
The polymerizations in Examples 18-20 were conducted in bulk propylene using 10×-Multi-Clave reactor from Autoclave Engineers in 5 ml of bulk propylene in 30 ml glass vessels. The catalyst was activated with MAO (Zr/Al=1/1000-2000) prior to polymerization.
TABLE 5
Propylene polymerization with Catalyst M12 in 10X Multi-Clave reactors (bulk propylene,
homogeneous, 60° C., 30 min, no H 2 )
Catalyst
Activity,
Tmelt,
Tcryst,
Mw/
Mw/
Mz/
Example
(mg)
T°, C
Polymer, g
g/g//h
° C.
° C.
1000
Mn
Mw
18
0.15
50-60
1
13,300
158.7
96.3
206.7
2.6
1.9
19
0.45
40-50
3.6
10,526
161.9
99.0
278.8
2.9
1.8
20
0.9
20
5.7
6,333
160.0
96.3
300.0
2.6
1.8
a The highest melting peak
EXAMPLE 21
Propylene Polymerization under 1 atm with Catalyst M12
The propylene polymerization in Example 21 was conducted with 1.3 mg of catalyst M12, activated with 2 ml of 30% MAO, using the glass reactor under 1 atm of propylene in toluene solution at −10° C. for 3 hours. 1.6 g of polypropylene was isolated. Tmelt=171° C., T cryst=112.3° C., Mw=446,200, Mw/Mn=3.0, Mz/Mw=1.9.
TABLE 6
Tacticity of polypropylene samples
Example
Example
Example
TACTICITY, %
20
19
21
mmmm
0.1
0.2
2.5
mmmr
0.3
0.0
1.1
rmmr
0.3
0.2
0.2
mmrr
0.6
0.5
0.4
xmrx
0.8
0.4
1.0
mrmr
0.2
0.0
0.1
rrrr
89.7
94.6
90.7
rrrm
6.1
3.2
3.0
mrrm
1.9
0.9
1.1
% meso
1.5
0.8
4.5
% racemic
98.5
99.2
95.5
% error
0.7
0.3
0.7
def/1000 C.
7.4
4.2
22.3
The polymerizations in Examples 22-25 were conducted in bulk propylene using a 2L Zipper-Clave reactor from Autoclave Engineers. The reactor was charged with 300 g of bulk propylene prior to polymerization. The catalyst was activated with MAO (Zr/Al=1/1000-2000) prior to polymerization.
TABLE 7 Bulk propylene polymerization with Catalyst M12 under homogeneous condition Catalyst T, H2, Activity, Tm, MF, Mw/ Mw/ Mz/ % Tol Example (mg) ° C. ppm Polymer, g g/g//h ° C. g/10 min 1000 Mn Mw Sol 22 0.3 50 30 56 373,333 159.7 1.0 219.8 2.6 1.8 0.5 23 0.5 60 60 65 260,000 157.7 1.9 173.4 2.2 1.8 0.9 24 0.2 60 30 53 530,000 155.7 1.5 176.9 2.2 1.8 25 1.5 70 60 146 195,000 153.4 3.2 154.0 2.5 1.9 0.6
As can be seen from Examples 18-25, catalyst M12 produced syndiotactic polypropylene with pentad rrrr values of 88-95%, melting temperatures of 153-171° C., molecular weights of 154,000-300,000 at activities up to 530,000 gPP/Gcat/h.
EXAMPLES 26-29
Propylene Polymerization with Supported Catalyst M1
The catalyst M1 was supported on a silica support available from Asahi Glass Co., Ltd. under the designation H-121. The silica support had an average particle size of 12 microns. The catalyst supported on the silica with a 2 wt. % loading was tested at 60° C. for 1 hour in a 4 L reactor. The polymerization behavior for the unsupported catalyst is set forth in Tables 8 and 9. The hydrogen response of the supported catalyst was tested. The hydrogen response of the supported catalyst showed that the catalyst activity increased as the hydrogen levels increased (Table 8). The melting temperature of polymers produced in the presence of hydrogen was around 136-137° C. and is slightly dependent on hydrogen concentration. The molecular weight of the polymers showed a range of 99,000-78,000 for hydrogen levels of 0-75 ppm. In addition, the melt flow rate slightly increased from 31-44 g/10 min. with increasing the hydrogen concentration from 40 to 75 ppm. The supported catalyst produced a polymer with a narrow molecular weight distribution (D=2.1-2.6). Polymer produced using the supported catalyst showed good stereoregularity (% rrrr=82-83 in the presence of hydrogen) (Table 9).
TABLE 8
Polymerization Test Results for Supported Catalyst M1
Cat
T,
Time,
H2,
Activity,
MFR,
Example
mg
° C.
min
ppm
PP, g
gPP/g cat/h
dg/min
T melt, ° C.
Mn
Mw
Mz
D
D′
26
40*
60
60
0
4
100
127.7
38,967
99,373
166,385
2.6
1.7
27
40*
60
60
40
25
625
31
137.2/120.9
37,442
78,308
129,672
2.1
1.7
28
20*
60
60
60
13
650
39
136.0/119.6
35,644
82,217
140,208
2.3
1.7
29
40*
60
60
75
31
775
44
137.2/120.9
37,442
78,308
129,672
2.1
1.7
TABLE 9
Pentad Distributions for Syndiotactic Polypropylene
Produced with Supported Catalyst
Example
Example
26
27
Example 28
Example 29
mmmm %
0.4
0.1
0.2
0.0
mmmr
0.3
0.2
0.2
0.2
rmmr
1.2
1.3
1.3
1.3
mmrr
2.1
2.1
2.1
2.2
xmrx
4.6
4.5
4.6
4.3
mrmr
0.4
0.4
0.2
0.3
rrrr
77.9
82.3
82.6
83.2
rrrm
8.1
7.8
7.9
7.4
mrrm
5.0
1.2
1.1
1.1
% meso
5.4
5.2
5.1
4.9
% racemic
94.6
94.8
94.9
95.1
% error
3.5
3.5
3.6
3.4
def/1000° C.
17.5
17.7
17.8
17.2
EXAMPLES 30-33
Propylene Polymerization with Supported Catalyst M12
The catalyst M12 was supported on silica supports available from Asahi Glass Co., Ltd. under the designation H-121 and G952. The catalyst supported on the silica with a 2 wt. % loading was tested at 60° C. for 30 minutes in 500 ml stainless reactor. The results in terms of polymerization parameters and polymer properties are shown in Tables 10 and 11.
TABLE 10
Propylene polymerization with Supported Catalyst M12
H2,
Activity,
Tm,
Tc,
Mw/
Mw/
Mz/
Entry #
Support
Run #
ppm
Polymer, g
g/g/cat/h
° C.
° C.
1000
Mn
Mw
30
G952
1137-
10
6.1
610
142.0/
89.3
105
2.5
1.8
099-R3
128.3
31
G952
1137-
60
7
700
142.4
89.3
96
2.8
1.9
099-R4
32
H-121-C
1137-
10
1.8
180
139.0
87.3
105
2.7
1.8
099-R5
33
H-121-C
1137-
60
3
300
141.4
86.6
96
2.5
1.8
099-R6
TABLE 11
Tacticity of polypropylene produced with supported Catalyst M12
Example
Example
31
33
mmmm, %
0.4
0.4
mmmr
0.3
0.3
rmmr
0.8
0.8
mmrr
1.9
1.8
xmrx
3.3
3.4
mrmr
0.5
0.0
rrrr
90.4
83.2
rrrm
1.9
8.1
mrrm
0.7
1.8
% meso
4.2
4.2
% racemic
95.8
95.8
% error
2.4
2.6
def/1000° C.
21.2
20.9
Having described specific embodiments of the present invention, it will be understood that modifications thereof may be suggested to those skilled in the art, and it is intended to cover all such modifications as fall within the scope of the appended claims. | Catalyst compositions and processes for the polymerization of ethylenically unsaturated monomers to produce polymers, including copolymers or homopolymers. Such monomers include ethylene, C 3+ alpha olefins and substituted vinyl compounds, such as styrene and vinyl chloride. The polymerization catalyst characterized by the formula B(FluL)MQ n in which Flu is a fluorenyl group substituted at at least the 2,7- and 3,6-positions by hydrocarbyl groups, preferably relatively bulky hydrocarbyl groups. L is a substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl group or a heteroorgano group, XR, in which X is a heteroatom from Group 15 or 16 of the Periodic Table of Elements, such as nitrogen, R is an alkyl group, a cycloalkyl group or an aryl group and B is a structural bridge extending between the groups L and Flu, which imparts stereorigidity to the ligand structure, M is a Group 4 or Group 5 transition metal, such as titanium, zirconium or hafnium and Q is selected from the group consisting of chlorine, bromine, iodine, an alkyl group, an amino group, an aromatic group and mixtures thereof, with n being 1 or 2. |
BACKGROUND OF THE INVENTION
Field of the Invention
This is a division of application Ser. No. 613,347, filed Sept. 15, 1975, now U.S. Pat. No. 4,068,436, which is a continuation-in-part of application Ser. No. 385,166, filed Aug. 2, 1973, now U.S. Pat. No. 4,048,776.
This invention relates to a steel column base plate member for connecting an H-shaped steel column member of a steel structure to concrete foundation therefor.
Description of the Prior Art
Steel column members of architectural buildings or construction structures are connected to concrete foundations, by means of base plates. It is well known that the steel column is stronger than the concrete of the foundation by a factor of not smaller than 10. To compensate for such difference of the strength between the concrete of the foundation and the steel column, the lower end of the column is joined to a steel plate, and the base plate is secured to the concrete foundation by means of anchor bolts embedded in the concrete foundation.
It has been suggested to provide a base for a column having a recess adapted to accommodate the lower end of the column as shown in U.S. Pat. No. 134,269 issued to J. Gray on Dec. 24, 1872. This base is formed at its center with the recess to reduce its thickness at the center so that the strength against a vertical force may become insufficient to support a load.
It has also been suggested to fit a foot within a lower end of a column which is then inserted into a bed plate with a sleeve or socket to bring the foot into contact with the bed-plate, disclosed for example as in U.S. Pat. No. 198,072 issued to A. Bonzano on Dec. 11, 1877. This bed-plate will support a vertical force but insufficient to support a bending moment transmitted from the column which will probably been supported by the sleeve.
It has also been suggested to provide a base-socket having a supporting base member and an upwardly projecting portion containing a recess to receive the lower end of a column which is secured within the socket by riveting or the like. Such a socket has been disclosed in the U.S. Pat. No. 1,258,409 issued to T. Hill on Mar. 5, 1918. However, the socket has a configuration prone to give rise to a stress concentration and fails in smooth stress transmission through the socket from the column to a concrete foundation.
Generally speaking, the base plate member is required to fulfill the following conditions.
(1) Since the base plate will be subjected to various severe forces resulting from axial force, shearing force and bending moment acting upon the column member, the base plate must be in a configuration to avoid any stress concentration and perform a smooth stress transmission from the column member to the foundation.
(2) In order to decrease the cost of a construction as a whole, the working of column member should be minimized only to cutting of both ends thereof. If any grooves for welding are required, the base plate member should be formed with such grooves by the use of means of minimum possible cost.
(3) If utilizing any welding method for connecting the base plate member to a column member, the base plate member should be of a configuration capable of applying the most effective welding method which is higher in reliability, minimum of consumed welding rods and carried out with ease. The configuration is also applicable of a combination of welding methods of which characteristics help each other to accomplish the most rational arrangement which meets stresses derived from forces and bending moments to which the column member is subjected.
(4) The base plate member should be a configuration in agreement with a stress distribution acting thereupon resulting from axial and shearing forces and bending moment to which the column member is subjected.
(5) The base plate member should be such a configuration that a base portion of the base plate member in contact with a concrete foundation will not be affected by heating derived from welding of the plate member with the column member.
(6) The base plate member should be economical of manufacture and serve to decrease the cost of a construction as a whole
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a steel column base plate member for connecting an H-shaped steel column member to a concrete foundation which overcomes the above disadvantages in the prior art and fulfills the above requirements for this kind of the base plate.
It is another object of the invention to provide a steel column base plate member, which has a novel configuration to avoid any stress concentration to perform a smooth stress transmission from a column member to a foundation and to make it possible to perform a combination of J-shaped groove welding between both flanges of column and base plate and fillet welding between both webs of column and base plate adapted to meet stresses acting upon the base plate.
It is further object of the present invention is to provide a novel base plate member, which is formed by casting or forging in a unitary body with grooves formed on the top surface of projections for effecting the J-shaped groove welding and has a configuration in agreement with a stress distribution acting thereupon and adapted not to be subjected to a detrimental effect of welding heating with the surface in contact with the foundation.
It is still more object of the invention to provide a base plate member for connecting an H-shaped steel column member to a concrete foundation, which is inexpensive of manufacture and serves to decrease the total cost of a construction.
In one aspect, the invention provides a base plate member for connecting an H-shaped steel column member to a concrete foundation, which base plate member is a unitary body comprising a substantially planar bottom plate portion engageable with said concrete foundation, a projection upwardly extending from the planar bottom plate portion and having a top surface whose shape is substantially identical to cross sectional shape of the steel column member, a web part of a top surface of said projection in opposition to a web of said column member havin a width broader than that of said web of the column member so as to effect sufficient fillet welding therewith, J-shaped welding grooves formed along both edges of said top surface of said projection facing to lower ends of flanges of said column member extending from outer peripheries of the top surface of said projection so as to effect J-shaped groove welding between said lower ends of the flanges and the J-shaped welding grooves, a sloped top surface formed between said projection to said bottom plate portion so as to increase the thickness thereof as the planar bottom plate portion extends toward said projection, and abutments formed on the planar bottom portion in a sufficient thickness and having anchor bolt holes bored therethrough.
In another aspect, the invention provides a method of connecting an H-shaped steel column member to a base plate member, wherein said base plate member comprises a substantially planar bottom plate portion, a projection extending from the planar bottom plate portion and having a top surface whose shape is substantially identical to cross sectional shape of the steel column member, a web part of a top surface of said projection having a width broader than that of a web column member, J-shaped welding grooves formed along both edges of said top surface of said projection facing to lower ends of flanges of said column member, the improvement characterized by, the steps of placing the lower end surface of said column member onto said top surface of said base plate member in a desired relation, effecting fillet welding along between lower ends of said web of the column member and said top surface of said base plate member, and effecting J-shaped groove welding along said J-shaped grooves of said base plate member between bottom surfaces of said flanges of the column member and said grooved surfaces of said base plate member.
BRIEF DESCRIPTION OF THE DRAWING
For a better understanding of the invention, reference is made to the accompanying drawing, in which:
FIG. 1 is an elevation of a steel column base plate member for supporting an H-shaped column member, according to the invention;
FIG. 2 is a plan view of the base plate member of FIG. 1;
FIGS. 3 and 4 are schematic partial sectional views, illustrating the manner in which an H-shaped column member is welded to the base plate member of the invention;
FIG. 5 is a schematic sectional view showing J-shaped groove and fillet welded beads for connecting the column member to the base plate member according to the invention;
FIG. 6 is a perspective view illustrating a modified base plate of the invention formed with bosses for facilitating the registration of the column member with the base plate member;
FIG. 7 is a perspective view of the base plate member according to the invention explanatorily illustrating the configuration of the base plate member;
FIG. 8 is a diagrammatical view showing an axial force, a bending moment and a shearing force acting upon an H-shaped column member and a relationship between these forces and flanges and a web of the column member;
FIG. 9 illustrates various reaction distributions depending upon the relation between bending moments and compressive forces; and
FIG. 10a and 10b are schematic sectional views of J-shaped groove weld and L-shaped groove weld, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, a steel column base plate member 20 according to the present invention is to join an H-shaped steel column member 1 to a concrete foundation 2. The base plate member 20 itself is secured to the concrete foundation 2 by anchor bolts 17 and nuts 17a.
The base plate member 20 has a planar bottom plate portion 6 whose bottom surface area is large enough to distribute the load of the steel column member 1 to the concrete foundation 2 at a stress which is below an allowable limit to the concrete member of the foundation 2 through the interface between the base plate member and the concrete foundation. A projection 7 is integrally formed with the planar bottom portion 6 so as to form a top surface 7a and 7b whose shape is substantially identical to the cross section of the H-shaped steel column member 1, said top surface of web 7b of projection having a broader width than that of web 1b of the steel column member 1, and a J-shaped groove 5 formed along the edges of top surface 7a of projection, the width of which groove 5 is substantially identical to the bottom surface of flange of the steel column member so as to effect groove welding between the grooved surface of projection and the bottom surface of the flange of steel column member, and a residual top surface 7a of projection extending inwardly toward web from the edge thereof, so as to effect the fillet welding between said top surface 7a of base plate and the lower end of flanges of column member 1.
Referring to FIG. 1, the height H of the projection 7 is determined on the basis of the ease of welding the column member 1 to the top surface 7a and 7b and the suppression of the welding strain or bending of the base plate member 20 due to the welding of the column member 1 thereto.
Smoothly curved surface portions 8 are formed where the projection 7 rises from the planar portion 6, so as to eliminate any stress concentration in the base plate member 20 due to the presence of sharp corners. Thus, the radius of curvature of the curved surface 8 must be chosen on the basis of effective suppression of the stress concentration. Whereby, the smooth transfer of the load of the column member 1 toward the concrete foundation 2 is ensured.
The planar portion 6 has a sloped or tapered top surface 6a, so that the thickness of the planar portion 6 increases as it extends toward the projection 7. With such sloped top surface 6a, the thickness of the planar portion 6 is increased at those parts where the stress is high, while allowing comparatively thin thickness to the less stressed parts thereof. As a result, the rigidity of the projection 7 is enhanced, too. Furthermore, superfluous thickness of the base plate 20 is eliminated.
Abutments 9 are integrally formed at the parts where anchor bolt holes 11 are bored through the base plate member 20. The top surface of the abutment 9 is made parallel to the bottom plane of the planar portion 6, so as to stabilize the contact surface between the nut 17a and the abutment 9. It is, of course, possible to insert suitable washers (not shown) between the abutment and the nuts 17a. Referring to FIGS. 1 and 2, the width and the thickness d of the abutment 9 are so chosen as to ensure smooth transfer of the load of the column member 1 toward the anchor bolts 17. Suitably curved surfaces 10 are formed at the junction between the abutment 9 and the projection 7, for preventing stress concentration thereat.
The steel column base plate member 20 of the aforesaid construction may be made by casting or by forging.
The steel column member, e.g., the H-shaped steel member, is made by rolling in a universal mill. Accordingly, once its nominal dimension is determined, the inside dimensions and the radii of curvature of the junctions of different inside surface portions are fixed, regardless of the difference in the thickness of flanges and webs thereof. In fact, the shapes and dimensions of the steel column members to be used in architectural buildings and construction structures are selected from a limited number of varieties. Accordingly, it is comparatively easy to provide such top surface 7a and 7b of the projection 7 which is of substantially identical shape with the sectional shape of the steel column member 1.
According to the present invention, the web part 7b of the top surface of the projection facing the lower ends of the web of the column member 1 has a width broader than that of the web so as to effect a fillet welding between the web part 7b of the top surface of the projection and the lower end of the web along both sides thereof.
The J-shaped groove 5 is formed along the edges of top surface 7a of projection, the width of which groove 5 is substantially identical to or broader than the bottom surface of the flange of the steel column member so as to effect groove welding between the J-shaped grooved surface of projection and the bottom surface of the flange of steel column member and the residual top surface 7a of projection extending inwardly toward web from the edge of groove so as to effect the fillet welding between said top surface 7a of base plate and the inner lower end of flange of column member 1. The J-shaped welding grooves 5 are formed at the time of casting or forging of the base plate member 20 per se.
The base plate member may be preferably formed with a center line or center lines (not shown) at the time of casting or forging corresponding to scores marked in the column member by a scraper and lines marked in the concrete foundation for facilitating the correct registering of the base plate member 20 relative to the column member and the concrete foundation.
To facilitate the correct registering of the steel column member 1 relative to the base plate member 20, suitable bosses 12 may be provided at the top surface 7a and 7b of the projection as shown in FIG. 6.
In actual construction, fillet welding is performed along the top surface 7b on both sides of the web of the column member to form fillet welding beads 13 as shown in FIGS. 3 and 5 and J-shaped groove welding or butt welding is performed along the J-shaped grooves 5 with the flanges of the H-shaped column member 1 to form groove welding beads 14 as shown in FIGS. 4 and 5. Before the J-shaped groove welding, the fillet welding may be effected successively along the inner lower end of the flanges and the top surface 7a to form fillet welding beads 15 as shown in FIGS. 4 and 5 which serve to increase strength of the welded portions and as sealing beads for the subsequent J-shaped groove welding. It is apparent to those skilled in the art that the use of bosses 12, as shown in FIG. 6, will facilitate the registration or indexing of the column member 1 with the base plate member 20.
In using the base plate member 20 according to the present invention for a construction, the top surface 7a and 7b of projection of base plate is brought into contact with the lower end of an H-shaped column member 1 with the aid of the center lines of the plate member in registry with the scores of the column member. Tack welding is effected at several locations between the column member and the base plate member, for example, two points at the web of the column member and four points at the inner lower end of the flanges of the column member for fixing a relative position therebetween to facilitate the subsequent welding. Then fillet welding is performed along on both sides of the web of the column member to form the bead 13. Fillet welding is preferably effected successively along the inner lower ends of the flanges of the column member to form beads 15 which serve to provide an additional reinforcement for the flange portion and prevent the J-shaped groove weld bead 14 from dropping over. The beads 15 serve additionally to minimize of shrinkage of the member after the prosecution of welding in conjunction with the metallic touch of the top surface of the base plate member with the lower end of the column. The beads 15 often extend through a clearance between the flange and the top surface 7a into a space of the J-grooves. Such an excess bead extending into the groove 5 is then gouged or removed. Then, J-shaped groove welding or butt welding is effected to form beads 14 between the flanges of the column member and the protrusion 7.
The column member and the base plate member thus united are brought onto a concrete foundation such that anchor bolts 17 extending from the foundation pass through the anchor bolt holes 11 and the center lines of the base plate member are in registry with the lines marked in the concrete foundation. The nuts 17a are threadedly engaged with the anchor bolts 17 and then tightened with a determined amount of torque by means of a suitable equipment such as a constant torque wrench.
The base plate member for the H-shaped column member according to the present invention has following characteristics distinguishable over those in the prior art.
(1) Outer configuration:
The base plate member according to the present invention has the configuration as shown in FIGS. 1, 2 and 7. There are smoothly curved surface portions 8 at the junctions between the projection 7 and the sloped top surface 6a and further smoothly curved surface portions at the junctions 10 between the abutments 9 and the planar bottom portion 6. These smooth surfaces prevent any stress concentration and serve to transmit smoothly the load from the column member to the concrete foundation.
The area shown in chain lines 22 in FIG. 7 illustrates the contact surface in contact with the bottom of the column member which provides a metal contact which serves to keep an accuracy of the height of the column member and makes it easy to set the column member on the concrete foundation.
The J-shaped grooves for butt welding are integrally formed in the base plate in casting or forging so that the forming of the J-shaped grooves scarcely increases the cost of the base plate and the column member is not required to have any worked portion for butt welding. Accordingly, the working of column members will be simplified to save time and cost for manufacturing the construction.
(2) The combination of fillet and butt weldings:
It has been known that shearing strengths of fillet and butt welded portions at their throats are substantially equal to each other, while the tensile strength of the butt welded portion is generally higher than that of the fillet welded portion. The present invention utilizes these characteristics in strength to enable the base plate to support a load in the most effective manner.
In general, a column is simultaneously subjected to an axial force N, a bending moment M and a shearing force Q as shown in FIG. 8 which diagrammatically shows the axial force, the bending moment and the shearing force acting upon the column member. An H-shaped column member is generally so arranged that the flanges of the column member will receive the bending moment M and the web will receive the shearing force Q. Accordingly, the welded portions of the flanges will be subjected to tensile forces and the welded portions of the web will be subjected to a shearing force. By welding the flange by the butt welding and the web by the fillet welding the most effective welding arrangement can be accomplished which beneficially meets stresses derived from the forces and moments to which the column member is subjected. The base plate member according to the present invention has a configuration suitable to carry out the above the combination of fillet and butt weldings. In more detail, the base plate member comprises the H-shaped top surface 7a and 7b whose shape is substantially identical to cross sectional shape of the steel column member, a top surface 7b of projection in opposition to the web of the column member having a broader width than that of web of column member sufficient to effect fillet welding between the web of the column member and the top surface 7b, and J-shaped welding grooves 5 formed along the edges of the top surfaces 7a in opposition to the flanges of the column member for J-groove welding with it.
The fillet welding at the web may be effected in succession along the inner lower end of the flanges and the top surface 7a to form the fillet welding beads 15 which serve to prevent the J-shaped groove weld from droppings during the course of welding and provide an additional reinforcement for the web portion.
(3) Dynamics on the base plate:
The column member is subjected to the axial force N, the bending moment M and the shearing force Q which act between the base plate and the concrete foundation as shown in FIG. 8. Depending upon the magnitude of these forces and their combination, a reaction force between the base plate and the foundation varies in distribution and amount as shown in FIG. 9. FIG. 9A shows the reaction force in case of the bending moment is relatively small in comparison with the compressive force, FIG. 9B is in case of the bending moment is normal or intermediate and FIG. 9C is in case of the moment is a great value. In any case, these compressive force, bending moment and shearing force simultaneously act upon the column member, so that reaction forces are caused between the base plate member and the column member as shown in arrows in FIG. 9 wherein solid lines of the arrows show theoretical distribution of the reactions and dot-and-dash lines show actual distributions. In case of FIG. 9C, due to the great moment, one flange of the column member tends to raise to cause a great tensile force in anchor bolts.
When the base plate member is subjected to a great contact force in an axial direction of the column member which causes a bending action (a positive bending moment) on the plate member, so that the plate member is required to have sufficient yield strength and rigidity to resist to the bending action.
When the anchor bolts are subjected to a great tensile force as shown in FIG. 9C, a great reaction force is caused in the proximity of the holes for the bolts formed in the base plate and results in a bending action (a negative bending moment) on the plate member, so that the member is required to have sufficient yield strength and rigidity to resist to the action.
The bending moment and the shearing force generally act on the base plate member as alternate stresses. Accordingly, the base plate member is generally required to have a symmetrical yield strength and rigidity. The yield strength will resist to the stress so as not to be broken and the rigidity will resist to the stress so as to restrain a deformation.
At any rate, when the base plate member is subjected to reaction forces as shown in FIGS. 9A, 9B and 9C, the base plate will be subjected to a bending action of which bending stress is maximum at the place on the base plate member in opposition to the flanges and web of the column member.
Accordingly, the feature of the projection 7 of the base plate projecting from the base portion and corresponding to the sectional area of the column member and the feature of decreasing the thickness of the bottom plate portion toward the outer ends thereof provided a rational configuration in agreement with the stress distribution. In addition, with the configuration the top surface of the projection to be welded to the lower end of the column member is remote from the base portion of the base plate member so as to be remote from the portions subjected to violent heating for welding, thereby preventing the base portion from deforming in welding. The base plate member having a changing thickness can be advantageously made by casting or forging.
(4) Advantages of J-shaped groove welding:
An amount of weld metal or deposited metal in the J-shaped welding is less than those in any other welding methods for the same purpose. The reliability in penetration or weld penetration in the proximity of the root of J-shaped groove weld is higher than those in any other methods and also higher than that in L-shaped groove weld as shown in FIG. 10b. The J-shaped groove welding operation can be carried out with ease. In spite of these advantages, the J-shaped groove welding requires to form J-shaped grooves which are apt to increase the cost of welding. According to the invention by casting and forging the base plate member, J-shaped grooves can easily be formed in the base plate member, so that the base plate member can utilize the advantages of the J-shaped groove welding without increasing cost for providing the J-shaped grooves.
(5) Cost comparison:
We compared the cost of the cast steel base plate members according to the invention with that of the prior art steel base plates for H-shaped column members 450 (web) × 300 (flange) mm. One example of the comparison is indicated in Table I.
Table I__________________________________________________________________________ Cast steel base plate Steel base plate (Present invention) (Prior art) Total Total Total Total Unit price weight cost weight cost__________________________________________________________________________Casting $0.605/lb (Υ400/kg) 430 lbs $260 0 0 (195 kgs) (Υ78,000) 1,043 lbs $158MaterialSteel plate $0.151/lb (Υ100/kg) 0 0 (473 kgs) (Υ47,300)cost 132 lbs $56Welding rod $0.423/lb (Υ280/kg) 0 0 (60 kgs) (Υ16,800) 430 lbs $260 1,175 lbs $214Total (195 kgs) (Υ78,000) (533 kgs) (Υ64,100)WorkingLabor cost $33.3/man (Υ10,000/man)cost Indirect 0 0 3.97 men $199cost $16.7/man (Υ5,000/man) (Υ59,595)Total $260 (Υ78,000) $412.3 (Υ123,695)Economical Comparison 63% 100%__________________________________________________________________________
A number of cast steel base plates of totally 430 lbs according to the invention were used in the comparison, which only require casting operation but not require any other operation such as working or welding operation for providing the base plates themselves. Accordingly, the total cost was $260. In contrast herewith the steel base plates of the prior art require the steel plates of 1,043 lbs and welding rods of 132 lbs for providing the number of the base plates equal to the above cast steel plates and further require the working operation with direct and indirect costs, so that the total cost was $412.3. The cost of the cast steel base plate according to the invention is only 63% of that of the welded steel base plate of the prior art.
As can be seen from the above description, the base plate member according to the invention has a various of novel features of the configuration making it possible to effect a combination of fillet and butt welding to meet the stress condition acting upon the column member and the base plate; preventing the base portion from deforming in welding by arranging the welding portion on the top of the protrusion remote from the base portion; having an effective sectional shape to meet the bending stress distribution; and making it possible to effect the effective J-shaped groove welding.
It is understood by those skilled in the art that the foregoing description is a preferred embodiment of the disclosed base plate and that various changes and modifications may be made in the invention without departing from the spirit and scope thereof. | A steel column base member for connecting an H-shaped structural steel column member to a concrete foundation, which base plate member is an integral cast or forged body comprising a bottom plate member to engage the foundation, an H-shaped projection upwardly extending from the bottom plate member and having J-shaped grooves formed along both edges of top surface of projection the width of web of projection being broader than that of web of column member, so as to effect groove welding between the bottom surface of the steel column member and the J-shaped grooved surfaces, and fillet welding both side of web of the column member and base plate member. A method of connecting an H-shaped steel column member to a base plate member is characterized by, effecting fillet welding along between lower ends of a web of column member and a top surface of base plate member, effecting J-shaped groove welding along betweeen J-shaped groove surfaces of base plate member and the bottom surfaces of flanges of steel column member, and fillet welding along between the inner lower ends of flanges of a steel column member and the top surfaces of flanges of projection. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No. 09/864,737, filed May 23, 2001, now U.S. Pat. No. 6,459,105, issued Oct. 1, 2002, which is a continuation of application Ser. No. 09/567,262, filed May 9, 2000, now U.S. Pat. No. 6,255,196, issued Jul. 3, 2001, which is a divisional of application Ser. No. 09/434,147, filed Nov. 4, 1999, now U.S. Pat. No. 6,196,096, issued Mar. 6, 2001, which is a continuation of application Ser. No. 09/270,539, filed Mar. 17, 1999, now U.S. Pat. No. 6,155,247, issued Dec. 5, 2000, which is a divisional of application Ser. No. 09/069,561, filed Apr. 29, 1998, now U.S. Pat. No. 6,119,675, issued Sep. 19, 2000, which is a divisional of application Ser. No. 08/747,299, filed Nov. 12, 1996, now U.S. Pat. No. 6,250,192, issued Jun. 26, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to a method and apparatus for sawing semiconductor substrates such as wafers and, more specifically, to a wafer saw and method of using the same employing multiple indexing techniques and multiple blades for more efficient sawing and for sawing multiple die sizes and shapes from a single semiconductor wafer.
[0004] 2. State of the Art
[0005] An individual integrated circuit or chip is usually formed from a larger structure known as a semiconductor wafer, which is usually comprised primarily of silicon, although other materials such as gallium arsenide and indium phosphide are also sometimes used. Each semiconductor wafer has a plurality of integrated circuits arranged in rows and columns with the periphery of each integrated circuit being rectangular. Typically, the wafer is sawn or “diced” into rectangularly shaped discrete integrated circuits along two mutually perpendicular sets of parallel lines or streets lying between each of the rows and columns thereof. Hence, the separated or singulated integrated circuits are commonly referred to as dice.
[0006] One exemplary wafer saw includes a rotating dicing blade mounted to an aluminum hub and attached to a rotating spindle, the spindle being connected to a motor. Cutting action of the blade may be effected by diamond particles bonded thereto, or a traditional “toothed” type blade may be employed. Many rotating wafer saw blade structures are known in the art. The present invention is applicable to any saw blade construction, so further structures will not be described herein.
[0007] Because semiconductor wafers in the art usually contain a plurality of substantially identical integrated circuits arranged in rows and columns, two sets of mutually parallel streets extending perpendicular to each other over substantially the entire surface of the wafer are formed between each discrete integrated circuit and are sized to allow passage of a wafer saw blade between adjacent integrated circuits without affecting any of their internal circuitry. A typical wafer sawing operation includes attaching the semiconductor wafer to a wafer saw carrier, mechanically, adhesively or otherwise as known in the art, and mounting the wafer saw carrier on the table of the wafer saw. A blade of the wafer saw is passed through the surface of the semiconductor wafer, either by moving the blade relative to the wafer, the table of the saw and the wafer relative to a stationary blade, or a combination of both. To dice the wafer, the blade cuts precisely along each street, returning back over (but not in contact with) the wafer while the wafer is laterally indexed to the next cutting location. Once all cuts associated with mutually parallel streets having one orientation are complete, either the blade is rotated 90° relative to the wafer or the wafer is rotated 90°, and cuts are made through streets in a direction perpendicular to the initial direction of cut. Since each integrated circuit on a conventional wafer has the same size and rectangular configuration, each pass of the wafer saw blade is incrementally indexed one unit (a unit being equal to the distance from one street to the next) in a particular orientation of the wafer. As such, the wafer saw and the software controlling it are designed to provide uniform and precise indexing in fixed increments across the surface of a wafer.
[0008] It may, however, be desirable to design and fabricate a semiconductor wafer having various integrated circuits and other semiconductor devices thereon, each of which may be of a different size. For example, in radio-frequency ID (RFID) applications, a battery, chip and antenna could be incorporated into the same wafer such that all semiconductor devices of an RFID electronic device are fabricated from a single semiconductor wafer. Alternatively, memory dice of different capacities, for example, 4, 16 and 64 megabyte DRAMs, might be fabricated on a single wafer to maximize the use of silicon “real estate” and reduce thiefage or waste of material near the periphery of the almost-circular (but for the flat) wafer. Such semiconductor wafers, in order to be diced, however, would require modifications to and/or replacement of existing wafer saw hardware and software.
SUMMARY OF THE INVENTION
[0009] Accordingly, an apparatus and method for sawing semiconductor wafers, including wafers having a plurality of semiconductor devices of different sizes and/or shapes therein, is provided. In particular, the present invention provides a wafer saw and method of using the same capable of “multiple indexing” of a wafer saw blade or blades to provide the desired cutting capabilities. As used herein, the term “multiple indexing” contemplates and encompasses both the lateral indexing of a saw blade at multiples of a fixed interval and at varying intervals which may not comprise exact multiples of one another. Thus, for conventional wafer configurations containing a number of equally sized integrated circuits, the wafer saw and method herein can substantially simultaneously saw the wafers with multiple blades and therefore cut more quickly than single blade wafer saws known in the art. Moreover, for wafers having a plurality of differently-sized or shaped integrated circuits, the apparatus and method herein provides a multiple indexing capability to cut non-uniform dice from the same wafer.
[0010] In a preferred embodiment, a single-blade, multi-indexing saw is provided for cutting a wafer containing variously configured integrated circuits. By providing multiple-indexing capabilities, the wafer saw can sever the wafer into differently sized dice corresponding to the configuration of the integrated circuits contained thereon.
[0011] In another preferred embodiment, a wafer saw is provided having at least two wafer saw blades spaced a lateral distance from one another and having their centers of rotation in substantial parallel mutual alignment. The blades are preferably spaced apart a distance equal to the distance between adjacent streets on the wafer in question. With such a saw configuration, multiple parallel cuts through the wafer can be made substantially simultaneously, thus essentially increasing the speed of cutting a wafer by the number of blades utilized in tandem. Because of the small size of the individual integrated circuits and the correspondingly small distances between adjacent streets on the wafer, it may be desirable to space the blades of the wafer saw more than one street apart. For example, if the blades of a two-blade saw are spaced two streets apart, a first pass of the blades would cut the first and third laterally separated streets. A second pass of the blades through the wafer would cut through the second and fourth streets. The blades would then be indexed to cut through the fifth and seventh streets, then sixth and eighth, and so on.
[0012] In another preferred embodiment, at least one blade of a multi-blade saw is independently raisable relative to the other blade or blades when only a single cut is desired on a particular pass of the carriage. Such a saw configuration has special utility where the blades are spaced close enough to cut in parallel on either side of larger integrated circuits, but use single blade capability for dicing any smaller integrated circuits. For example, a first pass of the blades of a two blade saw could cut a first set of adjacent streets defining a column of larger integrated circuits of the wafer. One blade could then be independently raised or elevated to effect a subsequent pass of the remaining blade cutting along a street that may be too laterally close to an adjacent street to allow both blades to cut simultaneously, or that merely defines a single column of narrower dice. This feature would also permit parallel scribing of the surface of the wafer to mutually isolate conductors from, for example, tie bars or other common links required during fabrication, with subsequent passage by a single blade indexed to track between the scribe lines to completely sever or singulate the adjacent portions of the wafer.
[0013] In yet another preferred embodiment, at least one blade of a multi-blade saw is independently laterally translatable relative to the other blade or blades. Thus, in a two-blade saw, for example, the blades could be laterally adjusted between consecutive saw passes of the sawing operation to accommodate different widths between streets. It should be noted that this preferred embodiment could be combined with other embodiments herein to provide a wafer saw that has blades that are both laterally translatable and independently raisable, or one translatable and one raisable, as desired.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] [0014]FIG. 1 is a schematic side view of a first preferred embodiment of a wafer saw in accordance with the present invention;
[0015] [0015]FIG. 2 is a schematic front view of the wafer saw illustrated in FIG. 1;
[0016] [0016]FIG. 3 is a schematic front view of a second embodiment of a wafer saw in accordance with the present invention;
[0017] [0017]FIG. 4 is a schematic view of a first silicon semiconductor wafer having a conventional configuration to be diced with the wafer saw of the present invention;
[0018] [0018]FIG. 5 is a schematic view of a second silicon semiconductor wafer having variously sized semiconductor devices therein to be diced with the wafer saw of the present invention;
[0019] [0019]FIG. 6 is a schematic front view of a third embodiment of a wafer saw in accordance with the present invention;
[0020] [0020]FIG. 7 is a schematic view of a third silicon semiconductor wafer having variously sized semiconductor devices therein to be diced with the wafer saw of the present invention;
[0021] [0021]FIG. 8 is a top elevation of a portion of a semiconductor substrate bearing conductive traces connected by tie bars; and
[0022] [0022]FIG. 9 is a top elevation of a portion of a semiconductor substrate bearing three different types of components formed thereon.
DETAILED DESCRIPTION OF THE INVENTION
[0023] As illustrated in FIGS. 1 and 2, an exemplary wafer saw 10 according to the invention is comprised of a base 12 to which extension arms 14 and 15 suspended by support 16 are attached. A wafer saw blade 18 is attached to a spindle or hub 20 which is rotatably attached to the extension arm 15 . The blade 18 may be secured to the hub 20 and extension arm 15 by a threaded nut 21 or other means of attachment known in the art. The wafer saw 10 also includes a translatable wafer table 22 movably attached in both X and Y directions (as indicated by arrows in FIGS. 1 and 2) to the base 12 . Alternatively, blade 18 may be translatable relative to the table 22 to achieve the same relative X-Y movement of the blade 18 to the table 22 . A silicon wafer 24 to be scribed or sawed may be securely mounted to the table 22 . As used herein, the term “saw” includes scribing of a wafer, the resulting scribe line 26 not completely extending through the wafer substrate. Further, the term “wafer” includes traditional full semiconductor wafers of silicon, gallium arsenide, or indium phosphide and other semiconductor materials, partial wafers, and equivalent structures known in the art wherein a semiconductor material table or substrate is present. For example, so-called silicon-on-insulator or “SOI” structures, wherein silicon is carried on a glass, ceramic or sapphire (“SOS”) base, or other such structures as known in the art, are encompassed by the term “wafer” as used herein. Likewise, “semiconductor substrate” may be used to identify wafers and other structures to be singulated into smaller elements.
[0024] The saw 10 is capable of lateral multi-indexing of the table 22 or blade 18 or, in other words, translatable from side-to-side in FIG. 2 and into and out of the plane of the page in FIG. 1 various non-uniform distances. As noted before, such non-uniform distances may be mere multiples of a unit distance, or may comprise unrelated varying distances, as desired. Accordingly, a wafer 24 having variously sized integrated circuits or other electronic devices, elements, or components therein may be sectioned or diced into its non-uniformly sized components by the multi-indexing wafer saw 10 . In addition, as previously alluded, the saw 10 may be used to create scribe lines or cuts that do not extend through the wafer 24 . The wafer 24 can then subsequently be diced by other methods known in the art or sawed completely through after the blade 18 has been lowered to traverse the wafer to its full depth or thickness.
[0025] Before proceeding further, it will be understood and appreciated that design and fabrication of a wafer saw according to the invention having the previously-referenced, multi-indexing capabilities, independent lateral blade translation and independent blade raising or elevation is within the ability of one of ordinary skill in the art and, that likewise, the control of such a device to effect the multiple-indexing (whether in units of fixed increments or otherwise), lateral blade translation and blade elevation may be effected by suitable programming of the software-controlled operating system, as known in the art. Accordingly, no further description of hardware components or of a control system to effectuate operation of the apparatus of the invention is necessary.
[0026] Referring now to FIG. 3, another illustrated embodiment of a wafer saw 30 is shown having two laterally-spaced blades 32 and 34 with their centers of rotation in substantial parallel alignment transverse to the planes of the blades. For a conventional, substantially circular silicon semiconductor wafer 40 (flat omitted), as illustrated in FIG. 4, having a plurality of similarly configured integrated circuits 42 arranged in evenly spaced rows and columns, the blades can be spaced a distance D substantially equal to the distance between adjacent streets 44 defining the space between each integrated circuit 42 . In addition, if the streets 44 of wafer 40 are too closely spaced for side-by-side blades 32 and 34 to cut along adjacent streets, the blades 32 and 34 can be spaced a distance D substantially equal to the distance between two or more streets. For example, a first pass of the blades 32 and 34 could cut along streets 44 a and 44 c and a second pass along streets 44 b and 44 d . The blades could then be indexed to cut the next series of streets and the process repeated for streets 44 e , 44 f , 44 g , and 44 h . If, however, the integrated circuits of a wafer 52 have various sizes, such as integrated circuits 50 and 51 as illustrated in FIG. 5, at least one blade 34 is laterally translatable relative to the other blade 32 to cut along the streets, such as street 56 , separating the variously sized integrated circuits 50 . The blade 34 may be variously translatable by a stepper motor 36 having a lead screw 38 or by other devices known in the art, such as high precision gearing in combination with an electric motor or hydraulics, or other suitable mechanical drive and control assemblies. For a wafer 52 , the integrated circuits, such as integrated circuits 50 and 51 , may be diced by setting the blades 32 and 34 to simultaneously cut along streets 56 and 57 , indexing the blades, setting them to a wider lateral spread and cutting along streets 58 and 59 , indexing the blades while monitoring the same lateral spread or separation and cutting along streets 60 and 61 , and then narrowing the blade spacing and indexing the blades and cutting along streets 62 and 63 . The wafer 52 could then be rotated 90°, as illustrated by the arrow in FIG. 5, and the blade separation and indexing process repeated for streets 64 and 65 , streets 66 and 67 , and streets 68 and 69 .
[0027] As illustrated in FIG. 6, a wafer saw 70 according to the present invention is shown having two blades 72 and 74 , one of which is independently raisable (as indicated by an arrow) relative to the other. As used herein, the term “raisable” includes vertical translation either up or down. Such a configuration may be beneficial for situations where the distance between adjacent streets is less than the minimum lateral achievable distance between blades 72 and 74 , or only a single column of narrow dice is to be cut, such as at the edge of a wafer. Thus, when cutting a wafer 80 , as better illustrated in FIG. 7, the two blades 72 and 74 can make a first pass along streets 82 and 83 . One blade 72 can then be raised, the wafer 80 indexed relative to the unraised blade 74 and a second pass performed along street 84 only. Blade 72 can then be lowered and the wafer 80 indexed for cutting along streets 85 and 86 . The process can be repeated for streets 87 (single-blade pass), 88 , and 89 (double-blade pass). The elevation mechanism 76 for blade 72 may comprise a stepper motor, a precision-geared hydraulic or electric mechanism, a pivotable arm which is electrically, hydraulically or pneumatically powered, or other means well known in the art.
[0028] Finally, it may be desirable to combine the lateral translation feature of the embodiment of the wafer saw 30 illustrated in FIG. 3 with the independent blade raising feature of the wafer saw 70 of FIG. 6. Such a wafer saw could use a single blade to cut along streets that are too closely spaced for dual-blade cutting or in other suitable situations, and use both blades to cut along variously spaced streets where the lateral distance between adjacent streets is sufficient for both blades to be engaged.
[0029] It will be appreciated by those skilled in the art that the embodiments herein described while illustrating certain embodiments are not intended to so limit the invention or the scope of the appended claims. More specifically, this invention, while being described with reference to semiconductor wafers containing integrated circuits or other semiconductor devices, has equal utility to any type of substrate to be scribed or singulated. For example, fabrication of test inserts or chip carriers formed from a silicon (or other semiconductor) wafer and used to make temporary or permanent chip-to-wafer, chip-to-chip and chip-to-carrier interconnections and that are cut into individual or groups of inserts, as described in U.S. Pat. Nos. 5,326,428 and 4,937,653, may benefit from the multi-indexing method and apparatus described herein.
[0030] For example, illustrated in FIG. 8, a semiconductor substrate 100 may have traces 102 formed thereon by electrodeposition techniques requiring connection of a plurality of traces 102 through a tie bar 104 . A two-blade saw in accordance with the present invention may be employed to simultaneously scribe substrate 100 along parallel lines 106 and 108 flanking a street 110 in order to sever tie bars 104 of adjacent substrate segments 112 from their associated traces 102 . Following such severance, the two columns of adjacent substrate segments 112 (corresponding to what would be termed “dice” if integrated circuits were formed thereon) are completely severed along street 110 after the two-blade saw is indexed for alignment of one blade therewith, and the other blade raised out of contact with substrate 100 . Subsequently, when either the saw or the substrate carrier is rotated 90°, singulation of the segments 112 is completed along mutually parallel streets 114 . Thus, substrate segments 112 for test or packaging purposes may be fabricated more efficiently in the same manner as dice and in the same sizes and shapes.
[0031] Further, and as previously noted, RFID modules may be more easily fabricated nents of a module are formed on a single wafer and retrieved therefrom for carrier substrate providing mechanical support and electrical interconnection ents.
[0032] As shown in FIG. 9, a portion of a substrate 200 is depicted with three adjacent ying-width segments, the three widths of segments illustrating batteries 202 , ntennas 206 of an RFID device. With all of the RFID components formed on a 200 , an RFID module may be assembled by a single pick-and-place apparatus at ation. Thus, complete modules may be assembled without transfer of partially-les from one station to the next to add components. Of course, this approach ed to any module assembly wherein all of the components are capable of being single semiconductor substrate. Fabrication of different components by device fabrication techniques known in the art is within the ability of those of the art and, therefore, no detailed explanation of the fabrication process leading of different components on a common wafer or other substrate is necessary. iconductor device elements not involved in a particular process step is widely o similar isolation of entire components is also easily effected to protect the omponent until the next process step with which it is involved. | A semiconductor wafer saw and method of using the same for dicing semiconductor wafers comprising a wafer saw including variable lateral indexing capabilities and multiple blades. The wafer saw, because of its variable indexing capabilities, can dice wafers having a plurality of differently sized semiconductor devices thereon into their respective discrete components. In addition, the wafer saw with its multiple blades, some of which may be independently laterally or vertically movable relative to other blades, can more efficiently dice silicon wafers into individual semiconductor devices. |
FIELD OF THE INVENTION
The invention generally relates to annotating recorded data, and more particularly to automatically annotating audio and/or visual data recordings based at least in part on a timing indicator.
BACKGROUND
Recent advances in recording, storage and form factor technology have resulted in proliferation of personal data and media recording devices, such as personal video cameras, photo cameras, audio recorders, etc. However, incident to such proliferation is tracking problem inherent to cross-referencing recordings with the environment in which the recording was taken. This problem is especially applicable to storage media having large storage capacity, e.g., capacity to store thousands of images, many hours of video recordings, tens of thousands of music recordings, etc., it becomes a near insurmountable problem to accurately and consistently annotate recorded data with information to identify the context for the recorded data.
It is increasingly difficult to simply label storage devices with all of the data content therein, as historically has been done, e.g., labeling a tape cassette or a video cassette recorder cartridge. And, with the ability to easily replace some or all of a storage device's content, even with an ability to label the storage device, such labeling may quickly become stale.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the present invention will become apparent from the following detailed description of the present invention in which:
FIG. 1 illustrates an exemplary system incorporating the invention.
FIG. 2 is a flowchart according to one embodiment of the invention for recording an event and providing the recording to other event attendees.
FIG. 3 is a flowchart for a variation of the FIG. 2 embodiment.
FIG. 4 illustrates a suitable computing environment in which certain aspects of the invention may be implemented.
DETAILED DESCRIPTION
FIG. 1 illustrates an exemplary system incorporating the invention. Illustrated are an audio and/or visual transceiver 100 , such as a cellular telephone configured to transmit audio and/or visual data, a digital camera 102 , a video camera 104 , an audio recorder 106 . It will be appreciated by one skilled in the art that the illustrated devices 100 - 104 are exemplary devices, and that other devices may be utilized.
Associated with each of these devices are timers 108 , 110 , 112 , 114 . The timers may be integral to the devices 100 - 104 as illustrated, or they may represent timing functionality or circuitry that receives timing data from an external source. For example, the digital camera 102 may have a receiver capable of receiving timing data originating from an external source, such as the United States Naval Observatory's Master Clock (USNO), the Time and Frequency Division of the National Institute of Standards and Technology (NIST), or another clock source. To allow coordination of activity between devices 100 - 104 , devices 100 - 104 may be configured to use the same timing source. In one embodiment, calendar date values may be determined from timing values. For example, a timing value may represent the number of seconds since a particular date.
Also illustrated are machines 116 , 118 , and 120 , which may be personal computers, personal digital assistants, or other machines. Each of the machines 116 - 120 are configured to operate a calendar application 122 , 124 , 126 (or other application associating events and times), and a data transfer application 128 , 130 , 132 such as electronic mail (E-mail) program, instant messaging system or other data transfer ability. The audio and/or visual transceiver, digital camera, video camera and audio recorder are assumed to have a wired and/or wireless communication link 134 to some or all of the machines 116 , 118 , and 120 , by way of a network or other communication technology.
As will be described further with respect to FIG. 2 , when a device 100 - 106 records data, a time stamp from an appropriate timing device 108 - 114 is associated with the recording. This associated time stamp is then compared against one or more calendars 122 - 126 to identify a context for the recording. In one embodiment, if a calendar indicates one or more related entities, e.g., persons listed in a calendar entry, or based on some other cross-reference, then related entities may be provided with a copy of the recording by way of the data transfer application 128 - 132 .
FIG. 2 is a flowchart according to one embodiment of the invention for recording 200 a part (or portion) of an event, such as with a audio and/or visual transceiver (e.g., a cellular telephone, video phone, etc.), video camera, or other device configured to record into local or remote storage, and providing the recording to other event attendees.
A time stamp is acquired 202 , such as from an internal clock, or external reference source. The time stamp information is sent 204 to a calendar system along with at least an identifier of the user of the recording device. The calendar system may be any conventional or proprietary calendar, e.g., personal, corporate, general, etc. calendar, such as the Outlook calendar program provided by Microsoft Corporation of Redmond Wash., database application, or other application program that may associate time stamps with events (hereafter generally “calendar”). The user's identifier may be pre-associated with the user, temporarily associated, or prompted for during the recording process. It is assumed that an appropriate communication protocol or Application Programming Interface (API) is known to the recording device, thus allowing the recording device to communicate with the calendar irrespective of the particular characteristics or nature of the calendar.
In response to sending the time stamp information, the calendar inspects 206 the user's calendar to see what is on the calendar for the given time stamp information. If 208 an event is on the calendar for the time stamp information, the calendar sends 210 back to the recording device a description of an event. For example, the identified user may have a calendar entry indicating that the user is attending a social gathering for the user's work group. This description of the get together is sent 210 back to the recording device. The recording device can associate 212 the description with the recorded 200 part of the event, and store 214 the description and recorded part of the event in a data storage communicatively coupled to the recording device, e.g., in a local attached storage, wirelessly accessible remote storage, or the like. If 208 no entry is found, then an error handler 222 may be invoked, or a default description used for the event.
In one embodiment, the description is embedded within the recorded part of the event. For example, the event may be recorded with an Exchangeable Image File (EXIF) format, which is a standard format for storing information within digital photography image files using JPEG compression, in the DIG 35 , promulgated by the Digital Imaging consortium (see http://www-digitalimaging-org), in the graphics interchange format (GIF), or other data format providing for embedding data within the recorded part of the event. (To prevent inadvertent hyperlinks, the periods in the preceding Uniform Resource Locator (URL) were replaced with hyphens.) In one embodiment, data may be associated with the recorded part of the event to facilitate archiving, indexing, cataloging, cross-referencing, reviewing, and retrieving recordings.
In one embodiment, the recording device sends 216 the recorded part of the event, and associated description received from the calendar system, to a data transfer application program such as an E-mail program. In this embodiment, the calendar system also sends 218 the data transfer application program a list of other event attendees. It will be appreciated that various techniques may be used to identify event attendees. In one embodiment, the calendar sends a list of expected attendees, e.g., invitees, and it is later determined which attendees actually attended the event.
For example, the calendar for the user of the recording device may directly reference other attendees, such as by way of a meeting request that was used to schedule the event. All invited attendees, or perhaps just a subset, such as those meeting some criteria, are used to define the list of other event attendees. For example, the list of event attendees might only include those attendees that accepted the meeting request, or those attendees that have a special status indicating they should be included in the list irrespective of having accepted the invitation.
In one embodiment, if the calendar does not identify other event attendees, other calendars, perhaps based on a social or business structure, may be searched to determine whether a user corresponding to the searched calendar should be in the list of attendees. For example, all calendars for people in the user's work group might be searched for corresponding entries for the event. It will be appreciated that matching algorithms may be employed to compensate for manually written calendar entries for the event.
The data transfer program, having received the recorded part of the event, associated description, and the list of other event attendees, sends 220 each attendee a copy of the recorded part of the event. In one embodiment in which the data transfer program is an E-mail program, the subject and/or message body of the E-mail message sent to attendees comprises the associated description. The subject of the E-mail message, or message body, may also comprise statements reflecting the status of the attendee. For example, if a recipient did not attend the event, a standard message body might state “Sorry you could not make it to the event, but here is a recording of the event!” Similarly, other messages or graphics may be sent within a message for attendees that accepted but did not go, did not accept but went anyway, etc.
In one embodiment, categories and/or user preferences may alter distribution of data to attendees. For example, for certain events, such as holiday gatherings or birthdays, everyone in a work group, social group, etc. may automatically receive the recording of the event irrespective of whether they attended the event. However, user preferences may be used to override sending such messages.
FIG. 3 illustrates a flowchart according to another embodiment of the invention. In this embodiment, as with FIG. 2 , a recording device records 300 part of the event. A time stamp is acquired 302 , sent 304 to a calendar system along with an identifier of the user of the recording device, and in response the calendar system sends 306 back to the recording device a description of an event, if any. However, in this embodiment, 1 t and in contrast with FIG. 2 , the calendar system also sends 308 the recording device a list of event attendees. As discussed above for FIG. 2 , the list of attendees may be determined in various ways, e.g., based on attendees expected (invitees), attendees actually attending the event, based on status of attendee, etc.
The recording device can then store 310 the recorded 300 part of the event along with the description of the event, and the list of event attendees in a data storage communicatively coupled to the recording device, as well as send 312 the recorded part of the event, description, and list attendees to a data transfer program for distribution to event attendees. Thus, in this embodiment, the data transfer program need only communicate with the recording device in order to transfer event recordings to attendees. It will be appreciated that other communication configurations may be used, such as using a central repository for recorded parts of events and associated event attendees, where the transfer program retrieves recording and attendees from the central repository.
FIG. 4 and the following discussion are intended to provide a brief, general description of a suitable computing environment in which certain aspects of the illustrated invention may be implemented. An exemplary system for embodying, for example, the digital camera 102 or machines 116 , 118 , and 120 of FIG. 1 , includes a machine 400 having system bus 402 for coupling various machine components. Typically, attached to the bus are processors 404 , a memory 406 (e.g., RAM, ROM), storage devices 408 , a video interface 410 , and input/output interface ports 412 .
The system may also include embedded controllers, such as Generic or Programmable Logic Devices or Arrays (PLD, PLA, GAL, PAL), Field-Programmable Gate Arrays (FPGA), Application Specific Integrated Circuits (ASIC), single-chip computers, smart cards, or the like, and the system is expected to operate in a networked environment using physical and/or logical connections to one or more remote systems 414 , 416 through a network interface 418 , modem 420 , or other pathway. Systems may be interconnected by way of a wired or wireless network 422 , including an intranet, the Internet, local area networks, wide area networks, cellular, cable, laser, satellite, microwave, “Blue Tooth” type networks, optical, infrared, or other carrier.
The invention may be described by reference to program modules for performing tasks or implementing abstract data types, e.g., procedures, functions, data structures, application programs, etc., that may be stored in memory 406 and/or storage devices 408 and associated storage media, e.g., hard-drives, floppy-disks, optical storage, magnetic cassettes, tapes, flash memory cards, memory sticks, digital video disks or biological storage.
Illustrated methods and corresponding written descriptions are intended to illustrate machine-accessible media storing directives, or the like, which may be incorporated into single and multi-processor machines, portable computers, such as handheld devices including Personal Digital Assistants (PDAs), cellular telephones, etc. An artisan will recognize that program modules may be high-level programming language constructs, or low-level hardware instructions and/or contexts, that may be utilized in a compressed or encrypted format, and may be used in a distributed network environment and stored in local and/or remote memory.
Thus, for example, with respect to the illustrated embodiments, assuming machine 400 operates as a recording device for an event, then remote devices 414 , 416 may respectively be a machine operating a calendar for a user of the recording device, and an a remote clock source to identify when the recording device was operating. It will be appreciated that remote machines 414 , 416 may be configured like machine 400 , and therefore include many or all of the elements discussed for machine. It should also be appreciated that machines 400 , 414 , 416 may be embodied within a single device, or separate communicatively-coupled components.
Having described and illustrated the principles of the invention with reference to illustrated embodiments, it will be recognized that the illustrated embodiments can be modified in arrangement and detail without departing from such principles. And, even though the foregoing discussion has focused on particular embodiments, it is understood other configurations are contemplated. In particular, even though expressions such as “in one embodiment,” “in another embodiment,” or the like are used herein, these phrases are meant to generally reference embodiment possibilities, and are not intended to limit the invention to particular embodiment configurations. As used herein, these terms may reference the same or different embodiments, and unless indicated otherwise, embodiments are combinable into other embodiments.
Consequently, in view of the wide variety of permutations to the above-described embodiments, the detailed description is intended to be illustrative only, and should not be taken as limiting the scope of the invention. What is claimed as the invention, therefore, is all such modifications as may come within the scope and spirit of the following claims and equivalents thereto. | Automatic annotation of data recorded by a device. A portion of an event may be recorded as an image, movie, sound byte, audio recording, etc., and contemporaneous to the recording, a time value (which may encode a calendar date) is determined. The time value is looked up on a calendar, and a description of the event is read from the calendar and used to automatically annotate the recording. |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to communication systems in which communications are performed among three or more communication devices, the communication devices which constitute the communication systems, and seating-order determination devices. The present invention further relates to group-determination-table generation devices for generating a group determination table used in the seating-order determination devices and the communication methods.
[0003] 2. Description of the Related Art
[0004] In conventional teleconference systems, images and sound generated at a plurality of conference rooms distant from each other are transferred among the conference rooms through a network, and the images and sound sent from the other conference rooms are reproduced at each conference room. This allows a conference to be held as if all participants sat around one table.
[0005] In these conventional teleconference systems, conference participants are allowed to talk at the same time in each conference room.
[0006] In an actual conference, in some cases, some conversation groups are made among participants according to the situation of a progress in the conference, and topics are different in the groups. Each group is made tentatively by a part of conference participants for a certain topic, and the group is flexible. More specifically, a conversation group may be made according to a progress in the conference; persons constituting a group may be changed; and one group may be further divided into a plurality of groups. The structures of groups are always being changed.
[0007] In the conventional teleconference systems, each participant sees the other participants on monitor devices. Each monitor device corresponds to one participant, and their relationship is fixed. In a conference having six participants, for example, each participant sees the other five participants on five monitor devices. Each monitor device displays an assigned participant. In other words, in a teleconference terminal used by one participant, five monitor devices MDa, MDb, MDc, MDd, and MDe display the other participants HMa, HMb, HMc, HMd, and HMe in an always fixed manner.
[0008] Assuming that each monitor device is handled as the seat of the participant corresponding to the monitor device, it can be considered that the order of seats (seating order) can be made changeable to some extent.
[0009] In other words, the five monitor devices MDa, MDb, MDc, MDd, and MDe arranged in this order do not display the participants HMa, HMb, HMc, HMd, and HMe in a fixed manner, and the relationship between the monitor devices and the participants is made changeable.
[0010] With this feature, when a group is formed among participants, the seating order can be changed according to the formed group. When the user of the terminal and the participants HMb and HMd form a group, for example, if the seating order is changed such that the monitor device MDa displays the participants HMb and the monitor device MDb displays the participants HMd, the group is made to have a convenient condition for their conversation.
[0011] The seating order is changed, for example, by the seating-order-changing operations of the user. It is not realistic that the user performs a seating-order changing operation according to a group formed or released during a conference. This means that the user needs to perform a very troublesome operation. In addition, especially during a conference, the user wants to concentrate on the conference without performing any operations. Furthermore, a terminal user is not necessarily familiar with operations.
[0012] It can be considered that a system operator is assigned to seating-order-changing operations. It is also unrealistic, however, because extra man-power is required, and an operator usually cannot correctly understand conversation groups which always change their participants.
[0013] With the above-described reasons, even in a system which allows a seating order to be changed, the feature is usually not utilized.
SUMMARY OF THE INVENTION
[0014] The present invention has been made in consideration of the foregoing points. It is an object of the present invention to provide a communication system, such as a teleconference system, a communication device, a seating-order determination device, a communication method, a recording medium, a group-determination-table generating method, and a group-determination-table generating device, in which a seating order can be appropriately changed according to conversations which flexibly progress among participants to provide a more suitable communication-conversation environment.
[0015] The foregoing object is achieved in one aspect of the present invention through the provision of a communication system including at least three communication devices, and a seating-order determination device for generating seating-order information at each point of time for information sent from each communication device and for transmitting the seating-order information to each communication device.
[0016] Each communication device may control the output position of the information sent from other communication devices, according to the seating-order information to output the information sent from the other communication devices in a seating order corresponding to the seating-order information.
[0017] In this case, the seating order is always automatically changed to the most appropriate condition according to the progress of a conference and the state of conversations to provide the user with a suitable conference environment and a suitable communication environment.
[0018] The seating-order determination device may generate the seating-order information for the information sent from each communication device according to the degree of attention which the user of each communication device pays to the information sent from each communication device. In this case, the most appropriate seating order is implemented.
[0019] The seating-order determination device may group the information sent from each communication device according to the degree of attention which each user pays to the information sent from each communication device, and generate the seating-order information according to the result of grouping. In this case, the seating order is automatically changed with conversation groups being taken into account and a suitable teleconference system is implemented.
[0020] The seating-order information may be generated such that information belonging to the same group is arranged. In this case, the seating order is changed so as to collect the members of groups.
[0021] The seating-order information may also be generated such that information belonging to the same group is dispersed almost uniformly. In this case, the user is provided with an easy-to-converse environment.
[0022] When the seating order is changed according to the seating-order information, each communication device may output indication information indicating a change in the seating order to the user, for example, by image information or audio information. In this case, the user can understand that the seating order is to be changed, and the user is prevented from confusing with a change in the seating order.
[0023] When the seating order is changed according to grouping, each communication device may output indication information indicating the state of grouping to the user. In this case, the user successfully understands the states of conversation groups. This indication information also helps the user understand the current condition. As the indication information, a background image color may be used, which is one of the most easy-to-understand indications.
[0024] The degree of attention may be determined according to user-behavior detection information or information specified by the user. In this case, the degree of attention is suited as a reference for a change in the seating order. More specifically, when the user-behavior detection information includes the lines of sight or a face direction of the user, most suitable control is implemented by the use of a natural operation of the user.
[0025] The grouping may be performed according to the statistical relationship between a group structure and the degree of attention which the user of each communication device pays to the information sent from the other communication devices. In this case, the grouping is suited to generate the seating-order information.
[0026] Therefore, when a group-determination-table generating method and a group-determination-table generating device according to the present invention hold the statistical relationship, a suitable operation is implemented for changing the seating order.
[0027] The foregoing object is achieved in another aspect of the present invention through the provision of a seating-order determination device provided for a communication system having at least three communication devices, including seating-order-information generating means for generating seating-order information at each point of time for information sent from each communication device; and transmitting means for sequentially transmitting the seating-order information generated by the seating-order-information generating means to each communication device.
[0028] The foregoing object is achieved in still another aspect of the present invention through the provision of a communication device in a communication system including at least three communication devices communicating with each other, including receiving means for receiving information and seating-order information sent from other communication devices; attention-degree-information generating means for detecting the degree of attention which the user pays to the information sent from the other communication devices to generate attention-degree information; transmitting means for transmitting the attention-degree information generated by the attention-degree-information generating means; presenting means for presenting the information sent from the other communication devices; and information manipulation and distribution means for controlling the output positions of the information sent from the other communication devices according to the seating-order information received by the receiving means to output the information sent from the other communication devices in a seating order corresponding to the seating-order information.
[0029] The foregoing object is achieved in yet another aspect of the present invention through the provision of a group-determination-table generating device for generating a group determination table used for grouping information sent from each communication device according to the degree of attention of the user of each communication device in a communication system having at least three communication devices, including statistics means for reading attention-degree patterns indicating the degree of attention which the user of each communication device pays to information sent from other communication devices and group structure patterns indicating the group state of each user, and for collecting statistics on the attention-degree patterns and the group structure patterns; determination means for determining the correspondence between each attention-degree pattern and one of the group structure patterns from the statistics obtained by the statistics means; and determination-table generating means for generating a group determination table indicating attention-degree patterns and group structure patterns for which the correspondence is determined by the determination means.
[0030] The foregoing object is achieved in yet still another aspect of the present invention through the provision of a communication method for a communication system having at least three communication devices, including a seating-order generating step of generating seating-order information at each point of time for information sent from each communication device; and a transmitting step of sequentially transmitting the seating-order information generated in the seating-order generating step to each communication device.
[0031] The foregoing object is achieved in a further aspect of the present invention through the provision of a seating-order determination method for a seating-order determination device provided for a communication system having at least three communication devices, including a seating-order-information generating step of generating seating-order information at each point of time for information sent from each communication device; and a transmitting step of sequentially transmitting the seating-order information generated in the seating-order-information generating step to each communication device.
[0032] The foregoing object is achieved in a still further aspect of the present invention through the provision of a communication method for a communication device in a communication system including at least three communication devices communicating with each other, including a receiving step of receiving information and seating-order information sent from other communication devices; an attention-degree-information generating step of detecting the degree of attention which the user pays to the information sent from the other communication devices to generate attention-degree information; a transmitting step of transmitting the attention-degree information generated in the attention-degree-information generating step; a presenting step of presenting the information sent from the other communication devices; and an information manipulation and distribution step of controlling the output positions of the information sent from the other communication devices according to the seating-order information received in the receiving step to output the information sent from the other communication devices in a seating order corresponding to the seating-order information.
[0033] The foregoing object is achieved in a yet further aspect of the present invention through the provision of a group-determination-table generating method for a group-determination-table generating device for generating a group determination table used for grouping information sent from each communication device according to the degree of attention of the user of each communication device in a communication system having at least three communication devices, including a statistics step of reading attention-degree patterns indicating the degree of attention which the user of each communication device pays to information sent from other communication devices and group structure patterns indicating the group state of each user, and of collecting statistics on the attention-degree patterns and the group structure patterns; a determination step of determining the correspondence between each attention-degree pattern and one of the group structure patterns from the statistics obtained in the statistics step; and a determination-table generating step of generating a group determination table indicating attention-degree patterns and group structure patterns for which the correspondence is determined in the determination step.
[0034] The foregoing object is achieved in a yet still further aspect of the present invention through the provision of a recording medium for storing a processing program related to seating information for information sent from each communication device in a communication system having at least three communication devices, the processing program including a seating-order generating step of generating seating-order information at each point of time for information sent from each communication device; and a transmitting step of sequentially transmitting the seating-order information generated in the seating-order generating step to each communication device.
[0035] The foregoing object is achieved in an additional aspect of the present invention through the provision of a recording medium for storing a processing program related to seating-order determination in a seating-order determination device provided for a communication system having at least three communication devices, the processing program including a seating-order-information generating step of generating seating-order information at each point of time for information sent from each communication device; and a transmitting step of sequentially transmitting the seating-order information generated in the seating-order-information generating step to each communication device.
[0036] The foregoing object is achieved in a still additional aspect of the present invention through the provision of a recording medium for storing a processing program related to communication in a communication device of a communication system including at least three communication devices communicating with each other, the processing program including a receiving step of receiving information and seating-order information sent from other communication devices; an attention-degree-information generating step of detecting the degree of attention which the user pays to the information sent from the other communication devices to generate attention-degree information; a transmitting step of transmitting the attention-degree information generated in the attention-degree-information generating step; a presenting step of presenting the information sent from the other communication devices; and an information manipulation and distribution step of controlling the output positions of the information sent from the other communication devices according to the seating-order information received in the receiving step to output the information sent from the other communication devices in a seating order corresponding to the seating-order information.
[0037] The foregoing object is achieved in a yet additional aspect of the present invention through the provision of a recording medium for storing a processing program related to group-determination-table generation in a group-determination-table generating device for generating a group determination table used for grouping information sent from each communication device according to the degree of attention of the user of each communication device in a communication system having at least three communication devices, the processing program including a statistics step of reading attention-degree patterns indicating the degree of attention which the user of each communication device pays to information sent from other communication devices and group structure patterns indicating the group state of each user, and of collecting statistics on the attention-degree patterns and the group structure patterns; a determination step of determining the correspondence between each attention-degree pattern and one of the group structure patterns from the statistics obtained in the statistics step; and a determination-table generating step of generating a group determination table indicating attention-degree patterns and group structure patterns for which the correspondence is determined in the determination step.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1 is a block diagram of a teleconference system according to an embodiment of the present invention.
[0039] FIG. 2 is a block diagram of a teleconference device according to the embodiment.
[0040] FIG. 3 is a view showing a method for generating attention-degree information according to the embodiment.
[0041] FIG. 4 is a view showing another method for generating attention-degree information according to the embodiment.
[0042] FIG. 5 is a block diagram of a seating-order determination device according to the embodiment.
[0043] FIG. 6 is a view showing the initial state of an attention-destination table according to the embodiment.
[0044] FIG. 7 is a view showing the initial state of a group table according to the embodiment.
[0045] FIG. 8 is a flowchart of initialization processing applied to the attention-destination table and the group table according to the embodiment.
[0046] FIG. 9 is a flowchart of processing to be performed when attention-degree information is generated according to the embodiment.
[0047] FIG. 10 is a view showing an attention-destination table to which attention-degree information has been input according to the embodiment.
[0048] FIG. 11 is a flowchart of processing for inputting the contents of the attention-destination table to the group table according to the embodiment.
[0049] FIG. 12 is a view showing a group table obtained during the processing according to the embodiment.
[0050] FIG. 13 is a view showing an attention-destination table obtained during the processing according to the embodiment.
[0051] FIG. 14 is a view showing a group table obtained during the processing according to the embodiment.
[0052] FIG. 15 is a view showing an attention-destination table obtained during the processing according to the embodiment.
[0053] FIG. 16 is a view showing a group table obtained during the processing according to the embodiment.
[0054] FIG. 17 is a view showing an attention-destination table obtained during the processing according to the embodiment.
[0055] FIG. 18 is a view showing a group table obtained during the processing according to the embodiment.
[0056] FIG. 19 is a view showing an attention-destination table obtained during the processing according to the embodiment.
[0057] FIG. 20 is a view showing a group table obtained during the processing according to the embodiment.
[0058] FIG. 21 is a view showing an attention-destination table obtained during the processing according to the embodiment.
[0059] FIG. 22 is a view showing a group table obtained during the processing according to the embodiment.
[0060] FIG. 23 is a view showing an attention-destination table obtained during the processing according to the embodiment.
[0061] FIG. 24 is a view showing a group table obtained during the processing according to the embodiment.
[0062] FIG. 25 is a view showing an attention-destination table obtained during the processing according to the embodiment.
[0063] FIG. 26 is a flowchart of seating-order determination processing according to the embodiment.
[0064] FIG. 27A and FIG. 27B are views showing example seating-order determination according to the embodiment.
[0065] FIG. 28A , FIG. 28B , and FIG. 28C are views showing another example seating-order determination according to the embodiment.
[0066] FIG. 29 is a view showing example distributed-seating-order determination according to the embodiment.
[0067] FIG. 30 is a block diagram of an information manipulation and distribution section according to the embodiment.
[0068] FIG. 31 is a block diagram of an image manipulation section according to the embodiment.
[0069] FIG. 32 is a block diagram of an audio manipulation section according to the embodiment.
[0070] FIG. 33 is a block diagram of an information distribution section according to the embodiment.
[0071] FIG. 34A and FIG. 34B are views showing example image processing applied when the seating order is changed according to the embodiment.
[0072] FIG. 35A , FIG. 35B , FIG. 35C , and FIG. 35D are views showing another example image processing applied when the seating order is changed according to the embodiment.
[0073] FIG. 36A , FIG. 36B , and FIG. 36C are views showing still another example image processing applied when the seating order is changed according to the embodiment.
[0074] FIG. 37A and FIG. 37B are views showing example image processing for indicating groups according to the embodiment.
[0075] FIG. 38 is a view showing group patterns according to the embodiment.
[0076] FIG. 39 is a view showing the frequency table of group patterns for attention patterns according to the embodiment.
[0077] FIG. 40 is a view showing a group determination table according to the embodiment.
[0078] FIG. 41 is a view showing an attention-pattern conversion table according to the embodiment.
[0079] FIG. 42 is a view showing a group conversion table according to the embodiment.
[0080] FIG. 43 is a view showing a representative frequency table according to the embodiment.
[0081] FIG. 44 is a view showing a representative-group determination table according to the embodiment.
[0082] FIG. 45 is a view showing a group inverted-conversion table according to the embodiment.
[0083] FIG. 46A and FIG. 46B are views showing group conversion methods according to the embodiment.
[0084] FIG. 47 is a functional block diagram of a group-determination-table generating device according to the embodiment.
[0085] FIG. 48 is a flowchart of processing for generating the representative frequency table according to the embodiment.
[0086] FIG. 49 is a flowchart of processing for generating the representative-group determination table according to the embodiment.
[0087] FIG. 50 is a flowchart of processing for generating the group determination table according to the embodiment.
[0088] FIG. 51 is a view showing a satisfaction-degree weight table according to the embodiment.
[0089] FIG. 52 is a view showing example degrees of attentions paid to participants according to the embodiment.
[0090] FIG. 53 is a view showing the names of seats according to the embodiment.
[0091] FIG. 54 is a view showing an example seating order according to the embodiment.
[0092] FIG. 55 is a flowchart of sight-line detection processing according to the embodiment.
[0093] FIG. 56 is a view showing detection of both-end positions of an eye according to the embodiment.
[0094] FIG. 57 is a view showing a nostril-position detection area according to the embodiment.
[0095] FIG. 58 is a view showing the both-end positions of eyes, nostril positions, and eyeball-center positions according to the embodiment.
[0096] FIG. 59 is a view showing detection of a sight-line direction according to the embodiment.
[0097] FIG. 60 is a view showing a method for obtaining a line which makes the secondary moment of a predetermined set of pixels minimum, according to the embodiment.
[0098] FIG. 61 is a flowchart of processing for detecting a face direction according to the embodiment.
[0099] FIG. 62A and FIG. 62B are views showing original images used for detecting a face direction according to the embodiment.
[0100] FIG. 63A and FIG. 63B are views showing hair areas and skin areas used for detecting a face direction according to the embodiment.
[0101] FIG. 64A and FIG. 64B are views showing the centers of gravity of the hair areas and of the skin areas according to the embodiment.
[0102] FIG. 65 is a view showing an example relationship between a difference and an angle during face-direction detection according to the embodiment.
[0103] FIG. 66 is an outlined internal view of a specific monitor device, viewed from a side thereof, according to the embodiment.
[0104] FIG. 67 is an outlined elevation of the specific monitor device according to the embodiment.
[0105] FIG. 68 is a block diagram of an actual structure implementing a signal processing device and a seating-order determination device in each teleconference device in the teleconference system according to the embodiment.
[0106] FIG. 69 is a view showing an outlined structure of another teleconference device which displays conference participants on a screen and disposes sound images by speakers according to the embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0107] A teleconference system according to an embodiment of the present invention will be described below in the following order.
[0108] 1. Structure of communication system
[0109] 2. Structure of teleconference device
[0110] 3. Structure of seating-order determination device
[0111] 4. Grouping processing in the seating-order determination device
[0112] 5. Seating-order determination operation through grouping in the seating-order determination device
[0113] 6. Seating-order changing processing performed according to seating-order information in a teleconference device
[0114] 7. First example of grouping processing which uses a statistical relationship in the seating-order determination device
[0115] 8. Second example of grouping process which uses a statistical relationship in the seating-order determination device
[0116] 9. Seating-order determination operation not through grouping in the seating-order determination device
[0117] 10. Attention-degree-information generating operation in a teleconference device
[0118] 11. Structure of monitor device
[0119] 12. Example structure of each device
[0120] 1. Structure of Communication System
[0121] FIG. 1 shows an outlined structure of a teleconference system according to an embodiment of the present invention. In the present specification, a system refers to the whole structure formed of a plurality of devices and sections.
[0122] In the teleconference system shown in FIG. 1 , teleconference devices TCD 1 to TCDn are assigned to conference participants HM 1 to HMn located at a plurality of (one to n) positions. The teleconference devices TCD 1 to TCDn are connected through a communication network NT formed, for example, of an integrated services digital network (ISDN).
[0123] When the conference participants HM 1 to HMn do not need to be distinguished from each other, they are hereinafter collectively called conference participants HM. In the same way, when the teleconference devices TCD 1 to TCDn do not need to be distinguished from each other, they are hereinafter collectively called teleconference devices TCD. In FIG. 1 , an IDSN is taken as an example of the communication network NT. Instead of an ISDN, other transfer media, such as cable television networks, the Internet, and digital satellite communication, can be used.
[0124] Each teleconference device TCD captures the image data and audio data of the corresponding conference participant HM; performs mutual communication with other teleconference devices TCD through the communication network NT; and can reproduce the image data and audio data (can monitor the images and sound) of the other conference participants HM sent from the other teleconference devices TCD.
[0125] 2. Structure of Teleconference Device
[0126] Each teleconference device TCD constituting the teleconference system has a structure shown in FIG. 2 .
[0127] The teleconference devices TCD 1 to TCDn have the same structure. FIG. 2 shows a detailed example structure of the teleconference device TCD 1 as a representative of the plurality of teleconference devices TCD 1 to TCDn.
[0128] The teleconference device TCD 1 includes at least a signal processing device SPD 1 connected to the communication network NT, for transmitting and receiving signals to and from the other teleconference devices TCD 2 to TCDn which constitute the teleconference system and for applying signal processing described later to signals transmitted and received; and monitor devices MD 2 to MDn in which the image data and audio data of the conference participants HM 2 to HMn transmitted from the other teleconference devices TCD 2 to TCDn constituting the teleconference system can be monitored correspondingly to the teleconference devices TCD 2 to TCDn.
[0129] When the monitor devices MD 2 to MDn do not need to be distinguished from each other, they are hereinafter collectively called monitor devices MD.
[0130] The users of the teleconference devices TCD 1 to TCDn are fixed to the conference participants HM 1 to HMn. The relationships between the monitor devices MD in the teleconference devices and the information of conference participants HM displayed thereon are not fixed but dynamically changed according to seating-order information described later.
[0131] For simplicity, until a change of a seating order is described, a description will be given under the assumption that the monitor devices MD 1 to MDn correspond to the conference participants HM 1 to HMn located in the teleconference devices TCD 1 to TCDn, respectively.
[0132] The signal processing device SPD 1 of the teleconference device TCD 1 includes a network connection terminal TN 1 for connecting to the communication network NT; an information transmitting and receiving section TRB 1 for transmitting and receiving information to and from the communication network NT; an information manipulation and distribution section PB 1 for applying information manipulation and distribution processing described later to signals to be sent to monitor device MD 2 to MDn; an attention-degree-information generating section JB 1 for generating attention-degree-information used for dynamically changing a seating order during a conference, as described later; output terminals TO 2 to TOn for outputting signals separately to the monitor devices MD 2 to MDn; input terminals TI 2 to TIn for receiving signals separately from the monitor devices MD 2 to MDn; and an input terminal TS for receiving a signal from a switch SW, which generates switch-pressing information described later, used for generating the attention-degree information.
[0133] A detailed structure of each of the monitor devices MD 2 to MDn will be described later. Each monitor device MD includes, as main components, at least a speaker provided at the front side of the body of the monitor device, and a display section disposed such that its screen G is directed in a predetermined direction (such as a direction towards the participant HM 1 ).
[0134] At least one monitor device MD among the monitor devices MD 2 to MDn is provided with a microphone for capturing sound around the teleconference device TCD 1 and the sound of what the conference participant HM 1 says, and a camera (such as a video camera) for capturing an image of the conference participant HM 1 .
[0135] It is preferable that a monitor device provided with a microphone and a camera be disposed at the position of a monitor device (monitor device MDm in the case shown in FIG. 2 ) which directly faces the conference participant HM 1 . It is also possible that all the monitor devices MD 2 to MDn are provided with microphones and cameras.
[0136] Image data captured by the camera and audio data captured by the microphone in the monitor device MD are transmitted to the other teleconference devices TCD 2 to TCDn through the signal processing device SPD 1 and the communication network NT.
[0137] Images based on image data sent from the teleconference devices TCD 2 to TCDn are displayed on the display sections of the monitor devices MD 2 to MDn, and sound based on audio data sent from the teleconference devices TCD 2 to TCDn is output from the speakers of the monitor devices.
[0138] In other words, the monitor devices MD 2 to MDn correspond to the teleconference devices TCD 2 to TCDn with one-to-one correspondence. For example, images based on image data (image data of the conference participant HM 2 and the surrounding thereof) captured by the camera of the teleconference device TCD 2 and sent through the communication network NT are displayed on the screen G of the display section of the monitor device MD 2 , and sound based on audio data (audio data of what the conference participant HM 2 says) captured by the microphone of the teleconference device TCD 2 and sent through the communication network NT is output from the speaker of the monitor device MD 2 .
[0139] In the same way, images based on image data captured by the camera of the teleconference device TCD 3 and transmitted are displayed on the screen of the display section of the monitor device MD 3 , and sound based on audio data captured by the microphone of the teleconference device TCD 3 and transmitted is output from the speaker of the monitor device. The other monitor devices MD work in the same way. Images sent from teleconference devices TCD are displayed and sound is output.
[0140] As described above, however, the relationships between the monitor devices MD 2 to MDn and the teleconference devices TCD 2 to TCDn are not fixed but is dynamically changed as a so-called seating-order change. Therefore, the above-described one-to-one correspondence relationship is a tentative correspondence relationship such as that used in a system initial condition.
[0141] It can be considered that image data transmitted and received through the communication network NT among the teleconference devices TCD 1 to TCDn includes still-picture data as well as motion-picture data.
[0142] The monitor devices MD 2 to MDn are disposed as shown in FIG. 2 as if the conference participant HM 1 , who is in a conference room having the teleconference device TCD 1 , and the other conference participants HM 2 to HMn (those displayed on the display sections of the monitor devices MD 2 to MDn) were around one table to have a conference. Assuming that six teleconference devices TCD are used in the teleconference system and each teleconference device TCD is provided with five monitor devices, the five monitor devices can be disposed as shown in the figure such that a conference participant HM and the five monitor devices MD form, for example, a regular hexagon.
[0143] The attention-degree-information generating section JB of the signal processing device SPD in each teleconference device TCD generates attention-degree information used when a seating order is dynamically changed during a conference, as described below.
[0144] The attention-degree-information generating section JB 1 of the signal processing device SPD 1 in the teleconference device TCD 1 is taken as an example among the attention-degree-information generating sections JB 1 to JBn corresponding to the teleconference devices TCD 1 to TCDn, and its operation will be described below.
[0145] The attention-degree-information generating section JB 1 detects the degrees of attention which the conference participant HM 1 pays to the other conference participants according to image data sent from the camera, for example, of the monitor device MDm disposed in the front of the conference participant HM 1 , and generates attention-degree information used for dynamically changing the seating order, as described later, according to the result of detection.
[0146] The degrees of attention which the conference participant HM 1 pays to the other conference participants include how much (more specifically, analog values or stepped values indicating the state in which) the conference participant HM 1 pays attention to each of the monitor devices MD 2 to MDn as well as whether (more specifically, digital “0” or “1” indicating whether) the conference participant HM 1 pays attention in a direction toward each of the monitor devices MD 2 to MDn or in another direction.
[0147] The attention-degree-information generating section JB 1 analyzes the image data of the conference participant HM 1 , sent from the camera of the monitor device MDm to detect the direction in which the conference participant HM 1 faces, every unit periods. Details thereof will be described later.
[0148] More specifically, the attention-degree-information generating section JB 1 detects a period Ij as shown in FIG. 3( a ) as information indicating the direction in which the conference participant HM 1 faces and a period for which the conference participant HM 1 continues to face in the direction. In this case, Ij is one of values 2 to n, which correspond to the other conference participants HM 2 to HMn, or 0, which indicates none of the conference participants HM 2 to HMn. The attention-degree-information generating section JB 1 detects a period 12 in which the conference participant HM 1 faces the monitor device MD 2 on which an image of the conference participant HM 2 is displayed, a period I 3 in which the conference participant HM 1 faces the monitor device MD 3 on which an image of the conference participant HM 3 is displayed, a period Im in which the conference participant HM 1 faces the monitor device MDm on which an image of the conference participant HMm is displayed, a period In−1 in which the conference participant HM 1 faces the monitor device MDn−1 on which an image of the conference participant HMn−1 is displayed, a period In in which the conference participant HM 1 faces the monitor device MDn on which an image of the conference participant HMn is displayed, or a period I 0 in which the conference participant HM 1 faces. none of the monitor devices MD 2 to MDn.
[0149] Then, the attention-degree-information generating section JB 1 detects a period longer than a time Tcont among detected periods, some of I 2 to In and I 0 . When the attention-degree-information generating section JB 1 detects a period longer than the time Tcont, it generates information (Hi:Aj) indicating that the conference participant HM 1 pays attention to the conference participant corresponding to the detected period, such as those shown in FIG. 3( b ).
[0150] In the information (Hi:Aj), “i” corresponds to a conference participant HMi (for example, “1” for HM 1 ), and “j” corresponds to one of the other conference participants HMj (i≠j) (2 to n corresponding to the other conference participants HM 2 to HMn when “i” is 1) or 0, which corresponds to none of the conference participants.
[0151] More specifically, a description is made in the case shown in FIG. 3 . When the attention-degree-information generating section JB 1 detects. periods I 3 , I 0 , and I 2 as periods longer than the time Tcont among detected periods, some of I 2 to In and I 0 , shown in FIG. 3( a ), the attention-degree-information generating section JB 1 generates, as attention-degree information, information (H 1 :A 3 ) indicating that the conference participant HM 1 pays attention to the conference participant HM 3 corresponding to the detected period I 3 ; information (H 1 :A 0 ) indicating that the conference participant RM 1 pays attention to none of the monitor devices MD or pay attention to something other than the monitor devices MD, corresponding to the detected period I 0 ; and information (H 1 :A 2 ) indicating that the conference participant HM 1 pays attention to the conference participant HM 2 corresponding to the detected period 12 , as shown in FIG. 3( b ).
[0152] The attention-degree-information generating section JB 1 may generate attention-degree information according to the detection of a period Ij and switch-pressing information sent from the switch SW. More specifically, when the attention-degree-information generating section JB 1 detects periods Ij serving as information indicating the direction in which the conference participant HM 1 faces and a period in which the conference participant HM 1 faces in the direction, as shown in FIG. 4( a ), and receives switch-pressing ON signals, such as those shown in FIG. 4( b ), obtained when the conference participant HM 1 presses the switch SW during the detected periods, some of I 2 to In and I 0 , the attention-degree-information generating section JB 1 generates information (H 1 :Aj), such as those shown in FIG. 4( c ), indicating that, during a period when the switch-pressing signal is ON, the conference participant HM 1 pays attention to the conference participant corresponding to the signal. In the case shown in FIG. 4 , when the attention-degree-information generating section JB 1 detects 13 and 14 as periods when the switch-pressing signal is ON, among the detected periods, some of I 2 to In and I 0 , the attention-degree-information generating section JB 1 generates, as attention-degree information, information (H 1 :A 3 ) indicating that the conference participant HM 1 pays attention to the conference participant HM 3 corresponding to the detected period I 3 , and information (H 1 :A 4 ) indicating that the conference participant HM 1 pays attention to the conference participant HM 4 corresponding to the detected period 14 , as shown in FIG. 4( c ).
[0153] In addition to the above cases, it is also possible that the conference participant HM 1 explicitly specifies the direction in which the conference participant HM 1 pays attention. For example, pushbuttons corresponding to the other conference participants HM 2 to HMn and a pushbutton corresponding to a case in which the conference participant HM 1 pays attention to none of those participants are prepared, and the conference participant HM 1 specifies the direction in which the conference participant HM 1 pays attention by pressing the corresponding pushbutton. In this case, pushbutton-pressing information serves as the attention-degree information.
[0154] 3. Structure of Seating-Order Determination Device
[0155] Attention-degree information generated by the attention-degree-information generating section JB 1 by determining whom the conference participant HM 1 pays attention among the conference participants HM 2 to HMn according to a behavior or a designation of the conference participant HM 1 as described above is transmitted to the information transmitting and receiving section TRB 1 in the signal processing device SPD 1 , and then to a seating-order determination device GJD via the network connection terminal TN 1 through the communication network NT.
[0156] The seating-order determination device GJD is structured as shown in FIG. 5 .
[0157] In FIG. 5 , the seating-order determination device GJD is provided with a network connection terminal 72 for connecting to the communication network NT; an information transmitting and receiving section 70 for transmitting and receiving information to and from the communication network NT; and a seating-order determiner 71 for determining a seating order according to attention-degree information sent from the teleconference devices TCD 1 to TCDn, for generating seating-order information indicating the seating order, and for sending the seating-order information to the information manipulation and distribution sections PB of the teleconference devices TCD 1 to TCDn.
[0158] More specifically, in the seating-order determination device GJD, the information transmitting and receiving section 70 picks up the attention-degree information sent from the teleconference devices TCD 1 to TCDn among signals passing through the communication network NT, and sends the attention-degree information to the seating-order determiner 71 . The seating-order determiner 71 determines the seating order of the conference participants HM 1 to HMn attending the conference through the teleconference devices TCD 1 to TCDn, and generates seating-order information indicating the determined seating order.
[0159] The information transmitting and receiving section 70 transmits the generated seating-order information to the communication network NT to send it to the teleconference devices TCD 1 to TCDn.
[0160] Although details will be described later, the teleconference devices TCD 1 to TCDn receive the seating-order information sent from the seating-order determination device GJD at the information manipulation and distribution sections PB; and the information manipulation and distribution sections PB determine the correspondences between conference participants HM and monitor devices MD according to the seating-order information as described later, applies video and audio manipulation such that, for example, a change in seating order is easy to understand, and sends images and sound related to the conference participants HM corresponding to the monitor devices MD 2 to MDn to implement the determined seating order.
[0161] 4. Grouping Processing in the Seating-Order Determination Device
[0162] Various methods for determining a seating order can be considered for the seating-order determination device GJD. A method can be considered as an example, in which a conversation group to which conference participants HM 1 to HMn belong is determined and then a seating order is determined according to the result of group determination such that participants belonging to the same group are set close to each other.
[0163] A process for determining a conversation group in the seating-order determination device GJD will be described below before seating-order determination processing performed according to a group is described.
[0164] Various group-determination rules used in the seating-order determination device GJD can be considered. In the following description, a rule in which a link is made between a person who pays attention to another person and the another person, who attracts attention, and one group is formed of persons who are coupled directly or indirectly by links is used as an example. Details of a group determination and update process performed by the rule according to attention-degree information in the seating-order determiner 71 of the seating-order determination device GJD will be described below. In this rule, one group is formed of persons who directly or indirectly pay attention to others, and the others, who attract attention directly or indirectly.
[0165] A condition in which a person directly or indirectly pays attention to another person, and the another person attracts attention directly or indirectly will be described with the following example. It is assumed, as an example, that a person A pays attention to a person B, and the person B pays attention to a person C. In this example, it is considered that the person A pays attention to the person B “directly” (the person B also pays attention to the person C “directly”) and the person B attracts attention “directly;” and the person A pays attention to the person C “indirectly (through the person B)” and the person C attracts the attention of the person A “indirectly (through the person B).” In this example, there is only one person, the person B, between the person A and the person C. But, there may be a plurality of persons between the person A and the person C.
[0166] The seating-order determiner 71 holds an attention-destination table formed of an “individual number” column indicating numbers assigning to conference participants attending a conference held with this teleconference system; an “attention-destination number” column indicating the numbers of conference participants whom the conference participants HM 1 to HMn using the teleconference devices TCD 1 to TCDn pay attention; and a “whether registration has been made to group table” column indicating whether registration has been made to a group table, as shown in FIG. 6 .
[0167] The seating-order determiner 71 also holds a group table formed of a “group number” column indicating numbers assigned to groups formed in the teleconference system; a “number of members” column indicating the number of members belonging to each group among the conference participants; and a “member” column indicating conference participants belonging to the groups, as shown in FIG. 7 .
[0168] The seating-order determiner 71 performs initialization at the start of communication prior to receiving attention-degree information, as shown in FIG. 8 .
[0169] More specifically, the seating-order determiner 71 generates the attention-destination table shown in FIG. 6 and performs initialization in the process of step S 31 shown in FIG. 8 .
[0170] In the initialization, the seating-order determiner 71 sets the “individual number” column to the numbers (H 1 to Hn in a case shown in FIG. 6 ) corresponding to conference participants attending a conference held with the teleconference system in the attention-destination table shown in FIG. 6 ; sets the “attention-destination number” column all to a number A 0 which indicates that the conference participants HM 1 to HMn who use the teleconference devices TCD 1 to TCDn pay attention to none of them; and sets the “whether registration has been made to group table” column to all “x” which indicates that registration has not yet been made to any group.
[0171] The seating-order determiner 71 generates a group table and performs initialization in the process of step S 32 as shown in FIG. 7 .
[0172] In the initialization, the seating-order determiner 71 sets the “group number” column to G 1 to Gn which indicate that each of the teleconference devices TCD 1 to TCDn forms one group, in the group table shown in FIG. 7 ; sets the “number of members” column to all 0, which indicates that none attends any group; and sets the “member” column to all null, which indicates that any group has no member.
[0173] When the seating-order determiner 71 receives attention-degree information, it starts a process to be performed when attention-degree information is generated, as shown in FIG. 9 .
[0174] In FIG. 9 , when the seating-order determiner 71 receives attention-degree information, it sets the attention-destination table according to the attention-degree information in the process of step S 41 as shown in FIG. 10 .
[0175] Actually, the seating-order determiner 71 specifies the “attention-destination number” column such that, when information (Hi:Aj) is received, which indicates that the conference participant HMi indicated by Hi pays attention to the conference participant HMj corresponding to Aj, the “attention-destination number” cell corresponding to an individual number of Hi is set to Aj.
[0176] The “whether registration has been made to group table” column is all initialized to “x.”
[0177] In a case shown in FIG. 10 , the “attention-destination number” cell corresponding to an “individual number” of H 1 is set to A 3 corresponding to the conference participant HM 3 as the attention destination of the conference participant HM 1 indicated by an “individual number” of H 1 ; the “attention-destination number” cell corresponding to an “individual number” of H 2 is set to A 0 , which indicates that none attracts attention, as the attention destination of the conference participant HM 2 indicated by an “individual number” of H 2 ; the “attention-destination number” cell corresponding to an “individual number” of H 3 is set to A 5 corresponding to the conference participant HM 3 as the attention destination of the conference participant HM 3 indicated by an “individual number” of H 3 ; and the “attention-destination number” cell corresponding to an “individual number” of H 4 is set to A 2 corresponding to the conference participant HM 2 as the attention destination of the conference participant HM 4 indicated by an “individual number” of H 4 . A description for conference participants HM 5 to HMn will be omitted. The “attention-destination numbers” column is specified for HMi in this way.
[0178] The seating-order determiner 71 sets the “numbers of members” column all to 0 and the “member” column all to null as shown in FIG. 7 in the group table in the process of step S 42 .
[0179] After steps S 42 and S 43 , the seating-order determiner 71 sets the group table according to the contents of the attention-destination table for each of “individual numbers” H 1 to Hn in the process of step S 43 .
[0180] FIG. 11 is a detailed flowchart of processing for setting the group table according to the contents of the attention-destination table in step S 43 of the flowchart of FIG. 9 . In FIG. 11 , “registration” means registration to the group table; a “self entry” means a self entry in the attention-destination table; an “attention destination” means an attention destination in a self entry; an “attention-destination entry” means the entry of an attention destination in the attention-destination table; a “self group” means a group to which the self belongs as a member; and an “attention-destination group” means a group to which an attention destination belongs as a member. An actual registration operation means that the number of members is incremented by one in a group table; a corresponding number is added as a member in the group table; and the corresponding “whether registration has been made to group table” cell in the attention-destination table is changed to “◯.”
[0181] A requirement concerning the setting of the entry of a conference participant HMi in the attention-destination table will be first described. A requirement (hereinafter called a first requirement in each teleconference device) concerning the setting of the entry of the conference participant HMi having an individual number of Hi in the attention-destination table includes the registration of the individual number Hi to the group table, and a change of the “whether registration has been made to group table” cell in the entry of the individual number Hi in the attention-destination table to “◯.” When the attention-destination number corresponding to the individual number Hi is A 0 (which means the conference participant pays attention to none of the other conference participants), only this requirement applies.
[0182] When the attention-destination number corresponding to the individual number Hi is not A 0 , a requirement (hereinafter called a second requirement in each teleconference device) includes the registration of the attention-destination number to the group table, a change of the “whether registration has been made to group table” cell in the entry of the attention destination in the attention-destination table to “◯,” and the registration of the individual number Hi and the attention destination to the same group in the group table.
[0183] By following the flowchart shown in FIG. 11 , whether these requirements are satisfied is checked.
[0184] In the process of step S 51 , the seating-order determiner 71 determines whether the “whether registration has been made to group table” cell in the self entry of the individual number Hi in the attention-destination table is “◯.” When the “registration” in the self entry has already been set to “◯” in step S 51 , since it is ensured that registration to the group table has already been performed, the first requirement is already satisfied. Therefore, when it is determined in step S 51 that YES is obtained, the seating-order determiner 71 does not perform work related to registration of the individual number Hi to the group table, and the processing proceeds to step S 53 . When it is determined in step S 51 that NO is obtained, since the “registration” is “x” in the self entry, the processing proceeds to step S 52 .
[0185] In the process of step S 52 , the seating-order determiner 71 registers the self (individual number) to a group having no member and the smallest number in the group table, and the processing proceeds to step S 53 .
[0186] As the results of steps S 51 and S 52 , the first requirement is satisfied before the process of the next step S 53 .
[0187] In the process of step S 53 , the seating-order determiner 71 determines whether the attention-destination number is not A 0 . When the attention-destination number is A 0 , in other words, it is determined in step S 53 that NO is obtained, since all requirements have already been satisfied, the seating-order determiner 71 finished the processing. When the attention-destination number is not A 0 , in other words, when it is determined in step S 53 that YES is obtained, the processing proceeds to step S 54 to satisfy the second requirement.
[0188] In the process of step S 54 , the seating-order determiner 71 determines whether the “whether registration has been made to group table” cell in the attention-destination entry is “◯.”
[0189] When the “registration” is “x” in the attention-destination entry, in other words, it is determined in step S 54 that NO is obtained, since it is sure that the attention-destination entry has not been registered to the group table, the processing proceeds to step S 58 , and the seating-order determiner 71 registers the attention destination to the group (self group) to which the self belongs, and sets the “whether registration has been made to group table” cell in the attention-destination entry in the attention-destination table to “◯.” Since the second requirement is surely satisfied with the process of step S 58 , the seating-order determiner 71 finishes the processing.
[0190] When it is determined in step S 54 that the “registration” is “◯” in the attention-destination entry, which means that the attention destination has already been registered, only the last item of the second requirement needs to be satisfied, which indicates that the individual number Hi and the attention destination belong to the same group. When it is determined in step S 54 that YES is obtained, the seating-order determiner 71 refers to the group table in the next step S 55 and checks whether the individual number Hi and the attention destination belong to the same group in step S 56 .
[0191] When it is confirmed in step S 56 that they belong to the same group, in other words, when it is determined in step S 56 that YES is obtained, since the second requirement has already been satisfied, the seating-order determiner 71 finishes the processing.
[0192] When it is determined in step S 56 that No is obtained, since the individual number Hi and the attention destination need to belong to the same group, the seating-order determiner 71 merges the two groups to which the individual number Hi and the attention destination belong in the process of step S 57 . More specifically, the seating-order determiner 71 merges (adds the number of members in the group having a larger number to that in the group having a smaller number, adds the members of the group having the larger number to those of the group having the smaller number, sets the number of members in the group having the larger number to zero, and sets the members of the group having the larger number to null) the group having a larger number into the group having a smaller number among the two groups. As a result, the second requirement is satisfied. Since all the requirements have been satisfied, the seating-order determiner 71 finishes the processing.
[0193] The confirmation of the requirements related to the settings of the entry of the conference participant HMi in the attention-destination table has been finished.
[0194] When the entry corresponding to the individual number Hi has been set in the attention-destination table, it is necessary that both the entry corresponding to the individual number Hi and those corresponding to the individual numbers up to Hi−1 be set in the attention-destination table. As for the setting of the entry corresponding to the individual number H 1 , since the other entries have not yet set so far, it is required that only the entry corresponding to the individual number H 1 be set.
[0195] Operations which may be performed when the entry corresponding to the individual number Hi is input include a new registration to the group table, the merger of two groups in the group table, and a change in the “whether registration has been made to group table” cell in the attention-destination table to “◯.” With these operations, neither numbers registered according to the entries corresponding to individual numbers up to Hi−1, followed by Hi, are deleted, nor the “whether registration has been made to group table” cells are set to “x.” In addition, two numbers belonging to the same group are not separated, either. Therefore, the process for setting the entry corresponding to the individual number Hi into the tables does not break the requirements satisfied by the processes for the individual numbers up to Hi−1, followed by Hi. Consequently, it is inductively understood that, when the processes related to the entries of all individual numbers Hi, shown in FIG. 11 , have been finished, the requirements for the entries of all individual numbers H 1 to Hi are satisfied.
[0196] Changes in the attention-destination table and in the group table, made in the processing shown by the flowchart of FIG. 11 will be described below by examples. It is assumed here that the group table has a state shown in FIG. 7 as initial states, and the attention-destination table has a state shown in FIG. 10 when group-determination information has been input. Changes in the attention-destination table and the group table will be explained.
[0197] The setting of the entry of the conference participant HM 1 (having an individual number of H 1 ) will be described first.
[0198] Since the “whether registration has been made to group table” cell is “x,” it is determined in step S 51 of FIG. 11 that NO is obtained, and the entry corresponding to the individual number Hi is input to the group table in the next step S 52 . As a result of the process of step S 52 , the “number of members” for a group number G 1 having the smallest number is set to one, and the individual number H 1 is input to the “member” column, as shown in FIG. 12 . The “whether registration has been made to group table” cell for the individual number H 1 is changed to “◯” in the attention-destination table as shown in FIG. 13 .
[0199] Then, it is determined in step S 53 that YES is obtained. Since the attention destination is A 3 indicating the conference participant HM 3 , and the “whether registration has been made to group table” cell for the entry of the individual number H 3 is “x,” as shown in FIG. 13 , it is determined in step S 54 that NO is obtained. As a result, in step S 58 , the individual number H 3 of the attention destination is input to the group G 1 , which is the “self group.” In the group table, the “number of members” in the group G 1 is set to two and its members are H 1 and H 3 in the group table as shown in FIG. 14 . In the attention-destination table, the “whether registration has been made to group table” cells for the individual numbers H 1 and H 3 are set to “◯” as shown in FIG. 15 .
[0200] The setting of the entry of the conference participant HM 1 (having an individual number of Hi) has been finished.
[0201] The setting of the entry of the conference participant HM 2 (having an individual number of H 2 ) will be described next.
[0202] Since the “whether registration has been made to group table” cell is “x” when the entry corresponding to the individual number H 2 is input to the tables, it is determined in step S 51 of FIG. 11 that NO is obtained, and the entry corresponding to the individual number H 2 is input to the group table in the next step S 52 . As a result of the process of step S 52 , the number of members for a group number G 2 having the next smallest number is set to one, and the individual number H 2 is input to the member column, as shown in FIG. 16 . The “whether registration has been made to group table” cell for the individual number H 2 is changed to “◯” in the attention-destination table as shown in FIG. 17 . Since the attention-destination number of the individual number H 2 is A 0 as shown in the case of FIG. 17 , the setting of the entry of the conference participant HM 2 has been finished at this point.
[0203] The setting of the entry of the conference participant HM 3 (having an individual number of H 3 ) will be described next.
[0204] Since the “whether registration has been made to group table” cell is “◯” as shown in FIG. 15 when the entry corresponding to the individual number H 3 is input to the tables, because the entry corresponding to the individual number H 1 has been set. Therefore, it is determined in step S 51 of FIG. 11 that YES is obtained. Since the conference participant HM 3 having the individual number H 3 pays attention to the conference participant HM 5 , it is determined in step S 53 that YES is obtained. Since the “whether registration has been made to group table” cell for the individual number H 5 , indicating the attention destination, is “x,” as shown in FIG. 17 , it is determined in step S 54 of FIG. 11 that NO is obtained.
[0205] As a result, in step S 58 , the individual number H 5 of the attention destination is input to the group G 1 , which is the “self group” of the individual number H 3 . In the group table, the number of members in the group G 1 is updated to three and its members are updated to H 1 , H 3 , and H 5 in the group table as shown in FIG. 18 . In the attention-destination table, the “whether registration has been made to group table” cell for the individual number H 5 is set to “◯” as shown in FIG. 19 .
[0206] The setting of the entry of the conference participant HM 3 (having an individual number of H 3 ) has been finished.
[0207] The setting of the entry of the conference participant HM 4 (having an individual number of H 4 ) will be described next.
[0208] Since the “whether registration has been made to group table” cell is “x” when the entry corresponding to the individual number H 4 is input to the tables, it is determined in step S 51 of FIG. 11 that NO is obtained, and the entry corresponding to the individual number H 4 is input to the group table in the next step S 52 . As a result of the process of step S 52 , the number of members for a group number G 3 which is the group following the groups G 1 and G 2 is set to one, and the individual number H 4 is input to the member column, as shown in FIG. 20 . The “whether registration has been made to group table” cell for the individual number H 4 is changed to “◯” in the attention-destination table as shown in FIG. 21 .
[0209] Then, it is determined in step S 53 that YES is obtained. Since the attention destination is A 2 indicating the conference participant HM 2 , and the “whether registration has been made to group table” cell for the entry of the individual number H 2 is “◯,” as shown in FIG. 21 , it is determined in step S 54 that YES is obtained.
[0210] In step S 55 , a group number is searched for the individual number H 2 of the attention destination to obtain the group number G 2 to which the individual number H 2 serving as the attention destination belongs. In the next step S 56 , it is determined that NO is obtained because the group number to which the individual number H 4 belongs is G 3 and the group number to which the individual number H 2 serving as the attention destination belongs is G 2 . In the next step S 57 , the group number G 3 to which the individual number H 4 belongs is merged into the group G 2 , which has a smaller number, to which the individual number H 2 belongs.
[0211] Therefore, in the group table, the number of members in the group G 2 is updated to two, and its members are updated to H 2 and H 4 , as shown in FIG. 22 . The attention-destination table is updated (the same as that shown in FIG. 21 ) as shown in FIG. 23 .
[0212] The setting of the entry of the conference participant HM 4 (having an individual number of H 4 ) has been finished.
[0213] The setting of the entry of the conference participant HM 5 (having an individual number of H 5 ) will be described last.
[0214] Since the “whether registration has been made to group table” cell is “◯” as shown in FIG. 23 when the entry corresponding to the individual number H 5 is input to the tables. Therefore, it is determined in step S 51 of FIG. 11 that YES is obtained. Since the conference participant HM 5 having the individual number H 5 pays attention to the conference participant HM 3 , it is determined in step S 53 that YES is obtained. Since the “whether registration has been made to group table” cell for the individual number H 3 , indicating the attention destination, is “◯” as shown in FIG. 23 , it is determined in step S 54 of FIG. 11 that YES is obtained.
[0215] In step S 55 , a group number is searched for the individual number H 3 of the attention destination to obtain the group number G 1 to which the individual number H 3 serving as the attention destination belongs. In the next step S 56 , it is determined that YES is obtained because the group number to which the individual number H 3 serving as the attention destination belongs is G 1 , and the individual number H 5 has already been registered to the group G 1 . The processing is finished.
[0216] The group table is updated (is the same as that shown in FIG. 22 ) as shown in FIG. 24 , and the attention-destination table is updated (is the same as that shown in FIG. 23 ) as shown in FIG. 25 .
[0217] With the processing described above, when information related to all individual numbers are input to the attention-destination table, the “registration to group table” column is set to all “◯” in the attention-destination table. All individual numbers have already been registered to any one of groups as members in the group table.
[0218] 5. Seating-Order Determination Operation Through Grouping in the Seating-Order Determination Device
[0219] When group determination is finished in the processing described above, the seating-order determination device GJD determines a seating order such that persons belonging to the same group are collectively arranged.
[0220] To this end, the seating-order determination device GJD holds seating-order information as well as group information.
[0221] When a group is changed, the seating-order determination device GJD refers to the held seating-order information and changes it by processing shown in a flowchart of FIG. 26 to determine a new seating order. This processing will be described below.
[0222] In step S 101 , it is determined whether there is a group (hereinafter called a divided group) in which its members are separated.
[0223] When no group is divided at the seating order used before a change, in other words, when members are collectively arranged in all groups, since the target condition is satisfied, the seating order used before a change is used as is. The processing shown in FIG. 26 is finished.
[0224] When it is determined in step S 101 that there is a divided group, a group having the largest number of members is determined among divided groups in step S 102 . When there are a plurality of divided groups, a group having the minimum group number is regarded as the largest group. Since the largest group is divided, if a set of one person or more collectively arranged is called a sub group, the largest group is formed of a plurality of sub groups.
[0225] When the largest divided group is determined, the largest sub group is determined in the largest divided group and a sub group located closest to the largest sub group is determined in step S 103 . When there are a plurality of groups having the largest number of members among sub groups, a group to which a person having the minimum individual number belongs is regarded, for example, as the largest sub group. When separate sub groups are located at the same distance from the largest sub group clockwise and counterclockwise, the sub group located at the distance counterclockwise is regarded, for example, as the sub group closest to the largest group.
[0226] When the sub group closest to the largest sub group is determined, the determined sub group is connected to the largest sub group in step S 104 . This connection process will be described below.
[0227] The determined sub group closest to the largest sub group counterclockwise from the largest sub group is shifted clockwise to connect to the largest sub group. The determined sub group closest to the largest sub group clockwise from the largest sub group is shifted counterclockwise to connect to the largest sub group. When the determined sub group is located at the same distance from the largest sub group clockwise and counterclockwise, the determined sub group is, for example, shifted clockwise to connect to the largest sub group. Persons located between the largest sub group and the sub group closest thereto are shifted by the number of members belonging to the sub group closest to the largest sub group in the direction opposite that in which the sub group closest to the largest sub group is shifted.
[0228] Details of the connection process have been described.
[0229] Since the number of sub groups in the largest divided group is reduced by one by the above-described connection process, the largest divided group is collectively arranged by the repetition of the process shown in the flowchart of FIG. 26 .
[0230] When the process for one divided group is finished, the same process can be applied to the next largest group by the repetition of the process shown in the flowchart. Therefore, each of all groups is collectively arranged by the repetitions of the process shown in the flowchart, and the seating-order determination processing is finished with the target condition being obtained.
[0231] Two example seating-order changes in the seating-order determination processing will be described below.
[0232] FIG. 27 shows a first example. In a state shown in FIG. 27( a ), only a group G 1 indicated by black circles is divided into sub groups SG 1 and SG 2 . The sub group SG 2 closest to the largest sub group SG 1 is located in the counterclockwise direction.
[0233] In this case, the connection process performs shifting indicated by arrows in FIG. 27( a ) to change a seating order to that shown in FIG. 27( b ), and the seating-order determination processing is completed.
[0234] FIG. 28 shows a second example. In a state shown in FIG. 28( a ), two groups, a group G 1 indicated by black circles and a group G 2 indicated by white circles, are divided. The largest divided group is the group G 1 . The group G 1 is divided into three sub groups SG 1 , SG 2 , and SG 3 . The sub groups SG 2 and SG 3 are located at the same distance from the largest sub group SG 1 clockwise and counterclockwise. In this case, according to the above-described rule, shifting is performed first so as to connect the sub group SG 3 , located in the counterclockwise direction from the largest sub group.
[0235] Then, as shown in FIG. 28( b ), two sub groups SG 11 and SG 2 are disposed. The sub group closest to the largest sub group SG 11 is SG 2 , and located in the clockwise direction from the largest sub group SG 11 .
[0236] The connection process is applied to the sub group SG 2 to obtain a state shown in FIG. 28( c ), in which the group G 1 is collectively arranged.
[0237] As a result of the process, another divided group G 2 is collectively arranged. A total to two repetitions of the connection process completes the seating-order determination processing.
[0238] When the seating-order determination processing is completed as described above, for example, the seating-order determiner 71 generates seating-order information showing the determined seating order and sends it to each teleconference device TCD. Together with the seating-order information, the seating-order determiner 71 sends group information indicating the state of grouping.
[0239] In the above-described case, the seating-order determiner 71 determines the seating order according to the result of group determination such that conference participants belonging to the same groups are collectively arranged. To make a viewing range small when watching members belonging to the same group, members belonging to the same groups may be arranged so as to be uniformly dispersed.
[0240] As shown in FIG. 29 , for example, a seating order may be determined such that conference participants belonging to groups G 1 and G 2 are uniformly dispersed.
[0241] 6. Seating-Order Changing Processing Performed According to Seating-Order Information in a Teleconference Device
[0242] Operations of a teleconference device TCD, performed when image data and audio data sent from each teleconference device TCD, and the above-described seating-order information sent from the seating-order determination device GJD are received in the teleconference system according to the present embodiment will be described below. The teleconference device TCD 1 will be taken as an example among the teleconference devices TCD 1 to TCDn and its operations will be described.
[0243] When the information transmitting and receiving section TRB 1 of the teleconference device TCD 1 receives a signal sent through the communication network NT, the information transmitting and receiving section TRB 1 separates the image data and the audio data corresponding to the teleconference devices TCD 2 to TCDn from the signal; picks up the above-described seating-order information (including the group information); and sends the picked-up seating-order information as well as the separated image data and audio data to the information manipulation and distribution section PB 1 .
[0244] The information manipulation and distribution section PB 1 distributes input images and/or sound to the corresponding monitor devices MD according to the seating-order information. The information manipulation and distribution section PB 1 may manipulate images and/or sound to be distributed, so that, for example, a seating-order change is made easy to understand intuitively.
[0245] A specific process to be performed in the information manipulation and distribution section PB 1 will be described below by taking a case as an example, in which manipulation is applied to images and sound so as to make a seating-order change easy to understand intuitively, and images and sound are sent to the corresponding monitor devices MD according to the seating-order information.
[0246] FIG. 30 shows the structure of the information manipulation and distribution section PB 1 . It includes an input terminal 201 for receiving images and sound received by the information transmitting and receiving section TRB 1 shown in FIG. 2 ; an input terminal 202 for receiving seating-order information received by the information transmitting and receiving section TRB 1 ; a motion determination section 203 for performing motion determination related to the seating-order information; a connection determination section 204 for determining a connection state according to the seating-order information; an image manipulation device 205 and an audio manipulation device 206 for manipulating input images and sound; and an information distribution section 207 for distributing manipulated images and sound to each monitor device MD.
[0247] The output terminals TO 2 to TOn connected to the information distribution section 207 are those used for sending images and sound to the monitor devices MD 2 to MDn as shown in FIG. 2 .
[0248] The motion determination section 203 determines the directions and amounts of the relative motions of conference participants HM located at remote places against the conference participant HM 1 located on site according to the input seating-order information, namely, determines the directions and amounts of motions related to changes in a seating order, and sends the results as motion information to the image manipulation section 205 and to the audio manipulation section 206 .
[0249] FIG. 31 shows the structure of the image manipulation device 205 . The image manipulation device 205 includes image manipulators 250 - 2 , 250 - 3 , . . . , and 250 - n for manipulating the input images corresponding to conference participants HM.
[0250] The images of conference participants HM are sent from an input terminal 251 to the image manipulators 250 - 2 , 250 - 3 , . . . , and 250 - n , and the motion information is sent from the motion determination section 203 through an input terminal 252 to the image manipulators 250 - 2 , 250 - 3 , and 250 - n.
[0251] Each of the image manipulators 250 - 2 , 250 - 3 , . . . , and 250 - n extracts a motion related to the corresponding conference participant HM from the motion information, and manipulates the input image of the corresponding conference participant HM that the movement of the conference participant HM is intuitively easy to understand, as required, according to the extracted motion.
[0252] The manipulated images are output from an output terminal 253 to the information distribution section 207 .
[0253] In an example manipulation performed in each of the image manipulators 250 - 2 , 250 - 3 , . . . , and 250 - n , arrows indicating the directions of the relative motions of conference participants HM located at remote places against the conference participant HM 1 located on site are superposed on input images.
[0254] FIG. 34 ( a ) shows an input image, and FIG. 34( b ) shows a manipulated image obtained when a motion direction is left.
[0255] When a relative motion is not found, a method in which an arrow is not superposed may be used. An arrow is superposed until the time immediately before a connection is changed by the information distribution section 207 , described later.
[0256] In another example manipulation performed in each of the image manipulators 250 - 2 , 250 - 3 , . . . , and 250 - n , input images are moved on screens in the directions of the relative motions of conference participants HM located at remote places against the conference participant HM 1 located on site.
[0257] FIG. 35( a ) shows an input image, and FIG. 35( b ), ( c ), and ( d ) shows manipulated images obtained every time when a predetermined time elapses, if the motion direction is left. Input images are moved until the time immediately before a connection is changed by the information distribution section 207 .
[0258] In still another example manipulation performed in each of the image manipulators 250 - 2 , 250 - 3 , . . . , and 250 - n , input images are moved on screens as described above with the background being fixed and only the portion of the conference participants HM in the input images being moved.
[0259] To implement the above-described manipulation, there is a method in which backgrounds viewed from the cameras corresponding to conference participants HM located at remote places are set to blue backgrounds (BB); portions other than the blue backgrounds are extracted as conference participants from input images by the image manipulators 250 - 2 , 250 - 3 , . . . , and 250 - n ; the portions are shifted according to the corresponding motions and then attached back to the images; and a fixed background is attached to the parts other than the portions attached in the images.
[0260] FIG. 36( a ) shows an example input image, obtained before movement, FIG. 36( b ) shows a manipulated image obtained when a predetermined time elapses, and FIG. 36( c ) shows a manipulated image obtained when a predetermined time further elapses, if a motion direction is left. As shown in the figure, the image of the conference participant is shifted, for example, in the left direction according to the direction in which a seating order is changed with a blue background (BB) being used as a background. The image is shifted according to the corresponding motion, for example, until the time immediately before a connection is changed by the information distribution section 207 , described later.
[0261] When the seating order of conference participants displayed on the monitor devices MD 2 to MDn is changed, these image manipulation processes make the change and a direction in which the change is performed easy to understand for the conference participant HM 1 .
[0262] FIG. 32 shows the structure of the audio manipulation device 206 . The audio manipulation device 206 includes audio manipulators 260 - 2 , 260 - 3 , . . . , and 260 - n for manipulating the input sound corresponding to conference participants HM.
[0263] The sound of conference participants HM are sent from an input terminal 261 to the audio manipulators 260 - 2 , 260 - 3 , . . . , and 260 - n , and the motion information is sent from the motion determination section 203 through an input terminal 262 to the image manipulators 260 - 2 , 260 - 3 , and 260 - n.
[0264] Each of the audio manipulators 260 - 2 , 260 - 3 , . . . , and 260 - n extracts a motion related to the corresponding conference participant HM from the motion information, and manipulates the input sound of the corresponding conference participant HM so that the movement of the conference participant HM is intuitively easy to understand, as required, according to the extracted motion.
[0265] The manipulated sound is output from an output terminal 263 to the information distribution section 207 .
[0266] In an example manipulation performed in each of the audio manipulators 260 - 2 , 260 - 3 , . . . , and 260 - n , a message such as “the seating order is being changed” and/or sound indicating a change of the seating order is superposed on sound when a conference participant HM located at a remote place relatively moves against the conference participant HM 1 located on site. The message and/or sound is superposed, for example, until the time immediately before or immediately after a connection is changed by the information distribution section 207 , described later.
[0267] In another example manipulation, a message such as “the seating order is being changed” and/or sound indicating a change of the seating order is superposed on sound irrespective of the motion of a conference participant HM located at a remote place. The message and/or sound is superposed, for example, until the time immediately before or immediately after a connection is changed by the information distribution section 207 , described later.
[0268] The connection determination section 204 , shown in FIG. 30 , determines a method for connecting images and sound to each monitor device MD according to the seating order information input from the input terminal 202 , and sends it to the information distribution section 207 as connection information.
[0269] FIG. 33 shows the structure of the information distribution section 207 . Images sent from the image manipulation device 205 through an input terminal 271 , and sound input from the sound manipulation device 206 through an input terminal 272 are sent to a matrix switcher 270 . The images and sound are sent to each monitor device MD so as to conform to the seating-order information, according to the connection information sent from the connection determination section 204 through an input terminal 273 to the matrix switcher 270 . In other words, the matrix switcher 270 switches the images and sound to the output terminals TO 2 to TOn according to the connection information.
[0270] Since the information manipulation and distribution section PB has the above-described structure in the signal processing device SPD of each teleconference device TCD, a dynamic seating-order change is performed in the monitor devices MD 2 to MDn according to the seating-order information generated by the seating-order determination device GJD.
[0271] The relationships (seating order) between the monitor devices MD 2 to MDn and conference participants HM 2 to HMn shown thereon are flexibly changed according to conversation groups made and released during a conference such that a suitable condition is made for the conference participant HM 1 to do conversation.
[0272] In the foregoing description, both images and sound are handled as information related to conference participants HM located at remote places. One of them may be handled as the information.
[0273] In the foregoing description, images and sound are manipulated. Input images and/or sound may be directly sent to the information distribution section 207 without being manipulated.
[0274] When a seating-order is frequently changed, a confusion may occur as to which conversation each conference participant is doing.
[0275] To avoid such a condition, when the seating-order determination device GJD determines a seating order according to group determination as described above, a process for making the background of each conference participant HM in the corresponding image have similarity in units of groups can be applied in image processing performed by the information manipulation and distribution section PB.
[0276] More specifically, for example, backgrounds viewed from the cameras corresponding to conference participants HM located at remote places are set to blue backgrounds; the information manipulation and distribution section PB extracts these blue backgrounds as backgrounds; and changes them to backgrounds having the same colors in units of groups. The information manipulation and distribution section PB sets the background color of each image and performs image processing according to the group information. A method for setting the backgrounds of conference participants who belong to the same group as the self (conference participant HM 1 ) to, for example, a fixed color (such as blue) can be considered so as to understand the conference participants belonging to the same group as the conference participant HM 1 .
[0277] FIG. 37A and FIG. 37B show example background colors used before and after conversion. In the figure, G 1 to G 3 indicate the numbers of groups to which conference participants belong. In this case, in a state obtained after the conversion shown in FIG. 37B , the conference participants belonging to the group G 2 understand that the conference participant having the blue background belongs to the same group, and easily understands that the group G 1 having a red background and the group G 3 having a green background are formed.
[0278] 7. First Example of Grouping Processing which Uses a Statistical Relationship, in the Seating-Order Determination Device
[0279] In the foregoing case, the seating-order determination device GJD uses a group determination method based on the rule in which a link is made between a person who pays attention to another person and the another person, who attracts attention, and one group is formed of persons who are coupled directly or indirectly by links. In another case, a group can be determined by statistical relationships between attention patterns which indicate combinations of the attention destinations of conference participants, and group patterns.
[0280] In such a case, a process can be used in which the seating-order determination device GJD prepares a group determination table like that shown in FIG. 40 , and converts an attention pattern to a group pattern according to the table.
[0281] A method for preparing such a group determination table in advance according to statistics will be described below. A case in which the number of conference participants is three will be taken as an example.
[0282] To make a group determination table, an experiment is performed to have actual conversation states, and time-sequential samples formed of combinations of attention patterns and group patterns are prepared, for example, at a predetermined interval.
[0283] It is possible, for example, that attention patterns are automatically obtained and group patterns are determined by a person.
[0284] Two methods for generating a group determination table according to the samples can be considered. A first method will be described first.
[0285] In this method, the most frequently generated group pattern is found for each attention pattern, and the group pattern is registered as the group pattern corresponding to the attention pattern.
[0286] An experiment is first performed in this method to record a pattern of the attention destinations of conference participants and a group pattern formed at that time at a predetermined interval to generate a frequency table between attention patterns and group patterns, like that shown in FIG. 39 .
[0287] In FIG. 39 , numbers (zero indicates that a conference participant pays attention to nobody) indicated below conference participants HM 1 to HM 3 are those of the attention destinations of the conference participants, and GP 1 to GP 5 indicate the numbers of group patterns.
[0288] FIG. 38 shows example definitions of group patterns.
[0289] Various group forms are defined as group patterns GP 1 to GP 5 as shown in FIG. 38 , in which a group pattern GP 1 indicates that three conference participants HM 1 to HM 3 have no group, a group pattern GP 2 indicates a state in which conference participants HM 1 and HM 2 form a group, . . . .
[0290] The frequency table shown in FIG. 39 indicates that, as a result of the experiment, when the attention destinations of the conference participants HM 1 to HM 3 are all zero, the group pattern GP 1 is formed 10034 times, the group pattern GP 2 is formed 130 times, . . . , and the group pattern GP 5 is formed 3024 times.
[0291] A group pattern is determined in the experiment, for example, by a person who sees the state.
[0292] According to such a frequency table, the group pattern corresponding to an attention pattern of the conference participants HM 1 to HM 3 is selected so as to have the highest probability, and the group determination table shown in FIG. 40 is made from the selected correspondences.
[0293] In the frequency table shown in FIG. 39 , when the attention destinations of the conference participants HM 1 to HM 3 are all zero, the group pattern GP 1 has the highest frequency. Therefore, when the conference participants HM 1 to HM 3 have an attention destination of 0, which is shown by (0, 0, 0), the group pattern is set to GP 1 .
[0294] When the conference participant HM 3 has an attention destination of 1 and the other conference participants HM 1 and HM 2 have an attention destination of 0, which is shown by (0, 0, 1), the group pattern is set to GP 4 according to the frequency table shown in FIG. 39 .
[0295] A group pattern having the highest frequency is determined for each of all attention-destination patterns to make the relationships between attention-destination patterns and group patterns shown in FIG. 40 .
[0296] The seating-order determination device GJD holds a group determination table generated in advance, like that described above, to determine the group corresponding to an attention pattern of the conference participants HM 1 to HM 3 by referring to the group determination table when it receives attention-degree information from the teleconference devices TCD, and generates seating-order information according to the group determination.
[0297] 8. Second Example of Grouping Processing which Uses a Statistical Relationship, in the Seating-Order Determination Device
[0298] In the foregoing case, all attention patterns are independently handled when the frequency table between attention patterns and group patters is generated. In a second case, attention patterns similar to each other are collectively handled to generate a frequency table, and a group determination table is formed according the frequency table.
[0299] When attention-destination patterns of the conference participants HM 1 to HM 3 are (0, 0, 2), (0, 1, 0), (0, 3, 0), (2, 0, 0), and (3, 0, 0), for example, their mutual attention-destination relationships are substantially the same as attention destinations obtained by rotating and/or inverting those of (0, 0, 1). Therefore, for example, the group patterns GP 1 , GP 2 , GP 3 , GP 4 , and GP 5 corresponding to an attention pattern of (0, 0, 2) are regarded as the same as the group patterns GP 1 , GP 2 , GP 3 , GP 4 , and GP 5 corresponding to an attention pattern of (0, 0, 1), obtained by inverting (applying inversion for a segment drawn from the conference participant HM 3 to the middle of the conference participants HM 1 and HM 2 to) the group patterns of the attention pattern of (0, 0, 2), similar attention patterns are collectively handled as an attention pattern of (0, 0, 1), and then statistics is obtained.
[0300] In this case, when an attention pattern of (0, 0, 1) corresponds to determination group patterns GP 1 , GP 2 , GP 3 , GP 4 , and GP 5 in a group determination table, an attention pattern of (0, 0, 2) corresponds to the determination group patterns GP 1 GP 2 , GP 3 , GP 4 , and GP 5 .
[0301] In other words, in the second case, each set of attention patterns which are made the same by rotation or inversion is represented by a representative attention pattern, statistics is obtained for representative attention patterns, a group-pattern determination table is generated from the statistics for the representative attention patterns, and finally, a group determination table is generated for all attention patterns.
[0302] With the use of such a method, it is expected that individuality is avoided and highly reliable determination is made with a relatively small number of samples.
[0303] A detailed procedure for generating a group determination table in the second case will be described below.
[0304] Prior to the generation of a group determination table based on statistics, a conversion table for converting actual attention patterns and actual group patterns to representative attention patterns and representative group patterns is generated in advance.
[0305] In the same way as in the first case, a condition in which the number of conference participants is three is taken as an example. An attention-pattern conversion table shown in FIG. 41 , a group conversion table shown in FIG. 42 , and a group inverted-conversion table shown in FIG. 45 need to be prepared in advance.
[0306] The attention-pattern conversion table shown in FIG. 41 shows which representative pattern serves as a representative of an attention pattern, and which conversion method is used for converting an attention pattern to a representative attention pattern.
[0307] As a representative attention pattern, an attention pattern having the smallest number is selected when the attention-destination numbers of the conference participants HM 1 , HM 2 , and HM 3 are regarded as a third digit, a second digit, and a first digit, respectively, to form a decimal number.
[0308] Conversions are expressed by whether inversion is performed and the number of rotations under a rule in which inversion is performed first and then rotation is performed.
[0309] FIG. 46A and FIG. 46B show the axis of inversion and the direction of rotation. Examples of inversion and rotation are shown in FIG. 46A and FIG. 46B .
[0310] In the attention-pattern conversion table shown in FIG. 41 , whether inversion is performed is indicated by “0,” which shows no inversion, and “1,” which shows that inversion is performed.
[0311] The number of rotations means the number of rotations performed in the direction shown in FIG. 46B .
[0312] The group conversion table shown in FIG. 42 indicates that each group pattern is converted to which group pattern when the above-described inversion and rotation are performed.
[0313] More specifically, group patterns obtained when neither inversion nor rotation is applied to each group pattern, when rotation is applied once, when rotation is applied twice, when only inversion is applied, when inversion is applied and then rotation is applied once, and when inversion is applied and then rotation is applied twice are shown in the table.
[0314] When attention patterns in samples are converted to representative attention patterns, this table is used for obtaining group patterns corresponding to group patterns in samples which match the conversion. Details will be described later.
[0315] The group-pattern inverted-conversion table shown in FIG. 45 indicates a group pattern obtained when the inverted conversion of a specified conversion is applied to each group pattern, and is used for generating the group determination table shown in FIG. 40 from a representative-group determination table shown in FIG. 44 , described later.
[0316] A device structure and a generation procedure for generating the group determination table shown in FIG. 40 from these tables will be described next.
[0317] FIG. 47 shows functional blocks of a device for generating the group determination table shown in FIG. 40 .
[0318] Each block can be implemented by either software or hardware. A group-determination-table generating device having the functional blocks shown in FIG. 47 may be built, for example, in the seating-order determination device GJD, or may be implemented, for example, by a personal computer which is a separate device from the seating-order determination device GJD. In either case, when the seating-order determination device GJD is finally made to hold a generated group determination table, if it receives attention-degree information from the teleconference devices TCD, it determines the group corresponding to an attention pattern of the conference participants HM 1 to HM 3 by referring to the group determination table and generates seating-order information according to the group determination.
[0319] The group-determination-table generating device includes, as shown in FIG. 47 , information obtaining means 301 , information conversion means 302 , representative-frequency-table generating means 303 , representative-group-determination-table generating means 304 , representative-group determination means 305 , group inverted-conversion means 306 , and group-determination-table generating means 307 .
[0320] The information obtaining means 301 obtains attention patterns and group patterns as samples obtained in an experiment.
[0321] The information conversion means 302 uses the pattern conversion table shown in FIG. 41 and the group conversion table shown in FIG. 42 to convert the attention patterns and the group patterns obtained by the information obtaining means 301 .
[0322] The representative-frequency-table generating means 303 generates a representative frequency table like that shown in FIG. 43 according to representative attention patterns and representative group patterns.
[0323] The representative-group-determination-table generating means 304 generates a representative group determination table like that shown in FIG. 44 according to the representative frequency table.
[0324] The representative-group determination means 305 searches the representative-group determination table shown in FIG. 44 to determine the representative group pattern corresponding to a representative attention pattern.
[0325] The group inverted-conversion means 306 inverted-converts representative group patterns to group patterns.
[0326] The group-determination-table generating means 307 generates the group determination table shown in FIG. 40 from group patterns and attention patterns.
[0327] In FIG. 47 , solid lines with arrows indicate a flow of generating the representative-group determination table shown in FIG. 44 , and dotted lines with arrows indicate a flow of generating the group determination table shown in FIG. 40 from the representative-group determination table.
[0328] The group-determination-table generating device having such a structure first generates a representative frequency table such as that shown in FIG. 43 .
[0329] All attention patterns and group patterns in samples are first converted to representative attention patterns and to group patterns (hereinafter, for convenience, called representative group patterns) to which conversion matching the conversion from the attention patterns to the representative attention patterns is applied, and the frequencies of the representative group patterns for each representative attention pattern are indicated in a representative frequency table.
[0330] FIG. 48 shows processing for generating the representative frequency table.
[0331] In FIG. 48 , “registration to representative frequency table” means that the frequency of a representative attention pattern and a corresponding representative group pattern is incremented by one.
[0332] In step S 110 , the information obtaining means 301 obtains a first sample of an attention pattern and a group pattern. Then, in the next step S 111 , the information conversion means 302 uses the attention-pattern conversion table to search for the representative attention pattern corresponding to the attention pattern obtained as the sample and a conversion method to the representative attention pattern.
[0333] In the next step S 112 , the information conversion means 302 uses the group conversion table shown in FIG. 42 to convert the group pattern to a representative group pattern according to the conversion method searched for in step S 111 .
[0334] With these steps S 111 and S 112 , the representative attention pattern and the representative group pattern are obtained for the one obtained sample.
[0335] In the next step S 113 , the representative-frequency-table generating means 303 registers the obtained representative attention pattern and the obtained representative group pattern into the representative frequency table shown in FIG. 43 . In other words, the cell corresponding to the current sample is incremented by one.
[0336] In step S 114 , it is determined whether the processing has been finished for all samples. When the processing has not yet been finished, the information obtaining means 301 obtains the next sample of an attention pattern and a group pattern in step S 115 , the processing returns to step S 111 , and the same processes as described above are performed.
[0337] Therefore, when the processes of steps S 111 , S 112 , and S 113 have been finished for all samples, the representative frequency table shown in FIG. 43 has been completed.
[0338] Next, the representative-group determination table shown in FIG. 44 is generated from the representative frequency table generated as described above.
[0339] The representative-group determination table indicates the representative group pattern corresponding to each representative attention pattern. A representative attention pattern in each entry (row) is the same as that shown in the representative frequency table.
[0340] The representative-group determination table is generated by registering, as the representative group pattern corresponding to each representative attention pattern, the representative group pattern having the highest frequency for each representative attention pattern among representative group patterns. FIG. 49 shows the specific procedure of generating the table.
[0341] The representative-group-determination-table generating means 304 obtains a first entry of the representative frequency table generated by the representative-frequency-table generating means 303 in step S 120 . In step S 121 , the representative-group-determination-table generating means 304 determines the representative-group pattern having the highest frequency for the representative attention group in the obtained entry, and registers it to the representative-group determination table.
[0342] In the representative frequency table shown in FIG. 43 , for example, the frequencies of representative group patterns are indicated for a representative attention pattern of (0, 0, 0) in a first entry. The representative group pattern GP 1 has the highest frequency. Therefore, as shown in a first row of the representative-group determination table shown in FIG. 44 , the representative group pattern GP 1 is registered correspondingly to a representative attention pattern of (0, 0, 0).
[0343] In step S 122 , it is determined whether the processing has been finished for all entries in the representative frequency table. When the processing has not yet been finished, the next entry is obtained in step S 123 and the processing returns to step S 121 .
[0344] When the process of step S 121 is finished for all entries, the processing is finished at step S 122 .
[0345] With the above-described processing, the representative-group determination table shown in FIG. 44 is generated from the representative frequency table shown in FIG. 43 . The processing performed so far corresponds to the flow indicated by the solid lines in FIG. 47 .
[0346] The group determination table shown in FIG. 40 is finally generated from the representative frequency table.
[0347] The group determination table includes all attention patterns. To generate the group determination table, the group pattern having the “relationship between the representative attention pattern and the representative group pattern registered therefor” corresponding to each attention pattern in the representative-group determination table, which relationship matches the “relationship between the attention pattern and the group pattern registered therefor,” is registered.
[0348] FIG. 50 shows a specific procedure for generating the group determination table. (The procedure corresponds to the flow indicated by the dotted lines in FIG. 47 ).
[0349] After the representative-group determination table is generated as described above, in step S 130 shown in FIG. 50 , the information obtaining means 301 obtains a first attention pattern. In step S 131 , the information conversion means 302 uses the attention-pattern conversion table to search for a representative attention group and a conversion method to the representative attention pattern for the obtained attention pattern. The result of searching is passed to the representative-pattern determination means 305 .
[0350] In the next step S 132 , the representative-group determination means 305 uses the representative-group determination table to search for the representative group pattern corresponding to the representative attention pattern passed from the information conversion means 302 . The result of searching is passed to the group inverted-conversion means 306 as the representative group pattern.
[0351] In step S 133 , the group inverted-conversion means 306 uses the group inverted-conversion table shown in FIG. 43 to inverted-converts the representative group pattern passed from the representative-group determination means 305 to a group pattern.
[0352] In step S 134 , the group-determination-table generating means 307 registers an entry formed of the attention pattern obtained by the information obtaining means 301 as described above, and the group pattern sent from the group inverted-conversion means 306 into the group determination table.
[0353] In step S 135 , it is determined whether the processing has been finished for all attention patterns. When the processing has not yet been finished, the next attention pattern is obtained in step S 136 , and the processing returns to step S 131 .
[0354] When registration has been made to the group determination table for all attention patterns, the processing is finished at step S 135 .
[0355] With the above-described processing, the group determination table shown in FIG. 40 is generated.
[0356] A group determination table used for group determination is generated as described above. The seating-order determination device GJD performs grouping with the use of a group determination table to generate seating-order information.
[0357] 9. Seating-Order Determination Operation not Through Grouping in the Seating-Order Determination Device
[0358] So far, a case has been described in which the seating-order determination device GJD first performs group determination and then determines a seating order according to the result of group determination. A seating order can be determined without performing group determination. An example case will be described below.
[0359] The seating-order determination device GJD holds an information request degree Rij indicating a degree at which each conference participant HMi wants the information of another conference participant HMj. It is considered, for example, that the information request degree is high for an attention destination at a point of time close to the current time. When a conference participant HMi paid attention to conference participants HM 2 and HM 5 in the past and currently pays attention a conference participant HM 3 , for example, the information request degrees of the conference participant HMi for these conference participants are set to areas Ri 2 , Ri 5 , and Ri 3 located under a curve shown in FIG. 52 . The curve shown in the figure is based on an exponential function for a constant K larger than zero and smaller than one.
[0360] More specifically, the seating-order determination device GJD checks whether each conference participant HMi pays attention to another conference participant HMj at a constant interval, and sets a variable Aij indicating whether attention is paid to “1” when the conference participant HMi pays attention to the conference participant HMj, and sets it to “0” when the conference participant HMi does not pay attention to the conference participant HMj.
[0361] When attention checking is finished, the seating-order determination device GJD calculates the information request degree of the conference participant HMi for the conference participant HMj at a time “It” by the following expression (1).
[0000] Rij ( t )= KRij ( t− 1)+ Aij ( t ) (1)
[0000] where, K is an attenuating coefficient.
[0362] Then, the seating-order determination device GJD calculates an overall satisfaction degree Sm of the entire conference participants for each of all possible seating-order candidates (seating-order number m). The following expression (2) is used.
[0000]
S
m
=
∑
i
∑
j
Wmij
·
Rij
(
2
)
[0000] where, Wmij is a satisfaction-degree weighting coefficient determined in advance for each information request degree in each seating order, and held, for example, in a satisfaction-degree weighting table shown in FIG. 51 .
[0363] The table shown in FIG. 51 shows a case in which the number of conference participants is six. Characters A to F correspond to seat numbers, and numerals 1 to 6 shown therebelow correspond to conference participants HM 1 to HM 6 .
[0364] Since the relative positional relationships among conference participants are meaningful in a seating order, when it is specified, for example, that a conference participant HM 1 is always assigned to a seat A, the number of seating orders is equal to the number of the permutations of five things, which is 120, and a seating-order number ranges from 1 to 120.
[0365] FIG. 53 shows an example arrangement of seats A to F.
[0366] The satisfaction-degree weight Wmij shown in FIG. 51 is set, for example, larger when the distance between HMi and HMj is closer in a seating order “m.” More specifically, for example, the reciprocal 1/Dij — 1 of the number Dij — 1 indicating that HMj is located at the Dij — 1-th position from HMi, or the reciprocal l/Dij — 2 of a number Dij — 2 indicating the distance between HMi and HMj when the distance between adjacent seats is set to “1” can be used as the satisfaction-degree weight.
[0367] In a seating order shown in FIG. 54 , D 16 — 1 is 2, and D 16 _ 2 is √{square root over (3)}.
[0368] The seating-order determination device GJD determines the seating order corresponding to the maximum satisfaction degree Sm as a result of calculation. When there is a plurality of the maximum satisfaction degrees Sm, the seating order which makes the sum of the distances of movements required for the other conference participants, viewed from each conference participant smallest, or the seating order which has the smallest seating-order number can be selected.
[0369] 10. Attention-Degree-Information Generating Operation in a Teleconference Device
[0370] Various operations for dynamically changing a seating order according to the attention degrees of conference participants have been described. A specific processing for detecting a direction (direction toward any of the monitor devices MD 2 to MDn or another direction) in which a conference participant HM 1 pays attention, according to image data sent, for example, from the camera of the monitor device MDm disposed at the front of the conference participant HM 1 in the attention-degree-information generating section JB 1 shown in FIG. 2 will be described.
[0371] As a first example of the processing for detecting a direction in which the conference participant HM 1 pays attention, to be performed in the attention-degree-information generating section JB 1 of the teleconference device TCD 1 according to the present embodiment, the detection (sight-line detection) of the lines of sight of the conference participant HM 1 can be taken.
[0372] FIG. 55 is a flowchart of sight-line detection processing in the attention-degree-information generating section JB 1 .
[0373] In FIG. 55 , the attention-degree-information generating section JB 1 receives image data captured by the camera provided, for example, for the monitor device MDm disposed at the front of the conference participant HM 1 in step S 11 . In the next step S 12 , the attention-degree-information generating section JB 1 uses the color information of the sent image to detect the outlines of both eyes of the conference participant HM 1 in a facial image. More specifically, the attention-degree-information generating section JB 1 extracts color areas, such as skin, whites, and irises, by using the color information of the sent image, and obtains, for example, the boundaries of the extracted color areas to detect the outline E of the right eye and that of the left eye as shown in FIG. 56 . FIG. 56 indicates only one eye.
[0374] Then, in step S 13 , the attention-degree-information generating section JB 1 obtains the positions of the leftmost point F 1 and the rightmost point F 2 of the right eye and those of the left eye according to the outlines E of both eyes obtained in step S 12 , determines a search area NE for searching for the nostrils, as shown in FIG. 57 , with the positions of the rightmost and leftmost points F 2 and F 1 of the right and left eyes being used as references, and detects the positions of the nostrils NH in the search area NE. More specifically, the attention-degree-information generating section JB 1 obtains a line M which makes the center Q of gravity of the sets of pixels constituting the outlines E of the right and left eyes and the secondary moment (inertia for the line) of the sets of pixels constituting the outlines E smallest; obtains pixels one each in the right and left directions, located at the largest distances L 1 and L 2 from the center Q of gravity in the directions of line M; and obtains the pixels as the rightmost and leftmost points F 2 and F 1 , as shown in FIG. 56 .
[0375] Next, the attention-degree-information generating section JB 1 uses the positions of the rightmost and leftmost points F 2 and F 1 of the right and left eyes, obtained as described above, as references and determines the search area NE for searching for the nostrils in the lower direction from the rightmost and leftmost points F 2 and F 1 , as shown in FIG. 57 . Since the images of the nostrils NH are darker than that of the other parts, the attention-degree-information generating section JB 1 detects low-luminance image areas as the positions of the nostrils NH in the search area NE.
[0376] Then, in step S 14 , the attention-degree-information generating section JB 1 assumes the central positions ECs of the eyeballs EBs and the radius “r” of the eyeballs EBs according to the geometrical positional relationships among the positions of the rightmost and leftmost points F 2 and F 1 of the right eye, those of the rightmost and leftmost points F 2 and F 1 of the left eye, and those of the nostrils NH, as shown in FIG. 58 .
[0377] In step S 15 , the attention-degree-information generating section JB 1 uses the luminance information of the image in the outline E of the right eye and that in the outline E of the left eye to detect the central positions EAC of the pupils EA.
[0378] In step S 16 , the attention-degree-information generating section JB 1 calculate vectors EV connecting between the central positions EC of the eyeballs EB detected in step S 14 and the central positions EAC of the pupils EA detected in step S 15 , regards the obtained vectors EVs as the lines of sight, and determines the directions in which the vectors EVs are directed, namely, determines the monitor to which the vectors EVs are directed among the monitor devices MD 2 to MDn.
[0379] With the foregoing flow, the attention-degree-information generating section JB 1 detects the lines of sight of the conference participant HM 1 .
[0380] A line M which makes the secondary moment of the set of pixels, such as that of pixels constituting the outline E can be obtained, for example, by the following calculation.
[0381] A straight line M indicated by an expression (3), as shown in FIG. 60 , will be taken as an example.
[0000] x sin θ− y cos θ+ρ=0 (3)
[0382] The secondary moment for the straight line M can be indicated by an expression (4) where Ri indicates the distance between the straight line M and each point (xi, yi) of the set of pixels constituting the outline E.
[0000]
m
=
∑
i
Ri
2
=
∑
i
(
x
i
sin
θ
-
y
i
cos
θ
+
ρ
)
2
(
4
)
[0383] The straight line M which makes the secondary moment smallest is the straight line M which makes “m” in the expression (4) minimum. To make “m” in the expression (4) minimum, θ and ρ satisfying the following conditions (5) and (6) are used as those in the expression (4).
[0000] θ: sin 2θ= b /( b 2 +( a−c ) 2 ) 1/2 , cos 2 θ=( a−c )/( b 2 +( a−c ) 2 ) 1/2 (5)
[0000] ρ: ρ=− x 0 sin θ+ y 0 cos θ (6)
[0384] The expression (6) (x 0 sin θ+y 0 cos θ+ρ=0) indicates that the line passes through the center of gravity of the set of pixels.
[0385] In the expressions (5) and (6), “a,” “b,” and “c” are indicated by expressions (7), (8), and (9), respectively. (x 0 , y 0 ) indicates the coordinates of the center of gravity of the set of pixels.
[0000]
a
=
∑
i
(
x
i
-
x
0
)
2
(
7
)
b
=
2
∑
i
(
x
i
-
x
0
)
(
y
i
-
y
0
)
(
8
)
c
=
∑
i
(
y
i
-
y
0
)
2
(
9
)
[0386] As a second example of the processing for detecting a direction in which the conference participant HM 1 pays attention, to be performed in the attention-degree-information generating section JB 1 of the teleconference device TCD 1 according to the present embodiment, the detection of the face direction of the conference participant HM 1 can be taken, which will be described below.
[0387] FIG. 61 shows a flowchart of processing for detecting a face direction in the attention-degree-information generating section JB 1 .
[0388] In FIG. 61 , the attention-degree-information generating section JB 1 receives original image data, such as that shown in FIG. 62A and FIG. 62B , of the face of the conference participant HM 1 from the monitor device MDm disposed at the front of the conference participant HM 1 in step S 21 . In the next step S 22 , the attention-degree-information generating section JB 1 uses the color information of the received face images to detect a skin area and a hair area. More specifically, the attention-degree-information generating section JB 1 extracts skin-color and hair-color areas by using the color information of the received face images, and detects a skin area “se” and a hair area “he” by the extracted color areas, as shown in FIG. 63A and FIG. 63B .
[0389] In the next step S 23 , the attention-degree-information generating section JB 1 specifies frames for detecting the center “fg” of gravity of the total area “fe (=“se”+“he”)” of the skin area “se” and the hair area “he” and the center “sq” of gravity of the skin area “se,” as shown in FIG. 64A and FIG. 64B . The frames are specified, for example, by setting zones in the vertical direction in the images. More specifically, for example, the upper end “re” of the total area “fe” of the hair area “he” and the skin area “se” is used as a reference, and a zone is specified between a point a length “const_a” below the upper end “re” and a point a length “const_a”+“const_b” below the upper end “re.”
[0390] Then, in step S 24 , the attention-degree-information generating section JB 1 obtains the center “fg” of gravity of the total area “fe” of the skin area “se” and the hair area “he” and the center “sq” of gravity of the skin area “se” within the frames specified in step s 23 . In a subsequent process, both the horizontal components and vertical components of these centers of gravity can be used, or either the horizontal components or the vertical components of the centers of gravity can be used. As an example, a case in which only the horizontal components of the centers of gravity are used is taken, and will be described below.
[0391] In step S 24 , the attention-degree-information generating section JB 1 obtains the center “fg” of gravity of the total area “fe” of the skin area “se” and the hair area “he” and the center “sq” of gravity of the skin area “se.” In step S 25 , the attention-degree-information generating section JB 1 calculates the difference obtained by subtracting the center “fg” of gravity of the total area “fe” of the skin area “se” and the hair area “he” from the center “sq” of gravity of the skin area “se.”
[0392] Then, in step S 26 , the attention-degree-information generating section JB 1 detects a face direction by using the difference obtained in step S 25 . More specifically, either of the following two methods are, for example, used to detect a face direction by using the difference. It is assumed that X indicates a difference, Y indicates a face-direction angle, and the angle of the face of the conference participant HM 1 is set to 0 degrees when the conference participant HM 1 is directed to the camera of the monitor device MDm. In one method used in step S 26 , prior to face-direction detection processing, data for the difference X and the face-direction angle Y is obtained in advance; the face-direction angle Y corresponding to the difference X is obtained, for example, as the average; their relationship is obtained as shown in FIG. 65 ; and the face-direction angle Y is obtained from the difference X obtained in step S 25 , according to the relationship shown in FIG. 65 . In another method used in step S 26 , the face-direction angle Y is obtained from the following expression (10) by using the difference X obtained in step S 25 .
[0000] Y =α sin( X ) (10)
[0393] With the above flow, the attention-degree-information generating section JB 1 detects the face direction of the conference participant HM 1 .
[0394] In still another method for detecting the direction in which the conference participant HM 1 is directed, for example, an infrared ray is emitted to the face of the conference participant HM 1 ; an infrared ray reflected from the face of the conference participant HM 1 is received to form an image; and the face direction is detected from the image.
[0395] 11. Structure of Monitor Device
[0396] An example specific structure of each of the monitor devices MD 2 to MDn in the structure shown in FIG. 2 will be described next by referring to FIG. 66 and FIG. 67 . FIG. 66 is an outlined internal view of a monitor device MD, viewed from a side. FIG. 67 is an outlined elevation of the monitor device MD.
[0397] In the following description, for simplicity, a case is taken as an example, in which information related to conference participants HM 1 to HMn is displayed on monitor devices MD 1 to MDn in teleconference devices TCD 1 to TCDn.
[0398] In the present embodiment, each of the monitor devices MD 2 to MDn is provided, as shown in FIG. 66 and FIG. 67 , with a cabinet 10 ; a speaker 13 disposed at the front (front of the monitor device MD) of the cabinet 10 ; a display section 15 disposed such that a screen 14 is directed in a predetermined direction (upper direction in the case shown in FIG. 66 ); a half mirror 12 for reflecting light emitted from the screen 14 of the display section 15 towards the front of the monitor device MD along a one-dot chain line BO in the figure and for passing light incident from the front of the monitor device MD along a two-dot chain line BI in the figure; and a camera 16 (such as a video camera) supported by a supporting section 18 behind the half mirror 12 . On the upper surface of the cabinet 10 in the monitor device MD, for example, a microphone 11 supported by a supporting section 17 is also provided.
[0399] The microphone 11 may be provided, for example, only for the monitor device (monitor device MDm in the case shown in FIG. 2 ) disposed at the front of the conference participant HM 1 among the monitor devices MD 2 to MDn.
[0400] The camera 16 of each of the monitor devices MD 2 to MDn receives incident light (such as an optical image of the conference participant HM 1 ) passing through the half mirror 12 along the two-dot chain line BI in FIG. 66 , and converts it to image data. The image data output from the camera 16 is sent to the information transmitting and receiving section TRB 1 of the signal processing device SPD 1 , and then sent to the teleconference devices TCD 2 to TCDn through the communication network NT. The image data output from the camera 16 , for example, of the monitor device MDm disposed at the front of the conference participant HM 1 among the monitor devices MD 2 to MDn is also sent to the attention-degree-information generating section JB 1 of the signal processing device SPD 1 and is used for detecting lines of sight or a face direction when attention-degree information is generated, as described above.
[0401] The microphone 11 of each of the monitor devices MD 2 to MDn converts sound, such as surrounding sound of the teleconference device TCD 1 and what the conference participant HM 1 says, to audio data. The audio data output from the microphone 11 is sent to the information transmitting and receiving section TRB 1 of the signal processing device SPD 1 , and then, sent to the teleconference device TCD 2 to TCDn through the communication network NT.
[0402] On the screen 14 of the display section 15 in the monitor device MD 2 among the monitor devices MD 2 to MDn, an image based on image data (that of the conference participant HM 2 and the surroundings) captured by the camera 16 of the monitor device. MD 1 provided correspondingly to the conference participant HM 1 in the teleconference device TCD 2 and sent through the communication network NT is displayed. From the speaker 13 of the monitor device MD 2 , sound based on audio data (that of what the conference participant HM 2 says) captured by the microphone 11 of the monitor device MD 1 provided correspondingly to the conference participant HM 1 in the teleconference device TCD 2 and sent through the communication network NT is reproduced. In the same way, on the screen 14 of the display section 15 in the monitor device MD 3 , an image based on image data captured by the camera 16 of the monitor device MD 1 provided correspondingly to the conference participant HM 1 in the teleconference device TCD 3 and sent through the communication network NT is displayed. From the speaker 13 of the monitor device MD 3 , sound based on audio data captured by the microphone 11 of the monitor device MD 1 provided correspondingly to the conference participant HM 1 in the teleconference device TCD 3 and sent through the communication network NT is emitted. The situation is the same for the other monitor devices MD. An image sent from the corresponding teleconference device is displayed and sound is emitted.
[0403] In each of the monitor devices MD 2 to MDn in the present embodiment, as shown in FIG. 66 , since light emitted from the screen 14 of the display section 15 is reflected by the half mirror 12 in the direction indicated by the one-dot chain line BO towards the conference participant HM 1 , a face image and the like of the conference participant HM located at the other side is displayed on the screen 14 of the display section 15 as a mirror image, which is reflected by the half mirror 12 to be in a correct state. In FIG. 67 , RV indicates an image (a virtual image of the conference participant HM at the other side) obtained when a mirror image of the conference participant HM located at the other side, displayed on the screen 14 of the display section 15 is reflected by the half mirror 12 .
[0404] When a mirror image of the conference participant at the other side is displayed on the screen 14 of the display section 15 in a monitor device MD in the present embodiment, the positions of the eyes in the virtual image, which are optically conjugate with those of the eyes in the mirror image are displayed so as to almost match the principal point of the lens of the camera 16 through the half mirror 12 . Therefore, the lines of sight of the conference participant HM 1 and those of the conference participant at the other side match.
[0405] More specifically, a case in which the conference participant HM 1 sees the monitor MDm (an image of the conference participant HMm) in the teleconference device TCD 1 and the conference participant HMm sees the monitor device MD 1 (an image of the conference participant HM 1 ) in the teleconference device TCDm is taken as an example and will be described. In this case, a mirror image of the face or the like of the conference participant HMM is displayed on the screen 14 of the display section 15 in the monitor device MDm in the teleconference device TCD 1 ; and the camera 16 of the monitor device MDm captures an image of the conference participant HM 1 who is directed to the monitor device MDm and sends image data to the teleconference device TCDm and others. A mirror image of the face or the like of the conference participant HM 1 is displayed on the screen 14 of the display section 15 in the monitor device MD 1 in the teleconference device TCDm; and the camera 16 of the monitor device MD 1 captures an image of the conference participant HMm who is directed to the monitor device MD 1 and sends image data to the teleconference device TCD 1 and others.
[0406] In this condition, at the teleconference device TCD 1 , when a mirror image of the conference participant HMm at the other side is displayed on the screen 14 of the display section 15 in the monitor device MDm, the positions of the eyes in the virtual image, which are optically conjugate with those of the eyes in the mirror image are displayed so as to almost match the principal point of the lens of the camera 16 . At the same time, at the teleconference device TCDm, when a mirror image of the conference participant HM 1 at the other side is displayed on the screen 14 of the display section 15 in the monitor device MD 1 , the positions of the eyes in the virtual image, which are optically conjugate with those of the eyes in the mirror image are displayed so as to almost match the principal point of the lens of the camera 16 . Therefore, at the teleconference device TCD 1 , the lines of sight of the conference participant HM 1 match those of the virtual image of the conference participant HMm at the other side. At the teleconference device TCDm, the lines of sight of the conference participant HMm match those of the virtual image of the conference participant HM 1 at the other side.
[0407] In general conventional teleconference systems, conference participants do not see virtual images made by half mirrors but directly see images (real images) displayed on the screens of display sections. In addition, cameras are disposed above or below, or at the right or left of the screens of the display sections in their vicinities. Therefore, in general conventional teleconference systems, the lines of sight of conference participants are directed to images (real images) displayed on the screens of the display sections, and are not directed to the lenses of the cameras. Consequently, the lines of sight of the conference participant at the other side, displayed on the screen of a display section does not seem to be directed to you. Unlike the present embodiment, it is impossible to perform conversation while the lines of your sight match those of the conference participant at the other side.
[0408] In contrast, in the teleconference system according to the present embodiment, when the monitor device of each teleconference device TCD has the structure shown in FIG. 66 and FIG. 67 , a conference participant can perform conversation with the conference participant at the other side while they see their eyes each other, namely, the lines of their sight match.
[0409] In the present embodiment, when a plurality of monitor devices MD in a teleconference device TCD are disposed, as shown in FIG. 2 , as if the conference participants HM 2 to HMn located at the teleconference devices TCD 2 to TCDn and the conference participant HM 1 sat around a table, namely, when the plurality of monitor devices are disposed such that the relative positional relationships among the conference participants HM 2 to HMn at the places where the teleconference devices TCD 2 to TCDn are disposed are maintained, not only the lines of sight match between the conference participant HM 1 and the conference participant at the other side, but also the conference participant HM 1 understands whom the other conference participants HM are directed to.
[0410] 12. Example Structure of Each Device
[0411] FIG. 68 shows an actual example device structure which can be used for the signal processing device SPD of each teleconference device TCD or the seating-order determination device GJD, in a teleconference system according to an embodiment of the present invention. These devices can be implemented, for example, by personal computers. The group-determination-table generating device like that shown in FIG. 47 can also be implemented by the following device structure.
[0412] The structure shown in FIG. 68 includes a CPU 100 for controlling each section; a ROM 101 for storing basic input and output systems (BIOS) and various initial values; a RAM 102 for tentatively storing various programs, data, and data obtained during calculation; a hard-disk drive (HDD) 104 for driving a hard disk for storing an operating system (OS), various application programs (computer programs), and other data; a removable-medium drive 105 for driving a removable medium 106 , such as a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, a DVD-R, a DVD-RW, a removable hard disk, and a semiconductor memory; and a communication interface section 103 for connecting to an external communication network (the communication network NT), such as an ISDN, a commercial telephone line, a cable-TV line, and a digital communication-satellite line, and for connecting to an external bus, such as that conforming to the IEEE-1394 standard or a USB, and to various external connection terminals.
[0413] The structure shown in FIG. 68 can further include, for example, an input operation device, such as a mouse or a keyboard, operated by the user and a monitor for displaying information, although they are not shown.
[0414] An application program for implementing the functions of the signal processing device SPD in the teleconference system according to the present embodiment described above, especially the attention-degree-information generating function in the attention-degree-information generating section JB 1 and the information manipulation and distribution function in the information manipulation and distribution section PB, or the group determination processing, the seating-order determination processing, and the seating-order-information generating function is provided by the removable medium 106 or by communication through the communication interface section 103 .
[0415] The application program provided by the removable medium 106 or by the communication interface section 103 is stored in the hard disk of the HDD 104 , is read from the hard disk of the HDD 104 , and tentatively stored in the RAM 102 . The CPU 100 executes various operations in the teleconference system according to the present embodiment according to the application program tentatively stored in the RAM 102 .
[0416] FIG. 69 shows another example structure of the teleconference device TCD 1 .
[0417] In the example structure shown in FIG. 69 , as display means for displaying images of conference participants HM 2 to HMn in teleconference devices TCD 2 to TCDn, the monitor devices MD 2 to MDn, such as those shown in FIG. 2 , corresponding to the teleconference devices TCD 2 to TCDn (the conference participants HM 2 to HMn) are not provided, but, for example, one bent screen 31 is provided and images are displayed on the screen 31 , for example, by a projector.
[0418] In the example structure shown in FIG. 69 , images of the conference participants HM 2 to HMn are displayed on the screen 31 as if the conference participant HM 1 and the other conference participants HM 2 to HMn sat around a table for a conference.
[0419] A camera 34 and a microphone 35 are disposed, for example, at the front of the conference participant HM 1 . Image data of the conference participant HM 1 , captured by the camera 34 and audio data of the conference participant HM 1 , captured by the microphone 35 are sent to the other teleconference devices TCD 2 to TCDn through the communication network NT. In the example structure shown in FIG. 69 , the image data of the conference participant HM 1 , captured by the camera 34 is also sent to the attention-degree-information generating section JB 1 of the signal processing device SPD 1 .
[0420] Audio data of conference participants HM 2 to HMn, sent from the other teleconference devices TCD 2 to TCDn are controlled such that individual sound images are formed in the vicinities of images of the conference participants HM 2 to HMn, displayed on the screen 31 , and are sent to speakers 32 and 33 disposed at the right and left of the screen 31 and emitted. With this control, the positions of images of the conference participants HM 2 to HMn, displayed on the screen 31 almost match those of locations where the voices (sound) of the conference participants HM 2 to HMn are heard.
[0421] In the present embodiment, the attention-degree-information generating section JB is disposed in each of the signal processing devices SPD 1 to SPDn of the teleconference devices TCD 1 to TCDn. On attention-degree-information generating section JB may be independently provided on the communication network NT.
[0422] In the present embodiment, as shown in FIG. 2 , the monitor devices MD 2 to MDn are separated from the signal processing device SPD 1 . Each or one of the monitor devices MD 2 to MDn can have the function of the signal processing device.
[0423] In the present embodiment, as shown in FIG. 1 , the seating-order determination device GJD is independently connected to the communication network NT. Each or one of the teleconference devices TCD 1 to TCDn can have the function of the seating-order determination device.
[0424] In the present embodiment, as examples for detecting a direction, the lines of sight and a face direction are separately detected. They can be detected at the same time.
[0425] In the present embodiment, one conference participant belongs to only one group at each point of time. It is also possible that a plurality of groups is defined, such as a group to which a conference participant mainly belongs and a group in which a conference participant does not give opinions but from which the conference participant wants to obtain information; each conference participant is allowed to belong to a plurality of groups; and a seating order is determined according to which group each of the conference participants at the other sides belongs to.
[0426] As described above, according to the teleconference system of the present embodiment, even when a plurality of conference participants say at the same time, it is easier for a conference participant to listen to a speech in a group which the conference participant belongs to, and it is also easier to see images. Therefore, the teleconference system provides each conference participant with comfort and satisfaction with information. | In a communication system having at least three communication devices communicating with each other, a seating-order determination device for generating seating-order information for information sent from each communication device and for transmitting the seating-order information to each communication device is provided. Each communication device controls the output position of each information according to the seating-order information to output the information sent from the other communication devices in a seating order corresponding to the seating-order information. The seating order is always automatically changed to the most appropriate condition according to the progress of a conference and the state of conversations to provide the user with a comfortable conference environment and a comfortable communication environment. |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This Invention relates to electric generators for producing a reliable flow of electricity. In particular, this invention relates to an individuals ability to independently regenerate, store, manage, and distribute the electricity produced to guarantee a secure and reliable flow of energy to homes, businesses, industries, and critical infrastructures
[0003] 2. Background of the Invention
[0004] Obtaining electricity can be achieved in various ways. For example, an individual can solicit local utility companies for obtaining electrical services.
[0005] Alternatively, an individual can employ a gasoline powered backup generator in the event of a power shortage or blackout.
SUMMARY OF THE INVENTION
[0006] While existing systems and methods work well in general, they have a number of shortcomings. For example, often an individual may not have immediate access to a backup generator during a blackout. Similarly, an individual may not wish to afford the cost associated with the use of solar panels, windmills, turbines, etc.
[0007] The systems and methods of this invention provide tools for assisting an individual in creating a permanent supply of electricity by way of a standalone and/or network-based electric generator, windmill, and/or solar panels. An extension of these tools is the ability for an individual to independently regenerate, store, manage, and distribute the electricity produced to guarantee a secure and dependable flow of energy to homes, businesses, industries, and critical infrastructures.
[0008] These and other features and advantages of this invention are described in or are apparent from the following detailed description of the embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The embodiments of the invention will be described in detail, with reference to the following figures wherein:
[0010] FIG. 1 is a functional block diagram illustrating exemplary electrical system according to this invention;
[0011] FIG. 2 is a screen shot of an exemplary user interface in accordance with an embodiment of this invention;
[0012] FIG. 3 is a screen shot of an exemplary user interface in accordance with an embodiment of this invention;
[0013] FIG. 4 is a screen shot of an exemplary user interface in accordance with an embodiment of this invention;
[0014] FIG. 5 is a screen shot of an exemplary user interface in accordance with an embodiment of this invention;
[0015] FIG. 6 is a screen shot of an exemplary user interface in accordance with an embodiment of this invention;
[0016] FIG. 7 is a diagrammatic view illustrating an embodiment of electrical system according to this invention;
DETAILED DESCRIPTION OF THE INVENTION
[0017] FIG. 1 illustrates an exemplary e-commerce system according to an exemplary embodiment of the invention. Specifically, the electronic commerce system 100 comprises an electrical system 110 , a voice-intelligent phone 200 , a product/server database 300 , a broadcast server 400 , and one or more digital information providers 500 , all interconnected by links 5 and distributed networks 10 .
[0018] The electrical system 110 comprises a network interface 120 , a display device 130 and an input device 140 .
[0019] The voice-intelligent phone 200 comprises a network interface 210 , a display device 220 and an input device 230 . The voice intelligent phone 200 is also connected to a plain old telephone system (POTS) 600 , such as a digital subscriber line, a direct dial connection, or the like, and voice over Internet protocol service provider 610 .
[0020] A product/server database 300 is connected to one or more database server appliances 310 , an application server appliances 320 . Additionally, the broadcast server 400 is connected to one or more video content servers 410 and one or more advertising servers 420 .
[0021] While the exemplary embodiment illustrated in FIG. 1 shows the electronic commerce system 100 and associated components collocated, it is to be appreciated that the various components of the electronic commerce system 100 can be located at distant portions of a distributed network, such as a local area network, a wide area network, an intranet and/or the Internet, or within a dedicated electronic commerce system. Thus, it should be appreciated that the components of the electronic commerce system 100 can be combined into one or more dedicated devices or collocated on a particular node of a distributed network. As it will be appreciated from the following description, and for reasons of computational efficiency, the components of the electronic commerce system can be arranged at any location within a distributed network without affecting the operation of the system.
[0022] Furthermore, the links 5 can be a wired or wireless link or any other known or later developed element(s) that is capable of supplying and communicating electronic data to and from the connected elements. For example, the links 5 can be optical links and communications between the various components based on, for example, the TCP/IP network protocol. Additionally, the input devices 140 and 230 can be, for example, a keyboard, a mouse, a microphone, a speaker, a speech to text converter, a keypad, a digital camera or video recorder, or the like. The display devices 130 and 220 can be a computer monitor, a television, a digital display, an LCD display, or any other analog or digital device capable of displaying audio and/or video information to one or more users.
[0023] In operation, the system is initialized, for example, by a user approaching the electrical system 110 and requesting user authentication. For example, a user enters, via input device 140 , a request for product and/or services. This entry of product and/or service information can be, for example, a free form search, or, alternatively, a customized search where the user is directed, for example, by locality information, by product type, by information type, or the like, to a particular product. For example, FIGS. 2 - 11 illustrate an exemplary tailored search where a user is directed through geographical restrictions and then by product category to the desired product. For example, in FIG. 2 , the user selects a country. Next, in FIG. 3 , the user selects a particular state within that country. Then, a user selects a county within that state in FIG. 4 .
[0024] A user then selects, for example as illustrated in FIG. 5 , a particular mall within that county. Next, a user, for example as illustrated in FIG. 6 , selects a category of store within the selected mall. Then, as illustrated in FIG. 7 , a user selects a particular department store.
[0025] Thus, the kiosk 110 , upon receipt of the product/service information request, forwards the request, via link 5 and one or more distributed networks 10 , to a product/server database 300 . The product/server database 300 queries one or more of the data server appliance 310 and the application server appliance 320 to locate the requested information. The product/server database 300 can operate in a similar manner to commercially available search engines. Furthermore, the database service appliance 310 and the application server appliance 320 could be implemented as servers running, for example, commercially available search engine software. Therefore, the kiosks 110 are able to manage the convergence of voice, video and data over one or more distributed networks.
[0026] Upon locating information pertaining to the requested product/service, the product/service database 300 , forwards, via link 5 and one or more distributed networks 10 , the results of the search to the kiosk 110 , the kiosk 110 receives, via network interface 120 , the results of the search and displays, on display device 130 , the results. A user can then, for example, request additional information about the search or products/service, or alternatively, establish a voice communication via the voice-intelligent phone 200 , and the aid of the network interface 210 and the display device 220 , with, for example, the retailer. The retailer could then, for example, provide additional information about the product/service or, for example, provide real-time inventory information, or, for example, an explanation of how the product works. For example, a retailer could, for example, use a video camera as an input device and transmit real time images of product information to a user located at kiosk 110 . This real time video information could then, for example, be displayed on display device 130 .
[0027] Additionally, the kiosk 110 receives one or more information streams than can be, for example, displayed on display device 130 , or one or more other display devices (not shown) there are associated with the kiosk 110 . One or more of these display devices can display, for example, advertising information, news feeds, television broadcasts, or any other type of digital audio/video information. The information for supplying these displays is forwarded, via links 5 and one or more distributed networks 10 , from broadcast server 400 with the aid of the advertising server 420 , and/or the video content server 410 . Alternatively, information can be provided from one or more digital information providers 500 , via link 5 , and the distributed network 10 . Accordingly, depending on the type of information displayed on one or more of the display devices 130 , the information can come from one or more of the video content server 410 , the advertising server 420 , and the digital information providers 500 .
[0028] The voice-intelligent phone 200 , in cooperation with the POTS 600 , VOIP 610 , and one or more distributed networks 10 and links 5 , manages and controls voice communications between one or more parties, this can be a direct party-to-party communication, a PC to PC connection, a PC to phone connection, or, for example, an audio/video teleconference. The voice-intelligent phone system can operate, for example, using standard voice over internet protocol technology. Additionally, the voice intelligent phone 200 can nm an operating system, such as Windows, RTM, CE, that allows for application layers such that phone directories, or the like can be displayed on the display device 220 . Furthermore, the input device 230 can be a wired or wireless handset that can have embedded remote control buttons that can provide users access to digital television and special program services, whose revenues can also be used, for example, to fund the free phone service. Additionally, the voice intelligent phone can display advertising that is designed, for example, to subsidize connection fees imposed by, for example, a connection provider, thus reducing or eliminating the end user's monthly bill.
[0029] FIG. 12 illustrates an exemplary method for searching a product/service in accordance with an exemplary embodiment of the invention. In particular, control begins in step S 100 and continues to step S 110 . In step S 110 , the system is initialized. Next, in step S 120 , a product/service information request is received. Then, in step S 130 , a search for the requested product/service is conducted. Control then continues to step S 140 .
[0030] In step S 140 , a determination is made whether the requested product/service has been located. If the requested product/service has been located, control continues to step S 150 . Otherwise, control jumps to step S 160 .
[0031] In step S 150 , information relating to the requested products/services is displayed. Control then continues to step S 160 .
[0032] In step S 160 , a determination is made whether to perform another search If another search is to be performed, control continues to step S 170 . Otherwise, control jumps to step S 180 where the control sequence ends.
[0033] In step S 170 , a user can update the request for a product/service. Control then continues back to step S 130 where the search for the requested product/service is conducted
[0034] FIG. 13 illustrates an exemplary method of establishing communication via the voice-intelligent phone. In particular, control begins in step S 200 and continues to step S 210 . In step S 210 , the system is initialized. Next, in step S 220 , one or more phone numbers are input to the voice-intelligent phone. The voice-intelligent phone, in cooperation with, for example, a voice-intelligent phone stream server, establishes a connection in step S 230 with the one or more parties identified in step S 220 . Control then continues to step S 240 .
[0035] In step S 240 , data from the various parties is steamed and distributed. Next, in step S 250 , a query is made whether to end the call. If the call is to be terminated, control continues to step S 260 where the sequence ends. Otherwise, control returns to step S 240 where the audio/video data is continued to be streamed.
[0036] FIG. 14 illustrates an exemplary method of selecting information that could, for example, be displayed on one or more of the display devices 130 or 220 . In particular, control begins in step S 300 and continues to step S 310 . In step S 310 , an information provider is selected. Next, in step S 320 , an information stream is selected. Then, in step S 330 , the selected information is displayed. Control then continues to step S 340 .
[0037] in step S 340 , a determination is made whether new information should be selected. If new information is to be selected, control jumps back to step S 310 . Otherwise, control continues to step S 350 where the control sequence ends.
[0038] FIG. 15 illustrates an exemplary method of determining an information provider based on one or more criteria. In particular, control begins in step S 400 and continues to step S 410 . In step S 410 , the subject matter of, for example, the product/server inquiry is determined. Alternatively, subject matter can be determined, for example, based on the geographical location, environment, time of day, or the like of the kiosk 110 . Next, in step S 420 , an information provider is selected based on the determined subject matter. Then, in step S 430 , an information stream from the selected information provider is selected. Control then continues to step S 440 . In step S 440 , the selected information is displayed. Next, in step S 450 , a determination is made whether new information should be selected. If new information is to be selected, control jumps back to step S 410 . Otherwise, control continues to step S 460 where the control sequence ends.
[0039] As shown in FIG. 1 , the electronic commerce system is implemented either on a single program general purpose computer, or a separate programmed general purpose computer. However, the electronic commerce system can also be implemented on a special purpose computer, a programmed microprocessor or micro controller and peripheral integrated circuit element, an ASIC or other integrated circuit, a digital signal processor, a hard wired electronic or logic circuit such as a discrete element circuit, a programmable logic device such as a PLD, PLA, FPGA, PAL, or the like. In general, any device capable of implementing a finite state machine that is in turn capable of implementing the flow charts illustrated in FIGS. 12-15 can be used to implement the electronic commerce system according to this invention.
[0040] Furthermore, the disclosed method may be readily implemented in software using object or object-oriented software development environments that provide portable source code that can be used on a variety of computer or workstation hardware platforms. Alternatively, the disclosed electronic commerce system can be implemented partially or fully in hardware using standard logic circuit or VLSI design. Whether software or hardware is used to implement the systems in accordance with this invention, is dependent on the speed and/or efficiency requirements of the system, the particular function, and the particular software or hardware systems or microprocessor or microcomputer systems being utilized. The electronic commerce system and methods illustrated herein however, can be readily implemented in hardware and/or software using any known or later developed systems or structures, devices and/or software by those of ordinary skill in the applicable art from the functional description provided herein and with the general basic knowledge of the computer and telecommunications arts.
[0041] Moreover, the disclosed methods may be readily implemented as software executed on a programmed general purpose computer, a special purpose computer, a microprocessor, or the like. In these instances, the methods and systems of this invention can be implemented as a program embedded on a personal computer such as a Java, RTM, or a CGI script, as a resource residing on a server or a graphics workstation, as a routine embedded in an electronic commerce system, a web browser, an electronic commerce enabled cellular telephone, a PDA, a dedicated electronic commerce management system, or the like. The electronic commerce system can also be implemented by physically incorporating the system into a software and/or hardware system, such as the hardware and software of a graphics workstation or dedicated electronic commerce management system.
[0042] It is, therefore, apparent that there has been provided, in accordance with the present invention, systems and methods for electronic commerce. While this invention has been described in conjunction with a number of embodiments, it is evident that many alternatives, modifications and variations would be or are apparent to those of ordinary skill in the applicable arts. Accordingly, it is the intent to embrace all such alternatives, modifications, equivalents and variations that are within the spirit and scope of this invention. | Provided herein the tools for assisting an individual in creating a permanent supply of virtual electricity by way of a standalone and/or network-based electric generator, windmill, and/or solar panels. An extension of these tools is the ability for an individual to independently regenerate, stockpile, regulate, and distribute electricity to eliminate blackouts and guarantee a secure and dependable flow of energy to homes, businesses, industries, and critical infrastructures. |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a divisional of and claims the benefit of U.S. application Ser. No. 09/724,899 filed Nov. 28, 2000 U.S. Pat. No. 6,514,399, which is a continuation of U.S. Ser. No. 09/179,242 filed Oct. 26, 1998 (now U.S. Pat. No. 6,156,181), which is a continuation of U.S. Ser. No. 08/843,212 filed Apr. 14, 1997 (now U.S. Pat. No. 5,885,470) and which claims the benefit of U.S. S No. 60/015,498 filed Apr. 6, 1996, the disclosures of which are incorporated by reference in their entirety for all purposes.
BACKGROUND OF THE INVENTION
There has recently been an increasing interest in the application of manufacturing techniques common to the electronics industry, such as photolithography, wet chemical etching, etc., to the microfabrication of fluidic devices for use in obtaining chemical and biochemical information.
The manufacture of fluidic devices in solid substrates, e.g., silicon, glass, etc., was described as early as 1979, with the disclosure of the Stanford Gas Chromatograph (discussed in Manz et al., Avd. in Chromatog. (1993) 33:1-66, citing Terry et al., IEEE Trans. Electron. Devices (1979) ED-26:1880). These fabrication technologies have since been applied to the production of more complex devices for a wider variety of applications.
To date, the most prominent use of this technology has been in the area of capillary electrophoresis (CE). Capillary electrophoresis typically involves the injection of a macromolecule containing sample, e.g., nucleic acids or proteins, into one end of a thin capillary. A potential is then applied along the length of the capillary to electrophoretically draw the materials contained within the sample through the channel. The macromolecules present in the sample then separate from each other based upon differences in their electrophoretic mobility within the capillary. Such differences in electrophoretic mobility typically result from differences in the charge and/or size of a compound. Other factors can also affect the electrophoretic mobility of a given compound, such as interactions between the compound and the capillary walls, interactions with other compounds, conformation of the compound, and the like.
Capillary electrophoresis methods have traditionally employed fused silica capillaries for the performance of these electrophoretic separations. In more recent applications, this fused silica capillary has been replaced by an etched channel in a solid planar substrate, e.g., a glass or silica slide or substrate. A covering layer or substrate provides the last wall of the capillary.
Early discussions of the use of this planar substrate technology for fabrication of such devices are provided in Manz et al., Trends in Anal. Chem. (1990) 10 (5): 144-149 and Manz et al., Adv. in Chromatog. (1993) 33:1-66, which describe the fabrication of fluidic devices and particularly capillary electrophoresis devices, in silicon and glass substrates.
Although generally concerned with the movement of material in small scale channels, as the name implies, capillary electrophoresis methods employ electrophoresis to affect that material movement, e.g., the movement of charged species when subjected to an electric field. While providing significant improvements in the separation of materials, these capillary electrophoresis methods cannot be used in the direction of bulk materials or fluids within microscale systems. In particular, because electrophoresis is the force which drives the movement of materials in CE systems, species within the material to be moved which have different electrophoretic mobilities will move at different rates. This results in a separation of the constituent elements of the material. While this typically is not a problem in CE applications, where separation is the ultimate goal, where the goal is the bulk transport of fluid borne materials from one location to another, electrophoretic separation of the constituent elements of that material can create numerous problems. Such problems include excessive dilution of materials in order to ensure complete transport of all materials, biasing of a transported material in favor if faster electrophoresing species and against slower or even oppositely electrophoresing species.
While mechanical fluid direction systems have been discussed for moving and directing fluids within microscale devices, e.g., utilizing external pressures or internal microfabricated pumps and valves, these methods generally require the use of costly microfabrication methods, and/or bulky and expensive equipment external to the microfluidic systems. Accordingly, it would generally be desirable to produce a microscale fluidic device that can be easily and cheaply manufactured. The present invention meets these and other needs.
SUMMARY OF THE INVENTION
It is a general object of the invention to provide microfluidic devices for the performance of chemical and biochemical analyses, syntheses and detection. The devices of the invention combine precise fluidic control systems with microfabricated polymeric substrates to provide accurate, low cost, miniaturized analytical devices that have broad applications in the fields of chemistry, biochemistry, biotechnology, molecular biology and numerous other fields.
In a first aspect, the present invention provides a microfluidic system which includes a microfluidic device. The device comprises a body that is substantially fabricated from a polymeric material. The body includes at least two intersecting channels disposed therein, where the interior surfaces of these channels have a surface potential associated therewith, which is capable of supporting sufficient electroosmotic mobility of a fluid disposed within the channels. At least one of the two intersecting channels has at least one cross sectional dimension in the range of from about 0.1 μm to about 500 μm. The device also includes at least first, second and third ports disposed at termini of the first channel and at least one terminus of the second channel, and these ports are in electrical contact with fluid in the channels. The system also includes an electrical control system for concomitantly applying a voltage at the three ports, to selectively direct flow of a fluid within the intersecting channels by electroosmotic flow.
The present invention also provides a method of fabricating microfluidic devices for use with an electroosmotic fluid direction system. The method comprises molding a polymeric material to form a substrate that has at least one surface, and at least first and second intersecting channels disposed in that surface. Each of the at least first and second intersecting channels has an interior surface which has a surface potential associated therewith, which is capable of supporting sufficient electroosmotic flow of a fluid in those channels. Again, at least one of the intersecting channels has at least one cross-sectional dimension in the range of from about 0.1 μm to about 500 μm. A cover layer is overlaid on the surface of the substrate, whereby the cover layer encloses the intersecting channels. Together, the substrate and cover layer will also comprise at least three ports disposed therein, each of the at least three ports being in fluid communication with first and second termini of said first channel and at least one terminus of the second channel.
In a related aspect, the present invention also provides a method for directing movement of a fluid within a microfluidic device. The method comprises providing a microfluidic device having at least first and second intersecting channels disposed therein. Each of the first and second intersecting channels has a fluid disposed therein, wherein the at least first and second channels have interior surfaces having a surface potential associated therewith, which is capable of supporting sufficient electroosmotic mobility of the fluid disposed in those channels. The device also includes at least first, second, third and fourth ports disposed in the substrate, wherein the first and second ports are in fluid communication with the first channel on different sides of the intersection of the first channel with the second channel, and the third and fourth ports are in fluid communication with the second channel on different sides or the intersection of the second channel with the first channel. A voltage gradient is then applied between at least two of the first, second, third and fourth ports to affect movement or said fluid in at least one of the first and second intersecting channels.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic illustration of one embodiment of a microfluidic system.
FIG. 2 is a schematic illustration of one embodiment of a microfluidic device of the present invention.
FIG. 3 is a plot illustrating electroosmotic transport of a neutral fluorescent dye past a detector in a microfluidic channel, fabricated in a polymeric substrate.
DETAILED DESCRIPTION OF THE INVENTION
The present invention generally provides microfluidic devices and systems, as well as methods for using such devices and systems. The devices and systems of the present invention are generally characterized in that they typically include precise fluid direction and control systems, and that they are largely fabricated from polymeric materials. These two characteristics provide the microfluidic devices and systems of the present invention with a number of advantages over previously used materials, such as silica based substrates, semiconductor substrates, e.g., silicon, and the like, including ease of manufacturing, low cost of materials, and inertness to a wide range of potential reaction conditions, including salts, pH and application of electric fields. In addition, these devices and systems also are generally characterized by their inclusion of, or adaptability to precise fluid direction and control elements.
I. Microfluidics, Generally
As noted above, the present invention generally relates to microfluidic devices and systems, which include precise fluid control elements, e.g., fluid transport and direction systems, and which are fabricated from polymeric substrates.
The term “microfluidic device” as used herein, refers to a device or aggregation of devices, which includes a plurality of interconnected channels or chambers, through which materials, and particularly fluid borne materials may be transported to effect one or more preparative or analytical manipulations on those materials. Typically, such channels or chambers will include at least one cross sectional dimension that is in the range of from about 0.1 μm to about 500 μm, and preferably from about 1 μm to about 100 μm. Dimensions may also range from about 5 μm to about 100 μm. Use of dimensions of this order allows the incorporation of a greater number of channels, chambers or sample wells in a smaller area, and utilizes smaller volumes of reagents, samples and other fluids for performing the preparative or analytical manipulation of the sample that is desired.
The microfluidic device may exist alone or may be a part of a microfluidic system which can include: sampling systems for introducing fluids, e.g., samples, reagents, buffers and the like, into the device; detection systems; data storage systems; and control systems, for controlling fluid transport and direction within the device, monitoring and controlling environmental conditions to which the fluids in the device are subjected, e.g., temperature, current and the like. A schematic illustration of one embodiment of such a system is shown in FIG. 1 . As shown, the system includes a microfluidic device 100 . The device, and particularly the reagent wells or ports of the device are electrically connected to voltage controller 110 , which controls fluid transport within the device. An example of a particularly preferred voltage controller is described in, e.g., U.S. patent application Ser. No. 08/691,0632, filed Aug. 2, 1996, and incorpoated herein by reference in its entirety for all purposes. Detection of the output of the device is carried out by detector 120 . Both detector 120 and voltage controller 110 are connected to computer 130 , which instructs voltage controller in the selective application of varying voltage levels to the various ports of the device 100 . The computer also receives and stores detection data from detector 120 , and is typically appropriately programmed to perform analysis of those data.
Microfabricated fluidic substrates have been described for the performance of a number of analytical reactions. For example, U.S. Pat. No. 5,495,392 to Wilding and Kricka, describes a mesoscale apparatus which includes microfabricated fluid channels and chambers in a solid substrate for the performance of nucleic acid amplification reactions. Further, U.S. Pat. No. 5,304,487 to Wilding and Kricka also describes a mesoscale device for detecting an analyte in a sample which device includes a cell handling region. The device also includes microfabricated channels and chambers having at least one cross-sectional dimension in the range of from 0.1 μm to about 500 μm. Similar devices are also described in U.S. Pat. Nos. 5,296,375, 5,304,487, 5,427,946, and 5,486,335, also to Wilding and Kricka, for detection of cell motility and fluid characteristics, e.g., flow restriction as a function of analyte concentration. The disclosure of each of these patents is incorporated herein by reference.
III. Polymeric Substrates
Typically, fabrication of fluidic systems having small or even microscale dimensions has drawn on techniques that are widely used in the electronics industry, such as photolithography, wet chemical etching, controlled vapor deposition, laser drilling, and the like. As a result, these microfabricated systems have typically been manufactured from materials that are compatible with these manufacturing techniques, such as silica, silicon, gallium arsenide and the like. While each of these materials is well suited for microfabrication, and many are well suited for inclusion in microfluidic systems, the costs associated with the materials and manufacture of devices utilizing such materials renders that use commercially impractical.
The present invention on the other hand, is characterized in that the devices are substantially fabricated from polymeric materials. By “Polymeric Substrates” or “Polymeric Materials” is generally meant organic, e.g., hydrocarbon based, polymers that are capable of forming rigid or semi-rigid structures or substrates. By “substantially fabricated from polymeric materials” is meant that greater than 50% (w/w) of the materials used to manufacture the microfluidic devices described herein are polymeric materials. For example, while a substrate may be fabricated entirely of a polymeric material, that substrate may also include other non-polymeric elements incorporated therein, including, e.g., electrodes, glass or quartz detection windows, glass cover layers and the like. Typically, the devices of the present invention comprise greater than 60% polymeric materials, preferably greater than 70%, more preferably greater than 80% and often greater than 95% polymeric materials.
Microfabrication of polymeric substrates for use in the devices of the invention may be carried out by a variety of well known methods. In particular, polymeric substrates may be prepared using manufacturing methods that are common in the microfabrication industry, such as injection molding or stamp molding/embossing methods where a polymeric substrate is pressed against an appropriate mold to emboss the surface of the substrate with the appropriate channel structures. Utilizing these methods, large numbers of substrates may be produced using, e.g., rolling presses or stamps, to produce large sheets of substrates. Typically, these methods utilize molds or stamps that are themselves, fabricated using the above-described, or related microfabrication techniques.
Although generally not preferred for the manufacture of polymeric substrates for cost reasons, other microfabrication techniques are also suitable for preparation of polymeric substrates, including, e.g., laser drilling, etching techniques, and photolithographic techniques. Such photolithographic methods generally involve exposing the polymeric substrate through an appropriate photolithographic mask, i.e., representing the desired pattern of channels and chambers, to a degradative level of radiation, e.g., UV light for set periods of time. The exposure then results in degradation of portions of the surface of the substrate resulting in the formation of indentations which correspond to the channels and/or chambers of the device.
Suitable polymeric materials for use in fabricating substrates are generally selected based upon their compatibility with the conditions present in the particular operation to be performed by the device. Such conditions can include extremes of pH, temperature and salt concentration. Additionally, substrate materials are also selected for their inertness to critical components of an analysis or synthesis to be carried out by the device, e.g., proteins, nucleic acids and the like.
Polymeric substrate materials may be rigid, semi-rigid, or non-rigid, opaque, semi-opaque or transparent, depending upon the use for which they are intended. For example, devices which include an optical or visual detection element, e.g., for use in fluorescence based or calorimetric assays, will generally be fabricated, at least in part, from a transparent polymeric material to facilitate that detection. Alternatively, transparent windows of, e.g., glass or quartz, may be incorporated into the device to allow for these detection elements. Additionally, the polymeric materials may have linear or branched backbones, and may be cross-linked or non-cross-linked. Examples of preferred polymeric materials include, e.g., polydimethylsiloxanes (PDMS), polymethylmethacrylate (PMMA), polyurethane, polyvinylchloride (PVC), polystyrene, polysulfone, polycarbonate and the like.
Typically, the polymeric substrates used in the devices of the present invention are fabricated in two or more parts. Specifically, a first planar substrate element is provided having a plurality of grooves and/or wells, corresponding to the fluid channels and/or chambers, manufactured, e.g., molded or machined, into one of its planar surfaces. These grooves provide the bottom and side walls of the channels and chambers of the devices. A second planar substrate element is then mated with the first to define the top wall of the channels and chambers. The two members are bonded together in order to ensure that the channels and chambers in the substrate are fluid tight. Bonding of the two members may be accomplished by a number of methods that are known in the art, such as through the use of adhesives, e.g., UV curable adhesives, or by sonically welding one member to the other, e.g., as described in Published PCT Application No. WO 95/12608, which is incorporated herein by reference in its entirety for all purposes. Alternatively, the two planar elements may be bonded by applying pressure to the joined pair under elevated temperatures, sufficient to bond the two planar elements together.
As described above, the polymeric substrate may be rigid, semi-rigid, nonrigid or a combination of rigid and nonrigid elements, depending upon the particular application for which the device is to be used. In one particular embodiment, a substrate is made up of at least one softer, flexible substrate element and at least one harder, more rigid substrate element, one of which includes the channels and chambers manufactured into its surface. Upon mating the two substrates, the natural adhesion of the soft, less rigid substrate, either to another less rigid substrate or to a more rigid substrate, allows formation of an effective fluid seal for the channels and chambers, obviating the difficulties associated with gluing or melting more rigid plastic components together.
III. Fluid Direction System
The devices of the present invention, in addition to being largely fabricated from polymeric substrates, also are generally characterized by the use of fluid transport and direction systems that do not employ mechanical pumps or valves, or the application of external pressure to selectively move and direct the fluids through the various channels or chambers contained in the device or system. Instead, the microfluidic devices and systems of the present invention typically utilize controlled electroosmotic flow to transport and selectively direct fluids among and through the interconnected series of channels contained within the device. One example of such controlled electroosmotic flow is described in published International Patent Application No. WO 96/04547 to Ramsey, which is incorporated herein by reference in its entirety for all purposes.
In brief, when an appropriate fluid is placed in a channel or other fluid conduit having functional groups present at the surface, those groups can ionize. For example, where the surface of the channel includes hydroxyl functional groups at the surface, i.e., as in the case of silica, protons can leave the surface of the channel and enter the fluid. Under such conditions, the surface will possess a net negative charge, whereas the fluid will possess an excess of protons or positive charge particularly localized near the interface between the channel surface and the fluid. By applying an electric field across the length of the channel, cations will flow toward the negative electrode. Movement of the positively charged species in the fluid pulls the solvent with them. The steady state velocity of this fluid movement in the channel is directly proportional to the zeta potential of the surface that is in contact with the fluid being moved (See, e.g., Published International Application No. WO. 96/04547, previously incorporated herein).
Fluid velocity within a channel is also generally given as:
v =(μ EO ) E
Where v is the velocity of the fluid, μEO is the electroosmotic mobility of the fluid in the system, and E is the electric field strength. Thus, the electroosmotic mobility of the fluid is also directly proportional to the zeta potential of the surface that is contacting the fluid.
The fluid flow rate, or volume velocity, within a specific channel (Q) is then given as:
Q =(μ EO ) EA
where μEO and E are as defined above, Q is the volume velocity of the fluid and A is the cross sectional area of the channel through which the fluid is flowing. Using the above equations, therefore, one can calculate the electroosmotic mobility of a given fluid in a given channel from either its velocity or its volumetric flow rate, e.g., in cm 3 /second.
Accordingly, the electroosmotic fluid control systems employed in the devices of the present invention generally require channels having surfaces with sufficient zeta potentials to propagate an acceptable level of electroosmotic mobility within those channels.
This zeta potential requirement, in combination with the availability of suitable manufacturing techniques as described above, has resulted in silica substrates generally being employed for systems utilizing such electroosmotic flow. Optimized planar silica substrates having channels fabricated into their surfaces, have generally supported an electroosmotic mobility of approximately 5×10 −4 cm 2 V −1 s −1 for a 5 mM Sodium borate buffer at pH 7, that is disposed within those channels.
However, as noted above, the devices and systems of the present invention utilize polymeric substrates. In general, such polymeric materials generally have hydrophobic surfaces and will have relatively low surface potentials, generally making them less suitable for electroosmotic flow systems.
Accordingly, incorporation of the electroosmotic fluid control systems described above, into the polymeric substrates used in the present invention, typically requires either: (1) selection of a polymeric material which has a surface potential capable of supporting sufficient electroosmotic mobility of a fluid disposed in contact with that surface; or (2) modification of the surfaces of the polymeric substrate that are to be in contact with fluids, to provide a surface potential that is capable of supporting sufficient electroosmotic mobility. As used herein, the phrase “support sufficient electroosmotic mobility” means that the surfaces in contact with the fluid, e.g., the walls of a channel, possess a sufficient zeta potential, whereby those surfaces or channel walls are capable of supporting an electroosmotic mobility (μEO) of at least about 1×10 −5 cm 2 V −1 s −1 , for a buffer when that buffer is in contact with those walls, e.g., disposed within those channels, e.g., a buffer of from about 1 mM to about 100 mM sodium borate at a pH of from about 6 to about 9. For the purposes of the present invention, μEO is referred to in terms of a standard buffer of from about 1 mM to about 10 mM sodium borate buffer, at a pH of from about 7 to about 9, for example, 5 mM sodium borate, pH 7. In preferred aspects, the surfaces in contact with the fluid are capable of supporting a μEO under the above conditions, of at least about 2×10 −5 cm 2 V −1 s −1 , preferably, at least about 5×10 −5 cm 2 V −1 s −1 , and in particularly preferred aspects, at least about 1×10 −4 cm 2 V −1 s −1 .
Although the above listed polymeric materials possess sufficient surface potential to support sufficient electroosmotic mobility of fluids in contact therewith, in the case of many polymeric materials, the surface potential is so low that it does not support sufficient electroosmotic mobility, as defined above. As such, systems that employ these polymeric materials, without modification, are largely commercially impractical for use in microfluidic devices, due to the extremely slow rates attainable for fluid transport.
Accordingly, in particularly preferred aspects, the surfaces of the polymeric material that are to be in contact with the fluids of interest, and thus contributing and supporting E/O mobility, are subjected to modification to effectively increase the zeta potential of those surfaces, and thus improve E/O mobility achievable within devices fabricated from these materials.
Surface modification of polymeric substrates may take on a variety of different forms, including coating those surface with an appropriately charged material, derivatizing molecules present on the surface to yield charged groups on that surface, and/or coupling charged compounds to the surface.
One example of an embodiment employing a surface coating method involves using a polymeric substrate which includes a surface that comprises a fluorocarbon polymer, e.g., polytetrafluoroethylene (Teflon), which on its own has a very low surface potential. The substrate may be fabricated in whole or in part from the fluorocarbon polymer, or alternatively, the polymer may be applied as a coating on a polymeric substrate of a different composition.
The surfaces of the substrate that are to be in contact with the fluid are then treated with charged, fluorinated modifier compounds, commercially available from, e.g., J & W Scientific (Folsom, Calif.). These fluorinated modifier compounds interact with the fluorocarbon polymer surface of the substrate to present charged functional groups at that surface. These modifiers are available in anionic or cationic forms.
The coating of the surfaces that are intended to contact the fluids within the device may be performed on the assembled microfluidic device, e.g., by pumping the perfluoronated compounds through the channels and/or chambers of the device. Alternatively, the entire surface of the substrate, including the surfaces of the channels and chambers, may be subjected to treatment, e.g., by immersion in or deposition of these compounds on that surface.
In a related aspect, detergents with their charged head groups and hydrophobic tails, function as particularly desirable coating materials. Upon passing such materials through the channels of the system, the hydrophobic tails of the detergent will localize to the hydrophobic surface of the substrate, thereby presenting the charged head group to the fluid layer, creating a charged surface. More particularly, preparation of a charged surface on the substrate involves the exposure of the surface to be modified, e.g., the channels and/or reaction chambers, to an appropriate solvent which partially dissolves or softens the surface of the polymeric substrate. Selection of appropriate solvents will generally depend upon the polymeric material that is used for the substrate. For example, chlorinated hydrocarbon solvents, i.e., trichloroethane (TCE), dichloroethane and the like, are particularly useful as solvents for use with PMMA and polycarbonate polymers.
A detergent solution is then contacted with the partially dissolved surface, whereby the hydrophobic portion of the detergent molecules will associate with the partially dissolve polymer. A wide variety of detergents may be used in this method, and are generally selected based upon their compatibility with the ultimate end use of the microfluidic device or system, including without limitation, for example, SDS (sodium dodecyl sulfate), DTAB (dodecyltrimethylammonium bromide), or CTAB (cetyltrimethylammoniumbromide). Following contacting the polymer with the appropriate detergent, the solvent is then washed from the surface, e.g., using water, whereupon the polymer surface hardens with the detergent embedded into the surface, presenting the charged head group to the fluid interface.
Differentially charged areas may be selected and prepared using a photolyzable detergent, which photolyzes to produce a positively or negatively charged group. Irradiation of selected areas on the substrate surface then fields these charged groups in these areas.
In alternative aspects, the polymeric materials, either as the substrate, or as a coating on the substrate, may themselves be modified, derivatized, etc., to present an appropriate zeta potential at the fluid interface.
For example, once a polymeric material has been molded or otherwise fabricated into a substrate as described herein, the surfaces of that substrate may be modified or activated, e.g., by oxygen plasma irradiation of those surfaces. Polydimethylsiloxane (PDMS), for example, may be modified by plasma irradiation, which oxidizes the methyl groups present in the polymer, liberating the carbon atoms and leaving hydroxyl groups in their place. This modification effectively creates a glass-like surface on the polymeric material, with its associated hydroxyl functional groups. As noted above, this type of surface is well suited for propagation of electroosmotic mobility of fluids.
In an alternate but related aspect, block copolymers may be used in combination with the polymer of interest, to present an appropriate surface for the device. For example, polytetrafluoroethylene/polyurethane block copolymer may be mixed with a polyurethane polymer prior to molding the substrate. The immiscibility of the polytetrafluoroethylene portion of the copolymer in the polyurethane results in that copolymer localizing at the surface of the polyurethane substrate. This surface can then be treated as described above, e.g., using fluorinated buffer modifiers.
IV. Microfluidic Devices
As noted above, the devices and systems of the present invention are characterized in that they are fabricated largely from polymeric substrates, and in that they employ controlled electroosmotic flow in selectively transporting and directing fluids through interconnected channels and/or chambers, that are contained within these microfluidic systems. By “selectively transporting and directing” is meant the transporting of fluids through miroscale or microfluidic channels, and the selective direction, e.g., dispensing, aliquoting or valving, of discrete quantities of those fluids among interconnected channels, e.g., from one channel to another.
Accordingly, in preferred aspects, the devices and systems of the invention generally comprise a body having at least two intersecting channels disposed within it, which body is fabricated, at least in-part, from a polymeric material. Typically, the body includes a polymeric substrate having the intersecting channels fabricated into a substantially flat surface of the substrate as grooves. A cover is then overlaid on this surface to seal the grooves and thereby form the channels.
In order to effectively and accurately control fluid direction in intersecting channel structures, the fluid direction systems used in the devices and systems of the present invention typically include a plurality of ports or reservoirs that are in electrical contact and typically in fluid communication with the channels on different sides of the various intersections. Typically, such ports are placed at and in electrical contact with the free termini of the intersecting channels. By “free termini” or “free terminus” is generally meant that a particular terminus of a channel is not the result of an intersection between that channel and another channel. Often such ports comprise holes disposed through the cover layer which overlays the first substrate, thereby forming wells or reservoirs at these channel termini.
These ports generally provide an access for electrodes to be placed in contact with fluids contained within the channels, as well as providing an access for introducing fluids, and reservoirs or storing fluids in the devices.
Although they can exist as part of a separate device employed in an overall microfluidic system, a number of additional elements may be added to the polymeric substrate to provide for the electroosmotic fluid control systems. These elements may be added either during the substrate formation process, i.e., during the molding or stamping steps, or they may be added during a separate, subsequent manufacturing step. These elements typically include electrodes for the application of voltages to the various fluid reservoirs, and in some embodiments, voltage sensors at the various channel intersections to monitor the voltage applied.
Where electrodes are included as an integrated element of the microfluidic device, they may be incorporated during the molding process, i.e., by patterning the electrodes within the mold so that upon introduction of the polymeric material into the mold, the electrodes will be appropriately placed and fixed within the substrate. Alternatively, the electrodes and other elements may be added after the substrate is formed, using well known microfabrication methods, e.g., sputtering or controlled vapor deposition methods followed by chemical etching, and the like.
In operation, the materials stored in the reservoirs are transported electroosmotically through the channel system, delivering appropriate volumes of the various materials to one or more regions on the substrate in order to carry out a desired analysis or synthesis.
To provide such controlled electroosmotic flow, the microfluidic system includes a voltage controller electrically connected to electrodes placed or fabricated into the various reagent wells on the device. The voltage controller is capable of applying selectable voltage levels, to each of the ports or reservoirs, including ground. Such a voltage controller can be implemented using multiple voltage dividers and multiple relays to obtain the selectable voltage levels desired. Typically, the voltage controller is interfaced with a computer or other processor, e.g., a PC compatible Pentium microprocessor based or Macintosh Power PC computer, which is programmed to instruct appropriate application of voltages to the various electrodes.
In operation, fluid transport within these devices is carried out by applying a voltage gradient along the path of desired fluid flow, thereby electroosmotically driving fluid flow along that path. Some methods for affecting electroosmotic fluid flow incorporate a “floating port” fluid direction system, where a sample fluid in one reservoir and channel is drawn across the intersection of that channel with another channel, by applying a voltage gradient along the length of the first channel, i.e., by concomitantly applying a voltage to the two ports at the ends of the first channel. Meanwhile, the two ports at the ends of the second channel are allowed to “float,” i.e., no voltage is applied. The plug of sample fluid at the intersection is then drawn into the second channel by applying a potential to the electrodes at each end of the second channel. While this method allows injection of a sample of one fluid into a different channel, a number of disadvantages remain. In particular, leakage can occur at the sample intersection as a result of fluid convection, e.g., fluid from one channel “bleeds over” into the other channel. This bleeding over effect can result in imprecise and nonreproducible fluid movements, which can be problematic where one desires more precise fluid control.
However, in preferred aspects, the fluid control and direction systems incorporated into the systems of the present invention apply voltages to multiple reservoirs, simultaneously. In the case of a fluid being transported in a first channel through an intersection with a second channel, this permits the introduction of constraining or directing flows from the second channel, whereby one can precisely control the level of fluid flow in a given direction. This simultaneous application of potential to multiple ports allows for specific control of the fluid at the intersection of the channels, reducing or eliminating the convective effects that are generally seen with floating port methods. For example, a fluid of interest flowing through an intersection of two channels may be precisely constrained by flowing additional fluids from the side channels by appropriate, simultaneous application of voltages to the reservoirs or ports at the ends of those channels, resulting in the fluid of interest being maintained in a “pinched” conformation which prevents bleeding over into the side channels. The volume of the fluid of interest contained within the intersection is readily calculable based upon the volume of the intersection, and also is readily reproducible. Further, this volume of fluid can be readily diverted to one of the intersecting channels by appropriate modulation of the potentials applied at each reservoir or port.
In a related aspect, fluid flow in a first channel past an intersection with a second channel may be “gated” or “valved” by fluid flow in the second channel through that intersection. Although described in terms of a valve, it will be readily apparent that fluid direction using these methods requires no actual mechanical valve, but instead relies upon application of electrical forces through the intersection.
By opening and closing the “valve” through appropriate switching of voltage applied to the reservoirs, one can effectively meter the amount of fluid flowing in the first channel past the intersection. Both pinched and gated control systems are described in significant detail in published International Application No. WO 96/04547, previously incorporated by reference.
In addition to these pinched and gated flow systems, application the simultaneous application of voltages at multiple, e.g., three or more ports, permits controlled fluid flow in more complex interconnected channel structures. For example, in flowing of fluids through interconnected parallel channels, voltages may be applied to multiple reservoirs in order to drive simultaneous flow in the parallel channels without the generation of transverse electric fields which can effectively short circuit the system.
As alluded to above, incorporation of these electroosmotic flow systems into the microfluidic devices and systems of the present invention, generally obviates the need for the incorporation of mechanical fluid direction systems, e.g., microfabricated pumps, valves and the like, within the device itself, or for external fluid movement systems which rely upon pressure flow of materials, e.g., pneumatic systems. Effectively, such systems provide virtual pumps and valves for fluid transport and direction, which pumps and valves have no moving parts.
The number of ports at which voltage may be simultaneously controlled will generally depend upon the complexity of the operation to be performed by the device. Typically, the devices of the invention will include at least three ports at which the voltage is simultaneously controlled, preferably, at least four, more preferably at least five, and in some embodiments will employ six or more ports where the voltage is simultaneously controlled.
FIG. 2 is an illustration of a microfluidic device according to the present invention. As shown, the device 100 , comprises a body, which is entirely or substantially fabricated from a polymeric material. The body includes a plurality of interconnected channels disposed in it, for the transport and direction of fluids.
As shown in FIG. 2, the device 100 is fabricated from a planar substrate 202 , which has the various channels fabricated into its surface. A second planar layer overlays the first and includes holes disposed through it to form the various reservoirs (cover layer not shown). These reservoirs also serve as the ports at which the various electrodes are placed into electrical contact with fluids in the system. This second planar element is then bonded to the first.
The device illustrated, includes a main fluid channel 204 which runs longitudinally down the central portion of the substrate 202 . The main channel 204 originates in and is in fluid communication with buffer channel 206 , and terminates, and is in fluid communication with waste reservoirs 208 . Buffer channel 206 is in fluid communication with two buffer reservoirs 210 and 212 . The device is shown having a number of channels intersecting the main channel 204 . For example, buffer channel 214 terminates in, and is in fluid communication with main channel 204 near its originating point, and is at its other terminus, in fluid communication with buffer reservoir 216 . Sample introduction channel 218 also terminates in and is in fluid communication with main channel 204 , and is, at its other terminus, in fluid communication with sample reservoir 220 . Additional buffer/waste channels 222 and 224 , and buffer/waste reservoirs 226 and 228 are also shown. A detection window 230 , i.e., or detecting the transit of fluorescent or other dyes is also shown. The descriptors for the various wells and channels are primarily offered for purposes of distinguishing the various channels and wells from each other. It will be appreciated that the various wells and channels can be used for a variety of different reagents, depending upon the analysis to be performed.
Application of an electroosmotic flow system into the device shown involves placing electrodes into electrical contact with each of the various reservoirs. By modulating the voltages applied at each of these electrodes, e.g., applying voltage gradients across selected flow/current paths, one can selectively control and direct fluid flow/material transport within the device, as described above. In some aspects, the fluid control system may include optional sensor channels (not shown), for monitoring the voltage at the various intersections.
Although illustrated in terms of a seven reservoir microfluidic device, electroosmotic fluid direction systems can be readily employed in the transport and direction of materials in more complex channel structures or performing a variety of specific manipulations, analyses, preparations, and the like. Examples of such channel structures are described in now abandoned, commonly owned U.S. patent application Ser. No. 08/761,575, filed Dec. 6, 1996, and incorporated herein by reference in its entirety for all purposes.
V. Applications
The microfluidic devices and systems of the present invention are capable of broad application and may generally be used in the performance of chemical and biochemical synthesis, analysis and detection methods. Generally, the devices of the invention can replace conventional laboratory equipment and methods, including measuring and dispensing equipment, as well as more complex analytical equipment, e.g., HPLC, SDS-PAGE, and immunoassay systems.
For example, these devices may be employed in research, diagnostics, environmental assessment and the like. In particular, these devices, with their micron and submicron scales, volumetric fluid control systems, and integratability, may generally be designed to perform a variety of chemical and biochemical operations where these traits are desirable or even required. In addition, these devices may be used in performing a large number of specific assays that are routinely performed at a much larger scale and at a much greater cost, e.g., immunoassays.
The devices may also be used to carry out specific operations in the analysis or synthesis of a sample. For example, the devices may include reaction chambers for performing synthesis, amplification or extension reactions. The devices may similarly include sample analysis elements for the detection of a particular characteristic of the sample, such as a capillary channel for performing electrophoresis on the sample. In such cases, and as described previously, devices for use in such detection methods will generally include a transparent detection window for optical or visual detection.
Examples of some more specific applications of these devices are set forth in, e.g., U.S. patent application Ser. No. 08/761,575, previously incorporated herein by reference, and commonly assigned U.S. Patent Application Serial No. 60/086,240, filed Apr. 4, 1997, also incorporated herein by reference in its entirety.
EXAMPLES
Example 1
Fluid Direction in a Polymethylmethacrylate Substrate (PMMA)
Microfluidic devices were fabricated in polymethylmethacrylate (PMMA) using various methods, including: (1) casting a polymer precursor against the inverted replica of the channel geometry; and (2) embossing a solid sheet of PMMA against the inverted replica by applying suitable temperature and pressure.
An inverted replica of a microfluidic device having the channel geometry shown in FIG. 2, was fabricated from silicon using inverted lithography, i.e., etching away the surface everywhere except where the channels were to be located. This was done with an anisotropic etch (hot KOH) so that the sidewalls of the raised channels were planes at an angle of 55°. The resulting raised channels were 10.87 μm high.
A polymethylmethacrylate polymer was cast against the above-described silicon mold, and this casting was bonded to another planar piece of PMMA which had holes drilled through it to provide the sample and reagent wells. Bonding was carried out by applying pressure and temperature of 98° C. The resulting device was used for subsequent analysis.
In order to demonstrate the ability to switch electroosmotic flow in a PMMA device, and to measure the magnitude of that flow, the above described device was filled with 100 mM borate buffer, at pH 7. A neutral marker, Rhodamine B, diluted in running buffer, was aliquoted into reservoir 226 (as referenced in FIG. 2 ). The neutral marker is fluorescent to allow for its detection, and uncharged, so that it will move with the flow of buffer, and thus indicate electroosmotic flow of the buffer, rather than electrophoretic mobility of the marker.
The running protocol flowed the rhodamine dye from reservoir 226 to reservoir 228 , across the intersection of channels 222 / 224 and channel 204 (injection point) prior to injection. Sample flow was detected, not at detection window 230 , but instead, at a point in the main channel 3.25 mm from the injection point, before the channel turns towards reservoir 216 .
Detection of rhodamine was carried out using a Nikon inverted Microscope Diaphot 200, with a Nikon P101 photometer controller, for epifluorescent detection. An Opti-Quip 1200-1500 50W tungsten/halogen lamp coupled through a 10× microscope objective provided the light source. Excitation and emission wavelengths were selected with a DAPI filter cube (Chroma, Brattleboro Vt.) fitted with an appropriate filter.
In this experiment, the total path length between reservoirs 208 and 216 , along which the running voltage was applied, was 52 mm. The voltage applied along this channel was 1200 V, yielding an electric field of 235 V/cm. Rhodamine B sample plugs at the injection point were injected at 400 second intervals. A plot of fluorescent intensity detected at the detection point vs. time is shown in FIG. 3 .
The time needed for the sample to travel the 3.25 mm from the injection point to the detection point was 85 seconds, translating to a velocity of 3.8×10 −3 cm/s. It was therefor concluded that the electroosmotic mobility of the buffer under these conditions was 1.6×10 −5 cm 2 /Vs.
Example 2
Electroosmotic Flow in Injection Molded PMMA Substrate
A similar experiment to that described above, was performed in a microfluidic device having a single channel connecting two reservoirs or wells. In this experiment, the device was fabricated by injection molding the first planar substrate using PMMA (Acrylite M30), which defined the channel of the device, and bonding a drilled second planar PMMA substrate to seal the channels and provide the reservoirs. Again, bonding was done with pressure at elevated temperatures, e.g., 85° C. and 2-5 kg pressure.
The channel and reservoirs of the device were filled with 10 mM sodium borate running buffer, at pH 8.0, and Rhodamine was additionally placed in one reservoir. 2000V were applied to the rhodamine containing reservoir with 1500V applied to the other reservoir. This yielded an applied voltage of 500V along the channel connecting the two wells. Detection was carried out at a point in the channel, 2.2 cm from the rhodamine containing reservoir. Transit time for the dye from its reservoir to the detection point was 187 seconds and 182 seconds in duplicate runs, yielding an average μEO of 5.25×10 −5 cm 2 V −1 s −1 .
While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be clear to one stilled in the art from a reading of this disclosure that various changes in form and detail can be made without departing from the true scope of the invention. All publications and patent documents cited in this application are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication or patent document were so individually denoted. | Microfluidic devices are provided for the performance of chemical and biochemical analyzes, syntheses and detection. The devices of the invention combine precise fluidic control systems with microfabricated polymeric substrates to provide accurate, low cost miniaturized analytical devices that have broad applications in the fields of chemistry, biochemistry, biotechnology, molecular biology and numerous other fields. |
BACKGROUND OF THE INVENTION
The present invention relates to a method for suppressing resonance phenomena in the a-c network on the inverter side of a high-voltage d-c transmission system (HVDCTS). The invention further relates to an apparatus for carrying out the method.
With reference to FIG. 1, an HVDCTS is shown which is arranged between two a-c networks NA, NB and in which a first converter 1A of the HVDCTS which is connected in a first station (STA) to the first a-c network NA, is clocked by the network and is operated as a rectifier, impresses a predetermined d-c current i dA from the first a-c network and in a second station (STB), a second converter 1B which feeds into the second a-c network NB, is clocked by the network and is operated as an inverter, determines the level U dB of the transmitted d-c voltage.
In the preferred embodiment shown of a short coupling, the two stations are physically close together and the HVDCTS comprises only the d-c lines 2 and 3, a converter choke LA and LB being arranged at the d-c terminal of each converter. Each station contains a regulator 4A, 4B, the output signal of which determines, as the control voltage Δx A , Δx B , respectively, the control angle for the control unit STA and STB of the respective converter. The control units can be supplemented in the case of a digital control unit by supplementary devices, not shown, for instance, for linearizing the characteristic and/or for converting the given analog control voltage into a digital signal in the case of a digital control unit.
The control voltage Δx A determines the d-c voltage U dA at the d-c terminal of the converter 1A and therefore, if the d-c current i dA is set into the regulator 4A (current regulator), the control deviation of the d-c current fed-in by the converter 1A, the transmitted HVDCTS d-c current i d which is equal to the d-c current i dB which is taken from the converter 1B of the HVDCTS and is fed into the network NB, since in the case of a short coupling, power losses occurring in thyristors and chokes can be ignored (i d =i dA =i dB ). To the regulator 4B of station B (for instance, a voltage regulator or quenching angle regulator) can be fed, in the interest of holding the voltage of the network NB constant, the control deviation of the voltage amplitude of this network or, in the interest of an efficiency as high as possible for the power transmission and low reactive power, the control deviation of the quenching angle of the converter 1B can be pre-set by a predetermined designed quenching angle value which is a maximum as far as possible (i.e., is close to the inverter out-of-step limit). Its control voltage Δx B determines the d-c voltage U db associated with the impressed HVDCTS current i d at the d-c terminals of the converter 1B and thereby, the voltage level U d of the transmitted d-c voltage which is taken off between the two converter chokes LA and LB and, in the case of a long distance HVDCTS line, preferably at the end of the choke LA facing away from the converter 1A.
The two stations are coupled to each other via the HVDCTS in such a manner that any change of Δx B and U dB in station B causes, in accordance with the voltage drop at the HVDCTS, a change of U dA and thereby, a current change in station A which must be equalized by the current regulator 4A. On the other hand, any change of Δx A or U dA in the station A brings about a change of i d and U dB in station B, to which the regulator 4B responds in station B. In order to keep interfering effects of this coupling as low as possible, it has already been proposed to impress on the output signal Δx A of the current regulator 4A a pilot voltage U dAv , which is taken off directly at the measuring stage for U d or is formed by means of a computing circuit as the model variable. Likewise, a pilot voltage U dBv can be impressed on the control voltage Δx B , which is formed in a different manner, for instance, by calculating the inductive d-c voltage drop of the converter 1B.
For the network NB, the HVDCTS operates in practice so that the voltage oscillations are reflected at the converter, wherein a small ripple of U d and i d is produced which is equalized by the current regulator 4A if this current regulator works fast enough. In FIG. 1, it is indicated that the network NB can contain a disturbing voltage oscillation which in this manner acts like an oscillation coupled into the HVDCTS circuit via an interference quantity U B for the control angle Δx B with a generally changed amplitude, phase and frequency.
If in the network, this interfering oscillation is located in the vicinity of the resonance frequency of the network and if the current regulator 4A is not able to equalize the resonance frequency generated in the d-c circuit, this interfering oscillation can thereby be fanned-up in such a manner that considerable ripple of U d and i d in the HVDCTS circuit comes about, in which the d-c voltage corresponding to the nominal voltage provided is superimposed by a "resonance oscillation" which can exceed, for instance, 30% of the nominal voltage and can ultimately lead to the situation that the entire system must be shut down. This is the case, for instance, in a specific case, in which the resonance frequency of the network NB is in the vicinity of the second harmonic of the network NB, it having been found that the interfering resonance frequency of the d-c circuit is approximately equal to the fundamental (60 Hz) of the 3-phase network NB.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to suppress such a resonance phenomenon in an HVDCTS between the a-c voltage on the inverter side and the transmitted d-c voltage or the transmitted d-c current.
The basic idea of the invention is to determine the resonance phenomenon (in the example, therefore, the 60Hz oscillation) in the d-c circuit and to attenuate it by intervention into the control of the rectifier station. Since the control 4A of this station is as a rule, too sluggish for this purpose, a control variable corresponding to the resonance phenomenon is applied as a pilot voltage ΔU A of (possibly already servo-controlled by the pilot voltage U dAv ) control voltage Δx A at the output of the regulator 4A. While thereby the resonance oscillation in the d-c circuit is ultimately also coupled into the network NA, the resonance frequency of the network NA is almost always different from the resonance frequency of the network NB, and in addition, the phase and frequency of the network NA always changes somewhat relative to the network NB, further resonance phenomena in the network NA do not come about, while the resonance of the network NB can be damped effectively.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explained in greater detail, in the following detailed description with reference to the drawings, in which:
FIG. 1 is a block diagram of the present invention; and
FIG. 2 is a graph showing signals present in the diagram of FIG. 1.
DETAILED DESCRIPTION
If the operating point of station B, particularly the interfering frequency and the voltage U dB (or the voltage U d or the current i d caused thereby) are known well enough and if the actual value of the HVDCTS voltage U d is determined without delay and the change of the control angle of the first converter can be adjusted without delay, it would be sufficient to filter out ("isolate") the resonance oscillation component (in the example, therefore, the 60Hz oscillation) from the HVDCTS voltage U d without phase shift. If then the isolated oscillation component is added to the control voltage with amplification tuned to the operating point, it can be achieved thereby that the output voltage U dA is changed proportionally to and in phase with the HVDCTS volta U d and a constant i d =i dA is thereby impressed on the choke LA. The HVDCTS then reflects for all practical purposes no longer the interference oscillation contained in the network NB but it becomes permeable therefor and the cause of the resonance oscillation is thereby largely eliminated and the resonance is damped.
In principle, the same can be achieved if the resonance oscillation component of the HVDCTS current i d is filtered out and is added as a pilot variable to Δx A . However, the current i d follows the change generated by a periodic change of the control angle controlling the converter 1A with a respective phase shift of 90° so that a phase rotation of 90° can be produced between the pilot quantity derived from i d and the change of the control angle due to the pilot quantity.
The idealizing conditions (particularly determination and adjustment of the voltage U d without delay and filtering out the resonance oscillation component without phase rotation) do not exist, however, in reality. Thus the measuring transformers which are required for determining and stepping down the high voltage U d have a considerable time constant which is frequently increased still further by additional smoothing. Also the control unit of the converter 1A exhibits a switching delay and additional smoothing. The control circuit which leads from the measuring transformer for determining the oscillation component to the actual value of the oscillation component via the addition of the pilot variable derived from the oscillation component, therefore has a time constant ("time constant of the pilot") which must be taken into consideration in order to produce the desired phase equality of U dA and U d .
On the other hand, filtering out the oscillation component which is superimposed on the d-c voltage or the d-c current in the HVDCTS d-c circuit is as a rule possible only with phase rotation. This, however, can be utilized for equalizing through appropriate design of the required filter circuit, just that time constant of the pilot, i.e., the phase angle belonging to this time constant and to the frequency of the resonance oscillation. The filter circuit for determining the measured value is therefore tuned to this phase angle φ. Thereby, however, heavy damping is possible only for a given operating point. If therefore only one pilot quantity is formed, the design of the filter circuit (phase rotation and gain) must follow the change of the operating point in the event of a change of the operating point in order to obtain optimum damping also in the case of a change of the amplitude of U d or i d or of the frequency of the resonance oscillation.
If, in addition, the pilot quantity is derived from the d-c current i d , it must be added that this pilot quantity damps just that oscillation of i d which is required for forming the pilot quantity itself. Thus, the better the damping is to be, so much more difficult becomes the determination of the damping pilot quantity.
These difficulties are avoided if both measures are combined with each other. It is then sufficient to use for the formation of the control input derived from the measured voltage value a filter circuit which is tuned to a central operating point. Any deviation of the actual operating point from this mean operating point then means a detuning of the resonance conditions corresponding to overcompensation or undercompensation of the resonance oscillation, from which a resonance oscillation in the measured current value follows. From this current resonance can then be formed a further pilot quantity, with gain, by a phase rotation which amounts to about 90°. By the addition of the total pilot quantity resulting as the sum of both pilot quantities, an optimum damping for operating points variable within a wide operating range can be achieved with constant lay-out of the circuit.
In this connection it has been found that the tuning of the filter circuit for the measured current value is not very critical. In particular, it is frequently not necessary to take also into consideration the phase angle due to the mentioned time constant of the pilot for the phase rotation of the current resonance oscillation component beyond the 90° phase shift.
In the embodiment of FIG. 1, the filter circuit 10 is realized by a bandpass filter 101 tuned to the mean resonance frequency of the d-c circuit, i.e., 60 Hz, with a following amplification stage 102. This bandpass filter accordingly isolates this frequency of the d-c circuit from the d-c component and the harmonics caused by the converter operation, and brings about at the same time the desired phase shift by the angle φ.
Any deviation from the operating point on which the filter circuit 10 is based makes it necessary that the current i d has ripple. Depending on how, for instance, the d-c voltage U d or the frequency of NB is changed, overcompensation or undercompensation of the resonance of the network can result by the output voltage U' d of the filter circuit 10.
It is therefore provided advantageously to form also a quantity i' d determining the d-c current i d and to impress the control voltage Δx A in such a manner that thereby the over-or undercompensated oscillation of the d-c voltage U d is coupled with positive or negative feedback to an additional oscillation corresponding to the current resonance.
For this purpose, also the resonance oscillation contained in the measured value i d of the HVDCTS is isolated with a phase rotation of about 90°, is amplified suitably and is impressed on the control voltage Δx A together with U' d . Filtering out the current resonance frequency and its phase rotation is preferably realized in the filter circuit 11 of the arrangement by forming the derivative d/dt (i d ) of the d-c current, where the differentiator 111 can be followed by a smoothing member 112 with little smoothing. Furthermore, an amplifier 113 is connected thereto. The two filter circuits 10 and 11 are tuned to each other and to the operating range of the HVDCTS in such a manner that optimum smoothing is achieved practically for all occurring operating points.
According to FIG. 1, it is further provided advantageously to execute the damping addition of the pilot quantity U A only if a disturbing resonance occurs in the network NB and thereby, a noticeable resonance in the d-c circuit. Therefore, a filter tuned to the interfering resonance frequency (in the example, 60 Hz) of the d-c circuit for the measurement value of U d (or preferably of i d ) is provided which isolates the resonance frequency, forms its amplitude via a rectifier 122 and feeds the latter to a threshold member 123. If the resonance amplitude exceeds a predetermined critical threshold value, a time delay member 124 is triggered which drives a transistor switch 125 into conduction. The switch 125 then adds during this intervention time the damping pilot quantity ΔU A to the control voltage, while the resonance phenomenon in the network NB is damped and also disappears quickly completely, depending on the network configuration.
In FIG. 2, three states of the device according to FlG. 1 are shown. First, state I will be considered, in which the two networks NA and NB contain only the respective fundamental and their voltage amplitudes are therefore proportional to the control voltage Δx A and Δx B and are therefore constant. In this undisturbed case, also the d-c voltages U d , U A and U dB as well as the d-c current i d and the transmitted active power P d are constant.
If now the resonance frequency of the network NB is equal to the second harmonic of this a-c voltage network, a corresponding oscillation is excited and is fanned-up to a considerable amplitude. This resonance oscillation generates in the measured value U d of the d-c voltage a superimposed resonance frequency with the frequency of the fundamental, which can be simulated, for instance, by the provision that the corresponding resonance oscillation ΔU B is superimposed on the control angle of the control unit 1B. With the occurrence of the resonance in the network NB, the HVDCTS changes therefore from the undisturbed state I to the resonance state II.
The current regulator 4A cannot compensate this oscillation and remains practically at its constant value. Consequently, also the d-c output voltage U dA is constant, while the d-c voltage U dB and U d exhibit the oscillation generated by ΔU B . Corresponding to the voltage difference U dA -U dB , a resonance frequency is also produced in the d-c current i d , so that the transmitted active power P d contains considerable pulsations. The HVDCTS therefore becomes permeable to a certain extent to the resonance phenomena of the network NB which are ultimately coupled into the network NA and are damped only there.
If now the pilot control variable ΔU A is formed from U d and i d , the d-c voltage U dA is now proportional to Δx A +ΔU A , where U A is now determined so that the driving voltage U dB -U dA in the HVDCTS becomes constant and thereby generates a constant d-c current i d .
By keeping the HVDCTS current constant in this manner, the permeability of the HVDCTS and therefore the damping of the resonance in NB is greatly increased and, after the switch 125 is closed, changes from state II quickly back to state I.
To better illustrate the action of the pilot quantity ΔU A better, an operating state is shown by III in FIG. 2, in which the state with the excited resonance frequency is maintained artificially by adding a further control variable ΔU B to the output of the regulator 4B in the network NB. With this simulation it can be seen clearly that in state III, the d-c voltage U dB , U d and U dA are proportional and of the same phase so that the desired constancy of the d-c current is assured. However, this is accompanied by a pulsation of the active power P d , where now the added pilot control quantity ΔU A couples a certain amount of harmonics into the network NA. Since, however, state III, in which the resonance in the network NB has a considerable amplitude and the pilot control quantity ΔU A is added, occurs only immediately after the switch 125 is closed and thus state III is assumed to be only temporary during the change from state II to state I, the pulsation of the active power and the interference frequency coupled into the network NA are practically without importance.
It becomes possible thereby to suppress a resonance phenomenon in the network NB by appropriate intervention into the control of the rectifier by practically eliminating the cause, namely, the reflection of the interference oscillation.
In the foregoing specification, the invention has been described with reference to a specific exemplary embodiment thereof. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense. | If in a high-voltage d-c transmission system (HVDCTS), a resonance frequency of an a-c voltage network (NB) connected to the inverter (1B) is located in the vicinity of a voltage component contained in the a-c voltage network, a resonance frequency which often cannot be compensated by a current regulator controlling the rectifier stage (1A) is coupled into the d-c circuit of the HVDCTS via the inverter. Therefore, resonance phenomena which requires an emergency shutdown of the HVDCTS are generated. Therefore, a pilot quantity (U' d) is formed with a defined phase shift relative to the resonance oscillation of the HVDCTS voltage and added to the output of the current regulator. Thereby, a constant HVDCTS current can be generated for a given operating point and the resonance in the a-c voltage network (NB) can be damped. If the resonance oscillation is determined by two quantities (U' d, i' d) of, respectively, the HVDCTS voltage as well as of the HVDCTS current, stable damping of the resonance phenomena can be achieved by the pilot control described with the two quantities even for deviating operating points. |
This is a divisional of application Ser. No. 09/456,838 now U.S. Pat. No. 6,357,099 filed Dec. 7, 1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the recycle of wasted metal products and, more particularly, to the preparation of metal feedstock from wasted metal products such as, for example, metallic component parts of electric products including, for example, air conditioners or refrigerators.
2. Description of the Prior Art
In the conventional recycling practice, crushed pieces of a wasted metal product are first separated into ferrous and non-ferrous materials by the utilization of magnetism and the ferrous materials so separated are, without being further sorted, charged into a cupola to produce a ferrous feedstock. To feed the ferrous materials into the cupola, the ferrous material must be in the form of bricks of a size comparable to that of a refractory brick so that the ferrous materials will not be blown up by a hot blast within the cupola.
To prepare the ferrous bricks, the ferrous materials may be pressed together by the use of, for example, a press. However, if the ferrous materials include both sheet-shaped scraps, regardless of whether flat or deformed, and cast blocks, the cast blocks often render it difficult for the ferrous materials to be pressed into the ferrous bricks. Accordingly, the magnetically separated ferrous materials have been utilized only as a low-quality scrap.
In some case, the sheet-shaped ferrous scraps are further separated from the cast blocks and pressed together for reuse as a metal feedstock. The pressed iron scraps are fed into a melting furnace such as a cupola or an electric furnace. In that case, however, after feeding the metal feedstock into the furnace, a mixture of component adjusters such as carbon, silicon, manganese, phosphorus and/or sulfur must be fed into the furnace to adjust the concentration of impurities contained in the melt within the furnace. Those component adjusters must be mixed in a mixing ratio that is determined depending on the application for which the material recycled from the metal feedstock is intended to use. By way of example, the metal feedstock is to be eventually used as a material for component parts of an electric compressor to a type generally used in air-conditioner or refrigerators, the following compositions as shown in Table 1 is required.
TABLE 1
C
Si
Mn
P
S
Ti
Sb
Cr
Cylinder
3.50
2.50
0.50
0.10
0.10
0.10
0.02
—
Shaft
3.20
2.40
0.50
0.10
0.10
—
0.02
0.50
Piston
3.20
2.40
0.50
0.10
0.10
—
0.02
0.50
Bearing
3.20
2.40
0.50
0.10
0.10
—
0.02
0.50
Since these component adjusters are relatively light-weight, they tend to float in a top layer of the ferrous melt within the furnace. The component adjusters afloat on the top layer of the melt without being well mixed in the melt are apt to be oxidized and become dross. This brings about problems associated with low efficiency of utilization of the component adjusters and increase in quantity of dust. Further, there are problems in that feeding of the adjusters is hazardous and also in that an extra process of removing the dross is required.
SUMMARY OF THE INVENTION
It is accordingly an objective of the present invention to enable the metal feedstock to be efficiently and safely prepared from wasted metal products to recycle the metal products without the efficiency of utilization of the component adjusters being lowered.
Another objective of the present invention is to provide the metal feedstock which when fed into a cupola will neither fly nor break up during falling downwardly within the cupola.
For this purpose, the present invention provides a method of and an apparatus for making the metal feedstock from the wasted metal products. According to the present invention, the metal feedstock can be prepared from wasted metal products by crushing the metal products into pieces; magnetically separating the crushed pieces into sheet-shaped ferrous scraps and ferrous cast blocks; placing the ferrous cast blocks between the sheet-shaped ferrous scraps to make a sandwich structure; and pressing the sandwich structure to form the ferrous feedstock.
According to the present invention, the sheet-shaped scraps and the cast blocks are firmly bound together to form a heavy metal feedstock. The metal feedstock will not fly up in the cupola and is efficiently utilized as a casting material.
In a preferred embodiment of the invention, the magnetically separating step includes a first-separation step separating the sheet-shaped ferrous scraps, and a second-separation step separating the ferrous cast blocks. A magnetic flux density around the crushed pieces employed during the second-separation step is preferably set at a value higher than that that during the first-separation step. This relationship assists in improving the efficiency of recovery of iron pieces and reducing the content of copper in the resultant ferrous feedstock.
In another embodiment of the invention, after the magnetical separating step, the ferrous cast blocks smaller than a predetermined size may be further separated. Since the ferrous cast blocks larger than the predetermined size can be fed into the cupola without pressing process, that further separation improves a productivity of the metal feedstock.
A weight percentage of the sheet-shaped ferrous scraps in the sandwich structure is preferably greater than 60% to prevent disassembling of the resultant metal feedstock during falling in the cupola.
In a further embodiment of the invention, content adjusters may be mixed in the sandwich structure. This eliminates the hazardous process of adding the content adjuster to the melted iron in the cupola. By combining the content adjusters with the sandwich structure, the adjusters will sink in the melted iron and will not oxidized. Thus, mixing of the content adjusters can take place smoothly and the efficiency of utilization of the adjusters can be increased.
In a second aspect of the present invention, an apparatus for forming a metal feedstock from wasted metal products comprises:
first, second and third measuring means for measuring out an amount of iron pieces, wherein said first and second measuring means are for sheet-shaped ferrous scraps and said second measuring means is for ferrous cast blocks, said scraps and blocks being obtained by crushing waste metal products;
a third measuring means for measuring an amount of the sheet-shaped ferrous scraps;
transport means for successively transporting the sheet-shaped scraps, the cast blocks and the sheet-shaped scraps that have been measured by said first, second and third measuring means respectively;
a holding means for receiving and holding the sheet-shaped scraps, the cast blocks and the sheet-shaped scraps transported by said transport means; and
a pressing means for simultaneously pressing the sheet-shaped scraps, the cast blocks and the sheet-shaped scraps in said holding means to form a cast feedstock of a sandwich structure.
According to the apparatus of the present invention, a predetermined amount of sheet-shaped scraps and cast blocks are pressed together to form a sandwich-structured cast feedstock. Thus, the apparatus of the invention is capable of recycling the wasted metal products efficiently.
The apparatus of the invention may comprise a crushing means for crushing the metal products and a separating means for separating the crushed metal products.
Preferably, the apparatus of the present invention further comprises a supplying means for supplying at least one content adjuster to the transport means. The content adjuster supplied to the transport means is mixed in the sandwich-structured cast feedstock.
In a third aspect of the present invention, a metal feedstock comprises cast blocks and sheet-shaped scraps wherein the cast blocks are disposed between the sheet-shaped scraps and pressed together to form a sandwich-structured metal feedstock. The cast feedstock is firmly bounded and heavy enough to fall in the cupola.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objectives and features of the present invention will become more apparent from description of a preferred embodiment thereof with reference to the accompanying drawings, throughout which like parts are designated by like reference numerals, and wherein:
FIG. 1 is a block diagram showing a method of forming a metal feedstock from wasted metal products according to a preferred embodiment of the present invention;
FIG. 2 is a schematic diagram showing steps of crushing and separating metal products;
FIG. 3 is a partial perspective view of an apparatus for forming the metal feedstock from wasted metal products;
FIG. 4 is a schematic diagram showing a step of pressing sheet-shaped pieces and cast blocks separated from the crushed metal products;
FIG. 5 is a perspective view of the metal feedstock that has been caked by press and has a sandwich structure;
FIG. 6 is a graph showing a magnetic flux density of a magnetic separator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The application is based on an application No. 10-357477 filed in Japan, the content of which is incorporated herein by reference.
Referring to FIG. 1, wasted metal products are crushed into iron pieces including sheet-shaped iron pieces and cast iron pieces 4 and 6 and non-iron pieces 8 . Thereafter, a magnetic separator 10 separates the iron pieces from the non-iron pieces 8 . The iron pieces are then fed into a melting furnace such as a cupola or an electric furnace to recycle the iron pieces as a metal feedstock.
Respective steps of crushing and separating the wasted products are shown in FIG. 2 . The wasted products are fed in a crusher 2 and are crushed into the iron and non-iron pieces. These crushed pieces are transported below a first magnetic separator 12 and a second magnetic separator 14 by means of a vibrating conveyer 10 so that the crushed pieces can be separated into the sheet-shaped scraps 4 , cast blocks 6 and non-iron scraps 8 .
The first separator 12 attracts only the sheet-shaped scraps 4 from the crushed pieces, the rest of which, i.e., the cast blocks 6 and the non-iron pieces 8 are further transported toward the second magnetic separator 14 by means of the conveyer 10 (first magnetic separation). The second separator 14 attracts mainly the cast blocks 14 (second magnetic separation). The non-iron pieces 8 that have not been attracted by the separator 14 fall down from the conveyer 10 .
The magnetic force of the second separator 14 is set to a value greater than that of the first separator 12 so that the second separator 14 can attract all the iron pieces that have not been attracted by the first separator 12 .
The various size of pieces attracted by the second separator 14 are divided into two groups by a size-selecting means such as a sieve or a magnetic separator: one group includes pieces larger than a predetermined size, for example, 20 mm square, and the other group includes pieces smaller than that size. The first group of the iron pieces are directly fed into a cupola. On the other hand, the second group of the iron pieces are pressed with the sheet-shaped scraps 4 , separated by the first separator 12 , because the pieces smaller than the predetermined size tend to be blown up by an uprising blast within the cupola.
Referring to FIG. 3, a sandwich-press apparatus 15 , which forms a metal feedstock from the sheet-shaped scraps 4 and the cast blocks 6 , includes a first hopper 16 for receiving the iron scraps 4 , a second hopper 18 for receiving the iron blocks 6 and a third hopper 20 for receiving the iron scraps 4 . A first, second and third weighing conveyer 22 , 24 and 26 are placed immediately beneath outlets of the first, second and third hopper 16 , 18 and 20 , respectively. A supplying conveyer 28 is placed under respective downstream ends of the weighing conveyers 22 , 24 and 26 . A supplying chute 30 is placed under a downstream end of the supplying conveyer 28 . An outlet of the supplying chute 30 is connected to a barrel 32 a , which is a part of a press 32 . An ejecting device 34 is placed under the press 32 to eject a sandwich-like feedstock eventually formed by the press 32 .
The operation of the sandwich-press apparatus 15 will be described. Among the pieces crushed and separated by the apparatus in FIG. 2, the sheet-shaped scraps 4 are fed into the first and third hopper 16 and 20 . The cast blocks 6 smaller than the predetermined size are fed into the second hopper 18 . The iron pieces received by the hopper 16 , 18 and 20 are weighed and carried toward the supplying conveyer 28 by the weighing conveyers 22 , 24 and 26 , respectively. Then, the iron pieces received by the supplying conveyer 28 are successively delivered to the barrel 32 a through the supplying shoot 30 in the order of the iron scraps 4 , the iron blocks 6 and the iron scraps 4 . The iron pieces loaded in the barrel 32 a are pressed by a piston 32 b connected to a cylinder 32 c to thereby produce a metal feedstock. Then, the resultant metal feedstock is ejected from the press 32 by the ejecting device 34 .
To describe in detail with reference to FIG. 4, a predetermined amount of iron blocks 6 , iron scraps 4 and iron scraps 4 are stacked one above the other with the iron blocks 6 intervening between the iron scraps 4 . By pressing the layered iron pieces by the press 32 , a sandwich-structured metal feedstock 36 as shown in FIG. 5 is formed. This feedstock 36 is heavy enough to fall without flying up by the blast in the cupola.
The sandwich-press apparatus 15 may include an adjuster hopper that receives the component adjuster. The received component adjuster is weighed and a predetermined amount thereof is fed on the supplying conveyer 28 between the iron scraps 4 fed by the conveyer 22 and that fed by the conveyer 26 . Then, the component adjuster is pressed with the iron blocks 6 between two layers of the iron scraps 4 . Thus, the component adjuster can be inserted into the feedstock.
Among five impurity elements in a cast iron (C, Si, Mn, P and S), Si and Mn are usually available as 50 mm-in-diameter grains and may be fed directly into the adjuster hopper. On the other hand, since C, P and S are usually available as 5 mm-in-diameter grains or 1˜2 mm particles, they may be fed in a sack such as a paper bag. Other elements such as Ti, Sb or Cr may be fed in a similar manner: Large grains are directly fed into the hopper and small grains or particles are fed in a suck.
Hereinafter a specific example of the method of the present invention will be described.
In this example, the wasted metal product is an electric compressor used in an air-conditioner outdoor unit. The crusher 2 , the first and the second magnetic separator 12 and 14 , the vibrating conveyer 10 and the press 32 are as follows:
Crusher 2:
Standard capability,
5 T/H
Drive motor,
90-132 kW
Inlet size (width × depth),
900 × 1200 mm
Magnetic separators 12 and 14:
Type,
permanent magnet type
Magnet,
anisotropic strontium ferrite magnet
Surface magnetic flux density,
800 gauss
Magnet size,
320 mmW × 100 mmH × 1800 mmL
Vibrating conveyer 10;
Vibration amplitude,
16 mm
Frequency,
520 cpm
Press 32;
Pressing pressure,
300 kg/cm 2
The compressor was detached from the outdoor unit of the air conditioner. After cutting off an accumulator from the compressor, oil in the compressor body and in the accumulator was removed. Copper pipes attached to the compressor were cut away to reduce a blending of copper into an eventually formed metal feedstock 36 . The copper content in the feedstock 36 should be under 0.1% to provide an ease to cut the metal feedstock 36 .
The output-gate height of the crusher 2 was set as 30 mm to prevent a crushed motor coil (a copper wire) from winding around the iron scraps. The compressor body and the accumulator were then thrown into the crusher 2 . By passing them under the first and second magnetic separator 12 and 14 while transporting by means of the vibrating conveyer 10 , the iron scraps 4 and the iron blocks 6 were separated therefrom. The distance from the conveyer 10 to the first separator 12 was set to 220-240 mm and that to the second separator 14 was set to a value smaller, for example, as about 150 mm, so that the iron scraps 4 were selectively attracted by the first separator 12 and the iron blocks 6 were attracted by the second separator 14 . In the case the distance to the first separator 12 was set to 150 mm, since the magnetic induction was too large, the iron scraps 4 were attracted together with the iron blocks 6 and could not separated selectively.
A magnetic flux density measured on the conveyer 10 is shown in Table 2, where the distance from the conveyer to the magnetic separator was 150 mm, 220 mm or 240 mm. Table 2 also shows a horizontal distribution of the magnetic flux density. Table 2 is graphed out in FIG. 6 . These data and the experimentation described above indicate that the first separator's magnetic flux density on the conveyer 10 should be below about 200 gausses.
TABLE 2
*1
*2
200
300
400
500
600
700
800
900
1000
1100
1200
1300
240
79
85
82
76
71
66
65
58
53
45
34
25
220
130
146
145
141
138
135
134
132
130
123
104
69
150
161
278
278
264
260
255
253
246
244
233
293
102
/gauss
*1 a horizontal distance from the end of the magnetic separator (mm)
*2 a vertical distance from the conveyer to the magnet (mm)
The separated iron blocks 6 were further separated into two groups by a sieve: one group was over 20 mm in size and the other was under 20 mm. The blocks in the latter group were stacked with the iron scraps as shown in FIG. 4 and then pressed. A disc-shaped metal feedstock 36 as shown in FIG. 5 was thus formed. The size of the feedstock 36 was 130 mm (in diameter)×49 mm (in thickness) and the weight was about 2 kg.
It is needless to say that the larger the weight ratio of the scraps 4 to the blocks 6 is, the firmer the feedstock becomes. However, even where the weight ratio of the scraps to the blocks was only 6 to 4, the sandwich-structured disc kept assembled while falling and was usable as a feedstock. Where the ratio was 5 to 5, some of the discs disassembled while falling. However, in the case the scraps had elongated shape and was easily deformable, the scraps and the blocks could be combined even in the ratio of 2 to 8.
Although both the magnetic separators 12 and 14 used in this example have permanent magnets, a magnetic separator with an electromagnet may also be used.
If the multi-step-type conveyer is used as the conveyer 10 to drop the crushed pieces at the steps, a tangling of the crushed pieces is reduced and thus, for example, a copper content is efficiently lowered.
Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted here that various changes and modifications will be apparent to those skilled in the art. Therefore, unless such changes and modifications otherwise depart from the spirit and scope of the present invention, they should be constructed as being included therein. | An apparatus for forming a metal feedstock from waste metal products is disclosed. The apparatus includes devices for: crushing the metal products into pieces; magnetically separating sheet-shaped ferrous scraps and ferrous cast blocks from the crushed pieces; placing the cast blocks between the sheet-shaped scraps to make a sandwich structure; and pressing the sandwich structure to form a metal feedstock. |
CLAIM OF PRIORITY
[0001] This application is a Divisional Application of U.S. Non-Provisional application Ser. No. 14/057,275, filed Oct. 18, 2013, which claims priority to U.S. Provisional Patent Application No. 61/716,203, filed Oct. 19, 2012, the contents of which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present technology relates to work stations for use in applying pulling heads to the ends of wires that have been wound onto a single reel for installation into a conduit.
DESCRIPTION OF RELATED ART
[0003] Pulling heads have been developed that allow multiple cables, sometimes referred to as wires or conductors, to be simultaneously pulled through a conduit. Such pulling heads include a plurality of lugs attached to lanyards of varying lengths, and the lanyards all attach to a single pulling head. A pulling rope running through the conduit is attached to a pulling head, which is in turn attached to each cable by separate pulling lugs, and the rope is pulled through the conduit, drawing the multiple conductor cabling from spools or other delivery mechanism and through the conduit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Specific examples have been chosen for purposes of illustration and description, and are shown in the accompanying drawings, forming a part of the specification. The drawings are not drawn to scale. Accordingly, the dimensions or proportions of particular elements, or the relationships between those different elements, as shown in the drawings are chosen only for convenience of description, but do not limit possible implementations of this disclosure. Like numerals represent like elements throughout the several figures.
[0005] FIG. 1 is a top plan view of an embodiment a pulling head work station of the present technology.
[0006] FIG. 2 is a side elevational view of a stripper that can be used with a pulling head work station of FIG. 1 .
[0007] FIG. 3 is a perspective view of a crimping head that can be used with a pulling head work station of FIG. 1 .
[0008] FIG. 4 is a perspective view of a plurality of cables placed into cable receiving jigs of the pulling head work station of FIG. 1 .
[0009] FIG. 5 is an end elevational view of a cable receiving jig of the pulling head work station of FIG. 1 .
[0010] FIG. 6 is a top plan view of a portion of a cable receiving jig of the pulling head work station of FIG. 1 .
[0011] FIG. 7 is an end elevational view of cable receiving jigs of the pulling head work station of FIG. 1 , in an open position and in a clamped position.
[0012] FIG. 8 is a top plan view of a single cable being fed to the pulling head work station of FIG. 1 .
[0013] FIGS. 9A-9C are top plan views illustrating one of the cables of FIG. 8 being fed into a cable receiving jig of the pulling head work station of FIG. 1 .
[0014] FIG. 10 is a top plan view of the pulling head work station of FIG. 1 , with the chop saw in a first position.
[0015] FIG. 11 is a top plan view of the pulling head work station of FIG. 1 , with the chop saw in a second position.
[0016] FIG. 12 is a top plan view of the pulling head work station of FIG. 1 , with the chop saw in a third position.
[0017] FIG. 13 is a top plan view of the pulling head work station of FIG. 1 , with the chop saw in a fourth position.
[0018] FIG. 14 is a top plan view of an embodiment of a chop saw that can be used with the pulling head work station of FIG. 1 illustrating alternative positions.
[0019] FIG. 15 is a top plan view of the chop saw of FIG. 14 illustrating movement between the alternative positions of FIG. 14 .
[0020] FIG. 16 is a top plan view of the pulling head work station of FIG. 1 , with the chop saw in a rest position.
[0021] FIG. 17 is a top plan view of the pulling head work station of FIG. 1 , with the stripper of FIG. 2 in use.
[0022] FIGS. 18A-18C are side elevational views of a pulling lug that can be used with the present technology being placed onto the stripped end portion of a cable.
[0023] FIGS. 19A-19C are side elevational views of the stripper of FIG. 2 being used to strip an end portion of a cable.
[0024] FIG. 20 is a perspective view of the crimper of FIG. 3 being positioned with respect to a pulling lug on a cable.
[0025] FIG. 21 is a perspective view of the crimper of FIG. 20 in place with respect to the pulling lug on a cable.
[0026] FIG. 22 is a perspective view of the crimper of FIGS. 20 and 21 crimping the pulling lug onto the cable.
[0027] FIG. 23 is a perspective view of the crimper of FIGS. 20-22 being removed from the cable.
[0028] FIG. 24 is a top plan view of the pulling head work station of FIG. 1 with the chop saw in a retracted position and the crimper in use.
[0029] FIG. 25 is a perspective view of a pulling lug crimped onto a cable after use of the present technology.
[0030] FIG. 26 is a perspective view of a reel with cables having pulling lugs attached thereto after use of after use of the present technology.
DETAILED DESCRIPTION
[0031] FIG. 1 illustrates an embodiment of a pulling head work station 100 of the present invention. The pulling head work station 100 includes a base 102 having a work surface 104 . The work surface 104 is preferably horizontal and level. The additional components of the pulling head work station 100 are mounted on the base 102 of the pulling head work station 100 . The pulling head work station 100 can include a plurality of cable receiving jigs 106 a - 106 d mounted to the work surface 104 of the base 102 . Each cable receiving jig can have a first end 108 and a second end 110 . A first cable clamp 112 a - 112 d can be mounted at the first end 108 of each cable receiving jig 106 a - 106 d, and a second cable clamp 114 a - 114 d can be mounted at the second end 110 of each cable receiving jig 106 a - 106 d.
[0032] As illustrated in FIG. 1 , the length of cable receiving jig 106 a is less than the length of cable receiving jig 106 b. The length of cable receiving jig 106 b is less than the length of cable receiving jig 106 c. The length of cable receiving jig 106 c is less than cable receiving jig 106 d. As a result, while jig first ends 108 are in horizontal alignment, the jig second ends 110 are staggered (i.e. not in horizontal alignment with one another). As explained below, this permits the cables to be automatically and conveniently cut in a staggered fashion after they are clamped in the jigs 106 a - 106 d.
[0033] It should be noted that while four jigs are illustrated in the figures and described below, the work station could feature an alternative number of jigs and associated components.
[0034] In methods of the present technology, a reel 200 including at least one cable 202 a can be provided, and the pulling head work station 100 can be used to attach a pulling lug 300 a - 300 c to each cable 202 a - 202 d. To that end, the pulling head work station 100 can include a number of tools that can be used to cut cables 202 a - 202 d , strip the end portions 204 of the cables 202 a - 202 d, and secure pulling lugs 300 a - 300 c to the stripped end portions 204 of the cables 202 a - 202 d. For example, the pulling head work station 100 can include a chop saw 116 slidably mounted to the base 102 via track 103 , a stripper 118 removably mounted to the base 102 , and a crimping head 120 slidably mounted to the base, also by track 103 . The track 103 is mounted to the work surface 104 of the base 102 .
[0035] The pulling head work station 100 can also include a power supply system 500 that supplies power to at least one of the chop saw 116 (via line 504 ), the stripper 118 and/or the crimping head 120 (via line 502 ). In one example, the power supply system 500 can include a self contained power source, such as a battery, that provides power to the work station tools. In another example, power supply system 500 can include a power cord that can connect to an electrical outlet to transfer power to the power supply system 500 . In a third example, a power supply system 500 could include both a self-contained power source and at least one power cord, to ensure that power can be provided to the power supply system 500 under various circumstances.
[0036] FIG. 2 illustrates one example of a stripper 118 that can be used with a pulling head work station 100 . The stripper 118 can be a portable device, and can be removably mounted to the base 102 of the pulling head work station 100 . The stripper can be a cordless device, which can be electrically connected to the power supply system 500 to be recharged when it is mounted to the base 102 of the pulling head work station 100 . Alternatively, the stripper 118 can include a power cord that is connected to the power supply system 500 .
[0037] FIG. 3 illustrates one example of a crimping head 120 that can be used with a pulling head work station 100 . The crimping head 120 can be slidably mounted to the base 102 of the work station 100 via track 103 and a carriage. As will be explained in greater detail below, in the illustrated embodiment, the crimping head 120 is slidable in two directions with respect to the work surface 104 , such as lengthwise and across within the plane defined by the X and Y arrows of FIG. 1 . The crimping head 120 is also illustrated as being mounted to the base 102 of the work station in parallel with the chop saw 116 .
[0038] FIGS. 4-7 illustrate a plurality of cables 202 a - 202 d placed into cable receiving jigs 106 a - 106 d of the pulling head work station 100 and clamped with first clamps 112 a - 112 d ( FIG. 1 ) and second clamps 114 a - 114 d. As illustrated, the cable receiving jigs 106 a - 106 d can be mounted parallel to each other with the ends 110 featuring a staggered configuration due to the differing lengths of jigs 106 a - 106 d . Additionally, as shown in FIGS. 5 and 7 , each cable receiving jig 106 can have a V-shaped cross section.
[0039] FIG. 7 illustrates second clamps 114 a and 114 b in a clamped position and in an open position, respectively. Each of the first clamps 112 a - 112 d and second clamps 114 a - 114 d has an open position and a clamped position, and can function in the same manner illustrated in FIG. 7 .
[0040] A method of using a pulling head work station 100 of the present technology can include placing a portion of each cable 202 a - 202 d onto a corresponding cable receiving jig 106 a - 106 d mounted to the work surface 104 of a pulling head work station 100 . As discussed above, each cable receiving jig 106 a - 106 d can have a first end 108 and a second end 110 . The method can also include clamping the placed portion of each cable 202 with a first cable clamp 112 mounted at the first end 108 of each cable receiving jig 106 and a second cable clamp 114 mounted at the second end 114 of each cable receiving jig 106 .
[0041] After the cables 202 a - 202 d are clamped into their corresponding jigs 106 a - 106 d, the method can include cutting each cable 202 a - 202 d to a desired length using a chop saw 116 slidably mounted to the pulling head work station 100 to produce a cut cable.
[0042] The method can then include removing at least one cable layer, such as the cable jacket and/or insulation, from an end portion 204 of each cut cable with a stripper 118 removably mounted to the pulling head work station 100 .
[0043] Once the end portion 204 of the cable is stripped, a pulling lug 300 can be placed onto each stripped end portion 204 . The method can then include crimping a pulling lug 300 onto each end portion 204 using a crimping head 120 slidably mounted to the base 102 . Once the pulling lugs have been secured to the cables 202 by crimping, the method can include unclamping each cable 202 from each cable receiving jig 106 .
[0044] FIGS. 8 and 9 illustrate placing a portion of each cable from roll 200 onto a cable receiving jig 106 a - 106 d, and clamping the placed portion of each cable with a first cable clamp 112 mounted at the first end 108 of each cable receiving jig 106 a - 106 d and a second cable clamp 114 mounted at the second end 110 of each cable receiving jig. Specifically, as shown in FIGS. 9A-9C , a cable 202 a can be fed into a cable receiving jig 106 a of a pulling head work station 100 , in the direction of the arrows 203 and 205 of FIG. 9B as illustrated, and then clamped by clamping each of the first clamp 112 a and second clamp 114 a.
[0045] FIGS. 10-16 illustrate one example of use of the chop saw 116 to cut, in serial, each cable 202 a - 202 d to a desired length. As illustrated in FIG. 10 , the chop saw 116 can be positioned with respect to a first cable 202 a via a track 103 and a carriage 105 to cut the cable. The carriage 105 of FIG. 10 slides along the track 103 in the direction of arrows 207 . Furthermore, the chop saw 116 is mounted at one end of slide bar 107 . Slide bar 107 slides with respect to the carriage 105 in the directions indicated by arrows 209 of FIG. 10 .
[0046] As a result, as illustrated in FIGS. 11-15 , the chop saw 116 can be repositioned with respect to a second cable 202 b, a third cable 202 c, and a fourth cable 202 d by sliding it incrementally in a lengthwise and a crosswise direction with respect to the work surface 104 of the pulling head work station 100 via track 103 , carriage 105 and slide bar 107 . As noted previously, the cables are automatically and conveniently cut to the desired lengths in a staggered fashion due to the staggered configuration of the ends 110 of the jigs 106 a - 106 d.
[0047] As illustrated in FIG. 16 , once each cable 202 a - 202 d has been cut to a desired length, the chop saw 116 can be returned to a rest position.
[0048] FIGS. 17-19 illustrate removing at least one cable layer from cable 202 d , such as the cable jacket and/or insulation, from an end portion 204 d of cut cable 202 d with a stripper 118 , and placing a pulling lug 300 d onto the stripped end 204 d of cable 202 d. A similar procedure is followed for cables 202 a - 202 c (of FIG. 17 ).
[0049] FIGS. 20-25 illustrate crimping a pulling lug 300 d onto the end portion of cut and stripped cable 202 d using the crimping head 120 . As illustrated in FIG. 24 , the crimping head 120 can be positioned with respect to cable 202 d via a track 103 and a carriage 111 to cut the cable. The carriage 111 of FIG. 24 slides along the track 103 in the direction of arrows 215 . Furthermore, the crimping head 120 is mounted at one end of slide bar 113 . The slide bar 113 slides with respect to the carriage 111 in the directions indicated by arrows 217 of FIG. 24 .
[0050] As a result, as shown in FIGS. 20-21 , the crimping head 120 can be slidably positioned, in the direction of arrow 211 in FIG. 20 , over a pulling lug 300 d that has been placed over the stripped end portion of cable 202 d. As shown in FIG. 22 , the crimping head then is activated to crimp the pulling lug 300 d onto the stripped end portion of cable 202 d, preferably in two locations, such as first crimping location 304 and second crimping location 305 illustrated in FIG. 25 . As shown in FIG. 23 , the crimping head can be slidably removed in the direction of the arrow 219 after the crimping process. A similar procedure is followed for cables 202 a - 202 c and pulling lugs 300 a - 300 c (of FIGS. 24 and 26 ).
[0051] FIG. 26 illustrates a reel 200 having a plurality of cables 202 a - 202 d after the pulling lugs 300 a - 300 d have been attached in accordance with the above.
[0052] While the preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention, the scope of which is defined by the appended claims. | A pulling head work station for attaching the lugs of pulling heads to cables, so that the cables may be pulled simultaneously through a conduit. The pulling head work station includes staggered cable receiving jigs, each jig having two clamps to hold a corresponding cable in place during attachment of a pulling lug. A chop saw to cut the cables and a crimper to secure a pulling lug to each stripped end portion of a cable may be slidably mounted to a work surface of the work station. A wire stripper may be removably attached to the work station. |
RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. §119 based on U.S. Provisional Patent Application No. 61/229,850 filed Jul. 30, 2009, the disclosure of which is incorporated by reference herein in its entirety.
BACKGROUND INFORMATION
[0002] Electrical outlet boxes are often mounted in walls prior to completion of the wall structure. For example, an electrical outlet box may be mounted on a wall stud prior to drywall installation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 illustrates an exemplary wall electrical assembly in which a supporting spacer may be used;
[0004] FIGS. 2A through 2D illustrate attaching the supporting spacer of FIG. 1 to an electrical outlet box;
[0005] FIGS. 3A and 3B are top and bottom perspective views of the supporting spacer of FIG. 1 ;
[0006] FIGS. 3C and 3D are top and side views of the supporting spacer of FIG. 1 ;
[0007] FIG. 3E is an expanded side view of legs of the supporting spacer shown in FIG. 3D ;
[0008] FIG. 4 is a flow diagram of an exemplary process for attaching the supporting spacer of FIG. 1 to the electrical outlet box of FIG. 1 ;
[0009] FIG. 5 illustrates configurations of the supporting spacer of FIG. 1 in relation to a bottom plate of the electrical outlet box of FIG. 1 , before and after the supporting spacer is attached to the electrical outlet box; and
[0010] FIG. 6 illustrates a result of attaching the supporting spacer to the electrical outlet box of FIG. 1 and mounting the electrical outlet box to a wall stud.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0011] The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements.
[0012] As described herein, a supporting spacer may be attached conveniently to an electrical box without the use of any tools. The main function of the supporting spacer is to prevent the space between the electrical box and a wall from collapsing when a force is applied to the box, such as during receptacle or drywall installation.
[0013] FIG. 1 illustrates an exemplary wall electrical assembly 100 in which a supporting spacer may be used. As shown, wall electrical assembly 100 may include drywall elements 102 - 1 and 102 - 2 , wall studs 104 - 1 and 104 - 2 , an electrical outlet box 106 , and a supporting spacer 108 . Depending on the implementation, wall electrical assembly 100 may include fewer, additional, or different components than those illustrated in FIG. 1 (e.g., a wooden stud). In addition, although electrical box can be any box associated with electrical functions (e.g., a switch box, a gang box, etc.), for the purpose of simplicity and ease in understanding, the electrical box is described in terms of electrical outlet box.
[0014] Drywall elements 102 - 1 and 102 - 2 may provide partitioning of space for occupancy of a house or building. Wall studs 104 - 1 and 104 - 2 may include vertical members of a frame to which drywall elements 102 - 1 and 102 - 2 are affixed. Electrical outlet box 106 may provide an enclosure for electrical wiring. As shown, electrical outlet box 106 is attached to wall stud 104 - 2 . Supporting spacer 108 may extend from electrical outlet box 106 to the inner surface of drywall element 102 - 2 . Being substantially rigid, supporting spacer 108 may prevent electrical outlet box 106 from moving toward drywall element 102 - 2 when a force is (e.g., an accidental push) is applied to electrical outlet box 106 in the direction of arrow 110 in FIG. 1 . This may also prevent box 106 from becoming detached from wall stud 106 - 2 , warped, or damaged.
[0015] FIGS. 2A through 2D illustrate attaching supporting spacer 108 to electrical outlet box 106 . As shown in FIG. 2A , supporting spacer 108 may include an upper body 202 and a lower body 204 . Upper body 202 may include a fastening tongue 206 , and lower body may include legs 208 and 210 . Supporting spacer 108 will be described below in greater detail with reference to FIGS. 3A-3E . Electrical outlet box 106 may include a back panel 212 in which fastening holes 214 - 1 , 214 - 2 , and 214 - 3 are provided.
[0016] To attach supporting spacer 108 to back panel 212 , legs 208 and 210 of supporting spacer 108 may be inserted into fastening holes 214 - 2 and 214 - 3 , respectively, as illustrated in FIG. 2B , by lowering supporting spacer 108 in the direction of arrow 216 . To insert fastening tongue 206 into fastening hole 214 - 1 , upper body 202 may lowered in the direction of arrow 218 without disengaging legs 208 and 210 from fastening holes 214 - 1 and 214 - 2 . In this manner, as shown in FIG. 2C , supporting spacer 108 may be placed flat against back panel 212 .
[0017] Once supporting spacer 108 is placed on back panel 212 as shown in FIG. 2C , supporting spacer 108 may be fastened to electrical outlet box 106 by raising or pivoting upper body 202 of supporting spacer 108 about a line AA (see FIG. 2C ) in the direction of arrow 220 . When upper body 202 is being raised, fastening tongue 206 (which is not visible in FIG. 2C or 2 D), may rotate about line AA along with upper body 202 .
[0018] FIG. 2D shows the result of raising upper body 202 of supporting spacer 108 . As shown, supporting spacer 108 is bent such that upper body 202 is perpendicular to back panel 212 . Moreover, in this position, fastening tongue 206 is positioned underneath and hugs the bottom surface of back panel 212 , affixing supporting spacer 108 to back panel 212 of electrical outlet box 106 .
[0019] FIGS. 3A and 3B are, respectively, top and bottom perspective views of supporting spacer 108 . FIGS. 3C and 3D are, respectively, top and bottom views of supporting spacer 108 , with exemplary dimensions. In one implementation, supporting spacer 108 may be constructed from a single piece of shapeable material, such as steel, galvanized steel, aluminum, etc. Dimensions of supporting spacer 108 may vary, depending on its components (e.g., legs 208 and 210 ), material used, and the type of electrical box to which supporting spacer 108 may be attached, etc. For the purpose of simplicity, it is assumed that supporting spacer 108 is approximately 2.25 inches (in.) long, 1.7 in. wide, and 0.032 in. thick (2.25×1.7×0.032 in.) and, may be attached to an electrical outlet box of approximately 4×4×2 in.
[0020] As shown in FIGS. 3A-3D , supporting spacer 108 may include upper body 202 , necks 302 , and lower body 204 . Upper body 202 may be connected to necks 302 , and necks 302 may be connected to lower body 204 . The dimensions of upper body 202 , necks 302 , and lower body 204 are shown in FIGS. 3C and 3D as W U ×L U , (e.g., 1.44 in.×1.16 in), W N ×L N (e.g., 0.91 in ×0.093 in), W L ×L L (e.g., 1.72 in ×0.83 in), respectively.
[0021] Upper body 202 may include fins 304 - 1 and 304 - 2 , center body 306 , fastening tongue 206 , and a tongue connecting portion 308 . Fin 304 - 1 may be created from upper body 202 by folding or bending a left edge of upper body 202 along a line that runs lengthwise (e.g., on a line that runs parallel to a line A in FIG. 3C ) within supporting spacer 108 .
[0022] Fin 304 - 1 may prop or buttress upper body 202 against forces that are applied to surfaces of body 306 , and may prevent upper body 202 from twisting or distorting. In addition, when supporting spacer 108 is attached to electrical outlet box 106 and a top edge of upper body 202 abuts wall 102 - 2 due to the force along arrow 110 , the top edge of fin 304 - 1 (indicated by an elliptical area 304 - 3 ) may aid in stabilizing supporting spacer 108 by providing additional contact surface. Fin 304 - 2 may be formed similarly and may serve a similar function as fin 304 - 1 . FIG. 3D shows the height of fins 304 - 1 and 304 - 2 as H F (e.g., 0.167 in.).
[0023] Center body 306 may include a piece to which other components of upper body 202 are integrally connected. In some implementations, center body 306 may include a groove or an indentation (not shown) that may be formed via punching or molding. Such a feature may provide additional rigidity and strength to upper body 202 .
[0024] Fastening tongue 206 may include a portion of upper body 202 that extends from tongue connecting portion 308 in a direction that is normal to the surface of center body 306 when supporting spacer 108 is not yet attached to electrical outlet box 106 . In some implementations, fastening tongue 206 may be further bent toward center body 306 in the direction of an arrow 320 shown in FIG. 3D , Such a configuration may aid fastening tongue 206 in gripping back panel 212 when upper body 202 is raised perpendicular to lower body 204 as shown in FIG. 2D . The length of fastening tongue 206 is illustrated in FIG. 3D as H T (e.g., 0.232 in.).
[0025] Tongue connecting portion 308 may extend from center body 306 and connect to fastening tongue 206 . In one implementation, the length of tongue connecting portion 308 (e.g., L T in FIG. 3D ) may be such that, when upper body 202 is raised with supporting in bar 108 in a position to be attached to electrical outlet box 106 (see FIG. 2D ), the surface of fastening tongue 206 may contact the bottom surface of back panel 212 without causing substantial deformation of fastening tongue 206 , tongue connecting portion 308 , or back panel 212 .
[0026] Necks 302 may include a portion that connects upper body 202 and lower body 204 . Part of necks 302 may be formed by removing slivers of material from the edges of supporting spacer 108 , thus establishing recesses 310 - 1 and 310 - 2 between upper body 202 and lower body 204 . To complete the formation of necks 302 , additional material may be cut away from between necks 302 . The length of necks 302 (e.g., W N −W O in FIG. 3C ) may be such that when a force is applied to upper body 202 to raise upper body 202 as shown in FIG. 2C , supporting spacer 108 bends at necks 302 . In some implementations, necks 302 may include a score line on either the front or the back of supporting spacer 108 . The score line is shown as the dotted portions of line C in FIG. 3C . The score line may render bending upper body 202 perpendicularly relative to back panel 212 easier than it would be without the score line.
[0027] Lower body 204 may include belly 312 , a molded portion 314 , a U-shaped hole 316 , and legs 208 and 210 . Belly 312 may include a piece to which other components of lower body 204 and necks 302 are integrally connected. Molded portion 314 may run through the surfaces of belly 312 ( FIGS. 3A and 3B ), and may provide rigidity and/or strength to lower body 204 . As shown in FIG. 3A , from the top view, molded portion 314 appears as a protuberance, and as shown in FIG. 3B , from the bottom view, molded portion 314 appears as a groove. Although the shape of molded portion 314 is illustrated as part hexagon, depending on the implementation, molded portion 314 may be implemented in other shapes.
[0028] U-shaped hole 316 may be cut in belly 312 to form tongue connecting portion 308 and fastening tongue 206 . The cut may extend from one side of tongue connecting portion 308 and traverse around tongue 206 , and end at the other side of tongue connection portion 308 . In creating the cut, the dimensions of U-shaped hole 316 may be set at L O ×W O , as shown in FIG. 3C (e.g., 0.438 in ×0.47 in). L O and W O should be large enough to accommodate the creation of fastening tongue 206 and tongue connection portion 308 , which is shown as W T wide (e.g., 0.22 in). U-shaped hole 316 and recesses 310 - 1 and 310 may reduce the strength of necks 302 , such that when a force is applied to upper body 202 of supporting spacer 108 in the direction of arrow 220 , supporting spacer 108 may bend at neck 302 as illustrated in FIGS. 2C and 2D .
[0029] Each of legs 208 and 210 may extend lengthwise relative to supporting spacer 108 , from lower body 204 's edge that is parallel to the widthwise direction of supporting spacer 108 . FIG. 3E is an expanded side view of leg 208 / 210 in FIG. 3D . As shown in FIG. 3E , leg 208 / 210 may include a thigh 322 and lower leg 324 .
[0030] Thigh 322 may be attached, on one end, to lower body 204 in a direction perpendicular to the plane of supporting spacer 108 and in the same direction as fastening tongue 206 . On the other end, thigh 322 may be attached perpendicularly to lower leg 324 . In FIG. 3E , the length of thigh 322 is shown as H H , which, in one implementation, may be set at about 0.08 in., and may correspond approximately to the thickness of back panel 212 .
[0031] Lower leg 324 may be attached substantially perpendicular to thigh 322 , in the direction away from the center of and substantially in the plane of supporting spacer 108 . In FIG. 3E , the angle between thigh 322 and lower leg 324 , shown as X, may be slightly less than 90°, such that a gap H G between the bottom surface of supporting spacer 108 and the end of lower leg 324 is less than the length of thigh 322 , H H , and, therefore, is also less than the thickness of back panel 212 . Consequently, when supporting spacer 108 is in the position illustrated in FIG. 2D , the distal end of lower leg 324 may exert a gripping force against the bottom surface of back panel 212 and aid in attaching supporting spacer 108 to electrical outlet box 106 . The magnitude of the resulting, gripping force may depend on angle X, as well as the length of lower leg 324 , shown as L G (e.g., 0.225 in) in FIG. 3E .
[0032] FIG. 4 is a flow diagram of an exemplary process 400 for attaching supporting spacer 108 to electrical outlet box 106 . Assume that electrical outlet box 106 has yet to be mounted on a wall stud. Process 400 may begin when legs 208 and 210 of supporting spacer 108 are inserted into fastening holes 214 - 2 and 214 - 3 at back panel 212 of an electrical outlet box 106 (block 402 ). To insert legs 208 and 210 into the fastening holes 214 - 2 and 214 - 3 , a user may hold supporting spacer 108 in a direction relatively and substantially normal to the surface of back panel 212 and slide legs 208 and 210 into fastening holes 214 - 2 and 214 - 3 , respectively, as shown in FIG. 2B .
[0033] Supporting spacer 108 may be placed flat against back panel 212 of electrical outlet box 106 (block 404 ). In placing supporting spacer 108 flat against back panel 212 , while legs 208 and 210 are engaged in fastening holes 214 - 2 and 214 - 3 , supporting spacer 108 may be rotated about lower body 204 's edge that touches back panel 212 , bringing fastening tongue 206 toward fastening hole 214 - 1 in back panel 212 . The rotation may stop when supporting spacer 108 is flat against the top surface of back panel 212 , and fastening tongue 206 protrudes beneath the bottom surface of back panel 212 (not shown).
[0034] Supporting spacer 108 may be bent at necks 302 , causing upper body 202 of supporting spacer 108 to be raised perpendicular to lower body 204 (block 406 ). To bend supporting spacer 108 that is placed flat against the top surface of back panel 212 , a force may be applied to lower body 204 to hold lower body 204 in place. As illustrated in FIG. 2D , when another force is applied to upper body 202 in the direction of arrow 220 (e.g., by pushing upper body 202 at the edge that extends beyond the edge of electrical outlet box 106 ), supporting spacer 108 may bend about necks 302 . The user may stop bending supporting spacer 108 when upper body 202 is perpendicular to lower body 204 .
[0035] FIG. 5 illustrates configurations of supporting spacer 108 in relation to bottom plate 212 of electrical outlet box 106 before and after supporting spacer 108 is attached to electrical outlet box 106 . As shown, upper body 202 and lower body 204 are placed flat against bottom plate 212 (see block 402 ). In this configuration, fastening tongue 206 extends from tongue connecting portion 308 into a fastening hole 214 - 1 .
[0036] When upper body 202 is raised in the direction of arrow 502 and placed in a position 504 shown in dotted lines, fastening tongue 206 and tongue connecting portion 308 may move in the direction of arrow 506 . Fastening tongue 206 and tongue connecting portion 308 may end in a position 508 shown in dotted lines.
[0037] In some implementations, because supporting spacer 108 is designed to be attached to electrical boxes with hands, edges of supporting spacer 108 may be rounded or smoothed to prevent supporting spacer 108 from accidentally cutting the hands. For example, the top corner edges of fins 304 - 1 and 304 - 2 , fastening tongue 206 , and legs 208 and 210 are illustrated in FIGS. 3A-3D as being round.
[0038] FIG. 6 illustrates a result of attaching supporting spacer 108 to electrical outlet box 106 and mounting electrical outlet box 106 to wall stud 104 - 1 ( FIG. 1 ). FIG. 6 is a side view of wall electrical assembly 100 .
[0039] As shown in FIG. 6 , wall stud 104 - 1 is located between drywall elements 102 - 1 and 102 - 2 . Further, the front edge of electrical outlet box 106 , which is mounted on wall stud 104 - 1 , is flush with the front edge of wall stud 104 - 1 . Supporting spacer 108 , which is attached to electrical outlet box 106 in accordance with process 400 and without use of any tools, is positioned and mounted between electrical outlet box 106 and drywall element 102 - 2 . Supporting spacer 108 may prevent the space between the electrical outlet box and a wall from collapsing when a force is applied to electrical utility box 106 in the direction of arrow 602 .
[0040] The foregoing description of implementations provides illustration, but is not intended to be exhaustive or to limit the implementations to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the teachings. For example, dimensions of the devices are provided for ease of understanding, but different implementations of supporting spacer 108 for different boxes may have different dimensions. Further, supporting spacer may be used not only for electrical boxes, but for other types of boxes that may be mounted on a wall.
[0041] In addition, while series of blocks have been described with regard to exemplary processes illustrated in FIG. 4 , the order of the blocks may be modified in other implementations. In addition, non-dependent blocks may represent acts that can be performed in parallel to other blocks.
[0042] No element, act, or instruction used in the present application should be construed as critical or essential to the implementations described herein unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. | An integrally formed spacer may include an upper body having a flat surface. The upper body may include a fastening tongue perpendicular to the flat surface and dimensioned to fit into a first fastening hole in a wall of an electrical box. In addition, the integrally formed spacer may include a lower body with at least one leg having a notch to receive the wall of the electrical box via a second fastening hole in the wall. Further, the integrally formed spacer may include a neck portion having two ends in a lengthwise direction of the integrally formed spacer, one end of the neck portion connected to the upper body and another end connected to the lower body. When the at least one leg is in the second fastening hole and the lower body is held flat against an outside surface of the wall of the electrical box, the fastening tongue is in the first fastening hole and bending the integrally formed spacer to set the upper body perpendicular to the lower body fastens the integrally formed spacer to the wall of the electrical box. |
This is a division of application Ser. No. 871,565, filed Jan. 23, 1978 now U.S. Pat. No. 4,210,171.
BACKGROUND OF THE INVENTION
The present invention relates to a constant-flow fluid controlling valve for automatically controlling the rate of flow of fluid passing therethrough to thereby maintain a constant rate of fluid flow even when fluctuations in fluid pressure take place at either the inlet or outlet side of the valve.
In a known constant-flow fluid controlling valves of the diaphragm or piston type, when fluid pressure on the inlet side increases or when fluid pressure on the outlet side decreases, increasing the rate of fluid flow through a restriction installed in a flow passage on the inlet side and also increasing the pressure differential across the restriction, the diaphragm or piston moves, moving a valve stem connected thereto to thereby reduce the rate of flow of fluid passing through the controlling valve. When fluid pressures are well balanced as described above, the following equation holds:
(P.sub.1 -P.sub.2)×S=F-W
where
P 1 =pressure on the upstream side of the restriction.
P 2 =pressure on the downstream side of the restriction.
S=effective area of the diaphragm.
F=pulling force of a spring exerting on the valve stem.
W=sum of all the weights of an inner valve and the parts attached thereto in fluid.
The above equation can be changed into the equation ##EQU1## Since the pressure differential created across the restriction is held constant, the controlling valve is capable of sending the fluid at a constant rate of fluid flow.
However, the difference in magnitude between the upward and downward forces acting on the inner valve must be nullified, irrespective of the values for the pressures P 1 and P 2 , in order that the above equation should be made to hold.
In other words, it is essential that a constant-flow fluid controlling valve should be designed in such a way that friction between a valve stem and the parts guiding it is reduced to a minimum and also that an inner valve is not moved up and down in a vertical line as result of pressures received directly from the fluid.
The valve of the present invention is an automatic flow controlling valve embodying such conception and thus maintaining a constant rate of fluid flow by utilizing the energy itself of the fluid flowing therethrough.
SUMMARY OF THE INVENTION
The valve according one embodiment of to the present invention is an automatic constant-flow fluid controlling valve having a valve casing, a partition wall formed therewithin to partition the valve casing into an inlet-side chamber and an outlet-side chamber, a valve port made in the horizontal part of the partition wall, a valve stem movable relative to the valve port and fitted with a valve plug adapted to open and close the valve port. A diaphragm is mounted on the top of the valve stem. An inlet-side flow passage of the valve is divided by a restriction into a pre-chamber and a post-chamber. A lower pressure-differential chamber separated from the inlet-side chamber by a valve-plug guiding member is formed between the diaphragm and the valve plug; a part of the fluid from the post-chamber of the restriction is caused to flow through a strainer into the lower pressure-differential chamber; and the fluid pressures acting on the upper and lower surfaces of the valve plug are made to be equal in magnitude and opposite to each other.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical cross-sectional view of an automatic flow controlling valve according to one embodiment of the invention.
FIG. 2 is a top view of the guide bushing 21 shown in FIG. 1.
FIG. 3 is an enlarged vertical cross-sectional view of a valve seat 24 and a lower annular or circumferential edge of the valve plug 8 shown in FIG. 1.
FIG. 4 is an enlarged vertical cross-sectional view of the narrow passage 34 shown in FIG. 1.
FIG. 5 is a vertical cross-sectional view of an automatic flow controlling valve having a modified construction, but also embodying the features of the invention.
FIG. 6 is a vertical cross-sectional view of an automatic flow controlling valve having another modified construction, but also embodying the features of the invention.
FIG. 7 is an enlarged vertical cross-sectional view of the valve stem 67 shown in FIG. 6.
FIG. 8 is a vertical cross-sectional view of an automatic flow controlling valve having a further modified construction, but also embodying the features of the invention.
FIG. 9 is a vertical cross-sectional view of an autmoatic flow controlling valve having a still further modified construction, but also embodying the featrures of the invention.
In the drawings, the same reference characters are employed to designate identical parts.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiment 1
With reference now to FIGS. 1, 2, 3, and 4 of the drawings there is illustrated a valve casing 1 which is divided by a partition wall 2 therewithin into an inlet side chamber 3 and an outlet side chamber 4. A restriction 5 is provided in the inlet side flow passage to partition it into a pre-chamber 5a and post-chamber 5b the setting of the area for fluid flow through the restriction 5 being adjusted by means of an adjusting member 33. A valve port 6 is formed in the horizontal part of the partition wall 2, the upper periphery of the valve port 6 constituting a valve seat 24 having an inwardly inclined surface as shown in FIG. 3. The valve port 6 is opened and closed by the respective separation and contacting of the tapered edge 32 of a cylindrical valve plug 8 from and with the valve seat 24. A hollow valve stem 7 extends through the valve port 6 in the direction of the vertical axis of the valve casing 1. The cylindrical valve plug 8 serving to open and close the valve port 6 is fixedly mounted on the valve stem 7 by means of a transverse support plate 25. The transverse support plate 25 is dimensioned in such a way that the axial fluid-pressure receiving areas of its upper and lower surfaces are equal to each other. The cylindrical valve plug 8 also is dimensioned in such a way that the axial fluid-pressure receiving areas of the upper and lower annular edges of a cylindrical member 26 are equal to each other. A diaphragm 9 partitions a pressure-differential chamber into an upper pressure-differential chamber 12 and a lower pressure-differential chamber 13 and is secured to the upper end of the valve stem 7 by means of retainers 10 and 11, the upper and lower pressure-differential chambers 12 and 13 respectively receiving back pressure and positive pressure. The valve stem 7 is fitted at its lower end with a strainer 15 having filtering medium 14. The strainer 15 is housed in an easily attachable and detachable strainer case 16, the strainer case 16 being joined by threading to the valve casing 1 at its bottom circular end. It is preferred to employ a transparent strainer case because the inside can then be seen through the strainer case from the outside. A valve-plug guiding member 17 fitted at its lower part with a sliding-contact ring 18 is joined by threading on the upper inner peripheral surface of the valve casing 1, thus separating the lower pressure-differential chamber 13 from the outlet-side chamber 4. The inner peripheral surface of the valve plug 8 is slidable on the sliding-contact ring 18. Since the pressure P 2 of the fluid flowing from the strainer 15 through the hollow valve stem 7 and a plurality of communicating holes 23 into the valve-plug guiding member 17 and the lower pressure-differential chamber 13 is greater than the fluid pressure P 3 within the outlet-side chamber 4, the fluid leaks along a sliding-contact surface X and through a clearance space between the valve-plug guiding member 17 and the valve plug 8 into the outlet side chamber 4. During this time, because the fluid entering the valve-plug guiding member 17 and the lower pressure-differential chamber 13 has been filtered through the strainer 15 before flowing into the hollow valve stem, there is no possibility of hindering the valve plug 8 from moving up and down smoothly due to the introduction of impurities into the sliding contact surface X. The pre-chamber 5a of the restriction 5 and the upper pressure-differential chamber 12 communicate with each other through a branch flow-passage 19. A spring case 27 positioned coaxially over the valve stem 7 forms with the diaphragm 9 the upper pressure-differential chamber 12. A spring 20 is mounted coaxially within the spring case 27 between the upper end thereof and the top of the valve stem 7. A guide bushing 21 serves to guide the lower part of the valve stem 7. As shown in FIG. 2, a plurality of concave recesses 22 are formed in the inner periphery of the guide bushing 21 so that the area of the sliding-contact surface between the bushing and the valve stem 7 may be reduced. The guide bushing 21 is so constructed to reduce frictional resistance with the valve stem 7 and also to prevent the introduction of impurities therebetween. The numerals 30 and 31 respectively designate inlet and discharge pipes and the numerals 28 and 29 respectively designate for flanges attachment to the inlet pipe 30 and the discharge pipe 31. The, the action of the controlling valve of this embodiment will now be described. The major portion of the fluid A which has reached the inlet 3 flows sequentially through pre-chamber 5a, restriction 5, post-chamber 5b, inlet side chamber 3, and the valve port 6 into the outlet side chamber 4 and is discharged through the outlet 4. Concurrently, a part of the fluid which has entered pre-chamber 5a flows through the branch flow-passage 19 into the upper pressure-differential chamber 12 and a part of the fluid which has entered the pre-chamber 5b flows through the strainer 15, the valve stem 7, and the communicating holes 23 into the lower pressure-differential chamber 13. If the fluid pressures within the pre- and post-chambers 5a and 5b respectively are represented by P 1 and P 2 , then the back pressure within the upper pressure-differential chamber 12 becomes equal to the fluid pressure P 1 because the upper pressure-differential chamber 12 communicates with the prechamber 5a. The fluid pressure within the lower pressure-differential chamber 13 has the pressure P 2 because the fluid pressure inside the lower pressure-differential chamber 13 is the same as that inside the post-chamber 5b. Therefore, when fluctuations in pressure differential take place across the restriction 5, pressure differentials of equal value are generated between the upper and lower pressure-differential chambers 12 and 13. The diaphragm 9 operates, to move the valve stem 7 upwardly or downwardly to automatically regulate the rate of fluid flow through the valve in accordance with such fluctuations in pressure differential. During this time the upper and lower surfaces of the transverse support plate 25 has applied thereto the same fluid pressure as P 2 inside the lower pressure-differential chamber 13 and the same fluid pressure P 2 inside the post-chamber 5b, the fluid pressures applied on the upper and lower surfaces of the transverse support plate 25 thus compensating each other and thereby cancelling out. If the fluid pressure inside the outlet side chamber 4 is represented by P 3 , fluid pressure P 3 is exerted axially to each of the circumferential upper and lower edges of the cylindrical member 26 of the valve plug 8, these fluid pressures of P 3 secure to compensate each other and cancel out. Consequently the valve plug 8 is not at all influenced by fluctuations in flow rate and fluid pressure, and only the up and down movement of the diaphragm 9 caused by fluctuations in the pressure differential of (P 1 -P 2 ) is transmitted by means of the valve stem 7 to the valve plug 8, thereby permitting it to adjust the degree of opening of the valve to automatically regulate the rate of fluid flow therethrough.
As described above, in the controlling valve of this embodiment, the rate of the fluid flow can be held nearly constant by adjusting the degree of opening of the restriction 5 to a desired point by means of an adjusting member 33 provided with a scale. The fluid pressures acting on the valve plug 8 compensate one another and cancel out owing to the operation of the diaphragm 9 caused by the action of the positive and back pressures thereon as described above which permits an accurate supply of fluids at a constant rate of flow. Further the adverse effect of impurities in the fluids is prevented by removing the impurities through the strainer 15 at the sacrifice of a small reduction in the degree of accuracy caused by the change in effective area depending on the up and down movement of the diaphragm 9. There is no possibility of introducing impurities between the inner peripheral surface of the valve plug 8 and the sliding-contact surface of the slide guide-ring 18 positioned on the peripheral surface of the valve-plug guiding member 17, the fluid entering the lower pressure-differential chamber 13 having been filtered through the strainer 15 before being permitted to flow into the inner valve. The dust and dregs having been removed, the valve plug 8 can move up and down smoothly and surely in a vertical line, to effectively close the valve port 6 and to be trouble free. Furthermore, because the strainer 15 is covered with the easily attachable and detachable strainer case 16, cleaning and exchanging it can be easily carried out. The materials for the slide guide-ring 18 and the guide bushing 21 are selected from those that can reduce the coefficient of friction between the sliding-contact surfaces thereby enabling the degree of accuracy of the valve stem 7 and the valve plug 8 which move up and down to increase.
Since the upper periphery of the valve port 6, constituting the valve seat 24, is tapered on its inner surface as shown in FIG. 3, stream lines are uninterrupted by virtue of the taper throughout the cross-sectional area of the intermediate flow passage formed between the valve seat 24 and a lower tapered edge 32 of the cylindrical member 26, independently of the speed of the fluid or whether the lower annular or circumferential edge of the cylindrical member 26 is square or is tapered as shown in FIG. 3. Therefore the balance between axial fluid pressures acting on the valve plug 8 can be always maintained accurately, the operation of the valve plug 8 caused by the action of the diaphragm 9 can be effectively performed, and positive closing of the valve port 6 can be expected when the lower tapered edge 32 of the cylindrical member 26 comes into close contact with the tapered valve seat 24, thereby providing a controlling valve of a high degree of accuracy.
In this embodiment, when a part of the branch flow-passage 19 leading to the upper-differential chamber 12 is formed into a narrow fluid passage 34 as shown in FIG. 4, then the problem of a hunting phenomenon of diaphragm 9 caused by fluctuations in fluid pressure can be avoided.
That is to say, since the rate of flow of a fluid flowing into and from the upper pressure-differential chamber 12 is reduced by interposing the narrow flow passage 34 between the branch flow-passage 19 and the upper pressure-differential chamber 12, for example, even when a sharp increase in fluid pressure occurs in the pre-chamber 5a and is transmitted through the branch flow-passage 19 to the upper pressure-differential chamber 12, the fluid does not flow rapidly at a high flow-rate according to the increased fluid pressure into the upper pressure-differential chamber 12, but instead flows thereinto at a low flow-rate. The resultant gentle application of fluid pressure on the diaphragm 9 causes it to operate slowly or to move downwardly and slowly. Hence, even if fluctuations in fluid pressure occur on the inlet side 3 and are transmitted to the upper pressure-differential chamber 12, the gentle operation of the diaphragm 9 eliminates the possibility of hunting moving the valve plug 8 upwardly and downwardly with stability and certainty to automatically regulate the rate of fluid flow through the valve very effectively.
Embodiment 2
The fluid flow controlling valve of this embodiment has a modified construction and includes a cylindrical valve plug serving to open and close a valve port positioned as to move up and down in a vertical line freely; no difference in magnitude existing between the axial opposite forces acting on the valve plug irrespective of fluctuations in the flow rate and pressure of the fluid.
Referring to FIG. 5 there is described a valve casing 1 made into a flat bottomed valve casing by omitting strainer 15 and strainer case 16 shown in FIG. 1. A valve port 6 is made in the horizontal part of a partition wall 2 provided within the valve casing 1. Over the valve port 6 there is positioned a cylindrical valve plug 35 for opening and closing the valve port 6. The valve plug 35 is secured by means of a horizontal spider 36 to a vertical valve stem 37, the vertical valve stem 37 having its axis common to the valve casing 1 and the valve port 6. Filtering medium 40 such as wire gauze is placed between each of the legs of the horizontal spider 36. The valve plug 35 is dimensioned in such a way that the areas of the fluid pressure-receiving surfaces of the upper and lower edges of its peripheral wall are equal to each other. A diaphragm 9 is provided within a pressure-differential chamber and is mounted on the top of the valve stem 37 by means of metallic retainers 10 and 11, partitioning the pressure-differential chamber into an upper pressure-differential chamber 12 and a lower pressure-differential chamber 13. A cylindrical, valve-plug guiding member 38 is joined by threading to the upper inner peripheral surface of the valve casing 1, separating the lower pressure-differential chamber 13 from an outlet-side chamber 4 and also having on its lower outer peripheral surface a slide guide-ring 39 facilitating the sliding of the inner peripheral surface of the valve plug 35 to freely thereon.
The action of the controlling valve of this embodiment will now be described. The major portion of the fluid which has reached inlet 3 flows through a pre-chamber 5a of a restriction 5, and as described in connection with FIG. 1, a post-chamber 5b. The fluid then flows through, an inlet side chamber 3, valve port 6, and an intermediate flow passage between the valve plug 35 and a valve seat 24 into an outlet side chamber for discharge 4. At this time, in the same manner as that of the preceding embodiment, some part of the fluid is introduced through a branch flow-passage 19 into the upper pressure-differential chamber 12. Part of the fluid is filtered through the filtering medium 40 positioned within the valve plug 35 and flows through an annular clearance 41 between the valve stem 37 and an internal flange of the valve-plug guiding member 38, and through an annular opening 42 between the metallic retainer 11 and the valve-plug guiding member 38 into the lower pressure-differential chamber 13. Hence the up and down movement of the diaphragm 9 is transmitted through the valve stem 37 to the valve plug 35 to regulate the rate of fluid flow through the valve in the same manner as described in connection with FIG. 1 in accordance with changes in the pressure differential P 1 -P 2 .
Embodiment 3
The construction of the fluid flow controlling valve of this embodiment is such that a variable-area orifice that adjusts the area of a flow passage for fluids passing therethrough is formed in place of the restriction 5 of the first and second embodiments on the inlet side of the valve. A branch flow passage leading to an upper pressure-differential chamber is provided on the upstream side of the orifice and a bypass leading to a lower pressure-differential chamber and a valve port are provided on the downstream side of the orifice. The variable orifice is set for the desired flow-rate before the rate of fluid flow is regulated by means of a valve plug having a diaphragm to be held constant.
Referring to FIGS. 6 and 7 there is shown a box-type valve casing 51 having on its inlet side an inlet conduit 52. The inlet conduit 52 has therewithin a flow passage 53 of larger diameter and a flow passage 54 of smaller diameter. The flow passage 53 and the flow passage 54 communicate with each other through a smaller-diameter hole or orifice 55. The lower tapered end 80 of an orifice adjusting stem 56 is cooperable with the hole 55. The orifice adjusting stem 56 is so positioned loosely through a larger-diameter hole 57 made in the side wall of the inlet conduit 52 as to slide therewithin. The upper threaded part of the stem 56 is engaged with threads on the inner peripheral surface of a guide bushing 58 fixedly positioned above the larger-diameter hole 57. An orifice adjusting mechanism is constructed in such a way that the lower tapered end 80 of the orifice adjusting stem 56 is made to contact with and separate from the smaller-diameter hole 55 by turning a handwheel 59 surmounting and integral with the stem 56 to adjust the cross-sectional flow area for through the orifice 55. The handwheel 59 has proximate thereto a dial and whereby the setting of the rate of flow can be adequately adjusted. The hole orifice 55 communicates through the flow passage 54 with a flow passage 60 formed in the lower thicker portion of the valve casing 51 and communicates further through a valve port 62 with an outlet-side flow passage 61. A pressure-differential chamber is formed within the upper part of valve casing 51 and is partitioned by a diaphragm 64 into an upper pressure-differential chamber 63 and a lower pressure-differential chamber 81. The upper pressure-differential chamber 63 communicates through a flow passage 65 with the flow passage 53 of larger diameter, namely the upstream side of the restriction orifice 55. The lower pressure-differential chamber 81 communicates through a flow passage 66 leading to the flow passage 60 with the flow passage 54 of smaller diameter, namely the downstream side of the restriction 55. The diaphragm 64 is secured to about the middle of a valve stem 67 by means of a metallic retainer 68, the lower part of the valve stem 67 being so inserted closely within a guide hole 70 formed in a valve guide 69 as to slide freely therewithin. The annular space between the outer circumferential surface of the flange of the valve guide 69 and the inner circumferential surface of the lower pressure-differential chamber 81 is filled with filtering medium 82 such as wire gauze, thus constituting a strainer. The upper part of the valve stem 67 is positioned coaxially within a spring case 71 surmounting the valve casing 51, and a spring retainer 72 is attached to the upper end of the valve stem 67. A coil spring 74 is so interposed compressively between the lower surface of the spring retainer 72 and the upper surface of a ceiling plate 73 of the valve casing 51 as to bias the valve stem 67 upwardly. The valve stem 67 is positioned loosely through a central hole 75 formed in the plate 73, the central hole 75 allowing the spring case 71 and the upper pressure-differential chamber 63 to communicate with each other. The lower part of the valve stem 67 constitutes a valve plug 76. The lower end of the valve plug 76 is opposed to a valve seat 83 formed in the upper periphery of the valve port 62, the valve port 62 being formed between the flow passage 60 and the outlet-side flow passage 61. The detailed structure of the valve plug 76 is shown in FIG. 7. The valve plug is formed into a cylindrical tube 78, the cylindrical tube 78 being closed at its upper end and opened at its lower end. The upper end of the cylindrical tube 78 constitutes a shoulder 79 and the lower end of the cylindrical tube 78 is shaped into an inclined surface 77. Further the cylindrical tube 78 is dimensioned to have its inner diameter D 2 made to be equal to the outer diameter D 1 of the valve stem 67.
The action of the controlling valve of this embodiment will now be described. When the area for fluid flow through the restriction 55 is adequately set by turning the handwheel 59 and a fluid W is allowed to enter the inlet conduit 52, then major portion of the fluid W flows through the restriction 55, the flow passages 54 and 60, and the valve port 62 into the outlet-side flow passage 61 and leaves through an outlet. The remainder of the fluid W flows through passages 65 and 66 into the upper and lower pressure-differential chambers 63 and 81 respectively. If fluid pressures on the upstream and downstream sides of the restriction 55 respectively are taken to be P 1 and P 2 , then fluid pressures acting on the upper and lower surfaces of the diaphragm 64 respectively become P 1 and P 2 . If pressure on the downstream side of the valve port 62 is taken to be P 3 , then the pressures P 2 , P 3 , and P 3 respectively are applied on the ceiling surface, shoulder 79 and inclined circumferential surface 77 of the cylindrical tube 78 of the valve plug 76. When the rate of fluid flow through the inlet conduit 52 is increased or decreased, thereby increasing or decreasing the pressure P 1 , the diaphragm 64 thus moves upwardly or downwardly, bringing the valve plug 76 close to or moving it away from the valve port 62 and also decreasing or increasing the cross-sectional area of the intermediate flow passage formed between the valve port 62 and the lower annular or circumferential edge of the cylindrical tube 78 of the valve plug 76 so that fluids passing through the valve will have a constant rate of fluid flow. When pressures are well balanced as described above, the following equation holds:
(P.sub.1 -P.sub.2)×S=F-W
where
P 1 =pressure on the upstream side of the restriction 55.
P 2 =pressure on the downstream side of the restriction 55.
S=effective area of the diaphragm 64.
F=pulling force of the coil spring 74 exerted on the valve stem 67.
W=sum of all the weights of the inner valve and the parts attached thereto in the fluid W.
The above equation can be changed into the equation ##EQU2##
The rate Q of fluid flow through the restriction 55 can be expressed by the equation ##EQU3## where H= 1 -P 2 =a constant value.
g=acceleration of gravity.
K=coefficient of exit.
a=cross-sectional fluid flow area through orifice or restriction 55.
This equation consequently gives
Q∝a.
Hence the rate Q of fluid flow is held constant unless the area for fluid flow through the restriction 55 is altered. Because a pressure as high as the fluid pressure P 3 is applied on the lower inclined peripheral surface 77 of the cylindrical tube 78 of the valve plug 76, pressures exerted on the upper and lower edges 79 and 77 of the cylindrical tube become nearly equal to each other. The valve plug 76 thus is not affected very much by fluctuations in pressure differential (P 2 -P 3 ) created across the valve port 62, but is accurately driven substantially only by the displacement movement of the diaphragm 64 caused by fluctuations in pressure differential created across the restriction 55, which thereby permits the rate of fluid flow through the valve to be held constant.
Embodiment 4
The construction of the fluid flow controlling valve of this embodiment is such that a box-shaped partition wall defining on its one side an inlet is provided within a valve casing, partitioning it into an inlet-side chamber and an outlet-side chamber; a round hole and a valve port respectively are made in the upper and lower horizontal parts of the partition wall; a valve stem is positioned through the round hole and the valve port, the valve stem being fitted at its upper end with a diaphragm, having a valve plug to open and close the valve port and a pressure-receiving slide member slidable on the inner peripheral surface of a guide bushing inserted into the round hole. The valve stem is movable with the up and down movement of the diaphragm; the fluid passing through a radial clearance between the inner peripheral surface of the guide bushing and the outer peripheral surface of the pressure-receiving slide member after having been purified through a strainer before flowing into the radial clearance.
In the fluid flow controlling valve of this embodiment, because the fluid passing through the radial clearance between the outer peripheral surface of the pressure-receiving slide member and the inner peripheral surface of the guide bushing has been purified through the strainer before flowing into the radial clearance, the slide member can slide smoothly on the inner surface of the guide bushing, resulting in accurate automatic control.
Referring to FIG. 8 there is shown a valve casing 91 provided therewithin with a box-shaped partition wall 92. The partition wall 92 is opened at its one side and partitions the valve casing 91 into an inlet-side chamber 93 and an outlet-side chamber 94. A restriction 96 that provides an adjustment of fluid flow rate therethrough is positioned in a flow passage between the outlet-side chamber 94 and an outlet 95. This setting can be adjusted by the use of an externally located dial (not shown in the drawing). A round hole 97 and a valve port 98 respectively are made in the upper and lower horizontal parts of the partition wall 92. A guide bushing 99 is screwed into the round hole 97. The guide bushing 99 is provided with an integral strainer 100. The strainer 100 has on its entire peripheral side a filtering medium 101 such as wire gauze and projects from the upper horizontal part of the partition wall 92 into the inlet-side chamber 93 and communicates therewith. A hole 112 is made in the bottom 111 of the strainer 100 and a valve stem 102 described later is positioned slidably therethrough. By making the diameter of the hole 112 adequately larger than the outer diameter of the valve stem 102, a sufficient radial clearance is allowed to exist between the hole 112 and the peripheral surface of the valve stem 102 so as to prevent the close contact thereof with the hole 112 as well as the clogging of the radial clearance by impurities, which might otherwise interfere with the up and down movement of the valve stem 102. Since the fluid which has entered the strainer 100 is allowed to flow in the directions of the arrow heads, there is no possibility of the fluid entering the strainer 100 through the radial clearance between the hole 112 and the peripheral surface of the valve stem 102; that is to say, the whole of the fluid entering the inside of the strainer 100 has been purified through the filtering medium 101 before flowing into the inside of the strainer 100.
The valve stem 102 extends slidably through the valve port 98 and through the hole 122 made in the strainer 100 and is provided with a pressure-receiving slide member 103 slidable on the inner peripheral surface of the guide bushing 99 and with a cylindrical inner valve 104 which is adapted to open and close the valve port 98. The upper half of the inner valve 104 constitutes a cylindrical valve plug 113 and is cooperable with a valve seat 118 of the valve port 98. The lower half of the inner valve 104 has a slightly smaller diameter than the outer diameter of the valve plug 113 and constitutes a mounting member 114 for attachment thereof to the valve stem 102. The peripheral surface of the mounting member 114 is slidable on the inner peripheral surface of a tube member 115 inserted into a round hole made in a bottom plate 116 of the valve casing 91. The mounting member 114 of the inner valve 104 and the pressure-receiving slide member 103 are dimensioned in such a way that all of the pressure-receiving areas of their respective upper and lower surfaces are equal to one another. A diaphragm 106 is secured to the upper end of the valve stem 102 by means of metallic retainer 105, thereby defining an upper pressure-differential chamber 107 and a lower pressure-differential chamber 108. The lower pressure-differential chamber 108 communicates with the outlet-side chamber 94. The upper extremity of a spring 109 housed within a spring case 117 is connected to the lower extremity of the valve stem 102, the valve stem 102 being biased downwardly by the spring 109. A branch flow-passage 110 is provided between the restriction 96 and outlet 95 to the upper pressure-differential chamber 107. The outlet-side chamber 94 and the spring case 117 communicate with each other through a branch flow-passage 120.
The action of the fluid flow controlling valve of this embodiment will now be described. The fluid which has reached the inlet flows through the inlet-side chamber 93 and valve port 98 into the outlet-side chamber 94 and leaves through the restriction 96 and through the outlet 95. A part of the fluid which has reached the outlet 95 is introduced through the branch flow-passage 110 into the upper pressure-differential chamber 107. When the rate of fluid flow increases on the inlet side and thereby the fluid pressure inside the outlet-side chamber 94 immediately upstream of the restriction 96 become higher than that at the outlet 95, moving the diaphragm 106, the valve stem 102, and the cylindrical inner valve 104 upwardly, the cross-sectional area of an intermediate fluids flow passage formed between the valve port 98 and the upper annular or circumferential edge of the cylindrical valve plug 113 is decreased so as to limit the rate of fluid flow through the valve. When the rate of fluid flow is limited in this manner and the pressure-differential between the upper and lower pressure-differential chambers 107 and 108 approaches zero, the diaphragm 106 resumes its position to automatically regulate the rate of fluid flow through the valve. If the pressures inside the inlet- and outlet-side chambers 93 and 94 respectively are represented by P 1 and P 2 , then the pressure P 1 is applied on the upper surface of the mounting member 114 and also on the lower surface of the pressure-receiving slide member 103, and the pressure P 2 is applied on the lower surface of the mounting member 114 and also on the upper surface of the pressure-receiving slide member 103. Because the pressure-receiving areas of the upper surface of the mounting member 114 and the lower surface of the pressure-receiving slide member 103 are equal to each other, the pressures acting on them are equal in magnitude and opposite to each other, compensating and cancelling out each other. Similarly the pressures acting on the lower surface of the mounting member 114 and on the upper surface of the pressure-receiving slide member 103 are equal in magnitude and opposite to each other, compensating and cancelling out each other. Further, the pressure P 2 acts on the upper and lower circumferential edges of the cylindrical valve plug 113, compensating and cancelling out each other. Therefore all of the pressures which the cylindrical inner valve 104 and the pressure-receiving slide member 103 receive compensate and thereby cancel out one another. The cylindrical inner valve 104 thus is not influenced at all by fluctuations in flow rate and fluid pressure, and only the up and down movement of the diaphragm 106 is transmitted thereto by means of the valve stem 102. A single inner valve, namely the cylindrical inner valve 104 thus automatically regulates the rate of fluid flow through the valve effectively. Although pressure P 1 inside the inlet-side chamber 93 is higher than P 2 inside the outlet-side chamber and thereby 94 gives rise to the leakage of fluids from the higher-pressure side to the lower pressure-side through radial clearance 119 between the inner peripheral surface of the guide bushing 99 and the outer peripheral surface of the pressure-receiving slide member 103 in the directions of arrow heads, the purification of fluids through the filtering medium 101 results in no possibility of dust and dregs being introduced into the radial clearance 119, which permits the valve stem 102 to move smoothly up and down.
As described above, the fluid flow controlling valve of this embodiment is able to always supply fluids at a constant rate of flow and as results in accurate, effective, and trouble-free operation, the fluid entering the radial clearance 119 is purified through the strainer 100 before flowing into the guide bushing 99, which prevents the introduction of impurities into the radial clearance 119, reduces the friction between the pressure-receiving slide member 103 and the guide bushing 99, and thus permits the valve stem 102 to move smoothly up and down.
Embodiment 5
Referring to FIG. 9 there is shown a valve casing 121 partitioned with a partition wall 122 therewithin into an inlet-side flow passage 123 and an outlet-side flow passage 124. A valve seat 126 is provided in the horizontal part of the partition wall 122. An umbrella-shaped restriction adjusting member 127 for adjusting the cross-sectional flow area of a restriction 125 cooperates with the valve seat 126 and when spaced therefrom forms therewith the restriction 125, constituting a first intermediate flow passage for fluids passing through the valve. Section 128 of the adjusting member 127 is joined by threading to the valve casing 121 in the bottom thereof. Handle 130 is integral with a shank 129 of the adjusting member 127. Turning of the handle causes the adjusting member 127 to move up and down relative to valve port 131 formed with the valve seat 126 so that the setting of the rate of fluid flow through the valve can be adjusted as desired. A chamber on the other side of the partition wall 122 constitutes a post-chamber 150 of the restriction 125. The lower annular or circumferential edge 151 of a valve plug 132 is cooperable with valve seat 126 provided in the horizontal part of the partition wall 122 and forms with the valve seat 126 a second intermediate flow passage for fluids passing through the valve. The valve plug 132 has a cylindrical form and is closed at its upper extremity by means of a top plate 133. The top plate 133 of the valve plug 132, a bellows-diaphragm 134, and a retainer plate 135 are secured together to the lower end of a valve stem 136 with the bellows-diaphragm 134 sandwiched between the retainer plate 135 and the top plate 133. The upper half of the valve plug 132 is positioned coaxially within a lower pressure-differential chamber 139 and is made to contact loosely with the inner surface of a liner 140 through the medium of the bellows-diaphragm 134. The peripheral part 141 of the bellows-diaphragm 134 is sandwiched between the upper peripheral part of the lower pressure-differential chamber 139 and the lower surface of a flange 142 of a spring case 143. The bellows-diaphragm 134 serves to separate the lower pressure-differential chamber 139 from an upper pressure-differential chamber 144 within the spring case 143. The inlet-side flow-passage 123 and the upper pressure-differential chamber 144 communicate with each other through a branch flow-passage 138 and a flow passage 145 in the flange 142. The valve stem 136 is positioned coaxially within the spring case 143 which is sealed with a bonnet 148 and is biased upwardly by a spring 146, the upper end of the spring 146 being secured to the valve stem 136 a short distance below the upper end thereof.
The action of the fluid flow controlling valve of this embodiment will now be described. The major portion of the fluid which has reached an inlet flows through the inlet-side flow passage 123, the pre-chamber 149 of the restriction 125, the restriction 125 the valve port 131 and through the second intermediate flow passage into the post-chamber 150 of the restriction 125 and leaves through the outlet-side flow passage 125 and through an outlet a part of the fluid in the inlet-side flow passage 123 is introduced through the branch flow-passage 138 and through the flow passage 145 formed in the flange 142 into the upper pressure-differential chamber 144. If fluid pressures in the inlet-side flow passage 123 and the post-chamber 150 of the restriction 125 respectively are taken to be P 1 and P 2 , then the fluid pressures P 1 and P 2 respectively act within the upper pressure-differential chamber 144 and the lower pressure-differential chamber 139. Therefore, when fluctuations in pressure differential take place across the restriction 125, that is, the first intermediate flow passage 125, creating between the upper and lower pressure-differential chambers 144 and 139 pressure differentials equalling the values of the varying pressure differentials across the restriction 125, the bellows-diaphragm 134 thus operates, moving the valve stem 136 and the valve plug 132 upwardly and downwardly to automatically regulate the rate of flow of fluids passing through the valve port 131. At this time, If fluid pressure in the outlet-side flow passage 124 is taken to be P 3 , the fluid pressure P 3 is applied on the inner surface and outer exposed surface of the valve plug 132 and also to the lower annular or circumferential edge 151 thereof. However, since the pressures acting on such parts compensate each other and thereby cancel out, the valve plug 132 is not affected by fluctuations in the rate of fluid flow and in fluid pressure only the up and down movement of the bellows-diaphragm 134 is transmitted through the valve stem 136 to the valve plug 132.
As described above, in the fluid flow controlling valve of this embodiment, the setting of the cross-sectional flow area of the restriction 125, that is, the first intermediate flow passage through the valve is adjusted to a desired value by means of the restriction adjusting member 127. The upward and downward motion of the valve plug 132 fitted with the bellows-diaphragm 134 is automatically caused by fluctuations in pressure differential across the restriction 125 to thereby maintain the rate of fluid flow through the valve at a prescribed value. The controlling valve of this embodiment has the advantages in that it is simple in mechanism and structure, high in the degree of accuracy of control, almost free from damage, easy to handle and also to assemble and disassemble. | An automatic fluid control valve for maintaining a substantially constant fluid flow rate includes a partition wall within a valve casing between a fluid inlet and a fluid outlet. A restriction adjusting member is mounted movably in the valve casing and includes a tapered end movable relative to a valve port in the partition wall to define a restricted passageway for fluids with the adjacent walls of the valve port. A valve stem is movable within the casing and has a valve thereon cooperable with the valve port to regulate the flow of fluids therethrough in response to changes in fluid pressure differential. A diaphragm is operatively connected to the valve stem and separates a region within the valve casing into a pair of pressure-differential chambers, and a flow passage is formed in the casing communicating one pressure-differential chamber with the inlet chamber, the other pressure-differential chamber communicating with the downstream side of the valve port. |
PRIOR APPLICATION
This application is a continuation-in-part of our prior copending U.S. application Ser. No. 003,544, filed Jan. 15, 1979.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is in the field of cargo handling equipment, and more specifically relates to a buckle for use with a belt and which operates on an overcenter principle and which has an extremely simple and rugged structure.
2. The Prior Art
The overcenter principle as applied to buckles is now new. All of the known prior art overcenter buckles employ parts which move with respect to one another. Typically, such buckles had a three-dimensional structure in which flanges extended from a handle, and in which certain moving parts were mounted between the flanges.
Although the prior art overcenter buckles may have been strong enough to operate properly in their intended use, in practice their life was limited by their inability to withstand accidental mistreatment.
Typically, such buckles are used to secure belts which tie down cargo, and in this setting, cargo-moving vehicles such as forklifts not uncommonly run over the buckles, destroying them.
SUMMARY OF THE INVENTION
The present invention is a buckle which operates on an overcenter principle but which, compared to prior art buckles, is more capable of withstanding mistreatment.
In one embodiment, the buckle of the present invention is a single piece, while in other embodiments, it consists of more than one piece rigidly connected to form a solid structure.
In the preferred embodiment, the buckle is formed of flat plate stock, and has a generally flat structure. Hence, it has great resistant to damage caused by being run over by vehicles.
Because the overcenter buckle of the present invention is formed of flat plate stock, it can be stamped out of such stock and therefore is relatively inexpensive to manufacture.
In accordance with a preferred embodiment of the present invention, the buckle is aligned in its open position and the belt is threaded through it and pulled tight. Next, the handle of the buckle is swung to the locked position, winding the belt over one end of the buckle and thereby tensioning the belt. The handle is then removably attached to the tensioned belt to prevent accidental unlocking.
The novel features which are believed to be characteristic of the invention, both as to organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which several preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a preferred embodiment of the buckle in its open position;
FIG. 2 is a cross-sectional view taken in the direction 2--2 of FIG. 1 showing a preferred embodiment of the buckle in its open position;
FIG. 3 is a side cross-sectional view of a preferred embodiment of the buckle in its locked position;
FIG. 4 is a plan view in the direction 4--4 of FIG. 3 showing a preferred embodiment of the present invention in its locked position;
FIG. 5 is a perspective view of an alternative embodiment of the present invention in its open position;
FIG. 6 is a cross-sectional view of the alternative embodiment shown in FIG. 5 in a direction 5--5, showing the alternative embodiment in its locked position;
FIG. 7 is a perspective view of a further embodiment of the invention in its open position;
FIG. 8 is a sectional view taken along the line 8--8 of FIG. 7;
FIG. 9 is a sectional view, similar to FIG. 8, showing the buckle in its locked position, and
FIG. 10 is a sectional view taken along the line 10--10 of FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings, in which like parts are denoted by the same reference numeral throughout, there is shown in FIGS. 1 and 2 a preferred embodiment of the overcenter buckle of the present invention in its open position. The essential parts of the buckle 10 are the handle 15 and the cross members 30, 32. Both the handle 15 and the cross members 30, 32 are formed of flat plate stock, and the handle includes a front surface 11 and a rear surface 13. The cross members 30, 32 are attached to the front surface 11 by the rivets 34.
The buckle 10 is normally permanently connected by a rope 20 to a clasp 22 leading off in a first direction. The rope 20 passes from the rear surface 13 forward through the eyes 26, and is retained from pulling through the eyes by knots 27 tied at the ends of the loop or rope 20.
Typically, the buckle is used to secure a belt or strap 12 to the rope 20 for the purpose of restraining the movement of cargo on a vehicle. The strap or belt 12 includes a free end 14 as well as a standing part 16. The standing part 16 extends in the opposite direction from the rope 20 and terminates in a clasp 18. The clasps 18, 22 are normally engaged to fittings on the vehicle, and the belt 12 normally partially encircles the cargo. In use, the free end 14 of the belt 12 is threaded through the buckle 10 as shown in FIG. 2, with the buckle 10 in its open position. It is seen that a bight is formed in the belt 12 which encircles the retaining cross member 32 and that the free end 14 of the belt is jammed between the standing part 16 and the first cross member 30. Thereafter, the handle 15 is pulled in the direction of the arrow in FIG. 2 relative to the rope 20 and rotated through an angle of approximately 180 degrees, so that the buckle 10 assumes the locked or closed position shown in FIGS. 3 and 4. In moving the handle 15 in the direction of the arrow, the upper part of the handle passes through a loop, as indicated, that may be formed in the rope 20. Also, of course, the loop may pass in front of the handle 15, i.e., to the right of the handle as shown in FIG. 2 or behind the handle as shown in FIG. 1, if the loop is smaller than the upper part of the handle such that the upper part of the handle could not pass through the loop.
As the handle 15 is rotated to the locked position in the direction of the arrow in FIG. 2, slack in the belt 12 is taken up as the belt is wound around the first cross member 30, as the latter moves from a position below the knot 27 as shown in FIG. 2 to the locked position in which the first cross member 30 is above the knot 27, as shown in FIGS. 3 and 4. The rotation of the handle 15 takes place about the line 25 which is defined by the centers of the eyes 26. The tensioning of the belt 12 which occurs as the handle 15 is rotated places the belt 12 and the rope 20 under tension. This tension is found to produce a torque on the handle 15, tending to rotate it in the direction shown by the arrow F in FIG. 3, i.e., forcing the end 23 of the handle against the belt 12. The force increases with increasing tension in the belt 12, preventing the buckle from being pulled open. A safety catch 29 is provided to insure that the buckle will stay closed even if the cargo shifts in such as manner as to relieve temporarily the tension in the belt 12. The locking action of the buckle is believed to result from the fact that the rear surface 31 of the first cross member 30 is located in front of the rear surface 13 of the handle 15 as shown in FIG. 3. In the best mode of constructing the buckle, the offset between the rear surface of the first cross member 31 and the rear surfaces 13 of the handle 15 is relatively small to prevent the locking force on the end of the handle 23 from becoming so large that the buckle cannot be rotated again to its open position. Typically, the force on the end of the handle should not excees 20 pounds, while the tension in the belt 12 may be on the order of several thousand pounds.
In the preferred embodiment of FIGS. 1-4, it is desirable that the eyes 26 extend laterally from the opposite sides 24 of the handle 15, so that as the buckle is rotated, the rope 20 can pass readily around the outside 19 of the eyes 26.
Another feature common to all embodiments of the buckle is that the location of the retaining cross member 32 is immaterial. For example, in the embodiment of FIGS. 1-4, the structural brace 33 interconnecting the handle sides 24 could have served as the retaining cross member. The embodiment of FIGS. 1-4 is particularly sturdy and able to resist mistreatment such as the strong compressive forces applied to the buckle when it is run over by the wheel of a vehicle. It is recognized that other embodiments can be used, such as that shown in FIG. 5 in its open condition and in FIG. 6 in its locked position.
In the embodiment of FIGS. 1-4, the cross members 30, 32 were attached to the legs 28 which extend perpendicularly to the line adjoining the eyes 26. In contrast, in the embodiment of FIGS. 5 and 6, a one-piece construction of the buckle is employed. In the embodiment of FIGS. 5 and 6, the end edge 36 replaces the first cross member 30 of the embodiment of FIGS. 1-4.
The offset produced in the embodiment of FIGS. 1-4 by attaching the cross members 30, 32 to the front surface 11 of the handle 15 is produced in the embodiment of FIGS. 5 and 6 by joggling the end portion 38 with respect to the plane of the handle 15, so that the rear surface 40 of the end section 38 lies in front of the rear surface 42 of the handle 15. In moving the handle 15 from its unlocked position in FIG. 5 to its locked position of FIG. 6, the handle is rotated in the direction of the arrow indicated in FIG. 5. During this movement, the upper portion of handle 15 passes through the loop in the rope as indicated in FIG. 5. The loop may be positioned in front of the handle 15, i.e., with the upwardly extending portions of the rope passing behind the handle, as shown in FIG. 5. When the loop is too small for the handle 15 to move through the loop in rotating to its locked position, it is, of course, necessary that the loop be positioned in front of the handle in its unlocked position.
In the embodiment of FIGS. 5 and 6, the retaining means is a strip of material lying between two apertures 44, 46 through the handle 15. It is recognized that in other embodiments, the retaining means could take the form of a bar-like member attached to the handle and spanning an opening in the handle, as in the embodiment of FIGS. 1-4.
FIG. 7 is a perspective view of another embodiment of the invention in which the buckle 10 is a one-piece construction with the belt or strap 12 being looped over the cross member 32 shown in phantom line drawing. As indicated, the opposite sides 24 of the handle 15 lie in one plane while the cross member 30, cross member 32 and the structural brace 33 lie in a plane which is offset from and lies behind the plane of the handle sides 24 as shown in FIG. 7. A pair of safety catches 48 may be formed at the upper end of the handle sides 24, as indicated, with the region between the handle sides being open.
A strap, generally indicated as 49, may pass through the eyes 26 formed in the handle sides 24 while upwardly extending strap portions 50 pass behind the handle 15 to a clasp 54. As indicated, the upwardly extending strap portions 50 are connected to a cross member 56 with looped ends 58 of the upwardly extending portions extending around the cross member. The cross member 56 may be joined to the clasp 54 in any convenient manner such that the cross member and clasp are structurally integral. The upwardly extending strap portions 50, being joined together through their connection to the cross member 56, form a loop which lies behind the handle 15 as shown in FIG. 7. In moving the buckle 10 to its locked position, as will be described, the handle 15 is merely pulled away from the loop formed by the upwardly extending strap portions 50 in the same general manner as described previously with regard to FIGS. 1-6.
FIG. 8 is a sectional view taken along the line 8--8 of FIG. 7 which illustrates the buckle 10 in its open position. As indicated, the cross members 30 and 32 lie in a plane which lies to the right of the plane of the handle sides 24 as shown in FIG. 8. The eyes 26 (see FIG. 7) pass through the handle sides 24 while the belt or strap 12 passes over the cross member 32. Accordingly, if a downward force is exerted on the belt or strap 12 with the buckle 10 in its position as shown in FIG. 8, the force tends to rotate the buckle in a clockwise direction from that shown in FIG. 8. As indicated, after passage of the upwardly extending strap portions 50 through the eyes 26, the strap portions which extend through the eyes are joined together by a connecting strap portion 52.
FIG. 9 is a sectional view, similar to FIG. 8, which illustrates the buckle 10 after rotation about a line through the eyes 26 (see FIG. 7) to its locked position. In its locked position, the buckle 10 is inverted with the strap 12 passing over the cross member 30 which now lies above the cross member 32. With the buckle 10 in its locked position, the plane of the cross members 30 and 32 now lies to the left of the plane of the handle sides 24 through which the eyes 26 extend (see FIG. 7). Accordingly, when a downward force is exerted on the strap 12 with the buckle 10 in the position shown in FIG. 9, the force tends to rotate the buckle in a counterclockwise direction from its position shown in FIG. 9. If desired, the belt ends 14 and 16 may extend through the opening between the handle sides 24 to engage the safety catches 48. However, is it not essential that the belt 12 pass through the opening between the handle sides 24 or that it engage the safety catches 48 in order for the buckle 10 to function as an overcenter device.
FIG. 10 is a sectional view taken along the line 10--10 of FIG. 7. As indicated, the plane of the cross member 32 about which the belt ends 14 and 16 are looped is offset from the plane of the handle sides 24 through which the eyes 26 extend. The cross member 30 lies in the same plane as the cross member 32 and the position of the cross member 32 as shown in FIG. 10 is, therefore, also indicative of the position of cross member 30. As indicated, the plane of the cross members 30 and 32 lies to one side of the plane of the handle sides 24 when the buckle 10 is in its open position as shown in FIG. 7. However, when the buckle 10 is rotated to its locked position as shown in FIG. 9, the plane of the cross members 32 and 30, in effect, flips over such that the plane of the cross members now lies on the opposite side of the plane of the handle sides 26. This explains the manner in which the buckle 10 functions as an overcenter device.
Thus, there has been described a locking buckle formed of flat plate stock and having a configuration which renders it highly resistant to damage caused by mistreatment.
The foregoing detailed description is illustrative of several embodiments of the invention, and it is to be understood that additional embodiments thereof will be obvious to those skilled in the art. The embodiments describe, herein, together with those additional embodiments, are considered to be within the scope of the invention. | A buckle of the type used to connect belts used for tying down cargo in vehicles. The buckle is formed of flat plate stock and has a structure adapted to withstand high compressive forces such as are applied to it when it is run over by loaded vehicles. The buckle operates on an overcenter principle, so that once it is locked further tension on the belts tends to keep the buckle locked. In using the buckle, initially the free end of one belt is threaded through the buckle and pulled to take up slack. The free end is jammed between the standing end of the belt and a portion of the buckle, preventing slippage. Next, the handle of the buckle is rotated approximately 180 degrees, which causes the standing part of the belt to be wound around the buckle, thereby placing the belt in tension. Towards the end of its throw, the handle of the buckle passes to an overcenter position, in which further tension in the belt locks the buckle more securely. A safety catch is provided to insure against accidental opening of the buckle in case the cargo shifts. |
FIELD OF THE INVENTION
This invention relates to an apparatus and method for providing very narrow linewidth patterns of deposited material on, or etched regions in, an insulating substrate, and more particularly to such a technique in which narrow linewidth features can be provided by using a very fine tip without the need for a highly conductive material in the substrate.
BACKGROUND OF THE INVENTION
Conventional lithographic techniques are well known in the manufacture of miniaturized electronic and magnetic circuits. In particular, photoresist layers are often used, where the photoresist layer is pattern-wise exposed and developed to provide a pattern which is then used for the deposition of a material or etching of the substrate on which the photoresist layer is located. The resolution obtainable in these photolithographic processes is limited by diffraction effects, which are in turn related to the wavelength of the light used in the exposure step.
In order to increase resolution, electron beam lithography is used. In this type of lithography, a deposited electron-sensitive resist layer is pattern-wise exposed, typically using an electron beam which is scanned across the resist layer and is turned on and off so as to form the desired exposure image in the resist layer. The resist is then developed in a manner similar to that used in photolithography. In electron beam lithography, resolution is limited primarily either by electron scattering effects in the material being radiated or by the diameter of the electron beam (if the beam diameter is too large). In particular, tightly focussed beams are provided by increasing the voltages that are used; however, increased energy beams lead to an increased energy of backscattered electrons, which have greater ranges and expose greater volumes of material. This in turn clouds the image produced by the electron beam exposure.
While it has been recognized in theory that electron scattering effects may be reduced by lowering the energy of the electrons in an electron beam, the minimum achievable beam diameter in conventional electron beam machines increases as the energy of the electrons in the beam is reduced. This occurs due to chromatic aberration in the magnetic and/or electronic lenses of such such apparatus, among other causes. Consequently, as the energy of the electrons in a conventional electron beam apparatus is reduced, the resolution actually deteriorates rather than improves because of the increasing beam diameter.
The need for high performance integrated devices and for further miniaturization has led to an improvement in providing such devices and circuits, as described in U.S. Pat. No. 4,785,189 by Oliver C. Wells, assigned to the present assignee. That reference recognizes that solutions to these two problems are not readily consistent since, if one of the resolution-limiting problems is corrected, the other is worsened. In order to overcome this, the reference utilized a different apparatus for providing a very narrow electron beam, the apparatus being a pointed tip from which electrons are emitted. Since the provision of a very narrow electron beam is achieved without large focussing voltages, the energies of electrons in the beam from the pointed tip are very small. This in turn solved the backscattering problem.
While a pointed tip or stylus is used in U.S. Pat. No. 4,785,189, such a technique and apparatus requires that the substrate contain a conductive layer in order to provide a return path for the tunneling current that is used to expose the electron-sensitive material. However, in the fabricaiton of many devices and circuits, substrates do not containn a conductive layer. Even if a conductive layer is present the insulating layer, which must be exposed, is often too thick to allow the passage of low energy electrons therethrough. Thus, while U.S. Pat. No. 4,785,189 is very useful for the exposure of very thin electron-sensitive resist layers or resist layers having a conductive layer located thereover, such a technique cannot be used where no highly conductive return path is provided for the tunneling electron current from the pointed tip, or stylus.
In a typical scanning tunnelling microscope (STM), a voltage of 0.1-1 volts is applied between the electron emitting tip and the conducting substrate, which is sufficient to drive a current in the nanoamp range continuously through the circuit. For a less highly conducting substrate return path, the currents are too weak to use to adjust the tip-to-substrate distance (Z) accurately. This is particularly apparent when the tip is to be scanned across the insulating substrate. In an STM, the pointed tip may be damaged if it has to be moved in a Z-direction to hunt for the substrate surface and then runs into the substrate surface. To solve this problem, the present invention uses a conductive pointed tip attached to a conducting cantilever to be able to accurately establish the desired tip-to-substrate distance even when the tip is scanned in the X-Y plane across the insulating substrate. This operation is similar to the movement of a pointed tip in an atomic force microscope (AFM) as described in U.S. Pat. No. 4,724,318.
Accordingly, it is a primary object of the present invention to provide an apparatus including a pointed tip and method for producing very narrow linewidths on substrates which do not include highly conductive layers serving as a current return path for electrons from the pointed tip.
It is another object of this invention to provide an apparatus including a pointed tip and method for affecting insulating materials, without the need for providing a highly conducting path through the insulating materials to the apparatus used to affect the insulating material.
It is another object of the present invention to provide an apparatus including a pointed tip, or stylus from which a very narrow beam of electrons can be emitted, and to utilize the narrow beam of electrons to affect an insulating material, there being no highly conductive return current path for said electrons.
It is another object of this invention to provide an apparatus and method for producing very-fine linewidth depositions on a highly insulating material or etched regions in the highly insulating material.
It is another object of the present invention to provide an improved technique which adapts the spatial resolution advantages possible with the use of the pointed tip or stylus to the provision of very narrow linewidth patterns on insulating materials of many thicknesses.
BRIEF SUMMARY OF THE INVENTION
In the practice of this invention, a pointed tip, or stylus, is used to emit electrons which travel to an insulating layer and cause effects thereon, there being no means for providing a highly conductive return current path for the emitted electrons. The pointed tip or stylus is comprised of a conductive material and is connected to a conductive spring or cantilever, which can be moved in X, Y or Z directions with respect to the insulating layer. The insulating layer can also be moved in X,Y and Z directions with respect to the pointed tip, or stylus. The spring or cantilever with the conductive pointed tip is attached to a voltage source for applying either a positive, negative or zero voltage to the pointed tip in order to effect the emission of electrons therefrom. Interferometer or other techniques as known in the art are used to determine the exact position of the pointed tip relative to the insulating layer. Thus, this apparatus has structure similarities to an atomic force microscope. In such an apparatus, a sharp point is brought close to a surface of a sample to be investigated and the forces occuring between atoms at the apex of the point and those at the surface layer cause the spring-like cantilever to deflect. Deflection of the cantilever is monitored as the sharp point is moved across the surface of the layer to be examined. In this manner a topographic or other image of the surface is obtained. In a prepared embodiment of the AFM, the pointed tip is vibrated at high frequencies to increase the signal to noise ratio, thereby increasing the accuracy of the Z-coordinate measurement.
In the present invention, the pointed tip and the spring-like cantilever are comprised of conductive materials so that a voltage can be applied to the pointed tip to cause electron emission therefrom. Since a highly conducting return current path is not required, and since tunnelling into a solid is not required, this invention can be used to provide high resolution depositions on or etched regions in insulating materials, over a wide range of thickness of the insulator.
The electrons ejected from a pointed tip into vacuum tunnel from the material of the tip into the vacuum and are then accelerated in the electric field surrounding the tip. When the electrons land on a surface, they have a range in the material depending on the electron energy. The electrons have a relatively long range at very low energies, which decreases to a minimum of (typically) 0.5 nm at an electron energy typically between 5 and 50 volts, and then increases again so that the range is about 10 nm for electrons of about 5000 volts.
When used in a direct-write mode, a gas capable of being dissociated or decomposed is located between the pointed tip and the insulating substrate or adsorbed on the insulating substrate. As an alternative, the insulating layer can be a resist layer which is electron-sensitive. A highly conducting substrate is not required, and the insulating resist layer or layers can be very thick. Another use of the present invention is for the localized charging of the insulator surface and then the exposure of the charged surface to an oppositely charged gas or particle cloud. Depending upon the gas or particle cloud, material will be deposited in the localized charged areas of the insulator, or these localized charged areas will be etched. Thus, in the practice of this invention, the advantages to be obtained by the very narrow beam width of the electrons emitted from a pointed tip are extended to allow utility with materials which could not heretofore be addressed with such apparatus, viz, insulating materials and particularly those insulating materials having thicknesses in excess of about 10 nm.
The pointed tip in this invention may also be used as a source of positively charged atoms or molecules. A material such as gallium metal may be ionized at the pointed tip and accelerated in the field of the tip to produce a fine ion beam.
These and other objects, features, and advantages will be apparent from the following more particular description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of an apparatus sufficient to carry out the present invention, the apparatus including a pointed tip or stylus located in close proximity to an insulating substrate.
FIG. 2A-2C illustrate a particular use of this invention to pattern-wise expose an electron-sensitive resist layer in a process wherein an X-ray mask is formed.
FIG. 3 illustrates the use of this invention in a direct-write mode wherein fine line depositions are produced on an insulating substrate.
FIGS. 4A and 4B illustrate an additional use of this invention in which localized charged regions of an insulator can be contacted to produce localized etched regions in the insulator surface.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates an apparatus which can be used to practice the present invention. This apparatus includes a conductive pointed tip or stylus 10 connected to a spring-like cantilever 12. A small reflective index mark 14 can be optionally provided on the cantilever for use in fine Z-positioning. Using well known interferometric means a light beam, depicted by arrow 16, will be reflected from index mark 14 and can be used to exactly position the cantilever and the pointed tip 10. A piezoelectric member 18, or members, are located on the end of cantilever 12 and are used for X,Y and Z positioning of the pointed tip 10 with respect to the substrate surface. A voltage source 20 is connected via lead 22 to the spring-like cantilever 12. Source 20 can be used to provide positive, negative or zero voltages at the apex of tip 10.
The pointed tip 10 can be moved across the substrate 24 in contact with substrate 24. When the tip is in the desired X-Y position, the pointed tip 10 can be positioned at a set distance above the substrate 24, which in this case is illustrated as a resist layer 26 on a thick insulator layer 28. Resist layer 26 can be any of the well known electron-sensitive resist materials. Piezoelectric member 30, or members, are located behind insulating layer 28, and are used for X,Y and, Z optionally, positioning of the substrate 24. X,Y and Z controllers 32 are connected to piezoelectric members 18 and 30 in order to provide proper positioning of the substrate 24 and the pointed tip 10, both laterally in the X,Y plane and in the Z-direction.
Pointed tip 10 is comprised of a conducting material, or a conductive coating layer, as is the spring-like cantilever 12. Suitable materials for the pointed tip 10 include a metal such as tungsten, or a highly doped conductive semiconductor material, such as a boron-doped silicon member which can be machined in very precise dimensions, or boron-doped diamond. The cantilever 12 can be comprised of a conducting metal, such as gold, or a highly doped silicon semiconductor. The advantage of using a doped semiconductor is that micromachining techniques can be utilized to provide an integral pointed tip 10-cantilever 12 using known lithographic techniques. Examples of such techniques are shown in U.S. Pat. No. 4,668,865 and the references described therein. This patent is incorporated herein by reference with respect to its teaching of a semiconductor pointed tipcantilever structure.
The dimensions of the pointed tip 10 are also well known in the art, wherein a tip having a radius of a curvature of about 1 nm can be obtained. This type of tip is described in U.S. Pat. No. 4,668,865, and in U.S. Pat. Nos. 4,724,318 and 4,343,993. A suitable example of a X-Y positioning technique utilizing piezoelectric elements is shown in more detail in U.S. Pat. No. 4,422,002 as well as in IBM Technical Disclosure Bulletin, Vol. 27, No. 10B, page 5976 (1985).
While a tunneling current is not required in the present invention, it may be advantageous to provide vibration attenuation devices if the pointed tip is to be carried at very close distances (in the nm range) from the insulator surface. Various attenuation devices have been described in the aforementioned references, and also in IBM Technical Disclosure Bulletin, Vol. 27, No. 5, page 3137 (1984).
The apparatus of FIG. 1 can be used to affect an insulating layer 26 to provide fine-line depositions thereon, or etching of fine-line patterns in the insulator 26. It is not necessary to have a tunneling current between pointed tip 10 and substrate 24, and it is therefore not necessary to provide a substrate including a highly conducting current return path. Because of this, any type of insulator can be used as the work piece, where such insulators include electron-sensitive resist materials and other non-electron-sensitive materials, such as quartz, polymers, and typical insulating materials such as silicon dioxide and silicon nitride. Depending on the separation between the pointed tip 10 and the surface of the insulator 26, low voltage electrons can be produced which will travel to the surface of the insulator 26. These electrons will be produced when a voltage is applied from source 20, utilizing the switch S. When the separation between the pointed tip 10 and the surface of insulator 26 is increased to more than about 1 nm, field emission is used to emit electrons from the apex of pointed tip 10. It has been found that it will be possible to dissociate molecules on the surface of insulating layer 26 by bombardment with electrons having energies greater than about 5 eV. If the surface of insulator 26 is clean, then the molecules of certain gases will be disassociated at the clean surface. If there is a residue, such as H or F atoms or molecules on the surface on insulator 26, a higher electron energy (greater than 30 eV) will be required to desorb these atoms or molecules. In such a situation, the voltage V applied to the pointed tip is increased so that electrons in the beam emitted from the apex of tip 10 will have electron energies greater than about 30 eV. Once the H or F residue is removed, further reactions desired at the surface of insulator 26 can be achieved.
Various embodiments will be shown wherein the invention can be used to expose a thick resist layer or a thin resist layer located on an underlying thick insulating substrate, for example to manufacture an X-ray mask. Other embodiments will illustrate the use of the apparatus of FIG. 1 to deposit fine-line patterns on insulators and to etch fine-line regions in an insulator layer.
FIGS. 2A-2C illustrate some steps in the manufacture of an X-ray mask. In FIG. 2A, a thick (approximately 500 microns) silicon layer 34 has been doped and etched using the openings in the thin resist layer 40 as a mask to provide regions 36A, 36B, and 36C of lesser thickness. A two-layer resist is located over the silicon layer 34, comprising a thick resist layer 38 and a thin layer resist layer 40. These resist layers are to be patterned for the selective deposition of an X-ray opaque material, such as a thick layer of gold.
In FIG. 2B, the thin resist layer 40 is exposed to electrons from pointed tip 10, after which it is developed to leave openings therein. The thick resist layer 38 (to be used to provide a sufficiently thick gold layer) is then anistropically etched using the openings in the thin resist layer 40 as a mask to provide openings 42 which extend to the surface of silicon layer 34. An X-ray opaque material, such as gold layer 44, is then deposited onto the patterned resist layers, and onto the exposed surfaces of silicon layer 34, as shown in FIG. 2B.
After a lift-off process which removes the resist layers 38 and 40, as well as the gold layer located thereon, the structure of FIG. 2C is obtained. This structure includes patterned gold layer 44 located on the silicon layer 34, where the silicon regions 36 are sufficiently thin that X-rays will pass therethrough unless blocked by the gold layer 44. Thus, a structure is provided in which very fine gold layer patterns are produced by electron beam techniques but wherein high voltages are not required to focus the electron beam. Further, the pointed tip of FIG. 1 can be used to provide the narrow electron beam at low voltage, even though no highly conductive return current path is required. Since the entire thick resist layer 38 is insulating, the fine structure of FIG. 2C cannot be provided at low electron beam energies with apparatus existing prior to this invention.
FIG. 3 illustrates the use of the present invention to provide a fine-line deposition directly on an insulating substrate in a direct-write process. This technique has some similarities to that shown in U.S. Pat. No. 4,550,257, but is significantly different in that the substrate does not provide a highly conducting current return path between the pointed tip 10 and the substrate. For ease of illustration, the same reference numerals will be used as were used in FIG. 1, if the referenced feature has the same function. In FIG. 3, the layer 26 may be an insulator which is not a resist layer. A gas, indicated by the wavy lines 46, is located in the vicinity of the pointed tip 10, and is present between the apex of the pointed tip and the insulation surface 26. When a voltage is applied from source 20 (FIG. 1) field emission can be used to create electrons which travel to the insulator surface and dissociate or decompose gas molecules located on or near the surface of insulator 26. This causes materials to be deposited from the dissociated gas molecules. An example is a gas such as tungsten hexafluoride (WF 6 ) or boron trifluoride (BF 3 ). Other gases that can be used to deposit metals include trimethyl aluminum Al(CH 3 ) 3 and tungsten hexacarbonyl W(CO) 6 . It is also possible to deposit other than metals on the surface of insulator 26 using the present invention. For example, a gas such as disilane (Si 2 H 6 ) can be dissociated to deposit silicon.
FIGS. 4A and 4B illustrate a technique in which the apparatus of FIG. 1 is used to etch very fine regions in the surface of the insulator 26. In this embodiment, the electrons emitted from pointed tip 10 cause a negative charging of localized regions in the surface of insulator 26, as illustrated by the "minus" marks 48. By scanning pointed tip 10 across the surface of insulator 26, localized trapping of the electrons occurs in the surface of layer 26. If an oppositely charged gas, plasma or particle cloud, indicated by wavy lines 50 in FIG. 4B, is brough to the surface of layer 26, the localized charged areas can be etched to produce the fine-line etched regions 52. An example of an oppositely charged gas or particle cloud which can be used to etch a negatively charged region in an insulator is (CF 3 ) + .
As an alternative in the technique illustrated in FIGS. 4A and 4B, the oppositely charged gas or particle cloud can be one which will react with the localized charged regions 48 to cause decomposition or dissociation of the gas or particle cloud a deposit a species only in the area showing the localized charges. An example of such a charged gas is (WF 5 ) + ).
It will be recognized by those of skill in the art that charging of the surface of an insulator may not be desired in all cases. In order to eliminate accumulated electrons, the polarity of the voltage source 20 (FIG. 1) can be changed to attract any charging electrons located on the insulator surface. Thus, the net charge transferred to the insulator surface over time may be zero.
In the practice of this invention, it has been found that the applied voltages can be very small, typically less than 100 volts, and more typically less than about 40 volts. Because the electron beam is so narrow and because only low voltage electrons need be utilized, problems associated with conventional electron apparatus such as a scanning electron microscope (SEM) are avoided. Further, the limitations attendant with a scanning tunneling microscope type of apparatus, as utilized in aforementioned U.S. Pat. Nos. 4,550,257 and 4,785,189, are avoided since a tunneling current and a higly conducting current return path are not required. The pointed tip of this invention can be used to provide high resolution patterns on insulating substrates with resolutions not obtainable by conventional SEM-type apparatus. For example, a 5000 V SEM cannot expose a resist layer with a resolution of 100 Å because the electron beam cannot be focussed to 100 Å at these voltages. In the apparatus of the present invention however, a tip voltage of 5000 V can be used to expose a resist layer with 100 Å resolution.
In contrast with a conventional STM, the present invention can be used to scan an insulating substrate where the impedance of the entire current path is very high, being about 10 10 ohms and larger. With a conventional STM, the current necessary for feedback control having scanning would not be obtainable when the current path has these high impedances.
While the invention has been shown with respect to particular embodiments thereof, it will be apparent to those of skill in the art that variations can be made therein without departing from the spirit and scope of the present invention. For example, those of skill in the art will foresee additional applications of this technique to produce many different structures, some of which may be novel. | A method and apparatus for producing fine line patterns on insulating surfaces utilizing a conductive spring-like cantilever having a pointed tip which is in proximity to the surface to be affected. Electrons emitted from the tip travel toward the insulator surface and cause changes therein or affect molecules located in the proximity of the insulator surface. Tunneling current is not required, and a highly conducting return current path for electrons through the insulator is not necessary. The incident electrons can be used to provide patterned, narrow-width features either by deposition of a material onto the insulator surface, or by producing etching in localized regions of the insulator surface, or by changing the insulator surface so that it can be etched. |
CROSS REFERENCE TO RELATED APPLICATIONS
This is a Divisional Application based on Ser. No. 09/134,061, filed Aug. 13, 1998, now U.S. Pat. No. 5,958,744 which is a continuation-in-part of Provisional Application Ser. No. 60/056,013, filed Aug. 18, 1997 entitled IMPROVEMENTS IN SUCCINIC ACID PRODUCTION AND PURIFICATION, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The invention relates generally to production and purification of organic acids and more particularly to an improved processes for the production and purification of succinic acid from succinate salts that result from the fermentation of carbohydrates.
Succinic acid [110-15-6] (butanedioic acid), C 4 H 6 O 4 , is a naturally occurring constituent in plant and animal tissues, see, e.g., Winstrom, L. O. “Succinic Acid and Succinic Annydride”, Kirk and Othmer Encyclopedia of Chemical Technology, Vol. 1, 4 th Ed., (1978), the contents of which are incorporated herein by reference. It has therefore been affirmed as GRAS by the FDA. This status enables it to be used for various purposes, such as, but not limited to, a flavor enhancer, a pH control agent in foods such as condiments and for use in meat products. It is also widely used in scientific applications including uses in radiation dosiometry, standard buffer solutions, agriculture, foods, medicines, cosmetics, textiles, plating and waste-gas scrubbing.
Numerous patents discuss the production of carboxylic acids, such as succinic acid via fermentation. (See, e.g. U.S. Pat. No. 5,168,055 to Datta, the contents of which are incorporated herein by reference.) However, a major factor involved in industrial scale production using fermentation is the cost involved in downstream processing necessary to concentrate and purify the product. For example, it has been determined that fermentation proceeds best at an approximately neutral pH. However, the acid produced will eventually lower the pH. In order to avoid low pH fermentation broths that are injurious to the microorganisms driving the fermentation process, the pH of the broth should be raised by the addition of a base. However, the added basic material generally reacts with the acid and leads to the production of a salt of the carboxylic acid rather than the desired free acid product itself.
Thus, downstream processing typically involves both conversion of the salt into the free acid and the purification of the acidified product. Additionally, insoluble materials from the fermenter, such as the dead cells, generally need to be removed. Therefore, for fermentation to be economically viable, a technique for the production of relatively pure acid and an efficient recovery process is desirable.
U.S. Pat. No. 5,168,055 to Datta et al., the contents of which are incorporated herein by reference, proposed a process that combines the fermentation of carbohydrates to produce calcium succinate and the subsequent conversion to and purification of the succinic acid product. The succinate salt is acidified into the pure acid with sulfuric acid and gypsum, CaSO 4 , is produced as a by-product. The succinic acid produced is then processed through a series of steps designed to purify the product. However, it has been found that for every mole of succinic acid product produced, an equal amount of gypsum by-product is produced. This gypsum by-product has little value, in part, because the odor and color contamination from the fermentation process renders it unsuitable for commercial use. In addition, reagents such as calcium oxide or calcium hydroxide and sulfuric acid are consumed and are not regenerated within the process.
U.S. Pat. No. 5,143,834 to Glassner et al., the contents of which are incorporated herein by reference, proposes a similar combination of fermentation and purification processes for the production of succinic acid from disodium succinate that is formed in the fermentation step. Succinic acid is produced by using a combination of electrodialysis and water splitting steps that ultimately separate the base, and produce pure acid. Further purification is achieved by passing the product stream through a series of ion-exchange columns. However, this process has disadvantageously high costs, such as membrane costs and the electrical energy costs associated with electrodialysis.
U.S. Pat. No. 5,034,105 to Berglund et al., the contents of which are incorporated by reference, proposes a process for obtaining a carboxylic acid of high purity by using water splitting electrodialysis to convert an undersaturated aqueous solution of disodium succinate into a supersaturated solution of succinic acid that facilitates in crystallizing the product carboxylic acid. However, this process also suffers from the high costs associated with the Glassner et al. patent.
Accordingly, it is the objective of this invention to provide an improved method of producing and purifying carboxylic acids, such as succinic acid, which result from fermentation processes.
SUMMARY OF THE INVENTION
Generally speaking, in accordance with the invention, a highly efficient process for the production and recovery of pure succinic acid from a succinate salt that involves minimal use of additional reagents, and produces virtually no waste by-products, and permits internal recycle of the base and acid values, is provided. The method involves the formation of diammonium succinate, either by using an ammonium ion based material to maintain neutral pH in the fermenter or by substituting the ammonium cation for the cation of the succinate salt created in the fermenter. The diammonium succinate can then be reacted with a sulfate ion, such as by combining the diammonium succinate with ammonium bisulfate and/or sulfuric acid at sufficiently low pH to yield succinic acid and ammonium sulfate. The ammonium sulfate is advantageously cracked thermally into ammonia and ammonium bisulfate. The succinic acid can be purified with a methanol dissolution step. Various filtration, reflux and reutilization steps can also be employed.
Accordingly, it is an object of the invention to provide an improved method and system for producing and purifying succinic acid.
Another object of the invention is to provide an improved method for producing and purifying succinic acid which does not consume substantial quantities of reagents nor produce substantial quantities of by-products.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and drawings.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the composition possessing the features, properties, and the relation of constituents, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:
FIG. 1 is a schematic block process flow diagram for the production of succinic acid from diammonium succinate, in accordance with a preferred embodiment of the invention;
FIG. 2 is a schematic block process flow diagram for the production of succinic acid from disodium succinate, in accordance with another preferred embodiment of the invention;
FIG. 3 is a graph showing change in succinic acid solubility (g/g—water) in aqueous ammonium bisulfate solutions as a function of pH; and
FIG. 4 . Is a graph showing change in succinic acid yield in aqueous ammonium bisulfate solutions as a function of pH; and
FIG. 5 is a graph showing the change in solubility of ammonium sulfate in methanol-water solutions.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention provides an advantageous method of producing and purifying succinic acid, based, in part, on the realization that an ammonium sulfate by-product of the purification method can be recycled, to yield a method of production which is substantially free of unwanted by-products and does not require substantial consumption of reagents.
Certain biological materials will produce succinic acid upon fermentation. As acid is produced, the pH of the fermentation broth will steadily decrease, until conditions become intolerable for the biological material. The fermentation broth is advantageously maintained at a pH of over about 6, more preferably at about 7. One way of increasing yield, is to raise the pH (i.e., maintain a substantially neutral pH) by the addition of a base. However, the base will generally react with the succinic acid formed and yield a succinic acid salt, formed of the cation of the base and the succinate anion.
A first step in the production and purification method is to produce diammonium succinate. This can be produced by adding basic material formed with an ammonium ion. A second route to diammonium succinate is to add a different base to the fermentation broth, such as sodium hydroxide and then substitute the ammonium ion for the sodium ion. While most bases are suitable, it has been found that divalent bases, such as calcium hydroxide can lead to certain solubility problems downstream. Accordingly, the monovalent bases (e.g., alkali metal bases), such as sodium hydroxide and potassium hydroxide are preferred.
The salt of the base, e.g. disodium succinate, is then converted to diammonium succinate through ion substitution, for example, by the addition of ammonia. In one preferred embodiment, a disodium succinate slurry is combined with carbon dioxide and ammonia, to yield a slurry including diammonium succinate with sodium bicarbonate as a by-product.
After the diammonium succinate is formed, it is reacted with sulfate ions from a sulfate ion source to form ammonium sulfate and pure succinic acid. This can be accomplished by the addition of sulfuric acid, as the reaction is advantageously performed at a pH of less than 2, preferably between 1.5 and 1.8 to form crystalline succinic acid. Succinic acid has extremely low solubility in aqueous solutions with a pH below 2, particularly in the range of 1.5 to 1.8. In a preferred method, ammonium bisulfate is combined with the ammonium succinate to yield free succinic and ammonium sulfate. The succinic acid can be filtered from the product stream including the ammonium sulfate and further purified by the addition of methanol. Any remaining sulfates will be insoluble in methanol, whereas the succinic acid will be substantially dissolved in the methanol. After methanol is evaporated, substantially pure crystalline succinic acid remains. The evaporated methanol can be condensed and reused.
The ammonium sulfate can be readily cracked at a temperature of about 300° C., to form a combination of ammonium bisulfate and ammonia gas. A sulfate salt of the base can be another by-product. In the two-step conversion, sodium bicarbonate given off during the conversion of disodium succinate to diammonium succinate can be recycled into the fermenter to maintain a neutral pH and thereby decrease the need for added sodium hydroxide.
As examples of providing advantageous fermentation processes for producing high purity carboxylic acids and improved purification methods, a series of operations for converting diammonium succinate (either from the fermenter or from the conversion of disodium succinate) to succinic acid and for crystallizing the acid to obtain a high purity product are provided. These operations are also schematically presented in the flow diagrams of FIGS. 1 and 2, for added clarity. In the methods of the preferred embodiments, the use of additional reagents are minimized and the amount of waste by-products are relatively low. In addition the reagents in certain preferred embodiments are regenerated within the process and only makeup amounts are needed.
In preferred embodiments of the invention, two important physical attributes are employed to separate succinic acid from other process material. First, the minimal solubility of succinic acid in water in the presence of sulfuric acid or hydrogen sulfate ions is used to separate succinic acid from the sulfates. Second, sulfates are virtually insoluble in methanol, although methanol is a good solvent for succinic acid. Therefore, this attribute is used to separate the sulfates for recycling and to further purity succinic acid without sulfate impurities.
Aspects and attributes of the invention will be exemplified with reference to the following examples, which are provided for purposes of illustration only, and are not intended to be construed in a limiting sense.
EXAMPLE 1
The Production of Succinic Acid from Diammonium Succinate
Referring generally to FIG. 1, carbohydrates (such as corn derived carbohydrates, such as glucose) are anaerobically fermented in Fermenter 101 with a microorganism that is capable of or genetically engineered to produce succinic acid. One especially suitable organism is identified as E. Coli AFP-111 (American Type Culture Collection ATCC 202021) Fermenter 101 is run under controlled conditions with the required biomass nutrients, carbon dioxide, and ammonia to produce a high yield of succinate. (See, e.g. U.S. application Ser. No. 08/556,805, filed Nov. 2, 1995, the contents of which are incorporated herein by reference). A pH of over 6.0, preferably at about 7 is preferred.
Recycled ammonia (Stream 18 ) from a thermal cracker 102 is advantageously added to fermenter 101 to neutralize the succinic acid produced by the microbe to diammonium succinate. Additional ammonia, if required, can be made up by the addition of ammonium hydroxide. The neutralization is carried out to maintain a substantially neutral pH where anaerobic fermentation is commonly most productive. The output from fermenter 101 will generally be a dilute (6-10% w/w) aqueous diammonium succinate solution (Stream 1 ) that contains a number of insoluble impurities such as dead cells and proteins.
Stream 1 is preferably filtered with a filter 103 to remove the insolubles. The filtrate (Stream 2 ) will generally be a dilute (˜10% w/w) solution that is preferably concentrated to maximize the efficiency of the subsequent separation processes. An evaporator, such as a multi-effect evaporator 104 can be used to concentrate the solution to about 25-30% w/w ammonium succinate. This concentrated solution, with a pH of about 7.0 (Stream 3 ), can then be fed into a crystallizer 105 to which a source of sulfate ions, here, recycled ammonium bisulfate (Stream 17 ) is added. This addition serves to reduce the pH of the solution to approximately 1.5-1.8. At this low pH, the succinate ion is protonated by ammonium bisulfate to form ammonium sulfate and succinic acid.
(NH 4 ) 2 A+2NH 4 HSO 4 =H 2 A=2(NH 4 ) 2 SO 4
where A=succinate anion=(HOOC) (CH 2 ) 2 (COOH)
Succinic acid crystallizes due to its low solubility at this pH. The desired pH (under 2, preferably 1.5-1.8) can also be obtained by a makeup stream of fresh ammonium bisulfate or sulfuric acid. The amount of ammonium bisulfate added is important to maintain the pH between 1.5 and 1.8 because optimal yield is generally obtained in this pH range. The resulting slurry (Stream 4 ) can then be filtered with a filter 106 and washed.
The crystalline succinic acid (Stream 5 ) is then advantageously dissolved in methanol (Stream 10 ) in a methanol purification station 107 to separate succinic acid from any sulfates that may co-crystallize with succinic acid. The sulfates (Stream 8 ), if any, are relatively insoluble in methanol and can be filtered out and combined with Stream 12 for thermal cracking. It is believed that other alcohols can be used, but that methanol yields the best results. The methanol from the succinic acid/methanol solution (Stream 6 ) can then be evaporated in an evaporator 108 to produce pure crystalline succinic acid (Stream 7 ). The evaporated methanol (Stream 9 ) can be collected and stored for recycling in a methanol storage tank 109 .
Methanol (Stream 15 ) can be added to the filtrate (Stream 11 ) which contains ammonium sulfate and residual succinic acid, ammonium bisulfate, and sulfuric acid in a crystallizer 110 . The methanol causes substantially all the sulfates to crystallize out of solution. The crystallized sulfates are advantageously separated by filtration 110 . This crystallization occurs because the sulfates are virtually insoluble in methanol. This step enables the separation of the sulfates from any residual succinic acid, and can reduce the presence of charred organics in the subsequent sulfate cracking operation.
The sulfates (Stream 12 ) containing mostly ammonium sulfate and some residual ammonium bisulfate and sulfuric acid can then be fed into thermal cracker 102 which can be maintained at about 200-310° C., preferably about 290-310° C., most preferably about 300° C. At this temperature range, ammonium sulfate cracks to produce ammonia and ammonium bisulfate. Formation of sulfuric acid is also possible.
(NH 4 ) 2 SO 4 →NH 4 HSO 4 +NH 3
Ammonium bisulfate, the residual sulfuric acid and residual uncracked ammonium sulfate (Stream 17 ) can be recycled back to succinic acid crystallizer 105 . Ammonia can be fed back to fermenter 101 to provide the base value for neutralization (Stream 18 ).
The filtrate from crystallizer (Stream 13 ) containing methanol, water and residual succinic acid can be distilled in a methanol separator 111 , to separate methanol from the aqueous media. The methanol (Stream 14 ) can be stored for recycling or fed directly to tank 109 . The bottom product of the distillation (Stream 16 ), which is an aqueous solution containing residual succinic acid and some sulfates can be combined with Stream 2 for concentration.
Crystalline succinic acid is substantially the only product generated by this process.
EXAMPLE 2
Production of Succinic Acid from Disodium Succinate
Referring generally to FIG. 2, carbohydrates, such as corn derived carbohydrates, such as glucose, are anaerobically fermented with a microorganism that produces succinic acid. The fermenter is advantageously run under controlled conditions with the required biomass, nutrients, carbon dioxide, and a base to produce a high yield of succinate. The same stream numbers and other reference numerals recited with reference to Example 1 and FIG. 1 will be repeated where the stream or functional element in FIG. 2 is similar in nature to that of FIG. 1, even if the two are not exactly identical.
Recycled sodium bicarbonate (Stream 2 b ) is added to fermenter 101 to maintain a neutral pH broth for optimum production. The bicarbonate for the anaerobic conditions of the fermenter is also provided by this stream. Additional base, if required, can be made up by the addition of sodium hydroxide, for example. Bases with other cations besides sodium can be used. However, it has been observed that the monovalent cations such as potassium, yield the best results. The output from fermenter 101 will typically be a dilute (6-10% w/w) aqueous disodium succinate solution (Stream 1 ) that contains a number of insoluble impurities such as dead cells and proteins.
Stream 1 should be filtered to remove the insolubles with filter 103 . The filtrate (Stream 2 ) is preferably concentrated to maximize the efficiency of the subsequent separation processes. Multieffect evaporator 104 can be used to concentrate the solution to near saturation (50% w/w). This concentrated solution, having a pH of generally about 7.0 (Stream 2 a ), is fed into a crystallizer 105 ′ to which recycled ammonia (Stream 18 ) and carbon dioxide can be added. This will convert the disodium succinate to diammonium succinate (Stream 3 ) with the formation of solid sodium bicarbonate (Stream 2 b ). The conversion of disodium succinate to diammonium succinate in crystallizer 105 using ammonia and carbon dioxide is a modification of the Solvay process used to produce sodium carbonate (See Rauh, Supra, the contents of which are incorporated herein by reference.).
Na 2 A+2NH 3 +2H 2 CO 3 =(NH 4 ) 2 A+2NaHCO 3
where A=succinate anion=(HOOC) (CH 2 ) 2 (COOH)
Solid sodium bicarbonate (Stream 2 b ) is advantageously recycled back into the fermenter as the base reagent.
As stated above, the streams in Example 2 are substantially the same as those of Example 1, with the goal of producing diammonium succinate. However, one difference is in stream 18 . In FIG. 2, ammonia produced by cracking (Stream 18 ) is recycled for the conversion of disodium succinate to diammonium succinate. In Example 1, the ammonia of stream 18 is recycled to the fermenter.
Diammonium succinite from crystallizer 105 ′ is converted to crystalllized succinic acid in crystallizer 105 by the addition of NH 4 HSO 4 (Stream 17 ) from thermal cracker 102 .
Crystalline succinic acid and some sodium bisulfate (by-product) is produced in this process.
The following experiments were performed to demonstrate the feasibility of the processes described above.
EXAMPLE 3
Determination of the Succinic Acid Solubility in Aqueous
Ammonium Bisulfate Solutions at 23° C. (Experiment I)
This example demonstrates an optimum pH range to obtain the maximum yield for succinic acid in crystallizer 105 .
20 g of succinic acid was slurried in 50 ml of water. The slurry was neutralized (pH=7) by adding 29 ml of 58% ammonium hydroxide. The total volume of this solution was 87 ml. Five 20 ml fractions, each containing 4.6 g of succinic acid, were prepared from the solution. The pH of the five fractions was adjusted with ammonium bisulfate to determine the solubility of succinic acid in aqueous ammonium bisulfate solutions. The results are presented in FIGS. 3 and 4.
The data suggests that the optimum pH range for maximum yield is 1.2 to 2.5, preferably below 2, more preferably about 1.5-1.8.
EXAMPLE 4
Determination of Ammonium Sulfate Solubility in Methanol-Water Solutions at 23° C. (Experiment II)
Ammonium Sulfate in excess was slurried for 24 hr. in methanol-water solutions of different proportions. Residual weight determinations resulted in the solubility curve given in FIG. 5 . The data suggests that sulfates are virtually insoluble in methanol-water solutions with high methanol content.
EXAMPLE 5
Determination of Ammonium Sulfate Solubility in Water at 23° C. (Experiment III)
Ammonium sulfate in excess was slurried in water for 24 hr. The solubility calculated based on the residual weight was 43.8% w/w.
EXAMPLE 6
Preliminary Process Simulation
Operations involving Streams 3 , 4 , 5 , 11 , 12 , 13 and 15 in FIGS. 1 and 2 were simulated based on the data collected in Experiments I, II and III. From Experiment I, a pH value of 1.6 was chosen as the target pH for the crystallization of succinic acid. From Experiment II, 80% w/w methanol solution was chosen as the target methanol-water ratio for the crystallization of sulfates. Using the results of Experiment III, the initial concentration of ammonium succinate was chosen such that there would have been sufficient water to solubalize ammonium sulfate produced in the conversion of ammonium succinate into succinic acid. This precaution was taken to minimize contamination of succinic acid by sulfates.
Stream 3 : An aqueous solution containing 25.4 g of ammonium succinate and 61.3 g of water (28.6% w/w, ammonium succinate) was prepared. Stoichiometrically, 25.4 g of ammonium succinate is expected to produce 20 g of succinic acid.
Ammonium bisulfate was added, stepwise, to adjust the solution pH to 1.6. The total amount of ammonium bisulfate added was 38.5 g. According to FIGS. 3 and 4 , the ammonium bisulfate requirement is 41.4 g. The agreement between the added amount and the required amount is reasonable.
Stream 5 : The above pH adjustment resulted in a succinic acid slurry. The slurry was filtered and the crystalline succinic acid was dried at 70° C., overnight. According to FIG. 3, at 89% yield, Stream 5 should have produced about 17.8 g of succinic acid. However, the actual amount was 18.7 g suggesting the possibility of sulfate contamination. Elemental analysis for sulfur and nitrogen indicated the presence of approximately 0.5 g of sulfates in the product. Since a pure product is desirable, using more water in Stream 3 to keep sulfates soluble was deemed advisable. In addition, a purification step using methanol was incorporated (Streams 5 and 10 ).
Streams 11 and 15 : 245 g of methanol was added to the filtrate (Stream 11 ) from the succinic acid filtration. Methanol was added such that the mixed solvent composition corresponded to the predetermined 80% w/w methanol solution. This produced 38.4 g of crystalline sulfates. The expected amount of sulfates was 41.7 g. The discrepancy between the experimental yield and the calculated yield is not unreasonable.
EXAMPLE 6
Thermal Cracking of Ammonium Sulfate
The conversion of ammonium succinate to succinic acid using ammonium bisulfate produces ammonium sulfate. Thermal cracking of ammonium sulfate, in turn, produced ammonium bisulfate that can be recycled for use in succinic acid crystallization.
A rotary tube furnace was used for thermal cracking. The furnace was attached to an aspirator to vent the effluent gasses. The rotary tube furnace was preheated to 300° C. 20 g of ammonium sulfate was cracked for 1 hr and 17.8 g of cracked sulfates were collected. Stoichiometrically, 17.4 g of ammonium bisulfate is expected from 20 g of ammonium sulfate. On a mass basis, the experimental amount and the calculated amount was in agreement. Therefore, these conditions were deemed appropriate for cracking of ammonium sulfate.
Based on the results presented above, a process for the separation of succinic acid was simulated between Streams 3 and 17 . Three cycles of the process were conducted.
EXAMPLE 7
Determination of Succinic Acid Solubility in Methanol at 23° C.
Succinic acid in excess was slurried in methanol for 24 hr. The solubility was calculated based on the residual weight was 16.5 g of succinic acid in 79 g of methanol.
The following represents a process simulation, which is presented for purposes of illustration only and is not intended to be construed in a limiting sense.
EXAMPLE 8
Cycle 1:
A 25.6% w/w aqueous solution of ammonium succinate (Stream 3 ) was prepared by neutralizing a slurry containing 20 g of succinic acid and 55 g of water with 27.5 g of 58% w/w ammonium hydroxide.
H 2 A+2NH 4 OH=(NH 4 ) 2 A+2H 2 O
where A=succinate anion=(HOOC) (CH 2 ) 2 (COOH)
The ammonium succinate solution could have been prepared by dissolving 25.4 g ammonium succinate in 74 g of water.
The aqueous solution of ammonium succinate, with a pH of 7.0, was taken in a crystallizer and 39 g of ammonium bisulfate was added, resulting in a pH adjustment to 1.6 and the crystallization of succinic acid.
The resulting slurry (Stream 4 ) was filtered. The separated crystalline succinic acid (Stream 5 ) was dried overnight at 70° C. The dry weight was 16.5 g.
The crystalline succinic acid (Stream 5 ) was dissolved in 79 g of methanol (Stream 10 ) to separate the succinic acid from any sulfates that may have co-crystallized with succinic acid. The undissolved sulfates (Stream 8 ) were filtered, dried and stored for thermal cracking. The dry weight of the sulfates was 0.9 g. Therefore, the weight of the succinic acid dissolved in methanol was 15.6 g. This amount corresponds to a yield of 78% (Stream 7 ). The low yield was expected since this was the initial cycle.
Two hundred eighty six grams of methanol (Stream 15 ) was added to the filtrate (Stream 11 ) containing ammonium sulfate and any residual succinic acid, ammonium bisulfate, and sulfuric acid in a crystallizer. The resulting slurry was filtered. The crystalline sulfates were dried overnight at 70° C. The dry weight was 40.3 g at a yield of 90.1%. The theoretical yield was 93.6%.
The sulfates (Stream 12 ) containing mostly ammonium sulfate and some residual ammonium bisulfate and sulfuric acid were added to a thermal cracking unit maintained at 300° C. for 50 minutes. During the cracking process, the molten sulfates turned black in color, indicating the presence of charred organic material. The molten sulfates were cooled to room temperature. During cooling, 50 ml of water was added to dissolve the sulfates. The solution containing the charred material was filtered with a 0.2 micron filter. The charred material was discarded. The clear solution was evaporated down to about 40 ml to concentrate the sulfates. During evaporation, some of the sulfates were lost due to an accidental spill. 190 g of methanol was added to the remaining solution. The resulting sulfate slurry was filtered and then dried at 70° C., overnight. 17.8 g of sulfates were recovered.
The filtrate was distilled to separate methanol and 166 g of methanol was collected and stored for recycling. This step, involving the separation of the sulfates from the charred material, is not shown in the process flow diagram (FIGS. 1 and 2 ). However, it may be necessary under certain circumstances, because some organic carryover may not be avoidable.
The filtrate (Stream 13 ) containing methanol, water and residual succinic acid was distilled to separate methanol from the aqueous media and 250 g of methanol (Stream 14 ) was collected and stored for recycling. The bottom product of the distillation (Stream 16 ), which is an aqueous solution containing residual succinic acid and some sulfates, was evaporated down to a 60 ml solution. The solution was evaporated down to 60 ml so that the solution, along with fresh succinic acid, will make a solution consisting of approximately 25-30% w/w ammonium succinate (Stream 3 ) upon neutralization. This preparation mimics the concentration of Streams 2 and 16 by evaporation to make Stream 3 in the case of the process envisioned for the production of succinic acid from diammonium succinate (FIG. 1 ). Similarly, the preparation mimics the concentration of Streams 2 and 16 by evaporation to make Stream 2 a in the case of the process envisioned for the production of succinic acid from disodium succinate (FIG. 2 ). In both cases, Stream 16 recycles residual succinic acid to maximize the yield.
EXAMPLE 9
Cycle II:
The concentrated Stream 16 from Cycle I was combined with 16.5 g of fresh succinic acid. The resulting slurry was neutralized with 28.5 ml of 58% w/w ammonium hydroxide.
The aqueous solution of ammonium succinate, with a pH of 7.00, was taken in a crystallizer and 17.8 g of recycled ammonium bisulfate (Stream 17 ) and 33.2 g of fresh ammonium bisulfate was added. The acidification resulted in a pH adjustment to 1.45 and the crystallization of succinic acid. The addition of ammonium bisulfate exceeded the theoretical requirement by approximately 10 g. One contributing factor may be the severe hygroscopicity of ammonium bisulfate. The additional weight may be due to the hydration of recycled and fresh ammonium bisulfate. During these experiments, no precautions were taken to avoid hydration of ammonium bisulfate. Also, the reduction of the pH of the succinic acid slurry exceeded the optimal value of 1.6. The pH value reached 1.45 requiring more ammonium bisulfate. This outcome was not intentional.
The resulting slurry (Stream 4 ) was filtered. The separated crystalline succinic acid (Stream 5 ) was dried overnight at 70° C. The dry weight was 19.4 g. Theoretically, 16.5 g was expected. This outcome indicated the presence of some carryover sulfates in the succinic acid stream.
The crystalline succinic acid (Stream 5 ) containing some sulfates was dissolved in 79 g of methanol (Stream 10 ) to separate the succinic acid from the sulfates that co-crystallized with succinic acid. The undissolved sulfates (Stream 8 ) were filtered, dried and stored for thermal cracking. The dry weight of the sulfates was 4 g. Therefore, the weight of the succinic acid dissolved in methanol was 15.4 g. This amount corresponds to a yield of 93.3% yield (Stream 7 ).
Two hundred eighty six grams of methanol (Stream 15 ) was added to the filtrate (Stream 11 ) containing ammonium sulfate and any residual succinic acid, ammonium bisulfate, and sulfuric acid in a crystallizer. The resulting slurry was filtered. The crystalline sulfates were dried overnight at 70° C. The dry weight was 47.5 g at a yield of 83.6%. Accounting for the 4 g of undissolved sulfates in Stream 8 , the yield increases to 90.7%. The theoretical yield was 94.9%. The discrepancy between the actual and the theoretical yield may be due to the addition of hydrated ammonium bisulfate that results in an overestimation for the sulfates present in the system.
The sulfates (Stream 12 ) containing mostly ammonium sulfate and some residual ammonium bisulfate and sulfuric acid were added to a thermal cracking unit maintained at 300° C. for 55 minutes. During the cracking process, the molten sulfates turned black in color, indicating the presence of charred organic material. The molten sulfates were cooled to room temperature. During cooling, 50 ml of water was added to dissolve the sulfates. The solution containing the charred material was filtered with a 0.2 micron filter. The charred material was discarded. The clear solution was evaporated down to about 40 ml to concentrate the sulfates. 198 g of methanol was added to the solution. The resulting sulfate slurry was filtered and then dried at 70° C., overnight. The dry weight of the sulfates was 25 g. The filtrate was distilled to separate methanol and 154 g of methanol was collected and stored for recycling.
The filtrate (Stream 13 ) containing methanol, water and residual succinic acid was distilled to separate methanol from the aqueous media and 250 g of methanol (Stream 14 ) was collected and stored for recycling. The bottom product of the distillation (Stream 16 ), which is an aqueous solution containing residual succinic acid and some sulfates was evaporated down to a 60 ml solution.
EXAMPLE 10
Cycle III:
The concentrated Stream 16 from Cycle II was combined with 17.7 g of fresh succinic acid. The resulting slurry was neutralized with 28.5 ml of 58% w/w ammonium hydroxide.
The aqueous solution of ammonium succinate was taken in a crystallizer and 25 g of recycled ammonium bisulfate (Stream 17 ) and 25.5 g of fresh ammonium bisulfate was added. The acidification resulted in a pH adjustment to 1.6 and the crystallization of succinic acid. As in Cycle II, the addition of ammonium bisulfate exceeded the theoretical requirement by approximately 10 g.
The resulting slurry (Stream 4 ) was filtered. The separated crystalline succinic acid (Stream 5 ) was dried overnight at 70° C. The dry weight was 24.5 g. Theoretically, 17.7 g was expected. This outcome indicated the presence of some carryover sulfates in the succinic acid stream. The crystalline succinic acid (Stream 5 ) containing some sulfates was dissolved in 79 g of methanol (Stream 10 ) to separate the succinic acid from the sulfates that co-crystallized with succinic acid. The undissolved sulfates (Stream 8 ) were filtered, dried and stored for thermal cracking. The dry weight of the sulfates was 7.7 g. Therefore, the weight of the succinic acid dissolved in methanol was 16.8 g. This amount corresponds to a yield of 94.9% yield (Stream 7 ).
Two hundred seventy six grams of methanol (Stream 15 ) was added to the filtrate (Stream 11 ) containing ammonium sulfate and any residual succinic acid, ammonium bisulfate and sulfuric acid in a crystallizer. The resulting slurry was filtered. The crystalline sulfates were dried overnight at 70° C. The dry weight was 46.7 g at a yield of 83%. Accounting for the 7.7 g of undissolved sulfates in Stream 8 , the yield increases to 96.7%. The theoretical yield was 94.9%.
The sulfates (Stream 12 ) containing mostly ammonium sulfate and some residual ammonium bisulfate, and sulfuric acid were added to a thermal cracking unit maintained at 300° C. for 50 minutes. During the cracking process, the molten sulfates turned black in color indicating the presence of charred organic material. The molten sulfates were cooled to room temperature. During cooling, 50 ml of water was added to dissolve the sulfates. The solution containing the charred material was filtered with a 0.2 micron filter. The charred material was discarded. The clear solution was evaporated down to about 45 ml slurry to concentrate the sulfates. Added 237 g of methanol to the slurry. The resulting sulfate slurry was filtered and then dried at 70° C., overnight. The dry weight of the sulfates was 28.3 g. The filtrate was distilled to separate methanol and 225 g of methanol was collected and stored for recycling.
The filtrate (Stream 13 ) containing methanol, water and residual succinic acid was vacuum distilled to separate methanol from the aqueous media and 190 g of methanol (Stream 14 ) was collected and stored for recycling. The 37 ml bottom product of the vacuum distillation (Stream 16 ), which is an aqueous solution containing residual succinic acid and some sulfates was topped to a 60 ml solution with water.
EXAMPLE 11
Glucose from corn derived carbohydrates was anaerobically fermented with a microorganism (ATCC Accession No. 29305, American Type Culture Collection, 12301 Parklawn Drive, Rockville, MD 20852). Ammonia, as a neutralizing base, is added to the fermenter to neutralize succinic acid produced by the microbe into diammonium succinate. Output from the fermenter is a dilute (6-10% w/w) aqueous diammonium succinate solution, containing impurities. The stream is filtered to remove insolubles and was concentrated in a multi-effect evaporator to about 30% w/w. The concentrated solution with the pH of about 7 is fed into a succinic acid crystallizer, to which ammonium bisulfate is added to reduce the pH to between 1 and 2. Sulfuric acid can also be added at this point. The amount of ammonium bisulfate and/or sulfuric acid is determined by monitoring the solutions pH.
Crystallized succinic acid is filtered out to yield approximately 90% succinic acid on a weight basis. The filtrate containing ammonium sulfate, ammonium bisulfate and sulfuric acid is fed to a thermal cracking unit at approximately 300° C. Output from the thermal cracker is ammonia and ammonium bisulfate. The ammonium bisulfate and residual sulfuric acid are recycled back to the succinic acid crystallizer. Ammonia is fed from the thermal cracking unit to the fermenter.
EXAMPLE 12
Glucose is fermented with an organism producing succinic acid. Sodium bicarbonate is used as a neutralizing base to maintain a pH of approximately 7. The output is a 6-10% w/w aqueous disodium succinate solution. The stream is filtered and then concentrated to near saturation (50% w/w). This concentrate solution, having a pH of about 7.0 is fed into a crystallizer, to which ammonia (preferably recycled ammonia) and carbon dioxide are added. This converts the disodium succinate into diammonium succinate, with the formation of solid sodium bicarbonate. The bicarbonate can be recycled back into the fermenter as the neutralizing base.
The diammonium succinate is then fed to a succinic acid crystallizer, to which ammonium bisulfate is added, to reduce the pH to a range of about 1.0 to 2.4. Sulfuric acid can also be added at this point to lower the pH. This process yields approximately 90% succinic acid on a weight basis. The filtrate, resulting from the filtration of the succinic acid slurry, containing a mixture of ammonium sulfate and ammonium bisulfate and sulfuric acid is fed to a thermal cracking unit at about 300° C.
The method of the invention involves providing a solution with a succinate salt, concentrating the solution advantageously to near saturation, acidifying the solution to a pH between about 1.0 and 2.5 in the presence of sulfate ions, such as through the addition of ammonium bisulfate or sulfuric acid to yield crystallized succinic acid. The difference in solubility between sulfates and succinic acid in alcohol such as methanol can be used to further purify and separate succinic acid from the product streams. If metal salts, such as disodium succinate, the material can be combined with ammonia and carbon dioxide at a neutral pH to precipitate sodium bicarbonate, which can be recycled for use in raising the pH of the fermentation broth.
As discussed above, a cracking step can be employed, wherein the filtrate waste from the acidification step contains ammonium sulfate, ammonium bisulfate and sulfuric acid. The filtrate waste is fed into a thermal cracking unit, operating in the range of about 290 to 310° C., to produce ammonia and ammonium bisulfate, which can be recycled for use in earlier process steps.
A sulfate crystallizing step can be added after the acidifying step, wherein methanol is added to the slurry, causing crystallization of sulfates and dissolving the crystal in succinic acid, to form a methanol/succinic acid solution. Sulfate solids can be filtered out and cracked at about 300° C. The succinic acid can be crystallized from the methanol solution through evaporation. The evaporated methanol can be condensed and recycled for further use.
It can thus be seen that the present invention provides a process for converting either succinate salts, such as metal succinates or diammonium succinate into succinic acid and the step for further purifying the succinic acid involving alcohol dissolutions in preferably methanol.
It will thus be seen that the objects set forth above, among those made apparent form the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method and in the composition set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
Particularly it is to be understood that in said claims, ingredients or compounds recited in the singular are intended to include compatible mixtures of such ingredients wherever the sense permits. | A highly efficient process for the production and recovery of pure succinic acid from a succinate salt that involves minimal use of additional reagents, and produces virtually no waste by-products, and permits internal recycle of the base and acid values, is provided. The method involves the formation of diammonium succinate, either by using an ammonium ion based material to maintain neutral8 pH in the fermenter or by substituting the ammonium cation for the cation of the succinate salt created in the fermenter. The diammonium succinate can then be reacted with a sulfate ion, such as by combining the diammonium succinate with ammonium bisulfate and/or sulfuric acid at sufficiently low pH to yield succinic acid and ammonium sulfate. The ammonium sulfate is advantageously cracked thermally into ammonia and ammonium bisulfate. The succinic acid can be purified with a methanol dissolution step. Various filtration, reflux and reutilization steps can also be employed. |
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application relates to and claims priority of U.S. provisional patent application (“Copending Provisional Application”), Ser. No. 62/296,994, filed on Feb. 18, 2016. The disclosure of the Copending Provisional Application is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to integrated circuit counters, and more specifically to a method of operating the integrated circuit counter so that power consumption is minimized for use in low-power applications.
BACKGROUND OF THE INVENTION
[0003] Special industrial applications targeted to remote locations or highly-distributed system architectures (“Smart Dust” sensors, for example) call for the operation of electronic systems that are to be powered by energy harvested from the environment, without the need for a local battery or wired energy source. Since the amount of energy that can be derived from vibrations (or other mechanical motion) of the apparatus, light impinging on it, or electromagnetic field in its vicinity is extremely small, these systems are required to be designed for extreme energy efficiency—in both their analog and digital components.
[0004] One such electronic device that is most commonly needed in sensors is a simple event counter. By way of example, water or electrical utility meters rely on physical phenomena capable of translating the flow of the physical entity to be metered into a quantized electrical pulse, which can then be counted to quantify the consumption. Vibration sensors, such as strain gauges, can exploit piezoelectric properties of materials to produce pulses that, once counted, provide information as to the frequency and pattern of the motion under observation. The same principle can be applied to sensors, such as rotational encoders and distributed sensing for haptics solutions.
SUMMARY OF THE INVENTION
[0005] In order to conserve as much energy as possible and meet the tight power budgets of such “cycle counting” applications, the present invention discloses a segmented Thermometer Count Architecture (TCA) that reaches the thermodynamic energy minimum for an operation of this kind, requiring only one write or one erase operation per pulse. In fact, since the “bit” (Binary digIT) is the minimum amount of recordable information, a counting scheme that updates one single bit per event is to be considered energetically optimal by definition.
[0006] According to the present invention, a method of operating an integrated circuit comprising a plurality of digital registers of various respective lengths is disclosed, the method comprising performing only a single-bit write or single-bit erase operation in a single operational cycle to determine a bi-directional (increase or decrease) thermometer count. The integrated circuit can comprise a non-volatile memory integrated circuit such as a floating-gate non-volatile memory integrated circuit (Flash NVRAM). A first register in the integrated circuit counter is sized such that the endurance requirement on its corresponding memory cells upon a predetermined maximum event count is no greater than a predetermined floating-gate technology reliability limit. The method of operation of the present invention first comprises forward counting by performing successive single-bit write operations in a first register, up to the respective length of the first register. The forward counting method is subsequently continued by performing successive single-bit erase operations, after the single-bit write operations have reached the respective length of the first register. The forward counting method is also continued by performing successive single-bit write operations in a second register upon the single-bit write operations reaching the respective length of the first register. The forward counting method is continued in successive registers until a maximum count limit is reached. The integrated circuit counter of the present invention reaches a count limit when a last register contains all “logic one” values. Each register in the integrated circuit counter of the present invention comprises a highest value end bit and a lowest value end bit. The relative values of the highest value end bit and the lowest value end bit are indicative of a forward or reverse cycle. Identical values of the highest value end bit and lowest value end bit require reading additional registers to determine a forward or reverse cycle. Reverse counting is easily accomplished by sequentially reversing the forward counting write and erase operations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 shows a thermometer counter architecture according to the present invention wherein three registers of an integrated circuit are shown for monotonic counts 0 - 27 of a thermometer code that show forward counting in first and second registers;
[0008] FIG. 2 shows a thermometer counter architecture according to the present invention wherein three registers of an integrated circuit are shown for monotonic counts 83 - 11 of a thermometer code that show forward counting in all three registers;
[0009] FIG. 3 shows a thermometer counter architecture according to the present invention wherein three registers of an integrated circuit are shown for bi-directional counts 113 - 119 followed by 118 - 104 of a thermometer code that show forward and reverse counting in all three registers;
[0010] FIG. 4 shows a block diagram of a hardware embodiment of the integrated circuit counter according to the present invention;
[0011] FIG. 5 shows a flow chart of a counting method associated with the integrated circuit counter according to the present invention; and
[0012] FIGS. 6-10 show a count progression from a zero value count to a maximum value count associated with the integrated circuit counter according the present invention.
DETAILED DESCRIPTION
[0013] The implementation of the architecture in an integrated circuit counter according to the present invention is now described.
[0014] In a practical integrated circuit implementation, the thermometer code according to the present invention requires a plurality of n digital registers of respective lengths M 1 , M 2 . . . Mn. In a harvested-energy operated paradigm, for instance, the registers can be realized as part of a non-volatile memory block. FIG. 1 illustrates how the coding scheme works for a simple case of three registers 102 , 104 , and 106 where the respective lengths are given as M 1 =6, M 2 =5, and M 3 =3. Note in FIG. 1 that the corresponding thermometer code 108 is also shown, wherein counts 0-27 are shown occurring in time with each count cycle. Per each count cycle, the registers are updated according to the procedure set forth in the present invention and starting from the bottom of registers M 1 , M 2 , and M 3 in their respective sequence.
[0015] FIG. 2 shows the same three registers and thermometer code as was shown in FIG. 1 . These elements, however, are respectively labeled 202 , 204 , 206 , and 208 since they are shown at a later count range of 83-111. FIG. 2 also shows the thermometer code operation of the highest-weighted register 206 , which is invoked for higher value counts. As can be seen, a single cycle never requires more than a single write or a single erase operation, thus minimizing the energy required per cycle.
[0016] FIG. 3 shows the same three registers shown in FIG. 1 and FIG. 2 . These elements however, are respectively labeled 302 , 304 , 306 , and 308 since they are shown at a count increase range of 113-119 followed by a count decrease range of 118-104. As an additional desirable feature of this method, counting backwards upon a reverse count detection from the sensor under monitoring is easily accomplished by sequentially reversing all the operations, as shown in FIG. 3 .
[0017] It is important to note that, while in principle the same degree of thermodynamic efficiency could be reached by way of a straightforward thermometer count in a linear register, the integrated circuit register arrangement and digital update counting method of the present invention naturally limit the size of the register used, while still allowing for a very high event count. It can be easily shown that the maximum number of cycles C max that can be achieved with the disclosed Thermometer Count Architecture of the present invention is greater than the product of all the n register depths M i as follows:
[0000] C max >Π i=1 n M i (1)
[0000] Additional technological constraints may dictate the optimal sizing of the registers in the various applications, such as the register cell's endurance and reliability stress limits in the case of storage of the counts between successive occurrences of the energy-harvesting events in a non-volatile device. Since the “M 1 ” base register receives the highest number of read/write cycles, under these constraints it would need to be sized such that the endurance requirement on its cells be no greater than the particular floating-gate technology reliability limit. FIGS. 1-3 show that, unlike for a binary code where the Least Significant Bit (LSB) is continuously toggled and therefore its reliability stressed the most, the endurance requirement is essentially the same for each bit in the “M 1 ” register according to the teachings of this invention, which equalizes the reliability stress amongst all cells.
[0018] As an example, for an IC that must be able to count up to 2 32 (i.e. 4.3 billion events), the following combination will be sufficient to provide actually more than 4.3 billion cycles: M 1 =2 13 =8,192; M 2 =2,048; and M 3 =2 8 =256. The additional factor of 2 due to the double revolving of “1's” and “0's” before the next register (M 2 ) is updated, and the sequence on register M 1 repeats itself, is already factored in by the counting method as applied to the higher level registers. Even though the sum of the exponents 13+11+8 equals 32—i.e., the register sizing would be theoretically be the minimum necessary—thanks to the higher efficiency provided by the disclosed Thermometer Count Architecture this particular combination provides, in fact, as many as 4.299.687.167 cycles—compared to the requirement of 2 32 =4,294,967,296 cycles. The technique therefore delivers a full 4,719,871 extra cycles above the required maximum, due to its additional next-order bit set/reset mechanism, that adds more states as compared to a straight segmented thermometer count. The ASIC will have reached its limit when the last “M 3 ” register contains all “1” values; notice, however, that all the lower-order registers have been completely written and completely erased, and are ready in their native “all 0's” state upon reaching that final condition (as noticed in FIG. 10 ).
[0019] Practical electrical implementation aspects of the counting method and integrated circuit counter architecture of the present invention are now described. While the physical realization of the apparatus is conducive to using registers defined on a non-volatile memory, as addressed and modified by a simple state machine built with custom “glue logic” for maximum energy efficiency, it is important to recognize how alternative implementations such as Field-Programmable Gate Arrays (FPGA's) with internal memory banks can also be viable. As anticipated the invention not only minimizes the energy per count recorded, but also aims at optimizing the endurance characteristics of the memory registers or cells, ensuring the longest possible reliable operating life of electronic circuit embodiments.
[0020] One of the advantages of the Thermometer Count Architecture of the present invention is that the thermometer code need not be decoded to determine what is the next required write/erase operation. The revolving nature of each of the registers (especially the lowest-order “M 1 ” base register) only requires knowledge of the two end bits, to resolve which direction is required for a forward or reverse cycle. For example, referring to thermometer code “ 4 ” in FIG. 1 : by reading the lowest bit value of “1” and the highest bit value of “0” in the “M 1 ” register, the state machine knows that a “1” needs written at the interface between the “1's” and “0's” for the next forward cycle (program operation); or a “0” needs written at that same interface for the next reverse cycle (erase operation). In the case where both end bits in the “M 1 ” register have instead the same value (either both “1's” or both “0's”), the “M 2 ” and “M 3 ” registers must be read to determine the next step in the method—as in the case of thermometer code “ 7 ” in FIG. 1 . In this latter case, because of the sizes chosen for M 2 (5 bits) and M 3 (3 bits), since the value of the “M 2 +M 3 ” registers is odd the next operation is uniquely determined to be:
[0021] a. an erase in the “M 1 ” register, for a forward cycle; or
[0022] b. an erase in the “M 2 ” register, for a reverse cycle.
[0023] From an electrical point of view, having determined the nature (direction) of the next operation, the IC digital engine must now localize the interface between “1's” and “0's” in the register, to locate the next bit that needs to be modified. While this is a pure detail of practical electrical implementation, such a search becomes most critical for the “M 1 ” register if, e.g., tight endurance limitations are imposed on the memory registers by the reliability constraints of its technological implementation. Non-volatile memory circuits such as dual-gate tunneling Flash memory or other Electrically Erasable/Programmable Read-Only Memory (EEPROM) for instance will be subject to such endurance limitations. After having read the two end bits and determined that they are not identical, a binary search is performed. Using the example of thermometer code “ 4 ” in FIG. 1 : after reading the two end bits (and once determined that a forward count requires to write the next bit in the “upwards” direction, as shown in the figure), one or both of the two middle bits of the register can be read, to resolve that the next search should continue in the “upper” half of the register. This binary search method can then be efficiently iterated. Also, after some pre-determined number of binary search steps narrowing down on the location of the 0-1 interface, the best energy efficiency can be achieved by finishing with a sequential read—to be performed in the pre-determined direction to find the interface location between “0's” and “1's”. For example, after four such binary search steps in a 4,096-cell register (2 12 ), the maximum distance to the interface will be <256 (or 2 12 /2 4 ): now small enough, for example, for precharged dynamic digital arithmetic (“Manchester” logic chains) to be used effectively.
[0024] A block diagram 400 of a hardware embodiment of the integrated circuit of the present invention is shown in FIG. 4 . The counting method of the present invention can be realized in FSM 404 (Finite State Machine), which in turn can be implemented via a full μC (microcontroller), FPGA (Field-Programmable Gate Array), PLA (Programmable Logic Array), or even a custom CPU digital logic ASIC (Central Processing Unit coded in RTL/VHDL/Verilog and auto-placed and routed as an Application-Specific Integrated Circuit chip). Additional supporting circuitry can include a wake-up circuit 402 , a power management circuit 406 , non-volatile memory 408 , energy harvesting circuit 410 , charge pump 412 , clock circuit 414 , and event sensor 416 coupled together as shown. The counting method of the present invention can be implemented as 1) micro-programmed logic (maintaining program/data separation and a program counter, or merging program and data as in normal Von Neumann's architectures); but for maximal energy efficiency, 2) a more basic sequencer with a time counter generating a sequential series of decoded signals to operate the various comparators, adders and Program/Erase memory drive lines, which can be synthesized following a number of coding styles from RTL, to Verilog.
[0025] The Thermometer-to-Binary decoding according to the present invention is now described.
[0026] For practical purposes a decoding method of the Thermometer Count Architecture code format into the more customary binary representation is now described. Supposing the locations of the “0's” to “1's” interfaces within the three thermometer registers in the example (M 1 , M 2 , and M 3 ) are i, j, and k respectively, it can be shown that the integer count, D, for the total number of cycles recorded is given by the following equations:
[0000] D=k ·( M 1+1)·( M 2+1)+( k % 2) ·B +[( k+ 1) ·A (2a)
[0000] B =(M1+1)·( M 2+1)−1 −A (2b)
[0000] A=j +( j·M 1)+( M 1 −i )·( j % 2)+( i ·[( j+ 1) % 2]) (2c)
[0000] where the symbol “% ” represents the remainder of a modulus (integer ratio) operation. Essentially j % 2 returns 0 for even j and 1 for odd j, which is implemented in practice via a simple one-bit counter or a single flip-flop as an input frequency divider. Note that the values (M 1 +1), (M 2 +1), and their product (M 1 +1)·(M 2 +1) are design parameters that can be hard-coded into the decoder; and a convenient choice of the registers' size enables the binary multiplications to be converted into efficient bit-shifts (e.g., M 1 =7 and M 2 =3 would turn (M 1 +1)·(M 2 +1) into a simple 5-bit left shift). Also, the factors multiplied by the remainder of the modulus-2 operation can take on only two possible values: the original value, or zero. A true integer multiplication is therefore not required; all that is required in this case is a comparison of the LSB of the respective binary counter to the one-bit counter implementing the “% 2” function. In conclusion there are only two true integer multiplications required in the decoding: k·C, where C=(M 1 +1)·(M 2 +1); and j·M 1 .
[0027] Error Detection and Correction and “Bubbles” are now described.
[0028] By its very nature, a thermometer code contains some redundancy. The only real information is contained in the location of the interface between “1's” and “0's”. Yet, except for the cases where the thermometer code is close to the upper or lower register boundary, there are multiple programmed hits that concur in defining the location of the boundary. Therefore, one may be able to tolerate mis-reads or flipped bits, provided those errors (typically referred to as “bubbles” in digital jargon) do not interfere with the effective location of the interface. As stated, the last phase of finding the bit code “0-1” interface may involve sequential reads of the register cells, in order to make the search more robust. In the example used above (thermometer code “ 4 ” in FIG. 1 ), if the reading starts in the portion of the register containing all “1's” and stops upon reading the first an error might occur if this first “0” happens to he a “bubble” occurrence. A more robust procedure would, however, read two bits beyond the interface. In this way, the probability of incorrectly determining the interface coincides with the probability of having two consecutive bubble errors, which is the joint probability of two rare events, hence presumably extremely small. If a bubble is detected, independent of its nature (“0” or “1”), it can be flagged and scheduled for correction at the end of all other normal operations, depending on the energy supply regimen requested of the IC. If the bubble is sufficiently “deep” inside the thermometer code (i.e. away from the “0-1” interface), there will be multiple chances for it to be re-written or re-erased; if it happens at the interface though, it may cause an error in the count. Indeed, notice that the counting method of the present invention will inherently attempt to correct the bubble for all consecutive instances of the count, until the cell has been successfully over-written.
[0029] Standard bubble-correction circuits utilizing banks of NAND gates with conveniently inverted inputs can be usefully designed in a dedicated ASIC for maximal energy efficiency, or also instantiated into a flexible FPGA configuration.
[0030] As a variant of the normal counting method as it has been outlined above, should the bit not be successfully read after being re-written, it may be replaced by diverting the address for that bit to a limited number of “spare bits”. This technique would be in line to what is currently common practice for EEPROM and Flash memory architectures (i.e. “paging”).
[0031] The energy budget of a basic, full-custom CMOS integrated circuit implementation of the present invention is finally described.
[0032] An estimate of the energy required to operate the Thermometric Count Architecture counting method of the present invention in a commercial 0.35 μm CMOS ASIC, clocked with a 5 MHz square wave, with registers sized as previously described for a 4-billion count total, is outlined in the following table:
[0000] TABLE I IC operation Energy Unit Comments Longest Seek Operation 1.0 nJ 520 reads @ 5 MHz Erase (max. energy) 135.0 nJ Requires 0.5 ms @ 5 MHz Margin Read 0.1 nJ Actually <0.1 nJ Shut Down Tasks 0.1 nJ Digital logic RESET TOTAL 136.2 nJ
The energy values as reported refer to a fully custom design of the digital logic. More flexible digital implementations of the TCA method such as FPGAs or PLAs forcibly would not be as energy efficient, due to node multiplexing options inherent to these architectures and therefore to the corresponding increase of the parasitics affecting the same nodes.
[0033] Referring now to FIG. 5 , a flow chart 500 shows the operation of the various components associated with the integrated circuit counter of the present invention in case of an “increase” event count. The M 1 , M 2 , and M 3 register designations previously defined are used in flow chart 500 . The counting method starts at step 502 . An “increase” data event occurs at step 504 . At decision point 506 , the integrated circuit counter of the present invention determines whether M 1 is not equal to (0,6), which means checking whether the top value and bottom value of the M 1 register are not equal. If yes, the counting method proceeds to step 508 , which shifts the M 1 interface by one. If no, the counting method proceeds to decision point 512 , which determines whether the value of register M 1 is equal to 6. If yes, the counting method proceeds to decision point 510 . If no, the counting method proceeds to decision point 516 . Decision point 510 determines whether the sum of M 2 and M 3 is odd. Decision point 516 also determines whether the sum of M 2 and M 3 is odd (or whether the top and bottom values of the sum are equal to zero). Regarding decision point 510 , if yes, the counting method proceeds back to step 508 . If no, the counting method proceeds to step 522 . Regarding decision point 516 , if yes, the counting method proceeds to decision point 518 . Method step 522 shifts the interface of register M 2 by one. Decision point 518 determines whether the value of register M 2 is not equal to (0,5). If not, the counting method proceeds to decision point 520 . If yes, the counting method again proceeds to step 522 . Decision point 520 determines whether the value of register M 3 is not equal to 3. If not, then all registers have been filled and the counting method terminates at step 528 . If yes, then the counting method proceeds to step 524 . Step 524 shifts the interface of register M 3 by one. Regarding steps 508 , 522 and 524 , the counting method proceeds to “wait for next event” step 526 . Once a next data event (increase or decrease) occurs, the counting method proceeds back to step 504 . While a representative flow chart 500 is shown in FIG. 5 for operating the integrated circuit counter according to the present invention in an “increase” event, it is known to those skilled in the art that other logical equivalents and even other possible flow charts could be constructed, for both “increase” and “decrease” events.
[0034] The counting method according to the present invention is fully illustrated from a minimum count to a maximum count through “increase” events in FIGS. 6-10 . FIGS. 6-10 reconstruct the successive states assumed bv the three registers (M 1 , M 2 , and M 3 ) during a monotonically increasing event count, detailing all the mathematical terms as previously outlined in Equation (2) and showing the revolving population of “1” and “0” instantiated into registers M 1 , M 2 and M 3 in a hierarchical fashion, as controlled by the procedure previously described with respect to FIG. 5 . In FIGS. 6-10 , as previously described, “i” is the value of M 1 , “j” is the value of M 2 , “k” is the value of M 3 —a “1” count in the registers themselves; and “A” and and “count” were all previously described. Various significant count transitions with respect to “i”, “j”, and “k” are also illustrated in FIGS. 6-10 . It is important to note when inspecting FIGS. 6-10 that all of the numbers and graphical items are to be read vertically. For example, a representative count 802 is shown in FIG. 8 . In FIG. 8 it will be understood by those skilled in the art that i=6, j=0, k=2, A=6, B=35, and count=90. As another example, a representative count 1002 is shown in FIG. 10 . In FIG. 10 it will be understood that i=6, j=2, k=3, A=20, B=21, and count=147.
[0035] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent hardware, firmware, and software implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof. | An integrated circuit counter includes a segmented thermometer coding counter architecture that reaches the thermodynamic energy minimum for a forward/reverse counting operation, requiring only one write or one erase operation per count so that energy consumption can be minimized, and circuit endurance maximized. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to an improved grapple boom configuration for a skidder and in particular a grapple boom configuration that is adaptable for multiple usages without disassembly and specifically, a grapple boom configuration which allows the skidder to be used as a grapple skidder, and, when the grapple is pinned to the upper end of the boom out of the way of the winch and cable, as a cable skidder.
2. History of the Prior Art
Typically, a skidder vehicle is designed for operation in two modes. As a cable skidder, the vehicle plays out a length of cable from a winch attached to a skidder boom. A number of shorter choker cables attached to the outer end of the cable may, in turn, be secured to individual logs. A plurality of logs may then be dragged up a slope or out of the woods into a cleared area by activating the winch to draw up the cable. After a number of logs have been gathered into piles of three to six logs each, the cable skidder can then be converted to a grapple skidder wherein a grapple mechanism is mounted on the boom in pivotable engagement therewith for gathering individual groups of logs to a central location.
In the typical example of the prior art, once the logs are gathered by the grapple skidder, the grapple mechanism must again be detached from the boom so that the skidder vehicle may again operate as a cable skidder. In some cases the cable skidding boom and the grapple skidding boom are different and in other cases the same boom is used in both the cable skidding and the grapple skidding mode of operation but a separate grapple mechanism must be attached to the boom before the skidder vehicle can operate as a grapple skidder. The present invention offers an improved grapple boom configuration which permits the grapple to be rotated out of the way when it is desired that the skidder vehicle be operated as a cable skidder. The grapple is retained in an out-of-the-way position by engaging the grapple arms above and atop the boom arms and securing the upper end of the grapple and the upper end of the boom in pinned relationship.
SUMMARY OF THE INVENTION
The improved grapple boom assembly comprises a base support structure having a pair of columns which converge upwardly in an A-frame configuration. The bottom of each column is pinned to the rear of the skidder frame on opposite sides thereof and adjacent respective fenders at the inner walls thereof. A pair of horizontally extending hydraulic cylinders are connected to respective mid-portions of the columns for raising and lowering the boom. The boom columns converge upwardly and curve rearwardly to form the A-frame configuration which has mounted at its upper end a rearwardly extending grapple support member which is generally perpendicular to the boom columns and carries thereon pivotal mounting means for the grapple mechanism. The grapple mechanism is pivotally mounted on the grapple support member and may be pivotally rotated about respective horizontal and vertical axes of rotation. When the grapple mechanism is pivotally rotated about its horizontal axis of rotation toward the grapple boom, mating brackets on the grapple mechanism and on the grapple support member become aligned when the grapple mechanism is finally rotated to a relatively parallel orientation with respect to the grapple support member. Openings in respective brackets are then aligned so that a pin may be inserted therethrough to hold the grapple mechanism in fixed relationship with respect to the grapple boom, with the arms of the grapple mechanism overlying the boom arms.
A built-in fairlead, comprising a main roller and two side rollers is disposed in the boom arch below the grapple mechanism so that the cable from the winch may be played out over the main roller without interfering with the pinned grapple mechanism when the vehicle operates as a cable skidder. To operate the vehicle as a grapple skidder, the cable is drawn up and the pin is released, permitting the grapple mechanism to freely pivot downward.
Although the present design configuration offers a simple method of transferring a boom configuration from a cable skidder mode to a grapple skidder mode easily and without removal of the grapple mechanism from the vehicle, substantial design modifications were required to achieve the desired result. The boom was designed to be sufficiently narrowed to accommodate the arms of the grapple mechanism thereabove when the vehicle is in the cable skidder mode, a suitable connection had to be provided between the boom and the grapple mechanism to retain the grapple mechanism in a suitable configuration for the cable skidder mode and the fairlead rollers had to be suitably mounted for compatible operation with the grapple in both the cable skidder and the grapple skidder modes of operation.
Thus, the present device, simple in its end result, required innovative engineering considerations and substantial modifications of existing designs to produce a grapple boom configuration which can be easily transferred from a grapple skidder mode of operation to a cable skidder mode of operation without connecting and disconnecting the grapple mechanism and the boom whenever the mode of operation is changed. These and other advantages will become more apparent when the following detailed description of the invention is considered with the drawings which are described below as follows.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a rear perspective view of a skidder vehicle with a grapple boom assembly mounted thereon in the grapple skidder mode;
FIG. 2 is a rear perspective view of the grapple boom assembly of the present invention with the grapple mechanism partially rotated to a cable skidder mode;
FIG. 3 is a detail view showing the grapple boom connection when the grapple mechanism is pivoted to the cable skidder mode; and
FIG. 4 is a rear perspective view of the skidder vehicle with the grapple boom assembly thereof having the grapple mechanism mounted in the cable skidder mode.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a rear perspective view of a grapple boom assembly 10 including a skidder boom 12 comprising a pair of columnar members 14, each pivotally mounted at the rear of the skidder frame 15 adjacent respective opposite skidder side frame skirts or fenders 16 at a lower pivotal mounting location 18. Boom support columns 14 extend upwardly and curve rearwardly from opposite sides of the skidder frame to converge into an A-frame configuration which extends rearwardly of the skidder frame 15 at its upper end and terminates in a grapple support member 32 which is relatively perpendicular to the skidder boom 12. Respective hydraulic cylinders 20 each pinned at one end to each boom support column 14 at location 22 and at the other end to the frame 15 rotate the grapple boom assembly 10 to permit a grapple mechanism 24 to engage piles of logs laying on the ground. The grapple mechanism 24 has opposing grapple arms 26 each controlled by respective hydraulic cylinders or snubbers 28 appropriately connected thereto. The grapple mechanism 24 is connected to the grapple support member 32 by a grapple pivot connection 30, which may be similar to the one described in U.S. Pat. No. 3,990,688 entitled "Grapple Skidder with Self-Centering Grapple Support Mechanism" issued Nov. 9, 1976 and assigned to the assignee of the present invention. The grapple pivot connection 30 permits the grapple mechanism 24 to pivot about respective horizontal and vertical axes.
As shown in FIG. 2, the unique configuration of the skidder boom 12 coordinated with its grapple support member 32 permits the grapple mechanism 24 to be rotated upwardly as follows. A cable 34 extending from winch 36 may be connected to a metal loop 38 provided on the grapple mechanism 24. Hydraulic cylinders 28 may be retracted to spread the grapple arms 26 apart and the winch 36 activated to draw the grapple mechanism 24 up toward the boom structure 12.
As shown in FIG. 3, as the grapple mechanism 24 is drawn up toward the boom 12, an extension plate or member 42 mounted on the grapple mechanism 24 engages a slot 43 in a clevis 44 mounted on the grapple support member 32. The grapple mechanism 24, when fully rotated, aligns respective openings 46 and 48 in the bracket 42 and the clevis 44 to receive a pin 50 which then holds the skidder boom 12 and the grapple mechanism 24 in the cable skidder mode of operation. Grapple cylinders 28 may then be extended to close the grapple arms 26 above the boom support columns 14 as shown in FIG. 4. The grapple boom assembly 10 comprises a built-in fairlead assembly 51 which includes a main cable roller 52 and a pair of side cable rollers 53 associated with the winch 36 and so mounted on the skidder boom 12 that they extend below the grapple assembly 10 when the grapple mechanism 24 is mounted in the cable skidder mode of operation enabling the cable 34 to play out below the grapple mechanism 24 and over the main horizontal roller guide 52 to easily enable the skidder vehicle to operate in a cable skidder mode without removal of the grapple mechanism 24.
Thus, the present invention offers a simple method of converting a skidder vehicle from a cable skidder mode to a grapple skidder mode without interchanging skidding booms and grapple booms or removing the grapple assembly from the skidder boom when a cable skidder mode of operation is desirable. This unique labor-saving feature has been effected by the innovative design of the present grapple boom configuration.
While the above detailed description sets forth a preferred embodiment of our invention, it should be understood that such description is for the purposes of illustration only and that various modifications and changes may be made in the above-described device without departing from the nature and the scope of the invention as set forth in the appended claims. | An improved boom grapple assembly which enables a skidder operator to easily transform the boom grapple assembly from a grapple skidder mode of operation to a cable skidder mode of operation and back again. |
This application is a continuation of application Ser. No. 08/135,841, filed Oct. 7, 1993, which is a continuation of U.S. application Ser. No. 07/840,149, filed Feb. 24, 1992, now abandoned, which is a divisional of U.S. application Ser. No. 07/393,749, filed on Aug. 15, 1989, now U.S. Pat. No. 5,091,171, which is a continuation-in-part of U.S. application Ser. No. 06/945,680, filed on Dec. 23, 1986, now abandoned.
FIELD OF THE INVENTION
This invention relates generally to therapeutic treatment as well as preventive measures for cosmetic conditions and dermatologic disorders by topical administration of amphoteric compositions or polymeric forms of alpha hydroxyacids, alpha ketoacids and related compounds. We initially discovered that alpha hydroxy or keto acids and their derivatives were effective in the topical treatment of disease conditions such as dry skin, ichthyosis, eczema, palmar and plantar hyperkeratoses, dandruff, acne and warts.
We have now discovered that amphoteric compositions and polymeric forms of alpha hydroxyacids, alpha ketoacids and related compounds on topical administration are therapeutically effective for various cosmetic conditions and dermatologic disorders.
BRIEF DESCRIPTION OF THE PRIOR ART
In our prior U.S. Pat. No. 3,879,537 entitled "Treatment of Ichthyosiform Dermatoses" we described and claimed the use of certain alpha hydroxyacids, alpha ketoacids and related compounds for topical treatment of fish-scale like ichthyotic conditions in humans. In our U.S. Pat. No. 3,920,835 entitled "Treatment of Disturbed Keratinization" we described and claimed the use of these alpha hydroxyacids, alpha ketoacids and their derivatives for topical treatment of dandruff, acne, and palmar and plantar hyperkeratosis.
In our prior U.S. Pat. No. 4,105,783 entitled "Treatment of Dry Skin" we described and claimed the use of alpha hydroxyacids, alpha ketoacids and their derivatives for topical treatment of dry Skin. In our recent U.S. Pat. No. 4,246,261 entitled "Additives Enhancing Topical Corticosteroid Action" we described and claimed that alpha hydroxyacids, alpha ketoacids and their derivatives, could greatly enhance the therapeutic efficacy of corticosteroids in topical treatment of psoriasis, eczema, seborrheic dermatitis and other inflammatory skin conditions.
In our more recent U.S. Pat. No. 4,363,815 entitled "Alpha Hydroxyacids, Alpha Ketoacids and Their Use in Treating Skin Conditions" we described and claimed that alpha hydroxyacids and alpha ketoacids related to or originating from amino acids, whether or not found in proteins, were effective in topical treatment of skin disorders associated with disturbed keratinization or inflammation. These skin disorders include dry skin, ichthyosis, palmar and plantar hyperkeratosis, dandruff, Darier's disease, lichen simplex chronicus, keratoses, ache, psoriasis, eczema, pruritus, warts and herpes.
In our most recent patent application Ser. No. 945,680 filed Dec. 23, 1986 and entitled "Additives Enhancing Topical Actions of Therapeutic Agents" we described and claimed that incorporation of an alpha hydroxyacid or related compound can substantially enhance therapeutic actions of cosmetic and pharmaceutical agents.
SUMMARY OF THE INVENTION
There is no doubt that alpha hydroxyacids, alpha ketoacids and related compounds are therapeutically effective for topical treatment of various cosmetic conditions and dermatologic disorders including dry skin, acne, dandruff, keratoses, age spots, wrinkles and disturbed keratinization. However, the compositions containing these acids may irritate human skin on repeated topical applications due to lower pH of the formulations. The irritation may range from a sensation of tingling, itching and burning to clinical signs of redness and peeling. Causes for such irritation may arise from the following:
Upper layers of normal skin have a pH of 4.2 to 5.6, but the compositions containing most alpha hydroxyacids or alpha ketoacids have pH values of less than 3.0. For example, a topical formulation containing 7.6% (1M) glycolic acid has a pH of 1.9, and a composition containing 9% (1M) lactic acid has the same pH of 1.9. These compositions of lower pH on repeated topical applications can cause a drastic pH decrease in the stratum corneum of human skin, and provoke disturbances in intercorneocyte bondings resulting in adverse skin reactions, especially to some individuals with sensitive skin.
Moreover, with today's state of the art it is still very difficult to formulate a lotion, cream or ointment emulsion which contains a free acid form of the alpha hydroxyacid, and which is physically stable as a commercial product for cosmetic or pharmaceutical use.
When a formulation containing an alpha hydroxyacid or alpha ketoacid is reacted equimolarly or equinormally with a metallic alkali such as sodium hydroxide or potassium hydroxide the composition becomes therapeutically ineffective. The reasons for such loss of therapeutic effects are believed to be as follows:
The intact skin of humans is a very effective barrier to many natural and synthetic substances. Cosmetic and pharmaceutical agents may be pharmacologically effective by oral or other systematic administration, but many of them are much less or totally ineffective on topical application to the skin. Topical effectiveness of a pharmaceutical agent depends on two major factors; (a) bioavailability of the active ingredient in the topical preparation and (b) percutaneous absorption, penetration and distribution of the active ingredient to the target site in the skin. For example, a topical preparation containing 5% salicylic acid is therapeutically effective as a keratolytic, but that containing 5% sodium salicylate is not an effective product. The reason for such difference is that salicylic acid is in bioavailable form and can penetrate the stratum corneum, but sodium salicylate is not in bioavailable form and cannot penetrate the stratum corneum of the skin.
In the case of alpha hydroxyacids, a topical preparation containing 5% glycolic acid is therapeutically effective for dry skin, but that containing 5% sodium glycollate is not effective. The same is true in case of 5% lactic acid versus 5% sodium lactate. The reason for such difference is that both glycolic acid and lactic acid are in bioavailable forms and can readily penetrate the stratum corneum, but sodium glycollate and sodium lactate are not in bioavailable forms and cannot penetrate the stratum corneum of the skin.
When a formulation containing an alpha hydroxyacid or alpha ketoacid is reacted equimolarly or equinormally with ammonium hydroxide or an organic base of smaller molecule the composition still shows some therapeutic effects for certain cosmetic conditions such as dry skin, but the composition has lost most of its potency for other dermatologic disorders such as wrinkles, keratoses, age spots and skin changes associated with aging.
It has now been discovered that amphoteric compositions containing alpha hydroxyacids, alpha ketoacids or related compounds, and also the compositions containing dimeric or polymeric forms of hydroxyacids overcome the aforementioned shortcomings and retain the therapeutic efficacies for cosmetic conditions and dermatologic disorders. The amphoteric composition contains in combination an amphoteric or pseudoamphoteric compound and at least one of the alpha hydroxyacids, alpha ketoacids or related compounds. Such amphoteric system has a suitable pH, and can release the active form of an alpha hydroxyacid or alpha ketoacid into the skin. The dimeric and polymeric forms of alpha, beta or other hydroxyacids in non-aqueous compositions have a more desired pH than that of the monomeric form of the hydroxyacids. The non-aqueous compositions can be formulated and induced to release the active form of hydroxyacids after the compositions have been topically applied to the skin. The cosmetic conditions and dermatologic disorders in humans and animals, in which the amphoteric compositions containing the dimeric or polymeric forms of hydroxyacids may be useful, include dry skin, dandruff, ache, keratoses, psoriasis, eczema, pruritus, age spots, lentigines, melasmas, wrinkles, warts, blemished skin, hyperpigmented skin, hyperkeratotic skin, inflammatory dermatoses, skin changes associated with aging and as skin cleansers.
DETAILED DESCRIPTION OF THE INVENTION
I. Amphoteric and Pseudoamphoteric Compositions
Amphoteric substances by definition should behave either as an acid or a base, and can be an organic or an inorganic compound. The molecule of an organic amphoteric compound should consist of at least one basic and one acidic group. The basic groups include, for example, amino, imino and guanido groups. The acidic groups include, for example, carboxylic, phosphoric and sulfonic groups. Some examples of organic amphoteric compounds are amino acids, peptides, polypeptides, proteins, creatine, aminoaldonic acids, aminouronic acids, lauryl aminopropylglycine, aminoaldaric acids, neuraminic acid, desulfated heparin, deacetylated hyaluronic acid, hyalobiuronic acid, chondrosine and deacetylated chondroitin.
Inorganic amphoteric compounds are certain metallic oxides such as aluminum oxide and zinc oxide.
Pseudoamphoteric compounds are either structurally related to true amphoteric compounds or capable of inducing the same function when they are incorporated into the compositions containing alpha hydroxyacids or ketoacids. Some examples of pseudoamphoteric compounds are creatinine, stearamidoethyl diethylamine, stearamidoethyl diethanolamine, stearamidopropyl dimethylamine, quaternary ammonium hydroxide and quaternium hydroxide.
The amphoteric composition of the instant invention contains in combination an alpha hydroxyacid or alpha ketoacid and an amphoteric or pseudoamphoteric compound. There are two advantages of utilizing an amphoteric or the like compound in the therapeutic composition containing an alpha hydroxy or ketoacid. These are (a) the overall pH of the composition is raised, so that the composition becomes less or non-irritating to the skin and (b) some alpha hydroxy or ketoacid molecules react with the amphoteric compound to form a quadruple ionic complex which acts as buffering system to control the release of alpha hydroxy or ketoacid into the skin, therefore, eliminating the skin irritation and still retaining the therapeutic efficacies.
The following are some examples. 2-Hydroxyethanoic acid (glycolic acid) 1M aqueous solution has pH 1.9. The pHs of compositions change to 3.0 and 3.2 when arginine 0.5M and creatinine 0.5M respectively are incorporated into the formulations. 2-Hydroxypropanoic acid (lactic acid) 1M aqueous solution has pH 1.9. The pHs of compositions change to 3.1 and 6.9 when arginine 0.5M and 1.0M respectively are incorporated into the formulations. 2-Methyl 2-hydroxypropanoic acid (methyllactic acid) 1M aqueous solution has pH 1.9. The pHs of compositions change to 3.3, 3.4 and 3.2 when 0.5M each of arginine, creatinine and 4-aminobutanoic acid respectively are incorporated into the formulations. 2-Hydroxybutane-1,4-dioic acid (malic acid) 1M aqueous solution has pH 1.8, but the pH of the composition changes to 3.0 when creatinine 0.5M is incorporated into the formulation.
Ideally, an amphoteric compound should contain both anionic and cationic groups or functional groups capable of behaving both as an acid and a base. Although inorganic amphoteric compounds such as aluminum oxide, aluminum hydroxide and zinc oxide may be utilized, organic amphoteric compounds have been found to be more efficient in formulating therapeutic compositions of the instant invention.
Organic amphoteric and pseudoamphoteric compounds may be classified into three groups, namely (a) amino acid type, (b) imidazoline and lecithin amphoterics and (c) pseudoamphoterics and miscellaneous amphoterics.
(a) Amino acid type amphoterics. Amphoteric compounds of amino acid type include all the amino acids, dipeptides, polypeptides, proteins and the like which contain at least one of the basic groups such as amino, imino, guanido, imidazolino and imidazolyl, and one of the acidic groups such as carboxylic, sulfonic, sulfinic and sulfate.
Glycine is a simple amphoteric compound which contains only one amino group and one carboxylic group. Lysine contains two amino groups and one carboxylic group. Aspartic acid contains one amino group and two carboxylic groups. Arginine contains one amino group, one guanido group and one carboxylic group. Histidine contains one amino group, one imidazolyl group and one carboxylic group. Taurine contains one amino group and one sulfonic group. Cysteine sulfinic acid contains one amino group, one carboxylic group and one sulfinic group. The amino group of an amphoteric compound may also be substituted, such as in betaine which is a glycine N,N,N-trimethyl inner salt.
Glycylglycine is a simple dipeptide which contains one free amino group and one free carboxylic group. Glycylhistidine is also a dipeptide which contains one free amino group, one imidazolyl group and one free carboxylic group.
The representative amphoteric compounds of amino acid type may be listed as follows: Glycine, alanine, valine, leucine, isoleucine, serine, threonine, cysteine, cystine, methionine, aspartic acid, asparagine, glutamic acid, glutamine, arginine, lysine, 5-hydroxylysine, histidine, phenylalanine, tyrosine, tryptophan, 3-hydroxyproline, 4-hydroxyproline and proline.
The related amino acids include homocysteine, homocystine, homoserine, ornithine, citrulline, creatine, 3-aminopropanoic acid, theanine, 2-aminobutanoic acid, 4-aminobutanoic acid, 2-amino-2-methylpropanoic acid, 2-methyl-3-aminopropanoic acid, 2,6-diaminopimelic acid, 2-amino-3-phenylbutanoic acid, phenylglycine, canavanine, canaline, 4-hydroxyarginine, 4-hydroxyornithine, homoarginine, 4-hydroxyhomoarginine, β-lysine, 2,4-diaminobutanoic acid, 2,3-diaminopropanoic acid, 2-methylserine, 3-phenylserine and betaine.
Sulfur-containing amino acids include taurine, cysteinesulfinic acid, methionine sulfoxide and methionine sulfone.
The halogen-containing amino acids include 3,5-diiodotyrosine, thyroxine and monoiodotyrosine. The imino type acids include pipecolic acid, 4-aminopipecolic acid and 4-methylproline.
The dipeptides include for example, glycylglycine, carnosine, anserine, ophidine, homocarnosine, β-alanyllysine, β-alanylarginine. The tripeptides include for example, glutathione, ophthalmic acid and norophthalmic acid. Short-chain polypeptides of animal, plant and bacterial origin containing up to 100 amino acid residues include bradykinin and glucagon. The preferred proteins include for example protamines, histones and other lysine and arginine rich proteins.
(b) Imidazoiine and lecithin amphoterics. The amphoteric compounds of imidazoline derived type are commercially synthesized from 2-substituted-2-imidazolines obtained by reacting a fatty acid with an aminoethylethanolamine. These amphoterics include cocoamphoglycine, cocoamphopropionate, and cocoamphopropylsulfonate. The amphoteric compounds of lecithin and related type include for example, phosphatidyl ethanolamine, phosphatidyl serine and sphingomyelin.
(c) Pseudoamphoterics and miscellaneous amphoterics. Many pseudoamphoteric compounds are chemically related or derived from true amphoterics. For example, creatinine is derived from creatine. Other pseudoamphoteric compounds may include fatty amide amines such as stearamidoethyl diethylamine, stearamidoethyl diethanolamine and stearamidopropyl dimethylamine. Other pseudoamphoteric related compounds include quaternary ammonium hydroxide and quaternium hydroxide.
In accordance with the present invention, the alpha hydroxyacid, the alpha ketoacids and the related compounds which are incorporated into amphoteric or pseudoamphoteric compositions for cosmetic conditions and dermatologic disorders may be classified into three groups.
The first group is organic carboxylic acids in which one hydroxyl group is attached to the alpha carbon of the acids. The generic structure of such alpha hydroxyacids may be represented as follows:
(Ra) (Rb) C (OH) COOH
where Ra and Rb are H, F, Cl, Br, alkyl, aralkyl or aryl group of saturated or unsaturated, isomeric or non-isomeric, straight or branched chain or cyclic form, having 1 to 25 carbon atoms, and in addition Ra and Rb may carry OH, CHO, COOH and alkoxy group having 1 to 9 carbon atoms. The alpha hydroxyacids may be present as a free acid or lactone form, or in a salt form with an organic base or an inorganic alkali. The alpha hydroxyacids may exist as stereoisomers as D, L, and DL forms when Ra and Rb are not identical.
Typical alkyl, aralkyl and aryl groups for Ra and Rb include methyl, ethyl, propyl, isopropyl, butyl, pentyl, octyl, lauryl, stearyl, benzyl and phenyl, etc. The alpha hydroxyacids of the first group may be divided into (1) alkyl alpha hydroxyacids, (2) aralkyl and aryl alpha hydroxyacids, (3) polyhydroxy alpha hydroxyacids, and (4) polycarboxylic alpha hydroxyacids. The following are representative alpha hydroxyacids in each subgroup.
(1) Alkyl Alpha Hydroxyacids
1. 2-Hydroxyethanoic acid (Glycolic acid, hydroxyacetic acid)
(H) (H) C (OH) COOH
2. 2-Hydroxypropanoic acid (Lactic acid) (CH 3 ) (H) C (OH) COOH
3. 2-Methyl 2-hydroxypropanoic acid (Methyllactic acid) (CH 3 ) (CH 3 ) C (OH) COOH
4. 2-Hydroxybutanoic acid (C 2 H 5 ) (H) C (OH) COOH
5. 2-Hydroxypentanoic acid (C 3 H 7 ) (H) C (OH) COOH
6. 2-Hydroxyhexanoic acid (C 4 H 9 ) (H) C (OH) COOH
7. 2-Hydroxyheptanoic acid (C 5 H 11 (H) C (OH) COOH
8. 2-Hydroxyoctanoic acid (C 6 H 13 ) (H) C (OH) COOH
9. 2-Hydroxynonanoic acid (C 7 H 15 ) (H) C (OH) COOH
10. 2-Hydroxydecanoic acid (C 8 H 17 ) (H) C (OH) COOH
11. 2-Hydroxyundecanoic acid (C 9 H 19 ) (H) C (OH) COOH
12. 2-Hydroxydodecanoic acid (Alpha hydroxylauric acid) (C 10 H 21 ) (H) C (OH) COOH
13. 2-Hydroxytetradecanoic acid (Alpha hydroxymyristic acid) (C 12 H 25 ) (H) C (OH) COOH
14. 2-Hydroxyhexadecanoic acid (Alpha hydroxypalmitic acid) (C 14 H 29 ) (H) C (OH) COOH
15. 2-Hydroxyoctadecanoic acid (Alpha hydroxystearic acid) (C 16 H 34 ) (H) C (OH) COOH
16. 2-Hydroxyeicosanoic acid (Alpha hydroxyarachidonic acid) (C 18 H 37 ) (H) C (OH) COOH
(2) Aralkyl And Aryl Alpha Hydroxyacids
1. 2-Phenyl 2-hydroxyethanoic acid (Mandelic acid) (C 6 H 5 ) (H) C (OH) COOH
2. 2,2-Diphenyl 2-hydroxyethanoic acid (Benzilic acid) (C 6 H 5 ) (C 6 H 5 ) C (OH) COOH
3. 3-Phenyl 2-hydroxypropanoic acid (Phenyllactic acid) (C 6 H 5 CH 2 ) (H) C (OH) COOH
4. 2-Phenyl 2-methyl 2-hydroxyethanoic acid (Atrolactic acid) (C 6 H 3 ) (CH 3 ) C (OH) COOH
5. 2-(4'-Hydroxyphenyl) 2-hydroxyethanoic acid (4-Hydroxymandelic acid) (HO--C 6 H 4 ) (H) C (OH) COOH
6. 2-(4'-Chlorophenyl) 2-hydroxyethanoic acid (4-Chloromandelic acid) (Cl --C 6 H 4 ) (H) C (OH) COOH
7. 2-(3'-Hydroxy-4'-methoxyphenyl) 2-hydroxyethanoic acid (3-Hydroxy-4-methoxymandelic acid) (HO--,CH 3 O--C 6 H 3 ) (H) C (OH) COOH
8. 2-(4'-Hydroxy-3'-methoxyphenyl) 2-hydroxyethanoic acid (4-Hydroxy-3-methoxymandelic acid) (HO--, CH 3 O--C 6 H 3 ) (H) C (OH) COOH
9. 3-(2'-Hydroxyphenyl) 2-hydroxypropanoic acid [3-(2'-Hydroxyphenyl) lactic acid] HO--C 6 H 4 --CH 2 (H) C (OH) COOH
10. 3-(4'-Hydroxyphenyl) 2-hydroxypropanoic acid [3-(4'-Hydroxyphenyl) lactic acid] HO--C 6 H 4 --CH 2 (H) C (OH) COOH
11. 2-(3', 4'-Dihydroxyphenyl) 2-hydroxyethanoic acid (3,4-Dihydroxymandelic acid) HO--,HO--C 6 H 3 (H) C (OH) COOH
(3) Polyhydroxy Alpha Hydroxyacids
1. 2,3-Dihydroxypropanoic acid (Glyceric acid) (HOCH 2 ) (H) C (OH) COOH
2. 2,3,4-Trihydroxybutanoic acid (Isomers; erythronic acid, threonic acid) HOCH 2 (HO)CH 2 (H) C (OH) COOH
3. 2,3,4,5-Tetrahydroxypentanoic acid (Isomers; ribonic acid, arabinoic acid, xylonic acid, lyxonic acid) HOCH 2 (HO)CH 2 (HO)CH 2 (H) C (OH) COOH
4. 2,3,4,5,6-Pentahydroxyhexanoic acid (Isomers; allonic acid, altronic acid, gluconic acid, mannoic acid, gulonic acid, idonic acid, galactonic acid, talonic acid) HOCH 2 (HO)CH 2 (HO)CH 2 (HO)CH 2 (H) C (OH) COOH
5. 2,3,4,5,6,7-Hexahydroxyheptanoic acid (Isomers; glucoheptonic acid, galactoheptonic acid etc.) HOCH 2 (HO) CH 2 (HO) CH 2 (HO) CH 2 (HO) CH 2 (H) C (OH) COOH
(4) Polycarboxylic Alpha Hydroxyacids
1. 2-Hydroxypropane-1,3-dioic acid (Tartronic acid) HOOC (H) C (OH) COOH
2. 2-Hydroxybutane-1,4-dioic acid (Malic acid) HOOC CH 2 (H) C (OH) COOH
3. 2,3-Dihydroxybutane-1,4-dioic acid (Tartaric acid) HOOC (HO)CH (H) C (OH) COOH
4. 2-Hydroxy-2-carboxypentane-1,5-dioic acid (Citric acid) HOOC CH 2 C (OH)(COOH) CH 2 COOH
5. 2,3,4,5-Tetrahydroxyhexane-1,6-dioic acid (Isomers; saccharic acid, mucic acid etc.) HOOC (CHOH) 4 COOH
(5) Lactone Forms
The typical lactone forms are gluconolactone, galactonolactone, glucuronolactone, galacturonolactone, gulonolactone, ribonolactone, saccharic acid lactone, pantoyllactone, glucoheptonolactone, mannonolactone, and galactoheptonolactone.
The second group of compounds which may be incorporated into amphoteric or pseudoamphoteric compositions for cosmetic conditions and dermatologic disorders, is organic carboxylic acids in which the alpha carbon of the acids is in keto form. The generic structure of such alpha ketoacids may be represented as follows:
(Ra) CO COO (Rb)
wherein Ra and Rb are H, alkyl, aralkyl or aryl group of saturated or unsaturated, isomeric or non-isomeric, straight or branched chain or cyclic form, having 1 to 25 carbon atoms, and in addition Ra may carry F, Cl, Br, I, OH, CHO, COOH and alkoxy group having 1 to 9 carbon atoms. The alpha ketoacids may be present as a free acid or an ester form, or in a salt form with an organic base or an inorganic alkali. The typical alkyl, aralkyl and aryl groups for Ra and Rb include methyl, ethyl, propyl, isopropyl, butyl, pentyl, octyl, lauryl, stearyl, benzyl and phenyl, etc.
In contrast to alpha hydroxyacids the ester form of alpha ketoacids has been found to be therapeutically effective for cosmetic and dermatologic conditions and disorders. For example, while ethyl lactate has a minimal effect, ethyl pyruvate is therapeutically very effective. Although the real mechanism for such difference is not known, we have speculated that the ester form of an alpha ketoacid is chemically and/or biochemically very reactive, and a free acid form of the alpha ketoacid is released in the skin after the topical application.
The representative alpha ketoacids and their esters which may be useful in amphoteric or pseudoamphoteric compositions for cosmetic conditions and dermatologic disorders are listed below:
1. 2-Ketoethanoic acid (Glyoxylic acid) (H) CO COOH
2. Methyl 2-ketoethanoate (H) CO COOCH 3
3. 2-Ketopropanoic acid (Pyruvic acid) CH 3 CO COOH
4. Methyl 2-ketopropanoate (Methyl pyruvate) CH 3 CO COOCH 3
5. Ethyl 2-ketopropanoate (Ethyl pyruvate) CH 3 CO COOC 2 H 5
6. Propyl 2-ketopropanoate (Propyl pyruvate) CH 3 CO COOC 3 H 7
7. 2-Phenyl-2-ketoethanoic acid (Benzoylformic acid) C 6 H 5 CO COOH
8. Methyl 2-phenyl -2-ketoethanoate (Methyl benzoylformate) C 6 H 5 CO COOCH 3
9. Ethyl 2-phenyl-2-ketoethanoate (Ethyl benzoylformate) C 6 H 5 CO COOC 2 H 5
10. 3-Phenyl-2-ketopropanoic acid (Phenylpyruvic acid) C 6 H 5 CH 2 CO COOH
11. Methyl 3-phenyl -2-ketopropanoate (Methyl phenylpyruvate) C 6 H 5 CH 2 CO COOCH 3
12. Ethyl 3-phenyl-2-ketopropanoate (Ethyl phenylpyruvate) C 6 H 5 CH 2 CO COOC 2 H 5
13. 2-Ketobutanoic acid C 2 H 5 CO COOH
14. 2-Ketopentanoic acid C 3 H 7 CO COOH
15. 2-Ketohexanoic acid C 4 H 9 CO COOH
16. 2-Ketoheptanoic acid C 5 H 11 CO COOH
17. 2-Ketooctanoic acid C 6 H 13 CO COOH
18. 2-Ketododecanoic acid C 10 H 21 CO COOH
19. Methyl 2-ketooctanoate C 6 H 13 CO COOCH 3
The third group of compounds which may be incorporated into amphoteric or pseudoamphoteric compositions for cosmetic and dermatologic conditions and disorders, is chemically related to alpha hydroxyacids or alpha ketoacids, and can be represented by their names instead of the above two generic structures. The third group of compounds include ascorbic acid, quinic acid, isocitric acid, tropic acid, trethocanic acid, 3-chlorolactic acid, cerebronic acid, citramalic acid, agaricic acid, 2-hydroxynervonic acid, aleuritic acid and pantoic acid.
II. Dimeric and Polymeric Forms of Hydroxyacids
When two or more molecules of hydroxycarboxylic acids either identical or non-identical compounds are reacted chemically to each other, dimeric or polymeric compounds will be formed. Such dimeric and polymeric compounds may be classified into three groups, namely (a) acyclic ester, (b) cyclic ester and (c) miscellaneous dimer and polymer.
(a) Acyclic ester. The acyclic ester of a hydroxycarboxylic acid may be a dimer or a polymer. The dimer is formed from two molecules of a hydroxycarboxylic acid by reacting the carboxyl group of one molecule with the hydroxy group of a second molecule. For example, glycolyl glycollate is formed from two molecules of glycolic acid by eliminating one mole of water molecule. Likewise, lactyl lactate is formed from two molecules of lactic acid. When two molecules of different hydroxycarboxylic acids are intermolecularly reacted, a different dimer is formed. For example, glycolyl lactate is formed by reacting the carboxyl group of lactic acid with the hydroxy group of glycolic acid. The polymer is formed in a similar manner but from more than two molecules of a hydroxycarboxylic acid. For example, glycoly glycoly glycollate is formed from three molecules of glycolic acid. Copolymer is formed from two or more than two different kinds of hydroxycarboxylic acids. For example, glycolyl lactyl glycollate is formed from two molecules of glycolic acid and one molecule of lactic acid.
The acyclic ester of dimeric and polymeric hydroxycarboxylic acids may be shown by the following chemical structure:
H[--O--C(Ra)(Rb)--CO--]n OH
wherein Ra,Rb═H, alkyl, aralkyl ar aryl group of saturated or unsaturated, isomeric or non-isomeric, straight or branched chain or cyclic form, having 1 to 25 carbon atoms, and n=1 or any numerical number, with a preferred number of up to 200. Ra and Rb in monomer unit 2, 3, 4 and so on may be the same or the different groups from that in monomer unit 1. For example, Ra,Rb═H in monomer unit 1, and Ra═CH 3 , Rb═H in monomer unit 2 when n=2 is a dimer called lactyl glycollate, because the first monomer is glycollate unit and the second monomer is lactic acid unit. The hydrogen atom in Ra and Rb may be substituted by a halogen atom or a radical such as a lower alkyl, aralkyl, aryl or alkoxy of saturated or unsaturated, isomeric or non-isomeric, straight or branched chain or cyclic form, having 1 to 9 carbon atoms. The dimer and polymer of a hydroxycarboxylic acid may be present as a free acid, ester or salt form with organic base or inorganic alkali.
The typical alkyl, aralkyl and aryl groups for Ra and Rb include methyl, ethyl, propyl, isopropyl, butyl, benzyl and phenyl. Representative acyclic esters of hydroxycarboxylic acids which may be useful for cosmetic conditions and dermatologic disorders are listed below:
1. Glycolyl glycollate (Glycolic acid glycollate) Ra,Rb═H in units 1 & 2, n=2
2. Lactyl lactate (Lactic acid lactate) Ra═CH 3 , Rb═H in units 1&2, n=2
3. Mandelyl mandellate Ra═C 6 H 5 , Rb═H in units 1 & 2, n=2
4. Atrolactyl atrolactate Ra═C 6 H 5 ,Rb═CH 3 in units 1 & 2, n=2
5. Phenyllactyl phenyllactate Ra═C 6 H 5 CH 2 , Rb═H, in units 1 & 2, n=2
6. Benzilyl benzillate Ra,Rb═C 6 H 5 in units 1 & 2, n=2
7. Glycolyl lactate Ra═CH 3 in unit 1, Ra═H in unit 2, Rb═H in units 1 & 2, n=2
8. Lactyl glycollate Ra═H in unit 1, Ra═CH 3 in unit 2, Rb═H in units 1 & 2, n=2
9. Glycolyl glycolyl glycollate Ra,Rb═H in units 1, 2 & 3, n=3
10. Lactyl lactyl lactate Ra═CH 3 , Rb═H in units 1, 2 & 3, n=3
11. Lactyl glycolyl lactate Ra═CH 3 in units 1 & 3, Ra═H in unit 2, Rb═H in units 1, 2 & 3, n=3
12. Glycolyl glycolyl glycolyl glycollate Ra,Rb═H in units 1, 2, 3 & 4, n=4
13. Lactyl lactyl lactyl lactate Ra═CH 3 , Rb═H in units 1, 2, 3 & 4, n=4
14. Glycolyl lactyl glycolyl lactyl glycollate Ra═H in units 1, 3 & 5, Ra═CH 3 in units 2 & 4, Rb═H in units 1, 2, 3, 4 & 5, n=5
15. Polyglycolic acid and polylactic acid
(b) Cyclic ester. The cyclic ester of a hydroxycarboxylic acid may also be a dimer or polymer, the most common type however, is a dimer form. The cyclic dimer may be formed from an identical monomer or different monomers. For example, glycolide is formed from two molecules of glycolic acid by removing two molecules of water, and lactide is formed from two molecules of lactic acid in the same manner. The cyclic ester of dimeric and polymeric hydroxycarboxylic acids may be shown by the following chemical structure:
[--O--C(Ra)(Rb)--CO--]n
wherein Ra,Rb═H, alkyl, aralkyl or aryl group of saturated or unsaturated, isomeric or non-isomeric, straight or branched chain or cyclic form, having 1 to 25 carbon atoms, and n=1 or any numerical number, however with a preferred number of 2. Ra and Rb in units 1, 2, 3 and so on may be the same or the different groups. For example, in glycolide Ra and Rb are H in both units 1 & 2, but in lactoglycolide Ra is H in unit 1, CH 3 in unit 2 and Rb is H in both units 1 & 2. The hydrogen atom in Ra and Rb may be substituted by a halogen atom or a radical such as a lower alkyl, aralkyl, aryl or alkoxy of saturated or unsaturated, isomeric or non-isomeric, straight or branched chain or cyclic form, having 1 to 9 carbon atoms.
The typical alkyl, aralkyl and aryl groups for Ra and Rb include methyl, ethyl, propyl, isopropyl, butyl, benzyl and phenyl. Representative cyclic esters of hydroxycarboxylic acids which may be useful for cosmetic conditions and dermatologic disorders are listed below:
1. Glycolide Ra,Rb═H, n=2
2. Lactide Ra═CH 3 , Rb═H in units 1 & 2, n=2
3. Mandelide Ra═C 6 H 5 , Rb═H in units 1 & 2, n=2
4. Atrolactide Ra═C 6 H 5 , Rb═CH 3 in units 1 & 2, n=2
5. Phenyllactide Ra═C 6 H 5 CH 2 , Rb═H in units 1 & 2, n=2
6. Benzilide Ra,Rb═C 6 H 5 in units 1 & 2, n=2
7. Methyllactide Ra,Rb═CH 3 in units 1 & 2, n=2
8. Lactoglycolide Ra═H in unit 1, Ra═CH 3 in unit 2 Rb═H in units 1 & 2, n=2
9. Glycolactide Ra═CH 3 in unit 1, Ra═H in unit 2 Rb═H in units 1 & 2, n=2
(c) Miscellaneous dimer and polymer. This group includes all the dimeric and polymeric forms of hydroxycarboxylic acids, which can not be represented by any one of the above two generic structures, such as those formed from tropic acid, trethocanic acid and aleuritic acid. When a hydroxycarboxylic acid has more than one hydroxy or carboxy group in the molecule a complex polymer may be formed. Such complex polymer may consist of acyclic as well as cyclic structures.
The following hydroxycarboxylic acids have more than one hydroxy groups: glyceric acid, gluconic acid and gluconolactone, galactonic acid and galactonolactone, glucuronic acid and glucuronolactone, ribonic acid and ribonolactone, galacturonic acid and galacturonolactone, ascorbic acid, gulonic acid and gulonolactone, glucoheptonic acid and glucoheptonolactone. These polyhydroxycarboxylic acids can form complex polymers with themselves or with other simple monohydroxymonocarboxylic acids.
The following hydroxycarboxylic acids have more than one carboxyl groups: malic acid, citric acid, citramalic acid, tartronic acid, agaricic acid and isocitric acid. These monohydroxypolycarboxylic acids can also form complex polymers with themselves or with other simple hydroxycarboxylic acids.
The following hydroxycarboxylic acids have more than one hydroxy and more than one carboxyl groups: tartaric acid, mucic acid and saccharic acid. These polyhydroxypolycarboxylic acids can form even more complex polymers with themselves or with other hydroxycarboxylic acids.
III. Combination Compositions
Any cosmetic and pharmaceutical agents may be incorporated into amphoteric or pseudoamphoteric compositions, or into compositions containing dimeric or polymeric forms of hydroxyacids with or without amphoteric or pseudoamphoteric systems to enhance therapeutic effects of those cosmetic and pharmaceutical agents to improve cosmetic conditions or to alleviate the symptoms of dermatologic disorder. Cosmetic and pharmaceutical agents include those that improve or eradicate age spots, keratoses and wrinkles; analgesics; anesthetics; antiacne agents; antibacterials; antiyeast agents; antifungal agents; antiviral agents; antidandruff agents; antidermatitis agents; antipruritic agents; antiemetics; antimotion sickness agents; antiinflammatory agents; antihyperkeratolytic agents; antidryskin agents; antiperspirants; antipsoriatic agents; antiseborrheic agents; hair conditioners and hair treatment agents; antiaging and antiwrinkle agents; antiasthmatic agents and bronchodilators; sunscreen agents; antihistamine agents; skin lightening agents; depigmenting agents; vitamins; corticosteroids; tanning agents; hormones; retinoids; topical cardiovascular agents and other dermatologicals.
Some examples of cosmetic and pharmaceutical agents are clotrimazole, ketoconazole, miconazole, griseofulvin, hydroxyzine, diphenhydramine, pramoxine, lidocaine, procaine, mepivacaine, monobenzone, erythromycin, tetracycline, clindamycin, meclocycline, hydroquinone, minocycline, naproxen, ibuprofen, theophylline, cromolyn, albuterol, retinoic acid, 13-cis retinoic acid, hydrocortisone, hydrocortisone 21-acetate, hydrocortisone 17-valerate, hydrocortisone 17-butyrate, betamethasone valerate, betamethasone dipropionate, triamcinolone acetonide, fluocinonide, clobetasol propionate, benzoyl peroxide, crotamiton, propranolol, promethazine, vitamin A palmitate and vitamin E acetate.
IV. Specific Compositions For Skin Disorders
We have discovered that topical formulations or compositions containing specific alpha hydroxyacids or alpha ketoacids, or related compounds are therapeutically very effective for certain skin disorders without utilizing any amphoteric or pseudoamphoteric systems. The alpha hydroxyacids and the related compounds include 2-hydroxyethanoic acid, 2-hydroxypropanoic acid, 2-methyl 2-hydroxypropanoic acid, 2-phenyl 2-hydroxyethanoic acid, 2,2-diphenyl 2-hydroxyethanoic acid, 2-phenyl 2-methyl 2-hydroxyethanoic acid and 2-phenyl 3-hydroxypropanoic acid. The alpha ketoacids and their esters include 2-ketopropanoic acid, methyl 2-ketopropanoate and ethyl 2-ketopropanoate. The mentioned skin disorders include warts, keratoses, age spots, acne, nail infections, wrinkles and aging related skin changes.
In general, the concentration of the alpha hydroxyacid, the alpha ketoacid or the related compound used in the composition is a full strength to an intermediate strength, therefore the dispensing and the application require special handling and procedures.
If the alpha hdyroxyacid, or the alpha ketoacid or the related compound at full strength (usually 95-100%) is a liquid form at room temperature Such as 2-hydroxypropanoic acid, 2-ketopropanoic acid, methyl 2-ketopropanoate and ethyl 2-ketopropanoate, the liquid compound with or without a gelling agent is directly dispensed as 0.5 to 1 ml aliquots in small vials.
If the alpha hydroxyacid, or the alpha ketoacid or the related compound at full strength is a solid form at room temperature such as 2-hydroxyethanoic acid, 2-methyl 2-hydroxypropanoic acid, 2-phenyl 2-hydroxyethanoic acid, 2,2-diphenyl 2-hydroxyethanoic acid and 2-phenyl 3-hydroxypropanoic acid, the solid compound is first dissolved in a minimal amount of vehicle or vehicle system such as water, or ethanol and propylene glycol with or without a gelling agent. For example, 2-hydroxyethanoic acid 70 g is dissolved in water 30 g, and the 70% strength solution thus obtained is dispensed as 0.5 to 1 ml aliquots in small vials. If a gelling agent is used, 0.5 to 3% of for example, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose or carbomer may be incorporated into the above solution.
To prepare an intermediate strength (usually 20-50%), the alpha hydroxyacid, alpha ketoacid or related compound either a liquid or solid form at room temperature is first dissolved in a vehicle or vehicle system such as water, acetone, ethanol, propylene glycol and butane 1,3-diol. For example, 2-hydroxyethanoic acid or 2-ketopropanoic acid 30 g is dissolved in ethanol 56 g and propylene glycol 14 g, and the 30% strength solution thus obtained is dispensed as 7 to 14 ml aliquots in dropper bottles.
For topical treatment of warts, keratoses, age spots, ache, nail infections, wrinkles or aging related skin changes, patients are advised to apply a small drop of the medication with a toothpick or a fine-caliber, commonly available artist's camel hair brush to affected lesions only and not surrounding skin. Prescribed applications have been 1 to 6 times daily for keratoses and ordinary warts of the hands, fingers, palms, and soles. For age spots, acne, nail infections, wrinkles and aging related skin changes topical applications have been 1 to 2 times daily.
Very often, frequency and duration of applications have been modified according to clinical responses and reactions of the lesions and the patient or responsible family member is instructed accordingly. For example, some clinical manifestations other than pain have been used as a signal to interrupt application. These manifestations include distinct blanching of the lesions or distinct peripheral erythema.
Alternatively, an office procedure may be adapted when a full strength of 2-ketopropanoic acid or 70% 2-hydroxyethanoic acid is used for topical treatment of age spots, keratoses, acne, warts or facial wrinkles.
We have found that the above mentioned alpha hydroxyacids, alpha ketoacids and related compounds are therapeutically effective for topical treatments of warts, keratoses, age spots, acne, nail infections, wrinkles and aging related skin changes.
Preparation of the Therapeutic Compositions
Amphoteric and pseudoamphoteric compositions of the instant invention may be formulated as solution, gel, lotion, cream, ointment, shampoo, spray, stick, powder or other cosmetic and pharmaceutical preparations.
To prepare an amphoteric or pseudoamphoteric composition in solution form at least one of the aforementioned amphoteric or pseudoamphoteric compounds and in combination at least one of the hydroxyacids or the related compounds are dissolved in a solution which may consist of ethanol, water, propylene glycol, acetone or other pharmaceutically acceptable vehicle. The concentration of the amphoteric or pseudoamphoteric compound may range from 0.01 to 10M, the preferred concentration ranges from 0.1 to 3M. The concentration of hydroxyacids or the related compounds may range from 0.02 to 12M, the preferred concentration ranges from 0.2 to 5M.
In the preparation of an amphoteric or pseudoamphoteric composition in lotion, cream or ointment form, at least one of the amphoteric or pseudoamphoteric compounds and one of the hydroxyacids or the related compounds are initially dissolved in a solvent such as water, ethanol and/or propylene glycol. The solution thus prepared is then mixed in a conventional manner with commonly available cream or ointment base such as hydrophilic ointment or petrolatum. The concentrations of amphoteric or pseudoamphoteric compounds and hydroxyacids used in the compositions are the same as described above.
Amphoteric and pseudoamphoteric compositions of the instant invention may also be formulated in a gel form. A typical gel composition of the instant invention utilizes at least one of the amphoteric or pseudoamphoteric compounds and one of the hydroxyacids or the related compounds are dissolved in a mixture of ethanol, water and propylene glycol in a volume ratio of 40:40:20, respectively. A gelling agent such as methyl cellulose, ethyl cellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carbomer or ammoniated glycyrrhizinate is then added to the mixture with agitation. The preferred concentration of the gelling agent may range from 0.1 to 4 percent by weight of the total composition.
Since dimeric and polymeric forms of hydroxyacids are less stable in the presence of water or the like vehicle, cosmetic and pharmaceutical compositions should be prepared as anhydrous formulations. Typical vehicles suitable for such formulations include mineral oil, petrolatum, isopropyl myristate, isopropyl palmitate, diisopropyl adipate, occtyl palmitate, acetone, squalene, squalane, silicone oils, vegetable oils and the like. Therapeutic compositions containing dimeric or polymeric forms of hydroxyacids do not require any incorporation of an amphoteric or pseudoamphoteric compound. The concentration of the dimeric or polymeric form of a hydroxyacid used in the composition may range from 0.1 to 100%, the preferred concentration ranges from 1 to 40%. Therapeutic compositions may be formulated as anhydrous solution, lotion, ointment, spray, powder or the like.
To prepare a combination composition in a pharmaceutically acceptable vehicle, a cosmetic or pharmaceutical agent is incorporated into any one of the above composition by dissolving or mixing the agent into the formulation.
The following are illustrative examples of formulations and compositions according to this invention. Although the examples utilize only selected compounds and formulations, it should be understood that the following examples are illustrative and not limited therefore, any of the aforementioned amphoteric or pseudoamphoteric compounds, hydroxyacids, dimeric or polymeric forms of hydroxyacids may be substituted according to the teachings of this invention in the following examples.
EXAMPLE 1
An amphoteric composition containing 1M 2-hydroxyethanoic acid and 0.5M L-arginine in solution form for dandruff or dry skin may be formulated as follows.
2-Hydroxyethanoic acid (glycolic acid) 7.6 g is dissolved in water 60 ml and propylene glycol 20 ml. L-Arginine 8.7 g is added to the solution with stirring until all the crystals are dissolved. Ethanol is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.0. An amphoteric composition formulated from 1M 2-hydroxyethanoic acid and 1M L-arginine has pH 6.3. The solution has pH 1.9 if no amphoteric compound is incorporated.
EXAMPLE 2
An amphoteric composition containing 1M 2-hydroxyethanoic acid and 0.5M L-lysine in a cream form for dry skin and other dermatologic and cosmetic conditions may be formulated as follows.
2-Hydroxyethanoic acid 7.6 g and L-lysine 7.3 g are dissolved in 30 ml of water, and the solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 3.3.
EXAMPLE 3
An amphoteric composition containing 1M 2-hydroxyethanoic acid and 0.5M 4-aminobutanoic acid in lotion form for cosmetic and dermatologic conditions may be formulated as follows.
2-Hydroxyethanoic acid 7.6 g and 4-aminobutanoic acid 5.2 g are dissolved in water 30 ml, and the solution is mixed with 50 g of an oil-in-water emulsion. The lotion thus obtained is made up to 100 ml in volume with more oil-in-water emulsion. The amphoteric composition thus formulated has pH 3.1.
EXAMPLE 4
A pseudoamphoteric composition containing 1M 2-hydroxyethanoic acid and 0.5M creatinine in solution form for cosmetic conditions and dermatologic disorders may be formulated as follows.
2-Hydroxyethanoic acid 7.6 g is dissolved in water 70 ml and propylene glycol 10 ml. Creatinine 5.7 g is added to the solution with stirring until all the crystals are dissolved. More water is added to make a total volume of the solution to 100 ml. The pseudoamphoteric composition thus formulated has pH 3.2. The composition has pH 4.0 when 1M instead of 0.5M creatinine is incorporated into the formulation.
EXAMPLE 5
An amphoteric composition containing 1M 2-hydroxyethanoic acid and 0.5M L-histidine in a cream form for dermatologic and cosmetic conditions may be formulated as follows.
2-Hydroxyethanoic acid 7.6 g and L-histidine 7.8 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 3.2.
EXAMPLE 6
An amphoteric composition containing 0.5M 2-hydroxyethanoic acid and 0.5M dipeptide of β-Ala-L-His for cosmetic and dermatologic conditions may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g and L-carnosine (β-alanyl-L-histidine) 11.3 g are dissolved in water 40 ml and propylene glycol 20 ml. After all the crystals have been dissolved sufficient amount of ethanol is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 4.5.
EXAMPLE 7
An amphoteric composition containing 0.5M 2-hydroxyethanoic acid and 0.5M cycloleucine for cosmetic and dermatologic conditions may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g and 1-aminocyclopentane-1-carboxylic acid (cycloleucine) 6.5 g are dissolved in water 40 ml and propylene glycol 20 ml. After all the crystals have been dissolved sufficient amount of ethanol is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.2.
EXAMPLE 8
A pseudoamphoteric composition containing 0.5M 2-hydroxyethanoic acid and 0.25M 1,12-diaminododecane for cosmetic and dermatologic conditions may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g and 1,12-diaminododecane 5 g are dissolved in water 40 ml and propylene glycol 20 ml. After all the crystals have been dissolved sufficient amount of ethanol is added to make a total volume of the solution to 100 ml. The pseudoamphoteric composition thus formulated has pH 4.2.
EXAMPLE 9
An amphoteric composition containing 0.5M 2-hydroxyethanoic acid and 5% protamine for cosmetic and dermatologic conditions may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g and protamine 5 g, isolated and purified from salmon sperm are dissolved in water 25 ml. The solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 3.2.
EXAMPLE 10
An amphoteric composition containing 1M 2-hydroxypropanoic acid and 0.5M L-arginine in solution form for dandruff or dry skin may be formulated as follows.
2-Hydroxypropanoic acid (DL-lactic acid) USP grade 9.0 g is dissolved in water 60 ml and propylene glycol 20 ml. L-Arginine 8.7 g is added to the solution with stirring until all the crystals are dissolved. Ethanol is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.1. An amphoteric composition formulated from 1M 2-hydroxypropanoic acid and 1M L-arginine has pH 6.9. The solution has pH 1.9 if no amphoteric compound is incorporated.
EXAMPLE 11
An amphoteric composition containing 1M 2-hydroxypropanoic acid and 0.5M L-lysine in a cream form for dry skin and other dermatologic and cosmetic conditions may be formulated as follows.
2-Hydroxypropanoic acid 9.0 g and L-lysine 7.3 g are dissolved in 30 ml of water, and the solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 3.6. An amphoteric composition formulated from 1M 2-hydroxypropanoic acid and 1M L-lysine has pH 8.4.
EXAMPLE 12
An amphoteric composition containing 1M 2-hydroxypropanoic acid and 0.5M 4-aminobutanoic acid in lotion form for cosmetic and dermatologic conditions may be formulated as follows.
2-Hydroxypropanoic acid 9.0 g and 4-aminobutanoic acid 5.2 g are dissolved in water 30 ml, and the solution is mixed with 50 g of an oil-in-water emulsion. The lotion thus obtained is made up to 100 ml in volume with more oil-in-water emulsion. The amphoteric composition thus formulated has pH 3.0
EXAMPLE 13
A pseudoamphoteric composition containing 1M 2-hydroxypropanoic acid and 0.5M creatinine in solution form for cosmetic conditions and dermatologic disorders may be formulated as follows.
2-Hydroxypropanoic acid 9.0 g is dissolved in water 70 ml and propylene glycol 10 ml. Creatinine 5.7 g is added to the solution with stirring until all the crystals are dissolved. More water is added to make a total volume of the solution to 100 ml. The pseudoamphoteric composition thus formulated has pH 3.3. The composition has pH 4.4 when 1M instead of 0.5M creatinine is incorporated into the formulation.
EXAMPLE 14
An amphoteric composition containing 1M 2-hydroxypropanoic acid and 1M L-histidine in a cream form for dermatologic and cosmetic conditions may be formulated as follows.
2-Hydroxypropanoic acid 9.0 g and L-histidine 15.5 g are dissolved in 35 ml of water, and the solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated as pH 4.9.
EXAMPLE 15
An amphoteric composition containing 1M 2-hydroxypropanoic acid and 1M dipeptide of Gly-Gly for cosmetic and dermatologic conditions may be formulated as follows.
2-Hydroxypropanoic acid 9.0 g and glycylglycine 13.2 g are dissolved in water 40 ml and propylene glycol 20 ml. After all the crystals have been dissolved sufficient amount of ethanol is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.0.
EXAMPLE 16
An amphoteric composition containing 1M 2-methyl-2-hydroxypropanoic acid and 0.5M L-arginine in solution form for dandruff or dry skin may be formulated as follows.
2-Methyl-2-hydroxypropanoic acid (methyllactic acid) 10.4 g is dissolved in water 60 ml and propylene glycol 20 ml. L-Arginine 8.7 g is added to the solution with stirring until all the crystals are dissolved. Ethanol is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.3. An amphoteric composition formulated from 1M 2-methyl-2-hydroxypropanoic acid and 1M L-arginine has pH 6.5. The solution has pH 1.9 if no amphoteric compound is incorporated.
EXAMPLE 17
An amphoteric composition containing 1M 2-methyl-2-hydroxypropanoic acid and 0.5M 4-aminobutanoic acid in a cream form for dry skin and other dermatologic and cosmetic conditions may be formulated as follows.
2-Methyl-2-hydroxypropanoic acid 10.4 g and 4-aminobutanoic acid 5.2 g are dissolved in 30 ml of water, and the solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 3.2.
EXAMPLE 18
An amphoteric composition containing 1M 2-methyl-2-hydroxypropanoic acid and 1M dipeptide of Gly-Gly in lotion form for cosmetic and dermatologic conditions may be formulated as follows.
2-Methyl-2-hydroxypropanoic acid 10.4 g and glycylglycine 13.2 g are dissolved in water 30 ml, and the solution is mixed with 50 g of an oil-in-water emulsion. The lotion thus obtained is made up to 100 ml in volume with more oil-in-water emulsion. The amphoteric composition thus formulated-has pH 3.0.
EXAMPLE 19
A pseudoamphoteric composition containing 1M 2-methyl-2-hydroxypropanoic acid and 0.5M creatinine in solution form for cosmetic conditions and dermatologic disorders may be formulated as follows.
2-Methyl-2-hydroxypropanoic acid 10.4 g is dissolved in water 70 ml and propylene glycol 10 ml. Creatinine 5.7 g is added to the solution with stirring until all the crystals are dissolved. More water is added to make a total volume of the solution to 100 ml. The pseudoamphoteric composition thus formulated has pH 3.4. The composition has pH 4.4 when 1M instead of 0.5M creatinine is incorporated into the formulation.
EXAMPLE 20
An amphoteric composition containing 0.5M 2-phenyl-2-hydroxyethanoic acid and 0.5M L-histidine in a cream form for dermatologic and cosmetic conditions may be formulated as follows.
2-Phenyl 2-hydroxyethanoic acid (mandelic acid) 7.6 g and L-histidine 7.8 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 5.0. The composition has pH 2.2 if no amphoteric compound is incorporated.
EXAMPLE 21
An amphoteric composition containing 0.5M 2-phenyl-2-hydroxyethanoic acid and 0.5M L-lysine for cosmetic and dermatologic conditions may be formulated as follows.
2-Phenyl 2-hydroxyethanoic acid 7.6 g and L-lysine 7.3 g are dissolved in 25 ml of water. The solution thus obtained is mixed with an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated for pH 4.6.
EXAMPLE 22
A pseudoamphoteric composition containing 0.5M 2-phenyl 2-hydroxyethanoic acid and 0.5M creatinine for cosmetic and dermatologic conditions may be formulated as follows.
2-Phenyl 2-hydroxyethanoic acid 7.6 g and creatinine 5.7 g are dissolved in 30 ml of water, and the solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 4.6.
EXAMPLE 23
An amphoteric composition containing 0.5M 2-phenyl 2-hydroxyehanoic acid and 0.5M L-citrulline for cosmetic and dermatologic conditions may be formulated as follows.
2-Phenyl 2-hydroxyethanoic acid 7.6 g and L-citrulline 8.8 g are dissolved in water 30 ml, and the solution is mixed with 50 g of an oil-in-water emulsion. The lotion thus obtained is made up to 100 ml in volume with more oil-in-water emulsion. The amphoteric composition thus formulated has pH 3.0.
EXAMPLE 24
An amphoteric composition containing 1M citric acid and 1M L-arginine for cosmetic conditions and dermatologic disorders may be formulated as follows.
Citric acid 19.2 g is dissolved in water 50 ml and propylene glycol 10 ml. L-Arginine 17.4 g is added to the solution with stirring until all the crystals are dissolved. More water is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.0. The composition has pH 1.8 if no amphoteric compound is incorporated.
EXAMPLE 25
A pseudoamphoteric composition containing 1M citric acid and 1M creatinine for dermatologic and cosmetic conditions may be formulated as follows.
Citric acid 19.2 g and creatinine 11.3 g are dissolved in 40 ml of water, and the solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 3.7.
EXAMPLE 26
An amphoteric composition containing 1M malic acid and 1M L-arginine for cosmetic and dermatologic conditions may be formulated as follows.
2-Hydroxybutanedioic acid (DL-malic acid) 13.4 g and L-arginine 17.4 g are dissolved in water 40 ml and propylene glycol 20 ml. After all the crystals have been dissolved sufficient amount of water is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.3. The composition has pH 1.8 if no amphoteric compound is incorporated.
EXAMPLE 27
A pseudoamphoteric composition containing 1M malic acid and 0.5M creatinine for cosmetic and dermatologic conditions may be formulated as follows.
DL-Malic acid 13.4 g and creatinine 5.7 g are dissolved in water 40 ml and propylene glycol 20 ml. After all the crystals have been dissolved sufficient amount of water is added to make a total volume of the solution to 100 ml. The pseudoamphoteric composition thus formulated has pH 3.0. The composition has pH 3.8 when 1M instead of 0.5M creatinine is incorporated into the formulation.
EXAMPLE 28
An amphoteric composition containing 1M tartaric acid and 1M L-arginine for cosmetic and dermatologic conditions may be formulated as follows.
2,3-Dihydroxybutanedioic acid (DL-tartaric acid) 15.9 g and L-arginine 17.4 g are dissolved in water 40 ml and propylene glycol 20 ml. After all the crystals have been dissolved sufficient amount of water is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.0. The composition has pH 1.7 if no amphoteric compound is incorporated.
EXAMPLE 29
A pseudoamphoteric composition containing 1M tartaric acid and 1M creatinine for cosmetic and dermatologic conditions may be formulated as follows.
DL-Tartaric acid 15.0 g and creatinine 11.3 g are dissolved in 35 ml of water. The solution thus obtained is mixed with sufficient amount of an oil-in-water emulsion to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 3.4.
EXAMPLE 30
An amphoteric composition containing 1M gluconolactone and 0.5M L-arginine for cosmetic and dermatologic conditions may be formulated as follows.
Gluconolactone 17.8 g and L-arginine 8.7 g are dissolved in water 60 ml and propylene glycol 10 ml. After all the crystals have been dissolved sufficient water is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.1. The composition has pH 5.9 when 1M instead of 0.5M L-arginine is incorporated into the formulation. If no amphoteric compound is incorporated the pH of the composition is 1.8.
EXAMPLE 31
An amphoteric composition containing 1M gluconolactone and 0.5M 4-aminobutanoic acid for cosmetic and dermatologic conditions may be formulated as follows.
Gluconolactone 17.8 g and 4-aminobutanoic acid 5.2 g are dissolved in water 60 ml and propylene glycol 10 ml. After all the crystals ave been dissolved sufficient water is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 3.2.
EXAMPLE 32
An amphoteric composition containing 1M gluconolactone and 1M dipeptide of Gly-Gly for cosmetic and dermatologic conditions may be formulated as follows.
Gluconolactone 17.8 g and glycylglycine 13.2 g are dissolved in water 50 ml and propylene glycol 5 ml. More water is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH. 3.1.
EXAMPLE 33
A pseudoamphoteric composition containing 1M gluconolactone and 0.5M creatinine for cosmetic conditions and dermatologic disorders may be formulated as follows.
Gluconolactone 17.8 g and creatinine 5.7 g are dissolved in water 60 ml and propylene glycol 10 ml. More water is added to make a total volume of the solution to 100 ml. The pseudoamphoteric composition thus formulated has pH 3.2. The composition has pH 4.8 when 1M instead of 0.5M creatinine is incorporated into the formulation.
EXAMPLE 34
A pseudoamphoteric composition containing 1M pyruvic acid and 1M creatinine for dermatologic and cosmetic conditions may be formulated as follows.
2-Ketopropanoic acid (pyruvic acid) 8.8 g and creatinine 11.3 g are dissolved in water 25 ml. The solution thus obtained is mixed with sufficient amount of an oil-in-water emulsiom to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 3.4.
EXAMPLE 35
An amphoteric composition containing 0.5M benzilic acid and 0.5M L-lysine for cosmetic and dermatologic conditions may be formulated as follows.
2,2-Diphenyl 2-hydroxyethanoic acid (benzilic acid) 11.4 g and L-lysine 7.3 g are dissolved in water 40 ml and propylene glycol 20 ml. After all the crystals have been dissolved sufficient amount of ethanol is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 4.9. The composition has. pH 2.7 if no amphoteric compound is incorporated.
EXAMPLE 36
An amphoteric composition containing 0.5M benzilic acid and 0.5M L-histidine for cosmetic and dermatologic conditions may be formulated as follows.
Benzilic acid 11.4 g and L-histidine 7.8 g are dissolved in water 40 ml and propylene glycol 20 ml. Ethyl cellulose 2 g is added with stirring, and sufficient amount of ethanol is added to make a total volume of the gel to 100 ml. The amphoteric gel composition thus formulated has pH 5.0.
EXAMPLE 37
A pseudoamphoteric composition containing 0.5M benzilic acid and 0.5M creatinine for cosmetic and dermatologic conditions may be formulated as follows.
Benzilic acid 11.4 g and creatinine 5.7 g are dissolved in water 40 ml and propylene glycol 20 ml. Sufficient amount of ethanol is added to make a total volume of the solution to 100 ml. The amphoteric composition thus formulated has pH 4.9.
EXAMPLE 38
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxyethanoic acid and 0.05% betamethasone dipropionate in a cream form for dermatologic disorders may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g and creatinine 5.7 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with 50 g of an oil-in-water emulsion. Betamethasone dipropionate 1% in ethanol solution 5 ml is added to the above mixture. More oil-in-water emulsion is added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.2.
EXAMPLE 39
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxyethanoic acid and 0.05% clobetasol propionate in a cream form for dermatologic disorders may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g and creatinine 5.7 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with 50 g of an oil-in-water emulsion. Clobetasol propionate 1% in acetone solution 5 ml is added to the above mixture. More oil-in-water emulsion is added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.2.
EXAMPLE 40
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxyethanoic acid and 0.1% triamcinolone acetonide in a cream form for dermatologic disorders may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g and creatinine 5.7 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with 50 g of an oil-in-water emulsion. Triamcinolone acetonide 2% solution of acetone:ethanol (50:50), 5 ml is added to the above mixture. More oil-in-water emulsion is added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.2.
EXAMPLE 41
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxyethanoic acid and 0.2% 5-fluorouracil in a cream form for dermatologic disorders may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g and creatinine 5.7 g are dissolved in 20 ml of water, and the solution thus obtained is mixed with 50 g of an oil-in-water emulsion. 5-Fluorouracil 2% solution of propylene glycol: water (95:5), 10 ml is added to the above mixture. More oil-in-water emulsion is added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.1.
EXAMPLE 42
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxypropanoic acid and 0.05% betamethasone dipropionate in a cream form for dermatologic disorders may be formulated as follows.
2-Hydroxypropanoic acid 4.5 g and Creatinine 5.7 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with 50 g of a oil-in-water emulsion. Betamethasone dipropionate 1% in ethanol solution 5 ml is added to the above mixture. More oil-in-water emulsion is added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.1.
EXAMPLE 43
A pseudoamphoteric composition containing in combination 0.5M hydroxypropanoic acid and 0.05% clobetasol propionate in a cream form for dermatologic disorders may be formulated as follows.
2-Hydroxypropanoic acid 4.5 g and creatinine 5.7 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with 50 g of an oil-in-water emulsion. Clobetasol propionate 1% in acetone solution 5 ml is added to the above mixture. More oil-in-water emulsion is added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.1.
EXAMPLE 44
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxypropanoic acid and 0.1% triamcinolone acetonide in a cream form for dermatologic disorders may be formulated as follows.
2-Hydroxypropanoic acid 4.5 g and creatinine 5.7 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with 50 g of an oil-in-water emulsion. Triamcinolone acetonide 2% solution of acetone:ethanol (50:50), 5 ml is added to the above mixture. More oil-in-water emulsion is added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.1.
EXAMPLE 45
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxypropanoic acid and 0.2% 5-fluorouracil in a cream form for dermatologic disorders may be formulated as follows.
2-Hydroxypropanoic acid 4.5 g and creatinine 5.7 g are dissolved in 20 ml of water, and the solution thus obtained is mixed with 50 g of an oil-in-water emulsion. 5-Fluorouracil 2% solution of propylene glycol:water (95:5), 10 ml is added to the above mixture. More oil-in-water emulsion is added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.1.
EXAMPLE 46
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxyethanoic acid and 2% clotrimazole in a cream form for athlete's foot and other fungal infections may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g, clotimazole 2 g and creatinine 5.7 g are dissolved in water 20 ml and propylene glycol 5 ml, and the solution thus obtained is mixed with enough amount of an oil-in-water emulsion to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.2.
EXAMPLE 47
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxyethanoic acid and 2% erythromycin in solution form for acne may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g, erythromycin 2 g and creatinine 5.7 g are dissolved in water 25 ml, ethanol 40 ml and propylene glycol 15 ml. More water is then added to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.2.
EXAMPLE 48
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxyethanoic acid and 1% ketoconazole in a cream form for fungal infections may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g, ketoconazole 1 g and creatinine 5.7 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with enough amount of an oil-in-water emulsion to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.2.
EXAMPLE 49
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxypropanoic acid and 2% clotrimazole in a cream form for fungal infections may be formulated as follows.
2-Hydroxypropanoic acid 3.8 g, clotrimazole 2 g and creatinine 5.7 g are dissolved in 25 ml of water, and the solution thus obtained is mixed with enough amount of an oil-in-water emulsion to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated has pH 4.1.
EXAMPLE 50
A pseudoamphoteric composition containing in combination 0.5M 2-hydroxyethanoic acid and 2% tetracycline in a gel form for dermatologic disorders may be formulated as follows.
2-Hydroxyethanoic acid 3.8 g, tetracycline 2 g, creatinine 5.7 g, xantham gum 0.2 g, carbomer-941 1 g, propylene glycol 5 ml, ethanol 20 ml and enough amount of water are homogenized to make a total volume of 100 ml. The pseudoamphoteric composition thus formulated for acne and oily skin has pH 4.2.
EXAMPLE 51
An amphoteric composition containing 0.2M aleuritic acid and 0.1M L-lysine in a solution form for cosmetic and dermatologic conditions may be formulated as follows.
Aleuritic acid 6.1 g and L-lysine 1.5 g are dissolved in sufficient amount of a solution from ethanol:propylene glycol 80:20 to make a total volume of 100 ml. The amphoteric composition thus formulated has pH 6.4.
EXAMPLE 52
A typical composition containing a dimeric form of alpha hydroxyacid in solution for acne, dandruff, and as a skin cleanser may be formulated as follows.
Glycolide powder 1.0 g is dissolved in ethanol 89 ml and propylene glycol 10 ml. The composition thus formulated has pH 4.0, and contains 1% active ingredient.
EXAMPLE 53
A typical composition containing a dimeric form of alpha hdyroxyacid in ointment for dry skin, psoriasis, eczema, pruritus, wrinkles and other skin changes associated with aging may be formulated as follows.
Glycolide powder 2.0 g is mixed uniformly with petrolatum 66 g and mineral oil 32 g. The composition thus formulated contains 2% active ingredient.
EXAMPLE 54
A typical composition containing a full strength or a high concentration of an alpha hydroxyacid, alpha ketoacid or closely related compound for topical treatments of warts, keratoses, acne, age spots, nail infections, wrinkles and aging related skin changes may be prepared as follows.
If the alpha hydroxyacid, alpha ketoacid or closely related compound at full strength is a liquid form at room temperature such as 2-hydroxypropanoic acid, 2-ketopropanoic acid, methyl 2-ketopropanoate and ethyl 2-ketopropanoate, the compound is directly dispensed as 0.5 to 1 ml aliquots in small vials. If the compound is a solid form at room temperature such as 2-hydroxyethanoic acid and 2-methyl 2-hydroxypropanoic acid, it is first dissolved in minimal amount of an appropriate solvent or solvent system such as water or ethanol and propylene glycol with- or without a gelling agent. For example, 2-hydroxyethanoic acid 70 g is dissolved in water 30 ml, and the 70% strength 2-hydroxyethanoic acid thus obtained is dispensed as 0.5 to 1 ml aliquots in small vials. If a gelling agent is used, methyl cellulose or hydroxyethyl cellulose 1 g may be added to the above solution.
EXAMPLE 55
A typical composition containing an intermediate strength of an alpha hydroxyacid, alpha ketoacid or closely related compound for topical treatment of warts, keratoses, acne, nail infections, age spots, wrinkles and aging related skin changes may be prepared as follows.
2-Hydroxyethanoic acid or 2-ketopropanoic acid 40 g is dissovled in ethanol 54 g and propylene glycol 6 g, and the 40% strength solution thus obtained is dispensed as 5 to 10 ml aliquots in dropper bottles.
TEST RESULTS
In order to determine whether amphoteric and pseudoamphoteric compositions of the instant invention were therapeutically effective for various cosmetic conditions and dermatologic disorders, a total of more than 90 volunteers and patients participated in these studies. Some participating subjects were given two preparations; an amphoteric or pseudoamphoteric composition containing an alpha hydroxyacid or the related compound, and a vehicle placebo. Others were given multiple preparations containing a known pharmaceutical agent such as a corticosteroid with or without incorporation of an amphoteric or pseudoamphoteric composition consisting of an alpha hydroxyacid or the related compound of the instant invention. The amphoteric and pseudoamphoteric compositions were formulated according to the Examples described in the previous section.
1. Common dry skin
Human subjects having ordinary dry skin or with moderate degrees of dry skin as evidenced by dryness, flaking and cracking of the skin were instructed to apply topically the lotion, cream or ointment containing an alpha hydroxyacid or the related compound in amphoteric or pseudoamphoteric composition, on the affected area of the skin. Topical application, two to three times daily, was continued for two to four weeks.
In all the 28 subjects tested, the feeling of the skin dryness disappeared within a week of topical application. The rough and cracked skin became less pronounced and the skin appeared normal and felt smooth after several days of topical treatment. The alpha hydroxyacids and the related compounds which have been found to be therapeutically effective when incorporated into the amphoteric or pseudoamphoteric compositions for dry skin are as follows:
2-hydroxyethanoic acid (glycolic acid), 2-hydroxypropanoic acid (lactic acid), 2-methyl-2-hydroxypropanoic acid (methyllactic acid), phenyl 2-hydroxyethanoic acid (mandelic acid), phenyl 2-methyl-2-hydroxyethanoic acid (atrolactic acid), 3-phenyl-2-hydroxypropanoic acid (phenyllactic acid), diphenyl 2-hydroxyethanoic acid (benzilic acid), gluconolactone, tartaric acid, citric acid, saccharic acid, malic acid, tropic acid, glucuronic acid, galacturonic acid, gluconic acid, 3-hydroxybutanoic acid, quinic acid, ribonolactone, glucuronolactone, galactonolactone, pyruvic acid, methyl pyruvate, ethyl pyruvate, phenylpyruvic acid, benzoylformic acid and methyl benzoylformate.
The ordinary dry skin conditions, once restored to normal appearing skin, remained improved for some time until causes of dry skin, such as low humidity, cold weather, excessive contact pressure, detergents, soaps, solvents, chemicals, etc., again caused recurrence of the dry skin condition. On continued use it was also found that twice daily topical application of an amphoteric or pseudoamphoteric composition containing an alpha hydroxyacid or the related compound of the instant invention prevented the development of new dry skin lesions.
2. Severe dry skin
In severe dry skin, the skin lesions are different from the ordinary dry skin. A main cause of severe dry skin is inherited genetic defects of the skin. The involved skin is hyperplastic, fissured and has thick adherent scales. The degree of thickening is such that lesions are palpably and visually elevated. The thickened adherent scales cause the surface of involved skin to be markedly rough and uneven. These two attributes of thickness and texture can be quantified to allow objective measurement of degree of improvement from topically applied test materials as follows:
__________________________________________________________________________DEGREE OF IMPROVEMENTNone Mild Moderate Substantial Complete(0) (1+) (2+) (3+) (4+)__________________________________________________________________________ThicknessHighly Detectable Readily Barely Normalelevated reduction apparent elevated thickness reductionTextureVisibly Palpably Uneven but Slightly Visibly andrough rough not rough uneven palpably smooth__________________________________________________________________________
By means of such parameters, degrees of change in lesions can be numerically recorded and comparisons made of one treated site to another.
In order to evaluate the amphoteric and pseudoamphoteric compositions of the instant invention, a total of 6 patients having severe dry skin conditions were treated with the compositions containing an alpha hydroxyacid or the related compound.
Tested areas were of a size convenient for topical applications, i.e., circles 5 cm in diameter demarcated with a plastic ring of that size inked on a stamp pad. The medicinal lotions or creams were topically applied by the patient in an amount sufficient to cover the treatment sites. Applications were made three times daily and without occlusive dressings. Applications were discontinued at any time when resolutions of the lesion on the treatment area was clinically judged to be complete.
The test results of amphoteric and pseudoamphoteric compositions containing the following alpha hydroxyacids or the related compounds on patients with severe dry skin are summarized as follows:
4+ Effectiveness; glycolic acid, lactic acid, methyllactic acid, mandelic acid, tropic acid, atrolactic acid and pyruvic acid.
3+ Effectiveness; benzilic acid, gluconolactone, malic acid, tartaric acid, citric acid, saccharic acid, methyl pyruvate, ethyl pyruvate, phenyllactic acid, phenylpyruvic acid, glucuronic acid and 3-hydroxybutanoic acid.
2+ Effectiveness; mucic acid, ribonolactone, 2-hydroxydodecanoic acid, quinic acid, benzoylformic acid and methyl benzoylformate.
3. Psoriasis
The involved skin in psoriasis is hyperplastic (thickened), erythematous (red or inflamed), and has thick adherent scales. The degree of thickening is such that lesions are elevated up to 1 mm above the surface of adjacent normal skin; erythema is usually an intense red; the thickened adherent scales cause the surface of involved skin to be markedly rough and uneven. These three attributes of thickness, color and texture can be quantified to allow objective measurement of degree of improvement from topically applied test materials as follows.
__________________________________________________________________________DEGREE OF IMPROVEMENT None Mild Moderate Substantial Complete (0) (1+) (2+) (3+) (4+)__________________________________________________________________________THICKNESS Highly Detectable Readily Barely Normal elevated reduction apparent elevated thickness reductionTEXTURE Visibly Palpably Uneven but Slightly Visibly and rough rough not rough uneven palpably smoothCOLOR Intense Red Dark Pink Light Pink Normal Skin Red Color__________________________________________________________________________
By means of such parameters, degree of improvement in psoriatic lesions can be numerically recorded and comparisons made of one treated site to another.
Patients having psoriasis participated in this study. Amphoteric and pseudoamphoteric compositions containing both an alpha hdyroxyacid or the related compound and a corticosteroid were prepared according to the Examples. Compositions containing only a corticosteroid were also prepared and included in the comparison test. Test areas were kept to minimal size convenient for topical application, i.e., circles approximately 4 cm in diameter. The medicinal compositions were topically applied by the patient in an amount (usually about 0.1 milliliter) sufficient to cover the test site. Applications were made two to three times daily and without occlusive dressings. Test periods usually lasted for two to four weeks. The test results on patients having psoriasis are summarized on the following table.
______________________________________Topical Effects on Psoriasis ofAntipsoriatic Compositions TherapeuticCompositions* Effectiveness______________________________________Hydrocortisone 2.5% alone 1+With lactic acid 2+With glycolic acid 2+With ethyl pyruvate 2+With methyl pyruvate 2+With benzilic acid 2+With pyruvic acid 2+With methyllactic acid 2+Hydrocortisone 17-valerate 0.2% alone 2+With lactic acid 3+With glycolic acid 3+With benzilic aicd 3+With ethyl pyruvate 3+With methyl pyruvate 3+With gluconolactone 3+With pyruvic acid 3+Betamethasone dipropionate 0.05% alone 3+With lactic acid 4+With glycolic acid 4+With ethyl pyruvate 4+With methyl pyruvate 4+With mandelic acid 4+With benzilic acid 4+Clobetasol propionate 0.05% alone 3%With lactic acid 4+With glycolic acid 4+With ethyl pyruvate 4+With methyl pyruvate 4+With methyllactic acid 4+With mandelic acid 4+With tropic acid 4+With benzilic acid 4+______________________________________ *Except the "alone" preparations, all others were amphoteric or pseudoamphoteric compositions containing 0.2 to 2M alpha hydroxyacids or related compounds.
We have also found that an amphoteric or pseudoamphoteric composition containing an alpha hydroxyacid or the related compound in combination with an antimetabolite agent such as 5-fluorouracil with or without additional incorporation of a corticosteroid is therapeutically effective for topical treatment of psoriasis.
4. Eczema
In a topical treatment of eczema patients, hydrocortisone alone at 2.5% or hydrocortisone 17-valerate alone at 0.2% would achieve only 2+ improvement, and betamethasone dipropionate or clobetasol propionate alone at 0.05% would achieve only a 3+=0 improvement on all the eczema patients tested. Test results of amphoteric and pseudoamphoteric compositions containing both a corticosteroid and one of the following alpha hydroxyacids or the related compounds are shown as follows:
3+ Effectiveness; hydrocortisone 2.5% or hydrocortisone 17-valerate 0.2% plus lactic acid, glycolic acid, mandelic acid, ethyl pyruvate, gluconolactone, benzilic acid or ribonolactone.
4+ Effectiveness; betamethasone dipropionate or clobetasol propionate 0.05% plus lactic acid, glycolic acid, mandelic acid, ethyl pyruvate, methyl pyruvate, benzilic acid, gluconolactone, citric acid, tartaric acid or methyllactic acid.
5. Oily Skin and Skin Cleanse
Human subjects having oily skin or blemished skin as well as acne patients having extremely oily skin participated in this study. Amphoteric and pseudoamphoteric compositions containing alpha hydroxyacids or the related compounds were formulated in solution or gel form.
Each participating subject received a solution or a gel preparation containing an alpha hydroxyacid or a related compound in an amphoteric or pseudoamphoteric composition. The participating subjects were instructed to apply topically the solution or gel medication on the affected areas of forehead or other part of the face. Three times daily applications were continued for 2 to 6 weeks.
The degree of improvement of oily skin as well as the rate of improvement of acne lesions were clinically evaluated. Most participants reported that oiliness of skin disappeared within one to two weeks of topical administration, and the skin so treated became smooth and soft. Many participating subjects preferred gel preparations than solution compositions. It was found that all the participants showed substantial improvements on oily skin and acne lesions by six weeks of topical administration of amphoteric or pseudoamphoteric compositions containing alpha hydroxyacids or the related compounds of the instant invention.
Those alpha hydroxyacids and the related compounds which have been found to be therapeutically effective for oily skin and as skin cleansers include: benzilic acid, glycolic acid, lactic acid, methyllactic acid, mandelic acid, pyruvic acid, ethyl pyruvate, methyl pyruvate, tropic acid, malic acid, gluconolactone, 3-hydroxybutanoic acid, glycolide and polyglycolic acid. As a skin cleanser for oily skin or ache-prone skin, the amphoteric or pseudoamphoteric composition containing an alpha hydroxyacid or the related compound may also be incorporated with other dermatologic agents. For example, an amphoteric gel composition may consist of both an alpha hydroxyacid and erythromycin or tetracycline.
6. Acne
Amphoteric and pseudoamphoteric compositions containing alpha hydroxyacids or the related compounds of the instant invention in a solution or gel form were provided to patients having comedongenic and/or papulopustular lesions of acne. Each participating patient was instructed to apply topically the composition on the involved areas of the skin such as forehead, face and chest. Three times daily administration was continued for 6 to 12 weeks.
The degree and rate of improvement on acne lesions were clinically evaluated. It was found that acne lesions consisting mainly of comedones improved substantially after 6 to 8 weeks of topical administration with the amphoteric or the pseudoamphoteric composition containing an alpha hydroxyacid or the related compound. The time for complete clearing of comedongenic acne treated with the amphoteric or pseudoamphoteric composition of the instant invention varied from 6 to 12 weeks.
As a topical treatment for papulopustular and/or pustular acne the amphoteric or pseudoamphoteric composition containing an alpha hydroxyacid or the related compound may incorporate in addition an antiacne agent. The antiacne agents include antibiotics such as erythromycin, tetracycline, clindamycin, meclocycline and minocycline, and retinoids such as retinoic acid. Such combination compositions have been found to be therapeutically more effective for topical treatment of severe ache.
7. Age Spots
Many small and large discolored lesions, commonly called age spots on the face and the back of the hands are benign keratoses, if they are not variants of actinic keratoses. Very few of such age spots are true lentigines, therefore alpha hydroxyacids and the related compounds may be effective in eradicating most age spots without concurrent use of skin bleaching agents such as hydroquinone and monobenzone. However, additional beneficial effects have been found when a skin bleaching agent such as hydroquinone or monobenzone is also incorporated into the compositions of the instant invention for age spots involving pigmented lesions.
Amphoteric and pseudoamphoteric compositions containing alpha hydroxyacids or the related compounds, with or without incorporation of hydroquinone were provided to volunteer subjects and patients having age spot keratoses, melasma, lentigines and/or other pigmented lesions. Each participating subject received two products, i.e., with or without the addition of 2% hydroquinone to the amphoteric or pseudoamphoteric composition containing an alpha hydroxyacid or the related compound.
The volunteer subjects and patients were instructed to apply topically one medication on one side of the body such as left side of the face or on the back of the left hand, and the other medication on the other side of the body such as on right side of the face or on the back of the right hand. Specific instructions were given to the participating subjects that the medications were applied three times daily to the lesions of age spot keratoses, melasmas, lentigines and/or other pigmented lesions. Clinical photos were taken of participating subjects before the initiation of the topical treatment and every 4 weeks during the course of treatment.
At the end of 4 to 8 weeks, improvement of age spot keratoses was clinically discernible. After 4 to 6 months of topical treatment, substantial improvement of age spot keratoses occurred in the majority of subjects tested. Complete eradication of age spot keratoses occurred after 6 to 9 months of topical administration with the amphoteric or pseudoamphoteric compositions of the instant inventions.
Amphoteric or pseudoamphoteric compositions containing both an alpha hydroxyacid or the related compound and hydroquinone were judged to be more effective in eradicating pigmented age spots, melasma, lentigines and other pigmented lesions.
The alpha hydroxyacids and the related compounds which have been found to be therapeutically effective for age spots with or without combination with hydroquinone include glycolic acid, lactic acid, methyllactic acid, mandelic acid, pyruvic acid, methyl pyruvate, ethyl pyruvate, benzilic acid, gluconolactone, malic acid, tartaric acid, citric acid and tropic acid. For flat or slightly elevated seborrheic keratoses on the face and/or the back of the body, amphoteric or pseudoamphoteric compositions containing higher concentrations of alpha hydroxyacids or the related compounds have been found to be effective in eradicating such lesions.
Actinic keratoses may be successfully treated with amphoteric or pseudoamphoteric compositions containing alpha hydroxyacids or the related compounds in combination with an antimetabolite agent such as 5-fluorouracil.
8. Warts
Eradications of common warts by topical application of amphoteric or pseudoamphoteric compositions require higher than usual concentrations of alpha hydroxyacids or the related compounds in the formulations. The amphoteric or pseudoamphoteric compositions were formulated as a liquid or light gel form, and dispensed usually as 0.5-1 ml aliquots in small vials.
Topical applications were made discreetly to wart lesions by adult patients or by responsible adult family members. For ordinary usual warts of hands, fingers, palms and soles topical applications were made 2 to 4 times daily, and were continued for 2 to 6 weeks. Generally, the overlying stratum corneum of the wart lesion change in appearance after several weeks topical application of the composition. In most cases, the wart lesion simply fell off. The skin then healed normally without forming any scars.
We have also found that when a dermatologic agent such as 5-fluorouracil is incorporated into the amphoteric or pseudoamphoteric compositions containing alpha hydroxyacids or the related compounds, the medications have been very effective for topical treatment of warts without using higher concentrations of alpha hydroxyacids or the related compounds.
The alpha hydroxyacids and the related compounds which have been found to be therapeutically effective for topical treatment of warts with or without incorporation of 5-fluorouracil include glycolic acid, lactic acid, pyruvic acid, ethyl pyruvate, methyl pyruvate and mandelic acid.
Topical formulations and compositions containing specific alpha hydroxyacids, alpha ketoacids or the related compounds at full strengths or high to intermediate concentrations prepared according to Examples 54 and 55, without utilizing amphoteric or pseudoamphoteric systems, have also been tested for ordinary warts of the hands, fingers, palms and soles. Participating patients have been advised to apply a small drop of the medication with a toothpick or a fine caliber brush to the center of a wart lesion only. Prescirbed applications have been 3 to 6 times daily, and are continued until the patient feels pain.
For the more rough-surfaced wart, the duration of application has been as short as one or a few days. For lesions with more compact, less permeable stratum corneum, the time to experience gpain has been longer. Frequency and duration of applications have been modified according to other clinical responses and reactions of lesions, and the patient or responsible family member is instructed accordingly.
For example, some clinical manifestations other than pain have also been used as a signal to interrupt application. These manifestations have included distinct blanching of the lesions or distinct peripheral erythema. Very often, discomfort is the usual signal of clinical reactions.
Generally, the overlying stratum corneum of the wart lesions became loose, and the whole wart lesion simply fell off. The skin then healed normally without forming any scars.
9. Athlete's Foot and Nail Infections
Amphoteric and pseudoamphoteric compositions containing both an antifungal agent and one of the alpha hydroxyacids or the related compounds were provided to patients having frequent recurrence of fungal infections involving the foot. The antifungal agents include clotrimazole, miconazole, ketoconazole and griseofulvin. When both feet but not toe nails were involved in the infection, the patients were instructed to apply topically the compositions of the instant invention on the left foot, and a brand-name antifungal product on the right foot. Three times daily applications were continued for one to four weeks. The degree and rate of improvement on skin lesions were clinically evaluated, and comparison was made one side of the body against the other. It was found that the skin lesions improved much faster with the amphoteric or pseudoamphoteric compositions containing both the antifungal agent and the alpha hydroxyacid or the related compound. The alpha hydroxyacids or the related compounds seemed to enhance the efficacies of the antifungal agents, and also to eliminate the discomforts such as itching, tingling, burning and irritation due to fungal infections. When toe nails were not involved the infected skin generally healed within one to two weeks from topical application of the amphoteric or pseudoamphoteric composition containing both an antifungal agent and an alpha hydroxyacid or the related compound.
Fungal infections of the nails are very difficult to treat, because antifungal products to date are not therapeutically effective for topical treatment of nails. One of the reasons is that most antifungal drugs have not been formulated as bioavailable forms in the commercial products. When toe nails were involved in the infections, patients were provided with amphoteric or pseudoamphoteric compositions containing in combination an antifungal agent and an alpha hydroxyacid or an alpha ketoacid at higher concentrations ranging from 20 to 99%, dispensed as 1-2 ml aliquots in small vials. The patients were instructed to apply topically the compositions discreetly to the infected nail surface by means of a fine calibre paint brush. the technique was the same as for application of nail polish, that is careful avoidance of contact with lateral nail folds or any peri-ungual skin. Once or twice daily applications were continued for 2 to 8 weeks.
As mentioned above, while brand-name antifungal products are usually not effective against fungus infections within or underneath the nail, it was found that the amphoteric or pseudoamphoteric compositions containing an antifungal agent and an alpha hydroxyacid or alpha ketoacid were therapeutically effective in eradicating fungal infections of the nails. Such treatment may cause in some instances the treated nail plate to become loose and eventually fell off from the nail bed. This happened quite naturally without any feeling of pain nor bleeding, and the skin lesion healed quickly with normal growth of a new nail.
10. Wrinkles
Wrinkles of skin may be due to natural aging and/or sun damage. Most fine wrinkles on the face are due to natural or innate aging, while coarse wrinkles on the face are the consequence of actinic or sun damage. Although the real mechanism of wrinkles formation in the skin is still unknown, it has been shown that visible fine wrinkles are due to diminution in the number and diameter of elastic fibers in the papillary dermis, and also due to atrophy of dermis as well as reduction in subcutaneous adipose tissue. Histopathology and electron microscopy studies indicate that coarse wrinkles are due to excessive deposition of abnormal elastic materials in the upper dermis and thickening of the skin. At present there are no commercial products which have been found to be therapeutically effective for topical eradication of wrinkles, although retinoic acid (tretinoin) has been shown to be beneficial for sun damaged skin.
In order to determine whether the amphoteric or pseudoamphoteric composition containing the alpha hydroxyacids, alpha ketoacids or the related compounds are therapeutically effective for wrinkles, patients and volunteer subjects participated in this study. The participants were instructed to apply the formulations of the instant invention twice daily on areas of facial wrinkles for 4 to 12 months. All participants were told to avoid sun exposure, and to use sunscreen products if exposure to sunlight was unavoidable. Photographs of each side of the face for each participant were taken at the beginning of the study and repeated at one to three-month intervals. The participants were asked not to wear any facial make-up at the time of each office visit. Standardized photographic conditions were used including the use of same lot of photographic film, the same light source at two feet from the face, aimed at a locus on the frontal aspect of each cheek. Each time photographs were taken with camera aimed perpendicular to the cheek. At the end of study twenty two participants had been entered into the study for at least four months. Clinical evaluations and review of photographs have revealed substantial reductions in facial wrinkles of the temporal region and cheek area on at least one side of the face in eighteen cases. Degree of improvement and reduction in wrinkles has been evaluated and determined to be mild to moderate in six participants but very substantial in twelve participants.
The alpha hydroxyacids, alpha ketoacids and other related compounds including their lactone forms which may be incorporated into the amphoteric and pseudoamphoteric compositions for cosmetic conditions and dermatologic disorders such as dry skin, acne, age spots, keratoses, warts and skin wrinkles or in combination with other dermatologic agent, to enhance therapeutic effects include the following:
(1) Alkyl Alpha Hydroxyacids
2-Hydroxyethanoic acid (Glycolic acid), 2-Hydroxypropanoic acid (Lactic acid), 2-Methyl 2-hydroxypropanoic acid (Methyllactic acid), 2-Hydroxybutanoic acid, 2-Hydroxypentanoic acid, 2-Hydroxyhexanoic acid, 2-Hydroxyheptanoic acid, 2-Hydroxyoctanoic acid, 2-Hydroxynonanoic acid, 2-Hydroxydecanoic acid, 2-Hydroxyundecanoic acid, 2-Hydroxydodecanoic acid (Alpha hydroxylauric acid), 2-Hydroxytetradecanoic acid (Alpha hydroxymyristic acid), 2-Hydroxyhexadecanoic acid (Alpha hydroxypalmitic acid), 2-Hydroxyoctadecanoic acid (Alpha hydroxystearic acid), 2-Hydroxyeicosanoic acid (Alpha hydroxyarachidonic acid).
(2) Aralkyl And Aryl Alpha Hydroxyacids
2-Phenyl 2-hydroxyethanoic acid (Mandelic acid), 2,2-Diphenyl 2-hydroxyethanoic acid (Benzilic acid), 3-Phenyl 2-hydroxypropanoic acid (Phenyllactic acid), 2-Phenyl 2-methyl 2-hydroxyethanoic acid (Attolactic acid), 2-(4'-Hydroxyphenyl) 2-hydroxyethanoic acid, 2-(4'-Clorophenyl) 2-hydroxyethanoic acid, 2-(3'-Hydroxy-4'-methoxyphenyl) 2-hydroxyethanoic acid, 2-(4'-Hydroxy-3'-methoxyphenyl) 2-hydroxyethanoic acid, 3-(2'-Hydroxyphenyl) 2-hydroxypropanoic acid, 3-(4'-Hydroxyphenyl) 2-hydroxypropanoic acid, 2-(3',4'-Dihydroxyphenyl) 2-hydroxyethanoic acid.
(3) Polyhydroxy Alpha Hydroxyacids
2,3-Dihydroxypropanoic acid (Glyceric acid), 2,3,4-Trihydroxybutanoic acid (Isomers; erythronic acid, threonic acid), 2,3,4,5-Tetrahydroxypentanoic acid (Isomers; ribonic acid, arabinoic acid, xylonic acid, lyxonic acid), 2,3,4,5,6-Pentahydroxyhexanoic acid (Isomers; aldonic acid, altronic acid, gluconic acid, mannoic acid, gulonic acid, idonic acid, galactonic acid, talonic acid),. 2,3,4,5,6,7-Hexahydroxyheptanoic acid (Isomers; glucoheptonic acid, galactoheptonic acid, etc.)
(4) Polycarboxylic Alpha Hydroxyacids
2-Hydroxypropane-1,3-dioic acid (Tartronic acid), 2-Hydroxybutane-1,4-dioic acid (Malic acid), 2,3-Dihydroxybutane-1,4-dioic acid (Tartaric acid), 2-Hydroxy-2-carboxypentane-1,5-dioic acid (Citric acid), 2,3,4,5-Tetrahydroxyhexane-1,6-dioic acid (Isomers; saccharic acid, mucic acid, etc.)
(5) Alpha Hydroxyacid Related Compounds
Ascorbic acid, quinic acid, isocitric acid, tropic acid, 3-chlorolactic acid, trethocanic acid, cerebronic acid, citramalic acid, agaricic acid, 2-hydroxynervonic acid and aleuritic acid.
(6) Alpha Ketoacids And Related Compounds
2-Ketoethanoic acid (Glyoxylic acid), Methyl 2-ketoethanoate, 2-Ketopropanoic acid (Pyruvic acid), Methyl 2-ketopropanoate (Methyl pyruvate), Ethyl, 2-ketopropanoate (Ethyl pyruvate), Propyl 2-ketopropanoate (Propyl pyruvate), 2-Phenyl-2-ketoethanoic acid (Benzoylformic acid), Methyl 2-phenyl-2-ketoethanoate (MEthyl benzoylformate), Ethyl 2-phenyl-2-ketoethanoate (Ethyl benzoylformate), 3-Phenyl-2-ketopropanoic acid (Phenylpyruvic acid), Methyl 3-phenyl-2-ketopropanoate (Ethyl phenylpyruvate), 2-Ketobutanoic acid, 2-Ketopentanoic acid, 2-Ketohexanoic acid, 2-Ketoheptanoic acid, 2-Ketooctanoic acid, 2-Ketododecanoic acid, Methyl 2-ketooctanoate.
The amphoteric and pseudoamphoteric compounds which may be incorporated into the compositions of the instant invention for cosmetic and dermatologic conditions include amino acids, peptides, polypeptides, proteins and the like compounds such as creatinine and creatine.
The dimeric and polymeric forms of alpha hydroxyacids and the related comopounds which may be incorporated into the compositions of the instant invention include acyclic esters and cyclic ester; for example, glycolyl glycollate, lactyl lactate, glycolide, lactide, polyglycolic acid and polylactic acid.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims and all changes which come within the meaning and equivalency of the claims are therefore intended to be embraced therein. | Methods for visibly reducing a skin wrinkle and for reversing the effect of aging on human facial skin involving comprising topically applying to the wrinkle and/or affected facial skin gulonic acid or gulonolactone. |
TECHNICAL FIELD
The present invention relates to a pneumatic tire which enhances steering stability by providing a bead reinforcing layer having a reinforcing cord between a bead core and a carcass ply.
BACKGROUND TECHNIQUE
In recent years, as output and performance of automobiles are enhanced, tires are also strongly required to enhance the steering stability together with riding comfort.
In a pneumatic tire, it is known that the steering stability can be enhanced by increasing the tire lateral rigidity. Therefore, a reinforcing layer using steel cord or organic fiber cord is conventionally provided over a wide range from a bead portion to a sidewall portion to enhance the flexural rigidity of the sidewall.
However, if such a reinforcing layer is used, the tire vertical rigidity is increased and thus, the riding comfort is deteriorated. Further, stress is prone to be concentrated on an outer end of the reinforcing layer. Especially when the reinforcing layer is used for a high performance tire in which a tire aspect ratio is reduced to 55% or lower and a ground-contact width and a ground-contact area are increased, a flexible region of the sidewall portion becomes narrow and stress is concentrated more. Thus, there is a tendency that the endurance is deteriorated.
Thereupon, the present inventor focused attention on a fact that not only the tire lateral rigidity but also twisting rigidity of the bead portion largely affected the steering stability, and researched. As a result, the inventor found that the tire vertical rigidity could be maintained at low level and the steering stability could be enhanced without deteriorating the riding comfort if a reinforcing layer in which reinforcing cords were arranged at a predetermined angle and which had a folded-back portion was formed around the bead core without projecting the reinforcing layer from a bead apex rubber, and the bead core and the bead apex rubber were formed integral with each other, and the twisting rigidity of the bead portion was enhanced.
The steering stability can be enhanced also by increasing the width of the bead core to increase the twisting rigidity and to enhance the fitting performance between the bead core and a rim. In such a case, however, since the steel amount of the bead core and a rubber amount of the bead apex rubber are increased, there is a problem that the tire weight is increased and the fuel performance is deteriorated.
Based on an idea that a predetermined reinforcing layer is provided around a bead core, it is an object of the present invention to provide a pneumatic tire capable of enhancing the steering stability without deteriorating the riding comfort and without excessively increasing the tire weight.
SUMMARY OF THE INVENTION
To achieve the object, the present invention provides a pneumatic tire, comprising a carcass including a carcass ply having a ply body portion which extends from a tread portion to a bead core of a bead portion through a sidewall portion and which is continuously provided with a ply folded-up portion folded up around the bead core from its inner side to its outer side in the tire axial direction, and a bead apex rubber passing between the ply body portion and the ply folded-up portion and extending radially outward of the tire from a radially outer surface of the bead core, wherein
the bead portion is provided with a bead reinforcing layer which is arranged from an inner portion of the bead core located inward in the tire axial direction through a bottom portion passing radially inward and which is connected to an outer portion of the bead core outward in the tire axial direction and which is arranged at an angle of 20 to 60° with respect to a tire circumferential direction,
the outer portion includes a main portion which extends radially outward of the tire beyond the radially outer surface of the bead core to a region adjacent to the bead apex rubber, and a folded-back portion which is folded back at a radially outer end and terminated radially inward of the radially outer surface of the bead core,
the inner portion passes between the bead core and the ply body portion, and the outer portion passes between the bead core and the ply folded-up portion.
It is preferable that a width H 1 of the folded-back portion of the bead reinforcing layer in the radial direction is 5 to 40 mm. It is preferable that a radial height H 2 of the outer portion of the bead reinforcing layer from a bead base line is 1.5 to 4.5 times a radial height H 3 of the bead apex rubber, and is smaller than a radial height H 4 of the bead apex rubber. It is preferable that a radial height H 5 of the ply folded-up portion of the carcass ply is greater than the height H 4 of the bead apex rubber.
In this specification, the term “bead base line” means a line in the tire axial direction passing through a bead diameter position defined in a standard on which tires are based.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a tire according to an embodiment of the present invention;
FIG. 2 is an enlarged sectional view of a bead portion together with a reinforcing layer; and
FIG. 3 is a perspective view showing the reinforcing layer together with a bead core and a bead apex rubber.
DETAILED DESCRIPTION OF THE INVENTION
An example of the present invention will be explained with reference to the drawings. In this example, the pneumatic tire of the invention is a high performance passenger automobile tire having a tire aspect ratio of 55% or lower.
As shown in FIG. 1 , the pneumatic tire 1 includes a carcass 6 extending from a tread portion 2 to a bead core 5 of a bead portion 4 through a sidewall portion 3 , and a belt layer 7 disposed on the inner side of the tread portion 2 and on the outer side of the carcass 6 . The bead portion 4 is provided with a bead apex rubber 8 extending from a radially-outer surface of the tire of the bead core 5 to radially outward of the tire.
The belt layer 7 comprises two or more, in this example, two belt plies 7 A and 7 B in which high elastic belt cords are arranged in a tire circumferential direction at an angle of 10 to 35° for example. Inclination directions of the belt plies 7 A and 7 B are changed such that the belt cords intersect with each other between the plies. With this configuration, the belt rigidity is enhanced, and substantially the entire width of the tread portion 2 is strongly reinforced with a hoop effect. A steel cord or an organic fiber cord having high modulus such as aromatic polyamide fiber is preferably used as the belt cord.
In this example, in order to enhance a binding force with respect to the belt layer 7 and to enhance the high speed endurance, a band layer 9 is disposed on an outer side of the belt layer 7 . The band layer 9 includes a band cord which is helically wound in the tire circumferential direction at an angle of 5° or less for example. The band layer 9 extends such as to wrap at least an outer end of the belt layer 7 in the tire axial direction.
The carcass 6 comprises one or more, in this example, one carcass ply 6 A in which a carcass cord is arranged at an angle of 75 to 90° with respect to the tire circumferential direction. The carcass ply 6 A is integrally provided with a ply body portion 6 a extending between the bead cores 5 and 5 , and with a ply folded-up portion 6 b which is folded up around the bead core 5 from the inner side to the outer side in the tire axial direction on both ends of the ply body portion 6 a . An organic fiber cord such as nylon, rayon, polyester, and aromatic polyamide can preferably be used as the carcass cord.
Next, the bead apex rubber 8 passes between the ply body portion 6 a and the ply folded-up portion 6 b of the carcass 6 , and has a triangular cross section which is tapered radially outward of the tire.
In this example, in order to secure the tire rigidity required for the high performance tire, a radial height H 4 of the bead apex rubber 8 from the bead base line BL is set in a range of 0.25 to 0.5 times a height HT of a tire cross section. A radial height H 5 of the ply folded-up portion 6 b from the bead base line BL is set greater than the height H 4 , thereby forming an extending portion 6 b 1 extending beyond the bead apex rubber 8 . The extending portion 6 b 1 and the ply body portion 6 a are adjacent to each other. With this configuration, the bead apex rubber 8 is completely covered and the tire rigidity is further enhanced.
In this invention, in order to further enhance the steering stability, the bead portion 4 is provided with a bead reinforcing layer 10 .
As shown in FIGS. 2 and 3 , the bead reinforcing layer 10 comprises one cord ply in which reinforcing cords 11 are arranged at an angle θ (20 to 60°) with respect to the tire circumferential direction. Organic fiber cord such as nylon, polyester, rayon, and aromatic polyamide can be used as the reinforcing cord 11 . Nylon cord is especially preferable because the thickness of the cord can be increased by folding the same.
The bead reinforcing layer 10 comprises an inner portion 10 a located on the inner side of the bead core 5 in the tire axial direction, a bottom portion 10 b passing radially inward of the bead core 5 , and an outer portion 10 c located on the outer side of the bead core 5 in the tire axial direction. These portions 10 a , 10 b and 10 c are continuously connected to one another to form the U-shape.
The inner portion 10 a passes between the bead core 5 and the ply body portion 6 , and the outer portion 10 c passes between the bead core 5 and the ply folded-up portion 6 b . At least the outer portion 10 c , in this example, both the outer portion 10 c and the inner portion 10 a extend beyond the radially outer surface 5 s of the bead core 5 , radially outward, and extends to a region Y which is adjacent to the bead apex rubber 8 .
Thus, the bead reinforcing layer 10 brings the bead core 5 and the bead apex rubber 8 into tight contact with each other to wrap them in the U-shape and integrally and strongly couples the bead core 5 and the bead apex rubber 8 to each other.
The outer portion 10 c includes a main portion C 1 which is connected to the bottom portion 10 b and extends to the region Y which is adjacent to the bead apex rubber 8 , and a folded-back portion C 2 which is folded back at a radial outer end Ce of the main portion C 1 and superposed on the main portion C 1 and extends radially inward. The folded-back portion C 2 is terminated radially inward of the radially outer surface 5 s of the bead core 5 .
A cord angle θ of the bead reinforcing layer 10 is in a range of 20 to 60° . Thus, the reinforcing cords 11 intersect with each other at an angle of 2×θ to form a strong intersecting structure between the main portion C 1 and the folded-back portion C 2 . With this structure, and with effect of the integral structure between the bead core 5 and the bead apex rubber 8 , the twisting rigidity of the bead portion 4 can be effectively enhanced, and the steering stability can be enhanced.
In the bead reinforcing layer 10 , since radial heights H 6 and H 2 of the inner portion 10 a and the outer portion 10 c from the bead base line BL are smaller than the radial height H 4 of the bead apex rubber 8 , the tire's vertical rigidity is restrained from being increased, and the deterioration of the riding comfort is suppressed.
In order to enhance the steering stability, it is preferable that a width H 1 of the folded-back portion C 2 in the radial direction is in a range of 5 to 40 mm. If the width H 1 is less than 5 mm, the twisting rigidity is insufficient, and if the width H 1 exceeds 40 mm, the riding comfort is deteriorated.
For the same reason, it is preferable that the radial height H 2 of the outer portion 10 c is 1.5 to 4.5 times the radial height H 3 of the bead core 5 . If the height H 2 is less than 1.5 times, the twisting rigidity is insufficient, and if the height H 2 exceeds 4.5 times, the riding comfort is deteriorated.
Since the outer portion 10 c of the bead reinforcing layer 10 is lower than the bead apex rubber 8 , the stress concentration on the outer end Ce can be reduced. Since the ply folded-up portion 6 b covers the outer end Ce, bead damage such as cord loose can be suppressed.
Since the bead reinforcing layer 10 is formed with the folded-back portion C 2 , the bead core 5 is displaced axially inward by a distance corresponding to the thickness of the folded-back portion C 2 . As a result, the fitting performance with respect to the rim is enhanced, and this configuration also enhances the steering stability.
Although the preferred example of the present invention has been described in detail, the invention is not limited to the illustrated example, and the various changes and modifications may be made in the invention.
EMBODIMENT
Tires of 215/45ZR17 size were prototyped based on the specifications shown in Table 1. The steering stability, riding comfort and weight of the prototyped tire were measured and compared with each other. Specifications not shown in Table 1 are substantially the same. The test method is as follows:
(1) Steering Stability
The tires were mounted on all rims (17×7JJ) of a passenger vehicle (Japanese FR vehicle, displacement of 2500 cc) under internal pressure of 200 kPa, and the vehicle was run on a dry asphalt road at a speed of 120 km/H. The straight running stability and lane change stability at that time were evaluated by a driver's sensory evaluation on a scale of 10 while a comparative example was defined as 5. A greater value indicates more excellent result.
(2) Riding Comfort
The same test vehicle was run on an asphalt road (good road), and the riding comfort was evaluated by a driver's sensory evaluation on a scale of 10 while a comparative example was defined as 5. A greater value indicates more excellent result.
(3) Tire Weight
The weight of one tire was measured.
TABLE 1
Comparative
Comparative
Embodiment
Embodiment
Embodiment
Embodiment
Embodiment
example 1
example 2
1
2
3
4
5
Bead reinforcing
Absence
Presence
Presence
Presence
Presence
Presence
Presence
layer
Reinforcing cord
—
Nylon
Nylon
Nylon
Nylon
Nylon
Nylon
Cord angle θ (°)
—
50
50
50
50
20
60
Presence or
—
Absence
Presence
Presence
Presence
Presence
Presence
Absence of folded-
back portion
Heights (mm)
H1
—
—
10
20
30
20
20
H2
—
35
35
35
35
35
35
H3
6
6
6
6
6
6
6
H4
45
45
45
45
45
45
45
H5
60
60
60
60
60
60
60
H6
—
15
15
15
15
15
15
Bead core (*1)
4S × 4T
5S × 4T
4S × 4T
4S × 4T
4S × 4T
4S × 4T
4S × 4T
Steering stability
5.0
6.0
6.0
6.5
6.5
6.5
6.5
Riding comfort
7.0
6.5
6.5
6.5
6.0
6.0
5.5
Tire weight (kg)
9.8
10.3
10.1
10.1
10.1
10.1
10.1
(*1) This is a tape bead structure, and “nS × mT” means that n-number of bead wires are arranged in the widthwise direction and m-number of bead wires are arranged in the height direction.
INDUSTRIAL APPLICABILITY
Since the pneumatic tire of the invention is provided with a bead reinforcing layer having a predetermined structure around the bead core. Therefore, it is possible to enhance the steering stability without deteriorating the riding comfort and without excessively increasing the tire weight. | A pneumatic tire, comprising a bead part ( 4) having a bead reinforcement layer ( 10) continuously extending from the inside part ( 10 a) of a bead core ( 5) positioned on the axial inside of the tire to the outside part ( 10 c) thereof on the axial outside of the tire through a bottom part ( 10 b) passing the radial inside of the tire, the bead reinforcement layer ( 10) further comprising reinforcement cords ( 11) arranged at an angle of 20 to 60deg relative to the circumferential direction of the tire, the outside part ( 10 c) further comprising a main part (C 1) extending to an area (Y) adjacent to a bead apex rubber ( 8) and a folded part (C 2) folded up at the radial outer end (Ce) thereof, wherein the folded part (C 2) terminates on the radial inside of the radial outer surface ( 5 s) of the bead core ( 5). |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to propulsion apparatus, and more particularly to propulsion apparatus which utilize unbalanced centrifugal forces to achieve unidirectional movement of an object.
2. Description of the Prior Art
A number of propulsion apparatus utilizing the principal of an unbalanced centrifugal force have been employed in the past. However, they are all constructed such that they create intermittent motion as opposed to continuous motion, and they are mechanically complex and inefficient thereby rendering them relatively expensive to manufacture and operate.
The prior art suggests that such unidirectional propulsion apparatus utilizing unbalanced centrifugal forces can be used to move objects on the land, water or in the air. While this is true, probably one of the most important possible applications is in conjunction with the acceleration of space vehicles which are out of the influence of the earth's gravitational pull, as such propulsion apparatus are otherwise relatively inefficient when used under the influence of the earth's gravity.
At present, space vehicles travelling between planets and which are not under the influence of the earth's gravity have been able to achieve only speeds of between 31,000 and 32,000 miles per hour. To achieve greater speeds would require the craft to carry considerable extra quantities of fuel, which is impractical. Accordingly, the use of a simple propulsion apparatus utilizing the principles of an unbalanced centrifugal force which is driven by solar energy becomes appealing under such conditions in order to continually accelerate the space craft when it is under minimal gravitational influences.
Probably the simplest form of propulsion apparatus which does not propel itself by a force acting against an external medium, such as land, water or air, but is rather propelled by a reaction created internally within the apparatus itself is the direct push propulsion unit of Llamozas described in U.S. Pat. No. 2,636,340. Llamozas discloses a propulsion apparatus which consists of a piston slidably received within a closed cylinder which has no ingress or egress. The piston is caused to extend into the cylinder thereby compressing the air contained therein to a small volume, at which point the force holding the piston is released allowing the piston to be propelled within the cylinder due to the force exerted thereon by the compressed gas. The reaction of the cylinder working against the piston of heavier mass thus causes the cylinder to be propelled in a direction opposite to the direction of movement of the piston.
However, such a device, while being functional, is relatively inefficient and in addition propels the apparatus with rough intermittent motion instead of a smooth flowing continuous motion.
Instead of using unbalanced unidirectional forces as taught by Llamozas for propelling an object, a number of propulsion apparatus were developed which utilized an unbalanced centrifugal force, which in essence utilized the same basic principles as Llamozas, but permits the use of a plurality of propelling devices within the single apparatus instead of one propulsion mechanism alone. For example, see Laskowitz, U.S. Pat. No. 1,953,964, which utilizes an annular series of interconnected weights placed on radial arms which are eccentrically rotated about a common axis within a housing thereby creating an unbalanced centrifugal force imparting a unidirectional thrust to the housing. While Laskowitz does not use a compressed gas as taught by Llamozas, nevertheless the same principles are involved in that propulsion is created due to unbalanced forces set up within the unit or apparatus itself.
Other examples of such propulsion apparatus utilizing an unbalanced centrifugal force are illustrated in Great Britain Pat. No. 770,555 issued to Andrew Reid II and U.S. Pat. No. 3,555,915 issued to H. W. Young, Jr.
However, each of these apparatus is relatively mechanically complex in that a relatively large number of mechanically moveable parts is required and they are also relatively inefficient due to the losses created by excessive mechanical friction between mechanical parts. In addition, the propulsion motion created by these apparatus in nevertheless intermittent, even though their overall motion may be smoother than that experienced from the Llamozas apparatus, thereby adding to the inefficiency and causing undesirable vibrations to be imparted to the object being propelled.
U.S. Pat. No. 3,584,515 issued to Laszlo B. Matyas discloses a propulsion apparatus which also utilizes an unbalanced centrifugal force. Matyas discloses a propulsion apparatus which contains a central mass of liquid having a relatively high specific gravity, such as mercury, and provides an annular series of a large number of pistons which unitarily rotate about an axis with the mercury confined therebetween, and the pistons are cyclically operated to continually force the liquid from one side of the axis of rotation to the other thereby creating an unbalanced centrifugal force.
It can be noted from studying this particular structure that it is mechanically very complex and would therefore be relatively expensive to manufacture and would likely have a relatively high rate of failure as compared to the other prior art propulsion devices.
While the large number of pistons provided in an annular array in the Matyas disclosure does tend to smooth out the propulsion motion of the apparatus, nevertheless, the motion is still somewhat intermittent as opposed to being continuous.
It is the principal object of the present invention to eliminate the aforementioned disadvantages of the prior art propulsion devices and to provide a propulsion apparatus which operates on the principal of utilizing an unbalanced centrifugal force to obtain unidirectional motion which is continuous as opposed to being intermittent, and which in addition is mechanically simpler and more efficient than the apparatus of the prior art.
SUMMARY OF THE INVENTION
The continuous motion propulsion apparatus of the present invention generally comprises a moveable frame which rotatably supports an annular channel means which rotates in a plane perpendicular to its axis of rotation about its center. A body of liquid is contained within the channel means which is rotated about its axis to centrifugally distribute the liquid annularly therein. A deflection means is positioned in the annular channel means to deflect the liquid contained therein inwardly at a predetermined position relative to an outside reference to create an unbalanced centrifugal force and thereby propel the apparatus with continuous motion.
The annular channel means is generally provided within a closed housing in which the liquid, which is preferably of a relatively high specific gravity such as mercury, is housed, and the housing is supported for rotation on a shaft.
The deflection means or deflector depends radially outward from the shaft within the housing, and may physically be constructed in a number of different manners. In its simplest form, the deflector may consist of nothing more than a deflector surface which is rigidly secured to the shaft inside the housing and which has a leading edge penetrating outwardly into the channel containing the liquid to be deflected inwardly.
In a second form, the deflector may take on the configuration of an annular concave disc which is rotatably mounted at its center on the shaft within the housing. In this configuration, the shaft is shaped out of axial and parallel alignment with the axis of rotation of the housing at the point where the shaft rotatably supports the disc such that the perimetral portion of the disc which is permitted to penetrate into the channel containing the liquid to be deflected is deflected inwardly by the scooping action of the concave disc edge at the points of contact therewith.
This configuration is preferable over the aforementioned deflector which is rigidly secured to the shaft, as in this configuration the concave disc is permitted to rotate with the housing and the body of liquid being centrifugally rotated therewith, thereby reducing the friction of the scooping action caused by penetration of the deflector into the rotating centrifugally formed annular band or body of liquid. In this configuration, it is preferable to provide two such discs facing each other in opposition to balance the internal deflection forces.
In addition, it may be desirable to assist the disc in its rotation by actually positively driving the same with a gear train arrangement between the rotating housing and the deflection discs.
A better understanding of the operation of these different embodiments will become more apparent with a study of the following disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages appear in the following description and claims.
The accompanying drawings show, for the purpose of exemplification without limiting the invention or the claims thereto, certain practical embodiments illustrating the principles of this invention wherein:
FIG. 1 is a simplified view in front elevation in partial section of one embodiment of the propulsion apparatus according to the present invention, as seen along line I--I of FIG. 2.
FIG. 2 is a sectional view in side elevation of the apparatus illustrated in FIG. 1 as seen along line II--II.
FIG. 3 is a simplified view in side elevation in partial section of another embodiment of the propulsion apparatus of the present invention, as seen along line III--III of FIG. 4.
FIG. 4 is a view in side elevation as seen in section along line IV--IV of FIG. 3 with the right side of the housing illustrated in FIG. 3 removed.
FIG. 5 is a simplified front view in partial section of the propulsion apparatus of the present invention similar to that illustrated in FIG. 3, and disclosing a gear power drive between the outer housing and inner deflection disc.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, the simplest embodiment of the propulsion apparatus according to the teachings of the present invention is illustrated. The propulsion apparatus consists of a closed housing 1 which is made up of three separate housing parts which join together to form the integral housing 1. These parts consist of the housing ends 2 and 3, which are joined to the center annular housing member 4 as indicated along the respective joining seams 5 and 6 which are maintained in a sealed engagement by means of machine screws 7.
Housing 1 is supported for rotation on stationary shaft 8 by means of ball bearing races 9 which is, in turn, supported at its ends by supports 10 and 11, which are secured to the object or body to be propelled or accelerated generally indicated at 12.
Within the housing 1, the deflector 13 is supported from the stationary shaft 8. The deflector 13 consists of the liquid deflection surface 14 supported by arms 15 and 16 which in turn are supported from the sleeve coupling or clamp 17, which rigidly clamps and engages stationary shaft 8 by means of clamp screws 18. If desired, in addition, clamp 17 may also be keyed to shaft 8 as indicated at 19 to prevent slippage therebetween.
The housing 1 is rotated on shaft 8 in the direction as indicated by arrow 20 in FIG. 2, by means of motor 21 rigidly mounted on support 11 which drives housing 1 through motor shaft 22 and gear 23 which meshes with gear 24 that is integral with hub 25 of the housing section 3, which in turn contains ball bearing race 9.
The motor 21 may, of course, be selected to operate from any number of different types of energy sources, such as hydraulic or electric; however, if the apparatus is to be employed in spacecraft, then it is preferable that the motor 21 be electric and operated from solar energy.
A liquid 26, preferably one of relatively high specific gravity such as mercury, is contained within housing 1 as positively illustrated in FIG. 2 and hypothetically illustrated by means of the dashed lines 27 in FIG. 1.
The housing 1 is rotated at a sufficient rate by motor 21 to centrifugally distribute the liquid 26 about the annualr channel 28 formed within the center housing portion 4 of housing 1. As a result, the liquid 26 retained in channel 28 is deflected by deflection surface 14 from the annular channel inwardly as best illustrated in FIG. 2 thereby unbalancing the otherwise balanced centrifugal forces of the centrifugally distributed liquid 26. This continuous unbalancing of the centrifugal force creates a continuous motion unilateral thrust of the entire apparatus in the direction generally indicated by arrow 30. Upon viewing the disclosure, it becomes obvious that the motion created is, in fact, continuous as opposed to being of the intermittent type disclosed by the prior art previously described.
The deflector 13 is provided with a sharp edge 31 at its forward end to reduce the frictional engagement between the deflector surface 14 and the liquid 26 as much as possible. The liquid 26 is literally scooped out of channel 28 by deflection surface 14 and directed inwardly and then permitted to return back to the channel 28 as generally indicated by the flying or sprayed liquid particles indicated at 32.
It can be seen that if one desires to change the direction of thrust of the apparatus, one need merely change the position of the deflection surface 14 relative to the rotating housing by rotating normally stationary shaft 8 to position the deflector 13 at the desired position relative to an outside reference toward which motion of the apparatus is to be directed.
Position changes of normally stationary shaft 8 are accomplished by means of the ring gear 35 which is keyed to shaft 8 and in turn may be rotated along with the shaft 8 by means of the worm gear drive 36 which is manually manipulated by means of handle 37. Worm gear drive 36 is, in turn, supported from end support 10.
Shaft 8 is received in simple sleeve bearings within supports 10 and 11 to permit these minor variations in position change for the deflector 13.
Referring next to FIGS. 3 and 4, elements in these figures which are substantially identical to those disclosed in FIGS. 1 and 2 are designated with the same reference numerals. The primary distinction between the embodiment of FIGS. 3 and 4 from the embodiment of FIGS. 1 and 2 is the type of deflector employed to scoop up or deflect the liquid inwardly from the outer annular channels where it is centrifugally retained.
In the embodiment of FIGS. 3 and 4, the deflectors 50 and 51 are in the form of opposed concave annular discs respectively, which are mounted for rotation on shaft 8 by means of roller bearings 52 received in the hub 53 of each disc. Roller bearings 52 are seated on a restricted portion 54 of shaft 8 which is a section of shaft 8 having a reduced diameter in order to confine the position of deflection discs 50 and 51 thereby preventing them from moving axially along the shaft 8.
It should be noted that the axis of rotation of deflection discs 50 and 51 are out of parallel and axial alignment with each other and also with the axis of rotation of the housing 1 such that the deflection discs 50 and 51 perimetrally converge toward each other at one point 56, which is fixed relative to shaft 8 and in addition permits the discs to penetrate into the centrifugally distributed liquid 26 along perimetral portions of the discs which pass through point 57 as illustrated in FIG. 4. When the discs 50 and 51 are disposed in this manner, they have a scooping action at their perimetral portions passing through the area of point 57 to deflect the liquid 26 inwardly toward the center of the apparatus.
The housing 1 is constructed of three parts in order to permit easy assembly and disassembly of the apparatus. The three housing parts consist of the center annular portion 58, which has more or less a triangular shaped cross-section configuration, and left and right housing ends 59 and 60, respectively, as viewed in FIG. 3. Housing sections 58, 59 and 60 are held together in a sealed relationship by means of machine screws 61 which are received in the threaded holes 62 annularly displaced about the mating machine sealing surface 63 of the central portion or section 58.
The three housing sections 58, 59 and 60, when united together in sealed engagement, provide two annular channels 28 to receive the centrifugally distributed liquid 26 therein for each deflection disc 50 and 51 respectively. In order to prevent confusion, however, the channels are numbered respectively 28' and 28". The reason two such channels are provided as opposed to one channel 28 is that in the embodiment of the FIGS. 3 and 4, two discs are employed for deflection of the liquid 26 and it is thus obvious that it is desirable to have each disc come as close to the bottom of its respective channel 28 at the place of closest association, namely, point 57, without actually engaging the interior of the rotating housing. Accordingly, the interior of the housing 1 is constructed to very closely conform to the design of discs 50 and 51 so that they may function as efficiently as possible by deflecting as much of the liquid 26 as possible from within the channels 28' and 28" inwardly between points 57 and 56. In other words, the channels 28' and 28" are tailor contoured as much as possible to the deflection discs 50 and 51 within the area wherein they protrude into the channels respectively about point 57 to assure that as much of the fluid 26 as possible is deflected inwardly by the scooping action of the discs.
While deflection discs 50 and 51 in a nonrotating condition would be effective to deflect the liquid 26 inwardly as previously described along one portion thereof in channels 28' and 28", which is selected relative to an outside reference, the reason for permitting them to free wheel in the direction indicated by arrows 64 in the same direction of the housing 1 which is indicated by arrow 20, is that this materially reduced the deflection friction encountered in a stationary deflector such as depicted in FIGS. 1 and 2. This is due to the fact that as each deflection disc 50 and 51 continually have annular perimetral portions thereof penetrating the liquid 26 which is annularly distributed by centrifugal force within channels 28' and 28" respectively, they are moving continuously with the rotating liquid body thereby decreasing the frictional resistance between the penetrating edge of the deflectors 50 and 51 and the rotating liquid body 28' and 28" which overall renders the apparatus more efficient than that disclosed in FIGS. 1 and 2.
In all other respects, the embodiment of FIGS. 3 and 4 functions identically to the embodiment of FIGS. 1 and 2, with the result that the unbalanced centrifugal force created by the deflector discs 50 and 51 penetrating into the mating contoured channels 28' and 28" create a resultant thrust generally in the direction indicated by arrow 30 in FIG. 4, which would be approximately a thrust away from the viewer of FIG. 3.
As with the embodiment of FIGS. 1 and 2, the direction of unilateral thrust of the embodiment disclosed in FIGS. 3 and 4 may be varied by rotating shaft 8 as required to change the direction of travel of the apparatus as desired within a 360° possibility.
In both FIGS. 3 and 4, the liquid 26 is illustrated only in dashed outline form in order to prevent confusion in the FIGS. by covering up other portions of the structure with the liquid. However, the liquid 26 which is scooped up by the concave interior of deflection discs 50 and 51 is illustrated in FIG. 4 in positive form as centrifugally dislodging itself therefrom in the form of a spray as indicated at 32 similar to that shown in FIG. 2 in order to provide a more vivid image of how the apparatus functions.
The embodiment of FIGS. 3 and 4 is provided with substantially the same mechanism for turning shaft 8 for changing the direction of thrust of the overall apparatus wherein a ring gear 35 is meshed with a worm gear 36, which may be manipulated by handle or lever 37. It is, of course, obvious that this mechanism may be manipulated automatically by any suitable motor means which may, in turn, if desired, be operated through computerized control techniques.
As will be obvious to those of ordinary skill in the art, the continual frictional engagement between the deflection discs 50 and 51, for that matter between the deflector 13 and the liquid 26 in the structure of FIGS. 1 and 2, will create considerable heat, and particularly so where no atmosphere is encountered such as in space, due to the fact that the atmosphere is not present to assist in dissipating the heat thereby created and conducted through the walls of the housing 1 of the apparatus.
In this situation, it is desirable to continually withdraw, cool, and recirculate the working liquid 26. To accomplish this, the embodiment of FIGS. 3 and 4 is provided with a liquid recirculating system consisting of the withdrawal tube or line 70, which has pronged extensions 71 and 72 that extend downwardly into channels 28' and 28" respectively, and have their openings exposed to the onward rushing fluid 26 such that a portion of the liquid 26 is forced into the withdrawal line 70 which passes on out through the right side of shaft 8 as indicated in FIG. 3, to a cooling unit (not shown), whereupon it is returned through return or refill line 73, seen at the left of FIG. 3 through the center of shaft 8, where it is permitted to exit as indicated at 74 back into annular channels 28' and 28".
Rather than scooping up the liquid to be cooled by penetrating the withdrawal tubes 71 and 72 directly into the rotating body of fluid 26 as indicated in FIG. 4, the withdrawal tube 70 may also be situated such that it withdraws a portion of the fluid from the spray or stream of liquid 32 being thrown off of discs 50 and 51 as indicated at 70'.
Tubes 71, 72 and 73 may also be utilized to regulate the desired depth of liquid body 26.
While it is obvious that one deflection disc 50 or 51 may be employed without the use of the other to obtain the unbalanced centrifugal force required to drive the apparatus, it is always preferable to use two such deflection discs in opposition in order to balance the deflection forces so that additional unbalanced forces are not applied to the system which will unpredictably affect its travel characteristics.
In addition, it is desirable that the quantity of liquid 26 contained in annular channels 28' and 28" be equal at all times in order to maintain the apparatus in a balanced condition of operation. This is accomplished by passages 65 which communicate the channels with each other so that the fluid body in both channels will seek a common level.
In addition, it is also desirable to employ the apparatus of the present invention such as disclosed in the embodiment of FIGS. 1 and 2 or in the embodiment of FIGS. 3 and 4 in duplicate, with the duplicate apparatus being rotated in a direction opposite that of the original and in close proximity thereto so that the torque effect imparted by each apparatus counteracts that of the other, thereby providing true unilateral motion. In this manner, the effects of torque may be ignored for all practical purposes.
As opposed to permitting the deflection discs 50 and 51 to rotate freely about shaft 8 as disclosed in the embodiment of FIGS. 3 and 4, it may be desirable to positively drive the discs in order to further reduce the frictional engagement between the liquid being deflected and the deflection discs. One method of positively driving the discs 50 and 51 is illustrated in FIG. 5, wherein like elements are designated with the same reference numerals. The structure of FIG. 5 is, for all practical purposes, identical to that of FIGS. 3 and 4, with the exception that the discs 50 and 51 are positively driven through the rotation of housing 1 by means of the planetary gear train 90 which consists of a ring gear 81 which is rigidly secured to the inside wall of housing section 59 as indicated at 82, gear 83 which is meshed with gear 81, and secured to shaft 84, which is in turn rigidly and coaxially secured to gear 85 which is meshed with ring gear 86. Ring gear 86 is rigidly secured to disc 50 as indicated at 87, Shaft 84 which connects gears 83 and 85 for rotation, is rotatably received in block 88 with antifriction bearings 89. Block 88 is, in turn, rigidly secured to shaft 8 as indicated at 80.
Accordingly, when housing 1 rotates about shaft 8, gears 83 and 85 are also caused to rotate thereby causing ring gear 86 together with deflection disc 50 to rotate in the same direction as housing 1. The ratio of the gears may also obviously be selected to rotate disc 51 at the desired speed, which generally will be a speed which permits the inside of the housing 1 and the perimetral edge of the disc to rotate at the same rate at point 57, as indicated in FIG. 4. This accordingly insures minimal friction between the deflectors and the rotating liquid mass. | A continuous motion propulsion apparatus wherein a quantity of liquid is rotated within an annular housing to centrifugally distribute the liquid thereabout in an annular channel. A deflection device is mounted within the housing and deflects the liquid inwardly from the annular channel at a predetermined position relative to an outside reference thereby creating an unbalanced centrifugal force which unidirectionally propels the apparatus with continuous motion. |
The present U.S. Patent Application is a Division of U.S. patent application Ser. No. 13/603,761 filed on Sep. 5, 2012, which is a Division of U.S. patent application Ser. No. 12/823,316 filed on Jun. 25, 2010, and issued as U.S. Pat. No. 8,325,490 on Dec. 4, 2012, which is a Division of U.S. patent application Ser. No. 12/015,543 filed on Jan. 17, 2008 and issued as U.S. Pat. No. 7,821,796 on Oct. 26, 2010. The present U.S. Patent Application is also related to U.S. patent application Ser. No. 11/751,786 entitled “MULTI-LAYER CIRCUIT SUBSTRATE AND METHOD HAVING IMPROVED TRANSMISSION LINE INTEGRITY AND INCREASED ROUTING DENSITY”, filed on May 22, 2007 by the same inventors and assigned to the same Assignee, and issued as U.S. Pat. No. 7,646,082 on Jan. 12, 2010. The disclosures of the above-referenced U.S. Patent Applications are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to integrated circuit internal package interconnects, and more particularly, to a methodology and multi-layer substrate that has improved signal integrity and impedance matching.
2. Description of the Related Art
High-density interconnect schemes for processor packages, as well as other very-large-scale integrated (VLSI) circuits typically use a large number of circuit layers to connect one or more dies to electrical terminals disposed on one or more surfaces of the package, as well as to interconnect multiple dies in multi-die packages.
A typical stack-up for a present-day VLSI circuit substrate is fabricated in very thin layers on one or both sides of a rigid core that provides stiffness and stability to integrated circuit substrates, which may then be encapsulated after dies are attached. The core typically includes pass-through vias that have a larger diameter than the vias used between the thin circuit layers and that pass between thin insulating layers. For example, in a substrate having a core 800 μm thick, the diameter of the through vias may be 500 μm in diameter, while the outer layer interconnects may have vias only 50 μm in diameter. The reason for the larger diameter holes through the core is the relative thickness of the core, which makes reliable fabrication and resin/conductive filling of the vias more difficult than for vias between the thin insulating layers in the outer circuit layers that are laminated on the core.
Since the interconnect routing density directly determines the required size of the final package, routing resources are critical in an integrated circuit package and space is at a premium. However, for critical signal paths such as clock and high-speed logic signal distribution, transmission lines must be maintained throughout the signal path in order to prevent signal degradation. Therefore, a reference voltage plane (e.g., ground) metal layer is provided on the surface of the core, with voids around the via and interconnect areas at the surface(s) of the core so that a transmission line is provided for the next signal layer above/below the core surface metal layer(s). As a result, signal path conductors must be routed around the large diameter vias passing through the core which are not connected to the metal layer. Further, the signal path conductors must also be routed away from discontinuities in the metal layers(s) caused by the voids through which the vias pass, since the lack of reference voltage plane metal will cause a change in impedance of the transmission line. Therefore, the number of signal routing channels is severely limited by the presence of the large-diameter vias that extend through the core that provide signal paths, and the large-diameter vias that provide voltage planes other than the voltage plane connected to the core surface metal layer.
The above-incorporated U.S. Patent Application provides additional routing channels by providing continuous reference plane metal adjacent to conductive signal paths, and frees additional signal routing channels over reference voltage vias by providing reference plane metal between the ends of the vias and any signal paths routed above or below the via ends. Disruption of signals carried by signal-bearing vias is avoided by providing voids in the reference plane metal above or below the ends of the signal-bearing vias. However, in such designs, routing is still critically limited by the inability to route signal paths over the signal-bearing vias.
It is therefore desirable to provide a multi-layer integrated circuit, substrate and method that maintain signal integrity and impedance matching in an integrated circuit package while providing an increased amount of signal routing channels, including channels routed over signal-bearing vias.
BRIEF SUMMARY OF THE INVENTION
The objective of improving signal integrity and impedance matching in a multi-layer integrated circuit substrate while permitting routing over signal bearing vias is provided in an integrated circuit substrate, and methods for making and designing the integrated circuit substrate.
The substrate includes a core having large diameter vias and at least one signal layer having signal conductors having a width substantially smaller than the diameter of the large diameter vias. The signal conductors are connected to large diameter vias by a small diameter portion passing through a first insulating layer disposed between the core and a transmission line reference plane metal layer, and a second insulating layer disposed between the transmission line reference plane metal layer and the signal layer.
The transmission line reference plane metal layer defines voids having an area larger than the area of signal-bearing large diameter vias, so that the presence of the transmission line reference plane metal layer does not cause substantial insertion capacitance with respect to critical signals. For signal-bearing vias over which critical signal paths are routed, a conductive stripe extends across the voids to isolate the critical signal conductive paths from the ends of the signal-bearing vias. The width of the stripes may be equal to the width of the critical signal conductive paths, or the width may be determined by the relative criticality of the signals. The more critical the signal borne by the conductive path is to the signal borne by the conductive via, the wider the stripe and vice-versa.
The foregoing and other objectives, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiment of the invention, as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein like reference numerals indicate like components, and:
FIG. 1A is a cross-sectional view of a substrate in accordance with an embodiment of the present invention.
FIG. 1B is top view of the substrate of FIG. 1A .
FIGS. 2A-2G are cross sectional views illustrating steps in the manufacture of a substrate in accordance with an embodiment of the present invention.
FIG. 2H is a cross sectional view of an integrated circuit package in accordance with an embodiment of the present invention.
FIG. 3 is a graph depicting a reflectometer display depicting a performance improvement provided by the substrate of the present invention.
FIG. 4 is a graph depicting a reflectometer display depicting the effect of conductive strips of the substrate of the present invention on signal-bearing via performance.
FIG. 5 is a pictorial diagram depicting a workstation computer system by which design methods and computer program products are executed in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention concerns integrated circuit package substrates and methods of designing and making the substrates provide for routing of conductive signal paths over signal-bearing vias, while solving impedance matching and isolation problems associated with prior art substrates. As in the above-incorporated U.S. Patent Application “MULTI-LAYER CIRCUIT SUBSTRATE AND METHOD HAVING IMPROVED TRANSMISSION LINE INTEGRITY AND INCREASED ROUTING DENSITY”, metal reference planes are used to provide transmission line characteristics for signal paths and voids are included in the metal reference planes over signal-bearing vias to prevent insertion capacitance mismatches. However, in the present invention, voids over which conductive signal paths are routed include conductive “stripes” extending across the vias in line with the conductive signal path, effectively splitting the voids into two voids (or more if multiple signal paths are routed over the via, as a strip could be provided for each signal path). The stripes also reduce cross-coupling between the signal path and the via, as the fields associated with the signal path are more contained due to the presence of the stripe.
The stripe width is generally equal to that of the conductive signal path, but may be altered to reduce fringing effects on impedance or may be tailored to the relative criticality of the individual signals on the via and the conductive signal path. Since the ideal condition for proper impedance matching along the conductive signal path is the absence of any void at all, and the ideal condition for eliminating insertion capacitance at the ends of the void is the absence of the metal reference plane (or at least a complete void), the present invention involves a trade-off between preserving the signal on the conductive signal path and preserving the signal on the signal-bearing via. Therefore, since the width of the stripe is proportional to the performance of one signal and inversely proportional to the other signal, the relative criticality of the signals can be used to determine the appropriate width.
The stripe is also generally centered in the void (or, in other terms, between the two partial voids formed by splitting the void), but that is not a limitation of the present invention. Signal routing considerations may require an offset from a central diameter of the void, or the direction of the signal path and stripe may change as the signal crosses the void. In general, the shape and position of the stripe may reflect any shape and position of the conductive signal path in order to maintain a level of impedance matching that is improved over the performance obtainable in the absence of the stripe.
Referring now to FIG. 1A , an integrated circuit package substrate in accordance with an embodiment of the present invention is shown. The substrate includes a core 10 including through-via conductors provided by resin-filled plated-through hole (RFPs) 12 A- 12 C. Metal layers are formed by plating, deposition or laminating on both sides of core 10 containing jog stubs 14 A- 14 C and areas of reference voltage plane layer 11 , with an insulating layer 15 laminated above stubs 14 A- 14 C and reference voltage plane layer 11 . A transmission line reference plane metal layer 17 is laminated, or otherwise deposited, above insulating layer 15 and a second insulating layer 19 is laminated, or otherwise deposited, above transmission line reference plane metal layer 17 . A signal layer including signal path conductors 18 is laminated or otherwise deposited above insulating layer 19 . For each critical signal-bearing RFP 12 A, large-diameter voids 13 in transmission line reference plane metal layers 17 are provided above and below ends of signal-bearing RFPs 12 A, which reduces the shunt capacitance from signal-bearing RFP 12 A to transmission line reference plane metal layers 17 . In the present invention, a stripe 20 extends across the void 13 above signal-bearing RFP 12 A, which provides some shunt (insertion) capacitance, as mentioned above. However, stripe 20 reduces coupling between a signal path conductor 18 A that is routed above signal-bearing RFP 12 A, and further provides a much-improved impedance profile to signal path conductor 18 A. While the void portions surrounding stripe 20 are devoid of metal, in practice, the void portions will generally be filled with dielectric, lamination adhesive or other non-conductive material.
Signal-bearing RFPs 12 A are connected to signal path conductors 18 by stubs 14 A and small-diameter vias 16 A. Without large diameter voids 13 , the shunt capacitance from the ends of signal-bearing RFP 12 A to transmission line reference plane metal layers 17 will cause signal degradation greater than that caused by the presence of stripe 20 . Voltage plane RFPs 12 B and 12 C (and optionally RFPs bearing non-critical signals) have no corresponding large-diameter voids in transmission line reference plane metal layer 17 , which increases their distributed capacitance by the shunt capacitance from RFPs 12 B, 12 C to transmission line reference plane metal layer 17 , which is generally desirable. Therefore, the stripes of the present invention are generally used over signal-bearing vias, and generally only when a conductive signal path is routed over a signal-bearing via.
Reference plane RFP 12 B, which corresponds to the voltage plane to which transmission line reference plane metal layer 17 is connected, has a stub 14 B connecting to transmission line reference plane metal layer 17 through a small via 16 B. Blind vias connected to transmission line reference plane metal layer 17 can further be used in connections to signal path layers added above the layer containing signal conductors 18 , to provide electrical connection to the particular voltage plane connected to transmission line reference plane metal layer 17 , if needed. Therefore, no void (and therefore, no stripe) is needed in transmission line reference plane metal layer 17 above reference plane RFP 12 B. Other voltage plane RFPs 12 C will generally require formation of vias 16 C extending to other layers above transmission line reference plane metal layer 17 from stubs 14 C. Small-diameter voids 13 A provide connection to other voltage plane RFPs 12 C and extend only above the ends of stubs 14 C, for signal routing channels above transmission line reference plane metal layer 17 above the top ends (and beneath the bottom ends for layers applied beneath core 10 , not specifically shown) of other voltage plane RFPs 12 C. The voltage plane used to provide a reference to transmission line reference plane metal layer 17 may be a power supply voltage supplying the input/output drivers (the I/O signal reference and/or return voltage) or ground.
Referring now to FIG. 1B , a top view of the integrated circuit package substrate of FIG. 1A is shown. Voids 13 are defined by transmission line reference plane metal layer 17 , with additional metal removed above signal path stubs 14 A and small diameter voids 13 A for vias 16 A that connect signal path stubs 14 A to other signal layers. The resulting integrated circuit package substrate has improved isolation between signal path conductors 18 routed over the continuous portions of transmission line reference plane metal layer 17 , while eliminating the shunt capacitance from signal-bearing RFPs 12 A to metal layer 17 , when no stripe is present and reducing the shunt capacitance when a stripe is present. Large diameter via 12 A is illustrated with a conductive signal path 18 A routed above and a stripe 20 included in void 13 B. Stripe 20 has been widened slightly for illustrative purposes, and another strip 20 A is shown without a corresponding conductive path or via for clarity.
Thus, in the present invention increased routing channels are provided in the regions extending over the top ends (or bottom ends) of all of RFPs 12 A, 12 B and 12 C. Thus, the substrate of the present invention provides improved signal performance in signal paths, providing for higher processor or other VLSI circuit operating frequencies, while providing increased routing flexibility by providing more routing channels that can have adequate signal performance no matter whether signal paths are routed above core RFPs that carry power distribution and/or non-critical signals as described in the above-incorporated U.S. Patent Application, or routed above signal bearing RFPs such as RFP 12 A.
Referring now to FIGS. 2A-2G , a method of making an integrated circuit substrate and integrated circuit in accordance with an embodiment of the invention is shown. As shown in FIG. 2A , starting from a core dielectric layer 40 having via holes 41 formed therein, holes 41 are filled with resin/metal to form PTHs 42 . Stubs 44 and reference plane areas 43 are formed on both surfaces of core 40 , as shown in FIG. 2B . An insulating layer 45 is then applied to one or both sides of the core dielectric layer 40 , over stubs 44 as shown in FIG. 2C . Next, insulating layer 45 is opened to generate small-diameter via holes, forming insulating layer 55 . Then, metal is added in the small-diameter via holes to form small vias 56 to connect to voltage plane RFPs as shown in FIG. 2D . Next, a transmission line reference plane metal layer 58 with voids 57 and stripes 58 A- 58 C is applied as shown in FIG. 2E . Stripes 58 A and 58 C illustrate stripe for conductive paths extending perpendicular to the page of the Figure, and stripe 58 B illustrates a stripe for a conductive path extending along the plane of the Figure. Voids 57 , including the void portions around stripes 58 A- 58 C will generally be filled with dielectric insulating material or lamination adhesive as described above. Both the insulating layer 55 and transmission line reference plane metal layer 58 may be applied as laminates, or the insulating layer may be deposited and/or transmission line reference plane metal layer 58 may be plated atop insulating layer 55 . Voids 57 and stripes 58 A- 58 C may be pre-formed in transmission line reference plane metal layer 58 or etched. Next, as shown in FIG. 2F , another insulating layer 60 is applied in a manner similar to that for insulating layer 55 , and small voids 62 are formed or pre-formed in insulating layer 60 for connection to signal RFPs. Finally, blind vias 64 and a signal layer 66 are formed as shown in FIG. 2G that provide electrical connection to signal RFPs. Conductive signal path 66 A corresponding to stripe 58 A, conductive signal path 66 B corresponding to stripe 58 B and conductive signal path 66 C corresponding to stripe 58 C are also shown, which form part of signal layer 66 . Blind vias 64 and signal layer 66 may be formed at the same time, for example, by plating, or blind vias 64 may be formed first by filling or plating and then signal layer 66 laminated or plated to connect to blind vias 64 .
Referring now to FIG. 2H , an integrated circuit in accordance with an embodiment of the present invention is shown. The substrate of FIG. 2G is further modified by adding further signal layers, and optionally voltage plane layers on one or both sides of the core dielectric layer 40 . As illustrated another insulating layer 55 A and signal layer 76 A are added, but in practice, numerous other layers may be added. A semiconductor die 70 is attached to lands or other structures accessible from the top layer of the substrate shown in FIG. 2G and terminals or lands (not shown) may similarly be added to the bottom side of the substrate after other circuit layers are added. Alternatively, lands can be formed directly on the bottom side of core dielectric layer 40 or terminals may be attached to the bottom side of RFPs 42 .
Referring now to FIG. 3 and FIG. 4 , performance benefits and trade-offs of the present invention are shown. FIG. 3 illustrates a reflection trace 80 A representing performance of a 28 μm wide conductive signal path routed over a via that is 150 μm in diameter and including a 28 μm wide stripe under the conductive signal path. An improvement of 3 dB at 10 GHz is shown (in reduction of reflection) over reflection trace 80 B, which is for the same configuration without the stripe. However, as mentioned above, including the stripe changes the performance of the signal-bearing via. FIG. 4 illustrates a reflection trace 82 A for the configuration including the stripe, which is approximately 3 dB higher in reflection at 10 GHz for the configuration without the stripe, which is illustrated by reflection trace 82 B. However, as is noted from the Figures, the effect of the void/via on performance of the signal path routed over the via is greater than the effect of the stripe on the performance of the signal path that includes the via. Therefore, absolute reflection level and improvement should be taken into account in any design, as well as optionally the relative criticality of the signals.
Referring now to FIG. 5 , a workstation computer system 100 is shown in which the methods of the present invention are carried out in accordance with an embodiment of the present invention, according to program instructions that may be embodied in a computer program product in accordance with a present invention, for example program instructions stored on a CD-ROM disc CD. Workstation computer system includes a processor 102 for executing the program instructions coupled to a memory 104 for storing the program instructions, data and results used in designing integrated circuit substrates in accordance with embodiments of the present invention. Workstation computer system 100 also includes peripheral devices such as CD-ROM drive 105 for reading discs such as CD in order to load the program instructions into workstation computer 100 . Input devices, such as a keyboard 107 A and a mouse 107 B are coupled to workstation computer system 100 for receiving user input. A graphical display 106 for displaying results such as the layout of metal layer 17 of FIGS. 1A-1B , substrate layer designs as illustrated in FIGS. 2A-2G and test data or simulations such as that of FIGS. 3-4 . The depicted workstation computer 100 is only exemplary and illustrates one type of computer system and arrangement suitable for carrying out the design methods of the present invention. The design methods generally identify the locations of signal bearing vias and generate a mask design for a transmission line reference plane metal layer that includes voids around the profile of the signal-bearing vias so that capacitive coupling between the ends of the signal-bearing vias and the transmission line reference plane metal layer is substantially reduced. The locations of conductive signal paths routed over the signal-bearing vias is also identified and stripes inserted to reduce coupling and match impedance of the conductive signal path. The design methods may also consider the relative criticality of signals on the signal-bearing voids and conductive signal path and adjust the width of the stripes to optimize trade-offs in performance.
While the invention has been particularly shown and described with reference to the preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form, and details may be made therein without departing from the spirit and scope of the invention. | Manufacturing circuits with reference plane voids over vias with a strip segment interconnect permits routing critical signal paths over vias, while increasing via insertion capacitance only slightly. The transmission line reference plane defines voids above (or below) signal-bearing plated-through holes (PTHs) that pass through a rigid substrate core, so that the signals are not degraded by an impedance mismatch that would otherwise be caused by shunt capacitance from the top (or bottom) of the signal-bearing PTHs to the transmission line reference plane. In order to provide increased routing density, signal paths are routed over the voids, but disruption of the signal paths by the voids is prevented by including a conductive strip through the voids that reduces the coupling to the signal-bearing PTHs and maintains the impedance of the signal path conductor. |
This application is a divisional of application Ser. No. 07/691,191, filed on Apr. 26, 1991, now U.S. Pat. No. 5,328,990, the entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The lymphokine, Macrophage Migration Inhibition Factor (MIF), has been identified as a mediator of the function of macrophages in host defence and its expression correlates with delayed hypersensitivity and cellular immunity. A 12,000 da protein with MIF activity was identified by Weiser et al, Proc. Natl. Acad. Sci. U.S.A., 86, 7522-7526 (1989). MIF was first characterized by expression cloning from activated human T-cells, however, the abundance of the product is low in these cells. No MIF protein is commercially available, although the human cDNA is marketed by R&D Systems Inc., Minneapolis, Minn.
The eye lens contains high concentrations of soluble proteins, Harding et al, The Eye, ed. Davson, H., Academic Press, New York, Vol. 1B, pp. 207-492; Wistow et al, Ann. Rev. Biochem., 57, 479-504 (1988); and Wistow et al, Nature, 326, 622-624 (1987). The most abundant proteins, the crystallins, are structural, comprising the refractive material of the tissue. Some crystallins are specialized for the lens, others are identical to enzymes expressed in lower amounts in other tissues. Individual crystallins may account for a quarter or more of total lens protein, Wistow et al, Nature, 326, 622-624 (1987) and Wistow et al, PNAS, 87, 6277-6280 (1990). However, other proteins are also present at moderate abundance, typically in the range 0.1-1% of total protein. Some of these are also enzymes, such as α-enolase or aldehyde dehydrogenase, found as crystallins in some species, Wistow et al, J. Mol. Evol., 32, 262-269 (1991).
SUMMARY OF THE INVENTION
It has been discovered that a moderately abundant protein in the eye lens, "10K protein", which accounts for as much as 1% of total protein in young or embryonic lenses is similar to MIF. An equivalent protein is present in all lenses examined, including bovine lenses from slaughtered animals. Accordingly, eye lenses of various animals, especially birds and mammals, can be used as a source of MIF.
MIF is extremely abundant in lens compared with other known sources. Proteins accumulate to high levels in lens, which has low proteolytic activity. Lenses may be removed from eyes quickly and simply with one incision. Moreover, no other abundant lens proteins are close to lens MIF in size, thus facilitating its separation. Lenses can similarly be used as abundant sources of active enzymes including lactate dehydrogenase B and argininosuccinate lyase.
The lens MIF can be obtained by homogenizing ocular lens to form a homogenate, separating a soluble extract and an insoluble membrane fraction from said homogenate and recovering purified MIF from said soluble extract.
The present invention is also directed to purified lens MIF. In preparing the purified natural lens MIF of the present invention, a stimulant such as Con-A is not added to the preparation and therefore this possible source of contamination is avoided.
MIF plays an important role in the inflammatory response. Lenses could become a useful source of MIF protein for research and therapeutic purposes. In lens, MIF expression is associated with cell differentiation and with expression of the proto-oncogene N-myc. Lens MIF may be a growth factor in addition to its role as a lymphokine. Like other lymphokines, such as IL-2, MIF could have specific therapeutic value in stimulation of immune system and other cells. In particular, lens MIF may play a role in some inflammatory conditions in the eye. MIF isolated from lens could be modified to derive antagonists for the inflammatory process.
The MIF of the present invention can be produced by recombinant DNA techniques. The invention therefore is also directed to recombinant DNA which encodes MIF, replicable expression vectors which contain the DNA and which can express MIF and transformed cells and/or microorganisms which contain the DNA and which can express large amounts of MIF.
DETAILED DESCRIPTION OF THE INVENTION
The MIF can be separated from the lens by a variety of different procedures.
As a first step, the lens should be homogenized in an aqueous solution, preferably an aqueous buffered solution having a pH of about 7 to 7.6, preferably 7 to 7.4 which does not adversely affect the MIF, in order to allow the soluble materials to dissolve in the buffer. The buffered solution will usually not contain any other solvents. Homogenization is preferably achieved by physically breaking up the lenses by use of a glass rod, blender or other suitable devices or procedures. The volume ratio of lens to the solution is usually 1:1 to 5, preferably 1:1.5 to 3 (v/v).
After the lens is homogenized, the insoluble membranes are separated from the aqueous solution containing the soluble extract. This can be accomplished in any known manner but centrifugation appears to be especially useful.
The MIF is then recovered from the soluble extract. In the experiments reported herein, this is accomplished by subjecting the soluble extract to sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). However, if it is desired to separate the MIF from the soluble extract on a larger scale, various procedures such as column chromatography (sizing columns) and/or isoelectric focusing can be utilized.
All lenses examined by SDS polyacrylamide gel electrophoresis have a prominent minor band with subunit size around 10-12 kDa, "10K protein". MIF is the major component in the 10-12,000 da subunit size range, as visualized by SDS polyacrylamide gel electrophoresis. In aged and cataractous lenses, fragments of α-crystallin have been found in this size range, Harding et al, The Eye, ed. Davson, H. (Academic Press, New York), Vol. 1B, pp. 207-492 (1984). However, even embryonic lenses, in which proteolysis is unlikely to have occurred to a great extent, have a distinct 10K subunit band. This band was isolated from embryonic chick lens and sequenced. Surprisingly, the sequence obtained showed close identity to a recently described lymphokine, human MIF, Weiser et al, Proc. Natl. Acad. Sci. U.S.A., 86, 7522-7526 (1989). The polymerase chain reaction (PCR) was used to clone the mRNA for chick lens 10K protein. This provided a probe to clone cDNA for chick and three week old mouse lens 10K protein. PCR was also used to clone 10K protein from fetal human lens.
The presence of MIF at high levels in lens suggests it may have a wide role as a polypeptide growth factor rather than a restricted function as a lymphokine. Preliminary experiments using PCR suggest that MIF in embryonic chick lens is expressed in equatorial and fiber cells but not in central epithelium, consistent with a role in the differentiation of lens cells. Northern blot analysis with the cDNA for mouse lens 10K/MIF shows that the message is present in various tissues, including lens, brain and kidney.
The present invention is also directed to a vector comprising a replicable vector and a DNA sequence encoding the MIF inserted into the vector. The vector may be an expression vector and is conveniently a plasmid.
The MIF preferably comprises one of the sequences described in the SEQUENCE LISTING or a homologous variant of said MIF having 5 or less conservative amino acid changes, preferably 3 or less conservative amino acid changes. In this context, "conservative amino acid changes" are substitutions of one amino acid by another amino acid wherein the charge and polarity of the two amino acids are not fundamentally different. Amino acids can be divided into the following four groups: (1) acidic amino acids, (2) neutral polar amino acids, (3) neutral non-polar amino acids and (4) basic amino acids. Conservative amino acid changes can be made by substituting one amino acid within a group by another amino acid within the same group. Representative amino acids within these groups include, but are not limited to, (1) acidic amino acids such as aspartic acid and glutamic acid, (2) neutral polar amino acids such as valine, isoleucine and leucine, (3) neutral non-polar amino acids such as asparganine and glutamine and (4) basic amino acids such as lysine, arginine and histidine.
In addition to the above mentioned substitutions, the MIF of the present invention may comprise the specific amino acid sequences shown in the SEQUENCE LISTING and additional sequences at the N-terminal end, C-terminal end or in the middle thereof. The "gene" or nucleotide sequence may have similar substitutions which allow it to code for the corresponding MIF.
In processes for the synthesis of the MIF, DNA which encodes the MIF is ligated into a replicable (reproducible) vector, the vector is used to transform host cells, and the MIF is recovered from the culture. The host cells for the above-described vectors include prokaryotic microorganisms including gram-negative bacteria such as E. coli, gram-positive bacteria, and eukaryotic cells such as yeast and mammalian cells. Suitable replicable vectors will be selected depending upon the particular host cell chosen. Alternatively, the DNA can be incorporated into the chromosomes of the eukaryotic cells for expression by known techniques. Thus, the present invention is also directed to recombinant DNA, recombinant expression vectors and transformed cells which are capable of expressing MIF.
For pharmaceutical uses, the MIF is purified, preferably to homogeneity, and then mixed with a compatible pharmaceutically acceptable carrier or diluent. The pharmaceutically acceptable carrier can be a solid or liquid carrier depending upon the desired mode of administration to a patient. If the MIF is used to stimulate growth or differentiation of cells, specifically mammalian or bird cells, the MIF is contacted with the cells under conditions which allow the MIF to stimulate growth or differentiation of the cells. MIF could be administered to stimulate macrophages, which might be useful under some circumstances. For suppression of inflammation, macrophages would need to be unstimulated, this might be achievable using modified MIF as an antagonist.
EXAMPLE 1
Lenses:
Chick lenses were excised from 11 day post fertilization embryos. Mouse lenses were from 3 week old BALB/C mice. Human fetal lenses were from a 13.5 week fetus obtained in therapeutic abortion in 1986 and saved at -80° C. Bovine lenses were obtained from approximately 1 year-old animals from slaughter.
Lens Protein:
For protein analysis, lenses were homogenized with a Teflon tipped rod in Eppendorf tubes (1.5 ml) in TE buffer (10 mM Tris-HCl, pH 7.3; 1 mM EDTA) in an amount of about 1:2 (v/v). Membranes were spun down by microcentrifugation and the soluble extract retained. Proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, using 15% acrylamide, 1% SDS, Laemmli, Nature, 227, 680-685 (1970). Loading buffer contained 1 mM mercaptoethanol. For sequencing, gels were electroblotted onto nitrocellulose. The 10K band was excised. The Harvard Microchemistry facility performed microsequencing as a service, as described before, Wistow et al, J. Cell Biol., 107, 2729-2736 (1988). The protein was digested off the nitrocellulose by trypsin. Peptides were separated by HPLC and the major peaks sequenced using an Applied Biosystems automated sequencer. An initial N-terminal sequence was obtained by direct microsequencing of a fragment eluted from a coomassie blue stained gel slice.
Computer analysis:
Sequences were compared with the translated GenBank database, v65 using the SEQFT program of the IDEAS package, Kanehisa, IDEAS User's Manual (Frederick Cancer Research Facility, Frederick, Md.) (1986), run on the CRAY XMP at the Advanced Scientific Computing Laboratory, Frederick, Md.
RNA Preparation and Analysis:
Chick, mouse and human lenses and other tissues were homogenized in RNAzol (Cinna/Biotecx, Friendswood, Tex.) and subjected to RNA extraction, Chomczynski et al, Anal. Biochem., 162, 156-159 (1987). RNA was quantitated by UV absorption. For Northern blots, equal amounts of RNA were run on formaldehyde gels, Davis et al, Basic Methods in Molecular Biology, Elsevier Science Publishing Co., New York, N.Y. (1986) and electroblotted onto nitrocellulose or nylon membranes, Towbin et al, Proc. Natl. Acad. Sci. U.S.A., 76, 4350-4354 (1979).
PCR:
Oligonucleotides were designed from the sequence of chick lens 10K protein peptides and from the sequence of human MIF. Bam HI and Sal I sites were incorporated as shown.
oligo sequences: ##STR1##
Chick and human lens RNA were amplified using one step of the reverse transcriptase reaction primed with either 3' or oligo dT primers, Innis et al, PCR Protocols, A Guide to Methods and Applications, Academic Press, Inc., New York, N.Y., 1st Ed. (1990). First strand cDNA was then amplified by 30 cycles of PCR using an annealing temperature of 55° C. Product was visualized using 1% agarose gels and ethidium bromide staining.
cDNA cloning and Sequencing:
The 300 bp chick lens cDNA PCR product was subcloned in Bluescript II (Stratagene, La Jolla, Calif.) following digestion with Bam HI and Sal I. A Bam HI site in the chick sequence resulted in two fragments which were cloned separately. Multiple clones were sequenced using Sequenase reagents (USB, Cleveland, Ohio) and 35 S-dATP label (Amersham, Arlington Hts., Ill.). The human lens PCR product was subcloned as a single Bam HI-Sal I fragment and sequenced. The chick PCR product was also used as a probe by labelling with 32 P-dCTP and random priming using a kit from Bethesda Research Laboratory, Gaithersburg, Md. This was used to screen an embryonic chick lens cDNA library in λgt11 (Clontech, Palo Alto, Calif.) and a newborn mouse lens library in λzap (vector from Stratagene, library a gift from Joan McDermott, NEI). Clones were screened, purified and sequenced by standard methods, Davis et al, Basic Methods in Molecular Biology, Elsevier Science Publishing Co., New York, N.Y. (1986).
The partial cDNA sequences obtained are as follows:
__________________________________________________________________________human lens MIF from PCR (SEQ. ID. NO. 1)CGTGCCCCGCGCCTCCGTGCCGGACGGGTTCCTCTCCGAGCTCACCCAGCAGCTGGCGCAGGCCACCGGCAAGCCCCCCCAGTACATCGCGGTGCACGTGGTCCCGGACCAGCTCATGGCCTTCGGCGGCTCCAGCGAGCCGTGCGCGCTCTGCAGCCTGCACAGCATCGGCAAGATCGGCGGCGCGCAGAACCGCTCCTACAGCAAGCTGCTGTGCGGCCTGCTGGCCGAGCGCCTGCGCATCAGCCCGGACAGGGTCTACATCAACTATTACGACATGAACGCGGCCAATGTGmouse lens MIF from cDNA (SEQ. ID. NO. 3)GTGAACACCA ATGTTCCCCG CGCCTCCGTG CCAGAGGGGTTTCTGTCGGA GCTCACCCAG CAGCTGGCGC AGGCCACCGGCAAGCCCGCA CAGTACATCG CAGTGCACGT GGTCCCGGACCAGCTCATGA CTTTTAGCGG CACGAACGAT CCCTGCGCCCTCTGCAGCCT GCACAGCATC GGCAAGATCG GTGGTGCCCAGAACCGCAAC TACAGTAAGC TGCTGTGTGG CCTGCTGTCCGATCGCCTGC ACATCAGCCC GGACCGGGTC TACATCAACTATTACGACAT GAACGCTGCC AACGTGGGCT GGAACGGTTCCACCTTCGCT TGAGTCCTGG CCCCACTTAC CTGCACCGCTGTTCTTTGAG CCTCGCTCCA CGTAGTGTTC TGTGTTTATCCACCGGTAGC GATGCCCACC TTCCAGCCGG GAGAAATAAATGGTTTATAA GAG AAAAAAchick lens MIF (SEQ. ID. NO. 5)CGTCTGCAAGGACGCCGTGCCCGACAGCCTGCTGGGCGAGCTGACCCAGCAGCTGGCCAAGGCCACCGGCAAGCCCGCGCAGTACATAGCCGTGCACATCGTACCTGATCAGATGATGTCCTTGGGCTCCACGGATCCTTGCGCTCTCTGCAGCCTCTACAGCATTGGCAAAATTGGAGGGCAGCAGAACAAGACCTACACCAAGCTCCTGTGCGATATGATTGCGAAGCACTTGCACGTGTCTGCAGACAGGGTATACATCAACTACTTCGACATAAACGCTGCCAACGTG__________________________________________________________________________
Protein sequence:
Microsequence for 5 tryptic peptides of chick lens MIF and an N-terminal sequence were obtained and are shown in Table 1.
The four sequences compared are:
__________________________________________________________________________Human T-cell MIF (SEQ. ID. NO. 7)MPMFIVNTNVPRASVPDGFLSELTQQLAQATGKPPQYIAVHVVPDQLMAFGGSSEPCALCSLHSIGKIGGAQNRSYSKLLCGLLAERLRISPDRVYINYYDMNAASVGWNNSTFAMouse lens MIF (SEQ. ID. NO. 8)VNTNVPRASVPEGFLSELTQQLAQATGKPAQYIAVHVVPDQLMTFSGTNDPCALCSLHSIGKIGGAQNRNYSKLLCGLLSDRLHISPDRVYINYYDMNAANVGWNGSTFAChick lens MIF (SEQ. ID. NO. 9)PMFIIHTNVCKDAVPDSLLGELTQQLAKATGKPAQYIAVHIVPDQMMSLGGSTDPCALCSLYSIGKIGGQQNKTYTKLLCDMIAKHLHVSADRVYINYFDINAANVGWNNSTFAHuman lens MIF (SEQ. ID. NO. 10)VPRASVPDGFLSELTQQLAQATGKPPQYIAVHVVPDQIMAFGGSSEPCALCSLHSIGKIGGAQNRSYSKLLCGLLAERLRISPDRVYINYYDMNAANV__________________________________________________________________________ ##STR2## Deduced sequences of 10K/MIF proteins shown in Table 1.
Human T-cell MIF is from Weiser et al, Proc. Natl. Acad. Sci. U.S.A., 86, 7522-7526 (1989). Lens sequences are from cDNA library and PCR derived clones. Parts of the human lens 10K sequence were derived from the PCR oligos and are not shown. Peptides of chicken 10K/MIF are indicated by underline. The asterisk (*) shows the only difference between human lens and T-cell sequences.
The N-terminus of the lens 10K protein is at least partly unblocked. All sequences gave a partial match with the sequence of human MIF cloned from activated T-cells, Weiser et al, Proc. Natl. Acad. Sci. U.S.A., 86, 7522-7526 (1989). Sequences deduced from PCR and cDNA library clones confirmed this relationship. PCR clones for the coding region of human lens 10K protein were identical in sequence to the published sequence of human T-cell MIF except for one base identical in different PCR clones. Different PCR clones confirmed the difference. This single base change alters a predicted Serine residue to Asparagine, the identical amino acid found at the same position in mouse and chick cDNA clones and in chick protein sequence. It is possible that this conservative difference with the T-cell sequence results from conservative polymorphism or cloning or sequencing artifact. Such a change may or may not significantly change the properties of the protein.
Distribution of 10K/MIF:
PCR of RNA from dissected central epithelium, equatorial epithelium and fiber cells from 6, 12 and 14-day chick embryos showed that RNA for 10K/MIF is present in eqatorial and fiber cells at all stages but is absent from the central epithelium. Protein gels also confirm that 10K protein is detectable from 6 days and throughout chick lens development. A similar band is seen in all species examined, including bovine lenses. Northern blot analysis of mouse tissues using a mouse cDNA probe, show that 10K/MIF RNA is present in several tissues in addition to lens, particularly in brain and kidney.
EXAMPLE 2
The mouse cDNA is subcloned into a eukaryotic expression vector, pMAMNeo. PCR with added linker sequences is utilized to accomplish this so that a complete mouse MIF will be produced from its own initiator ATG in mammalian cells such as COS or NIH 3T3 cells.
EXAMPLE 3
The same clone of Example 2 is inserted into prokaryotic expression vector pKK233-2 to produce mouse MIF in E. coli.
__________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 10(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 295 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(ix) FEATURE:(A) NAME/KEY: CDS(B) LOCATION: 2..295(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:CGTGCCCCGCGCCTCCGTGCCGGACGGGTTCCTCTCCGAGCTCACC46ValProArgAlaSerValProAspGlyPheLeuSerGluLeuThr151015CAGCAGCTGGCGCAGGCCACCGGCAAGCCCCCCCAGTACATCGCGGTG94GlnGlnLeuAlaGlnAlaThrGlyLysProProGlnTyrIleAlaVal202530CACGTGGTCCCGGACCAGCTCATGGCCTTCGGCGGCTCCAGCGAGCCG142HisValValProAspGlnLeuMetAlaPheGlyGlySerSerGluPro354045TGCGCGCTCTGCAGCCTGCACAGCATCGGCAAGATCGGCGGCGCGCAG190CysAlaLeuCysSerLeuHisSerIleGlyLysIleGlyGlyAlaGln505560AACCGCTCCTACAGCAAGCTGCTGTGCGGCCTGCTGGCCGAGCGCCTG238AsnArgSerTyrSerLysLeuLeuCysGlyLeuLeuAlaGluArgLeu657075CGCATCAGCCCGGACAGGGTCTACATCAACTATTACGACATGAACGCG286ArgIleSerProAspArgValTyrIleAsnTyrTyrAspMetAsnAla80859095GCCAATGTG295AlaAsnVal(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 98 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:ValProArgAlaSerValProAspGlyPheLeuSerGluLeuThrGln151015GlnLeuAlaGlnAlaThrGlyLysProProGlnTyrIleAlaValHis202530ValValProAspGlnLeuMetAlaPheGlyGlySerSerGluProCys354045AlaLeuCysSerLeuHisSerIleGlyLysIleGlyGlyAlaGlnAsn505560ArgSerTyrSerLysLeuLeuCysGlyLeuLeuAlaGluArgLeuArg65707580IleSerProAspArgValTyrIleAsnTyrTyrAspMetAsnAlaAla859095AsnVal(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 459 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(ix) FEATURE:(A) NAME/KEY: CDS(B) LOCATION: 1..330(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:GTGAACACCAATGTTCCCCGCGCCTCCGTGCCAGAGGGGTTTCTGTCG48ValAsnThrAsnValProArgAlaSerValProGluGlyPheLeuSer151015GAGCTCACCCAGCAGCTGGCGCAGGCCACCGGCAAGCCCGCACAGTAC96GluLeuThrGlnGlnLeuAlaGlnAlaThrGlyLysProAlaGlnTyr202530ATCGCAGTGCACGTGGTCCCGGACCAGCTCATGACTTTTAGCGGCACG144IleAlaValHisValValProAspGlnLeuMetThrPheSerGlyThr354045AACGATCCCTGCGCCCTCTGCAGCCTGCACAGCATCGGCAAGATCGGT192AsnAspProCysAlaLeuCysSerLeuHisSerIleGlyLysIleGly505560GGTGCCCAGAACCGCAACTACAGTAAGCTGCTGTGTGGCCTGCTGTCC240GlyAlaGlnAsnArgAsnTyrSerLysLeuLeuCysGlyLeuLeuSer65707580GATCGCCTGCACATCAGCCCGGACCGGGTCTACATCAACTATTACGAC288AspArgLeuHisIleSerProAspArgValTyrIleAsnTyrTyrAsp859095ATGAACGCTGCCAACGTGGGCTGGAACGGTTCCACCTTCGCT330MetAsnAlaAlaAsnValGlyTrpAsnGlySerThrPheAla100105110TGAGTCCTGGCCCCACTTACCTGCACCGCTGTTCTTTGAGCCTCGCTCCACGTAGTGTTC390TGTGTTTATCCACCGGTAGCGATGCCCACCTTCCAGCCGGGAGAAATAAATGGTTTATAA450GAGAAAAAA459(2) INFORMATION FOR SEQ ID NO:4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 110 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:ValAsnThrAsnValProArgAlaSerValProGluGlyPheLeuSer151015GluLeuThrGlnGlnLeuAlaGlnAlaThrGlyLysProAlaGlnTyr202530IleAlaValHisValValProAspGlnLeuMetThrPheSerGlyThr354045AsnAspProCysAlaLeuCysSerLeuHisSerIleGlyLysIleGly505560GlyAlaGlnAsnArgAsnTyrSerLysLeuLeuCysGlyLeuLeuSer65707580AspArgLeuHisIleSerProAspArgValTyrIleAsnTyrTyrAsp859095MetAsnAlaAlaAsnValGlyTrpAsnGlySerThrPheAla100105110(2) INFORMATION FOR SEQ ID NO:5:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 292 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(ix) FEATURE:(A) NAME/KEY: CDS(B) LOCATION: 2..292(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:CGTCTGCAAGGACGCCGTGCCCGACAGCCTGCTGGGCGAGCTGACC46ValCysLysAspAlaValProAspSerLeuLeuGlyGluLeuThr151015CAGCAGCTGGCCAAGGCCACCGGCAAGCCCGCGCAGTACATAGCCGTG94GlnGlnLeuAlaLysAlaThrGlyLysProAlaGlnTyrIleAlaVal202530CACATCGTACCTGATCAGATGATGTCCTTGGGCTCCACGGATCCTTGC142HisIleValProAspGlnMetMetSerLeuGlySerThrAspProCys354045GCTCTCTGCAGCCTCTACAGCATTGGCAAAATTGGAGGGCAGCAGAAC190AlaLeuCysSerLeuTyrSerIleGlyLysIleGlyGlyGlnGlnAsn505560AAGACCTACACCAAGCTCCTGTGCGATATGATTGCGAAGCACTTGCAC238LysThrTyrThrLysLeuLeuCysAspMetIleAlaLysHisLeuHis657075GTGTCTGCAGACAGGGTATACATCAACTACTTCGACATAAACGCTGCC286ValSerAlaAspArgValTyrIleAsnTyrPheAspIleAsnAlaAla80859095AACGTG292AsnVal(2) INFORMATION FOR SEQ ID NO:6:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 97 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:ValCysLysAspAlaValProAspSerLeuLeuGlyGluLeuThrGln151015GlnLeuAlaLysAlaThrGlyLysProAlaGlnTyrIleAlaValHis202530IleValProAspGlnMetMetSerLeuGlySerThrAspProCysAla354045LeuCysSerLeuTyrSerIleGlyLysIleGlyGlyGlnGlnAsnLys505560ThrTyrThrLysLeuLeuCysAspMetIleAlaLysHisLeuHisVal65707580SerAlaAspArgValTyrIleAsnTyrPheAspIleAsnAlaAlaAsn859095Val(2) INFORMATION FOR SEQ ID NO:7:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 115 amino acids(B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:MetProMetPheIleValAsnThrAsnValProArgAlaSerValPro151015AspGlyPheLeuSerGluLeuThrGlnGlnLeuAlaGlnAlaThrGly202530LysProProGlnTyrIleAlaValHisValValProAspGlnLeuMet354045AlaPheGlyGlySerSerGluProCysAlaLeuCysSerLeuHisSer505560IleGlyLysIleGlyGlyAlaGlnAsnArgSerTyrSerLysLeuLeu65707580CysGlyLeuLeuAlaGluArgLeuArgIleSerProAspArgValTyr859095IleAsnTyrTyrAspMetAsnAlaAlaSerValGlyTrpAsnAsnSer100105110ThrPheAla115(2) INFORMATION FOR SEQ ID NO:8:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 110 amino acids(B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:ValAsnThrAsnValProArgAlaSerValProGluGlyPheLeuSer151015GluLeuThrGlnGlnLeuAlaGlnAlaThrGlyLysProAlaGlnTyr202530IleAlaValHisValValProAspGlnLeuMetThrPheSerGlyThr354045AsnAspProCysAlaLeuCysSerLeuHisSerIleGlyLysIleGly505560GlyAlaGlnAsnArgAsnTyrSerLysLeuLeuCysGlyLeuLeuSer65707580AspArgLeuHisIleSerProAspArgValTyrIleAsnTyrTyrAsp859095MetAsnAlaAlaAsnValGlyTrpAsnGlySerThrPheAla100105110(2) INFORMATION FOR SEQ ID NO:9:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 114 amino acids(B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:ProMetPheIleIleHisThrAsnValCysLysAspAlaValProAsp151015SerLeuLeuGlyGluLeuThrGlnGlnLeuAlaLysAlaThrGlyLys202530ProAlaGlnTyrIleAlaValHisIleValProAspGlnMetMetSer354045LeuGlyGlySerThrAspProCysAlaLeuCysSerLeuTyrSerIle505560GlyLysIleGlyGlyGlnGlnAsnLysThrTyrThrLysLeuLeuCys65707580AspMetIleAlaLysHisLeuHisValSerAlaAspArgValTyrIle859095AsnTyrPheAspIleAsnAlaAlaAsnValGlyTrpAsnAsnSerThr100105110PheAla(2) INFORMATION FOR SEQ ID NO:10:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 98 amino acids(B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:ValProArgAlaSerValProAspGlyPheLeuSerGluLeuThrGln151015GlnLeuAlaGlnAlaThrGlyLysProProGlnTyrIleAlaValHis202530ValValProAspGlnLeuMetAlaPheGlyGlySerSerGluProCys354045AlaLeuCysSerLeuHisSerIleGlyLysIleGlyGlyAlaGlnAsn505560ArgSerTyrSerLysLeuLeuCysGlyLeuLeuAlaGluArgLeuArg65707580IleSerProAspArgValTyrIleAsnTyrTyrAspMetAsnAlaAla859095AsnVal__________________________________________________________________________ | Macrophage Migration Inhibition Factor (MIF) can be obtained from ocular lens of various birds and mammals. The amino acid sequences of lens MIF from mice, chickens and humans has been determined and the corresponding cDNA has been cloned. |
This is a division of application Ser. No. 08/012,379, filed Feb. 2, 1993 pending, and U.S. application Ser. No. 08/236,190 filed May 2, 1994 pending.
FIELD OF THE INVENTION
The invention relates to the therapeutic methods and articles of manufacture to alleviate the tobacco withdrawal syndrome or manage human body weight with the use of nicotine metabolites or pharmaceutically acceptable salts thereof. The invention includes methods and articles of manufacture using nicotine metabolites or pharmaceutically acceptable salts thereof to alleviate symptoms of nicotine withdrawal and craving associated with cessation of tobacco or nicotine use, as well as the management of human body weight in nicotine-experienced or nicotine-naive humans.
BACKGROUND OF THE INVENTION
Cigarette smoking continues to be the major preventable cause of death in the United States resulting in nearly 400,000 deaths per year due to cancer and cardiovascular disease. Despite the potential adverse health effects, the vast majority of cigarette smokers are unable to cease smoking. The lack of smoking cessation success is thought to be related to the tobacco withdrawal syndrome or tobacco abstinence syndrome that most smokers experience during their attempts to quit. See, Office of Smoking and Health, The Health Consequences of Smoking: Nicotine Addiction. A Report to the Surgeon General, U.S. Govt. Print. Off., Washington D.C., DHHS Pub. No. (CDC) 88-8406 (1988). The most common effects are similar to those in almost all abstinence syndromes, and include decreased heart rate, anxiety, tension, difficulty concentrating, impatience, depression, increased appetite with accompanied weight gain, irritability and restlessness. See, American Psychiatric Assoc., Diagnostic and Statistical Manual, Washington D.C. (3rd ed. 1980) at pages 159-160, 176-178. Most withdrawal effects occur within 24 hours, peak in the first 1-2 weeks and significantly decrease at one month. It is widely believed that the effects of abstinence from tobacco are due to nicotine deprivation, and that abstinence effects from smoking prevent smokers from stopping. See, J. R. Hughes et al., in Research and Advances in Alcohol and Drug Problems, Vol. 10, L. T. Kozlowski et al., eds., Plenum Pub. Corp. (1990) at pages 317-398.
The relationship between tobacco use and decreased body weight has been known for more than 100 years. It has been well established that smokers weigh less than non-smokers. Recent research has shown that nicotine is the substance responsible for the decreased body weight of tobacco users (See, Chapter on Nicotine Dependence, The National Institute On Drug Abuse's Fourth Triennial Report to Congress, In Press). Two major factors related to nicotine use cessation are responsible for weight gain in the post-tobacco cessation period including 1) decreased metabolism and/or 2) increased dietary intake. Conversely, it must be the case that nicotine use results in increased metabolism and/or decreased dietary intake.
In an attempt to reduce post-cessation weight gain and achieve long-term tobacco cessation success, the effects of nicotine replacement (nicotine gum) on post-cessation weight gain were examined over a ten week post-cessation period. Nicotine gum when compared to placebo was shown to reduce the weight gained in the post-cessation period by approximately 50 percent (3.8 versus 7.8 pounds, respectively), and the magnitude of this beneficial effect was related to the amount of nicotine gum used. Similarly, it was found that nicotine gum use by abstinent cigarette smokers reduced the frequency and severity of self-reported "Hunger" scores and self-reported eating over the first month of nicotine abstinence. Increases in self-reported measures of hunger are likely related to increased weight gain in the post-cessation period (See, chapter on Nicotine Dependence, The National Institute On Drug Abuse's Fourth Triennial Report to Congress, In Press). As a result of the above findings, the use of an appetite suppressant, therefore, should prevent post-cessation weight gain in nicotine-experienced individuals.
Of the pharmacological approaches to aiding tobacco use cessation, nicotine replacement, e.g., via transdermal nicotine patches or nicotine gum, is the most widely used. Nicotine gum decreases abstinence discomfort, especially anxiety, decreased memory and irritability. On the other hand, nicotine gum does not reliably decrease weight gain or craving. Also, discontinuing use of nicotine gum leads to some of the same symptoms as the cigarette withdrawal syndrome. Furthermore, nicotine is toxic, and the availability of nicotine gum or patches poses a risk of poisoning to children and pets.
Other studies have demonstrated that alpha-2 agonists, such as clonidine, decrease postcessation anxiety, irritability and difficulty concentrating. Decreased sympathetic activity has been postulated to be the mechanism by which these drugs decrease abstinence effects. Although tobacco abstinence has some effects that could be attributed to sympathetic activity, it lacks the typical signs and symptoms of sympathetic overactivity, such as tachycardia, diaphoresis and hypertension. Thus, the mechanism by which alpha-2 agonists exert their effects is unclear. While a number of other pharmacological treatments, such as use of doxepin, ACTH, and corticotrophins, for abstinence symptoms have been tested, none of the studies reported baseline and postcessation values for abstinence symptoms. See, for example, S. J. Bourne (U.S. Pat. No. 4,621,074).
Therefore, a continuing need exists for pharmacological treatments that will facilitate smoking cessation, e.g., by blocking or relieving tobacco withdrawal syndrome, or reducing the symptoms of nicotine withdrawal. Also, a weight management agent should prove useful as a tool to assist the tobacco user in their cessation attempt.
SUMMARY OF THE INVENTION
The present invention provides a therapeutic method of treatment to (a) alleviate tobacco withdrawal syndrome (TWS), (b) alleviate the similar abstinence effects due to cessation of nicotine alone, or (c) manage body weight in nicotine-experienced or nicotine-naive individuals comprising of administering to a human in need of such treatment, i.e., a nicotine user, abstinent nicotine user or nicotine-naive, an amount of a nicotine metabolite or a combination of nicotine metabolites (e.g., cotinine, nornicotine, norcotinine, nicotine N-oxide, cotinine N-oxide, 3-hydroxycotinine, 5-hydroxycotinine) or their pharmaceutically acceptable salts thereof, in an amount effective to significantly reduce or eliminate at least one of the symptoms of TWS or nicotine withdrawal. As discussed above, the symptoms of both tobacco and nicotine withdrawal are similar and are art recognized to include craving for tobacco, anxiety, irritability, insomnia, impatience, tension, depression, increased appetite with accompanying weight gain, restlessness, difficulty concentrating, drowsiness and decreased heart rate. The present method is effective both to alleviate TWC acutely and to permit patients to maintain abstinence from tobacco use for extended periods of time.
In a preferred embodiment, the present invention also provides a therapeutic method to alleviate the craving for cigarettes, tobacco and/or nicotine that is associated with cessation of nicotine use, e.g., by chewing or smoking, by the administration of an effective amount of a nicotine metabolite or a combination of nicotine metabolites or their pharmaceutically acceptable salts thereof, to a human in need of such treatment. However, the present invention is also useful to treat the symptoms of nicotine withdrawal which are due, for example, to cessation of use of nicotine gum or a nicotine transdermal patch. In addition, this invention should be useful in the management of human body weight in nicotine-experienced or nicotine-naive individuals.
The present invention is exemplified by a study in which a nicotine metabolite, (-)-cotinine base, was intravenously administered to abstinent cigarette smokers. The administration of the nicotine metabolite, cotinine, caused many subjective changes without affecting cardiovascular activity. While cotinine administration appeared to mildly exacerbate some of the symptoms of the tobacco withdrawal syndrome such as anxiety, tension, restlessness and insomnia, it simultaneously decreased ratings of sedation and hunger. Also, cotinine administration reduced peak craving scores for cigarettes, tobacco and/or nicotine experienced during the session.
Nicotine metabolites may have many qualities which can enhance their value as aids to smoking cessation. In particular, cotinine has a long in vivo half-life, no cardiovascular activity, complete oral bioavailability, potentially low abuse liability and has not been reported to be harmful even at very high doses in many species including man. Also, because cotinine has no significant cardiovascular effect, a combined pharmacologic replacement treatment approach using cotinine in combination with nicotine or other metabolites of nicotine may be possible. The other nicotine metabolites should have many of these same qualities, and therefore should provide relief from the aforementioned problems in a similar manner.
The present invention also provides an article of manufacture comprising packaging material, such as a box, bottle, tube, sprayer, insufflator, intravenous (i.v.) bag, envelope and the like; and at least one unit dosage form of a pharmaceutical agent contained within said packaging material, wherein said pharmaceutical agent comprises a nicotine metabolite or combination of nicotine metabolites or their pharmaceutically acceptable salts thereof in an amount effective to alleviate tobacco withdrawal syndrome, the symptoms of nicotine withdrawal or the craving associated with cessation of tobacco smoking or manage human body weight, and wherein said packaging material includes instruction means which indicate that said nicotine metabolite or combination of nicotine metabolites or said pharmaceutically acceptable salts thereof can be used for alleviating tobacco withdrawal syndrome, the symptoms of nicotine withdrawal, the craving associated with the cessation of tobacco smoking or manage human body weight. Suitable instruction means include printed labels, printed package inserts, tags, cassette tapes, and the like.
DETAILED DESCRIPTION OF THE INVENTION
Cotinine ##STR1## Cotinine has the molecular structure shown above;
The physiologically active form is the (-)-isomer, so as used herein, the term "cotinine" includes (-)-cotinine, or the racemic form, (+/-)-cotinine. The free base, depicted above, can be employed in the practice of the invention, as can the pharmaceutically acceptable salts. These include the amine-acid addition salts of nontoxic organic acids or inorganic acids, such as the tartarate, fumarate ("scotine"), citrate, maleate, malate, hydrobromide, hydrochloride, sulfate, phosphate and the like. For example, see F. Vaitekunas, J. Amer. Chem. Soc., 79, 149 (1957). E. R. Bowman et al., in J. Pharmacol. Exp. Ther., 135, 306 (1962) report the preparation of (-)-cotinine free base from (-)-nicotine. The preparation and purification of (-)-cotinine fumarate is described by N. L. Benowitz et al., Clin. Pharmacol. Ther., 34, 604 (1983). Also, see P. Jacob III, et al., in Pharmacol. Biochem. Behav., 30, 249 (1988) for an explanation of the metabolic pathways of nicotine and the formation of this metabolic product are discussed.
Nornicotine ##STR2## Nornicotine has the molecular structure shown above;
The physiologically active form is the (-)-isomer, so as used herein, the term "nornicotine" includes (-)-nornicotine, or the racemic form, (+/-)-nornicotine. The free base, depicted above, can be employed in the practice of the invention, as can the pharmaceutically acceptable salts. These include the amine-acid addition salts of nontoxic organic acids or inorganic acids, such as the tartarate, fumarate, citrate, maleate, malate, hydrobromide, hydrochloride, sulfate, phosphate and the like. For example, see P. Jacob III, et al., in Pharmacol. Biochem. Behav., 30, 249 (1988) for an explanation of the metabolic pathways of nicotine and the formation of this metabolic product are discussed.
Norcotinine ##STR3## Norcotinine has the molecular structure shown above;
The physiologically active form is the (-)-isomer, so as used herein, the term "norcotinine" includes (-)-norcotinine, or the racemic form, (+/-)-norcotinine. The free base, depicted above, can be employed in the practice of the invention, as can the pharmaceutically acceptable salts. These include the amine-acid addition salts of nontoxic organic acids or inorganic acids, such as the tartarate, fumarate, citrate, maleate, malate, hydrobromide, hydrochloride, sulfate, phosphate and the like. For example, see P. Jacob III, et al., in Pharmacol. Biochem. Behav., 30, 249 (1988) for an explanation of the metabolic pathways of nicotine and the formation of this metabolic product are discussed.
Nicotine N-Oxide ##STR4## Nicotine N-oxide has the molecular structure shown above;
The physiologically active form is the (-)-isomer, so as used herein, the term "nicotine N-oxide" includes (-)-nicotine N-oxide, or the racemic form, (+/-)-nicotine N-oxide. The free base, depicted above, can be employed in the practice of the invention, as can the pharmaceutically acceptable salts. These include the amine-acid addition salts of nontoxic organic acids or inorganic acids, such as the tartarate, fumarate, citrate, maleate, malate, hydrobromide, hydrochloride, sulfate, phosphate and the like. For example, see P. Jacob III, et al., in Pharmacol. Biochem. Behav., 30, 249 (1988) for an explanation of the metabolic pathways of nicotine and the formation of this metabolic product are discussed.
Cotinine N-Oxide ##STR5## Cotinine N-oxide has the molecular structure shown above;
The physiologically active form is the (-)-isomer, so as used herein, the term "cotinine N-oxide" includes (-)-cotinine N-oxide, or the racemic form, (+/-)-cotinine N-oxide. The free base, depicted above, can be employed in the practice of the invention, as can the pharmaceutically acceptable salts. These include the amine-acid addition salts of nontoxic organic acids or inorganic acids, such as the tartarate, fumarate, citrate, maleate, malate, hydrobromide, hydrochloride, sulfate, phosphate and the like. For example, see P. Jacob III, et al., in Pharmacol. Biochem. Behav., 30, 249 (1988) for an explanation of the metabolic pathways of nicotine and the formation of this metabolic product are discussed.
3-Hydroxycotinine ##STR6## 3-Hydroxycotinine has the molecular structure shown above;
The physiologically active form is the (-)-isomer, so as used herein, the term "3-hydroxycotinine" includes (-)-3-hydroxycotinine, or the racemic form, (+/-)-3-hydroxycotinine. The free base, depicted above, can be employed in the practice of the invention, as can the pharmaceutically acceptable salts. These include the amine-acid addition salts of nontoxic organic acids or inorganic acids, such as the tartarate, fumarate, citrate, maleate, malate, hydrobromide, hydrochloride, sulfate, phosphate and the like. For example, see P. Jacob III, et al., in Pharmacol. Biochem. Behav., 30, 249 (1988) for an explanation of the metabolic pathways of nicotine and the formation of this metabolic product are discussed.
5-Hydroxycotinine ##STR7## 5-Hydroxycotinine has the molecular structure shown above;
The physiologically active form is the (-)-isomer, so as used herein, the term "5-hydroxycotinine" includes (-)-5-hydroxycotinine, or the racemic form, (+/-)-5-hydroxycotinine. The free base, depicted above, can be employed in the practice of the invention, as can the pharmaceutically acceptable salts. These include the amine-acid addition salts of nontoxic organic acids or inorganic acids, such as the tartarate, fumarate, citrate, maleate, malate, hydrobromide, hydrochloride, sulfate, phosphate and the like. Also, see P. Jacob III, et al., in Pharmacol. Biochem. Behav., 30, 249 (1988) for an explanation of the metabolic pathways of nicotine and the formation of this metabolic product are discussed.
Cotinine is the major metabolite of nicotine which accumulates in the body as a result of nicotine exposure and has previously been believed to be pharmacologically inactive. For example, see N. L. Benowitz, "The use of biologic fluid samples in assessing tobacco smoke consumption", in Measurement in the Analysis and Treatment of Smoking Behavior, J. Grabowski et al., eds., NIDA Research Monograph No. 48, UPHS, ADAMHA (1983). In contrast to nicotine, cotinine has a relatively long terminal elimination half-life (two versus sixteen hours, respectively). Due to this pharmacological characteristic, cotinine has become the principally used objective biochemical marker of nicotine exposure in cigarette smoking and/or cessation-related research paradigms.
While cotinine is a well-known metabolite of nicotine and is routinely measured in many laboratories, no systematic investigation of the physiological and subjective effects produced by intravenous cotinine administration has been performed in humans. K. I. Yamamoto et al., International J. Neuropharmacol., 4, 359 (1965), reported that intravenous cotinine produced increases in EEG activity and behavioral arousal in cats with only a slight decrease in blood pressure. In squirrel monkeys, intramuscular cotinine injections increased rates of responding on fixed interval schedules of reinforcement over a wide range of doses (M. E. Risner et al., J. Pharmacol. Exp. Ther., 234, 113 (1985); S. R. Goldberg et al., Psychopharmacology, 97, 295 (1989)). These findings, taken together, suggest that cotinine acts as a psychomotor stimulant. However, the pharmacologic mechanism of action has yet to be determined.
In two recent human studies, the pharmacokinetic profiles of intravenous and orally administered cotinine were examined without emphasis on measuring the subjective and/or physiological changes induced by this compound (N. L. Benowitz et al., Clin. Pharmacol. Ther., 34, 604 (1983); P. J. DeSchepper et al., Eur. J. Pharmacol., 31, 583 (1987)). Moreover, using an uncontrolled experimental design, Benowitz et al., Clin. Pharmacol. Ther., 34, 604 (1988), found that intravenous cotinine produced no cardiovascular changes and only slight differences in various subjective ratings which were comparable to placebo-induced changes found in other experiments with nicotine. Consequently, Benowitz and his colleagues concluded that cotinine lacked significant pharmacologic activity in humans.
While the most extensively studied metabolite of nicotine is cotinine, other work has examined the behavioral effects of other nicotine metabolites. In squirrel monkeys and beagle dogs, intramuscular nornicotine injections increased rates of responding on fixed interval schedules of reinforcement and was discriminated as nicotine using a discrimination procedure (M. E. Risner et al., J. Pharmacol, Exp. Ther., 224, 113 (1985); S. R. Goldberg et al., Psychopharmacology, 97, 295 (1989)). These findings suggest that nornicotine is psychoactive. In another studying pharmacokinetics, G. Scherer et al., Klin Wochenschr, 66, 5 (1988), intravenously administered (-)-3-hydroxycotinine to male cigarette smokers and determined its half-life to be approximately six hours. No mention was made of toxic side effects or specific activity from the drug.
Administration and Dosages
While it is possible that, for use in therapy, nicotine metabolites and/or their salts thereof may be administered as the pure chemicals, as by inhalation of a fine powder via an insufflator, it is preferable to present the active ingredient as a pharmaceutical formulation. The invention thus further provides a pharmaceutical formulation comprising of a nicotine metabolite or combination of nicotine metabolites or their pharmaceutically acceptable salts thereof, together with one or more pharmaceutically acceptable carriers therefor and, optionally, other therapeutic and/or prophylactic ingredients. The carrier(s) must be acceptable, in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.
Pharmaceutical formulations include those suitable for oral or parenteral (including intramuscular, subcutaneous and intravenous) administration. Forms suitable for parenteral administration also include forms suitable for administration by inhalation or insufflation or for nasal, or topical (including buccal, rectal, vaginal and sublingual) administration. The formulations may, where appropriate, be conveniently presented in discrete unit dosage forms and may be prepared by any of the methods well known in the art of pharmacy. Such methods include the step of bringing into association the active compound with liquid carriers, solid matrices, semi-solid carriers, finely divided solid carriers or combinations thereof, and then, if necessary, shaping the product into the desired delivery system.
Pharmaceutical formulations suitable for oral administration may be presented as discrete unit dosage forms such as hard or soft gelatin capsules, cachets or tablets each containing a predetermined amount of the active ingredient; as a powder or as granules; as a solution, a suspension or as an emulsion; or in a chewable base such as a synthetic resin or chicle for ingestion of the cotinine from a chewing gum. The active ingredient may also be presented as a bolus, electuary or paste. Tablets and capsules for oral administration may contain conventional excipients such as binding agents, fillers, lubricants, disintegrants, or wetting agents. The tablets may be coated according to methods well known in the art, i.e., with enteric coatings.
Oral liquid preparations may be in the form of, for example, aqueous or oily suspensions, solutions, emulsions, syrups or elixirs, or may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, emulsifying agents, non-aqueous vehicles (which may include edible oils), or preservatives.
The compounds according to the invention may also be formulated for parenteral administration (e.g., by injection, for example, bolus injection or continuous infusion) and may be presented in unit dose form in ampules, prefilled syringes, small volume infusion containers or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilization from solution, for constitution with a suitable vehicle, e.g., sterile, pyrogen-free water, before use.
For topical administration to the epidermis, a nicotine metabolite or combination of nicotine metabolites may be formulated as ointments, creams or lotions, or as the active ingredient of a transdermal patch. Suitable transdermal delivery systems are disclosed, for example, in A. Fisher et al. (U.S. Pat. No. 4,788,063), or R. Bawa et al. (U.S. Pat. Nos. 4,931,279, 4,668,506 and 4,713,244). Ointments and creams may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening and/or gelling agents. Lotions may be formulated with an aqueous or oily base and will in general also contain one or more emulsifying agents, stabilizing agents, dispersing agents, suspending agents, thickening agents, or coloring agents. The active ingredient can also be delivered via iontophoresis, e.g., as disclosed in U.S. Pat. Nos. 4,140,122, 4,383,529, or 4,051,842.
Formulations suitable for topical administration in the mouth include unit dosage forms such as lozenges comprising active ingredient in a flavored base, usually sucrose and acadia or tragacanth; pastilles comprising the active ingredient in an inert base such as gelatin and glycerin or sucrose and acacia; mucoadherent gels, and mouthwashes comprising the active ingredient in a suitable liquid carrier. When desired, the above-described formulations can be adapted to give sustained release of the active ingredient employed, e.g., by combination with certain hydrophilic polymer matrices, e.g., comprising natural gels, synthetic polymer gels or mixtures thereof.
Pharmaceutical formulations suitable for rectal preferably presented as unit dose suppositories. Suitable carriers include cocoa butter and other materials commonly used in the art, and the suppositories may be conveniently formed by admixture of the active compound with the softened or melted carrier(s) followed by chilling and shaping in molds.
Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or sprays containing, in addition to the active ingredient, such carriers as are known in the art to be appropriate.
For administration by inhalation, the compounds according to the invention are conveniently delivered from an insufflator, nebulizer or a pressurized pack or other convenient means of delivering an aerosol spray.
Pressurized packs may comprise a suitable propellant such as dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol, the dosage unit may be determined by providing a valve to deliver a metered amount.
Alternatively, for administration by inhalation or insufflation, the compounds according to the invention may take the form of a dry powder composition, for example, a powder mix of the compound and a suitable powder base such as lactose or starch. The powder composition may be presented in unit dosage form in, for example, capsules or cartridges or, e.g., gelatin or blister packs from which the powder may be administered with the aid of an inhalator or insufflator.
For intranasal administration, the compounds of the invention may be administered via a liquid spray, such as via a plastic bottle atomizer. Typical of these are the Mistometer a (Wintrop) and Medihaler (Riker).
For topical administration to the eye, the nicotine metabolite or combination of nicotine metabolites can be administered as drops, gels (see, S. Chrai et al., U.S. Pat. No. 4,255,415), gums (see S. L. Lin et al., U.S. Pat. No. 4,136,177) or via a prolonged-release ocular insert (see A. S. Michaels, U.S. Pat. No. 3,867,519 and H. M. Haddad et al., U.S. Pat. No. 3,870,791).
The pharmaceutical compositions according to the invention may also contain other adjuvants such as flavorings, colorings, antimicrobial agents, or preservatives.
It will be further appreciated that the amount of a nicotine metabolite or combinartion of nicotine metabolites, or their active salts or derivative thereof, required for use in treatment will vary not only with the particular salt selected but also with the route of administration, the nature of the condition being treated and the age and condition of the patient and will be ultimately at the discretion of the attending physician or clinician.
In general, however, a suitable dose will be in the range of from about 1 to about 100 mg/kg, e.g., from about 10 to about 75 mg/kg of body weight per day, such as 3 to about 50 mg per kilogram body weight of the recipient per day, preferably in the range of 6 to 90 mg/kg/day, most preferably in the range of 15 to 60 mg/kg/day, calculated as the nicotine metabolite in the free base form.
The compound is conveniently administered in unit dosage form; for example, containing 5 to 1000 mg, conveniently 10 to 750 mg, most conveniently, 50 to 500 mg of active ingredient per unit dosage form.
Ideally, the active ingredient should be administered to achieve peak plasma concentrations of the active compound of from about 0.5 to about 75 PM, preferably, about 1 to 50 pM, most preferably, about 2 to about 30 pM. This may be achieved, for example, by the intravenous injection of a 0.05 to 5% solution of the active ingredient, optionally in saline, or orally administered as a bolus containing about 1-100 mg of the active ingredient.
Desirable blood levels may be maintained by continuous infusion to provide about 0.01-5.0 mg/kg/hr or by intermittent infusions containing about 0.4-15 mg/kg of the active ingredient(s).
The desired dose may conveniently be presented in a single dose or as divided doses administered at appropriate intervals, for example, as two, three, four or more sub-doses per day. The sub-dose itself may be further divided, e.g., into a number of discrete loosely spaced administrations; such as multiple inhalations from an insufflator or by application of a plurality of drops into the eye.
The invention will be further described by reference to the following detailed Example.
Example I: Intravenous Administration of (-)-Cotinine
A. Subjects
Participants included 18 healthy male volunteers between the ages of 18 and 40 years old who had 1) no history of psychiatric, alcohol and drug abuse disorders, 2) smoked at least one pack of cigarettes per day for one year prior to study admission, 3) an expired-air carbon monoxide concentration of greater than 20 ppm, 4) not currently on any medication, and 5) not donated blood in the past 90 days. Potential subjects were carefully screened for physical and mental health problems.
B. Drug Preparation and Administration Procedures
(-)-Cotinine base was synthesized from (-)-nicotine using the bromine-zinc oxidation method described by E. R. Bowman et al., Biochem. Preparations, 10, 36 (1963). Hereinafter, the term "cotinine" will be used to refer to (-)-cotinine. The cotinine base was analyzed for impurities using gas chromatography/mass spectrometry and thin layer chromatography and found to be pure. Using sterile techniques, cotinine solution was prepared for intravenous administration. Cotinine base was combined with sterile normal saline solution to achieve a concentration of three mg of cotinine base per one ml of solution. This solution was autoclaved and found to be non-pyrogenic using a standard pyrogenicity testing. The cotinine solution was again tested for molecular structure integrity and concentration accuracy. Next, 10 ml of cotinine solution (30 mg cotinine) were placed into 20 ml injection vials, sealed and stored in a refrigerator until used. The placebo was ten ml of sterile normal saline solution. Placebo and active drug vials were prepared and labeled in a double-blind manner by pharmacy personnel. In addition to pharmacy personnel, one study physician who had no contact with subjects during the experimental sessions had access to the drug code in the event of a medical emergency.
During sessions, subjects received 10 ml (30 mg) of cotinine base solution diluted to 15 ml with sterile normal saline solution or placebo (15 ml of sterile saline solution) infused intravenously through a 20 gauge indwelling intravenous catheter. This infusion rate was chosen so as not to exceed two mg per minute of cotinine delivered to the subject. Infusions were performed using a controlled-rate syringe infusion pump. All subjects received cotinine and placebo infusions using a randomly assigned double-blind counterbalanced-order design.
C. Dependent Measures
The physiological parameters monitored included heart rate, systolic, diastolic and mean arterial blood pressure, and a 12-lead electrocardiogram (ECG) with measurement of PR, QRS and QT intervals. The biochemical parameters included expired-air carbon monoxide level (CO), serum nicotine and cotinine concentrations. Carbon monoxide was measured using standard techniques. The serum nicotine and cotinine concentration assays were performed using gas chromatography and mass spectrometry at the Laboratory of Physiological Hygiene at the University of Minnesota Medical School.
Self-reported ratings of subjective state, mood and cigarette withdrawal symptoms were obtained from the subjects. These measures included the Profile of Mood States questionnaire (POMS), several 100 mm visual analog scales (VAS) and the cigarette withdrawal symptoms checklist (WSC) of symptoms related to the cigarette withdrawal syndrome (J. R. Hughes et al., Arch. Gen. Psychiatry, 43, 289, (1986)). The Record of Withdrawal Symptom is a O=(none) to 5=(severe) scale of 12 symptoms associated with TWS: craving for nicotine, irritable/angry, anxious/tense, difficulty concentrating, restless, impatient, excessive hunger, insomnia, increased eating, drowsiness, headaches and miscellaneous group including tremor, heart racing, sweating, dizzy or g.i. problems.
Two 100 mm VAS forms were used. One with 11 adjectives including "Pleasant", "Need for Cigarettes", "Energy", "Hungry", "Down", "Sedated", "Anxious", "Stimulated", "Fatigue", "Craving for Cigarettes" and a separate VAS for "Craving for Tobacco" rated form none to extremely. From the VAS forms, a measure of "Vigor" was created by subtracting the sedation score from the stimulation score. Also, an adverse effects questionnaire (AEQ) was used to assess possible problems associated with cotinine administration. These problems were restlessness, headaches, tachycardia/palpatations, tremor, excessive sweating, nausea/vomiting, upset stomach, lightheadedness/dizzy, drowsy, irritable, and excessive salivation. The symptoms assessed were those known to be experienced following nicotine administration.
D. Procedure
This study was performed on an outpatient basis over nine days. Subjects were required to attend five scheduled laboratory sessions. All sessions were held at the Tobacco Research Laboratory associated with the University of Minnesota Hospital Complex. The first session was used for obtaining informed consent, physical and psychological screening of the prospective participants, background and baseline data collection. Also, the subject habituated to the data collection procedures utilized during the sessions. If the participant met inclusion criteria, he was scheduled for his next visit. Prior to session 2, the subject was randomly-assigned to one of the two cotinine administration order conditions.
Sessions 2 and 4 were used to collect data for all dependent variables under conditions of ad libitum cigarette smoking and serving as a baseline from which to assess tobacco withdrawal induced changes measured at the beginning of sessions 3 and 5, respectively. All sessions were scheduled to begin between 5 and 7 pm. Sessions 2 and 4 were held seven days apart and lasted approximately 15 minutes. During these sessions, vital signs, CO, WSC, VAS, POMS and AEQ were completed. Blood was drawn for later measurement of serum nicotine and cotinine concentration. At the end of sessions 2 and 4 and after departing the laboratory, subjects were required to refrain from cigarette smoking and other forms of tobacco use over the next 48 hours. At the end of this 48 hour period following sessions 2 and 4, subjects reported to the laboratory for the two drug infusion sessions 3 and 5, respectively.
During sessions 3 and 5, subjects received cotinine and placebo infusions in a counterbalanced order during these sessions. Sessions 3 and 5 were held 48 hours after sessions 2 and 4 during which time the subject was to remain tobacco abstinent. Abstinence was determined by using biochemical markers of smoke exposure including CO and serum cotinine concentrations. After the subject reported to the laboratory, baseline measurements of CO, vital signs, WSC, VAS, POMS and AEQ were made. Next, the ECG electrodes were attached to the chest wall and limbs. A 20 gauge indwelling intravenous catheter was placed in a prominent vein in the non-dominant forearm in order to allow the subject to freely complete subjective effects questionnaires during the remainder of the session. The catheter was used for intravenous drug administration and access in the event of an adverse medical event. Heart rate and blood pressure were recorded. Using standard venipuncture techniques, five mls of blood was drawn from the antecubital area of the dominant arm for later serum nicotine and cotinine concentration analyses. At intervals of 5, 15, 30, 60 and 120 minutes after the drug infusion, heart rate, blood pressure, ECG, WSC, VAS, AEQ were completed, and blood was drawn for later serum nicotine and cotinine concentration analyses. Also, the POMS was completed at 30, 60 and 120 minutes after drug administration. The blood samples were allowed to stand for 30 minutes, centrifuged for 10 minutes and the serum was pipetted into plastic cryovials for storage in a -20 degree C. freezer until the nicotine/cotinine assays were performed.
E. Statistical Analyses
All questionnaires were scored and entered into a computer by a research assistant who was blind to the dosing conditions. At the end of the experimental period and after all data scoring, collation and entry were completed, the drug order code and serum cotinine concentrations were entered into the computer.
Of the eighteen subjects who began the study, fourteen subjects were considered to be tobacco abstinent using the biochemical markers of cigarette smoke exposure during the two abstinence periods. As a result, only the data from these fourteen individuals were included in the statistical analyses. The statistical analyses included a two within subjects factor repeated measures analysis of variance (Dose×Time) using SPSS for the microcomputer. Due to large expectancy effects which occurred at the end of the session, the two hour time point for all variables not included in the analyses. Statistical significance was defined as a p-value equal to or less than a five percent probability of a chance occurrence.
E. Results
Eighteen male cigarette smokers who were required to be abstinent prior to receiving the drug infusions in sessions 3 and 5 participated. Upon receipt of the serum cotinine concentration data, four subjects were found not to be abstinent from cigarette smoking during the abstinence phases. Their data was excluded from subsequent statistical analyses. Of the four data sets removed, two received drug first and two received placebo first maintaining the counterbalanced-order design. The data presented herein represent those collected from the 14 study-compliant completing participants.
The participants were healthy male cigarette smokers whose average age was 25.6 years (SD=6.5). None of the participants were interested in cigarette smoking cessation. They smoked an average of 25.4 (SD=6.0) cigarettes per day. Their average expired-air carbon monoxide concentration was 9.1 (SD=7.3). Their average expressed-air carbon monoxide concentration was 28.1 ppm (SD=10.3). The average FTC estimated nicotine yield of their cigarettes was 0.87 (SD=0.3). Their average baseline serum cotinine concentration was 378 (SD=16.3). Their mean education level was 14.5 years (SD=1.7).
TABLE 1__________________________________________________________________________Biochemical Measures Cotinine Placebo DifferenceVariable Mean (SE) Mean (SE) Mean (SE) T-SCORE P-VALUE__________________________________________________________________________Serum Cotinine 430 (26) -11 (2.3) 441 (27) 16.4 .001Concentration(session change)Serum Nicotine 0.1 (0.1) 0.0 (0.1) 0.1 (0.2) 0.6 nsConcentration(session change)__________________________________________________________________________ ns = nonsignificant
The average baseline serum cotinine concentrations for the sessions were as follows (ng/ml): Session 2: 378 (SE=43) Session 3: 48 (SE=5.8); Session 4: 308 (SE=24); and Session 5: 54 (SE=6.7). The average baseline serum nicotine concentrations (ng/ml) for sessions 3 and 5 were 0.4 (SE=0.2) and 0.2 (SE=0.2), respectively. In Table 1, the sessional changes in serum cotinine and nicotine concentrations are listed. These values represent the session end minus session beginning concentrations. Serum cotinine concentration increased by 430 ng/ml of serum in the cotinine condition and decreased 11 ng/ml in the placebo condition (T(13)=16.4; p=0.001). More importantly, the serum nicotine concentration showed no change during the session which rules out the possibility of unanticipated nicotine administration as the agent responsible for the reported subjective effects in this experiment. The observed change in nicotine concentration was consistent with the limits of sensitivity of the analyses.
TABLE 2__________________________________________________________________________SUBJECTIVE MEASURES 0 min 5 min 15 min 30 min 60 min Mean Mean Mean Mean Mean Dose Time Dose × TimeVariable (SE) (SE) (SE) (SE) (SE) p-value p-value p-value__________________________________________________________________________SEDATED (VAS)Cotinine 26 28 27 30 27 .03 .07 ns (6) (6) (5) (6) (4)Placebo 24 33 42 40 37 (3) (5) (7) (7) (7)RESTLESS (WSC)Cotinine 3.1 1.4 1.4 1.6 1.8 .05 ns ns (.3) (.3) (.3) (.4) (.4)Placebo 2.6 0.9 0.9 0.9 0.9 (.4) (.2) (.2) (.2) (.3)RESTLESSNESS (AEQ)Cotinine 1.8 1.2 1.2 1.4 1.4 .05 .001 ns (.2) (.1) (.1) (.1) (.2)Placebo 1.9 1.0 1.0 1.1 1.0 (.2) (.0) (.0) (.1) (.0)INSOMNIA (WSC)Cotinine 1.2 0.1 0.1 0.1 0.1 .02 .01 .02 (.3) (.1) (.1) (.1) (.1)Placebo 0.6 0.1 0.0 0.0 0.0 (.3) (.1) (0) (0) (0)VIGOR (VAS)Cotinine 16 13 11 7 7 .05 .01 ns (9) (6) (5) (5) (7)Placebo 28 9 -6 -3 (6) 10) (7) (8) (6)PLEASANT (VAS)Cotinine 41 49 46 45 44 .05 .05 ns (3) (4) (4) (5) (5)Placebo 44 53 55 50 51 (3) (3) (4) (4) (4)ANXIOUS/TENSE (WSC)Cotinine 3.2 2.1 1.8 1.7 2.1 .05 ns ns (.4) (.4) (.3) (.3) (.4)Placebo 2.9 1.1 1.3 1.2 1.0 (.4) (.2) (.3) (.2) (.2)TENSION/ANXIETY (POMS)Cotinine 17 10 10 .05 .001 ns (2) (1) (2)Placebo 14 6 6 (2) (1) (1)__________________________________________________________________________ ns = nonsignificant
Intravenous cotinine base administration compared to placebo had no effect on heart rate, blood pressure or the ECG intervals (e.g., PR, QRS and QT). In Table 2, the subjective ratings of mood and cigarette withdrawal symptoms are listed. Throughout the study, subjects rated themselves as feeling less pleasant (p=0.05) and sedated (P=0.03), while simultaneously reporting feeling increased vigor (p=0.05), anxious/tense (p=0.05), tension/anxiety (p=0.05), restless (p 0.05), restlessness (p=0.05) and insomnia (p=0.02) as function of cotinine administration. The feelings of tension/anxiety and restlessness were rated on different instruments showing some degree of reliability for these measures.
The statistical analyses performed on the various measures of craving using data from both experimental sessions yielded no significant differences. This was likely due to immense variability generated by the subjects in the third session. Therefore, to examine the effects of cotinine on craving, a reanalysis of the data comparing cotinine versus placebo on the maximum sessional decrease from baseline for the various craving measures was performed using only session 5 data. The results are summarized in Table 3. The "Craving for Tobacco" visual analog score (p=0.02) and the average of all craving scales (p=0.05) were significantly decreased in the cotinine condition as compared to placebo. The average of all craving scores was achieved using the WSC "craving for nicotine" score multiplied by 20 and then adding all of the scores and dividing this total by four. There was a consistent directional effect across all measures with the cotinine showing a greater influence than placebo.
TABLE 3__________________________________________________________________________Maximum Craving Decrease Scores Cotinine Placebo DifferenceVariable Mean (SE) Mean (SE) Mean (SE) T-SCORE P-VALUE__________________________________________________________________________Need for -24.8 (6.3) -13.7 (2.7) -11.1 (6.8) -1.63 0.07Cigarettes(VAS-1)Craving for -19.6 (4.7) -16.3 (2.7) -3.3 (5.5) -0.59 nsCigarettes(VAS-1)Craving for -25.6 (3.8) -14.3 (3.1) -11.3 (4.8) -2.33 0.02Tobacco(VAS-2)Craving for -1.56 (.18) -1.11 (.26) -0.45 (.32) -1.41 0.09Nicotine(WSC)Average of All -24.9 (2.8) -17.4 (3.2) -7.5 (4.2) -1.77 0.05Craving Scales(VAS-1,-2,WSC)__________________________________________________________________________ ns = nonsignificant
In Table 4, various measures of appetite are presented. The repeated measures analysis of variance showed a trend towards significance, however it was not significant. 14 of 18 participants showed a minimal to large effect with cotinine decreasing self-reported ratings of hunger (Sign test; p<0.05). As a result, a two within subject factor repeated measures analysis of variance was performed on these 14 individuals. The subjects reported feeling significantly less hungry during the cotinine session when compared to placebo (p<0.001). While no significant difference was found for ratings of excessive hunger, there was a similar trend in these individuals. No difference was observed for increased eating. The average hunger score was derived by using the weighted average of excessive hunger (excessive hunger×20) added to the rating of hungry. The average hunger rating was significantly decreased in the cotinine condition as opposed to placebo (p<0.02).
TABLE 4__________________________________________________________________________HUNGER SCORES 0 min 5 min 15 min 30 min 60 min Mean Mean Mean Mean Mean Dose Time Dose × TimeVariable (SE) (SE) (SE) (SE) (SE) p-value p-value p-value__________________________________________________________________________HUNGRYCotinine 34 27 21 26 35 .001 .06 ns (5) (5) (3) (5) (6)Placebo 42 36 41 39 43 (6) (6) (6) (6) (6)EXCESSIVE HUNGERCotinine 0.8 0.3 0.5 0.6 1.0 ns .03 ns (.2) (.1) (.2) (.2) (.3)Placebo 1.2 0.7 0.6 0.9 1.2 (.4) (.3) (.3) (.4) (.4)INCREASED EATINGCotinine 1.4 0.2 0.2 0.3 0.3 ns .001 ns (.3) (.1) (.2) (.2) (.2)Placebo 1.1 0.2 0.2 0.1 0.2 (.4) (.1) (.1) (.1) (.1)TOTAL HUNGER SCORECotinine 47 33 31 39 55 .02 .007 ns (9) (6) (7) (9) (11)Placebo 67 50 54 57 67 (11) (10) (10) (13) (13)__________________________________________________________________________ ns = nonsignificant
G. Discussion
The purpose of the study was to determine whether an intravenously administered nicotine metabolite (cotinine base) has significant psychoactivity in abstinent tobacco users. The data presented herein is the first demonstration that a nicotine metabolite is pharmacologically-active and produces many subjective changes in humans without affecting cardiovascular activity. Further, while cotinine administration appeared to exacerbate certain symptoms of the tobacco withdrawal syndrome including restlessness and anxiety/tension, it simultaneously attenuated other withdrawal symptoms including sedation and the various craving measures (for tobacco, nicotine and cigarettes) experienced during the session. Also, the subjective profile of cotinine base following intravenous administration is consistent with the activity of a psychomotor stimulant.
Other findings reported herein suggest that a nicotine metabolite, cotinine, may serve to act as an appetite suppressant and could be responsible in part for the decreased body weight of tobacco users. The data suggest that cotinine is a psychomotor stimulant and its ability to suppress appetite probably stems from this activity. Acutely, people using psychomotor stimulants typically report more anxiety, tension, insomnia, irritability, restlessness and less sedated until they become tolerant to these effects. Also, psychomotor stimulants typically are used as appetite suppressants (e.g., phentermine, phenmetrazine, amphetamine, fenfluramine, diethylproprion). Nicotine has been shown to increase resting metabolism and decrease perceived taste intensity of various foods in nicotine-experienced and nicotine-naive individuals suggesting a mechanism by which this drug exerts its effects. If nicotine and its metabolites act through the same mechanism, then they should act similarly in nicotine-experienced, nicotine-abstinent or nicotine-naive individuals.
All publications and patent applications mentioned in this specification are indicative of the level of ordinary skill in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
It will be apparent to one of ordinary skill in the art that many changes and modifications can be made in the invention without departing from the spirit or scope of the appended claims. | A therapeutic method is provided to alleviate the tobacco withdrawal syndrome, the symptoms of nicotine withdrawal or the management of human body weight in nicotine-experienced or nicotine-naive individuals, comprising of administering an amount of nicotine metabolites or a pharmaceutically acceptable salts thereof to a human in need of such treatment, in an amount which is effective to reduce or eliminate at least one of the symptoms of the tobacco withdrawal syndrome, nicotine withdrawal or manage human body weight. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the packaging of electronic assemblies, and more particularly to a construction and method of encapsulating electronic circuits wherein the encapsulating medium is easily removable for reworking or repair of the electronic system.
2. Description of the Prior Art
It is desirable when sensitive electronic circuitry are exposed to an environment of shock and vibration to protect the electronic assembly from damage induced by excessive forces applied to the components. Further, in operation such assemblies generate heat, which must be dissipated. Accordingly, past practice has provided for encapsulating the electronic components to prevent failure due to the effects of mechanical shock and vibration, and further to enhance transfer of heat from the assembly to an external heat sink.
The prior art has utilized rigid epoxies and foamed polyurethanes as encapsulants, with varying degrees of success. When an assembly is encapsulated or potted with epoxy and cured to a rigid state, effective protection to shock and vibration is provided by limiting excessive motion of the circuit boards and electrical components. However, when an assembly is rigidly encapsulated, repairs and circuit modifications are extremely difficult to accomplish, making such repairs frequently uneconomical or permitting damage to the circuit board and components, and resulting consequently in a "throwaway" assembly. The rigid material creates a "brick" which cannot practically be reentered. This prohibits failure analysis and replacement of failed circuits. In addition, the rigid material may cause mechanical failures due to differences in thermal coefficients of expansion between the encapsulant and the circuit elements. High voltage power supplies are particularly sensitive to manufacturing variances, increased capacitances, higher operating losses, and the resultant higher temperatures. DC to DC converters obtain power from an input source and convert it into regulated output power at higher or lower voltages for delivery to a load. Typically, for energizing a cathode ray tube, a voltage of the order of 25 kv may be required. However, not all of the input power is converted to output power, since the supply is not 100% efficient, and some power is dissipated as heat within the converter. Thus, the encapsulant must not hinder heat transfer, and preferably will enhance heat removal from the heat generating components into the surrounding environment. In one program, it was estimated that the cost of scrapping rigidly potted power supplies as opposed to accomplishing repair amount to upwards of $500,000.00 per year.
Another approach has been to encapsulate sensitive assemblies in a substantially rigid, shock absorbing polyurethane foam, which is accomplished by placing the reactive chemicals into an enclosure with the electronic assembly, which reacts to form a foam that fills the spaces between individual components and between the components and the housing. However, the foam has been found to act as an adhesive which bonds the components tightly into the assembly, thus making removal of components for repair very difficult and time consuming.
Liquid insulating fillers, such as oils and fluorinated fluids have been use, but require seals and bellows or other techniques to allow for liquid expansion and may penetrate and adversely affect component performance. Introducing an inert gas or evacuating the assembly housing requires hermetic seals, rigid mechanical component support provisions, and sophisticated means for heat dissipation. It has been found in testing that a ferrite core transformer, rigidly potted as a module, failed when encapsulated in silicone gel or RTV media. While said transformer functioned satisfactorily when encapsulated in a rigid medium, when encapsulated in the gel or RTV the transformer failed due to internal heating, which caused expansion of the transformer and fracture of the module potting. This was attributed to lack of physical support by the compliant media. The problem was exacerbated by poor thermal conductivity of the silicone gel. It was therefore found necessary to increase the thickness of the rigid module potting, which occupied additional space and added weight.
It is clear then that a need exists for an improved encapsulant and method of application which is effective in significantly reducing or eliminating the effects of vibration and shock on circuit components, while facilitating heat dissipation, and yet which may easily be removed from the components to permit them to be tested, serviced, modified, or otherwise processed with ease. A reworkable encapsulant in place of the above described encapsulating media will reduce costs by allowing modules to be reworked instead of scrapped, and cost effective failure analysis would be possible in view of the ease of entry into the module without disturbing the circuit elements. Ease of rework promotes reliability improvements by permitting discovery of the failure modes. Finally, production would be enhanced because elaborate component protection schemes now required with rigid encapsulants would not be required.
SUMMARY OF THE INVENTION
The present invention provides for encapsulating an electronic assembly with an elastic medium that provides support against shock and vibration, while enhancing heat transfer to the surroundings and permitting efficient, economical removal of the encapsulant for rework. Refilling the assembly enclosure after inspection and repairs is facilitated by a tool that provides for selectively applying the encapsulant to the circuit components while constraining the housing against overfilling.
A preferred embodiment of the invention comprises a generally rectangular housing open at its top and bottom boundaries, having a flexible wall defining arcuate interior corners, for accommodating deflection induced by thermal expansion of an encapsulating medium disposed therein. A removable planar top cover is secured to a top surface of the housing, and a removable planar bottom cover is secured to a bottom surface of the housing. A circuit board supporting a plurality of electronic components mounted thereupon is resiliently disposed within the housing. The encapsulating medium is preferably thermally conductive and has a predetermined thermal coefficient of expansion compatible with that of the electronic components and the flexible wall of the housing, so that expansion of the medium with increased temperature results in only temporary minimal deflection of the wall, while return to ambient temperature results in the wall resuming its original configuration, the medium substantially filling the space defined by the housing and surrounding the circuit board, while the circuit board is relatively resiliently constrained with respect to the housing with expansion and contraction of the medium, so that stress applied to the electronic components is minimized.
The encapsulating medium is a silicone elastomer having a density when cured for resiliently securing the circuit board and electronic components from shock and vibration, while its thermally conductive properties allow dissipation of heat generated by the components through the medium to the housing, the medium further having a density allowing removal with a razor-edged cutting tool so as to permit exposing the electronic components for test and repair.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a conceptual exploded view of a reworkable encapsulated electronic assembly of the present invention, with the encapsulant removed to show a printed circuit board mounted therein.
FIGS. 2 and 3 are graphs of component displacement due to expansion of the encapsulant as a function of temperature.
FIG. 4 is a perspective view of a potting tool used for selectively applying encapsulant to a reworked electronic assembly.
FIG. 5 is a perspective view showing the structure of the potting tool with a portion of the tool removed for clarity.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A preferred embodiment is shown in the drawings, wherein like reference numerals designate like or corresponding elements. Referring now to FIG. 1 of the drawings, an electronic assembly 10 is depicted in an exploded view. As shown, the assembly includes a substantially rectangular housing 12 defining planar top and bottom faces 14 and 16, respectively. The housing 12 is comprised preferably of aluminum, and may be machined from a solid block or fabricated from sheet metal pieces welded together. The housing has a wall thickness of approximately 0.050 inch.
Disposed within housing 12 is a conventional double sided printed circuit board 18 which is generally rectangular in configuration, and is supported within housing 12 by a plurality of flanges 20 substantially symmetrically disposed along the walls 22, 24, 26, 28 and proximal to bottom face 16. Housing 12 is also provided with a plurality of tapped flanges 30 for securing top and bottom plates 32, 34. The top and bottom plates are substantially rectangular and planar, conforming to the peripheral contours of housing 12. Housing 12 is further fabricated with arcuate corners 36, which impart structural rigidity while allowing deflection of walls 22, 24, 26, 28 in accordance with temperature variations of the assembly in operation. Housing 12 is further provided with a plurality of mounting flanges 38 for securing the assembly in its intended environment.
Printed circuit board 18 may be a conventional double-sided glass epoxy circuit board which has copper conductive traces formed top and bottom (not shown in FIG. 1). Note that board 18 is shown in exploded disposition relative to housing 12 and normally rests upon and is supported within housing 12 by the flanges 20, where it will be resiliently confined by the encapsulating medium 19. This allows board 18 to accommodate expansion and contraction of the encapsulant and housing 12 without distortion or cracking of the traces, and without imposing stress on the electronic components mounted thereupon.
Positioned on board 18 are a variety of electronic components. The electronic components can assume a wide variety of different configurations, depending upon the type and size of individual components which are required in the electronic circuitry of the PC board subassembly. That is, small or large discrete components, such as capacitors, transistors, and transformers may be used, or the components may be circuit cards or microelectronic circuits. In a typical approach, shown in FIG. 1 (not to scale), a high voltage capacitor divider may be represented by a plurality of capacitors 40 measuring 0.6 in×0.6 in or by a capacitor stack 42 measuring 0.75×1.10 in, and a ferrite core transformer by dimensions 1.43 ×1.24×0.990 in. Semiconductors are typically 0.10 diam×0.5 in for diodes and 0.20 diam×0.15 in for transistors, while resistors range from 0.60 diam×0.30 in for low wattage types to 0.20 diam×2.2 in for high voltage types.
In order to facilitate rework, the PC board 18 is provided with strategically placed holes 44 or "pushouts" under selected components to allow later removal without the necessity of removing the PC board in its entirety, and to reduce encapsulant voids during the potting process.
As discussed above, the problem solved by the present invention is how to select and apply an encapsulant to an electronic assembly in a manner that provides protection against temperature extremes, humidity, dust, shock and vibration, and affords a substantial degree of thermal conductivity without causing structural impairment or degradation of electrical performance, and of a nature that permits selective removal of portions of the encapsulant and ready rework of the assembly components. The problem is essentially threefold: firstly, encapsulants as a class have different thermal coefficients of expansion than most electrical components, rendering them unsuitable for use in close contact with these electrical components. Secondly, while rigid encapsulants offer suitable properties with respect to mechanically securing the electronic components with minimal effect on performance, they render a defective assembly unsalvageable, as it cannot practicably be reworked. Thirdly, the encapsulant must have sufficient electrical inertness that the electrical performance of the assembly is not degraded, even when exposed to high potential, high frequency applications.
In selecting the material used to form the reworkable encapsulant, careful consideration must be given to the physical, chemical and electrical properties if it is to be successful as an encapsulant which retains its properties without damage to the electronic assembly over a wide range of operating conditions. The encapsulant material must be chemically inert and must not decompose or initiate corrosion. It should have a reasonable long shelf life. It must be insensitive to wide temperature ranges and maintain its properties at both high and low temperatures. It must be a good vibration damper and must be able to minimize the motion of components over a wide frequency and amplitude range. The compound should be electrically inert and must not affect or influence circuit operation. This requires a high dielectric strength, low dielectric constant, high insulation breakdown voltage, high resistivity, and a low dissipation factor.
A material survey was undertaken to identify suitable candidates for the encapsulant, with typical circuit components applied to a conventional two-sided printed wiring board. From approximately 60 materials that were believed to meet the criteria, the best 12 materials were chosen for testing. These tests were initially directed to quantify critical electrical parameters required for high voltage applications, as follows:
a. dielectric withstanding voltage of the bulk material.
b. dielectric withstanding voltage at the material and substrate interface.
c. insulation resistance at the material and substrate interface.
Power supplies operating at 25 kv demand materials with high dielectric strength. Improved dielectric strength allows sufficient derating for reliability and still permits compact, advanced packaging. Dielectric strength was tested in a bulk condition (through the potting material) and in an interfacial condition (at the interface of the encapsulant and the printed circuit board). The key mechanical tests included the following:
a. definition of absolute shear strength.
b. observation of adhesion failure mode.
c. determination of 25 percent minimum elongation.
Each of these tests was run on control samples and for samples subjected to the environmental screening. Results from these tests and from a computer modelling evaluation were used to select the four most favorable candidates. These encapsulants were in the family of silicone elastomers, both filled and unfilled. A rigid epoxy and flexible epoxy were also tested, as well as a urethane compound. The epoxy was rated unacceptable due to insufficient elongation, even though it provided the best adhesive strength. A minimum elongation of 25 percent is necessary to allow for differences in thermal coefficient of expansion between the encapsulant and the electrical components. A cohesive failure mode (separation of the encapsulant) shows balance between the material strength and adhesion and suggest that processing and substrate preparation are sufficient. Adhesive failure, i.e., failure at the material and substrate interface, is undesirable, even if under high stress conditions. Such failure suggests that the material movement predicted by the computer model cannot take place without loss of adhesion and damage to the components. A combination of sufficient adhesive strength to transfer stress to the material rather than the bond and good elongation is most desirable.
Shear testing was performed on a control sample and after thermal cycling. Electrical tests were performed on control samples, after thermal cycling, a rework procedure, and humidity testing. All test were performed after a variety of realistic environmental stresses. Performance was remeasured after rework was initiated. A repeat of acceptable performance indicates that supplies are truly reworked to original performance levels. Finally, the ability of a material to be reworked was judged using an objective qualitative ranking system. The soft silicone gel was found to be unmanageable and along with the urethane, which was found to be too tough to rework, were eliminated after this performance rating. The flexible epoxy was highly moisture absorbent and also eliminated.
Practice has shown that potting with a rigid material in a rigid container may permit thermal stresses as high as 13,000 psi with resultant component damage. Silicone materials do not create such high degrees of stress, and with suitable component selection and lead strain relief will not create stress problems. However, silicone encapsulants inherently have a high thermal coefficient of expansion. During thermal cycling of sample packaged electronic assemblies failure was experienced of cracking of high voltage transformers due to the thin exterior wall construction of the transformer. Cracking was especially prominent in unfilled silicones due to their reduced heat dissipation capability. It was determined that soft silicone does not provide sufficient back pressure to accommodate the thermal expansion of the encapsulant. Therefore, a thicker transformer wall was required. Further relief from expansion stress was obtained by constructing the housing of thin wall material, to allow flexing when stressed, thus relieving the stress on the components, while forming the corners of the housing in arcuate fashion to retain structural integrity of the case.
FIGS. 2 and 3 show experimental plots of component deflection versus temperature for the selected encapsulant.
A commercially available product that has been found to possess the aforementioned essential properties is CASTALL S-1307, manufactured by Castall, Inc. of East Weymouth, Mass. It is a primerless, high molecular weight, heat curable silicone resin composition convertible when cured to an elastomer. It is compounded from a two-part system, part A comprised of a polydimethylsiloxane resin and part B comprised of a polymethylhydrogensiloxane catalyst mixed in a ratio of 1:1 by weight. Among the significant properties are good thermal conductivity (0.0034 cal/s/cm 2 /° C./cm), low temperature coefficient of expansion (137 ppm/° C.) and relative firmness (75 Shore A).
Turning now to FIGS. 4 and 5 of the drawings, there is shown a potting tool 50 to facilitate selective filling of the housing after portions of the encapsulant have been removed, as by a razor-edged tool. Tool 50 is provided with a plurality of holes 52 for mounting to corresponding tapped flanges 30 of housing 12, and a plurality of cylindrical collars 54 mounted over resin influx openings which are disposed over selected component areas of the printed circuit board 18. Tool 50 is provided with a clamp assembly 58 which engages a connector on the circuit board (not shown), thereby to assist alignment and preclude inflow of encapsulant into the connector area. The baseplate 60 is accordingly provided with a slot 62 for accepting the clamp 58.
For rework, the top and bottom covers are removed, and a portion of the encapsulant over a suspect component area is excised with a razor-edged tool, such as the commonly found Xacto® knife. Tests are performed on the circuit board test points, as required to identify the failed component, which is then replaced by procedures well known to those skilled in the art, utilizing the pushouts as necessary for access, and the assembly is retested for proper operation. The potting tool 50 is then secured to housing 12 in place of the top cover and the bottom cover secured to the housing. The encapsulant is then compounded and applied through selected ones of the cylindrical openings 54. Since the openings are in fluid communication with and the potting compound is chemically and physically compatible with the silicone elastomer within the housing 12, the excised portion of encapsulant is readily and efficiently refilled. The module with potting tool is then evacuated. After completion of the vacuum pour cycle the module is placed in an oven to be cured preferably for at least 16 hours at an elevated temperature of 85° C. The potting tool is then removed, the pour spouts cut off, and the top cover secured to the module. Since an elevated temperature is required for cure, no interference between the top cover and the encapsulant will be encountered, since the encapsulant contracts as it cools down. While the tool 50 has been adapted for application to the top surface of circuit board 18 which bears an electrical connector, a similar structure may be used for accomplishing refill access through the bottom of housing 12. However, in practice, it is usually necessary to access both top and bottom of the module, so that refill from the top is generally all that is required.
While the invention has been described in its preferred embodiment, it is to be understood that the words which have been used are words of description rather than of limitation and that changes within the purview of the amended claims may be made without departing from the true scope and spirit of the invention in its broader aspects. | An improved encapsulant and method of application for rework of a modular electronic assembly. A housing is provided with a structure that permits deformation with thermal expansion of the encapsulant and reduces stresses applied to the electronic components therewithin. The selected encapsulant provides mechanical stability from shock and vibration, thermal conductivity to the surroundings, and freedom from deterioration of electrical performance. Critically, the encapsulant is readily excised for repair and replacement of defective components, thus allowing rework and salvage of the assembly. A potting tool is adapted for selectively refilling the housing to replace the excised portions. |
BACKGROUND OF THE PRESENT INVENTION
1. Field of the Invention
This invention relates to a composite article comprising randomly or regularly arrayed oriented microstructures partially encapsulated within a layer, in particular to the method of making the same and to the use of the composite article as an electrically conducting polymer, thin film resonant circuit, antenna, microelectrode or resistive heater, and as a multimode sensor to detect the presence of vapors, gases, or liquid analytes.
2. Background Art
Composite articles containing or exhibiting a layered structure have been prepared by many different types of chemical and physical deposition processes.
For example, U.S. Pat. No. 4,812,352 discloses an article comprising a substrate having a microlayer (microstructured-layer) that comprises uniformly oriented, crystalline, solid, organic microstructures, several tens of nanometers in cross-section and a method of making the same. Further, '352 teaches optionally conformal coating the microlayer and encapsulating the conformal-coated microlayer.
Dirks et al. in "Columnar Microstructures in Vapor-Deposited Thin Films,"Thin Solid films, vol. 47, (1977), pgs 219-33 review several methods known in the art that can yield columnar microstructures, however, as Dirks et al. point out the structures are not a desirable or a sought-after outcome of vapor-deposition.
U.S. Pat. No. 3,969,545 describes a vacuum deposition technique that can produce organic or inorganic microstructures.
Floro et al. in "Ion-Bombardment-Induced Whisker Formation of Graphite," J. Vac. Sci. Technol. A. vol. 1, no. 3, July/September (1983) pgs 1398-1402 describe graphite whisker-like structures produced by an ion-bombardment process.
Flexible conducting media known in the art, typically having a layered structure, exist in a variety of distinct formats. For example, U.S. Pat. No. 4,674,320 discloses a conducting powder-like material, such as carbon, dispersed throughout a polymeric binder at concentrations sufficient to enable conduction by charge transfer from particle to particle. Such an arrangement results in an isotropicly conducting sheet, that is, resistivity perpendicular to the plane of the sheet is the same as the in-plane resistivity.
Bartlett et al., Sensors and Actuators, vol. 20, pg 287, 1989, disclose a conductive polymer film made by electrochemical polymerization. Resistivities of these polymer films are three-dimensionally isotropic and tend to be relatively high.
Other examples known in the art teach an article comprising a conducting layer applied to a flexible polymer sheet by vacuum coating processes, electrochemical or electroless plating processes, printing, particle embedding and the like. However, in these cases, the conductive coating, for example, a solid metallic layer, will have a low resistivity and is not easily controllable. Additionally, since the conductive layer is on the surface of a polymer substrate, adhesion of the conductive layer to the polymer substrate is often a problem. The adhesion problem is particularly apparent when the conducting layer is carrying current. If a very thin or discontinuous conductive layer is applied to the polymer substrate to increase the surface resistivity, the power carrying capability of the conductive layer tends to be compromised and the problem of adhesion tends to be exacerbated.
Electrical properties are useful as sensors, however, most prior art gas and vapor sensors are based on many of the prior art layered structures. The sensor media can be thin or thick film devices utilizing either surface acoustic wave (SAW) technology or chemiresistors incorporating solid electrolytes, polymers with bulk gas sensitivity, metal or semiconductor (inorganic or organic) thin films, or homogeneous dispersions of conducting particles in insulating matrices.
Generally, sensors based on SAW technology are costly to manufacture and tend to be used only for reversible sensing. They are generally not used for nonreversible sensors, such as dosimetry monitoring, see Snow et al., "Synthesis and Evaluation of Hexafluorodimethyl carbinol Functionalized Polymers as SAW Microsensor Coatings," Polymer Reprints, 30(2), 213 (1989); Katritzky et al., "The Development of New Microsensor Coatings and a Short Survey of Microsensor Technology," Analytical Chemistry 21(2), 83 (1989).
On the other hand, chemiresistor based sensors tend to be reversible or nonreversible depending on the chemical and physical composition of the sensing medium, see Katritzky et al., "New Sensor Coatings for the Detection of Atmospheric Contaminants and Water," Review of Heteroatom Chemistry, 3, 160 (1990). Generally, the prior art sensing media exhibit isotropic or homogeneous gas sensing properties. Media having an isotropic sensing property display the same resistivity in all directions of the media. Such media are typically capable of only a single mode of detection. In contrast, media having an anisotropic impedance sensing property display different in-plane and out-of-plane gas sensing impedances. Thus, anisotropic media permit multi-mode operation.
Generally, conduction through chemiresistor devices occurs between conducting particles dispersed throughout the media. For example, U.S Pat. No. 4,674,320 teaches a chemiresistive gas sensor comprising a layer of organic semiconductor disposed between two electrodes, wherein dispersed within the layer of organic semiconductor is a high conductivity material in the form of very small particles, or islands. Adsorption of a gaseous contaminant onto the layer of organic semiconductor or modulates the tunneling current.
U.S. Pat. No. 4,631,952 discloses an apparatus and a method for sensing organic liquids, vapors, and gases that includes a resistivity sensor means comprising an admixture of conductive particles and a material capable of swelling in the presence of the liquid, gas, or vapor contaminant.
Ruschau et al., "0-3 Ceramic/Polymer Composite Chemical Sensors," Sensors and Actuators, vol. 20, pgs 269-75, (1989) discloses a composite article consisting of carbon black and vanadium oxide conductive fillers in polyethylene, a polyurethane, and polyvinyl alcohol for use as chemical sensors. The polymer matrices swell reversibly in the presence of liquid and gaseous solvents, disrupting the conductive pathway and proportionally increasing the resistance.
U.S. Pat. No. 4,224,595 discloses an adsorbing type sensor having electrically conductive particles embedded in a surface, forming an electrically conductive path through the sensor.
U.S. Pat. No. 4,313,338 discloses a gas sensing device comprising a gas sensing element comprising a gas-sensitive resistive film formed of an aggregate of ultrafine particles of a suitable material deposited on the surface of a substrate of an electrical insulator formed with electrodes.
U.S. Pat. No. 3,820,958 discloses an apparatus and a method for determining the presence of hydrogen sulfide in a gas mixture. Silver is deposited on a thin dielectric film. Electrical resistance across the film before and after exposure of the film to hydrogen sulfide containing gas mixture is utilized to determine the amount of hydrogen sulfide present.
U.S. Pat. No. 4,906,440 discloses a sensor for a gas detector comprising a metallic/metallic oxide gas sensitive discontinuous film. The gas changes the conductivity of the film and causes the RC network to react.
U.S. Pat. No. 3,045,198 discloses a detection device comprising an electrical element sensitive to exposure to liquids, vapors or gases. The detection element includes a broad and long base having an electrically non-conductive, relatively resilient surface on which is anchored a stratum of exposed electrically conductive discrete adsorbent particles.
Sadaoka et al., Effects of Morphology on NO 2 Detection in Air at Room Temperature with Phthalocyanine Thin Films," J. of Mat'l Sci. 25, 5257 (1990) disclose that crystal size in films is affected by the nature of the substrate, ambient atmosphere, and annealing time. The variations of the crystals can effect the detection of NO 2 in air.
SUMMARY OF THE PRESENT INVENTION
Briefly, this invention provides a composite article with an electrically conductive surface comprising a layer having a dense array of discrete, oriented microstructures partially encapsulated and optionally having a conformal coating wherein one end of the microstructures is exposed and coincident with the conductive surface. The conformal coating, preferably is a conducting material. The encapsulant, is preferably a dielectric. Advantageously, the anisotropic structure of the composite article provides anisotropic impedance, that is, the impedance parallel to the surface plane of the composite article is resistive, while the impedance perpendicular to the surface plane of the article is predominantly capacitive.
In another aspect, a resonant circuit is described wherein the composite article provides the resistive (R) and capacitive (C) component of the circuit. Advantageously, the resonant circuit can be constructed as a low-pass filter, a high-pass filter, a band-pass filter and the like. Furthermore, the composite article can be fabricated such that the conducting layer is formed in patterns suitable for building electronic circuits. This is achieved, by depositing the crystalline microstructures in patterns, or conformally coating the microstructures through a mask, or by encapsulating the coated microstructures through a mask, or by any combination of the above.
In yet another aspect of the present invention, a multimode sensor is described. The unique construction of the composite article enables selection of the conformal coating and the encapsulant for their responses to a particular analyte molecule of interest. The effect of gas/vapor/liquid molecules on the multimode sensor is detected by monitoring the changes in the composite article's electrical properties, that is the resistance and the capacitance.
In this application:
"whisker-like structure" refers to individual repeating units such as, for example, material structures, whiskers, rods, cones, cylinders, laths, pyramids and other regular or irregular geometric shaped structures;
"microstructure" refers to the whisker-like structure that has been conformally coated;
"microstructured-layer" refers to a layer formed by all the microstructures taken together;
"conformal-coated" means a material is deposited onto the sides and an end of each whisker-like structure element to envelope the element such that the deposited material conforms to the shape of the whisker-like structure element;
"uniformly oriented" means the microstructures are approximately perpendicular to the surface of the substrate;
"solidified" means the encapsulant undergoes a change in state, typically from a liquid or liquid-like phase to a more rigid, solid, or solid-like phase, such as may occur as a result of drying, chemical setting, cooling, freezing, gelling, polymerization, etc.;
"continuous" means coverage of a surface without interruption of the coating;
"discontinuous" means coverage of a surface wherein there is periodic or non-periodic interruption of the coating;
"uniform" with respect to size, means that the major dimension of the cross-section of the individual microstructures varies no more than about ±25% from the mean value of the major dimension and the minor dimension of the cross-section of the individual microstructures varies no more than about ±25% from the mean value of the minor dimension;
"areal number density" means the number of microstructures per unit area;
"gas" means a state of matter existing in the gaseous state at standard temperature and pressure, but can be liquified by pressure; and
"vapor" means an air dispersion of molecules of a substance that is liquid or solid in its normal state, that is at standard temperature and pressure, sometimes called fumes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a perspective view of an article with a nanostructured composite surface being delaminated from a substrate according to the present invention with a cut away portion showing the composite whisker-like structures.
FIGS. 2 (a) and (b) illustrate a three terminal AC electric circuit configuration using metal foil tape as one contact to the invention and its simplified representative RC schematics.
FIGS. 3 (a) and (b) illustrate two strips of nanostructured composite media, as shown in FIG. 1, adjacently positioned to form a four terminal network configuration and a simplified equivalent circuit.
FIGS. 4 (a) and (b) illustrate an alternative "series" configuration with band-pass characteristics and a simplified equivalent circuit.
FIG. 5 is the graphic representation of the low-pass AC filter transfer function measured for Examples 1 and 2.
FIG. 6 is the graphic representation of the three terminal network low-pass frequency response functions for Examples 3 to 10.
FIG. 7 is the graphic representation of the three terminal network high-pass frequency response function for Examples 3 to 10.
FIG. 8 is the graphic representation of the temperature rise of the nanostructured surface versus electrical power dissipated by the conducting layer of the composite media of Examples 20-23 of the present invention when the composite layer is heat-sinked (a to c), compared to a Co film sputtered onto polyimide.
FIGS. 9 (a) and (b) is the graphic representation of the resistance change of type B sample of Examples 24 and 31.
FIG. 10 is the graphic representation of the sensitivity versus exposure time for type C samples of Example 30.
FIG. 11 is the graphic representation of the resistance change versus time for type E samples of Example 32.
FIG. 12 is the graphic representation of the sensitivity versus time at several temperatures and vapor pressure fractions for type F samples of Example 34.
FIG. 13 is the graphic representation of the sensitivity versus time at several temperatures and vapor pressure fractions for type G samples of Example 35.
FIG. 14 is the graphic representation of the sensitivity versus time for saturated water vapor at several temperatures for type E samples of Example 36.
FIG. 15 is the graphic representation of the capacitance change versus time for B, E, L, and M type samples of Example 40.
FIG. 16 is an Arrhenius plot for the rate kinetics for water vapor oxidation of Cu coated whisker composite media of type E.
FIG. 17 is a graphic representation of the linear relationship of the sensor resistance changes versus the log of the initial resistivity, wherein the slope is ostensibly proportional to the analyte concentration.
FIG. 18 is a solid state diffusion model representation of sensitivity versus time data from FIG. 12.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention discloses a composite article having an electrically conducting surface, the process for making such a film with variable surface resistivity, and use of the invention as a flexible electric circuit element having both capacitance and resistance properties are described. Specific examples are given demonstrating the suitability of the media for use directly as passive RC filter networks with significant power dissipation potential. Additional examples demonstrate the suitability of the media for use as gas, vapor and liquid analyte sensors that derive sensing properties from the properties of the nanostructured composite film surface. The sensor functions uniquely in two distinct ways, first in terms of the dual mechanisms by which vapor/gas/liquid molecules affect sensor properties, and secondly with respect to the independent resistance and capacitance impedance properties that can be measured as a function of exposure to the vapor, gas, or liquid.
Referring to FIG. 1, composite article 20 comprises encapsulant layer 12, for example, a polymer that has encapsulated in layer 12 arrayed microstructures 16, which may also be composites preferably initially oriented normal to the substrate 11. Each microstructure 16 comprises whisker-like structure 14 and optionally, conformal coating 13 enveloping whisker-like structure 14. The chemical composition of microstructures 16 is determined by the starting material deposited on substrate 11 to form the whisker-like structures 14 and the conformal coating 13 subsequently applied to the whisker-like structures 14. Microstructures 16 may be randomly or regularly arrayed in encapsulating layer 12.
As shown in FIG. 1, composite article 20 is partially delaminated from substrate 11 and delamination of composite article 20 is occurring at interface 15. Delamination of the composite article 20 from substrate 11 takes microstructures 16 along, embedded precisely in the surface of encapsulant layer 12 and exposes one cross-sectional end of each microstructure 16, wherein a surface of the- encapsulating material of encapsulant layer 12 and the exposed cross-sectional ends of microstructures 16 are coincident on a common side. The topography of the delaminated surface, or exposed surface of the composite article 20 is the inverse of the topography of the surface of substrate 11 from which it is delaminated. Furthermore, the exposed surface of the composite article 20 is electrically reactive, that is, exhibits surface electronic phenomena, such as resistance and capacitance. If the surface of substrate 11 is perfectly smooth, the exposed cross-sectional ends of microstructures 16 and the delaminated surface of the encapsulating layer will be on a common plane.
The unique fracture and adhesion properties of whisker-like structures 14 at substrate interface 15 allow whisker-like structures 14 to withstand the coating and encapsulating processes, yet be easily and cleanly delaminated from substrate 11.
The thickness of conformal coating 13 applied to whisker-like structures 14, and intrinsic resistivity of said conformal coating 13, are the primary parameters controlling the surface electronic conductivity of composite article 20.
It should be noted that composite article 20 can have the conducting area formed into patterns suitable for building electronic circuits by several means. For example, starting material, for example, perylene pigment, can be deposited through a mask, or the conducting conformal coating can be applied to the whisker-like structures through a mask, or the encapsulant can be photolithographically applied to encapsulate the coated whisker-like structures image-wise. The small volume and flexibility of the medium of the present invention allows it to be used in a wide variety of resonant circuit constructions. Additionally, the exposed surface of the composite article, that is the reactive surface, can be coated in a patterned manner with an insulator or other dielectrics.
Materials useful as a substrate for the present invention include those which maintain their integrity at the temperatures and pressures imposed upon them during any deposition and annealing steps of subsequent materials applied to the substrate. The substrate may be flexible or rigid, planar or non-planar, convex, concave, aspheric or any combination thereof.
Preferred substrate materials include organic or inorganic materials, such as, polymers, metals, ceramics, glasses, semiconductors. Preferred organic substrates include polyimide film, commercially available under the trade designation KAPTON™ from DuPont Corp., Wilmington, Del. Additional examples of substrate materials appropriate for the present invention can be found in U.S. Pat. No. 4,812,352 and is incorporated herein by reference.
Starting materials useful in preparing the whisker-like structures include organic and inorganic compounds. The whisker-like structures are essentially a non-reactive or passive matrix for the subsequent conformal coating and encapsulating material. In addition to starting materials that produce whisker-like structures, several techniques or methods are useful for producing the whisker-like configuration of the particles.
For example, methods for making organic microstructured layers are disclosed in J Sci. Technol. A, vol. 5, no. 4, July/August (1987), pgs 1914-16; J. Sci. Technolol. A, vol. 6, no. 3, May/June (1988), pgs 1907-11; Thin Solid Films, vol. 186, (1990), pgs 327-47; U.S. Pat. No. 3,969,545; Rapid Quenched Metals, (Proc. of the Fifth Int'l Conf. on Rapidly Quenched Metals), Wurzburg, Germany, Sept. 3-7 (1984); S. Steeb et al. Eds. Elsevier Science Publishers B.V., New York (1985), pgs 1117-24; U.S. Pat. No. 4,568,598; Photo. Sci. and Eng., vol. 24, no. 4, July/August, (1980), pgs 211-16; and U.S. Pat. No. 4,340,276, the disclosures of which are incorporated herein by reference.
Methods for making inorganic-, metallic-, or semiconductor-based microstructured-layers or whisker-like structures are disclosed in U.S. Pat. No. 4,969,545; J. Vac. Sci. Tech. A, vol. 1, no. 3, July/Sept. (1983), pgs 1398-1402; U.S. Pat. No. 4,252,864; U.S. Pat. No. 4,396,643; U.S. Pat. No. 4,148,294; U.S. Pat. No. 4,155,781; and U.S. Pat No. 4,209,008, the disclosures of which are incorporated herein by reference.
The organic compounds include planar molecules comprising chains or rings over which π-electron density is extensively delocalized. These organic materials generally crystallize in a herringbone configuration. Preferred organic materials can be broadly classified as polynuclear aromatic hydrocarbons and heterocyclic aromatic compounds. Polynuclear aromatic hydrocarbons are described in Morrison and Boyd, Organic Chemistry 3rd ed., Allyn and Bacon, Inc. (Boston, 1974), Chap. 30. Heterocyclic aromatic compounds are described in Chap. 31 of the same reference.
Preferred polynuclear aromatic hydrocarbons include, for example, naphthalenes, phenanthrenes, perylenes, anthracenes, coronenes, and pyrenes. A preferred polynuclear aromatic hydrocarbon is N,N'-di(3,5-xylyl)perylene-3,4:9,10 bis(dicarboximide), commercially available under the trade designation of C. I. Pigment Red 149 (American Hoechst Corp., Sommerset, N.J.) [hereinafter referred to as perylene red].
Preferred heterocyclic aromatic compounds include, for example, phthalocyanines, porphyrins, carbazoles, purines, and pterins. More preferred heterocyclic aromatic compounds include, for example, porphyrin , and phthalocyanine, and their metal complexes, for example copper phthalocyanine. Such a compound is available, from Eastman Kodak, Rochester, N.Y.
The organic material for whisker-like structures may be coated onto a substrate using well-known techniques in the art for applying a layer of an organic material onto a substrate including but not limited to vacuum evaporation, sputter coating, chemical vapor deposition, spray coating, Langmuir-Blodgett, or blade coating. Preferably, the organic layer is applied by physical vacuum vapor deposition (i.e., sublimation of the organic material under an applied vacuum). The preferred temperature of the substrate during deposition is dependent on the organic material selected. For perylene red, a substrate temperature near room temperature (i.e., about 25° C.) is satisfactory.
In the preferred method for generating organic whisker-like structures, the thickness of the organic layer deposited will determine the major dimension of the microstructures which form during an annealing step. Whisker-like structures 14 are grown on a substrate 11 with the characteristics and process described in U.S. patent application Ser. No. 07/271,930, now U.S. Pat. No. 5,035,961 , filed Nov. 14, 1988 and incorporated herein by reference. The process for obtaining whisker-like structures 14 is also described in Example 1 hereinbelow. Preferably, when the organic material is perylene red the thickness of the layer, prior to annealing is in the range from about 0.05 to about 0.25 micrometer, more preferably in the range of 0.05 to 0.15 micrometer. The organic materials are annealed and produce a whisker-like structure. Preferably, the whisker-like structures are monocrystalline or polycrystalline rather than amorphous. The properties, both chemical and physical, of the layer of whisker-like structures are anisotropic due to the crystalline nature and uniform orientation of the microstructures.
Typically, the orientation of the whisker-like structures is uniformly related to the substrate surface. The structures are preferably oriented normal to the substrate surface, that is, perpendicular to the substrate surface. Preferably, the major axes of the whisker-like structures are parallel to one another. The whisker-like structures are typically uniform in size and shape, and have uniform cross-sectional dimensions along their major axes. The preferred length of each structure is in the range of 0.1 to 2.5 micrometers, more preferably in the range of 0.5 to 1.5 micrometers. The diameter of each structure is preferably less than 0.1 micrometer.
Preferably, whisker-like structures 14, shown in FIG. 1, are substantially uniaxially oriented. Microstructures, 16, are a submicrometer in width and a few micrometers in length, and are composites comprising an organic pigment core whisker conformally coated with a conducting material.
The whisker-like structures preferably have a high aspect ratio, (i.e., a length to diameter ratio in the range from about 3:1 to about 100:1). The major dimension of each whisker-like structure is directly proportional to the thickness of the initially deposited organic layer. The areal number densities of the conformally coated microstructures 16 are preferably in the range of 40 to 50 per square micrometers.
The conformal coating material will generally strengthen the microstructures comprising the microstructured-layer. Preferably, the conformal coating material has electrically conductive properties and is selected from the group consisting of an organic material, such as electrical conducting organic materials, for example see "the Organic Solid State" Cowen et al., Chem & Eng. News, July 21 (1986) pgs 28-45, a metallic material, or a semiconductor inorganic material, such as silicon or gallium arsenide. More preferably, the conformal coating material is a metal or metal alloy. Preferably, the metallic conformal coating material is selected from the group consisting of aluminum, cobalt, nickel chromium, cobalt chromium, copper, platinum, silver, gold, iron, and nickel.
Preferably, the organic conformal coating material is selected from the group consisting of hetrocyclic polynuclear aromatics. The preferred inorganic conformal coating material is a semiconductor.
Preferably, the wall thickness of the conformal coating surrounding the whisker-like structure is in the from about 0.5 nanometers to about 30 nanometers.
The conformal coating may be deposited onto the microstructured-layer using conventional techniques, including, for example, those described in U.S. patent application Ser. No. 07/271,930, now U.S. Pat. No. 5,035,961, supra. Preferably, the conformal coating is deposited by a method that avoids the disturbance of the microstructured-layer by mechanical or mechanical-like forces. More preferably, the conformal coating is deposited by vacuum deposition methods, such as, vacuum sublimation, sputtering, vapor transport, and chemical vapor deposition.
Preferably, the encapsulating material is such that it can be applied to the exposed surface of the conformal-coated microstructured-layer in a liquid or liquid-like state, which can be solidified. The encapsulating material may be in a vapor or vapor-like state that can be applied to the exposed surface of the conformal-coated microstructured-layer. Alternatively, the encapsulating material is a solid or solid-like material, preferably powder or powder-like, which can be applied to the exposed surface of the conformal-coated microstructured-layer, transformed (e.g., by heating) to a liquid or liquid-like state (without adversely affecting the conformal-coated microstructured-layer composite), and then resolidified.
More preferably, the encapsulating material is an organic or inorganic material. The encapsulating material may exhibit sensitivity to gas or vapor contaminants to be detected. Additionally, it is preferable, although not required, that the encapsulant be permeable to gas or vapor contaminants.
Preferred organic encapsulating materials are molecular solids held together by van der Waals' forces, such as organic pigments, including perylene red, phthalocyanine and porphyrins and thermoplastic polymers and co-polymers and include, for example, polymers derived from olefins and other vinyl monomers, condensation polymers, such as polyesters, polyimides, polyamides, polyethers, polyurethanes, polyureas, and natural polymers and their derivatives such as, cellulose, cellulose nitrate, gelation, proteins, and rubber. Inorganic encapsulating materials that would be suitable, include for example, gels, sols, or semiconductor, or metal oxides applied by, for example, vacuum processes.
Preferably, the thickness of the coated encapsulating material is in the range from about 1 micrometer to about 100 micrometers, and more preferably in the range from about 6 micrometers to about 50 micrometers.
The encapsulating material may be applied to the conformal-coated microstructured-layer by means appropriate for the particular encapsulating material. For example, an encapsulating material in a liquid or liquid-like state may be applied to the exposed surface of the conformal-coated microstructured-layer by dip coating, vapor condensation, spray coating, roll coating, knife coating, or blade coating or any other coating method known to those skilled in the art. An encapsulating material may be applied in a vapor or vapor-like state by using conventional vapor deposition techniques including, for example, vacuum vapor deposition, chemical vapor deposition, or plasma vapor deposition.
An encapsulating material which is solid or solid-like may be applied to the exposed surface of the conformal-coated microstructured-layer liquified by applying a sufficient amount of energy, for example, by conduction or radiation heating to transform the solid or solid-like material to a liquid or liquid-like material, and then solidifying the liquid or liquid-like material.
The applied encapsulating material may be solidified by means appropriate to the particular material used. Such solidification means include, for example, curing or polymerizing techniques known in the art, including, for example, radiation, free radical, anionic, cationic, step growth process, or combinations thereof. Other solidification means include, for example, freezing and gelling.
After the polymer is cured, the resulting composite article 20 comprising a conformal-coated microstructured-layer and an encapsulating layer 12 is delaminated from the substrate 11 at the original substrate interface 15 (see FIG. 1) by mechanical means such as, for example, pulling the composite layer from the substrate, pulling the substrate from the composite layer, or both. In some instances, the composite layer may self-delaminate during solidification of the encapsulating material.
Capacitive properties of the composite article are determined by the dielectric constants of the encapsulating material, film thickness and planar area used. Intimate contact of the conductive particles with the surrounding encapsulant permits the full dielectric response of the encapsulant to be realized with only physical contact of a circuit lead to the conducting side of the composite, that is, without evaporation or sputter coating of a metal overlayer on the polymer surface as is usually necessary to bring a conductor into full electrical contact with a dielectric surface.
It is also a unique property of this medium's structural anisotropy that the complex impedance is anisotropic. That is, the impedance parallel to the surface of the composite film is predominantly resistive, while the impedance in the direction perpendicular to the surface is predominantly capacitive, being determined by the very large reactance of the much thicker encapsulant layer.
FIGS. 2 (a) and (b) illustrate a configuration utilizing the passive resistance (R) and capacitance (C) properties of thin flexible strips of the composite article of this invention. In all cases the resistance and capacitance character is spatially distributed over the entire area of the composite article. Referring to FIG. 2(a), a conductive metal foil tape is applied to the side of the encapsulating polymer opposite the conducting nanostructured side. Electrical contact can then be made at the three points x, y, and z. This is equivalent in a first order approximation to the three terminal network, as shown in FIG. 2(b). Depending on which pairs of terminals are used as input and output for an alternating current (AC) voltage signal, the composite strip can function as a low-pass or high-pass filter circuit. For example, applying the input signal across terminals x and z (or y and z) and taking the output across terminals y and z (or x and z) is equivalent to a low-pass filter. On the other hand, applying the input across terminals z and y (or z and x) and the output across terminals x and y (or y and x) produces a high-pass filter. Applying the output and input signals to the third combination of terminal pairs, for example, an input signal applied across terminals x and y (or y and x) and output measured across terminals z and y (or z and x), gives a simple capacitively coupled voltage divider. The metal foil tape need not be applied in a single piece and thus could produce multiple terminals. As used herein, "low-pass filter" means a filter network that passes all frequencies below a specified frequency with little or no loss. The term "high-pass filter" means a wave filter having a single transmission band extending from some critical frequency up to infinite frequency. The term "voltage divider" means a resistor or reactor connected across a voltage and tapped to make a fixed or variable fraction of the applied voltage available.
FIGS. 3 (a) and (b) illustrate a configuration that forms a four terminal network with two pieces of the nanostructured composite film arranged in "parallel" such that the conductive sides of the composite film are facing outward and the corresponding equivalent electric circuit. Electrical contact is made at the ends of each side, illustrated as points w, x, y, and z as shown. This can similarly be utilized to have different filter characteristics depending on the various combinations of terminals used for input and output, or to form various two and three terminal networks.
FIGS. 4 (a) and (b) illustrate a configuration to form a four terminal network with two pieces of the composite film arranged in "series" and a simplified equivalent electrical circuit. This arrangement is approximately equivalent to a band pass filter. Electrical contact is made at the ends of each side at points w, x, y, and z as shown. The term "band pass filter" means a wave filter with a single transmission band, wherein the filter attenuates frequencies on either side of this band. The metal foil tape 22 can be replaced with other composite strips.
Referring again to FIG. 1, as a sensor, it is found that the in-plane surface resistivity of the nanostructured side of the composite article 20, the impedance to current flow in the plane of the whisker-like structures 14, is a simple yet sensitive probe of gas, vapor, or liquid analyte effects. The electrical conductance mechanism may involve both electron "percolation" from point-to-point where adjacent whiskers touch, and tunneling through or charge injection into the thin intermediate encapsulating material 12 interstitially located between the conductive conformal coated microstructures 16. Therefore, if the conductivity of this conformal coating 13 applied to the whisker-like structures 14, or the relative separation of the microstructures 16, or the charge transport properties of the intermediate encapsulating material 12 are affected by the analyte, the surface impedance of the composite article 20 is altered. The initial surface resistivity is easily varied over a wide range by controlling the thickness of the conductive conformal coating 13 applied to the whisker-like structure 14 prior to encapsulation.
Sensor medium is produced in a convenient flexible polymer form which may be cut into arbitrary sizes and shapes. Electrical connections are simply made by contact with the conducting, chemically active surface.
Referring to FIG. 1, again the physical structure of the composite article 20, utilized as a gas, liquid or vapor sensor, comprises a polymer film 12, optionally, sensitive to the vapor or gas of interest, having encapsulated in its surface a dense, random array of discrete whisker-like structures 14. The whisker-like structures 14 are typically about one to a few micrometers in length and submicrometer in width. Microstructures 16 comprise organic pigment core whisker-like structures 14 with a conformal coating 13, typically a conducting material, and optionally, sensitive to the vapor or gas to be sensed.
The structure of the composite medium is illustrated in FIG. 1 and described hereinabove. Preferably, the encapsulating material 12 and the conformal coating may be selected for sensitivity to the gas/vapor/liquid analyte see Katritzky et al., "New Sensor-Coatings for the Detection of Atmospheric Contamination and Water," supra. Gases, vapors or liquids typically sensed include but are not limited to acetone, methyl ethyl ketone, toluene, isopropyl alcohol, hydrogen sulfide, ammonia, carbon dioxide, carbon monoxide, nitrous oxide, sulfur dioxide, organophosphorus compounds in general, dimethyl methylphosphonate, chloroethyl ethyl sulfide, xylene, benzene, 1,1,1-trichloroethane, styrene, hexane, ethyl acetate, perchloro-ethylene, cyclohexane, VMP naphtha, cellosolves, chloroform, methylene chloride, Freon™ 113, ethanol, ethylene oxide, hydrogen fluoride, chlorine, hydrogen chloride, hydrogen cyanide, toluene diisocyanate, methylene di-p-phenylene isocyanate, and formaldehyde. The preferred sensing property of the sensor is the electrical impedance.
The sensing composite article of the present invention is a dual mode sensor since the conductive conformal coating and the polymer encapsulant may each be selected for their individual response to a particular analyte molecule of interest.
The sensing composite article is a dual sensor in a second aspect, as well. Constructing a sensor as illustrated in FIG. 3(b), the effect of vapor/gas molecules absorbed by the encapsulant on its dielectric properties can be sensed by changes in the capacitance being measured. Since this impedance in the perpendicular direction is predominantly determined by capacitance, and is unaffected by the in-plane resistivity of the whisker surface layer, the perpendicular-capacitance and in-plane resistance values are independent.
Since the microstructure's conformal coating and the encapsulant may independently be chosen to have varying degrees of sensitivity to an arbitrary specific gas, vapor or liquid analyte, it is possible to combine a variety of such individually comprised sensors into a multiplexed array, whereby the integrated response of the array as a whole to an unknown gas, vapor or liquid composition, could be used to determine the composition of the unknown gas, vapor or liquid, the relative fractions of the components making up the later, or for a single analyte, the absolute concentration.
EXAMPLES
Objects and advantages of this invention are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention. Unless otherwise stated or apparent all materials used in the following examples are commercially available.
Examples 1 and 2 illustrate the basic procedure for preparing the composite articles of the present invention.
EXAMPLE 1
Organic pigment C.I. Pigment Red 149, (N,N'-di(3,5-xylyl)perylene-3,4:9,10-bis(dicarboximide)) [hereinafter referred to as perylene red], available from American Hoechst-Celenese, (Somerset, N.J.) was vacuum vapor deposited onto a stretched, 0.0125 mm thick sheet of copper coated polyimide, formed into a disc 8.3 cm in diameter. The resulting copper coated polyimide, having a 1000 Angstrom thick film of perylene red, was then annealed in vacuum, heating the entire continuous perylene red film coating the polyimide, by thermal conduction through the polyimide substrate. The perylene red film was heated at approximately 280° C. over a period of 90 minutes. After vacuum annealing, the disc had a nanostructured layer of discrete, oriented crystalline whiskers 1 to 2 μm in length. CoCr (86%/14%) was then sputter coated conformally onto the whiskers, using a conventional radio frequency (rf) glow discharge for 3 minutes at 13.7 MHz, with a 20 cm diameter target, 10 cm substrate-to-target distance, 24 mTorr of Argon (Ar), 500 watts of forward power and 1200 volts target bias.
Five milliliters (mL) of DUCO™ Cement "Household Cement" (Devcon Corporation), a solution of thermoplastic resin in toluene and other solvents, were applied to the center of the sample disc while spinning at 200 rpm. The disc was stopped when the cement flowed out to the perimeter of the sample disc. After air drying at room temperature for approximately 5 hours, the resulting nanostructured composite easily delaminated from the original polyimide substrate, producing a smooth surface where the now solidified cement had interfaced with the polyimide. The resulting dried thickness of the composite film was approximately 0.12 mm.
Two rectangular pieces of the composite were cut from different sections of the sample disc to give a sample with an area of 1.55 cm 2 . The end-to-end resistance of one strip was measured to be 12,060 ohms and the second strip measured 2910 ohms. The strips were pressed together between glass microscope slides with the electrically conducting nanostructured surfaces facing outward. The sinewave output from a signal generator over the frequency range of 1 kHz to 10 MHz was applied across the conductive surfaces on one end of the composite strip, that is the terminals x and w shown in FIG. 3(a). The output signal developed across contacts y and z shown in FIG. 3(a) were monitored with an oscilloscope having a 1 megohm, 20 picofarad (pF) input impedance using a 1× probe, or with a 10× probe having a 10 megohm, 13 pF impedance.
FIG. 5, curve (a) shows the measured output signal peak-to-peak amplitude normalized to that of the input signal. It is seen that the composite strips have an electronic transfer function similar to a low pass RC network, with a fall-off of approximately 6 dB/decade.
EXAMPLE 2
A second 8 cm diameter sample disc was prepared as described in Example 1, except CoCr was sputtered onto the perylene whiskers for 4 minutes at the conditions of Example 1, followed by encapsulation with 3 ml of DUCO™ cement. Two pairs of rectangular strips were cut from the sample and pressed together between glass microscope slides to form two composite strips. The same AC signal transfer function was measured as a function of frequency for each of these dual strips and are illustrated in FIG. 5. Referring to curve (b), the resistances of both sides of the dual composite strip (area of 2.7 cm 2 ) were approximately 4500 ohms. Referring to curve (c), the resistances were approximately 2200 ohms and area approximately 6.5 cm 2 . The dual composite strip thicknesses were approximately 0.05 mm. The frequency "cut-off" values shift in response to the capacitance and resistance of the strips.
EXAMPLES 3-10
The following examples illustrate a range of nanostructured composite sample types, varying with respect to the coating on the perylene whiskers and the polymer encapsulant used, to generate a series of equivalent RC network circuits with low-pass and high-pass cut-off frequencies that vary over several orders of magnitude. All samples were identically prepared up to and including the growth of the perylene whiskers. In each example, the sample type was identified according to the composition listed in Table 1. In each case, Scotch™ brand aluminum foil backed adhesive tape (3M Co., St. Paul) was applied to the polymer encapsulant side of each sample piece. Electrical contact was then made to the ends of the sample strip on the nanostructured side, and the metal foil tape on the opposing side, to form the three terminal networks shown in FIG. 2. The resistance across the conducting side of each sample was measured with a Keithley model 617 digital electrometer. The capacitance of each sample was measured as described below. A conventional 1.025 megohm resistor was placed in series with terminal x of a sample capacitor (FIG. 2), and a squarewave signal in the 100 Hz to several kHz range was applied to the 1.025 megohm resistor and terminal z (FIG. 2) across the two circuit elements. The voltage signal decay across the sample terminals y and z was monitored with an oscilloscope (10× probe) and the RC time constant read directly from the sample's capacitance waveform, allowing C (capacitance) to be calculated from Equation I
t=RC (I)
where R is the resistance in ohms, C is the capacitance in farads and t is the decay time in seconds for capacitance to discharge to 1/e of the initial charge.
TABLE 1______________________________________Sample ConformalType Coating Encapsulant______________________________________A Cu DUCO ™ Cement.sup.1B Cu Urethane/Vinyl.sup.2C Cu Fluorenone polyester.sup.2D Ag DUCO ™ CementE Ag Fluorenone polyesterF Au DUCO ™ CementG CoCr DUCO ™ CementH CoCr Fluorenone polyesterI Au Fluorenone polyester______________________________________ .sup.1 Devcon Corp., Danvers, MA .sup.2 3M Co., St. Paul, MN
Examples 3-5 illustrate the passive network response of small flexible strips of type D samples. A type D oriented nanostructure was made by first evaporating 750 Angstroms (Å) mass equivalent of Ag onto perylene whiskers in a conventional diffusion pumped bell jar vacuum system operating at approximately 10 -6 Torr pressure range, and then encapsulating the nanostructure as described in Example 1. The sample parameters are shown in Table 2. The low-pass frequency response curves are shown in FIG. 6 and identified in Table 2. The high-pass frequency response curves are shown in FIG. 7 and identified in Table 2.
Examples 6-8 illustrate the passive RC network response of small flexible strips of type H samples. The type H oriented nanostructure was made by sputtering CoCr (5 minutes under the conditions of Example 1) onto perylene whiskers and encapsulating the nanostructure in fluorenone polyester (FPE) by spin coating 7 ml of a 5% solution in cyclohexanone at a revolution rate sufficient to just cover the entire 8 cm diameter sample disc, followed by air drying for 16 hours at room temperature and 4.5 hours at approximately 70° C. The sample parameters are shown in Table 2. The low-pass frequency response curves are shown in FIG. 6 and identified in Table 2. The high-pass frequency response curves are shown in FIG. 7 and identified in Table 2.
Example 9 illustrates the passive RC network response of a small flexible strip of type G sample. The oriented nanostructure was made by sputtering 750 Angstroms mass equivalent of CoCr onto the perylene whiskers and encapsulating them in 5 ml of DUCO™ cement as in Example 2. The sample parameters are shown in Table 2. The low-pass frequency response curves are shown in FIG. 6 and identified in Table 2. The high-pass frequency response curves are shown in FIG. 7 and identified in Table 2.
Example 10 illustrates the passive RC network response of a small flexible strip of type A sample. The oriented nanostructure was prepared by sputtering Cu to a mass equivalent of approximately 600 Å onto the perylene whiskers and encapsulating in DUCO™ cement. The results are shown in Table 2. The low-pass frequency response curves are shown in FIG. 6 and identified in Table 2. The high-pass frequency response curves are shown in FIG. 7 and identified in Table 2.
The response curves in FIG. 7 appear to be band pass frequency response curves rather than high-response curves. This is due to oscilloscope input impedance, which in combination with the sample strips' half resistances, act as a low pass filter following the high pass circuit configuration shown in FIG. 2(b).
TABLE 2__________________________________________________________________________ExampleSample Area Thickness Resistance Capacitance Low-Pass Freq. High-Pass Freq.No. Type (cm.sup.2) (mm) (ohms) (pF) Response (FIG. 6) Response (FIG.__________________________________________________________________________ 7)3 D 12.1 .04 26 × 10.sup.6 146 a --4 D 1.54 .04 1.86 × 10.sup.6 61.5 b a5 D 3.52 .04 .20 × 10.sup.6 96 c b6 H 2.37 .025 .023 × 10.sup.6 63 d f7 H 13 .02 1180-1290 425 e d8 H 3.9 .02 560 171 h g9 G 2.5 .07 1760 40 f e10 A 2.1 .064 1005 51 g c__________________________________________________________________________
EXAMPLES 11-19
In Examples 11-19, the power dissipation capability of the nanostructured composite article, used in purely a resistive mode, is demonstrated and compared to a conventional carbon resistor and a thin metal film coated polymer.
In Examples 11-18, thin strips of varying surface resistance, formed with various metal/polymer combinations as described in Table 1, were heated by passing current through the strip until the test strip failed. The strips were laid against a glass slide with the nanostructured side against the glass and a temperature probe pressed against the opposite polymer side of the strip to monitor the temperature rise as a function of current level. The glass slide was not cooled. The plots of temperature rise versus electrical power dissipated in the composite strips was observed to be linear. Table 3 summarizes the results of eight sample strips, made from five sample types, as described in Table 1. Table 3 summarizes ΔT/ΔP, the slope of the linear temperature versus power plot, the test strip resistance, area, thickness, volume, and the maximum current density at the time of failure. The current density is calculated assuming the current carrying layer of the strip is approximately 2 μm thick, which is the known thickness of the nanostructured region of the composite article.
The last entry of Table 3 identified as example 19, shows similar measurements from a standard 12 ohms, 1/4 Watt carbon resistor, having cylindrical geometry. The current density of the carbon resistor is calculated using the inner carbon volume diameter. It is seen that the nanostructured composite films can support current densities 50 to 70 times larger than standard resistors of equivalent resistance and volume, for a similar temperature rise. This is due in large part to the larger surface area for heat dissipation. For Examples 11-19, it can be shown that the thermal conductivity of the polymer forming the bulk of the strip is the limiting thermal dissipation factor.
TABLE 3__________________________________________________________________________ExampleSample Area Thickness Volume Resistance ΔT/ΔP J.sub.MAXNo. Type (cm.sup.2) (mm) (cm.sup.3) (ohms) (°C./Watt) (amps/cm.sup.2)__________________________________________________________________________11 F 3.4 .064 .022 7.9 44.3 1412 (ΔT = 20° C.)12 D 3.0 .066 .020 12.7 29.0 1220 (ΔT = 16° C.)13 D 3.2 .066 .020 16 38.5 1061 (ΔT = 19° C.)14 B 3.6 .025 .009 33 23.0 375 (ΔT = 6.6° C.)15 C 1.2 .051 .0063 409 23.1 438 (ΔT = 25° C.)16 D 1.35 .038 .0051 1079 35.4 857 (ΔT = 15° C.)17 C 2.0 .028 .0056 5250 24.1 600 (ΔT = 7.9° C.)18 G 2.1 .097 .020 17730 27.3 225 (ΔT = 33° C.)19 Std. NA NA .030 12.2 40.2 19Resistor (ΔT = 20° C.)__________________________________________________________________________
EXAMPLES 20-23
In Examples 20-22, sample strips similar to those described in Examples 11-18 were resistively heated while heat-sinked to maximize the total power dissipation, and compared to Example 23, a cobalt film sputter-deposited on 0.05 mm thick polyimide. The sample strips were pressed tightly against a water cooled copper block with a thin film of heat transfer grease applied between the block and the polymer side of the nanostructured composite strips. Nextel™ (3M Co., St. Paul) insulating material was pressed against the nanostructured side of the strip, and a 0.025 mm diameter chromel-alumel (Type K) thermocouple measured the temperature at the midpoint of the conducting side of the strip through a small hole in the Nextel™ sheet. In this configuration, the surface temperature of the strip's conducting side was measured as a function of the input power, with thermal conductivity determined by the composite strip's polymer and its thickness, or in the case of the comparative Example 23, the polyimide substrate. The heat transfer grease, applied extremely thin, was observed to have a significant effect. The bulk thermal conductivity, k, across the thickness, d, of the polymer strip is simply related to the temperature drop across the strip, ΔT, the planar area of the strip, A, the electrical power dissipated in the strip, P, as shown in Equation II. ##EQU1## The thermal conductivity was found typically to be on the order of 2 mWatts/cm 2 ° C., indicative of a solid, polymer material.
For Example 20, composite article was formed by evaporating gold to a mass equivalent thickness of 1500 Angstroms onto an 8 cm diameter disc of perylene whisker coated polyimide, and encapsulating the latter with 6 ml of 4% solids FPE in cyclohexanone to form the nanostructured surface composite (type I) as described in Table 1. A test strip with an area of 4.0 cm 2 , thickness of 0.005 mm and an end-to-end resistance of 10.8 ohms was placed on the Cu block assembly described above. Curve (a) in FIG. 8 shows the measured temperature difference across the strip versus power until failure of the strip occurred.
For Example 21, a surface composite of type E (see Table 1) was formed by evaporating 1500 Angstroms of Ag onto the whiskers and encapsulating with 10 ml of 4% FPE. A strip with an area of 4.0 cm 2 , 0.05 mm thickness and 2.9 ohms resistance was mounted on the Cu block assembly. Curve (b) in FIG. 8 shows the measured temperature difference across the test strip versus the power dissipated in the strip.
For Example 22, a surface composite of type E was formed by evaporating 1950 Angstroms of Ag onto the whiskers and encapsulating with 10 ml of 4% FPE. A test strip with an area of 4.9 cm 2 , thickness 0.014 mm and resistance of 2.2 ohms was placed on the Cu block assembly. Curve (c) of FIG. 8 shows the measured temperature difference across the strip versus the power dissipated in the strip.
For comparative Example 23, approximately 1250 Angstroms of cobalt was sputter deposited onto a 0.05 mm thick polyimide web, using the conditions of Example 1. A strip was cut with an area of 4.4 cm 2 , and an end-to-end resistance of 2.8 ohms. Curve (d) in FIG. 8 shows the temperature difference across the polyimide strip versus the power input until failure, measured in same way as for Examples 20-22.
EXAMPLE 24
This example shows the use of the nanostructured composite film, with a metal coating and a polymer encapsulant, as a sensor capable of reversibly responding to a saturated vapor of acetone with a rapid response time and a sensitivity, according to Equation III
S=(R-R.sub.o)/R.sub.o =10% (III)
The organic pigment C.I. Pigment Red 149, (N,N'-di(3,5-xylyl) perylene-3,4:9,10 bis(dicarboximide), (available from American Hoechst-Celenese), was vacuum vapor deposited onto a stretched, 0.05 mm thick sheet of copper coated polyimide, formed into a disc with a diameter of 8.3 cm. The disc was vacuum annealed to form a nanostructured layer of discrete, oriented crystalline whiskers approximately 1.5 micrometers tall, as described in Example 1. CoCr (86%/14%) was then sputter coated conformally onto the whiskers, using a conventional rf glow discharge at 13.7 MHz for 8 minutes with 20 cm diameter targets, 10 cm substrate-to-target distance, 24 mTorr of Ar, 500 Watts forward power, 1200 volts target bias and water cooling of the target and substrate.
Three milliliters of uncured photopolymer, (cyclohexyl methacrylate, hexamethylene diisocyanate trimethylolpropane 5 (CHMA, HMDI-TA5)), as prepared in U.S. Pat. No. 4,785,064 was applied to the center of the polyimide disc and hand tilted to cause the solution to uniformly flow over and encapsulate the CoCr coated perylene whiskers. The photopolymer was then cured by exposing it to the appropriate UV lamps, under N 2 , for one-half hour.
The resulting nanostructured composite easily delaminated from the original polyimide substrate, (FIG. 1) producing a smooth, reflective surface where the now solidified polymer encapsulant had interfaced with the polyimide. An irregularly shaped piece of the brittle composite, approximately 5 cm long, 1.25 cm wide at the center and 0.5 cm wide at each end, was broken from the original disc. Electrical leads were attached to the ends by crimping on tinned solder lugs and coating them with conductive paint. The total resistance of the sample piece as described, was 843 ohms.
With leads from a Keithley model 616 electrometer attached to measure the resistance, and the latter driving a time based chart recorder, the sample was placed inside a covered 400 ml polyethylene beaker. With only air in the beaker, the resistance remained constant at 840 ohms for approximately 40 minutes. Acetone was then added to the covered beaker to a depth of 3 mm, so as to expose the sensor to a saturated vapor. The resistance (R) began to increase and rose to 855 ohms over a two minute interval. For approximately 15 minutes, the R remained at 855 ohms and then R increased sharply again to approximately 875 ohms over a period of 30 seconds and remained constant for 12 minutes. R then jumped to 900 ohms in a period of two minutes, thereafter remaining in the range of 900 to 880 ohms for 70 minutes. At this point, the sensor assembly was removed from the beaker and laid on the laboratory bench, whereupon R began dropping within seconds, reaching 790 ohms in 7 minutes and staying constant for 12 minutes until put back into the acetone vapor. R immediately began increasing again, reaching 900 ohms in 9 minutes where it remained constant.
In summary, this example of a nanostructured composite sensor with CoCr conformal coating and CHMA, HMDI-TA5 encapsulant has demonstrated the capability to rapidly and reversibly sense a room temperature saturated vapor of acetone with a sensitivity of approximately 10%.
The following example classes demonstrate the utility of the nanostructured composite film as gas/vapor sensors for H 2 S, Hg vapor, H 2 O and organic vapors of methyl ethyl ketone (MEK), acetone, toluene, isopropyl and ethyl alcohol, and as a liquid analyte sensor for aqueous Br. In all cases basic whisker structured perylene films deposited on copper coated polyimide sheets such as described in Example 24 were used as the starting point, and various combinations of metal conformal coatings and polymer encapsulants used to form thirteen different types of nanostructured composite films. Table 4 lists these different samples according to metal coating and polymer encapsulant as types A-M, which are referenced for brevity in the following Examples.
Photopolymer A was prepared as described in U.S. Pat. No. 4,510,593, Examples 6 and 2 and is incorporated herein by reference.
Photopolymer B is a radiation-curable composition prepared as described in U.S. Pat. No. 4,986,496, Example 4 and is incorporated herein by reference.
______________________________________Components Parts______________________________________urethane acrylate oligomer 68(XP51-85 ™, Cargile, Inc.)tetraethylene glycol diacrylate 19(SR-268 ™, Sartomer, Co.)diethoxyacetonphenone 5(DEAP ™, Upjohn Co.)fluorochemical surfactant 2.5(FC-431 ™, 3M Co.)n-vinyl pyrrolidone 5(GAF, Inc.)UV light stabilizer 0.5(TINUVIN 770 ™, Ciba Geigy, Inc.)______________________________________
TABLE 4______________________________________Sample ConformalType Coating Encapsulant______________________________________A Ag Photopolymer A.sup.1B Ag DUCO ™ Cement.sup.2C Ag Photopolymer B.sup.3D Ag Vinol polyvinyl alcoholE Cu Fluorenone polyester.sup.4F Au UV optical adhesive.sup.5G Au DUCO ™ CementH CoCr Photopolymer CHMA, HMDI-TA5.sup.6I CoCr Photopolymer AJ CoCr Fluorenone polyesterK Fe DUCO ™ CementL Cu DUCO ™ CementM CoCr DUCO ™ Cement______________________________________ .sup.1 U.S. Pat. No. 4,510,593 .sup.2 Devcon Corp., Danvers, MA .sup.3 U.S. Pat. No. 4,986,496 .sup.4 3M Co., St. Paul, MN .sup.5 Norland Products, Inc., New Brunswick, NJ .sup.6 U.S. Pat. No. 4,785,064 (cyclohexyl methacrylate, hexamethylene diisocyanate trimethylolpropane 5)
EXAMPLES 25-33
These examples demonstrate the utility of samples of types A, B, C, D, and E as irreversible sensors or dosimeters for H 2 S gas under conditions of high humidity, and illustrate the dependence of sensor sensitivity on the initial resistivity for quantitative analyses.
Example 25 illustrates that type B samples produce a significant response to H 2 S/N 2 concentrations as low as 30 ppm in times as short as 30 seconds under conditions of 50% relative humidity (R.H.) and 30 1/min flow rates.
A strip of type B sample, made by evaporating 900 Angstroms mass equivalent of Ag and encapsulating to a thickness of 0.045 mm, was cut 6 mm wide and 4.5 cm long. Electrical contact to the strip was made by simply clipping smooth-jawed miniature alligator clips to the ends of the strip. The initial resistance was 870 ohms. The strip was supported within a sealed 9 oz. glass jar and the resistance continuously monitored while gas mixtures of known composition and flow rate were admitted and allowed to vent through tubes penetrating the jar cover. Two sources of gases were mixed in a preliminary 9 oz. jar that supplied the final mixed gas to the sample containing jar. The first gas source was wet N 2 , produced by flowing N 2 over a humidistat (General Eastern) controlled water vapor bath through a glass flow meter tube (LabCrest No. 450-688).
The second gas source was either pure N 2 or 108 ppm H 2 S/N 2 (Union Carbide Industrial Gases Inc.) supplied to the mixing jar via a flow meter (Ace Glass Inc., tube #35). While flowing only humidified N 2 into the sample jar, the resistance remained constant at 869 ohms over a period of 35 minutes during which time the relative humidity was inceased from 50% to 78% in the first gas source, flowing at 16 1/min., and the second gas source of dry N 2 flowed at approximately 14 1/min., to produce a total flow of approximately 30 1/min. of humidified N 2 at approximately 25% to 39% RH. This demonstrates that a type B sensor is unaffected by water vapor, such as would exist in the vicinity of human breath. The valving of the second gas source was quickly switched to admit the 108 ppm H 2 S at approximately 5 1/min. in place of the dry N 2 , and immediately the resistance began rapidly dropping at a rate exceeding 100 ohms/min. as shown in FIG. 9 (a), finally approaching a stable and nonreversible resistance of 490 ohms, a decrease of 44%. This represents an average relative resistance change of 11%/min. over the first two minutes. The relative flow rates and mixture values imply that the rapid and large response of the strip's resistance was produced by approximately 30 ppm H 2 S/N 2 at approximately 40% RH.
For Example 26, a second strip of type B sample, 4.5 cm ×5 mm, having a lower resistivity than Example 25, was mounted in the same test apparatus as Example 25. The initial resistance of the strip was constant at 130.7 ohms while exposed to the wet N 2 gas mixture flowing into the mixing jar at approximately 23 1/min. and 55% RH. Upon switching to a mixture containing 35 ppm H 2 S gas, the resistance began dropping within seconds, reaching approximately 105 ohms in 2 minutes and eventually 82.2 ohms after 20 minutes. This represents an average relative change of resistance of approximately 10%/min. over the first two minutes, similar to Example 25, despite the difference in initial resistivity. It should be noted that the very stable resistance to nearly 1 part per thousand implies that even just a 25 ohms change from 130 ohms is still a signal to noise ratio of 20%/0.1% or 200/1.
For Example 27, a third strip of type B sample used in Examples 25 and 26 had an initial resistance of 3900 ohms. Unlike the previous examples, some sensitivity to water vapor was noted. The strip was mounted in the same test apparatus, but a simpler gas admission system was used in which either dry N 2 or the 108 ppm H 2 S//N 2 gas mixture could be admitted directly to the jar and vented through a second tube in the jar cover. Two ml of distilled water was added to the bottom of the test apparatus. The flow rates were not quantified, but produced a fast bubble out the 3 mm diameter (O.D.) vent tube when its outer end was placed in water. Upon switching from the pure N 2 to the H 2 S/N 2 gas, the sample resistance increased briefly to 4150 ohms over 30 seconds, then plummeted to 1000 ohms in 90 seconds, a sensitivity of 50%/min, and reached 260 ohms after 6 minutes. In comparison to the previous examples, this example indicates that the nanostructured composite sensitivity to H 2 S may be correlated to the initial resistivity.
For Example 28, a similar strip of type B sample, with 1000 Angstroms mass equivalent Ag, and a very low initial resistance of 15.4 ohms, was exposed to the same gas flow conditions as used in Examples 25 and 26. No response to the H 2 S gas was noted after switching from wet N 2 . This comparative example to Examples 25 to 27 indicates that too low an initial resistivity is not desirable. Sensitivity may be correlated to initial resistivity, probably because a different conduction mechanism may be dominating the current flow which is less sensitive to initial small degrees of reaction with the H 2 S.
For Example 29, a strip of type D sample, made by annealing the perylene whiskers at 240° C. for 80 minutes, vacuum evaporating 1000 Angstroms mass equivalent of Ag onto the whiskers, and solution coating with a 5% solution of vinol-polyvinyl alcohol in water with 0.1% Triton X-100, (Rohm & Haas, Philadelphia, Pa.) was cut 5 cm long and 6 mm wide. The strip's initial resistance under flowing dry N 2 in the simpler gas flow arrangement of Example 27 was 34 ohms. Switching to the 108 ppm H 2 S/N 2 gas source, in the absence of any water vapor in the apparatus produced no change in resistance. Three milliliters of water were added to the apparatus and the gas flow sequence repeated. With water vapor present, the resistance began dropping 90 seconds after switching to the H 2 S and exhibited a relative resistance drop of 10% over a period of approximately 11 minutes. This degree of change is also qualitatively consistent for such a low initial resistivity and the observations of the previous examples. It also indicates with this polymer encapsulant the need for finite relative humidity.
For Example 30, a strip of type C sample, made by annealing the perylene at 280° C. for 90 minutes, vacuum evaporating 1035 Angstroms mass equivalent of Ag and spin coating 3 ml of photopolymer B onto an 8 cm diameter disc and UV curing, was cut 3.7 cm long and 6 mm wide. The strip was exposed to N 2 and a 108 ppm H 2 S/N 2 gas mixture in the simpler gas flow arrangement of Example 27. Distilled water was present in the bottom of the apparatus. The initial resistance of the strip was 1.36K ohms and remained constant in a pure N 2 flow. Switching to the 108 ppm H 2 S/N 2 flow, the resistance began dropping after 1.0 minute, and decreased logarithmically as shown in FIG. 10.
For Example 31, a strip of type B sample with an initial resistance of 898 ohms was placed in the simpler gas flow arrangement of Example 27. Distilled water was present in the bottom of the apparatus. With only pure N 2 flowing into the apparatus, adequate to produce a fast bubble from the outlet tube, the resistance was constant. Upon switching to the 108 ppm H 2 S/N 2 flow, the resistance versus time curve broke at t=12 seconds after the start of the H 2 S flow, as shown in FIG. 9 (b), dropping at an initial rate of 36%/min, reaching less than 400 ohms within two minutes.
Example 32 shows that the resistance can also increase due to H 2 S exposure with a different metal coating on the whiskers and polymer encapsulant.
An example of type E was prepared by annealing the perylene whiskers for 160 minutes and sputter coating Cu for two minutes under the same rf and Ar pressure as cited in Example 24. It was then encapsulated in fluorenone polyester (FPE) by spin coating 5 ml of a 5% solution of FPE in cyclohexanone at a rate of 170 rpm onto an 8 cm diameter disc sample. After air drying, the FPE encapsulated nanostructured composite was cleanly delaminated from the original copper coated polyimide substrate. A piece with an initial resistance of 104 ohms was cut and mounted in the simpler gas flow arrangement described in Example 27. There was no water vapor present. Upon switching from pure N 2 to the 108 ppm H 2 S/N 2 flow the resistance began increasing very slowly as shown in FIG. 11. After several hours the resistance had increased to only 113.7 ohms, at which point the flow was stopped and the remnant vapors left in the sealed apparatus. As indicated in FIG. 11 the resistance began changing much more rapidly during the static conditions, until the pure N 2 flow was restarted.
In contrast to Examples 25 to 31, Example 33 illustrates that the resistance can increase upon H 2 S exposure even if Ag is used to coat the whiskers but a different encapsulant is used.
A type A sample was prepared by vapor coating a whiskered perylene sample with approximately 800 Angstroms of Ag, spin coating 5 ml of the ORP photopolymer at 450 rpm onto an 8 cm diameter sample disc, and UV curing. A piece with an initial resistance of 40.8 ohms was mounted in the simpler gas flow arrangement of Example 27. Distilled water was present in the bottom of the apparatus. With pure N 2 flowing, the resistance was constant to within 0.1 ohm. Upon switching to the 108 ppm/N 2 flow, the resistance began changing within 30 seconds, dipped briefly to 40.0 ohms over 2 minutes, and then began increasing monotonically, ultimately reaching 54.5 ohms after approximately 90 minutes. As in Example 32, it was observed that under static conditions, the rate of resistance change was faster than with positive flow. This effect is interpreted as due to nonequilibrium gas mixing in the simple single jar flow arrangement described in Example 27, and lowering of the relative humidity in the jar when the dry gas mixture is admitted.
In summary, Examples 25 to 33 show that the polymer encapsulant and metal coating both contribute to the response of the sensor to H 2 S, even causing the resistance to change in opposite directions for different combinations of metal and encapsulant, providing evidence that the conduction mechanisms and gas sensitivity involve both constituents of the nanostructure, unlike the prior art. These examples also show that a particularly useful combination for a fast, sensitive H 2 S sensor, which is not affected by humid air alone is Ag and DUCO™ cement.
Specifically for this combination and 108 ppm H 2 S/N 2 , Examples 27, 28 and 31 illustrate a logarithmic dependence of the initial rate of relative resistance change, 1/R o (dR o /dt), (or dS o /dt in %/min), on initial resistance, R o , as shown in FIG. 17. This result is potentially very important since it indicates a simple means to quantify the analyte concentration with these sensors. It is logical to assume that the slope of the straight line in FIG. 17 will vary with the relative concentration of H 2 S, and in fact this is supported by Examples 25 and 26 where effective concentrations of 30 and 35 ppm respectively produced initial sensitivity rates of approximately 10%/min for initial resistances of 870 and 131 ohms respectively. These data points are shown in FIG. 17 with dashed lines to indicate the hypothetical slope at those concentrations. (Note that all samples are type B samples). Given then two or more sensors, of different initial resistance, responding to the same gas concentration, it is only necessary to measure the initial rate of resistance change for each sensor, over one to two minutes, calculate the slope of a plot of the initial resistance rate of change versus resistance as indicated in FIG. 17, and compare to a calibration table to determine the analyte concentration. All of this could be done via integrated circuitry, and a multiplexed array of several of these sensors of regularly varying resistance could perhaps give good accuracy as well.
EXAMPLES 34 and 35
Examples 34 and 35 show that using gold as the conformal coating on the whiskers produces a mercury vapor sensor with a reaction mechanism dominated by solid state diffusion.
For Example 34, a type F sample was prepared by vapor coating 1500 Angstroms mass equivalent of gold onto a whisker coated substrate disc, spin coating with NOA 81 optical adhesive (Norland Products, Inc.) at approximately 250 rpm producing a UV cured film approximately 0.3 mm thick. The nanostructured composite was cleanly delaminated from the polyimide substrate. Strips of the composite, approximately 5 mm ×35 mm, were cut and individually mounted inside a test apparatus comprising a sealed 9 oz. glass jar having electrical leads penetrating the jar cover. The initial resistances were in the range of 120 to 600 ohms. The Hg vapor was generated by adding a few milliliters of pure Hg to the apparatus and placing the apparatus assembly into an air oven at controlled temperatures. After a resistance versus time run was complete at one temperature, a new sample strip was used to obtain another run at a new temperature, and hence vapor pressure. The Hg vapor pressure, hence the concentration was taken as the equilibrium vapor pressure of Hg at the given temperature. Four sample strips were exposed in this manner to Hg vapor between room temperature and 91° C. The sensitivity, defined by Equation III is plotted in FIG. 12 and demonstrates a strong temperature dependence and approximately a square root of time dependence, an indication that solid state diffusion is the rate limiting step.
Assuming a model for the gold coated whisker composite as a distribution of gold "posts" which are being converted to a AuHg alloy by solid state diffusion of Hg through the alloy to the alloy/Au interface, which is propagating down the length of the "post" as t 1/2 , the sensitivity can be expressed in terms of the resistivities of the Au and alloy, and a diffusion coefficient of Hg through the alloy. FIG. 18 shows a plot of sensitivity versus reciprocal temperature from which the temperature dependence of the diffusion coefficient can be extracted as shown.
For Example 35, a type G sample was prepared by vapor coating a mass equivalent of 2500 Angstroms of Au onto a whisker coated substrate, followed by encapsulation in DUCO™ cement by spin coating 4 ml of the adhesive at 440 rpm onto an 8 cm diameter polyimide disc and allowing it to air dry. As in Example 34, strips were cut from the delaminated composite and exposed to mercury vapor at various temperatures. The resistances of the strips were initially in the range of 5 to 20 ohms. For each new temperature, the sample was first monitored in a Hg free apparatus at the designated temperature, establishing that at any temperature the resistance was constant in air. When switched to the Hg containing apparatus, the resistance increased as shown by the sensitivity plot in FIG. 13, wherein a significantly larger response is recorded than with the type F sample in Example 34.
Examples 34 and 35 show that the sensitivity of the sensor for Hg, using Au as the reactive metal, is strongly dependent on the initial sample resistance, assuming the type of polymer is not as important in this case, and that a reaction mechanism can be extracted suggesting solid state diffusion and amalgamation. This implies that even more sensitive Hg vapor sensors could be created with different metal coatings, such as Al, although the Au may be beneficial where no reaction to water vapor or high temperature is desired.
EXAMPLE 36
Example 36 shows that using copper as the conformal coating on the whiskers produces an irreversible sensitive indicator of total water vapor exposure.
For Example 36, a type E sample was prepared as described in Example 32. Several strips were cut, 2-3 cm long and 6-8 mm wide, having initial resistances in the 50 to a few hundred ohms range. The strips, attached to the leads of an electrometer, were suspended directly over warmed water contained in an insulated Dewar. The resistance change versus time was then recorded for different average water temperatures, the latter generally remaining constant to within 1 degree during the exposure. FIG. 14 shows a summary plot of the sensitivity, S=(R-R o )/R o , versus time for seven strips at different water temperatures, and hence relative humidities. As indicated, the resistance change can vary over several orders of magnitude as the Cu coating on the whiskers is oxidized. There appear to be at least two regimes of behavior or kinetics, and the mid-range can be modelled assuming an Arrhenius relationship between S and exposure time, S=S o exp(mt). Using the slope at the inflection points of the log(S) vs. time curves to get m as a function of temperature, the latter is plotted vs. reciprocal temperature in FIG. 16, from which an apparent heat of enthalpy of only 11 kcal/mole results. This is considerably lower than reported heats of formation of most metal oxides, in the 30-200 kcal/mole range, with Cu approximately 60 kcal/mole. This high reactivity is probably a consequence of the high surface area of the whiskers and small size, which leads to faster response and greater sensitivity than solid thin film based sensors would exhibit.
EXAMPLE 37
Example 37 demonstrates the potential for selecting the polymer encapsulant to specifically sense organic solvent vapors. The gas concentrations were not varied or controlled in these experiments, rather the room temperature vapor pressures were used to simply demonstrate for different metal/polymer combinations that the response can be reversible and that the sensitivity is very dependent on the permeability of the gas or vapor into the encapsulant.
In Example 37, nanostructured film samples were made using four different combinations of metal coating and polymer encapsulant, in addition to that of Example 24. Strips similar to those described in previous Examples were cut from sample discs and electrical contact made to the ends by various means, including crimped indium foil and conductive silver paint. The resistance of each strip was then recorded against time, first with each strip suspended within a dry polyethylene beaker, in air, and then continuing after solvent was added to the bottom of the beaker.
Table 5 summarizes the observed average rate of resistance change for various solvents and indicates whether the response was reversible, when tested over one or two cycles. The total change, expressed as sensitivity S is also given where appropriate. The rate of sensitivity change increases with initial resistivity, since all pieces were about the same size and shape. Also, the affinity of the polymer for the solvent is presumably the primary reason for the large disparity of response of a single sensor type to various solvents.
TABLE 5______________________________________Sample Solvent R.sub.0 ΔR/ΔtType Vapor (ohms) (ohms/min) S (%) Reversible______________________________________E MEK 60 0.5 ˜ 25 yesE Acetone 1000 6 -- --E Acetone 8080 670 -- --E Toluene 105 ˜ 0 -- --E Toluene 900 1 -- yesE Isopropyl 86.5 0.025 -- -- AlcoholK Acetone 278 18 -- --K MEK 487 200-500 750 noK MEK 466 200-270 900 noJ Acetone 460 22 38 yesJ MEK 600 10 72 yesJ Toluene 1460 40 27 yesJ C.sub.2 F.sub.3 Cl.sub.2 1350 4 6 yesI Acetone 377 30 300 yes______________________________________
The resistance changes, which in all cases were increases, occur most probably due to both polymer swelling and the attendant increase in inter-whisker spacing, and changes in the intrinsic electronic transport properties of the interwhisker polymer material after sorbing solvent molecules. Similar resistance changes in three dimensional dispersions of carbon black particles in polymers is well known and often described in terms of percolation theory and the Hildebrand solubility parameter of the polymer and solvent. It is also conceivable that the polymer/metal interface of the coated whiskers is a controlling factor in charge injection or tunneling as well. The potential to tailor the polymer and metal combination for desired responses from specific gases or vapors would appear feasible. The results suggest, as with H 2 S, that the rate of sensitivity change may be correlatable with vapor concentration.
EXAMPLE 38
Example 38 demonstrates the use of the composite medium as a liquid analyte sensor.
A piece of type B sample, 6 mm ×40 mm, was held in the form of a semicircle by the electrical leads from an electrometer and immersed in a 180 ml volume of distilled water, contained in a 250 ml glass jar, so that the electrical clip leads were just above the water surface. The initial air resistance, 149.3 ohms, did not change when immersed in the water, until after several minutes, at which time the resistance began to slowly decrease at a constant rate of 0.26 ohms/min. over a period of 45 minutes. At this point, 1 milliliter of an equilibrium solution of Br 2 in distilled water was injected by syringe into the center of the 180 ml sample volume and briefly stirred, giving a 68 ppm aqueous Br solution. The resistance remained stable for approximately 2 minutes, then began rapidly decreasing at a rate of approximately 4 ohms/min., finally equilibrating after fifteen minutes for a total sensitivity change of 26%.
EXAMPLE 39
Example 39 demonstrates that the capacitance measured perpendicular to the film plane can be used as the sensor property.
Small area pieces, on the order of 2 cm 2 , were cut from B, E, L, and M type samples. Aluminum foil backed adhesive tape was applied to the polymer encapsulant side of each piece so as to form a simple capacitor with the nanostructured surface of the composite forming one conductive side of the capacitor and the aluminum foil the other. The thickness of the adhesive layer on the tape was much thinner than the composite film, the latter being in the 0.05 to 0.125 mm thickness range. Electrical contact to the formed capacitor was made by smooth jawed alligator clips. To measure the capacitance, a 1.025 megohm resistor was placed in series with the sample capacitor, a squarewave signal in the 100 Hz to several kHz range was applied across the two circuit elements, and the voltage signal across the sample capacitor was monitored with an oscilloscope. The RC time constant was read directly from the sample capacitor waveform, and the sample's capacitance calculated from Equation I. The sample test assembly was then placed in a covered beaker, directly over acetone liquid in the bottom, to expose the sample capacitor to a nominally saturated vapor. The RC time constant was then periodically read off the oscilloscope, the total circuit capacitance calculated and the scope probe capacitance subtracted to give the sample capacitance. FIG. 15 shows the variation of sample capacitance with elapsed time for the four sample types, beginning at t=0 when the samples were placed in the vapor.
By combining the capacitance property of the Example with the demonstrated surface resistance properties of Example 37, it is clear that the sensor media could be made into a resonant, tuned circuit element with a fast frequency shift type response.
Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein. | An electrically reactive composite article comprising a random or regular array of microstructures partially encapsulated within an encapsulating layer, microstructures each comprising a whisker-like structure, optionally having a conformal coating enveloping the whisker-like structure is described. The composite article is useful as an electrically conducting component of a circuit, antenna, microelectrode, reactive heater, and multimode sensor to detect the presence of vapors, gases, or liquid analystes. |
This application is a continuation of U.S. application Ser. No. 10/429,298, filed May 5, 2003, now U.S. Pat No. 6,863,702 which is a continuation of U.S. application Ser. No. 09/759,396, filed Jan. 12, 2001, now U.S. Pat. No. 6,558,453, which claims the benefit of U.S. Provisional Application No. 60/176,356, filed Jan. 14, 2000.
FIELD OF THE INVENTION
The present invention relates to vacuum cleaners, and more particularly, to a bagless dust cup assembly to be used in lieu of a disposable dirt collection bag with an upright vacuum cleaner apparatus.
BACKGROUND OF THE INVENTION
The present invention is directed toward an improved air/dirt separation system for an upright vacuum cleaner. The invention is further directed toward an assembly that may be retrofitted into an existing bag-style upright cleaner. The assembly according to the invention replaces a disposable bag system with an easy-empty permanent dustcup and cleanable permanent filter. Although the system successfully supplants the throwaway dustbag in this retro-fit application, the broader scope of the invention contemplates creation of an entirely new vacuum system that is dedicated to the bagless concept. Alternatively, by substitution of components, it is contemplated that the assembly of the present invention may be used to configure an upright vacuum cleaner that is adapted for either bag or bagless use.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a is a front elevational view of a vacuum cleaner according to the present invention;
FIG. 1 b is a cross sectional view of the cleaner as seen along line B—B of FIG. 1 a;
FIG. 2 a is a front elevational view of a dustcup of the cleaner;
FIG. 2 b is a rear and bottom perspective view of the dustcup;
FIG. 2 c is a top and front perspective view of the dustcup;
FIG. 3 a shows a top perspective view of the filter assembly of the present invention;
FIG. 3 b shows a side and bottom perspective view of the filter assembly and the cyclone module of the present invention;
FIG. 4 a is a top and side perspective view of a plenum chamber member;
FIG. 4 b is a top perspective view of the plenum chamber member;
FIG. 4 c is a top plan view of the plenum chamber member;
FIG. 4 d is a bottom plan view of the plenum chamber member;
FIG. 5 a is a top and side perspective view of a cyclone module;
FIG. 5 b is a side elevational view of the cyclone module;
FIG. 5 c is a top plan view of the cyclone module;
FIG. 5 d is a bottom view of the cyclone module;
FIG. 6 is an exploded perspective view of the assembly at the lower end of the handle;
FIG. 7 a is a rear perspective view of a rear handle bracket;
FIG. 7 b is a front perspective view of the rear handle bracket;
FIG. 8 a is a top and front perspective view of the front bracket;
FIG. 8 b is a bottom and rear perspective view of the front bracket;
FIG. 9 a is a top perspective view of a top-hinged support;
FIG. 9 b is a top perspective view of the top-hinged support;
FIG. 9 c is a top perspective view of the top-hinged support;
FIG. 10 is a front perspective view of a cover;
FIG. 11 is a view of the plenum chamber member and the top-hinged support connected together, with other portions of the assembly removed;
FIG. 12 a is a top perspective view of the motor intake adaptor;
FIG. 12 b is a bottom perspective view of the motor intake adaptor; and
FIG. 13 is a perspective view of the latch.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The dustcup assembly according to the present invention is used in all upright vacuum cleaner apparatus 100 having a vacuum cleaner base portion 101 , a vacuum cleaner body portion or rear housing 102 , and a vacuum cleaner upstanding handle 104 ( FIGS. 1 a – 1 b ). The base portion 101 includes a horizontally extending, elongated internal compartment 105 that receives a known rotating brush element (not shown) and cooperates with the body portion 102 to receive a known motor. The motor serves as a drive for the rotating brush and for a known suction fan or impeller. Rotation of the suction fan or impeller creates suction that is selectively communicated to a conventional hose (not shown), which may be operably connected to either the elongated internal compartment 105 containing the rotating brush element or to any of a number of known off-the-floor cleaning tools (not shown).
The body portion 102 is pivotally connected to the base portion 101 and has a rotational axis that is coaxial with the motor axis. The body portion 102 carries a filter/cyclone module, and has an upstanding handle 104 secured thereto.
A dustcup 106 ( FIGS. 2 a – 2 c ) is removably secured to the cleaner body portion 102 . The dustcup 106 is a molded plastic part that is preferably at least partially transparent, but may also be translucent or opaque. By having at least a part of the dustcup 106 transparent, the amount of collected dust can be readily seen by the operator and thereby visually indicates when the cup 106 should be emptied.
The dustcup 106 integrally provides and defines a dustcup chamber 108 and a dustcup passageway 110 . The dustcup chamber 108 is disposed toward a front side of the dustcup 106 and is open at a top section 107 of the dustcup 106 and closed at all other sections thereof. The dustcup chamber 108 receives and retains a dirt/dust mixture inducted into the vacuum cleaner apparatus 100 either by the rotating brush element or by any of the off-floor cleaning tools, and preferably, the dustcup chamber 108 has at least a transparent front wall 109 . Additionally, the dustcup chamber is provided with a step-like barrier 111 at the base thereof. Dirt-laden air flowing spirally downward impinges against the barrier 111 and dirt particles are caused to separate from the air by striking the barrier 111 . The filter/cyclone module is received by the top section 107 of the dustcup 106 and communicates with both the dustcup chamber 108 and the dustcup passageway 110 .
The dustcup passageway 110 is disposed toward a rear side of the dustcup 106 and defines a path for a stream of clean air to flow from an upper end of the dustcup 106 to a lower end of the dustcup 106 . The dustcup passageway 110 serves as a conduit that connects a lower motor inlet (not shown) to an upper plenum chamber 200 . In operation, the dustcup passageway 110 communicates suction from the motor/fan to the dustcup 106 , as will be apparent from the following description.
A dustcup handle 112 is attached to the front wall 109 of the dustcup 106 and provides a means for an operator of the vacuum cleaner apparatus 100 to easily grasp and hold or transport the dustcup 106 when it is independent of the body portion 102 .
The dustcup 106 has a generally round or circular top end region 113 that assists in receiving a cyclonic module. The inventors have found that the circular configuration of the dustcup top end region 113 is superior to other contours. However, it has also been found that the dustcup 106 may deviate from the round configuration as one moves downwardly away from the top end without negatively affecting the dirt-separating performance.
As will be described hereinafter, the cyclonic module receives a dirt-laden stream of air and separates the dirt from the air. The dirt is retained in the dustcup chamber 108 . The dirt-free air is directed to the motor/fan via the dustcup passageway 110 . The cyclonic module includes a filter assembly 114 ( FIGS. 3 a – 3 b ), a plenum chamber member 116 ( FIGS. 4 a – 4 d ), and a cyclone module 118 ( FIGS. 5 a – 5 c ).
The filter assembly 114 includes a filter 124 and a cup-like filter receptacle or holder 126 . The filter receptacle 126 removably fastens to and extends downwardly from the cyclone module 118 and has a generally frustoconical form.
The filter receptacle 126 is provided with a circular opening 127 defined by its large end 128 and is thus adapted to receive and support the filter 124 . The filter 124 is generally cone-shaped, with an open top end 129 , and is formed from an open cell flexible foam material. The filter 124 is slidably inserted into the circular opening 127 of the filter receptacle 126 . The filter receptacle 126 and associated filter 124 are adapted to be received by the cyclone module 118 . The filter receptacle 126 is provided at its large open end 128 with a plurality of mounting hooks 121 . The mounting hooks 121 extend upwardly from and are spaced circumferentially about the open end 128 . Each of the hooks 121 has a circumferentially directed projection 121 a that defines a slot-like void 122 between a bottom edge 121 b of the projection 121 a and the top edge of the open end 128 . Each of the mounting hooks 121 also has on its vertically oriented outside surface a rib-like projection 123 . The projection 123 , which is situated proximate to the slot-like void 122 defined by each of the hooks 121 , extends vertically across the outside surface of each of the mounting hooks 121 and works with the hooks 121 to removably attach the filter assembly 114 to the cyclone module 118 in a manner to be explained in subsequent discussion. In addition to the mounting hooks 121 the filter receptacle 126 is also provided at its large open end with a plurality of bump-like structures 125 . The bump-like structures 125 extend a relatively short distance upward from and are spaced circumferentially about the open end 128 and between the mounting hooks 121 . When the filter assembly 114 is attached to the cyclone module 118 , the bump-like structures 125 engage the cyclone module 118 in a manner that will also be subsequently described.
The filter receptacle 126 is further comprised of a plurality of elongated, rib-like appendages 191 that extend downwardly from the large open end 128 of the receptacle 126 . Each of the rib-like appendages 191 is angled inwardly relative to the open end 128 and connect at their lower end to an annular collar 192 that is integrally joined to the periphery of a flat, circular top portion 193 of a cylindrical lower portion 194 of the filter receptacle 126 . The cylindrical lower portion 194 is provided with a series of ribs 195 . The ribs 195 , which are molded into the outer surface of the cylindrical lower portion 194 , extend vertically along the outer surface and are separated from one another in the circumferential direction so as to define a series of depressions 196 between the ribs 195 . The ribs 195 and the depressions 196 cooperate to create a gripping surface that can be grasped by a user of the vacuum cleaner apparatus 100 and to impart rotational movement to the receptacle 126 for purposes to be subsequently described. surface and are separated from one another in the circumferential direction so as to define a series of depressions 196 between the ribs 195 . The ribs 195 and the depressions 196 cooperate to create a gripping surface that can be grasped by a user of the vacuum cleaner apparatus 100 and to impart rotational movement to the receptacle 126 for purposes to be subsequently described.
The filter receptacle 126 is further provided with a porous screen element 197 . The screen element 197 , which is preferably fabricated from interwoven nylon filaments, engages the periphery of the large open end 128 , the rib-like appendages 191 and the annular collar 192 so as to form a permeable barrier between the filter 124 and the air-dirt mixture that swirls about the interior of the dirtcup chamber 108 . The screen element 197 serves to prevent relatively large dirt particles from contacting and adhering to the filter 124 .
The cyclone module 118 ( FIGS. 5 a – 5 c ) is disposed beneath the plenum chamber member 116 and is secured to the plenum chamber member 116 via a plurality of upstanding screw-receiving bosses 140 . The plenum-chamber member 116 cooperates with the cyclone module 118 to define a peripheral labyrinth or tongue and groove sealing interlock 117 between a lower edge 119 of the plenum chamber member 116 and an upper surface edge 120 of the cyclone module 118 . This provides a means for positive positioning or registration between these elements of the assembly and air-tight sealing without the need for additional gaskets. The plenum chamber member 116 is further provided with a handle 115 that is removably fastened to the top of the plenum chamber member by known fastening means such as screws (not shown) that are received by the screw-receiving bosses 140 provided in the cyclone module 118 .
The cyclone module 118 includes an upper wall 142 that has a peripheral opening 141 that communicates with a peripheral volute passage 144 of a volute structure 145 , and a downwardly-flanged central opening 143 around which a plurality of relatively flat, elongated appendages 146 downwardly extend. The elongated appendages 146 angle inwardly relative to the central opening 143 and they are connected at their lower ends to a disk-like portion 139 . The appendages 146 and the disk-like portion 139 define a frustoconical, cage-like structure 150 . The cage-like structure 150 is dimensionally configured like the inside surface of the filter 124 and is thus made capable of receiving the filter 124 . The structure 150 acts both as a support for the filter 124 and as a means to prevent it from inwardly distorting or collapsing due to negative pressure when the vacuum cleaner apparatus 100 is in operation.
The wall 142 of the cyclone chamber 118 is provided with a first plurality of arcuate raised structures 153 . The structures 153 are arranged about the central opening 143 in a circular pattern and they define a first plurality of relatively deep inverted channels 154 that have openings 155 on the bottom surface 147 of the upper wall 142 and that further have openings 156 on the vertically extending sides 157 of the channels 154 .
Additionally, the upper wall 142 of the cyclone chamber 118 is provided with a second plurality of arcuate raised structures 158 . The structures 158 are arranged about the central opening 143 and located between the structures 153 so that the raised structures 158 lie on the same circle that passes through the raised structures 153 . The raised structures 158 define a second plurality of inverted channels 159 that are shallow relative to the inverted channels 154 and that have openings 160 on the bottom surface 147 of the cyclone module 118 . Also on the bottom surface 147 , a pair of rib-like projections 162 and 164 are provided. The projection 162 forms a circular arc and lies just radially outside of the inverted channels 154 and 159 . The projection 164 forms a continuous circle and is positioned radially between the central opening 143 and the inverted channels 154 and 159 . Both of the rib-like projections 162 and 164 extend a short distance vertically downward from the bottom surface 147 ; however, the rib-like projection 162 extends farther downwardly than the rib-like projection 164 .
The first plurality of inverted channels 154 and the second plurality of channels 159 are also situated on the wall 142 of the cyclone module 118 so that the bottom openings 155 receive the mounting hooks 121 of the filter receptacle 126 and so that the openings 160 receive the bump-like structures 125 also of the filter receptacle 126 . Once the mounting hooks 121 and the bump-like structures 125 are so received by the bottom openings 155 and 160 , they are caused to rotatably move within the channels 154 and 159 50 that, in the case of the mounting hooks 121 , the circumferentially directed projections 121 a and the rib like projections 123 are received by the side openings 156 of the channels 154 to secure the filter receptacle 126 to cyclone module 118 and so that, in the case of the bump-like structures 125 , the structures 125 cause the top 129 of the filter 124 , which projects a short distance vertically above the top of the filter receptacle 126 , to become compressed against the circular rib-like projection 164 and the portions of the bottom surface 147 of the cyclone module 118 , lying radially inward and outward of the projection 164 . The hooks 121 and the bump-like structures 125 are caused to rotatably move in the above described fashion when the user of the vacuum cleaner apparatus 100 grasps the downwardly extending portion of the filter receptacle 126 and twists the receptacle 126 in a clockwise direction relative to the bottom surface 147 of the wall 142 of the cyclone module 118 . When the receptacle 126 is so twisted, the bottom edge 121 b of the projection 121 a engages the top surface of the upper wall 142 and the rib-like projection 123 engages an outer edge of the opening 156 of the inverted channel 154 to resist rotational movement of the receptacle 126 until such time as the operator desires to remove the receptacle 126 and the filter 125 from the module 118 . It should also be noted that, when the projections 121 a and the ribs 123 engage the inverted channels 154 and the wall 142 in the above described manner, a portion of the outside surface of the top of the receptacle 126 rests just inside of the projection 164 an thus provides an outer seal for the filter 124 .
The inlet passageway or chimney 130 of the plenum chamber member 116 vertically aligns with the peripheral volute opening 141 of the cyclone module 118 and serves to introduce dirt-laden air tangentially into the top of the chamber 108 of the dustcup 106 via the cyclone module 118 . The volute structure 145 extends downwardly from the upper wall 142 and defines the passage 144 that extends spirally downward from the upper wall 142 .
Finally, a resilient gasket element 161 is mounted on the lower surface 143 of the flange that forms the perimeter of the cyclone module. The gasket 161 provides the seal between the cyclone module 118 and the top surface of the dustcup 106 .
When the plenum chamber member 116 and the cyclone module 118 are properly assembled an air space or chamber 200 is provided between the top wall 147 of the cyclone module 118 and the bottom surface of the plenum chamber member 116 . This air space 200 is required in order to allow airflow to communicate between the suction fan and the dustcup intake port.
To complete the adaptation of the dustcup assembly in this retro-fit application there is a need for components that will accept the dustcup 106 into the existing housing 102 with minimal impact to existing configuration and will enhance operator interface. Additionally, in order to maintain the minimum size of the shipping carton, the upstanding handle 104 is packaged detached from the vacuum body 102 . The upstanding handle 104 includes a peripheral handle rib 165 at the lower portion thereof. The handle rib 165 locates and retains the components that will ultimately interact with the dustcup 106 .
The lower handle assembly 170 ( FIG. 6 ) includes a rear handle bracket 171 ( FIGS. 7 a – 7 b ), a front handle bracket 172 ( FIGS. 8 a – 8 b ), a top-hinged support 174 ( FIGS. 9 a – 9 c ), and a top cover 176 ( FIG. 10 ). These components, in conjunction with a latch 178 ( FIG. 13 ) and various conventional springs and gaskets, define the assembly 170 that is permanently attached at the base of the upstanding handle 104 . When the upstanding handle 104 is mounted to the top of the rear housing 102 by the operator, the above listed parts of the assembly 170 work in concert with the dustcup 106 , as will be apparent from the following.
To complete the adaptation of the dustcup 106 to the existing upright rear housing 102 it is necessary to provide means for getting airflow from the suction fan into the dustcup passageway 110 that is located at the rear of the dustcup 106 . A motor intake adapter 180 ( FIGS. 12 a – 12 b ) provides a transition between the dustcup passageway 110 and the suction fan. The adaptor 180 is a molded plastic structure having a flat, generally rectangular base portion 181 , a walled structure 184 extending upwardly from the base portion 181 , a thin, vane-like structure 186 extending upwardly from the base portion 181 and outwardly from a side of the walled structure 184 , and a mounting flange 182 . The walled structure 184 defines a passageway 188 having a top opening 187 and a bottom opening 189 that is situated in the base portion 182 of the adaptor 180 . The passageway is preferably provided with an open cell foam filter 190 that serves as a final means to catch any dirt particles before the air stream enters the suction motor. The vane-like structure 186 is provided with a semi-circular aperture 185 . When installed in the vacuum cleaner apparatus 100 , the bottom side of the base portion 181 and the opening 189 of the passageway 188 are situated at the opening of the intake of the suction motor, the vane-like structure 186 engages an already existing post-like projection within the rear housing 102 , and the mounting flange 182 is captured by a preexisting rib structure inside the rear housing 102 and the motor cover. When the motor cover is attached to the rear housing 102 , the flange 182 of the adapter 180 is trapped between the suction motor intake and the preexisting rib structure of the housing 102 and a seal is created between the face of the motor intake and the motor intake adapter 180 . A molded gasket (not shown) is positioned on the top perimeter surface of a walled structure 184 and acts as the resilient seal that is compressed by the lower flange of the dustcup passageway 110 when the dustcup 106 is pivoted into its working position partially recessed inside the rear housing 102 .
In operation, with dustcup assembly installed, motor intake to suction fan is in fluid communication with a suction nozzle (not shown). Negative pressure is generated by the suction fan and pulls air through the system. Dirt mixed with air enters the nozzle, travels through the hose and continues through the hose connector. The hose connector is mounted to a chimney extension 175 on the tophinged support 174 . Air flows through the inlet 131 on the plenum chamber and into the top of the cyclone module intake port 143 and is caused to bend 90 degrees by the volute 145 and internal rib construction.
Air exits the cyclone inlet and enters the top of circular portion of the chamber 108 of the dustcup 106 in a path tangential to the inner wall. After traveling about halfway around the inside circumference of the dustcup chamber 108 , the air/dirt mixture encounters the helical downward-ramped spiral 149 of the base of the cyclone intake. As the air/dirt mixture encounters the spiral 149 , the mixture is encouraged to travel axially downward while still maintaining the centrifugal forces of high speed rotation that effectively separates the large particle matter from the air flow. Air passing the open end of the spiral acts as a siphon to help pull incoming air even more quickly into the interior of the dustcup chamber 108 . The greater that the velocity is of the air entering the dustcup chamber 108 , the greater is the efficiency of the system.
By introducing this ramped helical profile 149 to the interior contour, dirt is biased away from, the filter assembly 114 , providing less dwell time for the air/dust mixture to be in proximity to the filter assembly 114 . As the air/dust mixture is forced into a rapid circular motion, centrifugal forces act upon the more dense dust particles, pressing them against the inside walls of the dustcup chamber 108 and away from the filter assembly 114 . This reduces the effects of negative air-pressure that might otherwise cause dust to go directly into the filter 124 instead of precipitating to the base of the dustcup chamber 108 . The distinct advantage of locating the filter 124 in the top area of the dustcup chamber 108 is to keep it out of the accumulation of dust and debris that gather in the dustcup 106 and to maintain unimpeded air flow until the cup 106 is filled with dirt. There is less chance that dirt will collect around the filter element 124 and allows easier debris removal from the filter surface when servicing by the operator. After dirt and air enter the dustcup chamber 108 and are separated by centrifugal forces, because the air has less density than the dirt, it flows into the center area of the dustcup chamber 108 where it travels upward, attracted by the negative pressure area proximate to the filter 124 . The air travels past the screen element 197 and then through the open cell filter 124 and enters the plenum chamber 200 , while minute debris is blocked by the filter. The plenum chamber 200 is defined by the sealed space between the cyclone module 118 and the plenum chamber member 116 , and provides, a communication path for filtered air from the dustcup chamber 108 to the dustcup passageway 110 . Because the plenum chamber 200 is in fluid communication with the top of the clean passageway 110 of the dustcup 106 , filtered air proceeds to the motor intake and is ultimately routed into a HEPA filter element 199 before it is exhausted to atmosphere.
To empty the contents collected inside the dustcup 106 the operator must pull the spring-loaded latch 178 that is located on the front side of the top cover 176 . The latch 178 is provided with a latch projection 179 that disengages from a latch projection receptacle 173 provided in the front handle bracket 172 . Once the latch projection 179 clears the latch projection receptacle 173 , the top cover 176 and the top-hinged support 174 are free to pivot upwardly and are biased in this direction under influence of a coiled compression spring 183 nested between the the front handle bracket 172 and the top-hinged support 174 . When the top cover 176 and top-hinged support 174 pivot upwardly the outer flange skirt 177 of the top-hinged support 174 raises and allows the dustcup 106 to be removed without this intended interference. The operator grasps the handle 112 of the dustcup 106 and removes the dustcup 106 by pivoting it away from the rear housing 102 . There is slight pressure required to release the dustcup 106 from the housing 102 as the projection 138 on plenum chamber member 116 is designed to create a slight interference fit with the underside of the top wall in the rear housing 102 to prevent the dustcup 106 from unintentionally falling out of the unit. To empty the dustcup 106 the operator must grasp the handle 115 attached to the top of the plenum chamber member 116 and lift upward. The plenum chamber member 116 , cyclone module 118 and filter assembly 114 will come out from the inside of the dustcup 106 allowing easy emptying of contents. If cleaning of the filter 124 is also needed at this time the operator must turn the filter receptacle 126 by grasping the cylindrical lower portion 194 thereof and rotating the receptacle 126 through the minimal arc sufficient to disengage the mounting hooks 121 from the inverted channels 154 . This action causes the filter assembly 114 to be released from the cyclone module 118 . The filter assembly 114 can then be removed for final cleaning and servicing. After the filter assembly 114 is cleaned, it can be re-installed by reversing the foregoing directions for disassembly. The plenum/cyclone assembly can then be re-positioned inside the dustcup 106 and the cup 106 can then be reinstalled into the rear housing 102 .
Because the connector is mounted into the pivoting cover assembly, the hose connector disengages the intake chimney 175 of the top-hinged support 174 when opened and re-seals to the intake chimney 175 after the cover 176 is positioned in the closed position. when the cover 176 is in the fully closed (down) position the perimeter flange 177 resides on the outside of the upper flange of the dustcup 106 , thus holding the dustcup 106 in the proper operating postion without fear that the cup 106 will fall from the unit. As noted hereinbefore, the hose connector mates with the chimney extension 175 of the top cover to provide air continuity in the sealed system.
While the preferred embodiment of the invention has been describe above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modification which may fall within the spirit and scope of the invention. | A bagless vacuum cleaner system dustcup assembly and method for using said system with a vacuum cleaner apparatus to separate dirt from a mixture of dirt and air inducted into said vacuum cleaner apparatus. Said bagless vacuum cleaner system generally comprises a dustcup assembly, a handle assembly and a motor intake adaptor. |
TECHNICAL FIELD
In general, the present invention relates to a cutter used to section elongate materials. More particularly, the present invention relates to a cutter having a rotating blade.
BACKGROUND OF THE INVENTION
The present invention generally relates to a cutter used to cut elongate products into sections. For example, the cutter may be used to cut extruded profiles with or without reinforcement. These materials have proven difficult to cut with existing cutters.
One existing cutter uses a curved blade that cuts through the material in a scythe like manner. This type of blade may be used to cut material as it comes off an extruder in a continuous manner. Unfortunately, the curved blade cutter often distorts the material as it cuts making it difficult to maintain dimensional accuracy. This distortion also may result in a defective cut surface that is scalloped or otherwise irregular. These problems are pronounced when cutting softer materials.
Another existing cutter operates in a lathe-like manner with the material being mounted inside a rotating mandrel. Since the mandrel has a finite length, extruded material must be pre-cut and mounted before additional cuts are made. Consequently, such cutters are not suitable for continuous operation.
SUMMARY OF THE INVENTION
The present invention generally provides a cutter for cutting elongate material into sections, the cutter including a blade motor having a blade shaft, a blade mounted on the blade shaft, and an actuator adapted to move the blade along a drive axis into contact with the material to cut the material.
The present invention further provides a cutter for cutting elongate material into sections, the cutter including a motor coupled to a shaft, wherein the motor selectively rotates the shaft, a blade mounted on the shaft and rotatable therewith, a guard enclosing the blade, the guard defining an opening for receiving the material, a guard shutter mounted adjacent the opening and moveable to selectively cover the opening, and an actuator attached to the guard shutter and adapted to move the guard shutter between an open position and a closed position.
The present invention further provides a cutter for sectioning elongated material, the cutter including a shaft rotatably supported by bearings and coupled to a motor, wherein the motor rotates the shaft, an arm supported on the shaft and extending radially outward relative to the shaft, the arm being rotatably fixed to the shaft and rotatable therewith, a blade mounted on the arm and rotatable independently of the arm, and a blade motor coupled to the blade and adapted to rotate the blade.
The present invention further provides a cutter for cutting elongate material into sections, the cutter including a blade motor having a blade shaft; a blade mounted on the blade shaft, wherein the blade motor is adapted to selectively rotate the blade at a selected speed to cut the material; wherein the blade is supported by an actuator adapted to move the blade into contact with the material to cut the material; and a winding assembly including a spool located downstream of the blade, the spool being adapted to gather the material, and a controller adapted to activate the actuator as the spool becomes full, driving the blade to cut the material.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially sectioned side elevational view of a cutter according to the concepts of the present invention;
FIG. 2 is a top plan view of the cutter of FIG. 1 depicted with the guard shutter in an open position;
FIG. 2A is a top plan view of a cutter similar to the cutter shown in FIG. 2 with the guard shutter depicted in a closed position;
FIG. 3 is a front elevational view of a turret winding assembly having a cutter similar to the one depicted in FIG. 1 ;
FIG. 4 is a top plan view of a first alternative cutter according to the concepts of the present invention;
FIG. 5 is a front plan view of the cutter shown in FIG. 4 ;
FIG. 6 is side elevational view of a second alternative cutter according to the concepts of the present invention shown in a non-cutting position;
FIG. 7 is a side elevational view, similar to FIG. 6 , with the cutter depicted in a cutting position; and
FIG. 8 is a top plan view of the cutter depicted in FIG. 6 .
DETAILED DESCRIPTION OF THE INVENTION
The cutter according to the present invention generally includes a blade that is rotated on its axis by a motor. The blade speed may be controlled according to the type of material that is being cut. As shown, the blade may be circular and is constructed of a suitable material, such as, a metal or ceramic material. Other materials may be used depending on the particular application. In one example, a surgical steel blade was found suitable for cutting through both soft materials and harder materials, including those containing Kevlar™ fibers. Optionally, a lubricant, such as water, soap, or air, may be applied to the blade to facilitate cutting.
A guard may be provided to reduce the likelihood of injury. The guard may include a slotted opening exposing a portion of the blade. The opening may include walls that guide the material into contact with the blade. A guard shutter may be used to limit exposure to the blade by selectively closing the opening when the blade is not cutting material providing further protection against inadvertent cutting. The shutter may be any member that is moveable to block or otherwise limit access to the opening. The shutter's movement may be controlled manually by a switch or trigger, or controlled automatically by a system controller depending upon the application.
In the example shown in FIG. 1 , a cutter according to the concepts of the present invention is generally indicated by the numeral 10 . Cutter 10 includes a motor 20 , which may be an electric motor, as shown, or any other conventional motor that causes the blade 30 to rotate.
Motor 20 has a drive shaft 21 , which may be housed within a sleeve 22 . The drive shaft 21 may connect to a gear box 25 . In the example shown in FIG. 1 , a collar 23 extends from the gear box 25 and receives the shaft 21 . Drive shaft 21 may be slideably mounted within sleeve 22 and collar 23 to allow the cutter 10 to travel along the drive shaft axis D. It will be understood that gear box 25 is optional. The gear ratio created by gear box 25 may be used to improve motor torque. For example, a 2:1 reduction occurs in the depicted example. This particular gear ratio is not considered limiting, and it will be appreciated that other gear ratios may be used depending on the cutting application.
As shown in FIG. 1 , the gear box 25 may be used to allow the blade 30 to rotate on a different axis than the axis of the motor's drive shaft. This axis may be parallel to the drive shaft 21 or at angle as shown. In the depicted embodiment, the gear box 25 creates a 90° angle between the drive shaft axis D and the blade axis B. This particular angle, however, is not considered limiting, and the relative angle between blade axis B and drive axis D may vary depending on the location of the cutter 10 relative to other components and the material M to be cut.
Blade 30 attaches to a blade shaft 27 that extends outward from gear box 25 along the blade's axis B. The blade 30 may be attached to blade shaft 27 in any known manner. In the example shown, the blade 30 includes key 31 that fits within a keyway 29 formed on blade shaft 27 .
The blade 30 , so connected, is rotated by the motor 20 at a selected speed based on the type of material M that is being cut. In the example shown, the blade 30 is circular having generally circular cutting edge 33 at its radial outward extremity. Other blade shapes suitable for rotary cutting may be used.
As discussed more completely below, the cutter 10 may carry a sensor in monitoring its operation. For example, a sensor 35 may be mounted is sensing relation to the blade 30 to monitor its operation. As will be appreciated, the sensor 35 may be used to generate various information including blade speed, number of revolutions, or simply to determine whether the blade 30 is rotating. In the depicted example, sensor 35 is used to visually check for a broken blade. A second sensor may be used in conjunction with sensor 35 to reduce the likelihood that a broken blade 30 would go undetected. To that end, the second sensor may be circumferentially spaced from sensor 35 . In FIGS. 2 and 2A , openings 34 are provided in guard 40 to mount the sensors 35 and provide a line of sight to the blade 30 .
As best shown in FIG. 1 , guard 40 may include a plate 43 , which may be attached to gear box 25 , as by bolts. Plate 43 lies parallel to blade 30 on an inner side of blade 30 . Guard 40 may further include a sidewall 44 that extends axially outward relative to plate 43 to cover the edge 33 of blade 30 . To completely enclose blade 30 , guard 40 may include a cover 45 opposite plate 43 on the outer side of blade 30 . As shown, cover 45 may be removably attached against the guard 40 to cover the outer-side of blade 30 yet allow access to the blade 30 for repair and inspection purposes. As shown, the cover 45 may be made of a transparent or semi-transparent material, such as Lexan™ to allow visual inspection of blade 30 .
An opening, generally indicated by the numeral 46 , is formed in the guard 40 to expose a portion of the blade 30 . While only the edge 33 of blade 30 may be exposed as by an opening in sidewall 44 , opening 46 may extend radially inward to allow inward movement of material M relative to blade 30 , as shown in FIG. 2 . To that end, a slotted opening 46 may include slots 48 formed in plate 43 and cover 45 that extend radially inward from the radial outer extremity of a plate 43 and cover 45 . The slotted opening 46 may be configured for a particular application. For example, the walls of slots 48 may have a profile that generally conforms to the profile of the material M being cut. As shown, a rounded slot surface may be useful when receiving material having a circular cross-section. To that end, opening 46 may generally conform to the material M being cut to serve as a guide and hold the material while it is being cut.
For improved safety, a guard shutter 50 may be provided to selectively close the opening 46 . In the example shown, guard shutter 50 is rotatably mounted on guard 40 and may be rotated from a closed position ( FIG. 2A ), where the guard shutter 50 covers the opening 46 to an open position ( FIG. 2 ) away from the opening 46 . As shown, guard shutter 50 may have a somewhat C-shaped cross section ( FIG. 1 ) including a guard plate 53 located within guard 40 on the inner side of blade 30 , a guard sidewall 54 extending axially outward from guard plate 53 beyond the edge 33 of blade 30 , and a lip 55 extending radially inward from guard sidewall 54 outside of blade 30 . As shown, lip 55 may extend radially inward on the slot side to cover slots 48 formed in guard 40 to completely enclose edge 33 of blade 30 . To prevent lip 55 from interfering with sensors 35 , lip 55 may extend radially inward to a lesser extent to prevent the lip 55 from extending into the line of sight of sensor 35 . This would prevent the sensor 35 from falsely reporting that the blade 30 was intact due to the lip 55 extending into its line of sight. As an alternative to shortening the extension of lip 55 , openings may be provided in the lip 55 to ensure that it does not extend into the sensor's line of sight.
To accommodate sensors 35 that protrude inwardly from guard 40 , guard shutter 50 may define a slot 51 that extends circumferentially a distance suitable for providing the necessary range of motion for the guard shutter 50 to rotate between the open position ( FIG. 2 ) and the closed position ( FIG. 2A ). Also, the shutter 50 may define an opening 52 that corresponds to opening 46 , so that opening 46 opens when the opening 52 in the guard shutter 50 is aligned with opening 46 . Movement of the shutter 50 may be controlled by any known actuator or motor, which for simplicity will be generally referred to as an actuator and indicated by the numeral 60 . In the example shown, actuator 60 includes a pair of pneumatic cylinders 61 , 62 that attach to guard shutter 50 on opposite sides of guard shutter 50 . The cylinders 61 , 62 respectively push and pull shutter 50 to cause it to rotate in an alternating fashion to open and close the shutter 50 . Two cylinders 61 , 62 may be used to provide a measure of safety because guard shutter 50 will not open unless both cylinders 61 , 62 are in operation.
In accordance with the concepts of the present invention, cutter 10 may be used in connection with a winding assembly, generally indicated by the number 75 in FIG. 3 . Winding assembly generally includes a spool 77 that gathers material M in a continuous fashion until the spool 77 is full. At that point, cutter 10 may be driven toward a cutting position by an actuator 79 , such as a pneumatic or hydraulic cylinder, to make a cut. To make the cut, the blade 30 is rotated and advanced to contact the material M at a selected angle. The rotating blade 30 may be driven through the material M by actuator 79 . When using a guard 40 , the opening 46 of guard 40 is aligned with material M, so that the material M is received within opening 46 while making the cut. To further improve the safety of the winding and cutting system, a shutter 50 may be used to selectively expose the blade 30 within opening 46 . In this example, shutter 50 is opened as actuator 79 advances blade 30 toward material M allowing the material M to enter the opening 46 and be held by the walls of the slotted opening 48 as the blade 30 cuts through the material M. In the example shown, advancement of blade 30 is controlled by an air cylinder that drives gear box 25 and blade 30 along the drive shaft axis D. This actuator 79 also retracts blade 30 after the cut has been made allowing the material M to begin winding on a second spool. To facilitating cutting, a gripper 83 may be used to hold the material M as it is cut. Similarly, a traverse guide, generally indicated by the number 85 , may orient the material M relative to the spool 77 to provide successive coils and align the material M with the gripper 83 in preparation for a cut.
It will be appreciated that the cut of material M gathered on spool 77 may be timed or a controller C in communication with spool 77 and actuator 79 may be used to detect a selected amount of material on the spool 77 and activate actuator 79 to make a cut. It will be appreciated that the selected amount of material M on spool 77 might not always coincide with the capacity of the spool 77 . For sake of simplicity, however, this condition will generally be referred to as the spool being “full.”
In the example shown, two spools 77 are mounted on a turret. In this way, once the first spool 77 is full it is rotated by the turret counterclockwise away from the cutter 10 to a cut/unload position 77 A. At the same time, an empty spool rotated to a load position 77 B adjacent to the cutter 10 . In this position, the material M spans both spools 77 and the traverse guide 85 positions the material M in the path of the open gripper 83 B on the empty spool. Then, in preparation for the cut, gripper 83 B on empty spool grips material M just to the right of the cutter 10 . At the time of the cut, the spool 77 A stops winding and the gripper 83 A on the full spool closes. To make the cut, as actuator 79 drives blade 30 toward material M, the motor brings the blade 30 up to speed and the guard shutter is opened so that the material M is received within the slot formed in the guard as the blade 30 cuts through material M. Once the cut is made, actuator 79 retracts the blade 30 and the guard shutter is closed. Controller C monitors the cutter to ensure that it is in a fully cleared position before spool rotation begins.
Meanwhile, after the cut, the operator may open the gripper 83 A on the full spool 77 and removes full spool 77 A from the turret. Then, an empty spool is placed on the spindle at the cut/unload position 77 A. The process of turreting the spools 77 from the unload position 77 A to the load position 77 B continues making for a fully automatic winding and cutting system.
An alternate cutter according to the concepts of the present invention is shown in FIGS. 4 and 5 , and generally indicated by the numeral 110 . Cutter 110 , like cutter 10 , includes a rotating blade 130 , but differs in the method of bringing blade 130 into contact with material M. In this embodiment, blade 130 is mounted on a rotating arm 111 . Rotating arm 111 rotates in a plane that intersects the material M ( FIG. 4 ) and is used to periodically bring blade into contact with material M and make a cut. For cutting purposes, blade 130 may be caused to rotate independently of the arm 111 . In the example shown, arm 111 is mounted on a shaft 112 . The shaft 112 is rotatable and may be coupled to a motor 113 . A floating gear 114 is also mounted on shaft 112 and supported by dual bearings 118 such that it is freely rotatable on the shaft 112 . The floating gear 114 may be sized to accommodate two belts respectively connected to the blade 130 and motor 120 . As depicted in FIG. 4 , a belt 115 extends from the gear 114 to a gear 116 coupled to blade 130 . A second belt 117 extends from the floating gear 114 to a blade motor 120 to drive the blade 130 independently of shaft 112 . Notably, both the motor 113 and the blade motor 120 can be mounted to a stationary support 133 , and the floating gear 114 and the belts 115 , 117 permit the driving of blade 130 independently of shaft 112 .
As shown, the blade pulley 116 and blade 130 may be mounted on opposite sides of the arm 111 with a shaft 119 connecting the blade 130 to the pulley 115 . Blade shaft 119 may be supported in suitable bearings, as shown.
The blade 130 may be attached to blade shaft 119 in any known manner including the clamp assembly, generally indicated by the numeral 136 as shown. Clamp assembly 136 is keyed to blade shaft 119 such that it rotates therewith, and includes a chuck 136 A on which the blade 130 is mounted. A portion of the chuck 136 A extends through blade 130 and has a threaded end onto which a cap assembly 136 B is attached to clamp the blade 130 in place. So clamped, blade motor 120 via the belts and pulleys causes the blade 130 to rotate independently of the arm 111 .
As best shown in FIG. 5 , an arm motor 113 rotates the arm 111 to bring the rotating blade 130 into contact with the material M. The speed of the arm 111 may be varied depending on the type of material M to ensure an accurate cut. To improve efficiency, arm speed is generally the fastest speed that still produces an accurate cut. To increase the maximum arm speed, lubricants including but not limited to water, soapy water, alcohol, and cold air may be used.
The speed of arm 111 may also be varied along its rotational path. For example the speed after a cut is made may be increased to bring the blade 130 to the cutting position in a shorter period of time and then slowed to the cut speed at the time of making the cut. In this way, more cuts may be made than when operating the arm 111 at a constant rotational speed. Also, an increase or decrease in the non-cut speed can be used to compensate for the change in speed caused by blade 130 cutting through material M, referred to as “cut dwell.” The speeds and cut dwell may be measured in milliseconds (ms). For example, as schematically shown in FIG. 4 , as the blade 130 approaches a cutting position, the arm 111 may be slowed to the speed needed to cut the material M. Moving the arm 111 too fast could cause an inaccurate cut, mar the cut surface, or damage blade 130 . After the material M has been cut, for example when the blade 130 reaches a cleared position, the rotational speed of arm 111 may be increased to return the blade 130 to the cutting position. This phase of the arm's rotation is referred to as the “fast swing” in FIG. 5 . To maintain proper cuts, a controller C accounts for the changes in the arm's speed going from the non-cut phase to the cutting phase, referred to as the “cut swing” of the arm's cycle in FIG. 5 . The fast swing and cut swing phases may be defined by angular positions. In the example shown, the cut swing occupies an 80° segment located 140° from a home position located 180° opposite the center of the material M. After traveling through the cut swing, the arm rotated through the fast swing phase of approximately 280°. It will be appreciated that the cut swing and accordingly the fast swing will vary depending on the size of material M being cut. Therefore the angles shown for the cut swing and fast swing are not limiting. Also, any change in speed caused by blade 130 passing through material M may be accounted for by the controller C. With this information and the feed rate of the material M into cutter 110 , the controller C rotates the arm 111 to cut the material into desired lengths.
One example cut cycle is described in FIG. 5 . The example described is purely for illustration purposes and does not limit the invention. In this example, with the arm rotating at 200 rpm, one revolution equals 300 ms and the cut dwell is equivalent to 0.22 revolutions or 67 ms. The example follows with an explanation of the time and milliseconds for a given cut length, for example, 0.125 inches at a given cuts per minute speed. This speed is used to determine the feed rate and feet per minute.
The example further provides one cut cycle using the given example and discusses the coordination of the cutter 110 and the feeder (not shown). As described in the example, the part is selectively clamped and released as it is cut and then pulled away from the cutter 110 after the cut has been made. To that end, a guiding system may be provided for the exact placement of material. One guiding system includes a pair of arbors 148 split at the point of circular blade travel to support the product during the cutting process. The feeder may move material M at a speed and distance that is timed to provide the required cut length. As described, controller C may use a run/stop motion of the feeder and/or the arm 111 to achieve the desired cut length. As mentioned, the swing arm 111 can have varying speeds that may be independent of the cut window area. In this way, the cutter 110 can provide best cut quality at fast cut per minute rates for short parts, or for a long part, the arm 111 can be stopped until the required length is reached.
A counter weight CW may be attached to the arm 111 on the opposite side of blade 130 . The amount of weight and radial position may be adjusted to counterbalance the blade 130 .
The cutter 110 may be housed within a shroud to help protect the user and prevent foreign objects from interfering with the cutter's operation.
In another embodiment of the present invention, the cutter is incorporated in a hand-held device. For example, as shown in FIGS. 6-8 , the cutter 210 may include a rotating blade 230 driven by a motor 220 as described in the previous embodiments. As will be appreciated motor 220 may be any type of motor including, for example, an air motor, as shown. In this embodiment, the motor 220 is incorporated as the handle 275 for the device. In the example shown, an air motor is used and a nozzle 277 is provided on the end of the handle 275 to connect the motor 220 to an air supply (not shown).
The cutter 210 may be provided with a guard 240 that generally surrounds the blade except for an opening 246 exposing a portion of the blade 230 . As in the previous embodiment, guard 240 may include a cover 245 attached on one side of the guard 240 . The cover may have walls 246 a , 246 b that define an elongated slot-like opening 246 for receiving material M. In the example shown, the opening 246 is formed opposite the handle 275 .
As in the previous embodiment, guard shutter 250 may be provided to further protect the user from blade 230 and also to guide the material M into contact with blade 230 . In the example shown in FIGS. 6-8 , guard 240 defines a central recess 270 for receipt of a guard shutter 250 that defines a central slot 255 . Central slot 255 may be oriented generally perpendicular to the centerline of handle 275 . To prevent the user from contacting the blade 230 , shutter 250 may be actuated by an actuator 260 that can be activated to draw guard shutter 250 inward causing the material M located within the shutter's slot 255 to contact the blade 230 . As the first embodiment, actuator 260 may include a pair of air cylinders 261 , 262 to draw the material M toward a cutting position. In this position, the outer leg 256 of guard shutter 250 generally closes opening 246 formed by guard 240 . The inner leg 257 of guard shutter 250 also generally closes the opening 246 when guard shutter 250 is in an outwardly extended position ( FIG. 6 ) reducing the likelihood of the user accidentally touching blade 230 at any time. Operation of guard shutter 250 and blade motor 220 may be controlled by a trigger 280 mounted on handle 275 . For example, to cut material M, the user would locate the material M within the shutter's slot 255 and then depress the trigger 280 to start the blade's rotation and activate actuator 260 to draw the material M within the shutter 250 inward into contact with the blade 230 ( FIG. 6 ). Release of the trigger 280 could cause the actuator 260 to drive the shutter 250 outward releasing the material M. Alternatively, the actuator 260 may pull the guard shutter 250 inward against the force of a spring (not shown) such that release of the trigger 280 would deactivate the actuator 260 allowing the spring to force the guard shutter 250 outward.
It will be appreciated that other guard shutters may be used including one similar to the shutter 50 described in the first embodiment in connection with cutter 210 .
As can be seen from the above description, a novel cutter system has been shown and described. In accordance with the patent statutes, at least one embodiment of the present invention has been described. The embodiments discussed are for example purposes and do not limit the scope of the invention. For an appreciation of the scope of this invention, reference should be made to the appended claims. | A cutter for cutting elongate material into sections, the cutter including a motor coupled to a blade shaft, wherein said motor selectively rotates said blade shaft, a blade mounted on said blade shaft and rotatable therewith, and an actuator adapted to drive said blade along a drive axis toward the material. |
FIELD OF THE INVENTION
[0001] The field of the invention realtes to a tire sensor module.
BACKGROUND INFORMATION
[0002] Tire sensors are used in particular for measuring the tire pressure, i.e., as so-called tire pressure monitoring systems (TPMS). They are typically attached as sensor modules to the rim or the valve of the tire and transmit their data wirelessly with the aid of an antenna to a receiving unit of the vehicle, which relays the data to a central control unit of the vehicle.
[0003] The antenna is generally provided as a wire outside the sensor. During the mounting of the sensor module in the tire by being vulcanized in, for example, the antenna is therefore to be oriented in accordance with its design, which correspondingly results in complex mounting steps.
SUMMARY OF THE INVENTION
[0004] According to the exemplary embodiments and/or the exemplary methods of the present invention, the antenna of the tire sensor module is provided in or on the housing of the tire sensor module, i.e., it is not provided in the housing inner chamber or outside the housing, but rather is provided in the housing material, i.e., integrated, or is implemented on a housing side. In particular, it may be implemented on the housing interior side.
[0005] The antenna thus may not be deformed or changed in its orientation during vulcanization, as is possible with configurations outside the housing. Furthermore, the antenna also does not occupy any installation space in the housing interior chamber, in which the circuit carrier having at least the sensor element and possibly further components is attached. Therefore, a larger housing interior chamber is available as the sensor installation space at a given housing size. The antenna may nonetheless be designed with a substantial antenna length, in that it extends with the corresponding length in or on the housing.
[0006] According to a specific embodiment, at least the housing, but advantageously both the housing and also the circuit carrier, is designed to be rotationally symmetric. The antenna may run in a coil or helix in or on the housing and thus occupy a large antenna length. With a helix shape of this type, the antenna properties, in particular the emission characteristic, are essentially isotropic and/or uniform in the plane perpendicular to the coil axis.
[0007] The tire sensor module according to the present invention may thus be attached without orientation in the tire; it may be vulcanized into the rubber material, in particular in the area of the running surface, for example.
[0008] According to a first alternative specific embodiment, the antenna may be implemented on one housing side, which may be the housing interior side, as an antenna metal layer. A laser direct structuring method (LDS) is advantageously used for this purpose, at least one area of the housing being manufactured from a laser-activatable thermoplastic.
[0009] A manufacturing method of this type has the essential advantage that the geometry of the antenna may be adapted flexibly to the various applications. In the laser direct structuring method, a writing exposure method is used, so that only the data set, e.g., a CAD/CAM data set of the laser controller, is to be altered for different variants.
[0010] According to a second alternative specific embodiment thereto, the antenna may be laid as a metallic inlay part in the injection molding die and then extrusion coated by the housing plastic. This results in a simple and cost-effective manufacturing method.
[0011] The circuit carrier may be in contact with the antenna using a conductive adhesive bond between the circuit carrier and housing, the gluing allowing secure accommodation of the circuit carrier in the housing. Instead of the conductive adhesive bonds, pressure contacts, clamp connections, or press-in connections are also possible, so that no gluing is required during the final mounting of the circuit board in the housing. Furthermore, a contactless, in particular an inductive or capacitive connection of the antenna to the circuit carrier is also possible, so that no complex electrical contacting is required between the circuit carrier and the sensor housing. The mounting of the circuit carrier in the housing is thus significantly simplified.
[0012] The circuit carrier or the substrate may be a circuit board in particular, on which still further components, in particular an analysis and control ASIC and an RF ASIC may be attached in addition to the sensor element or sensor IC. Functions of this type may fundamentally also be partially or entirely integrated on the sensor IC, however.
[0013] Fundamentally, the tire sensor module according to the present invention may implement all measuring applications of tire sensors, in particular for measuring the (tire interior) pressure, temperature, or accelerations and/or vibrations. The various functions may also be combined if multiple sensor elements are used.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows a tire sensor module with an open housing in a perspective view.
[0015] FIG. 2 shows a perspective view of a housing part having an antenna according to a first embodiment.
[0016] FIG. 3 shows a cross section of the tire sensor module of the first embodiment having a coated antenna.
[0017] FIG. 4 shows a cross section of the tire sensor module of the second embodiment having an embedded antenna.
[0018] FIG. 5 shows a flow chart of the production method according to the present invention according to the two embodiments.
DETAILED DESCRIPTION
[0019] A tire sensor module 1 according to the present invention has a housing 2 having an upper housing part 2 a and a lower housing part 2 b, which are bonded to one another in a weld bond 3 and define a housing chamber 4 between them. Housing 2 is not designed to be hermetically sealed, at least for pressure measurements.
[0020] A circuit carrier 6 , e.g., a circuit board 6 or also a ceramic substrate, on which a sensor element 7 (sensor IC) and further components are attached, e.g., an analysis and control ASIC 8 for recording the measured values of sensor element 7 , possibly also for analyzing these measured signals, an RF ASIC 9 , and an oscillator 10 , is accommodated in housing chamber 4 . Circuit carrier 6 may be placed on a shoulder 11 of housing part 2 a , for example.
[0021] Sensor element 7 may be used for measuring different measured variables, in particular for measuring the tire pressure, as well as for measuring the internal temperature in the tire or accelerations and/or vibrations. Tire sensor module 1 may in particular also have multiple sensor elements 7 for measuring multiple status variables or measured values of this type.
[0022] An antenna 14 , 24 is implemented in or on housing 2 according to the present invention, i.e., not in housing inner chamber 4 or outside housing 2 , but rather in the housing material or on the interior or exterior side. According to the first embodiment of FIGS. 1 through 3 , antenna 14 is implemented as a metal layer on interior side 16 of housing 2 , e.g., of first housing part 2 a. For this purpose, housing 2 —or a housing part 2 a —is manufactured from a laser-activatable plastic, in particular a thermoplastic, e.g., from polymer types LCP, PA6/6T, or PBT. Plastics of this type are doped using metal-organic substances, which, after being exposed by the laser as activated seed crystals, make subsequent electroless metal plating possible. The metal-organic substance may be dissolved or extremely finely dispersed in the plastic; it may be a chelate complex compound of a noble metal, e.g., based on palladium or copper. Furthermore, a surface structure which is capable of high adhesion during the subsequent wet-chemical metal coating is produced at the plastic-metal interface during laser structuring.
[0023] According to the second specific embodiment of FIG. 4 , antenna 24 is embedded as a metallic insert part 24 in a housing part 2 a, for which purpose it is inserted in the injection molding die used during manufacturing.
[0024] Antenna 14 , 24 may be designed in both specific embodiments as a helix antenna or a screw-like antenna in particular, for which purpose housing 2 is advantageously cylindrical. A substantial antenna length may thus be implemented, the length accordingly resulting from the inner circumference of housing 2 and the number of turns or coils.
[0025] Antenna 14 , 24 is connected to circuit carrier 6 in an antenna connection 18 . According to one embodiment, electrical contacts are possible. An electrical contact of this type may be produced on the one hand in that a conductive adhesive is used at least in the area of the contacting of antenna 14 , 24 with circuit carrier 6 , i.e., circuit carrier 6 is fastened to shoulder 11 of housing 2 using an adhesive bond 12 , adhesive bond 12 or a partial area of adhesive bond 12 being electrically conductive and causing circuit carrier 6 (or a die pad or contact pad of circuit carrier 6 ) to be in contact with a contact pad 17 of housing 2 , at which antenna 14 or 24 is connected. An underfiller may additionally be applied below the circuit carrier to increase the mechanical stability.
[0026] Alternatively thereto, designs of antenna connection 18 as pressure contacts, clamp connections, or press-in connections are also possible, so that no adhesive bond 12 is required during the final mounting of circuit carrier 6 in housing 2 and the positioning and fastening of circuit carrier 6 and contacting of antenna 14 , 24 may be performed entirely via clamp and catch mechanisms.
[0027] Furthermore, antenna connection 18 may also be designed to be contactless, in particular inductive or capacitive, so that the complex electrical connection between circuit carrier 6 and antenna 14 , 24 is dispensed with.
[0028] Tire sensor module 1 may act in particular as a transponder, which receives query signals RF 1 via antenna 14 , 24 and produces transmission signals RF 2 from measurement signals of sensor element 7 , which are in turn transmitted via antenna 14 or 24 .
[0029] The manufacturing methods of the two specific embodiments are described in FIG. 5 . The production according to the first specific embodiment is performed in that (after the start in step S 0 ) housing 2 or a housing part 2 a is injection molded in step S 1 from a laser-activatable thermoplastic, and interior side 16 of housing 2 or housing part 2 a is subsequently exposed in step S 2 as the first processing step of the laser direct structuring method (LDS), after which a metal, e.g. copper, is deposited on the exposed points in step S 3 using wet chemistry. The copper may be reinforced and provided with a surface finish made of chemical nickel and immersion gold, for example. In step S 4 , circuit carrier 6 is inserted in housing 2 or housing part 2 a, antenna 14 also being in contact with circuit carrier 6 . In step S 5 , the housing is closed by welding housing parts 2 a, 2 b.
[0030] According to the second specific embodiment, antenna 24 is laid as a metallic insert part in a casting mold or injection molding die in step S 7 , subsequently embedded in housing part 2 a in step S 8 , and circuit carrier 6 is then inserted in housing 2 or housing part 2 a so that antenna 14 is in contact with circuit carrier 6 according to step S 4 .
[0031] Thus manufactured tire sensor module 1 may in particular be vulcanized into the rubber material of a tire 30 in a subsequent step S 6 . Because tire sensor module 1 is designed to be rotationally symmetric in the specific embodiment shown and its antenna 14 is implemented as at least essentially rotationally symmetric, namely it has an essentially uniform emission characteristic in the plane perpendicular to the coil axis because of the helical shape or coil shape, it is also possible to attach tire sensor module 1 in the tire without orientation in specific planes. Tire sensor module 1 according to the present invention may thus also be vulcanized into the running surface, e.g., in the area of the steel belt. | A tire sensor module having a circuit carrier, on or in which at least one sensor element is attached for measuring a measured variable, an antenna for transmitting sensor signals to a receiving unit of the vehicle, and a housing, in whose housing inner chamber the circuit carrier is received, the antenna being provided in the housing material of the housing or on a housing side of the housing. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a radio telephone system and a method for controlling the radio telephone system comprising a radio telephone set utilizing a rechargeable battery as its electric source, and a base unit connected to the radio telephone set through a radio channel and through which speech signals are transmitted between the radio telephone set and a wired telephone line, and more particularly, a radio telephone system and its controlling method capable of prohibiting a continuous transmission state caused by the failure in the operation of a speech channel termination switch while the battery of the radio telephone set is being charged.
2. Description of the Prior Art
As is well known in the art, a prior art radio telephone system is constituted by a base unit connected to a wired telephone line, and a radio telephone set controlled by the base unit for exchanging speech signals between the radio telephone set and the wired telephone line. When an origination switch in the radio telephone set is operated, a control circuit controls a transmitter and a receiver to establish a radio speech channel between the radio telephone set and the base unit, thus permitting speech. When the speech is terminated, a termination switch is closed for terminating the speech channel.
In an ordinary telephone set, the origination and the termination of the speech channel are effected by on-hook and off-hook operations of a handset of the telephone set, but in some type of the radio telephone systems, the origination and the termination of the speech channel are controlled by independent switches.
In such a system, if the speech channel termination switch fails to be operated when the speech has terminated, the speech channel between the base unit and the radio telephone set, and further between the base unit and the wired telephone line will remain in the speech state, thus prohibiting the channel from being used for other speeches.
Especially, in a system constructed such that the radio telephone set is mounted on and connected to the base unit when not in use so as to charge the battery in the radio telephone set and it is dismounted when in use, since electricity in the electric source is not consumed during the charging, the speech state will be maintained until the troubles is noticed and the speech channel termination switch is operated.
For this reason, a display device or a warning device has been used for informing the fact that the speech state is maintained or a timer is provided for automatically terminating the speech channel when the speech state is maintained beyond a predetermined period.
In the system in which whether the telephone system is in the speech state or not is informed by a display device, the display is likely to be mistaken as a display of other display devices so that there is a defect that the speech channel termination switch cannot be operated correctly.
Where the speech channel is forcibly terminated, there will be a case in which the speech channel is unfavorably terminated during actual talking.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide an improved radio telephone system and method for controlling the radio telephone system to prevent a speech channel from being in continuous use state without interfering an actual speech even when a user of the telephone set forgets to perform a speech channel termination operation.
According to this invention, there is provided a radio telephone system comprising a radio telephone set utilizing a chargeable battery as an electric source, a base unit connected to the radio telephone set through a radio channel for exchanging a speech signal between the radio telephone set and a wired telephone line, means for detecting a charged state of the battery and means responsive to the output signal of the detecting means for terminating the radio channel between the radio telephone set and the base unit.
More particularly, by utilizing the fact that after completion of a speech, the radio telephone set is connected to the base unit so as to charge the battery in the radio telephone set, according to this invention, after termination of a speech, the initiation of charging of the battery is detected and the radio channel is terminated in accordance with the detection.
Consequently, according to this invention, initiation of the charging of the battery when a speech is terminated is detected and the detection is used as a speech termination procedure so that continuous use of a speech channel can be prevented even when the user forgets the speech channel termination procedure. Since the speech channel is terminated after termination of an actual speech, no trouble is caused in the actual speech and the speech channel is available for other speeches.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a block diagram showing one embodiment of this invention;
FIG. 2 is a connection diagram showing one example of a detection circuit;
FIG. 3 is a block diagram showing a modified embodiment of this invention; and
FIGS. 4 and 5 are flow charts showing the operation of the embodiments of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In a preferred embodiment of this invention shown in FIG. 1, a speech signal from a wired telephone line 1 is transmitted to a receiving antenna 12 of a radio telephone set 3 via a hybrid circuit 9, a transmitter 10 and a transmitting antenna 11. The received signal is transmitted to a speaker 13 via a receiver 5. A speech signal inputted into a microphone 14 of the radio telephone set 3 is transmitted through a transmitter 6, a transmission antenna 15, a receiving antenna 16, a receiver 17 and the hybrid circuit 9 to the wired telephone line 1.
In a base unit 2, an AC/DC converter 18 energized by a 100 volt alternative current source is utilized and its output is used to charge a battery 20 of the radio telephone set 3 through contacts 19A and 19B. The radio telephone set 3 can be used separately from the base unit 2 by disconnecting the contacts 19A and 19B.
After completion of the speech, if a user fails to operate a speech channel termination switch 7 and connects the radio telephone set 3 to the base unit 2, a detection circuit 21 detects that the battery charging starts. Then, in response thereto, a control circuit 22 disconnects the transmitter 10 from the power source (AC/DC converter 18), thus disabling the transmitter 10. When the receiver 5 detects an interruption in a radio wave from the transmitter, a controller 23 disables transmitter 6 in the radio telephone sets to bring it to a waiting state, thus preventing unfavorable continuous transmission. In this case, a circuit for detecting the radio wave interruption can be constituted by a known noise squelch or carrier squelch circuit.
An origination switch 4 and the speech termination switch 7 may be combined into a single switch which is used for origination by turning it on and for speech termination by turning it off. The charging contacts 19A and 19B may be constituted by metal pieces or plug and jacks.
FIG. 2 shows one example of the detection circuit 21, in which the output terminal of the AC/DC converter 18 is connected to a terminal 24 which is connected to contact 19A through a resistor 25 for determining the charging current, and to an inverting input of a comparator 28. The voltage at the terminal 24 is divided by resistors 26 and 27 and the divided voltage is applied to a non-inverting input of the comparator 28.
Suppose now that the input voltage to the terminal 24 is 10 V, the voltage after charging (maximum voltage) of battery 20 is 7 V, the resistors 26 and 27 have resistance value of 100 kΩ and 1MΩ, respectively. Then at the time of not charging, a voltage
10 V×{1MΩ÷(100kΩ+1MΩ)}=9 V
is applied to the non-inverting terminal of the comparator 28, whereas 10 V is applied to the inverting terminal so that the voltage at an output terminal 29 of the comparator 28 is at a low level (about 0 V). On the other hand, at the time of charging, since a voltage of less than 7 V is applied to the inverting terminal, the voltage at the output terminal 29 becomes a high level (=the driving voltage V cc of comparator 28). Consequently, the output voltage of comparator 28 becomes a high level. Thus, whether the battery is being charged or not can be detected from the output of the comparator 28.
The detecting circuit 21, can be substituted by a CMOS inverter or the like. Further the detecting circuit 21 may be installed in the radio telephone set 3 so as to stop the transmission of the electric wave from the radio telephone set 3.
Instead of installing the AC/DC converter 18 in the base unit 2, an AC/DC converter 30 can be installed on the outside of the base unit 2 as shown in FIG. 3 so as to detect the charging state on the side of the radio telephone set 3.
FIG. 4 shows the operation of the above-described embodiment.
In the flow chart shown in FIG. 4, at steps 31 and 32, a judgment is made as to whether the charging has been made for a predetermined period or not. The purpose of step 31 is to assure the speech channel by disconnecting the radio telephone set from the charging source at once when it is inadvertently connected to the charging source. On the other hand, the purpose of step 32 is to assure the speech channel when the electric wave is temporarily interrupted due to fading etc.
FIG. 5 is a flow chart showing the operation of another embodiment. In the flow chart of this embodiment, a step 33 for detecting whether or not the battery is currently being charged is added to the steps in the FIG. 4. In this embodiment, the speech channel is established while the battery is being charged.
Instead of providing a detector for detecting whether the battery is being charged or not in the base unit or a radio telephone set, it is possible to provide the detector for both the base unit and the radio telephone set. With this construction, both the base unit and the radio telephone set are turned off in response to the output of the detector. | In a radio telephone system comprising a radio telephone set utilizing a rechargeable battery, and a base unit connected to the radio telepone set through a radio channel for exchanging a speech signal between the radio telephone set and a wired telephone line, there are provided a detector for detecting the charged state of the battery, a terminating device responsive to the output signal of the detector for terminating the radio channel between the radio telephone set and the base unit. |
[0001] This application claims priority to US provisional application having Ser. No. 61/933422, which was filed Jan. 30, 2014, and is incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The field of the invention is biological fixation of carbon dioxide, particularly using genetically modified microorganisms.
BACK 2 ROUND OF THE INVENTION
[0003] The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0004] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0005] Carbon fixation is commonly performed by autotrophic plants and microorganisms such as chemoautotrophic and phototrophic microorganisms by incorporation of CO 2 into more complex molecules, typically via the CBB cycle (Calvin-Benson-Bassham cycle, also known as reductive pentose phosphate cycle). In this cycle, three molecules of CO 2 are fed through a series of enzymatic reactions that generate a variety of phosphorylated compounds, which when coupled to glycolysis, produce a single molecule of acetyl-CoA.
[0006] Due in part to this ability to fix atmospheric carbon, a number of methods have been developed to divert the products of these reactions into commercially valuable materials such as alcohols, fuels, and biodegradable plastics. For example, WO 2009/098089 to Duhring et al. teaches certain genetic modifications of photosynthetic autotrophs to enhance activity or to modify cofactor specificity of enzymes involved in the production of specific metabolites, and to overexpress enzymes involved in ethanol synthesis from such metabolites. Similarly, US 2012/0142066 to Baier et al. teaches genetically engineered photoautotrophs to enhance ethanol production by overexpression of enzymes involved in the ethanol synthesis and reduction of activity of enzymes that utilize intermediates in the ethanol synthesis in alternate pathways. While at least somewhat effective, such methods are typically limited to ethanol production and, in addition, fail to address issues of inefficient fixation of CO 2 .
[0007] More recently, an improved CO 2 fixation process was reported where a non-oxidative glycolysis (NOG) step used three molecules of fructose-6-phosphate to produce three molecules of acetyl-CoA, and where further carbon rearrangement reactions were needed to regenerate two molecules of fructose-6-phosphate (see e.g., Nature 502, 693-697 (31 Oct. 2013)). Thus, one molecule of ‘surplus’ fructose-6-phosphate from the CBB cycle was used to form three molecules of acetyl-CoA, and six molecules of CO 2 were needed to obtain via glyceraldehyde-3-phosphate the fructose-6-phosphate. Therefore, viewed from a different perspective, the NOG pathway required a transaldolase key step (C6+C4→C3+C7) and subsequent conversion of glyceraldehyde-3-phosphate to fructose-6-phosphate before the fructose-6-phosphate enters the non-oxidative glycolysis. However, while at least somewhat improving CO 2 fixation, additional genetic modifications were required to absorb and reconfigure the erythrose-4-phosphate byproduct from the acetyl-CoA generation and to ultimately regenerate fructose-6-phosphate.
[0008] Regardless of the efficiency of CO 2 fixation, at least some of the microorganisms that produce value products (e.g., alcohols, polyhydroxyalkanoates, etc.) often require substantial quantities of nitrogen (typically in form of ammonia) to grow to a desirable cell density. Unfortunately, relatively high nitrogen levels favor cell growth over value production, and the cells are typically shifted to nitrogen-limiting or nitrogen depletion conditions to shift the cells to value product formation. However, low nitrogen levels in the growth medium have also been found to reduce the rate of CO 2 fixation, likely by feedback inhibition of a CBB cycle metabolite, limiting overall yield of the value products.
[0009] Thus, there is still a need for methods and compositions that permit efficient carbon fixation by autotrophic organisms under conditions that also permit efficient production of value added materials without imposing undue metabolic burden and additional catalytic activities onto a cell. Moreover, there is also a need to provide metabolically engineered cells that can produce value products at a high rate under nitrogen-limiting or nitrogen depletion conditions without feedback inhibition by a CBB cycle metabolite that accumulates under such conditions.
SUMMARY OF THE INVENTION
[0010] The inventive subject matter is drawn to various genetically engineered cells, systems, and methods of production of various value products from CO 2 . In most preferred aspects of the inventive subject matter, a cell having a CBB cycle is genetically modified such that two molecules of CO 2 fixed in the CBB cycle can be drawn as a single C 2 compound from the modified CBB cycle without the need for additional recombinant enzymatic activity/activities outside the already existing catalytic activities in the CBB cycle. Viewed from a different perspective it should be recognized that efficient C2 extraction from the CBB cycle can be achieved by only minimally modifying the enzymatic activities in the CBB cycle.
[0011] In addition, the inventors discovered that the so genetically engineered cells are also less prone (or even entirely insensitive) to feedback inhibition of CO 2 fixation in the CBB cycle via reduced phosphoenol pyruvate (PEP) accumulation. Therefore, high quantities of value product can be produced at high CO 2 fixation efficiency by extraction of C2 molecules from the CBB cycle without build-up of PEP. In contrast, an unmodified CBB cycle leads to formation of glyceraldehyde-3-phosphate and subsequently phosphoenolpyruvate (PEP), which was found to inhibit CO 2 fixation and therefore value product formation.
[0012] In one aspect of the inventive subject matter, a method for improving the efficiency of carbon dioxide fixation in an organism having a CBB cycle. Such methods will typically include a step of genetically modifying the organism to produce or overexpress a first enzyme with a phosphoketolase activity, and to produce or overexpress a second enzyme with a phosphoribulokinase activity. In most instances, the first enzyme utilizes an intermediate of the CBB pathway (e.g., fructose-6-phosphate) as a substrate and generates a first acetyl phosphate product, and the phosphoribulokinase activity is produced or overexpressed in an amount to achieve a phosphoribulokinase activity level that is higher than the native phosphoribulokinase activity level (i.e., before genetic modification) of the organism. It is further preferred that the first acetyl phosphate product is converted in the organism to acetyl-CoA.
[0013] In some aspects of the inventive subject matter, the genetically modified organism fixes CO 2 in a medium containing nitrogen (e.g., present as ammonium) in an amount of less than 3 mM. While not limiting to the inventive subject matter, it is also contemplated that the genetically modified organism is further modified to produce from the acetyl-CoA a value added product (e.g., an alcohol, a fuel, a plastic polymer, or monomers suitable for plastic polymer synthesis), and especially PHA, n-butanol, isobutanol, an alkene, or biodiesel.
[0014] In other aspects of the inventive subject matter, the production of PEP in the genetically modified organism is decreased relative to that of a non-modified organism of the same species, particularly under nitrogen limiting or nitrogen depletion conditions. Thus, it is contemplated that the production of PEP in the genetically modified organism, when grown under nitrogen depletion, is below a feedback inhibitory concentration for the CBB cycle. Moreover, it is typically preferred that the produced or overexpressed phosphoribulokinase activity is in an amount that is effective to avoid depletion of ribulose-5-phosphate in the CBB cycle by the phosphoketolase activity.
[0015] Therefore, and viewed from a different perspective, the inventors also contemplate a metabolically engineered cell having a native CBB cycle. Especially contemplated cells will include a recombinant nucleic acid comprising a nucleic acid sequence encoding a first enzyme with a phosphoketolase activity and a second enzyme with a phosphoribulokinase activity, wherein the first enzyme utilizes an intermediate of the CBB pathway as a substrate and generates a first acetyl phosphate product, and wherein the phosphoribulokinase activity is produced or overexpressed in an amount that avoids depletion of ribulose-5-phosphate in the CBB cycle. Most typically (but not necessarily), the metabolically engineered cell is a bacterial cell (e.g., belonging to the genus Ralstonia). Such cells may be characterized in that their production of PEP, when grown under nitrogen depletion, is below a feedback inhibitory concentration for the CBB cycle.
[0016] In further contemplated aspects of the inventive subject matter, the inventors also contemplate a method of reducing PEP in a CBB dependent microorganism under nitrogen limitation condition. Such methods will generally include a step of genetically modifying the microorganism to produce or overexpress a first enzyme with a phosphoketolase activity to thereby generate acetylphosphate from an intermediate of the CBB cycle, and another step of genetically modifying the organism with the CBB cycle to produce or overexpress a second enzyme with a phosphoribulokinase activity, wherein the phosphoribulokinase activity is produced or overexpressed in an amount to achieve a phosphoribulokinase activity level that is higher than the native phosphoribulokinase activity level of the organism. The microorganism is then used to withdraw the acetylphosphate from the CBB cycle via conversion of the acetylphosphate to acetyl-CoA (or downstream value product using acetyl-CoA) to so reduce availability of glyceraldehyde- 3 -phosphate for PEP formation.
[0017] Most typically, the nitrogen limitation condition is characterized by the presence of ammonium in an amount of less than 3 mM, and it is generally preferred that the nitrogen content in the growth medium is controlled such that PEP concentration within the organism is below 0.2 mM. While not limiting to the inventive subject matter, the microorganism is preferably grown in continuous fermentation. Among other suitable value products, various alcohols, biodiesel, alkenes, PHA, or monomers suitable for polymer synthesis are especially contemplated.
[0018] Additionally, it is contemplated that the intracellular concentration of PEP may be further reduced in such cells by overexpres sing an enzyme with a pyruvate kinase activity to convert PEP to pyruvate. Moreover, and where desirable, the cell may be further genetically modified such that the cell has a decreased acetyl-CoA flux into the tricarboxylic acid cycle (TCA cycle), or decreased activities of one or multiple enzymes within the TCA cycle.
[0019] Therefore, the inventors also contemplate a method for producing a value added product in a microorganism having a CBB cycle (e.g., microorganism belonging to the genus of Ralstonia). Most preferably., such method will comprise a step of providing a genetically modified organism having a recombinant first enzyme with a phosphoketolase activity, and wherein the genetically modified organism overexpresses a second enzyme in the CBB cycle having an equilibrium constant of at least 1000. In most aspects, the genetically modified organism produces one molecule of acetyl-CoA through fixation of two molecules of carbon dioxide in the CBB cycle. In a further step, the genetically modified organism is cultured, optionally under low nitrogen conditions, while supplying a source of carbon dioxide, wherein the genetically modified organism uses the acetyl-CoA to produce a value added product (e.g., an alcohol, a fuel, a plastic polymer, or a monomer suitable for plastic polymer synthesis).
[0020] In further aspects of contemplated methods, the source of carbon dioxide may be a combustion product, a flue gas, a fermentation product, a CO 2 enriched gas, an at least partially purified CO 2 gas, a carbonate or bicarbonate solution, an organic acid, and/or formic acid. Moreover, it is contemplated that the step of culturing the genetically modified organism is performed by culturing the organism under nitrogen rich conditions prior to culturing the genetically modified organisms under low nitrogen conditions.
[0021] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWING
[0022] FIG. 1 depicts an exemplary simplified scheme of a modified CBB cycle according to the inventive subject matter.
[0023] FIG. 2 is a more detailed scheme of an unmodified CBB cycle and PEP production therefrom.
[0024] FIG. 3 depicts an exemplary simplified schematic of a modified CBB cycle showing catalytic activity of FPK on xylulose- 5 -phosphate.
[0025] FIG. 4 is a graph depicting exemplary test results in which CO 2 fixation (provided as formic acid) and alcohol production is inversely dependent on nitrogen levels.
[0026] FIG. 5 is a schematic of metabolic pathways illustrating inhibition of the CBB cycle by PEP under nitrogen depletion.
[0027] FIG. 6 is a graph depicting accumulation of intracellular phosphoenolpyruvate (PEP) under various nitrogen depletion conditions.
[0028] FIG. 7 is another schematic of metabolic pathways illustrating inhibition of the CBB cycle by PEP under nitrogen depletion.
[0029] FIG. 8 is a graph illustrating increased electro-autotrophic biofuel production under nitrogen level control to avoid feedback inhibition by PEP.
DETAILED DESCRIPTION
[0030] The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0031] The inventors have discovered systems and methods for genetically engineered cells in which the CBB cycle of an autotrophic organism is altered to derive value-added products directly from a C2 body (e.g., acetyl-CoA) that is directly derived from the modified CBB cycle without the C2 body having been produced via a C3 body (e.g., phosphoenolpyruvate (PEP)). Thus, and viewed from a different perspective, value-added products can be obtained from CO 2 fixation into a C 2 body while at least partially decoupling production of the value added product from PEP. Hence, it should be appreciated that various value-added products can be directly obtained from C2 bodies that are drawn from the CBB without a C1 loss from PEP, which increases the efficiency of CO 2 fixation into such value-added products.
[0032] Moreover, it should be especially appreciated that contemplated cells, systems, and methods advantageously avoid accumulation of PEP within the cell that would otherwise lead to a drastic reduction in production of various value products derived from acetyl-CoA, and particularly where the cell is cultured under nitrogen limitation (e.g., ≦1 mM NH4 + ). Indeed, the inventors also discovered that nutrient (and especially nitrogen) limitation leads to an accumulation of PEP within the cell that in turn leads to a reduced CO 2 fixation via the CBB cycle, and with that substantially decreased pyruvate/acetyl-CoA quantities that would otherwise be available for production of value products from CO 2 fixation. Viewed from a different perspective, it should be noted that genetically modified organisms contemplated herein produce one molecule of acetyl-CoA through the fixation of two molecules of CO 2 without losing fixed carbon as CO 2 in the process.
[0033] This and other advantages can be accomplished by genetically modifying an organism that utilizes the CBB cycle to express an enzyme activity that utilizes fructose- 6 -phosphate as a substrate and generates acetylphosphate, an acetyl-CoA precursor, as a product. Among other suitable enzymes, enzymes with phosphoketolase activity are especially suitable as they will utilize fructose-6-phosphate as a substrate and produce acetylphosphate and erythrose-4-phosphate. However, enzymes expressing such activity frequently can also utilize xylulose-5-phosphate as a substrate and can therefore potentially deplete the CBB cycle of ribulose-5-phosphate utilized in CO 2 capture. Surprisingly, the inventors have found that this depletion can be avoided by engineering the autotrophic organism to overexpress enzymatic activity that utilizes ribulose-5-phosphate as a substrate to produce ribulose-1,5-diphosphate as is exemplarily and schematically illustrated in the simplified scheme for the modified CBB cycle of FIG. 1 . Here, the overall reaction for CO2 fixation into the CBB cycle follows the equation 2 CO2+6 ATP+4 NADPH→1 Acetyl-CoA. In FIG. 1 , FA is fructose-1,6-bisphosphate, SA is sedoheptulose-1,7-bisphosphate aldolase, TK is transketolase, PRK is phosphoribulokinase, FPK is F 6 P phosphoketolase, and RB is RuBisCo. As can be readily seen, two C1 molecules (CO 2 ) are fixed onto two C5 molecules (ribulose-1,5-bisphosphate) and the reaction products are then turned over in the engineered CBB pathway to produce one C2 molecule (acetyl-CoA) and a byproduct that forms part of the CBB cycle.
[0034] In that context, it should be noted that incorporation of two C1 molecules of CO 2 is accompanied by the formation of a product that leads to acetyl-CoA (and hence to value added products) through the F 6 P activity of phosphoketolase, via a metabolic pathway that does not lead to downregulation of the CBB cycle as a substantial amount of carbon entering the CBB cycle is withdrawn as a C 2 product (acetylphosphate) as opposed to a C3 product (glyceraldehydes-3-phosphate) that would otherwise require transformation to acetyl-CoA (e.g., via oxidative decarboxylation). For example, acetylphosphate can be converted to acetyl-CoA phosphotransacetylase or phophate acyl transferase (EC 2.3.1.8; which may be native to a cell or be recombinant). It should be noted, however, that the C3 products produced through CO 2 fixation by RuBisCo during the process can also lead to at least some degree to acetyl-CoA (and hence to value added products). Inventors therefore believe that the increased carbon fixation efficiency can result in improved growth and production of value added products (for example alcohols, biofuels, PHA, monomers suitable for use in plastic production, and/or plastic polymers) in autotrophs with such a modified CBB cycles.
[0035] FIG. 2 illustrates a more detailed view of an unmodified CBB cycle in which CO 2 is fixed by RuBisCo (not shown) utilizing ribulose- 1 , 5 -biphosphate to produce 3-phospho-glycerate, a precursor to PEP and pyruvate used in the synthesis of value added compounds. When coupled with glycolysis, the overall CO 2 fixation reaction follows the equation: 3 CO2+7 ATP+4 NADPH→Acetyl-CoA. With further reference to FIG. 2 it should be noted that the CBB cycle utilizes xylulose-5-phosphate in the generation of ribulose-5-phosphate that is then further phosphorylated by a ribulokinase to finally form the CO 2 acceptor ribulose-1,5-bisphosphate. As noted above, addition of recombinant phosphoketolase will advantageously produce a C2-compound plus erythrose-4-phosphate. Unfortunately, the phosphoketolase can also utilize compounds other than fructose 6-phosphate as substrates, and particularly xylulose-5-phosphate leading to depletion of ribulose-5-phosphate, which in turn depletes ribulose-1,5-bisphosphate. This activity can thus have the undesirable effect of reducing CO 2 fixation.
[0036] The inventors have now discovered that the adverse effect of undesirable xylulose-5-phosphate activity of the recombinant phosphoketolase can be reduced or even eliminated through overexpression of phosphoribulokinase having an enzymatic activity that is already present in the CBB cycle (catalyzing formation of ribulose-1,5-bisphosphate from ribulose-5-phosphate). As used herein, ‘overexpression” of a gene means expression of that gene to form a gene product in an amount such that the amount is greater than zero or in an amount that is greater than an amount that would otherwise be already present in the cell without the overexpression.
[0037] As can be seen in FIG. 2 , xylulose-5-phosphate is in an equilibrium with ribose 5-phosphate. However, in a practical sense, ribulose-5-phosphate is clearly not in equilibrium with ribulose-1,5-bisphosphate as the conversion of ATP to ADP in that reaction provides a significant barrier to the reverse reaction. Indeed, phosphoribulokinase could be considered to have an equilibrium constant of at least 1000, and as such to catalyze the formation of ribulose-1,5-bisphosphate in an almost unidirectional manner. Consequently, it should be appreciated that overexpression of phosphoribulokinase will result in depletion of ribulose-5-phosphate, which in turn leads to depletion of ribose 5-phosphate. This depletion of ribose 5-phosphate shifts the equilibrium between ribose-5-phosphate and xylulose 5-phosphate, and therefore reduces the amount of xylulose-5-phosphate available to act as a substrate for phosphoketolase, effectively reducing this activity (i.e., through substrate competition) while not impacting the production of ribulose 1,5-bisphosphate necessary for CO 2 fixation. Thus, overexpression of phosphoribulokinase will substantially irreversibly drain ribulose-5-phosphate to ribulose-1,5-bisphosphate to thereby keep xylulose-5-phosphate low. Viewed from a different perspective, the reaction sequence to regenerate ribulose 1,5-bisphosphate is therefore ‘pulled’ through ribose-5-phosphate to ribulose-5-phosphate rather than through xylulose 5-phosphate. FIG. 3 depicts a simplified schematic of a modified CBB cycle with no overexpression of phosphoribulokinase illustrating the effect of the phosphoketolase on fructose-6-phosphate (FRK) and xylulose-5-phosphate (XPK).
[0038] Of course, it should be appreciated that the overexpression of the phosphoribulokinase could also be replaced or supplemented by native or recombinant expression of a mutant form of phosphoribulokinase that exhibits a substrate specificity towards fructose-6-phosphate. For example, suitable mutant forms will have a substrate specificity of fructose-6-phosphate versus xylulose-5-phosphate (e.g., as measured by K m ) of at least 5:1, more preferably at least 10:1, even more preferably at least 100:1, and most preferably at least 500:1.
[0039] Therefore, an alternate and stable CBB pathway is provided that utilizes the fixation of two molecules of CO 2 to produce 1 molecule of acetyl-CoA, compared to three molecules of CO 2 via the native CBB cycle, thereby improving the efficiency of CO 2 conversion into value-added products otherwise derived from PEP (and/or other C2 metabolites derived from the CBB cycle) at least conceptually from 66% to 100%. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0040] Phosphoketolase, EC 4.1.2.9, can be found in numerous sources, and cloning and stable or transient expression will follow generally well-known laboratory protocols using appropriate vectors. For example, phosphoketolase is known from Lactobacillus (see e.g., J Microbiol Biotechnol. 2007 May; 17(5):822-9), Bifidobacterium breve (see e.g., BMC Genomics. 2014 Mar. 1; 15:170), Bifidobacterium adolescentis (see e.g., Appl Microbiol Biotechnol. 2009 July; 83(6):1115-26), Acetobacter xylinum (see e.g., J Biol Chem. 1958 December; 233(6):1283-8), Bifidobacterium longum (see e.g., Lett Appl Microbiol. 2001 April; 32(4):235-9), etc. Likewise, phosphoribulokinase EC 2.7.1.19 is well known and can be cloned from numerous sources, and cloning and stable or transient expression will follow generally well-known laboratory protocols using appropriate vectors. For example, phosphoribulokinase can be cloned from Arabidopsis thaliana (see e.g., J Exp Bot. 2005 January; 56(409):73-80), Rhodobacter sphaeroides (see e.g., Protein Sci. 2006 April; 15(4):837-42), etc. In some embodiments of the inventive concept, it is contemplated that the overexpression can reduce the apparent xylulose-5 phosphate activity of a phosphoketolase by at least 50%, or by at least 60%, or at least 70% relative to the activity observed in a similar organism that does not overexpress phosphoribulokinase.
[0041] In a still further notable aspect of the inventive subject matter, withdrawal of the fixed CO 2 via C2 compounds form the CBB cycle has a further benefit in avoiding accumulation of PEP in the cell to a level that would otherwise inhibit CO2 fixation in the CBB cycle. Thus, not only is CO 2 fixation more effective, but can also lead to higher cell densities and yield for value products produced from acetyl-CoA. In other words, the inventors have surprisingly discovered that the CBB cycle can also be modified to reduce or even eliminate the effect of nitrogen depletion on carbon fixation as is described in more detail below.
[0042] Production of value added products by microorganisms capable of fixing carbon is typically performed in culture, with the provision of various nutrients as necessary to support growth and metabolism of autotrophic organisms. Such nutrients include nitrogen, often in the form of ammonia or an ammonium salt. The concentration of such nutrients can be controlled in order to modulate the growth and/or metabolic state of the cultured autotrophs. For example, nitrogen in the form of an ammonium salt can be provided at nitrogen depletion concentrations (i.e., 1 mM NH 4 + or less), low nitrogen concentrations (i.e., from 2 mM to 4 mM NH 4 + ), and nitrogen rich (e.g., ≧10 mM NH 4 + ). Nitrogen rich conditions can support rapid growth and accumulation of biomass of the microorganism, but may not be ideal for production of value added products as most of the nutrients are fed to oxidative glycolysis. On the other hand, nitrogen depletion conditions may not support growth of cultured microorganisms but can increase the production of value added products.
[0043] This phenomenon can be exploited to improve the efficiency of the production of, for example, alcohols by initially providing a nitrogen rich environment to grow the autotrophs to the desired density then reducing the nitrogen concentration in the culture media to nitrogen depletion conditions. Results of such a process are shown in FIG. 4 , in which cells were grown at 15 mM NH 4 + for 32 hours, at which point the concentration of NH 4 + was reduced to less than 1 mM. In this instance CO 2 was provided in the form of formic acid and the value added product produced was a higher alcohol (for example, isobutanol). While this approach enhances production of the value added product to at least some degree, it can also be clearly seen that the fixation of CO 2 in the form of formic acid decreases dramatically shortly after nitrogen depletion conditions are established. Such decrease is undesirable as this decrease in carbon fixation limits the capacity for synthesis of value added products.
[0044] Without wishing to be bound by any theory or hypothesis, the inventors believe that such decrease is due, at least in part, to the accumulation of C3-precursors of the value added products, and especially PEP. One mechanism by which this can occur is shown in FIG. 5 . As can be seen in FIG. 5 , CO 2 fixation in an unmodified CBB cycle (CBB) results in the production of phosphoenolpyruvate (PEP), which can be utilized in the synthesis of added value products isobutanol (IBOH) and PHA via pyruvate and Acetyl-CoA, respectively. PEP is also in equilibrium with oxaloacetate produced as part of the citric acid cycle. Nitrogen depletion conditions can lead to an accumulation of alpha-ketoglutarate (2 KG) produced in the citric acid cycle through decreased synthesis of glutamic acid. This can, in turn, lead to elevated concentrations of oxaloacetic acid, which leads to increased production of PEP via the equilibrium reaction. Since PEP can down-regulate enzymes of CBB cycle (PEP-cBBR inhibits PcbbL promoter, which express the cbbL operon; the cbbL operon encodes the Rubisco large subunit and Rubisco small subunit 2), nitrogen depletion conditions can result in decreased carbon fixation via the CBB cycle. Therefore, a paradoxical situation will arise in which the same conditions that favor production of value products from CO 2 fixation over cell growth (i.e., low nitrogen levels) are also material in the throttling down of the CBB cycle that is used to generate the value products.
[0045] FIG. 6 exemplarily depicts intracellular PEP concentration as a function of nitrogen levels in the growth medium for two Ralstonia strains (WT: wildtype; LH44N: isobutanol production strain with deleted PHA production pathway) without modified CBB cycle. Both strains were grown under nitrogen rich (N-rich: NH4 + >10 mM), low nitrogen (N-low: NH4 + approximately 3 mM in continuous run), and nitrogen depletion (N-depletion: NH4 + <1 mM) conditions. Also indicated by the dashed line is the threshold where inhibition of the CBB cycle by PEP was experimentally observed. Here, the observed increase in intracellular PEP is consistent with concentrations necessary for down-regulation of CBB cycle enzymes, which in turn is consistent with the observed loss of carbon fixation under nitrogen depletion conditions.
[0046] Therefore, the inventors also contemplate growth and production conditions for cells having a CBB cycle (which may be modified as described above or unmodified) in which the intracellular concentration of PEP is maintained below threshold of about 0.2 mM. In most cases, this can be achieved by maintaining the ammonia concentration in the medium at a level of about 3 mM or below, which may be advantageously achieved using a continuous fermentation protocol.
[0047] As already noted above and further illlustrated in FIG. 7 , the accumulation of PEP could be explained by the hypothesis that the nitrogen limitation induced shutdown of TCA cycle could further increase intracellular concentration of OAA and acetyl-CoA, and eventually pyruvate and PEP, since there is no PHA production pathway in the engineered R.eutropha strain LH 47 N. The inhibition of CBB could stop the fixation of CO 2 and the formate consumption, therefore ceasing the isobutanol production. It needs to be highlighted that PEP does not affect the consumption of fructose because the glycolysis is not inhibited by PEP. Therefore, the nitrogen limitation induced PEP accumulation does not affect the production of isobutanol from fructose. This result sheds new light on the observation that the production strains could produce isobutanol efficiently from fructose, but not from formate.
[0048] Taken together, the engineered production Ralstonia has an AlsS protein to convert pyruvate to acetolactate for isobutanol production. The AlsS's Km value for pyruvate is 7 mM. Therefore, AlsS could only efficiently consume pyruvate when pyruvate concentrations are relatively high. However, high pyruvate concentrations will induce PEP accumulation. To solve this problem without modificaiton of the CBB cycle, the inventors used a continuous fermentation process during which the chemical environment inside the fermentor is static (chemostat). Fresh medium was continuously added, while culture liquid was continuously removed to keep the culture volume constant. By changing the rate with which medium is added to the bioreactor, the growth rate of the microorganism can be controlled. During the fermentation process, the concentration of ammonium in the broth was maintained around 3 mM. The EB-074 cells grown in N-limitation medium had intracellular PEP concentrations less than 0.1 mM. That is to say, EB-074 did not accumulate a significant amount of PEP inside the cells under continuous fermentation conditions when formate was used as the sole carbon source. Formate consumption and formate concentration in the fermentation vessel were stable during the 34 day run as well. As can be seen from FIG. 8 , the maximum captured electro-autotrophic biofuel reached 5.6 g/L under continuous fermentation with continuous feeding of (NH 4 ) 2 SO 4 so that its concentration is around 200 mg/L (3 mM NH4 + ). This resulted in low nitrogen conditions, which avoid PEP accumulation, and which in turn avoids CBB inhibition, resulting in continuous high level production.
[0049] It should be recognized that the production conditions could also be performed with cells having a modified CBB cycle as descibed above as such cycle advantageously also at least partially decouples the synthesis of value added products from the generation of PEP. This decoupling can reduce or eliminate the need to generate high concentrations of PEP and the subsequent down-regulation of cbb gene expression.
[0050] Modification of the CBB cycle in a microorganism were performed following standard recombinant cloning protocols known in the art. In one exemplary and typical modification, plasmids for expressing Phosphoketolase (F/XPK) and phosphoribulokinase (PRK) were constructed using pQE9 (Qiagen) as the vector backbone. The expression of F/Xpk and PRK in their corresponding plasmids in Ralstonia were under the control of the PLlacO1 promoter. The genomic template for F/Xpk was from B. adolescentis ATCC 15703, and the genomic template for PRK was from Synechocystis sp. PCC 6803 Improved acetyl-CoA/value product formation in the so modified Ralstonia was observed using standard techniques.
[0051] The conjugation and transformation methods were used as the genetic tool to alter the pathway in Ralstonia. The wild-type PHB biosynthesis genes in the Ralstonia production strain were knocked out by chromosomal replacement while a chloramphenicol acetyltransferase (CAT) cassette was inserted. E.coli genomic DNA was used to clone the plasmid containing alsS, ilvC, and ilvD genes. The purified plasmid was transformed into an E.coli conjugation strain (referred to as the donor strain). The donor strain containing the desired plasmid and the recipient Ralstonia strain are incubated together on an agar plate. The alsS-ilvC-ilvD operon was transferred from the donor to the chromosome of the recipient Ralstonia strain via double crossover. To produce isobutanol, the kivd-yqhD operon was constructed into a plasmid which was introduced into the above Rasltonia strain through transformation. The genes kivd and yqhD were purified from Lactococcus lactis and E. coli genomic DNA, respectively. The yqhD gene was chosen to be the alcohol dehydrogenase because it is NADPH dependent and there is an abundant NADPH supply in the cell.
[0052] To test the performance of the engineered Ralstonia production strain, formate-based autotrophic bench-scale fermentations were performed. The formate-based fermentation used 1.8 L J minimal medium cultured with the production strain in a 5 L fermentor J minimal medium contains 1 g/L (NH4) 2 SO 4 , 0.5 g/L KH 2 PO 4 , 6.8 g/L NaHPO 4 , 4 mg/L CaSO 4 -2H 2 O, 100 ug/ 1 thiamine hydrochloride, 0.2 g/L MgSO 4 -7H 2 O, 20 mg/L FeSO 4 -7H 2 O, and 1 ml/L SL7 metals solution (SL7 metal solution contains 1% v/v 5M HCl (aq), 0.1 g/L MnCl 2 -4H 2 O, 1.5 g/L FeCl 2 -4H 2 O, 0.19 g/L CoCl 2 -6H 2 O, 0.036 g/L Na 2 MoO 4 -2H 2 O, 0.07 g/L ZnCl 2 , 0.062 g/L H 3 BO 3 , 0.025 g/L NiCl 2 -6H 2 O, and 0.017 g/L CuCl 2 -2H 2 O). Agitation, temperature, pH, and dissolved oxygen content (DO), air flow % and O2 flow % set points were held at 300 rpm, 30° C., 7.2, 5%, 100%, and 0%, respectively. Gas flow was controlled using a dynamic-control cascade that varied the gas flow rate based on the DO reading. Formic acid was added in small increments to prevent the protonated acid molecules from penetrating the cell membrane and acidifying the cytoplasm. The formic acid feed rate was coupled to changes in pH. A pH-driven cascade controller pumps in formic acid when the pH levels are elevated. This replenishes carbon levels as the formate is consumed by the cells. Graham condenser was used to collect the evaporated alcohols from gas vented from the fermentor. Every 24 hours, samples of culture broth and liquid condensed from the vented gas were collected, characterized, and quantified using gas chromatography (GC).
[0053] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. As also used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Likewise, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc. | Genetically engineered cells and methods are presented that allow for the production of various value products from CO 2. Contemplated cells have a CBB cycle that is genetically modified such that two molecules of CO 2 fixed in the CBB cycle can be withdrawn from the modified CBB cycle as a single C2 compound. In contemplated aspects a CBB cycle includes an enzymatic activity that generates the single C2 compound from a compound of the CBB cycle, while further modifications to the CBB cycle will not introduce additional recombinant enzymatic activity/activities outside the already existing catalytic activities in the CBB cycle. |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based on U.S. Provisional Application Ser. No. 60/439886, entitled “Homogenizer for Collimated Light With Controlled High Angle Scatter”, filed on Jan. 14, 2003, the teachings of which are incorporated herein by reference.
TECHNICAL FIELD
The present invention relates to efficiently homogenizing collimated light entering a light guide and more specifically to backlighting a liquid crystal display (LCD).
BACKGROUND OF THE INVENTION
It is known that the use of a collimated backlight and a front diffusing screen can greatly improve the quality of an LCD. One such approach is described in Saccomanno (U.S. Pat. No. 6,428,198), which is incorporated herein by reference. Saccomanno describes the use of an arc lamp, whose light is collected, homogenized, and coupled into an array of optical conduits. Each conduit then illuminates a non-imaging optic, which collimates the light and subsequently illuminates the edge of a light-extraction guide.
Even though my prior patent teaches an effective collimated light and diffuser screen arrangement, for certain applications such as medical imaging there is a need to improve black-level contrast and image sharpness even at the expense of a slightly larger and less light efficient device.
SUMMARY OF THE INVENTION
In accordance with my present invention, a mild diffuser, having controlled scattering angles, is placed at the input aperture of a slab light guide. This mild diffuser is inserted between the collimation source (e.g. non-imaging optics) and the light extraction guide. Unlike the diffusers that have been previously used in diffuse backlights, the diffuser in accordance with my invention has a controlled scattering angle of less than about eight degrees and most advantageously of less than +/−5 degree full-width half-maximum (FWHM) scatter and is referred to herein as a ‘mild diffuser’ to contrast it from the prior art diffuser arrangements. The slab light guide further serves to homogenize the collimated beam. The slab light guide may be a separate element from the light extraction guide or the light extraction guide may have a “lead-in” portion that comprises a homogenizing slab section.
This homogenizer technique is especially useful in overcoming irregularities due to periodic structures that supply the source of collimated light. Since any diffuser will naturally increase the overall beam divergence, an optical constraining layer, having a refractive index slightly less than the refractive index of the slab light guide, is positioned on one or more outer surfaces of the slab light guide. A light absorbing black layer is then positioned on the optical constraining layer or layers, the light absorbing layer having a higher refractive index than the slab light guide and the optical constraining layer. The result of this combination is that the slab light guide now can strip out high angle light.
Such high angle light will cause increasing fuzziness between adjacent pixels and also cause a net lowering of the black-level contrast; this effect is described in Yamaguchi (U.S. Pat. No. 6,421,103). The light exiting the slab light guide is thus homogenized and stripped of high-angle light and can be fed into the light extraction guide, providing a uniform output.
DESCRIPTION OF THE DRAWING
FIG. 1 illustrates a homogenizer in accordance with one illustrative embodiment of the present invention.
FIG. 2 illustrates a homogenizer in accordance with my invention in combination with a wedge shaped light extraction guide.
DETAILED DESCRIPTION OF THE INVENTION
Referring first to FIG. 1 , an acrylic (although other optical quality materials may be used) slab light guide 12 , having a first refractive index, is covered on its top surface 43 with an optical constraining layer 15 , such as an acrylic pressure sensitive adhesive (PSA). A type of PSA that is suitable for my invention is Rexam OCAV3. The optical constraining layer 15 has a second refractive index, which is slightly less than the refractive index of the slab light guide 12 . In one embodiment of my invention, the acrylic slab light guide 12 has a refractive index of 1.4893 while the optical constraining layer 15 has a refractive index of 1.4800.
Because of the slight difference in refractive index, the optical constraining layer 15 acts to trap light within the light guide under certain conditions. Accordingly, collimated light that enters the acrylic slab light guide 12 at surface 41 through a mild diffuser 11 with an angular spread below a certain threshold value is contained within the slab light guide 12 by total internal reflection (TIR). Light with an angular spread above the threshold value exits the slab light guide 12 and enters the optical constraining layer 15 . In embodiments of my invention using PSA as the optical constraining layer 15 , it also mechanically functions to adhesively fasten an optical absorbing layer 16 , such as for example, Dupont Kapton CB black polyimide, to the slab light guide 12 , forming a sandwich structure therewith.
In other embodiments of my invention the optical absorbing layer is disposed on the optical constraining layer, for example, in certain embodiments, the optical constraining layer 15 is a thin film coating on the acrylic slab 12 and the optical absorbing layer is a black paint overcoat, such as for example Krylon Ultra-Flat or Tetenal Kameralack. Note that the optical constraining layer must be thick enough, for example three wavelengths of light, so that the total internally reflected light is not inadvertently absorbed due to the evanescent aspect of light reaching the black layer.
The optical absorbing layer 16 has a refractive index that is greater than the refractive index of optical constraining layer 15 . This difference in refractive indices causes the light within the optical constraining layer 15 , that is, the light that has not been contained by TIR within the light guide, to exit into the optical absorbing layer 16 where it is absorbed.
Advantageously, the mild diffuser allows for the mixing of discrete collimated light sources, such as non-imaging collimators 22 that are optically driven from optical fibers 21 . Suitable mild diffusers are available from Reflexite (Avon, Conn.), part numbers BP336, BP302 and BP321 having symmetric half angles of +/−3.9 degrees, +/−3.8 degrees, and +/−2.8 degrees, respectively. From lab testing, it has been determined that BP321 is preferred when used in combination with a “SolarTec CL Light” fiber optic illuminator from Wavien, Inc. (Santa Clarita, Calif.), ESKA SK60 fibers from Mitsubishi Rayon Co. (Tokyo, Japan), and Poly II acrylic from Polycast (Stamford, Conn.). In other embodiments of my invention, the mild diffuser 11 is embossed on the entrance aperture of the slab light guide 12 .
Light that is angularly limited below the threshold limit passes through the slab light guide 12 and exits at surface 42 . Advantageously, this angularly limited collimated light is especially suitable for a wedge light extraction guide 23 as may be found behind a liquid crystal display (LCD).
In certain embodiments of my invention, the lower surface 44 of the slab light guide 12 has a second optical constraining layer 17 and a second optical absorbing layer 18 disposed thereon. These optical layers function in the same manner as previously described optical constraining layer 15 and optical absorbing layer 16 .
Referring now to FIG. 2 , there is depicted another illustrative embodiment of the present invention. In this embodiment, the mild diffuser, slab light guide, and wedge light extraction guide are fashioned from the same monolithic substrate 50 , preferably acrylic. The monolithic substrate 50 comprises two distinct regions, a constant cross-section slab light guide region 61 and a wedge-shaped light extraction guide region 62 . The light enters the slab light guide region 61 through an embossed entrance diffuser 51 . Similar to the previous embodiment, the slab light guide region 61 includes an upper surface 53 and a lower surface 54 .
The upper surface 53 and the lower surface 54 are covered with optical constraining layers 15 and 17 , respectively as in the prior embodiment. The optical constraining layers 15 and 17 each have a second refractive index, which is slightly less than the refractive index of the monolithic substrate 50 . Because of the slight difference in refractive index, the optical constraining layers 15 and 17 act to trap light within the slab light guide region 61 under certain conditions. Accordingly, collimated light that enters the monolithic substrate 50 through embossed entrance diffuser 51 with an angular spread below a certain threshold value is contained within the monolithic substrate 50 by total internal reflection (TIR). Light with an angular spread above the threshold value exits the monolithic substrate 50 and enters the optical constraining layers 15 and 17 .
Disposed on the optical constraining layers 15 and 17 are optical absorbing layers 16 and 18 , respectively. The optical absorbing layers 16 and 18 each have a refractive index that is greater than the refractive index of optical constraining layers 15 and 17 . This difference in refractive indices causes the light within the optical constraining layers 15 and 17 , that is, the light that has not been contained by TIR within the monolithic substrate 50 , to exit into the optical absorbing layers 16 and 18 , where it is absorbed.
Table 1 below details results of the Snell's law calculations for a certain illustrative embodiment of my invention comprising a 6-millimeter thick acrylic slab with a refractive index of 1.4893, and an optical constraining layer formed from a PSA with a refractive index of 1.4800. These calculations detail input light angles from 5 to 23 degrees in air. The calculations show that light with a divergence angle of greater than 10 degrees is absorbed. Also shown in Table 1 is the minimum slab length required for the input light to have at least one reflection into the optical constraining layer. For example, for light having angles 10 degrees and greater to get absorbed the slab length needs to be at least two inches long.
TABLE 1
Input
Light Angl
Minimum
Light Angle
Light Angle
within slab ( )
Slab Length
into PSA
(degrees)
(degrees)
(mm)
(degrees)
5.0000
3.3549
102.36
TIR
6.0000
4.0247
85.28
TIR
7.0000
4.6938
73.08
TIR
8.0000
5.3620
63.93
TIR
9.0000
6.0294
56.81
TIR
10.000
6.6958
51.11
88.049
11.000
7.3610
46.45
86.367
12.000
8.0249
42.56
85.157
13.000
8.6875
39.27
84.120
14.000
9.3486
36.45
83.177
15.000
10.008
34.00
82.295
16.000
10.666
31.86
81.455
17.000
11.322
29.97
80.646
18.000
11.976
28.29
79.861
19.000
12.627
26.79
79.096
20.000
13.277
25.43
78.347
21.000
13.924
24.21
77.612
22.000
14.568
23.09
76.889
23.000
15.210
22.07
76.176
ALTERNATE EMBODIMENTS
Alternate embodiments may be devised without departing from the spirit or the scope of the invention. For example, an array of collimated light emitting diodes (LED) or low numerical aperture fibers can be ass input sources in lieu of the non-imaging collimated light sources comprising collimators 22 and optical fibers 23 . Also, the light guides need not be solid, but can be hollow by use of TIR films, such as that described in Whitehead (U.S. Pat. No. 4,260,220). | A homogenizer for collimated light limits the angular distribution of the light by passing the light through a mild diffuser followed by a slab light guide which has top and bottom surfaces covered with optical constraining layers and optical absorbing layers where the optical absorbing layer has a higher refractive index than the optical constraining layer and the optical constraining layer has a lower refractive index than the slab light guide. |
FIELD OF THE INVENTION
[0001] This invention generally relates to structures reinforced with fibers which attribute the material, in addition to material reinforcement, also with at least one property, such as fire retarding and anti-biofouling characteristics; and processes for the manufacture of such structures.
BACKGROUND OF THE INVENTION
[0002] With the increasing applications of fibers for reinforcement of constructive elements, short cut (3-40 mm) fibers of high content and great surface area (diameters within the range of 1-40 micrometers) have been dispersed in concretes, asphalts and plastics for effective reinforcement performance (1-3).
[0003] Modification of the aforementioned fibers with novel chemistry, special structure/properties and innovative architecture of reinforcement, brings about effective upgrading of various properties of the matrix that they reinforce.
[0004] Accordingly, such fibers may be used for upgrading other properties of the matrix in addition to structural reinforcement, functioning as additives for protection of the matrix (admixtures) against chemical and biological corrosion and fire.
[0005] There have been several commercial applications of fibers as additives in concretes, asphalts, plastics and yams/fabrics for the above purposes. Some of which include:
polypropylene and Nylon fibers have been heavily used to protect concretes against fire (4). biocides containing fibers have been used for the protection against bacteria and microorganisms in concretes (5). membranes are protected by biocides against bio fouling (6).
REFERENCES
[0009] (1) U.S. Pat. No. 5,399,195
(2) AFS Advanced Fibers Solution Inc., Asphalt Fibers Technical Data Sheet
[0010] (3) Fiber-reinforced composites: materials manufacturing and design, P.K Patrick, 1988, M. Dekker
(4) Adfil Construction Fibers, Ignis Fire protection fibers Technical Data Sheet
(5) U.S. Pat. No. 6,162,848
(6) U.S. Pat. No. 6,540,915
SUMMARY OF THE INVENTION
[0011] The technology being at the core of the present invention relates to the use of novel fibers in the construction of reinforced elements and methods for their preparation. The fibers effectively upgrade the inherent properties of the elements, as specified below.
[0012] The high content fibers of the invention are designed to protect the elements in which they are present, in accordance with the invention, via chemical and biological agents they contain. The agents interact effectively with the hazardous elements at the surface, and/or in the bulk of the matrix of the reinforced elements via direct contact of the fibers with the hazardous elements at the surface (high surface concentration of the fibers), or controlled release of the agents from the fibers, that diffuse to the hazardous elements.
[0000] A. Protection Via Surface Interaction of the Fibers with the Environment
[0013] It is a purpose of the present invention to provide a structure reinforced with a plurality of polymeric fibers protruding from at least a portion of the structure surface surface, the fibers being capable of endowing (attributing) the at least a portion of the surface with biological or chemical resistance. In some embodiments, the polymeric fibers, as further disclosed hereinbelow, contain or are coated with at least one biological or chemical agent which further contributes to the endowment of biological or chemical resistance.
[0014] The invention also provides a fire-resistant structure reinforced with a plurality of polymeric fibers, optionally protruding from at least a portion of its surface. In some embodiments, a fire-resistant structure is provided in which the plurality of polymeric fibers protrude from at least a portion of its surface. In other embodiments, in a fire-resistant structure reinforced with a plurality of polymeric fibers, the fibers are at the at least a portion of the surface, e.g., substantially not protruding from the surface.
[0015] As disclosed herein, the invention contemplates a great variety of structures which are attributed with at least one property which the material (out of which the structure is made, absenting the fibers reinforcing it) is devoid of The structures of the invention may therefore be utilized in a great variety of applications, as will be further disclosed hereinbelow.
[0016] Within the context of the present application, the structure has a surface which may be external to the structure (namely exposed outwards to an environment) or an inner surface (namely exposed inwards into a cavity or channel within said structure) holding or being in contact with a certain environment. The structure, in accordance with the invention, may also be made of a hybrid material wherein the body (bulk) of the structure is of a first material while its surface is a coating of the same or a different material.
[0017] The structure is typically three-dimensional (element) which at least a portion of its surface is prone to one or more fully or partially destructive conditions which are associated with the environment to which it is exposed; the surface sensitivity to such conditions may be associated with the structure material, the conditions under which the structure is used, etc.
[0018] The structure may be made of a single material or a mixture of materials. Non-limiting examples of such materials include a plaster material, a cementitious material, a mortar, concrete, a polymeric material, plastic, a fabric, a yam, a carbonaceous material, a paper material, a woven textile, a non-woven textile, a knitted textile, asphalt and others.
[0019] To increase its resistance to the destructive conditions associated with its final application or conditions under which the structure is employed, the surface of the structure is provided with a plurality of polymeric fibers, which may be of a single type of material or fibers of different materials and different mechanical and/or chemical characteristics, endowing its surface, and therefore the structure as a whole, with the required resistance. In accordance with the present invention, and depending on the application, the surface need not be fully coated with the plurality of polymeric fibers. In some embodiments, the complete three-dimensional surface of the structure is provided with the plurality of fibers. In other embodiments, only a portion of the surface is provided with the fibers; the portion of the surface may be substantially a two-dimensional (flat) surface, or a three-dimensional (non-flat) surface of the structure. The at least one portion of the surface may be one or more portions (regions) of the surface which are spaced apart (not connected with each other). The regions may be spaced apart in a predetermined pattern or may be randomly distributed. For example, where the structure is in the form of a tube, only its inner surface may be provided with a plurality of polymeric fibers.
[0020] In some embodiments, the structure may be in a form selected from tubing, a block, a flat element, a corrugated element, a container, and others. In some embodiments, the tubing element is a liquid communication element such as a water pipe, a waste conduit, a manhole, pumping tubing, water reservoir, pool and pond, pier, deck wave breakers, a desalination element and others as known in the field.
[0021] For certain applications, the structure of the invention is constructed to expose on its surface a plurality of polymeric fibers containing or being coated by an agent, i.e., a biological or a chemical agent, which is capable of endowing the surface of the structure with one or more property, as further disclosed below, or by endowing a property which the fibers themselves lack. Therefore, the polymeric fibers may be pre-treated to contain the biological or chemical agent by incorporating said agent into the polymeric fibers during their production stages, or alternatively, by coating the outer surface of the fibers by said agent.
[0022] The polymeric fibers are discrete elongated pieces of one or more polymeric materials, the fibers having a typical diameter of between about 1 and 40 micrometers, and in some embodiments of between about 1 and 30 micrometers. In some embodiments, the diameter is between about 5 and 25 micrometer, or between about 10 and 40 micrometer, or between about 20 and 40 micrometer or between about 15 and 25 micrometer.
[0023] The thickness of the fibers may alternatively be measured in decitex (dtex) units for fineness of fibers. In some embodiments, the thickness of the polymeric fibers is selected to be between about 0.01 to 10.0 dtex per fiber. In some embodiments, the thickness is between 1.0 and 6.0 dtex per fiber.
[0024] In further embodiments, the polymeric fibers are between about 2 and 80 millimeters in length, or between about 2 and 45 millimeters in length, or between about 10 and 45 millimeters in length, or between about 25 and 45 millimeters in length, or between about 2 and 36 millimeters in length, or between about 2 and 20 millimeters in length, or between about 10 and 20 millimeters in length.
[0025] The polymeric fibers may be made of any polymeric material or mixtures thereof. In some embodiments, the fibers are made of a. polymer selected from polyamides, polyethylene terephthalate, polybutylene terephthalate, polyacrylonitrile, polyvinyl alcohol, polypropylene, polyethylene and poly lactic acid. In some embodiments, the polymeric fibers are of a polyimide, such as Nylon 6 and Nylon 6.6.
[0026] In some embodiments, the fiber is selected from melt spun polymers and wet spun polymers.
[0027] In some embodiments, the melt spun polymer is selected amongst Nylons, polyesters, polypropylene, polyethylene, polyolefines, and poly(lactic acid). In some cases, the melt spun polymer is in the form of a partially oriented yarn (POY) made of a polymeric material selected from Nylon 6.6, Nylon 6, polyesters, polypropylenes, polyolefines, and poly(lactic acid).
[0028] In some embodiments, the POY is characterized by a tenacity range of 2.5 and 4.5 grams/dtex and an elongation range of 60%-130%.
[0029] The melt spun polymer may be in the form of a fully drawn yarn of a material selected from Nylon 6.6, Nylon 6, polyesters, polypropylenes, and polyolefines. In some embodiments, the yarn is characterized by a tenacity range of 4.6-9.0 grams/dtex and an elongation range of 5%-59%. In some embodiments, the tenacity range is of 5.0 and 7.0 grams/dtex and the elongation range is 10%-40%. In other embodiments, the tenacity range is 3.0-4.0 grams/dtex and the elongation range is 80%-110%.
[0030] In further embodiments, the melt spun polymer is in the form of a draw textured yarn of a material selected from Nylon 6.6, Nylon 6, polyesters, polypropylenes, polyolefines, and poly(lactic acid). In some embodiments, the yarn is characterized by a tenacity range of 4.0-6.0 grams/dtex and an elongation range of 30%-50%. In some embodiments, the tenacity range is of 4.5-6.0 grams/dtex and the elongation range is of 35%-45%.
[0031] In other embodiments, the wet spun polymer is selected amongst poly(acrylonitrile), polyvinyl alcohol), viscose rayon, and regenerated cellulose.
[0032] In some embodiments, the polymeric fibers are microfibers of high fiber content (number of fibers in a volume unit) and high surface area, thus bringing about a high efficiency in endowing the surface with the desired property, e.g., biofouling protection. Inhomogeneous dispersion of the fibers within the protected structure walls that concentrates the fibers at the surface and maximizes the contact area between the fibers and the environment. The direct contact between the fibers at the surface of the structure, on one hand, and the environment, on the other, is necessary to reduce or minimize exposure of the surface to the damaging environment.
[0033] The environment to which the surface of the structure is exposed, and which is said of potentially having a deteriorating or damaging effect on the surface structure, is any environment containing at least one biological or chemical entity which has the potential of causing short or long-term damage to the structure. Such environments may be solids, liquids, gases or solutions which come into direct contact with the surface of the structure. The environment may be aqueous or non-aqueous and may contain a chemical or a biological material (microorganism) that can cause damage to the structure. In some embodiments, the environment is water which may be standing water (as in the case of water reservoirs) or which may flow on the surface or in contact with the surface of the structure (as a water flow inside a pipe).
[0034] Therefore, the polymeric fibers containing or being coated with reactive agents are selectively localized at the surfaces of the structure, protruding into the environment (water in case of anti-biofouling applications) and forming contact with the environment e.g., water, at the wall-environment interface; thus, for example in antifouling applications, preventing settling of microorganisms on the structure surface and thereby preventing eventual fouling of the surface.
[0035] In some embodiments, the volume fraction of fibers in the element at the surface of the structure is between 0.025% and 25%. In some embodiments, the volume fraction is at least about 0.1%. In some embodiments, the volume fraction is between about 0.1% and 10%. In other embodiments, the volume fraction is between about 0.2 and 1%, or between about 0.2 and 0.5%, or between 0.1 and 0.2%.
[0036] In some embodiments, the fiber content at the surface is in the range of 100 million and 100,000 million fibers per a cubic meter. In other embodiments, the range is of 1,000 million and 10,000 million fibers per a cubic meter.
[0037] In other embodiments, the fiber content at the surface is between about 150 and 1,000 million fibers per a cubic meter. In other embodiments, the fiber content is between 500 and 1,000 million fibers per cubic meter.
[0038] In further embodiments, the number of protruding fibers per a surface area unit of the structure is between 1 and 100 fibers in a square mm. In other embodiments, the number of protruding fibers per a surface area unit of the structure is between 1 and 10 fibers in a square mm.
[0039] The biological or chemical agent is selected to be capable of endowing the fibers and thus the structure surface with a biological or chemical resistance to at least one biological or chemical effect, which in the absence of such fibers would eventually bring about a short-term or long-term damage. In the context of the invention, the biological or chemical agent one or more such agents selected to modulate one or more property of the structure material or surface, namely to improve its resistance to a certain environmental condition. In some embodiments, the resistance to such a condition is selected from resistance to biofouling, retarding fire and preventing fire-induced damage, resistance to corrosion, resistance to oxidation, resistance to surface-penetration by external agents and chemicals that damage the matrix, such as sulfates, carbon dioxide, chlorides, phosphates etc. The agent may thus be a biological agent selected from a biocide, a bacteriocide, a quorum sensing antagonist that retards bacteria growth and others. Where the agent is a chemical agent, it is typically selected from metal microparticles, metal nanoparticles, metal oxides, metal salts, fire retarding agents, corrosion resistance compounds, pH modulators, and UV resistance compounds.
[0040] Non-limiting examples of such agents include metal salts such as silver, zinc and copper; metal oxides such as silver oxide, zinc oxide, and copper oxide; organic biocides such as phenolic based products, Microban products, triclosan, salts of imazalil, ortho phenyl phenol, zinc pyrithione, tolyl diiodomethyl sulfone, oxathiazine, azole, chlorothalonil, triazin diamine and others.
[0041] In some embodiments, the biological agent is a quorum sensing antagonist capable of disturbing biofilms formation or bacteria production sequence. In some cases, the fibers comprise biocides in an amount ranging from 0.01% and 20.0% wt. In other cases, the amount of the biocide in or on the polymeric fibers is between 0.1% and 5.0% wt.
[0042] In some cases, the amount of the quorum antagonist in the fibers is between 0.001% and 5.00% wt.
[0043] In some embodiments, the weight concentration of the biological or chemical agent in or on the surface of the polymeric fibers is between about 0.1-15%, or between 1 and 10%, or between 5 and 10%, or between 10 and 15%, or between 0.1 and 1%. In some embodiments, the concentration is between about 0.1 and 1%.
[0044] In further embodiments, the overall content of the biological agent in the matrix is between about 5-100 ppm.
[0045] In some embodiments, the biocide is in the form of nano-sized particles of metal salts or oxides. In some embodiments, the particles having a diameter of at most 500 nanometers.
[0046] In seine embodiments, where the structure of the invention is a water conveying element, the polymeric fibers are selected to be capable of interacting with microorganisms and prevent their growth, thereby protecting the surface of the structure from biofouling, microorganism-induced corrosion (e.g., in concrete structures), hydrogen sulfide formation (e.g., in sewage systems) and other deterioration effects.
[0047] The fibers containing or being coated with the biological or chemical agents protrude from the surface and remain continuously exposed to the environment, e.g., remain in continuous contact with microorganisms which may have a deterioration effect on the surface. This prevents settling and growth of bacteria and other microorganisms on the surfaces, eliminating colony-formations that eventually results in biofouling and other associated effects at the surface of the structure, e.g., walls of the water treating elements.
[0048] The polymeric fibers employed are engineered to react to environmental conditions and to regulate the rate of release of the biological or chemical agents that diffuse therefrom and interact with the microorganisms at the surface. In some embodiments, Nylon fibers of high content of carboxyl end-groups (e.g., more than 80 meq/Kg), such as Nylon 6.6 or Nylon 6 fibers, are employed. In such embodiments, hydrolysis of the fibers ensues as the pH of the environment to which the fibers are exposed, e.g., water, decreases due to the effect exerted by the present microorganisms.
[0049] Similarly, in other embodiments, polyvinyl alcohol fibers, engineered to dissolve as the time and/or temperature increase, can serve to kinetically release the biological or chemical agents into the water and to maintain constant concentration of biocides at the surface in order to prevent microorganism growth.
[0050] In another of its aspects, the present invention provides a process for manufacturing a structure according to the invention, the process comprising:
obtaining a mixture of a desired material (making up the bulk material of the structure, said desired material may be selected from a plaster material, a cementitious material, a mortar, concrete, a polymeric material, plastic, a fabric, a yarn, a carbonaceous material, a paper material and others) and a plurality of polymeric fibers containing or being coated with a biological or chemical agent; forming (e.g., by casting) a structure of said mixture; and treating at least a portion of the structure surface to expose the fibers' ends; to thereby obtain a structure having a plurality of polymeric fibers protruding from at least a portion of its surface, the fibers containing or being coated with at least one biological or chemical agent.
[0054] In another of its aspects, a structure devoid of polymeric fibers may be transformed into a structure according to the present invention by employing a process comprising:
obtaining a structure of a desired material, as above; coating at least a portion of the structure surface with a material comprising a plurality of polymeric fibers; and treating the coating layer to expose the fibers' ends; to thereby obtain a structure having a plurality of polymeric fibers protruding from at least a portion of its surface, the fibers containing or being coated with at least one biological or chemical agent.
[0058] The structure of the invention having polymeric fibers protruding from at least a portion of its surface may be utilized for a great variety of applications. In some embodiments, the structure is an element of a water system or sewage and is an element such as a pipe, a concrete pipe, a manhole, a pumping element, a desalination element, and others.
[0059] In such embodiments, the fibers are selected for ‘contact killing’ of microorganisms coming in contact with the inner surface of the element (pipe channel). The fibers containing or carrying the biological or chemical agents are dispersed within the bulk of the structure (element) during batching. The fibers are then exposed at the inner surfaces of the structure using several possible methods:
[0060] a. After casting the element a retarding agent is applied to the surface via brushing or sprinkling, in order to retard the concrete hydration at the surface. After a minimum consolidation time of the cast elements (6-12 hours), the surface unbound cementitious components are rinsed off by pressurized water, exposing the ends of the fibers that protrude through the wall surface, while their other ends are bound to the deeper cementitious layers that are not affected by the retarder. This results in a dense layer of free fibers at the surface of the element wall.
[0061] The fibers may be exposed (excavated) also via mechanical abrasion (sand papering) of the surfaces, exposing the fibers protruding through the surface.
[0062] In some embodiments, where hydrophobic fibers such as polypropylene are employed, migration to the surface of the wet concrete during casting, results in the formation of high fiber concentration at the wall interface.
[0063] b. The structure may be formed or casted and subsequently thereto its surface may be coated with a grout that contains the reactive fibers and which is capable of partial dissolution or crumbling to expose the fibers at the surface after application (coating). This enables coating of newly formed elements during production in a separate stage and protection of old systems by coating existing pipes and the inner surfaces of other elements. Thus, this process enables the application also to cementitious as well as non-cementitious, e.g., plastic elements.
[0064] The coating applied to the at least a portion of the surface can be of a single coating layer or of multi layers. In some embodiments, the application is of at least two layers, the first being a base layer containing an adhesive (e.g., acrylic or epoxy based) that binds the grout to the substrate wall and a further top layer containing the cement matrix and fibers. The cement matrix can contain soluble polymers that form internal void-networks, increasing the contact area of the fibers with the water.
[0065] In some embodiments, a single coating layer may suffice. In such cases, the grout is a one layer system containing an adhesive, fibers and a cement system.
[0066] After coating the surface of the element with the coating material, the fibers may then be exposed using any of the methods disclosed above, e.g., through mechanical sand papering that crumbles parts of the dry cementitious powder , or via dissolution of part of the matrix, leaving the fibers protruding at the surfaces.
[0067] In other embodiments, the structure is a yarn which may be utilized for filtration in candle filters and in other types of filters, and which protection against biofouling microorganisms is required. In such structures, the protecting fibers protrude through the surface of the yarns forming a high degree of hairiness that is reassuring the contact of the reactive fibers with the water at the surface of the filters. The degree of hairiness could be controlled by the yarn formation process:
[0068] a. Texturizing of the reactive yarns to a high degree of crimp levels.
[0069] b. Employing any bulking, like the Taslan yarn forming method to generate hairy yarns that are incorporated into a bundle of yarns in the filters, contributing protruding reactive fibers.
[0070] In further embodiments, the structure is a fabric containing polymeric fibers. Such fabrics may be used as spacers in membranes. The reactive fibers protrude through the fabric surface and form high contact with the environment (water) around the fabric. Similarly to the production of yams, the fabrics may be obtained via texturizing or via any of the bulk yam formation methods.
B. Protection Via Bulk Distribution of the Fibers in the Matrix
[0071] The chemical characteristics of short cut synthetic fibers that are used for dispersion in concrete and cementitious materials are modified in order to enable dissolution of the fibers at predetermined conditions of environment pH, temperature and time.
[0072] Controlled dissolution of the fibers permits the controlled release of their contents, and for affecting the structure and characteristics of the concrete after their dissolution.
[0073] Controlled dissolution of the fibers is achieved in condensation polymers that undergo hydrolysis under specific conditions:
[0074] Polyamides (Nylon 6, Nyon 6.6) undergo hydrolysis as the pH drops.
[0075] This is used for dissolving the fibers in concretes that are attacked by bacteria and microorganisms that produce strong acids and by chemicals that reduce the pH of the concrete and deteriorate it.
[0076] Fibers containing biocides and corrosion resisting chemicals are dispersed in the concrete and dissolve to release their biocides and chemicals contents as the activity of the bacteria and the corroding chemicals increases.
[0077] Polyamides of imbalanced end groups with high carboxyl contents (more than 80 meq/Kg) undergo rapid hydrolysis in boiling water. This is being used for dissolving the fibers at the concrete's steam environment during fire.
[0078] Similarly, poly (ethylene terphthalate) fibers undergo hydrolysis in steam at the high pH conditions of the concrete.
[0079] Polyvinyl alcohol/acetate co-polyenes dissolve in water at a controlled time and temperature kinetics. Fibers spun from the co-monomer composition that dissolves readily in boiling water are used to percolate the concrete and release the steam pressure in fire.
[0080] Further examples of the applications in fire resistance and chemical corrosion resistance are given below.
[0000] C. Methods of Incorporating the Chemical Agents into the Fibers
[0081] During Fiber Formation:
[0082] In melt spinning—master batch of the reactive metal salts/oxides is incorporated into the molten polymers during melt spinning of Nylon, polyethylene and polypropylene and other thermoplastic fibers at high processing temperatures of up to 300° C.
[0083] Standard master batching of the additives with the polymers is applied for spinning the polymers containing the additives.
[0084] Standard silver additives have been used in Nylon 6.6 fibers, following the recommended procedure of the manufacturer: (e.g: Milliken Corp. “Alphasan silver inorganic antimicrobial technology”).
[0085] In wet spinning—dispersing the bacteriocide in the dope (solution of polymer in the spinning solvent) and spinning through the spinneret into the coagulaton bath at relatively low temperatures (50-150° C.) enables incorporation of organic biocides of lower thermal stability.
[0086] Injecting dispersions of the agents in the solvent into the spinning line before the spinneret enables increasing the biocides concentration in the fibers to the levels beyond 10%.
[0087] After treatment: Impregnation of the fibers with the reactive agent, squeezing and drying to a predetermined dry pick up.
DETAILED DESCRIPTION OF EMBODIMENTS
[0088] 1. Protection Via Surface Interaction of the Fibers with the Environment
[0089] Various embodiments and aspects of the invention as delineated hereinabove and as claimed in the claims section below find support in the following description and non-limiting examples.
[0090] Chemical agents for killing, repulsing or inhibiting growth of microorganisms in water are incorporated into the polymeric fibers during production by, e.g., fiber-spinning, or as surface coating on the fibers. The treated fibers are incorporated into structures such as concrete structures and provide protection against microorganisms that cause biofouling, corrosion, hydrogen sulfide formation, etc, via interaction of the chemical agent in the fibers with the microorganisms. Such chemical agents may be metal-ion bearing compounds, such as metallic silver, nano silver ions dispersion, zinc oxide, copper oxides and copper salts, organic bacteriocides, such as triclosan, imzazlil salts, o-phenyl phenol and zinc pyrithione, and organic quorum sensing antagonists which retard the activity of receptors in the microorganisms. The chemical agent is typically loaded into the fibers at a concentration of between about 0.1% and 15% wt.
[0091] The herein disclosed invention is based on the usage of fine diameter microfibers, having a large surface area, dispersed inhomogenously within the structure element in order to obtain a dense fiber-loaded surface of the protected element. The concentration of the fibers at the surface of the protected element is usually between about 0.015% vol and about 0.5% vol, thereby obtaining a fiber concentration of between about 150 million and about 1,000 million fibers per cubic meter. This is equivalent to about 1 and about 20 fibers per millimeter square. A direct contact between the fibers at the surface of the element and the environment, e.g., water, is necessary in order to eliminate microorganism accumulation upon settling on the element walls. In order to obtain a direct contact between the fibers and the microorganisms, the surface of the protected element is treated to expose the fibers, causing them to protrude into the water and to form direct contact with the microorganisms at the element/water interfaces. The direct contact between the chemical-loaded fibers and the microorganisms causes prevention of the settlement and growth of bacteria and other microorganisms on the surface of the protected element, eliminating biofouling colonies formation and other associated effects, such as corrosion. By careful selection of the material out of which the fiber is made, the fibers can be engineered to react to environmental conditions and to regulate the rate of release of the biological or chemical agents contained therein. Such materials may be Nylon 6.6 or Nylon 6 polymers of balanced carboxyl end-groups, i.e., 70 meq/kg or non-balanced carboxyl end-groups, i.e., more than 80 meq/kg, which undergo enhanced hydrolysis as the pH of the water decreases due to the effect exerted by the bacteria-related processes. Another material may be polyvinyl alcohol, engineered to decompose with a time and/or temperature increase, which can be used to kinetically control the release of the chemical agent from the fiber into the water to maintain constant concentration of chemical agent at the element/water interface.
[0092] The polymeric fibers are produced of polymers, such as Nylon 6.6, Nylon 6, poly(ethylene terephthlate), polyacrylonitrile, polyvinyl alcohol, polypropylene and polyethylene. The fibers are between about 1 mm and about 50 mm in length, and between about 1 and 40 micrometers in diameter, characterized by a 0.01-6.0 dtex, wherein the dtex measuring unit is defined as the mass of the fiber in grams of 10,000 m. In case the fibers are also used as a mechanical reinforcement of the concrete, covering the primary and the secondary ranges of reinforcement, the fibers should have a tenacity of between about 2.5 and about 9.0 grams per dtex and elongation of between about 5% and about 130%, that covers the types of Partially Oriented Yarns (2 nd reinforcement) and Fully Drawn yarns (Primary reinforcement).
EXAMPLE 1
[0093] Fibers:
[0000] Nylon 6.6 partially oriented yarns containing nano silver
Tenacity—3.40 gpd, Elongation—75%
Thickness—50 Dtex, Count—40 filaments, dtex per filament—1.25, diameter—11 micrometers,
Cut length—6 mm.
[0094] Fiber Spinning:
[0000] The process comprising extruding at a given extrusion rate a plurality of streams of the molten polymer (300° C.) through spinneret capillaries into a quench zone, quenching the molten streams into filaments, withdrawing the filaments from the quench zone and converging the filaments into a yarn that is wound on a bobbin at the spinning speed.
Spinning speed is 4,000 m/ min, Polymer Relative Viscosity is 40.
[0095] Adding the biocide:
[0000] Nano silver commercially available in the form of masterbatch of Nylon 6.6 containing the additive at a high concentration (15-25%): Alphasan silver inorganic anti bacterial agent, from Milliken Corp.
The masterbatch was metered into the extruder hopper separately, mixing with the regular Nylon chips feeding stream.
Silver content in the fibers: 0.3%.
[0096] Grout:
[0000] Cementitious grout of high cohesion with the concrete and plastic surfaces contained acrylic adhesive (one part) and cement powder (2.5 parts) and 0.2% by weigh of the above fibers.
Strips of grouts (5 mm thick) containing fibers and control grouts without fibers (reference) were prepared and subjected to biocide attack.
The fibers containing grouts were abraded at the surface to expose the fibers to the environment.
[0097] Test 1:
[0000] The strips were immersed in beakers with water containing vegetation for two weeks.
The reference strip without fibers developed heavy bio-organisms on the surface and in the water, while the water in the fibers containing strip remained clear and the strip stayed white after the two weeks.
[0098] Test 2:
[0000] Fibers: same as in Test 1.
Grout: contained acrylic adhesive (one part) and cement powder (2.5 parts) and 1% by weight of the above fibers. Grouts with and without fibers were prepared for a comparative test.
Application of the grouts: The grout coated the internal wall of a PVC pipe (5 cm diameter) using an adhesive layer to stick it to the wall. A 5 mm thick layer was applied manually and brushed after drying to excavate the fibers at the surface. Samples of pipes coated with the fibers containing cement, and with the reference grouts were prepared.
[0099] Short segments of the pipes were connected to the treated waste water line of a major waste treatment plant (“Shafdan”) and were exposed to the treated waste water environment during two summer months (August-September). After exposure, the pipes were retrieved for inspection. The pipes with the fibers containing grouts were not affected and remained white, while the pipes with the control grout were heavily contaminated with a biofouling layer.
2. Protection Via Bulk Distribution of the Fibers in the Matrix
Synthetic Fibers for Increasing Fire Resistance of Concrete Structures
[0100] Condensation and addition polymers like Nylons, polyesters and polyvinyl alcohols that undergo hydrolysis and dissolution in water at high temperatures, are modified chemically, mechanically and geometrically in order to enhance their tendency for hydrolysis and dissolution in boiling water (100° C.) and also to enhance their capacity to form networks of inter-connected channels in the concretes (percolate). This facilitates the earlier disintegration and dissolution of the fibers by the concrete's steam in the event of fire, to form hollow channels connecting the cement/aggregates interconnect and free interfacial voids into an open network throughout the concrete volume, for early release of the steam generated in the concrete during fire.
[0101] Early evacuation of the water vapor pressure built up is also facilitated and release of the steam-pore pressure in the burning concrete that causes bursts, surface flaking and explosive spalling of the concrete in the event of fire as the concrete temperature rises.
[0102] The earlier evacuation of the steam in the event of fire is critical for the effectiveness of the protection of the concrete itself against bursting. The steam evacuated concrete is fire resistant, and serves as a protective layer for the concrete steel reinforcement; such fibers are therefore a very effective mean for protecting the steel reinforcement against fire in concrete structures.
[0103] The early fiber disintegration and concrete percolation is needed especially in the dense impermeable high performance concretes, where the pressure build-up in the event of fire is most rapid and catastrophic. The objective is thus to promote the pressure release at temperatures lower than 200° C. (that is the liquefying temperature of standard polypropylene reinforcing fibers that degrade at 250° C.), preferentially at the water boiling temperature.
[0104] Fibers that disintegrate in boiling water via hydrolysis (modified condensation polymers such as Nylon and polyester of higher hydrolysis rates) or fibers that dissolve in the boiling water (such as polyvinyl alcohol copolymers with polyvinyl acetate) are chemically suitable.
[0105] Fiber morphology of lower degree of crystallinity and orientation that increases the water permeability and degradation/dissolution rates may be utilized. For this reason, the usage of lower orientation and lower strength fibers with a high degree of shrinkage at the boiling temperature, manufactured at lower than standard draw ratios, is recommended (e.g., partially oriented yarns, un-drawn yarns, lower draw ratio yarns, etc).
[0106] In order to readily percolate the concrete matrix via the formation of continuous network of interconnected channels upon the disintegration of the fibers, that is capable of evacuation of the vapor pore pressure in the concrete, fibers geometry in terms of diameter and length should be optimized to enable most efficient pressure release at the lowest dosage of fibers in the concrete (e.g., short cut 6-12 mm long micro fibers of 10-19 micron diameter, and/or longer macro fibers of 19-40 mm in length and 100-500 microns in diameter).
[0107] Examples of suitable polymers for the earlier degradation fibers formation:
[0108] 1. Nylon 6.6 and Nylon 6 modified chemically to have higher than the standard balanced carboxyl end groups (more than 80 meq/Kg) that catalyzes the hydrolysis by steam (low pH triggered hydrolysis).
[0109] 2. Polyester fibers selected to be susceptible to water boiling temperature hydrolysis at the concrete high pH, having the right molecular weight and morphology for rapid hydrolysis at the boiling point of the water in the concrete:
[0110] Undrawn, high speed spun (POY) fibers of standard to lower molecular weight (Mn=10,000-30,000), birefringence values within the range of 0.001-0.060, density values within the range 1.33-139 gram/cubic centimeter, tenacity within the range 2.5-6.0 gram per denier and elongation range of 60-200%.
[0111] As the diffusivity rate of the hydroxyl in the concrete into the fibers controls the rate of hydrolysis, the lowest degree of crystallinity and the finer diameter of fibers bring about faster hydrolysis rates. Accordingly, microfibers of 1.0-3.0 denier per filament thickness and of densities within the above specified range and degrees of crystallinity measured by WAXS and defined by the Index of crystallinity to be no more than 0.40 are most suitable.
[0112] 3. Polyvinyl alcohol/acetate copolymers obtained via incomplete acetate conversion to alcohol during the polyvinyl alcohol polymer formation, dissolve in water due to crystalline imperfections.
[0113] Fibers spun from the co-monomer composition containing the right residual content of acetyl groups within the vinyl acetate range of 0.1-5.0 mol %, dissolve at or below the boiling point of the water in the concrete (e.g., Kuralon fibers type WN7, WN8, WQ9, that dissolve in water at 70,80,95° C., respectively).
[0114] The mechanical properties and morphology of the fibers are adjusted for maximum effectiveness in terms of the concrete reinforcement demands; to contribute secondary and primary concrete reinforcement in addition to the fire resistance capacity.
[0115] The geometry (diameters and lengths) of the fibers are optimized for maximum rates of hydrolysis and dissolution of the fibers and for the optimal network of channel formation, for release of the steam (e.g., microfibers of 10-20 micrometers in diameter and 6-12 mm in length and/or macrofibers of 30-1,000 microns in diameter and 20-100 mm in length).
[0116] The effectiveness of the fibers in fire resistance enables the usage of much lower dosages of fibers relative to the standard fibers that are being used.
EXAMPLE 2
[0117] Fibers:
[0118] Poly (ethylene terphthalate) Partially Oriented Yarn fibers
[0119] Thickness: 3.00 Dtex per fiber.
[0120] Tenacity: 3.00 grams/dtex, Elongation: 85%
[0121] Spinning speed: 3,800 m/min, Intrinsic viscosity: 0.68
[0122] Spinning temperature: 295° C.
[0123] Cut length: 6 mm
[0124] Test 1:
[0125] The fibers are dispersed in the concrete following a standard mixing procedure of synthetic fibers with concrete for secondary reinforcement (70 revolutions at high speed). Concrete mix design—Cement: 400 Kg, Sand: 600 Kg, fine aggregates: 300 Kg, coarse aggregates: 800 Kg, water: 200 Kg.
[0126] Fiber content in the concrete: 2,000 grams/cubic meter
[0127] Testing of passive fire protection for concrete is performed showing very good fire resistance, including temperature/time profiles, spalling, cracking and surface observations.
EXAMPLE 3
[0128] Fibers:
[0129] Nylon 6.6 Partially Oriented Yarn fibers
[0130] Relative viscosity: 40, Carboxyl end groups: 80 meq./KG
[0131] Fiber properties—Thickness: 1.5 Dtex per fiber. Tenacity: 3.4 grams/dtex,
[0132] Elongation: 75%
[0133] Spinning speed: 4,000 m/min, p Spinning temperature: 295° C.
[0134] Cut length: 6 mm
[0135] Test:
[0136] The fibers are dispersed in the concrete following standard mixing procedure of synthetic fibers with concrete for secondary reinforcement (70 revolutions at high speed). Concrete mix design—Cement: 400 Kg, Sand: 600 Kg, fine aggregates: 300 Kg, coarse aggregates: 800 Kg water: 200 Kg.
[0137] Fiber content in the concrete: 2,000 grams/cubic meter
[0138] Testing of passive fire protection for concrete is performed showing very good fire resistance, including temperature/time profiles, spalling, cracking and surface inspection.
EXAMPLE 4
[0139] Fibers:
[0140] Poly (vinyl alcohol coacetate) fully drawn Yarn fibers
[0141] Thickness: 1.25 Dtex per fiber.
[0142] Tenacity: 9.00 grams/dtex, Elongation: 5%
[0143] Water dissolvable at 70° C.
[0144] Cut length: 6 mm
[0145] Test:
[0146] The fibers are dispersed in the concrete following standard mixing procedure of synthetic fibers with concrete for secondary reinforcement (70 revolutions at high speed). Concrete mix design—Cement: 400 Kg, Sand: 600 Kg, fine aggregates: 300 Kg, coarse aggregates: 800 Kg water: 200 Kg.
[0147] Fiber content in the concrete: 2,000 grams/cubic meter
[0148] Testing of passive fire protection for concrete is performed showing very good fire resistance, including temperature/time profiles, spalling, cracking and surface inspection.
3. Chemical Corrosion Resisting Fibers
[0149] Synthetic fibers containing corrosion resisting chemicals are dispersed in the concrete in order to release the chemicals at the steel reinforcement corrosion spots within the concrete, thereby terminating the corrosion processes and increasing the life span of the steel and the reinforced elements.
[0150] Various release mechanisms are proposed:
[0151] In Nylon encapsulated fibers, controlled release via response of the. Nylon to pH is obtained using pH degradation sensitive Nylon polymers that degrade faster and release more protecting chemicals as the pH becomes more acidic due to carbon dioxide, sulfates and other corroding chemicals ingestion into the concretes.
[0152] In polyvinyl alcohol copolymers, with vinyl acetate made fibers that dissolve in water at ambient temperatures, following predetermined rates of dissolution, the kinetics of dissolution and chemicals release to the concrete are controlled.
[0153] Standard corrosion resistance chemicals such as nitrites, molybdenates, phosphonates, morpholines, hydrazines may be used as corrosion resisting chemicals.
[0154] Incorporation of chemicals into the fibers:
[0155] In melt spinning: via inclusion of the chemicals in the polymer during polymerization, and/or blending master batches containing the chemicals with the regular polymer chips in the extruder prior to spinning.
[0156] In wet spinning: via mixing of suspensions of the chemicals with the polymer in the dope (solution of polymer in the solvent) prior to wet spinning, or injection of suspensions of the chemicals in the spinning solvent to the spinning line prior to the spinneret.
[0157] Contents of the chemicals in the fibers within the range of 0.1%-10% are obtainable.
[0158] High strength and rigidity short cut (3-12 mm) fibers in the mortar surrounding the steel reinforcement form barrier that maintains higher osmotic pressures around the reinforcing bars, making them impermeable to the corroding carbonates and other chemicals due to the higher chemical potential within the corroded iron oxide swollen gels that prevent further diffusion into the steel protected zone. This protects the steel reinforcement against corroding carbonates, chlorides and sulfates.
[0159] High elongation fibers for increasing concrete flexibility and shear strainability:
[0160] Nylon or poly propylene or poly vinyl alcohol fibers of low degrees of orientation and high extension to break (e.g., elongation greater than 500%, tenacity lower than 3.0 grams per denier), obtained via very low draw ratios during their formation processes, characterized by low birefringence and other orientation indications (i.e., birefringence in Nylon 6.6 fibers lower than 0.040), will be added to the cementitious mixture in order to reduce the composite's modulus and increase the extension and bending breaking strains of the system to values that upgrade specific properties of the reinforced products to reach high performance demands at relatively low dosages of fibers, replacing high cost rubbers and polymeric resins that are usually added to the cementitious system for equivalent effects. The fibers durability at high temperatures and their environmental stability, imply clear advantage over the standard additives. | The technology being at the core of the present invention relates to the use of novel fibers in the construction of reinforced elements and methods for their manufacture. The fibers effectively upgrade the inherent properties of the elements, as specified herein. |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to ballistic-resistant articles and process for making them.
[0002] Ballistic-resistant articles, such as bulletproof vests, helmets, structural members of helicopters and other military equipment, vehicle panels, briefcases, raincoats, aircraft luggage containers, military aircraft seats, gas turbine engine containment rings, military troop shelters, boot soles and other personal protective items, overwrapping or overbraiding of telephone electrical lines and aerospace wire and cable, and military electronic shelters containing high strength fibers, are known. Fibers conventionally used include aramids, such as poly(phenylenediamine terephthalamide), nylon fibers, glass fibers, graphite fibers and the like. Other suitable fibers as described in U.S. Pat. Nos. 4,623,574, 4,457,985 and 4,650,710 include ultra high molecular weight (UHMW) polyethylene, polypropylene or polyvinyl alcohol fibers.
[0003] Ballistic-resistant articles made of these known fibers are generally heavy and bulky and are, therefore, uncomfortable to wear. It would be desirable to provide ballistic-resistant articles which are lighter, more comfortable to wear and exhibit better ballistic-resistant properties than existing ballistic-resistant articles.
SUMMARY OF THE INVENTION
[0004] One aspect of the present invention is a ballistic-resistant article comprising a plurality of polybenzoxazole (PBO) or polybenzothiazole (PBT) polymer fibers.
[0005] A second aspect of the present invention is a laminate comprising multiple plies of PBO or PBT fabric and a matrix resin.
[0006] The ballistic-resistant articles of the present invention provide significantly improved ballistic protection than current materials of equal weight.
DETAILED DESCRIPTION OF THE INVENTION
[0007] The present invention uses a plurality of fibers of polybenzoxazole (PBO) or polybenzothiazole (PBT) polymers or copolymers thereof.
[0008] PBO, PBT and random, sequential and block copolymers of PBO and PBT are described in references such as Wolfe et al., Liquid Crystalline Polymer Compositions, Process and Products, U.S. Pat. No. 4,703,103 (Oct. 27, 1987); Wolfe et al., Liquid Crystalline Polymer Compositions, Process and Products, U.S. Pat. No. 4,533,692 (Aug. 6, 1985); Wolfe et al., Liquid Crystalline Poly (2,6- Benzothiazole ) Compositions, Process and Products, U.S. Pat. No. 4,533,724 (Aug. 6, 1985); Wolfe, Liquid Crystalline Polymer Compositions, Process and Products, U.S. Pat. No. 4,533,693 (Aug. 6, 1985); Evers, Thermoxadatively Stable Articulated p - Benzobisoxazole and p - Benzobisthiazole Polymers, U.S. Pat. No. 4,359,567 (Nov. 16, 1982); Tsai et al., Method for Making Heterocyclic Block Copolymer, U.S. Pat. No. 4,578,432 (Mar. 25, 1986); 11 Ency. Poly. Sci. & Eng., Polybenzothiazoles and Polybenzoxazoles, 601 (J. Wiley & Sons 1988) and W. W. Adams et al., The Materials Science and Engineering of Rigid - Rod Polymers (Materials Research Society 1989), which are incorporated herein by reference.
[0009] The PBO or PBT polymer may contain AB-mer units, as represented in Formula 1(a), and/or AA/BB-mer units, as represented in Formula 1(b)
wherein:
[0010] Each Ar represents an aromatic group. The aromatic group may be heterocyclic, such as a pyridinylene group, but it is preferably carbocyclic. The aromatic group may be a fused or unfused polycyclic system, but is preferably a single six-membered ring. Size is not critical, but the aromatic group preferably contains no more than about 18 carbon atoms, more preferably no more than about 12 carbon atoms and most preferably no more than about 6 carbon atoms. Examples of suitable aromatic groups include phenylene moieties, tolylene moieties, biphenylene moieties and bis-phenylene ether moieties. Ar 1 in AA/BB-mer units is preferably a 1,2,4,5-phenylene moiety or an analog thereof. Ar in AB-mer units is preferably a 1,3,4-phenylene moiety or an analog thereof.
[0011] Each Z is independently an oxygen or a sulfur atom.
[0012] Each DM is independently a bond or a divalent organic moiety that does not interfere with the synthesis, fabrication or use of the polymer. The divalent organic moiety may contain an aliphatic group, which preferably has no more than about 12 carbon atoms, but the divalent organic moiety is preferably an aromatic group (Ar) as previously described. It is most preferably a 1,4-phenylene moiety or an analog thereof.
[0013] The nitrogen atom and the Z moiety in each azole ring are bonded to adjacent carbon atoms in the aromatic group, such that a five-membered azole ring fused with the aromatic group is formed.
[0014] The azole rings in AA/BB-mer units may be in cis- or trans- position with respect to each other, as illustrated in 11 Ency. Poly. Sci. & Eng., supra, at 602, which is incorporated herein by reference.
[0015] The polymer preferably consists essentially of either AB-PBZ mer units or AA/BB-PBZ mer units, and more preferably consists essentially of AA/BB-PBZ mer units. The polybenzazole polymer may be rigid rod, semi-rigid rod or flexible coil. It is preferably rigid rod in the case of an AA/BB-PBZ polymer or semi-rigid in the case of an AB-PBZ polymer. Azole rings within the polymer are preferably oxazole rings (Z=0). Preferred mer units are illustrated in Formulae 2 (a)-(g). The polymer more preferably consists essentially of mer units selected from those illustrated in 2(a)-(g), and most preferably consists essentially of a number of identical units selected from those illustrated in 2(a)-(c).
[0016] Each polymer preferably contains on average at least about 25 mer units, more preferably at least about 50 mer units and most preferably at least about 100 mer units. The intrinsic viscosity of rigid AA/BB-PBZ polymers in methanesulfonic acid at 25° C. is preferably 15 dL/g and most preferably at least about 20 dL/g. For some purposes, an intrinsic viscosity of at least about 25 dL/g or 30 dL/g may be best. Intrinsic viscosity of 60 dL/g or higher is possible, but the intrinsic viscosity is preferably no more than about 40 dL/g. The intrinsic viscosity of semi-rigid AB-PBZ polymers is preferably at least about 5 dL/g, more preferably at least about 10 dL/g and most preferably at least about 15 dL/g.
[0017] The polymer or copolymer is dissolved in a solvent to form a solution or dope. Some polybenzoxazole and polybenzothiazole polymers are soluble in cresol, but the solvent is preferably an acid capable of dissolving the polymer. The acid is preferably non-oxiding. Examples of suitable acids include polyphosphoric acid, methanesulfonic acid and sulfuric acid and mixtures of those acids. The acid is preferably polyphosphoric acid and/or methanesulfonic acid, and is more preferably polyphosphoric acid.
[0018] The dope should contain a high enough concentration of polymer for the polymer to coagulate to form a solid article. When the polymer is rigid or semi-rigid, then the concentration of polymer in the dope is preferably high enough to provide a liquid crystalline dope. The concentration of the polymer is preferably at least about 7 weight percent, more preferably at least about 10 weight percent and most preferably at least about 14 weight percent. The maximum concentration is limited primarily by practical factors, such as polymer solubility and dope viscosity. The concentration of polymer is seldom more than 30 weight percent, and usually no more than about 20 weight percent.
[0019] Suitable polymers or copolymers and dopes can be synthesized by known procedures, such as those described in Wolfe et al., U.S. Pat. No. 4,533,693 (Aug. 6, 1985); Sybert et al., U.S. Pat. No. 4,772,678 (Sep. 20, 1988); Harris, U.S. Pat. No. 4,847,350 (Jul. 11, 1989); and Ledbetter et al., “An Integrated Laboratory Process for Preparing Rigid Rod Fibers from the Monomers,” The Materials Science and Engineering of Rigid - Rod Polymers at 253-64 (Materials Res. Soc. 1989), which are incorporated herein by reference. In summary, suitable monomers (AA-monomers and BB-monomers or AB-monomers) are reacted in a solution of nonoxidizing and dehydrating acid under nonoxidizing atmosphere with vigorous mixing and high shear at a temperature that is increased in step-wise or ramped fashion from no more than about 120° C. to at least about 190° C. Examples of suitable AA-monomers include terephthalic acid and analogs thereof. Examples of suitable BB-monomers include 4,6-diaminoresoreinol, 2,5-diaminohydroquinone, 2,5-diamino-1,4-dithiobenzene and analogs thereof, typically stored as acid salts. Examples of suitable AB-monomers include 3-amino-4-hydroxybenzoic acid, 3-hydroxy-4-aminobenzoic acid, 3-amino-4-thiobenzoic acid, 3-thio-4-aminobenzoic acid and analogs thereof, typically stored as acid salts.
[0020] The dope is spun into high tensile strength fibers by known dry jet-wet spin techniques in which the dope is drawn through a spinneret into a coagulation bath. Fiber spinning and coagulation techniques are described in greater detail in Tan, U.S. Pat. No. 4,263,245 (Apr. 21, 1981); Wolfe et al., U.S. Pat. No. 4,533,693 (Aug. 6, 1985); and Adams et al., The Materials Science and Engineering of Rigid Rod Polymers, 247-49 and 259-60 (Materials Research Society 1989), which are incorporated herein by reference. Each fiber preferably has an average diameter of no more than about 50 μm and more preferably no more than about 25 μm. Minimum fiber diameter is limited by practical ability to spin. Average fiber diameters are seldom less than about 1 μm and usually at least about 7 μm. Smaller denier filaments ordinarily provide better dexterity, but cost more. The average tensile strength of the fiber is preferably at least about 1 GPa, more preferably at least about 1.75 GPa, more highly preferably at least about 2.75 GPa, and most preferably at least about 4.10 GPa.
[0021] The fibers may be heat-treated for added stiffness and for improving the properties of composites made therefrom. However, for certain applications, such as soft armor where greater stiffness is not usually required, the fibers are preferably not heat-treated.
[0022] The fibers may be grouped together to form a twisted or untwisted yarn or may be used as reinforcements for a random fiber composite.
[0023] Yarns may either be from staple or from continuous filaments. For a staple-based yarn, the fiber is cut or stretch-broken into short segments, such as about 1 inch to 12 inches in length. The short segments are spun according to ordinary yarn spinning procedures to obtain a yarn suitable for further processing. For a continuous filament-based yarn, a number of continuous filaments are held together by known means, such as twisting, entanglement or application of a finish or sizing agent. The twist for a twisted yarn can be between 2 and 20 turns per inch, depending primarily on the diameter of the yarn. Preferably, the continuous filaments are held together without twisting by lightly sizing them.
[0024] The optimum denier of the yarn varies depending upon the desired use and price of the fabric. For most purposes, the yarn is preferably at least about 50 denier, more preferably at least about 200 denier and most preferably at least about 500 denier. For most purposes, the yarn is preferably at most about 2000 denier, more preferably at most about 1500 denier and most preferably no more than about 1000 denier. For example, the preferred range of denier for soft armor applications is from 150 to 500 denier and the most preferred range is from 150-300 denier. The same denier yarns are also suitable for hard armor applications but higher denier yarns in the range of 500 to 1500 denier are preferred for economic reasons.
[0025] The yarn is preferably lubricated with an oil and an antistatic agent for further processing into a fabric. Advantageously, before the fabric is used for a ballistic application, the lubricant is scoured off to improve ballistic performance and also to improve adhesion of the yarn or fabric to the matrix of a composite hard armor. In other applications, a specific lubricant, for example, silicone, may be specifically added to provide a weak interaction with the matrix material in a hard armor. Examples of such applications include light weight riot shields, as well as gun turret armor for battle ship applications.
[0026] The yarn may be made into a fabric or article of clothing by known methods, such as knitting, weaving, braiding or forming into non-woven fabric. For instance, the yarn may be knitted on conventional knitting equipment useful for knitting other high-strength fibers, such as aramid fibers. Knitting techniques are well-known in the art and are described, for example, in Byrnes, U.S. Pat. No. 3,883,898 (May 20, 1975) and/or Byrnes, U.S. Pat. No. 3,953,893 (May 4, 1976). The yarns may be woven on any type of looms such as, for example, the rapier, shuttleless, shuttle, needle, air jet and water jet looms. Yarn that is woven into a plain piece of fabric may be cut and sewn to make garments according to known procedures. The polybenzazole fiber yarn may be too cut-resistant for cutting tools which are standard on commercial equipment. It may be necessary to improve the cutting equipment or cut by hand.
[0027] The fabric may be used alone or may be embedded in a matrix to form a rigid panel. The fabric may also be interlayered with an isotropic, oriented liquid crystalline PBO or PBT film, or layered in combination with p-aramid, UHMW polyethylene or glass fibers.
[0028] Suitable matrix materials include, but are not limited to, thermoplastic polymers such as polyethylene, polypropylene, nylon, polyimide, polyethyleneimine (PEI), polyetherether ketone (PEEK), polyether sulfone (PES), polyearbonate, polyethylene terephthalate (PET); thermosetting polymers such as vinyl ester, vinyl butyral, epoxy resin, PBO, PBT, polyurethanes, cyanate esters, phenolics and silicones; and elastomers such as polybutadiene, polyisoprene, natural rubber, ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, polysulfide polymers, polyurethane elastomers, chlorsulfonated polyethylene, polychloroprene, plasticized polyvinylchloride using dioctyl phthalate or other plasticizers well known in the art, butadiene acrylonitrile elastomers, poly(isobutylene-co-isoprene), polyacrylates, polyesters, polyethers, fluoroelastomers, silicone elastomers, and thermoplastic elastomers, copolymers of ethylene.
[0029] The PBO fibers may be made into random fiber composites by cutting them into short lengths, such as, for example, from about 1 to about 12 inches, depending on specific end use and then orienting or randomly laying the cut fibers in a web to produce a felt-like material. A process for preparing fiber composites is described in U.S. Pat. No. 4,457,985, which is incorporated herein by reference.
[0030] The following U.S. patents, which are incorporated herein by reference, describe garments and/or fabrics containing commingled or composite fibers and/or two types of fibers woven together: Byrnes, U.S. Pat. No. 4,004,295 (Jan. 25, 1977); Byrnes et al., U.S. Pat. No. 4,384,449 (May 24, 1983); Bettcher, U.S. Pat. No. 4,470,251 (Sep. 11, 1984); Kolmes, U.S. Pat. No. 4,777,789 (Oct. 18, 1988); Kolmes, U.S. Pat. No. 4,838,017 (Jun. 13, 1989); Giesick, U.S. Pat. No. 4,856,110 (Aug. 15, 1989); Robins, U.S. Pat. No. 4,912,781 (Apr. 3, 1990); Warner, U.S. Pat. No. 4,918,912 (Apr. 24, 1990) and Kolmes, U.S. Pat. No. 4,936,085 (Jun. 26, 1990), which are incorporated herein by reference.
ILLUSTRATIVE EXAMPLES
[0031] The present invention is illustrated more fully by the following Examples. The Examples are for illustrative purposes only, and should not be taken as limiting the scope of either the Specification or the Claims. Unless stated otherwise, all parts and percentages are by weight.
Example 1
[0000] A. Preparation of Ballistic-Resistant Fabric
[0032] A plurality of fibers are spun by conventional means from a dope containing about 10 to about 20 weight percent rigid rod cis-polybenzoxazole polymer in polyphosphoric acid. The polymer has an intrinsic viscosity of between about 25 dL/g and about 40 dL/g as measured in methanesulfonic acid at about 30° C. The fibers are obtained from several runs and have the following range of properties: 14-20 dpf (denier per filament), 450 to 600 Ksi tensile strength, 18 to 25 Msi tensile modulus, and 1.5 to 2.5% elongation to break.
[0033] The fibers are formed into a continuous filament yarn having an average of about 450 to about 750 denier. Light weight knitting oil and an antistatic agent are applied to the tow as a lubricant. The yarn is twisted with 1.5 turns per inch on a Leesona ring twister having 5-inch rings.
[0034] The continuous filament yarn is woven into a fabric on a standard Rapier loom with a construction of 24×24 ends and picks in the warp and weft directions to obtain a fabric of 4 oz./sq. yard.
[0000] B. Ballistic Testing
[0035] The fabric prepared in Part A is cut into 8 inch squares. A hard armor test panel consisting of 8 of these 8 inch squares is constructed by placing a 4 mil thick film of low density polyethylene between each layer of fabric and compression molding these together under a pressure of 1000 psi and a temperature of 130° C. to form a plaque approximately 1.0 millimeter thick.
[0036] The test panel is securely clamped inside a wooden box frame backed by several layers of wood as a safety catch for any fragments which pass through the test panel. A piece of 1 inch glass fiber insulation batting is placed in front of the panel to deflect any rebounding projectiles. The panel is then shot with a 0.22 caliber revolver. The panel is shot at two locations, one in the center and one approximately 2 inches from a corner of the panel. In both cases, the slugs did not perforate the test panel.
Comparative Example
[0037] A test plaque is prepared as in the above example except that the fabric is prepared from commercial grade Spectral 1000 high performance UHMW polyethylene fiber produced by Allied-Signal Corporation. The fabric is thicker than the fabric used in Example 1, having been made from higher denier yarn, resulting in a thicker test plaque. This fabric represents the best state of the art ballistic material for use in hard armor devices such as helmets. When shot in a similar way to that described in Example 1, the two 0.22 caliber slugs perforated the plaque. | A bullet proof vest which is resistant to penetration by a 0.22 caliber projectile and includes a fabric or clothing made of polybenzoxazole polymer fibers. The vest is lighter, more comfortable to wear and exhibits better ballistic-resistant properties than traditional ballistic-resistant vests of equal weight. |
FIELD
[0001] The present disclosure relates generally to a vehicle parking brake or lock system and more particularly to a method of operating a park lock mechanism.
BACKGROUND
[0002] Vehicles transmissions have a park setting or gear in which the transmission may be locked and the vehicle turned off. When a vehicle is parked on a hill or other grade, gravitational forces on the vehicle provide a load on the vehicle park lock system. With such a load on the park lock system, disengagement of the park lock system to permit the transmission to be shifted out of park may be difficult or noisy or have a harsh movement.
SUMMARY
[0003] A method of operating a park lock mechanism in a vehicle includes determining a force acting on a vehicle park lock mechanism when the vehicle is in park, and providing an offsetting force to counteract the force on the park lock mechanism before the vehicle is shifted out of park. In doing so, harshness and noise that may be associated with shifting a vehicle out of park, especially when the vehicle is parked on an incline, can be reduced or eliminated.
[0004] In at least one implementation, a method of providing an offsetting force to a park lock system in a vehicle includes providing an offsetting force on a transmission output shaft in a direction opposite to the force on the transmission output shaft due to the force of gravity on the vehicle. The offsetting force, in at least one example, can be applied without first determining the magnitude of the force needed, and the offsetting force can be applied until the net force on the park lock mechanism, or on the output shaft, is below a threshold.
[0005] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings provided hereinafter. It should be understood that the summary and detailed description, including the disclosed embodiments and drawings, are merely exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the invention, its application or use. Thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a side view of one example of a park lock system in its disengaged or unlocked position where a park lock mechanism is not engaged with a park gear of a vehicle transmission;
[0007] FIG. 2 is a side view like FIG. 1 showing the park lock system in its engaged or locked position; and
[0008] FIG. 3 is a flow chart showing steps of a representative method for reducing the force on the park lock mechanism before the vehicle is shifted out of park.
DETAILED DESCRIPTION
[0009] Referring in more detail to the drawings, FIGS. 1 and 2 illustrate a park lock system 10 for a vehicle. The park lock system 10 includes a lock mechanism 12 that engages a park gear 14 of the vehicle transmission to hold or lock the vehicle transmission in park. The lock mechanism 12 is removed or disengaged from the park gear 14 to permit the vehicle transmission to be shifted out of park and into another gear (e.g. reverse, neutral or a forward drive gear).
[0010] In more detail, as shown in FIGS. 1 and 2 , the park gear 14 is coupled to a vehicle transmission output shaft 16 for rotation with the output shaft 16 about an axis 18 of the shaft when the vehicle is moving. The gear 14 has a plurality of circumferentially spaced apart teeth 20 extending outwardly around its periphery. Gaps 22 are defined between adjacent teeth 20 in an alternating pattern of teeth and gaps.
[0011] The park lock system 10 includes the lock mechanism 12 and an actuator 24 for selectively engaging the lock mechanism 12 with the park gear 14 . In the example shown, the lock mechanism 12 includes a pawl 26 pivoted at a first end about a pin 28 to move a second end including a lock tab 30 toward and away from the park gear 14 . This permits the pawl 12 to be moved between disengaged ( FIG. 1 ) and engaged ( FIG. 2 ) positions to selectively engage the pawl 26 with the park gear 14 . The lock tab 30 is adapted to engage a tooth 20 of the park gear 14 when the park lock mechanism 10 is actuated to lock the vehicle transmission in park. The pawl 26 may be yieldably biased, such as by a spring, toward its disengaged position where the lock tab 30 is free and clear of the park gear 14 to permit rotation of the park gear 14 . In this way, absent a force moving and holding the pawl 26 into its engaged position, the pawl 26 will normally be in its disengaged position.
[0012] The actuator 24 may include a motor 32 and a drive member 34 driven by the motor 32 to move the pawl 26 from its disengaged position to its engaged position. The motor 32 may be any suitable reversible electric motor 32 . The motor 32 is coupled to a threaded spindle 36 to rotate the spindle in forward and reverse directions and thereby move the drive member 34 . The drive member 34 travels along the spindle 36 in a direction dictated by the direction of rotation of the spindle 36 . In the implementation shown, the drive member 34 moves toward the motor 32 when the spindle 36 is rotated in the forward direction and the drive member 34 moves away from the motor 32 when the spindle 36 is rotated in the reverse direction.
[0013] In use, to engage the park lock system 10 the motor 32 is driven in its forward direction. This moves the drive member 34 toward the motor 32 along the spindle 36 until the drive member 34 engages the park pawl 26 . If the lock tab 30 of the pawl 26 is aligned with a gap 22 between adjacent teeth 20 in the park gear 14 , the pawl 26 is moved to its engaged position with the lock tab 30 received between adjacent teeth 20 as shown in FIG. 2 . To provide a force holding the park pawl 26 in its engaged position, the drive member 34 may remain engaged with the park pawl 26 . Gravity or another force (e.g. engine or transmission force), will generally cause some movement of the vehicle and corresponding rotation of the park gear 14 to firmly engage the lock tab 30 with one of the teeth 20 on the park gear 14 . This provides a positive stop to movement of the park gear 14 .
[0014] To shift the vehicle out of park, the park pawl 26 must be moved to its disengaged position. To do this, the motor 32 is driven in its reverse direction and the drive member 34 moves away from the motor 32 and the pawl 26 . As the drive member 34 disengages from the pawl 26 , the return spring biasing the pawl 26 moves the pawl 26 toward its disengaged position until the lock tab 30 is free and clear of the park gear 14 and the park gear can rotate without interference from the park pawl.
[0015] At least when the vehicle is parked on an incline, the force of gravity on the vehicle will tend to rotate the park gear 14 against and firmly into engagement with the lock tab 30 of the park pawl 26 . This can provide a significant force on the park pawl 26 such that when the park pawl 26 is moved to its disengaged position, the park pawl 26 may abruptly move out of its engaged position and a loud noise and abrupt (but usually slight) movement of the vehicle may occur. Noise may also be attributed to the sudden movement of the park gear 14 upon release of the park pawl 26 . The noise and vehicle movement can be startling or unsettling to some people.
[0016] To reduce or eliminate the noise and/or sudden movement of the vehicle upon disengagement of the park pawl 26 from the park gear 14 , a counterforce is provided to lessen (potentially reduce to zero) the force the park gear 14 places on the lock tab 30 at least when the vehicle is parked on a grade or incline above a threshold magnitude. The counterforce may be provided by an electric motor coupled to the output shaft 16 . The electric motor may provide a torque that counters the force tending to rotate the shaft 16 such that the force the park gear 14 provides on the lock tab 30 is reduced. In this way, the park lock system 10 is readily adaptable to an electric vehicle application where such an electric motor coupled to the output shaft 16 is already available. Of course, the counterforce could be provided in other vehicles including those using a combustion engine where the offsetting torque could be provided by the engine itself, or by another prime mover including an electric motor, if desired.
[0017] Accordingly, the park lock system 10 in operation may utilize any method of applying a counterforce or offsetting torque to lessen the force acting on the park lock mechanism 12 before the park lock mechanism 12 is disengaged from the park gear 14 . In operation, one method of applying a counterforce is shown in the flow chart of FIG. 3 . In general, that method for applying a counterforce or offsetting torque involves determining the amount of offsetting torque needed or desired at 40 and applying the determined torque to the shaft at 42 . Of course, other methods may be used, for example, applying an offsetting torque to the shaft 16 until only a predetermined force remains on the park pawl 26 (that is, reducing the force on the park pawl 26 until the force is below a threshold). In another embodiment, the park pawl 26 and/or the drive member 34 can be configured so engaging surfaces cooperate to facilitate a smooth, uninterrupted engagement/disengagement of the contacting parts ( 26 and 34 ) and engagement/disengagement of the lock tab 30 with the park gear 14 . For example, one or more contacting parts that engage/disengage may include a chamfered surface, curved surface profile, or otherwise complementary surface profile.
[0018] In more detail, the method of FIG. 3 includes a step 40 of determining the force acting on the park pawl 26 . This may be accomplished in many ways. One way is to sense or determine a longitudinal acceleration of the vehicle (generally, the attitude or relative height of a front of the vehicle compared to the back end of the vehicle). The longitudinal acceleration may be measured using an inertial sensor such as an accelerometer or tilt sensor, by way of a couple examples, without any limitation intended. From the longitudinal acceleration, the grade or incline on which the vehicle is parked may be calculated at 44 and a suitable counteracting or offsetting torque can be calculated based on the grade where the force applied to the park pawl 26 at the calculated or determined grade is known or can be determined as a function of the vehicle weight.
[0019] Then, if there is a request 46 to shift the vehicle out of park and to another gear, the motor may be energized to provide the desired counteracting torque to the shaft 16 . The counteracting torque applied can be sensed at 48 , and when the desired counteracting torque, or a greater torque, has been applied to the shaft 16 , the counteracting torque is no longer applied and the vehicle may then be shifted out of park at 50 and into another gear. A suitable controller, which may be a stand alone unit or part of an existing vehicle controller or control system, may be used to determine the offsetting force needed to be applied to the output shaft 16 , and to control and monitor the application of the offsetting force to the output shaft 16 .
[0020] Another way to determine the force on the park pawl 26 is to actually sense the force acting on the park pawl 26 , such as with a strain gauge or other sensor. Such a force sensor 60 is shown diagrammatically in FIG. 1 on the lock tab and may be engaged by teeth 20 of the park gear 14 in use. After or while the offsetting force is provided, this force sensor 60 could also be used to determine when the force on the park pawl 26 has been reduced sufficiently to permit disengagement of the park pawl 26 . Further, an initial determination of the magnitude of the load on the park pawl 26 is not needed. Instead, the offsetting force could be provided until the net force on the park pawl 26 is below a desired threshold. In other words, the magnitude of the offsetting force can be increased until the force on the park pawl 26 is decreased to a desired magnitude. In this example, an accelerometer or inclinometer could be used to determine the direction of the force to be applied to the output shaft 16 to offset the force on the park pawl 26 (where the direction will be different if the vehicle is parked with its front end facing uphill than if the vehicle is parked with its front end facing downhill).
[0021] Other steps may be included or substituted for steps identified in the representative flow chart and described method. For example, before beginning the method a determination can be made at 52 as to whether the vehicle is stationary and in park. If not, then no counteracting torque should be applied so the method should not be performed. Another step 54 may be to determine if the vehicle is parked on an incline that is greater than a threshold incline. The threshold incline can be chosen so that on inclines less than the threshold, the force on the pawl 26 will be within an acceptable range without any offsetting force applied to the output shaft 16 such that disengagement of the park pawl 26 will not cause unacceptable noise or vehicle movement. In this way, if the vehicle is not parked on a greater than threshold incline, then no offsetting force need be applied to the output shaft 16 and the method can be stopped.
[0022] Also, a system check may be provided at 56 before the counteracting torque is applied. The system check may include one or more steps designed to prevent application of the counteracting torque in certain conditions. For example, the system check may verify one or more of the following: 1) that the park lock is not already disengaged; 2) the vehicle currently is on a grade; 3) there is an operator request to disengage park; 4) the vehicle brake pedal has been/is applied (perhaps by sensing brake pedal switch(es) or receiving an indication from the system or vehicle ECU); 5) a signal indicative of the vehicle grade that was stored from the previous ignition cycle (e.g. when the vehicle engine or motor was shutoff) is within a threshold value of the current signal regarding the grade the vehicle is currently on; 6) the integrity of the indicated/signaled grade is verified (perhaps through a Controller Area network (CAN), Cyclic Redundancy Check (CRC) and/or Rolling Counter (RC) check; 7) a traction motor angular displacement is less than a threshold; and 8) that the counteracting torque applied (achieved torque) is within a threshold of the desired or calculated torque intended to be applied. In at least some implementations, the counteracting torque would not be applied if any of the above conditions were not satisfied. The system check could also verify that sufficient brake system pressure exists to hold the vehicle stationary if the park lock is disengaged, and that a hand brake has been applied before disengaging the park lock, if desired.
[0023] Of course, other method steps may be added or substituted for the steps shown in FIG. 3 , and not all steps are needed in any desired method. Further, the steps could be done in a different sequence or in a different combination of steps to provide an offsetting torque to the output shaft or park gear.
[0024] Further, while a particular park lock mechanism 12 and system 10 are described, the method of providing an offsetting force to the transmission output shaft 16 could be used with any park lock mechanism 12 and system 10 . That is, the electric motor driven system, including the drive member 34 , pawl 26 , etc, are not needed. The force on any type of vehicle park lock system 10 could be reduced by providing a counteracting or offsetting force or torque to the transmission output shaft 16 or park gear 14 . | A method of operating a park lock mechanism in a vehicle includes determining a force acting on a vehicle park lock mechanism when the vehicle is in park, and providing an offsetting force to counteract the force on the park lock mechanism before the vehicle is shifted out of park. In doing so, harshness and noise that may be associated with shifting a vehicle out of park, especially when the vehicle is parked on an incline, can be reduced or eliminated. |
BACKGROUND AND SUMMARY
[0001] The present invention relates generally to UV fluid treatment systems and specifically to such systems and methods that incorporate electrodes to facilitate advanced oxidation processes (AOP). Such electrodes include those that are based on electrolytic production of hydrogen peroxide, or are optimized for the production of hydrogen peroxide and/or for the destruction of organic contaminants in industrial wastewater, including mixed metal oxide electrodes having two kinds of metal oxides, such as those disclosed in U.S. Pat. No. 8,580,091 (issued Nov. 12, 2013), included herein by reference as if fully re-written herein.
[0002] AOP that generally use UV plus peroxide can be used for many water and wastewater (i.e. fluid) based oxidation processes. Conventional peroxide systems are chemical based and generally require the dangerous chemical to be tankered in and stored. The present invention offers many advantages over what is done now.
[0003] In one embodiment, the present invention incorporates an L-shaped electrode, placed upstream from the UV lamps, that forms hydroxyl radicals. The electrode is inserted into the UV reactor through the existing access hatch.
[0004] In one embodiment, elongated, tubular UV lamps are used as the UV radiation source. Such lamps produce the least UV at their ends. In other words, the radiation intensity is diminished resulting in a lower UV dosage delivered near the lamp ends.
[0005] Additionally, elongated medium pressure (MP) lamps blacken over time and the arc shortens. These characteristics result in diminished UV dosages in UV reactors having such lamps oriented transversely to the fluid flow. Accordingly, it would be advantageous to direct the flow of fluid away from the ends and towards the center of such elongated lamps. It is also advantageous to move the fluid away from the top & bottom of the chamber (i.e. vertically). The present invention overcomes these, as well as other disadvantageous that will be apparent to those of skill in the art, by tapering the electrode veins so as to direct the flow of fluid towards the center of the elongated lamps—the area of highest UV fluence.
[0006] In one embodiment, the electrodes are titanium mesh, coated with Iridium and/or Ruthenium. In one embodiment, the electrodes are made from a mesh-like structure which increases surface area and disrupts the fluid flow pattern more than a solid sheet would; which is advantageous. In one embodiment, the present invention incorporates an electrode inserted into an access hatch of a UV reactor, immediately upstream of the UV radiation source.
[0007] By applying a voltage to the electrode the water is hydrolyzed and hydroxyl radicals are formed immediately before the UV system lamps (aka UV radiation source). When the hydroxyl radicals interact with the UV lamps an advanced oxidation process occurs. This process can be used to oxidize many contaminants out of many different types of water, swimming pool, or other recreational water and waste water; including water for reuse, as well as ultra-pure water.
[0008] When such a system is operated with the electrode in front (i.e. upstream) of the UV system, it acts as an advanced oxidation process. When the system is operated with the electrode behind (i.e. downstream) the UV lamp, and salt is introduced into the water upstream of the UV lamps, the system will provide a self-contained UV system plus residual chlorine provider.
[0009] One advantage of the L-shaped electrode of the present invention is to maximize surface area. The electrode is powered by DC voltage, and it has variable output base on the amperage and DC voltage that is fed to it. The DC voltage can switch, so as to assist in the removal of any scale of hardness from the electrode surface. In one embodiment, the voltage polarity (relative to the cathode and anode) is switched so as to assist in the removal of any scale of hardness from the electrode surface.
[0000] H 2 O 2 +hν→2 • OH Φ=1.0
[0010] A reduction reaction takes place at the negatively charged cathode with electrons (e−) from the cathode being given to hydrogen cations to form hydrogen gas (the half reaction balanced with acid):
[0011] Reduction at cathode: 2 H + (aq)+2e − →H 2 (g)
[0012] An oxidation reaction occurs at the positively charged anode, generating oxygen gas and giving electrons to the anode to complete the circuit:
[0013] Anode (oxidation): 2 H 2 O(l)→O 2 (g)+4 H + (aq)+4e−
[0014] The same half reactions can also be balanced with base as listed below. Not all half reactions must be balanced with acid or base. Many do, like the oxidation or reduction of water listed here.
[0015] Cathode (reduction): 2 H 2 O(l)+2e−→H 2 (g)+2 OH − (aq)
[0016] Anode (oxidation): 4 OH − (aq)→O 2 (g)+2 H 2 O(l)+4 e −
[0017] Combining either half reaction pair yields the same overall decomposition of water into oxygen and hydrogen:
[0018] Overall reaction: 2 H 2 O(l)→2 H 2 (g)+O 2 (g)
[0019] The number of hydrogen molecules produced is thus twice the number of oxygen molecules. Assuming equal temperature and pressure for both gases, the produced hydrogen gas has therefore twice the volume of the produced oxygen gas. The number of electrons pushed through the water is twice the number of generated hydrogen molecules and four times the number of generated oxygen molecules. Some of the other advantages of the present invention include:
[0020] Production of active substances, immediately adjacent to the UV lamp(s) with no harmful disinfection by products;
[0021] Elimination of transport, storage, handling of Hydrogen Peroxide inherent with conventional systems;
[0022] Scalable, no moving parts; and
[0023] The L-shaped electrode improves water flow patterns, which therefore improve the performance of the UV system.
Initiation:
[0000] H 2 O 2 /HO 2 − =hν→ 2HO • Propagation:
[0000] H 2 O 2 /H 2 − +HO • →H 2 O/OH − +HO 2 •
[0000] H 2 O 2 +HO 2 • /O 2 • →HO • +H 2 O/OH − +O 2
Termination:
[0000] HO • +HO • →H 2 O 2
[0000] HO • +HO 2 500 /O 2 • →H 2 O/OH − +O 2
[0000] HO 2 • +HO 2 500 /O 2 • →H 2 O 2 /HO 2 − +O 2
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 depicts a perspective upper view of one embodiment of the electrode of the present invention.
[0028] FIG. 2 depicts a perspective rear view of one embodiment of the electrode of the present invention.
[0029] FIG. 3 depicts a perspective view of the UV reactor in accordance with one embodiment of the invention.
[0030] FIG. 4A depicts a partial, cross sectional side view of one embodiment of the present invention.
[0031] FIG. 4B depicts a top view of one embodiment of the present invention wherein the veins are parallel.
[0032] FIG. 4C depicts a top view of an alternative embodiment of the present invention wherein the veins are tapered.
REFERENCE NUMERALS IN DRAWINGS
[0033] The table below lists the reference numerals employed in the figures, and identifies the element designated by each numeral.
[0034] 1 UV reactor 1
[0035] 2 reactor access hatch 2
[0036] 3 UV radiation source 3
[0037] 4 directional fluid flow arrows 4
[0038] 5 electrode 5
[0039] 6 cathode 6
[0040] 7 anode 7
[0041] 8 upper vertical portion 8 of cathode 6
[0042] 9 lower horizontal portion 9 of cathode 6
[0043] 10 upper vertical portion 10 of anode 7
[0044] 11 lower horizontal portion 11 of anode 7
[0045] 12 tab 12 of upper, vertical portion 8 of cathode 6
[0046] 13 tab 13 of upper, vertical portion 10 of anode 7
[0047] 14 hole 14 in upper, vertical portion 8 of cathode 6
[0048] 15 hole 15 in upper, vertical portion 10 of anode 7
[0049] 16 holes 16 in lower, horizontal portion 9 of cathode 6
[0050] 17 holes 17 in lower, horizontal portion 11 of anode 7
[0051] 18 threaded titanium rod with nut 18
[0052] 19 titanium spacer 19
[0053] 20 threaded non-conducting rod with nut 20 (e.g. PVC)
[0054] 21 non-conducting spacer 21
[0055] 22 first connection terminal 22
[0056] 23 second connection terminal 23
[0057] 24 hydrogen exhaust port 24
DETAILED DESCRIPTION
[0058] In one embodiment, in a UV (i.e. ultra violet) fluid reactor 1 , an electrode 5 comprises, a plurality of L-shaped, substantially planar cathodes 6 ; and a plurality of L-shaped, substantially planar anodes 7 .
[0059] In one embodiment, the UV radiation source comprises a plurality of tubular, medium pressure, mercury vapor lamps, enclosed by a quartz sleeve. Those of skill in the art will appreciate that other UV radiation sources can be used (e.g. amalgam lamps) without compromising the spirit of the invention.
[0060] The plurality of L-shaped, substantially planar cathodes 6 are electrically connected to each other and are at substantially a first voltage. The plurality of L-shaped, substantially planar anodes 7 are electrically connected to each other and are at substantially a second voltage. In one embodiment, the first and second voltages differ by approximately 36 volts (e.g. the first voltage is zero and the second voltage is 36 volts). In one embodiment, the range of DC voltage is 0-36 volts, and 0-12 amps.
[0061] The voltage polarity can be switched, depending on how fouled the electrodes become. Reversing the polarities in such a manner achieves the advantage of mitigating scaling and/or the accumulation of other undesirable particles and/or substances. The interval of such reversal is calibrated according to the application. For example, in one embodiment, a timer is used and the interval (i.e. duty cycle) varies from once per day (worst case−heavy fouling/scaling) to once per month (soft water).
[0062] Each cathode 6 is electrically connected (and likewise for each anode 7 ) to each other. In one embodiment, the connectivity is achieved by inserting threaded titanium rod 18 (i.e. threaded conducting rod) through hole 14 of each upper, vertical portion 8 of each cathode 6 , using titanium (i.e. conducting) spacers 19 as necessary to achieve the desired distance between each cathode. The connectivity of each anode 7 is achieved by inserting threaded titanium rod 18 (i.e. threaded conducting rod) through hole 15 of each upper, vertical portion 10 of each anode 7 , using titanium spacers 19 as necessary to achieve the desired distance between each anode.
[0063] The electrically connected cathodes 6 are non-electrically connected to the electrically connected anodes 7 by first arranging the cathodes and anodes, relative to each other, so that there is one anode between every two cathodes and vice versa (except on the ends); and so that holes 16 & 17 are coaxially aligned. In other words, the cathodes and anodes are alternatingly, cooperatively arranged. This arrangement is depicted in FIGS. 1 & 2 .
[0064] To achieve the non-electrical connection of cathodes 6 to anodes 7 , non-conducting (e.g. PVC) threaded rods 20 are inserted through each of holes 16 in each lower, horizontal portion 9 of each cathode 6 as well as through each of holes 17 in each lower, horizontal portion 11 of each anode 7 ; using non-conducting spacers 21 as necessary to achieve the desired distance between each respective cathode and anode.
[0065] It is to be understood that the number of cathode/anode pairs can be varied to achieve differing levels of reaction. For example, FIGS. 1 , 2 , 4 B & 4 C depict six pairs.
[0066] In one embodiment, the various cathodes 6 and anodes 7 are made from a mesh material. However, a solid material can be substituted. In another embodiment, each cathode and anode are made from a titanium mesh material that is coated with iridium and/or ruthenium. In one embodiment, mixed metal oxide, iridium and ruthenium oxide coated titanium substrates (e.g. grade 1 or 2, 0.063 inches thick) are used. It is to be understood that while titanium is used in some embodiments for the various electrodes, threaded rods, bolts, and spacers, other conducting metals may be used.
[0067] As shown in FIGS. 1 & 2 , first connection terminal 22 is electrically connected to tab 12 of upper, vertical portion 8 of cathode 6 . Likewise, second connection terminal 23 is electrically connected to tab 13 of upper, vertical portion 10 of anode 7 . Electrode 5 is then inserted into access hatch 2 of reactor 1 as shown in FIGS. 3 & 4A .
[0068] In one embodiment, each cathode 6 and each anode 7 are substantially parallel to each other ( FIG. 4B ). In another embodiment ( FIG. 4C ), the cathodes and anodes are longitudinally tapered to affect the fluid flow towards the lateral center of the reactor. This arrangement necessarily implies the electrode must be upstream from the radiation source in this particular embodiment. The longitudinal tapering is more fully appreciated from the plan view as depicted in FIG. 4C . UV radiation source 3 is elongated and oriented transverse to fluid flow (e.g. FIG. 3 ); the electrodes act as veins to direct the fluid flow towards the arc (i.e. the center of an elongated UV lamp) and away from the ends of the lamp. The veins are tapered, relative to the horizontal plane, so as to move the fluid towards the center of the arc. A distinct advantage is achieved by moving the fluid (e.g. water) away from the ends of the lamp.
[0069] Those of skill in the art will appreciate that such an arrangement will direct the flow of fluid away from the ends of an elongated radiation source (e.g. a tubular medium pressure mercury vapor lamp) arranged perpendicularly (i.e. transverse) to fluid flow, towards the center of the radiation source. A distinct advantage is thereby achieved because the radiation intensity of such a radiation source is diminished somewhat towards the ends thereof.
[0070] In one embodiment, the veins (i.e. cathodes and anodes) are parallel (e.g. FIG. 4B ), and the distance between each vane is in the range of from about 0.2 to 0.4 inches. In another embodiment, the veins are tapered (e.g. FIG. 4C ) and the distance between veins (downstream end) is in the range of from about 0.1 to 0.2 inches; and the distance between veins (upstream end) is in the range of from about 0.2 to 0.5 inches. Those of skill in the art will appreciate that the degree of tapering can be adjusted to accommodate differing reactor and/or lamp geometries.
[0071] In one embodiment (e.g. FIG. 3 ), access hatch 2 has hydrogen exhaust port 24 . It is to be noted that port 24 does not have to be placed in hatch 2 . Alternatively, the exhaust port can be placed in the reactor itself.
[0072] Those of skill in the art will appreciate that the size of electrode 5 is proportional to the size of reactor 1 . Thus, various sizes are possible in accordance with conventional reactors. | A system and method for applying an advanced oxidation process to a UV fluid reactor. An L-shaped electrode is connected to a UV reactor hatch and inserted into the reactor upstream from a UV radiation source. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to Spanish patent application Ser. No. 200601682 filed Jun. 22, 2006, the contents of which are hereby incorporated by reference in their entirety.
DESCRIPTION
[0002] 1. Field of the Invention
[0003] The present invention concerns a new suspension medium for red blood cells, for carrying out the main immunohaematological agglutination tests requiring erythrocytes which are performed in hospitals and blood-transfusion centres. The determination of the serum group, the detection and identification of irregular antibodies, the preparation of positive and negative controls, and the need to preserve samples for investigation of anomalous results, require red blood cells, re-suspended in an aqueous medium, which maintain their functionality.
[0004] 2. State of the Art
[0005] The clinical advance provided by blood transfusion brought with it a development of immunohaematology. Without this, the number of transfusions which are carried out at present on accident victims, in surgery or in the treatment of leukaemia, cancer and other illnesses would not have been possible. In Spain, during 2004 a total of 1.6 million blood donations were made (1), in the U.S., it is estimated that around 15 million bags of blood are donated per year (2) and the World Health Organisation, on the basis of data from 178 countries, estimates at 81 million the total blood units donated annually (3). This number of donations would be of no use without prior immunohaematological determination. The main blood groups which are determined are the ABO system and the RH system, and particularly of this second system, antigen D (RH1).
[0006] In an emergency situation, all individuals may receive red blood cells or red corpuscles of group O, and AB individuals may receive red blood corpuscles of any ABO group. Hence, individuals of group O are known as universal donors and AB individuals as universal recipients. The acceptance of red corpuscles or red blood cells coming from a person of a particular blood group by another person is conditional on the antibodies present in the plasma of the recipient. Thus, individuals of group O have antibodies against antigens A and B, individuals of group A have antibodies against B, and vice versa for individuals of group B, and individuals of group AB do not have antibodies. Consequently, it is not the red blood cells, but the plasma of AB individuals that can be donated to all blood groups.
[0007] The basis of immunological analysis is then the determination of the ABO group and the RH group. The ABO system is determined by antigens and antibodies (known as regular antibodies), while the RH system and the other systems only have antibodies (known as irregular antibodies) as a consequence of pregnancy and of transfusion practice. However, in spite of their low frequency in the population, the determination of irregular antibodies is of the utmost importance, and is being implemented in all hospitals and blood transfusion centres in order to avoid risks and to obtain extremely safe transfusions. Neonatal determinations have also been implemented, both for diagnosing possible haemolytic diseases of the newborn, and also for prophylaxis to be given to the mother in the event that she is Rh− (lack of antigen D) and the child is Rh+ (exhibits antigen D).
[0008] In immunohaematology, the introduction of new technologies for typing red blood cells, compatibility tests and detection of regular and irregular antibodies have represented the most significant advances in this area. The improvements have been related to the components which favour specific agglutination (e.g. Coombs solution, LISS solution (low ionic strength solution), solutions with albumin, solutions with proteolytic enzymes or other potentiators of the antigen-antibody union), the improvement of reactive antibodies (e.g. monoclonal antibodies), and also new or substantially different methodologies becoming available for displaying agglutination (e.g. micro-sheet and gel technique). The appearance of the technique of microtubes in a column, also known as gel or card technique, provides the basis for the modernisation of immunohaematology. Since its appearance in 1986, the technique of microtubes in a column (4) has not ceased to experience spectacular growth. Owing to its ease of automation, this methodology will displace the rest of the techniques, being forecast as the only one which will remain for phenotypic determination. Together with the genotypic technique which prevails, they will form the basis for immunological analysis. At present, the majority of methodologies for genotypic determination are in the preliminary stages, at all events limited to research laboratories.
[0009] The gel technique separates the agglutinated cells from those which have not agglutinated, via centrifuging in a filtration matrix formed by small balls of gel (EP 194212, EP 305337), of glass or other spherical material (EP 485228, EP 725276, EP 755719). In the upper part of the microtube, the reaction chamber, located above the gel column, the samples are dispensed. In the column in which the gel or filtration matrix is contained, there is a buffered solution which, depending on the analysis, may contain specific antibodies (e.g. anti-A, anti-B or anti-D) or human antiglobulin (human anti-IgG or anti-IgM antibodies), known as Coombs solution. The filtration matrix is composed of spherical particles which settle in a buffered aqueous solution. In order to display the immunohaematological agglutination, centrifuging is carried out, forcing the cells (red blood cells) to pass through the filtration matrix. The space which remains between particles is large enough to allow the cells which have not agglutinated, that is, individual cells, to pass through. While in the event that agglutination has taken place, the agglutinated cells are retained between the balls. Although, strictly, it is a qualitative technique, the passage through the filtration matrix makes it possible to distinguish different degrees of agglutination. In positive samples in the upper part of the gel the very strong agglutinates will be retained, while the weak agglutinates may pass a certain distance through the matrix, remaining half-way, for example. The absence of agglutination will mean that all the cells reach the base of the microtube (negative reaction). As occurs in conventional immunohaematology, owing to the intense red colour of the red blood cells, the technique does not require any marker or amplifier of the antigen (red blood cells)—antibody union.
[0010] The gel technique has made it possible to physically separate the positive results from the negative results, i.e. the positives in the upper part of the gel (high intensity agglutinate), along the column (medium or weak agglutinates), and in the lower part of the column the negative results (non-agglutinated red blood cells).
[0011] In the immunohaematological tests for detecting regular and irregular antibodies in plasma or serum, reagent red blood cells are used. Said red blood cells are prepared in a solution for the purpose of maintaining their functionality and integrity for a certain period of time, customarily between 1 and 4 weeks. In the blood bank laboratories or those responsible for blood transfusion, the red blood cells with specific antigens are selected so that they can act as reagent red blood cells in each of the immunohaematological tests. The combinations necessary for preparing the screening cells, assembly of 2, 3 or 4 red blood cells with concrete antigenic specificities which make it possible to detect antibodies, or panels, assembly of 11 or more red blood cells which make it possible to identify the specificity of the antibodies detected, are not easy to produce and they may also prove of difficult execution in medium-sized centres. The difficulties of obtaining said screening cells or panels, added to the need to prepare these reagent red blood cells frequently, are very familiar to any expert in the field, as is the essential need to have available a suspension solution for red blood cells or a diluent for red blood cells. In addition, screening cells or panels are also prepared with an enzymatic treatment (e.g. papainization) in order to potentiate the reactivity of specific blood groups. The blood groups potentiated by this treatment are well known to any expert in the field.
[0012] Diluent solutions are currently used which are variations on the original Alsever solution. These solutions generally contain an anticoagulant (e.g. citrate), a phosphate buffer, an energy source (e.g. glucose), purines and nucleosides (e.g. adenine and inosine), sodium chloride, and preservatives (antibiotics). However, the reagent red blood cells prepared with these conventional solutions may present problems in gel technology. The physical separation which has permitted gel technology may be affected, since some of the non-agglutinated red blood cells are often retained along the column. This non-specific retention produces false positive results, since it is confused with a medium or weak agglutinate.
[0013] The suspension solution for the reagent blood cells should make it possible to maintain the functional characteristics and their capacity for passing through the gel column to the lower part of the column in the event that they have not agglutinated. These characteristics should be maintained for the maximum time possible, owing to the previously stated difficulties of preparing red blood cells in immunohaematology laboratories. The parameters which must be maintained constant over this period are, among others, the pH, the osmolarity and the ionic strength. Likewise, it is essential to provide glucose and adenine so that the red blood cells maintain their viability. The assembly and concentration of these substances bring about an increase in the ionic strength which is reduced by the addition of glycine. The red blood cells have lost the genetic nucleus and any capacity for biosynthesis, so that the addition of this amino acid is in no way related to protein synthesis.
DESCRIPTION OF THE INVENTION
[0014] In the research carried out by the inventors in order to reduce the loss of specificity which is observed in reagent red blood cells, it was surprisingly discovered that the addition to these diluent solutions for reagent red blood cells of combinations of amino acids apart from glycine, in concentrations higher than those necessary for reducing the ionic strength, makes it possible to reduce the loss of specificity which is observed in reagent red blood cells, that is, considerably reduces the non-specific retention of non-agglutinated red blood cells along the gel column.
[0015] For this reason, a description will be given in the present patent application of the compositions of diluent solutions for reagent red blood cells which make it possible to maintain the integrity and functionality of the reagent red blood cells over a prolonged period of time, for example, 8 weeks. During this period of time, the red blood cells preserve their capacity for passing through the gel or any other narrow space and the capacity for not agglutinating non-specifically, maintaining the characteristic of deformability, integrity and antigenicity, so that they can be used as an immunohaematological reagent for the determination of the serum group, a test for detecting regular antibodies, and in the investigation and identification of irregular antibodies.
[0016] The incorporation of the combinations of amino acids according to the invention in a diluent solution or suspension medium for red blood cells maintains the red blood cells in a state of integrity and with characteristics of functionality which permit their use in gel technology. The passage of the red blood cells through a gel matrix exhibits no difference in retention between the fresh red blood cells (initial preparation time for the suspension) and those kept for 8 weeks. That is, the amino acids incorporated in the diluent solution make it possible to maintain in the red blood cells the initial physical characteristics of the fresh red blood cells. The longer the preparation of red blood cells takes, the more possibilities exist for the appearance of false positive results. The reagent red blood cells are living cells, so that degradation in a relatively short time is very well known to any expert in the field.
[0017] The gel technique permits visual quantification between agglutinates of different size. The results of agglutination are customarily designated by a score graduation similar to that of Table 1. As described previously, non-agglutinated red blood cells, red blood cells which should be found at the bottom of the column, may present results similar to +/−and 1+ which would give an incorrect diagnosis, an incorrect positive interpretation.
[0000]
TABLE 1
Interpretation
Grade
Score
Description
Negative:
−
0
Band of red blood cells at the bottom
of the column, rest of column without
visible agglutinates.
Positive:
+/−
3
Sparse agglutinates of small size in the
lower half of the column, with red
blood cells at the bottom of the
column.
1+
5
Some agglutinates of small size in the
column.
2+
8
Agglutinates of small or medium size
along the column.
3+
10
Upper band of agglutinates, of medium
size, in the upper half of the column.
4+
12
Band of agglutinated red blood cells in
the upper part of the column.
[0018] The addition of the combinations of amino acids according to the present invention to a liquid which contains the customary constituents known to any expert in the field, considerably reduces non-specific retentions of the reagent red blood cells. These constituents are phosphate buffer, sodium chloride, glucose, adenine, preservatives (e.g. chloramphenicol and neomycin), EDTA and glycine.
[0019] The concentration of each of the amino acids which form the amino acid combinations of the present invention may vary according to their solubility in aqueous solutions and such that, as a whole, the total osmolarity of the diluent solution for red blood cells is within a range of 100-700 milliosmol/kg.
[0020] A description will now be given of examples of combinations of amino acids in a suspension solution for red blood cells according to the present invention. For example, if in a base liquid without amino acids other than glycine (liquid No. 1) amino acids are added (liquid No. 2), the total number of false positives obtained in 50 individual determinations over 10 weeks is reduced from 13 to zero in a screening of two cells by the Coombs technique for irregular antibodies. It should be mentioned that 10 weeks from the manufacture of the reagent red blood cells is a period which exceeds the conventional limits for preservation of the reagent red blood cells. Another way of quantifying the differences between liquids is to compare the average scores obtained from all the individual determinations. The average scores obtained in 50 determinations of 10 phials evaluated over 10 weeks for liquid No. 1 and liquid No. 2 are, respectively, 2.44 and 1.52. For a screening technique of 2 cells with papainized red blood cells, the number of false positives is reduced from 40 to 7 between the liquid without amino acids (liquid No. 1) and the liquid with amino acids (liquid No. 2). The 7 false positives were obtained in week 10, while the false positives for liquid No. 1 are obtained in shorter times from the preparation of the suspension. Comparing the average scores in this screening technique of 2 cells with papainized red blood cells also clearly shows the differences between liquids, the average score value of 50 determinations for liquid No. 1 and liquid No. 2 being 5.92 and 1.84 respectively.
[0000]
Liquid No. 1
Ingredients
Concentration (g/l)
KH 2 PO 4 (anhydrous monopotassium phosphate)
1.36
Na 2 HPO 4 (disodium phosphate)
1.42
Chloramphenicol
0.17
Neomycin
0.10
NaCl
1.0
Dextrose (anhydrous D-glucose)
3.5
Adenine
0.02
EDTA (dihydrated disodium)
2.80
Glycine
14.70
[0000]
Liquid No. 2
Ingredients
Concentration (g/l)
KH 2 PO 4 (anhydrous monopotassium phosphate)
1.36
Na 2 HPO 4 (disodium phosphate)
1.42
Chloramphenicol
0.17
Neomycin
0.10
NaCl
1.0
Dextrose (anhydrous D-glucose)
3.5
Adenine
0.02
EDTA (dihydrated disodium)
2.80
Glycine
14.70
L-valine
3.20
L-methionine
2.52
L-leucine
2.60
L-isoleucine
6.48
[0021] If in a base liquid (e.g. liquid No. 1), apart from the amino acids, other components described and widely used in red blood cell solutions are incorporated, such as inosine, citrate, citric acid and bicarbonate (e.g. liquid No. 3), the effect of the amino acids may be even greater. In the case of a screening of two cells by the Coombs technique for irregular antibodies, no false positives are obtained in 50 determinations over 10 weeks, and the average score is 0.96. Nor in the screening of two papainized cells are false positives obtained, and the average score is 0.80.
[0000]
Liquid No. 3
Ingredients
Concentration (g/l)
KH 2 PO 4 (anhydrous monopotassium phosphate)
0.30
Na 2 HPO 4 (disodium phosphate)
0.28
Chloramphenicol
0.17
Neomycin
0.10
NaCl
1.00
Dextrose (anhydrous D-glucose)
3.50
Adenine
0.02
EDTA (dihydrated disodium)
2.80
Inosine
0.02
NaHCO 3
0.80
Na 3 dihydrated citrate
2.00
Monohydrated citric acid
0.18
Glycine
6.00
L-valine
3.20
L-methionine
2.52
L-leucine
2.60
L-isoleucine
6.48
[0022] It has been stated (5) that specific antigens of blood groups (M, Pl, Fy a , Fy b , S and s) may be lost or reduce their antigenicity on re-suspending the red blood cells in solutions of low ionic strength. The addition of amino acids does not alter the expression of said antigens, the same reactivity, antigenic potency, being observed from the preparation of the suspension up to 10 weeks later, i.e. during the useful life of the product.
[0023] The haemolysis observed in the liquids which incorporate amino acids is lower than that obtained with the liquid without amino acids or only with glycine. This indicates that the addition of these substances does not have a negative effect on the osmotic fragility of the cell.
[0024] In the case of the reagent red blood cells for the determination of the serum group, that is, the detection of regular antibodies, the suspensions of red blood cells which incorporate amino acids exhibit correct functioning.
[0025] In serum group techniques with a base liquid without amino acids other than glycine, liquid No. 1, in 240 determinations using 4 serum group cells (A 1 , A 2 , B and O) over 10 weeks, 187 false positives were obtained, while if amino acids are added, liquid No. 2 and liquid No. 3, the total number of false positives is reduced to zero. The false positives of liquid No. 1 are obtained starting from 2 and 4 weeks from the preparation of the suspension of red blood cells, while with the liquids which incorporate amino acids, 10 weeks from their manufacture, still no false positives are observed. The average scores from 240 determinations using 4 serum group cells, with 10 phials for each cell, evaluated over 10 weeks for liquid No. 1, liquid No. 2 and liquid No. 3 are, respectively, 4.06, 1.37 and 0.94.
[0026] The addition of amino acids other than valine, leucine, isoleucine and methionine, including non-polar aliphatics and those which contain sulphur, also has the effect of reducing non-specific retentions. For example, with liquid No. 4, which contains non-polar aliphatic amino acids, aromatic amino acids, hydrophilic amino acids and polar amino acids with positive, negative or neutral charge, a reduction in non-specific retentions of red blood cells in the gel column is likewise obtained.
[0000]
Liquid No. 4
Ingredients
Concentration (g/l)
KH 2 PO 4 (anhydrous monopotassium phosphate)
0.30
Na 2 HPO 4 (disodium phosphate)
0.28
Chloramphenicol
0.17
Neomycin
0.10
NaCl
1.00
Dextrose (anhydrous D-glucose)
3.50
Adenine
0.02
EDTA (dihydrated disodium)
2.80
Inosine
0.02
NaHCO 3
0.80
Na 3 dihydrated citrate
2.00
Monohydrated citric acid
0.18
Glycine
6.00
L-valine
1.60
L-methionine
1.26
L-leucine
1.30
L-isoleucine
3.24
L-phenylalanine
2.00
L-lysine
1.22
L-histidine
0.50
L-tryptophan
0.50
L-arginine
1.60
L-threonine
1.10
[0027] By means of the present invention it has been possible to increase significantly the useful life in storage of suspensions of red blood cells for the purpose of analysis, from the customary period of four weeks to a minimum period of eight weeks, as shown by the tests performed.
BIBLIOGRAPHY
[0000]
(1) Federación Espanola de donantes de sangre (Spanish Blood Donor Federation). www.donantesdesangre.net. July 2005.
(2) Facts about blood . American Association of Blood Banks (2004).
(3) Global Database on Blood Safety: Report 2001-2002. Blood Transfusion Safety, Essential Health Technologies, World Health Organization. Geneva, Switzerland.
(4) The gel test: A new way to detect cell antigen - antibody reactions . Y. Lapierre et al. Transfusion 33:639-643 (1990).
(5) The preservation of red cell antigens at low ionic strength . J. C. Allan et al. Transfusion 30:423-426 (1990).
[0033] Although the invention has been described with respect to preferred exemplary embodiments, these should not be regarded as limiting the invention, which will be defined by the widest interpretation of the following claims. | The present invention relates to a new suspension medium or diluent solution for red blood cells for use in haematological methods. The suspension medium or diluent solution for red blood cells may comprise a combination of two or more amino acids of any group, and preserves the red blood cells in the sample for at least 8 weeks. |
BACKGROUND OF THE INVENTION
[0001] This application relates to a magnetic drive centrifugal pump.
[0002] Magnetic drive centrifugal pumps include a wet portion, which contains the process fluid that is being pumped, and a dry portion having a drive, which provides power to the pump fluid. The dry portion is exposed only to the atmosphere surrounding the pump. In one typical magnetic drive design, an inner and outer drive are separated by a containment shell, which prevents the pump fluid from escaping to the environment. The outer drive, which is usually driven by an electric motor, is located in the dry portion and magnetically drives the inner drive in the wet portion that is attached to a pump impeller. Since magnetic drive pumps are sealless, they are often selected to pump very acidic or caustic process fluids, such as hydrochloric acid, nitric acid and sodium hypochlorite.
[0003] Both the outer and inner drives have a series of magnets mounted around their peripheries. Each magnet is synchronously coupled to a respective magnet that is of an opposite pole on the other drive. The attraction between the magnets results in a magnetic coupling between the two drives causing the inner drive to rotate at the same speed of the outer drive, which is driven by the motor. The inner and outer drives must be located relatively close together for efficient power transmission, which requires a relatively small clearance to be maintained between the containment shell and each drive. In one example, the clearance is approximately 0.060 inch.
[0004] In one type of magnetic drive pump, the inner drive magnets are primarily protected from the corrosive process fluid by a chemically resistant plastic shell, which is typically injection molded around the magnets of the inner drive. Corrosive process fluid eventually permeates the plastic shell, thus attacking the underlying magnets. Once the corrosive process fluid has permeated the plastic coating, the shell swells causing interference between the inner drive and the containment shell and pump failure.
[0005] Therefore, what is needed is an inner drive that is more resistant to swelling once the process fluid has permeated the plastic shell.
SUMMARY OF THE INVENTION
[0006] The present invention provides a magnetic pumping element, such as an inner drive of a magnetic drive pump, that includes additional protections from corrosive process fluid. The inner drive includes a yoke with multiple magnets supported on the yoke. A protective coating surrounds at least a portion of the magnet, and in one example, extends partially over the yoke. Typically, a metallic member, such as a nickel-based alloy sleeve, is arranged proximate to the magnet. A plastic shell is arranged proximate to the sleeve. In one example, the shell completely encapsulates the yoke and magnet as a result of the molding process so that further operations, such as plastic welding, are not required to encapsulate the yoke and magnet.
[0007] A bonding material is arranged between the plastic shell and metallic sleeve, including backing rings, joining the plastic shell and metallic sleeve to one another. The bonding material prevents formation of a cavity that can become filled with the corrosive process fluid once it has permeated the shell. Additionally, the bonding material prevents the process fluid from reacting with the sleeve and from migrating between the plastic shell and the metallic sleeve/backing rings and into the joints and magnet areas
[0008] Accordingly, the present invention provides an inner drive that is more resistant to swelling once the process fluid has permeated the plastic shell.
[0009] These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a cross-sectional view schematically depicting a magnetic drive centrifugal pump assembly.
[0011] FIG. 2 is a partial cross-sectional view of an integrated impeller and inner drive assembly.
[0012] FIG. 3 is a cross-sectional view of the inner drive shown in FIG. 2 and taken along line 3 - 3 .
[0013] FIG. 4 is an enlarged view of the area indicated by circle 4 in FIG. 3 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] A magnetic drive centrifugal pump assembly 10 is schematically shown in FIG. 1 . The assembly 10 includes a motor 12 that drives a pump 14 . The motor 12 and pump 14 are supported by a frame 16 . The motor 12 includes a drive shaft 18 that is coupled to a driven shaft 20 of the pump 14 .
[0015] An outer drive 22 is supported by the driven shaft 20 . The outer drive 22 includes magnets mounted on a periphery of the outer drive for magnetically driving an inner drive 28 , which supports magnets having an opposite pole of the magnets on the outer drive 22 .
[0016] The pump 14 includes a housing 24 that supports the driven shaft 20 and outer drive 22 in a dry portion 26 of the pump 14 . A pump case 34 provides a wet portion 36 for holding the process fluid, which is separated from the dry portion 26 . The pump case 34 houses the inner drive 28 , which is coupled to an impeller 30 . The impeller 30 rotates about a stationary shaft 32 . The process fluid is pumped from an inlet 38 to an outlet 40 by the impeller 30 .
[0017] In the example shown in FIG. 2 , the inner drive 28 and impeller 30 are formed in such a way so as to provide an integral, or separable, impeller and inner drive assembly 42 . A typical inner drive 28 includes a yoke 44 that supports multiple magnets 46 about its outer periphery. The yoke 44 is typically constructed from a magnetic conductor, such as ductile iron, to absorb the magnetic flux lines behind the magnets 46 . Front and/or rear backing rings 48 are arranged on the yoke adjacent to either side of the magnets 46 . The backing rings 48 are typically constructed from a non-magnetic material such as stainless steel so that they do not interrupt the magnetic flux lines on the working side of the magnets.
[0018] A sleeve 56 is arranged radially outboard of the magnets 46 to protect the magnets 46 from process fluid. The sleeve 56 may be constructed from a nickel-based alloy such as Hastelloy or Inconel. The sleeve 56 may be a thin can that is pressed over the magnets 46 . Alternatively, the sleeve 56 may be a machined enclosure that is integral with and extends axially from one of the backing rings 48 .
[0019] A shell 60 is molded about the yoke 44 , magnets 46 , backing rings 48 and sleeve 56 to protect the components from the process fluid. The shell 60 may be constructed from a fluoroplastic such as Ethylene Tetrafluoroethylene (ETFE). Other melt processible fluoropolymers may also be used, such as Perfluoroalkoxy (PFA). The resins may also be glass or carbon fiber reinforced. Fibers in the range of 10-35%, for example, may be used, and in one example, 20%.
[0020] In the prior art, only the shell 60 and sleeve 56 protected the magnets 46 from the process fluid that permeated the shell 60 . However, increased protection from the corrosive process fluid is desired. To this end, the inventive inner drive 28 also includes a powder coating 52 arranged over the magnets 46 . The powder coating 52 may extend from one axial end of the yoke 44 to the other end of the yoke 44 providing a barrier that seals the magnets 46 relative to the yoke 44 . The powder coating 52 is arranged between the backing rings 48 and the yoke 44 , in the example shown. Referring to FIG. 3 , generous fillets 50 , currently made using potting material 54 , are provided in gaps 49 between the magnets 46 . The fillets 50 provide a smooth transition between the magnets 46 and yoke 44 , which creates a smooth, continuous coating that is free of pits and cracks. Potting material 54 , which is typically used in inner drives, fills the rest of the gaps 49 between the magnets 46 and sleeve 56 in order to prevent sleeve rupture as a result of injection molding.
[0021] One suitable powder coating is an epoxy polyester hybrid, which has a low cure temperature (250-275° F.). One example hybrid has approximately 50% epoxy and 50% polyester. The powder coating preferable has good adhesion, chip resistance, and chemical resistance. More than one coat may be desirable. The coating must withstand the molding temperatures of the shell 60 (over 600° F.). A table of the properties of examples suitable potting and powder coatings materials follows.
Property Fillet and Potting Material Powder Coating Product Name 3M epoxy 1 part adhesive 2214 HD Sherwin Williams Powdura Powder PMF Coating - Epoxy Polyester Hybrid Base Modified epoxy base Polyester (80%), epoxy (20%) Major Ingredients Epoxy resin, aluminum pigments, polyester and epoxy synthetic elastomer Adhesion ASTM D-3359 - No failure with 1/16″ squares (cross hatch) Environmental Resistance ASTM D-1002 - 1910 psi steel overlap ASTM D-B117 - passes 500 hr min shear 365 days in 100% RH salt fog test Outgassing Minimal NA Flexibility See hardness and strength data ASTM D-522 - pass on ⅛″ mandrel bend Density 1.5 g/ml Impact Resistance ASTM D-2794 - 100 lbs direct & reversed - excellent performance Viscosity >1,000,000 cps-Brookfield (paste). Powder consistency prior to oven Heated to thin for potting fill bake Hardness 85 Shore D hardness (approx) ASTM D-3363 (for thin coatings) - 2H Pencil hardness Ultimate Tensile Strength 10,000 psi Modulus of Elasticity 750,000 Coeff. of Thermal Expansion (cured) 49 × 10 − 6 in/in/C. (0-80 C.) Cure Temp or Coating Temp 2 hrs @ 225 F. cure temp 275 F. coating temp Steel T-Peel (ASTM D-1876) 50 lbs per inch of width
[0022] It has been discovered that the process fluid reacts with the sleeve 56 once it has permeated the shell 60 resulting in salts and other compounds that create a build up of solid material under the plastic shell 60 . This build up of material often results in localized swelling of the shell 60 that leads to failure of the pump 14 . Additionally, process fluid that has permeated the shell 60 may be subjected to a pumping effect by the flexing of the shell 60 . This agitation of process fluid that has permeated the shell 60 accelerates corrosion of the sleeve 56 and forces product into joints and magnet areas.
[0023] To address this problem, the inventive inner drive 28 also employs a bonding interface between the sleeve 56 and any other potentially reactive material, such as the backing rings 48 and the shell 60 . This prevents the formation of a cavity that can fill with solid material or process fluid.
[0024] The bonding interface 58 is provided by a suitable bonding material capable of joining the material of the shell 60 to the material of the sleeve 56 and/or backing rings 48 . In one example, the bonding material may be a bonding primer that is a blend of a polymeric adhesive and a fluoropolymer. The bonding primer, in one example, is stable up to 550° F. with negligible to zero out gassing. Two examples of suitable formulations are:
[0025] Formulation 1:
PelSeal PLV2100 VITON elastomer, 33% solids-13 grams PelSeal accelerator no. 4-0.5 milliliters DuPont ETFE powder 532-6210-4.5 grams
[0029] Formulation 2:
Methyl ethyl ketone-13 grams PelSeal PLV2100 VITON elastomer, 33% solids-13 grams PelSeal acceleration no. 4-0.5 milliliters DuPont ETFE powder 532-6210-4.5 grams
[0034] Formulation 2 results in a lower viscosity, and is preferably sprayed on as opposed to application by brush or pad.
[0035] The yoke 44 , magnets 46 , backing rings 48 , and sleeve 56 are typically assembled into a unit and the shell 60 molded about the unit. A typical molding process results in a void in a molding support region 62 . The molding support region 62 results from a support 64 used during the molding process that locates the unit in a desired position as the shell is molded about the unit. This void in the molding support region 62 must be filled by a secondary fusing operation, such as plastic welding. The fusing creates a boundary interface where poor bonding between the base material and weld material can exist. This frequently results in a weakened area, which can provide a premature leak path for the corrosive process fluid to enter and attack the magnets 46 .
[0036] The present invention utilizes a molding process resulting in shell 60 , fully encapsulating the unit. The support 64 , which may be multiple pins, are retracted at a desired time during the molding process so that the material forming the shell 60 fills the mold support region 62 during molding. The formulations of plastic used for the shell 60 better enable the flow fronts of material within the mold to quickly fill the molding support region once the supports 64 have retracted.
[0037] Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. In particular, the materials disclosed and their properties are exemplary only and are no way intended to limit the scope of the invention. For these and other reasons, the following claims should be studied to determine the true scope and content of this invention. | An inner drive for a magnetic drive pump includes a magnet supported on a yoke. The inner drive is driven about an axis to pump a corrosive process fluid. The magnet and yoke are fully encapsulated during the molding process to completely surround the magnet and yoke in a protective plastic shell. A sleeve is arranged radially outwardly of the magnet to provide further protection. Backing rings are arranged on either side of the magnet. A bonding material joins the plastic shell to the backing rings and sleeve to prevent a space from forming beneath the plastic shell that would become filled with the process fluid once it has permeated the plastic shell. A protective coating is arranged on at least a portion of the magnet to further insulate the magnet from the process fluid. |
This is a continuation of application Ser. No. 849,967, filed Nov. 9, 1977, now abandoned.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to the commonly owned and copending patent applications Ser. Nos. 849,968; 849,469 filed jointly herewith, whose entire disclosures are herewith fully incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a reinforcing element. More particularly this invention concerns a profiled rod or wire used as reinforcement in concrete.
A reinforcing rod or wire for use in concrete invariably has profilings or a formed surface so that the element can hold well in the concrete. It is known to form this element with a succession of distinct circumferential ribs. Another method uses a rotatable carrier on which is mounted a plurality of rollers that themselves are driven. This carrier rotates about an axis along which a rod is passed while the rollers are driven so as to form at least one generally helical groove in the element being profiled. Such an apparatus is described in the above-mentioned copending and jointly filed application by Walter Hufnagl et al.
Such rods, as shown in German Pat. Nos. 1,084,464 and 1,484,229 as well as in Austrian Pat. No. 213,363 and German published specifications Nos. 1,035,606; 1,139,352; 1,153,402 and 2,033,759 have grooves or formations of regular section throughout which are formed by uniformly shaped rollers. They do not hold well in concrete, and the tools used to make them tend to have a relatively short service life due to the type of profiling.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved reinforcing element.
Yet another object is to provide such a reinforcing element which can be made with minimal wear to the tools profiling it.
Yet another object is to provide such a reinforcing element wherein the particular characteristics of the material constituting the element are most advantageously exploited.
These objects are attained according to the present invention in an elongated reinforcing element of the above-described general type having one generally helically extending and outwardly open groove which has a predetermined width and a predetermined depth. This groove extends continuously the full length of the element at an acute angle to the longitudinal axis of the element and according to this invention the width and/or depth of the groove varies along the element.
According to further features of this invention at least two such grooves are provided, one of which may be of regular cross-sectional shape and the other of which may be of varying cross-sectional shape as described above. The element is formed between these grooves with a rib which therefore also is of varying cross-sectional shape throughout its length.
The reinforcing element made according to this invention can be produced with very little wear by the rollers forming the groove or grooves. The two grooves can be of different shape and varying cross-sections.
According to another feature of this invention the groove can be V-shaped, of semi-circular cross-section, of double semi-circular cross-section, sinuous or rounded, or formed of trapezoidal or square section.
Furthermore this reinforcing element according to the present invention is made in a machine wherein a plurality of rollers rotatable about respective roller axes are peripherally engaged with the reinforcement element and orbited around this reinforcement element as it is pulled through a head or carrier carrying these rollers. The feed rate and rotation rate are so adjusted that the grooves run at an angle between 40° and 50°, preferably 45°.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1-4 are schematic plan views illustrating portions of reinforcement elements according to this invention; and
FIGS. 1a-6a illustrate possible cross-sectional shapes of grooves according to this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIG. 1 a reinforcing element 11 a portion of whose surface is shown in flattened out condition for clarity of view has a first helically extending groove 1 that lies at an angle of approximately 45° to the longitudinal axis of the element 11. Another groove 3 of identical and regular cross-section is separated from the groove 1 by ribs 5 also of regular cross-sectional shape. The element 11 is further formed with a groove 2 having periodically raised formations or lands 4 that give this groove 2 a varying cross-sectional shape. Such an element 11 is formed in a machine as described above in the above-cited copending application by means of three rolls carried on a rotatable carrier and themselves rotatable about respective axes.
FIG. 2 shows an element 11a having two grooves 1a identical to the grooves 1 and 3 of FIG. 1 and separated by regular-section ridges 5a, and with a groove 7 of sinusoidal shape and forming a ridge 8 of similarly sinusoidal shape.
It is also possible to form an element 11b as shown in FIG. 3 with two sinusoidal-shaped grooves 9 and 10 and a single regular-section groove 1c.
FIG. 4 shows an arrangement wherein all of the grooves 12 are of sinusoidal shape on both sides and flank ridges 13 of similarly sinusoidal shape. In this arrangement the element 11c therefore has grooves which vary with respect to depth rather than with respect to width.
FIG. 1a shows how the groove may be of rectangular section. In FIG. 2a the groove is generally V-shaped but has a rounded root. The groove of FIG. 3a is of semi-circular section.
It is also possible as shown in FIG. 4a to form the groove of generally square section but with a semi-circular recess in the bottom. A semi-circular boss could also be provided in the bottom of the square-section groove as shown in FIG. 6a.
FIG. 5a shows generally V-shaped groove with a wide root and a semi-circular boss in this space. All of these formations are made by rollers and any of the corners may be rounded or straight if desired. It is possible for the width as well as the length of the groove to vary, and for the groove to change cross-sectional shape from one region to another. Appropriate profiling of the respective forming roll makes this possible.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of structures differing from the types described above.
While the invention has been illustrated and described as embodied in a reinforcing element, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims. | A reinforcing rod or wire is formed with a plurality of helical and longitudinally continuous grooves. At least one of these grooves is of varying width and/or depth, and similarly may have a varying cross-sectional shape. |
BACKGROUND INFORMATION
[0001] The present invention relates to magnetic hard disk drives. More specifically, the present invention relates to a system for an improved magnetic head arm assembly (HAA).
[0002] Among the better known data storage devices are magnetic disk drives of the type in which a magnetic head slider assembly floats on an air bearing at the surface of a rotating magnetic disk. Such disk drives are often called ‘Winchester’-type drives. In these, one or more rigid magnetic disks are located within a sealed chamber together with one or more magnetic head slider assemblies. The slider assemblies may be positioned at one or both sides of the magnetic disks.
[0003] Typically, each magnetic head slider assembly in magnetic disk drives of the type referred to is coupled to the outer end of an arm or load beam. FIG. 1 provides a perspective view of a typical magnetic head arm (HAA) assembly 108 . The slider 102 is mounted in a manner which permits gimbaled movement at the free outer end of the suspension 106 such that an air bearing between the slider assembly 102 and the surface of the magnetic disk can be established and maintained. The elongated suspension 106 is coupled to an appropriate mechanism, such as a voice-coil motor (VCM) (not shown), for moving the suspension 106 across the surface of the disk (not shown) so that a magnetic head contained within the slider 102 can address specific concentric data tracks on the disk for writing information on to or reading information from the data tracks.
[0004] In order to achieve a quick response ability, a focus has been placed on reducing the weight (and thus, the inertial effects) of the HAA 108 . A typical means of achieving this has been to reduce the thickness 110 of the HAA 108 . To prevent HAA 108 operational flexure (and thus, poor tracking) and/or unintentional deformation during the assembly processes, rib elements 112 are utilized (such as in U.S. Pat. No. 5,313,353 of Kohso et al.). The rib elements 112 reduce the tendency of the HAA 108 to flex towards and away from the disk surface.
[0005] Problems with this design 108 include the complexity of design and difficulty of manufacture. Many complex cutting and bending processes must be performed to produce this HAA baseplate 108 . This greatly affects quality control as well as cost of production. It is therefore desirable to have a system and method for an improved magnetic head arm assembly (HAA) that avoids the above-mentioned problems, in addition to other advantages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] [0006]FIG. 1 provides a perspective view of a typical magnetic head arm assembly (HAA).
[0007] [0007]FIG. 2 illustrates Head Arm Assembly (HAA) design and assembly according to an embodiment of the present invention.
[0008] [0008]FIG. 3 provides a cross-section view of the coupling between the unimount suspension arm and the flexure/load beam assembly under principles of the present invention.
DETAILED DESCRIPTION
[0009] [0009]FIG. 2 illustrates Head Arm Assembly (HAA) design and assembly according to an embodiment of the present invention. In this embodiment, an HAA structure 206 includes a flexure/load beam assembly 202 and a unimount suspension arm 204 . The suspension arm 204 is formed from a uniform piece of material. In one embodiment the suspension arm is made from a material that has a high Young's Modulus(Y)-to-density(D) ratio, such as Aluminum with Y/D=110 Mpsi/(lb/in 3 ) (Y=11 Mpsi (megapounds per square inch) and D=0.10 lb/in 3 (pounds per cubic inch)) or Titanium with Y/D=106 Mpsi/(lb/in 3 ) (Y=17 Mpsi and D=0.16 lb/in 3 ). In an embodiment, the suspension arm 204 is of a material having a Y/D of at least 100 Mpsi/(lb/in 3 ).
[0010] In one embodiment of the present invention, the suspension arm 204 has a thickness 214 of at least 0.7 millimeters (mm), and in one embodiment, the thickness of the suspension arm 204 is 0.8 mm. Further, in an embodiment, the thickness is at least 2.5% the length 211 of the HAA 206 (axis of rotation to magnetic head). For example, a 2.5 inch hard disk drive (HDD), having a 28.5 mm length HAA 206 , in one embodiment of the invention has a suspension arm thickness 214 of at least 0.7 mm (2.5% the length).
[0011] In one embodiment, the unimount suspension arm 204 is coupled to the flexure/load beam assembly 202 to form the HAA 206 . In an embodiment, the coupling is performed by laser welding overlapping portions 208 of the two components 202 , 204 . In an alternative embodiment, thermosetting epoxy is utilized to couple the two components 202 , 204 . In an embodiment, alignment holes 210 are utilized to accurately position the components 202 , 204 upon one another.
[0012] [0012]FIG. 3 provides a cross-section view of the coupling between the unimount suspension arm 302 and the flexure/load beam assembly 304 under principles of the present invention. As stated above, in one embodiment laser welding 306 is utilized to join the two components 302 , 304 . In one embodiment, spot welds are performed at several locations 306 (See also FIG. 2).
[0013] Although several embodiments are specifically illustrated and described herein, it will be appreciated that modifications and variations of the present invention are covered by the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention. | A system and method for an improved magnetic head arm assembly (HAA), reducing complexity of design and difficulty of manufacture, is disclosed. |
This invention relates to a novel head band specifically designed for use on premature babies, for the mounting of nasal cannulas and opposite oxygen feed tubes thereof.
PRIOR ART
While no relevant prior art was located in a preliminary patentability novelty search that was conducted in Class 128, sub-classes 207.17, 107.18 912, and DIG. 26, patents of mere interest are as follow: U.S. Pat. No. 4,665,566 granted May 19, 1987 to Garrow relating to a headband directed to a substantially common usage to that of the present invention, in mounting of dual spaced-apart nasal oxygen cannulas, but differing in material ways from the present invention; U.S. Pat. No. 4,774,946 granted Oct. 4, 1988 to Ackerman relating likewise to a substantially common head cap usage as that of the present invention, in the mounting of dual spaced-apart nasal oxygen cannulas.
BACKGROUND TO THE INVENTION
Premature babies typically are arching and irritable, not getting adequate rest because of the constant necessity to refit cannula prongs into the nares of the nostrils. It is clearly desirable that the prongs, once finally correctly inserted and positioned, not require future repositioning that often results from slippage and/or shifting with inadequate and/or unstable securing of the oxygen-providing tubes normally placed/mounted on opposite sides of the head.
The present inventor, having been impressed with the commercialized headband disclosed by the above-noted Ackerman patent, became frustrated with the securing mechanism thereof--finding that the premature babies characteristically being writhing, restless and twisting beings, quickly and repeatedly caused the spaced-apart oxygen-providing tubes to pull-out from the laterally-positioned mounting u-shaped members--with the result that the critically required oxygen needed on a constant basis of delivery through the cannulas supported by the tubes was not meeting or even approaching minimum requirements of the patient premature-babies. While redundant to so state, it should be apparent that the stable and secure mounting of the two spaced-apart oxygen-providing tubes is directed to the sole or at-least dominant support-purpose for maintaining the cannulas in an inserted state within the nostrils of a premature baby. The cap-like headband slips and slides and/or falls off of the squirming premature babies, resulting in disengagement from and/or incorrectly positioning of the cannulas in the nostrils. It is for this reason that the present invention came into being. While the above-noted Ackerman band and tube and cannulas support might well be satisfactory for a sedimentary non-moving normal non-premature baby or child, such is not the case for the premature babies to which the present invention is directed and has been successfully tested in actual ward use on numerous premature babies. In the hospital wards, attempts have also been made to anchor the spaced-apart oxygen tubes by binding them between opposing strips of material having detachably mateable hooks and loops, of the nature described in the Garrow patent, but with the poor results of the mated-latching thereof being promptly or quickly pulled-apart as a result of the wiggling, squirming and/or writhing of the premature babies having cannulas mounted in their nostrils--with the cannulas according usually quickly falling from and/or being inoperatively repositioned in the nostrils. The hat carrying the loops and hooks arrangements were too loose and the hat did not maintain its shape. Also tube strips thereof come off, releasing the tube(s). Also, extensive efforts have been made by ward nurses and/or attendants to use various combinations of adhesive tape strips, with repeated failures thereof to effectuate any lasting holding and/or supporting of the spaced-apart oxygen-providing tubes and/or the support of the cannulas in fixed proper positioning within the nostrils of the premature baby. In despiration attempts to stabilize and prevent loosening of the support for the oxygen-providing tubes and nasal cannulas supported thereby, the attending staff, tending to the premature babies, turned to use of pins and elastic bands to secure the tubing--together with the accompanying hazard of pins accidentially opening in the vicinity of the infant's eyes or otherwise puncturing the skin. Other persons have attempted to wrap gauze around the premature infant's head together with the anchoring thereof with pins and/or adhesive, elastic bands and the like, all with equal unsatisfactory and/or failing results.
OBJECTS OF THE INVENTION
Accordingly, objects of the present invention include the overcoming of difficulties and problems above-discussed in the maintaining of sturdy and lasting intermittent attachment and support of oxygen-providing tube(s) and nasal cannulas supported thereby within the nostrils of premature babies, with a resultant loss of life and/or avoidance of brain or other cellular damage otherwise arising from a shortage of oxygen. While elastic banded headbands have been used in certain instances, the tightness thereof is dangerous to the pliable underdeveloped heads of premature babies, together with potentially further cutting-off desired and/or essential blood circulation (and oxygen content thereof) to vital head parts; and together with the realistic possibility of disfiguring the tender and underdeveloped heads of such premature babies.
Another particular object is to provide a novel headband that is not readily subject to slip-off of the head of a baby on which it is mounted in the support of oxygen-providing tubes that support nasal cannulas within the nostrils of a premature baby.
Another object is to provide a novel headband devoid of potential damage to the circulation and/or pliable form of the head of a premature infant baby, when mounted thereon.
Another object is to obtain a headband for sturdy mounting of oxygen-providing tubes and resulting support of nasal-inserted cannulas, while achieving simplicity of intermittent securing of oxygen-providing tubes and nasal cannulas supported thereby.
Another object is to obtain a headband of simple and inexpensive structure adapted for sturdy intermittent mounting and support of oxygen-providing tubes that support nasal cannulas.
Another object is to obtain a headband adaptable to easy and quick intermittent mounting and dismounting from the head of a premature baby, for the secure supporting of oxygen-providing tubes that support nasal cannulas.
Another object is to provide a novel support for oxygen-providing tubes utilized to support nasal cannulas for premature babies, while concurrently leaving ample free space facilitating better and/or improved access for peripheral IVs, arterial lines and percutaneous lines.
Other objects become apparent from the preceding and following disclosure.
BROAD DESCRIPTION
Broadly the invention may be described as a premature baby headband device for supporting nasal cannulas and opposite air and/or oxygen tubes, comprises a combination, as follows. Headband structure(s) and mechanism(s) thereof have a longitudinal length for exerting a predetermined degree of stretchable and retractable elasticity. The headband and mechanism thereof include first and second mateable securing means. The headband structure(s) and mechanism thereof include an elongated substantially flat-faced band having opposite first and second ends. The first end mounts the first mateable securing structure(s) and mechanism thereof. The second end mounts the second mateable securing structure(s) and mechanism thereof. The first and second mateable securing structure(s) and mechanism(s) thereof are intermittently alternately securable to and releasable from one-another. The first and second securing structure(s) and mechanism(s) have alternately available positions for securing the above-noted opposite first and second ends and for securing and releasing the above-noted first and second ends alternately at the alternately available positions. The headband has at-least a minor amount of flexibility for resilient alternate stretch and retraction during mounting of the headband on and circumscribingly around an upper head and forehead of a premature patient child. The headband has an elongated axis along the longitudinal length. There are stretch-limiting structure(s) and mechanism thereof having an elongated shape for mounting along said longitudinal length. The stretch-limiting structure(s) and mechanisms thereof are mounted on and secured to said headband at multiple points along the longitudinal shape and the longitudinal length such that the stretch-limiting means is further for preventing the headband means from excessive stretching beyond a predetermined degree and amount of permissive stretching along said longitudinal length, thereby excessive band tightness during band resilient retraction is avoided when mounted on a baby's head. Additionally there are nasal-cannulas oxygen tubes-securing structure(s) and mechanism thereof for intermittent securing and releasing each of at-least two spaced-apart oxygen-providing tubes connected to the nasal cannulas. The nasal cannulas oxygen tubes-securing structure(s) and mechanism thereof is/are mounted on the headband structure(s) and mechanism thereof.
In an alternate second broad embodiment, the premature baby headband device for supporting nasal cannulas and opposite air and/or oxygen tubes, as a combination may be described as follows. There are annular headband structure(s) and mechanism thereof for fitting downwardly circumscribingly around and upon a premature baby's head. The headband structure(s) and mechanism thereof have a longitudinal length for exerting a predetermined degree of stretchable and retractable elasticity. The headband includes an elongated substantially flat-faced band or strip that has at-least a minor amount of flexibility for resilient alternate stretch and retraction during mounting of the annular headband on and circumscribingly around an upper head and forehead of a premature patient child. The headband has an elongated axis along said longitudinal length. There is stretch-limiting structure and mechanism thereof having an elongated shape for mounting along the longitudinal length. The stretch-limiting structure(s) and mechanism thereof are mounted on and secured to the headband at multiple points along the longitudinal shape and the longitudinal length such that the stretch-limiting means is further for preventing the headband means from excessive stretching beyond a predetermined degree and amount of permissive stretching along the longitudinal length. Thereby excessive band tightness during band resilient retraction is avoided when mounted on a premature baby's head. And nasal cannulas oxygen tubes-securing structure(s) and mechanism are provided for intermittent securing and releasing each of at least two spaced-apart oxygen-providing tubes connected to the nasal cannulas. The nasal cannulas oxygen tubes-securing structure(s) and mechanism thereof is/are mounted on the headband structure(s) and mechanism thereof.
In a first preferred embodiment on each of the above-described alternate broad statements of the invention, the structure and mechanism thereof that secure the nasal cannulas oxygen and/or air-providing tubes include at least two spaced-apart tying structure(s) and mechanism thereof. At least one of the tying structure(s) and mechanism thereof includes loose-ends of predetermined lengths sufficient for the loose ends to jointly envelope and be tied-together to secure at least that one of the normally two spaced-apart oxygen-providing tubes, preferably securing both. One of the spaced-apart tying structure(s) and mechanism thereof is positioned to be mounted adjacent one side of a baby's head and a remaining other one of the spaced-apart tying structure(s) and mechanism thereof is positioned on an opposite other side of a baby's head, when the headband structure(s) and mechanism thereof are mounted on a premature baby's head.
In a second preferred embodiment as an improvement on the above-described first preferred embodiment, each of the above-noted loose-ends includes an elongated ribbon-shaped composition adapted for two of the elongated ribbon-shaped compositions to be tied together for each pair or set of above-noted loose-end, when a set of loose-ends is jointly enveloping one of the two spaced-apart oxygen-providing tubes.
In a third preferred embodiment as an improvement on the above-described second preferred embodiment, the stretch-limiting structure(s) and mechanism thereof include a plurality of serially-positioned end-to-end strips of the elongated composition. The loose-ends are end-portions of the end-to-end strips. The stretch-limiting structure(s) and mechanism thereof include the nasal cannulas oxygen-providing tubes-securing structure(s) and mechanism thereof.
In a fourth preferred embodiment as an improvement on the third preferred embodiment, the stretch-limiting structure(s) and mechanism thereof consist essentially of close-knitted elongated ribbon-like strips.
In a fifth preferred embodiment as an improvement on the fourth preferred embodiment, the headband structure(s) and mechanism thereof comprise elastic ace-bandage.
In a sixth preferred embodiment as an improvement on the fourth preferred embodiment, the headband structure(s) and mechanism thereof includes laminated elastic bandage laminated by an intermediate binding composition.
In a seventh preferred embodiment as an improvement on the sixth preferred embodiment, the intermediate binding composition comprises latex composition.
In an eighth preferred embodiment as an improvement on the eighth preferred embodiment, the loose-ends each range in length from about 7 centimeters to about 20 centimenters in length, and each have a width ranging from about 0.6 centimeter to about 2 centimeters.
In a ninth preferred embodiment as an improvement on the ninth preferred embodiment, the loose-ends each range in length from about 10 centimeters to about 15 centimeters in length, and each have a width ranging from about 1 centimeter up to about 1.5 centimeters.
In a tenth preferred embodiment as an improvement on the ninth preferred embodiment, the headband means ranges in length from about 18 centimeters to about 45 centimeters.
In an eleventh preferred embodiment as an improvement on the tenth preferred embodiment, the headband means ranges in length from about 21 centimeters to about 24 centimeters.
In a twelfth preferred embodiment as an improvement on the eleventh preferred embodiment, the headband means ranges in length from about 25 centimeters to about 28 centimeters.
In a thirteenth preferred embodiment as an improvement on the twelfth preferred embodiment, the headband means ranges in length from about 29 centimeters to about 32 centimeters.
In a fourteenth preferred embodiment as an improvement on the thirteenth preferred embodiment, the headband means ranges in length from about 33 centimeters to about 36 centimeters.
In a fifteenth preferred embodiment as an improvement on the fourteenth preferred embodiment, the headband means ranges in length from about 37 centimeters to about 40 centimeters.
In a sixteenth preferred embodiment as an improvement on each of the above-described alternate statements of the broad invention, the stretch-limiting structure(s) and mechanism thereof consist essentially of close-knitted elongated ribbon-like strips.
In a seventeenth preferred embodiment as an improvement on each of the above-described alternate statements of the broad invention, the headband structure(s) and mechanism thereof comprise elastic bandage.
In an eighteenth preferred embodiment as an improvement on the first above-described broad invention, the headband structure(s) and mechanism thereof includes laminated elastic bandage laminated by an intermediate binding composition.
In a nineteenth preferred embodiment as an improvement on the eighteenth preferred embodiment, the intermediate binding composition comprises latex composition.
In a twentieth preferred embodiment as an improvement on the first preferred embodiment, the loose-ends each range in length from about 7 centimeters to about 20 centimeters in length, and each have a width ranging from about 0.6 centimeter to about 2 centimeters.
In a twenty-first preferred embodiment as an improvement on the first preferred embodiment, the loose-ends each range in length from about 10 centimeters to about 15 centimeters in length, and each have width ranging from about 1 centimeter up to about 1.5 centimeters.
In a twenty-second preferred embodiment as an improvement on above-described first broad invention, the headband structure(s) and mechanism thereof range in length from about 18 centimeters to about 45 centimeters.
In a twenty-third preferred embodiment as an improvement on the above-described first broad invention, the headband structure(s) and mechanism thereof ranges in length from about 21 centimeters to about 24 centimeters.
In a twenty-fourth preferred embodiment as an improvement on the above-described first broad invention, the headband structure(s) and mechanism thereof range in length from about 25 centimeters to about 28 centimeters.
In a twenty-fifth preferred embodiment as an improvement on the above-described first broad invention, the headband structure(s) and mechanism thereof range in length from about 29 centimeters to about 32 centimeters.
In a twenty-sixth preferred embodiment as an improvement on the above-described first broad invention, the headband structure(s) and mechanism thereof range in length from about 33 centimeters to about 36 centimeters.
In a twenty-seventh preferred embodiment as an improvement on the above-described first broad invention, the headband structure(s) and mechanism thereof range in length from about 37 centimeters to about 40 centimeters.
In a twenty-eighth preferred embodiment of the invention as an improvement on the above-described alternate second broad invention, the annular headband structure(s) and mechanism(s) thereof have an inner circumference ranging from about 18 centimeters to about 45 centimeters.
In another alternate, third broad embodiment, for supporting nasal cannulas and opposite air and/or oxygen tubes, the combination comprises headband structure and mechanism thereof having an elongated dimension and along the elongated dimension having a predetermined degree of stretchable and retractable elasticity. The headband structure in the form of a substantially flat-faced band has at least a minor amount of flexibility for resilient alternate stretch and retraction during mounting of thereof on and circumscribingly around an upper head and forehead of a premature patient child. The elongated dimension has an elongated axis. Stretch-limiting structure and mechanism of elongated shape for mounting along the longitudinal length, are mounted on and secured to the headband structure at multiple points along said longitudinal shape and said longitudinal length such that said stretch-limiting structure and mechanism are further for preventing the headband structure from excessive stretching beyond a predetermined degree and amount of permissive stretching along said longitudinal length whereby excessive band tightness during band resilient retraction is avoided when mounted on a baby's head, and nasal cannulas oxygen tubes-securing structure and mechanism thereof for intermittent securing and releasing each of at least two spaced-apart oxygen-providing tubes connected to nasal cannulas. Cannulas air and/or oxygen tubes-securing structure mountable on the headband structure.
In a twenty-ninth preferred embodiment as an improvement on the generic and third broadly-stated invention, the headband is annular headband structure and has an inner circumference ranging from about 21 centimeters to about 24 centimeters.
In a thirtieth preferred embodiment as an improvement on the generic and third broadly-stated invention, the headband is annular and has an inner circumference ranging from about 25 centimeters to about 28 centimeters.
In a thirty-first preferred embodiment as an improvement on the third broadly embodiment, an annular headband has an inner circumference from about 29 centimeters to about 32 centimeters.
In a thirty-second preferred embodiment as an improvement on the third broad embodiment, an annular headband has an inner circumference from about 33 centimeters to about 36 centimeters.
In a thirty-third preferred embodiment as an improvement on the generic and fourth broadly-stated invention, the headband is annular and has an inner circumference ranging from about 37 centimeters to about 40 centimeters.
The invention may be better understood by making reference to the following figures.
THE FIGURES
FIG. 1 diagrammatically illustrates a top plan view of the headband device above-described of this invention in a preferred embodiment thereof, with partial cut-away for improved explanation and description, the bottom face appearing the same as the upper face except for the tie-ribbon strips arising from the top face thereof, which normally would constitute the outer-facing face or surface thereof when mounted on a baby's head.
FIG. 2 diagrammatically illustrates a cross-sectional view of the embodiment of FIG. 1, taken along lines 2--2 of FIG. 1, illustrating the laminated layers and stitching and bottom end with mounted (layered) hook-like securing mounting layer and hook-elements arising therefrom.
FIG. 3 diagrammatically illustrates an annular headband embodiment of the invention, in a front and top perspective view thereof, having the same laminated layer construction and composition as that illustrated in FIG. 2.
FIG. 4 illustrates the device connected to nasal tubes in position on an infant's head.
DETAILED DESCRIPTION
FIGS. 1 and 2 illustrate a common preferred embodiment of the invention and accordingly exhibit correspondingly identical indicia where there is repetition. FIG. 3, illustrating a variation as an annular preferred embodiment, nevertheless otherwise has the same basic construction of laminated parts and compositions and stitching and ribbon strips and the like, and accordingly have correspondingly related indicia for elements corresponding to those to be hereinbelow described for FIGS. 1 and 2.
Accordingly, FIG. 1 diagrammatically illustrates the lineally-extending embodiment of the headband device 4 of this invention that in use is mounted around the head at the forehead level the same position as is aptly illustrated in each of the above-discussed prior art U.S. Pat. Nos. 4,665,566 to Garrow and 4,774,946 to Ackerman--both patents being herewith incorporated by reference into this disclosure as if fully repeated herein, such positioning being illustrated in FIG. 4.
For the device 4, there is shown the upper face 5a of elastic elongated laminated band 4a having elongated longitudinal axis 4a'. Mounted on one end of that upper face is the loop-elements fabric having female loop elements 6a' extending outwardly therefrom as shown, being concurrently stitched by the same cross-stitchings typically represented by stitching 24c that serves in-part to secure a portion of the ribbon-like strip 8g. The upper surface 5a has a pair of spaced-apart aligned openings 7a and 7b about mid-point of the width thereof as a part of the tying structure at one end of the upper face 5a, and has a second pair of spaced-apart aligned openings 7c and 7d about mid-point of the width as also apart of the tying structure at an opposite end of the upper face 5a. Loose or free tying strip ribbon-end 8a exits through the opening 7a in the upper face at one end, as does the loose tying strip ribbon-end 8b through the opening 7b. Likewise the tying strip 8d exits from opening 7d and tying strip 8e exits from opening 7c of the upper face 5a. Throughout the elastic elongated laminated band 4a is positioned the loosely-laid (not under elongated stretch-stress) serially consecutively aligned non-elastic ribbon-like strips 8 having continuous (integral) therewith the above-identified loose ends 8a, 8b, 8d and 8e. The non-elastic ribbon-like strips 8 are intermittently anchored by cross-stitching 14a, 14b and the like anchoring the ribbon-like strips 8 to the elongated laminated band 4a. In the cut-away of FIG. 1, there are viewable on opposite sides of one of the non-elastic ribbon-like strips 8, the laminating latex 9a and 9b (typically) binding together the upper face 5a and the lower face 5 b (see FIG. 2), which are also held in the laminated state by typically elastic thread or non-elastic thread loosely-woven, identified as stitching 15a and 15b extending along and adjacent opposite edges that extend along the elongated longitudinal axis 4a' of the elastic elongated laminated band 4a. The loosely lying non-elastic ribbon-like strips 8 intermittently stitched by stitching 14a and 14b and the like permit stretching of the elastic and thereby resilient elongated laminated band 4a. The elastic elongated laminated band 4a is thus stretchable when mounting on a baby's head at about forehead level, but the extent to which it can be stretched is limited by the non-elastic loosely-lying ribbon-like strips 8 restraining amount of stretching of the elastic elongated laminated band 4a by virtue of the intermittent stitching through the ribbon-like strips 8 and through the elongated ribbon-like strips 8. The loose tying ends 8a, 8b, 8d and 8e each have lengths 10 and widths 8e. Likewise the non-elastic loosely lying ribbon-like strips 8 have the same width 8e, in this preferred embodiment. The elongated device 4 and elastic band 4a have a length 11, and a width 12.
FIG. 2 illustrates the FIG. 1 embodiment as taken in cross-section along lines 2--2, showing the state of lamination of the elastic elongated laminated band 4a through the upper and lower surfaces (layers) 5a and 5b laminated together by latex layer 9a and 9b on each of opposite sides of the illustrated one of the non-elastic loosely lying ribbon-like strips 8. The laminated upper and lower surfaces and latex binder-layer 9a are further sewn together by the afore-stated stitching 15a and 15b. Also stitching 15a and 15b at the end-positioned securing hook elements fabric 16b having its male hook elements 16b' that intermittently interlock with the female hook elements 16a' when overlapped during the mounting of the headband device 4 onto the head of a premature baby.
FIG. 3 diagrammatically illustrates in perspective with partial cut-away an annular headband device of the invention, otherwise identical in the make-up of the laminated band of upper and lower faces (layers) 5'a and 5'b and and ribbon-like strips 8' and the latex binder 9'a and 9'b and the loose typing ends 8'a, 8'b, 8'd and 8'e, and the intermittent stitchings 14'a, 14'b, 14'c, 14'd and the like. The basic difference in this embodiment is that no overlapping ends nor end-securing structures (loops and hooks) are required, yet in this embodiment, minor limited stretching is possible to enable the mounting of an annular headband embodiment of the invention having the approximate same dimensions as the circumference of the head of the baby-patient.
While with the embodiment of FIG. 1 various lengths have to be alternately available for use of children of different head sizes--this being particularly true for the headband devices of this invention because of the greatly restricted permissible stretching in order to avoid excessive retraction (resiliency-return) pressure on the tissues and tender or soft skull of a premature baby, likewise to a possibly greater extent the annular band device embodiment requires even more careful sizing or measuring and matching approximate sizes with approximate baby head diameter, to obtain optimal and most safe results.
Consistent with the objects of the invention, the above-described embodiments as claimed hereinafter, make possible better scalp access and observation for peripheral IVs, arterial lines and percutaneous lines.
Normally in the implementing of use of the embodiment of typically that of FIGS. 1 and 2, for example, the following procedure is followed. Choose the size needed by measuring the baby's head circumference. Thereafter place the headband device around the baby's head as if measuring circumference, and position the oppositely-located ties at temporal areas. Fasten the headband device snugly with the hook and loop overlapping securing-fasteners. Place prongs in the nares and adjust the angle of the circuit tubing to line up with the ties. Then tie the ties tightly around the tubing. Continuous positive airway pressure delivery of oxygen and/or air is now secure. The prongs and tubing will move with the baby whether repositioning the baby or with baby movement. Best positioning, for enhancing neurodevelopment or for achieving optimal pulmonary function, can be realized with this inventive device. When moving a baby in or out of an isolette and/or changing to intermittent use of nasal cannula administration, the attendant leaves the headband device in place; merely untie the ties, move the baby and retie the ties around the circuit tubing and/or nasal cannula.
The above-described construction with its limited minor degree of permissible stretching, with the initial conforming the fit to the infant's scalp dimensions, remains consistant and constant in its limiting of the maximum elasticity of the material of the band and the stretch limiting structure above-discussed and the intermittently stitched ribbon-like strips 8. The fit remains snug, but not harmfully restrictive. The material and construction creates surface tension on the infant's skin, avoiding slipping out of position, but devoid of any substantial risk of excessive elastic-contraction nor of excessive pressure therefrom. The amount of latex is held to a minimum and the elastic fabric of the band is normally a breathable weave that helps to ensure skin integrity and to avoid eventual irritations of the skin.
While male hook-elements and female loop-elements have been illustrated and discussed, it is within the scope and skill of the art to utilize other equivalent fastening means, including tying strings or ribbons, snaps, buttons and the like.
Not only does the inventive device add improved treatment to the premature baby, but by doing so the treated child has longer periods of uninterrupted rest and less nursing time is spent readjusting prongs that heretofore have notoreously slipped-out of the proper positioning and/or nasal cavities to become ineffectual medically or therapeutically. The simplicity of applying the inventive headband device of any illustrated embodiment, facilitates the speedy and proper and frequent use when needed of these devices to the ultimate further and improved benefits of the suffering premature baby's--readily and realistically potentially saving the lives of many premature babies and/or preventing brain or other damage because of lack of adequate oxygen otherwise.
Likewise, it is within the scope of the invention to make any and/or other modifications and/or substitution of equivalents and/or variations within the skill of an artisan of ordinary skill in this particular art. | A premature baby elastic strip-like headband having expansion limiting structure with opposite ends of which one end has male hook-like multiple alternate attaching elements and of which a remaining opposite end has female loop-like attaching elements detachably securable to one-another at optionally alternate locations thereof, and having nasal cannulas oxygen tubes-securing structures positioned and mounted on the headband such that the nasal cannulas oxygen tubes are located on opposite side of a baby's head the headband is mounted thereof. |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S. patent application Ser. No. 61/654,628, filed Jun. 1, 2012 which is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The subject matter disclosed herein relates to input ac voltage regulation and power flow control of bi-directional AC-DC power converters and bi-directional AC-AC converters.
[0004] 2. Description of Related Art
[0005] The increasing awareness of climate change has prompted many governments worldwide to impose policies that call for the introduction of renewable energy sources. Presently power generation is “centralized” and “unidirectional,” By monitoring the voltage and frequencies of the power grid, the utility companies can determine the amount of electricity needed by the load centers (such as a city) and can generate the required amount of electric power from the power plants. A balance of power generation and load is an essential condition for the stability of the power system. Although the difference between power generation and load demand can be absorbed by energy storage, energy storage is either expensive (such as batteries) or dependent on locations (such as water reservoirs). For existing power systems, the control paradigm is to have “the power generation follow the load demand” in order to maintain power system stability.
[0006] In future power grids, renewable energy sources such as solar panels and wind power generators will be installed in a “distributed” manner and the power flow could be “bidirectional,” i.e., the power can be supplied to the grid from these generators or taken from the grid by these generators. These distributed renewable power sources, both known or unknown to the utility companies, make it very difficult for the power companies to control the power balance. Therefore, there is a need for a shift of the control paradigm for a future power grid with substantial penetration of intermittent renewable energy. In the new paradigm “the load demand has to follow power generation.”
[0007] In order to achieve power balance, various methods have been proposed previously. Scheduled load shedding has been a traditional method in load power control. However, such a method is not useful for maintaining dynamic power balance in real-time. Smart loads with ON/OFF control for electric loads, such as refrigerators and air-conditioning systems [1-3], have been proposed for real-time power balance. See, the articles [1] S. C. Lee et al., “Demand Side Management With Air Conditioner Loads Based on the Queuing System Model,” IEEE Transactions on Power Systems, Volume: 26, Issue: 2, 2011, pages 661-668; [2] G. C. Heffner et al., “Innovative approaches to verifying demand response of water heater load control,” IEEE Transactions on Power Delivery, Volume: 21, Issue: 1, 2006, pages 388-397; and [3] A. Brooks et al., “Demand Dispatch,” IEEE Power and Energy Magazine, Volume: 8, Issue: 3, 2010, pages 20-29. However, shutting down electrical appliances is intrusive and may cause inconvenience to and opposition from consumers.
[0008] Recently, an electric spring concept based on the three centuries old Hooke's law has been proposed and practically embedded in electric loads to regulate the line or mains voltage in the power grid. See, [4] S. Y. R. Hui et al., “Power Control Circuit and Method for Stabilizing a Power Supply,” U.S. patent application Ser. No. 61/389,489, filed on 4 Oct. 2010 (Patent Application Publication No. US2012/0080420 A1). The electric spring concept refers to the use of a power converter together with its load to form a “smart load” unit that can provide regulation of the mains voltage. With the use of an input voltage control (instead of the traditional output voltage control), reactive power converters (i.e. power converters that handle reactive power only and not active power) have been used to fulfill the electric spring concept. The electric spring implementation based on the use of a controlled voltage source connected in series with an electric load is described in the above-identified Hui article and is shown in FIG. 1 . The controlled voltage source can be realized with a reactive power converter. The power converter can be a power inverter in which a large capacitor C dc is used as a controllable dc voltage source (V dc ) as shown in FIG. 2 . The power inverter can then be switched in a sinusoidal pulse-width modulated (PWM) manner to generate a switched PWM voltage waveform with a strong fundamental voltage and some high-frequency voltage harmonics. The high-frequency voltage harmonics are filtered by the inductive-capacitive (LC) filter so that only the sinusoidal fundamental voltage (V a ) is generated across the capacitor of the LC filter as the voltage output of the electric spring. It should be noted that in the control scheme shown in FIG. 2 the electric spring uses “input voltage control.” The control variable is the input voltage of the reactive power converter, which is the mains voltage (V s ) at the location of the installation of the equipment. The output voltage of the reactive power control (V o ) is allowed to fluctuate for the regulation of the mains voltage V s . In order to ensure that the power converter works as a reactive power controller, the vector relationship of V a and I o is perpendicular when Io is not zero as shown in FIG. 4 .
[0009] The International Electrotechnical Commission Regulation IEC 61000-3-2 requires offline electric equipment of 20 W or above to comply with electromagnetic compatibility requirements. For equipment fed by ac mains, the input power factor must be kept at or above 0.9. In modem electric equipment such as switched mode power supplies for computers and servers, power factor corrected (PFC) ac-dc power converters are commonly used to ensure that the input voltage and input current are in phase (i.e. unity power factor if the input current is sinusoidally shaped). In this regard, the power inverters (half-bridge or full-bridge inverters in FIG. 3 ) can be used as ac-dc power converters as shown in FIG. 5 .
[0010] In existing ac-dc power conversion applications, it is always assumed that the mains voltage is sinusoidal and stable at its nominal rms value (such as 230V), because most developed countries have well regulated mains voltage that is kept to its nominal value with a +/−6% tolerance in developed countries and +/−10% in other regions. Therefore, traditional ac-dc power converters normally assume a fairly stable ac mains supply. For this reason, no input-voltage control (except that in the Hui et al. article and application, which is by the present inventors) has been reported. Traditional ac-dc power converters adopt the “output-voltage control” because they are used for regulating the output dc voltage. For the power factor corrected (PFC) converters in FIG. 5 , the mains voltage is sensed so that the power converter can be switched to force the input current of the power converter to follow the sinusoidal shape of the mains voltage and be in phase with the mains voltage. In this way, near unity power factor can be achieved. The magnitude of the input current is controlled to maintain a fairly constant output de voltage (Vdc) through an “output-voltage control” feedback loop. For a 220V-240V rms mains supply, typical Vdc is controlled at a dc voltage of about 400V. Because the input voltage and current of this PFC converter are in phase, the PFC power converter with its output load emulates a pure resistor. Therefore, the PFC converter fed load system consumes active power. Also, power flow is unidirectional from the mains to the load. However, in future power grids with substantial renewable energy sources of an intermittent nature, the assumption that the mains voltage can be stable within the +/−6% is questionable.
SUMMARY OF THE INVENTION
[0011] The present invention is directed a method and apparatus for stabilizing a power grid that includes substantial intermittent energy sources by using bidirectional reactive power controller arrangements.
[0012] In an illustrative embodiment an ac-dc power converter, which may be found on a number of consumer products connected to the mains, is modified so that it has input voltage control, which in turn allows it to act as a smart load and to stabilize the grid. Naturally the grid is too powerful for any one converter to balance it, so it is contemplated that the converters will be implemented in a vast number of products so that the overall effect will be a stabilized grid.
[0013] The distinctive feature of the invention with respect to the traditional ac-dc power conversion method is illustrated in FIG. 6 . In a traditional schematic, there is no input voltage control because the existing mains voltage in is well regulated. As previously explained, the distributed and intermittent nature of renewable energy sources may cause power imbalance between power generation and load demand, leading to the possibility of power instability such as fluctuation in the mains voltage. The mains voltage in future power grids may not be stable. Therefore, “input voltage control” is proposed for ac-dc power converters with both active and reactive power flow control. The principle applies to both single-phase and multi-phase systems.
[0014] In the Hui published patent application, the electric load is connected in series with filter capacitor C of the power converter ( FIG. 7A ). The corresponding power flow diagram is shown in FIG. 7B . Active power does not flow through the power converter. Since the dc bulk capacitor of the power converter in FIG. 7A does not consume active power, the power converter in FIG. 7A only handles reactive power.
[0015] There is also one version of the reactive power controller arrangements in Hui that can handle both active and reactive power as shown in FIG. 8 . It should be noted that this power converter circulates active power through the power converter, and that the active power does not come from the electric load. This is in fact a limitation in the proposal described in Hui. This means that active power cannot be transferred from the electric load back to the a.c. mains supply in the proposal of Hui. However, according to the present invention, the electric load is connected to the d.c. bulk capacitor such that the power converter in FIG. 9A handles both active and reactive power. The power flow diagram of this embodiment of the invention is shown in FIG. 9B . Both active and reactive power components have to go from the mains to the load through the power converter in the present invention. A comparison of the power flow diagram in FIG. 7B with that in FIG. 9B , highlights the major differences between the present invention and that of the Hui publication. Since the power converter in this proposal can handle both active and reactive power, the input voltage and current can be in any phase relationship.
[0016] The present invention is particularly useful for electric loads with energy storage elements. For example, electric vehicles have batteries and, if necessary, active power can be transferred from the batteries to the a.c. mains supply.
[0017] The present invention proposes a new approach in order to utilize the electric spring concept in stabilizing future power grids. Similar to the electric spring implementation described in Hui, this new realization has some of the same electric spring features. These include:
[0018] (i) the use of “input voltage control” in the power converter with the mains voltage as input,
[0019] (ii) the use of a power converter such as a power inverter (i.e. ac-dc power converter), and
[0020] (iii) the provision of input voltage regulation functions (i.e. the regulation of the mains voltage).
[0000] However, unlike the approach in Hui, the present invention has the following differences as illustrated in FIG. 7B and FIG. 9B using a single-phase system as an example (the principle also applies to multi-phase systems).
[0021] (i) The electric load is connected to the bulk d.c. capacitor of the power converter (while the electric load in Hui is connected in series with the filter capacitor of the power converter).
[0022] (ii) Electric loads can include a second power converter stage, an energy storage device and the output load.
[0023] (iii) The power converter can handle BOTH active and reactive power (while the power converter in Hui can only handle reactive power).
[0024] (iv) Active and reactive power can flow in BOTH directions, i.e. from the mains to the power converter and vice versa.
[0025] (v) The vectors of the input voltage and input current of the power converter are NOT necessarily fixed at perpendicular positions. They can be in any phase relationship.
[0026] (vi) The control parameter in the power converter can also include the mains frequency ωs to improve the power grid stability.
[0027] (vii) The output voltage of the power converter is regulated when the power converter ONLY provides reactive power compensation to the power grid.
[0028] (viii) The output voltage of the power converter is allowed to fluctuate when the power converter provides active power compensation to the power grid.
BRIEF DESCRIPTION OF DRAWINGS
[0029] The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings of illustrative embodiments of the invention wherein like reference numerals refer to like parts throughout the various figures unless otherwise specified and in which:
[0030] FIGS. 1A , 1 B and 1 C illustrate the electric spring concept for neutral, boosting and reduction functions;
[0031] FIG. 2 is a block diagram of a prior art reactive power converter in the form of an inverter;
[0032] FIGS. 3A and 3B are schematic diagrams of prior art half-bridge and full-bridge inverters, respectively, which can be used as reactive power converters;
[0033] FIG. 4 s a diagram illustrating the vector relationship between voltage and current in the reactive power controller of FIG. 2 when the current I o is not zero;
[0034] FIGS. 5A and 5B are schematic diagrams of single-phase examples of prior art ac-dc power converters based on half-bridge and full-bridge power inverters, respectively, with “output voltage” regulation;
[0035] FIGS. 6A and 6B are schematic diagrams of, respectively, a prior art ac-dc power converter with output-voltage control and an ac-dc power converter with input voltage control according to the present invention;
[0036] FIG. 7A is a schematic diagram of a single phase power converter using an electric spring with reactive power control as in the Hui publication;
[0037] FIG. 7B is a power flow diagram of the power converter of FIG. 7A ;
[0038] FIG. 8 is block diagram illustrating one version of the electric spring in the Hui publication with a series power controller absorbing active power and a shunt power controller feeding the active power back to the mains power lines.;
[0039] FIG. 9A is a schematic diagram of a single phase power converter using an electric spring with both active and reactive power control in accordance with an embodiment of the present invention;
[0040] FIG. 9B is a power flow diagram of the power converter of FIG. 9A ;
[0041] FIG. 10 is a block diagram of an output-voltage control in a prior art ac-dc power conversion with well-regulated mains voltage;
[0042] FIG. 11 is a block diagram of an ac-dc power converter with input-voltage control according to an embodiment of the present invention where the mains voltage may not be stable due to intermittent renewable energy sources on the grid;
[0043] FIG. 12 is a block diagram of an ac-dc power converter with an input-voltage control according to another embodiment of the present invention with auxiliary control signals to improve transient and dynamic power system stability;
[0044] FIG. 13 is a block diagram of an ac-dc power converter with an input-voltage control according to a further embodiment of the present invention using a current mode control method:
[0045] FIG. 14 is a block diagram of an ac-dc power converter with input-voltage control according to a still further embodiment of the present invention; and
[0046] FIG. 15 is a block diagram of an ac-dc power converter with input-voltage control according to a yet another embodiment of the present invention.
DETAILED DESCRIPTION
[0047] The main objective of using a bi-directional ac-dc power converter with flexible control of the vector relationships of the input voltage and input current of the ac-dc power converter is to provide a new mechanism of regulating the mains voltage. This objective is achieved with the help of an input voltage control loop ( FIG. 5 ). An electric load with this front end bidirectional ac-dc power converter and the input voltage control can be considered as a new form of “smart load” that can help stabilize the mains voltage in future power grids that may be subject to disturbance and fluctuation caused by the intermittent nature of renewable power sources. The converter in this proposal can also perform load demand response, such as load shedding, or even provide active power compensation/injection to the power grid to improve the power balance.
[0048] The bidirectional ac-dc power converters concerned in this invention not only include standard power converters constructed with converter legs comprising power switches in 2-level or N-level totem-pole arrangements, but also include other variants of ac-dc power converters such as the Z-inverters. The principle applies to both single-phase and multi-phase systems.
[0049] FIG. 10 shows the traditional “output-voltage control” scheme of bi-directional ac-dc power converters 100 . No input voltage control is used traditionally because in existing power systems with no or limited intermittent renewable power generation, tight mains voltage (V s ) regulation can be assumed. As shown in FIG. 10 the dc output voltage V dc is compared to a reference voltage in comparator 102 . The difference signal is applied to PI Controller 104 , whose output is multiplied with the input mains voltage V s in a multiplier 106 . The input current I s — mea is measured and applied to current mode control 108 . The output of multiplier 106 is the current reference signal I s ref , which is also applied to Current Mode Control 108 . The output of the Current Mode Control 108 drives the Pulse-Width Modulation Generator 110 which sets the pulse width and frequency in the AC power Converter 100 . The input current (Is) is switched and shaped by the AC power Converter into the required sinusoidal shape with magnitude and phase angle according to the Is — ref .
[0050] FIG. 12 shows a version of the new input-voltage control scheme for bi-directional ac-dc power converters 100 with both active and reactive power flow control. The mains voltage (V s ) at which this power converter is installed is sensed as a feedback variable (shown in dashed lines). From this sensed voltage signal, the phase angle and/or the frequency of the ac mains voltage can be obtained from circuit 118 . The sensed mains voltage is compared with a mains voltage reference (V s — ref ) in comparator 116 . The mains voltage reference can be derived with the Droop Characteristic circuit 113 based on the magnitude of the PWM signal (M), the reactive power (Q) and the input current (I s ). As depicted in FIG. 11 , the Droop Characteristic circuit can comprise a feedback gain K applied to signal M, and a comparison of that signal to the nominal mains signal V s in comparator 114 to derive the mains voltage reference (V s — ref ). The difference signal e Vs is applied to an error amplifier/compensator 112 . As shown in FIG. 11 the output of this circuit is applied to Magnitude and Phase Angle circuit 120 . Further, a Synchronization circuit 118 receives the mains signal V s and its output is also applied to circuit 120 . Circuit 120 generates at least two control variables, namely the magnitude (M) and the phase angle (σ) of the PWM, which are applied to the Gate Pattern Generator 110 ′, which in turn drives the front-stage ac-dc power converter 100 , with the objective of controlling the active and reactive power of the bidirectional ac-dc power converter so that the mains voltage Vs will be regulated to a certain mains voltage reference V s — ref . The more complex version shown in FIG. 12 includes a control circuit 122 whose output depends on the input current (Is), angular frequency (ωs), active power (P s ) and reactive power (Q s ). The output of circuit 122 and the Error Amplifier/Compensator 112 are combined in Real and Reactive Power Computation circuit 124 . The two outputs of circuit 124 are applied to Magnitude and Phase Angle circuit 120 along with the output of Synchronization circuit 118 . The result is the magnitude control signal (M) and the phase angle (σ).
[0051] For a single-phase bidirectional ac-dc power converter, this PWM voltage applied to converter 100 from gate pattern generator 110 ′ is the voltage between points x and y (i.e. V xy ) in FIG. 9A . Beside the magnitude control signal (M) of V xy , the control loop also provides the phase angle (σ) which is the angle between V s and V xy . With the control of V xy and σ, the magnitude and phase angle of input current (i.e. the input inductor current) can be controlled. Therefore, both active and reactive power can be controlled to regulate the mains voltage to the mains voltage reference value at the location of the installation.
[0052] Another input voltage control scheme is shown in FIG. 13 . In this control scheme, both the input voltage (V s ) and the input current (Is) are sensed. Information, such as input voltage (V s ), input current (Is), angular frequency (ω s ), phase angle between Vs and Is, active power (P) and reactive power (Q), are thus obtained. With the knowledge of P and Q and the help of a synchronous circuit 118 , the magnitude (M) and angle (σ) control signals for the ac-dc power converter 100 can be derived with the objective of regulating the input mains voltage Vs to follow its reference V s — ref .
[0053] FIG. 11 and FIG. 12 show two control schemes that generate control signals for the PWM voltage of the bi-directional ac-dc power converter. These two schemes control the input current indirectly, by directly controlling the PWM voltage of the ac-dc power converter. The alternative control scheme as shown in FIG. 13 uses a direct current control. The direct current control scheme in FIG. 13 is similar to that of the indirect current control schemes in terms of the use of voltage and droop control. However, the magnitude and angle control variables which this scheme generates are for the direct control of the input current. In FIG. 13 , the instantaneous input current is sensed in circuit 126 and fed into a current control loop for comparison with the current reference I s — q — ref generated at the output of the error circuit 112 by the input voltage control scheme. This input current (I s ) is switched and shaped by the bi-directional power converter into the required sinusoidal shape with magnitude and phase angle according to the input voltage control with the objective of regulating the input ac voltage. In particular, quadrature phase current I s — q is compared to I s — q — ref in comparator 128 . The in-phase current I s — p is compared to the reference current I s — p — ref from the output of the dc voltage control loop in comparator 130 . The outputs of the comparators 128 , 130 are directed to the Current Mode Control 120 ′, which in turn drives the Gate Pattern Generator 110 ′.
[0054] An example of the implementation of the input voltage control scheme based on a proportional-integral (PI) compensator is shown in FIG. 14 . In FIG. 14 the input voltage is sampled and applied to both a Root-Mean Square Converter 132 and a Phase-Locked Loop circuit 134 . Comparators 114 and 116 are used to generate the output e Vc in the same way as shown in FIG. 11 , except that one of the inputs to comparator 116 is the output of Root-Mean Square Converter 132 instead of the input voltage Vs. The signal e Vc is applied to the Proportional-Integral (PI) compensator 136 , whose output is applied to Magnitude Calculation circuit 138 . Note that circuit 138 does not generate a phase signal, only the magnitude signal M. Further, the signal M drives the Sinusoidal Wave Generator 140 . The output of Phase-Locked Loop circuit 134 is also applied to generator 140 , which has an output that drives the PWM generator 142 . Generator 142 controls the AC-Power Converter 100 .
[0055] The input voltage control scheme proposed in this invention does not exclude a control methodology that involves the use of output voltage feedback to assist the proposed input voltage control. An example of an implementation of the input voltage control scheme of FIG. 11 , as represented by the arrangement of FIG. 14 , assisted with the output voltage feedback for the “input voltage control” of the bi-directional power converter, is shown in FIG. 15 . In particular, instead of the output of the Phase-Locked Loop circuit 134 being applied directly to generator 140 , it is applied to a comparator 156 . The dc output voltage of the arrangement V dc is compared to a reference in comparator 150 . The output e dc drives a second PI controller 152 , whose output drives an Angle Calculation circuit 154 . The output of the Angle Calculation circuit 154 is the second input to comparator 156 . It is the output of comparator 156 that drives the Sinusoidal Wave Generator 140 along with the signal M from the Magnitude Calculation circuit 138 .
[0056] While certain exemplary techniques have been described and shown herein using various methods and systems, it should be understood by those skilled in the art that various other modifications may be made, and equivalents may be substituted, without departing from claimed subject matter. Additionally, many modifications may be made to adapt a particular situation to the teachings of the claimed subject matter without departing from the central concept described herein. Therefore, it is intended that the claimed subject matter not be limited to the particular examples disclosed, but that such claimed subject matter may also include all implementations falling within the scope of the appended claims, and equivalents thereof.
[0057] Any reference in this specification to “one embodiment,” “an embodiment,” “exemplary embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. In addition, any elements or limitations of any invention or embodiment thereof disclosed herein can be combined with any and/or all other elements or limitations (individually or in any combination) or any other invention or embodiment thereof disclosed herein, and all such combinations are contemplated with the scope of the invention without limitation thereto.
[0058] It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application. | A family of power converters has input ac voltage regulation instead of output dc voltage regulation. The bi-directional converters control power flows and maintain the input ac voltage at or close to a certain reference value. These bi-directional power converters handle both active and reactive power while maintaining the input ac voltage within a small tolerance. Use of these converters is favorable for future power grid maintenance in that they (i) ensure the load demand follows power generation and (ii) provide distributed stability support for the power grid. The converters can be used in future smart loads that help stabilize the power grid. |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 2009-0024884, filed on Mar. 24, 2009 with the Korean Intellectual Property Office (KIPO), the entire contents of which are herein incorporated by reference.
BACKGROUND
1. Field
Example embodiments relate to a connection structure for a circuit board using a solder bump to connect two circuit boards.
2. Description of the Related Art
A printed circuit board (PCB) may serve to connect a plurality of electronic devices in a certain framework and is widely employed in a number of electronic products including, for example, electrical home appliances, e.g., digital TVs and advanced telecommunication devices.
In certain electronic devices, for example, a mobile phone or a digital camera, a thin folding type flexible printed circuit (FPC) is used for fabrication of an internal wiring. With increased miniaturization as well as enlargement of a movable part in the mobile phone, such FPC is increasingly used. When connecting the FPC to a rigid substrate used as a main board, a connector or an anisotropic conductive film (ACF) may be used.
Connectors are well known and widely used to provide a connection between boards and, in particular, may have a merit of repetitive attachment/detachment of FPC. However, it is difficult to employ connectors with complicated shapes in automatic connections thereof and to reduce a size of the connector due to three-dimensional space occupied thereby.
An ACF is a thermosetting resin film containing conductive single particles. In adhering the ACF at a terminal part of one substrate and laminating a terminal of another substrate over the adhered ACF, the laminate is pressed so that a conductive terminal is inserted between two opposite electrode faces, thereby guaranteeing electrical through-connection between terminals via the inserted conductive terminal. The ACF connection may have merits in connection of narrow pitches. However, as the conductive particle connects with the terminals, it may exhibit higher resistance at connection parts as compared to soldering connection. Because the resin hardens over time, the resin is duly removed using a particular solvent. Accordingly, the ACF described above has problems of increased time and/or cost, as compared to repairing of soldered products.
BRIEF SUMMARY OF THE INVENTION
Example embodiments provide a connection structure for a circuit board fabricated using a solder bump to connect two circuit boards.
Example embodiments provide a connection structure for a circuit board, fabricated using a solder bump to arrange two circuit boards and maintain the arrangement.
In accordance with example embodiments, a connection structure for a circuit board may include a first circuit board having at least one first connection terminal, a second circuit board having at least one second connection terminal, and at least one solder bump on the at least one first connection terminal. In example embodiments, the at least one second connection terminal may include a connecting part receiving at least a part of the at least one solder bump.
In accordance with example embodiments, a connection structure of a circuit board may include a first circuit board having at least one first connection terminal, a second circuit board having at least one second connection terminal corresponding to the first connection terminal, and at least one connecting protrusion electrically connecting the at least one first connection terminal to the at least one second connection terminal. In example embodiments, the at least one connecting protrusion may be on the first circuit board and the second circuit board may have a perforated part coupled with the at least one connecting protrusion.
In accordance with example embodiments, a process for connection of circuit boards using a solder bump to connect a first circuit board and a second circuit board may include preparing the solder bump on one of the first circuit board and the second circuit board and inserting the solder bump into the other of the first circuit board and the second circuit board.
In accordance with example embodiments, a connection structure for a circuit board may include a first circuit board having at least one first connection terminal, a second circuit board having at least one second connection terminal, and a solder bump placed at the first connection terminal. In example embodiments, the second connection terminal may have a connecting part to receive at least a part of the solder bump.
In this regard, the second circuit board may include a perforated part to receive at least a part of the solder bump and the connecting part may be placed in the perforated part.
In example embodiments, the connecting part may be positioned to enclose an inner side of the perforated part or, otherwise, to enclose the periphery of the perforated part.
In example embodiments, the solder bump may be smaller than the perforated part.
In example embodiments, the solder bump may include a part smaller than the perforated part.
In example embodiments, the perforated part may be formed in a round shape while the connecting part may be formed in a ring shape.
In example embodiments, the first connection terminal may comprise a plurality of connection terminals aligned in zig-zag form. Likewise, the second connection terminal may comprise a plurality of connection terminals aligned in zig-zag form.
In example embodiments, the connection structure may further include a first solder mask to prevent or reduce the plural first connection terminals from being interconnected.
In example embodiments, the connection structure may further include a second solder mask to prevent or reduce the plural connection terminals from being interconnected.
In example embodiments, the first connection terminal may comprise a plurality of connection terminals aligned in a row. Likewise, the second connection terminal may comprise a plurality of connection terminals aligned in a row.
In example embodiments, the connecting part may be fixed to the solder bump so as to arrange positions of the first circuit board and the second circuit board.
In accordance with example embodiments, a connection structure for a circuit board may include a first circuit board having at least one first connection terminal, a second circuit board having at least one second connection terminal which corresponds to the first connection terminal, and at least one connecting protrusion to electrically connect the first connection terminal to the second connection terminal. In example embodiments, the connecting protrusion may be placed on the first circuit board and the second circuit board may have a perforated part to be coupled with the connecting protrusion.
In example embodiments, the second connection terminal may include a connecting part in the perforated part and the connecting part may be coupled with the connecting protrusion.
In example embodiments, the perforated part and the connecting part may receive at least a part of the connecting protrusion.
In accordance with example embodiments, a process for connection of circuit boards performed using a solder bump to connect a first circuit board and a second circuit board may include preparing the solder bump on one of the first circuit board and the second circuit board, and inserting the solder bump into the other of the first circuit board and the second circuit board.
In example embodiments, the above connection process may further include fusing the solder bump.
In example embodiments, the above connection process may further include supplying fused solder between the first circuit board and the second circuit board.
In example embodiments, the second circuit board may have a perforated part to receive the solder bump.
As disclosed above, the circuit board connection structure according to example embodiments may arrange two circuit boards without additional equipment in a process for connection of circuit boards.
According to the example process for connection of circuit boards, the circuit board is not pushed during sliding a soldering iron tip so as to prevent or retard the arrangement of two circuit boards from being distorted and to inhibit an increase in transfer resistance due to lack of solder between two electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
Example embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. FIGS. 1-9 represent non-limiting, example embodiments as described herein. In accordance with example embodiments:
FIG. 1 is a plan view illustrating a first circuit board and a second circuit board in a circuit board connection structure according to example embodiments, before connection thereof;
FIG. 2 is a cross-sectional view taken along the line A-A shown in FIG. 1 ;
FIG. 3 is a cross-sectional view taken along the line B-B shown in FIG. 1 ;
FIG. 4 is a plan view illustrating the first circuit board and the second circuit board connected to each other using the circuit board connection structure according to example embodiments;
FIG. 5 is a cross-sectional view taken along the line C-C shown in FIG. 4 ;
FIG. 6 is a cross-sectional view taken along the line D-D shown in FIG. 4 ;
FIG. 7 shows a second connection terminal according to example embodiments;
FIG. 8 shows a first circuit board according to example embodiments; and
FIG. 9 shows alignment of a first connection terminal and a second connection terminal according to example embodiments.
DETAILED DESCRIPTION
Example embodiments will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the sizes of components may be exaggerated for clarity.
It will be understood that when an element or layer is referred to as being “on”, “connected to”, or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or layer or intervening elements or layers that may be present. In contrast, when an element is referred to as being “directly on”, “directly connected to”, or “directly coupled to” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, and/or section from another element, component, region, layer, and/or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of example embodiments.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
Example embodiments described herein will refer to plan views and/or cross-sectional views by way of ideal schematic views. Accordingly, the views may be modified depending on manufacturing technologies and/or tolerances. Therefore, example embodiments are not limited to those shown in the views, but include modifications in configuration formed on the basis of manufacturing processes. Therefore, regions exemplified in figures have schematic properties and shapes of regions shown in figures exemplify specific shapes or regions of elements, and do not limit example embodiments.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including,” if used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
Reference will now be made in detail to example embodiments of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
A connection structure for a circuit board according to example embodiments will be described in detail with reference to the accompanying drawings.
FIG. 1 is a plan view illustrating portions of a first circuit board and a second circuit board in a circuit board connection structure according to example embodiments, before a connection thereof. FIG. 2 is a cross-sectional view taken along the line A-A shown in FIG. 1 . FIG. 3 is a cross-sectional view taken along the line B-B shown in FIG. 1 .
As shown in FIGS. 1 to 3 , a circuit board connection structure may be employed for connection of circuit boards with a variety of types and shapes. Such a structure may include a first circuit board 10 having at least one first connection terminal 11 , a second circuit board 20 having at least one second connection terminal 22 , and a solder bump 30 in order to connect the first connection terminal 11 to the second connection terminal 22 . Each of the first circuit board 10 and the second circuit board 20 may comprise a rigid circuit board or a flexible circuit board. Because the solder bump 30 connects the first connection terminal 11 to the second connection terminal 22 , the solder bump 30 may allow current to pass from the first connection terminal 11 to the second connection terminal 22 and from the second connection terminal 22 to the first connection terminal 11 .
The first connection terminal 11 may be integrated into the first circuit board 10 . The first connection terminal 11 may have a first connecting part 12 in a flat form with the solder bump 30 on the flat first connecting part 12 . The solder bump 30 may be fixed to the first connecting part 12 of the first connection terminal 11 and may be protruded to a certain height. In example embodiments, the height may or may not be predetermined. FIGS. 1 to 3 illustrate the solder bump 30 in an approximately spherical form, however, the shape of the solder bump 30 is not particularly limited thereto and may be embodied in a variety of forms.
In FIG. 1 , a plurality of first connection terminals 11 may be used. In order to perform general functions of the first circuit board 10 , it may be necessary to prevent the plurality of first connection terminals 11 from being interconnected during connection of the circuit board. Therefore, the first connection terminals 11 may be spaced from one another at a certain interval. When a large number of first connection terminals 11 are used, that is, when a pitch spacing between adjacent first connection terminals 11 is relatively small, aligning the first connection terminals 11 in a zig-zag form as shown in FIG. 1 may prevent them from being interconnected or may reduce an interconnection that may form therein. Also, a first solder mask 13 may be integrated into the first circuit board 10 in order to enclose the plurality of first connection terminals 11 so that interconnection of the first connection terminals 11 optionally caused by impurities may be prevented or reduced.
In example embodiments, it may be required that the first connecting part 12 of each of the first connection terminals 11 be connected with a second connecting part 23 of each of the second connection terminals 22 and, therefore, the first solder mask 13 may not cover the first connecting part 12 of the first connection terminal 11 and surroundings thereof. The first connecting parts 12 of the plurality first connection terminals 11 may be spaced from one another and the first solder mask 13 may be formed between and around the first connecting parts 12 so that interconnection of the first connection parts 12 of the first connection terminals 11 by fused solder during connection of the circuit board may be prevented or reduced.
The second connection terminal 22 may be formed or placed on the second circuit board 20 . The second connection terminal 22 may have the second connecting part 23 in a ring form, into which the solder bump 30 may be inserted. In other words, the second circuit board 20 may include a perforated part 26 opening in a vertical direction and the second connecting part 23 of the second connection terminal 22 may be in the perforated part 26 . The second connecting part 23 of the second connection terminal 22 may be formed on an inner side 27 of the perforated part 26 . Such second connecting part 23 of the second connection terminal 22 may be constructed so that the solder bump 30 may be inserted into the perforated part 26 , thereby being easily connected with the solder bump 30 . FIGS. 1 to 3 illustrate a ring type second connecting part 23 of the second connection terminal 22 , however, a shape of the second connecting part is not particularly limited thereto and may be embodied in a variety of forms.
A plurality of second connection terminals 22 may be used. In order to perform general functions of the second circuit board 20 , it may be necessary to prevent the plurality of second connection terminals 22 from being optionally interconnected during connection of the circuit board. Therefore, the second connection terminals 22 may be spaced from one another at a certain interval. In example embodiments, the certain interval may or may not be predetermined. When a large number of second connection terminals 22 are used, that is, when a pitch spacing between adjacent second connection terminals 22 is relatively small, aligning the second connection terminals 22 in a zig-zag form as shown in FIG. 1 may prevent them from being interconnected or reduce an interconnection that may form between the second connection terminals 22 . Also, a second solder mask 24 may be formed on the second circuit board 20 in order to enclose the plurality of second connection terminals 22 so that interconnection of the second connection terminals 22 optionally caused by impurities may be prevented or retarded. In example embodiments, it may be required that the second connecting part 23 of each of the second connection terminals 22 be connected with a first connecting part 12 of each of the first connection terminals 11 and, therefore, the second solder mask 24 may not cover the second connecting part 23 of the second connection terminal 22 and surroundings thereof.
FIG. 4 is a plan view illustrating the first circuit board 10 and the second circuit board 20 connected to each other in the circuit board connection structure according to example embodiments. FIG. 5 is a cross-sectional view taken along line C-C as shown in FIG. 4 . FIG. 6 is a cross-sectional view taken along line D-D as shown in FIG. 4 .
As shown in FIGS. 4 to 6 , the connection structure for a circuit board according to example embodiments may be employed to arrange the first circuit board 10 and the second circuit board 20 using the solder bump 30 . In example embodiments, the first circuit board 10 may be placed under a bottom surface of the second circuit board 20 . In example embodiments, the solder bump 30 formed on the first circuit board 10 is inserted into the perforated part 26 of the second circuit board 20 . If a plurality of solder bumps 30 are inserted into a plurality of perforated parts 26 , the plurality of first connection terminals 11 may correspond to a plurality of second connection terminals 22 , respectively, so that arrangement of the first circuit board 10 and the second circuit board 22 may be easily embodied.
In example embodiments, the second circuit board 20 may be fixed to the solder bump 30 . Accordingly, the solder bump 30 may restrict movement of the second circuit board 20 relative to the first circuit board 10 . Therefore, the solder bump 30 may continuously maintain an arrangement of the first circuit board 10 and the second circuit board 20 . As shown in FIG. 5 , the first circuit board 10 may be connected with the second circuit board 20 by sliding soldering. Therefore, the second circuit board 20 may be fixed to the solder bump 30 and movement thereof may be restricted even if a soldering iron tip 40 slides over or contacts the second circuit board 20 . Accordingly, an arrangement of the first circuit board 10 and the second circuit board 20 may be maintained. In this regard, the soldering iron tip 40 may stably supply fused solder 41 between the first connection terminal 11 and the second connection terminal 22 , thereby solving a problem of increased transfer resistance caused by lack of solder between both connection terminals 11 and 22 .
In example embodiments it is not necessary to entirely insert the solder bump into the perforated part 26 . In example embodiments, the solder bump 30 may not be entirely inserted into the perforated part 26 , instead only a portion of the solder bump 30 may be inserted into the perforated part 26 . By inserting only a portion of the solder bump 30 into the perforated part 26 arrangement of the first circuit board 10 and the second circuit board 20 may be easily performed. That is, if the solder bump 30 has a part inserted into the perforated part 26 , the first circuit board 10 and the second circuit board 20 may be easily arranged even though the formed solder bump 30 is larger than the perforated part 26 .
Hereinafter, a process for connecting circuit boards using the connection structure for a circuit board according to example embodiments will be described in greater detail.
Referring to FIGS. 1 to 6 , the solder bump 30 is placed on the first circuit board 10 . More particularly, the solder bump 30 is positioned to fix the same to the first connecting part 12 of the first connection terminal 11 .
According to example embodiments, the perforated part 26 is formed on the second circuit board 20 . The perforated part 26 may be larger than the solder bump 30 in order to receive the solder bump 30 . However, even if the formed perforated part 26 is smaller than the solder bump 30 , example embodiments may be favorably employed when the perforated part 26 is formed to receive at least a part of the solder bump 30 .
The first circuit board 10 is connected with the second circuit board 20 using the solder bump 30 . The solder bump 30 formed on the first circuit board 10 is inserted into the perforated part 26 formed on the second circuit board 20 . While maintaining arrangement of the first circuit board 10 and the second circuit board 20 , the solder iron tip 40 slides over the second circuit board 20 and supplies fused solder 41 between the first connection terminal 11 and the second connection terminal 22 . As a result, the solder bump 30 is fused and connects the first connection terminal 11 and the second connection terminal 22 .
In example embodiments, the solder iron tip 40 may heat and melt the solder bump 30 , thus, the melted solder from the solder bump 30 may spread and flow to connect the first connecting part 12 to the first connection terminal 11 . Additionally, fused solder 41 may be supplied to the connection part, that is, in the perforated part 26 occupied by the solder bump 30 , to connect the solder bump 30 to the second connection terminal 22 . As another alternative, the iron tip 40 may be configured to melt the solder bump 30 and provide solder in the perforated part 26 to connect the first connecting part 12 to the second connection terminal 11 .
FIG. 7 illustrates a second connection terminal according to example embodiments.
As shown in FIG. 7 , a second connection terminal 22 a may be integrated into a second circuit board 20 a . A second connecting part 23 a of the second connection terminal 22 a may be placed in the perforated part 26 a , which may be the same as illustrated in FIG. 2 except that a second connecting part 23 a of the second connection terminal 22 a may be not positioned at an inner side 27 a of the perforated part 26 a . That is, the second connecting part 23 a of the second connection terminal 22 a may be formed along an external periphery of the perforated part 26 a at a top side of the perforated part 26 a . In example embodiments, a process for fabrication of the second circuit board 20 a may be relatively easy and simple.
The solder bump 30 a may be inserted into the perforated part 26 a to supply fused solder to the first and second connection terminals 11 a and 22 a while maintaining arrangement of the first circuit board 10 a and the second circuit board 20 a , so that the first connection terminal 11 a may be connected with the second connection terminal 22 a via the solder bump 30 a . Like example embodiments according to FIG. 1 , the first connection terminal 11 a may include a first connecting part 12 a and a first solder mask 13 a may be formed on a surface of the first circuit board 10 a.
FIG. 8 shows a first circuit board according to example embodiments.
As shown in FIG. 8 , a solder mask 13 b may be placed on a first circuit board 10 b to enclose a first connection terminal 11 b . However, the solder mask 13 b may not be present in a region S including a first connecting part 12 b of the first connection terminal 11 b and surroundings thereof. Referring to FIG. 1 , the first solder mask 13 may be placed between plural first connecting parts 12 of first connection terminals 11 . However, in FIG. 8 , if an amount of supplied fused solder is accurately controlled during fabrication of a circuit board, interconnection of the plural first connection parts 12 b of the first connection terminals 11 b may be prevented or reduced even though the solder mask 13 b is not present in the region S including the first connecting part 12 b of the first connection terminal 11 b and surroundings thereof as shown in FIG. 8 . In FIG. 8 , 30 b represents a solder bump accurately formed in the region S.
FIG. 9 shows alignment of a first connection terminal and a second connection terminal according to example embodiments.
As shown in FIG. 9 , a first connection terminal 11 c may be integrated into a first circuit board 10 c while a second connection terminal 22 c may be integrated into a second circuit board 20 c . Each of the first connection terminal 11 c and the second connection terminal 22 c may comprise a plurality of connection terminals. FIG. 9 illustrates a plurality of first connecting parts 12 c of the plural first connection terminals 11 c and a plurality of second connecting parts 23 c of the plural second connection terminals 22 c aligned in respective rows. If a small number of first connection terminals 11 c and second connection terminals 22 c are used, that is, if a pitch spacing between adjacent first connecting parts 12 c of the first connection terminals 11 c or between adjacent second connecting parts 23 c of the second connection terminals 22 c is relatively large, decreasing possibility of connection by fused solder during fabrication of a circuit board, it may be possible to align a plurality of first connecting parts 12 c of first connection terminals 11 c and a plurality of second connecting parts 23 c of second connection terminals 22 c in respective rows. In addition, a plurality of solder bumps 30 c may also be aligned in a row to correspond to a plurality of first connecting parts 12 c of first connection terminals 11 c.
Although example embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in example embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. | Disclosed is a connection structure for a circuit board using a solder bump to arrange circuit boards. The circuit board connection structure includes a solder bump prepared on one of two circuit boards and a perforated part formed at the other of the circuit boards to receive the solder bump. Facing both circuit boards towards each other and inserting the solder bump into the perforated part, the circuit boards are desirably arranged. |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation-in-part of a co-pending application entitled LATCH AND LOCK ASSEMBLIES WITH SPRING-BIASED PIVOT BOLTS, Ser. No. 072,174, now U.S. Pat. No. 4,850,208, filed July 10, 1987 by Lee S. Weinerman et al (referred to hereinafter as the "Predecessor Case"), which application was filed as a continuation-in-part of a prior application entitled CABINET LOCK WITH RECESSED HANDLE, Ser. No. 859,194 filed Apr. 28, 1986 by Lee S. Weinerman et al that issued Aug. 4, 1987 as U.S. Pat. No. 4,683,736, which prior application was filed as a continuation-in-part of an earlier application Ser. No. 601,648 filed Apr. 18, 1984 (now abandoned), with said prior and earlier applications being referred to hereinafter as the "Parent Cases," and with the disclosures of all of the Parent and Predecessor Cases being incorporated herein by reference.
Reference also is made to the following applications that were filed concurrently with said Predecessor Case, the disclosures of which are incorporated herein by reference:
LATCH AND LOCK HOUSINGS, HANDLES AND MOUNTING BRACKETS, Ser. No. 072,176, filed July 10, 1987 by Lee S. Weinerman, Steven A. Mayo, Joel T. Vargus, Frank R. Albris, Richard H. Russell, Thomas V. McLinden, Richard M. O'Grady and Timothy H. Wentzell, hereinafter referred to as the "Utility Case I;"
LATCH AND LOCK ASSEMBLIES WITH SPRING-BIASED SLIDE BOLTS, Ser. No. 072,177, filed July 10, 1987 by Lee S. Weinerman, Steven A. Mayo, Joel T. Vargus, Frank R. Albris, Richard H. Russell, Thomas V. McLinden, Richard M. O'Grady and Timothy H. Wentzell, hereinafter referred to as the "Utility Case II;"
LATCH AND LOCK ASSEMBLIES WITH LIFT AND TURN HANDLES, Ser. No. 072,175, filed July 10, 1987 by Lee S. Weinerman, Frank R. Albris, Thomas V. McLinden and Timothy H. Wentzell, hereinafter referred to as the "Utility Case IV;"
LATCH AND LOCK ASSEMBLIES WITH EXPANSIBLE LATCH ELEMENTS, Ser. No. 072,250, filed July 10, 1987 by Lee S. Weinerman, Steven A. Mayo, Thomas V. McLinden and Timothy H. Wentzell, hereinafter referred to as the "Utility Case V;"
HOUSINGS FOR LATCHES AND LOCKS, Ser. No. 072,282, filed July 10, 1987 by Richard H. Russell, David W. Kaiser and Richard M. O'Grady, hereinafter referred to as the "Design Case I;"
COMBINED HOUSINGS AND HANDLES FOR LATCHES AND LOCKS, Ser. No. 072,283, filed July 10, 1987 by Richard H. Russell, David W. Kaiser and Richard M. O'Grady, hereinafter referred to as the "Design Case II;"
COMBINED HOUSINGS AND HANDLES FOR LATCHES AND LOCKS, Ser. No. 072,285, filed July 10, 1987 by Richard H. Russell and David W. Kaiser, hereinafter referred to as the "Design Case III;"
COMBINED HOUSINGS AND HANDLES FOR LATCHES AND LOCKS, Ser. No. 072,284, filed July 10, 1987 by Richard H. Russell and David W. Kaiser, hereinafter referred to as the "Design Case IV;"
COMBINED HOUSINGS AND HANDLES FOR LATCHES AND LOCKS, Ser. No. 072,276, filed July 10, 1987 by Richard H. Russell and David W. Kaiser, hereinafter referred to as the "Design Case V;"
COMBINED HOUSINGS AND HANDLES FOR LATCHES AND LOCKS, Ser. No. 072,573, filed July 10, 1987 by Richard H. Russell and David W. Kaiser, hereinafter referred to as the "Design Case VI;"
COMBINED HOUSINGS AND HANDLES FOR LATCHES AND LOCKS, Ser. No. 072,277, filed July 10, 1987 by Richard H. Russell and David W. Kaiser, hereinafter referred to as the "Design Case VII;"
MOUNTING BRACKETS FOR LATCHES AND LOCKS, Ser. No. 072,278, filed July 10, 1987 by Richard H. Russell and Thomas V. McLinden, hereinafter referred to as the "Design Case VIII;"
MOUNTING BRACKETS FOR LATCHES AND LOCKS, Ser. No. 072,280, filed July 10, 1987 by Richard H. Russell and Thomas V. McLinden, hereinafter referred to as the "Design Case IX;"
STRIKERS FOR USE WITH LATCHES AND LOCKS, Ser. No. 072,279, filed July 10, 1987 by Lee S. Weinerman and Steven A. Mayo, hereinafter referred to as the "Design Case X;" and,
STRIKERS FOR USE WITH LATCHES AND LOCKS, Ser. No. 072,281, filed July 10, 1987 by Lee S. Weinerman and Steven A. Mayo, hereinafter referred to as the "Design Case XI."
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to flush mounted latches and locks of the type used with closures for industrial cabinets, tool carts, electrical equipment enclosures and the like. More particularly, the present invention relates to novel and improved latches and locks that utilize a highly versatile housing together with other interactive components of novel form to provide desired types of latching and locking actions.
2. Prior Art
Flush mounted latches and locks including a body, a latch bolt movably carried on the body, and an operating handle that is nested by the body are well known. Normally the handle is in a flush or nested position when the bolt is in a latched position; and unlatching movement of the bolt is effected by moving the handle to an operating position. Latches and locks of this type are well suited for use on industrial cabinets, tool carts, electrical equipment enclosures and the like.
Flush-mounted latches and locks having pan-shaped housings that nest paddle-shaped operating handles, and that have spring-projected slide bolts are disclosed in such U.S. Pat. Nos. as 4,335,595, 4,321,812, 4,320,642, 4,312,205, 4,312,204, 4,312,203, 4,312,202, 4,309,884, 4,231,597, 4,138,869, 3,707,862, 3,668,907, 3,449,005, 3,389,932, 3,357,734, 3,209,564, 3,209,563, 3,055,204, 2,987,908, 2,900,204 and 2,642,300, all of which are assigned to the Eastern Company, a corporation of Conn.
Flush mounted latches and locks having latch bolts of other than the spring-projected, slide-mounted type are disclosed in such U.S. Pat. Nos. as 4,413,849, 4,320,642, 4,312,203, 4,134,281, 3,857,594, 3,338,610, 3,044,814, 3,044,287 and 2,735,706, all of which are assigned to the Eastern Company.
A cabinet latch having a housing that is usable with a variety of pivotally mounted latch bolts, and with a variety of latching mechanisms is disclosed in U.S. Pat. No. 4,177,656, also assigned to the Eastern Company.
3. The Cross-Referenced Utility and Design Cases
The present invention, and the inventions described in the several referenced Utility and Design Cases, represent the work products of a long term and continuing development program.
The several functional features that form the subjects matter of the referenced Utility Cases, and the several appearance features that form the subjects matter of the referenced Design Cases, were developed by various co-workers, as is reflected in the listing of inventors in these cases. Many of the functional and appearance features that are claimed in separate ones of the referenced Utility and Design Cases were developed substantially concurrently.
If an invention feature that is disclosed in one of the referenced Utility and Design Cases constitutes a species of a development concept that is utilized in another of these related cases, it will be understood that care has been taken to present a generic claim in the case that describes the earliest development of a species that will support the generic claim. In this manner, a careful effort has been made to establish clear lines of demarcation among the claimed subjects matter of this and the several referenced Utility and Design Cases. No two of these cases include claims of identical scope.
4. The Referenced Predecessor Case
Because the best mode known to the inventors for carrying out the practice of the present invention is in conjunction with the basic type of latch and lock units that are disclosed in the referenced Predecessor Case, the text of the present case tracks quite closely the text of the Predecessor Case, and the drawings that are included herewith follow in the basic format and arrangement of the drawings of the Predecessor Case. Likewise, many of the claims that follow build upon claims that have have been allowed in the Predecessor Case.
5. The Referenced Parent Cases
The lock-type embodiment that is disclosed in the referenced Predecessor Case makes use of a key cylinder retaining means that also is disclosed in the referenced Parent Cases. This fact explains, at least in part, why the Predecessor Case was filed as a continuation-in-part of the referenced Parent Cases.
However, in the preferred practice of the present invention, the means by which key cylinders and the like are retained in their associated lock housings has been changed, resulting in a simplification of the construction of the lock-type embodiment, and in enhanced ease of assembly. Thus, the referenced Parent Cases are not as relevant to the invention of the present case as they were to the Predecessor Case.
SUMMARY OF THE INVENTION
The present invention provides novel and improved flush mountable latches and locks for industrial cabinets, tool carts, electrical equipment enclosures and the like, with the latches and locks utilizing a highly versatile housing together with other interactive components of novel form to provide desired types of latching and locking actions.
While the inventive features that form the subject matter of the present case are primarily intended for use as "improvements" in conjunction with the invention that forms the subject matter of the referenced Predecessor Case, it will be understood by those skilled in the art that a number of the improvement features that are described herein can be utilized with other forms of latch and lock structures, most especially those that are disclosed in the several referenced Utility and Design Cases which were filed July 10, 1987.
The inventive features that form the subject matter of the present application include improvements that enhance the ease with which latch and lock units of the basic type that are described in the referenced Predecessor Case can be fabricated and assembled, facilitate the optional addition to such latch and lock units of weatherproofing boot-type seals that may be interposed between housing and operating handle components, and enhance the ease with which such latch and lock units can be mounted on structures of a variety of thicknesses. Also, improvements are disclosed that enable components of such lock-type units to be assembled with greater ease, utilizing a smaller number of locking components that cooperate in advantageous ways to yield improvements in performance.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, and a fuller understanding of the invention may be had by referring to the description and claims that follow, taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is an exploded perspective view of one form of lock assembly that embodies features of the preferred practice of the present invention, illustrating how the lock assembly is mounted on a closure, and showing two types of strikers that may be used with the lock assembly, with front surface portions of the strikers being broken away;
FIG. 2 is an exploded perspective view of components of the lock assembly of FIG. 1;
FIG. 3 is a schematic top plan view, on a reduced scale, showing the lock assembly of FIG. 1 installed on a pivotal closure, with a striker shown in cross section and mounted on a cabinet wall, and with the closure in an open/position;
FIG 4 is a schematic top plan view similar to FIG. 3 but with the closure moved toward its closed position to bring a rearwardly projecting latch bolt of the lock assembly into engagement with the striker;
FIG. 5 is a schematic top plan view similar to FIGS. 3 and 4, but with the closure closed, and with the latch bolt in latched engagement with the striker;
FIG. 6 is a right side elevational view showing the lock of FIG. 1, with the handle assembly in its normally nested position, with the latch bolt pivoted to its latched position, and with locking components locked;
FIG. 7 is a rear elevational view thereof;
FIG. 8 is a bottom plan view thereof;
FIG. 9 is a rear elevational view similar to FIG. 7 but with the locking components unlocked;
FIG. 10 is a rear elevational view similar to FIG. 9 but with the latch bolt pivoted to its unlatched position, and with the handle assembly being held out of its nested position by the latch bolt;
FIG. 11 is a schematic view, partially in cross section, on an enlarged scale, showing the handle assembly in its normal nested position in relation to the housing, and showing the latch bolt latched, with the latch bolt being held in its latched position by its engagement with a rearwardly projecting portion of the handle assembly;
FIG. 12 is a schematic view similar to FIG. 11, but showing the handle assembly fully pivoted out of its nested position, and with the latch bolt unlatched;
FIG. 13 is a perspective view of portions of the handle assembly and the housing, with housing portions broken away, with the handle assembly in its normal nested position with respect to the housing, and with the view showing principally rear features thereof;
FIG. 14 is a sectional view, on an enlarged scale, as seen from a plane indicated by a line 14--14 in FIG. 2;
FIG. 15 is an exploded perspective view showing selected portions of the lock assembly, with alternate forms of a rotary plug that is insertable into the housing being shown;
FIG. 16 is an exploded perspective view showing a mounting plate and a shim member that is insertable into a recess that is defined by the mounting plate, it being understood that the shim member is installed in the recess only in the event that no resilient boot (of the type that is shown in FIGS. 2, 11 and 12) is installed in the mounting plate recess;
FIG. 17 is an exploded perspective view showing latch and lock assembly mounting components (including spacers of a variety of thicknesses that can be selected for use with the other depicted components) that cooperate to enable latch and lock assemblies to be installed on structures of a variety of thicknesses;
FIG. 18 is a sectional view, on an enlarged scale, showing a spring-biased retaining clip that is carried in a groove that is provided in rotary plugs of the type that are depicted in FIG. 15, with the clip shown fully radially inserted in opposition to the action of an associated leaf spring that also is carried in the groove;
FIG. 19 is a sectional view showing the components of FIG. 18 and including sleeve portions of a lock housing, as seen from a plane indicated generally by a line 19--19 in FIG. 8, and with the clip projecting from the groove of the rotary plug in which the clip is carried so as to cooperate with an end wall portion of the sleeve to retain the rotary plug within the sleeve; and,
FIG. 20 is a perspective view of a locking member that is employed in the lock assembly of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, one form of a snap-acting lock assembly that embodies features of the preferred practice of the present invention is indicated generally by the numeral 100. The lock assembly 100 has a housing 200 that mounts a plurality of interactive components that provide latching and locking functions.
In overview, and as will be explained in greater detail, the interactive components that are carried on the housing 200 principally include a handle assembly 300 that is mounted on the housing 200 for movement between normal and operating positions; a spring-pivoted latch bolt 400 that is mounted on the housing 200 for movement between latched and unlatched positions; a bracket and spring assembly 500 that mounts the latch bolt 400 on the housing 200 for movement between latched and unlatched positions, with movements of the latch bolt 400 to its unlatched position taking place in response to movement of the handle assembly 300 to its operating position; and, a locking mechanism 600 for selectively permitting and preventing unlatching movement of the latch bolt 400 by the handle assembly 300. If the locking mechanism 600 is omitted, the lock assembly 100 is thereby transformed into a latch assembly, i.e., a unit which has a handle assembly 300 that always can be operated to retract the latch bolt 400.
Referring to FIG. 1, it will be seen that the latch bolt 400 projects relatively sidewardly with respect to the housing 200 for engaging a suitably configured striker such as the strikers 180, 190 that are depicted in FIG. 1; however, those skilled in the art will understand that other types of strikers, as well as keeper formations of conventional, commercially available configurations, also may be used to engage and releasably retain the latch bolt 400.
The strikers 180, 190 have body structures 182, 192 that surround and define bolt-receiving chambers 184, 194, respectively. Openings 186, 196 are formed in the body structures 182, 192 and communicate with the chambers 184, 194, respectively. The openings 186, 196 are of adequate size to receive and releasably retain a tip portion of the latch bolt 400. Latch bolt engagement surfaces 188, 198 extend along one side of their associated openings 186, 196. Appearance features of the striker 180 are disclosed in greater detail in the referenced Design Case X. Appearance features of the striker 190 are disclosed in greater detail in the referenced Design Case XI.
The manner in which the latch bolt 400 of the lock assembly 100 cooperates with the striker 180 as the closure 110 is pushed to its closed position is depicted in the schematic top views of FIGS. 3-5. Referring to FIG. 3, when the closure 110 is open with respect to a cabinet structure 111 on which the closure 110 is pivotally mounted, the latch bolt 400 of the lock assembly 100 is pivoted (under the action of a torsion coil spring 510 that is shown in FIG. 2) to an unlatched position, i.e., to a position wherein the latch bolt 400 projects rearwardly and rightwardly as viewed in FIG. 3.
As the closure 110 is pivoted progressively toward its closed position, the latch bolt 400 is brought into engagement with the striker engaging surface 188 of the striker 180, as is shown in FIG. 4. Completion of the pivotal movement of the closure 110 to its closed position causes the engagement of the latch bolt 400 with the striker surface 188 to pivot the latch bolt 400 (in opposition to the action of the torsion spring 510) to the latched position of the latch bolt 400, as is shown in FIG. 5. As the latch bolt reaches its latched position, the handle assembly 300 pivots to its normally nested position (under the influence of a compression coil spring 360 that is shown in FIG. 2). When the handle assembly 300 pivots to its normally nested position, a rearwardly extending projection 320 of the handle assembly 300 moves into a position of retaining engagement with an end region 402 of the latch bolt 400 to hold the latch bolt 400 in its latched position (as is depicted schematically in FIG. 11).
Unlatching of the lock assembly 100 is effected by depressing the handle assembly 300, as is depicted schematically in FIG. 12. Pivotal movement of the handle assembly 300 to its operated position moves the projection 320 out of retaining engagement with the latch bolt end region 406, whereupon the latch bolt 400 pivots under the action of the torsion coil spring 510 to its unlatched position, as is depicted in FIG. 12. As the latch bolt 400 pivots to its unlatched position, the engagement between the latch bolt 400 and the striker surface 188 causes the closure 110 to be "popped open" to the position shown in FIG. 4.
Before turning to a more detailed description of the components of the lock assembly 100, the preferred manner in which the lock assembly 100 can be mounted on a closure 110 will be described. The portion of the closure 110 that is shown in FIG. 1 is a plate-like structure that has a mounting opening 112 formed therethrough. More extensive portions of the closure 110 are depicted schematically in FIGS. 3-5, as is associated cabinet structure 111. The closure portion 110 has a front surface 114 and a rear surface 116 that extend about the perimeter of the opening 112. As is best seen in FIG. 1, the opening 112 has top and bottom boundaries 122, 124, and left and right side boundaries 126, 128.
In order to mount the lock assembly 100 on the closure 110, the lock assembly 100 has a pair of mounting posts 700 that project rearwardly for connection to a mounting bracket 750. The mounting posts 700 have enlarged hexagonal head formations 701 near their rearward ends to enable the mounting posts 700 to be engaged by conventional wrenches and the like to facilitate the installation and tightening into place of the mounting posts 700. As will be explained, threaded holes 709 are formed through the mounting posts 700, thereby enabling the forward end regions of the mounting posts 700 to be threaded onto housing-carried studs 250, and enabling threaded fasteners 702 to be threaded into the rearward end regions of the mounting posts to connect the mounting bracket 750 to the housing 200.
The mounting bracket 750 is of generally U-shaped configuration, having a back wall 760 that connects at opposite ends with legs 762, 764. The legs 762, 764 extend forwardly from the plane of the back wall 760 toward the mounting flange 202, and cooperate with the housing 200 for clampingly mounting the lock assembly 100 on the closure 110. A notch 768 is formed in one side of the back wall 760 to provide a clear, unobstructed path of movement for the latch bolt 400. Appearance features of the mounting bracket 750 are disclosed in greater detail in the referenced Design Case VIII.
When the lock assembly 100 is to be installed on the closure 110, a gasket 270 is positioned to engage the mounting flange 202, and portions of the lock assembly 100 are installed through the closure opening 112 to position the gasket 270 adjacent the opening 112 in clamped engagement between the rear face 206 of the mounting flange 202 and the front surface 114 of the closure 110. The mounting bracket 750 is positioned to overlie the lock assembly 100, with the legs 762, 764 of the mounting bracket 750 extending extending into engagement with the rear surface 116 of the closure 110, and with the notch 768 overlying the bolt 400. Threaded fasteners 702 are installed to extend through holes 752 that are formed through the back wall 760 of the bracket 750. The fasteners 702 are threaded into the holes 709 that are formed through the mounting posts 700 of the lock assembly 100 to clamp the mounting flange 202 into engagement with the gasket 720, to clamp the gasket 720 into engagement with the front surface 114, and to clamp the legs 762, 764 into engagement with the rear surface 116.
Referring to FIGS. 1 and 2, an improvement feature of the present invention resides in the provision of optional spacers 703 that can be installed on the rearward end regions of the mounting posts 700 to increase the effective lengths of the mounting posts 700 as may be needed to accommodate a closure 110 (or other structure on which a latch or lock unit is being installed) that is of greater thickness than is accommodated by the lengths of the mounting posts 700 alone. The spacers 703 have through holes 705 that receive the threaded fasteners 702, with forward end regions of the through holes 705 being enlarged to provide hex-shaped recesses 707 that snugly receive and mate with the hex heads 701 of the mounting posts 700. By inserting a separate one of the spacers 703 on the rearward end region of each of the mounting posts 700, the effective lengths of the mounting posts 700 are increased such that, when the mounting bracket 750 is installed in engagement with the spacers 703, the mounting bracket 750 will be mounted slightly more rearwardly with respect to the mounting flange 202 of the housing 200 so that the legs 762, 764 will be farther spaced from the mounting flange 202 than would be the case if the spacers 703 were not used to extend the effective lengths of the mounting posts 700.
Referring to FIG. 17, spacers 703, 703a, 703b, 703c of a variety of thicknesses may be selectively used (in identical pairs) to extend the effective lengths of the mounting posts 700 to any desired extent, whereby the spacers 703, 703a, 703b, 703c enable the described type of latch and lock assemblies to be mounted on structures of substantially any given thickness. The spacers 703a, 703b, 703c differ from the spacers 703 only in thickness (i.e., in the extent to which they increase the effective lengths of the mounting posts 700).
To facilitate an understanding of the various relative positions of the principal relatively movable components of the lock assembly 100, reference is made to FIGS. 1 and 6-8 wherein the components of the lock assembly 100 are arranged such that: the handle assembly 300 is in its "normal" or "nested" position; the latch bolt 400 is in its "latched" or "projected" position; and the lock mechanism 600 is "locked" so as to prevent unlatching movement of the latch bolt 400 in response to attempted operation of the handle assembly 300. In FIG. 9, the mechanism of the lock 600 is shown "unlocked" so as to permit unlatching movement of the latch bolt 400 by operation of the handle assembly 300. In FIGS. 10 and 12, the handle assembly 300 is shown in its "operating" position wherein the handle assembly 300 functions to permit the latch bolt 400 to pivot to its "unlatched" position.
Turning now to a more detailed description of features of the components of the lock assembly 100, the housing 200 is preferably formed as a molded, one piece structure; thus it will be understood that the mounting flange 202 together with the walls that form an essentially pan-shaped housing portion 220 (i.e., the walls that define the width, length and depth of the recess 210) are integrally-formed parts of the same one-piece structure. The fabrication of the housing 200 as a one-piece member molded from thermoplastic, material such as a glass reinforced polycarbonate based polymer blend helps to provide a strong, rigid, impact resistant structure, whereby the housing 200 is capable of providing a versatile mounting platform for supporting the various relatively movable components of the lock assembly 100.
A preferred material from which the housing 200 is formed is a thermoplastic that is a glass reinforced polycarbonate based polymer blend, typically of the type sold by General Electric Company, Pittsfield, Mass. 01201 under the registered trademark XENOY. The most preferred resin blend is about 10 percent glass reinforced, and is selected from the "6000 Series" of the XENOY products sold by General Electric, with XENOY 6240 being preferred. While many other commercially available moldable plastics materials can be used to form the housing 200, as will be apparent to those skilled in the art, the preferred material helps to provide a high strength housing that is light in weight, resists crazing and hardening, is heat and chemical resistant, is resistant to impact, and can be machined as needed to provide suitable mounting holes and the like for movably mounting a wide variety of handles within the confines of the recess 210, as will be explained.
The mounting flange 202 has a front face 204 that defines the front of the housing 200. The mounting flange 202 has a rear face 206 that is substantially flat, i.e., all portions of the rear face 206 extend substantially in a single plane. The mounting flange 202 is bordered by a perimetrically extending edge surface 208 that joins the front and rear surfaces 204, 206 at their peripheries. While all portions of the mounting flange 202 are formed integrally and therefore serve to define elements of a one-piece structure, for purposes of reference, the mounting flange 202 can be thought of as having a top portion 212 that extends across the top of the recess 210, a bottom portion 214 that extends across the bottom of the recess 210, and opposed side portions 216, 218 that extend along left and right sides of the recess 210. Likewise, the edge surface 208 can be thought of as having a top portion 222, a bottom portion 224, and opposed side portions 226, 228. The flange portions 212, 214, 216, 218 and their associated edge portions 222, 224, 226, 228 cooperate to define a mounting flange 202 that has a generally rectangular configuration, with corner regions where adjacent ones of the edge portions 222, 224, 226, 228 join preferably being gently rounded to give an enhanced appearance.
The pan-shaped portion 220 of the housing 200 (i.e., the portion of the housing 200 that defines the forwardly facing recess 210) includes a top wall 232, a bottom wall 234, a pair of opposed side walls 236, 238, and a back wall 242. The back wall 242 is arranged so that it extends substantially parallel to the rear face 206 of the mounting flange 202. Stated in another way, the back wall 242 has a front face 244 and a rear face 246 that extend in planes that substantially parallel the plane of the rear face 206. Particular attention is paid to the molding of the rear face 246 of the back wall 242 so that the rear face 246 provides a smooth, planar back wall surface that can be utilized for the important function of mounting other components of the lock assembly 100, as will be explained.
For the purpose of providing an enhanced appearance, it is preferred that front face 204 of the housing 200 be of curved, slightly convex configuration. Stated in another way, the front face 204 is convexly curved such that the thicknesses of the mounting flange portions 212, 214, 216, 218 increase progressively the closer these formations extend toward an imaginary center point of the front face 204. Likewise, the thicknesses of the mounting flange portions 212, 214, 216, 218 decrease progressively as these formations extend toward the edge surface portions 222, 224, 226, 228. Preferably, the thicknesses of the mounting flange portions 212, 214, 216, 218 as measured at locations that are adjacent to the edge portions 222, 224, 226, 228, are substantially uniform all along the edge surface 208--which is to say that the edge surface 208 has a width that is substantially constant as the edge surface 208 extends about the housing 200. Appearance features of the front face 204 of the housing 200 are within the purview of the referenced Design Case I.
For the purpose of providing an enhanced appearance, the positioning of the top and bottom walls 232, 234 of the pan-shaped housing portion 220 that defines the recess 210 preferably is asymmetrical relative to top and bottom edges 222, 224 of the mounting flange 202. Likewise, for purposes of enhanced appearance, the positioning of the left and right side walls 236, 238 of the pan-shaped housing portion 220 preferably is asymmetrical relative to the left and right opposed side edges 226, 228 of the mounting flange 202. This absence of symmetry in locating the recess 210 relative to opposed top and side edge portions 222, 224 and 226, 228 of the mounting flange 202 results in the top wall portion 212 being relatively short in height in comparison with the relatively tall height of the bottom wall portion 214 that depends beneath the recess 210, and results in the left sidewall portion 216 being relatively wide, while the right side wall portion 218 is relatively narrow.
A feature of the invention resides in the provision of compact, simply configured locks and latches having pivotal latch bolts, with the functional, operating components thereof being arranged substantially symmetrically about an imaginary, vertically extending center plane designated in FIG. 7 by the numeral 201. In this regard, it will be understood that several functional features of the housing 200 are arranged substantially symmetrically about the center plane 201, including the side walls 236, 238 of the housing portion 220, and a sleeve-like housing formation 280, which will be described.
With respect to the side-to-side positioning of the recess 210 relative to features of the mounting flange 202, however, it will be understood that this is a feature dictated solely by appearance considerations, and not by functional considerations. Indeed, functional features of the lock assembly 100 would not be affected if the narrow flange portions 212, 218 were enlarged to give the flange portions 212, 218 widths that are equivalent to the relatively wider flange portions 214, 216, respectively. Likewise the styling of the front face 204 of the mounting flange 202 is dictated entirely by appearance considerations.
Threaded studs 250 project rearwardly from the rear face 246 of the back wall 242 for mounting various latch and lock components, as will be explained. Referring to FIG. 14, the threaded studs 250 have enlarged head portions 252 with radially outwardly extending projections 254 that have somewhat of a toothed washer appearance and that are located adjacent the head portions 252. The head portions 252 and the projections 254 are embedded within the molded material of the back wall 242 of the housing 200 to provide structures that are anchored securely to the plastics material and will not rotate with respect thereto. The studs 250 have elongate threaded shank portions 256 that project rearwardly from the head portions 252. The threaded shank portions 256 extend along spaced imaginary axes 251 that intersect the plane of the back wall 242 at right angles thereto. The axes 251 extend coaxially through the holes 752 that are formed in the back wall 760 of the mounting bracket 750. The axes 251 of the studs 250 are located equidistantly from the center plane 201, and are positioned on opposite sides of the center plane 201.
In preferred practice, the threaded studs 250 are commercially available fasteners that are sold by Penn Engineering and Mfg. Corp. of Danboro, Penna., under the trademark PEM. The preferred part is model number CHN-832-4, which is formed from stainless steel, has a tapered head 252 with a maximum diameter of about 0.289 inch, has radially extending projecting portions 254 that have a maximum outer diameter of about 0.328 inch, and has a shank length of about 0.250 inch that is threaded with a standard thread such as 8-32 NC. While these commercially available fasteners are intended for use with sheet metal, not plastic, they have been found to be quite suitable for use in the application described here.
Locator projections 260 are provided at spaced locations along the side walls 236, 238 at junctures of the side walls 236, 238 with the rear face 206 of the mounting flange 202. As will be seen in FIG. 7, the locator projections 260 are arranged symmetrically in pairs on opposite sides of the center plane 201. The locator projections 260 are intended to directly engage opposite sides 126, 128 of the opening 112 (see FIG. 1) to orient the lock assembly 100 properly on the closure 110; however, if the opening 112 has been formed so as to be slightly "oversized," the locator projections 260 may be utilized during installation of the lock assembly 100 on the closure 110 as "guides" to visually aid in properly positioning the housing 200 with respect to the closure opening 112, preferably with the locator projections 260 being arranged to be spaced substantially equidistantly from opposite side portions 126, 128 of the opening 112.
While the gasket 270 is not essential in many applications where the lock assembly 100 can be used, the gasket 270 preferably is used in applications that present a possibility that moisture may penetrate the opening 112 as by passing between the back face 206 of the mounting flange 202 and the front face 114 of the closure 110. To aid in properly positioning the gasket 270 about the lock assembly 100, the gasket 270 has an asymmetrical configuration that causes the gasket 270 to extend in an obviously skew, out-of-alignment relationship with respect to the edge portions 226, 228 of the mounting flange 202 if the gasket 270 is installed incorrectly, e.g., in an "inside-out" manner. Specifically, referring to FIGS. 1 and 2, the gasket 270 has a relatively wide left side portion 276 that underlies the relatively wide left side wall 236; similarly, the gasket 270 has a relatively narrow right side portion 278 that underlies the relatively narrow right side wall 238. Further, the gasket 270 has a relatively large corner region 272 that is configured to underlie a correspondingly large corner portion of the bottom wall 214 of the mounting flange 202, and a relatively smaller corner region 274 that is configured to underlie a correspondingly smaller corner portion of the bottom wall 214 of the mounting flange. The character of the cut-out 275 that is defined by the gasket 270 is configured to permit the gasket 270 to suitably surround rearwardly projecting portions of the housing 200.
Referring to FIGS. 2 and 15, the sleeve-like formation 280 of the housing 200 is located below the recess 210 and extends rearwardly from the rear face 206 of the mounting flange 202 along the bottom wall 234 of the housing portion 220. In preferred practice, the sleeve formation 280 is provided on the housing 200 regardless of whether the sleeve formation 280 is to be utilized to house operating components of a latch or lock.
If the sleeve formation 280 is to be utilized to house latch or lock components, an opening 282 is formed through the front wall 204 to communicate with a passage 284 that extends through the sleeve formation 280. The opening 282 and the passage 284 extend coaxially along an imaginary axis 281 that lies within the imaginary center plane 201 (see FIG. 7) and that extends substantially perpendicular to the planes of the rear face 206 and the back wall 246. If the sleeve formation 280 is not to be utilized to house latch or lock components, either no opening 282 is formed through the front wall 204, or a suitably configured plug (not shown) is installed in the opening 282 to close the opening 282.
In FIGS. 15 and 19, features of the sleeve formation 280 are shown on an enlarged scale. Referring to FIG. 15, at a location near the forward end region of the passage 284, a shoulder 286 extends substantially radially with respect to the axis 281 to form a transition between a relatively large diameter front end region 283 of the passage 284 (which defines the opening 282) and a relatively smaller diameter central portion 285 of the passage 284. Axially extending top and bottom grooves 288 are formed in opposed upper and lower portions of the passage 284. The grooves 288 extend axially rearwardly from the shoulder 286 and have bottom walls 289 that are curved and represent continuations of a cylindrical surface 290 (see also FIG. 19) of enlarged diameter that is formed in the rearward end region of the sleeve 280.
Referring to FIG. 19, a radially extending shoulder 292 forms a transition between the reduced diameter of the central passage 285 and the enlarged diameter of the rearward end region 290. The shoulder 292 provides a circumferentially extending "end wall" that is located near the rearward end region of the sleeve formation 280. As will be explained later, the end wall 292 is engaged by and cooperates with a a retaining clip 680 to secure a rotary plug (such as the key cylinder 650) in the passage 284. While two opposed portions 296, 298 of the shoulder 292 extend radially outwardly and interrupt opposed side portions of the sleeve formation 280, these features are not made use of in the preferred practice of the present invention (however, these features are utilized in the preferred practice of the invention that forms the subject matter of the referenced Predecessor Case).
Referring to FIGS. 1, 2, and 3, it will be understood that, in preferred practice, the housing 200 is formed without any openings, holes, slots or the like extending through the walls that define the recess 210, i.e., the top, bottom, and side walls 232, 234, 236, 238, and the back wall 242 are smooth and have no openings formed therethrough. Depending on the type of handle that is to be used with the housing 200, and on the type of latch or lock operating mechanism that is to be mounted on the housing 200, one or more suitable passages (such as a back wall opening 322 depicted in FIGS. 11-13) through the housing 200 are machined to provide openings, holes, slots and the like, as may be needed, which formed as by drilling, milling or other conventional machining techniques.
Referring to FIGS. 2 and 13, the handle assembly 300 includes a forward component 301 and a rearward component 302 that are formed from molded plastics material, preferably of the same thermoplastics material from which the housing 200 is formed. The forward component 301 defines forwardmost portions of the handle assembly 300. The rearward component 303 abuttingly engages the forward component 301 and is rigidly connected to the forward component 301, as will be explained. By utilizing the two separately molded components 301, 303 to form the basic structure of the handle 300 (which is in contrast to the single component that is utilized to form a handle of very similar configuration for use with the invention embodiment that is described in the referenced Predecessor Case), the relatively complex shape of the handle 300 is rendered easier to mold.
The forward handle component 301 has a front surface 304 that is of complexly curved, generally convex shape, and is configured to extend in a flush, substantially contiguous manner to smoothly continue the curvature of the complexly curved, convex front surface 204 of the mounting flange 202 when the handle assembly 300 is in its normal or nested position. The handle component 301 has a back wall surface 306. As is best seen in FIG. 13, four projecting formations 310 extend rearwardly from the back wall surface 306 at spaced intervals therealong, with a central pair of the formations 310 defining a space therebetween that snugly receives the rearward handle component 303. The rearward handle component 303 has a front surface 305 (see FIG. 2) that abuttingly engages the back wall surface 306 of the forward handle component 301.
Aligned holes 312 are formed through the rearwardly projecting formations 310 of the forward component 301, and through the forward end region of the rearward component 303 to receive a mounting pin 350. The mounting pin 350 extends through the aligned holes 312 in a slip fit that enables the handle components 301, 303 to pivot as a unit about the axis of the pin 350. By this arrangement, the pin 350 serves the dual functions of rigidly interconnecting the handle components 301, 303, and of mounting the handle components 301, 303 for pivotal movement relative to the pin 350 about the axis of the pin 350.
Referring to FIGS. 2 and 13, the mounting pin 350 preferably is formed from stainless steel stock, and has opposed end regions 351, 353 that are received in aligned holes 352 (one is shown in FIG. 2) that are formed in the end walls 232, 234 of the housing 200. The end region 351 is provided with a plurality of raised rib-like flutes 355 that are configured to seat tightly in one of the housing holes 352 so as to retain the mounting pin 350 in place so that the mounting pin 350 neither moves axially nor rotates relative to the housing 200. By this arrangement, the mounting pin 350 supports the handle components 301, 303 for pivotal movement relative to the housing 200 between a normally nested position that is, shown in FIGS. 1, 5-9, 11 and 13 and an operating position that is depicted in FIGS. 10 and 12. As is depicted in the drawings, the forward component 301 of the handle assembly 300 has a generally rectangular shape and a size that lets the component 301 nest and move with ease within the confines of the recess 210.
The rearward component 303 has a rearwardly extending projection 320 that is of substantially elliptical cross section and that extends through an opening 322 that is formed in the back wall 242 of the housing 200. When the handle assembly 300 is in its nested position, the projection 320 extends substantially centrally through the opening 322, as is shown in FIG. 11. When the handle assembly 300 is in its operated position, the projection 320 resides near to (but is spaced from) one side of the opening 322, as is shown in FIG. 12. By this arrangement, central portions 902 of a resilient boot type seal 900 can extend into the opening 322 and into surrounding relationship with the projection 320 to form a weather resistant seal between the housing 200 and the handle assembly 300 and to thereby prevent the passage of unwanted moisture through the opening 322. For purposes of receiving and matingly engaging central portions 902 of the boot 900, a perimetrically extending groove 321 is formed about the projection 320. An additional groove 323 of a V-shaped type extends across one side of the projection 320 at a location that is rearward with respect to the location of the groove 321 to provide clearance for proper side to side movement of the projection 320 as the handle assembly 300 is pivoted between its nested and operated positions.
Referring to FIGS. 2, 11 and 12, the resilient boot type seal 900 has a flat, generally rectangular rim portion 904 that surrounds the more bulbous central portion 902. A pair of holes 906 are formed through opposed corner regions of the rim portion 904. A generally elliptical opening 908 is formed through the central portion 902 to receive and sealingly mate with the projection 320. As is best seen in FIGS. 11 and 12, an enlarged rib 310 defines the opening 308 and extends snugly into the groove 321. The boot seal 900 preferably is formed as a water impervious membrane of a resilient material such as ethylene propylene having a thickness of at least about 0.025 inches and a durometer of about 80. The rim portion 904 of the boot seal 900 is clamped between the back wall 242 of the housing 200 and overlying portions of a mounting plate 520 to hold the boot seal 900 in place, as will be explained.
A compression coil spring 360 (see FIG. 2) is interposed between the back surface 306 and the back wall 242. One end region of the spring 360 is wrapped tightly about a projection 362 (see FIG. 13) that extends rearwardly from the back surface 306. The spring 360 biases the handle assembly 300 toward its nested position.
As is best seen in FIGS. 11 and 12, the handle projection 320 has an end portion 370 that is engageable with the bolt 400 either to retain the bolt 400 latched (as is shown in FIG. 11) or to release the bolt 400 for movement to is unlatched position (shown in FIG. 12).
The latch bolt 400 is connected to the housing 200 by means of mounting plate and spring assembly 500 that is mounted on the back wall 242 of the housing 200 by the mounting posts 700. The latch bolt 400 is movable between a latched position (shown in FIGS. 1, 5-9 and 11) and an unlatched position (shown in FIGS. 10 and 12).
Referring to FIGS. 2, 11 and 12, the latch bolt 400 is an elongate member of generally rectangular configuration having a left end region 406 that is engageable, with the handle projection 320, a right end region 404 that is engageable with the striker surfaces 188, 198, and a central region 410 that interconnects and extends between the end regions 404, 406. A pair of mounting formations 412 are provided on the central region 410. The mounting formations 412 border opposite sides of a slot 414 that is formed through the mounting plate within which a torsion coil spring 510 is carried.
Referring to FIG. 2, the torsion coil spring 510 and the mounting plate 520 are connected to the latch bolt 400 by means of a pivot pin 530. The pivot pin 530 extends through aligned holes 418 formed in the mounting formations 412, through coils of the spring 510, and through aligned holes 542 that are provided in a pair of upstanding mounts 540 that are formed integrally with the mounting plate 520.
The mounting plate 520 preferably is formed from the same thermoplastic material that is used to form the housing 200 and the handle assembly 300. The mounting plate 520 has a rim 521 that is configured to be clamped into engagement with the back wall 242 of the housing 200. The rim 521 surrounds a forwardly facing wall 523 and cooperates with the wall 523 to define a recess that is configured to receive the rim portion 904 of the boot seal 900. Holes 522 are formed through the wall 523 to receive the threaded studs 250. The mounting posts 700 have cylindrical portions 703 that extend for a short distance into enlarged rearward end regions of the holes 522 as the mounting posts 700 are threaded onto the studs 250 to clamp the mounting plate 520 in place on the housing 200 (and to thereby clamp the rim portion 904 of the boot seal 900 between the wall surfaces 523, 242 to hold the boot seal 900 in place.
Referring to FIG. 16, if no boot seal 900 is to be used with the lock assembly 100, a shim member 925 is provided to effectively fill the recess that is defined by the rim 521 and the wall 523. The shim member 925 has suitable holes 927 and a central opening 929 formed therethrough to receive the threaded studs 250 and the rearwardly extending handle projection 320.
Referring once again to FIG. 2, a passage 524 is formed through the central region of the mounting plate 520 in alignment with the back wall opening 322 to receive the handle projection 320. The torsion spring 510 has opposite ends 512, 514 in engagement with the mounting plate 520 and the bolt 400 to bias the bolt in the direction of the arrow 516 as shown in FIGS. 11 and 12. When the latch bolt 400 is in its latched position, the end 402 of the latch bolt 400 is engaged by the end 370 of the handle projection 320 and is thereby held securely in its latched position. When the handle assembly 300 is pivoted (as is shown in FIG. 12) to its operated position, the end 370 of the projection 320 disengages the latch bolt 400, and the latch bolt 400 pivots to its unlatched position under influence of the torsion coil spring 510. As the latch bolt 400 pivots to its latched position, the engagement between the latch bolt 400 and the striker surface 188 (see FIGS. 3-5) will cause the closure 110 to be forced open with something of a pop-open type of action.
Referring to FIGS. 2 and 7-10, the locking system 600 includes a locking member 640 that is slidably carried by the mounting plate 520 for movement between a locked position that is shown in FIGS. 7 and 8, and an unlocked position that is shown in FIGS. 9 and 10. Referring to FIGS. 2 and 20, the locking member 640 has a generally U-shaped base portion 641 that is connected by a dog-legged formation 643 to an elongate stem portion 642. The stem portion 642 is slidably carried in a slide channel 528 that is defined by an opening 529 that is formed through a raised portion 531 of the mounting plate 520 (see FIG. 2). When the locking system 600 is locked, the stem portion 612 of the stem portion 642 of the locking member 640 overlies a portion of the opening 524 (as is shown in FIG. 7) to prevent the handle projection 320 from moving out of its latched position. When the locking member 640 is moved to its unlocked position (shown in FIG. 9), the stem portion 642 no longer blocks movement of the handle projection 320 within the opening 524, and the handle assembly 300 therefor can be operated to effect unlatching movement of the latch bolt 400.
Referring to FIGS. 2 and 20, the base portion 641 of the locking member 640 has a central part 645 that overlies the rear end of the sleeve formation 280 of the housing 200, and a pair of opposed arms 647 that extend forwardly so as to embrace opposite sides of the sleeve formation 280 in a slip fit (as is best seen in FIG. 8). By this arrangement, the arms 647 cooperate with the sleeve formation 280 to help guide the movement of the locking member 640 between its locked and unlocked positions. Moreover, the embracing engagement that is provided by the arms 647 with the sleeve formation 280 enhances the secure locking action of the assembly 100 in that the locking member 640 is prevented from being forced out of position in a manner that might defeat its locking function.
An elongate slot 644 is formed in the base portion 641 of the locking member 640 to receive an offset projection 675 that is provided on the rearward end region of the key cylinder 650. By this arrangement, a driving connection is established between the key cylinder 650 and the locking member 640 that enables key cylinder 650, when rotated 180 degrees within the passage 284 of the sleeve formation 280 of the housing 200, to move the locking member 640 between its locked and unlocked positions. A comparison of the relative component positions depicted in FIGS. 7 and 9 shows how a 180 degree rotation of the key cylinder 650 is operative to effect locking and unlocking movements of the locking member 640.
Referring to FIGS. 2, 15, 18 and 19, the manner in which the key cylinder assembly 650 is installed in the housing opening and passage 282, 284 is to first install a washer-like ring 653 onto the body of the key cylinder assembly at a location near its enlarged forward end region 651, and thence to insert a leaf spring 950 and a retaining clip 952 into a groove 655 that is provided near the rearward end region of the key cylinder assembly. Referring to FIGS. 18 and 19, the groove 655 is configured to matingly receive the U-shaped retaining clip 952 with the leaf spring 950 interposed between a central portion 657 of the key cylinder and the retaining clip 952 to bias the retaining clip 952 radially outwardly with respect to the groove 655. By this arrangement, the retaining clip 952 can be depressed into the groove 655 in opposition to the action of the spring 950 to enable the key cylinder 650 to be inserted through the opening 282 into the central portion 285 of the passage 284; however, when the groove 655 passes rearwardly beyond the end wall 292 of the sleeve formation 280, the action of the spring 950 will force portions of the retaining clip 952 to move radially outwardly to the position illustrated in FIG. 19 so as to overlie portions of the end wall 292 and to thereby retain the key cylinder 650 within the passage 284. Those skilled in the art are familiar with this type of key cylinder retention system, for it is not novel and has been relatively widely utilized in a variety of commercially available lock embodiments.
Referring to FIG. 15, in place of the key cylinder assembly 650, it is possible to employ other forms of rotary plugs, such as the depicted plug members 800, 810. The plug members 800, 810 have substantially the same general shape as the key cylinder assembly 650 and therefore can be installed in the opening and passages 282, 284 to function like the key cylinder assembly 650 except that no key is required to effect their rotation. Instead, a tool receiving formation such as a hex driver receiving opening 820, or a flat groove 822 for receiving a screwdriver blade is provided in outer end regions of the plug members 800, 810 as is depicted in FIG. 15.
Ball detents 802, 812 can be provided in the plug members 800, 810 as by forming radially extending passages 804, 814 into which are inserted compression coil springs 806, 816 and balls 808, 818. The balls 808, 818 are operative to engage the grooves 288 to prevent unwanted rotary movement of the plugs 800, 810.
Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example, and that numerous changes in details of construction as well as the combination and arrangement of parts may be made without departing from the spirit and scope of the invention as hereinafter claimed. It is intended that the patent shall cover by suitable expression in the appended claims, whatever features of patentable novelty exist in the invention disclosed. | Flush mountable latches and locks for industrial cabinets, tool carts, electrical equipment enclosures and the like utilize versatile housings of novel configuration together with push-to-operate handles that are pivotally movable relative to the housings to effect unlatching movements of spring-biased, pivotally mounted latch bolts. The lock-type embodiment has a locking mechanism that is mounted on the housing to selectively permit and prevent unlatching movements of its pivotal latch bolt. The resulting arrangement provides sturdy latch and lock assemblies that employ a small number of relatively movable parts that can be assembled, installed and serviced with ease. Improved features include the provision of a plural part handle assembly having portions that are configured to cooperate with a resilient, weather resistant boot that optionally may be interposed between housing and handle assembly components. Other improvements features include the provision of mounting hardware that readily adapts latch and lock units for mounting on structures of a wide variety of thicknesses, and simplifications that enhance the ease of assembly and improve the operation of components that are employed in the lock-type embodiment. |
RELATED APPLICATIONS
[0001] The present invention claims the benefit of prior-filed, co-pending U.S. provisional patent application Ser. No. 60/956,855, filed Aug. 20, 2007, the entire contents of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to cutting tools and, more particularly, to a rotary cutting tool for a power tool.
SUMMARY
[0003] In some embodiments, the present invention provides a kit including a cutting tool for use with a power tool for cutting a workpiece. The cutting tool can include a universal shaft and a cutting bit, both of which can have a first end and a second end and define a longitudinal axis extending through the respective first and second ends. The cutting tool can be assembled by connecting the universal shaft and cutting bit, aligning the axes of the universal shaft and the cutting bit, and using a locking assembly to secure the cutting bit to the universal shaft. In some embodiments, the locking assembly can be located on the universal shaft. In other embodiments, the locking assembly can be located on the cutting bit.
[0004] The present invention also provides a housing for a cutting tool which can include a universal shaft and a cutting bit. The cutting tool can be assembled by connecting the universal shaft to the cutting bit using a locking assembly. The universal shaft and cutting bit can be secured in the housing by a connecting structure, which can be formed around or partially engage the cutting tool and/or the universal shaft.
[0005] The present invention also provides a rotary cutting system for releasable connection to a power tool, the power tool including a housing, a motor supported in the housing and a drive mechanism driven by the motor. The rotary cutting system comprises a universal shaft having a first shaft end and a second shaft end positioned opposite the first shaft end, the first shaft end being removably securable to the power tool, and a cutting tool having a first tool end, and a second tool end spaced a distance of no more than inches from the first tool end and operable to cut a workpiece, the first tool end being removably securable to the second shaft end of the universal shaft.
[0006] The present invention also provides a rotary cutting tool kit. The rotary cutting tool kit comprises a universal shaft being removably securable to a power tool, and at least two differently sized cutting tools operable to cut differently sized holes in a workpiece when driven by the power tool, wherein a length of the universal shaft between a first shaft end, which is removably securable to a power tool, and a second shaft end is greater than a length of each of the at least two differently sized cutting tools between cutting edges and first tool ends, each of which is selectively securable to the universal shaft.
[0007] The present invention also provides a method of configuring a rotary cutting tool to cut at least two differently sized holes. The method comprises operating a power tool including a drive mechanism driven by a motor supported in a housing of the power tool, securing a first shaft end of a universal shaft to the drive mechanism, securing a first cutting tool to a second shaft end of the universal shaft opposite the first shaft end of the universal shaft, the first cutting tool being operable to cut one of the at least two differently sized holes and having a length between a cutting edge and a universal shaft-engaging end of less than a length of the universal shaft between the first and second shaft ends, removing the first cutting tool from the universal shaft, and securing a second cutting tool with a differently sized cutting head to that of the first cutting tool, the second cutting tool being operable to cut another of the at least two differently sized holes.
[0008] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a front view of a cutting tool and a cutting tool kit according to some embodiments of the present invention.
[0010] FIG. 1A illustrates a first portion of a cutting tool according to FIG. 1 .
[0011] FIG. 1B illustrates another portion of a cutting tool according to FIG. 1 .
[0012] FIG. 2 is a front view of a cutting tool kit according to an alternate embodiment of the present invention.
[0013] FIG. 3 is a front view of an interior of the cutting tool kit shown in FIG. 2 .
[0014] FIG. 4 is another front view of the interior of the cutting tool kit shown in FIG. 2 .
[0015] FIG. 5 is a front view of an exterior of the cutting tool kit shown in FIG. 2 .
[0016] FIG. 5A is another front view of an interior of the cutting tool kit shown in FIG. 2 .
[0017] FIG. 5B is another exterior view of the cutting tool kit shown in FIG. 2 .
[0018] FIG. 5C is a front perspective view of the cutting tool kit shown in FIG. 2 .
[0019] FIG. 6 is a front view of a cutting tool kit according to another alternate embodiment of the present invention.
DETAILED DESCRIPTION
[0020] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” and “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.
[0021] Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
[0022] In addition, it is to be understood that phraseology and terminology used herein with reference to device or element orientation (such as, for example, terms like “front,” “rear,” “top,” “bottom,” “lower”, “up,” “down,” etc.) are only used to simplify description of the present invention, and do not alone indicate or imply that the device or element referred to must have a particular orientation. The elements of the present invention can be installed and operated in any orientation desired. In addition, terms such as “first”, “second,” and “third” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance.
[0023] FIG. 1 illustrates a cutting tool kit 10 including a cutting tool 12 , such as, for example, a flat boring bit, for operation with a power tool having a motor (e.g. a drill, a driver drill, a screwdriver, a hammer drill, and the like) and engageable with a chuck. In some embodiments, the cutting tool 12 is operable to cut holes in a workpiece. In other embodiments and as described in greater detail below, the cutting tool 12 can also or alternatively be operable to drive fasteners (e.g., screws and other threaded and unthreaded fasteners) into a workpiece.
[0024] As shown in FIG. 1A , the cutting tool 12 includes a universal shaft 14 having a first end 16 and a second end 18 , and a longitudinal axis 20 extending through the first end 16 and the second end 18 . The first end 16 can be engaged with the front end and/or with the chuck of a power tool. In the illustrated embodiment, at least a portion of the universal shaft 14 has a substantially circular cross-sectional shape. In other embodiments, the universal shaft 14 can be of and/or can include portions having other cross-sectional shapes, such as, for example, D-shaped, square, rectangular, triangular, hexagonal, any polygonal other shape, irregular, or the like. The universal shaft 14 can also or alternatively have varying lengths measured from the first end 16 to the second end 18 , and can include telescoping members for adjusting the length of the universal shaft 14 between the first and second ends 16 , 18 .
[0025] As shown in FIG. 1A , the universal shaft 14 can include a locking assembly 28 . In the illustrated embodiment of FIG. 1 , the locking assembly 28 is located adjacent to the second end 18 . In some embodiments of the present invention, the locking assembly 28 can include an actuator 30 which is movable between locking (not shown) and unlocking positions (shown in FIG. 1 ). The actuator 30 can include a collar 32 moveable relative to the universal shaft 14 (e.g., rotatable about the longitudinal axis 20 , slidable along the universal shaft 14 , threaded to the shaft 14 , or a combination of such motions) to move a locking element (not shown) (e.g., a cam, a pin, a roller, a ball, a ramp-shaped protrusion, etc.) into locking engagement with a tool 50 supported in the second end 18 of the universal shaft 14 .
[0026] During operation, the actuator 30 can be moved relative to the universal shaft 14 toward the locking position such that the actuator 30 or a portion of the actuator 30 moves the locking member into locking engagement with the tool 50 supported in the second end 18 of the universal shaft 14 . In some embodiments, the locking assembly 28 can include a biasing member (e.g., a spring or another elastic element) for biasing the actuator 30 toward the locking position, or alternatively, for biasing the locking element toward a position in which the locking element is lockingly engageable with a tool 50 supported in universal shaft 14 . When the actuator 30 is moved toward the unlocking position, the actuator 30 can be operable to move the locking element out of engagement with the tool 50 supported in the second end 18 of the universal shaft 14 , or alternatively, to move out of engagement with the locking member such that the tool 50 can be moved out of the second end 18 of the universal shaft 14 .
[0027] As illustrated in FIG. 1B , the cutting tool 12 can include a number of differently configured tools 50 , each of which can have a first end 52 , a second end 54 , and a longitudinal axis 55 extending through the first end 52 and the second end 54 . In the illustrated embodiments, each of the tools 50 have a substantially flat head 56 and a driving shaft 58 located at the first end 52 and engageable with the locking assembly 28 on the universal shaft 14 . The second end 54 of each of the tools 50 can include a locating tip 60 and cutting blades 62 , which can be used to bore into a workpiece. The heads 56 of the tools 50 extend between the tip 60 and the cutting blades 62 and the driving shaft 58 .
[0028] In the illustrated embodiment of FIG. 1 , the tools 50 each have a spade-bit configuration for cutting holes of different sizes through a workpiece (e.g., wood, plastic, or other building materials). In other embodiments, one or more of the tools 50 can have a second end 54 shaped as a twist bit, an auger bit, a router bit, and the like for cutting differently shaped holes in a workpiece, or alternatively, for cutting through different workpieces. In still other embodiments, one or more of the tools 50 can have a second end shaped as a fastener driver and engageable with a fastener, such as, for example, a flathead screw, a Philips head screw, a Torx head screw, an Allen head screw, or the like for driving the fastener into a workpiece.
[0029] In the illustrated embodiment of FIG. 1 , each tool 50 has a shortened driving shaft 58 such that a number of tools 50 can be packaged together in the kit 10 . In other embodiments, the driving shaft 58 of one or more of the tools 50 can have a different length or a varying length, or alternatively, can have a telescoping construction to provide an adjustable length between first and second ends 52 , 54 . As shown in Table 1 and FIG. 1 B, the tool 50 can have a number of different widths W and lengths L. Alternatively or in addition, the kit 10 can include a number of differently sized tools 50 , each of which can have a different width W. In some such embodiments, two or more of the different tools 50 can have the same length L.
[0030] The width W is measured perpendicularly across the head 56 of the tool 50 , from one side to the other. The length L is measured along the longitudinal axis 55 of the tool 50 from the tip 60 to the end of the driving shaft 58 at the first end 52 . For example, an exemplary tool 50 (i.e., the tool 50 identified in Table 1 as “Flat Boring Bit ½×3.5”) has a width W of ½ inch and a length L of 3½ inches.
[0031] In the embodiment illustrated in FIG. 1 , the locking assembly 28 is located on the universal shaft 14 to couple the universal shaft 14 to each of the tools 50 . In other embodiments, the locking assembly 28 or a portion of the locking assembly 28 can be located on each of the tools 50 to couple the tools 50 to the universal shaft 14 . Additionally, the locking assembly 28 can include other locking mechanisms, such as, for example, a magnet for securing the tools 50 to the universal shaft 14 .
[0032] As shown in FIG. 1 , the cutting tool kit 10 can include a package 80 for housing and/or displaying the universal shaft 14 and the tools 50 . In some embodiments, the package 80 can include a clamshell housing formed around the cutting tool 12 and a connecting structure 82 for supporting the tools 50 and the universal shaft 14 in the package 80 . The cutting tool 12 can be secured to the package 80 by the connecting structure 82 . In the illustrated embodiment, the connecting structure 82 includes a number of sleeves 84 (i.e., a first connecting structure) for securing the tools 50 to the package 80 and a shaft sleeve 85 (i.e., a second connecting structure) for securing the universal shaft 14 to the package 80 . The sleeves 84 , 85 are sized to receive and removably secure the tools 50 and the universal shaft 14 . In additional embodiments, the cutting tool 12 can be secured or held in the package 80 by other connecting structures 82 such as, for example, straps, magnets, hook and loop fasteners, latching structures, elastic material, snaps, or the like.
[0033] In some embodiments, such as the embodiment illustrated in FIG. 1 , the connecting structure 82 in the kit 10 can support one or more cutting tools 12 . In some embodiments, the connecting structure 82 can also be T-shaped, linear, elongated, sized to engage cutting tools 12 , of varying size, organized in a graduated arrangement, or the like, or any combination thereof.
[0034] During operation, an operator removes the universal shaft 14 and the tool 50 from the package 80 by releasing them from the connecting structure 82 . The operator then assembles the cutting tool 12 by aligning the longitudinal axis 20 of the universal shaft 14 with the longitudinal axis 55 of the tool 50 and moving the actuator 30 from the unlocking position toward the locked position to secure the tool 50 to the universal shaft 14 . The operator then secures the first end 16 of the universal shaft 14 to the chuck of a power tool and positions the assembled cutting tool 12 above the workpiece with the center of the tip 60 located above the intended cutting location. The operator then activates the power tool to rotate the cutting tool 12 about the longitudinal axis 20 . As the cutting tool 12 rotates, the tip 60 drills a locating hole in the workpiece. Continued forward movement of the cutting tool 12 moves the cutting blades 62 into engagement with the workpiece. After use with the power tool is complete, the operator removes the cutting tool 12 from the power tool chuck, or alternatively, removes the tool 50 from the universal shaft 14 so that a different tool 50 can be secured to the universal shaft 14 .
[0035] The operator disassembles the cutting tool 12 by moving the actuator 30 of the locking assembly 28 toward the unlocking position so that the locking member is moved out of engagement with the tool 50 supported in the second end 18 of the universal shaft 14 . The operator can then remove the tool 50 from the universal shaft 14 . The operator then replaces the tool 50 and the universal shaft 14 in the package 80 by engaging the tool 50 and the universal shaft 14 with the connecting structure 82 for storage.
[0036] FIGS. 2-5 illustrate an alternate embodiment of a cutting tool kit 110 including a cutting tool 112 according to the present invention. The cutting tool kit 110 and the cutting tool 112 are similar in many ways to the illustrated embodiment of FIG. 1 described above. Accordingly, with the exception of mutually inconsistent features and elements between the embodiment of FIGS. 2-5 and the embodiment of FIG. 1 , reference is hereby made to the description above accompanying the embodiment of FIG. 1 for a more complete description of the features and elements (and the alternatives to the features and elements) of the embodiment of FIGS. 2-5 . Features and elements in the embodiment of FIGS. 2-5 corresponding to features and elements in the embodiment of FIG. 1 are numbered in the 100 series.
[0037] In the illustrated embodiment of FIGS. 2-5 , the cutting tool kit 110 includes a universal shaft 114 and a number of differently sized tools 150 supported in a reusable housing 180 having a connecting structure 182 for securing the universal shaft 114 and the tool 150 in the housing 180 . In the illustrated embodiment, the connecting structure 182 includes a number of sleeves 184 (i.e., a first connecting structure) for securing the tools 150 to the housing 180 and a shaft sleeve 185 (i.e., a second connecting structure) for securing the universal shaft 114 to the housing 180 . The sleeves 184 , 185 are sized to receive and removably secure the tools 150 and the universal shaft 114 . As shown in FIGS. 2-5 , the housing 180 can be formed of a supportive board structure covered with a layer of padding and a fabric outer cover. The outer cover can be of two or more colors and can be assembled to provide attractive designs, such as, for example, the hourglass-shaped design shown in FIGS. 2 and 5 , on the exterior of the housing 180 . In other embodiments, the housing 180 can be constructed with or without a supportive board, using an alternate type of supportive structure, or the like, with or without a layer of padding, using an alternate material for the outer cover, such as, for example, leather, plastic, rubber, or the like, or any combination thereof. In still other embodiments, the outer material of the housing 180 can be of one or more colors and can be assembled to form any alternate design.
[0038] As in the illustrated embodiment of FIGS. 2-5 , the housing 180 can include a first panel 186 a, a second panel 186 b, and a spine 186 c located between the first and second panels 186 a, 186 b. In some embodiments, the housing 180 can be collapsed into a storage and/or transport configuration such that the first and second panels 186 a, 186 b are folded inwardly toward a position in which the first and second panels 186 a, 186 b are substantially parallel and are adjacent, as illustrated in FIG. 5C . The housing 180 can also be moved toward an opened or display configuration, in which the first and second panels 186 a, 186 b are spaced apart and are generally coplanar, so that the contents of the housing 180 can be more easily accessed, as illustrated in FIGS. 5A and 5B .
[0039] The housing 180 can include a fastener 188 for securely closing the housing 180 . In the illustrated embodiment, the fastener 188 includes a fastening handle 188 a attached to an elastic or flexible cord 188 b, opposite ends of which can be secured to a first side (i.e., the first panel 186 a ) of the housing 180 . The fastener 188 can also include a pair of spaced apart locking protrusions 188 c extending outwardly from a second side (i.e., the second panel 186 b ) of the housing 180 . To lock the housing 180 in a closed position, the fastening handle 186 a is looped around and secured to the locking protrusions 188 c. In other embodiments, the housing 180 can include other fastening structures, such as, for example, snaps, zippers, hook and loop fasteners, elastic material, or the like, or no fastening structures at all.
[0040] In the illustrated embodiment in FIGS. 2-5 , the pocket housing 180 can include a storage pouch 192 located on an interior surface of one flap (e.g., the first flap 186 a, as shown in FIGS. 3 and 5 ) of the housing 180 . As shown in FIGS. 2-5 , the pouch 192 can include a zipper 193 for closing the pouch 192 . In other embodiments, the pouch 192 can include other or no closures, such as, for example, snaps, hook and loop fasteners, latching structures, elastic fasteners, or the like. In the illustrated embodiment, the pouch 192 is formed of a mesh material to provide visual access to the interior of the pouch 192 , but in other embodiments the pouch 192 can be made of another material, including, but not limited to, opaque, translucent, or transparent cloth, synthetic fabric, rubber, leather, plastic, and the like.
[0041] The pocket housing 180 can also include a belt clip 194 and a carrying handle 195 secured to respective interior and exterior sides of the spine 186 c of the housing 180 between the flaps 186 a, 186 b, as illustrated in the embodiment in FIGS. 2-5 , for ease of transport. In other embodiments, the pocket housing 180 can include other carrying structures, such as, for example, a hand grip, a strap, a tool belt loop, or the like, or any combination thereof, or no carrying structures at all.
[0042] FIG. 6 illustrates an alternate embodiment of a cutting tool kit 210 including a cutting tool 212 according to the present invention. The cutting tool kit 210 and the cutting tool 212 are similar in many ways to the illustrated embodiments of FIGS. 1-5C described above. Accordingly, with the exception of mutually inconsistent features and elements between the embodiment of FIG. 6 and the embodiments of FIGS. 1-5C , reference is hereby made to the description above accompanying the embodiments of FIGS. 1-5C for a more complete description of the features and elements (and the alternatives to the features and elements) of the embodiment of FIG. 6 . Features and elements in the embodiment of FIG. 6 corresponding to features and elements in the embodiments of FIGS. 1-5C are numbered in the 200 series.
[0043] FIG. 6 illustrates an alternate embodiment of the present invention including a kit 210 and a cutting tool 212 for use with a power tool for cutting a workpiece. The cutting tool 212 can include a universal shaft 214 and a tool 250 , both of which can have a first end 216 and 252 and a second end 218 and 254 , defining a longitudinal axis 220 and 255 extending through the respective first and second ends 216 and 252 , 218 and 254 , with the driving shaft 258 of the tool 250 being shortened in length L. The cutting tool 212 can be assembled by connecting the universal shaft 214 and tool 250 , aligning the axes 220 and 250 of the universal shaft 258 and the tool 250 , and using a locking assembly 228 to secure the tool 250 to the universal shaft 214 , as described above.
[0044] The embodiment of FIG. 6 provides a packaging structure 280 in the form of a display box. The display box 280 can hold one or more cutting tool kits 210 . In some embodiments, the display box 280 can include a holding structure 280 a and a lid 280 b. As illustrated, the holding structure 280 a can include a shortened side and an opposite unshortened side, with adjacent sides being sloped between the shortened to unshortened sides. In other embodiments, the display box holding structure 280 a can be constructed differently.
[0045] The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation up on the concepts and principles of the present invention.
[0000]
TABLE 1
W
L
DESCRIPTION
WIDTH
LENGTH
FLAT BORING BIT ½ × 3.5
½
3.5
FLAT BORING BIT ⅝ × 3.5
⅝
3.5
FLAT BORING BIT ¾ × 3.5
¾
3.5
FLAT BORING BIT ⅞ × 3.5
⅞
3.5
FLAT BORING BIT 1 × 3.5
1
3.5
FLAT BORING BIT 1¼ × 3.5
1¼
3.5
FLAT BORING BIT 1½ × 3.5
1½
3.5
FLAT BORING BIT ½ × 4
½
4
FLAT BORING BIT ⅝ × 4
⅝
4
FLAT BORING BIT ¾ × 4
¾
4
FLAT BORING BIT ⅞ × 4
⅞
4
FLAT BORING BIT 1 × 4
1
4
FLAT BORING BIT 1¼ × 4
1¼
4
FLAT BORING BIT 1½ × 4
1½
4
FLAT BORING BIT ⅜ × 16
⅜
16
FLAT BORING BIT ½ × 16
½
16
FLAT BORING BIT ⅝ × 16
⅝
16
FLAT BORING BIT ¾ × 16
¾
16
FLAT BORING BIT ⅞ × 16
⅞
16
FLAT BORING BIT 1 × 16
1
16
FLAT BORING BIT 15/16 × 3.5
15/16
3.5
FLAT BORING BIT 1⅛ × 3.5
1⅛
3.5
FLAT BORING BIT ¼ × 6.25
¼
6.25
FLAT BORING BIT 5/16 × 6.25
5/16
6.25
FLAT BORING BIT ⅜ × 6.25
⅜
6.25
FLAT BORING BIT 7/16 × 6.25
7/16
6.25
FLAT BORING BIT ½ × 6.25
½
6.25
FLAT BORING BIT 9/16 × 6.25
9/16
6.25
FLAT BORING BIT ⅝ × 6.25
⅝
6.25
FLAT BORING BIT 11/16 × 6.25
11/16
6.25
FLAT BORING BIT ¾ × 6.25
¾
6.25
FLAT BORING BIT 13/16 × 6.25
13/16
6.25
FLAT BORING BIT ⅞ × 6.25
⅞
6.25
FLAT BORING BIT 15/16 × 6.25
15/16
6.25
FLAT BORING BIT 1 × 6.25
1
6.25
FLAT BORING BIT 1⅛ × 6.25
1⅛
6.25
FLAT BORING BIT 1¼ × 6.25
1¼
6.25
FLAT BORING BIT 1⅜ × 6.25
1⅜
6.25
FLAT BORING BIT 1½ × 6.25
1½
6.25 | A rotary cutting system for releasable connection to a power tool, the power tool including a housing, a motor supported in the housing and a drive mechanism driven by the motor, the rotary cutting system comprising a universal shaft having a first shaft end and a second shaft end positioned opposite the first shaft end, the first shaft end being removably securable to the power tool, and a cutting tool having a first tool end, and a second tool end spaced a distance of at least 3.5 inches from the first tool end and operable to cut a workpiece, the first tool end being removably securable to the second shaft end of the universal shaft. |
BACKGROUND OF THE INVENTION
The present invention relates to a superconductor used in superconducting magnets for nuclear fusion research and the like, and in particular relates to a superconductor of a type forced cooled with a coolant.
Recently, there have been proposed various superconducting coils which use the so-called "hollow" superconductor provided along its center with a coolant channel through which a coolant such as supercritical helium is forced to circulate, so that the superconductor is forcedly cooled from the inside. Typical examples such hollow superconductors are shown in FIGS. 1 to 3. In FIG. 1, superconducting filaments 1 are embedded in the walls of a stabilized member 2 of a rectangular section, made of copper and the like, which has a coolant channel 3 centrally formed through it. FIG. 2 illustrates another type of superconductor in which extremely fine multi-filamentary superconducting wires 4 are wound or twisted around the outer faces of a stabilized member 5 of the same material as in FIG. 1. In another type of superconductor shown in FIG. 3, there are provided four grooves 6 longitudinally formed in the outer faces of the stabilized member 7. Braided and worked superconducting wires 8 are fitted into and soldered to the grooves 6.
Superconducting magnets utilizing superconductors of such forced cooled types are advantageous in that they are uniformly cooled by forcedly circulating a coolant in the superconductor, in that consumption of the coolant is relatively small, and in that the magnetic coil is compact and high in mechanical strength. However, in these superconducting magnets, the superconducting wires are indirectly cooled through the stabilizing member, and hence the efficiency of cooling is relatively low, which causes delay in recovery of superconducting state when it is lost due to a heat spot produced in the superconducting wires.
On the other hand, there has been proposed the so-called "bundle" type superconductor, as shown in FIG. 4, in which a great number of superconducting wires 9 are inserted into a square tube 10 and a coolant such as liquid helium flows the space 11 between the wires. In this superconductor the coolant comes into direct contact with the surfaces of the wires 9 and thereby direct cooling is performed. However, it is rather difficult to make the coolant smoothly flow through the superconductor, and local stay of the coolant is hence produced, resulting in an increase in temperature, which can cause a heat spot to be produced or a delay in recovery of the superconducting state.
In view of the above, it has been proposed in Japanese patent application No. 57-45795 filed Mar. 23, 1982, now Japanese Published Application No. 58-162008 published on Sept. 26, 1983 a superconductor into which advantageous structures of the hollow superconductors and the direct cooling type superconductor shown in FIG. 5 are incorporated. This superconductor has a structure which is excellent in overall cooling efficiency and local stability, and is further capable of withstanding relatively large electromagnetic force.
FIG. 5 shows a typical example of this prior art superconductor, in which a large number of superconducting wires 12 are accommodated in a hollow stabilizing member 13 having a rectangular cross section and made of an electrically highly conductive material at the cryogenic temperature such as copper, copper alloy, high purity aluminum, aluminum alloy, etc. The superconducting wires 12 are made of a superconducting alloy material, such as Nb-Ti alloy and Nb-Ti-Ta alloy, or an intermetallic superconducting material such as Nb 3 Sn, V 3 Ga, Nb 3 Ge, etc. The stabilizing member 13 is surrounded with a casing 14 of a rectangular tube made of copper, stainless steel, titanium alloy, etc. The stabilizing member 13 and the casing 14 are spaced by means of several separators 15 made of stainless steel or the same material as in the stabilizing member 13, and a coolant passage 16 is thereby formed between the stabilizing member 13 and the casing 14. The stabilizing member 13 has a plurality of passages 17 formed through it for flowing the coolant between the inside thereof and the coolant passage 16. The passages 16 may be in the form of a round hole, slot, slit or the like. A coolant, such as supercritical helium, which flows the coolant passages 16 passes through the passages 17 and enters into the space 18 formed between the superconducting wires 12 located inside the stabilizing member 13, where it comes into direct contact with the superconducting wires 12. Thus, a flow of the coolant is generated in the space 18 within the stabilizing member 13.
In the superconductor shown in FIG. 5, superconducting wire assemblies 19A and 19B consisting of a plurality of superconducting wires 12 are superposed with a thin tape 20 of a high resistance conductive material, such as cupronickel, interposed between them, and are accommodated in the stabilizing member 13. The tape 20 keeps the assemblies apart, and thereby prevents coupling current to flow between the assemblies, so that the deterioration in superconductivity characteristics of the superconductor at extremely high energizing speed, as in pulse drive, is prevented. Also, between each superconducting wire assembly and the stabilizing member 13, there is interposed a thin tape 21 similar to the tape 20. The tape 21 serves to prevent coupling current to flow the assemblies 19A and 19B through the stabilizing member 13. The tape 21 covering the superconducting wire assemblies 19A and 19B is provided with openings for allowing the coolant to pass through the passages 17 into the space 18 defined between the superconducting wires 12.
In this superconductor, the total cooling is carried out by a steady state flow of the coolant which flows the coolant passage 16, and thereby uniform cooling is carried out as in the previously-described prior art hollow superconductors. On the other hand, the direct cooling is made by bringing the coolant into direct contact with superconducting wires 12. Thus, this superconductor achieves fairly high cooling efficiency. It is to be noted that the coolant which flows outside and inside the atabilizing member is exchanged through the passages 17, and that there is hence little possibility of any heat spot is produced or the recovery of the superconducting state being delayed due to the local occurrence of a rise in temperature of the coolant as in the prior art direct-cooling-type superconductor in FIG. 4. Thus, the superconductor shown in FIG. 5 is superior also in stability in both the steady state and transient state. Further, this flow of the coolant through the passages 17 achieves sufficient cooling of the superconductor even when the superconducting wires have an assembly structure, such as a braided structure, which allows the coolant to flow less smoothly along the conductor. This fact gives less restriction to the design of the assembly structure of the superconducting wires. When in this superconductor the superconducting state is broken into the electrically normal conducting state due to a certain disturbance, part of the current flows into the stabilizing member, resulting in the production of heat. However, this heat of the stabilizing member is removed by the coolant which flows outside that member, and hence superconductor is capable of recovering the superconducting state soon as compared to the direct cooling system of the bundle type shown in FIG. 4. The superconductor is centrally provided with the superconducting wires, and hence when wound in a magnetic coil, it is less liable to be degraded in characteristics due to the bending stress.
The superconductor according to Japanese patent application No. 57-45795 is suitable for use in nuclear fusion reactors, electric machines, energy storage apparatus, magnetic resonance device, magnetic separation devices, etc., and particularly in large scale high magnetic field magnets. Further, it is particularly suitable for the superconductor carrying large pulse current.
However, in developing this superconductor for practical use, the inventors have found that it has disadvantages described below. Ordinarily, this kind of superconductor is wound in the shape of a coil into a superconducting magnet so that the edgewise sides C and D thereof are placed perpendicularly to the central axis O. The stabilizing member 13 is rather thick, and hence this superconductor is as a whole high in rigidity. Thus, it is rather difficult to wind it in a coil. In practice, the stabilizing member 13, as shown in FIGS. 7 and 8, consists of a channel member 22 and a planar member 23 fixedly fitted to the channel member 22, the channel member 22 forming the three sides 13A, 13B and 13C, and the planar member 23 the other flatwise side 13D. The planar member 23 is fixed to the channel member 22 by spot welding its contact edges in order to prevent the planar member 23 from falling within the channel member in the winding of a coil, resulting in providing a damage to the superconducting wires. However, this spot welding is laborious and time-consuming, and further the spot welded portions can be separated when the stabilizing member is bent by any unduely large force in the coil winding. FIGS. 9 and 10 show a similar stabilizing member 24 which is different from the stabilizing member 13 in FIGS. 7 and 8 in fitting flanges 26 and 27 extending along the opposite edges of the planar member 25. The planar member 25 is fixed to the channel member 28 with the free ends of the channel member being fitted to the shoulders of the fitting flanges 26 and 27. Also in this case, the channel member 28 and the planar member 25 are put together by spot welding.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a forced-cooled superconductor which facilitates the winding of a coil.
It is another object of the present invention to provide a forced-cooled superconductor which makes the use of the spot welding unnecessary in fabricating the stabilizing member and thereby simplifies the manufacture thereof.
It is a still other object of the present invention to provide a forced-cooled superconductor which withstands a relatively large electromagnetic force in the radial direction when wound in a pancake coil, so that the superconducting wires incorporated therein are less liable to be damaged or deteriorated due to the deformation or collapse of the stabilizer by the radial electromagnetic force.
It is a further object of the present invention to provide a forced-cooled superconductor which eliminates the possibility of one component of the stabilizing member being dropped into the other component during the winding of a coil, and thereby the superconducting wires are prevented from being damaged by the dropped component.
With these and other objects in view, the present invention provides a forced-cooled superconductor wherein a plurality of superconducting wires are placed within a hollow stabilizer of substantially rectangular section; and a first passage for passing a coolant is longitudinally formed between the stabilizer and a casing encasing the stabilizer, the stabilizer having a plurality of second passages formed therethrough for flowing the coolant from the first passage to the inside of the stabilizer so that the coolant flows through the second passages into the space defined between the superconducting wires for direct cooling. The stabilizer includes a pair of channel members opposedly fitted together to form into a substantially rectangular tube.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a cross section of a typical example of a prior art hollow superconductor;
FIG. 2 illustrates a cross-sectional view of another example of a prior art hollow superconductor;
FIG. 3 shows a cross-sectional view of a further example of a prior art hollow superconductor;
FIG. 4 illustrates a typical example of a prior art direct cooling type superconductor in a cross section;
FIG. 5 is a perspective view partly in section showing a further typical example of a prior art superconductor;
FIG. 6 is a fragmentary perspective view showing a prior art superconductor wound in a coil;
FIG. 7 is an exploded view of the stabilizing member of the prior art superconductor shown in FIG. 5;
FIG. 8 is a perspective view of the stabilizing member of the prior art superconductor shown in FIG. 5;
FIG. 9 is an exploded view of another stabilizing member used in the prior art superconductor of FIG. 5;
FIG. 10 illustrates a perspective view assembled view of the prior art stabilizing member shown in FIG. 9;
FIG. 11 illustrates a perspective view of a stabilizing member used in the superconductor according to the present invention;
FIG. 12 illustrates a perspective view of the stabilizing member in FIG. 11 wound in a coil;
FIG. 13 shows a perspective view of a modified form of the stabilizer in FIG. 11; and
FIG. 14 illustrates a perspective view of the superconductor adopting a stabilizer constructed according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the following description of the preferred embodiments of the present invention, reference is made to only the stabilizer of the superconductor since the structure and the members, except the stabilizer of the superconductor, disclosed in the aforementioned Japanese patent application No. 57-45795 are also adopted in the present invention.
FIG. 11 illustrates a stabilizer 31 used in the superconductor according to the present invention. The stabilizer consists of a pair of channel, members 33 and 35 having one channel member 33 opposingly fitted into the other channel member 35. The channel members 33 and 35 are merely fitted together without being fixed to one another by means of spot welding and the like. As in the Japanese patent application No. 57-45795 the channel members 33 and 35 have a plurality of passages 41 formed at predetermined intervals through webs 43 and 45 thereof for establishing communication between the inside and the outside of stabilizer 31. The passage 41 may be of a round through hole as in FIG. 11, a slit or other like configurations.
The channel members 33 and 35 are longitudinally slidable relative to each other since they are merely fitted together and not fixed to one another. Thus, when the superconductor using the stabilizing member 31 is wound in a coil, the relative sliding movement of the channel members 33 and 35 will compensate for the necessary extension of the diametrically outwardly positioned channel member, and thereby the winding of the superconductor around a reel is easily carried out. In this superconductor, there is no problem, as in the superconductor shown in FIG. 8, in that one member 23 is dropped into the other 22 with the result that the superconducting wires 12 are damaged by the one member 23. Further, this superconductor makes spot welding unnecessary and hence the manufacture thereof is simplified. It is further to be noted that the flanges 37 and 37 of the one channel member 33 lie on the flanges 39 and 39 of the other 35 respectively, and thus the superconductor has double-walled upper and lower portions. When this superconductor is wound in the form of a pancake coil, the double-walled upper and lower portions thereof are, as shown in FIG. 12, located so as to be perpendicular to the central axis O of the coil and extend in radial planes. In this state the edge of each flange 37 of one channel member 33 abuts against the bottom of the other channel member 35. Therefore, the superconductor withstands fairly large electromagnetic force F which is radially applied to it when energized, and which tends to deform or collapse it, so that the superconducting wires encased in the stabilizer are effectively prevented from being damaged.
FIG. 13 illustrates a modified form of the stabilizer 31 shown in FIG. 11, in which a pair of the channel members 47 and 49 have a plurality of longitudinal ridges 51 formed integrally with their outer faces, the ridges being of a rectangular cross section. These ridges 51 correspond to the separators 15 shown in FIG. 5, and serve as shown in FIG. 14 to form coolant passages 53 between the stabilizer 31 and the casing 14. This superconductor does not need any separators 15, and hence the assembly thereof is largely simplified. The channel members 47 and 49 are further provided at their flanges 55 and 57 with a plurality of slits 59 formed transversely at predetermined intervals. These slits 59 make it easier to bend the superconductor in a coil, so that the coiling of the superconductor is facilitated. Thus, large-scale superconducting magnets which can generate high magnetic field of the order of 10 to 12T can be easily built.
Those skilled in the art will gain a further and better understanding of this invention from the following illustrative, but not limiting, example of the forced-cooled superconductor of this invention.
EXAMPLE
There were prepared superconducting wires including 7735 Nb 3 Sn filaments each having a cross-sectional ratio of copper to non-copper components being 0.83 and a niobium diffusion barrier. All these wires were subjected to twisting and diameter reduction to form a primary conductor of 1.4 mm diameter. Fifteen primary conductors were prepared in this manner and stranded to form a secondary conductor with a strand pitch of 100 mm.
On the other hand, a stabilizer similar to that shown in FIG. 13 was prepared in the following manner. An oxygen free copper tape 3.5 mm thick and 31.0 mm wide was rolled to produce a first deformed tape 1.0 mm thick and 31.0 mm wide, having seven ridges 1.5 mm in height formed, at predetermined intervals, integrally with one surface thereof. Similarly, a second deformed oxygen free copper tape 27 mm wide and 1.0 mm thick having the same three ridges formed, at predetermined intervals, integrally with the central portion of one face thereof. The first and the second tapes were formed into channel members so as to be fitted together to form a stabilizer shown in FIG. 14. This stabilizer was provided by die-cutting at their flanges with slits 2 mm in width formed at an interval of 10 mm and at their webs with a great number of pass through holes 41.
Two secondary conductors were prepared in the above-described manner and each wound with a cupronickel tape 0.1 mm thick and 20 mm wide having appropriate holes for allowing a coolant to flow into the secondary conductor. Thereafter, these two secondary conductors each consisting of 15 primary conductors and covered with the cupronickel tape were continuously inserted in two layers into the stabilizer composed of the two channel tapes to form a third conductor, which was then introduced into a casing of oxygen free copper during the continuous welding of the casing. This casing was thereafter subjected to diameter reduction by means of a roll and die to thereby produce a fourth conductor of a rectangular cross-section 13 mm×23 mm and of more than 100 m length. The completed conductor is illustrated in an enlarged cross-sectional view in FIG. 14.
The thus-produced fourth conductor was electrically insulated with a silica, quartz or alumina glass tape and then wound into a coil having an inner diameter 300 mm, outer diameter 600 mm and height about 50 mm. Eight coils were prepared in this manner and subjected to heat diffusion respectively at the atmosphere of nitrogen gas at 800° C. for 50 hours to form Nb 3 Sn. Then, a forced-cooled superconducting magnet was built by piling these eight coils.
The superconducting magnet thus prepared was tested under forced cooling in combination with an outer magnet which generated a magnetic field of 5T. The cooling was carried out by circulating supercritical helium through the inside of the superconductor. It was noted that the magnet carried a current of 18,000 A at 5.5 K in a central magnetic field of 10T. In view of the fact that a superconducting wire (the primary conductor) of 1.4 mm diameter carries a critical current of 920A at 4.2 K in a central magnetic field of 10T, this results show that the magnet had little degradation in the supercondutivity due to the coiling, and exhibited excellent characteristics. | A forced-cooled superconductor wherein a plurality of superconducting wires are placed within a hollow stabilizer of substantially rectangular section; and a first passage for passing a coolant is longitudinally formed between the stabilizer and a casing encasing the stabilizer, the stabilizer having a plurality of second passages formed therethrough for flowing the coolant from the first passage to the inside of the stabilizer so that the coolant flows through the second passages into the space defined between the superconducting wires for direct cooling. The stabilizer includes a pair of channel members opposedly fitted together to form into a substantially rectangular tube. |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part application of co-pending application Ser. No. 25,800 filed Apr. 2, 1979 by the present inventor for "Thermal Energy Conversion System Utilizing Expandites," now U.S. Pat. No. 4,214,449.
BACKGROUND OF THE INVENTION
The present invention generally pertains to thermal energy conversion systems and is particularly directed to an improvement in ocean thermal energy conversion systems.
In typical closed cycle ocean thermal energy conversion systems warm surface water is used to heat a working fluid with a low boiling point. Ammonia is a typical working fluid. The fluid is heated in a boiler. Vapor is then cooled by frigid water that is drawn up from deep in the ocean. The vapor condenses, and is pressurized and returned to the boiler; and the cycle is repeated.
Heretofore, it has been believed that ocean thermal energy conversion systems must be deployed in at least sub-tropical waters in order to obtain a large enough temperature differential within the ocean to provide a system that is sufficiently efficient to warrant commercial development.
Another concern with close-cycle ocean thermal energy conversion systems is the cost of heat exchangers that typically are used to transfers heat to the working fluid.
A concern with typical open cycle ocean thermal energy conversion systems is a requirement for bulky tanks having heavy walls so as to enable the sea water to be evaporated at a low pressure in relation to ambient or atmospheric pressure.
SUMMARY OF THE INVENTION
The present invention is a thermal energy conversion system and method for converting a relatively low temperature differential in fluids into a high pressure differential at a minimum of capital investment, cost and maintenance.
Although the present invention is particularly directed to an ocean thermal energy conversion system and method, it also is applicable to other types of thermal energy conversion systems and methods including those in which the surrounding fluid is other than water. The term "fluid" as used herein not only includes a gas or a liquid but also includes a slurry, a mist, a slush, bubbles, a foam and a suspension of solid particles within a gas or liquid.
The patent application of the present inventor cross-referenced herein is directed to a thermal energy conversion system which includes a mass of expandites that change density in response to changes in temperature at a given pressure to thereby change buoyancy with respect to a surrounding thermal fluid; a mass transport conduit circuit for introducing the expandites to a surrounding thermal fluid at different combinations of temperature and pressure and directing the expandites and surrounding thermal fluid in response to pressure differentials created by density changes and concomitant buoyancy changes of the expandites as the expandites are exposed to the surrounding thermal fluid at different combinations of pressure and temperature; and a transducer for converting the pressure of fluid transported by the circuit to a useful form of energy. Expandites are defined as substances that expand or contract when heated or cooled, thereby changing their density. Some expandites expand upon being heated, while others expand upon being cooled.
In the specific preferred embodiments described in such cross-referenced patent application, the expandites are separate objects encased in flexible coverings.
The present invention is directed to those embodiments of the thermal energy conversion system and method wherein the expandites are unencased fluids. The method of thermal energy conversion according to the present invention includes the steps of: (a) providing a mass of unencased fluid expandites in a mass transport conduit circuit at a first combination of temperature and pressure; (b) introducing a non-gaseous thermal fluid into the mass transport conduit circuit from a source external to the mass transport conduit circuit at a second combination of temperature and pressure; (c) combining the provided expandite mass with the introduced thermal fluid in a given conduit of the circuit to create an expandite-fluid mixture having a density at some place in the given conduit that is changed from the average proportional density of the expandite mass and the thermal fluid at their respective prevailing combination of temperature and pressure prior to such combination with each other to create a pressure differential that enhances the flow of the fluids contained within the circuit; (d) directing at least a portion of fluids contained within the circuit to flow vertically through a given portion of the conduit circuit to create a pressure differential in the given portion of the circuit in relation to the remainder of the conduit circuit to thereby enhance the flow of the fluids contained within the conduit circuit, and (e) converting the pressure of at least a part of the enhanced flow of the contained fluids through the conduit circuit into a useful form of energy. Step (a) includes the steps of: (f) separating from the expandite-fluid mixture, an expandite base which comprises at least a portion of the expandite mass; and (f') thermally conditioning the expandite base.
An expandite is a material (or combination of materials) circulated through the mass transport conduit circuit that changes density in response to a change in temperature at a given pressure. The expandite material may be a combination of materials that are chosen to provide a desired density at a given combination of temperature and pressure.
A thermal fluid is a fluid that is introduced from a source external to the mass transport conduit circuit at a temperature that is either substantially above or substantially below the temperature of the expandite prior to initial combination therewith.
Either, or both, of the thermal fluid and the expandite material may change phase as a result of the combination with each other. However, a phase change is not required.
The expandite and the thermal fluid are different materials that do not react with each other chemically, whereby their respective chemical compositions remain essentially unchanged upon their combination with one another in the preferred embodiment.
Additional features of the present invention are described in the description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWING
FIGS. 1 through 14 are schematic diagrams of different preferred embodiments of the system of the present invention.
In each figure, the system is shown in a vertical plane, wherein the upper portion of the system is shown in the upper portion of the view. In an OTEC system, the upper portion of the system typically is at or near the ocean surface.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, one preferred embodiment of the system of the present invention is an OTEC system having a turbine generator 10, and a mass transport conduit system including a warm water intake conduit 11; a cold water intake conduit 12; gravity separation tanks 13, 14, 15, 16, 17 and 18; pumps 19, 20, 21, 22, 23 and 24; outlet conduits 25, 26 and 27, injection nozzle systems 28 and 29, a heat exchange 30; vertical conduit sections 31, 32, 33, 34, 35, 36, 37, 38, 39 and 40; and separation tank outlet conduits 41, 42, 43, 44, 45 and 46.
In the system of FIG. 1, a mass of unencased expandites, such as liquid ethane, is provided in the conduit 44 at a first combination pressure and temperature, and a first thermal fluid, such as warm ocean water, is introduced into the circuit through the conduit 11 at a second combination of pressure and temperature. The expandite mass is injected through the nozzle system 28 into the vertical conduits 31 where it is combined with the warm ocean water to create a first expandite-fluid mixture that flows upward through the conduit section 31 in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination. Further, by directing the first expandite-fluid mixture vertically through the conduit section 31, a pressure differential is created in the conduit section 31 in relation to the remainder of the mass transport conduit circuit for drawing the mixture upward through the conduit section 31.
The first expandite-fluid mixture is directed from the conduit section 31 through a first series of gravity separation tanks 13, 14 and 15, for separating the first expandite-fluid-mixture into an expandite base and a separated first thermal fluid. Ethane gas is lighter than ocean water, and thereby may be drawn from the top of the gravity separation tanks 13, 14 and 15, whereas the ocean water may be drawn from the bottom of these tanks. Accordingly, some expandite base is drawn through conduit 41 from the gravity separation tank 13 and a diluted first expandite fluid-mixture which contains a greater proportion of thermal fluid is drawn-up through conduit section 32.
The first expandite-fluid mixture is passed through the series of gravity separation tanks 13, 14 and 15 to provide successively lower pressures for enabling separation from the first expandite-fluid mixture at successively lower pressures, of expandite base that was not separated at the higher pressures. Additional expandite base is separated from the mixture by the gravity separation tank 14 and is drawn therefrom through the conduit 42. The further diluted first expandite-fluid mixture is drawn from the separation tank 14 through vertical conduit 33.
The turbine generator 10 is positioned in the conduit 33 for converting the pressure of the flow of the first expandite-fluid mixture through the conduit 33 into a useful form of energy, such as electricity.
The pressure of the flow of the first mixture through the conduit 33 is greatly decreased upon the first mixture flowing through the turbine generator 10. As a result, the pressure of the first mixture flowing from conduit 33 into the separation tank 15 is at a relatively low pressure for enabling almost all of the remaining expandite base to be separated therefrom and drawn from the tank 15 through the conduit 43.
Also the tank is at or near the ocean surface, and thereby at an elevation where the ambient pressure outside the tank 15 is close to the pressure of the mixture inside the tank. By positioning the separation tanks 14 and 15 at depths (or elevations) which enable the gravity separation process to be carried out with the pressure of the first mixture close to or approximately the same as the ambient pressure, the walls of the tanks need not be very thick, thereby enabling the use of less expensive gravity separation tanks.
The pressure within the gravity separation tank 15 typically is below atmospheric pressure for enhancing the separation of the expandite from the first expandite fluid mixture.
The separated thermal fluid separated from the first mixture by the gravity separation tank 15 is discharged from the mass transport conduit circuit through the outlet conduit 26.
The separated expandite base drawn from the separation tanks 13, 14 and 15 is directed to the conduit 40, from which it is injected under pressure by the nozzle system 29 into a second thermal fluid, such as cold ocean water, within the conduit 34. The cold ocean water is introduced into the circuit through inlet conduit 12 at a third combination of temperature and pressure and is combined with the separated expandite base in the conduit 34 to form a second expandite-fluid mixture.
The second expandite-fluid mixture also is passed through a series of gravity separation tanks, to wit: tanks 16, 17 and 18. Expandite means is separated from the second expandite-fluid mixture in the gravity separation tank 16 and is directed through the conduit 44. By combining the expandite mass in the conduit 40 with the cold ocean water and then separating the resultant second expandite-fluid mixture, the expandite base is thermally conditioned (cooled) to provide the expandite mass at the first combination of pressure and temperature in the conduit 44. The pressure of the expandite mass in the conduit 44 may be increased by the pump 23 to increase the dispersal rate of the expandite mass into the ocean water to thereby increase the rate of the density change of the first expandite-fluid mixture. Also the expandite mass in the conduit 44 may be preheated by passing it through the heat exchanger 30, in which it is heated by some of the warm ocean water drawn into the circuit through the inlet conduit 11.
By preheating the expandite mass prior to combining it with the warm ocean water in the conduit 31, the density change in the first expandite-fluid mixture is increased. The warm ocean fluid that passed through the heat exchanger 30 is pumped by the pump 24 and discharged from the circuit through the outlet conduit 25.
The second expandite-fluid mixture is diluted by the separation of the expandite mass from the separation tank 16. The diluted second expandite-fluid mixture is drawn from the separation tank 16 through the vertical conduit 35 into the separation tank 17. Additional expandite is separated from the second expandite-fluid mixture in the separation tank 17 and drawn therefrom through the conduit 45. The further diluted second expandite-fluid mixture is directed upward through the vertical conduit 36 to a final separation tank 18, which is at or near the ocean surface. Almost all of the remaining expandite is separated from the second expandite-fluid mixture in the separation tank 18 and drawn therefrom through the conduit 46. The second thermal fluid that is separated from the expandite-fluid mixture in the separation tank 18 is discharged from the mass transport conduit circuit via the outlet conduit 27. The separated expandite drawn from the separation tanks 15 and 18 is drawn through the conduit 37 by the pump 19, is combined with the expandite drawn from the separation tank 17. This combination is drawn through the conduit 38 by the pump 20 and is combined with the expandite drawn from the separation tank 14. This combination is drawn through the conduit 39 by the pump 21 and is combined with the expandite base drawn from the separation tank 13 to provide the separated expandite base in the conduit 40 that is combined with the cold ocean water. The separated expandite base may be pumped through the conduit 40 by the pump 22 to be at an increased pressure when combined with the cold ocean water so as to increase the rate of dispersal to thereby increase the rate of cooling of the separated expandite base. The pumps 19, 20 and 21 also aid in increasing the pressure of the flow of the separated expandite base. The amount of added pressure that is provided by the pumps 19, 20, 21 and 22 is related to the pressure of the flow of the separated expandite base from the respective separation tanks 13, 14, 15, 17 and 18. These pumps consume negligible energy in relation to the energy converted by the system.
By separating expandite from the first and second expandite-fluid mixtures at the higher pressures prevailing within the gravity separation tanks 13, 14, 16 and 17 energy is saved, in that not as much pumping is required to increase the pressure of the separated expandite prior to combining it with the first and second thermal fluids respectively in vertical conduits 31 and 34.
The separation tanks 16, 17 and 18 are positioned at depths where the ambient pressure outside the tanks is close to or approximately the same as the pressure of the second expandite-fluid mixture within the tanks so as to enable the use of separation tanks having relatively thin walls. The pressure within the gravity separation tank 18 typically is below atmospheric pressure to enhance separation of the expandite from the second expandite-fluid mixture.
Pressure differentials are created in the respective vertical conduit sections 32, 33, 34, 35 and 36 in relation to the remainder of the conduit circuit for drawing the mixtures contained therein vertically upward through the respective conduit sections in the same manner as the first expandite-fluid mixture is drawn vertically upward through the vertical conduit section 31.
Alternatively, or in addition to the placement of the turbine generator 10 in the conduit 33, turbine generators (not shown) may be placed in the inlet conduit 11 to provide energy by converting the pressure of the flow of the warm ocean water drawn into the circuit; in the inlet conduit 12 to provide energy by converting the pressure of the flow of the cold ocean water drawn into the circuit; in the conduit 36 to provide energy by converting the pressure of the flow of the second expandite-fluid mixture; and/or in either or both of the outlet conduits 26 and 27 to convert the pressure of the flow of the separated thermal fluid. By placing the turbine generator in the inlet conduit 11, the pressure of the first thermal fluid is reduced, whereby the pressure of the first expandite-fluid mixture within the conduit 31 also is reduced. This enables the gravity separation tank 13 to be at an ocean depth where the pressure inside the tank is approximately the same as the ambient pressure.
The turbine generator must be positioned at a depth of the intake conduit 11 sufficient to provide a sufficient pressure differential across the turbine generator.
The warm water intake conduit 11 and the cold water intake conduit 12 draw ocean water from such respective depths as required to provide water at temperatures that are sufficiently different to create sufficient pressure differentials within the circuit to enable economical energy conversion.
When the expandite material has the property of becoming more dense when heated, the system shown in FIG. 1 can nevertheless be used if it is modified to reverse the connections of the warm water intake conduit 11 and the cold water intake conduit 12 to the remainder of the circuit. That is the conduit 11 is connected to the conduit 34 and the conduit 12 is connected to the conduit 31.
Other modifications of the system also will be obvious to those skilled in the art when using other expandite materials, such as modifying the system to combine the expandite mass with the first thermal fluid at an elevation at or near sea level and to direct the flow of the resulting expandite-fluid mixture vertically downward in response to the change in average proportional density in the mixture resulting from such combination.
Alternative preferred embodiments are shown in FIGS. 2 through 14. In these embodiments, generally only one separation tank is shown for each separation step. However, it should be understood that in actual practice, a cascaded series of separation tanks may be used, as described in relation to the system of FIG. 1.
The system of FIG. 2 includes two turbine generators 46 and 47 and a mass transport conduit circuit including a warm water inlet conduit 48, a cold water inlet conduit 49, gravity separation tanks 50 and 51, injection nozzle systems 52 and 53; outlet conduits 54 and 55; vertical conduits 56 and 57 and separation tank outlet conduits 58, 59, 60 and 61.
An expandite mass, such as nitrobenzene, is provided in the conduit 60 at a first combination of pressure and temperature and a first thermal fluid, such as warm ocean water, is introduced into the circuit through the conduit 48 at a second combination of pressure and temperature. The expandite mass is injected through the nozzle system 53 into the vertical conduit 57 where it is combined with the warm ocean water to create a first expandite-fluid mixture that flows downward through the conduit section 57 in response to the pressure differential created by the change in average proportional density of the first expandite fluid mixture resulting from such combination. Further by directing the first expandite-fluid mixture vertically through the conduit section 57, a pressure differential is created in the conduit section 57 in relation to the remainder of the mass transport conduit circuit for drawing the mixture downward through the conduit section 57.
The expandite fluid mixture is directed from the vertical conduit 57 into the gravity separation tank 51, where it is separated into a separated expandite base which flows out of the tank 51 through the conduit 58 and a separated first thermal fluid which flows out of the tank 51 through the conduit 59 is directed through the turbine generator 46, which converts the pressure of the flow to electricity. After flowing through the turbine generator 46, the separated first thermal fluid is discharged from the circuit through the conduit 54.
A second thermal fluid, such as cold ocean water, is introduced into the circuit through the conduit 49 at a third combination of pressure and temperature. The separated expandite base in conduit 58 is injected through the nozzle system 52 into the vertical conduit 56 where it is combined with the cold ocean water to create a second expandite-fluid mixture that flows upward through the conduit section 56 in response to the pressure differential created by the change in average proportional density of the second expandite-fluid mixture resulting from such combination. Further, by directing the second expandite-fluid mixture vertically through the conduit section 56, a pressure differential is created in the conduit section 56 in relation to the remainder of the mass transport conduit circuit for drawing the second mixture upward through the conduit section 56.
The second expandite fluid mixture is directed from the vertical conduit 56 into the gravity separation tank 50, where it is separated into the expandite mass at the first combination of temperature and pressure, which flows out of the tank 50 through the conduit 60, and a separated second thermal fluid, which flows out of the tank 50 through the conduit 61.
The separated second thermal fluid in the conduit 61 is directed through the turbine generator 47, which converts the pressure of the flow to electricity. After flowing through the turbine generator 47, the separated second thermal fluid is discharged from the circuit through the conduit 55.
By combining the separated expandite base with the cold ocean water, the separated expandite base was thermally conditioned to provide the expandite mass at the first combination of temperature and pressure in the conduit 60.
Both the turbine generators 46, 47 are located at or near the ocean surface in the system of FIG. 2. Turbine generators can be placed in the conduit sections 48, 49, 56, 57, 58 and/or 60 to convert the pressure of the flow in these portions of the circuit into electricity.
The system of FIG. 3 includes a turbine generator 63 and a mass transport conduit circuit including a warm water inlet conduit 64, a cold water inlet conduit 65, gravity separation tanks 66, 67 and 68, injection nozzle systems 69, 70, 71 and 72, outlet conduits 73 and 74, vertical conduit sections 75 and 76, conduit sections 77, 78, 79, 80, 81, 82, 82a and 83 and pumps 84 and 85.
An expandite mass, such as ethane is provided in the conduit 81 at a first combination of pressure and temperature, and a first thermal fluid, such as cold ocean water, is introduced into the circuit through the conduit 65 at a second combination of pressure and temperature. The expandite mass in the conduit 81 is injected through the nozzle system 70 into the vertical conduit 76 where it is combined with the cold ocean water to create a first expandite-fluid mixture that flows upward through the conduit section 76 in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination.
The first expandite-fluid mixture is directed into the separation tank 66, where it is separated into a separated expandite base which flows from the tank 66 through the conduit 77, and a separated first thermal fluid, which flows from the tank 66 and is discharged from the circuit through the conduit 73.
The separated expandite base in the conduit 77 is passed through the pump 85 to increase its pressure and then it is directed into the conduits 78 and 80. A second thermal fluid, such as warm ocean water, is introduced into the circuit through the inlet conduit 64 and is pumped by the pump 84 to be at a third combination of a pressure and temperature. The separated expandite base in conduit section 78 is injected through the nozzle system 69 into the conduit section 83 where it is combined with the warm ocean water to thermally condition (heat) the separated expandite base a second expandite-fluid mixture created by such combination the conduit 83 is directed into the gravity separation tank 67 where it is separated into the expandite mass, which flows from the tank 67 through the conduit 79, and a separated second thermal fluid, which flows from the tank 67 and is discharged from the circuit through the conduit 74.
A working fluid, such as water, is provided in the conduit 82a. The expandite mass in the conduit 79 is injected through the nozzle system 71 into the vertical conduit section 75 where it is combined with the working fluid to create an expandite working-fluid mixture that flows vertically upward through the vertical conduit 75 whereby a pressure differential is created in the conduit section 75 in relation to the remainder of the mass transport conduit for drawing the mixture upward through the conduit section 75.
The portion of the separated expandite base in the conduit 80 is inserted through the nozzle system 72 into the expandite working fluid mixture in the conduit 75 to increase the density change of the expandite-working fluid mixture.
The expandite working fluid mixture in the conduit 75 is directed into the gravity separation tank 68 where it is separated into the expandite mass, which flows from the tank 68 through the conduit 81 at the first combination of pressure and temperature, and the working fluid, which flows from the tank 68 through the conduit 82 is directed through the turbine generator 63, which converts the pressure of the flow into electricity. Following such conversion the working fluid flows through the conduit 82a at a reduced pressure.
The turbine generator 63 is positioned at an ocean depth which enables the separation tank 68 to be located where the ambient pressure outside the tank 68 is approximately the same as the pressure within the tank.
Turbine generators can be placed in the conduit sections 65, 73, 74, 75 and 76 to convert the pressure of the flow in these portions of the circuit into electricity.
Another working fluid embodiment is shown in FIG. 4. The system of FIG. 4 includes a turbine generator 87, and a mass transport conduit circuit including gravity separation tanks 88, 89 and 90, injection nozzle systems 91, 92 and 93, pump 94 and 95, vertical conduit sections 96 and 97, a warm water inlet conduit 98, a cold water inlet conduit 99, outlet conduits 100 and 101; conduit sections 102, 103, 104, 105, 106 and 107.
An expandite mass, such as low-density ethane, is provided in the conduit 106 at a first combination of pressure and temperature; and a first thermal fluid, such as cold ocean water, is introduced into the circuit through the conduit 99 at a second combination of pressure and temperature. The expandite mass in the conduit 106 is injected through the nozzle system 92 into the vertical conduit 96, where it is combined with the cold ocean water to create a first expandite-fluid mixture that flows upward through the conduit section 96 in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination.
The first expandite fluid mixture is directed into the separation tank 89, where it is separated into a separated expandite base, which flows from the tank 89 through the conduit 102, and a separated first thermal fluid, which flows from the tank 89 and is discharged from the circuit through the conduit 101.
The separated expandite base in the conduit 102 is passed through the pump 95 to increase its pressure.
A second thermal fluid, such as warm ocean water, is introduced into the circuit through the inlet 98 and is pumped by the pump 94 to be at a third combination of temperature and pressure. The separated expandite base in the conduit 102 is injected through the nozzle system 91 into the conduit section 103 where it is combined with the warm ocean water to thermally condition (heat) the separated expandite base. A second expandite-fluid mixture created by such combination in the conduit 103 is directed into the separation tank 90 where it is separated into the expandite mass which flows from the tank 90 through the conduit 104, and a separated second thermal fluid, which flows from the tank 90 and is discharged from the circuit through the conduit 100.
A working fluid, such as high density ethane is provided in the conduit 105. The expandite mass in the conduit 104 is injected through the nozzle system 93 into the vertical conduit section 97 where it is combined with the working fluid to create an expandite-working fluid mixture that flows vertically upward through the vertical conduit 97. By directing the expandite-working fluid mixture vertically through the conduit 97, a pressure differential is created in the conduit section 97 in relation to the remainder of the mass transport conduit circuit for drawing the mixture upward through the conduit section 97.
The expandite-working fluid mixture in the conduit 97 is directed into the gravity separation tank 88 where it is separated into the expandite mass, which flows from the tank 88 through the conduit 106 at the first combination of pressure and temperature, and the working fluid, which flows from the tank 88 through the conduit 107. The working fluid in the conduit 107 is directed through the turbine generator 87, which converts the pressure of the flow into electricity. Following such converstion, the working fluid flows through the conduit 105 for recombination with the expandite mass.
The turbine generator is conveniently located at or near the ocean surface. Turbine generators can be placed in the conduit sections 96, 97, 99, 100 and 101 to convert the pressure of the flow in these portions of the circuit into electricity.
The embodiment of FIG. 5 includes a turbine generator 109, and a mass transport conduit circuit including a warm water inlet conduit 110; a cold water inlet conduit 111 conduit sections 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123 and 124, gravity separation tanks 125, 126, 127 and 128; pumps 129, 130 and 131; and injection nozzle systems 132 and 133.
An expandite mass such as ethane or butane, is provided in the conduit 112 at the first combination of temperature and pressure; and a first thermal fluid, such as cold ocean water, is introduced into the circuit through the conduit 111 at a second combination of pressure and temperature. The expandite mass in the conduit 112 is injected through the nozzle system 132 into the conduit 113, where it is combined with the cold ocean water to create a first expandite fluid mixture that flows through the conduit section 113 in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination.
The first expandite-fluid mixture is directed into the separation tank 125, where it is partially separated into a separated expandite base, which flows from the tank 125 through the conduit 114, and a partially separated first expandite-fluid mixture, which flows from the tank 125 through the conduit 116 and into the separation tank 126 located at a higher elevation. The partially separated first expandite-fluid mixture is separated within the separation tank 126 into separated expandite, which flows from the tank 126 through the conduit 117, and separated first thermal fluid which flows from the tank 126 and is discharged from the circuit through the conduit 118.
The separated expandite in the conduit 117 is combined with separated expandite flowing from the conduit 122 and directed downward through the conduit 124. The pressure of the flow in the conduit 124 is increased by the pump 131. The separated expandite in the conduit 124 is combined with the separated expandite base flowing from the conduit 114 and directed downward through the conduit 115. The pressure of the flow in the conduit 115 is increased by the pump 129.
A second thermal fluid, such as warm ocean water is introduced into the circuit through the inlet conduit 110 and pumped by the pump 130 to be at a third combination of pressure and temperature. The separated expandite base in the conduit 115 is injected through the nozzle system 133 into the conduit 119, where it is combined with the warm ocean water to thermally condition (heat) the separated expandite base and to create a second expandite-fluid mixture that flows through the conduit section 119 in response to the pressure differential created by the change in average proportional density of the second expandite-fluid mixture resulting from such combination.
The second expandite-fluid mixture is directed into the separation tank 127, where it is partially separated into the expandite mass, which flows from the tank 127 through the conduit 120, and a partially separated second expandite-fluid mixture, which flows from the tank 127 through the conduit 121. The partially separated second expandite-fluid mixture is directed vertically through the conduit 121, whereby a pressure differential is created in the conduit section in relation to the remainder of the mass transport conduit circuit for drawing the mixture upward through the vertical portion of the conduit 121. The partially separated second expandite-fluid mixture is directed into the separation tank 128 where it is separated into separated expandite, which flows from the tank 128 through the conduit 122, and a separated second thermal fluid, which flows from the tank 128 and is discharged from the circuit through the conduit 123.
The expandite mass in the conduit 120 is directed through the turbine generator 109, which converts the pressure of the flow into eletricity and also reduces the pressure of the expandite mass in the conduit 112 at the first combination of pressure and temperature.
The turbine generator 109 and the separation tanks 125 and 127 are positioned at ocean depths in relation to each other for causing the pressure within the tanks 125 and 127 to be such that the tanks 125 and 127 are located at ocean depths where the respective ambient pressures outside the tanks are approximately the same as the pressures within the tanks.
Another working fluid embodiment is shown in FIG. 6. This embodiment includes turbine generator 135 and a mass transport conduit circuit including a warm water inlet conduit 136, a cold water inlet conduit 137, outlet conduits 138 and 139, conduit sections 140, 141, 142, 143, 144, 145, 146, 147, 148 and 149, gravity separation tanks 150, 151 and 152, injection nozzle systems 153, 154, 155 and 156, and a pump 157. In this system, the expandite and the working fluid are the same material, such as ethylene, although of different densities. The expandite mass consists of a mixture of the working fluid and the expandite base, which have different densities.
The expandite mass is provided in the conduit 147 as the first combination of temperature and pressure and directed into the separation tank 152, where it is separated into the expandite base, which flows from the tank 152, through the conduit 148, and the working fluid which flows from the tank 152 through the conduit 149.
A first thermal fluid, such as cold ocean water is introduced into the circuit through the conduit 137 at a second combination of pressure and temperature. The expandite base in the conduit 148 and the working fluid in the conduit 149 are injected through nozzle systems 153 and 154 respectively into the conduit 140 where they are combined with the cold ocean water to create a first expandite-fluid mixture that flows upward through the conduit section 140 in response to the pressure differential created by the change in the average proportional density of the first expandite-fluid mixture resulting from such combination.
The first expandite-fluid mixture is directed into the separation tank 150, where it is separated into a separated expandite base, which flows from the tank 150 through the conduit 141, and a separated first thermal fluid which flows from the tank 150 and is discharged from the circuit through the conduit 138. The separated expandite base in conduit 141 is separated into the conduits 142 and 143. The working fluid consists of the separated expandite base flowing through the conduit 143. If the working fluid were a different material than the expandite base, a separation tank would be required to separate the fluid flowing through the conduit 141 into the fluid flow through the conduits 142 and 143.
The pressure of the separated expandite base flowing in the conduit 142 is increased by the pump 157.
A second thermal fluid, such as warm ocean water, is introduced into the circuit through the conduit 136. The separated expandite base in the conduit 142 is injected through the nozzle system 155 into the conduit section 144, where it is combined with the warm ocean water to thermally condition (heat) the separated expandite base. A second expandite-fluid mixture created by such combination in the conduit 144 is directed into the gravity separation tank 151, where it is separated into a thermally conditioned expandite base, which flows from the tank 151 through the conduit 145, and a separated second thermal fluid, which flows from the tank 151 and is separated from the system through the conduit 139.
The working fluid in the conduit 143 is directed through the turbine generator 135, which converts the pressure of the flow to electricity and provides the working fluid at a reduced pressure in the conduit 146.
The thermally conditioned expandite base in the conduit 145 is injected through the nozzle system 156 into the conduit 147 where it is combined with the working fluid to provide the expandite mass. The expandite mass is directed upward through the vertical conduit 147 to provide the expandite mass at the first combination of pressure and temperature. By directing the expandite mass vertically through the conduit 147, a pressure differential is created in the conduit section 147 in relation to the remainder of the circuit for drawing the expandite mass upward through the conduit section 147
The embodiment of FIG. 7 includes a turbine generator 159, and a mass transport conduit circuit including a warm water inlet conduit 160; a cold water inlet conduit 161; outlet conduits 162, 163 and 167, conduits 165, 166, 168, 169, 170, 171, 172, 173, 174, 175, and 175a; injection nozzle systems 176, 177, 178 and 179; gravity separation tanks 180, 181 and 182; and pumps 183 and 184. The system further includes a conduit section 164 that is external to the mass transport conduit circuit.
An expandite mass, such as ethane, is provided in the conduit 174 at a first combination of pressure and temperature, and a first thermal fluid, such as ocean water, is provided in the conduit 175a at a second combination of pressure and temperature. The expandite mass in the conduit 174 is injected through the nozzle system 178 into the vertical conduit 165 which it is combined with the first thermal fluid to create a first expandite fluid mixture that flows upward through the conduit 165 is response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination.
By directing the first expandite-fluid mixture vertically through the conduit 165, a pressure differential is created in the conduit section 165 in relation to the remainder of the mass transport conduit circuit for drawing the mixture upward through the conduit section 165.
The first expandite-fluid mixture in the conduit 165 is directed into the separation tank 181, where it is separated into a separated expandite base, which flows from the tank 181 through the conduit 166, and a separated first thermal fluid which flows from the tank 181 and is discharged from the circuit into the external conduit 164. From the external conduit 164, the separated first thermal fluid is directed through the conduits 167 and 175. The excess first thermal fluid is discharged from the circuit through the conduit 167. The separated first thermal fluid in the conduit 175 is directed through the turbine generator 159, which converts the pressure of the flow to electricity, and provides the first thermal fluid at the second combination of pressure and temperature in the conduit 175a.
A second thermal fluid, such as cold ocean water, is introduced into the circuit through the inlet conduit 161 at a third combination of pressure and temperature. The separated expandite base in the conduit 166 is injected through the nozzle system 179 into the conduit 168 where it is combined with the cold ocean water to thermally condition (cool) the separated expandite base. A second expandite-fluid mixture created by such combination in the conduit 168 is directed into the separation tank 182, where it is separated into expandite mass, which flows from the tank 182 through the conduit 169, and a separated second thermal fluid, which flows from the tank 182 and is discharged from the circuit through the conduit 162.
The pressure of the expandite mass in the conduit 169 is increased by the pump 183 and the expandite mass is directed through conduits 170 and 171.
A third thermal fluid, such as warm ocean water, is introduced into the system through the inlet conduit 160, and has its pressure increased by the pump 184.
The portion of the expandite mass in the conduit 171 is injected through the nozzle system 176 into the conduit section 172, where it is combined with the warm ocean water from the conduit 160 to thermally condition (heat) the expandite mass. A third expandite-fluid mixture created by such combination in the conduit 172 is directed into the separation tank 180, where it is separated into a heated expandite mass, which flows from the tank 180 through the conduit 172, and a separated third thermal fluid which flows from the tank 180 and is discharged from the system through the conduit 163.
The expandite mass in the conduit 170 is injected through the nozzle system 177 into the conduit 174 where it is combined with the heated expandite mass from the conduit 173 to provide the expandite mass at the first combination of pressure and temperature in the conduit 174.
The turbine generator 159 and the separation tanks 180, 181 and 182 are positioned at ocean depths in relation to each other for causing the pressure within the tanks 180, 181 and 182 to be such that the tanks 180, 181 and 182 are located at ocean depths where the respective ambient pressures outside the tanks are approximately the same as the pressures within the tanks.
The embodiment of FIG. 8 is similar to the embodiment of FIG. 7, with only three significant variations. The portions of the FIG. 8 embodiment that are the same as the FIG. 7 embodiment are indicated by the same reference numerals in the Drawing.
One variation is that the expandite mass is provided in the conduit 170 at the first combination of pressure and temperature, and is injected through an injection nozzle system 186 into the conduit 165 where it is combined with the thermal fluid in the conduit 175a to create the expandite-fluid mixture; and the heated expandite mass in the conduit 173 is injected through an injection nozzle system 187 into the conduit 165 where it is combined with the expandite-fluid mixture.
A second variation is that the first thermal fluid that is directed to the turbine generator 159 is provided through a conduit 188 from a conduit 189, which draws the separated thermal fluid from the separation tank 180. Excess separated thermal fluid in the conduit 189 is discharged from the circuit through an outlet conduit 190.
A third variation is that the separated first thermal fluid that flows from the tank 181 is discharged from the circuit through the conduit 191.
The embodiment of FIG. 9 combines several of the features of the embodiments of FIGS. 7 and 8, with the portions thereof that are the same being indicated by like reference numerals in the Drawing. It should be noted, however, that in the embodiment of FIG. 9, the heated expandite mass in the conduit 173 is injected through the nozzle system 187 into the conduit 165 prior to the expandite mass in the conduit 170 being injected into the conduit 165 through the nozzle system 186. This means that the heated expandite mass in the conduit 173 is injected into the vertical conduit 165 and combined 175a; and the expandite mass in the conduit 170 is injected into the resulting mixture of the first thermal fluid and heated expandite mass in the conduit 165 to create the first expandite-fluid mixture therein.
Another significant variation is that the first thermal fluid that is directed to the turbine generator 159 is provided through a conduit 160b from the warm water inlet conduit 160.
Warm water introduced through the conduit 160 also is directed through the conduit 160a into the conduit 172, where it is combined with the expandite mass from the conduit 171.
The embodiment of FIG. 10 utilizes a partially separated expandite mass. This embodiment includes a turbine generator 192, and a mass transport conduit system including a warm water inlet conduit 192, a cold water inlet conduit 194, outlet conduits 195 and 196, conduits 197, 198, 199, 200, 201, 202 and 203; gravity separation tanks 205, 206 and 207; injection nozzle systems 209 and 210; and a pump 211.
An expandite mass, such as ethane, is provided in the conduit 202 at a first combination of pressure and temperature, and a first thermal fluid, such as warm ocean water, is introduced into the circuit through the conduit 193 at a second combination of pressure and temperature. The expandite mass in the conduit 202 is injected through the nozzle system 209 into the conduit 203, where it is combined with the first thermal fluid to create a first expandite-fluid mixture that flows into the separation tank 205 in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination.
The first expandite-fluid mixture is separated in the separation tank 205 into a partially separated expandite mass, which flows from the tank 205 and is directed upward through the vertical conduit 197, and a first separated first thermal fluid, which flows from the tank 205 and is discharged from the circuit through the conduit 196.
By directing the partially separated expandite mass vertically through the conduit 197, a pressure differential is created in the conduit section 197 in relation to the remainder of the mass transport circuit for drawing the partially separated expandite mass upward through the conduit section 197.
The partially separated expandite mass in the conduit 197 is directed into the separation tank 206, where it is separated into a separated expandite base, which flows from the tank 206 through the conduit 198, and a second separated first thermal fluid which flows from the tank 206 through the conduit 199. The turbine generator 192 converts the pressure of the flow of the second separated first thermal fluid in the conduit 199 into electricity. The second separated first thermal fluid flows from the turbine generator 192 and is discharged from the circuit through the conduit 200.
A second thermal fluid, such as cold ocean water, is introduced into the circuit through the inlet conduit 194 at a third combination of temperature and pressure. The separated expandite base in the conduit 198 is injected through the nozzle system 210 into the conduit 201 where it is combined with the second thermal fluid to thermally condition (cool) the separated expandite base and to create a second expandite-fluid mixture in the conduit 201.
The second expandite-fluid mixture in the conduit 201 is directed into the separation tank 207 where it is separated into the expandite mass, which flows from the tank 207 though the conduit 202, and a separated second thermal fluid, which flows from the tank 207 and is discharged from the circuit through the conduit 195. The pump 211 increases the pressure of the expandite mass in the conduit 202 to provide the expandite mass at the first combination of pressure and temperature.
The embodiments of FIGS. 11, 12 and 13 are systems wherein fewer separation steps are employed. Although such embodiments may be somewhat less efficient than the other embodiments discussed herein, they do provide savings in construction costs.
The embodiment of FIG. 11 includes a turbine generator 212, and a mass transport conduit circuit including a warm water inlet conduit 213, a cold water inlet conduit 214; an outlet conduit 216, vertical conduits 217 and 218; conduits 219 and 220; a gravity separation tank 222 and injection nozzle system 224 and 226.
An expandite mass is provided in the conduit 219 at a first combination of pressure and temperature, and a first thermal fluid, such as warm ocean water is provided in the conduit 220 at a second combination of pressure and temperature. The first thermal fluid is introduced into the circuit through the inlet conduit 213 and diverted through the turbine generator, which converts the pressure of the fluid flow into electricity. The first thermal fluid flows from the turbine generator 212 through the conduit 220 at the second combination of pressure and temperature.
The expandite mass in the conduit 219 is injected through the nozzle system 224 into the vertical conduit 217 where it is combined with the first thermal fluid to create a first expandite-fluid mixture that flows vertically upward in the conduit 217 in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination. By directing the first expandite-fluid mixture vertically through the conduit 217, a pressure differential is created in the conduit section 217 in reation to the remainder of the conduit circuit for drawing the mixture upward through the conduit section 217.
A second thermal fluid, such as cold ocean water, is introduced into the circuit through the inlet conduit 214 at a third combination of pressure and temperature, and is injected through the nozzle system 226 into the vertical section of the conduit 218 where it is combined with the first expandite-fluid mixture to thermally condition (cool) the first expandite-fluid mixture. Such combination creates a second expandite-fluid mixture in the conduit 218.
The second expandite-fluid mixture in the conduit 218 is directed into the separation tank 222, where it is separated into the expandite mass, which flows from the tank 222 through the conduit 219 at the first combination of pressure and temperature, and a separated thermal fluid, which flows from the tank 222 and separated from the system through the conduit 216.
The embodiment of FIG. 12 includes a turbine generator 228, and a mass transport conduit circuit including a warm water inlet conduit 229, a cold water inlet conduit 230, vertical conduit sections 232 and 233, conduits 235 and 236, an outlet conduit 238, a gravity separation tank 240 and injection nozzle systems 241 and 242.
An expandite mass, such as a mixture of ethane and ocean water, is provided in the conduit 236 at a first combination of pressure and temperature. A first thermal fluid, such as warm ocean water, is introduced into the circuit through the inlet conduit 229 and directed through the turbine generator 228. The turbine generator 228 converts the pressure of the flow of the first thermal fluid into electricity and reduces the pressure of the flow to provide the first thermal fluid in the conduit 235 at a second combination of pressure and temperature.
The expandite mass in the conduit 236 is injected through the nozzle system 241 into the vertical conduit 232 were it is combined with the first thermal fluid to create a first expandite-fluid mixture that flows vertically upwards in the conduit 232 in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination. By directing the first expandite-fluid mixture vertically through the conduit 232, a pressure differential is created in the conduit section 232 in relation to the remainder of the conduit circuit for drawing the mixture upward through the vertical conduit section 232.
The first expandite-fluid mixture in the conduit 232 is directed into the separation tank 240, where it is separated into a separated expandite base, which flows from the tank 240 through the vertical conduit section 233, and a separated thermal fluid which flows from the tank 240 and is discharged from the circuit through the conduit 238. By directing the separated expandite base vertically through the conduit section 233, a pressure differential is created in relaton to the remainder of the conduit circuit for drawing the separated expandite base downward through the conduit section 233.
A second thermal fluid, such as cold ocean water, is introduced into the circuit through the inlet conduit 230 and is injection through the nozzle system 242 into the conduit 236, where it is combined with the separated expandite base (ethane) to thermally condition (cool) the ethane and create the expandite mass consisting of the mixture of ethane and ocean water at the first combination of pressure and temperature.
The embodiment of FIG. 13 includes a turbine generator 244 and a mass transport conduit circuit including a warm water inlet conduit 245; a cold water inlet conduit 246; an outlet conduit 247; conduit sections 248, 250, 251 and 252; a gravity separation tank 254 and injection nozzle systems 255 and 256.
An expandite mass, such as ethane, is provided in the conduit 250 at a first combination of pressure and temperature; and a first thermal fluid, such as cold ocean water, is introduced into the circuit through the inlet conduit 246 at a first combination of pressure and temperature. The first thermal fluid in the conduit 246 is injected through the nozzle system 255 into the conduit 251 where it is combined with the expandite mass from the conduit 250 to create a first expandite-fluid mixture that flows through the conduit 251 in the direction indicated by the arrows therein in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination.
A second thermal fluid, such as warm ocean water, is introduced into the circuit through the inlet conduit 245 at a third combination of pressure and temperature. The first expandite-fluid mixture in the conduit 251 is injected through the nozzle system 256 into the vertical conduit section 248, where it is combined with the second thermal fluid to thermally condition (heat) the first expandite-fluid mixture. Such combination creates a second expandite-fluid mixture in the conduit 248 that is directed vertically therein to create a pressure differential in the vertical conduit 248 in relation to the remainder of the circuit for drawing the second mixture upward through the conduit 248.
The second expandite-fluid mixture is directed into the separation tank 254, where it is separated into the expandite mass, which flows from the tank 254 through the conduit 252, and a separated thermal fluid, which flows from the tank 254 and is discharged from the system through the conduit 247.
The separated expandite base in the conduit 252 is directed through the turbine generator 244, which converts the pressure of the flow into electricity and provides the expandite mass in the vertical conduit 250 at the first combination of pressure and temperature. The separated expandite base is directed vertically through the conduit 250, and thereby creates a pressure differential therein in relation to the remainder of the circuit for drawing the separated expandite base vertically upward through the conduit 250.
The embodiment of FIG. 14 includes two turbine generators 258 and 259, and a mass transport conduit circuit including a warm water inlet conduit 260; a cold water inlet conduit 261; vertical conduits 262 and 263; conduits 264, 265, 266 and 267; outlet conduits 268 and 269; gravity separation tanks 270 and 271 and injection nozzle systems 272 and 273.
An expandite mass, such as nitrobenzene, is provided in the conduit 262 at a first combination of pressure and temperature, and a first thermal fluid, such as warm ocean water is introduced into the circuit through the circuit 260 at a second combination of pressure and temperature. The first expandite mass is injected through the nozzle system 272 into the conduit 264, where it is combined with the first thermal fluid to create a first expandite-fluid mixture that flows downward through the conduit 264 in response to the pressure differential created by the change in average proportional density of the first expandite-fluid mixture resulting from such combination.
The first expandite-fluid mixture is directed into the separation tank 270, where it is separated into a separated expandite base, which flows from the tank 270 through the conduit 265, and a separated first thermal fluid, which flows from the tank 270 and is discharged from the system through the conduit 268.
The separated expandite base in the conduit 265 is directed through the turbine generator 258, which converts the pressure of the flow into electricity and provides the separated expandite base in the vertical conduit 263 at a reduced pressure. The separated expandite base is directed vertically through the conduit 263, and thereby creates a pressure differential therein in relation to the remainder if the circuit for drawing the separated expandite base vertically downward through the conduit 263.
A second thermal fluid, such as cold ocean water, is introduced into the circuit through the conduit 261 at a third combination of pressure and temperature. The separated expandite base in the conduit 263 is injected through the nozzle system into the conduit 266 where it is combined with the cold ocean water to thermally condition (cool) the separated expandite base, and to create a second expandite-fluid mixture that flows upward through the conduit 267 in response to the pressure differential created by the change in average proportional density of the second expandite-fluid mixture resulting from such combination.
The second expandite-fluid mixture in the conduit 266 is directed into the separation tank 271, where it is separated into the expandite mass, which flows from the tank 271 through the conduit 267, and a separated second thermal fluid, which flows from the tank 271 and is discharged from the circuit through the conduit 269.
The separated expandite mass in the conduit 267 is directed through the turbine generator 259, which converts the pressure of the flow into electricity and provides the expandite mass in the vertical conduit 262 at the first combination of pressure and temperature. The expandite mass is directed vertically through the conduit 262, and thereby creates a pressure differential therein in relation to the remainder of the circuit for drawing the expandite mass vertically upward through the conduit 262.
Each of the gravity separation tanks included in the various systems described hereinabove for separating an expandite-fluid mixture preferably includes a nucleation system (not shown) for creating films, bubbles and/or sprays of the expandite mixture to create more surface area of the expandite-fluid mixture for enabling the expandite to become free of the thermal fluid and to separate more readily from the mixture. Nucleation may be enhanced by shock waves or sonar vibrations.
Even after all of the series of separation steps have been completed some of the expandite mass typically remains dissolved in the separated thermal fluid that is discharged from the mass transport conduit circuit. It is important that the expandite mass material be non-polluting to the environment in which it is discharged. Also it should be inexpensive since it will have to be replenished within the circuit. However, these factors are of less concern in a system wherein the warm and cold thermal fluids are provided from reservoirs external to the circuit that are of a limited size, such as a lagoon or a solar collector. This is because the expandite mass that is dissolved in a thermal fluid will eventually constitute a certain percentage of the fluid in the reservoir and thereby remain in the system. | A system and method of thermal energy conversion is disclosed. The method includes the steps of (a) providing a mass of unencased fluid expandite in a mass transport conduit circuit at a first combination of temperature and pressure; (b) introducing a thermal fluid into the mass transport conduit circuit from a source external to the mass transport conduit circuit at a second combination of temperature and pressure; (c) combining the provided expandite mass with the introduced thermal fluid in a given conduit of the circuit to create an expandite-fluid mixture having a density at some place in the given conduit that is changed from the average proportional density of the expandite mass and the thermal fluid at their respective prevailing combinations of temperature and pressure prior to such combination with each other to create a pressure differential that enhances the flow of the fluids contained within the circuit; (d) directing at least a portion of the fluids contained within the circuit to flow vertically through a given portion of the conduit circuit to create a pressure differential in the given portion of the circuit in relation to the remainder of the conduit circuit to thereby enhance the flow of the fluids contained with the conduit circuit, and (e) converting the pressure of at least a part of the enhanced flow of the contained fluids through the conduit circuit into a useful form of energy. Step (a) includes the steps of: (f) separating from the expandite-fluid mixture, an expandite base which comprises at least a portion of the expandite mass; and (f') thermally conditioning the expandite base. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of ornamental landscaping and, in particular, to a filter system designed to efficiently remove solid wastes and biologically decompose suspended wastes in fish ponds.
2. Description of the Related Art
Fish ponds accumulate and generate a variety of contaminants and waste products that must be removed and treated to maintain the attractive appearance of the fish pond and the health of the fish living therein. The exposed water surface tends to retain air blown dust, dirt, and leaves and other plant matter that falls in. The fish themselves produce excrement that is a solid waste material and a source of unwanted biological activity. The temperate closed water ecosystem that is essential for the fish is also an excellent environment for the growth of algae and other undesirable living organisms. Fish food that remains uneaten by the fish can contaminate the pond and nourish undesirable living organisms. The closed system of a fish pond also favors chemical processes such as ammonia production that, if left unchecked, can rapidly degrade the appearance of the fish pond and its ability to support healthy fish.
The accepted method of maintaining the health and appearance of a fish pond is to separate the solid waste from the water, react the chemicals to either remove them or make them non-damaging, and treat the water to kill undesirable organisms. Two methods have typically been used to do this. One is to filter out the solid wastes and dispose of them, treat the water with a variety of chemicals and/or high intensity UV light to kill biological undesirables, and react the undesirable chemicals. The other is to employ a filter medium that retains the solid waste and decomposes the waste with biologically active bacteria that live on the filter medium. This method would also typically require treatment with high intensity UV light or chemicals to eliminate the undesirable biological and chemical constituents, although the chemical and/or UV light treatment regimen may not be as rigorous as with simple filtering.
A variety of methods and apparatuses are known to remove solid material from a liquid, however a major concern with removal of solid waste is what to do with the waste once it is separated from the water. Separation devices that depend on density differences, such as a centrifuge, are not effective in fish pond applications because many of the waste solids are approximately the same density as the water they are in, therefore the effective devices typically employ some type of filtering to trap the solids. The two major ways to handle the separated waste are to discard the waste trapped in a filter along with the filter or to backwash the filter and direct the waste stream elsewhere. A disadvantage of removing the waste trapped in a filter along with the filter is that generally these types of filters are a single use filter and thus must be replaced with a new one when the old one is full. It can be appreciated that the labor and cost to perform this replacement would be a drawback to a user for which the fish pond is a decorative and recreational item.
In order to avoid the cost and inconvenience of changing filter elements, the preferred method of removing trapped waste is to utilize some form of backwashing. Backwashing essentially consists of reversing the direction of water flow in the filter and thereby forcing the waste products out a waste outlet. The filter media does not typically need to be removed and after the backwashing is complete, the filter media is ready to retain more waste. Advantageously, fish ponds are often located adjacent garden areas and the backwashed water contains partially decomposed fish and vegetable waste that makes a beneficial fertilizer in the garden. However, the water discharged in the backwashing procedure is typically a cost to the user and minimizing water discharge is a concern particularly in areas where water is in limited supply.
The biological reaction process is an advantageous adjunct because the heterotrophic bacteria that perform the reaction are naturally occurring in the pond water. No user action is needed to establish and maintain a colony of beneficial bacteria other than to provide a place for them to live. Also, biological reaction converts many of the undesirable chemicals to non-harmful forms and thus reduces the need for chemical treatment. The chemicals used for chemical treatment are relatively expensive and many users would understandably like to minimize their handling of chemicals. The heterotrophic bacteria are not suited to live freely suspended in water and require a surface on which to grow. This has typically been done on the filter medium which generally consists of a gravel bed or filter mat.
A disadvantage to biological reaction is the relatively large amount of reactor volume and time typically required for the process to occur. With traditional gravel or filter mats, a biological filter/reactor can require a filter/reactor volume of up to 40% of the volume of the pond itself. It can be appreciated that such a large filter/reactor assembly is expensive to purchase and install and can negatively affect the aesthetics of the fish pond system. In addition a traditional biological reaction filter design can require several weeks to several months for the bacteria to substantially decompose the deposited wastes. The time required for waste decomposition must be such that the waste is decomposed at at least the rate it is deposited. Otherwise the filter becomes overloaded and can no longer protect the health and appearance of the pond.
As the bacteria live on a solid surface, there is an upper limit to how many can live on a given area, i.e. their population density. The time and volume required for a biological reaction filter can be dramatically reduced by providing increased area for the bacteria to live on and thereby increasing the number of bacteria resident in the filter reactor. The optimal filter media provides the highest surface area-to-volume ratio possible. With gravel or fibrous mats, the bacteria live on the surface and from a consideration of the shape of a piece of gravel or fiber it can be seen that other configurations of filter media would provide greater surface area for a given volume of media.
One type of filter media on the market with a higher surface area to volume ratio than gravel or fibers is the ACE-1400 media. The ACE-1400 media is made of plastic tubing with a specific gravity slightly less than one, which is cut to be slightly longer than the diameter of the tubing. The ACE-1400 is approximately 3.5 mm in diameter and 5 mm long. It can be appreciated that a hollow tube can support bacteria on both the outer and the inner surface. The size and shape of the hollow tube media is such that it has 15 to 20 times the surface area of an equivalent volume of gravel or fiber matting.
The ACE-1400 type media is typically placed in a container and pond water is pumped through the container so as to flow generally upwards. Since the ACE-1400 media has a specific gravity slightly less than one, the media floats towards the top of the container. Since the pond water is generally flowing upwards in the container, waterborne waste material is trapped throughout the media, but predominantly towards the bottom. The naturally occurring bacteria reside on and within the ACE-1400 media and digest the waste that lodges within the media.
The container is also provided with valves and piping to backwash the container periodically by reversing the water flow direction downwards and then out of the container. The backwashing causes the media to swirl and tumble, thereby releasing trapped solids. A properly sized container filled with the appropriate amount of media would generally require backwashing once a week. The container is provided with screens so that the media does not escape the container during either backwashing or normal operation. The filter system is also provided with screens to restrict larger solids such as leaves, twigs, and fish from being pumped into the filter container.
It can be appreciated that the more media that is in a filter system, the more surface area is provided for heterotrophic bacteria growth. However, because the ACE-1400 filter media is of a uniform size and shape, movement of the water tends to cause the filter elements to stack in a uniform manner, particularly when the container is filled to a relatively high percentage of capacity. The stacking process tends to create channels or voids in the filter media. These channels provide paths for the water to flow along without requiring that the water pass through the filter media. It can be appreciated that the filter is not effective in trapping and decomposing wastes if the water is not passing through the media. The stirring motion of backwashing randomizes the orientation of the filter elements, however they tend to re-stack and create channels in a relatively short time after the system returns to normal filtering flow.
While the ACE-1400 filter media and system offer advantages over traditional disposable filters and chemical treatment or gravel or fiber matting filter systems employing biological waste decomposition, it can be appreciated that improvements upon this system would be an advantage to the users of fish ponds. It can be appreciated that there is an ongoing need for a filter system for fish ponds that employs naturally occurring bacterial metabolization of wastes to remove these wastes from fish ponds. The system should be economical to purchase and install. The filter media should be reusable and provide the maximum surface area to volume ratio possible to support a maximum number of beneficial bacteria and to enable the system to be sized as small as possible and decompose the solid wastes as rapidly as possible. The system should require minimal use of chemicals to treat the water. The backwashing method should be as efficient as possible to remove the maximum amount of waste and extend the periods between backwashes, while avoiding channeling effects and corresponding failure to filter.
SUMMARY OF THE INVENTION
The aforementioned needs are satisfied by the fish pond filter system of the present invention, which in one aspect is a novel filter media with an increased surface area-to-volume ratio. In another aspect, the invention is a filter reactor with a more efficient backwashing system.
The extruded bio-tube filter media of the present invention is formed from extruded ABS plastic with a specific gravity slightly greater than one. The extruded bio-tube is generally tubular with internal and external ribbing. The addition of the internal and external ribbing provides approximately twice the surface area for the bio-tube of the present invention compared to a similar sized simple tube media, such as the ACE-1400. In addition, the internal ribbing provides smaller interior passages and allows the media to trap proportionally smaller waste material.
An additional advantageous feature of the present invention is that the media is provided in several different sizes. Also, the present invention is sized so as to be generally 1.3 times as long as it is in diameter. The differing sizes and the shape of the media of the present invention inhibit uniform stacking of the media material. Since the media cannot readily stack together in a uniform fashion, channeling of the material is also inhibited.
In another aspect of the invention, an efficient backwashing system is provided. The system includes jets adapted to create a vortex within the filter media container during the backwashing operation. The vortex created more efficiently dislodges accumulated waste material and directs the dislodged waste and carrier water out a waste pipe. The vortex created within the fish pond filter system of the present invention more completely cleans the filter media in a shorter time and requires less water to do so. Thus, the fish pond filter system saves time and money. These and other objects and advantages of the present invention will become more fully apparent from the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an end view of a typical bio-tube of the present invention;
FIG. 2 is a side view of a typical bio-tube of the present invention;
FIG. 3 shows end and side views of three different sizes of bio-tubes of the present invention and their relative sizes;
FIG. 4 is an assembled, perspective view of the internal plumbing of a fish pond filter container assembly;
FIG. 5 is a close-up perspective view of the backwash jets and intake pipe assemblies of a fish pond filter system;
FIG. 6 is an exploded, cutaway, perspective view of the filter mode of the fish pond filter system;
FIG. 7 is an exploded, cutaway, perspective view of the backwash mode of the fish pond filter system;
FIG. 8 is a top view of a valve body and valve handle of the present invention showing the positions of the different operational modes of the valve body and filter system;
FIG. 9 is a side view of the assembled fish pond filter system; and
FIG. 10 shows a typical installation of the fish pond filter system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made to the drawings, wherein like numerals refer to like parts throughout. A fish pond filter system 100 draws water from a fish pond 300 , filters and treats the water to remove waste 304 , and returns the water to the fish pond 300 as shown in FIG. 10 . The fish pond 300 of this embodiment is an open air, closed-system container of water. The fish pond 300 can be outside or placed within a building or other enclosed structure. The fish pond 300 includes a plurality of fish 302 . Fish 302 shall herein be understood to include fish, crawdads, mud puppies, frogs, turtles, shrimps, or any other vertebrate or invertebrate animals suited to live at least partially in an aquatic environment. The fish 302 generate waste 304 , which is at least in part at least semi-solid biological waste material. Waste 304 shall be herein understood to also include other material that finds its way into the fish pond 300 such as leaves, other vegetable matter, dirt, or insects. The fish pond filter system 100 also includes naturally occurring heterotrophic bacteria 310 . The heterotrophic bacteria 310 feed on the waste 304 typically found in a fish pond 300 and remove the waste 304 from the fish pond 300 in a manner that will be described in greater detail below. The fish pond filter system 100 comprises a pre-filter 306 as shown in FIG. 10 which is positioned and adapted to screen out larger waste 304 particles which are approximately larger than ⅛″ in a well known manner.
The fish pond filter system 100 comprises bio-tube 102 filter media as shown in FIGS. 1 and 2. The bio-tubes 102 provide a surface to support the growth of heterotrophic bacteria 310 in a manner which is well known in the art and will be better appreciated following a more detailed description of the structure of the bio-tubes 102 and the fish pond filter system 100 . The bio-tubes 102 also retain and subsequently release water-borne solid waste 304 materials which the fish pond filter system 100 passes over the bio-tubes 102 in a manner that will be described in greater detail below. The bio-tubes 102 , of this embodiment, are extruded from ABS plastic in a well known manner. The bio-tubes 102 are provided with a plurality of integral structures formed at the same time and which will be described in greater detail below. The bio-tubes 102 of this embodiment have a finished specific gravity slightly greater than one so as to be slightly non-buoyant in water.
The bio-tubes 102 structure comprises a ring wall 104 . The ring wall 104 , of this embodiment, is made of ABS plastic and is generally an elongate, hollow, openended cylinder approximately 0.300″ outside diameter, 0.250″ inner diameter, and 0.390″ in length. The ring wall 104 has a wall thickness of approximately 0.025″ and provides a growth surface for bacteria in a manner that will be described in greater detail below. The ring wall 104 has an inner surface 106 and an outer surface 110 coaxial with and opposite the inner surface 106 .
The structure of the bio-tubes 102 further comprises external ribs 112 . The external ribs 112 are made of the same ABS plastic material as the bio-tubes 102 and are generally elongate rectangles of approximately 0.018″×0.035″×0.390″. The external ribs 112 are extruded with the bio-tubes 102 such that a first side of the external ribs 112 is adjacent and materially continuous with the outer surface 110 of the ring wall 104 . The external ribs 112 are positioned such that the long axis of the external ribs 112 (0.390″) is coaxial with the long axis of the bio-tube 102 . In this embodiment, 18 external ribs 112 extend radially. outward from the outer surface 110 of the ring wall 104 and are approximately equally spaced about the circumference of the ring wall 104 which in this embodiment is approximately every 20° of angle. The external ribs 112 provide additional surface area to support the growth of heterotrophic bacteria 310 .
The structure of the bio-tubes 102 also comprises divider walls 114 . In this embodiment, the divider walls 114 are three elongate rectangles approximately 0.018″×0.125″×0.390″ and are made from the same ABS plastic as the bio-tubes 104 . The divider walls 114 have a first edge 116 along a long edge (0.390″) and a second edge 120 opposite the first edge 116 . The divider walls 114 are positioned such that the first edges 116 of the divider walls 114 are adjacent and materially continuous with the inner surface 106 of the ring wall 104 and the second edge 120 of each divider wall 114 is adjacent and materially continuous with the second edge 120 of each of the other divider walls 114 . The divider walls 114 are further positioned so as to be approximately equally spaced radially outwards from the common second edges 120 , which in this embodiment is 120° of angle. The divider 114 walls also support growth of heterotrophic bacteria 310 .
It should be appreciated that the ring wall 104 , externals ribs 112 , and divider walls 114 are all structures of the bio-tube 102 and, in the preferred embodiment, are extruded at the same time and from the same ABS material. The bio-tube 102 with the structures described has a surface area available for bacterial 310 growth that is approximately twice the surface area of a simple hollow, open-ended cylinder of similar dimensions, but without the external ribs 112 and the divider walls 114 . It should be appreciated that the overall shape of the bio-tube 102 and the number, shape, and placement of the external ribs 112 and divider walls 114 can be varied by one skilled in the art from the configurations described in this preferred embodiment without detracting from the spirit of the disclosed invention.
The bio-tubes 102 also comprise a plurality of internal passages 122 . The internal passages 122 are the openings within the bio-tubes 102 defined by two adjacent divider walls 114 and the included arc of the inner surface 106 of the ring wall 104 . The inner passages 122 provide a restricted opening for the passage of water and block and hold solid waste 304 material that is larger than the dimensions of the inner passage 122 . In this embodiment, the inner passages 122 will block solid objects that are generally larger than 0.100″ in at least two orthogonal dimensions. The bio-tubes 102 with internal passages 122 block solid objects that are approximately one-third as large as simple hollow cylinders of comparable size.
FIG. 3 shows one embodiment of the present invention with three different sizes of bio-tubes 102 . The bio-tubes 102 as shown are generally cylinders and in this embodiment are approximately 0.180″ diameter by 0.234″ long, 0.240″ in diameter by 0.312″ long, and 0.300″ in diameter by 0.390″ long. The different sizes of bio-tubes 102 inhibits uniform stacking of the bio-tubes 102 during use in a manner which will be described in greater detail below. It should be appreciated that alternative shapes, sizes, and number of different sizes and/or shapes of bio-tubes 102 could be employed without detracting from the spirit of the present invention.
The fish pond filter system 100 also comprises a water flow controller 124 as shown in FIG. 4 . The water flow controller 124 comprises a valve body 130 . The valve body 130 is provided with internal structures to control water flow in a manner well understood by those skilled in the art. The water flow controller 124 also comprises a valve handle 126 , which is an elongate member, approximately 8″ in major dimension and made of a plastic material. A first end 128 of the valve handle 126 is rotatably affixed to a top end 154 of the valve body 130 such that rotation of the valve handle 126 induces the valve body 130 to freely permit or restrict water flow through an inlet pipe 132 , an outlet pipe 134 , a waste pipe 136 , and/or a stand pipe 146 all exiting from the valve body 130 in response to the positioning of the valve handle 126 .
The inlet pipe 132 , outlet pipe 134 , waste pipe 136 , and stand pipe 146 of this embodiment are elongate members, generally open cylinders in profile, and made of a PVC plastic material. The inlet pipe 132 receives untreated water from the fish pond 300 . The outlet pipe 134 directs water which has been treated and filtered by the fish pond filter system 100 in a manner which will be described in greater detail below back to the fish pond 300 . The waste pipe 136 directs water, which may contain waste material 304 , out of the fish pond filter system 100 . The stand pipe 146 directs water flow to and from a backwash jet assembly 170 and intake tube assembly 172 in a manner which will be described in greater detail below.
The water flow controller 124 also comprises a pressure gauge/sight glass 140 . A first end 141 of the pressure gauge/sight glass 140 is provided with standard ¼″ NPT and is therewith threaded into the valve body 130 in a well known manner. The pressure gauge/sight glass 140 is adapted to provide a visual indication of the water pressure within the valve body 130 in a well known manner. The pressure gauge/sight glass 140 is also adapted to provide a visual indication of the presence of water within the valve body 130 . The water pressure indicated by and the visual condition of the water seen in the pressure gauge/sight glass 140 serve as indicia for an operator to control the operation of the fish pond filter system 100 in a manner which will be described in greater detail below.
The water flow controller 124 also comprises an attachment flange 142 . The attachment flange 142 is generally circular and approximately 7″ in diameter. The attachment flange 142 is made of a plastic material and is adapted to attach the water flow controller 124 to a container 202 , as shown in FIG. 9, in a manner that will be described in greater detail below.
The water flow controller 124 also comprises a media screen 144 . The media screen 144 is generally a cylinder, open on a first end 150 , closed on a second end 152 and approximately 6″ in diameter and 4″ high. The media screen 144 is made of a plastic material and is provided with a plurality of openings 148 . The openings 148 are generally rectangular, through-going holes in the media screen 144 sized so as to block passage of the bio-tubes 102 through the media screen 144 yet to readily allow the passage of liquid water. The media screen 144 has a second end 152 opposite the first end 150 . A circular opening 160 is provided in the center of the second end 152 of the filter screen 144 . The opening 160 is sized to fit closely around the outer diameter of the stand pipe 146 , which, in this embodiment, is approximately 1½″ in diameter.
The first end 150 of the media screen 144 is placed adjacent a bottom end 156 of the valve body 130 opposite the top end 154 . The media screen 144 is positioned such that the opening 160 is aligned with the center of the bottom end 156 of the valve body 130 . The media screen 144 is attached to the bottom end 156 of the valve body 130 with a plurality of screws in a well known manner. A first end 164 of the stand pipe 146 is positioned through the opening 160 in the media screen 144 and further into contact with the valve body 130 so as to securely attach to the valve body 130 and the media screen 144 in a friction fit in a well known manner.
A second end 166 of the stand pipe 146 is connected to the backwash jet assembly 170 and the intake tube assembly 172 as shown in FIG. 4 and in a close-up view in FIG. 5 . The backwash jet assembly 170 of this embodiment comprises a manifold 174 . The manifold 174 is made of a PVC plastic material and is adapted to contain and direct water flow in a manner which will be described in greater detail below. The manifold 174 includes 12 ports 176 . The ports 176 are adapted to direct water flow and are part of and made of the same material as the manifold 174 . The ports 176 are generally circular structures of the manifold 174 which extend radially outward and are arranged in three levels 184 a-c . Each level 184 a-c comprises four ports 176 positioned so as to be at the same distance along the major axis of the manifold 174 and to be approximately equally spaced about the circumference of the manifold 174 which is approximately a spacing of 90° of angle apart.
A top end 180 of the manifold 174 is provided with female threads in a well known manner. The second end 166 of the stand pipe 146 is provided with male threads in a well known manner such that the male threads of the stand pipe 146 mate with the female threads of the manifold 174 . The top end 180 of the manifold 174 and the second end 166 of the stand pipe 146 are threaded together to achieve the connection between the stand pipe 146 and the backwash jet assembly 170 and the intake pipe assembly 172 . In an alternative embodiment, the threading referred to above need not be present and the manifold 174 and the second end 166 of the stand pipe 146 are joined with a cementing process well known to those skilled in the art.
A first level 184 a comprising four ports 176 is located approximately 1″ from the top end 180 of the manifold. A t-fitting 186 is connected to each port 176 by a cementing process well known in the art. The t-fittings 186 are plastic pipe structures adapted to direct the flow of water in two substantially orthogonal directions. The t-fittings 186 have three openings 188 for the passage of water. A first opening 188 of each t-fitting 186 is attached to a port 176 of the first level 184 of the manifold 174 with a known cementing process. A second opening 188 of each t-fitting 186 opposite the first opening 188 is connected to a first opening 188 of an elbow 190 with a known cementing process.
The elbows 190 are plastic pipe structures which are bent at approximately a 90° angle such that water that enters one opening 188 of the elbow exits a second opening 188 in a direction generally 90° from the direction it entered. Jet caps 192 are connected to the second opening 188 of each elbow 190 and to the third opening 188 of each t-fitting 186 using a known cementing process. The jet caps 192 are generally cylindrical, open on one end, and closed on the other end. The jet caps 192 are made of a PVC plastic material and are sized to conform closely to the openings 188 of the t-fittings 186 and the elbows 190 . The jet caps 192 are provided with a jet opening 194 in the closed end. The jet opening 194 is a through-going hole in the jet cap 192 . The jet opening 194 is sized to permit restricted flow of water such that water delivered under pressure to the inside of the jet caps 194 exits at a high velocity through the jet opening 194 .
The t-fittings 186 and elbows 190 are connected to each other and the manifold 174 such that the jet caps 192 fitted to the t-fittings 186 and the elbows 190 point generally tangentially in a clockwise or counterclockwise direction in the plane of the first level 184 . The t-fittings 186 and elbows 190 are further positioned such that the t-fittings 186 and elbows 190 point at an elevation or declination from the plane of the level 184 a so as to have an elevation or declination of generally between 0° and ±45° from the plane of the level 184 a and thereby the plane of the tangential clockwise or counterclockwise direction. Thus water that is supplied to the t-fittings 186 and elbows 190 is directed out of the jet openings 194 so as to spray out in a generally tangential manner but also in a slightly elevated or declined direction. This serves to create a vortical flow pattern for the backwashing in a manner that will be described in greater detail below.
The intake tube assembly 172 comprises a second 184 b and third level 184 c located approximately 3″ and 5″ from the top end 180 of the manifold 174 respectively. Each of the second and third levels 184 comprises four ports 176 as previously described with respect to the backwash jet assembly 170 . A first end of an intake tube 196 is attached to each of the ports 176 of the second and third levels 184 of the manifold 174 such that the intake tube assembly 172 comprises eight intake tubes 196 . The intake tubes 196 are generally hollow, cylindrical, elongate members, open on the first end, closed on a second end, and made of a plastic material. The intake tubes 196 are provided with a plurality of intake openings 198 positioned between the first and second ends. The intake openings 198 of this embodiment are through-going slits in the wall of the intake tubes 196 and are sized and positioned to inhibit the passage of the bio-tubes 102 yet to allow minimally impeded passage of liquid water.
The ports 176 of the second and third levels 184 b and 184 c are positioned such that the intake tubes 196 extend radially outward from the manifold 174 . The ports 176 are further positioned such that the intake tubes 196 of each of the second and third levels 184 are positioned approximately 90° apart about the circumference of the manifold 174 and such that the ports 176 of the second and third levels 184 are positioned approximately 45° from being in alignment with each other. Thus, the intake tubes 196 extend radially outward approximately every 45° about the circumference of the manifold 174 in two levels 184 .
The fish pond filter system 100 comprises a filter mode 200 as shown in FIG. 6 . It should understood that FIG. 6 is an exploded, cutaway perspective view of the fish pond filter system 100 with several components of the fish pond filter system 100 not shown for clarity. FIG. 6 shows an alternative embodiment of the intake tube assembly 172 wherein the intake tubes 196 are positioned so as to extend radially outward from the manifold 174 and so as to be positioned approximately every 45° about the circumference of the manifold 174 in a single level 184 . It should be appreciated by one skilled in the art that the operation of the intake tube assembly 172 as described as follows is substantially similar to the operation of the embodiment of the intake tube assembly 172 previously described.
The fish pond filter system 100 comprises a container 202 . The container 202 is a hollow, closed structure made of a plastic material. The container 202 is sized and adapted to hold approximately 15 to 150 liters of water. The container 202 is preferably sized to adequately filter the volume of the fish pond 300 in a manner well known to those skilled in the art. The container 202 comprises an opening 204 in a top end 206 . The opening 204 is a generally circular through-going hole in the top end 206 of the container 202 and is approximately 6″ in diameter.
The water flow controller 124 is partially inserted into the container 202 through the opening 204 such that the stand pipe 146 , the backwash assembly 170 , and the intake tube assembly 172 pass into the interior of the container 202 . An O-ring 210 is placed between the top end 206 of the container 202 and the valve body 130 . The O-ring 210 is generally a toroid approximately 6″ in overall diameter and ¼″ in cross-section and is made of a rubber material. The O-ring 210 inhibits water flow out of the container 202 . The attachment flange 142 is removably attached to the container 202 so as to secure the water flow controller 124 to the container 202 and also so as to hold the O-ring 210 between the container 202 and the water flow controller 124 in compression. The attachment of the attachment flange 142 in this embodiment comprises a clamping procedure well known in the art. In an alternative embodiment, the attachment of the attachment flange 142 comprises a threading procedure or other known methods of removably attaching two assemblies.
The container 202 also comprises a bottom end 220 opposite the top end 206 . The container 202 also comprises a drain hole 216 adjacent the bottom end 220 . The drain hole 216 is a through-going hole in the container 202 and is provided with internal, female threads. The container also comprises a drain plug 212 and gasket 214 . The drain plug 212 is a brass assembly provided with external, male threads and is sized and threaded so as to be removably threaded into the drain hole 216 so as to hold the gasket 214 between the container 202 and the drain plug 212 in a known manner. The drain plug 212 and gasket 214 inhibit water flow out of the container 202 when they are inserted into the container 202 . Removal of the drain plug 212 and gasket 214 allow water contained within the container 202 to freely flow out of the container 202 .
A plurality of bio-tubes 102 as previously described are inserted into the container 202 prior to the attachment of the water flow controller 124 previously described so as to fill the container 202 to approximately 50% of capacity. The filtering mode 200 comprises positioning the valve handle 126 to the filter mode 200 position such that water flows freely into the inlet pipe 132 and exits the bottom end 156 of the valve body 130 through the media screen 144 . The water fills the container 202 and exits the container 202 by passing into the intake tube assembly 172 , through the stand pipe 146 , through the valve body 130 , and out the outlet pipe 134 .
The water entering the fish pond filter system 100 typically is drawn from the fish pond 300 and includes waste 304 . The water enters at the top end 206 of the container 202 and exits adjacent the bottom end 220 . Thus, the water flow is generally downwards. The bio-tubes 102 have a specific gravity slightly greater than unity and thus will tend to sink and rest adjacent the bottom end 220 of the container 202 in the general manner shown in FIG. 6 thereby defining the filtering media for the system 100 . Thus waste 304 contained within the water will pass generally downwards and because of the configuration of the bio-tubes 102 as previously described, the waste 304 will be substantially trapped within and on the upper extent of the bio-tubes 102 . The differing shapes and sizes of the bio-tubes 102 are such that the flow of water within the container 202 and through the bio-tubes 102 induces the bio-tubes 102 to stack in a random manner and to not create channels or voids with the bio-tubes 102 .
The waste 304 trapped within and on the bio-tubes 102 serves as food material for heterotrophic bacteria 310 . The heterotrophic bacteria 310 are naturally occurring in the fish pond 300 and are carried into the fish pond filter system 100 during use. Over time, the heterotrophic bacteria 310 establish colonies on the surface of and within the bio-tubes 102 . The heterotrophic bacteria 310 metabolize the waste 304 that becomes trapped on and within the bio-tubes 102 and substantially transform the waste 304 into forms which are more aesthetically pleasing in the fish pond 300 and which are not harmful to the health of the fish 302 in a well known manner. For example, the heterotrophic bacteria 310 metabolize nitrogenous compounds such as ammonia. The structures of the bio-tubes 102 as previously described provide a greater surface area for the culturing of the heterotrophic bacteria 310 than other known filtering systems and can support a greater density of heterotrophic bacteria 310 . Thus, the fish pond filter system 100 can process a greater waste 304 load and/or at a faster rate than other comparably sized filtering systems.
The heterotrophic bacteria 310 are not capable of completely metabolizing all of the waste 304 that typically enters a fish pond 300 and this unreacted waste 304 will accumulate over time. Eventually the amount of unreacted waste 304 will accumulate to the point of restricting flow through the fish pond filter system 100 . This situation is indicated by the water pressure indicated by the pressure gauge/sight glass 140 .
The fish pond filter system 100 comprises a backwash mode 230 as shown in FIG. 7 . The backwash 230 mode is initiated by positioning the valve handle 126 to the backwash 230 mode position. This induces the valve body 130 to direct water flow from the inlet pipe 132 , through the valve body 130 , through the stand pipe 146 , and out through the intake tube assembly 172 and the backwash jet assembly 170 and into the container 202 . The water fills the container 202 if it is not already full and then flows past the media screen 144 , into the valve body 130 , and out the waste pipe 136 .
The water flow out of the intake tube assembly 172 dislodges waste 304 material that has accumulated on the intake tubes 196 . The water flow out of and the orientation of the backwash jet openings 194 induces a vortical or cyclonic flow 232 pattern within the container 202 . This vortical flow 232 causes the bio-tubes 102 to tumble and swirl, efficiently dislodging waste 304 trapped within or on the bio-tubes 102 . The vortical flow 232 further advantageously sweeps the dislodged waste 304 upwards and tends to cause the waste and its carrier water to segregate from the bio-tubes 102 .
The backwash 230 mode is conducted for a variable period depending on accumulated waste 304 load that, in this embodiment, is approximately 10 minutes. A user can consult the pressure within the valve body 130 and the visible condition of the water flowing therethrough as indicated by the pressure gauge/sight glass 140 as indicia for terminating the backwash 230 mode.
Advantageously, the vortical action results in the bio-tubes 102 and the accumulated waste 304 being entrained in the circling water so as to be urged upwards to the level of the waste pipe 136 . The configuration of the backwash ports 176 is such that the water is circulated at a higher velocity in the vortical or cyclonic fashion. The higher velocity of the water results in more of the waste matter 304 being entrained in an upward motion to the level of the waste pipe 136 (FIG. 4) thereby allowing for removal of the waste material 304 . Hence, the cyclonic motion of the water as a result of the placement and configuration of the backwash assembly 170 is better able to urge the waste material 304 into the waste pipe 136 for removal from the system 300 .
Moreover, the bio-tubes 102 are preferably selected so as to be heavier than the waste material 304 and preferably have a specific gravity selected so that the bio-tubes reside on the bottom 220 of the container 202 in the general manner illustrated in FIG. 6 . The waste material 304 generally collects near the upper surface of the layer of bio-tubes 102 comprising the filtration media and is thus located more proximal to the waste pipe 136 . Further, since the bio-tubes 102 are generally heavier than the waste material 304 , when the system 300 is being backwashed, the waste material 304 is generally entrained in the water above the bio-tubes 102 . This allows for flushing of the waste material 304 while reducing the loss of the bio-tubes 102 during the backwashing 230 process.
Following conclusion of the backwash 230 mode, the valve handle 126 is positioned to select a rinse 240 mode. In the rinse 240 mode, water enters the inlet pipe 132 , passes through the valve body 130 and enters the container 202 through the media screen 144 . The water then exits through the intake tube assembly 172 , the stand pipe 146 and out the waste pipe 136 . The rinse 240 mode settles the bio-tubes 102 in preparation for return to the filtering mode 200 previously described.
The fish pond filter system 100 further comprises a waste 250 , re-circulate 260 , and closed 270 modes selectable by positioning the valve handle 126 as shown in FIG. 8 . The waste 250 mode directs water flow into the inlet pipe 132 , through the valve body 130 and out the waste pipe 136 , bypassing the container 202 and filtering 200 process previously described. The waste 250 mode is used to lower the level of the fish pond 300 without filtering 200 the water. The re-circulate 260 mode directs water into the inlet pipe 132 , through the valve body 130 , and back out the outlet pipe 134 , bypassing the filtering 200 process previously described. The re-circulate 260 mode is used to circulate water in the fish pond 300 without running it through the filtering 200 process previously described. The closed 270 mode blocks water flow into the inlet pipe 132 . The closed 270 mode is used to shut off the fish pond filter system 100 from the rest of the fish pond 300 .
A side view of a typical installation of the fish pond filter system is shown in FIGS. 9 and 10. The fish pond filter system 100 comprises a pump 320 as shown in FIG. 9 . The pump 320 is connected between the fish pond 300 and the inlet pipe 132 and is adapted to pump water from the fish pond 300 to the inlet pipe 132 when supplied with electrical or mechanical power in a well known manner. The pre-filter 306 screens out larger waste 304 particles such as leaves, sticks, or dead fish 302 which are approximately greater than ⅛″ in two dimensions that could damage the pump 320 or plug up the fish pond filter system 100 . In the embodiment shown in FIG. 10, the waste pipe 136 extends to discharge unreacted waste 304 and water in the backwash mode 230 as previously described.
The fish pond filter system 100 employs naturally occurring heterotrophic bacteria 310 as part of the filter mode 200 . The heterotrophic bacteria 310 metabolizes at least some of the biological waste 304 that is generated and accumulated in the fish pond 300 and thus reduces the chemical treatment that a user of the fish pond filter system 100 needs to employ to maintain the health and appearance of the fish pond 300 . Thus a user of the fish pond filter system 100 reduces the inconvenience and health risks associated with handling chemicals.
The bio-tubes 102 of the present invention provide a high surface area-to-volume ratio and thus can support an adequately large population of heterotrophic bacteria 310 in a relatively small container 202 . The shape and differing sizes of the bio-tubes 102 of the fish pond filter system 100 are configured to inhibit uniform stacking and channeling during the filter mode 200 . Other known filter media have a relatively low surface area-to-volume ratio and thus require larger, more obtrusive systems or are configured such that they tend to uniformly stack during filtering, which leads to the creation of channels within the filter media, which reduces the effectiveness of a filter system so equipped. By minimizing the size of the container 202 needed to adequately filter a given size of fish pond 300 , the fish pond filter system 100 minimizes the purchase cost, installation time and cost, and aesthetic impact of the fish pond filter system 100 while still efficiently and reliably filtering the fish pond water.
The fish pond filter system 100 also includes a backwash mode 230 , which creates a vortical flow pattern within the filter media container 202 . The vortical flow efficiently dislodges accumulated waste 304 trapped within the bio-tubes 102 and entrains the waste 304 out of the fish pond filter system 100 . The efficient backwash mode 230 , employing the vortical flow, takes less time to clean the filter media and directs less wastewater out of the system 100 . Thus, the fish pond filter system 100 furthers saves time and money for a user.
Although the preferred embodiments of the present invention have shown, described and pointed out the fundamental novel features of the invention as applied to those embodiments, it will be understood that various omissions, substitutions and changes in the form of the detail of the device illustrated may be made by those skilled in the art without departing from the spirit of the present invention. Consequently, the scope of the invention should not be limited to the foregoing description but is to be defined by the appended claims. | A system for filtering and treating waste generated or collected in the water of a fish pond. The system includes a pump, pre-filter, piping, a valve assembly, and a filter media container enclosing a plurality of discrete filter media. The filter media are generally hollow, plastic structures with a plurality of external ribs and internal dividing walls. The filter media has a high surface area-to-volume ratio and can support a high volumetric density of naturally occurring heterotrophic bacteria. The heterotrophic bacteria establish colonies on the internal and external surfaces of the filter media and biologically metabolize waste that is trapped on the media. The bacterial metabolization transforms much of the waste to an aesthetically and biologically neutral form thereby reducing the need for chemical treatment of the pond water. The system includes a backwashing mode to agitate and remove unreacted waste from the system and direct the waste stream out of the system, preferably to be used as fertilizer. |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 12/857,835 filed Aug. 17, 2010, and issued as U.S. Pat. No. 8,652,606 Feb. 18, 2014, the entire disclosure of which is incorporated by reference herein.
BACKGROUND INFORMATION
1. Field
This disclosure generally relates to composite structures, especially fiber reinforced resin laminates, and deals more particularly with a hybrid composite having a composite-to-metal joint, as well as to a bonded metal laminate used in the joint.
2. Background
Bonding techniques are often used to assemble composite structures. In applications where the composite structure also requires fasteners, the local thickness or gauge of the structure surrounding the fastener may need to be increased in order to withstand loads transmitted through the fastener joint. As the local thickness of the structure increases, the fastener may need to be lengthened, thereby adding weight to the structure. Additionally, the increased local thickness of the structure may increase the eccentricity of the load path across the fastener joint, which may place undesired bending loads on the fastener.
One solution to the problems mentioned above consists of attaching metal fittings to the composite structure in the area of the fasteners. These metal fittings may be formed of titanium or similar metals that may not substantially chemically react with carbon fiber reinforced composites in which they are in contact. Titanium fittings, however may be relatively expensive, particularly when it is necessary to form them into complex shapes.
Accordingly, there is a need for a composite resin-to-metal joint that may be used to connect substantially all metal fittings with substantially all composite resin structures, which is relatively inexpensive and easy to manufacture, and which may withstand loads transferred around fastener connection points. There is also a need for a composite resin-to-metal joint that substantially avoids chemical reactions between the all metal fitting and the all composite resin structure. Also, there is a need for a composite-to-metal joint that may reduce residual stresses in the joint following a thermal curing. Further there is a need for a bonded metal laminate that may be used in the joints and in other applications where additional strength and durability are required.
SUMMARY
The disclosed embodiments provide a hybrid-type composite structure that includes a fiber reinforced resin composite-to-metal joint that may be used to connect a substantially all-metal fitting with a substantially all composite resin structure or a different structure. The joint provides a transition between the composite and metallic structures that is suitable for use in higher performance applications, such as aerospace vehicles. This transition from a substantially all composite to a substantially all metal material may reduce or eliminate the possibility of corrosion and/or problems stemming from eccentricity. During lay-up of the composite structure, relatively thin, flexible metal sheets of metal are substituted for a number of composite plies, and the transition from composite plies to metal sheets occurs at staggered locations so as to provide adequate load transfer from the composite portion to the metal portion. The staggered transition results in an interleaving between the composite plies and the metal sheets and creates multiple bond lines that may reduce the occurrence and/or propagation of cracks or disbonds in the joint. An adhesive placed between the metal sheets binds and unitizes the sheets into a nearly solid metal fitting.
The composite-to-metal joint may be configured as a finger type, step lap joint in order to reduce residual stresses that may be induced in the joint during cooling of the hybrid composite structure following a thermal cure cycle. The bonded metal sheets employed in the joint form a metal laminate that may be used in a variety of other applications, and which exhibits improved performance compared to monolithic metal structures. In some applications, the composite-to-metal joint utilizing the metal laminate may be used to reinforce an edge of a composite structure or to reinforce an area of a composite structure around fasteners. Additional advantages of the disclosed composite-to metal joint may include improved joint robustness, reduced weight, improved safety, less maintenance, weight savings, improved inspectability, strength improvements, and reduced manufacturing costs. The disclosed metal laminate used in the composite-to-metal joint may enable a structure to have weight and fatigue characteristics of composite resin laminates while providing the strength and durability of a metal structure. The composite-to-metal joint may reduce or avoid the need for machined end-fittings for some composite resin structure applications. A shorter bond length resulting from use of the disclosed joint may minimizes residual (or cured in) stresses due to CTE (coefficient of thermal expansion) mismatch between the metallic and composite materials forming the joint, and may also benefit the in-service performance of the joint where service temperatures can vary 225 degrees F. or more.
According to one disclosed embodiment, a metal structure is provided that exhibits improved strain performance. The metal structure comprises at least a first metal laminate including a first plurality of metal sheets bonded together. The metal structure further comprises a plurality of layers of a bonding adhesive forming adhesive bonds between the metal sheets. The metal laminate includes at least one through hole therein adapted to receive a fastener. The metal structure may further comprise a second metal laminate including a second plurality of metal sheets bonded together, and at least one fastener joining the first and second metal laminates together.
According to another disclosed embodiment, an integrated attachment fitting is provided for a structure. The attachment fitting comprises a composite resin portion, a metal portion, and a composite-to-metal joint between the composite resin portion and the metal portion. The composite resin portion includes a plurality of fiber reinforced resin plies, and the metal portion includes a plurality of metal sheets bonded together. The composite-to-metal joint includes overlapping steps between the fiber reinforced resin plies and the metal sheets. The composite-to-metal joint may comprise a finger joint. In one application, the structure may comprise an aircraft vertical stabilizer, and the metal portion may be a metal laminate attachment lug having a through-hole therein adapted to receive a bolt for attaching the lug to an aircraft fuselage. The composite resin portion forms part of the aircraft vertical stabilizer. In another application, the structure may be an aircraft wing, and the metal portion is a metal laminate having a plurality of through-holes therein adapted to receive fasteners for attaching the wing to a center wing box on an aircraft fuselage. The composite-to-metal joint may be one of a finger lap joint, a tapered lap joint, a vertical lap joint, and a lap joint having a variable overlap. In a further application, the structure may be a rotor blade having a root adapted to be attached to a rotating hub, and the metal portion includes a metal laminate located at the root, wherein the metal laminate has a through-hole therein adapted to receive a retention bolt for retaining the rotor blade on the rotating hub. In still another application, the composite-to-metal joint is an overlapping splice joint adapted to join two fuselage sections of an aircraft.
According to a further embodiment, a fastener reinforcement is provided for reinforcing an area of a multi-ply composite structure. The fastener reinforcement comprises a metal laminate including a plurality of metal sheets bonded together, wherein the metal laminate has a through-hole adapted to receive a fastener therein. The fastener reinforcement further comprises a composite-to-metal joint between the metal laminate and the composite structure. The meal sheets have edges that are interleafed with the plies of the composite structure.
According to another disclosed embodiment, a method is provided of fabricating a composite structure, comprising assembling at least a first stack of metal sheets, and laminating the first stack of metal sheets together by placing a layer of adhesive between each of the metal sheets. The method further comprises assembling a second stack of metal sheets, laminating the second stack of metal sheets together by placing a layer of adhesive between each of the metal sheets, and fastening the first and second stacks of metal sheets by passing fasteners through the first and second stacks of metal sheets.
According to still another embodiment, a method is provided of reinforcing an area of a composite laminate containing a fastener passing through the thickness of the composite laminate. The method comprises integrating a multi-ply metal laminate into the area of the composite laminate to be reinforced, and forming a through-hole in the metal laminate for receiving the fastener. Integrating the metal laminate is performed by interleafing plies of the metal laminate with plies of the composite laminate to form a finger joint between the metal laminate and the composite laminate. According to a further disclosed embodiment, a method is provided of reinforcing an edge of a multi-ply fiber reinforced resin laminate. The method comprises joining a metal laminate to the resin laminate along the edge of the resin laminate. Joining the metal laminate to the resin laminate is performed by interleafing edges of the plies of the metal laminate and the resin laminate. The interleafing may be performed in a manner to form a finger joint between the metal laminate and the resin laminate.
BRIEF DESCRIPTION OF THE ILLUSTRATIONS
FIG. 1 is an illustration of a sectional view of a composite structure having a composite-to-metal joint.
FIG. 2 is an illustration of a perspective view of the composite structure including the composite-to-metal joint.
FIG. 3 is an illustration of a perspective view of the area designated as FIG. 3 in FIG. 2 .
FIG. 4 is an illustration of a cross sectional view of the joint, better showing interleaving between composite plies and the metal sheets.
FIG. 5 is an illustration of a cross sectional view of two separated layers of the joint shown in FIG. 4 , also showing the application of a film adhesive on the metal sheets.
FIG. 6 is an illustration of an enlarged, cross sectional view of a portion of the joint formed by the two layers shown in FIG. 5 .
FIG. 7 is an illustration of a broad flow diagram of a method of making a composite structure having the composite joint shown in FIGS. 2-4 .
FIG. 8 is an illustration of a flow diagram showing additional details of the method shown in FIG. 7 .
FIG. 9 is a flow diagram of another method of making a composite structure having the composite joint shown in FIGS. 2-4 .
FIG. 10 is an illustration of a perspective view of a composite-to-metal finger joint having a relatively shallow double taper.
FIG. 11 is an illustration similar to FIG. 10 but showing a composite-to-metal finger joint having a relatively steep taper.
FIG. 12 is an illustration of a sectional view of a composite-to-metal joint having a single taper.
FIG. 13 is an illustration similar to FIG. 12 but illustrating a composite-to-metal joint having a reversed single taper.
FIG. 14 is an illustration of a cross sectional view of a composite-to-metal finger joint having a symmetric double taper.
FIG. 15 is an illustration similar to FIG. 14 but illustrating a symmetric reversed double taper finger joint.
FIG. 16 is an illustration of a cross sectional view of a vertical composite-to-metal finger joint.
FIG. 17 is an illustration of a cross sectional view of a composite-to-metal finger joint having variable overlap between the plies.
FIG. 18 is an illustration of a plan view of a composite structure having a laminated metal reinforcement around a fastener.
FIG. 19 is an illustration of a cross sectional view taken along the line 19 - 19 in FIG. 18 .
FIG. 20 is an illustration of an exploded, perspective view of a typical aircraft employing composite-to-metal joints.
FIG. 21 is an illustration of a sectional view taken along the line 21 - 21 in FIG. 20 , showing a typical composite-to-metal joint between fuselage sections.
FIG. 22 is an illustration of a perspective view of a composite-to-metal joint between an aircraft wing and a center wing box.
FIG. 23 is an illustration of a perspective view of a portion of a skin of the wing box shown in FIG. 22 .
FIG. 24 is an illustration of the area designated as FIG. 24 in FIG. 22 .
FIG. 25 is an illustration of a perspective view of an aircraft vertical stabilizer, parts being broken away in section for clarity.
FIG. 26 is an illustration of a side view showing attachment of the stabilizer shown in FIG. 25 to a fuselage using a lug containing a composite-to-metal joint.
FIG. 27 is an illustration of a side view of a forward portion of an aircraft, illustrating a hatchway reinforced by a composite-to-metal joint.
FIG. 28 is an illustration of a sectional view taken along the line 28 - 28 in FIG. 27 .
FIG. 29 is an illustration of a perspective view of a helicopter.
FIG. 30 is an illustration of a perspective view of a rotor assembly of the aircraft shown in FIG. 29 .
FIG. 31 is an illustration of the area designated as FIG. 31 in FIG. 30 .
FIG. 32 is an illustration of a cross sectional view of a bonded metal laminate.
FIG. 33 is an illustration of a cross sectional view of two bonded metal laminates joined together by fasteners.
FIG. 34 is a flow diagram showing a method fabricating the bonded metal laminate shown in FIG. 32 .
FIG. 35 is an illustration of a flow diagram of a method of reinforcing a composite laminate containing a fastener.
FIG. 36 is an illustration of a flow diagram of aircraft production and service methodology.
FIG. 37 is an illustration of a block diagram of an aircraft.
DETAILED DESCRIPTION
Referring first to FIG. 1 , a hybrid composite structure 20 includes a composite resin portion 22 joined to a metal portion 24 by a transition section 25 that includes a composite-to-metal joint 26 . In the illustrated example, the composite structure 20 is a substantially flat composite sheet, however depending upon the application, the structure 20 may have one or more curves, contours or other geometric features. For example, composite structure 20 may comprise an inner and/or outer contoured skin 20 of an aircraft (not shown) which is secured to a frame portion 28 of the aircraft by means of a lap joint 30 and fasteners 32 which pass through the composite structure 20 into the frame portion 28 .
The frame portion 28 may comprise a composite, a metal or other rigid material, and the metal portion 24 of the structure 20 may serve as a rigid metal fitting 24 that is suited to transfer a range of loads and types of loadings between the frame portion 28 and the composite portion 20 . As will be discussed below in more detail, the metal portion 24 may comprise any of various metals such as, without limitation, titanium that is substantially non-reactive to and compatible with the composite portion 22 and the frame portion 28 . In one practical embodiment for example, and without limitation, the composite resin portion 22 may comprise a carbon fiber reinforced epoxy, the metal portion 24 may comprise a titanium alloy, and the frame 28 may comprise an aluminum alloy or a composite. The transition section 25 and the joint 26 are strong enough to carry the typical range and types of loads between the composite resin portion 22 and the metal portion 24 , including but not limited to tension, bending, torsion and shear loads. Although the illustrated transition section 25 and joint 26 are formed between an all composite resin portion 22 and the all metal portion 24 , it may be possible to employ them to join two differing composite structures (not shown) or two differing metal structures (not shown).
Referring to FIGS. 1-4 , a layup of composite material plies 35 is terminated at a interface location 39 referred to later herein as a transition point 39 , where a metal sheet or ply 37 of the substantially the same thickness as the composite material plies 35 continues to the metal edge 24 a of the metal portion 24 , and the layup is repeated with a composite-to-metal interface 39 that is staggered toward the metal edge 24 a from the prior interface location 39 and includes a ply of structural metal adhesive 45 (see FIGS. 5 and 6 ) between the metal plies 37 , with the next composite-to-metal interface 39 staggered away from the metal edge 24 a to produce a nested splice 27 . This staggered interface stacking, which produces nested tabs 29 (see FIG. 3 ), is continued to the full thickness of the hybrid composite structure 20 with none of the composite plies 35 extending fully to the metal edge 24 a of the all metal portion 24
Referring now also to FIGS. 2-4 , the composite portion 22 of the structure 20 comprises a laminated stack 34 of fiber reinforced resin plies 35 , and the metal portion 24 of the structure 20 comprises a stack 36 of metal sheets or plies 37 that are bonded together to form a laminated, substantially unitized metal structure. As shown in FIGS. 5 and 6 , the composite plies 35 and the metal sheets 37 are arranged in layers 38 . Each of the layers 38 comprises one or more of the composite plies 35 in substantially edge-to-edge abutment with one of the metal sheets 37 . Thus, each of the layers 38 transitions at a point 39 from a composite i.e. composite resin plies 35 , to a metal, i.e. metal sheet 37 .
The transition points 39 are staggered relative to each other according to a predetermined lay-up schedule such that the plies 35 and the metal sheets 37 overlap each other in the transition section 25 ( FIG. 1 ). Staggering of the transition points 39 creates multiple bond lines that may reduce the occurrence and/or propagation of cracks or disbonds in the joint 26 . The staggering of the transition points 39 also results in a form of interleaving of the composite plies 35 and the metal sheets 37 within the joint 26 which forms a nested splice 27 between the all composite portion 22 and the all metal portion 24 . This nested splice 27 may also be referred to as a finger bond 26 , a finger joint 26 or a multiple step lap joint 26 . The adjacent ones of the transition points 39 are spaced from each other in the in-plane direction of the structure 20 so as to achieve a bonded joint 26 that exhibits optimum performance characteristics, including strength and resistance to disbonds and propagation of inconsistencies such as cracks. In the illustrated example, the nested splice 27 forming the joint 26 is a form of a double finger joint in which the transition points 39 are staggered in opposite directions from a generally central point 55 of maximum overlap. However, as will be discussed blow in more detail, other joint configurations are possible including but not limited to a single finger joint in which the multiple transition points 39 are staggered in a single direction.
The composite plies 35 may comprise a fiber reinforced resin, such as without limitation, carbon fiber epoxy, which may be in the form of unidirectional prepreg tape or fabric. Other fiber reinforcements are possible, including glass fibers, and the use of non-prepreg materials may be possible. The composite plies 35 may have predetermined fiber orientations and are laid up according to a predefined ply schedule to meet desired performance specifications. As previously mentioned, the bonded sheets 37 may comprise a metal such as titanium that is suitable for the intended application. In the illustrated example, the stack 36 of metal sheets 37 has a total thickness t 1 which is generally substantially equal to the thickness t 2 of the laminated stack 34 of plies 35 . In the illustrated example however, t 2 is slightly greater than t 1 by a factor of the thickness of several overwrap plies 43 on opposite sides of the stack 37 .
The use of a multiple step lap joint 26 may increase the bond area along the length of the transition section 25 , compared to a scarf type joint or other types of joints which may require a longer length transition section 25 in order to achieve a comparable bond area between the composite resin portion 22 and the metal portion 24 . Following thermal curing, cooling of the hybrid composite structure 20 may result in residual stresses in the joint 26 due to a mismatch between the coefficient of thermal expansion (CTE) of the composite resin portion 22 and the metal portion 24 . The amount of thermal expansion during curing is a function of the CTE of the composite resin portion 22 and the metal portion 24 , as well as the length of the transition section 25 . Use of the step lap joint 26 , rather than a scarf type or other type of joint may reduce the amount of these residual stresses because of the reduction in the length of the transition section 25 that is needed to obtain a preselected amount of bond area between the two portions 22 , 24 of the joint 26 . Reduction of the length of the transition section 25 may also reduce residual stresses in the joint 26 after the aircraft is placed in service where large temperature extremes may be encountered during either normal or extreme operations.
FIGS. 5 and 6 illustrate details of two adjoining layers 38 of the joint 26 shown in FIGS. 2-4 . In this example, each layer 38 comprises four plies 35 having a collective total thickness T 1 . The individual metal sheets 37 of the adjacent layers 38 are bonded together by means of a layer of structural adhesive 45 , which may comprise a commercial film adhesive or other forms of a suitable adhesive that is placed between the metal sheets 36 during the lay-up process.
The combined thickness of each metal sheet 37 and one layer of adhesive 45 represented as T 2 in FIG. 5 is substantially equal to the thickness T 1 of the composite plies 35 in the layer 38 . Although not shown in the Figures, a thin film of adhesive may be placed between the plies 35 to increase the interlaminar bond strength. In one practical embodiment, titanium alloy metal sheets may be used which each have a thickness of approximately 0.0025 inches, the film adhesive 45 may be approximately 0.005 inches thick, and four composite carbon fiber epoxy plies 35 may be used in each layer 38 having a collective total thickness of about 0.30 inches. Depending on the application, the use of metals other than titanium may be possible. The distance between adjacent transition points 39 , and thus the length of the overlap between the layers 38 , as well as the thickness and number of composite plies 35 and the thickness of the metal sheets 37 will depend on the requirements of the particular application, including the type and magnitude of the loads that are to be transmitted through the joint 26 , and possibly other performance specifications. It should be noted here that the bonded metal sheets 37 is not limited to use in a composite metal joint 26 discussed above. As will be discussed later below, a metal structure comprising bonded metal sheets 37 has a variety of other applications because of the superior strain performance it may exhibit, compared to monolithic metal structures.
The differing layers 38 of the joint 26 between the two differing materials of the composite and metal portions 22 , 24 respectively ( FIG. 1 ), render the structure 20 well suited to nondestructive evaluations of bond quality using embedded or mounted sensors (not shown). Ultrasonic structural waves (not shown) may be introduced into the structure 20 at the edge of the metal portion 24 , at the composite portion 22 or in the transition section 25 . These ultrasonic waves travel through what amounts to a waveguide formed by the metal sheets and the interfaces (not shown) between the composite plies 35 and the metal sheets 37 . MEMS-based (microelectromechanical) sensors, thin piezo-electric sensors (not shown) or other transducers placed in the structure 20 may be used to receive the ultrasonic structural waves for purposes on analyzing the condition of the bondlines in the joint 26 .
Referring now to FIG. 7 , one method of making the composite structure 20 comprises forming a multi-layer composite lay-up as shown at 65 . Forming the lay-up includes laying up a composite resin portion 22 at step 67 , and laying up a metal portion 24 at 69 . The step 65 of forming the layup further includes forming a composite-to-metal joint between the composite resin portion and the metal portion of the lay-up, shown at 71 .
FIG. 8 illustrates additional details of the method shown in FIG. 7 . Beginning at step 40 , individual metal sheets 37 are trimmed to a desired size and/or shape. Next at 42 , the surfaces of the metal sheets 37 are prepared by suitable processes that may include cleaning the sheets 37 with a solvent, drying them, etc. Then at 44 , the lay-up is assembled by laying up the metal sheets 36 and the composite plies 35 in a sequence that is determined by a predefined ply schedule (not shown) which includes a predetermined staggering of the transition points 39 between the plies 35 and the metal sheet 37 in each layer 38 .
During the lay-up process, the metal sheets 37 are sequenced like plies into the lay-up, much like composite plies are sequenced into a lay-up in a conventional lay-up process. As shown at step 46 , adhesive may be introduced between the metal sheets 37 in order to bond them together into a unitized metal structure. Similarly, although not shown in FIG. 8 , a bonding adhesive may be introduced between the individual composite plies 35 in order to increase the bond strength between these plies 35 . Next, at 48 , the lay-up may be compacted using any of several known compaction techniques, such as vacuum bagging following which the lay-up is cured at step 50 using autoclave or out-of-autoclave curing processes. At step 52 , the cured composite structure 20 may be trimmed and/or inspected, as necessary.
FIG. 9 illustrates still another embodiment of a method of making a hybrid composite part 20 . The method begins at step 73 with laying at least one composite ply 35 that is terminated at an interface location 39 on a suitable layup tool (not shown). At 75 , an adjacent metal ply 37 is laid up which is substantially the same thickness as the adjacent composite material ply 35 . As shown at 77 , the layup process is repeated with a composite-to-metal interface 39 that is staggered toward the metal edge 24 a of the part 20 from the transition point 39 . A 79 , a ply 45 of structural adhesive is laid between the metal plies 37 . Steps 73 - 79 are repeated successively to produce a nested splice 27 and a staggered interface stacking forming nested tabs 29 to the full thickness of the hybrid part 20 , with none of the composite plies 35 extending fully to the metal edge 24 a of the part 20 . Although not shown in FIG. 9 , the completed layup is vacuum bagged processed to remove voids, and is subsequently cured using any suitable curing method.
The composite-to-metal joint 26 previously described may be constructed in any of a variety of joint configurations in which the composite material plies 35 are interleafed with the metal plies 37 . For example, referring to FIG. 10 , the transition section 25 of the hybrid composite structure 20 may include a composite-to-metal joint 26 having a relatively shallow taper resulting from lengths L of overlap between the composite and metal plies 35 , 37 that are relatively long. In the example shown in FIG. 10 , the composite-to-metal joint 26 is a double tapered finger joint. In comparison, as shown in FIG. 11 , shorter lengths L of the overlap between the composite and metal plies 35 , 37 results in a double tapered finger joint 26 that has a relatively steep taper, in turn resulting in a shorter transition section 25 between the composite resin and metal portions 22 , 24 respectively. The length L of the overlap may be optimized for the particular application.
FIGS. 12-17 illustrate other examples of composite-to-metal joint 26 configurations. In one alternative, the composite-to-metal joint 26 may comprise a double tapered finger joint 26 that includes a tapered or layered multi-ply construction above and below a composite-to-metal interface 39 , wherein one or more overlap lengths, e.g., lengths L, may be chosen or optimized relative to a particular real estate constraint, area, or transitional stress or strain requirement. In one example, the real estate constraint or area may require a shorter transition section, for instance, between the composite resin and metal portions. In some applications, a transitional stress or strain requirement may require progressively less stress or strain along a portion of the structure. For example, FIG. 12 illustrates a single taper lap joint 26 , while FIG. 13 illustrates a single reverse taper lap joint 26 . In FIG. 14 , the joint 26 is configured as a double tapered, substantially symmetrical, staggered finger lap joint while FIG. 15 illustrates a reverse double tapered finger lap joint 26 . The use of the staggered finger lap joints 26 shown in FIGS. 14 and 15 may be preferred in some applications because the joint may have a CTE interface that is less than an equivalent step lap joint of a longer transition section 25 ( FIG. 10 ). In FIG. 16 , the composite-to-metal joint 26 takes the form of a vertical lap finger joint, while FIG. 17 illustrates a composite-to-metal joint 26 in which the overlap between the composite and the metal plies 35 , 37 is variable through the thickness of the joint 26 .
Attention is now directed to FIGS. 18 and 19 which illustrate a hybrid composite structure 20 comprising a composite resin portion 22 and a metal portion 24 that forms a metal laminate reinforcement 76 around a fastener passing through the hybrid composite structure 20 . The metal portion 24 forming the metal laminate reinforcement 76 comprises a stack 36 of metal sheets or plies 37 that are bonded together, similar to the metal laminates previously described. The metal laminate reinforcement 76 is connected to the surrounding composite resin portion 22 by a circumferential composite-to-metal joint 26 , as shown in FIG. 19 which, in the illustrated embodiment, comprises a double tapered finger lap joint, similar to that shown in FIGS. 4 , 10 , and 14 . In one alternative, staggered finger lap joints may include a transition region where one or more edges of composite material plies, metal plies, or combinations thereof may have varying levels of overlap or non-overlap to achieve or meet a desired CTE interface coefficient, a desired real estate constraint, an area constraint, or transitional stress or strain requirement. In one example, real estate constraint or area may require a shorter transition section, for instance, between the composite resin and metal portions or metal plies. In one example, transitional stress or strain requirement may require progressively less stress or strain along a portion of the structure.
The metal laminate reinforcement 76 includes a central through-hole 85 through which the fastener 78 passes. The fastener 78 may comprise for example and without limitation, a bolt or rivet 78 having a body 78 a and heads 78 b and 78 c . Although not shown in the drawings, the fastener 78 may be used to attach a structure to the composite structure 20 , or to secure the hybrid composite structure 20 to another structure. The metal laminate reinforcement 76 functions to strengthen the area surrounding the fastener 78 and may better enable the composite structure 20 to carry loads in the area of the fastener 78 .
The composite-to-metal joint 26 previously described may be employed in a variety of applications, including those in the aerospace industry to join composite structures, especially in areas where a composite structure is highly loaded. For example, referring to FIG. 20 , an airplane 80 broadly comprises a fuselage 82 , left and right wings 84 , a vertical stabilizer 92 and a pair of horizontal stabilizers 94 , and a wing box 108 . The airplane 80 may further include a pair of engines 88 surrounded by engine nacelles 86 , and landing gear 90 .
The composite-to-metal joint 26 previously described may be employed to join or mount any of the components shown in FIG. 20 . For example, composite-to-metal joints 26 may be employed to mount the wings 84 on the center wing box 108 , as will be discussed below in more detail. Similarly, a composite-to-metal joint 26 may be employed to attach the vertical stabilizer 92 and/or the horizontal stabilizers 94 to the fuselage 82 . The composite-to-metal joints 26 may be employed to mount the landing gear 90 on the wings 84 , as well as to mount engines 88 and engine nacelles 86 on pylons (not shown) on the wings 84 . Further, the disclosed composite-to-metal joint 26 may be employed to join fuselage sections 82 a together. For example, referring to FIGS. 20 and 21 , fuselage sections 82 a may be joined together by a co-bonded lap joint indicated at 96 , wherein each of the adjoining fuselage sections 82 a comprises a metal laminate stack 36 and finger overlaps 98 , 100 between composite resin and metal plies 35 , 37 respectively. In this example, the metal laminate stacks 36 of the respective fuselage sections 82 a may be joined together, as by bonding using a suitable bonding adhesive.
Referring now to FIG. 22 , each of the wings 84 ( FIG. 20 ) may be attached to the center wing box 108 by an attachment joint, generally indicated at 104 . Each of the wing 106 and the wing box 108 broadly comprises an outer skin 120 attached to spanwise extending spars 110 . The attachment joint 104 includes an attachment fitting 114 having a pair of flanges 118 that are attached by bolts 122 or other suitable fasteners to the skins 120 . The attachment joint 104 may be reinforced by C-shaped channels 112 and brackets 116 .
Referring also now to FIGS. 23 and 24 , each of the skins 120 includes a metal portion 24 that also forms an integrated attachment fitting which is connected to a composite resin portion 22 by a composite-to-metal joint 26 of the type previously described. Although not shown in FIGS. 23 and 24 , the metal portion 24 of the joint 26 is formed by laminated metal plies 37 , and the composite resin portion of the joint 26 is formed by laminated composite resin plies 35 . As particularly shown in FIG. 24 , the metal portion 24 of the joint 26 may be scarfed at 128 to receive one of the flanges 118 therein. Metal portions 24 include through-holes 124 that are aligned with the through-holes 126 in the flanges 118 of the fitting 116 . It may thus be appreciated that attachment joint 104 is reinforced by the presence of the metal portions 24 which are attached to the metal attachment fitting 114 by the bolts 122 .
FIGS. 25 and 26 illustrate another application of composite-to-metal joint 26 that may be employed to attach a vertical stabilizer 92 or similar airfoil to an aircraft fuselage 82 . As shown in FIG. 25 , the vertical stabilizer 92 may comprise a series of generally upwardly extending spars 130 connected with ribs 132 . A series of attachment lugs 134 on the bottom of the stabilizer 92 are each attached to mounting ears 138 on the fuselage 82 by means of attachment bolts 136 received within bushings 140 in the lugs 134 . Each of the lugs 134 comprises a fiber reinforced composite resin portion 22 and a metal portion 24 which may comprise a metal laminate. The composite resin portion 22 is joined to the metal portion by a composite-to-metal joint 26 of the type previously described. It may thus be appreciated that while the lug 134 is lightweight because of its predominantly composite construction, the area at which the lug 134 is attached to the fuselage 82 comprises a metal portion 24 which has a load bearing capacity that may be greater than the composite resin portion 22 .
Attention is now directed to FIGS. 27 and 28 which illustrate the use of a composite-to-metal joint 26 employed to reinforce the edges 142 of a fiber reinforced composite resin structure, which in the illustrated example comprises the skin 120 of an aircraft 80 . In this example, a fuselage hatch 141 has a periphery 142 terminating in an edge 144 ( FIG. 28 ) that is reinforced by a metal portion 24 comprising a metal laminate stack 36 . The metal portion 24 is joined to the composite skin 120 by a composite-to-metal joint 26 , of the type previously described. In this example, the edge 24 a of the metal portion 24 defines the fuselage hatch 141 opening. The composite-to-fiber joint 26 may also be used to reinforce the skin 120 around other openings, such as cockpit windows 125 and passenger windows 127 .
Referring now to FIG. 29 , the composite-to-metal joint 26 may be employed to attach components on other types of aircraft, such as, for example and without limitation, a helicopter 146 . The helicopter 146 includes a main rotor assembly 148 and a tail rotor assembly 150 . The main rotor assembly 148 includes a plurality of main rotator blades 152 , and the tail rotor assembly 150 comprises a plurality of tail rotor blades 154 . Each of the main rotor blades 152 is mounted on a rotor hub 156 secured to a rotating mast 168 that is powered by one or more engines 160 . Referring particularly to FIGS. 30 and 31 , each of the main rotor blades 152 is attached to the hub 156 by means of blade grips 164 . The root 162 of each blade 152 is held on the blade grips 164 by retention bolts 166 . Each of the blades 152 includes an elongate outer composite resin portion 22 which may be a carbon fiber epoxy composite, and a metal portion 24 that is attached to the blade grips 164 by the retention bolts 166 . Metal portion 24 of the blade 152 is connected to the outer composite resin portion by a composite-to-metal joint 26 of the type previously described. The tail rotor blades 154 shown in FIG. 29 may similarly be attached to the tail rotor assembly 150 by a composite-to-metal joint 26 .
Referring to FIG. 32 , a metal laminate 170 comprises a plurality of generally flexible metal sheets or plies 37 which are bonded together by layers 45 of a suitable adhesive to form a structure that may exhibit performance properties that are superior to a comparable monolithic metal structure. The layers 45 of adhesive may comprise a conventional film-type structural adhesive. The metal plies 37 may be formed of the same metal or may be formed of differing metals, depending on the particular application. When the metal laminate 170 is placed in tension 175 , the tension load is individually directed to each of the metal laminate plies 37 , thereby distributing the tension load generally evenly throughout the metal structure 170 . Thus, in the event of an irregularity or inconsistency in one of the metal plies 37 that may reduce the load carrying ability of the ply 37 , the reduction is limited to that particular ply and the applied tension load is redistributed to the remaining metal plies 37 which provide strain relief. In other words, sensitive areas (i.e. plies 37 ) of the metal laminate 170 that are under load locally strain and transfer the load to adjacent metal plies 37 , resulting in a form of a progressive loading of the metal laminate 170 .
The metal laminate 170 shown in FIG. 32 may be employed to form composite-to-metal joints 26 of the type previously described, but may have other applications as well. For example, referring to FIG. 33 , two generally flat metal laminates 170 a , 170 b may be attached to each other by a lap joint 172 and fasteners 178 that pass through through-holes 173 the metal laminates 170 a , 170 b . The lap joint 172 employing may exhibit characteristics that are superior to joints employing monolithic structures. The metal laminates 170 a , 170 b may form the edges of a composite structure to which the metal laminates 170 a , 170 b are joined by composite-to-metal joints 26 of the type previously described.
Referring to FIG. 34 , a method of fabricating a structure begins at 180 , with assembling at least a first stack 36 of metal sheets or plies 37 . The metal sheets or plies 37 are then laminated together at 182 by placing a layer of structural adhesive between the sheets or plies 37 which bonds and laminates the sheets or plies 37 together into a first metal laminate 170 a . Then, optionally at 184 , a second stack of metal sheets or plies 37 is assembled and laminated together at 186 into a second metal laminate 170 b . At 188 , one or more through-holes 173 are formed in the first and second laminates 170 a , 170 b . At 190 , fasteners are installed in the though-holes 173 to fasten the metal laminates 170 a , 170 b together.
Referring to FIG. 35 , selected areas of a fiber reinforced composite resin laminate structure may be reinforced by a method that begins at step 192 with assembling a metal laminate reinforcement 76 . At step 194 , composite resin plies 35 of the composite resin laminate structure are interleafed with the metal laminate plies 37 of the metal laminate reinforcement 76 to form a composite-to-metal step lap joint 26 in the area of the composite resin laminate structure to be reinforced. As previously discussed, the metal laminate reinforcement 76 may be used to reinforce an edge of the composite resin laminate structure, or to provide a metal reinforced area around a fastener 78 . Thus, optionally, at step 196 , a through-hole 85 may be formed in the metal reinforcement 76 , and at 198 , a fastener 78 may be installed in the through-hole 85 .
Embodiments of the disclosure may find use in a variety of potential applications, particularly in the transportation industry, including for example, aerospace, marine and automotive applications. Thus, referring now to FIGS. 36 and 37 , embodiments of the disclosure may be used in the context of an air10raft manufacturing and service method 200 as shown in FIG. 36 and an aircraft 202 as shown in FIG. 37 . Aircraft applications of the disclosed embodiments may include, for example, a wide variety of structural composite parts and components, especially those requiring local reinforcement and/or the use of fasteners during the assembly process. During pre-production, exemplary method 200 may include specification and design 204 of the aircraft 202 and material procurement 206 . During production, component and subassembly manufacturing 208 and system integration 210 of the aircraft 202 takes place. Thereafter, the aircraft 202 may go through certification and delivery 212 in order to be placed in service 214 . While in service by a customer, the aircraft 202 is scheduled for routine maintenance and service 216 .
Each of the processes of method 200 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.
As shown in FIG. 37 , the aircraft 202 produced by exemplary method 200 may include an airframe 218 with a plurality of systems 220 and an interior 222 . Examples of high-level systems 220 include one or more of a propulsion system 224 , an electrical system 226 , a hydraulic system 228 , and an environmental system 230 . Any number of other systems may be included. The disclosed method may be employed to fabricate parts, structures and components used in the airframe 218 or in the interior 222 . Although an aerospace example is shown, the principles of the disclosure may be applied to other industries, such as the marine and automotive industries.
Systems and methods embodied herein may be employed during any one or more of the stages of the production and service method 200 . For example, parts, structures and components corresponding to production process 208 may be fabricated or manufactured in a manner similar to parts, structures and components produced while the aircraft 200 is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages 208 and 210 , for example, by substantially expediting assembly of or reducing the cost of an aircraft 200 . Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft 202 is in service, for example and without limitation, to maintenance and service 216 .
Although the embodiments of this disclosure have been described with respect to certain exemplary embodiments, it is to be understood that the specific embodiments are for purposes of illustration and not limitation, as other variations will occur to those of skill in the art. | A composite structure comprises stacked sets of laminated fiber reinforced resin plies and metal sheets. Edges of the resin plies and metal sheets are interleaved to form a composite-to-metal joint connecting the resin plies with the metal sheets. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Ser. No. 61/447,835 filed Mar. 1, 2011, herein incorporated by reference in its entirety. This application further claims priority to related U.S. Ser. Nos. 61/447,806, 61/447,812, 61/447,824, 61/447,848, 61/447,869, and 61/447,877, each filed Mar. 1, 2011, and each being incorporated by reference herein in its entirety, as well as the six U.S. non-provisional applications filed on even date herewith and claiming priority thereto, each of which being additionally incorporated by reference herein in their entirety.
[0002] This application is further related to co-pending U.S. Ser. Nos. 61/448,117, 61/448,120, 61/448,121, 61/448,123, and 61/448,125, each filed Mar. 1, 2011, 61/594,824 filed Feb. 3, 2012, and the application entitled “Apparatus and Systems having a Rotary Valve Assembly and Swing Adsorption Processes Related Thereto” by Robert F. Tammera et al. filed on even date herewith, each being incorporated by reference herein in its entirety, as well as any U.S. non-provisional applications claiming priority thereto and presumably filed on even date herewith, each of which being additionally incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
[0003] This invention relates to a method for reducing the loss of valuable products by improving the overall recovery of a targeted product gas component in swing adsorption processes. This invention relates to swing adsorption processes, including improved processes for temperature swing adsorption (TSA) processes, pressure swing adsorption (PSA) processes, and related separations processes.
BACKGROUND OF THE INVENTION
[0004] Swing adsorption processes are well known in the art for the separation of one or more gaseous components from a gas mixture. The term “swing adsorption process” includes all swing adsorption process including temperature swing adsorption (TSA), pressure swing adsorption (PSA), partial pressure swing adsorption (PPSA), rapid cycle pressure swing adsorption (RCPSA), rapid cycle thermal swing adsorption (RCTSA), rapid cycle partial pressure swing adsorption (RCPPSA), as well as combinations of these processes such as pressure/temperature swing adsorption.
[0005] The first step in any swing adsorption process cycle is an adsorption step. In the adsorption step a gaseous feed mixture is flowed through an adsorbent bed and one or more of the components of the gaseous feed mixture are adsorbed by the adsorbent. These adsorbed components are sometimes referred to as “strongly adsorbed” components”. The non-adsorbed components are sometimes referred to as the “weakly adsorbed” components and pass through the adsorbent bed, without being adsorbed, to form a product stream. Depending on feed composition, there can be several strongly adsorbed component fronts passing through the bed, but there is always one that leads. The gas ahead of the leading front has a composition near that of the product. Behind the leading front the gas has a composition with a significant concentration of at least one of the strongly adsorbed components. In a conventional swing adsorption process, the adsorption step is stopped well before the leading front breaks-through the end of the adsorbent bed. The amount of feed that emerges from the contactor before this step is halted determines, in part, product recovery and purity. Typically, the adsorption step is stopped when the front advances to no more than about 0.75 to 0.85 of the length of the adsorption bed, thus preventing the front from breaking through the adsorption bed. This leaves a significant amount of product from the adsorption step at the end of the bed at the beginning of the regeneration cycle. Design of the regeneration cycles typically attempts to capture as much of the product as possible, but a certain amount inevitably flows into the strongly adsorbed component product streams. In some instances, as much as a third of what would have been the product remains in the bed when the adsorption cycle is stopped. Therefore, there is a need in the swing adsorption art for processes that are able to mitigate the amount of product trapped at the end of the adsorption bed and improve utilization of the full capacity of the adsorbent material utilized.
SUMMARY OF THE INVENTION
[0006] One aspect of the invention herein is a swing adsorption process for separating contaminant gas components from a feed gas mixture containing at least one contaminant gas component, which process comprises: a) conducting the feed gas mixture directly to a first adsorption bed in a swing adsorption process unit containing a plurality of adsorbent beds each having a fluid inlet end and fluid outlet end wherein the first adsorption bed has a first primary adsorption cycle defined by the period of time from the start of connecting the fluid input end of the first adsorption bed directly to said feed gas mixture to the end of connecting the fluid input end of the first adsorption bed directly to said feed gas mixture; b) retrieving a first product stream flow from the fluid outlet end of the first adsorption bed; c) fluidly connecting the fluid outlet end of the first adsorption bed with the fluid inlet end of a second adsorption bed in the swing adsorption process unit during a point in the first primary adsorption cycle so that at least a portion of the first product stream from the fluid outlet end of the first adsorption bed is passed to the fluid inlet end of the second adsorption bed at which time the second adsorption bed is in a first secondary adsorption cycle which first secondary adsorption cycle is defined by the period of time from the start of exposing the second adsorption bed to the first product stream from the fluid outlet end of the first adsorption bed to the end of exposing the second adsorption bed to the first product stream from the fluid outlet end of the first adsorption bed; d) retrieving a second product stream flow from the fluid outlet end of the second adsorption bed; e) fluidly disconnecting the fluid outlet end of the first adsorption bed with the fluid inlet end of a second adsorption bed; and f) conducting the feed gas mixture directly to the second adsorption bed wherein the first adsorption bed has a second primary adsorption cycle defined by the period of time from the start of connecting the fluid input end of the second adsorption bed directly to said feed gas mixture to the end of connecting the fluid input end of the second adsorption bed directly to said feed gas mixture, wherein the first product stream and the second product stream each have a lower mol % of the contaminant gas component than the feed gas mixture, and the beginnings and ends of the first primary adsorption cycle and the second primary adsorption cycle do not both coincide with each other.
[0007] In a preferred embodiment, the contactor can be a parallel channel contactor for use in gas separation adsorption process units, which contactors can be engineered structures containing a plurality of open flow channels, preferably oriented substantially parallel to each other as well as substantially parallel to the flow of feed gas, wherein the surface of the open flow channels can be composed of and/or can be lined with an adsorbent material selective for adsorption of at least one of the components of a gas mixture, and which open flow channels can have less than about 20 vol % of their open pore volume in pores greater than about 20 angstroms.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 hereof is a representation of one embodiment of a parallel channel contactor of the present invention in the form of a monolith directly formed from the microporous adsorbent of the present invention and containing a plurality of parallel channels.
[0009] FIG. 2 hereof is a cross-sectional representation along the longitudinal axis of the monolith of FIG. 1 .
[0010] FIG. 3 hereof is a representation of a magnified section of the cross-sectional view of the monolith of FIG. 2 showing the detailed structure of the adsorbent layer along with a blocking agent occupying some of the mesopores and macropores.
[0011] FIG. 4 hereof is a graphical representation of adsorption front management according to the prior art.
[0012] FIG. 5 hereof is a graphical representation of adsorption front management according to an embodiment of the present invention.
[0013] FIG. 6 hereof is a representation of four adsorbent beds fluidly connected in series.
[0014] FIG. 7 hereof is a graphical representation of a pressure profile from an adsorption process according to an embodiment of the present invention.
[0015] FIG. 8 hereof is a schematic representation of an adsorption process setup according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0016] All numerical values within the detailed description and the claims herein are modified by “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.
[0017] Non-limiting examples of swing adsorption processes for which the present invention can be applied include thermal swing adsorption (TSA), pressure swing adsorption (PSA), partial pressure swing adsorption (PPSA), rapid cycle pressure swing adsorption (RCPSA), rapid cycle thermal swing adsorption (RCTSA), rapid cycle partial pressure swing adsorption (RCPPSA), and combinations thereof (such as pressure/temperature swing adsorption, or PTSA). PSA can be a preferred swing adsorption process for the practice of the present invention.
[0018] Each of these swing adsorption processes can be comprised of a number of “steps” that include a number of adsorption and desorption stages that, in combination, can lead to a complete swing adsorption cycle that can be periodically repeated. Since multiple adsorbent beds are typically used, their appropriate time synchronization can lead to the continuous production of products. A complete swing adsorption cycle on a particular adsorbent bed can comprise all of the adsorption and desorption steps that are taken, beginning with the very first contacting of the feed gas mixture with a substantially adsorbate-free adsorbent and/or regenerated adsorbent bed and continuing through the last desorption stage that regenerates the adsorbent to its adsorbate-free or substantially adsorbate-free state and ready for another adsorption cycle. The desorption step can be accomplished by pressure swinging, thermally swinging, and/or purging the adsorbent bed. The name of the process type (i.e., TSA, PSA, PPSA) can be assigned by the regeneration method. The cycle includes any additional repressurizing and/or purging steps that may occur to bring the “cycle” back to the first contacting of the feed gas mixture with the adsorbate-free or substantially adsorbent-free adsorbent which has begun the “cycle”. At this point, the next swing adsorption “cycle” can be started, and the cycle subsequently repeated. Conventional swing adsorption processes are discussed by D. M. Ruthven, Principles of Adsorption and Adsorption Processes, John Wiley, NY (1984), which is incorporated herein by reference.
[0019] It is possible to remove two or more contaminants simultaneously but, for convenience, the component or components to be removed by selective adsorption can be referred to in the singular and referred to as a contaminant, contaminant gas, contaminant gas component, adsorbed component, strongly adsorbed component, or the like. All such terms are used interchangeably herein, unless otherwise indicated herein.
[0020] In prior art PSA processes, the gaseous mixture can be passed over a first adsorbent bed in a first vessel and a light component enriched product stream can emerge from the bed depleted in the contaminant component, which then remains adsorbed by the bed. After a predetermined time or, alternatively, prior to a break-through of the contaminant component is observed, the flow of the gaseous mixture can be switched to a second adsorbent bed for the purification to continue. FIG. 4 herein graphically illustrates a common operation of a PSA bed in the prior art. Here as shown in FIG. 4 a ), a desorbed adsorbent bed that has completed a cycle is ready to begin the next adsorption bed with the adsorbent substantially free of the adsorbed (or contaminant) component. As shown in FIG. 4 b ), as the adsorption cycle progresses, the adsorbent at the inlet end can have a high concentration of the adsorbed component wherein the adsorbent in the darkened portion is substantially spent (i.e., the remaining adsorption capacity in this area of the adsorption bed can be substantially close to zero). As the as the adsorption cycle progresses, as shown in FIG. 4 c ), more of the adsorption bed can become spent as the adsorption front moves through the bed. However, in the prior art, these processes can typically be stopped at a phase in the adsorption process illustrated in FIG. 4 d ). Additionally, although the front, for illustrative purposes, can be drawn as a sharp plane, the front in actuality can typically be somewhat dispersed and non-linear due to irregularities in the process and equipment. As such, in order to maintain proper contaminant specifications in the product retrieved from the adsorbent bed, the adsorption front can be controlled so as not to breakthrough the end of the adsorbent bed, and the adsorption cycle of the process can be stopped and the bed can be regenerated.
[0021] However, as can be seen illustrated in FIG. 4 d ), the adsorption cycle can be stopped after the adsorption front has reached through only about 75% to about 85% of the adsorption bed. That is, the adsorption bed can typically be utilized only to about 75% to about 85% of its full adsorption capacity. The remaining ˜15% to ˜25% can be used, e.g., as a safety buffer (at less than full adsorption capacity) to ensure that the resulting product from the adsorption cycle can remain within specifications for contaminant levels. This can result in a waste of about 15% to about 25% of the overall adsorbent capacity.
[0022] In contrast with the prior art, FIG. 5 illustrates an embodiment of the present invention. Here, the adsorption process can utilize at least two (2) separately operated adsorption beds (i.e., operated on separate cycles). This may not be a problem or additional burden, since essentially all commercial swing adsorption processes utilize at least two (2) beds since at least one (1) of the beds can be in an adsorption cycle while at least one (1) bed is in a desorption cycle. As illustrated in FIG. 5 a ), the desorbed adsorbent bed that has completed a cycle can be ready to begin the next adsorption bed with the adsorbent substantially free of the adsorbed (or contaminant) component. As shown in FIG. 5 b ), as the adsorption cycle progresses, the adsorbent at the inlet end can have a high concentration of the adsorbed component wherein the adsorbent in the darkened portion can be substantially spent. As the adsorption cycle progresses, as shown in FIG. 5 c ), more of the adsorption bed can become spent as the adsorption front moves through the bed. In the present invention, instead of ending the adsorption cycle in FIG. 5 d ), where the bed would be at about 75% to about 85% of its full adsorption capacity, the adsorption bed can be lined up to a second adsorption bed in the process, and the product stream can be taken off the end of the second adsorption bed instead of the first. It should be noted here that this second bed can be lined up at any time in the adsorption cycle of the first bed, but preferably prior to the point at which the adsorption front moves past the end of the first adsorption bed.
[0023] As can be further seen in FIG. 5 e ), the adsorption front can be controlled so as to move completely through the end of the first adsorption bed and into the second adsorption bed. At this point, the first adsorption bed can be utilized to near full capacity and then disconnected from the contaminated feed gas supply for regeneration. The contaminated feed gas supply can be switched directly to the inlet of the second adsorption bed, preferably either prior to or substantially simultaneously with the end of the first adsorbent bed's adsorption cycle. As can easily be seen from FIG. 5 , in the present invention, the adsorbent beds can be used to essentially full capacity, thereby increasing the overall system capacity with no significant impacts to overall product quality.
[0024] The term “break-through” is defined herein as the point where the product gas leaving the adsorbent bed exceeds the target specification of the contaminant component. At the break through point, the adsorbent bed can be considered “spent”, such that any significant further operation through the spent adsorption bed alone will result in off-specification product gas. As used herein, the “breakthrough” can generally coincide with the “adsorption front”, i.e., at the time breakthrough is detected at the outlet of the adsorbent bed, the adsorption front is generally located at the end of the adsorption bed
[0025] Please note that the “target specification” is any level of contaminant concentration that can be used for determining breakthrough and may be any level of contaminant concentration as set by the process control to ensure proper overall purity of the product stream from the swing adsorption process. As such the “target specification” can usually be some amount higher than the contaminant concentration of the overall resultant product stream retrieved from the process.
[0026] After the first adsorption bed is removed from the adsorption cycle, the adsorbed contaminant component can removed from the first adsorption bed by a reduction in pressure, an increase in temperature, or a combination thereof. In some embodiments, this portion can be accompanied by a reverse (counter-current) flow of gas to assist in desorbing the heavy component. As the pressure in the vessel is reduced, the contaminant component previously adsorbed in the bed can be progressively desorbed forming a contaminant product stream enriched in (i.e., has a higher mol % content of) the contaminant component as compared to the feed gas stream. When desorption is complete, the adsorbent bed can be purged with an inert gas stream, e.g., nitrogen and/or a purified stream of product gas. Purging can additionally or alternately be facilitated by the use of a higher temperature purge gas stream.
[0027] The total cycle time for the swing adsorption process represents the length of time from when the gaseous mixture is first conducted to the first adsorbent bed in a first cycle to the time when the gaseous mixture is first conducted to the first adsorbent bed in the immediately succeeding cycle, i.e., after a single regeneration of the first adsorbent bed. The use of third, fourth, fifth, etc., adsorbent beds in addition to the second adsorbent bed can serve to increase cycle time when adsorption time is short but desorption time is long.
[0028] In a preferred embodiment, the adsorbent can be incorporated into a parallel channel contactor. “Parallel channel contactors” are defined herein as a subset of adsorbent contactors comprising structured (engineered) contactors in which substantially parallel flow channels are incorporated into the structure. Parallel flow channels are described in detail in U.S. Patent Application Publication Nos. 2008/0282892 and 2008/0282886, both of which are incorporated herein by reference. These flow channels may be formed by a variety of means, and, in addition to the adsorbent material, the structure can contain other components such as support materials, heat sink materials and void reduction components. A wide variety of monolith shapes can be formed directly by extrusion processes. An example of a cylindrical monolith is shown schematically in FIG. 1 hereof. The cylindrical monolith 1 contains a plurality of parallel flow channels 3 that run the entire length of the monolith. These flow channels 3 can have diameters (channel gap) from about 5 microns to about 1000 microns, e.g., from about 50 to about 250 microns, as long as all channels of a given contactor have substantially the same size channel gap. The channels could have a variety of shapes including, but not limited to, round, square, triangular, hexagonal, and combinations thereof. The space between the channels can be occupied by the adsorbent 5 . As shown in FIG. 1 , the channels 3 can occupy about 25% of the volume of the monolith, and the adsorbent 5 can occupy about 75% of the volume of the monolith (e.g., from about 50% to about 98% of the volume). The effective thickness of the adsorbent can be defined from the volume fractions occupied by the adsorbent 5 and channel structure as:
[0000]
Effective
Thickness
Of
Adsorbent
=
1
2
Channel
Diameter
Volume
Fraction
Of
Adsorbent
Volume
Fraction
Of
Channels
[0029] FIG. 2 hereof is a cross-sectional view along the longitudinal axis showing feed channels 3 extending through the length of the monolith with the walls of the flow channels formed entirely from adsorbent 5 plus binder, mesopore filler, and heat sink material. A schematic diagram enlarging a small cross section of adsorbent layer 5 is shown in FIG. 3 hereof. The adsorbent layer 5 is comprised of microporous adsorbent or polymeric particles 7 ; solid particles (thermal mass) 9 ; that act as heat sinks, a blocking agent 13 , and open mesopores and macropores 11 . As shown, the microporous adsorbent or polymeric particles 7 can occupy about 60% of the volume of the adsorbent layer, and the particles of thermal mass 9 can occupy about 5% of the volume. With this composition, the voidage (flow channels) can be about 55% of the volume occupied by the microporous adsorbent or polymeric particles. The volume of the microporous adsorbent 5 or polymeric particles 7 can range from about 25% of the volume of the adsorbent layer to about 98% of the volume of the adsorbent layer. In practice, the volume fraction of solid particles 9 used to absorb thermal energy and limit temperature rise can range from about 0% to about 75%, preferably from about 5% to about 75% or from about 10% to about 60%. A mesoporous non-adsorbing filler, or blocking agent, 13 can fill the desired amount of space or voids left between particles so that the volume fraction of open mesopores and macropores 11 in the adsorbent layer 5 can be less than about 30 vol %, e.g., less than about 20 vol % or less than 10 vol %.
[0030] When the monolith contactor is used in a gas separation process that relies on a kinetic separation (predominantly diffusion controlled), it can be advantageous for the microporous adsorbent/polymeric particles 7 to be substantially the same size. It can be preferred for the standard deviation of the volume of the individual microporous adsorbent/polymeric particles 7 to be less than 100% (e.g., less than 50%) of the average particle volume for kinetically controlled processes. The particle size distribution for zeolite adsorbents can be controlled by the method used to synthesize the particles. Additionally or alternately, it can be possible to separate pre-synthesized microporous adsorbent particles by size using methods such as a gravitational settling column. Further additionally or alternately, it can be advantageous to use uniformly sized microporous adsorbent/polymeric particles in equilibrium controlled separations.
[0031] In a preferred embodiment, the swing adsorption process can be rapidly cycled, in which case the processes are referred to as rapid cycle thermal swing adsorption (RCTSA), rapid cycle pressure swing adsorption (RCPSA), and rapid cycle partial pressure swing or displacement purge adsorption (RCPPSA). For RCPSA the total cycle times can be typically less than 90 seconds, preferably less than 60 seconds, e.g., less than 30 seconds, less than 15 seconds, less than 10 seconds. For RCTSA, the total cycle times can typically be less than 600 seconds, e.g., less than 200 seconds, less than 100 seconds, or less than 60 seconds. One key advantage of RCPSA technology can be a significantly more efficient use of the adsorbent material. The quantity of adsorbent required with RCPSA technology can be only a fraction of that required for conventional PSA technology to achieve the same separation quantities and qualities. As a result, the footprint, the investment, and/or the amount of active adsorbent required for RCPSA can typically be significantly lower than that for a conventional PSA unit processing an equivalent amount of gas. In applications where CO 2 is removed from natural gas in swing adsorption processes, it can be preferred to formulate the adsorbent with a specific class of 8-ring zeolite materials that has a kinetic selectivity, though equilibrium-based adsorption can be an alternative. The kinetic selectivity of this class of 8-ring zeolite materials can allow CO 2 to be rapidly transmitted into zeolite crystals while hindering the transport of methane, so that it is possible to selectively separate CO 2 from a mixture of CO 2 and methane. For the removal of CO 2 from natural gas, this specific class of 8-ring zeolite materials can have an Si/Al ratio greater than about 250, e.g., greater than about 500, greater than about 1000, from 2 to about 1000, from about 10 to about 500, or from about 50 to about 300. As used herein, the Si/Al ratio is defined as the molar ratio of silica to alumina of the zeolitic structure. This class of 8-ring zeolites can allow CO 2 to access the internal pore structure through 8-ring windows in a manner such that the ratio of single component diffusion coefficients for CO 2 over methane (i.e., D CO2 /D CH4 ) can be greater than 10, preferably greater than about 50, greater than about 100, or greater than about 200.
[0032] Additionally or alternately, in many instances, nitrogen may desirably be removed from natural gas or gas associated with the production of oil to obtain high recovery of a purified methane product from nitrogen containing gas. There have been very few molecular sieve sorbents with significant equilibrium or kinetic selectivity for nitrogen separation from methane. For N 2 separation from natural gas, like with CO 2 , it can be preferred to formulate the adsorbent with a class of 8-ring zeolite materials that has a kinetic selectivity. The kinetic selectivity of this class of 8-ring materials can allow N 2 to be rapidly transmitted into zeolite crystals while hindering the transport of methane, so that it is possible to selectively separate N 2 from a mixture of N 2 and methane. For the removal of N 2 from natural gas, this specific class of 8-ring zeolite materials can have an Si/Al ratio from about 2 to about 1000, e.g., from about 10 to about 500 or from about 50 to about 300. This class of 8-ring zeolites can allow N 2 to access the internal pore structure through 8-ring windows in a manner such that the ratio of single component diffusion coefficients for N 2 over methane (i.e., D N2 /D CH4 ) can be greater than 5, preferably greater than about 20, greater than about 50, or greater than 100. Resistance to fouling in swing adsorption processes during the removal of N 2 from natural gas can be one advantage offered by this class of 8-ring zeolite materials.
[0033] Additionally or alternately from CO 2 , it can be desirable to remove H 2 S from natural gas which can contain from about 0.001 vol % H 2 S to about 70 vol % H 2 S (e.g., from about 0.001 vol % to about 30 vol %, from about 0.001 vol % to about 10 vol %, from about 0.001 vol % to about 5 vol %, from about 0.001 vol % to about 1 vol %, from about 0.001 vol % to about 0.5 vol %, or from about 0.001 vol % to about 0.1 vol %). In this case, it can be advantageous to formulate the adsorbent with stannosilicates, as well as the aforementioned class of 8-ring zeolites that can have kinetic selectivity. The kinetic selectivity of this class of 8-ring materials can allow H 2 S to be rapidly transmitted into zeolite crystals while hindering the transport of methane, so that it is possible to selectively separate H 2 S from a mixture of H 2 S and methane. For the removal of H 2 S from natural gas, this specific class of 8-ring zeolite materials can have a Si/Al ratio from about 2 to about 1000, e.g., from about 10 to about 500 or from about 50 to about 300. This class of 8-ring zeolites can allow H 2 S to access the internal pore structure through 8-ring windows in a manner such that the ratio of single component diffusion coefficients for H 2 S over methane (i.e., D H2S /D CH4 ) can be greater than 5, preferably greater than about 20, greater than about 50, or greater than 100. DDR, Sigma-1, and/or ZSM-58 are examples of suitable materials for the removal of H 2 S from natural gas. In some applications, it can be desired for H 2 S to be removed to the ppm or ppb levels. To achieve such extensive removal of H 2 S it can be advantageous to use a PPSA or RCPPSA process.
[0034] Other non-limiting examples of selective adsorbent materials for use in embodiments herein can include microporous materials such as zeolites, AlPOs, SAPOs, MOFs (metal organic frameworks), ZIFs (zeolitic imidazolate frameworks, such as ZIF-7, ZIF-8, ZIF-22, etc.), and carbons, as well as mesoporous materials such as amine functionalized MCM materials, and the like, and combinations and reaction products thereof. For acidic gases such as hydrogen sulfide and carbon dioxide typically found in natural gas streams, adsorbents such as cationic zeolites, amine-functionalized mesoporous materials, stannosilicates, carbons, and combinations thereof can be preferred, in certain embodiments.
[0035] It can sometimes be necessary to remove heavy (e.g., C 2+ or C 3+ ) hydrocarbons, e.g., from natural gas or gas associated with the production of oil. Heavy hydrocarbon removal may be necessary for dew point conditioning before the natural gas is shipped via pipeline or to condition natural gas before it is liquefied. Additionally or alternately, it may be advantageous to recover heavy hydrocarbons from produced gas in enhanced oil recovery (EOR) floods that employ CO 2 and nitrogen. Further additionally or alternately, it may be advantageous to recover heavy hydrocarbons from associated gas that is cycled back into an oil reservoir during some types of oil production. In many instances where it is desirable to recover heavy hydrocarbons, the gas can be at pressures in of at least 1,000 psig, e.g., of at least 5,000 psig or at least 7,000 psig. It can be advantageous in certain of these applications to use an adsorbent formulated with a zeolite having a pore size between about 5 angstroms and about 20 angstroms. Non-limiting examples of zeolites having pores in this size range can include MFI, faujasite, MCM-41, Beta, and the like, and combinations and intergrowths thereof. It can be preferred in some embodiments that the Si/Al ratio of zeolites utilized for heavy hydrocarbon removal to be from 1 to 1000.
[0036] In equilibrium controlled swing adsorption processes, most of the selectivity can be imparted by the equilibrium adsorption properties of the adsorbent, and the competitive adsorption isotherm of the light product in the micropores or free volume of the adsorbent may be disfavored. In kinetically controlled swing adsorption processes, most of the selectivity can be imparted by the diffusional properties of the adsorbent and the transport diffusion coefficient in the micropores and free volume of the adsorbent of the light species can be less than that of the heavier species. Additionally or alternately, in kinetically controlled swing adsorption processes with microporous adsorbents, the diffusional selectivity can arise from diffusion differences in the micropores of the adsorbent and/or from a selective diffusional surface resistance in the crystals or particles that make-up the adsorbent.
[0037] The present invention can additionally or alternately be applied to improve the separation of molecular species from synthesis gas. Synthesis gas can be produced by a wide variety of methods, including steam reforming of hydrocarbons, thermal and catalytic partial oxidation of hydrocarbons, and many other processes and combinations known in the art. Synthesis gas is used in a large number of fuel and chemical applications, as well as power applications such as Integrated Gasification Combined Cycle (IGCC). All of these applications have a specification of the exact composition of the syngas required for the process. As produced, synthesis gas can contain at least CO and H 2 . Other molecular components in the gas can be CH 4 , CO 2 , H 2 S, H 2 O, N 2 , and combinations thereof. Minority (or trace) components in the gas can include hydrocarbons, NH 3 , NO x , and the like, and combinations thereof. In almost all applications, most of the H 2 S should typically be removed from the syngas before it can be used, and, in many applications, it can be desirable to remove much of the CO 2 . In applications where the syngas is used as a feedstock for a chemical synthesis process, it can generally be desirable to adjust the H 2 /CO ratio to a value that can be optimum for the process. In certain fuel applications, a water-gas shift reaction may be employed to shift the syngas almost entirely to H 2 and CO 2 , and in many such applications it can be desirable to remove the CO 2 .
[0038] The following is a logic table of the steps in a complete cycle for an embodiment of a four adsorbent bed configuration utilizing the process of the present invention, and as illustrated in FIG. 6 hereof.
[0000]
Bed
Time
1
FA
FA
FA
FA
FA
BD
BD
BD
BD
RG
RG
RP
RP
RP
RP
FB
FB
FB
FB
FB
2
FB
FB
FB
FB
FB
FA
FA
FA
FA
FA
BD
BD
BD
BD
RG
RG
RP
RP
RP
RP
3
RG
RP
RP
RP
RP
FB
FB
FB
FB
FB
FA
FA
FA
FA
FA
BD
BD
BD
BD
RG
4
BD
BD
BD
BD
RG
RG
RP
RP
RP
RP
FB
FB
FB
FB
FB
FA
FA
FA
FA
FA
[0039] In the above table, FA is the primary feed/adsorption step; BD is the blow-down/depressurization step; RG is the adsorbent regeneration step; RP is the adsorbent bed repressurization step; and FB is the secondary feed/adsorption step. Following the above sequence with respect to the four adsorbent beds shown in FIG. 6 hereof, once a first cycle is completed in all four adsorbent beds, the adsorption front can be allowed to break through the adsorbent bed undergoing an adsorption step, can be passed to the next downstream adsorbent bed that has just undergone regeneration and repressurization, and can then perform an adsorption step on the product stream from the next previous adsorbent bed. This can mitigate the amount of product trapped at the end of the adsorbent bed by allowing the entire product stream coming out of an adsorbent bed to flow into a next bed to continue adsorption. In certain embodiments, the number of adsorbent beds required for the practice of the present invention can be equal to the number of discrete steps in a cycle.
[0040] Once the adsorption front has moved into the next downstream adsorbent bed, the pressure in the adsorbent bed can then be reduced, preferably in a series of blow-down steps in a co-current or counter-current and can be performed with or without a purge gas stream to the final target gas recovery pressure. Pressure reduction can preferably occur in less than 8 steps, e.g., in less than 4 steps, with target species being recovered in each step. In one preferred embodiment, the pressure can be decreased by a factor of approximately three in each step. Additionally or alternately, the depressurization can be conducted counter-currently and/or, during the depressurizing step, a purge gas can be passed counter-current (from product end to feed end) through the adsorbent bed. Further additionally or alternately, the purge gas can be a so-called “clean gas”. By “clean gas” is meant a gas that is substantially free of target gas components. For example, if the target gas is an acid gas, then the clean gas can be a stream substantially free of acid gases such as H 2 S and CO 2 (e.g., containing less than 5 mol % of combined H 2 S and CO 2 , or less than 1 mol %). An example of a preferred clean gas could be the product gas itself When the current invention is utilized for the removal of acid gas from a natural gas stream, the “clean gas” can be comprised of at least one of the hydrocarbon product streams, e.g., of C 3− hydrocarbons or of methane. Alternately, a separate “clean gas” can be used, e.g., comprised of nitrogen.
[0041] Regeneration of the adsorbent bed can occur during this depressurization step. During regeneration, the strongly adsorbed (contaminant) component or components can be desorbed from the contactor. After an adsorbent bed is depressurized and regenerated by removal of the contaminant gas components, it can preferably be repressurized prior to the beginning of the next adsorption cycle. Additionally or alternately, it can generally be preferable to cool the bed before repressurization.
[0042] Regeneration of the bed can additionally or alternately be accomplished through the use of a temperature swing process, or a combination of a temperature swing and pressure swing processes. In the temperature swing process, the temperature of the adsorbent bed can be raised to a point wherein the contaminant gas component(s) can be desorbed from the bed. Purge gases, as described herein, can be utilized during and/or in conjunction with temperature-driven desorption. With the temperature swing desorption, it can additionally or alternately be preferred for the adsorbent bed to be cooled prior to desorption and prior to beginning the next adsorption cycle.
[0043] In a preferred embodiment of the present invention, the contactor is combined with an adsorbent into a heat exchange structure in a manner that can produce a thermal wave. In Thermal Wave Adsorption (TWA), adsorbent can be placed in one set of heat exchanger channels, while the other set of channels can be used to bring heat into and/or take heat out of the adsorbent device. Fluids and/or gases flowing in the adsorbent and heating/cooling channels do not generally contact each other. In certain embodiments, the heat adding/removing channels can be designed and operated in a manner that results in a relatively sharp temperature wave in the adsorbent and/or in the heating and cooling fluids during the heating and cooling steps in the cycle.
[0044] Thermal waves in such contactors can be produced in when the heating and cooling fluids are flowed co-current or counter-current to the direction of the feed flow in the adsorption step. In many cases, it can be preferred not to have a significant flow of heating or cooling fluids during the adsorption step. A more comprehensive description of Thermal Wave Adsorption (TWA) and other appropriate contactor structures can be found, e.g., in U.S. Pat. No. 7,938,886, which is incorporated herein by reference. This reference shows how to design and operate a contactor to control the sharpness and nature of a thermal wave. A key operational parameter can include the fluid velocity in the contactor. Key design parameters can include the mass of the contactor and heat capacity and thermal conductivity of materials used to form the contactor and heat transfer fluid. An additional key design objective for the contactor can be finding one or more ways to reduce/minimize the distance over which heat has to be transferred, which is why relatively sharp thermal waves can be so desirable.
[0045] In some embodiments, during the heating step, the volume of fluid at a temperature no more than 10° C. warmer than the end of the contactor from which it is produced can represent at least 25% (e.g., at least 50% or at least 75%) of the volume of the fluid introduced into the contactor for heating. Similarly, when the present invention is operated to attain a thermal wave, it can be preferred that, during the cooling step, a cold fluid (such as pressurized water) can be flowed into the contactor and a hot fluid near the temperature of the contactor at the end of the recovery step can flow out of the contactor. Most of the recovery step can generally occur after the contactor has been heated. Thus additionally or alternately, during the cooling step, the volume of fluid at a temperature no more than 10° C. colder than the end of the contactor from which it is produced can represent at least 25% (e.g., at least 50% or at least 75%) of the volume of the fluid introduced into the contactor for cooling.
[0046] One way to efficiently utilize thermal waves in the apparatuses according to the invention can be for heat recovery. The recovered energy can be used to reduce the energy requirements for heating and cooling of the contactor, for a different contactor of a multitude of contactors needed for a continuous process, and/or for any other purpose. More specifically, energy contained in the hot stream exiting the contactor during the cooling step can be utilized to reduce the energy that must be supplied during the heating step. Similarly, the cold stream exiting the contactor during the heating step can be utilized to reduce the energy that must be supplied to cool fluid to be supplied to the contactor during the cooling step. There are many ways to recoup the energy. For example, the hot thermal fluid flowing out of one contactor can be sent to another with trim heating in between, and/or the cold fluid flowing out of one contactor can be sent to another with trim cooling in between. The thermal fluid flow path between contactors can be determined by valves timed to route thermal fluid between contactors at appropriate points in the overall swing adsorption cycle. In embodiments where thermal fluid flows between contactors, it may also pass through a heat exchanger that adds or removes heat from the flowing thermal fluid and/or pass through a device, such as a compressor, pump, and/or blower, that pressurizes it so it can flow at the desired rate though the contactors. A heat storage medium can be configured so that the energy from the thermal wave moving through one contactor can be stored. A non-limiting example is a tank system that separately stores hot and cold fluids, which can each be fed back into the contactor that produced it and/or to another contactor. In many embodiments, the flow of the thermal fluid through the contactor can be arranged to minimize the mixing of the fluid in the direction of the general flow of the fluid through the contactor and to minimize the effect of the thermal conductivity of the fluid on the sharpness of the temperature wave.
[0047] Where energy is recovered, it can be preferred that the recovered energy be used to reduce the amount of sensible heat that must be supplied to heat and cool the contactor. The sensible heat is determined by the heat capacity and temperature rise (or fall) of the contactor. In some embodiments, at least 60% (e.g., at least 80% or at least 95%) of the sensible heat required for heating the contactor is recouped, and/or at least 60% (e.g., at least 80% or at least 95%) of the sensible heat needed to cool the contactor is recouped.
[0048] Relatively sharp thermal waves, as used herein, can be expressed in terms of a standard temperature differential over a distance relative to the length of the mass/heat transfer flow in the apparatus. With respect to the mass/heat transfer, we can define a maximum temperature, T max , and a minimum temperature, T min , as well as convenient temperatures about 10% above T min (T 10 ) and about 10% below T max (T 90 ). Thermal waves can be said to be relatively sharp when at least the temperature differential of (T 90 −T 10 ) occurs over at most 50% (e.g., at most 40%, at most 30%, or at most 25%) of the length of the apparatus that participates in the mass/thermal transfer. Additionally or alternately, relative sharp thermal waves can be expressed in terms of a maximum Peclet number, Pe, defined to compare axial velocity of the heating/cooling fluid to diffusive thermal transport roughly perpendicular to the direction of fluid flow. Pe can be defined as (U*L)/α, where U represents the velocity of the heating/cooling fluid (in m/s), L represents a characteristic distance over which heat is transported (to warm/cool the adsorbent) in a direction roughly perpendicular to the fluid flow, and a represents the effective thermal diffusivity of the contactor (in m 2 /s) over the distance L. In addition or alternately to the thermal differential over length, thermal waves can be said to be relatively sharp when Pe is less than 10, for example less than 1 or less than 0.1. To minimize time for heating/cooling of the contactor with little or no damage to the flow channel, it can be preferred for U to be in a range from about 0.01 m/s to about 100 m/s, e.g., from about 0.1 m/s to about 50 m/s or from about 1 m/s to about 40 m/s. Additionally or alternately, to minimize size and energy requirements, it can be preferred for L to be less than 0.1 meter, e.g., less than 0.01 meter or less than 0.001 meter.
[0049] In certain embodiments, the adsorbent bed can cooled, preferably to a temperature equal to or less than about 40° C. above the temperature of feed gas mixture, e.g., less than 20° C. above or less than 10° C. above. Additionally or alternately, the adsorbent bed can be cooled by external cooling that can be done in a co-current or counter-current manner, such that a thermal wave can pass through the bed. Further additionally or alternately, only the first part of the adsorbent bed can be cooled then repressurized. It is within the scope of this invention that the adsorbent bed be purged with a clean gas during this cooling step. The adsorbent bed is then repressurized either during or after the cooling step. The adsorbent bed can be repressurized by use of clean gas, e.g., a clean product gas, and/or counter-currently with blow-down gas from another bed after a first stage of repressurization. The final pressure of the repressurization step can preferably be substantially equal to the pressure of the incoming feed gas mixture.
[0050] Adsorptive kinetic separation processes, apparatuses, and systems, as described above, are useful for development and production of hydrocarbons, such as gas and oil processing. Particularly, the provided processes, apparatuses, and systems can be useful for the rapid, large scale, efficient separation of a variety of target gases from gas mixtures.
[0051] The provided processes, apparatuses, and systems may be used to prepare natural gas products by removing contaminants. The provided processes, apparatuses, and systems can be useful for preparing gaseous feed streams for use in utilities, including separation applications such as dew point control, sweetening/detoxification, corrosion protection/control, dehydration, heating value, conditioning, and purification. Examples of utilities that utilize one or more separation applications can include generation of fuel gas, seal gas, non-potable water, blanket gas, instrument and control gas, refrigerant, inert gas, and hydrocarbon recovery. Exemplary “not to exceed” product (or “target”) acid gas removal specifications can include: (a) 2 vol % CO 2 , 4 ppm H 2 S; (b) 50 ppm CO 2 , 4 ppm H 2 S; or (c) 1.5 vol % CO 2 , 2 ppm H 2 S.
[0052] The provided processes, apparatuses, and systems may be used to remove acid gas from hydrocarbon streams. Acid gas removal technology becomes increasingly important as remaining gas reserves exhibit higher concentrations of acid (sour) gas resources. Hydrocarbon feed streams can vary widely in amount of acid gas, such as from several parts per million to 90 vol %. Non-limiting examples of acid gas concentrations from exemplary gas reserves can include concentrations of at least: (a) 1 vol % H 2 S, 5 vol % CO 2 ; (b) 1 vol % H 2 S, 15 vol % CO 2 ; (c) 1 vol % H 2 S, 60 vol % CO 2 ; (d) 15 vol % H 2 S, 15 vol % CO 2 ; or (e) 15 vol % H 2 S, 30 vol % CO 2 .
[0053] One or more of the following may be utilized with the processes, apparatuses, and systems provided herein, to prepare a desirable product stream, while maintaining relatively high hydrocarbon recovery:
[0054] (a) using one or more kinetic swing adsorption processes, such as pressure swing adsorption (PSA), thermal swing adsorption (TSA), and partial pressure swing or displacement purge adsorption (PPSA), including combinations of these processes; each swing adsorption process may be utilized with rapid cycles, such as using one or more rapid cycle pressure swing adsorption (RC-PDS) units, with one or more rapid cycle temperature swing adsorption (RC-TSA) units or with one or more rapid cycle partial pressure swing adsorption (RC-PPSA) units; exemplary kinetic swing adsorption processes are described in U.S. Patent Application Publication Nos. 2008/0282892, 2008/0282887, 2008/0282886, 2008/0282885, and 2008/0282884, which are each herein incorporated by reference in its entirety;
[0055] (b) removing acid gas with RC-TSA using advanced cycles and purges as described in U.S. Provisional Application No. 61/447,858, filed Mar. 1, 2011, as well as the U.S. Patent Application bearing docket number 2011EM060-US2, claiming priority thereto, which are together incorporated by reference herein in their entirety;
[0056] (c) using a mesopore filler to reduce the amount of trapped methane in the adsorbent and increase the overall hydrocarbon recovery, as described in U.S. Patent Application Publication Nos. 2008/0282892, 2008/0282885, and 2008/028286, each of which is herein incorporated by reference in its entirety;
[0057] (d) choosing an appropriate adsorbent materials to provide high selectivity and reduce/minimize adsorption (and losses) of methane and other hydrocarbons, such as one or more of the zeolites described in U.S. Patent Application Publication Nos. 2008/0282887 and 2009/0211441, each of which is herein incorporated by reference in its entirety;
[0058] (e) depressurizing one or more RC-TSA units in multiple steps to intermediate pressures so that the acid gas exhaust can be captured at a higher average pressure, thereby decreasing the compression required for acid gas injection; pressure levels for the intermediate depressurization steps may be matched to the interstage pressures of the acid gas compressor to optimize the overall compression system;
[0059] (f) using exhaust or recycle streams to minimize processing and hydrocarbon losses, such as using exhaust streams from one or more RC-TSA units as fuel gas instead of re-injecting or venting;
[0060] (g) using multiple adsorbent materials in a single bed to remove trace amounts of first contaminants, such as H 2 S, before removal of a second contaminant, such as CO 2 ; such segmented beds may provide rigorous acid gas removal down to ppm levels with RC-TSA units with minimal purge flow rates;
[0061] (h) using feed compression before one or more RC-TSA units to achieve a desired product purity;
[0062] (j) contemporaneous removal of non-acid gas contaminants such as mercaptans, COS, and BTEX; selection processes and materials to accomplish the same;
[0063] (k) using structured adsorbents for gas-solid contactors to minimize pressure drop compared to conventional packed beds;
[0064] (l) selecting a cycle time and cycle steps based on adsorbent material kinetics; and
[0065] (m) using a process and apparatus that uses, among other equipment, two RC-TSA units in series, wherein the first RC-TSA unit cleans a feed stream down to a desired product purity and the second RC-TSA unit cleans the exhaust from the first unit to capture methane and maintain high hydrocarbon recovery; use of this series design may reduce the need for a mesopore filler.
[0066] The processes, apparatuses, and systems provided herein can be useful in large gas treating facilities, such as facilities that process more than five million standard cubic feet per day (MSCFD) of natural gas, for example more than 15 MSCFD, more than 25 MSCFD, more than 50 MSCFD, more than 100 MSCFD, more than 500 MSCFD, more than one billion standard cubic feet per day (BSCFD), or more than two BSCFD.
[0067] Compared to conventional technology, the provided processes, apparatuses, and systems can require lower capital investment, lower operating cost, and/or less physical space, thereby enabling implementation offshore and in remote locations, such as arctic environments. The provided processes, apparatuses, and systems can provide the foregoing benefits, while providing high hydrocarbon recovery as compared to conventional technology.
[0068] Additionally or alternately, the invention can comprise one or more of the following embodiments.
[0069] Embodiment 1. A swing adsorption process for separating contaminant gas components from a feed gas mixture containing at least one contaminant gas component, which process comprises: a) conducting the feed gas mixture directly to a first adsorption bed in a swing adsorption process unit containing a plurality of adsorbent beds each having a fluid inlet end and fluid outlet end wherein the first adsorption bed has a first primary adsorption cycle defined by the period of time from the start of connecting the fluid input end of the first adsorption bed directly to said feed gas mixture to the end of connecting the fluid input end of the first adsorption bed directly to said feed gas mixture; b) retrieving a first product stream flow from the fluid outlet end of the first adsorption bed; c) fluidly connecting the fluid outlet end of the first adsorption bed with the fluid inlet end of a second adsorption bed in the swing adsorption process unit during a point in the first primary adsorption cycle so that at least a portion of the first product stream from the fluid outlet end of the first adsorption bed is passed to the fluid inlet end of the second adsorption bed at which time the second adsorption bed is in a first secondary adsorption cycle which first secondary adsorption cycle is defined by the period of time from the start of exposing the second adsorption bed to the first product stream from the fluid outlet end of the first adsorption bed to the end of exposing the second adsorption bed to the first product stream from the fluid outlet end of the first adsorption bed; d) retrieving a second product stream flow from the fluid outlet end of the second adsorption bed; e) fluidly disconnecting the fluid outlet end of the first adsorption bed with the fluid inlet end of a second adsorption bed; and f) conducting the feed gas mixture directly to the second adsorption bed wherein the first adsorption bed has a second primary adsorption cycle defined by the period of time from the start of connecting the fluid input end of the second adsorption bed directly to said feed gas mixture to the end of connecting the fluid input end of the second adsorption bed directly to said feed gas mixture, wherein the first product stream and the second product stream each have a lower mol % of the contaminant gas component than the feed gas mixture, and the beginnings and ends of the first primary adsorption cycle and the second primary adsorption cycle do not both coincide with each other.
[0070] Embodiment 2. The process of embodiment 1, wherein one or more of the following is satisfied: step f) starts simultaneously with or prior to the beginning of step e); step c) starts prior to breakthrough of the contaminant gas component from the first adsorption bed; and step e) starts prior to breakthrough of the contaminant gas component from the second adsorption bed.
[0071] Embodiment 3. The process of embodiment 1 or embodiment 2, wherein the adsorption front moves from the first adsorption bed to the second adsorption bed during the first secondary adsorption cycle or during an overlap of the first primary adsorption cycle and the first secondary adsorption cycle.
[0072] Embodiment 4. The process of any one of the previous embodiments, wherein the contaminant gas component is selected from CO 2 , H 2 S, and combinations thereof, e.g., comprises CO 2 , and/or wherein the feed gas mixture is comprised of methane.
[0073] Embodiment 5. The process of any one of the previous embodiments, wherein the first adsorbent bed and the second adsorbent bed are comprised of an B-ring zeolite, e.g., having a Si/Al ratio greater than about 500.
[0074] Embodiment 6. The process of any one of the previous embodiments, wherein feed gas mixture is comprised of methane and CO 2 , wherein CO 2 is the contaminant gas component, and the zeolite has a diffusion coefficient for CO 2 over methane (D CO2 /D CH4 ) greater than 10.
[0075] Embodiment 7. The process of any one of the previous embodiments, wherein feed gas mixture is comprised of methane and N 2 , wherein N 2 is the contaminant gas component, and the zeolite has a diffusion coefficient for N 2 over methane (D N2 /D CH4 ) greater than 10.
[0076] Embodiment 8. The process of any one of the previous embodiments, wherein feed gas mixture is comprised of methane and H 2 S, wherein H 2 S is the contaminant gas component, and the zeolite has a diffusion coefficient for H 2 S over methane (D H2S /D CH4 ) greater than 10.
[0077] Embodiment 9. The process of any one of the previous embodiments, wherein the first adsorbent bed and the second adsorbent bed are comprised of a zeolite selected from DDR, Sigma-1, ZSM-58, and combinations and intergrowths thereof.
[0078] Embodiment 10. The process of any one of the previous embodiments, wherein the first adsorbent bed and the second adsorbent bed are comprised of a microporous material selected from zeolites, AlPOs, SAPOs, MOFs (metal organic frameworks), ZIFs, carbon, and combinations and intergrowths thereof.
[0079] Embodiment 11. The process of any one of the previous embodiments, wherein the first adsorbent bed and the second adsorbent bed are comprised of a material selected from cationic zeolites, amine-functionalized mesoporous materials, stannosilicates, carbon, and combinations thereof.
[0080] Embodiment 12. The process of any one of the previous embodiments, wherein the first adsorbent bed and the second adsorbent bed are comprised of a zeolite selected from MFI, faujasite, MCM-41, Beta, and combinations and intergrowths thereof.
[0081] Embodiment 13. The process of any one of the previous embodiments, wherein the process is a rapid cycle pressure swing adsorption process wherein a total cycle time is less than 200 seconds, e.g., less than 30 seconds.
[0082] Embodiment 14. The process of any one of the previous embodiments, wherein one or more of the following is satisfied: the feed gas mixture is conducted to the first adsorption bed at a pressure greater than 1,000 psig; the first adsorbent bed is cooled to a temperature no more than about 40° C. above the temperature of feed gas mixture prior to step a); and at least one adsorbent bed in the swing adsorption process is a parallel channel contactor.
EXAMPLES
Example 1
[0083] This Example demonstrates that there a stable solution can be formed when the adsorption front is rolled from one bed into another and that it is possible to achieve excellent performance in a swing adsorption process. A detailed model was constructed using gPROMS differential equation solving software of a PSA cycle in which the adsorption front was rolled from one bed into another. The model includes all of the important mass transport effects known to those skilled in the art, such as competitive adsorption, kinetics of molecular transport into the adsorbent, thermal effects due to the heat of adsorption, and thermodynamics (non-ideality and fugacity) of the gas mixture throughout the contactor, for example. The model also accounted for the important hydrodynamic effects known to those skilled in the art such as gas velocity in the contactors, pressure drop through the contactors, and pressure drops across valves, inter alia. The model was configured to describe parallel channel contactors in the form of monoliths housed in pressure vessels with poppet valves to control flow of gases in a 12-step PSA process. Open gas channels in the monolith were square passages ˜200 micron high and ˜200 microns wide. A ˜100 micron thick adsorbent layer containing ˜60 vol % relatively uniform-sized DDR zeolite crystals lined the gas passages and a ˜100 micron thick web surrounded the adsorbent layer. With this structure, the distance between centers of adjacent gas passages was ˜500 microns. Each monolith modeled was ˜0.915 meters long and ˜1 meter in diameter. A portion of the mesopores (˜99%) in the adsorbent layer was filled with a mesopore filler (see, e.g., U.S. Pat. No. 7,959,720, which is incorporated herein by reference). The size of the DDR crystals was chosen so the LDF (linear driving force) time constant for CO 2 diffusion into the crystals was ˜10 sec −1 at the ˜55° C. temperature of the feed. The fresh feed stream entered the process with a pressure of ˜55 bara and had a molar composition of ˜30% CO 2 and ˜70% CH 4 .
[0084] FIG. 7 shows the pressure profile of one of 14 monoliths (beds) interconnected with valving to form a skid using. All monoliths on the skid were modeled to have a similarly shaped pressure profile that may be offset in time. The PSA cycle shown was designed with bed to bed equalizations. Gases withdrawn from the monolith adsorbent bed during the depressurization step were used to re-pressurize another bed on the skid. After the adsorption step has been completed and the adsorption front has been rolled into another bed and the CO 2 adsorption front has moved entirely through the monolith, the monolith was modeled to undergo a first depressurization/equalization step [ 102 ] (referred to as EQ # 1 ). In this step, a valve on the housing for the monolith opened and connected the bed to another bed being repressurized. Gas flowed from the bed being depressurized to the bed being repressurized, and the valve was held open long enough so that the pressures between the two beds could equalize. After equalization the bed underwent a second depressurization/equalization step [ 104 ] (referred to as EQ # 2 ). In this step, another valve on the housing for the monolith opened and connected the bed to a bed beginning to be repressurized. Gas flowed from the bed being depressurized to the bed being repressurized, and the valve was held open long enough so that the pressures between the two beds could equalize. After the beds equalized, the valve closed and the bed underwent a purge step [ 106 ].
[0085] As shown in FIG. 8 , in this step, a CO 2 -rich stream that has been collected [ 202 ] from the exhaust [ 204 , 206 , 208 ] of later blowdown CO 2 recovery steps was used to purge methane out of the bed. The purge stream [ 210 ] fed into the bed is referred to as the CO 2 Purge Inlet, and the purge stream coming out of the bed [ 212 ] is referred to as the CO 2 Purge Outlet. The CO 2 Purge Outlet was compressed and blended [ 214 ] with the incoming feed stream [ 216 ]. After the methane was purged from the bed, the bed was depressurized in a series of three blowdown recovery steps [ 108 , 110 , 112 ]. Gas collected was used to form streams 204, 206, 208 (referred to as BD 1 exhaust, BD 2 exhaust, and BD 3 exhaust, respectively). At the end of blowdown # 3 , the bed was depressured to 1.4 bara. At this point, the bed was valved to begin a repressurization step [ 114 ] (referred to as R # 2 ). In this step, the bed was connected to another bed undergoing step EQ # 2 . Gas coming from the EQ # 2 step in the other bed was used to increase the bed pressure in step R # 2 . Once the beds have equalized, the bed was valved to begin another repressurization step [ 116 ] (referred to as R # 1 ). In this step, the bed was connected to another bed undergoing step EQ # 1 . Gas coming from the EQ # 1 step in the other bed was used to increase the bed pressure in step R # 1 . Once the beds equalized, the bed was valved to begin a final repressurization step [ 118 ] (referred to as Product RP). In this step, a slip stream [ 218 ] from the purified product
[0086] was used to repressurize the bed.
[0087] Once the product repressurization was completed, the bed began accepting the effluent from the adsorption step occurring in another bed to produce product [ 220 ]. In this step, the CO 2 adsorption front from another bed passed into the bed. The model showed that the adsorption front remained relatively sharp as it is rolled through the beds. After the adsorption front rolled into the bed, the bed was valved [ 122 ] to accept feed blended with the CO 2 purge effluent recycle [ 222 ]. During this step [ 122 ], the bed was connected to another bed initiating the adsorption process. In this step [ 122 ], the CO 2 adsorption front rolled through the bed and into the bed in the initial phase of the adsorption process. The model showed that, as the CO 2 adsorption front moved through the bed, it remained relatively sharp.
[0088] The model (which assumed a kinetic selectivity of about 500) indicated that a 14-bed skid was theoretically capable of processing ˜81.8 million SCFD and of recovering ˜94% the methane fed, while producing a product methane purity of ˜95 mol % in a process that did not require vacuum or a rerun PSA. Approximately 9% of the methane fed was internally recycled in the process. Detailed stream compositions, pressures, temperatures, and flow rates are summarized in the table below.
[0000]
Flowrate per
Molar Flow
Molar Flow
Flowrate For
Monolith
CO2
CH4
Pressure
Temp
Mol %
Mol %
14 Bed Skid
Stream
(MSCFD)
(mol/cycle)
(mol/cycle)
(bar)
(deg C.)
CO2
CH4
(MSCFD)
Feed and
6.4
369
782
55.0
55.0
32.1
67.9
89.9
Recycle
CO2 Purge
0.78
120
19.5
15.7
55.0
86.0
14.0
10.9
Inlet
Product RP
0.75
1.35
134
55.0
55.0
1.0
99.0
10.5
Product
5.1
37.9
871
53.0
22.7
4.2
95.8
71.0
CO2 Purge
0.58
56.8
46.5
14.7
23.9
55.0
45.0
8.06
Outlet
BD1
0.58
88.1
16.0
9.12
22.0
84.7
15.3
8.13
Blowdown
BD2
1.1
171
18.5
3.25
22.0
90.2
9.8
14.8
Blowdown
BD3
0.96
140
31.6
1.4
22.0
81.6
18.4
13.4
Blowdown
EQ #1
0.76
46.5
90.6
32.4
27.1
33.9
66.1
10.7
EQ #2
0.75
60.7
74.0
15.7
26.4
45.1
54.9
10.5
R #1
0.80
48.8
95.3
32.4
27.1
33.9
66.1
11.3
R #2
0.84
68.5
81.9
15.7
26.4
45.5
54.5
11.8
Product Gas
4.3
36.6
737
53.0
22.7
04.7
95.3
60.4
Fresh Feed
5.8
312
736
55.0
55.0
29.8
70.2
81.8
Gas
Recycle
0.58
56.8
46.5
55.0
23.9
55.0
45.0
8.06
Exhaust
1.8
279
46.5
9.12
22
85.7
14.3
25.4 | A process for reducing the loss of valuable products by improving the overall recovery of a contaminant gas component in swing adsorption processes. The present invention utilizes at least two adsorption beds, in series, with separately controlled cycles to control the adsorption front and optionally to maximize the overall capacity of a swing adsorption process and to improve overall recovery a contaminant gas component from a feed gas mixture. |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation in part application of U.S. patent application Ser. No. 12/096,306, filed Oct. 15, 2008, entitled “Method for Synthesizing Ultrahigh-Purity Silicon Carbide”, which is the national stage of International Application No. PCT/US2006/046673, filed Dec. 7, 2006, which claims the benefit of U.S. Provisional Application No. 60/748,347, filed Dec. 7, 2005, all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to synthesis of ultrahigh-purity (UHP) polycrystalline silicon carbide (SiC) for the use as a vapor source in industrial-scale growth of high quality SiC single crystals by sublimation.
[0004] 2. Description of Related Art
[0005] Hexagonal 4H and 6H polytypes of silicon carbide possess unique combinations of electronic and thermo-physical properties, which enable operation of semiconductor devices at significantly higher power, frequency and temperature than comparable devices made from conventional silicon. Semi-insulating (SI) 4H SiC and 6H SiC wafers serve as lattice-matched substrates in GaN-based high-electron-mobility transistors (HEMT) operational at microwave frequencies and high power levels. To provide for optimum device performance, the SiC substrate must have the correct resistivity. For microwave devices, the SiC substrate must be semi-insulating with the resistivity on the order of 10 10 -10 11 Ohm-cm. In order to achieve this resistivity, the presence of unwanted residual impurities in the crystal must be minimized.
[0006] Commercial-size SiC single crystals are grown by the sublimation technique called Physical Vapor Transport (PVT). In PVT growth, a graphite crucible, typically a cylindrical graphite crucible, is loaded with polycrystalline SiC source material (typically SiC grain) at the bottom, while a SiC single crystal seed wafer (or segment thereof) is disposed at the crucible top, for instance, attached to the crucible lid. The loaded crucible is placed in a gas-tight furnace chamber and, in the presence of an inert atmosphere, is heated to the temperature of SiC sublimation growth, typically, between 2000° C. and 2400° C., with the temperature of the polycrystalline SiC source material being higher by 10-100° C. than the temperature of the SiC single crystal seed. Under these conditions, the SiC source material sublimes and the sublimation vapors migrate, under the influence of temperature difference between the SiC source grain and the SiC single crystal seed, to the SiC single crystal seed where the vapors condense on the SiC single crystal seed causing growth of a SiC single crystal on said SiC single crystal seed. In order to control the growth rate and ensure high crystal quality, PVT growth is carried out under a small pressure of inert gas, generally, between 1 Torr and 100 Torr.
[0007] Availability of high-purity SiC source material is important for the growth of SiC single crystals in general, and it is crucial for semi-insulating SiC crystals. In addition to high purity, the SiC source material must be of proper polytype and grain size. For the growth of 6H and 4H SiC single crystals, the desired SiC source material is of “alpha” polytype, that is with crystallites belonging to SiC hexagonal polytypes, such as 4H and/or 6H.
[0008] Prior art SiC synthesis includes four basic methods. The methods are:
The Acheson Process
[0009] The most widely used large-scale commercial process for production of technical grade SiC is disclosed in U.S. Pat. Nos. 492,767 and 615,648. In this process, a mixture of quartz sand (SiO 2 ) and coke (C) containing various additives is heated up to 3000° C. to form a mass of SiC crystals according to the reaction: SiO 2 +3C SiC+2CO. While numerous modifications of the Acheson process have been developed over the years, the produced SiC material always contains high concentrations of boron, nitrogen, aluminum and other metals, and is unsuitable as a source material for the growth of semiconductor-quality SiC crystals.
Chemical Vapor Deposition (CVD)
[0010] Bulk SiC shapes with a density close to a theoretical SiC density (3.2 g/cm 3 ) are produced commercially by CVD (see for instance U.S. Pat. No. 5,704,985). In this process, silicon and carbon-containing gaseous precursors react at elevated temperatures, typically, 1200° C. to 1400° C., to form solid SiC. Commonly, SiC is deposited on a suitable substrate such as graphite. A single precursor containing both Si and C atoms, such as Trimethylsilane, can be used as well. Although high-purity precursors are available, commercial-grade bulk SiC produced by CVD is not pure enough for the use as a source in SiC crystal growth, especially for semi-insulating SiC crystals, as such commercial-grade bulk SiC usually contains boron (0.7-2 ppm), metal impurities and nitrogen (up to 100 ppm). In addition, the CVD process yields cubic “beta” polytype of SiC, which is undesirable for crystal growth of 4H and 6H SiC polytypes.
Reactions between Liquid or Solid Silicon and Carbon Compounds
[0011] U.S. Pat. No. 5,863,325 is an example of this approach to SiC synthesis, wherein organic alkoxysilanes and inorganic SiO 2 were used as a Si source, while phenolic resin was used as a C source. This type of reaction requires catalysts and other additives, which are undesirable from the standpoint of purity. The produced SiC material contains large concentrations of contaminants and is unsuitable for the growth of semiconductor-quality SiC crystals.
Direct Synthesis of SiC from Elemental Silicon and Carbon
[0012] SiC can be formed by direct reaction between its elemental components: C+Si SiC. Elemental silicon and elemental carbon are commercially available in high-purity form. One method of direct synthesis of high purity polycrystalline SiC from elemental Si and C is disclosed in US Patent Application Publication No. 2009/0220788, which is incorporated herein by reference.
[0013] US Patent Application Publication No. 2012/0114545 (hereafter “the '545 publication”) discloses a two-stage SiC synthesis process wherein, in preparation for synthesis, a mixture of elemental silicon and elemental carbon (i.e., the Si+C charge) is disposed at the bottom of a graphite crucible, while a free space is provided between the Si+C charge at the bottom and the crucible lid situated at the crucible top. The loaded crucible is placed inside a gas-tight furnace chamber which is evacuated and then backfilled with pure inert gas to a pressure of 300 to 600 Torr. In a first stage of the process, the Si+C mixture is heated to a temperature of 1600° C. or higher to react and synthesize the initial SiC charge.
[0014] In a second stage of the process, the chamber pressure is reduced to be between 0.05 and 50 Torr, and the system is soaked for 24 to 100 hours. In these conditions, the initial SiC charge sublimes, the vapors condense on the crucible lid thus forming a dense polycrystalline SiC body. The polytype of this SiC body can be controlled by attaching a SiC seed wafer (or segment thereof) of a desired polytype to the crucible lid.
[0015] The '545 publication discloses high purity of the final polycrystalline SiC product with respect to P, B, Al, Ti, V and Fe. However, it provides no data on nitrogen content. Attempts at reproducing the process disclosed in the '545 publication yielded polycrystalline SiC containing nitrogen at levels above 1·10 16 cm −3 and as high as 3·10 17 cm −3 . This high nitrogen content precludes the use of such material as a source in growth of semi-insulating SiC crystals.
SUMMARY OF THE INVENTION
[0016] Disclosed herein is a method of producing Ultra High Purity (UHP) polycrystalline silicon carbide having low levels of residual impurities, including nitrogen at levels ≦8×10 15 atoms/cm −3 . The method yields bulk polycrystalline grain having SiC particles with diameters in the range between 0.2 and 2 mm, said particles belonging to hexagonal SiC polytypes.
[0017] Synthesis of SiC is desirably carried out in a graphite crucible, which is loaded with a reactive mixture of elemental C and elemental Si, and a high purity, light-weight bulk carbon, which is gas- and vapor-permeable (hereinafter “carbon barrier”). The starting elemental Si and elemental C are of high purity, with the purity grade of silicon between 99.99999% and 99.9999999% of Si, and the purity grade of carbon equal to or better than 99.9999% of C. The carbon barrier has a purity equal to or better than 99.9999% of C. Prior to synthesis, all graphite parts of the furnace are halogen-purified, desirably to 20 weight ppm of ash and, more desirably, to 5 weight ppm of ash. The graphite crucible is purified, desirably, to 5 weight ppm of ash and, more desirably, to 1 ppm of ash. Prior to synthesis, residual nitrogen is removed from the growth ambient.
[0018] Next, a two-stage SiC synthesis process is performed in the graphite crucible, which is loaded with a reactive mixture of elemental C and elemental Si, and the carbon barrier. In the first stage of the process, direct reaction between the elemental Si and the elemental C of the reactive mixture in the crucible takes place leading to the formation of an as-synthesized SiC charge that includes primarily cubic 3C polytype of SiC, said SiC charge includes traces of residual impurities, including nitrogen. In the second stage of the process, the as-synthesized SiC charge produced in the first stage is purified and converted into high-purity, bulk SiC grain of hexagonal polytype and desired particle size.
[0019] The second stage is carried out at temperatures between 2200 and 2400° C., where the cubic 3C polytype of SiC is thermodynamically unstable, while the hexagonal SiC polytypes are stable. The second stage comprises sublimation of the as-synthesized SiC charge and vapor transport across the carbon barrier. During such vapor transport, numerous and repeatable cycles of condensation, reaction and sublimation in the bulk of the carbon barrier take place. Each such cycle includes the following steps: (i) condensation of sublimated SiC vapor on the carbon barrier leading to the formation of SiC deposits on said carbon barrier; (ii) enrichment of the vapor in the crucible with silicon; (iii) reaction between the Si-rich vapor and the carbon of the carbon barrier resulting in the formation of additional solid SiC on the carbon barrier; and (iv) re-sublimation of the SiC deposits formed on the carbon barrier. The net result of the steps (i)-(iv) is nucleation and growth of hexagonal SiC crystallites in the bulk of the carbon barrier combined with deep purification of SiC, including removal of impurities, such as nitrogen.
[0020] The end product of the process is bulk polycrystalline SiC grain material that includes SiC particles belonging to hexagonal polytypes with linear particle sizes (diameters) in the range between 0.2 and 2 mm.
[0021] The purity of the bulk polycrystalline SiC grain material produced in this manner was characterized using the methods of Glow Discharge Mass Spectroscopy (GDMS) and Secondary Ion Mass Spectroscopy (SIMS). SIMS was performed on larger SiC crystallites (˜2 mm in size) recovered from the bulk polycrystalline SiC grain. These larger SiC crystallites included B, Al, Fe and other metal contaminants in concentrations below the detection limit of GDMS, i.e., below 0.01-0.005 weight ppm. SIMS results of these larger SiC crystallites showed the levels of B consistently below 3·10 15 atoms/cm −3 ; Al below 1·10 15 atoms/cm −3 ; Fe and Ti below 1·10 14 atoms/cm −3 . The levels of background nitrogen in these larger SiC crystallites were below 8·10 15 atoms/cm −3 , which is close to SIMS detection limit for N.
[0022] High-purity polycrystalline SiC grain synthesized in the above manner was then used as SiC source material in the growth of vanadium-doped semi-insulating SiC crystals of 6H and 4H polytypes. The grown 6H and 4H polytype crystals exhibited high resistivity—on the order of between 1·10 11 and 5·10 11 Ohm-cm.
[0023] Also disclosed herein is a method of forming polycrystalline SiC material comprising the steps of: (a) positioning a bulk carbon barrier at a first location inside of a graphite crucible, wherein the bulk carbon barrier is gas-permeable and vapor-permeable; (b) positioning a mixture comprised of elemental silicon (Si) and elemental carbon (C) at a second location inside of the graphite crucible; (c) following steps (a) and (b), removing adsorbed gas, or moisture, or volatiles or some combination of adsorbed gas, moisture and volatiles from the mixture and the bulk carbon barrier positioned inside of the graphite crucible by heating the mixture and the bulk carbon barrier positioned inside of the enclosed crucible to a first temperature which is below the melting point of the elemental Si; (d) following step (c), forming as-synthesized silicon carbide (SiC) inside of the crucible by heating the mixture positioned inside of the enclosed crucible to a second temperature sufficient to initiate a reaction between the elemental Si and the elemental C of the mixture that forms the as-synthesized SiC inside of the crucible, wherein during each of steps (c) and (d) a vacuum pump evacuates at least the inside of the enclosed crucible; and (e) following step (d), forming polycrystalline SiC material inside of the bulk carbon barrier by heating the as-synthesized SiC and the bulk carbon barrier in the presence of a temperature gradient sufficient to cause the as-synthesized SiC to sublime and produce vapors that migrate under the influence of the temperature gradient into the bulk carbon barrier where the vapors condense on the bulk carbon barrier and react with the bulk carbon barrier forming the polycrystalline SiC material, wherein a lowest temperature of the temperature gradient is a third temperature.
[0024] The mixture can consist essentially of elemental Si and elemental carbon C.
[0025] Following steps (a) and (b), part of the mixture can contact part of the bulk carbon barrier inside of the graphite crucible.
[0026] The bulk carbon barrier can be at least 99.9999% pure C. The elemental Si can be at least 99.9999% pure Si. The elemental C can be at least 99.9999% pure C. More desirably, the elemental Si can be between 99.99999% and 99.9999999% pure Si and/or the elemental C can be at least 99.99999% pure C.
[0027] The elemental Si can be comprised of lumps or granules of polysilicon, with each lump or granule having a maximum linear dimension of (e.g., diameter) between 1 mm and 7 mm. The elemental C can be a carbon powder.
[0028] The bulk carbon barrier can be carbon black, carbon beads or pelletized carbon black. The bulk carbon barrier can have a density between 0.3-0.5 g/cm 3 .
[0029] Step (e) can be carried out in the presence of either a vacuum (e.g., <10 −4 Torr) or a pressure of inert gas between 1 and 50 Torr. The inert gas can be argon.
[0030] The first temperature is desirably less than the second temperature, and the second temperature is desirably less than the third temperature.
[0031] Step (d) desirably occurs for a period of time sufficient to complete the reaction between the elemental Si and the elemental C.
[0032] Step (e) desirably occurs for a period of time sufficient to complete or substantially complete the sublimation of the as-synthesized SiC and the formation of the polycrystalline SiC material inside of the bulk carbon barrier.
[0033] The mixture of step (b) desirably has a C:Si atomic ratio between 1:1 and 1.2:1.
[0034] The first temperature can be between 1300° C. and 1400° C.; and/or the second temperature can be between 1550° C. and 1800° C.; and/or the third temperature can be between 2200° C. and 2400° C.
[0035] The final polycrystalline SiC product can comprise: a mixture of alpha (hexagonal) SiC polytypes; particle sizes between 0.2 and 2 mm; a concentration of nitrogen <8·10 15 cm −3 ; a concentration of boron <6·10 15 cm −3 ; a concentration of aluminum below 1·10 15 cm −3 ; a concentration of iron below 3·10 14 cm 3 ; and a concentration of titanium below 3·10 14 cm −3 .
[0036] The method can comprise one or more of the following: step (d) immediately follows step (c); the vacuum in step (c) runs between 10 −3 -10 −4 Torr near the beginning of step (c) to between 10 −5 -10 −6 Torr just prior to step (d); step (e) immediately follows step (d); the vacuum in step (d) runs between 10 −2 -10 −3 Torr near the beginning of step (c) to less than 10 −4 Torr just prior to step (e); and the vacuum in step (e) is less than 10 −4 Torr.
[0037] Following steps (a) and (b) and prior to step (c), the method can further include the step of: outgassing the mixture and the bulk carbon barrier positioned inside of the graphite crucible via the vacuum pump evacuating at least the inside of the enclosed crucible at ambient temperature.
[0038] Also disclosed is a polycrystalline SiC material comprising: a mixture of alpha (hexagonal) SiC polytypes; particle sizes between 0.2 and 2 mm; a concentration of nitrogen <8·10 15 cm −3 ; a concentration of boron <6·10 15 cm −3 ; a concentration of aluminum <1·10 15 cm −3 ; a concentration of iron <3·10 14 cm −3 ; and a concentration of titanium < 3 · 10 14 cm −3 .
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a cross-sectional schematic diagram of a cell for two-stage synthesis of high-purity SiC polycrystalline grain material;
[0040] FIGS. 2A-2C are isolated views of the graphite crucible in FIG. 1 at different stages of the two-stage SiC synthesis;
[0041] FIG. 3 illustrates elemental steps of vapor condensation, reaction, and sublimation leading to the formation of SiC polycrystalline grain material and the removal of impurities therefrom;
[0042] FIG. 4A is a cross-section of a time release capsule for use in the growth of vanadium compensated SiC single crystals;
[0043] FIG. 4B is a cross-sectional schematic drawing of a growth crucible with the time release capsule of FIG. 4A buried in SiC polycrystalline grain material made in accordance with the steps of FIG. 3 , a SiC single seed crystal opposite the SiC polycrystalline grain material and showing the PVT growth of an SiC single crystal on the SiC single crystal seed; and
[0044] FIGS. 5A-5C show additional embodiments of crucibles for two-stage synthesis of high-purity SiC polycrystalline grain material.
DETAILED DESCRIPTION OF THE INVENTION
[0045] FIG. 1 is a cross-sectional, schematic view of a cell 2 for two-stage synthesis of SiC polycrystalline grain material in accordance with the present invention. Cell 2 includes a gas-tight furnace chamber 10 housing a graphite crucible 11 surrounded by thermal insulation 12 . A heater 13 is shown schematically as an RF coil, although resistive heating can also or alternatively be used. Windows 14 a and 14 b in thermal insulation serve for monitoring temperature at the crucible top and bottom using an optical pyrometer. The position of crucible 11 with respect to heater 13 is such that at high temperatures of 1900° C. or higher, a temperature gradient is present, with the temperature of the crucible bottom higher than the temperature of the top of the crucible, desirably, by 50 to 100° C.
[0046] Crucible 11 is desirably made from dense, fine-grain, isostatically molded graphite, such as Grade SiC-6, available from Toyo Tanso USA, Inc. of 2575 NW Graham Circle, Troutdale, Oreg. 97060, USA, or similar. The dimensions of crucible 11 , without limitation, can be: 100 to 250 mm in outer diameter, 150 to 300 mm tall, and wall thickness between 8 mm and 20 mm. Thermal insulation 12 is, desirably, made of light-weight, fibrous graphite, such as Mersen grade Calcarb-CBCF available from Mersen USA, 900 Harrison St., Bay City, Mich. 48708.
[0047] Prior to use, both crucible 11 and thermal insulation 12 are halogen-purified to minimize the presence of background contaminants, such as, without limitation boron, phosphorus and metallic impurities, including aluminum. The purification grade of thermal insulation 12 is, desirably, without limitation, 20 weight ppm of ash, and, more desirably, 5 weight ppm of ash. The purification grade of graphite crucible 11 is, desirably, without limitation, 5 weight ppm of ash, and, more desirably, 1 weight ppm of ash.
[0048] Crucible 11 is charged or loaded at the bottom with a reactive mixture 15 consisting substantially of elemental silicon of between 99.99999% and 99.9999999% of Si and elemental carbon of at least 99.9999% of C. The C:Si atomic ratio of mixture 15 is desirably between 1:1 and 1.2:1. That is, compared to a stoichiometric 1:1 composition, the mixture can contain up to 20 atomic % of extra carbon. As used herein, the phrase “consisting substantially of”, when utilized in connection with elemental silicon and elemental carbon, means that each of the elemental silicon and elemental carbon have the purity levels described herein and may include trace amounts of one or more elements other than elemental silicon and elemental carbon.
[0049] The elemental silicon component of mixture 15 is desirably polysilicon in the form of lumps, shot, granules or particles which are desirably 1 to 7 mm in linear dimension or diameter. The carbon component of mixture 15 is desirably in the form of carbon black, carbon beads or pelletized carbon black. In one non-limiting example, the carbon component is Thermax Ultra-Pure® carbon black available from Cancarb Ltd., 1702 Brier Park Crescent N.W. Medicine Hat, Alberta, Canada, T1C 1 T9. Other forms of carbon, such as high-purity graphite powder 5 to 100 micron in diameter, are also acceptable as long as they have the purity described herein.
[0050] In FIG. 1 , a bulk carbon barrier 16 is loaded in crucible 11 on top of the reactive mixture 15 . Desirably, carbon barrier 16 is high-purity carbon black, carbon beads or pelletized carbon black—all having a density between 0.3 and 0.5 g/cm 3 . The space occupied in crucible 11 by carbon barrier 16 is desirably between 25% and 50% of the total volume of crucible 11 . As shown in FIG. 1 , a top surface or part of mixture 15 may contact a bottom surface or part of bulk carbon barrier 16 at an interface 18 .
Initial Outgassing
[0051] In preparation for synthesis of SiC polycrystalline grain material, chamber 10 is loaded with crucible 11 , as shown in FIG. 1 . Chamber 10 is then sealed and evacuated at room or ambient temperature, e.g., 20-27° C., using one or more conventional vacuum pump(s) 4 , such as a roughing pump and/or a turbomolecular pump. Normally, this initial outgassing takes 4 to 8 hours, depending on chamber 10 , the graphite forming thermal insulation 12 and crucible 11 , the volume of mixture 15 , as well as the capacity of vacuum pump(s) 4 . At the end of this outgassing, the residual pressure in chamber 10 reaches, desirably, 10 −5 -10 −6 Torr or lower. Since the graphite forming crucible 11 and thermal insulation 12 is/are highly permeable to atmospheric gases, the vacuum produced in chamber 10 by vacuum pump(s) 4 appears almost immediately in the interior of crucible 11 .
Heated Outgassing
[0052] Immediately following initial outgassing at room temperature and without breaking vacuum on chamber 10 , heater 13 is energized to bring the temperature of crucible 11 to a level, desirably, between 1300 and 1400° C. This temperature must be below the melting point of silicon (1420° C.), otherwise, premature and unwanted reaction between the elemental silicon and the elemental carbon forming mixture 15 may start. This heated outgassing achieves a deeper removal of residual volatiles and gases (air, moisture, organics) from the graphite parts, such as crucible 11 and thermal insulation 12 , as well as from the elemental carbon component of mixture 15 and bulk carbon barrier 16 contained in crucible 11 . At the beginning of heated outgassing, the chamber pressure may increase, due to outgassing of components in chamber 10 , to between 10 −3 -10 −4 Torr, depending on the size of chamber 10 , the amount of graphite in chamber 10 (including the graphite parts, such as crucible 11 and thermal insulation 12 , as well as from the carbon component of mixture 15 and bulk carbon barrier 16 contained in crucible 11 ), the weight of reactive mixture 15 and bulk carbon barrier 16 , the capacity of pump(s) 4 , and the rate of temperature rise. However, within several hours of heated outgassing, the continuous pumping by pump(s) 4 on chamber 10 should return the pressure in chamber 10 to about 10 −5 -10 −6 Torr or lower. At the above temperature (1300-1400° C.) and under continuous pumping by pump(s) 4 , cell 2 is soaked, desirably, for 6 to 24 hours. FIG. 2A illustrates the status of crucible 11 at the end of the heated outgassing step and prior to stage (a) of SiC synthesis described next.
Stage (a) of SiC Synthesis
[0053] Immediately following heated outgassing and without breaking vacuum on chamber 10 , furnace chamber 10 continues to be under continuous pumping by vacuum pump(s) 4 , with the pressure in chamber 10 and, hence, crucible 11 between 10 −5 -10 −6 Torr or lower. Power to heater 13 is controlled to raise the temperature of crucible 11 toward between 2200 and 2400° C. over a period of several hours, desirably, between 4 and 8 hours. As the temperature of crucible 11 passes through between 1550 and 1800° C. on its way to between 2200 and 2400° C., reaction between the elemental silicon and the elemental carbon of reactive mixture 15 starts. The reaction between the elemental silicon and the elemental carbon of reactive mixture 15 is exothermic and the onset of this reaction can be accompanied by an increase in the temperature of crucible 10 and, due to outgassing of components in chamber 10 , by an increase in pressure in chamber 10 . The pressure in chamber 10 can increase to, without limitation, between 10 −2 and 10 −3 Torr.
[0054] The end of the reaction between the elemental Si and the elemental C of mixture 15 is accompanied by a reduction in the chamber 10 pressure, which normally returns back to, without limitation, 10 −4 Torr or below. Based on observations, it takes 2 to 4 hours to conclude the reaction between the elemental Si and the elemental C of mixture 15 , depending on the size of the charge of mixture 15 in crucible 11 . The reaction between the elemental Si and the elemental C of mixture 15 yields a dense mass of as-synthesized polycrystalline SiC (hereinafter “as-synthesized SiC charge”) comprised substantially of “beta” (cubic) SiC crystallites. The status at the end of phase (a) of the process is illustrated in FIG. 2B , where the as-synthesized SiC charge is shown as item 20 .
[0055] The purity of the as-synthesized SiC charge 20 was characterized using the methods of Glow Discharge Mass Spectroscopy (GDMS) and Secondary Ion Mass Spectroscopy (SIMS). The as-synthesized SiC charge 20 was observed to include noticeable traces of residual contaminants, such as B, S, Fe and V, at levels on the order of 0.01-0.1 weight ppm. SIMS analysis was performed on larger SiC crystallites (˜2 mm in size) recovered from as-synthesized SiC charge 20 and showed nitrogen levels as high as 5·10 17 cm −3 .
Stage (b) of SiC Synthesis
[0056] Immediately following stage (a) of SiC synthesis and without breaking vacuum on chamber 10 , the heating of crucible 11 by heater 13 continues until crucible 11 reaches temperatures between 2200 and 2400° C., with the temperature at the bottom of crucible 11 being higher, desirably, by 50 to 100° C. than the temperature at the top of crucible 11 , i.e., an axial temperature gradient exists in crucible 11 . This stage of the process can be carried out either under vacuum, e.g., without limitation, 10 −5 -10 −6 Torr or lower, established by pump(s) 4 or under a small pressure of pure inert gas, e.g., without limitation, between 1 and 50 Torr. In the case of carrying out SiC synthesis under a vacuum, pumping of the chamber 10 by pump(s) 4 continues. In the case of carrying out SiC synthesis under a small pressure of inert gas, inert gas 8 , such as argon, is introduced into the furnace chamber 10 from an attached inert gas source (item 6 in FIG. 1 ) to generate a pressure, desirably, between 1 and 50 Torr in chamber 10 and in crucible 11 . The purity of the inert gas 8 with respect to nitrogen is, desirably, 10 ppb or better.
[0057] As the temperature of crucible 11 reaches and exceeds 1900° C., substantial sublimation of the as-synthesized SiC charge 20 starts. Driven by the axial temperature gradient, i.e., the temperature gradient between the bottom and the top of crucible 11 , the sublimation vapors migrate upward towards the top of crucible 11 , as symbolized by arrow 21 in FIG. 2C and permeate into the low-density, gas- and vapor-permeable carbon barrier 16 , shown best in FIGS. 2A-2B . The net result of such vapor migration is the formation of high-purity, polycrystalline hexagonal SiC grain in the bulk of the carbon barrier 16 . The hexagonal SiC grain formed in the bulk of carbon barrier 16 is symbolized by reference no. 23 in FIG. 2C .
[0058] While not wishing to be bound by any particular theory, the following paragraphs elucidate the observed phenomena and mechanism of purification.
[0059] It is known in the art of SiC sublimation growth that SiC sublimes incongruently with the Si:C atomic ratio in the vapor phase being substantially higher than 1:1; for instance, as high as 1.5:1. Therefore, upon sublimation of the as-synthesized SiC charge, carbon residue in the form of aggregated graphene sheets is left behind (this carbon residue is shown as item 22 in FIG. 2C ).
[0060] FIG. 3 illustrates elemental processes occurring in the bulk of carbon barrier 16 upon permeation of said barrier 16 by the vapors evolving from the sublimation of the as-synthesized SiC charge 20 . These elemental processes include numerous and repeatable steps of vapor condensation, reaction between vapor and carbon, and re-sublimation of the SiC deposit. In FIG. 3 , incoming vapor 31 from the sublimation of the as-synthesized SiC charge 20 comes in contact with a carbon particle 32 of carbon barrier 16 , condenses on particle 32 and forms SiC deposit 33 . As a result of SiC deposition on particle 32 , vapor 31 becomes enriched with silicon, which enables vapor 31 to react further with the exposed portion of carbon particle 32 to form additional solid SiC (in other words, to convert carbon particle 32 into SiC). In turn, the SiC deposit 33 sublimes and produces SiC vapor 31 a which condenses on another carbon particle 32 a in the form of SiC deposit 33 a . These elemental steps are repeated multiple times on carbon particles 32 , 32 a , etc. that form the bulk of carbon barrier 16 .
[0061] At every elemental cycle of SiC sublimation-reaction-condensation, the mass balance holds for every impurity. Upon sublimation, an impurity contained in the solid SiC (i.e., the carbon particles 32 , 32 a , etc., that are converted into the solid SiC) is released into the surrounding space in the form of volatile molecular species symbolized by arrow 34 . A fraction of the released impurity diffuses across a graphite wall 37 of crucible 11 to the exterior of crucible 11 . This diffusion is symbolized by arrow 34 a . Upon condensation of vapor 31 a on carbon particle 32 a , the remaining fraction of the released impurity is absorbed from the surrounding space by the growing SiC deposit. This released impurity absorption is symbolized by arrow 34 b.
[0062] Hence, the overall degree of impurity removal depends on: (i) chemical affinity of silicon carbide for the impurity; (ii) “transparency” of graphite to the impurity-bearing volatile molecules and (iii) concentration (partial pressure) of impurity in the exterior space.
[0063] It is known in the art of SiC sublimation growth that graphite is substantially transparent to gases, such as nitrogen. Therefore, nitrogen released in the process of SiC sublimation described above can be efficiently removed from the interior of graphite crucible 11 by the operation of pump(s) 4 via nitrogen diffusion across the wall 37 of crucible 11 , provided that the partial pressure of the nitrogen in furnace chamber 10 is low.
[0064] It is also known that transparency of the graphite forming graphite crucible 11 to Si-bearing vapors formed in the process of SiC sublimation described above is substantially poor. Therefore, only minor losses of Si from crucible 11 are incurred in stage (b) of SiC synthesis.
[0065] In summary, repeated cycles of condensation-reaction-sublimation take place in the bulk of carbon barrier 16 during SiC vapor transport across said carbon barrier 16 from mixture 15 toward the top of crucible 11 until the final polycrystalline SiC grain material 23 has been prepared. These cycles are accompanied by removal of impurities from the interior of crucible 11 , including nitrogen, and nucleation and growth in the bulk of carbon barrier 16 of hexagonal polycrystalline SiC grain material 23 with linear particle dimensions or diameters between 0.2 and 2 mm. The duration of phase (b) of SiC synthesis is desirably between 24 and 72 hours.
[0066] The purity of the final polycrystalline SiC grain material 23 was characterized using GDMS and SIMS and was found to include B, Al and other metal contaminants in concentrations below their GDMS detection limits of 0.01-0.005 weight ppm. SIMS analysis was performed on larger crystallites (˜2 mm in size) recovered from synthesized batches of polycrystalline SiC grain material 23 and showed the levels of B below 6·10 15 atoms/cm −3 ; Al below 1·10 15 atoms/cm −3 ; and Fe and Ti below 3·10 14 atoms/cm −3 . The levels of background nitrogen were found to be consistently below 8·10 15 atoms/cm −3 (close to the lower nitrogen detection limit of SIMS).
[0067] With reference to FIGS. 4A and 4B , polycrystalline SiC grain material 23 synthesized in the manner described above was used as a source in growth by sublimation of vanadium-doped semi-insulating SiC crystals. In preparation for such growth, polycrystalline SiC grain material 23 was loaded on the bottom of a graphite growth crucible 100 , while a SiC seed crystal 102 was attached to a lid 104 of the growth crucible 100 .
[0068] A graphite capsule 110 was prepared and charged with a vanadium dopant 112 , in the form of elemental metallic vanadium or a suitable solid vanadium compound. Capsule 110 includes a calibrated capillary 114 of 1 mm in diameter and 3 mm long extending between an interior 116 of capsule 110 , where the charge of dopant 112 resides, and an exterior of capsule 110 . Capsule 110 with vanadium dopant 112 in interior 116 is placed in growth crucible 100 and buried under polycrystalline SiC grain material 23 at the bottom of crucible 100 (see FIG. 4B ).
[0069] Growth crucible 100 with vanadium charged capsule 110 buried in polycrystalline SiC grain material 23 was placed into a furnace chamber (like chamber 10 in FIG. 1 ). The chamber was then evacuated and filled with high-purity argon from an inert gas source (like inert gas source 6 in FIG. 1 ) to a pressure of 10 Torr. Then, crucible 100 was heated via a heater 120 (like heater 13 in FIG. 1 ) to a growth temperature, e.g., between 1900° C. and 2400° C., in such a fashion that a vertical temperature gradient was created wherein the temperature of polycrystalline SiC grain material 23 was higher than the temperature of SiC seed crystal 102 by 10 to 50° C.
[0070] As is known in the art, at high temperatures, e.g., between 1900° C. and 2400° C., the silicon carbide of the polycrystalline SiC grain material 23 sublimes releasing a spectrum of volatile molecular species of Si, Si 2 C and SiC 2 to the vapor phase. Driven by the temperature gradient, these species migrate via a vapor flow, represented by arrows 122 in FIG. 4B , to SiC seed crystal 102 and condense on it causing growth of a SiC single crystal 124 on SiC seed crystal 102 . Simultaneously, vanadium-bearing molecular species are released from the vanadium dopant 112 in capsule 110 via capillary 114 and are transported with vapor flow 122 to the growing SiC single crystal 124 and absorbed on the growth interface thus causing doping of growing SiC single crystal 124 with vanadium. More details on vanadium doping can be found in U.S. Pat. Nos. 5,611,955; 7,608,524; 8,216,369 and US Patent Application Publication No. 2011/0303884.
[0071] The growth of SiC single crystal 124 of 6H polytype and the growth of a separate SiC crystal 124 of 4H polytype containing from 8·10 16 atoms/cm −3 to 1.2·10 17 atoms/cm −3 of vanadium, respectively, were determined to be semi-insulating and exhibiting a very high resistivity—between 1·10 11 Ohm-cm and 2·10 11 Ohm-cm for the 6H polytype SiC single crystal 124 and between 4·10 11 Ohm-cm and 5·10 11 Ohm-cm for the 4H polytype SiC single crystal 124 . A typical purity of the grown SiC single crystals 124 , regardless of polytype, with respect to B, Al, Fe and Ti determined by SIMS was 1·10 16 atoms/cm −3 ; 5·10 15 atoms/cm −3 ; 1·10 15 atoms/cm −3 ; and 5·10 14 atoms/cm −3 , respectively. The nitrogen content in the grown SiC single crystals, regardless of polytype, was below 1·10 16 atoms/cm −3 .
[0072] Alternate embodiments ( 11 ′, 11 ″, and 11 ′″) of crucible 11 are shown in FIGS. 5A-5C , respectively. It is to be appreciated that, in use, each alternate embodiment crucible 11 ′, 11 ″, and 11 ′″ described hereinafter is housed in chamber 10 ( FIG. 1 ) and is surrounded by insulation 12 like crucible 11 in FIG. 1 . Chamber 10 and insulation 12 have been omitted from FIGS. 5A-5C and heater 13 is shown in close proximity to each crucible 11 ′ and 11 ″ for simplicity of illustration. Accordingly, the absence of chamber 10 and insulation 12 , and the location of heater 13 in close proximity to each crucible 11 ′ and 11 ″ in each of FIGS. 5A-5C is not to be construed as limiting the invention.
[0073] In FIG. 5A , which is a cross-sectional view of an embodiment of crucible 11 ′ having a large height-to-diameter aspect ratio, the initial reactive mixture 15 (described above) is placed in the central or middle portion of crucible 11 ′ and is sandwiched between two high-purity, light-weight, bulk carbon barriers 30 . The heating geometry is such that heater 13 couples to the central or middle portion of crucible 11 ′. Due to axial heat losses shown by arrows 40 , the top and bottom of crucible 11 ′ are colder than the central part of crucible 11 ′, and vapor transport (shown by arrows 42 in FIG. 5A ) is directed towards the top and bottom of crucible 11 ′. Accordingly, formation of the high-purity polycrystalline SiC grain material 23 takes place in the top and bottom portions of crucible 11 ′, while the carbon residue 22 remains in the central or middle portion of crucible 11 ′.
[0074] In FIG. 5B , which is a cross-sectional view of a crucible 11 ″ having a large diameter-to-height aspect ratio, a tube 41 is disposed substantially coaxially along a central axis of crucible 11 ″. Tube 41 defines an inner cavity 42 which is open to the exterior. At temperatures of SiC synthesis (2200-2400° C.) radiative heat transport dominates. Hence, cavity 42 facilitates heat losses from the central, axial portion of crucible 11 ″ (heat losses from cavity 42 are shown by arrows 40 ). Inside crucible 11 ″, one or more low-density bulk carbon barriers 30 are placed axi-symmetrically around tube 41 , and the reactive mixture 15 is placed outside the bulk carbon barrier(s) 30 , i.e., between bulk carbon barrier(s) 30 and an outside wall 46 of crucible 11 ″. This geometry results in radial temperature gradients in an interior of crucible 11 ″. Accordingly, vapor transport (shown by arrows 21 ) and formation of high-purity polycrystalline SiC grain material 23 takes place around central tube 41 , i.e., in bulk carbon barrier(s) 30 , while carbon residue 22 forms between bulk carbon barrier(s) 30 and outside wall 46 .
[0075] In FIG. 5C , which is a cross-sectional view of a crucible 11 ′″ also having a large diameter-to-height aspect ratio, heater 13 ′ is a central heater which is disposed along a central axis of crucible 11 ′″. The initial reactive mixture 15 is placed in proximity to the heater, while one or more low-density bulk carbon barrier(s) 30 are placed around reactive mixture 15 in the outer area of crucible 11 ′″. This geometry results in vapor transport being directed outward, towards wall 46 of crucible 11 ′″ (shown by arrows 21 ), and high-purity polycrystalline SiC grain material 23 forming in the outer area of the crucible interior, i.e., in bulk carbon barrier(s) 30 , while carbon residue 22 forms between bulk carbon barrier(s) 30 and heater 13 ′ in FIG. 5C .
[0076] The present invention has been described with reference to the preferred embodiments. Obvious modifications and alterations will occur to those of ordinary skill in the art upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. | In a method of forming polycrystalline SiC grain material, low-density, gas-permeable and vapor-permeable bulk carbon is positioned at a first location inside of a graphite crucible and a mixture of elemental silicon and elemental carbon is positioned at a second location inside of the graphite crucible. Thereafter, the mixture and the bulk carbon are heated to a first temperature below the melting point of the elemental Si to remove adsorbed gas, moisture and/or volatiles from the mixture and the bulk carbon. Next, the mixture and the bulk carbon are heated to a second temperature that causes the elemental Si and the elemental C to react forming as-synthesized SiC inside of the crucible. The as-synthesized SiC and the bulk carbon are then heated in a way to cause the as-synthesized SiC to sublime and produce vapors that migrate into, condense on and react with the bulk carbon forming polycrystalline SiC material. |
[0001] This application claims the benefits under 35 USC 119(e) of the U.S. Provisional Patent Application No. 60/828,784 filed Oct. 10, 2006, herein incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The embodiments found in this disclosure are related to manufacturing surfaces with the axis decentered from the spindle axis. In particular, one embodiment is related to compensating for tool geometry in cutting processes that involve an oscillating tool.
BACKGROUND OF THE INVENTION
[0003] Lathing lenses was the favored technique for producing rigid gas permeable lenses (RGPs). With the advent of computer numerical control (CNC) lathing contact lenses became a more viable means of mass producing lenses, although DSM (double-sided molding) processes may be the most preferred way.
[0004] Lathing may be a preferred technique for creating specialty lenses, such as lenses for presbyopia and astigmatism, or for custom lenses. As a manufacturing technique, lathing requires specific tolerances, much like any other process but tool wear/compensation may also require additional machining steps to achieve desired tolerances.
[0005] Lathing may be used to create front and/or back surfaces of lenses and/or of lens molds. In back surface lathing or machining, a blank or button may be used. The blank may be fed into a chuck to hold the button. Once the blank is held by the chuck, the spindle holding the chuck and button begins to rotate and feed or advance toward the cutting tools. Cutting tools may be made of various materials. Exemplary or preferred materials include extremely hard materials, such as diamonds and the like. The first step in lathing a lens or a mold is to lathe the blank into the proper part diameter. Next, a roughing tool may be used to cut the initial back surface geometry using a plurality of preprogrammed cuts. Typically another step is needed to make the final cuts. Each progressive path cut may be adjusted for depth and geometry by adjusting the feed or advance amount, and/or the spindle speed. The back surface of the blank/part may also be polished in any conventional manner.
[0006] After the back surface is machined, the front surface may be blocked. In this process, the part may be mounted onto a front surface tool using low melting point wax. This step of wax mounting is desirable to help avoid the potential situation wherein the back surface is not at right angles to the axis of the spindle, which may result in unwanted prism in the created mold or lens. After blocking/mounting, the front surface is lathed. Similar to the back surface lathing, the partially-finished part (button) is fixed into or onto a chuck to hold the partially-finished button. The partially-finished button must be located by the lathes, which is usually accomplished with a sensor probe that establishes the center reference point. This reference point allows a computer/controller in a computer numerical control lathe to calculate the amount the cutting tool must feed or advance in order to arrive at the required or desired center thickness of the lens.
[0007] The processes described above are typically used for symmetric designs. Oftentimes lenses and lens molds are needed that are not symmetrical, such as for example, lenses designed for presbyopia or astigmatism. These types of lenses and corresponding molds may have optical or manufacturing axes that are not the same axis as the spindle and/or the center of the lens. For example, the part may need to be cut from the point of maximum thickness, which may not be the geometric center of the part. Techniques used for creating these lenses or molds include offsetting the part such that the axis of the part aligns with the center axis of the spindle. This method is inefficient as the part must be moved multiple times to cut and finish the geometry. The present invention seeks to correct these and other deficiencies in the prior art.
[0008] As would be obvious to one skilled in the art, many variations and modifications of the embodiments found in this application may be effected without departing from the spirit and scope of the novel concepts of the disclosure.
SUMMARY OF THE INVENTION
[0009] In accomplishing the foregoing, there is provided, in accordance with one aspect of the present invention, a method for cutting a surface with the apex of a part decentered from the spindle axis, the method including the steps of aligning a decentralized apex with a spindle axis; defining a central axis as a radial distance from the spindle axis; characterizing part design as a series of points; translating the series of points into a stacked elevational map; storing the stacked elevational map as a first mini-file; compensating for tool geometry; creating a second mini-file with the geometry-compensated values; transmitting the second mini-file to a computer numerical control lathe; and cutting part material with an oscillating tool according to the second mini-file.
[0010] In embodiments and accordance with another aspect of the present invention, there is provided a method for compensating for diamond tool geometry which may include the steps of creating a representation of a part surface; calculating the X and Z values for specific locations; calculating the desired position of a diamond tool relative to the surface point to be cut; compensating for the diamond tool radius to determine proper tool position to generate recalculated points; and calculating a geometry-compensated zero meridian. The method may, in embodiments, include aspects wherein the step of creating a representation of a part includes representing a part surface as a spiral and defining meridians within the spiral. In still other embodiments, the step of calculating the X and Z values for specific locations may further include measuring the distance between two curves of the spiral, then dividing the distance between the curves by the number of meridians, and equating a Z value along the zero meridian.
[0011] In still another embodiment, the method may include aspects wherein calculating the desired position of a diamond tool includes projecting a line at the tool axis angle from the zero meridian to the meridian being compensated; and projecting a vector normal to the point determined in the preceding step to find the center of the diamond tool. The tool axis angle may be between about 0 degrees and about 45 degrees. In further embodiments, the compensating step may also include offsetting the desired surface location by the tool radius value perpendicular to the current meridian. The step of calculating a geometry-compensated zero meridian may further include rotating the recalculated points about the origin by a tool axis angle, and averaging the values of the highest and lowest meridians at each point calculated. The method may further include the step of recording all tool geometry compensated values in a mini-file. Exemplary surfaces or parts which may be produced according to the method of the invention include, for example, lenses and lens molds.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows an exemplary lens or surface of a lens mold in which the optical axis is not aligned with the central axis.
[0013] FIG. 2 depicts a build-map of the lens or surface of a lens mold of FIG. 1 .
[0014] FIG. 3 depicts a spiral representation of a lens or mold geometry.
[0015] FIG. 4 depicts the spiral representation of FIG. 3 with defined meridian points.
[0016] FIG. 5 depicts a representation of the tool geometry compensation method.
DETAILED DESCRIPTION
[0017] Reference now will be made in detail to the embodiments of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.
[0018] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein and the manufacturing procedures are well known and commonly employed in the art. Conventional methods are used for these procedures, such as those provided in the art and various general references. Where a term is provided in the singular, the inventors also contemplate the plural of that term.
[0019] The embodiments found herein seek to provide an efficient method for lathing a surface with the axis decentered from the spindle axis using an oscillating tool. This method is an improvement over the prior art and provides a method in which part “re-chucking” during the cutting operation is minimized.
[0020] Referring to FIG. 1 , a schematic of a side sectional view of lens design is shown. In FIG. 1 , lens 10 is shown in which the optical apex 20 is decentered from the central axis 30 of the lens 10 . In this embodiment, the axis of the spindle (not shown for clarity) is not aligned with the apex 20 of the part (lens), or point or maximum thickness of the part. Rather, the apex 20 of the part lies offset from the central axis 30 and the spindle axis, and may further be offset from the optical axis (shown as dotted line 40 ) of the lens 10 . The spindle axis and the optical axis may be aligned.
[0021] Computer numerical control lathing is accomplished by programming the lathe to cut according to a lens or mold design. This can be accomplished through mathematics and various types of software including software capable of representing a three-dimensional image and CAD/CAM software. For all purposes, however, the lens or mold design must be “translated” into a series of points that can be fit to a mathematically defined curve that the computer numerical control lathe can recognize and cut.
[0022] In one embodiment, the design may first be categorized by dividing it into sections. Once the design has been captured as a series of points, the design can be translated into a stacked elevational map of the part 70 , which may be such as a lens or mold, as shown in FIG. 3 . This information or data is stored as a “mini-file”, that is, a data file containing information which includes both the information for the header or identification of the lens, and information about the geometry of a lens, which data is in a form that is interpretable by a computer-controlled manufacturing device such as a computer-controlled lathe. Additional information relating to methods for converting a desired lens design to a geometry of a contact lens that is to be produced in a computer-controlled manufacturing system is disclosed in U.S. Patent Application Publication No. 20060055876A1, which published on Mar. 16, 2006.
[0023] The mini-file creates the build-map, for example, such as the build-map 50 shown in FIG. 2 . Each of the lines 60 illustrated in FIG. 2 defines a path that the cutting tool follows to cut that particular cross section of the lens. For purposes of clarity, only a few lines 60 are shown in FIG. 2 ; however, it is to be understood that many more paths for the cutting tool to follow may be and, conventionally are, described and utilized. Oscillating tools are defined by having a diamond cutting tool (or other cutting part) mounted on a Variform (available from Precitech, Inc., having offices in Keene, N.H.) or other suitable device which has the ability to oscillate as the spindle of the lathe rotates, creating a non rotationally symmetrical surface.
[0024] For oscillating tools, an additional step must be taken after a mini-file is created. This step, referred to as “tool geometry compensation”, is designed to compensate for the radius and shape of the diamond tool and is distinct from, for example, simple tool wear compensation. When the diamond tool oscillates in and out of the part, the computer numerical control system on the lathe calculates or controls the cut as if the diamond tip of the tool is a theoretical sharp, that is, a finite point not having an appreciable radius. In practice, any diamond tip has a radius that is unique for each diamond. If this tip radius is not compensated for, undesired effects will occur, such a tool drag across the part to be cut.
[0025] The first step in tool geometry compensation may include reading a pre-generated mini-file into a computer memory. Next, referring again to FIG. 3 , the spiral step-over distance (the distance between the meridian lines 74 along the spiral rings 72 , which spiral rings are generated during a machining/cutting process), is represented on the surface of the desired part design as shown in FIG. 3 . This spiral can be calculated based upon the appropriate revolutions per minute and feed rate specified by the tool compensation program or other source. The number of spiral rings (i.e., the number of revolutions) created is determined by the feed rate and spindle revolutions per minute. More spiral rings are created with slower feed rate and higher revolutions per minute.
[0026] Once the spiral step is plotted, the distance between two curves of the spiral is calculated. The number of meridians defining the surface of the part is pre-determined by the mini-file (for example, 24, 96, or 384 meridians). The meridians represent the cross section of the surface at a particular angle. When larger numbers of meridians are used, the size of the mini-file increases; however the representation of the actual surface is more accurate. The distance between any two spiral curves along a given meridian is then preferably divided by the number of meridians to establish the X location of each point 76 on the meridian as is shown in FIG. 4 . For purposes of clarity, only 4 location points 76 are shown in FIG. 4 ; however, it is to be understood that many more points may be described and utilized.
[0027] Referring to FIG. 5 , one aspect of the compensation methodology is shown. After the X location of the uncompensated surface points is established, the X location may be matched to the Z location on the zero meridian shown as line 100 . The zero meridian 100 is a 2-dimensional path that corresponds to the defined path of the lathe slides, which is preferably an average of all of the meridians. The X locations are indicated by the current slice diameter, represented by line 250 . For every X location along line 250 there is only one Z location on the zero meridian 100 . For each point on the zero meridian 100 , a line 200 (the tool axis angle) may be projected at the oscillating tool angle until it intersects the meridian being compensated (current meridian 150 ). This tool axis angle 200 is set as defined in the lathe configuration, and may be of any angle between and including 0 degrees and 45 degrees.
[0028] At the intersection of the projected line 200 (the tool axis angle) from the preceding step and the current meridian 150 being compensated, a new vector (not shown) may be projected normal to the meridian being compensated 150 to find the center 300 of the diamond tool represented by circle 350 . The radius of the diamond tool is known and hence, can be programmed. This point 300 represents the uncompensated diamond tool center. Referring to FIG. 5 , the intersection of a horizontal tangent line (shown as dotted line F-H) and the diamond radius is the theoretical sharp; a diamond with a radius of 0. The center of the diamond having a radius of 0, on this lathe is taken to be point “G”, which is depicted by location G in FIG. 5 . Location G is the location where the cut may be applied to adhere to the lens design. A different “location G” exists for each X and Z. The collection of all of the generated location G's (for each X and Z) is the true compensated surface for the particular diamond tool. The true compensated surface is to compensate for the diamond radius, which is unaccounted for in the lathe software for an oscillating surface, the value of the theoretical sharp is used to determine the geometry-compensated position. The value for the theoretical sharp is determined by the type of lathe used and the lathe compensation program. This process is repeated for each meridian in the spiral to create a series of new points.
[0029] Furthermore, the intersection of horizontal tangent lines and vertical tangent lines bounding the diamond radius describe a square such as the square shown in FIG. 5 described by horizontal lines A-C and F-H, and vertical lines A-F and C-H. In some embodiments and/or for other tooling equipment, the value used to determine the geometry-compensated position may be at point or location “A” as described above, while for other embodiments and/or for other tooling equipment, the value may be at any of points A, B, C, D, E, F, G or H as shown, where points or locations A, C, H and F are located at the intersections of the horizontal and vertical tangent lines, and points B, D, E and G are located at the intersection of the horizontal and vertical tangent lines with the diamond radius.
[0030] After all points are determined according to the above method, a new zero meridian must be calculated. This is accomplished by theoretically rotating all calculated values about the origin at the tool axis angle and calculating the average of the highest and lowest meridians. This average represents the new geometry-compensation zero meridian, which compensates to create the correct tool cutting path for the lathe slide to follow. After these calculations are completed the new values are saved as a second mini-file. This mini-file is then transmitted to the computer numerical control lathe.
[0031] The invention has been described in detail, with particular reference to certain preferred embodiments, in order to enable the reader to practice the invention without undue experimentation. A person having ordinary skill in the art will readily recognize that many of the previous components, compositions, and/or parameters may be varied or modified to a reasonable extent without departing from the scope and spirit of the invention. Furthermore, titles, headings, example materials or the like are provided to enhance the reader's comprehension of this document, and should not be read as limiting the scope of the present invention. Accordingly, the invention is defined by the following claims, and reasonable extensions and equivalents thereof. | The present invention is related to manufacturing surfaces with an axis decentered from the spindle axis. In particular, the present invention is related to compensating for tool geometry in cutting processes that involve an oscillating tool. |
This invention relates to door holders, and more particularly, to door holders operative to selectively position the door responsive to movement of the door itself.
BRIEF DESCRIPTION OF THE INVENTION
1. Description of the Prior Art
The function of securing doors, lids, hatches, and other closure devices, in an open or partially open position, has been carried out in a variety of ways. Hooks are used to fasten open doors to adjacent walls. Chains are frequently used to permit doors to rest in positions determined by the length of the chain. Wedges and blocks are used to restrict door movement. When hydraulic closers are part of the system, means may be provided for restraining movement of the piston arm.
Most door holding devices require an operator to manually set them into the desired position. This, in turn, presupposes that the operator has his hands free to manipulate the devices. Many devices must be seen to permit the operator's manual adjustment, and cannot be easily set in conditions where the light is dim, or nonexistant. A large majority of door holding devices require some degree of manual dexterity and some cannot be manipulated by persons with physical handicaps.
2. The Present Invention
The present invention is a door holder suitable for attachment to almost all hinged or pivoted closure members, which are biased to a closed condition, by springs, gravity, or other means. The invention permits unrestricted opening and closing of such a closure member unless and until the operator chooses to set the member in a particular open position. "Setting" or positioning the member in the particular open condition is accomplished by stopping the opening action and releasing the door to return slightly under influence of the door closure biasing means, without touching the door holding unit. Thus, the operator may merely touch the member with his shoulder or hip and position the member open, or release it from a previously set position.
An object of the invention is to provide an improved door holder.
Another object of the invention is to provide an improved door holder that permits the door to usually open and close without restriction and which does not require manual dexterity to set it.
Another object of the invention is to provide an improved door holder that is set by touching only the door itself, and not the holder.
Another object of the invention is to provide an improved door holder that can be attached to existing doors and which operates in conjunction with all door closure mechanisms.
In accordance with a particular embodiment of the invention, these objects are achieved with a door holder having an outer housing connected to a door or other closure member, and catch housing connected to the adjacent frame or jamb. A catch device within the catch housing is a cam follower designed to cooperate with a cam surface on the outer housing. The catch device is adapted to be "set" in several positions that render it either operative to hold the door in a particular position, or to permit unrestricted movement. Setting includes merely stopping the door at the general position to be maintained, when the catch device generates an audible signal.
The above, and other objects of this invention will be more clearly understood and appreciated from the following detailed description, taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of an embodiment of the invention connected between a door and jamb;
FIG. 2 is an enlarged view showing the internal mechanism of an embodiment of the invention as the catch is cocked ready to either permit further opening of a connected door, or to permit the door to close without impediment;
FIG. 3 is an enlarged view of an embodiment of the invention wherein the catch is engaged at a track stop surface, holding the door open in a selected position;
FIG. 4 is a side view of the preferred embodiment of the invention, showing the portion of the device in FIGS. 2 and 3, with the catch element over a stop opening;
FIG. 5 is a cross-sectional view taken along the lines 5--5 of FIG. 3;
FIG. 6 is a cross-sectional view of the spring pin assembly taken along lines 6--6 in FIG. 2;
FIG. 7 is a cross-sectional view of the spring pin and swivel assembly taken along lines 7--7 in FIG. 6;
FIG. 8 is a cross-sectional view of the spring pin and swivel assembly taken along lines 8--8 in FIG. 6;
FIG. 9 is a side view of an embodiment of the invention, showing the control mechanism in combination with a hydraulic closure device;
FIG. 10 is a cross-sectional view taken along lines 10--10 in FIG. 9; and
FIG. 11 is a cross-sectional view taken along lines 11--11 in FIG. 9.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, it will be seen that door holder 10 is adapted to be mounted between a door 11 and jamb 12. The door is adapted to rotate about jamb 12 by hinge member 13. Although not shown, it is to be understood that the door is biased to a normally closed condition by either a spring, hydraulic closer, gravity, or some equivalent means. Door holder 10 is pivotally connected to door 11, by a door mounting element 15. It is also pivotally mounted to the jamb by jamb mounting element 14. As will be evident from the following description, the door holder has cooperating elements consisting of an outer housing 25 and catch housing 26 which are adapted to telescopically cooperate permitting respective camming surfaces to carry out the features of the present invention. The outer housing 25 may be formed by bending a flat material into an elongated chamber suitable to slidingly receive said catch housing 26. In this case, one surface area of outer housing 25 may be formed as the camming surface to define particular locations that will effect selective actuation of the catch means described hereinafter.
FIGS. 2 and 3 illustrate separate positions of the outer housing and catch housing when the door is in different positions. These FIGURES should be considered together in order to appreciate a typical operating sequence.
When door 11 is closed, catch 21 resides in a quiescent condition cocked with its leading surface 33 resting against the inner surface of catch housing 26. It is held in this position by pressure at the spring pin notch 24, exerted by spring pin 23. This pressure is achieved due to the compression of spring 41.
As the door is opened, the catch sliding cam surface 28 moves against the inside surface of outer housing 25. When the door reaches a predetermined hold position (either 30°, 45°, or some other position selected by the location of a notch in the outer housing 25) catch 21 drops into the slot coming to a stop with an audible click as the catch back surface 32 of catch 21 comes into contact with the inside surface of catch housing 26. If the door is released at this time, catch lock surface 31 will come into contact with track stop surface 29 and hold the door fixed. If this position is 30 or 45 degrees, it will allow medium-sized packages to be passed through the door. Where the door is a hatch cover, it may be a position established to provide ventilation.
By continuing to move the door further in an open direction, the catch 21 automatically releases as cam follower surface 28 moves over the cam surface 27. Thereafter, if the door is released while the follower is in this condition, it will proceed unimpaired back to a closed condition.
If it is not desired to hold the door open, catch 21 will continue sliding back on surface 32 until the cam surface 28 contacts track cam 27 causing the spring pin 23 to move up with the catch until the spring pin notch 24 is above the center of both the catch locking pin 22 and the spring swivel 34. Under these conditions, the catch leading surface 33 will engage the inner surface of catch housing 26 and the door will be free to close. When the catch lock surface 31 is in an up position, it passes over track stop surface 29 as the door closes, until the trigger cam surface 30 contacts track cam 27 flipping the catch back down on sliding surface 28 and back to its original starting position where it is cocked and ready to either hold the door open or make another passive "roundtrip".
In order to hold a door all the way open, a second track stop surface 29 is provided in the outer housing 25. After the first track cam 27 is passed, and the catch 21 is cocked upwardly, it will slide with its leading surface 33 upward and its trigger cam surface 30 downward. When catch 21 approaches the second track slot, trailing cam surface 25 will contact track cam 27 flipping the catch 21 down so it can drop into the second slot and make contact between the catch lock surface 31 and track stop surface 29. In order to release the door from this second open position, it is simply pushed slightly further forward pulling catch 21 over track cam 27 to again cock it into an upward position. Now, the door can be released and it will travel the entire trip back to a closed condition.
To more fully understand the important features of the invention and the interrelated structures that cooperate to achieve the objectives of the invention, consideration will be given to a number of the critical elements. These elements are shown enlarged in FIGS. 5 through 8.
The catch 21 is the locking member between the inner catch housing 26 and the outer housing 25. It is attached by a catch locking pin 22 to the catch housing. All movements of the catch 21 are fully automatic. They are controlled by simply the opening and closing of the door. In this embodiment there is a choice of two holding positions. The first secures the door halfway open and the second secures the door in a fully opened position. Each "hold" position is located by an audible click. By releasing the door at this point it is automatically set into the "hold" position. In order to release the door, it is moved a few degrees, or few inches, beyond the "hold" point providing the clicking sound again, and cancelling the "hold" action from taking place.
Catch holding pin 22 is provided to hold the assembled elements of the catch and housing together. This can be seen more clearly in the cross-sectional view of FIG. 5. When the catch 21, catch locking pin 22, spring pin 23, spring pin swivel 24, and spring 41 are assembled in proper sequence, the assembly remains interconnected without the possibility of dis-assembly until physically taken apart. In order of assembly, the catch 21 is positioned within housing 26; catch locking pin 22 is inserted within the catch; spring 41 is then mounted upon pin 23 and the pin is positioned within the aperture in swivel 34. Pin 23 is then engaged within notch 24. The swivel 34 is held in place by the width of spring pin 23 and spring 41, which in turn are locked between swivel 34 and the notch 24.
Catch spring pin 23 transfers the pressure of spring 41 to catch 21 in order to keep it at all times either in an up (open) or down (cocked) position against outer housing 25. The front portion of spring pin 23 fits into the spring pin notch 24 in catch 21 and provides an area for the spring 41 to push against.
The swivel 34 allows spring pin 23 to move up and down with catch 21. It rotates with spring pin 23 and the associated spring 41, providing a backstop for the spring and allowing pin 23 to move backward and forward as well as up and down. As noted previously, an important function of swivel 34 is to provide means for easy assembly of the catch and cocking components.
The inner catch housing 26 slides with a telescoping action inside outer housing 25. It is the mounting vehicle for the catch and spring pin assembly. It attaches to the door jamb and by its action with catch 21, engages to lock with the outer housing 25 when the door is in one of the "hold" positions.
There may be several embodiments of outer housing 25. These depend upon the particular type of closure device employed on the door. For example, a spring may be mounted between the door mounting element and jamb mounting element. Alternatively, the type of hydraulic closer disclosed herein may be provided between these elements.
FIGS. 9-11 illustrate the mounting of the mechanism of this invention in conjunction with a typical hydraulic closure cylinder 50. It will be understood that such cylinders are designed to return any opened door or cover to a desired closed position.
Cylinder 50 is pivotally connected via arm 51, and pin 40, to jamb mounting bracket 14a. As the door element is opened, arm 51 extends within cylinder 50. The outer housing 25 of the holding mechanism of the invention is affixed to the bottom of the cylinder 50, as shown in FIG. 9. Shoulder 37 rests against the rear of cylinder 50, and absorbs the force exerted against the unit when the door is held open, thereby relieving any strain on the connection between the housing 25 and closure cylinder 50. Bracket 36 rigidly connects the catch housing 26 to a threaded portion of pin 40 and thus to the jamb mounting bracket 14a.
The outer housing 25 is preferably attached to cylinder 50 along its longitudinal dimension, by mounting flanges or strips 38. These flanges may be flexible or rigid elements provided with an adhesive coating to assure simple and aligned connection between the parts. For additional mounting security, a band 44 may be used at the remote end of cylinder 50.
Particular embodiments of the invention have been shown and described. Modifications of these embodiments will be apparent to those skilled in the art. All such modifications coming within the scope of the following claims, are intended to be covered thereby. | A door holding mechanism having interacting members with cooperating cam surfaces that selectively, by touch, effect locking or sliding movement to permit unrestricted door movement or rigid positioning in partial open conditions. |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of application Ser. No. 13/315,996 filed on Dec. 9, 2011 which is a continuation of and claims priority to application Ser. No. 12/183,771 filed on Jul. 31, 2008, and issuing as U.S. Pat. No. 8,075,783, which itself claims priority to U.S. Provisional Patent Application Ser. No. 60/952,965, filed Jul. 31, 2007, the disclosures of which are herein incorporated by reference in their entirety, and all commonly owned.
FIELD OF THE INVENTION
[0002] The present invention relates to systems and methods for water remediation and biosolids collection, and, more particularly, to such systems and methods for remediating water and collecting water-borne solids using solids entrapment.
BACKGROUND
[0003] Dissolved air flotation (DAF) is a liquid process technology that uses micro-bubble air flotation to raise and remove suspended solids in an aqueous solution such as industrial process water, municipal waste water, and/or lake water.
[0004] DAF systems known in the art are constructed from steel or concrete tanks. Large liquid above-ground vessels require structural steel plate and backing stiffeners to preclude deformation of the tank walls during hydrostatic loading when full to operating levels. The steel vessels also require footings to transfer loads to soil with appropriate bearing capacities. Inert materials like 314 and 316 Stainless Steel or exotic epoxy coating systems are typically used to retard corrosion.
[0005] Wind mixing of shallow lakes causes loose non-photosynthetic sediment material to rise into the photic zone temporarily. This reactive nutrient-laden sediment often feeds the algae in the photic zone of an impaired (hypereutrophic) lake and causes a perpetual algal bloom, which can in some cases even be seen from space (the orbiting Space Shuttle can differentiate hypertrophic Lake Apopka in Florida from other lakes, for example). One means of water remediation is to remove, or harvest, suspended solids (SS) and the nutrients incorporated thereinto.
[0006] Traditional approaches for SS removal use large expanses (5,000-45,000 acres) of flooded wetland filters where quiescent conditions cause the SS to sink out and form soil. As soil decays, much of the settled-out nutrients go back into solution, causing inefficiency. If toxic cyanobacteria algae settle out in the wetland, toxins can become available to wildlife for years, both in soil and water. Still, this has been a preferred method for remediation where a great expanse of land is available.
[0007] A known difficulty in remediating water bodies is that systems must often operate where the soil is soft and wet, for example, adjacent or on lake shores. The expense associated with providing excavation, fill, and soil stabilization can be prohibitive, and the result unsightly in an area that is supposed to be being improved. Therefore, DAF systems have been considered unsuitable for on-site water body remediation. In addition, for at least some of the same reasons, using DAF technology in a water body has not been considered to be practicable.
[0008] Prior known DAF systems require a precise balancing of criteria such as inflow rate, coagulant delivery parameters, and sludge and flotation removal in order to function effectively. As larger DAF systems are known to be prohibitively expensive, the trend has been towards smaller vessels having specific geometries for optimizing filtration.
[0009] Other problems faced at the present time are the growing expense and decreasing supplies of fuel, and the disposal of biomass generated by bioremediation systems such as algal floways and other aquatic plant systems.
[0010] Therefore, it would be desirable to provide a system and method for remediating a body of water that is economical and effective, and that does not disturb an aesthetic appeal of the water body and the surrounding area. It would also be desirable to provide a system and method for disposing of collected biosolids and for generating fuel therefrom.
SUMMARY
[0011] The present invention is directed in one aspect to a vessel construction that is innovative over and is significantly less costly than known water remediation and biosolids collection constructions. The present system includes structural differences from previously known systems, wherein flexural tension and compression capacity are provided by an extant support structure, such as soil or a body of water or a combination thereof.
[0012] The present invention achieves SS and dissolved solids removal by an innovative scale up of a solids entrapment process, such as, but not intended to be limited to, DAF. While DAF systems do not settle out 100% of the SS, they sequester and process all that they do remove, precluding release back into the surface water. This results in a huge increase in the nutrient removal per unit area when compared to known wetland techniques. Further, elements such as toxic algae are safely removed from the ecosystem, avoiding wildlife exposure.
[0013] Many scientists, such as the team at the St. Johns River Water Management District (SJRWMD), have studied solid removal systems such as DAF for application in polluted lakes such as Lake Apopka, Fla., as well as other surface waters, but found the scale of traditionally manufactured process components to be far too small and not economically feasible for the mammoth flow required for lake-scale applications. The present invention teaches a vessel construction and use that includes finely contoured excavations, geo-membrane technologies for soil, and inexpensive liner membranes to build a basin that does not require foundations or expensive steel or concrete vessels. Wind, gravity, tensile, flexural, and compressive loads from liquid pressure do not need to be resisted by the moisture barrier component of the vessel, thus greatly reducing the cost to construct a very large vessel.
[0014] A system for remediating a body of water and collecting suspended and dissolved solids therefrom is provided. The system comprises a water-impervious lining that is positionable in a depression in or adjacent a body of water desired to be treated. The lining and depression define outer boundaries of a treatment vessel, which comprises a treatment portion having an inlet for receiving water to be treated, an outlet portion for containing treated water, and an outflow weir between the treatment portion and the outlet portion. The outflow weir extends to a top end higher than a water surface, and across the vessel to side edges sealed against the opposed sides of the vessel.
[0015] Means are provided for transporting water to be treated from the water body to the treatment portion, for delivering an entrapment element to the transported water, and for mixing the entrapment element with the transported water. The entrapment element is for capturing suspended and dissolved solids in the transported water and effecting a separation between the captured solids and water cleansed therefrom. Means are also provided for removing the captured solids from the treatment basin. The cleansed water is movable through a channel in the outflow weir into the outlet portion.
[0016] The entrapment element can comprise one or more of a number of elements, such as, but not intended to be limited to, dissolved gas bubbles, a coagulant, and a flocculant.
[0017] In an embodiment, the vessel comprises an inflow baffle positioned adjacent an inlet end of the vessel. The inflow baffle extends from a bottom of the vessel at a bottom end to a top end beneath a water line in spaced relation from a top edge of the vessel, and extends across the vessel to side edges sealed against opposed sides of the vessel. The inflow baffle and an inlet portion of the vessel sides containing the inlet end thereby define an inflow basin. In some embodiments, the inflow baffle is not employed.
[0018] The vessel further comprises an outflow channel adjacent an outlet end of the vessel, adjacent the vessel bottom, and in spaced relation from the vessel top edge. The channel provides a pathway for cleansed water, which typically will reside at and adjacent the vessel bottom, to exit the vessel, while retaining floating material in the vessel for removal therefrom.
[0019] In a particular embodiment, the channel can be formed by an outflow weir that extends from a bottom end in spaced relation from the vessel bottom to a top end at least as high as the vessel top edge, and extends across the vessel to side edges sealed against the opposed sides of the vessel. The outflow weir and an outlet portion of the vessel sides containing the outlet end thereby define an outflow basin. The inflow baffle, if present, and the outflow weir define a treatment basin therebetween; if there is no inflow baffle, the inlet end and the outflow weir define the treatment basin.
[0020] In another embodiment, the channel can be formed by an aperture through the vessel outlet end, the aperture positioned adjacent the vessel bottom and in spaced relation from the water surface.
[0021] In a further embodiment, the channel can comprise piping having an inlet adjacent the outlet end, adjacent the vessel bottom and in spaced relation from the water surface. Pumping can then remove cleansed water through the piping.
[0022] Means are further provided for removing the bubbles and captured suspended solids from the water surface in the treatment basin. Water cleansed of the suspended solids can move through the outflow channel to a desired destination, for example, back into the water body.
[0023] In another embodiment for use with floating vessels, a DAF system may not be included, and solids entrapment means can be employed such as coagulants and/or flocculants, alone or in combination. An inlet of the floating vessel channels water to be treated to a treatment zone, wherein the solids entrapment means is added to the water and mixed. The entrapped solids will either float or sink, depending upon the type of entrapments means used. Water from which the solids have been removed is channeled out from the vessel, and the entrapped solids are collected and ultimately removed from the vessel.
[0024] The features that characterize the invention, both as to organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description used in conjunction with the accompanying drawing. It is to be expressly understood that the drawing is for the purpose of illustration and description and is not intended as a definition of the limits of the invention. These and other objects attained, and advantages offered, by the present invention will become more fully apparent as the description that now follows is read in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF DRAWINGS
[0025] FIG. 1 is a top plan view of an exemplary dissolved-air-flotation device for the removal of suspended solids in wastewater.
[0026] FIG. 2 is a side cross-sectional view of the embodiment of FIG. 1 .
[0027] FIG. 3 is a side cross-sectional view of an embodiment for immersion in a body of water.
[0028] FIG. 4 is a side cross-sectional view of an embodiment having no separate inflow basin, and including piping for channeling cleansed water out of the treatment basin.
[0029] FIGS. 5 and 6 are top plan and side cross-sectional views of an embodiment wherein a channel is formed around an outlet portion of the vessel using suspended weirs, and floating material is removed from a gutter.
[0030] FIG. 7 is a top plan view of an embodiment for use with flowing water.
[0031] FIG. 8 is a side cross-sectional view of an inclined earth wall.
[0032] FIG. 9 is a side cross-sectional view of a sloped earth wall.
[0033] FIG. 10 is a side cross-sectional view of a device for dewatering collected floating material.
[0034] FIGS. 11 and 12 are top plan and side cross-sectional views of a floating platform or barge for remediating water and collecting entrapped solids.
[0035] FIGS. 13 and 14 are top plan and side cross-sectional views of a floating, modular water-remediation and entrapped solids collection system
[0036] FIG. 15 is a side cross-sectional view of an alternate embodiment of the system of FIGS. 13 and 14 for collecting settled entrapped solids.
DETAILED DESCRIPTION OF EMBODIMENTS
[0037] A description of preferred embodiments of the present invention will now be presented with reference to FIGS. 1-15 .
[0038] A DAF vessel 10 of the present invention has the following components: inflow zone, flotation cell zone, flotation collection zone, and outflow zone. Settlable solids drop to the bottom, and a collection system or underdrain piping periodically removes them. In a preferred embodiment 10 , solids float to the surface and are removed onto a ramp, also called a beach 16 , via chain and flyght scrapers or other methods. Typically 0.5 to 7 gpm flow per square foot of flotation zone can be used for sizing of filters depending on many variables. A preferred minimum depth is 12 in., and the depth can exceed 12 ft.
[0039] An important element of this flotation process is carefully crafted air micro-bubbles in solution. The generation of micro-bubbles can be accomplished with an air saturation tank, liquid high-pressure pump, and an air compressor in a system, which allows a clean side stream 17 of micro-bubble water to be held under pressure, for a period of time, so that when the pressure is released, tiny micro-bubbles form in the water feed tube 18 that ultimately release in the DAF basin and float SS up to the surface for collection. There are many micro-bubble generators 20 with various characteristics, depending on the specific application.
[0040] The rise within the DAF system 10 of the micro-bubbles is related to the size of the bubbles. The smaller the bubbles, the smaller the particulate matter that floats and the slower the rate of rise. An exemplary desired rate of rise is 1 ft/min, which can be achieved with bubbles 10 to 20 micrometers in diameter.
[0041] Minute concentrations of ozone or other coagulation means or chemicals bring together small particles by altering their surface charges so that they form larger particles or “flocs,” which can be floated by larger bubbles, with a faster rate of rise. Flocculation occurs during gentle mixing of water, coagulant, and SS. These variables contribute to an efficient DAF filtration system with balanced volume-to-flow ratios.
[0042] DAF systems are known for their ability to produce a waste stream of very high solids concentration, in the range of 1 to 5%. In large lake or surface water systems, this is a significant advantage, owing to the advance of material to dewater and dispose.
[0043] Algae are particularly difficult to dewater because surface charges cause the cells to repel each other. Evolutionary selection has suited planktonic algae with a hydration advantage. Because of their surface charge density, interstitial spaces remain between them that can retain water for surviving dry conditions, where crowding would isolate and kill closely buried cells.
[0044] Coagulation chemistry alters the ionic charge at the surface of algal cells and other SS, such that they come together to form a flake. This aggregated flake is of sufficient size that it can be floated with micro-bubbles introduced to the DAF inflow. A desired micro-bubble size range is 5-50 micrometers, with an optimal size in the 10-20 micrometer range.
[0045] Ozone pretreatment is known to greatly enhance coagulation chemical effectiveness, by as much as 90%. Ozone prepares the ionic charge and charge density so that small particles cling together by static charge. Ozone takes SS from a difficult-to-dewater state and helps consolidate SS, allowing greater water removal and de-watering.
[0046] The zeta potential can be defined as the potential of distance to charge density relationships on a microscopic particle. The zeta potential increases rapidly close to the surface of the particle, and decreases as the distance increases, at an accelerated rate. Coagulation chemistry is finally applied to satisfy and change the more neutral charge farther from the cell, so that it is drawn to adjacent cells. With this method, agglomeration and dewatering can be achieved more quickly than with evaporation alone. One or more coagulation chemicals or methods can be used for optimal results in different water systems or in the same water system depending on seasonal fluctuation and concurrent phytoplankton/SS speciation changes.
[0047] Some common coagulation chemicals can include: calcium hydroxide, calcium oxide, calcium carbonate, poly aluminum chloride (PAC, which can also serve as a flocculant, and is believed at the time of filing to represent the preferred embodiment), aluminum chlorhydrate, cationic polymers, anionic polymers, ferric chloride, and aluminum sulfate. Along with polymer chemicals, many other substances can be used to aid ozone coagulation, such as alginates and other natural products. Some common natural substances include: sodium alginate, clays, sodium in complex with other materials, macerated algal cells, powdered carbon, chitin, and starches.
[0048] The DAF provides synergistic benefits when configured in an ozone/DAF/periphyton sequence. Ozone/oxygen gas commences oxidation with rapid ozone-mediated reactions. Oxygen mediates follow-on reactions, which take considerably longer. An oxidation-reduction reaction requires up to 80 minutes to occur in the ozonation/oxidation of lake water. The main body of the DAF can be sized for sufficient volume to allow reactions to complete prior to entering the periphyton filter.
[0049] Electro-coagulation may be used with ozone and/or natural or chemical products for optimal coagulation. Electro-coagulation utilizes anodes and electric current to alter particle surface charges. A combination of one or more coagulation methods can yield a very cost-effective coagulation system.
[0050] The DAF system 10 also removes microinvertibrates in the inflow, keeping them from damaging aquatic plant like periphyton crops, which have been cultured to remove nutrients such as nitrogen and phosphorus.
[0051] As previously discussed, DAF technology is known for its ability to remove high solids content. This is much higher than other technologies, such as sand filters, which are typically below 1% in solids rejected. Handling of high-solids waste streams requires special pumping systems and handling considerations. Physically locating the DAF adjacent to the drying beds or thickening process, near the solids raking system, adjacent the DAF, allows for further thickening without high solids pumping or physical distribution with mechanized equipment.
[0052] One embodiment of a DAF system 10 ( FIGS. 1 and 2 ) induces micro-bubbles into a specially modified dirty water micro-bubble generator pump 20 receiving air from an air source 119 . The micro-bubble generator pump 20 forces compressed air into the pressure part of the pump 20 , and forces fluid through piping 17 receiving from the water body 65 . The formed micro-bubbles mix with the water and proceed to a saturation tube 120 , which comprises a wider section of the piping 17 . The saturation tube 120 provides the bubbles with residence time to distribute into the water. The saturation tube 120 is followed by a cracking valve 100 , which restricts flow and causes pressure to build in the saturation tube 120 to assist in bubble mixing. The micro-bubble solution then joins with the main flow 18 .
[0053] The main flow 18 proceeds through a serpentine pipe, along which are two injection ports in this particular embodiment 10 . Through a first injection port 103 is inserted a coagulant from tank 104 . Through a second injection port 106 downstream of the first injection port 103 is inserted a flocculant from tank 105 . In an alternate embodiment, the flocculant can be inserted directly into the inflow basin 29 . It is believed that coagulant causes biomass such as algae to form flocs, since the surface charge is altered. These flocs form among the micro-bubbles. The flocculant then attaches the flocs together around the bubbles.
[0054] This embodiment of a DAF filter system 10 has an inflow compartment or basin 29 into which the micro-bubble/influent mixture is pumped 39 through piping having a generally “U”-shaped end portion 40 into a manifold 15 having a plurality of apertures 41 , preferably pointing upwards. The water in the inflow basin 29 is allowed to sit undisturbed, substantially at zero velocity, to dissipate energy, which is preferred for light SS to separate and rise with the micro-bubbles. The water passes over an inflow baffle 28 having sealed sides 42 . The inflow baffle 28 extends from a bottom end 281 at the vessel bottom 43 to a top end 282 beneath the top edge 44 of the vessel 10 . This places the SS and bubbles 23 at the surface 36 , promoting a consolidation of floating solids/biomass to form. The inflow baffle 28 also contains any solids that are heavy and not influenced by the bubble interaction. A flotation chamber 19 downstream of the inflow basin 29 receives a blanket of floated SS 23 that is transferred to a collection point and removed by a conveyor 24 or other means. In some cases the inflow baffle 28 can be eliminated in lieu of a serpentine discharge manifold placed 1-2 ft below the water surface.
[0055] A solids raking system with chain, paddles (flyghts), and sprockets can be used to collect the floated SS 23 to a beach 16 , which lifts the SS off the water surface 36 and into a drying bed, geotube ( FIG. 10 ), or other dewatering equipment, where it is further dewatered. In cases where the DAF treatment basin 19 is so wide that the raking system has to span a great distance, semi-buoyant paddles can be used to reduce span requirements. Alternatively, a traveling rake can be used to push the floated SS 23 to the conveyor 24 .
[0056] One or more static or pneumatic blowers 21 can also be used to generate air currents to move the floating scum 23 to the conveyor 24 and beach 16 and into a collection receptacle 22 . In the embodiment illustrated, the conveyor 24 comprises a reversible device having a moving belt for conveying the raked scum 23 toward the beach 16 , or, in the other direction, another beach 16 ′ or collection vessel. Here the conveyor 24 extends across the treatment basin 19 from a first side 25 to an opposed second side 26 .
[0057] A drainage system under the DAF liner 27 can be used to allow sub-surface water and gases to vent and preclude displacement of the liner 27 from its desired location at the soil surface. A media-covered under-drain 11 can be positioned within the DAF chamber 19 for extracting all or part of the DAF during maintenance.
[0058] Many methods can be used to process the floated solids for disposal or use. One embodiment moves solids from the collection receptacle with a pump, which conveys the scum filtrate to a dewatering facility, which can be positioned nearby. A centrifuge can be used in some embodiments to dewater the floated scum to a wet cake, typically in the 20-30% solids range.
[0059] Alternatively, dewatering can be accomplished with the use of a geotube 200 ( FIG. 10 ), which receives the scum 23 via piping 201 . The geotube 200 is positioned on a surface 202 and is covered with a water-impermeable, for example, clear plastic, sheet 203 . Between the geotube 200 and the sheet 203 a fan 205 blows air, which creates a space 204 . The sun heats the space 204 , which assists in the dewatering process. Water exiting the geotube 200 exits through an underdrain 206 .
[0060] With a liner 27 as the sole containment means, an economical design method exists to build a very large DAF filter process unit 10 at low cost, when compared with conventional steel and concrete vertical structures with footings and foundations. This embodiment 10 provides an enhanced ability to use DAF technology well beyond the scale of traditional metal and concrete vessel designs, which have limitations due to construction cost. Geotextiles can be used in construction of the DAF liner 27 .
[0061] Effluent from the DAF system 10 flows under an outflow weir 38 that is sealed at the sides 42 , and extends from a bottom end 381 in spaced relation from the vessel bottom 43 to a top end 382 no lower than the vessel's top edge 44 . The outflow weir 38 seals off surface flow, entrapping the floating solids 23 in the flotation chamber 19 . The clarified effluent is then transferred from the outflow basin 30 by piping 31 . An effluent pump 32 having a float switch 34 can be used to pump the effluent to a lake or to follow-on process units such as ozone and/or periphyton filters and/or other process systems. In the embodiment shown in FIGS. 1 and 2 , the basin 19 slopes toward the upstream end 33 of the basin 19 , which permits solids to collect in and adjacent a pit 35 in the bottom surface.
[0062] Yet another DAF embodiment 140 ( FIGS. 5 and 6 ) comprises alternate forms of the floated material collection system and outflow weirs. Here the DAF basin 141 has a flexible sheet 142 suspended by a flotation element 143 affixed to a top edge 144 thereof. Along an inlet portion 145 of the basin 141 , the sheet 142 is weighted or affixed in some other manner at a bottom edge 146 to a bottom 147 of the basin 141 . Along an outlet portion 148 , the bottom edge 146 is in spaced relation from the basin bottom 147 . Thus, water entering the manifold 15 is discharged within an interior treatment portion 149 of the basin 141 , wherein floating material 150 rises to the water surface 151 . Cleansed water then exits under the bottom edge 146 of the sheet 142 to a peripheral portion 152 of the basin 141 , from which it can be pumped out. In a subembodiment, the basin bottom 147 is sloped so that the sheet's bottom edge 146 reaches the basin bottom 147 along the inlet portion 142 but is suspended thereabove along the outlet portion 148 .
[0063] The floating material 150 in this embodiment 140 is collected with the use of a movable rake 153 that skims across the water surface 151 and pushes the floating material 150 into a gutter 154 . The collected floating material 150 can then be pumped 155 from the gutter 154 .
[0064] Baffles can be made from the same membrane as the basin. Membrane material such as HDPE landfill liner, polyethylene, and a wide variety of synthetic rubber liners can be used, although this is not intended as a limitation. A geotextile drainage system 11 is also employed to allow removal of water from under the DAF liner 27 . This allows for predictable performance for the lined earthen basin 19 against ground water and gas discharge, which could displace the liner 27 .
[0065] An alternative embodiment of a DAF system 130 ( FIG. 4 ) contains no inflow basin, and, rather than having an outflow weir with a space therebeneath as in FIGS. 1 and 2 , the outflow channel comprises a pipe 131 extending through a constructed outflow weir 132 . This outflow weir 132 can comprise, for example, a concrete or other structure that extends from the bottom 133 of the DAF basin 134 to a top 135 at least as high as the water surface 136 . The pipe's inlet end 137 receives cleansed water from adjacent the basin bottom 133 and discharges water from an outlet 138 within an outflow basin 139 . As above, the cleansed water in the outflow basin 139 can then be transported therefrom to a desired location, such as back to the water body 65 .
[0066] In some applications a DAF system 50 can be floated ( FIG. 3 ) at the surface 66 of a body of water 65 , similar to a partially submerged boat hull. In this case, the construction can utilize light-gauge steel, aluminum, or fiberglass material for the walls 51 instead of a membrane, resulting in lighter structure and lower cost, and eliminating the requirement to resist land-based wind loads. A cover 52 can be used to isolate the DAF surface 53 against wind and jumping waves, which could corrupt the flotation process. A flotation collar 59 helps keep the system 50 afloat. A service barge can supply a motor-driven micro-bubble pump 54 , chemical storage, and filtrate storage basin. Water can flow out over check valve 105 back to the water body 65 ; however, if a wave flows toward the basin 50 , the check valve 105 will prevent inflow. This design uses no land and allows relocation of the DAF 50 with relative ease when compared with a land-based vessel. This boat-style DAF 50 is very well suited to dredging projects.
[0067] In the embodiment shown, the main inflow 55 joins the micro-bubble side stream 56 , through a coagulant injection point, to the inflow manifold 57 , again upstream of an inflow baffle 58 . Again, solids 60 collect on the surface 53 , and are collected with a scum rake 62 and scraped to a tender barge adjacent the floating DAF 50 , or are pumped directly to a land-based collection system. Cleaned water flows beneath an outflow weir 63 into an outflow basin 64 , from whence it exits the system 50 into the main basin 65 .
[0068] Additional floating embodiments may be contemplated ( FIGS. 11-15 ), wherein the vessel can be movable through the body of water, or passively floating. These embodiments can be used with or without a DAF system, and rely in large part on natural water movement, such as choppiness, currents, or wave action, or the movement of water relative to a moving vessel, to channel water to a treatment unit. The collected solids can contain such components as plankton varieties, microinvertebrates, and small fish, which can ultimately be processed into fuel such as biodiesel.
[0069] A system 180 including a floating platform or barge serving as a vessel 181 for remediating water and collecting entrapped solids is illustrated in FIGS. 11 and 12 . If the vessel 181 comprises a floating platform, anchors and tethers 182 (shown with dotted lines) are used to retain the vessel 181 in a substantially fixed location, and a pump may be used to draw water in. If the vessel 181 comprises a barge, during operation, the barge will be moving to create relative motion with the water body.
[0070] The vessel 181 has a water inlet, or aperture, 183 at an inlet end 184 , which in the case of a barge would be the forward end. The water inlet 183 has an opening 185 , and, in some embodiments, a plurality of openings 185 , in fluid communication with the water body 186 . A check valve 187 , such as a flapper check valve, although this is not intended as a limitation, is positioned along the inlet channel 183 . The check valve 187 serves to allow water to enter but not to escape, and also prevents the treatment basin 188 downstream of the check valve 187 from overflowing.
[0071] Downstream of the check valve 187 is positioned at least one port 189 for the introduction of an entrapment element 190 , such as a coagulant or a flocculant or a combination thereof. Following the at least one port 189 is a mixing pathway 191 , which can comprise in one embodiment a serpentine flow path created by a plurality of interdigitating curtains 192 that can be suspended from a cover 198 in an orientation such that their inner ends overlap. The mixing pathway 191 causes a turbulent flow to achieve blending of the entrapment element 190 into the incoming water.
[0072] The entrapment element 190 causes suspended and dissolved solids to coalesce and form either a floating mass or a settled mass, depending upon the system conditions. In the embodiment shown in FIGS. 11 and 12 , floating solids 193 are moved toward the outlet end 194 of the vessel 181 using a moving rake 199 , where they are collected in a gutter 195 or on a ramp 195 ′, or by other means, and then extracted to another location, on or off the vessel 181 . Cleansed water beneath the floating solids 193 flows out an outlet 196 at the outlet end 194 .
[0073] Another system 210 , 210 ′ including a floating platform or barge serving as a vessel 211 for remediating water and collecting entrapped solids is illustrated in FIGS. 13-15 . If the vessel 211 comprises a floating platform, anchors and tethers 212 (shown with dotted lines) are used to retain the vessel 211 in a substantially fixed location, and a pump may be used to draw water in. If the vessel 211 comprises a barge, during operation, the barge will be moving to create relative motion with the water body.
[0074] The vessel 211 is divided into a plurality of substantially parallel channels 231 , each of which has a water inlet 213 at an inlet end 214 in fluid communication with the water body 218 . The channels 231 can be formed, for example, by curtains 215 suspended from a cover 216 or from a flotation element.
[0075] The system 210 , 210 ′ comprises at least one port 219 for the introduction of an entrapment element 220 , such as a coagulant or a flocculant or a combination thereof. Following the at least one port 219 is a mixing pathway 221 , which can comprise in one embodiment a serpentine flow path created by a plurality of interdigitating curtains 222 that can be suspended from the cover 216 . The mixing pathway 221 causes a turbulent flow to achieve blending of the entrapment element 220 into the incoming water.
[0076] The entrapment element 220 causes suspended and dissolved solids to coalesce and form either a floating mass or a settled mass, depending upon the system conditions. In the embodiment 210 shown in FIG. 14 , floating solids 223 move toward the outlet end 224 of the vessel 211 , where they are collected in a ramp 226 , or by other means, and then extracted to another location, on or off the vessel 211 . Cleansed water beneath the floating solids 223 flows out an outlet 227 at the outlet end 224 .
[0077] In the embodiment 210 ′ shown in FIG. 15 , settled solids 223 ′ move toward a settling zone 228 at the bottom 229 of the vessel 211 , from where they are extracted. This embodiment 210 ′ can includes a floating curtain 230 as a cover. It will be understood by one of skill in the art that a combination of these embodiments 210 , 210 ′ could also be envisioned.
[0078] It will also be understood by one of skill in the art that an additional unit such as a DAF could be added to these systems 180 , 210 following the mixing pathways 191 , 221 to assist in solids entrapment.
[0079] A further embodiment of a DAF system 160 ( FIG. 7 ) can be used to cleanse flowing water from a river 161 , for example. In this system 160 the “basin” 162 comprises a side stream channeled from the river 161 , under control of a gate valve 163 at an inlet 164 . Coagulants 165 and flocculants 166 are injected 167 , 168 downstream of the gate valve 163 as above. Floating material 169 can be collected on a conveyor/rake 170 and beach collection area 171 as above, or by other means, and cleansed water flows under an outflow weir 172 , also as above, and thence to join the river 161 at an outlet 173 of the system 160 .
[0080] There are many possible uses for the solids removed from the DAF process. One such application is a soil amendment applied to soils poor in nutrients, where the tilth and macro- and micronutrients are amended. Another use is as a fluid soil culture system such as in sod culture over a membrane. Another use is as a fiber or filler in paper and paper product manufacturing process. Yet another use is as a feedstock for methane and ethanol, or other alcohol (e.g., butanol) production. Algal oil can also be extracted and processed into biodiesel. A further use is as a feed for animals.
[0081] The DAF vessel 10 can be constructed for use in floating applications where water in the basin supports the vessel walls, and greatly reduces the thickness of vessel walls, supporting structure, and foundations and allows mobile floating DAF for dredging or SS removal applications from surface waters.
[0082] The DAF solids can be connected to the outflow system directly adjacent to the DAF such that high-solids floatables can be dried without conveyance. Solids can be collected with a conveying pneumatic blower. Semi-buoyant paddles can be used on the rake system. Membrane baffles can be used with stiffening spars or elements to help them keep their desired planar geometry and position within the vessel.
[0083] In the creation of the liner for the systems 10 , 50 , geotextile or nursery ground cloth can be used, and excavations can have slopes steeper than the angle of repose of the soil 12 . If the walls are over-excavated and built in 6-12-in. lifts wherein fabric liner 27 is formed on a three-sided tube, this restrains the soil 12 and increases the horizontal shear over just soil alone. Higher, more vertical, soil-retaining wall structures can be built using this method.
[0084] A soil membrane DAF 70 ( FIG. 9 ) can be constructed in ground 71 below grade and perimeter bermed 72 , with a geotextile liner 73 as above supporting the water basin 74 . this embodiment 70 also illustrates a principle that can operate in any DAF embodiment, namely, subdivision into individual sectors 75 using “curtains” 76 that can have floaters 77 at a top end and an anchor 78 at a bottom end.
[0085] A similar system 80 can also be positioned above the existing grade, and/or manmade structures used to bolster the basin wall, or change the angle thereof, since it is currently believed that a steeper angle is preferable. In the system 80 shown in FIG. 8 , for example, a plurality of “fill cells” 81 can be created by laying geotextile liner 82 on the ground 83 and placing soil 84 or other material atop a portion of the liner 82 up to where the liner 82 is intended to define the basin 85 , leaving a length of liner 82 uncovered. This uncovered portion 86 can then be folded back over the compacted soil 84 , and this process repeated with additional cells 81 until a desired height is reached. If desired, a stiffening element 87 can be inserted between adjacent cells 81 to improve stability. When complete, another liner 88 is placed to line the basin 85 as above, and water 89 channeled thereinto. Well point dewatering techniques can allow in-ground construction where the water table is near the surface.
[0086] In another embodiment, excavations can simply rely on the natural angle of repose of the soil and incorporate cable- or float-supported membrane curtains to form the vertical walls of the liner-based, ditch-style DAF.
[0087] Ozone, DAF, and periphyton systems can be used in a modular system to remove microinvertabrates and particulate nutrients bound in algae and bacteria, as well as dissolved nutrients.
[0088] The collected material can be used as a soil amendment, hydro-seed carrier, and soil stabilizer. The collected material and other aquatic biomass can also be used in paper or a paper product, with or without coagulation chemicals and other substances to increase freeness, increase adhesion to fibers, and aid drainage. The SS and other aquatic biomass can be used in a fluid soil culture system with and without coagulation chemicals and other substances. The collected biomass can also be used to create hydrogen/biodiesel/alcohol fuels.
[0089] Another benefit of the systems of the present invention is that a certain degree of desalinization has been found to occur, approximately 50-60%, which could be extremely beneficial for the creation of fresh water from seawater.
[0090] Electro-coagulation can be employed for enhancing the performance of the soil and membrane DAF with and without other coagulation means. Natural and man-made chemical coagulants can be used with the liner DAF for enhancing the flotation characteristics of the DAF, with or without electro-coagulation and ozone. Geotextiles can be used for solids dewatering of algal solids from the soil and membrane DAF.
[0091] Solar drying and composting can be performed with algal solids from the soil membrane DAF and periphyton culture systems. Manipulation and use of DAF volume and concurrent residence time can allow for ozone and oxygen and oxidation-reduction reactions to complete prior to periphyton filtration.
[0092] A sump and manual vacuum system can be used for periodic sinkable particle removal.
[0093] Another aspect of the invention is directed to a means for harvesting aquatic plants and planktonic or other algae via a coagulation and acidification process that creates an algal nutrient in recycle water as it stabilizes CO2 in for uptake by aquatic plant culture systems, which can be used in bio-fuels generation and other uses.
[0094] In a preferred embodiment, algae harvested from process culture water is coagulated, or caused to collect in a floc, with the use of limewater. Calcium oxide, calcium hydroxide, and calcium carbonate (raw and processed forms of limestone) combined singly or together in water, cause a pH rise and disrupt repelling surface charges of small particles, causing them to collect and form a flake. These flakes are agglomerated with polymers into large flakes, which are easily floated to the surface and raked or blown off and collected.
[0095] pH correction can typically be required and can be effected by various means such as liquid acids, such as via carbon dioxide. If CO2 is used to adjust pH, a synergy occurs as the CO2 converts residual calcium oxide to bicarbonate, the form of carbon preferred by plants. When water is returned to the culture system, it is already amended with carbon. Additionally, this carbon is stable and will not off gas like dissolved CO2.
[0096] This culture water can be amended with other sources of nutrients from animal husbandry operations and wastewater plants, and this balanced nutrient media cultures more algae, which can be further bio-refined to produce energy.
[0097] Carbon dioxide is an atmospheric gas having a concentration of about 0.033% or 330 ppm. At room temperature, the solubility of carbon dioxide is about 90 cm3 of CO2 per 100 mL of water. In aqueous solution, carbon dioxide exists in aqueous form and come to equilibrium with H2CO3, carbonic acid. Carbonic acid is a weak acid, which dissociates to H++HCO3-(bicarbonate).
[0098] At this stage algal culture can take up the bicarbonate as a source if carbon, which is biofixed. Steps can be taken to sequester the carbon, or the algae can be digested, fermented, or gasified to produce energy.
[0099] The carbonate ions cause precipitation of Ca2+. For CaCO3, the reaction constant is Ksp is 5×10-9. Calcium carbonate then takes on H from the water to create carbonic acid. Carbonate precipitates out of the liquid and can be removed and used for many purposes. At this point the carbon is sequestered in stable form.
[0100] A second embodiment is focused solely on adding bicarbonate as a nutrient for algal culture. First, CO2 is added to the source water and acidifies it driving the pH down. Then calcium oxide, calcium hydroxide, and or calcium carbonate is added to balance pH near neutral. As carbon dioxide dissolves in water, an equilibrium is established involving the carbonate ion. Acidic water dissolves calcium oxide, calcium hydroxide, and or calcium carbonate to yield Ca2+(aq)+2HCO3-(aq)
[0101] In the foregoing description, certain terms have been used for brevity, clarity, and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for description purposes herein and are intended to be broadly construed. Moreover, the embodiments of the systems and methods illustrated and described herein are by way of example, and the scope of the invention is not limited to the exact details of construction and use. Further, it will be understood by one of skill in the art that the elements of the embodiments discussed and illustrated herein can be interchanged among the embodiments, and that each embodiment is not intended as to be limited to the individual elements presented.
[0102] Having now described the invention, the construction, the operation and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby, the new and useful constructions, and reasonable equivalents thereof obvious to those skilled in the art, are set forth in the appended claims. | A system and method for remediating a body of water and collecting suspended and dissolved solids therefrom are provided. The system includes a water-impervious lining positionable in a depression in or adjacent a body of water. The lining and depression define a treatment vessel, which includes a treatment portion, an outlet portion for containing treated water, and an outflow weir between the treatment portion and the outlet portion. Water to be treated is transported from the water body to the treatment portion. An entrapment element is delivered and mixed into the transported water, the entrapment element for capturing suspended and dissolved solids in the transported water and effecting a separation between the captured solids and water cleansed therefrom. The captured solids can be removed from the treatment basin, and the cleansed water can move through a channel in the outflow weir into the outlet portion. |
This is a divisional of application Ser. No. 07/169,033 filed Mar. 16, 1988 now U.S. Pat. No. 5,652,338.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an isolated, synthetic preparation of a novel neutrophil-specific chemotactic factor (NCF), monoclonal antibodies having specific binding affinity for NCF and a clone containing the complete coding sequence for NCF.
2. State of the Art
Activated monocytes/macrophages produce various mediators that cause inflammation. Among them are chemotactic factors which cause white blood cells to migrate into inflammatory sites where these factors are released. Neutrophils, the dominant leukocytes attracted by the chemotactic factors, are believed to play a critical role in the inflammatory reactions. Such diseases as rheumatoid arthritis, idiopathic pulmonary fibrosis and certain pathological inflammatory changes in many other conditions are believed to be caused by neutrophils and/or their products. However, a specific pro-inflammatory mediator released by tissue macrophages and other cells in response to inflammatory stimuli and leading to neutrophil-rich leukocyte accumulation in host defense and disease, has not heretofore been identified and isolated.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a biologically active novel synthetic polypeptide acting as a neutrophil-specific chemotactic factor (NCF).
It is a further object of the present invention to provide a molecular clone containing the complete coding sequence for the synthesis of NCF by either prokaryotic or eukaryotic expression vectors.
It is a still further object of the present invention to provide monoclonal antibodies having specific binding affinity for NCF of the present invention.
It is another object of the present invention to provide a kit comprising a container containing the cDNA for NCF quantitation, detection or localization of NCF mRNA in a body sample.
It is yet another object of the present invention to provide a kit comprising a container containing anti-NCF antibodies having specific binding affinity for NCF for quantitation, detection or localization of NCF in a body sample.
Other objects and advantages will become evident from the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, features and many of the attendant advantages of the invention will be better understood upon a reading of the following detailed description when considered in connection with the accompanying drawings wherein:
FIG. 1 demonstrates translation of cDNA into NCF protein in reticulocyte lysate system; and
FIGS. 2 a - 2 d shows:
(a) Northern blot analysis of mRNA induction in lipopolysaccharide (LPS) stimulated peripheral blood mononuclear cells (PBMC);
(b) The time course of the accumulation of neutrophil chemotactic activity in culture media of PBMC after stimulation with LPS;
(c) Induction of NCF mRNA in PBMC by IL-1 or TNF, but not by IL-2, gamma-IFN, and alpha-IFN;
(d) HPLC gel filtration analysis of IL-1 and TNF induced neutrophil chemotactic activity.
DETAILED DESCRIPTION OF THE INVENTION
The above and various other objects and advantages of the present invention are achieved by a homogeneously pure, isolated, synthetic neutrophil chemotactic protein, designated herein NCF, composed in the whole or in part only of the following amino acid sequence (single letter code):
NH 2 -S-A-K-E-L-R-C-Q-C-I-K-T-Y-S-K-P-F-H-P-K-F-I-K-E-L-R-V-I—E-S-G-P-H-C-A-N-T-E-I-I-V-K-L-S-D-G-R-E-L-C-L-D-P-K-E-N-W—V-Q-R-V-V-E-K-F-L-K-R-A-E-N-S.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned hereunder are incorporated herein by reference. Unless mentioned otherwise, the techniques employed herein are standard methodologies well known to one of ordinary skill in the art.
Chemical synthesis of the NCF of the present invention composed of the 72 amino acid residues as shown above, is achieved by commercially available polypeptide synthesizers. Alternatively, the NCF of the present invention is synthesized by standard techniques employing an expression vector containing in its genome the cloned complete coding sequence of NCF. Anti-NCF monoclonal antibodies of the present invention are prepared by standard hybridoma technology and utilized for purification and assaying purposes following standard immunological methodologies well known in the art.
High performance liquid chromatography (HPLC), in situ hybridization assays, Northern blotting analysis and the like are typical examples of the standard conventional techniques well known to one or ordinary skill in the art, which can be employed for isolation, localization, differentiation, detection, or measurement of the mRNA for NCF in biological samples.
It should be noted that the fact that chemically synthesized polypeptide of the present invention at 10 nanomolar concentrations acts as a neutrophil attracting factor, is shown by the results presented in Table 1.
TABLE 1
Chemotactic response of human neutrophils to
chemically synthesized NCF.
Percentage of assay
Concentration of
neutrophils that
NCF, nanomolar
migrated
1000
23
100
34
10
32
1
5
0.1
1
Hanks medium
0.3
10- 7 M fMet-Leu-Phe
40
1. It is typical for chemotactic dose-response curves to show an optimum, with a decreased response at concentrations above the optimum.
2. fMet-Leu-Phe is a commonly used reference chemoattractant.
It may be pointed out that various stimuli cause the release or secretion of more than one chemoattractant. Without the cDNA of the present invention, it is clear, of course, that the presence, specifically of the mRNA for NCF as an involved factor in a particular clinico-pathological situation, could not be definitively identified and diagnosed. cDNA of the present invention due to its binding affinity for mRNA for NCF, for the first time makes it possible to analyze body samples such as joint fluid, sputum, alveolar lavage fluid, tissue samples and the like to detect the presence or absence of mRNA for NCF. Of course, the antibodies can also be utilized for diagnostic purposes to detect the NCF and to neutralize the NCF for alleviating any disease or anomalous conditions in which the presence of NCF is found to be a causative factor.
A pharmaceutical composition for use in treating inflammatory condition comprises an anti-inflammatory effective amount of the anti-NCF monoclonal antibodies in pharmaceutically acceptable carrier, such as physiological saline, sterile non-toxic buffer and the like.
A deposit of cDNA for NCF and of the hybridoma for anti-NCF monoclonal antibodies have been made at the ATCC, Manassas, Va. on Jan. 12, 1988 and Feb. 17, 1988, respectively, under the accession numbers 40412 and HB9647, respectively. The deposits shall be viably maintained, replacing if they became non-viable, for a period of 30 years from the date of the deposit, or for 5 years from the last data of request for a sample of the deposit, whichever is longer, and made available to the public without restriction in accordance with the provisions of the law. The Commissioner of Patents and Trademarks, upon request, shall have access to the deposits.
It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.
1
1560 BASE PAIRS
NUCLEIC ACID
UNKNOWN
UNKNOWN
1
CTCCATAAGG CACAAACTTT CAGAGACAGC AGAGCACACA 40
AGCTTCTAGG ACAAGAGCCA GGAAGAAACC ACCGGAAGGA 80
ACCATCTCAC TGTGTGTAAA CATGACTTCC AAGCTGGCCG 120
TGGCTCTCTT GGCAGCCTTC CTGATTTCTG CAGCTCTGTG 160
TGAAGGTGCA GTTTTGCCAA GG AGT GCT AAA GAA CTT 197
AGA TGT CAG TGC ATA AAG ACA TAC TCC AAA CCT TTC 233
CAC CCC AAA TTT ATC AAA GAA CTG AGA GTG ATT GAG 269
AGT GGA CCA CAC TGC GCC AAC ACA GAA ATT ATT GTA 305
AAG CTT TCT GAT GGA AGA GAG CTC TGT CTG GAC CCC 341
AAG GAA AAC TGG GTG CAG AGG GTT GTG GAG AAG TTT 377
TTG AAG AGG GCT GAG AAT TCA TAAAAAAATT CATTCTCTGT 418
GGTATCCAAG AATCAGTGAA GATGCCAGTG AAACTTCAAG 458
CAAATCTACT TCAACACTTC ATGTATTGTG TGGGTCTGTT 498
GTAGGGTTGC CAGATGCAAT ACAAGATTCC TGGTTAAATT 538
TGAATTTCAG TAAACAATGA ATAGTTTTTC ATTGTACCAT 578
GAAATATCCA GAACATACTT ATATGTAAAG TATTATTTAT 618
TTGAATCTAC AAAAAACAAC AAATAATTTT TAAATATAAG 658
GATTTTCCTA GATATTGCAC GGGAGAATAT ACAAATAGCA 698
AAATTGGGCC AAGGGCCAAG AGAATATCCG AACTTTAATT 738
TCAGGAATTG AATGGGTTTG CTAGAATGTG ATATTTGAAG 778
CATCACATAA AAATGATGGG ACAATAAATT TTGCCATAAA 818
GTCAAATTTA GCTGGAAATC CTGGATTTTT TTCTGTTAAA 858
TCTGGCAACC CTAGTCTGCT AGCCAGGATC CACAAGTCCT 898
TGTTCCACTG TGCCTTGGTT TCTCCTTTAT TTCTAAGTGG 938
AAAAAGTATT AGCCACCATC TTACCTCACA GTGATGTTGT 978
GAGGACATGT GGAAGCACTT TAAGTTTTTT CATCATAACA 1018
TAAATTATTT TCAAGTGTAA CTTATTAACC TATTTATTAT 1058
TTATGTATTT ATTTAAGCAT CAAATATTTG TGCAAGAATT 1098
TGGAAAAATA GAAGATGAAT CATTGATTGA ATAGTTATAA 1138
AGATGTTATA GTAAATTTAT TTTATTTTAG ATATTAAATG 1178
ATGTTTTATT AGATAAATTT CAATCAGGGT TTTTAGATTA 1218
AACAAACAAA CAATTGGGTA CCCAGTTAAA TTTTCATTTC 1258
AGATATACAA CAAATAATTT TTTAGTATAA GTACATTATT 1298
GTTTATCTGA AATTTTAATT GAACTAACAA TCCTAGTTTG 1338
ATACTCCCAG TCTTGTCATT GCCAGCTGTG TTGGTAGTGC 1378
TGTGTTGAAT TACGGAATAA TGAGTTAGAA CTATTAAAAC 1418
AGCCAAAACT CCACAGTCAA TATTAGTAAT TTCTTGCTGG 1458
TTGAAACTTG TTTATTATGT ACAAATAGAT TCTTATAATA 1498
TTATTTAAAT GACTGCATTT TTAAATACAA GGCTTTATAT 1538
TTTTAACTTT AAAAAAAACC GG 1560 | An isolated, synthetic preparation of a novel neutrophil-specific chemotactic factor (NCF), monoclonal antibodies having specific binding affinity of NCF and a clone containing the complete cDNA coding sequence for NCF are disclosed. |
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates generally to dispensing of small portions of thin webs from rolls by pulling and tearing, and more specifically to an adapter configured to be fitted onto conventional dispensing boxes to improve their dispensing action.
2. Description of the Prior Art
Devices for the dispensing of small portions of sheet material from rolls of indeterminant length are, of course, well known and have a long history of developement. A significant number of U.S. Patents teach methods and apparatus to accomplish a wide variety of dispensing actions, and are reflective of the amount of effort which have been put into this area over the years. For example, U.S. Pat. No. 2,334,997 to Doll discloses one approach to the dispensing of paper products from a hand held container using a pulling and tearing action, wherein the user by hand pressure may somewhat control the pulling action, and the cutting action is accomplished against a sharp edge located along one extremity of a triangular shaped box.
In another U.S. Pat. No. 2,614,015 to MeGchee there is disclosed a wall mounted box, formed of two parts, which is used to dispense wax paper. A cut-out access hole through both parts is provided to allow the user to insert a finger and coax out the next portion of web to be pulled out and torn off.
Also, Canadian Pat. No. 541,507 to Finkel teaches yet another approach to controlling the pulling/tearing action of a sheet material dispenser. In this patent, we see a steel spring having a plastic/rubber coated end positioned so as to contact the web as it is pulled from between two surfaces forming a container housing the roll of material. The spring loaded coated end is angled so as to exert a type of ratchet action on the web being dispensed to overcome possible roll recoil action.
Due to the increasing availability of, and continuous demand for, disposable household products such as wax paper, plastic wrap, and the like, an entire industry has emerged to produce the containers and dispensers needed to carry these products. Lacking any industry-wide standards, the resulting dispensing boxes of the tear-off type include a bewildering array of approaches to the manipulative tasks which must be mastered to beneficially use the products being dispensed. Many of the existing boxes represent difficult puzzles to the users as they try to operate them; while others pose safety hazards as novice fingers attempt to work in close proximity to the sharp cutting edges which may be positioned in entirely unexpected or out of view places. These puzzles include the steps of; initially opening the dispensing box and removing the first portion of the web; arranging the web ends for property tearing against a possibly as yet unknown tearing edge; and deftly controlling the pulling rate while preventing unwanted recoil after the desired length of web is pulled and torn.
Many of these difficulties are, however, largely the result of a lack of user familiarity with the particular techniques needed to manipulate a particular dispensing box--which technique may not be appropriate to the very next dispensing box which the user is called on to handle. Therefore, it is clear that a need exists for a dispensing aid which will mitigate these difficulties, and which will provide the user with a straight-forward device which allows a single, well known, and well controlled dispensing technique to be applied to the wide range of dispensing boxes in existence. The improved dispenser adapter taught in the present invention admirably meets this need.
SUMMARY OF THE INVENTION
It is therefore a primary object of the present invention to provide an improved dispenser adapter for use with existing dispensing boxes of the pull and tear type; and one which will overcome the disadvantages of the prior art devices.
A further object of the prsent invention is to provide an improved dispenser adapter which may be fitted over existing dispensing boxes and which cooperates with the box structure to provide a single, safe, and controllable pulling/tearing action, thereby greatly aiding in the dispensing of small sections of thin webs.
A yet further object of the present invention is to provide a highly controllable, spring loaded, force producing element within the improved dispenser adapter to allow the user to positively control the friction applied to the web within the dispensing box.
A yet further object of the present invention is to provide this highly controllable force via a range of spring types and configurations, including metal springs and springs implemented using predetermined volumes of resilient materials such as plastic foam, such that the spring's dynamic properties and not merely the manual dexterity of the user exert these controllable forces.
A still further object of the present invention is to provide an improved dispensing unit comprising an improved dispenser adapter of the types recited above in combination with a dispensing box such that a wide range of household or industrial webs may be dispensed using a single and easily mastered dispensing action.
By means of a number of illustrative, preferred, and alternate embodiments, the present disclosure teaches the broad principles of an improved dispensing technique wherein the user can apply easily controllable friction action to the webs being dispensed, and both proportional and on/off braking action is applied to the web via the particular spring structures disclosed. Both metal and resilient material springs are employed, and a wide range of spring distributions are employed to produce a desired array of forces which allow the dispensing action to be accomplished, resulting in a hetertofore unavailable safe and effective dispensing technique.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional objects and advantages of the invention will become apparent to those skilled in the art as the description proceeds with reference to the accompanying drawings wherein:
FIG. 1 is a perspective view of an improved dispenser adapter according to the present invention;
FIG. 2 is a perspective view of the improved dispenser adapter positioned above a conventional dispensing box with which it may be associated;
FIG. 3A is a simplified transverse cross sectional view of the conventional dispensing box;
FIG. 3B is a simplified transverse cross sectional view of the improved adapted;
FIG. 3C is a simplified transverse cross sectional view of the improved adapter fitted onto an idealized dispenser box;
FIGS. 4A and 4B are simplified transverse and longitudinal cross sectional views respectively of a preferred metal spring embodiment used with the improved adapter;
FIGS. 5A and 5B are simplified transverse and longitudinal cross sectional views respectively of an alternate embodiment of the improved adapter employing resilient materials in lieu of the metal spring elements;
FIGS. 6A and 6B are simplified transverse and longitudinal cross sectional views respectively of a further alternate embodiment of the improved adapter employing resilient materials; and
FIGS. 7A and 7B are simplified transverse and longitudinal cross sectional views respectively of the improved adapter employing a single piece spring element.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, there is shown a perspective view of an illustrative dispenser adapter according to the present invention. The adapter 10 is shown in use as being positioned over a conventional household wrap dispenser box 12, the combination of which greatly facilitates the dispensing of plastic wrap 14. By way of a brief overview, the adapter 10 is formed as a five sided, open bottomed covering device, rectangular in cross section and sized to fit snugly over existing dispenser boxes. In particular, the adapter 10 comprises a top 16, front and back elongated sides 18F and 18B, two end sections 20L and 20R, and may be made from a variety of materials. Illustrative materials include cardboard, plastics, sheet metal, and similar thin sheet materials which are amenable to low cost fabrication techniques such as dye cutting; folding and gluing; injection molding; and stamp forming. The lower rim of front side 18F includes a serrated cutting edge 22. The cutting edge 22 may be formed as an integral part of the material used for the adapter 10 when stiff materials are used, or alternately may be formed of a separate strip of rigid material and affixed to the lower rim of the front side 18F. Shown in phantom lines within the end piece 20L are a number of additional elements which are described in detail below. These include a supply roll of web 14', and a spring element 26.
While the illustrative and alternate embodiments described herein specifically recite the dispensing of household plastic wrap, it is clear that the methods and apparatus of the present invention are equally applicable to the dispensing of a wide range of roll products. Within this range, typical household products would include wax paper, aluminum foil, paper towels, and the like; and typical industrial products would include electrical insulating wrap, impregnated papers/fabrics, and the like. To aid in subsequent drawings and descriptions, a longitudinal axis of the adapter 10 is defined as being parallel to the line containing the serrated cutting edge 22; and a transverse plane is defined as orthogonal to that axis--that is, any plane parallel to either end 20 for 20R.
In FIG. 2, the dispenser adaptor 10 is shown lifted from its associated box 12, and both articles are shown in partially fragmented form to illustrate selected internal components. Within the upper portion of the adapter 10 is a pressure plate 24 which is affixed to a pair of spring elements 26L and 26R via suitable attachment means 28. The dispenser box 12 may be of conventional construction, but is shown advantageously as having a first top portion 30 which is carried by a back side 32B, which in turn is connected to a bottom 34. With brief reference to FIG. 3A, in addition to FIG. 2, a simplified cross sectional view of the box 12 will clarify the remaining box elements. A second top portion 36 is carried by a front side 32F, the two top portions being substantially parallel and including a gap 38 through which the plastic wrap 14, or other web, is passed. The box 12 further has ends 40L and 40R and is typically made of light to medium weight paperboard so that its various surfaces are somewhat flexible.
A simplified cross sectional view of the adapter 10 is shown in FIG. 3B, and a simplified cross sectional view of the adapter 10 positioned over an idealized box 12 is shown in FIG. 3C. The
relative sizes of the various elements throughout the various drawings are, of course, not strictly to scale. Throughout the present description, the letters designating front or back, "F" or "B", and the like, will be omitted from the description of views where this orientation /position information is not needed. In FIG. 3B, the spring 26 is substantially relaxed and the pressure plate 24 assumes a non inserted "at rest" position within the adapter 10. In FIG. 3C, the adapter 10 is positioned over the box 12 such that the pressure plate 24 bears against the top of the idealized box 12 under the urging of the partially compressed spring 26. Typically, the adapter 10 will fit over the box 12 to a depth of about three quarters of the height of sides 32 when in the inserted "at rest" position; and will cover slightly more when the user applies squeezing forces. Note that as the spring 26 is compressed, its outer ends are urged outwards, approaching closer to the front and back sides 18F and 18B. In use, when this pressure plate 24 is caused to bear against the two top portions 30 and 36, that action will tend to close the gap 38 and will tend to brake any movement of the wrap 14. This braking action--shown as generated by the pair of forces F and F' in FIG. 1--may be controlled by the user to produce a proportional effect. Thus, a slight squeezing by the user's fingers applies a light force through the gap 38 which applies a slight frictional loading on the wrap. This loading produces a slight resistance to the pulling action--shown as generated by the pulling force P in FIG. 1--which both brakes the web movement and reduces the rolling action which is imparted to the roll of material 14' remaining in the box 12. So the wrap 14 slows down, and the roll of material 14' comes virtually to a stop under the friction of its own weight.
When the desired amount of wrap 14 has been dispensed, the user simply increases the forces F--F' by squeezing firmer and fully stops the web movement permitting the wrap 14 to be torn off along the serrated edge 22. During this tearing step, the roll of material 14' is fully braked by virtue of the firm squeezing and is effectively decoupled from any external additional pulling force, as well as from any internal recoil forces tending to retract the web end back into the box 12. Also, the location of the cutting edge 22 removes any necessity for finger contact during these steps, resulting in a very safe overall action.
Referring to FIGS. 4A and 4B, there are shown simplified transverse and longitudinal cross sectional views respectively of a preferred spring embodiment used to implement an improved adapter 10'. FIG. 4A depicts an adapter similar to that of FIG. 3B except that the depth "d" of the pressure plate 24' is less than that of the pressure plate 24 of FIG. 3B. While either depth will provide the desired urging action against the top elements of an associated box 12, the narrower dimension of plate 24' may be useful for a wider range of box configurations due to its more centrally restricted pressure area. During use, the pressure plate 24' may experience vertical travel to an extent approximated by the dimension "T".
In the longitudinal view of FIG. 4B there is shown retaining means 42 which may be used to hold the plate 24' attached to the adapter 10'. This retaining means may take a number of forms, such as a simple length of thread or ribbon attached at points 43 and 45, or may in some embodiments be omitted entirely. In either event, the springs 26 are the only significant elements for determining the amount of pressure applied to the top elements of any associated box 12 in response to the user of applied forces F and F'. This is accomplished by suitably controlling the various spring constants such that a very specific amount of pressure is exerted by them; and further by devising the spring structure such that specific amounts of pressure are exerted over a predetermined distance of travel (in compression) "T". These dynamic characteristics are readily achieved by the use of well known spring steel materials, and by well known spring fabrication techniques. Additionally, by suitable selection of the number of springs 26 used, their relative replacement, and the properties of the pressure plate 24', a desired longitudinal distribution of forces "f" may be readily achieved. In addition to left and right springs 26L and 26R, a spring 26M, attached by means attachment 28, is shown as positioned at the middle of the plate 24' to accomplish this desired distribution. Clearly, Other numbers of springs and other spring positions along the length of pressure plate 24' are also contemplated.
Thus far there has been described basic and preferred embodiments of an improved adapter 10 (and 10') which provide new and improved operating modes by virtue of the controllable array of forces "f" which may be exerted to greatly improve the dispensing of webs. These embodiments teach simple structures for exerting the desired magnitudes and spatial distributions of forces along the longitudinal and transverse axes, and for exerting this array of forces for the desired distance of travel. The significance of these new operating modes is that they allow for both proportional and "bang-bang" braking action of the webs being dispensed without dependence of the spring properties (or lack of same, or the aging of same) of the materials actually used to fabricate the outer shells of either the adapter 10 or the box 12. Also significant is that these new operating modes are achieved without requiring any undue amount of manual dexterity by the user.
Referring now to FIGS. 5A and 5B, there is shown an alternate embodiment of the improved adapter 10' (designated as 10") wherein the metal springs 26 have been replaced by resilient material sections 44. Any one of a number of low cost resilient materials in the plastic foam family may be used to provide the above described dynamic spring action. As with FIG. 4B, FIG. 5B shows the use of three elements, including a left resilient member 44L, a middle resilient member 44M, and a right resilient member 44R. The resilient members 44 are attached to the top 16 and pressure plate 24 by layers of adhesive 46 and 48 (as shown best in FIG. 5A), and therefore the retaining means 42 of FIG. 4B is not required. The array of distributed forces "f" produced by the embodiment of adapter 10" are substantially the same as for the discrete metal spring embodiment previously described.
A further alternate embodiment employing resilient materials is shown in FIGS. 6A and 6B wherein the combination of discrete resilient members and a single pressure plate is replaced by a one piece resilient member 50. This embodiment is designated as improved adapter 9 and includes the resilient member 50 having a depth "d", about the same size as that of FIG. 4A, and a longitudinal length (not designated by a symbol), about the same as that of FIG. 4B. The member 50 is affixed to the adapter 9 by a layer of adhesive 46. As distinct from the previous embodiments, the array of distributed forces "f*" produced may be shaped as a result of varying the vertical dimension of the resilient member 50 along its longitudinal length. This is shown as the symmetrical difference in thicknesses indicated by the dimensions "H" greater than "h" in FIG. 6B.
Also contemplated within the range of embodiments according to the present invention is the substitution of the multiple spring 26 by a single piece spring element 26S as shown in FIGS. 7A and 7B. The spring 26S is shown as attached to the pressure plate 24' by attachment means 28 (illustratively, two are shown), and retaining means previously described may or may not be included. As with the previously described embodiments of FIGS. 4A and 4B, the various spring constants of the single spring 26S are suitably chosen to produce the desired array of forces "f" along its longitudinal axis responsive to the user applied forces F--F'.
Although the invention has been described in terms of selected preferred embodiments, the invention should not be deemed limited thereto, since other embodiments and modifications will readily occur to one skilled in the art. One such modification would be the combining of any of the various adapter embodiments described above with a mating dispensing box to form a complete dispensing unit--in lieu of a dispensing adapter. To implement this modification a dispensing box of the type depicted in part in FIG. 3A would be combined with an adapter of the type depicted in part in FIG. 3B. Various kinds of interconnection means may be employed to retain the box and adapter shells together, such as: mating male/female indentations formed into corresponding end sections; interlocking or projecting tabs formed into corresponding sides; or adhesively attached retaining means of the general type described in connection with the embodiment of FIG. 4B. It is therefore to be understood that the appended claims are intended to cover all such modifications as fall within the true spirit and scope of the invention. | A dispenser adapter to improve the dispensing of thin webs from rolls of material contained in conventional dispensing boxes is specially configured to provide its benefits of antirecoil and risk free tearing to a wide range of dispensing boxes. The adapter is particularly suited to being retrofitted to commercially available dispensing boxes containing a wide range of materials such as plastic wrap, aluminum foil, and wax paper, while allowing the user to dispense these various materials by a single consistent, positively controlled, feeding and tearing action. In a preferred embodiment, a pressure plate loaded by one or more metal springs allows the user to easily exert a proportional braking action, and alternate embodiments teach the use of low cost resilient materials in various arrangements to provide the desired dynamic spring action. Additionally, a complete dispensing unit is disclosed which incorporates the teachings of the improved adapter. |
BACKGROUND OF INFORMATION
[0001] The present invention relates to magnetic hard disk drives. More specifically, the present invention relates to a system and method for preventing piezoelectric micro-actuator manufacturing and operational imperfections.
[0002] In the art today, different methods are utilized to improve recording density of hard disk drives. FIG. 1 provides an illustration of a typical drive arm configured to read from and write to a magnetic hard disk. Typically, voice-coil motors (VCM) 102 are used for controlling a hard drive's arm 104 motion across a magnetic hard disk 106 . Because of the inherent tolerance (dynamic play) that exists in the placement of a recording head 108 by a VCM 102 alone, micro-actuators 110 are now being utilized to ‘fine-tune’ head 108 placement, as is described in U.S. Pat. No. 6,198,606. A VCM 102 is utilized for course adjustment and the micro-actuator then corrects the placement on a much smaller scale to compensate for the VCM's 102 (with the arm 104 ) tolerance. This enables a smaller recordable track width, increasing the ‘tracks per inch’ (TPI) value of the hard drive (increased drive density).
[0003] [0003]FIG. 2 provides an illustration of a micro-actuator as used in the art. Typically, a slider 202 (containing a read/write magnetic head; not shown) is utilized for maintaining a prescribed flying height above the disk surface 106 (See FIG. 1). Micro-actuators may have flexible beams 204 connecting a support device 206 to a slider containment unit 208 enabling slider 202 motion independent of the drive arm 104 (See FIG. 1). An electromagnetic assembly or an electromagnetic/ferromagnetic assembly (not shown) may be utilized to provide minute adjustments in orientation/location of the slider/head 202 with respect to the arm 104 (See FIG. 1).
[0004] Utilizing actuation means such as piezoelectrics (see FIG. 3), problems such as electrical sparking and particulate-enabled shortage can exist. It is therefore desirable to have a system for component treatment that prevents the above-mentioned problems in addition to having other benefits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] [0005]FIG. 1 provides an illustration of a drive arm configured to read from and write to a magnetic hard disk as used in the art.
[0006] [0006]FIG. 2 provides an illustration of a micro-actuator as used in the art.
[0007] [0007]FIG. 3 provides an illustration of a ‘U’-shaped micro-actuator utilizing multi-layered piezoelectric transducers (PZT) to provide slider actuation.
[0008] [0008]FIG. 4 illustrates a potential problem of particulate-enabled shorting between piezoelectric layers.
[0009] [0009]FIG. 5 illustrates various problems affecting PZT performance.
[0010] [0010]FIG. 6 provides a cross-section of the micro-actuator arms with the micro-actuators unseparated and a cross-section of a micro-actuator arm after micro-actuator separation.
[0011] [0011]FIG. 7 provides a cross-section of the micro-actuator arms with the micro-actuators unseparated and a cross-section of a micro-actuator arm after micro-actuator separation under principles of the present invention.
DETAILED DESCRIPTION
[0012] [0012]FIG. 3 provides an illustration of a ‘U’-shaped micro-actuator utilizing multi-layered piezoelectric transducers (PZT) to provide slider actuation. A slider (not shown) is attached between two arms 302 , 304 of the micro-actuator 301 at two connection points 306 , 308 . Layers 310 of PZT material, such as a piezoelectric ceramic material like lead zirconate titanate, are bonded to the outside of each arm (actuator finger) 302 , 304 . PZT material has an anisotropic structure whereby the charge separation between the positive and negative ions provides for electric dipole behavior. When a potential is applied across a poled piezoelectric material, Weiss domains increase their alignment proportional to the voltage, resulting in structural deformation (i.e. regional expansion/contraction) of the PZT material. As the PZT structures 310 bend (in unison), the arms 302 , 304 (which are bonded to the PZT structures 310 ), bend also, causing the slider (not shown) to adjust its position in relation to the micro-actuator 301 (for magnetic head fine adjustments).
[0013] [0013]FIG. 4 demonstrates a potential problem of particulate-enabled shorting between piezoelectric layers. During manufacture and/or drive operation, particles may be deposited, and particle(s) 404 may end up bridging conductive layers 406 . Relative humidity can cause the particle(s) to absorb moisture from the air, enabling electrical conduction between PZT layers. This short 404 in the piezoelectric structure 406 can prevent its normal operation, adversely affecting micro-actuator 402 performance.
[0014] [0014]FIG. 5 illustrates various problems affecting PZT performance. FIG. 5 a provides an image of a stray particle 504 bridging (and potentially shorting) piezoelectric layers 502 . As stated above, humidity can cause the particle 504 to absorb moisture and become electrically conductive. FIG. 5 b provides an image of damage caused by electrical arcing 506 between piezoelectric layers 508 . Under the right conditions of voltage and air humidity, electricity may arc between piezoelectric layers 508 , causing damage and deformation 506 . FIG. 5 c provides an image of ‘smearing’ 510 (and potentially shorting) between layers 512 . Smearing can occur during manufacture when the micro-actuators are cut for separation. (See FIGS. 6 and 7). Material of the different layers 512 is smeared across one another as the cutting tool passes over the surface exposed by cutting.
[0015] [0015]FIG. 6 provides a cross-section of the micro-actuator arms with the micro-actuators unseparated and a cross-section of a micro-actuator arm after micro-actuator separation. FIG. 6 a illustrates a cross-section 604 of a portion 602 of a micro-actuator block structure. The cross-section 604 illustrates alternating layers 628 of conductive material 622 and PZT (insulating) material 624 applied to the micro-actuator. FIG. 6 b illustrates a cross-section 608 of a micro-actuator arm 606 after separating the micro-actuator 610 from others. Separation may be performed in one embodiment by mechanical means (e.g., a rotating wheel blade or a straight edge knife). Other embodiments involve electrical means for micro-actuator separation (e.g., electric sputtering or ion milling). Further, chemical means may be used (e.g., chemical vapor deposition (CVD)). Note that the sides of the micro-actuator arm (finger) 606 expose the piezoelectric layers, including the electrically-conductive layers 622 .
[0016] [0016]FIG. 7 provides a cross-section of the micro-actuator arms with the microactuators unseparated and a cross-section of a micro-actuator arm after micro-actuator separation and ending with conductive layer application under principles of the present invention. FIG. 7 a illustrates a cross-section 704 of a portion 702 of a micro-actuator block structure. FIG. 7 b illustrates a cross-section 708 of a micro-actuator arm 706 after separating the micro-actuator 710 from others. In one embodiment of the present invention, after a set of conductive strips (conductive material) 712 , such as gold, platinum or copper, are placed upon the micro-actuator arm 706 , a PZT layer (insulative layer) 714 is applied over and between the conductive strips 712 , physically and electrically isolating the conductive strips 712 . Another set of conductive strips 712 and a PZT layer 714 are applied and the process is repeated until the number of layers and/or thickness is appropriate for the micro-actuator's application and performance. In one embodiment, the last layer applied is the conductive strip 712 , followed by the placement of a bonding pad 716 upon the piezoelectric layers (and on opposite ends 717 of the micro-actuator finger 706 , see also FIG. 9). In one embodiment, four to six layers PZT layers are utilized (five to seven conductive layers).
[0017] In one embodiment, upon separation of the micro-actuators 710 , the PZT layers 714 physically isolate the conductive strips 712 from each other, and thus, prevent ‘smearing’ (and potential shorting). Further, the PZT layers 714 electrically insulate the sides of the piezoelectric layers, preventing ‘arcing’ damage and particulate contamination (electrical bridging/shorting).
[0018] [0018]FIG. 8 provides a cross-section of the micro-actuator arms with the micro-actuators unseparated and a cross-section of a micro-actuator arm after micro-actuator separation and ending with PZT layer application under principles of the present invention. FIG. 8 a illustrates a cross-section 804 of a portion 802 of a micro-actuator block structure. FIG. 8 b illustrates a cross-section 808 of a micro-actuator arm 806 after separating the micro-actuator 810 from others. In one embodiment of the present invention, after a set of conductive strips (conductive material) 812 , such as gold, platinum or copper, are placed upon the micro-actuator arm 806 , a PZT layer (insulative layer) 814 is applied over and between the conductive strips 812 , physically and electrically isolating the conductive strips 812 . Another set of conductive strips 812 and a PZT layer 814 are applied and the process is repeated until the number of layers and/or thickness is appropriate for the micro-actuator's application and performance. In one embodiment, the last layer applied is a PZT layer 815 . In one embodiment, the last PZT layer 815 provides a ‘window’ (gap in insulation) for the bonding pad 816 to be attached within. (See FIG. 8). In one embodiment, four to six PZT layers and four to six conductive layers are utilized.
[0019] In one embodiment, upon separation of the micro-actuators 810 , the PZT layers 814 , 815 physically isolate the conductive strips 812 from each other, and thus, prevent ‘smearing’ (and potential shorting). Further, the PZT layers 814 , 815 electrically insulate the sides of the piezoelectric layers, preventing ‘arcing’ damage and particulate contamination (electrical bridging/shorting).
[0020] [0020]FIG. 9 provides a cross-section of a finger of a micro-actuator under principles of the present invention. In an embodiment, a window 902 is provided in the last PZT layer of 915 to give a conduction path between the top conductive layer (strip) 904 and the bonding pad 906 .
[0021] Although several embodiments are specifically illustrated and described herein, it will be appreciated that modifications and variations of the present invention are covered by the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention. | A system and method for preventing operational and manufacturing imperfections in piezoelectric micro-actuators by physically and electrically isolating conductive layers of the piezoelectric material. |
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application is a division of U.S. patent application Ser. No. 09/821,240, filed on Mar. 29, 2001, now U.S. Pat. No. 6,357,107, which is a division of U.S. patent application Ser. No. 09/350,601, filed on Jul. 9, 1999, now issued as U.S. Pat. No. 6,240,622, the specifications of which are incorporated herein by reference.
FIELD OF THE INVENTION
This invention relates to inductors, and more particularly, it relates to inductors used with integrated circuits.
BACKGROUND OF THE INVENTION
Inductors are used in a wide range of signal processing systems and circuits. For example, inductors are used in communication systems, radar systems, television systems, highpass filters, tank circuits, and butterworth filters.
As electronic signal processing systems have become more highly integrated and miniaturized, effectively signal processing systems on a chip, system engineers have sought to eliminate the use of large, auxiliary components, such as inductors. When unable to eliminate inductors in their designs, engineers have sought ways to reduce the size of the inductors that they do use.
Simulating inductors using active circuits, which are easily miniaturized, is one approach to eliminating the use of actual inductors in signal processing systems. Unfortunately, simulated inductor circuits tend to exhibit high parasitic effects, and often generate more noise than circuits constructed using actual inductors.
Inductors are miniaturized for use in compact communication systems, such as cell phones and modems, by fabricating spiral inductors on the same substrate as the integrated circuit to which they are coupled using integrated circuit manufacturing techniques. Unfortunately, spiral inductors take up a disproportionately large share of the available surface area on an integrated circuit substrate.
For these and other reasons there is a need for the present invention.
SUMMARY OF THE INVENTION
The above mentioned problems and other problems are addressed by the present invention and will be understood by one skilled in the art upon reading and studying the following specification. An integrated circuit inductor compatible with integrated circuit manufacturing techniques is disclosed.
In one embodiment, an inductor capable of being fabricated from a plurality of conductive segments and interwoven with a substrate is disclosed. In an alternate embodiment, a sense coil capable of measuring the magnetic field or flux produced by an inductor comprised of a plurality of conductive segments and fabricated on the same substrate as the inductor is disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a cutaway view of some embodiments of an inductor of the present invention.
FIG. 1B is a top view of some embodiments of the inductor of FIG. 1 A.
FIG. 1C is a side view of some embodiments of the inductor of FIG. 1 A.
FIG. 2 is a cross-sectional side view of some embodiments of a highly conductive path including encapsulated magnetic material layers.
FIG. 3A is a perspective view of some embodiments of an inductor and a spiral sense inductor of the present invention.
FIG. 3B is a perspective view of some embodiments of an inductor and a nonspiral sense inductor of the present invention.
FIG. 4 is a cutaway perspective view of some embodiments of a triangular coil inductor of the present invention.
FIG. 5 is a top view of some embodiments of an inductor coupled circuit of the present invention.
FIG. 6 is diagram of a drill and a laser for perforating a substrate.
FIG. 7 is a block diagram of a computer system in which embodiments of the present invention can be practiced.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.
FIG. 1A is a cutaway view of some embodiments of inductor 100 of the present invention. Inductor 100 includes substrate 103 , a plurality of conductive segments 106 , a plurality of conductive segments 109 , and magnetic film layers 112 and 113 . The plurality of conductive segments 109 interconnect the plurality of conductive segments 106 to form highly conductive path 114 interwoven with substrate 103 . Magnetic film layers 112 and 113 are formed on substrate 103 in core area 115 of highly conductive path 114 .
Substrate 103 provides the structure in which highly conductive path 114 that constitutes an inductive coil is interwoven. Substrate 103 , in one embodiment, is fabricated from a crystalline material. In another embodiment, substrate 103 is fabricated from a single element doped or undoped semiconductor material, such as silicon or germanium. Alternatively, substrate 103 is fabricated from gallium arsenide, silicon carbide, or a partially magnetic material having a crystalline or amorphous structure. Substrate 103 is not limited to a single layer substrate. Multiple layer substrates, coated or partially coated substrates, and substrates having a plurality of coated surfaces are all suitable for use in connection with the present invention. The coatings include insulators, ferromagnetic materials, and magnetic oxides. Insulators protect the inductive coil and separate the electrically conductive inductive coil from other conductors, such as signal carrying circuit lines. Coatings and films of ferromagnetic materials, such as magnetic metals, alloys, and oxides, increase the inductance of the inductive coil.
Substrate 103 has a plurality of surfaces 118 . The plurality of surfaces 118 is not limited to oblique surfaces. In one embodiment, at least two of the plurality of surfaces 118 are parallel. In an alternate embodiment, a first pair of parallel surfaces are substantially perpendicular to a second pair of surfaces. In still another embodiment, the surfaces are planarized. Since most integrated circuit manufacturing processes are designed to work with substrates having a pair of relatively flat or planarized parallel surfaces, the use of parallel surfaces simplifies the manufacturing process for forming highly conductive path 114 of inductor 100 .
Substrate 103 has a plurality of holes, perforations, or other substrate subtending paths 121 that can be filled, plugged, partially filed, partially plugged, or lined with a conducting material. In FIG. 1A , substrate subtending paths 121 are filled by the plurality of conducting segments 106 . The shape of the perforations, holes, or other substrate subtending paths 121 is not limited to a particular shape. Circular, square, rectangular, and triangular shapes are all suitable for use in connection with the present invention. The plurality of holes, perforations, or other substrate subtending paths 121 , in one embodiment, are substantially parallel to each other and substantially perpendicular to substantially parallel surfaces of the substrate.
Highly conductive path 114 is interwoven with a single layer substrate or a multilayer substrate, such as substrate 103 in combination with magnetic film layers 112 and 113 , to form an inductive element that is at least partially embedded in the substrate. If the surface of the substrate is coated, for example with magnetic film 112 , then conductive path 114 is located at least partially above the coating, pierces the coated substrate, and is interlaced with the coated substrate.
Highly conductive path 114 has an inductance value and is in the shape of a coil. The shape of each loop of the coil interlaced with the substrate is not limited to a particular geometric shape. For example, circular, square, rectangular, and triangular loops are suitable for use in connection with the present invention.
Highly conductive path 114 , in one embodiment, intersects a plurality of substantially parallel surfaces and fills a plurality of substantially parallel holes. Highly conductive path 114 is formed from a plurality of interconnected conductive segments. The conductive segments, in one embodiment, are a pair of substantially parallel rows of conductive columns interconnected by a plurality of conductive segments to form a plurality of loops.
Highly conductive path 114 , in one embodiment, is fabricated from a metal conductor, such as aluminum, copper, or gold or an alloy of a such a metal conductor. Aluminum, copper, or gold, or an alloy is used to fill or partially fill the holes, perforations, or other paths subtending the substrate to form a plurality of conductive segments. Alternatively, a conductive material may be used to plug the holes, perforations, or other paths subtending the substrate to form a plurality of conductive segments. In general, higher conductivity materials are preferred to lower conductivity materials. In one embodiment, conductive path 114 is partially diffused into the substrate or partially diffused into the crystalline structure.
For a conductive path comprised of segments, each segment, in one embodiment, is fabricated from a different conductive material. An advantage of interconnecting segments fabricated from different conductive materials to form a conductive path is that the properties of the conductive path are easily tuned through the choice of the conductive materials. For example, the internal resistance of a conductive path is increased by selecting a material having a higher resistance for a segment than the average resistance in the rest of the path. In an alternate embodiment, two different conductive materials are selected for fabricating a conductive path. In this embodiment, materials are selected based on their compatibility with the available integrated circuit manufacturing processes. For example, if it is difficult to create a barrier layer where the conductive path pierces the substrate, then the conductive segments that pierce the substrate are fabricated from aluminum. Similarly, if it is relatively easy to create a barrier layer for conductive segments that interconnect the segments that pierce the substrate, then copper is used for these segments.
Highly conductive path 114 is comprised of two types of conductive segments. The first type includes segments subtending the substrate, such as conductive segments 106 . The second type includes segments formed on a surface of the substrate, such as conductive segments 109 . The second type of segment interconnects segments of the first type to form highly conductive path 114 . The mid-segment cross-sectional profile 124 of the first type of segment is not limited to a particular shape. Circular, square, rectangular, and triangular are all shapes suitable for use in connection with the present invention. The mid-segment cross-sectional profile 127 of the second type of segment is not limited to a particular shape. In one embodiment, the mid-segment cross-sectional profile is rectangular. The coil that results from forming the highly conductive path from the conductive segments and interweaving the highly conductive path with the substrate is capable of producing a reinforcing magnetic field or flux in the substrate material occupying the core area of the coil and in any coating deposited on the surfaces of the substrate.
FIG. 1B is a top view of FIG. 1A with magnetic film 112 formed on substrate 103 between conductive segments 109 and the surface of substrate 103 . Magnetic film 112 coats or partially coats the surface of substrate 103 . In one embodiment, magnetic film 112 is a magnetic oxide. In an alternate embodiment, magnetic film 112 is one or more layers of a magnetic material in a plurality of layers formed on the surface of substrate 103 .
Magnetic film 112 is formed on substrate 103 to increase the inductance of highly conductive path 114 . Methods of preparing magnetic film 112 include evaporation, sputtering, chemical vapor deposition, laser ablation, and electrochemical deposition. In one embodiment, high coercivity gamma iron oxide films are deposited using chemical vapor pyrolysis. When deposited at above 500 degrees centigrade these films are magnetic gamma oxide. In an alternate embodiment, amorphous iron oxide films are prepared by the deposition of iron metal in an oxygen atmosphere (10 −4 torr) by evaporation. In another alternate embodiment, an iron-oxide film is prepared by reactive sputtering of an Fe target in Ar+O 2 atmosphere at a deposition rate of ten times higher than the conventional method. The resulting alpha iron oxide films are then converted to magnetic gamma type by reducing them in a hydrogen atmosphere.
FIG. 1C is a side view of some embodiments of the inductor of FIG. 1A including substrate 103 , the plurality of conductive segments 106 , the plurality of conductive segments 109 and magnetic films 112 and 113 .
FIG. 2 is a cross-sectional side view of some embodiments of highly conductive path 203 including encapsulated magnetic material layers 206 and 209 . Encapsulated magnetic material layers 206 and 209 , in one embodiment, are a nickel iron alloy deposited on a surface of substrate 212 . Formed on magnetic material layer layers 206 and 209 are insulating layers 215 and 218 and second insulating layers 221 and 224 which encapsulate highly conductive path 203 deposited on insulating layers 215 and 218 . Insulating layers 215 , 218 , 221 and 224 , in one embodiment are formed from an insulator, such as polyimide. In an alternate embodiment, insulating layers 215 , 218 , 221 , and 224 are an inorganic oxide, such as silicon dioxide or silicon nitride. The insulator may also partially line the holes, perforations, or other substrate subtending paths. The purpose of insulating layers 215 and 218 , which in one embodiment are dielectrics, is to electrically isolate the surface conducting segments of highly conductive path 203 from magnetic material layers 206 and 209 . The purpose of insulating layers 221 and 224 is to electrically isolate the highly conductive path 203 from any conducting layers deposited above the path 203 and to protect the path 203 from physical damage.
The field created by the conductive path is substantially parallel to the planarized surface and penetrates the coating. In one embodiment, the conductive path is operable for creating a magnetic field within the coating, but not above the coating. In an alternate embodiment, the conductive path is operable for creating a reinforcing magnetic field within the film and within the substrate.
FIG. 3 A and FIG. 3B are perspective views of some embodiments of inductor 301 and sense inductors 304 and 307 of the present invention. In one embodiment, sense inductor 304 is a spiral coil and sense inductor 307 is a test inductor or sense coil embedded in the substrate. Sense inductors 304 and 307 are capable of detecting and measuring reinforcing magnetic field or flux 309 generated by inductor 301 , and of assisting in the calibration of inductor 301 . In one embodiment, sense inductor 304 is fabricated on one of the surfaces substantially perpendicular to the surfaces of the substrate having the conducting segments, so magnetic field or flux 309 generated by inductor 301 is substantially perpendicular to sense inductor 304 . Detachable test leads 310 and 313 in FIG. 3 A and detachable test leads 316 and 319 in FIG. 3B are capable of coupling sense inductors 304 and 307 to sense or measurement circuits. When coupled to sense or measurement circuits, sense inductors 304 and 307 are decoupled from the sense or measurement circuits by severing test leads 310 , 313 , 316 , and 319 . In one embodiment, test leads 310 , 313 , 316 , and 316 are severed using a laser.
In accordance with the present invention, a current flows in inductor 301 and generates magnetic field or flux 309 . Magnetic field or flux 309 passes through sense inductor 304 or sense inductor 307 and induces a current in spiral sense inductor 304 or sense inductor 307 . The induced current can be detected, measured and used to deduce the inductance of inductor 301 .
FIG. 4 is a cutaway perspective view of some embodiments of triangular coil inductor 400 of the present invention. Triangular coil inductor 400 comprises substrate 403 and triangular coil 406 . An advantage of triangular coil inductor 400 is that it saves at least a process step over the previously described coil inductor. Triangular coil inductor 400 only requires the construction of three segments for each coil of inductor 400 , where the previously described inductor required the construction of four segments for each coil of the inductor.
FIG. 5 is a top view of some embodiments of an inductor coupled circuit 500 of the present invention. Inductor coupled circuit 500 comprises substrate 503 , coating 506 , coil 509 , and circuit or memory cells 512 . Coil 509 comprises a conductive path located at least partially above coating 506 and coupled to circuit or memory cells 512 . Coil 509 pierces substrate 503 , is interlaced with substrate 503 , and produces a magnetic field in coating 506 . In an alternate embodiment, coil 509 produces a magnetic field in coating 506 , but not above coating 506 . In one embodiment, substrate 503 is perforated with a plurality of substantially parallel perforations and is partially magnetic. In an alternate embodiment, substrate 503 is a substrate as described above in connection with FIG. 1 . In another alternate embodiment, coating 506 is a magnetic film as described above in connection with FIG. 1 . In another alternate embodiment, coil 509 , is a highly conductive path as described in connection with FIG. 1 .
FIG. 6 is a diagram of a drill 603 and a laser 606 for perforating a substrate 609 . Substrate 609 has holes, perforations, or other substrate 609 subtending paths. In preparing substrate 609 , in one embodiment, a diamond tipped carbide drill is used bore holes or create perforations in substrate 609 . In an alternate embodiment, laser 606 is used to bore a plurality of holes in substrate 609 . In a preferred embodiment, holes, perforations, or other substrate 609 subtending paths are fabricated using a dry etching process.
FIG. 7 is a block diagram of a system level embodiment of the present invention. System 700 comprises processor 705 and memory device 710 , which includes memory circuits and cells, electronic circuits, electronic devices, and power supply circuits coupled to inductors of one or more of the types described above in conjunction with FIGS. 1A-5 . Memory device 710 comprises memory array 715 , address circuitry 720 , and read circuitry 730 , and is coupled to processor 705 by address bus 735 , data bus 740 , and control bus 745 . Processor 705 , through address bus 735 , data bus 740 , and control bus 745 communicates with memory device 710 . In a read operation initiated by processor 705 , address information, data information, and control information are provided to memory device 710 through busses 735 , 740 , and 745 . This information is decoded by addressing circuitry 720 , including a row decoder and a column decoder, and read circuitry 730 . Successful completion of the read operation results in information from memory array 715 being communicated to processor 705 over data bus 740 .
Conclusion
Embodiments of inductors and methods of fabricating inductors suitable for use with integrated circuits have been described. In one embodiment, an inductor having a highly conductive path fabricated from a plurality of conductive segments, and including coatings and films of ferromagnetic materials, such as magnetic metals, alloys, and oxides has been described. In another embodiment, an inductor capable of being fabricated from a plurality of conductors having different resistances has been described. In an alternative embodiment, an integrated test or calibration coil capable of being fabricated on the same substrate as an inductor and capable of facilitating the measurement of the magnetic field or flux generated by the inductor and capable of facilitating the calibration the inductor has been described.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof. | The invention relates to an inductor comprising a plurality of interconnected conductive segments interwoven with a substrate. The inductance of the inductor is increased through the use of coatings and films of ferromagnetic materials such as magnetic metals, alloys, and oxides. The inductor is compatible with integrated circuit manufacturing techniques and eliminates the need in many systems and circuits for large off chip inductors. A sense and measurement coil, which is fabricated on the same substrate as the inductor, provides the capability to measure the magnetic field or flux produced by the inductor. This on chip measurement capability supplies information that permits circuit engineers to design and fabricate on chip inductors to very tight tolerances. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for producing acrylic coated polycarbonate articles; and, more particularly, relates to an improved method for providing protective, ultraviolet radiation cured coating on the surface of a polycarbonate substrate.
2. Description of Related Art
Polycarbonate films generally have acceptable levels of strength and clarity but lack high levels of abrasion resistance and chemical resistance. Radiation curable acrylic coatings and methods for their application to polycarbonate substrates are known, see for example European Patent 228,671 corresponding to European Patent Application 86 117,682. While prior methods exist for applying radiation curable acrylic coatings to polycarbonate film, the adhesion of these cured coatings to the underlying polycarbonate can be less than desirable.
Some prior radiation curable acrylic coating compositions have employed amounts of non-reactive solvents to reduce the viscosity of the coating compositions during application thereof to the polycarbonate substrate. These non-reactive volatile components have been eliminated from the coatings by employing a forced hot air drying system. The use of coating compositions containing substantial levels of non-reactive, volatile components such as solvents, for example more than 1 percent by weight based on the total weight of the composition is not desired because of environmental and safety concerns. Thus there is a need for a method for producing coated polycarbonate articles which involves applying radiation curable coatings substantially free of non-reactive volatile components to polycarbonate substrates to produce coated articles exhibiting good coating adhesion.
Accordingly one object of the present invention is to produce primerless coated polycarbonate articles having high levels of adhesion between the cured coating and the polycarbonate substrate while avoiding the use of non-reactive volatile components such as solvents.
SUMMARY OF THE INVENTION
The present invention involves a method to produce a coated polycarbonate film exhibiting excellent adhesion between the cured coating and the underlying polycarbonate substrate. The method involves the steps of (i) applying an ultraviolet radiation (UV) curable coating composition which is substantially free of non-reactive volatile components, such as solvents, to a surface of thermoplastic resin substrate; (ii) heating the uncured coating composition and the surface of the substrate to a temperature selected from between 90° F. and 150° F. to drive a portion of the uncured coating composition into a region beneath the surface of the thermoplastic resin substrate to create a coating composition penetrated region beneath the surface containing both thermoplastic resin and coating composition; and (iii) ultraviolet radiation curing of the applied coating composition by directing ultraviolet radiation into the coating composition and penetrated region. Upon UV curing of the coating composition, the penetrated region beneath the surface of the thermoplastic resin substrate provides an interlocking bond between the substrate and the cured coating.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a horizontal elevational schematic view of equipment involving a casting drum for practicing the method of the present invention.
FIG. 2 is a cross-sectional view of a coated polycarbonate article made without a heated casting drum.
FIG. 3 is a cross sectional view of a coated polycarbonate article made according to the method of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The method of the present invention provides an ultraviolet radiation-cured coating on the surface of thermoplastic resin substrates. The particular apparatus depicted in FIG. 1 is intended for the application and cure of a coating material on a continuous thermoplastic film substrate. The substrate is preferably made from a polycarbonate resin. The substrate employed in conjunction with the equipment of FIG. 1 should be flexible and capable of allowing the passage of ultraviolet radiant energy therethrough, and the properties of the polycarbonate substrate should not be unacceptably affected by such passage of radiant energy. The radiant energy source is selected to operate at an ultraviolet radiation frequency. A preferred polycarbonate substrate for the method of the present invention is one formed from a thermoplastic polycarbonate material, such as LEXAN® resin, a product of General Electric Company. Typical examples of polycarbonate resins are described in U.S. Pat. No. 4,351,920 which is incorporated herein by reference, and are obtained by the reaction of aromatic dihydroxy compounds with phosgene, as well as those obtained by the reaction of aromatic dihydroxy compounds with carbonate precursors such as diaryl carbonates. U.S. Pat. No. 4,351,920 also describes various methods for the preparation of aromatic polycarbonate resins which may be used as substrates in the present invention. A preferred aromatic dihydroxy compound is 2,2-bis(4-hydroxy phenyl) propane, (Bisphenol-A). The term aromatic polycarbonate resins is meant to include polyester carbonates obtained from the reaction products of a dihydroxy phenol, a carbonate precursor and a dicarboxylic acid such as terephthalic acid and isophthalic acid. Optionally an amount of a glycol may also be used as a reactant. Polycarbonate film may be made by well-known methods. Typically, the molten polycarbonate is cast onto an extrusion roll stack, and both sides of the material are polished and pressed to a uniform thickness. Ultraviolet (UV) radiation is used as the energy source when curing coatings on the polycarbonate substrates. In the conjunction with the equipment of FIG. 1, the thickness of the polycarbonate film substrate may range from about 0.5 mil to about 30 mils, depending upon the ability of the substrate to remain flexible. Preferably the polycarbonate film has a thickness of from 5 to 20 mils.
The ultraviolet radiation-curable coating compositions are generally comprised of monomers and oligomers containing acrylic, methacrylic, and vinylic unsaturation as well as other 100% solids convertible materials (e.g. monomer-soluble polymers and elastomers, inorganic silica fillers and pigments and the like, etc.). The coating systems generally comprise monomers having molecular weights of from about 100 to 1000, and having single unsaturation or di-, tri-, or higher multifunctional unsaturation sites. In the practice of the present invention the coating is substantially free (<1%) of volatile, non-reactive components and preferably the coating compositions are 99 percent to 100 percent by weight reactive components and solid materials and more preferably are 99.9 percent to 100 percent by weight reactive components and solid materials and most preferably are 100 percent by weight reactive components and solid materials. The solid materials include non-volatile solid materials such as polymeric materials and colloidal silica. Suitable polymeric materials include cellulose acetate butyrate. The coating composition is preferably 100% convertible to solids upon exposure to ultraviolet radiation. The coating composition may contain an amount of a latent UV screener such as resorcinol monobenzoate. The composition also contains an amount of a photo initiator effective to permit photocuring of the composition.
The preferred acrylic coating composition contains a substantial level of a relatively low molecular weight aliphatic alkane diol diacrylate which will penetrate, via diffusion, the region below the surface of polycarbonate substrate upon contact and exposure to elevated temperatures. A suitable aliphatic alkane diol diacrylate is 1,6-hexanediol diacrylate. A preferred acrylate coating composition contains from 5 percent to 60 percent by weight of an aliphatic alkane diol diacrylate based on the total weight of the coating composition. The aliphatic diol diacrylate preferably contains from 2 to 12 carbon atoms in the aliphatic portion thereof. Suitable aliphatic diol diacrylates include ethylene glycol diacrylate, butane diol diacrylate, hexane diol diacrylate, octane diol diacrylate, decane diol diacrylate. A preferred coating composition contains about 37 percent by weight trimethylolpropane triacrylate (TMPTA), about 15 percent by weight dipentaerythritol monohydroxy pentacrylate (DIPEPA) 37 percent by weight 2,6-hexanediol diacrylate, about 9 percent cellulose acetate butyrate (CAB) and about 2 percent by weight of the photoinitiator, diethoxyacetophenone (DEAP). A preferred silica filled acrylic coating employs a mixture of 22 percent 1,6-hexanediol diacrylate, 22 percent trimethylolpropane triacrylate, 35 percent functionalized colloidal silica, 7 percent of a latent ultraviolet radiation absorber such as benzene sulfonate ester of Cyasorb® 5411 (BSEX) as described by D. R. Olson, J. Applied Polymer Science 28, 1983, p. 1159 incorporated herein by reference and 3 percent of a photoinitiator such as diethoxyacetophenone (DEAP). Suitable functionalized colloidal silica is set forth in Olson et al, U.S. Pat. No. 4,455,205 ; Olson et al, U.S. Pat. No. 4,491,508; Chung, U.S. Pat. No. 4,478,876 and Chung, U.S. Pat. No. 4,486,504 incorporated herein by reference. The aliphatic alkane diol diacrylate, and more particularly 1,6-hexanediol diacrylate by virtue of its ability to readily swell a thermoplastic matrix such as polycarbonate, facilitates quick and adequate penetration and diffusion of a sufficient amount of the coating composition into the region beneath the surface of the substrate to promote adhesion between the coating and the substrate upon curing of the coating composition. FIG. 3 show an article made according to the present invention which has a cured acrylic coating and a polycarbonate substrate wherein the substrate has a region adjacent its surface which serves to improve adhesion between the coating composition and the substrate.
DETAILED DESCRIPTION OF THE DRAWINGS
A suitable apparatus for applying and curing a coating on the surface of a polymeric substrate in accordance with the method of the present invention is depicted in FIG. 1. In FIG. 1, radiation-curable coating material 10 is continuously applied by flowing it onto the surface of the film at a controlled rate.
Substrate roll 12 is formed from a roll of uncoated substrate 14 surrounding a core 16. Substrate 14 is unwound pursuant to the movement of casting drum 18 (described below). Coating material 10 may be applied to the surface of substrate 14 by dripping of the material onto the substrate 14 by use of an applicator 20. It will be apparent to those skilled in the art that adjustments may be made in the coating system in order to apply the coating to the substrate efficiently. Coating material 10 may be applied to substrate 14 by any of a number of well-known roll coating methods, such as spraying, brushing, curtain coating, and dipping, as well as other well-known roll coating methods, such as reverse roll coating, etc. The thickness of radiation-curable coating 10 applied to the substrate and the thickness of the resultant cured harcoat 21 is dependent upon the end use of the article and the physical properties desired, and their thickness may range from about 0.05 mil to about 5.0 mils for the nonvolatile coating. The preferred thickness is from about 0.2 mil to about 0.5 mil.
After coating material 10 is applied to substrate 14, the coated substrate 22 is guided to nip roll 24. The choice of materials which form the nip roll 24 used in the present invention is not critical. The rolls may be made of plastic, metal (i.e. stainless steel, aluminum), rubber, ceramic materials, and the like. Nip roll 24 may be provided with a sleeve, preferably formed from a resilient material such as tetrafluoroethylene or polypropylene, or from one of the variety of currently available synthetic rubber compounds and blends thereof. The sleeve is snugly fitted over the roll surface to provide a smooth, friction-minimizing surface for contacting substrate 22. Nip roll 24 is adjustable relative to the position of casting drum 18, described below, and may optionally be independently driven.
As shown in FIG. 1, casting drum 18 is situated in a position adjacent nip roll 24, such that the outer circumferences of nip roll 24 and drum 18 are adjacent to each other at an interface defining a nip 26 which is described below. The applied pressure at the interface of nip roll 24 and drum 18 may be adjusted by well known methods, such as air cylinders (not shown), attached to the axle 28 of nip roll 24, which selectively urges the roll toward drum 18. Typically, the applied pressure at the interface is slight, i.e. less than 5 pounds per linear inch, when the substrate is not passing through nip 26. The applied pressure can be readjusted according to a variety of parameters when a substrate having a coating thereon is passing through nip 26, as described below.
Casting drum 18 surrounds central axle 19, and is preferably made from a material which is conductive to heat, and preferably comprised of stainless steel or chromium-plated steel. Furthermore, it is preferred that the drum be independently driven by an outside power source (not shown).
Casting drum surface 30 may be provided with a wide variety of textures or patterns, depending upon the texture or pattern desired to be imparted to coating 10 and the resultant hardcoat 21. For instance, surface 30 may be provide with a highly polished chrome-plated surface if a high degree of gloss is desired for the hardcoat 21. If a lower sheen is desired for the hardcoat 21, surface 30 may be less polished so as to provide a matte texture to the coating. Similarly, a design pattern may be embossed on surface 30 to impart a mirror-image design pattern to hardcoat 21. The cured coating will create a hardcoat 21 which will thus become a permanent mirror-image of casting drum surface 30.
Although a nitrogen blanket may be employed to ensure an anaerobic cure of the coating composition it is preferred that an anaerobic cure be obtained without the use of such a nitrogen blanket. In order to minimize the presence of air in the coating 10 prior to curing, without the use of a nitrogen gas blanket, the pressure capable of being exerted at nip 26 is carefully adjusted. The adjustment of applied pressure at nip 26 may be accomplished as described above. To obtain a certain coating thickness the exact pressure that will be exerted at nip 26 will depend on factors such as the viscosity of coating 10, the substrate speed, the degree of detail in the design pattern on surface 30 (if present), and temperature of the casting drum. Typically, for a substrate having a thickness of 15 mils having applied thereon an acrylic-based coating having a thickness of 0.6 mil and a viscosity of 220 centipoises, at a substrate speed of 50 feet per minute and a roll cover of 55 durometer hardness (Shore A) a nip pressure of 25 pounds/linear inch is applied to the coated substrate. Coating 10 is thereby pressed into contact with both substrate 22 and casting drum surface 30, thereby ensuring that there is a substantial absence of free diatomic oxygen from the coating during curing, so as the ensure a substantially complete curing of the coating and a cured coating, hardcoat 21, exhibiting a mirror image of the texture and/or pattern of casting drum surface 30. Excess coating forms a bead 31 of uncured coating composition material above the nip and across the width of the drum. This bead 31 ensures that adequate coating material enters through the nip 26 across the width of the drum.
After substrate 22 having coating 10 applied thereon passes through nip 26, the coating is cured by means of ultraviolet radiant energy. As shown in FIG. I, means 32 for transmitting ultraviolet radiation energy transmit to ultraviolet radiation energy into a surface 34 of substrate 22 opposite a surface 36 having coating 10 thereon. The radiant energy passes through the transparent substrate 22 and is absorbed by the coating 10, the latter being compressed between substrate 22 and drum surface 30. The preferred wavelength of the UV radiation is from about 2900 Angstroms to about 4050 Angstroms. The lamp system used to generate such UV radiation may consist of discharge lamps, e.g. xenon, metallic halide, metallic arc, or high, medium, or low pressure mercury vapor discharge lamps, etc., each having operating pressures of from as low as a few millitorrs up to about 10 atmospheres. The radiation dose level applied to coating 10 through substrate 22 may range from about 2.0 J/cm 2 to about 10.0 J/cm 2 . A typical UV curing system suitable for the present invention is a Linde medium pressure mercury lamp, as described in U.S. Pat. No. 4,477,529. The number of lamps directing UV light to the surface of the substrate is not critical; however, a greater number of lamps may allow a higher production rate for the substrate having coating 10 thereon. Typically, two lamps, each producing 300 watts/linear inch of radiant energy, are sufficient for an acrylic-based coating having a thickness of about 0.5 mils, when the production line speed is approximately 50 feet/minute. Such a curing procedure should result in both the polymerization of the polyfunctional acrylic monomers and the cross-linking of the polymers to form hard, non-tacky coatings. The coating may receive the post curing by further exposure to ultraviolet radiation after leaving the surfaces of the casting drum.
After the layer of coating material has been applied to and cured on substrate 22 according to the method of the present invention, the resulting product is a hardcoated polycarbonate film article 38 which is guided around idler rolls 40, 42 and 44 then collected on take-up roll 46, the latter typically being independently driven and capable of separating the hardcoated polycarbonate article 38 from drum surface 30.
The improvement of the present invention involves heating the polycarbonate substrate 22 and uncured coating composition 10 to a temperature of from between 90° F. and 150° F. prior to curing of the coating composition 10. While prior coating methods have employed drying systems to remove non-reactive volatiles, including solvents, from the coatings, such drying systems purpose has been to remove non-reactive volatiles and there is no apparent reason why anyone skilled in the art would have heretofore employed such a system for coating compositions which are substantially free of non-reactive volatiles. In the method of the present invention, the applied coating composition 10 needs to be in contact with thermoplastic resin substrate 22 for a sufficient period of time after application of the coating composition 10 and prior to cure thereof and at a sufficient temperature, to cause a sufficient amount of the coating composition to diffuse into a region 47 beneath the surface 34 of the thermoplastic resin substrate 22. Preferably the coating composition 10 penetrates beneath the surface to a depth of from 0.05 microns to 5 microns, more preferably from 0.1 microns to 1 micron and to create a region 47 containing both thermoplastic resin and coating composition. The region 47 is located adjacent the coated surface 34 of the substrate. Preferably the substrate 22 and coating composition 10 are kept in contact at an elevated temperature of from 90° F. to 150° F. for a period of from 1 to 5 seconds. The heating step is not significantly involved in the curing of the coating composition. Upon curing of the coating 10, the penetrated region 47 provides an interlocking matrix of thermoplastic resin and cured coating 21 which locks the coating 10 and the substrate 22 together to improve adhesion therebetween. The step of heating the substrate 22 and coating 10 prior to ultraviolet radiation curing of the coating composition 10 can be accomplished by internally heating drum 18. The drum can be heated internally by hot oil or the like (not shown). The coating composition of the present invention are radiation curable rather than heat curable compositions.
It will be understood by those skilled in the art that a nitrogen blanket may be used alone or in conjunction with the apparatus and preferred methods of the present invention.
The following specific example describes the novel methods and articles of the present invention. It is intended for illustrative purposes of specific embodiments only and should not be construed as a limitation upon the broadest aspects of the invention.
FIG. 2 is a cross-sectional view of a coated article 48 made without a heated casting drum. Note that the coating composition did not penetrate a region beneath the surface 52 of the polycarbonate substrate 51 and thus did not provide a region to lock the cured coating on to the substrate 51.
FIG. 3 is a cross-sectional view of a coated polycarbonate article 38 made according to the method of the present invention. Note that the article 38 of FIG. 3 has a region beneath the surface of the substrate into which an amount of the coating composition has migrated. Upon curing, the region acts to interlock the cured coating and the polycarbonate substrate.
EXAMPLES
The following examples illustrate the improved method of the present invention. Example A is a comparative example and Example B is an example of the improved adhesion obtained by articles made from the process of the present invention.
TABLE 1______________________________________ Cure Speed Roll Temp. Scribed AdhesionExamples.sup.(a) (feet/minute) °F. Tape Test______________________________________A 20 70 FailedB 20 115 Passed______________________________________ | A method for producing an abrasion-resistant, ultraviolet radiation cured coating on a surface of a polymeric substrate is disclosed, as well as the article produced from the method. The uncured coating material which is substantially free of non-reactive volatile components is (i) applied to the substrate (ii) heated along with the substrate to a temperature sufficient to drive a portion of the coating material into a region beneath the surface of the substrate, (iii) and cured onto the substrate by exposing the coating material under anaerobic conditions to sufficient ultraviolet radiation to cure the coating material. Heating of the solvent-free coating prior to ultraviolet radiation cure and while in contact with the substrate results in improved adhesion of the coating to the substrate. |
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT
The government may have rights in this invention pursuant to Subcontract 22287 issued from the Office of Naval Research/Henry M. Jackson Foundation.
BACKGROUND OF THE INVENTION
The present invention relates generally to analyzing digital imaging, and more particularly to computer aided detection (CAD) of abnormalities in a three dimensional (3D) mammography method, system, and apparatus.
It is well know in the medical community that breast cancer is a leading cause of death in women (and to a lesser extent also affects men). When early detection of abnormalities is combined with proper medical attention, however, the risk of death and/or severe medical ramifications can be drastically reduced. Many devices and techniques (e.g., mammography) are currently under development to detect breast abnormalities earlier, and with greater accuracy than conventional devices. A brief summary of some conventional devices, techniques, and their limitations follows.
Presently, the vast majority of mammography devices utilize conventional x-ray techniques. A patient's breast is positioned in an x-ray machine, which passes x-rays through the breast and generates a corresponding x-ray image on a film. The film is then analyzed by a trained clinician, who examines the film for abnormalities, such as a mass, a cyst, a microcalcification, a fibrous finding, an architectural distortion, and/or other abnormal findings related with benign or malignant abnormalities. In standard digital mammography, the x-ray image (or projection radiograph) is acquired by means of a digital detector, and the resulting digital image can be processed to enhance the visibility of structures within the image, thus providing a potentially more useful image to the clinician. These standard mammography techniques, however, suffer from many problems.
One problem with film based mammography can be generally referred to as film saturation. To fully penetrate through dense parts of the breast, a higher dose of radiation is utilized, generally on the order of about 3 Gy. In relatively dense parts of the breast, a sizeable amount of the radiation is absorbed by the dense tissue, the residual radiation exposing the film. Due to the large x-ray absorption within the dense tissue, the film is not saturated by too much residual radiation, and thus provides sufficient contrast for detecting abnormalities. Near the edges of the breast (e.g. near the skin surface), however, the higher dose of radiation is absorbed to a lesser extent, thus a higher amount of residual radiation exposes the film, which results in film saturation. Film saturation can lead to lower contrast (if any at all) especially near the edges of the breast, and may hinder the clinician's ability to properly identify an abnormality.
Furthermore, the 2D nature of standard mammography techniques (including standard digital and film based) also leads to superposition (e.g., overlay) problems. Superposition can occur when multiple structures are overlaid onto the same position in the projection image. The overlaid normal (i.e., non-malignant) structures may end up combining in appearance to appear as an abnormality, resulting in a “false positive” identification of an abnormality. Presently, the false positive rate is relatively high: on the order of between 70% and 90% of biopsies are normal. Conversely, real abnormalities may be superimposed over dense tissue regions which “hide” the abnormality within the dense tissue, resulting in a “false negative” miss of an abnormality. Thus, in standard 2D imaging (e.g., projection radiography) structures within the breast may become superimposed with each other, thereby normal structures within the breast can “interfere” with a clear interpretation of structures of interest (e.g., potentially malignant) which are located at a different height (relative to the projection direction) within the imaged object.
Another problem with many mammography techniques is related to contrast and structural orientation issues. Radiation passing through the breast is used to generate a view of the breast. “Image slices” of the breast are then generated from multiple views using conventional or newly developed algorithms. As used herein “image slice” is a single image representative of the structures within an imaged object (e.g., breast tissue) at a fixed height above the detector. Abnormalities having a substantial size in the direction approximately parallel to the detector surface will thus generally appear in the image with sufficient contrast and size to be detected by a trained clinician. Abnormalities having a relatively small size in the direction approximately parallel to the detector surface (e.g., a thin duct running substantially perpendicular to the detector surface), however, may only appear as a very small dot in the image. The “dot” like appearance of abnormalities that do not run substantially parallel to the detector surface may hinder the clinician's ability to properly identify an abnormality.
Another problem with conventional mammography techniques is directly related to the importance of having trained and experienced clinicians examining the image (e.g., the film). Without proper training (or even through inadvertence of a trained clinician), abnormalities may be missed, especially when they are relatively small or low contrast in appearance. Moreover, even a well trained clinician generally will not always be able to fully analyze the image in view of previous mammograms and/or patient history (e.g., family history, prior mammograms, health history, lifestyle history, etc.) due to time considerations, fatigue, etc., such that the clinician may not always catch a progression of tissue growth or tissue changes that would be more apparent when considering the additional information.
On inspection of mammograms by a clinician, sometimes radiologists identify suspicious regions (e.g., abnormalities) and request follow up examinations of the breast with ultrasound, nuclear medicine and/or further diagnostic x-rays. The follow up ultrasound and/or nuclear medicine examinations, however, are generally conducted on an entirely different machine than the mammography device, these machines commonly having an entirely different patient configuration and/or image acquisition geometry for different modalities. It is thus difficult (if even possible) to spatially correlate image acquisitions from other modalities with the mammograms. Thus, there is some uncertainty as to whether the follow up scan locates and characterizes the same region. Indeed, it has been estimated that at least 10% of the masses that were identified on ultrasound scans as corresponding to the mammographically suspicious regions were found to correspond to very different regions in the breast. In fact, this percentage is expected to be significantly higher in patients with dense breasts.
Thus, a need exists for an improved method and apparatus for the detection of abnormalities within tissue.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed at improving and/or eliminating one or more of the problems set forth above, and other problems found within the prior art.
According to one aspect of the present invention, a method of analyzing a plurality of views of an object is provided, the object including an edge portion partially extending from a surface of the object into an internal volume of the object, comprising the step of analyzing each acquired view. The step of analyzing each acquired view includes analysis of the edge portion.
According to another aspect of the present invention, a program product for causing a machine to analyze a plurality of views from a tomosynthesis system is provided, the tomosynthesis system imaging an object including an edge portion partially extending from a surface of the object into an internal volume of the object, the program product causing the machine to perform the step of analyzing each acquired view. The step of analyzing each acquired view includes analysis of the edge portion.
According to another aspect of the present invention, a tissue imaging device is provided comprising a radiation source for emitting radiation through tissue to be imaged, the radiation source being angularly displaceable through a plurality of emission positions corresponding to a plurality of views, a detector positioned to detect radiation emitted through the tissue, the detector generating a signal representing an view of the tissue, and a processor electrically coupled to the detector for analyzing the signal. The processor analyzes each acquired view, the analysis including analysis of an edge portion of the tissue partially extending from a surface of the tissue into an internal volume of the tissue.
According to another aspect of the present invention, a method of analyzing an object with a multi-modality imaging system is provided comprising the steps of detecting a region of concern in at least one of a first image of the object generated by a first modality and a second image of the object generating by a second modality, classifying the detected region of concern, correlating the region of concern with a corresponding region in the other of the first image and the second image, and weighting the classification with a weighting factor corresponding to a degree of correlation. The first modality is different from the second modality. Preferably, the first image and the second image are fused together. More preferably, the first image is registered with the second image, and differences in spacial resolution between the first image and the second image is corrected.
According to another aspect of the present invention, an imaging system for imaging an object is provided comprising means for generating a first image of the object from x-ray radiation, means for generating a second image of the object from ultrasound, means for detecting a region of concern in at least one of the first image and the second image, means for correlating the detected region of concern with a corresponding region in the other of the first image and the second image, means for at least one of determining whether the abnormality is present in the corresponding region in the other of the first image and the second image and comparing at least one of a shape of the detected region of concern, a size of the detected region of concern, a contrast of the detected region of concern, and a contrast distribution of the detected region of concern, means for classifying the abnormality and means for weighting the classification in relation to a degree of correlation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a tomosynthesis device according to an embodiment of the present invention.
FIG. 2 is a flow chart of a method of analyzing an image according an embodiment of the present invention.
FIG. 3 is a flow chart of a method of analyzing an image including reconstruction according an embodiment of the present invention.
FIG. 4 is a flow chart of a method of analyzing an image including reconstructing a 3D image according an embodiment of the present invention.
FIG. 5 is a flow chart of a method of analyzing an image including reconstruction according an embodiment of the present invention.
FIG. 6 is a flow chart of a method including various correlating steps according an embodiment of the present invention.
FIG. 7 is a flow chart of a method of analyzing a reconstructed 3D image according an embodiment of the present invention.
FIG. 8 is a block diagram of a multi-modality imaging device according to an embodiment of the present invention.
FIG. 9 is a flow chart of a method of analyzing an image according an embodiment of the present invention.
FIGS. 10–13 depict an image from tomosynthesis and/or ultrasound acquisition according an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to presently preferred embodiments of the present invention. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
The present invention will be described in reference to apparatuses and methodology for breast imaging and breast cancer detection. It should be appreciated, however, that the teachings of the present invention may also be used in other areas, such as lung imaging, brain imaging, liver imaging, kidney imaging, bone imaging, and other medical areas, as well as in industrial applications, such as detecting low density regions in fabricated parts, or performing fault/fatigue testing (e.g., examining for cracks, depressions, or impurities).
In recent years, research into improved imaging systems for breast cancer detection has focused on digital imaging systems, and more particularly, to digital imaging systems with automated abnormality detection and risk analysis. A two part article entitled “Mammographic Tissue, Breast Cancer Risk, Serial Image Analysis, and Digital Mammography” by John J. Hein, PhD, which is incorporated by reference herein in its entirety, provides a review of breast tissue-risk research, and its application to digital mammography.
3D digital tomosynthesis is one such new x-ray imaging system that creates 3D digital images of tissue (e.g., breast tissue). A suitable tomosynthesis device is described in copending application entitled “Tomosynthesis X-Ray Mammogram System And Method With Automatic Drive System” which is incorporated by reference herein in its entirety. Another suitable tomosynthesis device is described in U.S. Pat. No. 5,872,828 which is also incorporated by reference herein in its entirety.
A tomosynthesis device according to one embodiment of the present invention is shown in FIG. 1 . A radiation source 110 for emitting x-ray radiation is angularly displaceable through a plurality of emission positions A, B, C corresponding to a plurality of views of the tissue 120 . While only three emission positions are shown in FIG. 1 , one of ordinary skill in the art will recognize that three emission positions or fewer or more emission positions may be utilized, while remaining within the scope of the invention. The radiation source 110 is angularly displaceable so as to enable acquisition of radiographs of the breast from different projection angles. This can be achieved, for example, by angularly displacing the radiation source 110 about a pivot point 150 , preferably about 15cm above the breast tissue. The radiation source 110 is angularly displaceable through a projection angle A, which is preferably less than ±180°. Preferably, A is in the range of less than about ±45°, and most preferably less than about ±30°. More preferably, at least 11 emission positions are used, and spaced at about constant angular spacings. In the system configuration of FIG. 1 , the projection angle A is generally significantly smaller than the “gantry angle” A. The projection angle A is essentially given by the angle of a ray of the beam passing through the “center” of the object, with reference to some “zero-degree” angle. Unlike in computed tomography (CT) scanning, the radiation source 110 is preferably not angularly displaceable all the way around the breast tissue 120 .
A detector 130 is positioned substantially opposite of the radiation source 110 , with respect to the imaged object 120 to detect radiation emitted through the tissue 120 , the detector generating a signal representing a view of the tissue 120 . Preferably, the detector 130 is positioned less than about 25 cm (most preferably about 22.4 cm) below the pivot point 150 . The signal is transmitted to a computer 160 , including a processor for analyzing the view (and reconstructing image slices 140 ). Preferably, the computer is part of a tomosynthesis device including the radiation source 110 and the detector 130 . Alternatively, the signal may be stored on a storage media or transmitted to a central computer system, and later analyzed by computer 160 . Such a configuration may occur, for example, with a mobile tomosynthesis system that takes data of a patient's breast at a remote site, which is later analyzed at a laboratory.
Other tomosynthesis system configurations are also plausible, as would be readily apparent to one of ordinary skill in the art after reading this disclosure. One such system may employ a radiation source movable along a track rather than on a rotating gantry, preferably with a radiation source to detector distance in the range of about 100 cm to about 180 cm. The aforementioned configurations have been provided for purposes of illustration only, and are not limiting on the scope of this application.
The 3D data set (i.e., image(s)) taken by the tomosynthesis system are processed by a computer aided detection (CAD) device (i.e., computer 160 ), to take advantage of the significant increase in information available in 3D data sets over conventional 2D data sets. In this way, the advantages of 3D data are combined with the conventional 2D images to achieve a new, higher level of performance in mammography imaging as will be described in greater detail below.
Improved performance is at least partially related to the fact that the image data is acquired at various orientations A, B, C with respect to the breast 120 and any pathology it may contain. This allows better separation of true structure from superimposed tissue, correlation of information in different acquisition positions, correlation of spatial structures in the 3D image sets, and 3D specific processing for enhanced performance.
The inventors have discovered, however, that the signal:to:noise ratio (SNR) per view for tomosynthesis tends to be lower than in conventional film/screen mammography due to the larger number of acquisitions without substantially increasing the patient's exposure to radiation for health concerns. The ability to reconstruct 3D images, reduce structure noise, and reduce the implication of superpositioning far outweighs the disadvantages (e.g., lower SNR performance) which would teach away from using a tomosynthesis technique. Furthermore, the advantages of having a large dynamic range and a priori knowledge of the detector and system characteristic also provides greater advantages than the foreseeable disadvantages which would teach away from using this approach. Specific examples of methodology to achieve this improved performance is set forth below.
FIG. 2 depicts a block diagram of a method of analyzing a plurality of views of breast tissue according to an embodiment of the present invention. The method can be performed, for example, by a computer workstation for processing data from a tomosynthesis device, or by a processor within a tomosynthesis device itself.
In step 210 , a tomosynthesis device acquires a plurality of views through breast tissue or any other object to be imaged. Step 210 can be performed in a manner as described in the aforementioned copending applications. The plurality of views are then sent to a processor for analysis.
In step 220 , the processor detects at least one region of concern in a first view (if such a region exists). If the processor detects at least one region of concern, the processor then classifies the detected region of concern (e.g., as a mass, a cyst, a microcalcification, etc.) in step 230 using a new or conventional algorithm. Exemplary algorithms can be found, for example, in “Application of Computer-Aided Diagnosis to Full-Field Digital Mammography” by L M Yarusso et. al, which is incorporated by reference herein in its entirety. The processor then correlates the detected region of concern with a corresponding region in a second view in step 240 . Preferably, the processor correlates the detected region of concern with a corresponding region in a plurality of other views in step 240 .
The processor then weights the classification of step 230 with a weighting factor corresponding to a degree of correlation in step 250 . As referred to herein, the term “degree of correlation” relates to the similarity of one image to another image. Thus, if the degree of correlation is high, this represents greater confidence that the classified region is classified correctly. As shown in FIG. 6 , for example, correlating may comprise at least one of steps 610 , 620 , 630 , 630 , 640 and 650 . In step 610 , the processor determines whether a corresponding region exists in any other view, reconstructed plane (as will be described below), or reconstructed 3D image (as will be described below). Thus, if no corresponding region exists, there is a low probability that the region of concern is, in fact, an abnormality at all and the classification is weighted accordingly. Furthermore the shape of the detected region of concern (step 620 ), the size of the detected region of concern (step 630 ), the contrast of the detected region of concern (step 640 ), the contrast distribution of the detected region of concern (step 650 ), and the correlation with the same in a corresponding region can be individually or in combination used to weight the classification with a weighting factor corresponding to a degree of correlation.
The results of the analysis are then outputted in step 260 . Step 260 may comprise, for example, selectably displaying the information as described in copending application entitled “Method and Apparatus For Providing Mammographic Image Metrics To A Clinician” which is incorporated by reference herein in its entirety. Other output methods are also plausible, as would be readily apparent to one of ordinary skill in the art after reading this disclosure.
As shown in FIG. 3 , the processor preferably also reconstructs a plurality of reconstruction planes from the plurality of views in step 232 . Reconstruction planes may include, for example, (i) image slices parallel to the detector 130 (i.e., substantially perpendicular to the z-axis); (ii) planes substantially perpendicular to the x and y axis; and (iii) oblique planes at any orientation in the 3D volume. Reconstruction techniques as used in “Limited-Data Computed Tomography Algorithms for the Physical Sciences” by D. Verhoeven which is incorporated by reference herein in its entirety, may, for example, be used for this approach.
Preferably, the processor then correlates the detected region of concern from step 220 with a corresponding region in a reconstruction plane in step 242 . Step 242 can be performed in a similar fashion as described above for step 240 . Alternatively, step 242 can be performed in place of step 240 .
As shown in FIG. 4 , the processor preferably also reconstructs a 3D image of the breast from the plurality of views in step 234 . Step 234 can be performed, for example, as described in copending application entitled “Generalized Filtered Back-Projection Reconstruction In Digital Tomosynthesis”, which is incorporated by reference herein in its entirety. Preferably, the processor then correlates the detected region of concern from step 220 with a corresponding region in the 3D image in step 244 . Step 244 can be performed in a similar fashion as described above for step 240 . Alternatively, step 244 can be performed in place of step 240 .
As would be readily apparent to one of ordinary skill in the art after reading this disclosure, detection step 220 and classification step 230 can also be performed directly on a reconstructed plane and/or on the reconstructed 3D image, rather than directly on a view or in combination therewith. Thus, as shown in FIG. 5 , for example, the processor need not perform steps 220 , 230 , 240 , and 250 (i.e., view analysis) if the processor performs steps 222 , 231 , 246 , and 252 (i.e., reconstructed plane analysis). Similarly, the processor may only perform reconstructed 3D image analysis if desired. In a preferred embodiment, however, the processor performs view analysis, reconstructed plane analysis, reconstructed 3D image analysis, and combinations thereof to achieve a higher degree of performance.
Additional analysis can be taken on the reconstructed 3D image as shown, for example, in FIG. 7 . In step 710 , image data along a line may be summed to simulate a ray projection along that line. In step 720 , a maximum intensity projection within a detected region of concern can be determined. In step 730 , a minimum intensity projection within a detected region of concern can be determined. In step 740 , a mean intensity projection within a detected region of concern can be determined. In step 750 , a median intensity projection amongst detected regions of concern can be determined. Steps 710 , 720 , 730 , 740 , and 750 can be performed individually, in combination, and/or with other steps using new or conventional techniques, and thereby provide additional analysis tools to achieve an even higher degree of performance.
In the above described embodiment, the 2D projection data acquired at the individual angles in the tomosynthesis acquisition scan can be used to more accurately detect pathologies. The correlations between the views, the reconstructed planes, and/or the reconstructed 3D image enhances detection by confirming that the location of a particular “finding” (i.e., a classified abnormality) in a projection at one angle is well defined in some or all others as well. In addition, the size of the finding, its contrast, its contrast distribution, etc. can all be used in combination or individually as described to determine the correlation of these parameters in different projections. The probability of a finding being important is increased as the correlation of the parameters in the different projections increases. Thus, the number of “false positive” identifications can be effectively decreased, while simultaneously reducing the number of “false negative” identifications.
Furthermore, the reconstructed planes tend to have a more limited range of data, which eases detection of pathologies since voxel values (i.e., 3D boxes at each reference point within a reconstructed 3D image) are more directly related to feature characteristics, and less to the geometry of the imaging. Moreover, volumetric information can be considered in the classification of pathologies in the reconstructed 3D image, such as taking neighborhood information into account. This allows characterization of the full volume of the finding directly. Full volume characterization can be particularly beneficial in detecting long, thin, string-like features, where the continuity of the structure in the “string direction” could be lost in a 2D analysis. String detection loss in 2D analysis is especially prevalent if the analysis planes are perpendicular to the string direction, and noise, for example, interrupts the tracing of the 3D length of the feature.
The detection described above can be done on the data directly, or after image processing to enhance specific features. In addition, image processing to reduce or remove certain artifacts specific to the tomosynthesis acquisition geometry can be used. Spatial resolution of the image can also be modified in the processing. Specifically, the data can be down sampled or interpolated to change the effective voxel size, to improve performance or reduce computational load. Searches for findings can be done in a multi-resolution fashion, with initial searches for larger findings done on a coarser grid, and finer searches for smaller findings done on higher resolution image sets. This down sampling or interpolation may be particularly appropriate in the z-direction, where the spatial resolution of the tomosynthesis images is inherently the largest. Methods which make use of multiple views or 3D reconstructed images generally benefit from improved SNR compared to single projection methods.
The probability that a finding is of interest can be assigned by using a weighted combination of results as described. In this way, all the information can be combined in the most effective way to increase the sensitivity and specificity of the results. SNR and spatial localization information can also be used in determining the proper weighting. These probabilities can also be correlated with patient age, health history, tissue type in the breast, tissue type in the neighborhood of finding, knowledge about pathology type and morphology (e.g., minimum number of microcalcifications in a cluster before it is deemed important) and other key parameters to improve performance, as CAD allows for automatic computation and consideration of many parameters in addition to the data sets generated by the tomosynthesis device.
Furthermore, the entire process can be automated in a CAD device to reduce the dependency on trained and experienced clinicians. This too will improve accuracy and reduce the number of false positive and false negative classifications.
Additional improvements are also plausible as would be readily apparent to one of ordinary skill in the art after reading this disclosure. According to a preferred embodiment, the tomosynthesis device further includes an imaging device operating at a different modality (e.g., ultrasound, nuclear medicine, etc.) as will be described in detail below. It should be appreciated that the above described features may also apply to the multi-modality imaging device described below.
A multi-modality imaging device according to an embodiment of the present invention is shown in the block diagram of FIG. 8 . A similar device is the subject of copending application entitled “Combined Digital Mammography And Breast Ultrasound System” which is incorporated by reference herein in its entirety. As shown in FIG. 8 , one or more of an ultrasound emitting device 1100 and/or a plurality of nuclear medicine detectors 1120 are provided as additions to the tomosynthesis device of FIG. 1 . Preferably, ultrasound emitting device 1100 is applied after x-ray imaging takes place, so as to not adversely affect the x-ray imaging of the tissue 120 . The positioning and number of ultrasound emitting devices 1100 and nuclear medicine detectors 1110 (e.g., gamma radiation detectors) can be adjusted as would be readily apparent to one of ordinary skill in the art after reading this disclosure. The specific methodology of a multi-modality system will be described below.
A method of analyzing an object with a multi-modality imaging system according to an embodiment of the present invention is shown in the flow chart of FIG. 9 . A first image of the object (preferably a 3D image) is generated using an x-ray modality in step 910 . A second image of the object (preferably a 3D image) is generated in step 920 using a different modality (e.g, ultrasound or nuclear medicine). Steps 910 and 920 may be performed as described in copending applications. The remaining description of this embodiment will be described specifically in reference to an x-ray/ultrasound multi-modality system. However, the disclosure similarly applies to other modalities including nuclear medicine (e.g., single photon emission computed tomography (SPECT) or positron emission tomography (PET)), etc. Preferably, the object being imaged in steps 910 and 920 is restrained in substantially the same position during image acquisition (e.g., by a compression device such as a compression paddle).
In step 930 , a region of concern is detected in at least one of the first image and the second image. Step 930 can be similarly performed as described for step 220 . As shown in FIGS. 10–13 , for example, mass 10 and cyst 20 can be seen in both the x-ray image (Tomo) and the ultrasound image (US). Thus, step 930 may detect, for example, either the mass 10 , the cyst 20 , or both in either the Tomo image, the US image, or both. It should also be appreciated that detecting a region of concern in the Tomo image may detect a region of concern in a view, a reconstructed plane, and/or a reconstructed 3D image as previously described. Similarly, detecting a region of concern in the ultrasound image may detect a region of concern in a view, an image plane, and/or a 3D image.
The detected region of concern is then classified in step 940 (e.g., classified as a cyst, a mass, a microcalcification, etc.). The detected region of concern is then correlated with a corresponding region in the other of the first image and second image in step 950 . Correlating may include, for example, steps similar to steps 610 , 620 , 630 , 640 , and 650 in FIG. 6 but for modality to modality in addition to multiple views (e.g., views, reconstructed planes, reconstructed 3D image, etc.) within a given modality. The classification is then weighted in step 960 based on a degree of correlation. The results of the analysis are then outputted in step 970 .
The inventors have found considerable advantages from utilizing the above described multi-modality approach in addition to the advantages described above for other embodiments of the present invention. In general, the use of supplementing modalities (i.e., in addition to x-ray) provides for much greater data to analyze the object to be imaged. For example, conventional x-ray devices tend to have high resolution in planes parallel to the detector surface as can be seen in FIG. 10 . However, x-ray devices tend to have a much lower resolution in planes perpendicular to the detector surface, as shown in FIG. 11 . Generally, the resolution for ultrasound depends on the orientation of the transducer relative to the x-ray detector, the resolution being generally lower in the direction in which the transducer is swept. Thus, preferably, the ultrasound acquisition is arranged to have low resolution in planes parallel to the detector surface ( FIG. 10 ), and high resolution in planes perpendicular to the detector surface ( FIG. 11 ) to achieve high resolution in planes where the x-ray resolution is relatively low. This arrangement can be achieved by positioning the transducer perpendicular to the x-ray detector and above the breast. By this configuration, an overall improvement in resolution can be achieved simply by combining these two approaches.
Moreover, the overall confidence in classifications (i.e., a reduction in false negative and false positive identifications) can be dramatically improved by correlating detection of abnormalities across multiple modalities as described, as different modalities tend to detect different characteristics of objects better than others. Improved classification can also be achieved by detecting abnormalities directly in a fused image (see FIG. 13 ) with greater overall resolution in all directions. Thus, by correlating detecting regions of concern within a given modality or between different modalities, or by analyzing a region of concern within a fused image, the overall performance of image analysis can be improved.
It should be noted that although the flow chart provided herein shows a specific order of method steps, it is understood that the order of these steps may differ from what is depicted. Also two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen, which is generally considered a matter of designer choice. It is understood that all such variations are within the scope of the invention. Likewise, software and web implementation of the present invention could be accomplished with standard programming techniques with rule based logic and other logic to accomplish the various database searching steps, correlation steps, comparison steps and decision steps.
The foregoing description of preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents. | There is provided a method of analyzing a plurality of views of an object, the object including an edge portion partially extending from a surface of the object into an internal volume of the object, comprising the step of analyzing each acquired view. The step of analyzing each acquired view includes analysis of the edge portion. Preferably, the object comprises breast tissue. |
BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION
This invention relates in general to a method and apparatus for disassembling wooden pallets to recover the individual components thereof.
Wooden pallets are commonly used in commerce to handle and carry a wide range of goods and cargo. In particular, pallets are used in the transportation of boxes, crates or bag loads from one place to another. These wooden pallets are typically constructed of a plurality of generally parallel spaced apart ribs positioned between a plurality of parallel slats which are spaced apart from each other and fastened to the top and bottom edges of the ribs at a generally right angle therewith.
Wooden pallets are frequently damaged in use due to the heavy loads carried and to the rough handling to which they are subjected by the lift trucks used in transporting them. The damage typically consists of one or more of the slats or ribs being broken or cracked, making further use of the pallet unsafe. In the past, broken pallets were most often discarded. However, the escalating cost of lumber and the superior strength of aged wood now make it profitable and desirable to salvage the sound boards for use in the construction of new pallets.
Presently, wooden pallets are most often disassembled by hand. In performing this operation, a workman uses a crowbar to forceably pry the slats away from the rib pieces. This technique, however, is time consuming, costly and extremely inefficient since many of the sound boards are broken or cracked as a direct result of this operation.
Another problem often associated with the use of wooden pallets entails the handling of the pallets after they are used in the delivery of goods to a destination customer. Quite often, the destination customer has no further use for the pallets in his business and, as a result, simply discards the pallets as trash. This course of action, however, results in the waste of wood which could be put to good use of the pallets were disassembled.
It is therefore an object of the present invention to provide a method and apparatus for quickly and easily disassembling wooden pallets to recover the individual components of such pallets.
Another object of the present invention is to provide a method and apparatus for disassembling wooden pallets in a simple and efficient manner with minimal damage to the sound boards of the pallet.
A further object of the present invention is to provide a method and apparatus for disassembling wooden pallets wherein a pallet may be quickly and easily disassembled by a single operator to reduce the cost of the operation.
It is an additional object of the present invention to provide a method and apparatus for quickly and easily disassembling wooden pallets of varying widths.
It is yet another object of the present invention to provide a method and apparatus for disassembling wooden pallets such that the nails used to fasten the slats to the internal ribs of the pallet do not protrude outward from the separated slats thereby making handling of the separated slats safer.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.
DETAILED DESCRIPTION OF THE INVENTION
In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are employed to indicate like parts in the various views:
FIG. 1 is a perspective view of pallet disassembling apparatus which is constructed according to the preferred embodiment of the present invention, parts being broken away for purposes of illustration;
FIG. 2 is a side elevational view on an enlarged scale of an individual cutting assembly used in the pallet disassembling of FIG. 1 with portions broken away for the purposes of illustration;
FIG. 3 is an end view of the cutting assembly shown in FIG. 2;
FIG. 4 is a fragmentary sectional view on an enlarged scale taken generally along line 4--4 of FIG. 3 in the direction of the arrows; and
FIG. 5 is a cross sectional view on an enlarged scale taken generally along line 5--5 of FIG. 3 in the direction of the arrows.
Referring now to FIG. 1, numeral 10 generally designates a pallet disassembling apparatus which is constructed in accordance with the preferred embodiment of the present invention. The disassembling apparatus of the present invention includes a loading station 11 where the pallets to be disassembled are received and a disassembling station 12 where the components of the received pallets are separated.
The loading station is comprised of a frame having four legs 13, 14, 15 and 16 which rest on the floor or another support surface. The frame also has a horizontal receiving table 17 secured to it. This table presents a flat surface for receiving and holding the next pallet to be disassembled. Table 17 has a rectangular shaped notch 18 cut out of the front edge thereof.
A pallet 19 is shown in FIG. 1 in position on table 17. Pallet 19 is representative of the type of pallets which this apparatus is capable of handling. In particular, the pallet is comprised of a plurality of spaced apart ribs 20 which are arranged in a parallel configuration. A plurality of wood slats 21 are fastened to the lateral edges of each rib by means of nails or some other type of fastening means having a shank portion extending from the slat into the rib. The slats are spaced apart from each other and are fastened to the lateral edges of each rib at a generally right angle therewith.
A loading platform 22 is hingedly coupled to the frame of the loading station adjacent to table 17. A pneumatic or hydraulic cylinder 23 is appropriately coupled with the underside of the loading platform to move this platform about its hinge coupling. A side retaining wall 24 is fixed to the frame of the loading station adjacent to table 17 so that the wall extends upward therefrom at a right angle therewith.
The disassembling station 12 is comprised of a support frame having four vertical legs 25, 26, 27 and 28 which rest on the ground or other support surface. These vertical legs are coupled with each other at the top of the support frame by means of a plurality of crosspieces 29, 30, 31 and 32. A pair of lower crosspieces 33 and 34 cooperate to form a working table for supporting a pallet in the desired on-edge position at the disassembling station. Crosspiece 33 is a generally U-shaped piece which is fixedly secured to legs 26 and 27 while crosspiece 34 is a generally U-shaped piece which is fixedly secured to legs 25 and 28. These two crosspieces are spaced apart from each other to provide an open channel between them.
A second pallet 35 is shown on the working table formed by crosspieces 33 and 34. This pallet is identical in design to pallet 29 and, in particular, is constructed of a plurality of interior ribs 36 and exterior slats 37. The interior ribs 36 are spaced apart from each other in a parallel relationship. The exterior slats are in turn fastened to the lateral edges of each rib by means of nails 38 or some other type of fastening means as earlier described.
The pallet disassembling machine is equipped with a plurality of cutting assemblies 39 which are operable to detach the exterior slats from the internal ribs of a pallet properly positioned on the working table formed by crosspieces 33 and 34. Each of the cutting assemblies is of identical design and construction. The design and construction of these cutting units will be described in greater detail below.
The cutting assemblies are carried by a crosshead 40 having a pair of spaced apart parallel plates 40a and 40b. The cutting assemblies are mounted to the crosshead in spaced apart relationship with the spacing between each cutting unit being substantially equal to the distance between the pallet's internal ribs. While the number of cutting assemblies is variable, it is preferable to have a direct correspondence between the number of ribs and cutting assemblies. The crosshead may also be equipped with extra holes to accommodate more cutting assemblies or to vary the spacing between the cutting assemblies.
The crosshead 40 is in turn supported from the structural frames of the disassembling station by means of a pair of hydraulic actuators 41 and 42 which operate in unison to move the crosshead and cutting assemblies carried by it in a vertical path. Hydraulic actuator 41 is a double acting cylinder having a pair of ports 43 and 44 and a piston rod 45 which is secured to the crosshead by means of a mounting bracket 46. This cylinder is mounted to the frame of the disassembling station by means of a mounting collar 47 which is attached to the frame by means of a crosspiece 48. Hydraulic actuator 42, on the other hand, is also comprised of a double acting cylinder which is equipped with a pair of ports 49 and 50 and a piston rod 51. This piston rod is in turn secured to the crosshead by means of a bracket 52. Hydraulic actuator 42 is likewise mounted to the structural frame of the disassembling station by means of mounting collar 53 which is in turn attached to the frame by means for a crosspiece 54.
A motor 55 and pump 56 are provided to produce a source of hydraulic pressure for the operation of the actuators. The motor and pump are mounted to the structural frame for the disassembling station by means of a platform 57 which is fixedly secured to the frame. A manually operated conventional remote valve control system (not shown) is used to control the operation of the actuators.
A locking member 58 is provided to hold a pallet in place on the working table of the structural frame of the disassembling station. The locking member is hingedly coupled with a crosspiece 59 which is fixedly secured between legs 25 and 26 of the frame. The locking member is hand operated and is movable to engage one of the internal ribs of the pallet to stabilize the pallet in the upright position.
Pallets are delivered to the disassembling station from the loading station by means of a conveying belt 60. The conveying belt is driven by a motor 61 which is mounted to the structural frame of the disassembling station by means of a mounting bracket 62. The drive shaft 63 of this motor carries a pulley 64. Conveying belt 60 passes around pulley 64 and around another pulley 65 which is mounted to the front portion of the loading station's structural frame by means of a horizontal shaft 66. The conveying belt carries a plurality of spaced apart lugs such as 67. These lugs protrude outward from the belt and serve as grabbing arms which engage the front rib of a pallet at the loading station to convey this pallet to the disassembling station. A pair of side plates 68 and 69 are positioned on each side of the conveying belt to provide a track on which the pallet may ride. One end of each side plate is coupled with the loading station's structural frame while the other end of each side plate is coupled with the structural frame of the disassembling station. In this way, the side plates provide a track on which pallets may be conveyed to the disassembling station from the loading station by means of the conveying belt 60. At the disassembling station, the conveying belt rides within the open channel between crosspieces 33 and 34 to bring the pallet into position on the working table.
A pair of conveyor belts 70 and 71 are positioned on each side of the disassembling station to facilitate handling of the separated boards. Conveyor belt 70 is carried by an idler pulley 72 which is mounted to the structural frame of the disassembling station by means of a horizontal shaft 73 while conveyor belt 71 is carried by a similar pulley which is not shown in this figure. Both of these conveyor belts may be driven by a common motor which is not shown in this figure. A pair of deflecting plates such as 74 are attached to the structural frame of the disassembling station below the working table formed by crosspieces 33 and 34 to direct the separated pieces of the pallet onto conveyor belts 70 and 71 for removal of these pieces from the working area of the machine.
Reference is now made to FIGS. 2, 3, 4 and 5 for a more detailed description of the cutting assemblies. As shown principally in FIGS. 2 and 3, each cutting assembly includes a pair of circular metal saws 75 and 76 which are carried by a common drive shaft 77 and an electric motor 78 for imparting rotatable movement to this drive shaft. The cutting assembly is shown in these figures in operating relationship with one of the ribs of a pallet. The rib is shown in broken lines and is designated by the numeral 79. Two of the slats fastened to this rib are also shown in this figure in broken lines and are designated by the numerals 80 and 81.
The drive shaft 77 is supported by and between a pair of vertically oriented support members one of which is identified as the mounting plate member 82 and the other as the cover plate member 83. Mounting plate 82 is arranged to have an upper mounting portion 82a, which is secured to the one crosshead plate 40a by means of a pair of nut and bolt assemblies 84, and an integral lower protective covering portion 82b which is sized and positioned to provide an outer protective cover adjacent saw blade 76. An L-shaped mounting bracket 85 has horizontal base leg 85a rigidly secured to the inner surface of the mounting plate. The vertical leg 85b of this bracket is secured to the other crosshead plate 40b by means of a pair of nut and bolt assemblies which are designated by the numeral 86. The bolts of fastening assemblies 84 and 86 extend through bolt holes formed plates 40a, 40b and through a bolt hole and an arcuate adjusting opening in the respective cutter carrier mounting members 82a and 85b.
Cover plate 83 is generally of inverted L-shape and is constructed to have a vertical side wall 83a and an upper horizontal leg 83b which is integrally formed with the side wall. Leg 83b lies adjacent the underside of the horizontal leg 85a of member 85 and is slidably supported on a shelf-like plate 87 which is anchored at one end to and extends in cantilever fashion from the inside surface of mounting plate 82.
Referring now principally to FIGS. 3 and 4, cover plate 83 is coupled with mounting plate 82 by means of a pair of nut and bolt assemblies 88 and 89. Cover plate 83 is coupled with the mounting plate 82 such that the blade covering portion 83a of cover plate 83 is spaced apart from the blade covering portion 82b of the mounting plate 82. In particular, the mounting portion of covering plate 83 is slipped within the space formed by the base leg 85a of L-shaped bracket 85 and the shelf-like plate 87. Shelf-like plate 87 and the base leg 85a of L-shaped bracket 85 are each provided with a pair of circular holes (not shown in these figures) which receive nut and bolt assemblies 88 and 89. The mounting portion 83b of cover plate 83, is however, provided with a pair of elongate slots 90 and 91 for receiving nut and bolt assemblies 88 and 89, respectively. In this way, cover plate 83 is coupled with mounting plate 82 such that the side wall 83a of covering plate 83 is capable of relative movement with respect to the covering portion 82b of the mounting plate 82 to vary the spacing between them. In particular, covering plate 83 is capable of moving toward and away from mounting plate 82 with the amount of away movement being controlled by the length dimension of slots 90 and 91. A pair of compression springs 92 and 93 are provided to bias covering plate 83 at an extended position. Compression springs 92 and 93 are respectively received in recesses 94 and 95. These springs also abut against the inner surface of the mounting plate 82 to exert a force on cover plate 83 which tends to resiliently bias this plate away from the mounting plate.
The bottom edges of both the blade covering portions of the mounting and cover plates are beveled as at 82c and 83c, respectively. In addition, the bottom edges are reinforced, in each case by a reinforcing plate 96 or 97, respectively, which is secured to the inside surface of its associated blade cover plate. The reinforcing plates have beveled surfaces which extend below and form a continuation of the bevels 82c, 83c and terminate in a knife-like edge located directly below its associated saw blade. The upper edge of each reinforcing plate is curved to conform with the rim of the saw blade, being spaced slightly away from it to permit free rotation of the blade. The thickness of the reinforcing plate at the curved edge is such that it coincides with or extends slightly inwardly past inner face of the blade.
The mounting plate and its associated reinforcing plate have a positioning notch 98 located in the bottom edge thereof to fit down over the shank of a nail or other fastening device used to secure a slat to the lateral edge of the rib corresponding to this plate. A similar positioning groove (not shown) is located in the bottom edge of the cover plate 83 and its associated reinforcing plate 97. A pair of guide fingers 99 and 100 are attached to the bottom portion of covering plate 83 and mounting plate 82, respectively. These fingers extend downward from the bottom portion of these plates and have a generally inward curvature.
Referring now particularly to FIGS. 2, 3 and 5, and as earlier noted each cutting assembly is also provided with a pair of circular metal cutting saw blades 75 and 76. Blade 75 is positioned adjacent to the side wall 83a of mounting plate 83 while blade 76 is positioned adjacent to the lower covering portion 82a of mounting plate 82. Each of the blades has a diameter large enough to overlap a portion of the positioning notch (such as 98) which is defined in its associated cover and reinforcing plates.
Both of the circular blades are mounted to a common shaft 77. Shaft 77 is comprised of an outer sleeve 101 and an inner core 102 which interact in a telescoping manner. In other words, the inner core 102 is capable of sliding inward or outward relative to and within tube 101. A pin 103 is secured to and extends radially outward from the outer surface of the inner core. This pin is received by a longitudinal slot 104 in the wall of tube 101 for longitudinal movement therein. This type of arrangement forces both parts of the shaft to rotate in unison while still allowing the inner core to move relative to the outer cylinder in a telescoping manner. A compression spring 105 is positioned within the tube to bias the inner core toward an extended position. One end of this compression spring rests against the circular edge of the inner core while the other end rests against the inner wall of the hollow cylinder.
The inner core 102 of the shaft assembly is carried by and journaled in a bearing 106 having a flange which is attached to the outer surface of cover plate 83 by means of a pair of threaded pins 107 and 108. These pins are fixedly secured to the outer surface of the cover plate and protrude outward there from at a right angle therewith. These pins are arranged to receive locking nuts 109 and 110 which secure the bearing to the covering plate.
The outer tube 101 of the shaft is carried by and journaled in another bearing 112 secured to the outer surface of mounting plate 82 by means of a pair of threaded pins 113 and 114 which are attached to the outer surface of this plate. These threaded pins are arranged to threadably engage locking nuts 115 and 116 to secure the bearing flanges to the mounting plate.
Blade 75 is mounted to the inner core 102 of shaft 77 by means of a mounting collar 117 which is fixably secured to the core portion of the shaft. Mounting collar 117 includes a threaded portion 117a which is arranged to receive a locking nut 118 and an enlarged retaining plate 117b which is arranged to contact the flat side surface of the blade. Blade 75 is provided with a center hole 119 which allows for the mounting collar to be inserted through it to position the blade on shaft 77. This saw is then secured to the mounting collar by means of locking nut 118 which threadably engages the threaded portion of the mounting collar.
Blade 76, on the other hand, is mounted to the outer tube 101 of shaft 77 by means of a mounting collar 120 which is fixably secured to the outer cylinder of the shaft. This mounting collar is also provided with a threaded portion 120a which is arranged to receive a locking nut 121 and an enlarged retaining plate 120b which is arranged to contact the flat side surface of the blade. The mounting collar is arranged to pass through hole 122 in the blade to position the plate on the shaft. The blade is then secured in place on the mounting collar by means of the locking nut 121 which threadably engages the threaded portion of the mounting collar.
With reference now to FIGS. 2, 3 and 5, each cutting assembly is provided with an electric motor 78 which is arranged to impart rotational motion to shaft 77. Motor 78 is mounted to the outer surface of mounting plate 82 by means of a mounting bracket 123. This motor drives a pulley 124 which is mounted on the drive shaft 125 of this motor. A drive belt 126 is passed around pulley 124 and around a pulley 127 which is carried by shaft 77 to impart rotatable movement to this shaft.
In operation, pallet is initially placed on loading platform 22 so that the pallet is resting on one set of its slats with the internal ribs of the pallet in a generally perpendicular orientation with respect to the receiving table 17. Thereafter, hydraulic cylinder 23 is activated to move the loading platform upward about its hinged coupling. In particular, loading platform 22 is moved to a vertical position causing the loaded pallet to be placed on the receiving table 17. Pallet 19 is shown in FIG. 1 in position on the receiving table as shown in the figure, pallet 19 is resting on the table such that the internal ribs of the pallet are in a vertical position and such that the front rib intersects notch 18. Since the receiving table is only slightly wider than a pallet the side retaining wall 24 and the loading platform cooperate to properly orient the pallet on the receiving table.
After the pallet is in place on the receiving table, electric motor 61 is energized by appropriate manual switch means (not shown) to transfer this pallet to the disassembling station. Activation of motor 61 causes conveyor belt 60 to be driven in a direction such that the upper run of the belt is moving from the receiving station to the disassembling station. As the belt continues to move, one of the protruding lugs 67 passes through notch 18 and comes in contact with the inner wall of the first rib. This lug grabs the rib and pulls to the disassembling station over the track fromed by plates 68 and 69.
At the disassembling station, the conveyor belt continues to move the pallet along the working table which is formed by crosspieces 33 and 34, until the pallet appears to be properly positioned with respect to the cutting units. Once the pallet appears to be properly positioned on the working table, motor 61 is turned off and the pallet is manually adjusted to align each rib of the pallet with its corresponding cutting assembly. In particular, the pallet is moved on the working table until the nails or other pins used to fasten the slats to the internal ribs are aligned with the positioning groove in their corresponding mounting or cover plate. In this position, each cutting assembly stradles its corresponding rib such that the cover plate corresponds with one lateral edge of the rib while the mounting plate corresponds with the rib's other lateral edge.
The electric motor associated with each cutting assembly is then activated, causing rotatable movement to be imparted to its associated shaft 77 by means of its attendant pulley 124, drive belt 126 and pulley 127. This rotatable movement in turn causes the unit's circular cutting blades 75 and 76 to rotate in unison. Thereafter, hydraulic actuators 41 and 42 are made operable to drive downward crosshead 40 and the cutting units carried by it.
As a cutting unit moves downward, its positioning fingers 99 and 100 come into contact with the inner surface of the first set of slats fastened to the cutting unit's corresponding rib. These positioning fingers cooperate to adjust the spacing between cover plate 83 and mounting plate 82. If the spacing between these plates is greater than the width of the pallet, the positioning fingers force the covering plate toward the mounting plate to properly position the sharp edge of the reinforcing plate 96 secured to the mounting plate 82 at the junction between the rib's lateral edge associated with this plate and the first slat fastens to this edge of the rib and the sharp edge of reinforcing plate 97 at the junction between the rib's lateral edge associated with the plate and the first slat fastened to the edge of the rib.
Continual downward movement of the cutting unit causes the sharp edge of the reinforcing plate 96 and the sharp edge of reinforcing plate 97 to enter the joint between the rib and the first slat. The beveled nature of the mounting plate 82 and its attendant reinforcing plate 96 causes the first slat to be forced away from the edge to which it is fastened to thereby create between them a gap wherein a portion of the nails or other fastening elements used to secure this slat to this lateral edge of the rib are exposed. The covering plate 83 and its attendant reinforcing plate 97 have a similar effect upon the slats fastened to the lateral edge of the rib corresponding to these plates. As the cutting unit continues to move downward, the exposed portion of each successive nail enters the positioning notch in its corresponding plate. Further downward movement of the cutting unit causes the positioning notch to guide the cutting assembly so that each of these fastening pins is brought into contact with the cutting edge of its associated circular saw. Upon contacting the cutting edge, the nails are severed and the slat separated from this rib. The cutting assembly continues to move downward in this manner until all of the slats are removed from the rib.
It should be noted at this time that the cutting assembly is operable to simultaneously separate slats from each side of the internal rib corresponding to this unit. In addition, all of the cutting units operate in unison to simultaneously separate the slats from all of the ribs of the pallet.
While a pallet is being disassembled at the disassembling station, another pallet may be loaded into the apparatus at the loading station by placing this pallet on the loading platform as described above. The hydraulic cylinder 23 associated with this platform is then activated to position this pallet on the receiving table. The loaded pallet is then maintained in position on the receiving table until the pallet at the disassembling station has been completely disassembled.
The detached slats fall onto conveyor belt 70 or conveyor belt 71 depending upon which side of the pallet these slats are located. Conveyor belts 70 and 71 serve to convey the separated components of the pallet away from the disassembling station and to provide these components to a central receiving location. Once the last slat has been completely detached from the internal ribs of the pallet, the hydraulic actuators are reversed causing the cross head and cutting unit carried by it to be returned to their original position. Thereafter, the motor used to drive the circular saws of each cutting unit is shut off and motor 61 is activated causing the loaded pallet at the receiving station for separation of the slats from the internal ribs of the pallet.
I have also found that it is possible with some pallets to employ cutting assemblies in which the blades 75 and 76, and associated drive means, are either not activated or eliminated entirely. In this embodiment of the invention, the cutting assemblies are so located relative to the pallet that the nails are engaged during downward movement of the cutting assemblies by the knife-like cutting edges 82d, and 83d. Continued downward movement of the cutting assemblies results in shearing of the nails and consequent separation of the slats from the ribs.
From the foregoing, it can be seen that the pallet disassembling machine of the present invention is one well adapted to quickly and easily separate the slats of the pallet from its internal ribs with minimal damage to the individual components.
It will be understood certain features and some combinations are of utility and may be employed without reference to other features and subcombinations.
As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense. | A method and apparatus for disassembling wooden pallets is disclosed. The pallet disassembling apparatus includes a working table for supporting a pallet in an upright position for disassembly. The slats are detached from the ribs of the pallet to which they are nailed or similarly fastened by means of a plurality of cutting assemblies which are positioned such that one cutting assembly corresponds with each rib of the pallet. The cutting assemblies are carried by a cross head which is driven in a vertical path to bring each cutting assembly into engagement with each slat fastened to its corresponding rib. Each cutting assembly includes a pair of opposing plates having sharp edges for partly separating a slat from its corresponding edge of the rib to thereby create between them a gap wherein a portion of the nail or fastening member used to secure this slat to its corresponding edge of the rib is exposed. The sharp edges may also be employed to shear the nails or each cutting assembly also may include a motor driven circular saw blade positioned adjacent to each plate of the cutting assembly. The opposing plates, and if included, saw blades, of the cutting assemblies are coupled with each other so that they are capable of moving relative to each other to accomodate pallets of varying widths. |
This application claims benefit of Ser. No. 60/050,970 filed Jun. 19, 1997.
FIELD OF THE INVENTION
The present invention is directed generally to biosensors that are useful in the identification and analysis of biologically significant nucleic acids. The biosensors of the present invention and their applied methods provide a means for the direct analysis of nucleic acid hybridization and, therefore, have application to a myriad of biological fields including clinical diagnostics.
BACKGROUND OF THE INVENTION
The detection and identification of microorganisms is a problem common to many areas of human and veterinary health. For example, the detection of pathogenic species such as Salmonella typhimurium, Listeria monocytogenes , and Escherichia coli , which are causative agents of major food borne epidemics, is a great concern within the food industry with respect to the quality and safety of the food supply. In other areas of human and veterinary health care, detection and identification of infectious diseases caused by pathogenic microorganisms and viruses is a first step in diagnosis and treatment. For example, it is estimated that 10-15 million office visits per year are for the detection and treatment of three major pathogens—Chlamydia ssp., Trichomonas vaginalis and Gradenerella vaginitis . Infections of these organisms annually effect 3.75 million, 0.75 million and 1.5 million patients, respectively.
Classical techniques routinely used for the detection and identification of microorganisms are often labor intensive, involving plating procedures which require lengthy analysis times. To illustrate, the method currently employed for the detection of Listeria monocytogenes in food and feed commodities involves a three stage analysis. The analysis begins with enrichment of the sample to be analyzed in a nutrient broth for 2 to 4 days. After the enrichment period, plating of the sample onto selective agar media is done and the sample is allowed to incubate for 2 days in order to obtain colonies for biotyping and serotyping, which may take as long as 20 days to complete (McLauchlin et al., 1988, Microbiology Review, 55: 578).
Detection processes based on culturing require analysis times which are too lengthy for effective monitoring and timely intervention to prevent the spread of biohazardous materials or treat disease. In addition, although these methods have been improved over the last decade, the chance of obtaining false negative results is still considerable, and many microorganisms are difficult to culture. Thus, plating/culture methods are limited with respect to their sensitivity, specificity, and lengthy analysis times that are required.
In order to shorten the time required to detect and identify pathogenic bacteria, viruses and genetic diseases, rapid tests such as enzyme immunoassays (EIA) have been developed (Olapedo et al., 1992). Although immunoassay techniques can be very sensitive and effective, there are practical drawbacks which have restricted the use of these methods. Such drawbacks include the need for highly skilled personnel, lengthy analysis and preparation times, and the large quantities of costly reagents that are required to do such analysis.
With the advent of nucleic acid amplification techniques (the polymerase chain reaction), the in-vitro amplification of specific sequences from a portion of DNA or RNA is now possible. Detection of very low numbers of microorganisms has been demonstrated (Rossen et al., 1991; Golsteyn et al., 1991; Wernars, K., et al., 1991). The polymerase chain reaction technique is sensitive and specific but involves complex manipulations in carrying out the tests and is not particularly well-suited for large numbers of samples. Due to the sensitivity of Polymerase Chain Reaction (PCR) technology, special rooms or areas for sample preparation and analysis are required to prevent contamination. In many tests PCR results must be confirmed by additional hybridization analysis. RNAs are difficult to assay by PCR but are very important for human viral detection. In general, PCR needs to be automated for acceptance as a practical diagnostic tool. Hybridization methods require as much as three or four days to complete results. Although the actual hybridization step can be as short as 18 hours, the entire detection process of a DNA/DNA hybrid can take as long as three days with a radioisotope marker.
Thus, there is a great need for simpler, faster and more cost-effective means for detecting specific biologically important RNA and DNA sequences in the fields of human and veterinary in-vitro diagnostics, food microbiology, and forensic applications.
Biosensors developed to date begin to overcome drawbacks associated with the current state of the art in detecting and identifying microorganisms. A biosensor is a device which consists of a biologically active material connected to a transducer that converts a selective biochemical reaction into a measurable analytical signal (Thompson et al., 1984. Trends in Analytical Chemistry, 3: 173; Guilbault, 1991, Current Opinion in Biotechnology, 2: 3). The advantages offered by biosensors over other forms of analysis include the ease of use (by non-expert personnel), low cost, ease of fabrication, small size, ruggedness, facile interfacing with computers, low detection limits, high sensitivity, high selectivity, rapid response, and reusability of the devices.
Biosensors have been used to selectively detect cells, viruses, other biologically significant materials, biochemical reactions and immunological reactions by using detection strategies that involve immobilization of enzymes, antibodies or other selective proteins onto solid substrates such as quartz and fused silica (for piezoelectric and optical sensors) or metal (for electrochemical sensors) (Andrade et al., 1990, Biosensor Technology: Fundamentals and Applications, R. P. Buck, W. E. Hatfield, M. Umana, E. F. Bowden, Eds., Marcel Dekker Inc., NY, pp. 219; Wise, 1990, Bioinstrumentation: Research, Developments and Applications, Butterworth Publishers, Stoneham, Mass.). However, such sensors are not widely available from commercial sources due to problems associated with the long-term stability of the selective recognition elements when immobilized onto solid surfaces (Kallury et al 1992, Analytical Chemistry, 64: 1062; Krull et al, 1991, Journal of Electron Microscopy Techniques, 18: 212).
An alternative approach is to create biosensors with long-term chemical stability. One such approach takes advantage of the stability of DNA. With the recent advent of DNA probe technology, a number of selective oligomers which interact with the DNA of important biological species, for instance salmonella, have been identified (Symons, 1989, Nucleic Acid Probes, CRC Press, Boca Raton, Fla.; Bock et al., 1992, Nature, 355: 564; Tay et al., 1992, Oral Microbiology and Immunology, : 344; Sherman et al., 1993, Bioorganic & Medicinal Chemistry Letters, 3: 469). These have been used to provide a new type of biorecognition element which is highly selective, stable, and can be easily synthesized in the laboratory (Letsinger et al., 1976, Journal of the American Chemical Society, 98: 3655; Beaucage et al., 1981, Tetrahedron Letters, 22: 1859; Alvarado-Urbina et al., 1981, Science, 214: 270).
Until recently, the only other research group in existence which has published work done on the fluorimetric detection of nucleic acid hybridization immobilized onto optical substrates is that of Squirrell et al. (C. R. Graham, D. Leslie, and D. J. Squirrell, Biosensors and Bioelectronics 7 (1992) 487-493.) In this work, single-stranded nucleic acid sequences ranging in length from 16-mer oligonucleotides to 204-base oligomers functionalized with an aminohexyl linker at the 5′ terminus were covalently attached to optical fiber sections functionalized with 3-aminopropyl triethoxysilane via a gluteraldehyde linkage. All investigations of nucleic acid hybridization were done by monitoring fluorescence intensity in an intrinsic mode configuration using complementary strands which had been previously labeled with a fluorescein moiety. This yielded a reusable assay system in which signal generation was observed to occur within minutes and nanomolar detection was achieved. However, this optical sensor technology developed by Squirrell et al. does not contain a transduction element which can transduce the binding event in a reagentless manner. For this assay to function, the target strands must be labeled prior to doing the assay in order for detection, making this technique unsuitable for practical applications.
Abel and co-workers (Abel, A. P.; Weller, M. G.; Duveneck, G. L.; Ehrat, M. and Widmer, H. M. Anal. Chem. 1996 68, 2905-2912) of Norvartis Ltd. (formerly Ciba-Geigy Ltd.) have recently reported an automated optical biosensor system. Their device utilizes 5′-biotinylated-16-mer oligonucleotide probes bound to an optical fiber functionalized with avidin to detect complementary oligonucleotides pre-labeled with fluorescein moieties in a total internal reflection fluorescence (TIRF) evanescent wave motif similar to that of Squirrell. Each assay consisted of a 3 minute pre-equilibration, 15 minute hybridization time, 10 minute washing procedure followed by a 5 minute regeneration cycle (chemical or thermal). A chemical denaturation scheme was observed to be the preferred embodiment for sensor regeneration as exposure of the oligonucleotide functionalized optical sensor to temperatures exceeding 52° C. caused irreversible damage to the device, owing to denaturation of the avidin used for immobilization. This limitation renders the device function labile against sterilization techniques, such as autoclaving, and also indicates that rigorous cleaning of the sensor surface, such as by sonication, would also compromise the integrity of the sensor via denaturation of the affinity pair used to anchor the probe oligonucleotide. In order to detect nucleic acids not pre-labeled with fluorescein, and to overcome the limitation of Squirrell, a competitive binding assay was employed by Abel and co-workers. Detection of the unlabelled analyte was done by pre-treatment of the sensor with fluorescein labeled “tracer-DNA” followed by monitoring decreases in the fluorescence intensity of the sensor upon exposure to and subsequent displacement of the tracer-DNA by complement analyte nucleic acid. The dose-response curves reported by Abel et al. show a detection limit of 132 pmol (8×10 13 molecules) for this detection strategy. However, in addition to high detection limits and the inability of the device to withstand sterilization, this device cannot be classified as a biosensor technology due to the necessity for external treatment with tracer-DNA in order to achieve transduction.
The prior art with respect to patent literature contains many examples of “sensor” devices which are based on nucleic acid molecules immobilized on waveguide supports and transduction strategies based on evanescent excitation. The technology of Gerdt and Herr (David. W. Gerdt, John. C. Herr “Fiber Optic Evanescent Wave Sensor for Immunoassay”, U.S. Pat. No. 5,494,798) describes detection of nucleic acid hybridization based on alterations in the quantity of light transmitted from one optical fiber in a coupled fiber system (similar to that of a Mach-Zehnder interferometer) to the second fiber of the waveguide system. The quantity of light transferred is a function of the refractive index of the media on or surrounding the waveguides. Refractive index alterations affect the penetration depth of the evanescent wave emitted from the first waveguide into which optical radiation is launched. This standing wave of electromagnetic radiation subsequently propagates into (and thus transfers optical radiation to) the second waveguide. Therefore, the device is sensitive to refractive index alterations occurring within a volume surrounding the first waveguide with a thickness of ca. one wavelength of the light propagating within that waveguide. One of the arms of the waveguide may be functionalized with immobilized nucleic acid molecules which serves to provide selective binding moieties. The change in refractive index of the thin film of nucleic acids on the first waveguide upon the occurrence of hybridization with target nucleic acid sequences alters the quantity of light transferred to the second waveguide, thereby providing a means of signal transduction. Hybridization events may then be identified based on changes in the output ratios of the two waveguide arms in the coupled fiber system. One limitation of this technology lies in the fact that any alterations in refractive index near the surface of the waveguides will provide alterations in the output ratios of the two fibers. Therefore, non-specific binding events (such as protein adsorption) will provide false positive results.
In order to avoid the problem of interferents providing false positive results, a transduction strategy which is sensitive to the structure of the binding pair (i.e. recognition element and target) is required. The technologies of Fodor, Squirrell (David James Squirrell “Gene Probe Biosensor Method” International Application Number PCT/GB92/01698, International Publication Number WO 93/06241, International Publication Date: Apr, 1, 1993.), Sutherland et al. (Ranald Macdonald Sutherland, Peter Bromley and Bernanrd Gentile “Analytical Method for Detecting and Measuring Specifically Sequenced Nucleic Acid.” European Patent Application Number 87810274.8, Publication Number 0 245 206 A1, Date of Filing: Apr, 30, 1987.), Hirschfeld (Tomas B. Hirschfeld, “Nucleic Acid Assay Method” U.S. Pat. No. 5,242,797, Date of Patent: Sept. 7, 1993.), and Abel et al. (Andreas P. Abel, Michael G. Weller, Gert L. Deveneck, Markus Ehrat, and H. Michael Widmer, Analytical Chemistry , 1996, 68, 2905-2912.) overcome this limitation by using fluorescent probes which associate with the binding pair or are attached to selective binding moieties capable of binding to a portion of the binding pair. These inventions provide methods to measure nucleic acid hybridization on waveguide surfaces based on evanescent excitation and TIRF. In each embodiment, an oligonucleotide probe capable of selective binding to a target sequence is covalently immobilized on a waveguide surface. For the cases of Squirrell and Abel et al., each define two preferred embodiments for the detection of hybridization events. The first embodiment of Squirrell and Abel et al. are essentially identical wherein the target nucleic acid is functionalized with a fluorescently detectable agent (by chemical or enzymatic methods) as a first step prior to detection. Upon hybridization between the labeled target and immobilized nucleic acid, the fluorescent agent is then bound in close proximity to the waveguide surface where it may be excited by evanescent wave formation and emission from the fluorophore collected and quantitatively measured. In the second preferred embodiment of Squirrell, hybridization between the immobilized oligonucleotide and the target sequence is first done. Subsequent to the first hybridization event, a fluorescently labeled oligonucleotide present in the system may then undergo hybridization with all or a portion of the remainder of the target sequence not hybridized with the immobilized sequence. The binding of the third (labeled) oligonucleotide provides a fluorescent species bound in close proximity to the waveguide which may furnish transduction via evanescent excitation and collection of the emitted radiation. In the second embodiment of Abel et al, a method for the detection of nucleic acids not pre-labeled with a fluorescent moiety via a competitive binding assay is described. Detection of the unlabelled analyte was done by first pre-treating the optical sensor with immobilized probe nucleic acid with fluorescein labeled “tracer-DNA”. The quantity of tracer-DNA may be monitored via the evanescent excitation and collection motif. Binding of the analyte could be followed by monitoring decreases in the fluorescence intensity from the sensor as a function of the displacement of the tracer-DNA via competitive binding with non-fluorescent analyte nucleic acid in a dose-response convention.
In the methods of Sutherland et al. and Hirschfeld, transduction of hybridization events is provided by fluorescent intercalating dyes (e.g. ethidium bromide). Following hybridization between the single-stranded target and immobilized probe nucleic acids, intercalant fluorescent dye molecules from solution insert into the base stacking regions of the immobilized double-stranded nucleic acid. An increase in the fluorescence quantum efficiency, fluorescence lifetime, stokes shift of the fluorescent intercalant probes often occurs upon association with double-stranded nucleic acid. It is claimed by the inventors that these enhanced features may be monitored by evanescent excitation and collection of fluorescence emission.
Fodor et al. have employed light-directed chemical synthesis to generate miniaturized, high density arrays of oligonucleotide probes. DNA oligonucleotide arrays have been fabricated using high-resolution photolithography in combination with solid-phase oligonucleotide synthesis. This form of DNA chip technology may be used for parallel DNA hybridization analysis, directly yielding sequence information from genomic DNA segments. Prior to sequence identification, the nucleic acid targets must be fluorescently labeled, either prior to or after hybridization to the oligonucleotide array, via direct chemical modification of the target strand or by use of an intercalant dye subsequent to hybridization on the DNA chip. The hybridization pattern, as determined by fluorescence microscopy, is then deconvolved by appropriate chemometric processing to reveal the sequence of the target nucleic acid. Rather than focusing on selective detection of trace quantities of a particular nucleic acid sequence, this technology has focused on sequence analysis of nucleic acids in suitably high copy number so as to sufficiently occupy the oligonucleotide array.
Notwithstanding the indubitable accomplishments of the aforementioned prior art, there yet exists limitations in these technologies for which further improvements are most desirous. Although the strategies employed by Sutherland et al. and Hirschfeld overcome the limitations of Gerdt and Herr with regard to signal origin and the generation of false positive results, these assay methods are limited by the amount of signal which can be generated by evanescent excitation. For multimode waveguides, less than 0.01% of the optical radiation carried within the waveguide is exposed to the outer medium in the form of an evanescent wave (R. B. Thompson and F. S. Ligler, “Chemistry and Technology of Evanescent Wave Biosensors” in Biosensors with Fiberoptics , Eds.: Wise and Wingard, Humana Press Inc., New Jersey,1991, pp.111-138.). In the case where monomodal waveguides are used, ca.10% of the radiation carried by the waveguide is exposed to the outer medium in the form of an evanescent wave (David. W. Gerdt, John. C. Herr “Fiber Optic Evanescent Wave Sensor for Immunoassay”, U.S. Pat. No. 5,494,798). In the classic total internal reflection fluorescence (TIRF) evanescent wave configuration, the critical angle (θ c ) for the waveguide/solution interface (θ c W/S ) is larger than θ c for the waveguide/biological film interface (θ c W/B ), only the evanescent component of the propagated radiation will enter the biological film. The principle of optical reciprocity states that light coupled back into a waveguide as a plane wave will be in the same way as the primary process when a plane wave generates an evanescent wave (Ranald Macdonald Sutherland, Peter Bromley and Bernanrd Gentile “Analytical Method for Detecting and Measuring Specifically Sequenced Nucleic Acid” European Patent Application Number 87810274.8, Publication Number 0 245 206 A1, Date of Filing: Apr 30, 1987, p.13.). Thus, for the fluorophores excited by evanescent waves created from modes propagating at or near θ c W/S , none of the fluorescence emission can be coupled back into the waveguide in the same propagation mode as θ c W/S would be >90° (U. J. Krull, R. S. Brown and E. T. Vandenberg, “Fiber Optic Chemoreception” in Fiber Optic Chemical Sensors and Biosensors , vol.2, Ed. O. S. Wolfbeis, CRC Press, Boca Raton, 1991, pp.315-340.). Hence a large portion of the signal would be lost to the surroundings for systems in which fluorescence emission originates from thin films of a lower refractive index than that of the waveguide onto which they are immobilized. It has been shown by Love et al. that under optimal conditions, only 2% of the light emitted by the fluorophore in the medium of lower refractive index may be captured and guided by the fiber (W. F. Love, L. J. Button and R. E. Slovacek, “Optical Characteristics of Fiberoptic Evanescent Wave Sensors: Theory and Experiment” in Biosensors with Fiberoptics Eds.: Wise and Vingard, Humana Press Inc., New Jersey, 1991, pp. 139-180.).
SUMMARY OF THE INVENTION
The present invention concerns biosensors for direct detection of nucleic acids and nucleic acid analogs. The device comprises a light source, a detector, and an optical element for receiving light from the source and conveying it to an interaction surface of the optical element. A nucleic acid or nucleic acid analog for a particular nucleic acid sequence or structure (i.e. which is complementary to the target nucleic acid(s)), is immobilized onto the interaction surface of the optical element. Fluorescent ligands are provided that will bind into or onto the hybridized nucleic acid complex and fluoresce when stimulated by the light source. Subsequent to excitation by electromagnetic radiation of suitable wavelength bound within the optical element, the resultant fluorescence is collected within the optical element and guided to the detector to signal that the target nucleic acid(s) has complexed with the immobilized probe and thus indicate the presence of the target in the sample. An interaction surface is defined to mean a surface of the optical element on which nucleic acid is immobilized, and at which the fluorescent molecules interact with the light.
This invention provides biosensors in which the interaction surface is functionalized with nucleic acid probe sequences such that the index of refraction of the immobilized layer (Substrate Linker/Nucleic Acid/Fluorescent Ligand) is equal to or greater than the refractive index at the surface of the waveguide such that the organic coating becomes an extension of the waveguide. The index of refraction of the immobilized layer is dependent, at least in part, on the loading of immobilized molecules and linkers on the surface and the chemical nature of the immobilized molecules and any linkers.
Preferred biosensors which offer high-sensitivity and low-detection limits may be realized by activating the interaction surface of an optical element with substrate linker molecules of at least about 25 Å (Angstrom) in length followed by attachment of a selected probe nucleic acid sequence to that linker. (A probe nucleic acid is, at least in part, complementary to a target nucleic acid.) The preferred method for attachment of the probe nucleic acid to the substrate linker is by in-situ synthesis of the nucleic acid sequence onto the linker terminus using solid-phase nucleic acid synthesis methods or routine modifications of thereof. Such methods of in-situ synthesis are particularly useful for immobilization of nucleic acids of 50 or fewer bases and more particularly useful for nucleic acids of 30 or fewer bases.
The fluorophore may be tethered to the immobilized DNA, for example, by use of a hydrocarbon tether. The use of tethered probes can significantly reduce biosensor response time as the response mechanism is not diffusionally controlled. The associated fluorophore provides for internal calibration of optical source intensity and detector drift. It also provides for calibration of photobleaching, and provides for internal calibration by monitoring bound against free dye by use of, for example, time-resolved fluorescence measurements.
The optical element preferably comprises an optical waveguide which also conveys the fluorescent light to the detector. The optical waveguide preferably conveys the emitted light by total internal reflection to the detector. The optical waveguide can comprise an optical fiber, a channel waveguide, or a substrate that confines light by total internal reflection. The fluorescent molecules preferably provide sufficient Stokes shift such that the wavelength of the light source and the wavelength of the fluorescent light are easily separated. The fluorescent molecules can be provided in a solution in which the optical element is immersed, or by a tether to the nucleic acid that is immobilized to the linker.
In the practice of the present invention, the light source can be any suitable source such as a gas laser, solid state laser, semiconductor laser, a light emitting diode, or white light source. The detector can be any suitable detector such as a photomultiplier tube, an avalanche photodiode, an image intensifier, multi-channel plate, or semiconductor detector. The biosensor system can be a multi-wavelength, multi-fluorescent system. The light coupling of the system can also be modified to allow a multitude of disposable biosensors to be analyzed either sequentially or in parallel.
The biosensor system of the present invention can be constructed and used to detect each of a mixture of target nucleic acids (for example, Chlamydia and Gonorrhea in urogenital infections or E. coli and Salmonella during food processing). This may be done by using a plurality of fluorophores (which, for example, fluoresce at different wavelengths), each of which is tethered to an immobilized nucleic acid probe that is characteristic of or specific for detection of a given species or strain. In this example, the observed wavelength(s) of fluorescence emission will then be specific for hybridization of a given target nucleic acid to its complementary immobilized probe.
The biosensors of the present invention have an improved detection limit and sensitivity with respect to the prior art and are shown to be stable over prolonged storage and severe washing and sterilization conditions. Sensors stored over 1 year in vacuo, in 1:1 ethanol/water solutions, absolute ethanol, or dry at −20° C. provide identical response characteristics to those freshly prepared. Adsorbed fluorescent contaminants accumulated through storage can be removed (as confirmed through fluorescence microscopy investigations) by sonicating the biosensors in 1:1 ethanol/water where the sensitivity of the device has consistently been observed to increase by a factor of c.a. 2.5 from this pre-treatment with respect to that of freshly prepared biosensors not cleaned before use. Unlike those of the prior art (e.g. Abel et al.), the optical biosensors of the present invention have also shown to be thermally stable wherein device function is maintained after sterilization by autoclaving (20 minutes, 120° C., 4 atmospheres over-pressure). The ability to clean and sterilize a biosensor device so that it may be usable in an on-line configuration and/or in clinical applications is a significant advantage yet realized only by the technology reported herein. Biosensors of this invention also allow for more rapid sample analysis with improved response time for signal generation.
The present invention also provides a recyclable or disposable biosensor for detecting a target nucleic acid, which biosensor includes an optical element for receiving and conveying light to an interaction surface of the optical element and nucleic acid, for a particular nucleic acid sequence which is complementary to the target nucleic acid, immobilized onto the interaction surface of the optical element. The recyclable or disposable biosensor preferably comprises an optical waveguide, which preferably conveys the light by total internal reflection to the interaction surface of the optical waveguide when the organic coating is of equal or higher refractive index in comparison to the surface of the waveguide. The optical waveguide preferably comprises an optical fiber. Fluorescent molecules are provided in a solution in which the recyclable or disposable biosensor is immersed that will bind upon hybridization of the immobilized nucleic acid with complementary target nucleic acid and fluoresce when stimulated by light. Alternatively, the fluorescent molecules are provided bound by a tether to the immobilized nucleic acid.
The present invention provides biosensors for direct analysis of nucleic acid hybridization by use of an optical substrate such as an optical wafer or an optical fiber, and nucleic acids or nucleic acid analogs which have been immobilized onto the optical substrate. Generation of a fluorescence signal upon hybridization to complementary nucleic acids and nucleic acid analogs in a sample may be achieved in a number of different ways. Biosensors of this invention are sufficiently sensitive to directly detect very small quantities of target nucleic acids in a sample without the need to employ nucleic acid amplification methods such as PCR techniques. Biosensors of this invention can have detection limits for target nucleic acids below 10 8 molecules.
The optical biosensor comprises nucleic acid strands or nucleic acid analogs of a specific selected sequence immobilized onto activated optical supports. The selected immobilized sequences are capable of binding to target sequences, including sequences characteristic of and selective for viruses, bacteria, or other microorganisms as well as of genetic disorders or other conditions. Biosensors having such characteristic or selective immobilized sequences are useful for the rapid screening of genetic disorders, viruses, pathogenic bacteria and in biotechnology applications such as the monitoring of cell cultures and gene expression. One important avenue which has been widely ignored by the nucleic acid biosensor community is the investigation of multi-stranded (≧3) nucleic acid formation. For example, triple-helical oligonucleotides have been reported to offer potential use as: sequence-specific artificial nucleases ({a} Moser, H. E.; Dervan, P. B. Science , 1987, 238, 645. {b} Strobel, S. A.; Doucettestamm, L. A.; Riba, L.; Housman, D. E.; Dervan, P. B. Science , 1991, 254, 1639.), DNA-binding protein modulators/gene expression regulators ({a} Cooney, M.; Czernuszewicz, Postel, E. H.; Flint, S. J.; Hogan, M. E. Science , 1988, 241, 456. {b} Durland, R. H.; Kessler, D. J., Gunnel, S., Duvic, M.; Pettit, B. M.; Hogan, M. E.; Biochem ., 1991, 30, 9246. {c} Maher, L. J.; Dervan, P. B.; Wold, B.; Biochemistry , 1992, 31, 70. {d} Maher, L. J. BioEssays , 1992, 14, 807. {e} Maher, L. J. Biochemistry , 1992, 31, 7587. {f} Duvalvalentin, G.; Thoung, N. T.; Hélène, C. Proc. Nat. Acad. Sci. USA , 1992, 89, 504. {g} Lu, G.; Ferl, R. J. Int. J. Biochem ., 1993, 25, 1529.), materials for genomic mapping ({a} Ito, T., Smith, C. L.; Cantor, C. R. Proc. Natl. Acad. Sci. U.S.A ., 1992, 89, 495. {b} Ito, T., Smith, C. L.; Cantor, C. R. Nucleic Acids Res . 1992, 20, 3524.), and highly selective screening reagents to detect mutations within duplex DNA (Wang, S. H., Friedman, A. E., Kool, E. T. (1995) Biochemistry 34, 9774-9784.). The present invention can also be used to detect the formation of multi-stranded nucleic acid hybrids (for example, formation triple-helical nucleic acids), and therefore could, for example, operate to monitor the effectiveness, dose dependence and intracellular concentration of nucleic acid pharmaceuticals used in gene therapy applications or as an assay to identify multi-strand formation associated with any of the aforementioned potential applications associated with triple-helical oligonucleotides.
The invention is a biosensor system for detecting a target nucleic acid, which consists of at least three layers, two of which are a waveguide, wherein one layer includes a nucleic acid or nucleic acid analog capable of hybridizing to the target nucleic acid, and wherein a fluorophore is tethered to the nucleic acid or nucleic acid analog and wherein the biosensor functions according to direct excitation. The invention also relates to a biosensor for detecting a target nucleic acid, which comprises an inner layer, a middle layer and an outer layer, wherein
the inner layer has refractive index n 1 ,
the middle layer includes a nucleic acid or nucleic acid analog capable of hybridizing to the target nucleic acid and has refractive index n 2 , which is greater than or equal to refractive index n 1 , and
the outer layer has refractive index n 3 which is less than refractive index n 2 .
and wherein a fluorophore is tethered to the nucleic acid or nucleic acid analog of the middle layer and wherein the biosensor functions according to direct excitation.
In a preferred embodiment, the inner layer is an optical fiber or optical wafer and the outer layer is an ambient. The outer layer is an aqueous based solution. The biosensor is useful for detection of triplex formation or multi-stranded nucleic acid formation. The triplex formation preferably involves a branched antisense nucleic acid which inhibits expression of a target nucleic acid sequence by triplex formation with the sequence.
The biosensor is useful for detection of nucleic acids of bacteria, viruses, fungi, unicellular or multicellular organisms or for the screening of nucleic acids of cells, cellular homogenates, tissues or organs.
Preferably, a fluorophore is tethered to a nucleic acid or nucleic acid analog which is one of the layers of a biosensor having at least three layers and the biosensor functions according to direct excitation. The invention also includes the use of a fluorophore for detecting a target nucleic acid.
The invention also relates to a method of detecting a target nucleic acid, comprising:
pre-treating a sample so that target nucleic acids characteristic of or selective for said sample are available for hybridization;
contacting the sample with the middle layer of the biosensor of claim 2 , such that the target nucleic acids can hybridize to the nucleic acids or nucleic acid analogs of the middle layer;
allowing the fluorophore tethered to the nucleic acids of the middle layer to bind upon hybridization of the target nucleic acids with the nucleic acids or nucleic analogs of the second layer;
illuminating the fluorescent molecules with light such that fluorescence is stimulated; and
detecting the emitted fluorescence, whereby the presence of the target nucleic acid is detected.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 ( a ). Synthetic scheme of Arnold et al. used to activate the glass or fused silica surfaces with long chain aliphatic spacer molecules terminated with 5′-O-dimethoxytrityl-2′-deoxythymidine.
FIG. 1 ( b ). Synthetic scheme of Brennan et al. used to create alkylamine substrate linker molecules on hydroxylated fused silica surfaces.
FIG. 1 ( c ). Synthetic scheme of Maskos and Southern used to functionalize hydroxylated fused silica surfaces with GOPS followed by extension with HEG.
FIG. 1 ( d ). Possible closed loop structure formation as a consequence of the synthesis scheme used in FIG. 1 ( c ).
FIG. 1 ( e ). Synthetic scheme used to extend GOPS functionalized substrates with DMT-HEG via a base catalyzed mechanism.
FIG. 1 ( f ). Synthetic scheme used to covalently link DMT-HEG onto hydroxylated fused silica surfaces via activation with methanesulfonyl chloride.
FIG. 2 . The phenoxyacetyl protecting group used for exocyclic amine (R) protection on nucleoside phosphoramidite synthons.
FIG. 3 ( a ). Synthetic scheme used to create a hydrocarbon-tethered analogue of Ethidium Bromide.
FIG. 3 ( b ). Synthetic scheme used to create a polyether-tethered phosphoramidite analogue of Ethidium Bromide.
FIG. 3 ( b ). Synthetic scheme used to create a polyether-tethered analogue of the bis-intercalative fluorescent probe YOYO-1. Removal of the DMT protecting group followed by treatment with β-cyanoethyl-N,N-diisopropyl phosphityl chloride will yield the tethered YOYO-1 phosphoramidite synthon.
FIG. 4 ( a ). Schematic diagram of one embodiment of an apparatus used to measure fluorescence intensity from optical fibers coated with immobilized DNA.
FIG. 4 ( b ). Schematic diagram an example of a dedicated instrument for analysis of nucleic acid samples by the fiber-optic nucleic acid biosensor of the present invention.
FIG. 4 ( c ). Schematic representation of a biosensor system in which light from a suitable source is directed through a dichroic mirror beam splitter and focused onto a fiber or waveguide coupler and then into an optical fiber having single-stranded nucleic acid bound to the surface thereof, and in which any resultant fluorescent light travels back through the coupler, and passes through the beam splitter and is directed to a photomultiplier detector.
FIG. 5 . Illustration of the operating principles of the fiber-optic nucleic acid biosensor. Hybridization of complement single-stranded oligonucleotide from solution with immobilized nucleic acid probe on biosensor is followed by intercalation of the tethered fluorescent ligand which provides transduction of the selective binding process into a measurable analytical signal.
FIG. 6 . Fluorescent intensity as a function of temperature for the mixed base sequence icosanucleotide functionalized fibers. Upper Curve: response of the optical sensor to 20 pmol of linear complement icosanucleotide in the presence of 2.5×10 −8 M ethidium bromide. Lower Curve: response of the optical sensor to 2.5×10 −8 M ethidium bromide.
FIG. 7 . ( a ) A Model of parallel (T*AT) triplex formation using dT 10 and an optical biosens or functionalized with immobilized dA 10 . dT 10 :dA 10 duplex is first formed upon cooling the system below the duplex T m followed by formation of the triple-stranded complex with further cooling below the T m for triplex formation. (b) The dA 10 of the optical sensor capturing the branched “V” compound 1 (see FIG. 15 ). Note how the fluorescent probe is excluded from the triplex as the temperature is cooled.
FIG. 8 . Quantity of trityl cation released during each detritylation step of the automated phosphoramidite synthesis of dT 20 onto fused silica optical fibers functionalized by the protocols of examples 1 and 5.
FIG. 9 ( a ). Response characteristics of an optical biosensor to complement and non-complement DNA.
FIG. 9 ( b ). Response characteristics of an optical biosensor to 570 ng·ml −1 of complement RNA.
FIG. 10 . Response time of the optical sensor constructed as per the protocols in examples 1 and 5 and effect of ethidium bromide incubation time.
FIG. 11 . Response of a DNA optical biosensor (a) after storage for one month used without cleaning and (b) after storage for eleven months and cleaned by sonication in ethanol for 10 minutes. Note: A 1-month-old sensor which had been cleaned by sonication (data not shown) provided a response similar to (b).
FIG. 12 . Thermal denaturation profiles of aqueous dA 2 +dT 20 and immobilized dT 20 with aqueous dA 20 .
FIG. 13 . Response of the optical sensor with immobilized nucleic acid probe for Candida albicans to complement DNA.
FIG. 14 . Response of a reagentless biosensor as described in Example 14. The graph measures fluorescence from the tethered dye on the terminus of the immobilized nucleic acid as a function of time after exposure to a sample of 720 ng of cDNA.
FIG. 15 . The structures of dT 10 and compound 1, a branched oligonucleotide with identical oligo(thymidine) chains linked to the 2′- and 3′-positions of a ribose branch-point nucleoside i.e., rA 3′→5′-dT10 2′→5′-dT10 binds to dA 10 to yield a triple-stranded complex containing only T•AT (reverse Hoogsteen·Watson/Crick) base triplets.
FIG. 16 ( a ). Response (•) of the optical sensor with a 5′-end terminated recognition sequence to 40 pmol of linear dT 10 in the presence of 2.5×10 −8 M ethidium bromide. Response (X) of the optical sensor to 2.5×10 −8 M ethidium bromide and no dT 10 . ··· Melting profile of the same nucleic acid system in bulk solution by measurement of absorbance (260 nm) in 10 mM TRIS and 50 mM MgCl 2 at pH 7.3.
FIG. 16 ( b ). Response (•) of the optical sensor with a 3′-end terminated recognition sequence to 40 pmol of linear dT 10 in the presence of 2.5×10 −8 M ethidium bromide. Response (X) of the optical sensor to 2.5×10 −8 M ethidium bromide and no dT 10 . ··· Melting profile of the same nucleic acid system in bulk solution by measurement of absorbance (260 nm) in 10 mM TRIS and 50 mM MgCl 2 at pH 7.3.
FIG. 16 ( c ). Response (•) of the optical sensor with a 3′-end terminated Recognition Sequence to 40 pmol of 1 (see FIG. 15) in the presence of 2.5×10 −8 M ethidium bromide. Response (X) of the optical sensor to 2.5×10 −8 M ethidium bromide with no 1. ··· Melting profile of the same nucleic acid system in bulk solution by measurement of absorbance (260 nm) in 10 mM TRIS and 50 mM MgCl 2 at pH 7.3.
FIG. 17 ( a ). Photograph of a UV-shadowed native polyacrylamide gel containing single strands, duplex and triple helical complexes of branched and linear controls. DNA samples were loaded in 50 mM MgCl 2 , and 30% sucrose. Lanes 4-10 are dT 10 , dT 10 :dA 10 (1:1),. dT 10 :dA 10 (2.5:1), dT 10 :dA 10 (4:1), dA 10 , 1+dA 10 , and 1, respectively. As can be noted the dT 10 :dA 10 triplex (lane 7) showed a greater retardation in the mobility relative to the corresponding duplex (lanes 5 and 6). The slowest mobility was observed in lane 9 for 1: dA 10 . Note: See FIG. 15 for the structure of 1.
FIG. 17 ( b ). Photograph of an ethidium bromide stained native polyacrylamide gel (same gel as FIG. 17 { a }) containing single strands, duplex and triple helical complexes of branched and linear controls. DNA samples were loaded in 50 mM MgCl 2 , and 30% sucrose. Lanes 4-10 are dT 10 , dT 10 :dA 10 (1:1), dT 10 :dA 10 (2.5:1), dT 10 :dA 10 (4:1), dA 10 , 1+dA 10 , and 1, respectively. As can be noted the dT 10 :dA 10 triplex (lane 7) showed a slight retardation in the mobility relative to the corresponding duplex (lanes 5 and 6). The slowest mobility was observed in lane 9 for 1: dA 10 . Notice that only the duplexes and triplexes showed ethidium bromide fluorescence. Note: See FIG. 15 for the structure of 1.
FIG. 18 . Schematic diagram illustrating the experimental concept for light scattering investigations of a two-layer system with n Fused Silica >n Film .
FIG. 19 . Schematic diagram illustrating the experimental concept for light scattering investigations of a three-layer system with n fused Silica >n Film >n Ambient .
FIG. 20 . Schematic diagram illustrating the experimental concept for light scattering investigations of a three-layer system with n Fused Silica <n Fim >n Ambient .
FIG. 21 . Schematic diagram of the instrument used for investigations of angularly dependent light scatter.
FIG. 22 . Control experiments for the Angularly Dependent Light Scattering Technique Using Substances of Known Refractive Index.
FIG. 23 . Results of the light scattering experiments done with substrates coated with a thin organic films.
FIG. 24 . Results of the light scattering experiments done with substrates coated with covalently immobilized oligonucleotides.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to a biosensor which functions according to an intrinsic mode of operation. Using the chemistries as disclosed in this patent application) for attaching linker molecules onto optical waveguide supports (preferably optical fibers) and an automated DNA synthesizer, control over the orientation and a wide range of oligonucleotide packing densities on the waveguide is afforded. In this way, immobilized films of oligonucleotides of desired refractive index may be constructed on waveguide supports so that the oligonucleotide film is made to be an extension of the waveguide. This intrinsic mode of operation provides a highly efficient means of signal generation and collection where fluorescence excitation and emission occur within the waveguide itself, providing an expected enhancement in sensitivity and lowering of detection limits by six orders of magnitude.
The second major improvement provided by our technology is the use of fluorescent dyes tethered to or otherwise associated with the immobilized oligonucleotide. Thompson and Krull ({a} M. Thompson and U. J. Krull, Trends in Analytical Chemistry , 3 (1984) 173-178. {b} M. Thompson and U. J. Krull, Analytical Chemistry , 63 (1991) 393A-405A.) teach that biosensors may be defined as devices which consists of a biorecognition element and a transduction element. The biorecognition element may be a biological material capable of participating in highly selective binding to a target, usually a biologically significant molecule. The transduction element converts the selective binding reaction into a measurable analytical signal. The transduction strategy of Gerdt is too non-selective for the technology to be classified as a biosensor whereas the devices of Fodor, Squirrell, Abel et al., Sutherland et al. and Hirschfeld do not contain a transduction element at all. In addition to the requirement for external reagent treatment, in the cases of Fodor, Sutherland et al., and Hirschfeld, there also exists the extra shortcoming that all intercalant dyes are known or suspected mutagens. Therefore, the troublesome issues of collection and disposal of hazardous chemical waste exists subsequent to each analysis. By associating the transduction element with the biorecognition element, the device may function without the need for external reagent treatment and obviated the need to collect and dispose of hazardous waste. Such a technology then readily lends itself to automated and in-line analysis and precludes the need for skilled technicians to partake in the analysis procedure or disposal of waste (provided the sample itself is not biohazardous).
The other advantage provided by the incorporated dye is internal calibration. More specifically, three key advantages may be realized: 1) the associated dye provides a means to determine the quantity of fluorophore and immobilized nucleic acid on the waveguide; 2) the fluorophore in the presence of single-stranded nucleic acid provides a baseline signal to which all signals can be referenced, hence providing meaningful analytical data; and 3) the useful lifetime of the device can be determined from alterations in the background fluorescence signal from the incorporated fluorophore over time. Therefore, by including the associated fluorescence transduction unit, an internal reference marker and diagnostic tool for the device status is included as an integral part of the optical biosensor.
Nucleic acid oligomers are covalently immobilized onto optical fibers by first activating the surface of the optical fiber with a long chain spacer arm terminated by a chemically protected terminus, normally a dimethoxytrityl (DMT) moiety, followed by automated solid-phase DNA synthesis. Detection of nucleic acids or nucleic acid analogs at the fiber surface after hybridization between immobilized nucleic acid and its complementary nucleic acid is achieved by measuring enhanced fluorescence emission of the fluorophore.
The optical fiber may be activated with a number of different compounds. The method of Arnold and co-workers (Arnold et al., 1989 , Collect Czech. Chem. Commun ., 54: 523) may be used for the activation of the fused silica wafers, optical waveguides, and optical fibers whereby 25 atom-long spacer molecules terminated by a dimethoxytrityl protected nucleoside are immobilized onto the cleaned optical fiber substrate, as illustrated in FIG. 1 ( a ). In this method, the length of the spacer between the substrate and the first nucleoside is sufficiently long so that the environment of the terminal nucleoside is fluid enough to permit efficient coupling with successive nucleotide monomers during automated phosphoramidite synthesis of the immobilized nucleic acid probe. This is in accord with the report of Beaucage et al. (1992, Tetrahedron, 48: 2223-2311) wherein it was stated that substrate linkers of lengths of at least 25 atoms are required to achieve high (≧99.5%) synthon coupling yields. The synthetic scheme of Arnold et al. requires inexpensive chemicals, is facile to perform, and is done as a one pot procedure wherein product isolation and purification is obviated. Because the linker is terminated by a protected nucleoside, any reactive sites on the support which would lead to the production of unwanted side products during automated synthesis can be eliminated by treating the derivatized supports with acetic anhydride prior to synthesis. Lastly, the coverage of linker on the support is easily determined by determining the amount of trityl cation released during the first trichloroacetic (TCA) deprotection step of the automated synthesis. This methodology does however place limits on the types of nucleobase protecting chemistries can be used as treatment with strong base will cleave the succinate bond between the substrate linker and the oligonucleotide probe.
An amine-terminated solid support suitable for automated oligonucleotide synthesis may be prepared according to the method of Brennan et al. (1993, Sensors and Actuators B, 11: 109). A bifunctional amphiphilic support derivatization agent is created by condensing γ-aminopropyltriethoxysilane (APTES) with 12-nitrododecanoic acid. The resulting long chain spacer molecule is covalently immobilized onto the surface of the optical fibers by an S n 2 reaction between the hydroxyl groups present at the surface of the fiber and the silane moiety of the amphiphile. With the terminus of the substrate linker in the non-reactive nitro-form, the support may then be capped using standard methods employed during automated synthesis (acetic anhydride), or with chlorotrimethylsilane (R. T. Pon Methods in Molecular Biology , Vol.20: Protocols for Oligonucleotides and Analogs, S. Agrawa, Ed, 1993, Humana Press, Inc. Totowa N.J.), thereby masking other sites of reaction which may produce unwanted side products during oligonucleotide synthesis. Reduction of the terminal nitro-functionalities is then achieved by treatment of the derivatized support with an acidic zinc solution. The resulting amine headgroups may then be used directly for automated synthesis wherein an ammonolysis/base resistant phosphoramidate linkage is made between the activated support and the first nucleotide. An outline of a synthetic procedure used to immobilize alkyl amine monolayers covalently onto fused silica substrates is depicted in FIG. 1 ( b ).
The hydrolysis resistant linkage of Maskos and Southern may also be employed to provide waveguides functionalized with substrate linkers. Analogous to the natural internucleotidic linkage, a phosphodiester linkage between the substrate linker and first nucleotide is completely resistant to ammonolysis under the conditions which remove standard base-protecting groups. This linkage is produced by derivatization of optical fibers with the bifunctional silylating reagent 3-glycidoxypropyltrimethoxy silane via silyl-ether bond formation with the hydroxylated waveguide surface. This yields a substrate derivatized with short spacer molecules with terminal epoxide moieties. The length of the spacer arm is then extended by nucleophilic attack of a polyether, such as hexaethylene glycol (HEG), in an acid catalyzed expoxide ring-opening reaction, yielding a stable ether linkage (U. Maskos and E. M. Southern, 1992 Nucl. Acids Res ., 20(7). 1679), as shown in FIG. 1 ( c ). Polyether chains provide for hydration, flexibility for molecular motion, and improved biocompatibility in terms of minimization of non-selective binding to biological compounds. By extending the spacer molecule ensemble to one composed of at least 25 atoms, optimal phosphoramidite synthon coupling efficiencies are realized (Beaucage et al., 1992 Tetrahedron , 1992 48, 2223). This support, terminated with a hydroxyl functionality, is then used directly for automated oligonucleotide synthesis, obviating the need for tedious nucleotide functionalization of the support.
Since polyethylene glycols are bifunctional, there exists the possibility of creating non-reactive closed-loop structures which may significantly decrease the amount of loading of oligonucleotides on the surface of an optical fiber, as shown in FIG. 1 ( d ). To eliminate any such problem and improve upon the prior art, one terminus of the polyether is protected with a suitable blocking group, for example, with a DMT functionality, prior to extension of the glycidoxypropyltrimethyl silane. In the case where a chromophoric protecting group is used (such as DMT), an additional advantage is provided wherein facile determination of the amount of support linkers may be determined by monitoring the absorbance of the deprotection solution (e.g. 504 nm for DMT + ). Mono-dimethoxytrityl protected polyethylene glycols may be introduced onto the surface of fused silica waveguides by a number of methods. Waveguides first functionalized with GOPS, as in the method of Maskos and Southern, may then be treated with a solution of mono-dimethoxytritylated polyethylene glycol over sodium hydride to afford linkage of the polyether to the terminal epoxide moiety of the immobilized GOPS via a base catalyzed epoxide ring-opening reaction as shown in FIG. 1 ( e ). Mono-dimethoxytritylated polyethylene glycols (such as DMT-HEG) can also be directly linked to the surface of fused silica waveguides by activation of the terminal hydroxyl moiety of the polyether with methane sulfonyl chloride or β-cyanoethyl N,N-diisopropyl phosphityl chloride, as shown in FIGS. 1 ( e ) and 1 ( f ), respectively. In the later case, the polyether substrate linker is attached as a phosphoramidite synthon which can be done as part of the automated oligonucleotide synthesis procedure; thereby making the entire biosensor fabrication protocol completely automated after cleaned waveguide pieces are introduced into the synthesis column of the automated synthesizer.
The biorecognition element to be bound onto the terminus of the substrate linker in configuration of the described biosensor can include immobilized nucleic acids (DNA and RNA), modified nucleic acids, and nucleic acid analogs prepared by well-known methods or by straight-forward extension or modification of those methods. The term nucleic acid includes polynucleotides, oligomers, relatively short polynucleotides (up to about 50 bases), longer polynucleotides ranging up to several hundred bases, and doubled-stranded polynucleotides. There is no specific size limit on nucleic acids used for immobilization in this invention. However, problems due to self-hybridization and reduced selectivity may occur with longer nucleic acids. As used herein, the term “nucleic acid analogs” includes modified nucleic acids. As used herein, the term “nucleotide analog” includes nucleic acids where the internucleotide phosphodiester bond of DNA or RNA is modified to enhance bio-stability of the oligomer and “tune” the selectivity/specificity for target molecules (Ulhmann, et al, 1990 , Angew. Chem. Int. Ed. Eng ., 90: 543; Goodchild, 1990, J. Bioconjugate Chem., I: 165; Englisch et al, 1991, Angew, Chem. Int. Ed. Eng., 30: 613). Such modifications may include and are not limited to phosphorothioates, phosphorodithioates, phosphotriesters, phosphoramidates or methylphosphonates.
In the present invention, nucleic acid sequences are covalently attached to the surface of the optical fiber. In a preferred embodiment, an automated DNA synthesizer is used to grow nucleotide oligomers onto the surface of activated optical fibers via the well established β-cyanoethylphosphoramidite method. Any commercially available automated DNA synthesizer can be used. The use of an automated synthesizer to grow nucleic acids or nucleic acid analogs on the optical fiber substrates provides many advantages over conventional techniques of DNA immobilization. Conventionally, nucleic acid strands are adsorbed onto a suitable support (usually nitrocellulose) with little known about strand orientation. The use of an automated oligonucleotide synthesizer provides full control of the oligomer sequence, strand orientation, and packing density in association with activation of the optical fiber substrates. Control over these parameters is critical to the development of a nucleic acid detection method based on hybridization as the alignment of the immobilized strands with respect to the availability of target nucleotides for hybridization and intermolecular interactions (electrostatic and steric) between oligomers will have direct ramifications on the kinetics and thermodynamics of hybrid formation and dissociation. The use of a gene machine, in addition to the chemistry used to activate the surface of the optical fibers, allows for the creation of membranes of desired density and structural order to permit rapid and reversible hybridization, and to control refractive index.
The use of the phosphoramidite method of oligonucleotide synthesis has been widely reviewed and has become the synthetic method of choice owing to the high coupling efficiencies and robustness of the reagents, in addition to the fact that the necessity of numerous product isolation and purification steps (which are required for liquid phase methods) are avoided. There are two readily available types of phosphoramidites which may be used to synthetically grow oligonucleotides, namely, methylphosphoramidites and β-cyanoethylphosphoramidites. The method utilizing β-cyanoethyl phosphoramidites is preferable as complete deprotection of the oligonucleotides can be done using aqueous ammonia (as opposed to thiophenol) for the case where oligonucleotides were grown onto controlled pore glass (CPG). Triethylamine is used to deprotect the β-cyanoethyl protected oligonucleotides grown onto fused silica wafers or optical fibers without liberating the oligonucleotides from the support. An overview of the β-cyanoethylphosphoramidite synthesis is as follows:
The first step in each cycle of solid phase automated phosphoramidite synthesis involves the removal of the dimethoxytrityl protecting group on the immobilized nucleotide. Detritylation is done by introducing a solution of 3% trichloroacetic acid (TCA) in 1,2 dichloroethane (DCE) onto the synthesis column in order to yield a 5′-hydroxyl functionality onto which the next nucleotide monomer may be coupled. TCA is the reagent of choice for detritylation due to its rapid reaction rate so that the oligonucleotide is only exposed to the acid for short periods of time, thereby avoiding the acid catalyzed removal of the adenine and guanine moieties from the nucleotide sugar groups by the process of depurination. Once the reaction has been completed, the acid is removed by flushing the column with acetonitrile. The eluent containing the released trityl cation is sent to a fraction collector so that the coupling efficiency of the synthesis may be monitored by absorption spectroscopy.
Coupling is the next stage of the synthesis cycle. The contents of the synthesis column are dried by alternatively washing with acetonitrile and flushing with dry argon. This ensures that the support is anhydrous and free of nucleophiles. The desired phosphoramidite and tetrazole are then sent into the synthesis column. Tetrazole is a weak acid (pK a =4.8) which is used to activate the phosphoramidite. Nucleophilic attack by the 5′-hydroxyl group on the activated phosphoramidite moiety forms an internucleotide linkage. A ten-fold molar excess of phosphoramidite in an excess of tetrazole is added to the synthesis column to ensure that high coupling yields are achieved.
The next step of the synthesis is the capping step. This is done to eliminate further growth of sequences onto which coupling did not occur. The failed sequences are rendered unreactive by introducing acetic anhydride in the presence of dimethylaminopyridine in order to acetylate any remaining unprotected 5′-hydroxyl moieties.
Because the trivalent internucleotide phosphite moieties are labile to both acidic and basic conditions, a solution of aqueous iodine is added after flushing the capping reagents from the column. This is done in order to oxidize the trivalent internucleotide phosphite moieties to the more stable pentavalent phosphate moieties found in naturally occurring nucleic acids. This procedure is termed the oxidation step.
Following the oxidation step, one cycle of nucleotide addition is complete. The process may be repeated many times until oligonucleotides of desired length and base sequence have been constructed. After addition of the last nucleotide, a final detritylation step is usually done in order to yield a 5′-hydroxyl group on the completed sequence.
Triethylamine is used for the removal of β-cyanoethyl protecting groups on the internucleotidic phosphotriester moieties of oligonucleotides grown onto optical substrates. This procedure is known to cause quantitative loss of the phosphate protecting groups via a β-elimination mechanism while not cleaving the single-stranded nucleic acids from the optical fibers. Ammonia treatment of the immobilized oligonucleotides is avoided by choosing an all-thymine base sequence. Thymine does not contain a primary amine functionality which would require protection during oligonucleotide synthesis. This approach is not limited to the use of phosphoramidite synthons, but is compatible with all commercially available solid-phase synthesis such as the H-phosphonate chemistry (Froehler, B. C., 1986, Tetrahedron Letters, 27: 5575; Stein et al, 1990, Analytical Biochemistry, 188: 11).
Contrary to the conventional preparation of oligonucleotides by solid-phase synthesis, post-synthesis removal of the product from the support is not desired. In order to prevent cleavage of the oligonucleotide from the support (optical fiber) while removing the protecting groups of the nucleobases, two modifications to the usual synthetic protocol can be made. The approach involves the combination of a hydrolysis resistant linkage between the oligomer and support along with the use of labile base protecting groups. Thus, an oligomer of any sequence can be prepared and deprotected yet remain attached to the support, available for hybridization.
The phenoxyacetyl (PAC) family of protecting groups represents a convenient method for blocking the exocyclic amino functions of guanine, adenine and cytosine residues (thymine or uracil require no nucleobase protection). The half-time of deprotection with concentrated ammonium hydroxide at 20° C. is 8 min, 7 min and 2 min, respectively (Wu et al, 1989). Under these conditions, the cyanoethyl phosphate protecting groups are removed within seconds (Letsinger and Ogilvie, 1969), whereas the linkage which joins the oligomer to the surface of the fused silica fiber (e.g., a phosphodiester or phosphoramidate) is completely stable under these conditions. Alternative labile protecting groups are derivatized phenoxyacetyl groups including alkyl substituted PAC groups, more specifically t-butylphenoxyacetyl groups. The t-butylphenoxyacetyl group can be quickly removed compared to hydrolysis of the linkage to the spacer thereby reducing the possibility of cleavage of the immobilized sequence from the surface. N-phenoxyacetyl deoxynucleoside 3′-cyanoethylphosphoramidites and the analogous t-butylphenoxyacetyl phosphoramidites are commercially available. It has been reported by Polushin and Cohen (N. N. Polushin and J. S. Cohen, Nucleic Acids Research, 1994, 22, 5492-5496) that the t-butylphenoxyacetyl nucleobase protecting groups can be quantitatively be removed by treatment with ethanolamine for 10 minutes at room temperature or by treatment with a mixture of hydrazinelethanolamine/MeOH (1:1:5 v/v/v) for 3 minutes. Beaucage and co-workers (J. H. Boal, A. Wilk, N. Harindranath, E. E. Max, T. Kempe and S. L. Beaucage, Nucleic Acids Research, 1996, 24, 3115-3117.) also report the rapid and quantitative removal of t-butylphenoxyacetyl protecting groups by treatment of the support-bound protected nucleic acid with gaseous amines ({a} anhydrous ammonia gas, 10 bar, 25° C., 35 min. or, {b} methylamine, 2.5 bar, 25° C., 2 min.)
Other possible labile protecting groups could include the “FOD” (fast oligonucleotide deprotection available from Applied Biosystems Inc.) based on N,N-dialkylformamidines (Vinayak et al, 1992, Nucleic Acids Research, 20: 1265-1269). Kuijpers et al (Tetrahedron Lett., 1990, 31 6729-6732 and Nucleic Acids Res., 1993, 21, 3493-3500) have described a method of nucleobase protection using 2-(acetoxy-methyl) benzoyl (AMB) moieties which can be removed by treatment with anhydrous potassium carbonate in methanol for 90 minutes at room temperature. Use of protecting groups that can be selectively removed under conditions that will not cleave the oligomer from the support, such as the levulinyl group (removed by hydrazine treatment) (Letsinger et al, 1968, Tetrahedron Letters, 22: 2621-2624; Hassner et al, 1975, J. Amer. Chem. Soc., 97: 1614-1615) are also contemplated by the present invention. Even synthesis without nucleobase protecting groups is possible for nucleic acid oligomers of up to 20 nucleobases in length using the phosphoramidite approach (Gryaznov et al, 1991, J. Amer. Chem. Soc., 113: 5876) or H-phosphonate chemistry (Kung et al, 1992, Tetrahedron Letters, 33: 5869). Any of these approaches circumvents difficulties in removing nucleobase protecting groups while leaving the oligomer attached to the support.
Free short strands of nucleic acids can also be covalently attached to the optical fiber directly or via linker molecules. This approach allows the use of DNA or RNA isolated from natural sources, amplified nucleic acids or their analogs, or synthetic samples provided in the fully deprotected form. Protocols provide end-attached oligomers of a well defined orientation. Chemically stable linkages between the support and oligonucleotide may be employed to enhance the robustness of the biosensor.
Quartz (or interchangeably fused silica) optical fibers derivatized with linker molecules terminated with either hydroxyl or amino groups can serve as substrates for carbodiimide-mediated coupling with terminally phosphorylated single-stranded nucleic acids. Coupling to the hydroxyl fiber produces a phosphodiester bond while coupling to an amine fiber yields a phosphoramidate bond. Oligonucleotides can be phosphorylated, in solution, either chemically via a modification of Ouchi's method (Sowa et al Bull. Chem. Soc., Japan 1975, 48 2084) or enzymatically.
Covalent attachment of free short strands of single-stranded nucleic acid to the optical fibers can be achieved by a slight modification of the method Ghosh and Musso (Ghosh and Musso, 1987, Nucl. Acids Res. 15: 5353). Coupling of a 5′-aminohexyl derivatized oligomer with activated carboxyl fibers affords end-attached oligomers. This method is known to minimize reaction at the amino groups of the DNA bases (which would potentially compromise the hybridization event) and affords surfaces with excellent nucleic acid coverage. The synthesis of the 5′- or 3′-terminally modified oligomers can be achieved readily by standard methods (Ghosh and Musso, 1987; Beaucage and lyer, 1993).
RNA may be assembled on the support or prepared separately and linked to the support post-synthesis. RNA monomers are commercially available, as are some 2′-O-modified synthons. The 2′-O-methyl, allyl and 2′-deoxy-2′-fluoro RNA analogs, when incorporated into an oligomer show increased biostability and stabilization of the RNA/DNA duplex (Lesnik et al, 1993, Biochemistry, 32: 7832).
As used herein, the term “nucleic acid analogs” also include alpha anomers (α-DNA), L-DNA (mirror image DNA), 2′-5′ linked RNA, branched DNA/RNA or chimeras of natural DNA or RNA and the above-modified nucleic acids. Back-bone replaced nucleic acid analogs can also be adapted to use in the biosensor of the present invention.
For purposes of the present invention, the peptide nucleic acids (PNAs) (Nielsen et al, 1993, Anti-Cancer Drug Design, 8: 53; Engels et al, 1992, Angew, Chem. Int. Ed. Eng., 31: 1008) and carbamate-bridged morpholino-type oligonucleotide analogs (Burger, D. R., 1993, J. Clinical Immunoassay, 16: 224; Uhlmann, et al, 1993, Methods in Molecular Biology, 20, “Protocols for Oligonucleotides and Analogs,” ed. Sudhir Agarwal, Humana Press, NJ, U.S.A., pp. 335-389) are also embraced by the term “nucleic acid analog.” Both exhibit sequence-specific binding to DNA with the resulting duplexes being more thermally stable than the natural DNA/DNA duplex. Other back-bone replaced nucleic acids are well-known to those skilled in the art and may also be used in the present invention (See e.g., Uhlmann et al 1993, Methods in Molecular Biology, 20, “Protocols for Oligonucleotides and Analogs,” ed. Sudhir Agrawal, Humana Press, NJ, U.S.A., pp. 335).
Optical substrates such as planar wafers and optical fibers may be used in the present invention. A preferred embodiment utilizes optical fibers. Optical fibers are particularly advantageous as membrane supports due to their small size, high light transmission capability, and ability to allow total internal reflection (TIR) of light. Optical fibers also provide a compact an rugged sensing device, and offer the ability to do remote spectroscopic measurements (Love et al, 1991, Biosensors with Fiberoptics, D. L. Wise and L. B. Wingard (Eds.), Humana, NJ, pp. 139-180).
There are two fundamental configurations in which alterations in fluorescence parameters from fluorescently doped membranes on optical fibers may be monitored, namely, extrinsic mode and intrinsic mode. Extrinsic mode configurations are those in which the waveguide is simply used as a light pipe or conduit. End-on extrinsic mode investigations are usually done using optical fibers. In a biosensor which uses end-on extrinsic mode configurations, the fluorescent dyes and selective chemistry are located on or near the distal end of the fiber. The fiber is used as a light-pipe or conduit, where the excitation or emission radiation is simply guided from the sampling region to the detector. Fluorescence is stimulated by coupling excitation radiation into the near end of a fiber, and emission can be monitored by placing light sensing equipment directly opposite the distal end of the fiber.
Alternatively, the detector is placed at the near end of the fiber as some of the fluorescence may be coupled back into the fiber and totally internally reflected back to the near end. The side-on extrinsic mode approach is typically used for investigations carried out on planar supports, but may also be used for fibers. The immobilized single-strand nucleic acid and fluorophore are placed along the length of the optical fiber waveguidelwafer. The fiber is illuminated by a light source located normal to the length of the fiber and fluorescence emission is also monitored by equipment placed normal to the fiber. Extrinsic configurations provide the advantage that simple and inexpensive equipment, including conventional light sources and detectors, are used (Krull et al, 1991, Fiber Optic Chemical Sensors and Biosensors, Vol. II, O. S. Wolfbeis, Ed., CRC Press, Boca Raton, pp. 315). However, the extrinsic sampling configuration provides poorer sensitivity owing to the short path length and sensitivity to interferents present in the surrounding media. In a preferred embodiment, an intrinsic mode arrangement, based on careful control of refractive index is used to monitor fluorescence emission from the surface of optical fibers.
Fluorophores present at either the surface or just below the surface of the fiber may be excited through the formation of a standing wave electric field which propagates normal to the surface of the fiber upon total internal reflection of radiation in the fiber. The process of TIR occurs when the angle of incidence, θ, at the interface between a fiber of high refractive index, n 1 , and the external medium of lower refractive index, n 2 , is larger than a critical angle, θ c , defined as: Sin θ c = n 2 n 1 ( 1 )
The amplitude of the electric field of the reflecting radiation decreases exponentially as a standing wave into the medium having the lower refractive index. This decaying radiation is referred to as an evanescent wave and can be used to excite fluorophores located near the boundary for TIR. The propagation intensity, I, of the evanescent wave depends on the reflection angle, θ, the wavelength of the transmitted radiation, γ, and a Fresnel transmission factor, T: I = T ( θ ) · exp ( - 2 x d p ) ( 2 )
where x represents distance normal to the boundary for TIR, and d p is the penetration depth which is given by (Krull et al, 1990, Talanta, 37: 801-807): d p = λ 4 π n 1 2 sin 2 ( θ ) - n 2 2 ( 3 )
The penetration depth is defined as the distance at which the intensity of the evanescent field has decayed to 1/e of the intensity at the reflection boundary. Typically, the evanescent wave propagates into a thin zone beyond the surface of a fiber with a penetration depth ranging from about 200 nm to 400 nm for visible light.
Fluorophores within the evanescent wave propagation zone are excited by that evanescent wave to emit fluorescence. Fluorophores further from the interface with the optical fiber will experience lower intensity of light at the excitation frequency and a resultant concomitant decrease in intensity of emitted fluorescence.
A major limitation of the evanescent wave excitation is that less than 0.01% of all of the excitation radiation on a fiber actually leaks beyond the fiber as an evanescent wave, and less that 2% of the fluorescence caused by the evanescent wave is actually recovered back into the fiber for transmission to the detector by total internal reflection (Love et al, 1991, Biosensors with Fiberoptics, D. L. Wise and L. B. Wingard (Eds.), Humana, N.J., pp. 139-180). As such, the evanescent wave mode of excitation and fluorescence signal recovery is very inefficient and not the preferred mode of operation for optical sensor devices.
For the case where the refractive index of the immobilized layer is effectively the same or greater than the index of refraction of the substrate for immobilization (e.g., the silica surface of the optical element) the boundary for TIR effectively becomes the interface between the immobilized layer and the solution. Fluorophores bound to nucleic acid in the immobilized layer are directly exposed to the electromagnetic radiation bound within the waveguide thereby providing a vastly improved excitation efficiency and, as a consequence, emit increased intensity fluorescence. For example, the index of refraction of a monolayer of organic media (n monolayer =1.46 to 1.5; Ducharme et al, 1990, J. Phys. Chem. 94: 1925) is very similar to that of fused silica or fused silica (n quartz =1.46; O'Hanian, H. C. 1985, Physics, W. W Norton & Co. N Y. p. 835). Fluorophores in the immobilized layer then emit fluorescence radiation within the waveguide itself to provide a much improved probability for transmission of the fluorescence signal by total internal reflection to the detector, yeilding increased sensitivity and lower target nucleic acid detection limits.
Fluorescence is the analytical method chosen for the transduction of hybridization events into a measurable analytical signal, since fluorescence techniques have long been known to provide high sensitivity (comparable to radioisotopic methods) and detailed information about structure at the molecular level (Lakowicz, 1983, Principles of Fluorescence Spectroscopy, Plenum Press, NY). Changes in the polarity, pH, temperature, microviscosity, or orientation of molecules in the local environment of a fluorophore may result in alteration of the electronic structure or collisional probabilities of the fluorophore. Such environmental changes may be detected by monitoring fluorescent signal parameters such as intensity, wavelength, lifetime, or polarization. For example, it is not uncommon for the efficiency of fluorescence emission (quantum yield) and fluorescence lifetime of an intercalant fluorophore to increase by an order of magnitude or more when inserted into the rigid and hydrophobic base stacking region of a double-stranded nucleic acids with respect to that of the unbound dye in solution.
The present invention utilizes, and is not limited to, the fluorescence intensity response of the bound fluorophore via monitoring in a total internal reflection configuration along the optical fiber substrate to quantify the presence of hybridized nucleic acids at the surface of the fiber. The fluorescence intensity is directly proportional to the amount of target nucleic acid or nucleic acid analog initially present in solution. It is also possible to use the time dependence of the rate of change of the fluorescence intensity increase upon hybridization to determine the concentration of target nucleic acid.
The fluorophore of the present invention can be for example ethidium bromide (EB). The ethidium cation (3,8-diamino-6-phenyl-5-ethyl-phenanthridium) is a fluorescent compound which strongly associates with double stranded nucleic acids by intercalation into the base-stacking region and, in some cases, the major groove of the double helical structure (Monaco et al., 1993, Journal of Bimolecular Structure and Dynamics, 10: 675). The ethidium cation is particularly well suited for investigations of nucleic acid hybridization for a number of reasons. Firstly, the quantum yield of the dye is known to increase as much as 100-fold when intercalated into the base stacking region with respect to that of the unbound dye in aqueous solution (Bauer et al, 1989, Proceedings of the National Academy of Science USA, 56: 7937). Secondly, the binding affinity and the fluorescence enhancement of the dye are independent of base composition (Cuniberti et al, 1990, Biophysical Chemistry, 38: 11). Thirdly, intercalation of the ethidium cation is known to increase duplex stability as the two 3,8-amino substituents hydrogen bond with the internucleotide phosphate groups on each of the DNA strands (whereas other intercalators are known to significantly decrease duplex stability) (Cuniberti et al, 1990, Biophysical Chemistry, 38: 11). The absorption maximum of ethidium bromide is 510 nm, which is sufficiently close to the output wavelength of 488 nm of an Ar + laser which may be used to excite the fluorophore. The dye has an emission maximum of 595 nm when bound to DNA which is a sufficiently large Stoke's shift to make separation of the emission radiation from the excitation radiation straight forward, and to prevent inner filter effects, by the use of a dichroic mirror or other standard optical components (Haugland, 1992, Molecular Probes: Handbook of Fluorescent Probes and Research Chemicals, 5th Ed:, USA: Molecular Probes Inc.). Due to the above mentioned reasons, the use of EB has been shown to provide a sensitive means to detect the presence of nucleic acid duplexes for this application.
A specific example of a tethered fluorophore is illustrated in the synthetic schemes of FIG. 3 a,b , and c . In this case a modified ethidium-type dye with tether, here C 13 acid moiety, is synthesized as shown (FIG. 3 a ). The ethidium analogue with acid tether is attached to 5′-hexylamine functionalized oligonucleotides immobilized on the surface of an optical fiber to generate the biosensor with the tethered fluorophore probe. For the case where the nucleotides are grown on the support via solid phase phosphoramidite synthesis, the 5′-hexylamine functionalization can readily be achieved through the use of the commercially available reagent Aminolink 2®.
The fluorophore or reporter group may be attached to the 5′- or 3′-end of the oligomer by not only a hydrocarbon tether but other types of tethers such as polyether, mixed aliphatic/aromatic, or peptidic. The tether need not be restricted to the 3′- or 5′-ends of the oligomer but may be attached to a terminal or internal ribo-residue via the 2′-hydroxyl (Yamana et al, 1991, Tetrahedron Letters, 32: 6347). Similarly, a tether can be attached to a terminal or internal nucleobase using pyrimidines (Pieles et al, 1990, Nucleic Acids Research, 18: 4355) or purines (Roduit et al, 1987, Nucleosides and Nucleotides, 6: 349). Furthermore, the internucleotidic linkage can be a site for tether attachment (Agrawal et al, 1990, Nucleic Acids Research, 18: 5419). Obviously, any combination of these methods could be used to site specifically incorporate multiple reporter groups.
The choice of fluorophores which may be tethered to the oligonucleotide include organic intercalating complexes, such as the commonly used nucleic acid stain ethidium bromide, thiazole orange and analogs thereof as prepared by L. G. Lee et al (1986, Cytometry 7: 508) and the YOYO, BOBO, and TOTO series of cyanine based intercalant fluorophores which are commercially available from Molecular Probes Inc. (Eugene, Ore.). Inorganic coordination complexes, such as the “molecular light switch” Ru(phen') 2 dppz PF 6 developed by Jenkins et al. (1992, J. Amer. Chem. Soc. 114: 8736) may also be used as well as groove binding dyes, such as Hoechst 33258 and Hoechst 33342, which are commercially available from Aldrich Chemical Co. (Milwaukee, Wis.). These fluorophores are chosen such that the fluorescent probe is quenched (non-emissive) when in the presence of single-stranded nucleic acids and provides intense luminescence when in the presence of double stranded nucleic acids. This change in observed luminescence occurs via changes in the relative rates of radiative and non-radiative relaxation processes of the probe when the external environment changes from aqueous solution to a hydrophobic and highly structured one in the base stacking region of double-stranded nucleic acids.
Other examples of classes of fluorophores which can be used in the present invention include acridine dyes, phenanthrides, phenazines, phenothiazines, quinolines, alfatoxin, polycyclic hydrocarbons, oxirane derivatives, actinomyces, anthracyclinones, thiaxanthenones, anthramycin, mitomycin, platinum complexes, polyintercalators, norphilin-A, fluorenes and fluorenones, furocoumarins, benzodipyrones and monostral fast blue. Preferred dyes are also those that provide large Stoke's shifts, can be excited at long wavelengths and have large differences in fluorescence lifetime, quantum efficiency, and/or wavelength of excitation and emission when in solution as compared to when bound to hybridized nucleic acids.
Light emitted from fluorophores (after direct excitation) at the surface of the fiber is preferentially coupled back into the fiber and can be monitored by a photomultiplier tube (PMT) or any other suitable light detection equipment. Increasing the length of coated fiber results in a greater optical path length and better sensitivity (Krull et al, 1991, Fiber Optic Chemical Sensors and Biosensors, Vol. II, O. S. Wolfbeis, Ed. , CRC Press, Boca Raton, pp. 315). Direct excitation of fluorophores in an immobilized layer extending from the biosensor results in improved signal to noise ratio as interferences from background fluorescence in the bulk environment are avoided.
One instrument used for fluorescence intensity measurements is based on a fluorescence microscope as described elsewhere (Brennan et al, 1990, Anal, Chim. Acta., 237: 253) and shown in FIG. 4 ( a ). An instrument as shown in FIG. 4 ( b ) may also be used in which the output from a suitable light source, for example an argon ion laser, is directed into an optical fiber via a lens with a numerical aperture which is equal to or greater than the numerical aperture of the nucleic acid functionalized waveguide when in the hybridization buffer solution used for analyte detection. The excitation radiation may be coupled into a delivery fiber via a twisted optical fiber waveguide assembly such that all modes carried by the first fiber into which the excitation radiation was first coupled would be delivered to the second fiber to provide optimal excitation of fluorophores associated with the biosensor. The excitation radiation may be totally internally reflected along the length of the delivery fiber to a sensing fiber functionalized with immobilized oligonucleotide and fluorophore. Coupling of the radiation between fibers may be achieved by abutting the distal terminus of the delivery fiber to the proximal terminus of the sensing fiber in a suitable non-fluorescent fiber coupler. The terminus of the coupler is preferentially designed as a compression-fit end which provides a solution-tight seal to prevent contaminants from diffusing into the fiber coupler and causing drift in the analytical signal. The sensing fiber is situated within in a small volume, stop-flow, hybridization chamber made of a suitable inert material with good thermal conductivity (e.g. stainless steel or titanium). The temperature of the hybridization may be controlled by use of a suitable thermoelectric housing to provide rapid thermostating to the desired temperature and computer control. The temperature of the solutions in the hybridization cell may be accurately determined (±0.2° C.) by use of a glass encapsulated thermistor incorporated into the hybridization cell. Solutions delivery to the hybridization cell and sensing fiber may be done by use of a computer controlled pump (e.g. peristaltic pump) where all solutions originate from a computer controlled autosampler. Fluorescence emission from fluorophores associated with immobilized nucleic acid complexes was totally internally reflected within the sensing fiber. The portion of the light coupled back into the delivery fiber was directed towards an interference filter with the appropriate bandpass window for the emission of the fluorophore used with the optical sensor. Fluorescence radiation traversing the interference filter then enters a photomultiplier tube to provide a quantitative measure of the fluorescence intensity. In alternative embodiments, the radiation source can be a frequency doubled laser, a semiconductor laser, bright lamp or LED. Coupling into the waveguide can be accomplished with fiber couplers, and the detector can be an avalanche diode rather than a PMT.
In one embodiment of the invention the biosensor operates as follows. The optical fiber with attached fluorescently labeled single-stranded nucleic acid is placed in a flow through cell and immersed in hybridization buffer solution. When single-stranded nucleic acids or nucleic acid analogs which are complementary to the immobilized strands are introduced to the flow cell, hybridization occurs followed by intercalation (or other suitable ligand binding motif) and enhanced fluorescence emission of the attached fluorescent probe, as illustrated in FIG. 5 . Fluorescence intensity is monitored in a total internal reflection configuration wherein the optical fiber and organic coating form a waveguide to provide excitation to the surface immobilized nucleic acid and fluorescent probe, as well as to collect fluorescence emission. By monitoring the fluorescence intensity from the fiber, a measure of the amount of target nucleic acid in solution can be determined.
Regeneration of the biosensor can be achieved by thermal methods such as by elevating the temperature within the flow-through hybridization cell or by chaotropic methods in which solutions of highly polarized salts alter the hydrogen bonding structure of the solution to affect denaturation of the hybridized complex. In either case, the complex stability in the system is reduced to the point where hybridization is not energetically favorable and the complement strands are dissociated from the covalently immobilized oligomers and may be flushed out of the flow cell. Regeneration methods as described herein can be employed to recycle biosensors.
Formation of multi-stranded nucleic acids (i.e. nucleic acid complexes composed of 3 or more strands), such as triplex nucleic acids, may be determined from the temperature dependence of the fluorescent signal. Normally, the fluorescence efficiency of a fluorophore increases with decreasing temperature owing to the reduced collisional deactivation as a consequence of the reduced kinetic energy of the molecules surrounding the fluorophore. Fluorescence efficiencies with negative temperature coefficients are readily observed for fluorophores in solution and well as for fluorophores intercalated into nucleic acids, as illustrated in FIG. 6 . When multi-strand formation occurs, (e.g. binding of a third strand in the major groove of a double-helical nucleic acid) exclusion of the bound ligand often follows as the partition coefficient for the fluorophore in the multi-stranded nucleic acid is often much reduced with respect to that of the same fluorophore in double-stranded nucleic acid. The ligand exclusion process will also show a temperature dependence where reduced ligand binding is observed as the temperature of the system is decreased. As such, a positive temperature coefficient of fluorescence intensity would be observed for fluorophores associated with multi-stranded nucleic acids as increasing amounts of fluorophore become excluded from the highly-structured environment within the nucleic acid complex into bulk solution where the probability for collisional quenching of fluorescence is far greater. A net positive temperature coefficient of fluorescence intensity would then be observed for a fluorescent nucleic acid binding ligand in a multi-stranded nucleic acid. The temperature at which multi-strand formation occurs could also be assayed from the maxima in a fluorescence intensity versus temperature plot where the temperature coefficient changes from negative (for the dye bound in double-stranded nucleic acid) to positive (for the dye being excluded from the multi-stranded nucleic acid complex). This process is illustrated in FIGS. 7 ( a & b ) for triplex formation on the sensor surface with linear and branched nucleic acids.
The biosensor of the present invention provides for rapid clinical testing for viruses (e.g., HIV, T cell lymphotropic virus 1 and 2, hepatitis B and C), and pathogenic bacteria (e.g. E. coli ., Salmonella, Listeria, Chiamydia ssp., Trichomonas vaginalis, Gradenerella vaginitis ) as well as other microorganisms. Detection of genetic disorders (e.g., cystic fibrosis and sickle-cell anemia) and diseases such as cancer is also done with the method and apparatus of the present invention as well as potential therapeutics to treat such diseases (e.g. branched antisense nucleic acids which inhibit expression of targeted nucleic acid sequences via triplex formation with that particular sequence, effectively shielding the genetic information from being read by transcription enzymes).
The biosensor is useful for the monitoring of the in-vivo response of bacteria to an antibiotic treatment to ensure the efficacy of the treatment regime. The physician, based on past experience, chooses both the antibiotic and the dosage to treat a bacterial infection. Samples of the infecting organism would be sent to the laboratory for MIC testing, Minimal Inhibitory Concentration for the lowest concentration of that particular antibiotic necessary to inhibit the growth of the infecting organism. If the MIC of the in-vitro test is less than the dosage given to the patient, the treatment is allowed to continue, otherwise an increased dose and/or a change of antibiotic would be ordered. The most significant problem of this approach is that of the time required, wherein 1 to 3 days are needed to acquire the MIC result. Secondarily, it is a test of an in-vitro response to reflect an in-vivo situation. Using larger doses than necessary is not a reasonable treatment, as most antibiotics are toxic to the patient as well. Further the use of inappropriate antibiotics or doses can encourage the development of drug resistance in the infectious organisms.
The biosensor described above overcomes these problems by determining the concentration of one or more species of bacteria present in the patient. Samples would be taken at intervals and tested for the bacteria's concentration. The change in the bacterial concentration over time would reflect the efficacy of the antibiotic treatment against the infectious organism or organisms. This ensures that an adequate amount of an appropriate antibiotic would be provided to the patient without providing excessive amounts of the antibiotic. The method described above may be used in a variety of situations to monitor response of organisms such as bacteria or fungi to drugs.
EXAMPLES
Example 1
Preparation of Fused silica Optical Fibers Derivatized with Long Chain Aliphatic Spacer Molecules Terminated with a 5′-0 -dimethoxytrityl-2′-deoxythymidine Nucleoside
Plastic-clad silica optical fibers with a diameter of 400 μm were purchased from 3M Specialty Optical Fiber (North York, ON, Canada). The cladding on the fibers was mechanically removed, and the fibers were cut to lengths of about 1 cm. One face on each fiber was polished by suspending the fiber over (and placing the end face of the fiber in contact with) the rotating plate of a Thermolyne type 37600 speed controlled mixer (Sybron Corporation, Dubuque, Iowa, USA) onto which 1200 grade emery paper was immobilized. All fused silica optical fibers were cleaned using a Harrick PDG-32G plasma cleaner (Harrick Scientific Corporation, Ossining, N.Y., USA) before activation with aminopropyltriethoxy silane (APTES).
The fibers were then washed with a 1:1 acetone/methanol mixture and stored in a vacuum desiccator The optical fibers were plasma cleaned for 5 minutes at low power (40 W) and were placed in a solution of 1:200 (v/v) aminopropyltriethoxy silane (APTES) in dry toluene This was done under a nitrogen atmosphere using glassware which was oven dried and previously treated with octadecyltrichlorosilane. The structure of the APTES coatings on fused silica substrates has previously been investigated by Vandenberg et al. (1991, J. Colloid and Interface Sci., 147: 103). The method of Arnold and co-workers (1989, Collect. Czech. Chem. Commun., 54: 523) was used to synthesize an aliphatic spacer arm terminated with 5′-O-dimethoxytrityl-2′-deoxythymidine. In this method 1,10-decanediol was condensed with succinic anhydride to form 1,10 decanediol bis-succinate, as illustrated in FIG. 1 ( a ). The bis-succinate was reacted with N-hydroxysuccinimide and 5′-O-dimethoxytrityl-2′deoxythimidine in the presence of N,N′-dicyclohexyl-carbodiimide (DCC) and 4-dimethylaminopyridine (DMAP) to yield a nucleoside functionalized spacer molecule. The spacer was then attached to the surface of the APTES treated optical fiber via amide formation.
Example 2
Preparation of Fused silica Optical Fibers Derivatized with Glycidoxypropyltrimethoxysilane Extended with Mono-Dimethoxytritylated Hexaethylene Glycol Substrate Linker Molecules
In order to grow oligonucleotides onto the surface of silica substrates (such as fused silica) by automated solid phase synthesis, the surface is functionalized with spacer molecules of at least 25 Å in length which had either an amine or a hydroxyl functionality at the terminus of the spacer molecule. A chemically resistant, non-hydrolyzable spacer molecule is employed. The method used was a modification of that reported by U. Maskos and E. M. Southern supra wherein the silica surface was treated with glycidoxypropyltrimethoxysilane (GOPS), followed by extension via treatment with hexaethylene glycol (HEG) under acidic conditions. For the purpose of creating biosensors with higher sensitivity and lower detection limits, this method is advantageous over the use of hydrocarbon tethers. The water soluble HEG linker will provide a more fluid environment (which should not self-assemble) so as to improve the ability of the immobilized DNA strands to hybridize with complementary material in solution (in terms of energetics and kinetics). The hydrophilicity of the linker will also facilitate the removal of adsorbed contaminants (e.g. proteins, organics) which may occlude the surface and contribute to drift in the fluorescence intensity. However, as HEG is bifunctional, there exists the possibility of creating non-reactive closed-loop structures which may significantly decrease the loading of oligonucleotides on the surface of the fibers. In order to eliminate this problem, one terminus of the HEG is protected with a dimethoxytrityl functionality prior to extension with GOPS. This strategy permits facile determination of the amount of support linkers bound to the silica surface. Removal of the trityl protecting groups by treatment with acid yields the highly colored trityl cation, which can be quantitatively measured by monitoring A (504 nm) of the deprotection solution. Knowing there is one trityl group released per linker molecule attached to the surface, the loading of HEG can easily be determined. Immobilization of a protected linker molecule provides the additional advantage that the hydroxyl groups produced after the attachment of the HEG to the epoxide moiety and all other surface silanols can be capped to prevent unwanted oligonucleotide growth at these sites. The presence of side product oligonucleotides, which are prematurely terminated due to the lack of a suitable support molecule, may decrease the sensitivity and selectivity of the sensor. The additional charge imparted from the anionic backbone of a side product strand may inhibit hybridization between the analyte strands and neighboring probe sequences. See: R. T. Pon Methods in Molecular Biology , Vol.20: Protocols for Oligonucleotides and Analogs, S. Agrawa, Ed, 1993, Humana Press, Inc. Totowa N.J. In conjunction with the use of non-hydrolyzable spacer molecules, t-butylphenoxyacetyl protected phosphoramidite synthons were employed. This labile protecting group can be quickly removed (15 min @ 55° C. or 120 min. at room temperature as compared to 12-16 hours @ 55° C. using 27% aqueous ammonia) thereby reducing the possibility of cleavage of the immobilized sequences by hydrolysis of the silyl ether bonds which ultimately anchor the strands to the fiber surface.
i) Gleaninq of Silica Substrates Prior to Functionalization with GOPS:
The buffer coating was mechanically stripped from the pre-cut optical fiber pieces (400 μm diameter×44 mm) and the cladding was dissolved by treatment with acetone. The fused silica substrates, i.e., optical fibers or wafers, were added to a 1:1:5 (v/v) solution of 30% ammonium hydroxide/30% hydrogen peroxide/water and the mixture was stirred at 80° C. for five minutes. The substrates were then removed and treated with a solution of 1:1:5 (v/v) conc. HCl/30% hydrogen peroxide/water and the mixture stirred at 80° C. for five minutes. The substrates were then sequentially washed with methanol, chloroform and diethyl ether, respectively, and dried in-vacuo.
ii) Synthesis and Purification of mono-dimethoxytritylated hexaethylene glycol (DMT-HEG):
Dimethoxytrityl chloride (7.1 g) was dissolved in 10 ml of dry pyridine and added dropwise to a stirred solution of hexaethylene glycol (5.65 ml) in 5 ml of dry pyridine under an argon atmosphere. Stirring was continued for 16 hours after which time the reaction mixture was combined with 50 ml of dichloromethane. The dichloromethane solution mixture was twice shaken with 900 ml portions of 5% aqueous sodium bicarbonate and then with three 900 ml portions of water in order to remove unreacted HEG, pyridine, and pyridinium salts. The product was purified by liquid chromatography using silica gel and a solvent system of 0.1% triethylamine in 1:1 dichloromethane/diethyl ether. The identity of the product was confirmed by proton NMR spectroscopy (200 MHz).
iii) Functionalization of Fused Silica Substrates with 3-Glycidoxypropyltrimethoxysilane (GOPS):
The cleaned fused silica substrates were suspended in a stirred solution composed of 40 ml xylene, 12 ml GOPS, and a trace of Hünig's base at 80° C. overnight. The fibers were then sequentially washed with methanol, chloroform, ether, and then dried in-vacuo.
iv) Linkage of DMT-HEG to GOPS Functionalized Silica Substrates:
The GOPS functionalized fibers were suspended in a stirred solution of 1:4:8 (v/v) DMT-HEG/diethyl ether/toluene containing a catalytic amount of sodium hydride under an argon atmosphere. The reaction mixture was stirred for 14 days after which time the fibers were removed and washed sequentially with methanol, chloroform, ether, and then dried in vacuo.
v) Capping of Unreacted Silanol and Hydroxyl Functionalities with Chlorotrimethyl-silane:
The fused silica fibers functionalized with DMT-HEG were suspended in a solution of 1:10 (v/v) chlorotrimethylsilane/pyridine for 16 hours under an argon atmosphere at room temperature.
Example 3
Preparation of Fused Silica Optical Fibers Derivatized with Mono-Dimethoxytritylated Hexaethylene Glycol Substrate Linker Molecules via Mesylate Activation
The details of the preparation of the fused silica substrates and DMT-HEG synthesis are provided in example 2(i and ii). DMT-HEG (0.5 g) was suspended in 50 ml anhydrous pyridine. The solution was maintained under an anhydrous argon atmosphere and stirred. while 1.2 equivalents of methanesulfonyl chloride was added dropwise. The reaction allowed to proceed for 60 minutes at room temperature with stirring. The cleaned fused silica and silicon substrates were introduced into the solution containing the mesylated DMT-HEG and the substrate functionalization reaction allowed to proceed for 4 days with stirring at 40° C. under an argon atmosphere. Following the 4 day incubation period, the solution was decanted away from the functionalized substrates which were then washed with copious amounts of dichloromethane. Washings were continued until no discernible absorbance at 504 nm was observed from the wash solution made acidic by treatment with trichloroacetic acid. The functionalized substrates were then capped as per the methods of example 2(v) and stored in-vacuo and over P 2 O 5 until needed.
Example 4
Preparation of Fused silica Optical Fibers Derivatized with Mono-Dimethoxytritylated Hexaethylene Glycol Phosphoramidite Substrate Linker Molecules via Standard β-Cyanoethylphosphoramidite Coupling on an Automated Synthesizer
The details for the preparation of the fused silica substrates and DMT-HEG are provided in example 2(i) and 2(ii), respectively. DMT-HEG (0.5 g) was suspended in a solution consisting of 12 ml of anhydrous THF and 4 ml of anhydrous N,N-diisopropyl ethylamine. The solution was maintained under an anhydrous argon atmosphere and stirred at all times. 1.1 equivalents of 2-cyanoethyl-N,N-diisoproylamino-phosphochloridite was added dropwise to the DMT-HEG solution and the reaction allowed to proceed for 90 minutes at room temperature. TLC analysis (1:1 CH 2 Cl 2 /diethyl ether) indicated quantitative formation of the DMT-HEG phosphoramidite synthon (R f =0.7). The reaction product was thrice extracted into ethyl acetate from a 5% sodium bicarbonate solution. The organic phase was separated from the aqueous layer, dried over NaSO 4 , filtered and the solvent removed under reduced pressure. The product was then stored dry and at −20° C. under an anhydrous argon atmosphere until required. Functionalization of fused silica substrates was then done as part of a standard coupling cycle using the automated solid phase DNA synthesizer and a 0.1 M solution of the DMT-HEG phosphoramidite in anhydrous THF. The methods for automated oligonucleotide synthesis are detailed in example 5. The capping procedure detailed in example 2(v) was then done in order to block any undesired reactive sites on the substrates.
Example 5
Synthesis of Oligonucleotides onto Substrate Linker Functionalized Fused Silica Waveguides
All DNA synthesis was done by the well established β-cyanoethylphosphoramidite method with an either an Applied Biosystems 381A or 391 EP DNA Synthesizer using susbtrate linker functionalized controlled-pore glass beads, fused silica optical fibers, planar fused silica wafers, or planar silicon wafers. Automated solid-phase DNA synthesis is well known and is described in detail elsewhere (Beaucage et al., 1992, Tetrahedron Letters, 48: 2223-2311 ; Oligonucleotides and Analogues; A Practical Approach , F. Eckstein, Ed. Oxford University Press, NY, 1991). The substrate linker functionalized optical fibers were placed into an emptied Applied Biosystems (ABI) Oligonucleotide Purification Cartridge column (OPC-column) or 10 μmol scale synthesis column with the dead volume being taken up by inert polyethylene pieces. The end filter papers were replaced (ABI) and the column ends were crimped closed using aluminum seals. Synthesis of oligomers onto the optical fibers was carried out at the 0.2 μmol. scale with a pulsed-delivery cycle in the “trityl off” mode. The β-cyanoethylphosphoramidite cycle was used as supplied by ABI with the exception of extended nucleoside coupling times (2-10 min.) and increased solution delivery times to accommodate the larger synthesis columns. With the exception of thymidine synthons, t-Butylphenoxyacetyl protected phosphoramidite synthons were used in conjunction with a t-butylphenoxyacetic anhydride capping solution as supplied by Millipore Inc.
In the case where polythymidilic acid oligonucleotides were grown on the optical fibers, deprotection of the phosphate blocking groups from the immobilized oligomer was achieved by standing the fibers in a solution of 2:3 triethylaminelacetonitrile at room temperature for 1.5 hours. This procedure caused the loss of the phosphate blocking group via β-elimination while not cleaving the singlestranded DNA (ssDNA) from the optical fibers. In the case where oligonucleotides containing bases other than thymine were grown, the following protocol was used for phosphate and nucleobase deprotection. A 30% ammonium hydroxide solution was drawn up into the synthesis column containing the optical fibers functionalized with immobilized oligonucleotides using a syringe and a male-to-male luer adapter. The fibers submerged in ammonia were allowed to stand for two hours at room temperature after which time the ammonia solution was expelled from the column and the contents of the column were washed five times with 5 ml portions of sterile water. The deprotection solutions and washings were collected and concentrated to a total volume of 1 ml. A 260 nm of the concentrated deprotection solution was measured in order to determine the quantity of DNA liberated from the fused silica substrates. Based on the results of the trityl cation assay and A 260nm of the deprotection solution, it was found that ˜20% of the oligomers remained attached to the surface following the ammonia deprotection procedure. In the case where oligonucleotides of mixed base sequence were grown onto optical fibers, the oligonucleotide sequence was (5′-TAG GTG AGA CAT ATC ACA GA-3′SEQ ID NO: 1), which is a nucleic acid probe for the E03 forward sequence of the Candida albicans genome.
Fibers coated in ssDNA were either stored dry or kept in a solution of 1:1 ethanol/water. All fibers were cleaned prior to use by sonication in a solution of 1:1 ethanol/water for 5 minutes in order to remove any fluorescent contaminants adsorbed to the surface of the fibers.
Example 6
Biosensor Characterization by Trityl Cation Assay
All oligonucleotide syntheses were evaluated by spectroscopic quantitation of trityl cation released during the trichloroacetic acid treatment steps of the automated synthesis. The collected fractions of trityl cation were diluted with 2.0 ml of 5% TCA in 1,2-dichloroethane immediately prior to making absorbance measurements. Absorption at 504 nm was measured in order to determine the concentration and the total number of trityl cation moieties released during each TCA deprotection step of the synthesis. In this way, the total number of oligomers successfully grown onto the solid supports was determined.
As there exists no discernible decrease in the amount of trityl cation released during successive deprotection steps, it may be safely assumed that the coupling efficiency of 99.5% or better suggested by the manufacturer of the automated synthesizer (ABI) was achieved. The results of a trityl cation assay for a synthesis of dT 20 onto optical fibers by the methods given in Examples 1 and 5 are shown in FIG. 8 .
Example 7
Generation of Complementary and Non-complementary Nucleic Acids
Synthesis of dA 20 and rA 20 was done using a conventional LCAA-CPG support with the β-cyanoethylphosphoramidite cycle supplied by ABI. A nonadecamer of random base composition (dR 19 ) was also prepared by simultaneously introducing all four phosphoramidite reagents to the column at each coupling step. Standard deprotection with aqueous ammonia (29%, 1.5 ml, 24 h) was used to liberate the oligomers from the solid support and remove the base protecting groups. For the case of the rA 20 , deprotection of the phosphate blocking groups, base protecting groups and cleavage from the CPG support was done by treating the oligomers with 1.5 ml of a solution consisting of 4 parts aqueous ammonia and 1 part ethanol for 48 hours at room temperature. The aqueous solution containing the. oligonucleotides was then collected, evaporated to dryness, and the residue treated with 300 μl of an anhydrous solution of 1 M tetra-N-butyl ammonium fluoride in THF overnight at room temperature. After the incubation time, the reaction was quenched by adding 1 ml of water to the reaction mixture. Crude oligomer was purified by polyacrylamide gel electrophoresis and reverse phase liquid chromatography or size exclusion chromatography.
Example 8
Detection and Quantification of Complement DNA (cDNA), Complement RNA (cRNA) and Non-complement Nucleic Acid by the Optical Sensor Fabricated by the Procedures of Examples 1 and 5
An optical fiber functionalized with polythymidilic acid icosanucleotide was selected at random from the batch of fibers (ca. 25) created in example 1 and was positioned under the objective of the microscope, as illustrated in FIG. 4 ( a ). In this orientation the incident laser radiation entered the proximal terminus and was totally internally reflected throughout the fiber. The majority of the fiber was submerged in a hybridization buffer solution consisting of 1.0 M NaCl and 50 mM sodium phosphate (pH 7.4) in sterile water contained within a 4 ml plastic cuvette. Hybridization buffer was passed through an acrodisc® filter immediately prior to introduction to the cuvette. Emitted fluorescent radiation, from the stimulated fluorescent molecules associated with the double-stranded nucleic acids, was directed back towards the microscope by total internal reflection. The emission from the fluorescent molecules was separated from the excitation radiation by a dichroic mirror and directed to a photomultiplier tube. The photomultiplier tube provided measurements of the intensity of fluorescence emission. Fluorescence intensity values are reported with the system at 25° C. to avoid inconsistencies cause by the temperature dependence on fluorescence quantum efficiency and as relative quantities, thereby obviating the need to control experimental parameters such as laser intensity, optical alignment and photomultiplier tube (PMT) gain which are beyond accurate control from day to day.
In order to affect hybridization with the immobilized nucleic acid strands, dA 20 ssDNA was added to the plastic cuvette containing the suspended fiber in fresh hybridization buffer at a temperature of 85° C. This temperature was chosen as it is sufficiently greater than the 60° C. duplex melting temperature (T m , the temperature at which half of all the duplexes present are dissociated) and is well below the boiling point of the buffer. Incubation at temperatures below T m has been shown to cause incomplete hybridization wherein only a fraction of the bases on each strand interact to form partially hybridized complexes (Rubin et al, 1989, Nucleic Acid and Monoclonal Antibody Probes, B. Swaminathan and G. Prakash, Eds., Marcel Dekker, Inc., NY, pp. 185-219). Though covalent immobilization of ssDNA removes one degree of freedom from the oligomer, hybridization at temperatures initially above the duplex T m ensures the formation of duplexes with the greatest possible extent of overlap. In all cases, no appreciable intensity change from that of the baseline was observed after the 90 minute incubation period. The solution was allowed to stand and cool to room temperature (25° C.) between 30 and 90 minutes after which the fiber was flushed with 60 ml of hybridization buffer (25° C.) to remove the excess strands.
Intercalation of the fluorophore into the dsDNA was achieved by injecting 10 μl of a 1 mg·ml −1 aqueous solution of ethidium bromide (EB) into the cuvette and allowing the solution to stand for 15 minutes followed by washing the fiber by flushing the cuvette with 60 ml of fresh hybridization buffer (25° C.).
The response of the fiber optic DNA biosensor to EB and cDNA is shown in FIG. 9 . As a control experiment, 10 μL of a 1 mg·ml −1 aqueous solution of EB was added to the cuvette in which the fiber functionalized with ssDNA was suspended. After 15 minutes, 60 ml of fresh hybridization buffer (25° C.) was flushed through the cuvette in order to remove any non-specifically bound ethidium cation and no discernible increase in fluorescence intensity from the fiber was observed. A 104±15% increase in the fluorescence intensity was observed from the fiber which was exposed to 189 ng·ml −1 of cDNA and stained with EB relative to the baseline value for the cleaned sensor with only ssDNA on the waveguide surface. The fiber was regenerated by flushing the cuvette and optical sensor 30 ml of hot (85° C.) buffer solution over a period of c.a. 30 seconds and the system allowed to stand for five minutes. After the five minute wait, an additional 30 ml of hot buffer was flushed through the cuvette to wash away the dissociated cDNA strands. This procedure is known to melt DNA duplexes as the buffer temperature was well above the T m of the dsDNA. The fluorescence intensity returned, within experimental uncertainty, to the initial intensity observed at the beginning of the experiment. The same hybridization experiment was repeated where the optical sensor was exposed to 757 ng·ml −1 of cDNA during the hybridization procedure. This yielded an increase of 720±20% in the observed fluorescence intensity from the sensor with respect to the baseline value. In contrast, a similar concentration of non-complementary sequences (a nonadecamer of random base sequence) gave essentially no response, as shown in FIG. 9 ( a ).
A 3.8 ng·μl −1 solution of rA 20 (450 μl) was introduced into a cuvette containing hot hybridization buffer and the sensor to provide a 570 ng ml −1 solution of cRNA. The same hybridization and staining procedure as used for cDNA was followed. The response profile for this hybridization procedure is shown in FIG. 9 ( b ). A comparison of response of the biosensor with immobilized dT 20 to cDNA and cRNA agree to within experimental error.
Example 9
Effective of Ethidium Bromide (EB) Staining Time and Concentration
The staining time of the sensor with EB, was changed after each hybridization with cDNA. For each determination, injections of 30 μl of 56.8 μg·ml −1 solution of aqueous dA 20 were made and the hot hybridization buffer in the cuvette, which contained the cDNA strands, was allowed to cool to room temperature over a time of 30 minutes. A 1 mg·ml −1 solution of EB in water (10 μl) was added to the cuvette after each hybridization to provide an EB concentration of 8.4-10 −3 M. A staining time of 20 min. with 8.4×10 −3 M EB was required to generate ≧99% of the full signal, as shown in FIG. 10 ( a ).
To study the effect of EB concentration during dsDNA staining, all hybridization parameters were the same as those used to study staining time and a staining time of 20 min. was used. Staining with EB solutions of concentrations of 8.5×10 −3 M or greater were required to generate ≧99% of the full staining in 20 min., as shown in FIG. 10 ( b ).
Example 10
Long Term and Thermal Stability of the Nucleic Acid Sensor
The robustness of the optical sensors, and DNA as a biorecognition element, was made evident by the maintenance of activity after long term storage and vigorous cleaning conditions. Fibers that were stored for over 1 year in vacuo, in 1:1 ethanol/water solutions, absolute ethanol, or dry at −20° C. provided identical response characteristics to freshly prepared fibers. Adsorbed fluorescent contaminants which were accumulated through long term storage were completely removed (as confirmed through fluorescence microscopy) by sonicating the fibers in a solution of 1:1 ethanol/water with full maintenance of activity and sensitivity. FIG. 11 ( a ) shows the response of a 1 month old fiber (stored in vacuo) used with no cleaning of the surface and (b) an 11 month old fiber (stored dry at −20° C.) which had been cleaned by sonication in ethanol solution. It should be noted that the sensitivity of the cleaned 11 month old fiber is identical to that of 1 month old fibers cleaned by the same procedure (data not shown). Cleaning of the sensor by sonication prior to use has consistently been observed to increase the sensitivity of the device by a factor of c.a. 2.5. The sensors have provided femtomolar detection limits and a response which is linear with the concentration of cDNA (M.W.=6199 g·mol −1 ). The regression lines shown in FIG. 11 show good fits to the data points with r 2 values of 0.965 and 0.968 for the 1 month and 11 month-old fibers, respectively. From this data, the sensitivity of the optical sensor (11 month-old, fabricated by the protocols of examples 1 and 5) was determined to be an increase in fluorescence intensity of 203% per 100 ng·ml −1 of cDNA with a measured limit of detection of 86 ng·ml −1 . Maintenance of calibration has been observed for all experiments done thus far in which as many as 5 regenerations have been done over durations of up to 12 hours.
The ability to clean and sterilize a bioprobe or biosensor device so that it may be usable in an on-line configuration is a significant advantage. As the specific binding properties of nucleic acids are based on secondary structure, the use of nucleic acids in biosensor fabrication leads to devices which are not only stable to prolonged storage, but also to harsh washing conditions and sterilization. A summary of the effects of cleaning by sonication in absolute ethanol (15 minutes) and autoclaving (120° C. for 20 minutes at 4 atmospheres pressure in sterile water) on the response of the sensors to (˜400 ng·mL −1 ) is shown in the Table which follows. Both sonication in ethanol and autoclaving are observed to improve the response of the sensor, most likely through the removal of contaminants on the surface of the sensor (stored dry for 11 months, or stored in ethanol).
TABLE 1
Effect of storage conditions, cleaning, and sterilization on sensor
response to
400 ng · ml −1 cDNA.
Cleaning/
Sterilization
Relative Fluorescence
Storage Conditions
Conditions
Intensity Increase (%)
1:1 Ethanol/Water (25° C.)
—
333 ± 20
95% Ethanol (25° C.)
—
395 ± 20
Dry (−20° C.)
—
341 ± 20
1:1 Ethanol/Water (25° C.)
Autoclave
430 ± 20
1:1 Ethanol/Water (25° C.)
Sonication
453 ± 20
Example 11
Thermal Denaturation Studies of the cDNA: Immobilized DNA Complex on the Sensors Created from the Protocols of Examples 1 and 5 and Comparison to that of the Same Oligonucleotide Complex in Solution
i) Thermal Denaturation Investigations of Aqueous dT 20 with Aqueous dA 20 .
Equimolar amounts of each oligomer in hybridization buffer (1 M NaCl, 10 mM PO 4 , pH=7.0) were mixed so that the final concentration was approximately 1 μM in each strand. Prior to thermal melt studies the oligonucleotide mixture was heated briefly to 80° C. and slowly cooled to 20° C. in order to hybridize all of the strands. The samples were held at the low temperature limit for 15 minutes prior to initiating melt studies, to allow for thermal equilibration. The temperature was then ramped at 0.5° C. intervals at a rate of 0.5° C./min. while the absorbance was recorded at 260 nm.
ii) Melt-Curve Investigations of Immobilized dT 20 with cDNA.
Sequences of dT 20 were immobilized onto planar fused silica wafers (5 mm ×10 mm×1 mm) according to the protocols in examples 1 and 5. The immobilized dT 20 was hybridized with complementary dA 20 sequences by immersing the wafer in a 56.8 ng·ml −1 solution of dA 20 at 85° C. and allowing the immersed wafer to cool to room temperature (25° C.). The wafer was then removed from the cDNA solution and washed with room temperature hybridization buffer solution. The wafer was then suspended in a quartz cuvette that was placed in the temperature controlled cuvette housing of the UV-vis spectrometer. The placement of the wafer was adjusted so that it rested in the path of the light beam. The dead volume beneath the wafer was taken up by inert packing material. Absorption spectra were collected at approximately 2° C. increments of temperature in the range from 29° C. to 76° C. The temperature in the cuvette was set by programming an external circulating bath to a specific temperature and the temperature of the buffer solution surrounding the fused silica wafer was quantitatively measured using a silanized glass encapsulated thermistor. Measurements of absorption at each temperature were done by integrating 100 spectra in the wavelength range between 220 nm and 320 nm.
iii) Hypochromicity and Melt-Curve Thermodynamics.
The transition between an ordered duplex state and the disordered denatured state for systems of complementary nucleotides can be monitored and analyzed by UV-Visible absorbance spectroscopy to determine the duplex melting temperature (T m ). The extent of hybridization (i.e. the number of base pairs formed per duplex) was determined by a comparison of melt profiles for the immobilized oligonucleotides to similar reported values and dA 20 +dT 20 in solution.
The fraction of single strands present in the system at any temperature (f ss (T)) may be determined through the use of the following equation: f ss ( T ) = A ( T ) - A ds ( T ) A ss ( T ) - A ds ( T )
where A(T), A ss (T), and A ds (T) are the absorbances of the experimentally obtained melting curve, the upper baseline (single stranded oligomers), and the lower baseline (double stranded oligomers) respectively at temperature T (Nelson, J. W.; Martin, F. H.; Tinoco Jr., I. Biopolymers 1981, 20, 2509-2531.). By plotting f ss against temperature, the duplex melting temperature can be obtained by determining the temperature at which f ss =0.5.
iv) Melt-Curve Studies of Support Bound Duplex DNA and Aqueous Phase DNA.
The purpose of the thermal denaturation studies was to examine whether linkage of an oligonucleotide to a solid support through a terminal nucleotide phosphate would cause the loss of degrees of freedom with respect to the availability of each nucleotide to partake in formation of the double stranded structure. Melt profiles for the thermal denaturation of dsDNA immobilized on the surface of a fused silica wafer and dsDNA in solution were obtained, and the results of these investigations are summarized in FIG. 12 . The duplex melting temperature of the immobilized strands with aqueous phase complement strands was 62.4±0.3° C. The T m value for the aqueous phase dA 20 +dT 20 duplex was determined to be 60.5° C. using the software supplied by Varian. Kibler-Herzog et. al. (Kibler-Herzog, L.; Zon, G.; Whittier, G.; Mizan, S.; Wilson, W. D. Anti - Cancer Drug Design 1993, 6, 65-79.) have reported the melting temperature of a dA 19 +dT 19 duplex in 1.02 M NaCl to be 61.1 ° C. This suggests that for the immobilized oligomers investigated in this work, the extent of hybridization was complete with base pairing of 20 bases per strand. The small differences in the three T m values may be accounted for by the fact that each of these experiments was done on a different instrument at different times, and the salt concentration used in this work was slightly lower than that used by Kibler-Herzog et al. As the duplex stability in low ionic strength buffers is less than that in high ionic strength buffers, it would be expected that the melting temperature of the immobilized dT 20 +dA 20 . duplex would be higher in the buffer of lower stringency (Puglisi, J. D.; Tinoco Jr., I.; Methods in Enzymology , 1989, 180, 304-325.). In addition to this, a greater value of T m for the immobilized duplex over the aqueous phase duplexes should not be considered unusual as only one of the strands will experience a significant gain in entropy upon melting of the immobilized duplex. These factors lead to the conclusion that, within experimental uncertainty, the immobilized dT 20 +dA 20 duplexes were more stable, if not as stable, as the aqueous phase dA 20 +dT 20 and dA 19 +dT 19 duplexes. This also suggests that no hindrance of duplex formation is observed with respect to the availability of the bases for hybridization. This result is in accord with the investigations of Wolf et al. (Wolf, S. F.; Haines, L.; Fisch, J.; Kremsky, J. N.; Dougherty, J. P.; Jacobs, K. Nucleic Acids Research 1987, 15, 2911-2926.), in which oligonucleotides bound to solid supports via a long chain aliphatic tether at the strand termini (3′-end) were not observed to be hindered with respect to hybridization efficiency
Example 12
Detection of cDNA with and Optical Sensor functionalized with an Oligonucleotide Probe Sequence for Candida albicans
Optical Sensors were created by the protocols in examples 2 and 5 where the oligonucleotide sequence (5′-TAG GTG AGA CAT ATC ACA GA-3′SEQ ID NO: 1), which is a nucleic acid probe for the E03 forward sequence of the Candida albicans genome, was assembled onto the substrate linker functionalized fibers. Hybridization and staining protocols as reported in example 9 were followed. The response of the sensor to cDNA (20 nucleotides in length) is shown in FIG. 13 . Linear calibration (r 2 =0.988), good sensitivity (100% fluorescence intensity increase per 89 pM increase in concentration in the 4 ml of solution surrounding the optical sensor) and low detection limits (6×10 10 molecules) were observed for the device.
Example 13
Fabrication of Optical Sensors with Immobilized Polythymidilic Acid Icosanucleotides Functionalized at the 5′-terminus with N5-Tethered 3,8-Diamino-6-phenylphenanthridium Cation
i) Synthesis of Methyl-(12-hydroxy)dodecanoate.
12-hydroxydodecanoic acid (5 g) was dissolved in 100 ml of dry methanol to which was added a solution of p-toluenesulfonic acid (88 mg) in 5 ml of methanol drop-wise over a 15 minute time-span. The solution was refluxed for 16 hours after which time the solvent was removed under reduced pressure. The product was then twice extracted into chloroform from a 5% aqueous solution of sodium bicarbonate. The organic phase was recovered, dried over NaSO 4 , and the solvent removed under reduced pressure.
ii) Tosylation of Methyl-(12-hydroxy)dodecanoate
Methyl-(12-hydroxy)dodecanoate (1.6 g, 7 mmol) was placed in and oven dried flask cooled under anhydrous argon and treated with 3 ml of a solution of p-toluenesulfonyl chloride (1 eq., 7 mmol, 1.31 g) in dry pyridine. The solution was stirred at 25° C. under an inert atmosphere for 16 hours. The solvent was then removed under reduced pressure and the tosylated product was stored dry at −20° C. until needed.
iii) N-Alkylation of 3,6-dinitro-6-phenyl-phenanthridine with the Tosylate of Methyl-(12-hydroxy)dodecanoate.
3,8-Dinitro-6-phenyl-phenanthridine (3.5 mmol, 1.2 g) was combined with the tosylated methyl-(12-hydroxy)dodecanoate (7 mmol, 2.7 g) in dry nitrobenzene and the solution stirred for 6 hours at 160° C. under an argon atmosphere. The alkylated quaternary ammonium salt was precipitated from the mother liquor by addition of diethyl ether and collected by filtration. The product was further purified by silica gel column chromatography (25% methanol in chloroform) and recovered as a dark purple solid.
iv) Reduction of 3,8-dinitro-5-methyldodecanoate-6-phenyl-phenanthridium Chloride
3,8-Dinitro-5-methyldodecanoate-6-phenyl-phenanthridium chloride (1.3 mmol, 0.72 g) was dissolved in 10 ml of THF and stirred over NiCl 2 .6H 2 O (10.68 g) and powdered Al (0.81 g). Water (0.3 ml) was then added to initiate the formation of the black Ni/Al catalyst and the reaction allowed to proceed for 15 minutes. The solution containing the reduced product was recovered by filtration, followed by removal of the solvent under reduced pressure. The product was purified by silica gel column chromatography (25% methanol in chloroform) and recovered as a dark purple solid (4%, 0.03 g).
v) Tritylation of 3,8-diamino-5-methyldodecanoate-6-phenyl-phenanthridium Chloride
3,8-diamino-5-methyidodecanoate-6-phenyl-phenanthridium Chloride (0.03 g, 62 μmol) was dissolved in dry pyridine and treated with dimethoxytrityl chloride (3 eq, 68 mg) suspended in dry pyridine (4 ml). The reaction was allowed to proceed for 16 hours at 25° C. with stirring under an inert atmosphere. The solvent was then removed under resuced pressure and the product purified (58%, 36 μmol) by reverse phase HPLC (isocratic elution with 1:1 methanol/water).
vi) Deprotection of the methyl-ester protecting group on 3,8-Bis(dimethoxytritylamino)-5-methyldodecanoate-6-phenyl-phenanthridium Chloride
3,8-Bis(dimethoxytritylamino)-5-methyldodecanoate-6-phenyl-phenanthridium chloride (36 μmol) was suspended in 80 ml of a solution of 1:3 water/methanol. The solution was degassed and treated with KOH (4 eq., 160 μmol) for 16 hours with stirring at 25° C. The reaction was quenched and the pH neutralized by treatment with HCl (1 eq, 15 μl of conc.).
vii) Synthesis of 5′-aminohexyl-dT 20 Functionalized Optical Sensors.
DMT-HEG-GOPS functionalized optical fibers (prepared according to the method of Examples 2) were functionalized with polythymidilic acid icosanucleotide (according to the method of example 5) terminated an N-trifluoroacetamide protected aminohexyl moiety at the 5′-end by use of the commercially available Aminolink 2® phosphoramidite synthon from ABI. Deprotection of the phosphate blocking groups from the immobilized oligomers was achieved by standing the fibers in a solution of 2:3 (v/v) triethylamine/acetonitrile at room temperature for 1.5 hours. Removal of the trifluoroacetamide protecting group on the aminohexyl functionality located at the 5′-end of the immobilized strands was done by exposing the fibers to a 10 −3 M solution of sodium borohydride in absolute ethanol for 1 hour at room temperature. The fibers were then washed once in a solution of 10 −1 M HCl followed by washing with copious amounts of sterile water.
viii) Attachment of the Trityl-Protected Tethered Ethidium Analogue to the Aminohexyl Functionalized Optical Fibers:
The fully deprotected fused silica optical fibers functionalized with 5′-aminohexyl polythymidilic acid icosanucleotides were immersed in a solution containing 5 mg of the DMT-protected tethered ethidium analogue, 40 μl of 1-methylimidazole, and 1.91 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide in 50 ml of water. After a 7 day incubation period at room temperature, the fibers were washed five times each with 50 ml portions of water, ethanol, and dichloromethane, respectively. The proportion dye-functionalized oligonucleotides was determined by measurement of the amount of dimethoxytrityl released from each detritylation step during automated synthesis and that from the deprotection procedure used to restore the primary amine moieties on the dye. From these assays it was determined that 63% of the immobilized oligonucleotides were functionalized with tethered dye.
ix) Characterization of the Fluorescence Response of the Reagentless Sensors with Tethered Fluorophore:
The response of the reagentless sensor to 720 ng of complement DNA is shown in FIG. 14 . Hybridization was done at 40° C. in a buffer consisting of 1 M NaCl and 50 mM phosphate (pH 7.0). It should be noted that this sensor has a significantly improved response time over the sensors without tethered dye. 99% of the full analytical signal was reached in c.a. 6 minutes after injection of the complementary strands for the reagentless system while 45 minutes was required for full signal generation by the sensors without tethered dye (see FIG. 10 { a }).
Example 14
Detection of TAT Triple-Helical DNA Using a Fiber Optic Biosensor
i) Background
One important avenue not yet explored by the fiber-optic nucleic acid biosensor community is the investigation of triple-stranded oligonucleotide formation. Typically, a number of spectroscopic techniques (CD, NMR, UV and fluorescence spectroscopy) in addition to gel mobility shift assays need to be implemented in order to study the formation of triple-helical nucleic acids. However, each of these methods have problems in terms of either the amount of material that is required for analysis (NMR, CD, and gel mobility assays), or that they are limited to investigations of only certain triplex systems (e.g. only TAT triplexes can be monitored by UV absorption spectroscopy at 284 nm).
Various groups have developed methods for triplex detection ({i} Geselowitx, D. A.; Neumann, R. D. Bioconjugate Chem ., 1995, 6, 502. {ii} Bates, P. J., Dosanjh, H. S.; Kumar, S.; Jenkins, T. C.; Laughton, C. A.; Neidle, S. Nucleic Acids Res ., 1995, 23, 3627.). The use of nucleic acid binding ligands to identify DNA structures and morphology is one such method. Many ligands are known to interact in a noncovalent manner with the target oligonucleotide. Binding modes can be characterized as: (i) intercalation of the ligand, in which typically a planar aromatic moiety slides between the DNA bases—stabilized by π-π stacking and dipole interactions, or (ii) minor or major groove interaction which is stabilized by hydrogen bonding, hydrophobic and/or electrostatic interactions (Long, E. C.; Barton, J. K. Acc. Chem. Res . 1990, 23, 273.). Ethidium bromide binds to both duplexes and triplexes via an intercalative mode (Waring, M. J. Biochim. Biophys. Acta , 1966, 114, 234.), and this has been studied extensively by fluorescence methods. The fluorescence quantum efficiency of the ethidium cation increases when intercalated into duplexes (LePecq, J. B.; Paoletti, C. J. Mol. Biol ., 1967, 27, 87.) and triplexes (Mergny, J. L.; Collier, D.; Rougée, M.; Montenay-Garestier, T.; Hélèn, C. Nucleic Acids Research , 1991, 19, 1521. , Scaria, P. V.; Shafer, R. H. J. Biol. Chem , 1991, 266, 5417), however, it has been shown that there is a marked difference in the binding efficiency and hence fluorescence intensity between the two types of complexes. LePecq and Paoletti were the first to observe that the fluorescence enhancement of ethidium during interaction with the duplex (poly rA)·(poly rU) was significantly greater than for binding to the triplex (poly rA)·(poly rU) 2 (LePecq, J. B.; Paoletti, C. C. R. Acad. Sc. Paris 1965, 260, 7033). More recent studies have confirmed that the fluorescence intensity of intercalated ethidium bromide is greater for duplexes than triplexes of ribonucleic acid, and that a temperature dependence exists for deoxyribonucleic acids (Mergny, J. L.; Collier, D.; Rougée, M.; Montenay-Garestier, T.; Hélène, C. Nucleic Acids Res ., 1991, 19, 1521., Scaria, P. V.; Shafer, R. H. J. Biol. Chem ., 1991, 266, 5417., Fang, Y.; Bai, C. L.; Zhang, P. C.; Cao, E. H.; Tang, Y. Q. Science In China (Ser. B), 1994, 37, 1306.). The results of molecular modeling studies suggest that a reduced binding affinity of ethidium for triplexes (relative to duplexes) exists due to the energetic cost of destacking base triplets as compared to successive base pairs (Sun, J. S.; Lavery, R.; Chomilier, J.; Zakrzewska, K.; Montenay-Garestier, T.; Hélène, C. J. Biomol. Struct. Dynam ., 1991, 9, 425.). This is partially offset by the quantum efficiency of ethidium bromide in triplex DNA which is greater than that for duplex DNA. Short homopolymeric T*AT triplexes have been the subject of seminal fluorescence studies. Letsinger et al. (Salunkhe, M., Wu, T. & Letsinger, R. L. (1992) J. Am. Chem. Soc . 114, 8768-8772.) have shown that for parallel T*AT triplexes, the fluorescence intensity of ethidium cation decreases dramatically in comparison to fluorescence intensity of the ligand bound to AT duplexes. Independent confirmation of decreased fluorescence intensity for ethidium bound to parallel T*AT triplexes (2xdT 10 :dA 10 ) relative to duplexes (dT 10 :dA 10 ) has appeared (Fang, Y.; Bai, C. L.; Zhang, P. C.; Cao, E. H.; Tang, Y. Q. Science In China ( Ser. B ), 1994, 37,1306.).
We chose to investigate both parallel and antiparallel TAT triplexes as these sequences have been well documented in the literature (Plum, G. E.; Pilch, D. S.; Singleton, S. F.; Breslauer, K. J. Annu. Rev. Biophys. Biomol. Struct . 1995, 24, 319, and references therein). Branched nucleic acids as described by Damha et al. (Hudson, R. H. E.; Damha, M. J. Nucleic Acids Res. Symp. Ser . 1993, 29, 97., R. Hudson, A. Uddin, and M. Damha J. Am. Chem. Soc ., 1995, 117, 12470.) were used in this study as the unique architecture of bNAs has been utilized to stabilize reversed-Hoogsteen and Hoogsteen TAT triplexes. Investigations were also done to determine the best oligonucleotide orientation on the support for the detection of TAT triplexes. The motivation behind this research endeavor was then to create a rapid, reliable, reproducible assay for the detection of triple-helical nucleic acid formation. The development of a triple-helical assay, is an extension of work initiated for the detection of nucleic hybridization (Watson-Crick motif using fiber optic total internal reflection fluorecence (TIRF) sensors functionalized with single-stranded deoxyribonucleic acid (ssDNA) probes.
ii) Synthesis of Oligonucleotides on Optical Fibers.
Optical fibers were activated by protocols given in example 2 and polyadenilic decanucleotides were assembled onto the substrate linker molecules on the fiber surface as per the methods given in example 5. Two batches of fiber were created, the first using commercially available N 6 -phenoxyacetyl-5′-O-DMT-2′deoxyadenosine-3′-O-[(β-cyanoethyl) N, N-diisopropyl]phosphoramidite from Millipore Inc. to assemble decanucleotides with the 5′-terminus oriented away from the fiber surface. N 6 -phenoxyacetyl-3′-O-DMT-2′deoxyadenosine-5′-O-[(β-cyanoethyl)N,N-diisopropyl]phosphoramidite was prepared via standard protocols and used to grow oligonucleotide on the functionalized fibers in a reversed (fiber→substrate linker→5′-dA10-3′) orientation.
iii) Synthesis of Branched Oligonucleotides.
The “V” branched sequence 1 (FIG. 15) was synthesized on an Applied Biosystems 381A instrument using a 1 μmol scale synthesis cycle and β-cyanoethylphosphoramidite chemistry. Purification, desalting, and analysis of the branched oligonucleotide 1 by polyacrylamide gel electrophoresis was accomplished by our detailed protocols (Damha, M. J., Ganeshan, K., Hudson, R. H. E., Zabarylo, S. V., (1992) Nucleic Acids Res 20, 6565-6573; Damha, M. J.; Ogilvie, K. K. In Methods in Molecular Biology, Vol. 20 : Protocols for Oligonucleotides and Analogs ; Agrawal, S., Ed.; Humana Press, Inc.: Totowa, N.J., 1993, pp 81-114). Typical yields of this branched oligomer were 5-15 A 260 units (15-25%). The complement dA 10 for thermal denaturation studies was obtained from Dalton Laboratories (Toronto, Canada).
iv) Thermal Denaturation Profiles.
Absorbance versus temperature profiles of the nucleic acid complexes were measured at 260 nm using a Varian Cary I UV-VIS spectrophotometer equipped with a variable temperature cell holder controlled by an external variable temperature circulating bath. Data were collected with the spectrophotometer set on dual beam optical mode to reduce optical drift. The data were collected at 260 nm at 0.5 ° C. intervals with an equilibration time of 60s for each measurement point. Absorption coefficients of the branched molecules were assumed to be similar to their corresponding linear sequences and were calculated from those of mononucleotides and dinucleotides according to the nearest-neighbor approximation (Puglisi, J. D.; Tinoco, I., Jr. In Methods in Enzymology; Dahlberg, J. E., Abelson, J. N., Eds.; Academic Press, Inc.: San Diego, 1989; Vol. 180, 304.). Samples for thermal denaturation analysis were prepared by mixing the pyrimidine containing strand with the target (2 mM), lyophilizing the solution to dryness, and dissolving the oligomers in 10 mM Tris, 50 mM MgCl 2 , pH 7.3 adjusted with HCl. The mixtures were then transferred to Hellma QS-1.000-104 cells. Oligonucleotide solutions were heated to 80° C. for 15 min and then slowly cooled to room temperature prior to melting experiments. Normalized plots were constructed according to the method of Kibler-Herzog et al. (Kibler-Herzog, L.; Zon, G.; Whittierm, G.; Shaikh, M.; Wilson, W. D. Anti - Cancer Drug Des . 1993, 8, 65.) based on {(A t −A o )/(A f −A o )}: where A o is the initial absorbance, A f is the final absorbance and A t is the absorbance at any temperature. All complexes showed sharp melting transitions. The melting temperature (T m ) was determined from the first derivative of each thermal curve. A precision in T m values, determined from variance in repeated experiments, of ñ0.5° C. or better was obtained for all of the denaturation profiles investigated.
v) Instrument Setup and Fluorescent Measurements
The laser radiation exiting the immersion lens of the fluorescence microscope (as described in Example 9) was coupled into a delivery fiber of similar numerical aperture (0.48) aligned beneath the objective, as illustrated in FIG. 4 ( c ). The light was totally internally reflected along the delivery fiber to a sensing fiber functionalized with immobilized oligonucleotide. Coupling of the radiation between fibers was achieved by abutting the distal terminus of the delivery fiber to the proximal terminus of the sensing fiber. A loss in optical transmission of no greater than 2% was observed for the coupled system. The termini of the teflon fiber coupler were designed as compression-fit ends which provided a solution-tight seal that prevented contaminants from diffusing into the fiber coupler and causing drift in the analytical signal. The sensing fiber was placed in a small volume, stop-flow, stainless steel hybridization chamber (1.5 mm i.d.×48 mm) which provided a solution volume of 79 μl exposed to the sensing fiber. The temperature of the hybridization cell was controlled by placing the cell in a thermostated housing in which glycol solutions from external variable temperature circulating baths were made to flow. The temperature of the solutions in the hybridization cell were accurately determined (±0.2° C.) by use of a glass encapsulated thermistor incorporated into the hybridization cell and in contact with the solution at the exit of the hybridization chamber. Solutions containing hybridization buffer, ethidium bromide, and complementary nucleic acid sequences were delivered to the hybridization cell and sensing fiber by use of a peristaltic pump. Fluorescence emission from ethidium bromide that was intercalated into immobilized nucleic acid complexes was totally internally reflected within the sensing fiber. The portion of the light coupled back into the delivery fiber was directed towards the microscope objective where it was collimated and directed to the dichroic mirror. The fluorescence radiation was of longer wavelength (λ max =595 nm) than the dichroic cut-off, and was transmitted through the mirror and directed towards a photomultiplier tube, where the fluorescence intensity could be quantitatively measured. Drift caused by variations in the efficiency of optical coupling, laser intensity and photomultiplier gain were obviated by normalization of all signals to that of a standard solution of ethidium bromide at 25° C. prior to and at the completion of each analysis.
vi) PAGE Mobility Retardation Assay.
The solutions of oligonucleotides were lyophilized to dryness, incubated in 10 μL of 30% sucrose with 50 mM MgCl 2 at 75° C. for 15 min., and then cooled to room temperature slowly. After a 4 day incubation at 4° C., the samples were loaded onto the gel. The running buffer contained 90 mM tris-borate buffer (pH 8.0). The non-denaturing 15% polyacrylamide gels contained 90 mM tris-borate (pH 8.0) and 50 mM MgCl 2 . The native gels were run at 12.5 mA for 12 h. Following electrophoresis, the gels were covered with Saran Wraps and photographed with a Polaroid MP4 Land Camera over a fluorescent TLC plate (Merck, distributed by EM Science, Gibbstown, N.J.) illuminated by a UV lamp (Mineralight lamp, Model UVG-54, San Gabriel, Calif.). Instant Sheet Film (#52, medium contrast, ISO 400/21° C.) was used and the exposure (f4.5, 1.5s) made through a Kodak Wratten gelatin filter (#58). The gels were subsequently stained for 5 min in a 5 μg/ml solution of ethidium bromide and destained in distilled water for 30s. The gels were then covered with Saran Wrap®, illuminated by a UV lamp and photographed (f4.5, 2s) through a Hoya orange filter over a white background.
vii) Parallel and Antiparallel TAT Triplex Considerations.
In the formation of the intermolecular triplex 2×dT 10 /dA 10 triplex, the third dT 10 strand interacts by means of Hoogsteen hydrogen bonds with the dA 10 strand in target Watson-Crick duplex, and is oriented parallel to it. In melting experiments (Mg +2 buffer), the triplex 2×dT 10 /dA 10 has two clearly resolved transitions, one for dissociation of the third strand from the duplex, i.e., dT 10 *dA 10 /dT 10 →dT 10 +dA 10 /dT 10 (T m 18° C.), and one for dissociation of the duplex into its component strands, i.e., dA 10 /dT 10 →dA 10 +dT 10 (T m 32° C.). Thus for this complex, association of the third (dT 10 ) strand with the duplex (dA 10 /dT 10 ) is thermodynamically weaker than duplex formation itself.
Branched oligonucleotides are useful probes for stabilizing triplex DNA (R. Hudson, A. Uddin, and M. Damha J. Am. Chem. Soc ., 1995, 117, 12470.). The branched oligomer 1 (FIG. 15) for instance, binds to dA 10 to give a novel TAT triple-stranded complex in which both dT 10 strands are antiparallel to the purine (dA 10 ) strand. Although this motif had been observed for TAT bases in complexes dominated by pur·pur/py bonding (e.g. G·GC, A·AT) ({i} Moser, H. E.; Dervan, P. B. Science , 1987, 238, 645. {ii} Strobel, S. A.; Doucettestamm, L. A.; Riba, L.; Housman, D. E.; Dervan, P. B. Science , 1991, 254, 1639 {iii} Hoogsteen, K. Acta Crystallogr . 1959, 12, 822-823; (b) Felsenfeld, G.; Davies, D. R.; Rich, A. J. Am. Chem. Soc . 1957, 79, 2023-2024; {iv} R. Hudson, A. Uddin, and M. Damha J. Am. Chem. Soc ., 1995, 117, 12470.), it had not been observed previously for dT n /dA n complexes. The formation of this triplex was induced by linkage of two dT 10 strands through their 5′ ends via coupling to riboadenosine at the neighboring 2′ and 3′ oxygen atoms (FIG. 15 ). This arrangement causes the initial direction of the two dT 10 strands to be parallel, and forces the formation of a triplex in which the third dT 10 strand runs antiparallel to the dA 10 strand, and is bound to it via reversed-Hoogsteen interactions. Thermal denaturation profiles of a mixture of 1 and dA 10 (1:1) in Mg +2 buffer, show a single transition from bound to unbound complex, consistent with its formation involving one rather than two bimolecular reaction steps, i.e., 1+dA 10 →triplex 1/dA 10 ) (T m 35° C.).
viii) Triplex Studies Using Derivatized Optical Fibers with Normal (Fiber-3′-dA 10 -5′) Oligonucleotide Orientation.
Characterization of the triple-helical complexes via thermal denaturation studies were done. The dA 10 was grown in the conventional 3′-to-5′ direction from the fiber surface. Solutions of ethidium bromide, ethidium bromide with dT 10 , or ethidium bromide with 1, were heated in the hybridization chamber containing the decaadenylic acid functionalized optical fibers. Upon slow cooling, fluorescent measurements were taken at various temperatures. FIG. 16 ( a ), illustrates that as the dT 10 :dA 10 duplex was formed by lowering the temperature, there was an increase in the fluorescence intensity corresponding to ethidium bromide intercalation and quantum yield enhancement of the ligand in this complex. After further lowering of the temperature, we observed a decrease in the fluorescence intensity with decreasing temperature, indicative of exclusion of the ligand as a result of triplex formation (2×dT 10 :dA 10 ). This process is illustrated in FIG. 7 ( a ). In order to verify that triplex formation was alone responsible for the exclusion of the ethidium cation and hence the decrease in fluorescence intensity from the fiber, a control experiment was done using optical fibers functionalized with a twenty-nucleotide probe sequence of mixed base composition incapable of forming triplex structures. The hybridization experiment was done using the same methodology as for the decaadenylic acid functionalized fibers with the exception of the hybridization buffer (1M NaCl, 50 mM PO 4 , pH 7.0). Having this nucleic acid sequence and buffer composition, only double-stranded complexes could form between the immobilized probe sequence and the complementary sequence. As can be seen in FIG. 6, a fluorescence intensity with a negative temperature coefficient was observed for the duplex system over the temperature range studied. The denaturation temperature for this system of nucleic acids and hybridization buffer was determined to be 73° C. by UV-visible thermal denaturation studies. Only double-stranded complexes existed over the temperature range investigated, as indicated by the enhanced fluorescence intensity for the experiment using the ethidium bromide and complementary oligonucleotide. The control experiment with ethidium bromide and no complementary oligonucleotide showed no such dramatic increase in intensity.
Upon exposure of the optical sensor to the reversed-Hoogsteen forming 1, no significant increase in fluorescence intensity over that of the ethidium bromide alone in solution was observed. The geometrical constraints of compound 1 are such that, if a complex is formed with the immobilized dA 10 strand in this particular (fiber-3′→5′) orientation, the branch-point riboadenosine should be oriented toward the fiber surface thus presenting a steric barrier to triplex formation. In order to test whether steric interference surrounding the branch-point prevented triple-helical formation, an optical fiber having a dA 10 strand in the opposite orientation from the surface (i.e. fiber-5′→3′) was synthesized.
ix) Triplex Studies Using Derivatized Optical Fibers with Reversed (Fiber-5′-dA 10 -3′) Oligonucleotide Orientation.
From FIG. 16 ( b ), the fluorescent intensity versus temperature profile indicated that with dT 10 there was an initial increase in fluorescence indicative of duplex formation. This was followed by a decrease in the intensity which was indicative that triplex formation had occurred. Upon treatment of the optical sensor with 1, a decrease in fluorescence intensity for the reverse Hoogsteen complex at temperatures below the T m (35° C.) was observed FIG. 16 ( c ), which is consistent with triplex formation. From the data of Scaria and Shafer (Scaria, P. V.; Shafer, R. H. J. Biol. Chem ., 1991, 266, 5417), it can be inferred that a temperature below 25° C. is required for the ethidium cation exclusion process to dominate the fluorescence intensity. Given that the quantity of ethidium cation that can be accommodated by triplexes is lower than that for duplexes (where intercalation occurs once every 2.8 base triplets and once per 2.4 base pairs at 25° C.) a 14% reduction in the amount of intercalated ethidium upon triple-strand formation results (Scaria, P. V.; Shafer, R. H. J. Biol. Chem ., 1991, 266, 5417). However, within the triplex structure the fluorescence quantum yield of the intercalated ethidium cation has been observed to increase by 19% for the S 1 →S 0 transition, thereby resulting in an overall change in fluorescence intensity of +2.3%. Therefore, direct correlation between the T m for triplex formation and the onset of decreased fluorescence intensity from the optical sensor will be observed for systems of nucleic acids which have T m values at or below 25° C. This is consistent with our findings, FIGS. 16 ( a and b ) where the decrease in fluorescence intensity from the sensor correlates well with the 17° C. T m for triplex formation. As can be seen in FIG. 16 ( c ), although the transition for triple-strand formation between 1 and the immobilized dA 10 occurs at 35° C., a decrease in fluorescence intensity was not observed until the system was cooled to below 25° C. In this regard, our fluorescence studies involving ethidium bromide binding to triple-helices is in full agreement with several earlier findings. However, our system is then limited in terms of being able to identify only the duplex to triplex transition temperature for nucleic acid systems with T m values at or below 25° C.
x) PAGE Mobility Retardation Assay.
Gel-shift experiments provided us with the opportunity to confirm the interaction of ethidium bromide with the complexes observed in these studies. The electrophoretic mobility of the Watson-Crick base paired dT 10 /dA 10 duplex, (both the Hoogsteen and reverse-Hoogsteen paired TAT triplexes, and that of their component strands), was studied at 4° C. in a buffer containing magnesium. Following electrophoresis, the gels were visualized by UV shadowing, and by staining with ethidium bromide, as shown in FIGS. 17 ( a and b ), respectively. The Hoogsteen triplex migrated more slowly than the duplex due to the presence of the third dT 10 strand. The reversed-Hoogsteen triplex has the slowest mobility of all, and is characteristic of branched nucleic acid structures [ref Hudson and Damha, JACS 1993; Wallace, J. C.; Edmons, M. PNAS vol. 80, 950-954, 1983). Association of 1 and dA 10 was quantitative as evidenced by the complete disappearance of compound 1 and dA 10 , when mixed in equimolar amounts. The stoichiometry of interaction between dT 10 and dA 10 for the duplex and Hoogsteen triplex was also confirmed by studies at different concentrations of the two oligonucleotides. When the gel shown in FIG. 17 ( a ) was stained with ethidium bromide and illuminated by a UV lamp, fluorescence was observed only in the bands corresponding to the complexes (not single strands). This is consistent with the well-known intercalation mechanism of ethidium bromide (Lim, C. S. BioTechniques , 1994, 17, 626.). As previously suggested by the biosensor studies, the 1/dA 10 reverse Hoogsteen triplex gave the lowest fluorescence intensity, which could be related to the limited ability of ethidium to bind to this complex.
Example 15
Optical Sensors Which Function by the Intrinsic Mode of Operation
Background
Angularly dependent light scattering experiments were done to determine the refractive index of oligonucleotide monolayers covalently immobilized onto fused silica substrates. With knowledge of the refractive index of the immobilized oligonucleotide film, the mode of operation of the devices, namely, intrinsic or evanescent total internal reflection fluorescence, can be elucidated. The concept of the experiments done is based on classical optical theory with respect to how alterations in the direction of a ray or collimated beam of light traversing an interface between two dielectric materials may be predicted based on the difference in the refractive index of the two materials, and vice versa. In particular, Snell's law of refraction states that for a ray of light traveling in a plane normal to that defined by the interface between two materials of refractive index n 1 and n 2 , the angular trajectory of the transmitted ray, θ t , from the normal to the interfacial plane will differ from that of the incident ray, θ i , by a quantity dependent on the difference in refractive index of the two materials. This can be solved for mathematically using the following equation (Ohanian, H. C.; Physics, W. W. Norton and Company, New York (1985) p. 837):
n 1 ·sin(θ i )=n 2 ·sin(θ t ) (4)
FIG. 18 ( a ) illustrates this concept for the case where the upper medium is fused silica and the lower medium is the ambient, as characterized by n Fused Silica and n Ambient , respectively, where n Fused Silica >n Ambient . As shown in FIGS. 18 ( a ) and 18 ( b ), as the angle of incidence is increased, the angle of the refracted beam will be deflected by increasing amounts toward the interface, where at all times θ i <θ t . t. This trend is continued to the point where the refracted beam is directed into the interfacial plane (i.e. θ t =90°). The angle of incidence for which this occurs is known as the critical angle, θ c , and can be calculated from the following relation: θ c = sin - 1 ( n Ambient n Fused Silica ) ( 5 )
For the case where θ i ≧θ c , the incident ray undergoes total internal reflection (TIR) at the interface. The angle of the reflected beam with respect to the normal to the interface is then equal to that of the angle of incidence for all θ i ≧θ c , as illustrated in FIG. 18 ( c ).
If a detector for optical radiation was placed directly beneath the intersection point of the light ray with the interface and intensity was recorded as a function of incidence angle, a continuously decreasing intensity with increasing incidence angle would be observed. This observation is the result of the refracted beam being increasingly deflected out of the optical axis of the detector. An illustration depicting the trends in detector response is included on the right hand side of each ray diagram in FIGS. 18-20. As the refracted beam closely approaches the interface between the two dielectric materials, a local maxima in the detector response would be observed as a result of the beam being scattered by surface roughness and other imperfections at the interface. This would continue until θ i =θ c , after which point the incident beam would undergo TIR and hence provide negligible amounts of signal to the detector, with the exception of that which leaks out via scatter from imperfections at the interface and within the waveguiding media. As such, the critical angle for TIR can be determined directly from this point on the plot of scatter intensity versus incidence angle (FIG. 18 ( c )). For the case where the refractive index of one of the media is known, the refractive index of the other can be solved using equation (5).
A three-layer model must be considered for the case where a thin film of organic material is placed at the interface, as shown in FIGS. 19 and 20. Each medium type is herein characterized by the refractive index of the material, as given by n Fused Silica , n Film , and n Ambient , respectively, for the fused silica, organic film, and ambient. The interaction of a light ray at each interface must be considered independently. An incident ray in the fused silica medium at an angle θ i , relative to the interfacial normal will be refracted to a differing angle after traversing each interface. The propagation angle of the ray will then be θ t film , and θ t Ambient in the organic film and ambient media, respectively, relative to the interfacial normal.
For the case where n Fused Silica >n Film >n Ambient , the reciprocal trend will be observed with respect to the propagation direction of the refracted rays, where θ i <θ t film <θ t Ambient , as shown in FIG. 19 . As θ i is increased, a local maxima in the detector response will be observed as θ t Film passes through the critical angle for TIR at the film-ambient interface. This is illustrated in FIG. 19 ( b and c ). A second local maxima will be revealed as θ i passes through the critical angle for TIR at the fused silica-film interface, as shown in FIG. 19 ( d ). Given n Fused Silica and n Ambient , the refractive index of the organic film can be directly determined from analysis of traces of scatter intensity versus θ i . The critical angle for the TIR at the fused silica-film interface can be directly obtained from the point where the second local maxima intersects the baseline scatter intensity, as described previously for the two-layer model and shown in FIG. 19 ( d ). By substituting θ c Fused Silica/Film and n Fused Silica into equation 5, n Film can be solved for directly. Verification of this result can be acquired by substituting the calculated value of n Film and n Ambient , and into equation 5 to determine the value of θ c Film/Ambient . Using the value of θ i from the point where the first local maxima intersects the baseline scatter intensity, n Fused Silica , n Film and equation 4, a second method for calculating θ c Film/Ambient is provided. The goodness of agreement between the two values of θ c Film/Ambient would indicate the validity of the calculated value of n Film .
For the case where n Fused Silica <n Film >n Ambient , an estimate of the value for n Film may be attained provided the values of n Fused Silica , n Ambient are known. A direct determination of n Film cannot be achieved in this case as TIR will not occur at the interface between the fused silica and organic film for light incident in the fused silica, yielding no mechanism for the determination of θ t Film . The ray diagrams and detector response trends for this scenario are shown in FIG. 20. A slight underestimate for the value of n Film may be had by assuming that θ c Film/Ambient is equal to the value of θ i at the termination point of the local maxima from the plot of scatter intensity versus incidence angle. This overestimate of θ c Film/Ambient and n Ambient can be used in equation 5 to provide an underestimate of the value of n Film . This value of n Film along with those for N Fused Silica and θ i can then be substituted into equation 4 to provide an underestimate of θ c Film/Ambient . This underestimate of θ c Film/Ambient and n Ambient can again be used in equation 5 to provide an overestimate of n Film . An average of these two values should provide a good estimate of the true value of n Film to within the uncertainty limits set by the low and high value extremes.
Materials and Methods
Planar Suprasil® fused silica wafers (Heraeus Amersil, Duluth, Ga., USA) with dimensions of 10×5×1 mm, a refractive index of 1.46008 and a surface flatness of 10 waves/inch, were functionalized with substrate linker molecules by the methods of examples 2 and 3. Similarly, silicon wafers (Heraeus Amersil, Duluth, Ga., USA) with dimensions of 10×5×1 mm were functionalized with substrate linker molecules by the methods of example 3. Polythymidilic acid icosanucleotides were then assembled onto the functionalized wafers by automated solid-phase oligonucleotide synthesis, as per the methods provided in example 5. All water used in the light scattering experiments was obtained from a Milli-Q 5 stage cartridge purification system (Millipore Corp., Mississauga, ON, Canada) and had a specific resistance not less than 18 MΩ·cm. The hybridization buffer was the same as that used for hybridization experiments on optical fibers and described in example 8. The refractive index of the hybridization buffer was determined by use of an Bausch & Lomb Abbe-3L Refractometer (Fisher Scientific, Nepean, ON, CA) to within the reported accuracy of 0.0001. Octadecyltrichlorosilane (OTS), ethylene glycol, hexadecane, carbon tetrachloride, chloroform and cyclohexane were of analytical grade or better from Aldrich Chemical Co. (St. Louis, Mo., USA) and used as received unless stated otherwise.
OTS functionalization of fused silica wafers
Fused silica wafers were cleaned by treatment with solutions of NH 4 OH/H 2 O/H 2 O 2 and HCl/H 2 O/H 2 O 2 respectively, as per the method detailed in example 2 (i). Prior to use, carbontetrachloride and chloroform were dried by reflux over P 2 O 5 under an argon atmosphere followed by distillation under the same conditions. Functionalization of the substrates with OTS monolayers was then done as per the methods of von Tscharner and McConnell (von Tschamer, V. and McConnell, H. M., Biophys. J ., 36 (1981) 421) and as described in the following. The cleaned substrates were treated with a solution of 80% hexadecane, 12% carbon tetrachloride, 8% chloroform and 0.1% OTS (v/v) for 15 minutes at 25° C. with stirring under an anhydrous argon atmosphere. The reaction mixture was then decanted and the functionalized fused silica wafers were then washed thrice with distilled chloroform and stored in-vacuo and over P 2 O 5 until required.
Instrumentation used for Light Scattering Experiments
Wafers were placed in a custom-built stop-flow cell, beneath a Harrick EA 7×89 fused silica hemispherical prism with a radius of 8 mm (Harrick Scientific Corp., Ossington, N.Y., USA), as illustrated in FIG. 21 . Optical contact between the fused silica hemispherical prism and fused silica wafer functionalized with an oligonucleotide monolayer was made by applying a thin film of fluorescence free Zeiss Immersionsoel 518C refractive index matching oil (n=1.515, Carl Zeiss Canada Ltd., Don Mills, ON, CA) at the interface between the two. The other face of the wafer was exposed to a solution compartment with dimensions of 9×2×1 mm (l×w×h). The flow cell was mounted at the vertex of a modified goniometer element obtained from a type 43702-200E Thin Film Ellipsometer (Rudolph Research Corporation, Flanders, N.J., USA) with an angular accuracy and precision of 0.005°. 543 nm optical radiation from a Gre-Ne™ Laser (Melles Griot, Carlsbad, Calif., USA, 1 mW output power, 1.5 mm beam diameter, 0.01 mrad beam divergence) mounted on one arm of the goniometer was passed through the hemispherical prism and impinged on the planar fused silica wafer. The hemispherical prism guaranteed that alterations in the incidence angle owing to refraction at the air-prism interface were eliminated as the beam invariably entered the prism normal to the prism/air interface. A M062-FC03 Slo-Syn stepping motor (Superior Electric Co., Bristol, Conn., USA, 200 steps per revolution) was coupled via a set of gears to the screw shaft of the goniometer used to drive the pivoting mechanism of the goniometer arms. The gear ratio used provided the motor with a 7× mechanical advantage so as to reduce the load on the motor and prevent it from slipping. TTL signals from a standard PC parallel interface were used to operate the advance mechanism of the stepper motor so as to offer accurate control of the angle of the goniometer arms and incidence of the laser beam. One end of a fiber-optic bundle (Oriel Corp, Stratford, Conn., USA, model no. 77533) was mounted in the base of the flow cell ca. 1 mm from the exposed face of the fused silica wafer. The other terminus of the fiber bundle was directed to a 630 nm long-pass colloidially-colored glass filter (Schott Glass Technologies, Duryea, Pa., USA) placed before the window of an R-928 photomultiplier tube (Hamamatsu Corp., Bridgewater, N.J., USA) operated using a DZ-112 Photoelectric Indicator (Rudolph Research, Flanders, N.J., USA). The long-pass filter provided for attenuation of the light intensity transmitted by the fiber bundle by a factor of 10 5 . This was done in order to prevent an overload condition in the PMT form occurring, guarantee the linearity of response and preserve the useful lifetime of the detector. The current from the PMT was converted to an analog voltage output (0-5 VDC) from the signal processing electronics contained within the Photoelectric Indicator and passed to a 12 bit analog to digital converter (Metra-Byte, Taunton, Mass., USA) for data acquisition on a PC computer using software created in-house to acquire plots of intensity versus incidence angle.
Results and Discussion
In order to test the validity of the light scattering approach for refractive index determination, samples of known refractive index were introduced into the flow cell beneath the hemispherical prism and analyzed by ramping the incidence angle of the laser mounted on the goniometer arm from low to high incidence angles while recording the observed scatter intensity. The results of experiments done using samples of air (n=1.0003), water (n=1.33), and cyclohexane (n=1.4266) are shown in FIG. 22 ( a-c ), respectively and summarized in Table 2. Knowing the refractive index value of the prism material (fused silica, n=1.46) and the analyte, equation 5 was used to determine the critical angle values for TIR in each system. Good correlation with the predicted values was observed in all three cases with no more than 1% error between the experimental and theoretical values for θ c . An unmodified fused silica wafer was then coupled to the base of the prism and the same three control samples were again analyzed. Identical results within the resolution of the experimental technique were observed between the theoretical and observed values of critical angle for analyses done with and without the fused silica wafer. This indicated that no additional modifications to the instrument or correction factors would need be applied as a result of moving the intersection point of the laser beam 1 mm below the base of the prism. Hybridization buffer (n=1.35) was also analyzed by the light scattering method (FIG. 22 ( g )) and provided good agreement with the calculated value for θ c , based on the refractive index of the buffer as determined using a standard Abbe refractometer.
TABLE 2
Summary of the Results from the Angularly Dependent Light
Scattering Experiments and Correlation with Controls of Known
Refractive Index.
Experimental
Calculated
Interface Type
η Ambient
θ c
θ c
% Error
Fused Silica Prism - Air
1.0003
42.8°
43.2°
0.9
Fused Silica Prism - Water
1.33
65.6°
65.6°
0.0
Fused Silica Prism -
1.427
77.8°
77.8°
0.0
Cyclohexane
Fused Silica Prism -
1.35
67.7°
67.6°
0.1
Hybridization Buffer
Fused Silica Wafer - Air
1.0003
43.2°
43.2°
0.0
Fused Silica Wafer - Water
1.33
65.6°
65.6°
0.0
Fused Silica Wafer -
1.427
77.9°
77.8°
0.1
Cyclohexane
Experiments were then done using films of organic media of known refractive index in order to test the validity of the technique as applied to the previously described the three-layer model. Thin films (10-50 μm) of refractive index matching oil and ethylene glycol were applied to the exposed surface of the hemispherical prism and analysis was then done where air was used as the ambient in both cases. The results of the light scattering experiments for these samples are shown in FIGS. 23 a and 23 b , respectively. As can be seen in FIG. 23 a , the experimentally determined value of θ c Film/Ambient =41.7° for the oil-air interface, based on a value of θ i of 43.5°, and that predicted from theory, well agree after taking into account refraction of the beam upon traversing the fused silica—oil interface. However, for this particular example, the two-step approximation method for determination of n Film cannot be used in this example. The first assumption that θ i =θ t used in this treatment leads to a first estimate of n Film which is lower than that of n Fused Silica . This would lead to the result that the transmitted beam in the oil would be refracted away from the normal as opposed to towards the normal, as would be the case for n Film >n Fused Silica . This causes the next approximation of n Film to be a more exaggerated underestimate of the true value. As such, films of refractive index slightly greater than that of the fused silica substrate cannot be solved for.
The results for the light scattering experiment using an ethylene glycol film provided very good agreement between the values of θ c at each interface with respect to that calculated from theory. Of significance in this plot of scatter intensity versus incidence angle is the appearance of two distinct maxima. The observation of the two maxima concurs with that proposed for the three-layer model (FIG. 19) for the case where n Fused Silica >n Film >n Ambient . As such, information with regard to whether the refractive index of the organic film is greater than or less than that of the substrate material can be obtained by quick inspection.
A monolayer film of OTS was covalently attached to the surface of a fused silica wafer by a method previously shown to provide dense surface packing and a theoretical refractive index in the range of 1.4-1.6. ({a}Ducharme, D. et al., J. Phys. Chem, 94 (1990) 1925. {b} von Tscharner, V. and McConnell, H. M.; Biophys J., 36 (1981) 421). The results of the light scattering experiments are shown in FIG. 23 ( c ) and 23 ( d ), respectively, for OTS functionalized fused silica wafers exposed to air and water as the ambient. Using the following rearrangement of equation 5: n Film = n Ambient sin θ c Film / Ambient ( 6 )
the value of the refractive index for the OTS monolayer could be solved for. Values of 1.44 and 1.45 for the refractive index of the monolayer were determined from the analyses using air and water as the ambient, respectively. Given that the refractive index values determined for the OTS monolayer differed by ˜1% with that of the fused silica substrate, the same limitation as observed for the refractive index matching oil layer applies herein. As such, it can only be assumed that the refractive index of the OTS overlayer is only slightly greater than that of the fused silica. This is reinforced by the fact that of only one local maxima in the plot of scatter intensity versus incidence angle was observed. If the film refractive index was indeed less than that of the fused silica substrate then two local maximas should have been observed, in accord with the three-layer model concept and as clearly demonstrated by the experiment using ethylene glycol for the film (FIG. 23 ( b )).
Samples of fused silica wafer functionalized with substrate linker molecules by the methods of example 2 and 3 onto which polythymidilic acid icosanucleotides were assembled by the method of example 5 were analyzed by the angularly dependent light scattering technique. The results of the analysis are shown in FIG. 24 ( a ) and 24 ( b ) for samples prepared by the mesylate activation scheme as detailed in example 3. The results for samples prepared by the GOPS-HEG protocol given in example 2 are shown in FIG. 24 ( c ). For the samples prepared by mesylate activation for which water and 3:1 ethylene glycol in water solution was used as the ambient, a value of 1.57 was determined in both cases for the underestimate of n film , based on the assumption that θ t Film =θ i . Subsequent to the recalculation of θ t Film based on the underestimated value of n Film , overestimates for n Film of 1.67 and 1.68, respectively, were determined from the cases where water and 3:1 ethylene glycol in water were used as the ambient. This provided an average value for n Film of 1.62±0.05. Similarly, analysis of the fused silica wafer functionalized with polythymidilic acid icosanucleotide on GOPS-HEG substrate linkers (example 2) yielded an average value for n Film of 1.48±0.01. The fact that estimates of n Film for both types of nucleic acid—substrate linker overcoating could be solved for strongly reinforces the fact that these overlayers on the fused silica substrates indeed possess a larger value of refractive index than that of the substrates onto which they are immobilized.
In addition to the light scattering experiments, ellipsometry was done in order to provide secondary confirmation of the experimentally determined values of the refractive index for the oligonucleotide monolayers. Ellipsometry was done on samples of silicon wafer functionalized with substrate linker molecules by the methods of example 3 onto which molecules of polythymidilic acid icosanucleotide were assembled by automated solid-phase oligonucleotide synthesis as detailed in example 5. Silicon wafers were necessarily used as the substrate material for these experiments as the fused silica substrates used for the light scattering experiments provide little reflection of the laser beam incident at an angle 70° in the ambient. The surface of the silicon wafers was made similar to that of fused silica via the cleaning procedure used prior to functionalization of the substrate. This cleaning procedure is known to provided a layer of oxidized silicon at the surface of the silicon wafers (Kern, W. and Puotinen, D. A.; RCA Review, 31 (1970) 187-206). As such, silanol moieties then present at the oxidized silicon-ambient interface provide attachment points for the substrate linker molecules.
McCracken (F. L. McCracken, NBS Technical Note 479, Washington D.C. (1969)) has developed software capable of providing values of thickness and refractive index from ellipsometric measurements of thin films using the exact Drude equations for ellipsometry. The Film 85 software provided with the AutoEL-II null reflection ellipsometer (Rudolph Research Corp., Flanders, N.J., USA) was based on that originally developed by McCracken and used for the analysis of ellipsometric data from the experiments described herein. Ellipsometric analysis of the cleaned substrate revealed the formation of a 20 Å thick layer of oxidized silicon on the surface of the wafers. Three silicon wafers functionalized with substrate linker and oligonucleotide where then analyzed. Ten different locations on the wafer surfaces were chosen at random and the results of the ellipsometric analysis are summarized below in Table 3.
TABLE 3
Results of Ellipsometric Analysis of Oxidized Silicon Substrates
Functionalized with Substrate Linker Molecules by the Methods of
Example 3 and Polythymidilic Acid Icosanucleotide by the Methods of
Example 5.
Film
Corrected
Refractive Index
Refractive
Film Thickness (Å)
Estimated Using the
Index for a
Estimated Using the
Iterative Calculation
Film of
Sample
Iterative Calculation
Method of
100Å
Number
Method of Program 12.
Program 12.
Thickness.
1
84
2.090
1.76
2
103
1.764
1.81
3
113
1.372
1.55
4
108
1.402
1.51
5
75
2.115
1.59
6
72
2.189
1.58
7
76
2.091
1.59
8
82
2.129
1.75
9
81
2.119
1.72
10
73
2.132
1.56
Average Value ± σ
1.6 ± 0.1
As can be seen by inspection of the data shown in Table 3, determination of thickness and refractive index concurrently via the iterative process provides a large degree of variation. This is based largely on the fact that the covalently immobilized nucleic acid membrane system is not ideal for ellipsometric analysis in that it violates many of the assumptions of the Drude equations. Of particular significance is the fact that a densely packed oligonucleotide film with the nucleic acid strands oriented perpendicular to the air-film boundary would be uniaxially anisotropic. This would cause alterations in the speed of the p- and s-polarized components of the light beams upon passage through the oligonucleotide film. This effect has been known to produce relative errors in thickness of up to 10% (R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light , North Publishing Company, New York (1977)).
A better estimate of the refractive index of the immobilized nucleic acid films may be achieved by application of Maxwell-Garnet theory (R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light , North Holland Publishing Company, New York (1977), p. 359). The concept of Maxwell-Garnet theory, as applied herein, is based on the notion that a partially formed monolayer film of coverage Θ is optically equivalent to a fully formed monolayer film of refractive index (n Film ) and relative thickness (T f ) such that the observed film thickness (T) is related to that of the fully formed film by:
T=ΘT f (7)
Likewise, the same scaling factor, Θ, can be applied to the refractive index value given from ellipsometric analysis so that values more representative of that for the actual immobilized layers can be obtained. The results after applying this correction are given in Table 3 and provided an average value of 1.6±0.1 for n Film .
The good correlation between the result of the light scattering experiments and ellipsometry provides unequivocal evidence that monolayers of oligonucleotides can be assembled onto substrate linker functionalized fused silica substrates of higher refractive index than that of the substrate material. Oligonucleotides assembled onto fused silica wafers functionalized with substrate linker molecules via the mesylate activation scheme, as outlined in example 3 were observed to provide immobilized nucleic acid monolayers with a refractive index of 1.62±0.05 by light scattering investigations. This correlated well to the refractive index value of 1.6±0.1 obtained by ellipsometric investigations. Light scattering investigation of oligonucleotides assembled onto fused silica wafers functionalized with substrate linker molecules via the methods of example 2, revealed a nucleic acid film refractive index of 1.48±0.01, which also is higher than that of the fused silica substrates onto which they are covalently attached. As such, optical sensors created by the methods reported herein will then function by and provide the signal throughput advantages associated with the intrinsic TIRF motif described previously.
The present invention has been described in terms of particular embodiments found or proposed by the present inventor to comprise preferred modes for the practice of the invention. It will be appreciated by those of skill in the art that, in light of the present disclosure, numerous modifications and changes can be made in the particular embodiments exemplified without departing from the intended scope of the invention. All such modifications are intended to be included within the scope of the appended claims.
All publications, patents and patent applications are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety. This application also claims priority from U.S. application Ser. No. 60/050,970 and Canadian application no. 2,208,165, both of which are incorporated by reference. | A biosensor for direct analysis of nucleic acid hybridazation by use of an optical fiber functionalized with nucleic acid molecules and fluorescence transduction is disclosed. Nucleic acid probes are immobilized onto the surface of optical fibers and undergo hybridization with complementary nucleic acids introduced into the local environment of the sensor. Hybridization events are detected by the use of fluorescent compounds which bind into nucleic acid hybrids. The invention finds uses in detection and screening of genetic disorders, viruses, and pathogenic micoorganisms. Biotechnology applications include monitoring of gene cultures and gene expression and the effectiveness (e.g. Dose-response) of gene therapy pharmaceuticals. The invention includes biosensor systems in which fluorescent molecules are connected to the immobilized nucleic acid molecules. The preferred method for immobilization of nucleic acids is by in situ solid phase nucleic acid synthesis. Control of the refractive index of the immobilized nucleic acid is achieved by the support derivatization chemistry and the nucleic acid synthesis. The preferred optical fiber derivation yields a DNA coating of higher refractive index than the fiber core onto the fiber surface. |
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a reflective audio assembly and combination of such assembly with a picture frame.
Various audio visual combinations have been proposed in the past in which a picture, for example of a person, is displayed in a picture frame which is associated with some form of sound reproducing means which is capable of playing back a personalized audio message from the person shown in the picture. One such combination is shown, by way of example, in my prior U.S. Pat. No. 3,857,191. In that Letters Patent several embodiments of picture frame and sound reproducing mechanisms capable of reproducing utterances by the person displayed in the picture are disclosed. In general, each of these embodiments includes the combination of a picture frame which receives and displays a personal picture and a housing associated with the frame which contains certain specific audio playback mechanisms for playing back the personalized message through a speaker in the housing. The speaker may either be directed to the front of the frame or the sides or the rear of the housing. In each of these embodiments, the speaker is located directly behind perforations, either in the frame itself or in the housing.
In a reflective audio assembly and personalized audio visual combination incorporating the principles of the present invention, the quality of the sound emanating from the assembly or combination is substantially enhanced and improved and is more natural and realistic than in audio visual combinations of the prior art. In a reflective audio assembly and personalized audio visual combination incorporating the principles of the present invention, the sound is first introduced to a sound receiving enclosure in which it reflects before being emitted toward the front of the assembly and beneath the picture and into contact with a planar surface, such as the table upon which the assembly is supported, all substantially enhancing the tonal and directional qualities of the sound. A reflective audio assembly and personalized audio visual combination incorporating the principles of the present invention may be self supporting, may house the sound reproducing components needed to reproduce the audio desired, and may provide rapid and easy access to such components either for maintenance or use.
In one principal aspect of the present invention, a reflective audio assembly comprises a housing having a top wall, a bottom wall, side walls and a front wall and these walls define a sound receiving enclosure. Support means supports the enclosure on a substantially planar surface and means for mounting a sound speaker are provided so as to direct the sound from the speaker into the enclosure at a location spaced from the front wall of the enclosure. The front wall has an opening therein which includes sound deflecting means which deflects the sound which leaves the opening from the enclosure downwardly toward the surface upon which the housing is supported.
In another principal aspect of the present invention, the front wall is inclined at an obtuse angle relative to the bottom wall of the housing to deflect the sound which leaves the opening downwardly toward the planar surface upon which the housing is supported.
In still another principal aspect of the present invention, the assembly includes picture frame means and the frame means defines at least a portion of the top wall of the sound receiving enclosure.
In still another principal aspect of the present invention, the front wall opening of the aforementioned assemblies is adjacent the bottom of the picture frame means.
In still another principal aspect of the present invention, in the aforementioned assemblies, a second enclosure may be provided adjacent the sound receiving enclosure, the second enclosure may be defined at least in part by one of the aforementioned walls and the second enclosure contains sound reproducing means.
In still another principal aspect of the present invention, a personalized audio visual combination of a picture receiving frame and housing is provided. The frame includes means for receiving and displaying a picture. The housing supports the frame on a substantially planar surface for display of the picture and the housing includes a plurality of walls defining a sound receiving enclosure including a front wall adjacent the bottom of the frame. Means is provided for mounting a sound speaker to direct the sound from the speaker into the enclosure at a location spaced from the front wall of the housing and an opening in the front wall includes sound deflecting means which deflects the sound which leaves the opening from the enclosure in the direction in which the picture is displayed and downwardly toward the planar surface upon which the combination is supported.
In still another principal aspect of the present invention, in the aforementioned combination, the opening is beneath the picture frame.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
In the course of this description, reference will frequently be made to the attached drawings in which:
FIG. 1 is an overall, perspective view of a personalized audio visual combination incorporating the principles of the present invention supported upon a flat surface, such as a table top;
FIG. 2 is a cross-sectioned, side elevational view of the combination shown in FIG. 1 and showing the housing thereof in cross-section as viewed substantially along line 2--2 of FIG. 1;
FIG. 3 is a cross-sectioned plan view of the housing as viewed substantially along line 3--3 of FIG. 2; and
FIG. 4 is an overall perspective view of the housing from which the picture and sound reproducing components have been removed for purposes of clarity and in which the front wall of the housing is partially laterally displaced for access to the interior of the housing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is directed to a reflective audio housing, generally 10, and the combination thereof with a picture frame, generally 12, as shown in FIG. 1.
The housing 10 generally comprises a pair of side walls 14 and 16, as shown in FIGS. 3 and 4, a bottom wall 18, as shown in FIGS. 2 and 4, an intermediate wall 20 which is angled relative to the bottom wall 18, as also shown in FIGS. 2 and 4, a top wall 22 and a rear wall 24. The housing also includes a pair of front walls 26 and 28, as shown in FIGS. 2-4. The front wall 26 extends upwardly from the bottom wall 18 at an obtuse angle, as best viewed in FIG. 2 and as will be described in more detail to follow.
The intermediate wall 20 defines the top wall of a sound receiving enclosure 30, as shown in FIG. 2, together with the side walls 14 and 16, the bottom wall 18 and the front wall 26, the lower front of the front wall and a pair of generally triangular front side walls 31. The sound receiving enclosure 30 receives the sound which is transmitted by a conventional speaker 32, as shown in FIG. 2. As shown in FIGS. 2 and 4, the speaker 32 is preferably mounted adjacent wall 20 in overlying relationship to and facing an opening 34 in that wall and in spaced relationship to the obtusely angled front wall 26. Front wall 28 includes an enlarged opening 33 adjacent its bottom beneath wall 20 and facing the front of the assembly to allow sound, as shown by the dotted lines in FIG. 2, to leave the sound receiving enclosure 30. Before the sound passes from the portion of the sound receiving enclosure 30 underlying the speaker to the obtusely angled front wall 26, it is repeatedly reflected within the sound receiving enclosure. Following several such reflections, the sound leaves an elongate opening 36 in wall 26 so as to emanate frontally beneath the picture P which is displayed in the frame 12 and is deflected downwardly against the surface S of the table or other substantially planar surface upon which the combination is supported due to the obtuse angle of the front wall 26 and its opening 36. Thereby, the quality of the sound, both from the standpoint of tone as well as direction, is substantially enhanced to the listener who is positioned in front of the picture P. The quality of the sound is additionally enhanced due to the reflection which takes place within the sound receiving enclosure 30 prior to the sound emanating downwardly from the elongate opening 36.
It will be seen that a portion of the top wall of the sound receiving enclosure 30 prior to discharge of the sound from opening 36 may be defined by the bottom 38 of the picture frame 12, as shown in FIG. 2.
The bottom wall 18 also preferably defines a support for the housing 10 and picture frame 12 such that the housing 10 supports the frame in use. For this reason, the wall 28 is preferably somewhat inclined so as to support the frame upright, but at a slightly reversed incline for ease of viewing. It will be understood that the bottom wall 18 may support the assembly directly on its bottom planar surface or upon feet or other elements which may be mounted upon or otherwise attached to the bottom wall 18.
The top wall 22 and lower intermediate wall 20, together with the upper portions of the side walls 14 and 16, the rear wall 24 and the front wall 28 define a sound reproducing enclosure 39 for receiving the speaker 32, as well as the sound reproducing means, generally 40, of the invention, as best shown in FIGS. 2 and 3. By way of example, the sound reproducing means 40 may include a magnetic audio tape cassette playback assembly which, in addition to the speaker 32, may comprise a cassette playback chassis 42, a motor 44, a battery 46, a pinch roller assembly 48, a fly wheel 50, a capstan 52, a playback or record/playback head 54, a drive belt 56, a conventional audio cassette 58 and other components of a cassette playback or record/playback assembly. The particular details of such cassette assembly are not part of the present invention and may be readily selected by those skilled in the art after considering the foregoing description of the invention.
It will thus be seen that the intermediate wall 20 of the housing 10 constitutes a major portion of the top wall of the sound receiving enclosure 30 and also the bottom wall of the sound reproducing enclosure 39 which contains the sound reproducing means 40. The speaker 32 is mounted adjacent intermediate wall 20 and is positioned to direct the sound through the speaker opening 34 and into the sound receiving enclosure 30 for reflection therein. Thus, the housing 10 provides an integral unit which contains both the sound receiving enclosure 30 and the sound reproducing enclosure 39.
The top wall 22 may also include a removable cover or hatch 60, as shown in FIGS. 1, 2 and 4, for accessing the cassette 58. In addition, a removable cover or hatch 62 may also be provided, as shown in FIGS. 2 and 3, for replacement of the battery 46. Suitable openings 64 and 66 may also be positioned through one of the walls into the sound reproducing enclosure 39, for example in the back wall 24 as shown in FIG. 3, for access to an on-off switch 68 and volume control 70.
The front wall 28 is preferably mounted to the housing 10 such that it may be slidably removed to gain access to the sound reproducing enclosure 39 and sound reproducing means 40 for servicing of the latter. One manner in which this may be accomplished is shown in FIGS. 2 and 4 wherein the front wall 28, which is preferably of substantially the same width as that of the frame 12, may be slidably received in elongate grooves 72 in the top wall 22 and bottom wall 18 of the housing. The front wall 26 may be formed integrally with or attached to the bottom of wall 28, as best seen in FIG. 4. The opposite edges of the front wall 28 may include screw holes 74, as shown in FIGS. 1 and 4, by which the front wall 28 and its housing 10 may be attached to the rear of the frame 12 to form an integral combination therewith, with the frame 12 resting upon front wall 26 to form part of the top wall of the sound receiving enclosure 30.
With the foregoing description of the preferred embodiment in mind, the sound from speaker 32 is projected into the sound receiving enclosure 30 in which it is reflected several times, as shown by the dotted lines in FIG. 2, before it emanates from the opening 36 in the front wall 26 of the enclosure. As the sound emanates from the forward facing opening 36 it is further deflected downwardly due to the obtusely inclined opening 36 and its wall 26 so that the sound is reflected from the surface S upon which the combination rests and toward the listener who is viewing the picture P. Such reflections, both within the sound receiving enclosure 30 and off of the surface S, substantially improve both the tonal, particularly the bass tonal quality, as well as directional quality of the sound to give the impression that the picture itself is talking. Moreover, because the sound is directed into the sound receiving enclosure 30, rather than frontally from the frame, a larger speaker may be employed which is capable of reproducing better bass response.
It will be understood that the embodiment of the present invention which has been described is merely illustrative of one of the applications of the principles of the present invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention. | A reflective audio assembly and picture frame defines a personalized audio visual combination. The frame displays a picture and a housing supports the frame in a substantially upright condition on a planar surface such as a table. The housing includes a sound receiving enclosure for receiving the sound from a speaker of a tape sound reproducing assembly which may also be contained in the housing. The sound receiving enclosure includes a front wall having an opening therein which is directed towards the front of the picture and downwardly to deflect the sound toward the planar surface upon which the combination is supported to enhance the tonal and directional qualities of the sound. |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of the international application PCT/FR2004/000836, filed on Apr. 2, 2004, which designated the United States of America, the entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The invention relates to a filter block and to a filter body formed by the assembly of a plurality of filter blocks, used for the filtration of particles present in the exhaust gases of an internal combustion engine, particularly of the diesel type.
Conventionally, before being released to the open air, the exhaust gases may be purified by means of a particulate filter like the one shown in FIGS. 1 and 2 , known in the prior art.
A particulate filter 1 is shown in FIG. 1 in a transverse cross section, along a cutting plane B-B shown in FIG. 2 , and, in FIG. 2 , in a longitudinal cross section along the cutting plane A-A shown in FIG. 1 .
The particulate filter 1 conventionally comprises at least one filter body 3 , inserted in a metal housing 5 , intended to be traversed from an upstream side 7 to a downstream side 9 , by the exhaust gases.
The filter body 3 generally comprises a plurality of filter blocks 11 a - 11 i consisting of porous honeycomb structures, conventionally made from ceramic (cordierite, silicon carbide), assembled together by bonding by means of seals 12 of ceramic cement. The seals 12 , substantially gastight, are conventionally about 1 mm thick. The ceramic cement generally consists of silica and/or silicon carbide and/or aluminum nitride.
The assembly thus formed can then be machined to the desired cross section, round or ovoid for example. The filter body 3 shown in FIGS. 1 and 2 has the shape of a cylinder with an axis C-C.
Among the filter blocks, a distinction is made between the internal filter blocks 11 i and the external filter blocks 11 a - 11 h . Unlike the internal filter blocks 11 i , the external filter blocks 11 a - 11 h are adjacent to the housing 5 . Conventionally, a material 12 ′, gastight to the exhaust gases, is placed between the external filter blocks 11 a - 11 h and the housing 5 .
Conventionally, a filter block 11 a - 11 i is substantially a rectangular parallelepiped, with length L, width l and height h. It comprises a plurality of straight, parallel channels 13 , adjacent to one another, and with the same square cross section. The internal space 14 of a channel 13 is bounded by a side wall 17 terminating outwardly in an opening 19 and blocked, at the end opposite the opening 19 , by a plug 20 .
Two types of channels are distinguished. The inlet channels 13 e comprise a plug 20 e on the downstream side 9 and an opening 19 e on the upstream side 7 . The outlet channels 13 s comprise a plug 20 s on the upstream side 7 and an opening 19 s on the downstream side 9 .
The inlet channels 13 e and outlet channels 13 s are arranged alternately, in the width 1 and in the height h of the filter block.
As shown in FIG. 2 , the exhaust gas stream F enters the filter body 3 via the openings 19 e of the inlet channels 13 e , passes through the side walls 17 of these channels to reach the outlet channels 13 s , and escapes to the exterior via the openings 19 s . The expression “filtration zone” of a side wall 17 is the area of this wall crossed by the exhaust gases.
Every passage of the gases through the filter block is accompanied by a pressure drop, mainly due to the passage of the gases through the filtration zones. It is desirable to minimize this pressure drop.
For the same gas flow rate entering the filter, the pressure drop is generally lower when the filtration zones of the channels are extended. In fact, a large filtration zone means, for an inlet channel, a large area available for the passage of the gases, and, for an outlet channel as well as an inlet channel, generally a large cross section limiting the pressure drop during the flow of the gases in the channel. However, a compromise is necessary to take account of the size, weight and cost requirements. To optimize this compromise, the filter is therefore adapted according to the pressure drop permissible in its application.
Patent application FR 0104686, filed by the Applicant, also proposes a filter body comprising a central part and a peripheral part having different channel densities and suitable for balancing the pressure drop at various points of the filter body.
Despite these improvements, a permanent need exists for solutions permitting a further reduction of the pressure drop across the filter while meeting the size requirements.
The object of the invention is to provide a filter block suitable for limiting the pressure drop resulting from the crossing of the filter by the gases.
SUMMARY OF THE INVENTION
According to the invention, this aim is achieved by means of a filter block for the filtration of particles present in the exhaust gases of an internal combustion engine, comprising a group of flow channels for said gases, each of said channels being bounded by a wall provided with a filtration zone and terminating outwardly in an opening, said group of channels comprising at least two channels of which the respective F/P ratios between the filtration zone area F and the wall area P are different. The filter block according to the invention is remarkable in that a channel of said group of channels has an opening whose area O is larger, the larger the area F of said filtration zone of said channel.
As shown in greater detail in the rest of the description, the adaptation of the opening of a channel as a function of the area of its wall used for filtration, in particular the adaptation of the openings of the peripheral channels of which the F/P ratios are different from 1, tends to make the gas velocities in the channel and in the plurality of the channels adjacent to it uniform, thereby facilitating the flow of the gases through the filter. An advantageous result thereof is a lower pressure drop.
According to other preferred features of the invention,
every channel of said group is conformed so that
0.9 *R threshold <O/F <1.1 *R threshold , (I)
and preferably so that
O/F=R threshold (II)
where R threshold is a threshold value, determined for example according to the intended application of said filter block;
said group only comprises channels terminating near one another, or only inlet channels, or only outlet channels for said gases, or further comprises all the channels of said filter block; said channels of said filter block being substantially parallel, adjacent to one another, and classifiable as “peripheral” channels and as “internal” channels according to whether they do or do not comprise, respectively, a nonfiltering zone exposed toward the outside of said filter block, the ratio O p /O i of the area O p of the opening of a peripheral channel to the area O i of the opening of an internal channel adjacent to it is between 0.2 and 0.75. Two channels are said to be “adjacent” when they comprise a common portion of side wall, possibly in the form of a common edge. In the latter case, the portion of common side wall is limited to a contact line. Preferably, when said peripheral channel is a corner channel, that is, extending along a longitudinal edge of said filter block, the ratio O p /O i is between 0.2 and 0.3, and further preferably is substantially equal to 0.25. Preferably, when said peripheral channel is a lateral peripheral channel, that is, is positioned along a single side of the filter block, said O p /O i ratio is between 0.4 and 0.6, and preferably is substantially equal to 0.5; the cross sections of said inlet and/or outlet internal channels, in a plane perpendicular to the direction of said channels, are all identical or are different according to whether a channel is an inlet channel or an outlet channel.
The invention further relates to a filter body intended for a particulate filter, and comprising at least one filter block according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The description that follows, provided with reference to the drawings appended hereto, will allow a better understanding and appreciation of the advantages of the invention. In these drawings:
FIG. 1 shows a particulate filter of the prior art, in a transverse cross section along the cutting plane B-B shown in FIG. 2 ;
FIG. 2 shows the same particulate filter, in a longitudinal cross section along the cutting plane A-A shown in FIG. 1 ;
FIG. 3 shows a view of the upstream side 7 of a filter block according to the preferred embodiment of the invention.
In these figures, which are nonlimiting, the various components (walls, seals, filter blocks, plugs) are not necessarily shown at the same scale. Identical numerals have been used in the various figures to designate identical or similar elements.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 having been described in the introduction, we shall now refer to FIG. 3 .
The plugs 20 s of the outlet channels 13 s are shown cross-hatched.
A distinction is made between the internal channels 25 and the peripheral channels 27 .
The internal channels 25 have a square transverse cross section, that is, in a plane perpendicular to the direction C-C of the channels, each side of the section having a length L p . The internal channels 25 terminate outwardly in openings having an area O i . The four sides 25 a , 25 b , 25 c and 25 d of the side wall 17 i of an inlet or outlet internal channel 25 are each adjacent to an outlet or inlet channel, respectively. The area F i of the filtration zone of the side wall 17 i is hence formed by the four sides 25 a - 25 d , and is thus substantially equal to the area P i of this wall. Thus F i /P i ≅1.
The peripheral channels 27 comprise at least one side adjacent to the exterior of the block. Among the peripheral channels 27 , a distinction is made between the corner channels 27 ′ and the side channels 27 ″. The corner channels 27 ′ extend along the longitudinal edges 29 of the filter block. The side channels 27 ″, unlike the corner channels 27 ′, are positioned along a single external side 31 of the filter block. The corner 27 ′ and side 27 ″ peripheral channels terminate outwardly in openings having areas O p ′ and O p ″, respectively.
The corner channels 27 ′ have a square cross section, each side having a length l p . The side channels 27 ″ have a rectangular cross section, the length of the small side being equal to l p , and the length of the large side being equal to L p .
The side walls of the corner channels 27 ′ and of the side channels 27 ″ have respective areas P p ′=L.4.l p and p p ″=L.(2.l p +2.L p ). They comprise two sides, 27 a ′ and 27 b ′, and one side 27 a ″, respectively, adjacent to the exterior of the filter block, the other sides 27 c ′ and 27 d ′, and 27 b ″, 27 c ″ and 27 d ″, respectively, being adjacent to other channels.
As described in the introduction, the filter blocks 11 a - 11 i are joined to one another by a cement seal 12 substantially gastight to the exhaust gases to be filtered. The peripheral channels 27 of the external filter blocks 11 a - 11 h of the filter body 3 adjacent to the housing 5 are isolated from the exterior by the material 12 ′ gastight to the exhaust gases.
The external sides 27 a ′ and 27 b ′ on the one hand, and 27 a ″ on the other, in contact with the seal 12 , or the gastight material 12 ′ hence prevent the passage of the gases to be filtered and are nonfiltering zones of the side walls of the channels 27 ′ and 27 ″, respectively. The filtration zones of the side walls of the channels 27 ′ and 27 ″ therefore have areas F p ′ and F p ″, respectively, formed by the other sides 27 c ′ and 27 d ′, and 27 b ″, 27 c ″ and 27 d ″, respectively, and therefore equal to L.2.l p and L.(L p +2.l p ), respectively.
Let us consider a group of channels comprising at least two channels of which the respective F/P ratios between the filtration zone area F and the wall area P are different, for example, a group of channels comprising an internal channel 25 , a corner peripheral channel 27 ′ and a side peripheral channel 27 ″.
F p ′/P p ′≠F p ″/P p ″≠F i /P i
According to the invention, a channel of said group of channels has an opening whose area O is larger, the larger the area F of said filtration zone of said channel. Since F p ′<F p ″<F i , we therefore have O p ′<O p ″<O i .
Preferably, every channel of said group is conformed so that
0.9 *R threshold <O/F< 1.1 *R threshold , (I)
where R threshold is a threshold value, preferably further so that
O/F=R threshold . (II)
Thus, in a preferred embodiment of the invention, R threshold =O p ′/F p ′=O p ″/F p ″=O i /F i . In other words, R threshold =l p .l p /(L.2.l p )=l p .L p /(L.(L p +2.l p ))=L p .L p /(L.4.L p ), leading to l p =0.5.L p .
Hence, O p ′=l p .l p =0.25.L p .L p =0.25.O i , and O p ″=L p .l p =0.5.L p .L p =0.5.O i
According to the invention, the O p ′/O i ratio is hence preferably between 0.2 and 0.3, preferably substantially equal to 0.25, and the O p ″/O i ratio is between 0.4 and 0.6, preferably substantially equal to 0.5.
It is assumed that the stream of gas to be filtered arrives at a substantially uniform velocity at the upstream side 7 of the filter block shown in FIGS. 1 , 2 and 3 .
The cross section of the channels of the filter blocks according to the prior art ( FIGS. 1 and 2 ) is adapted to optimize the compromise between size and pressure drop during the passage of the gases entering and exiting via the internal channels 25 . In other words, the internal channels 25 , particularly their openings, are conformed so that the pressure drop during the filtration of the gas is lower than but close to a permissible limit pressure drop.
According to the prior art, the inlet and outlet peripheral channels generally have identical openings to those of the inlet internal channels, but lower filtration zone areas. The filtration zones of the inlet peripheral channels hence do not suffice to filter all the gas arriving at the openings of the peripheral channels, thereby causing an overpressure upstream of these openings and a detrimental pressure drop. Moreover, the outlet peripheral channels, receiving less filtered gas than the internal channels, have oversized openings.
According to the invention, the area of the openings of the peripheral channels is reduced to take account of the fact that the filtration zone, which does not cover the entire area of their side wall, is itself reduced in comparison with that of the internal channels.
The flow rate of gas entering or exiting a channel being substantially proportional to the area of the opening of this channel and the area of this opening being adapted to the filtration zone of the channel, the invention makes the gas velocities uniform in the various channels. The pressure drop caused by the filter is therefore reduced.
The adjustment of the openings of the peripheral channels results in a gain in volume which can be exploited by adding additional internal channels. At equivalent size, a filter block according to the invention hence gives rise to a lower pressure drop than that caused by a filter block of the prior art. At identical pressure drop, a filter block according to the invention is more compact than a filter block of the prior art.
Generally, the incident gas stream is not uniform, and in particular, the pressure of the incident gas is different depending on the location of the channel concerned in a filter block and depending on the location of the filter block within the filter body.
In this situation, it is therefore advisable to apply the formulas (I) and (II) only to a group of channels limited to channels of which the openings are crossed by gas streams arriving with substantially identical composition and/or pressure. Preferably, the group of channels is therefore limited to channels terminating near one another.
Preferably, the O p /F p ratio of a peripheral channel is such that
0.9 *O′ i /F′ i <O p /F p <1.1 *O′ i /F′ i , (III)
where O′ i denotes the area of the opening of an internal channel adjacent to said peripheral channel, F′ i is the area of the filtration zone of said internal channel. Preferably, said adjacent internal channel is a channel of the same type as said peripheral channel.
Obviously, the present invention is not limited to the embodiments described and shown above, which are provided for illustration and are nonlimiting.
Thus, the invention further relates to a monolithic filter body. The filter block could have any shape whatsoever.
The cross section of the channels is not limited to the square shape. The cross section of the inlet channels could also be different from that of the outlet channels. The general shape of the cross sections of the peripheral channels could further be different from that of the cross sections of the internal channels. The transverse cross section of a channel could also vary periodically or not, along this channel.
Finally, the opening of a channel could also not be plane or could not be perpendicular to the axis of the channel. | A filter block for filtering particles contained in the exhaust gas of an internal combustion engine includes a plurality of channels for the circulation of the gas, a channel defined by a wall provided with a filtering zone and which opens out towards the outside via an opening, a group of channels including at least two channels with different respective F/P ratios between surface F of the filtering zone and surface P of the wall. One channel of the group of channels includes an opening whose surface O is larger than the surface F of the filtering zone of the channel. |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of International Application PCT/US06/012289, filed Apr. 4, 2006, which claims the benefit of U.S. provisional patent application No. 60/668,306 filed on Apr. 4, 2005, each of which is incorporated by reference in its entirety herein.
BACKGROUND OF THE INVENTION
A “smart” payment card is a type of plastic card embedded with a computer chip that stores and transacts data between users. The computer chip includes a microprocessor and memory, or only a memory chip with non-programmable logic. The data is associated with either value or information or both and is stored and processed within the card's chip. The card data is transacted via a reader that is part of a computing system. It can contain more data than a magnetic stripe card and can be programmed to reveal only the relevant information. For example, it could tell a device in a store that there is sufficient balance in an account to pay for a transaction without revealing the balance amount. Encryption techniques secure the data, and the processor allows it to be programmed for different applications. Smart cards are now widely deployed, for example, in healthcare, banking, entertainment and transportation industries. There are two general categories of smart cards: contact and contactless smart cards. A contact smart card requires insertion into a smart card reader with a direct connection to a conductive micromodule on the surface of the card. It is via these physical contact points, that transmission of commands, data, and card status takes place. A contactless card requires only close proximity to a reader. Both the reader and the card have matching radiofrequency antennas providing a contactless electromagnetic link by which the two can communicate.
The smart cards are fabricated, for example, by embedding a micro module into the plastic substrate or card. Contactless smart cards may be fabricated by laminating the antenna/chip module between top and bottom card layers. The antenna is typically 3-5 turns of very thin wire or conductive ink connected to the contactless chip.
The industrial fabrication and the properties of smart cards are subject to voluntary industry standards. A basic smart card standard is the ISO 7816 series, part 1-10. These standards are derived from the financial ID card standards and detail the physical, electrical, mechanical, and application programming interface to a contact chip card. For example, the ISO 7816-1 Standard limits the physical size of the card. The card is the ID-1 size: (85.6 mm×54.0 mm×76 mm). This is the same size as a bank credit card. The standard includes accommodation of exposure limits for a number of electromagnetic phenomena such as X-rays, UV light, electromagnetic fields, static electrical fields, and ambient temperature of the card. Furthermore, ISO 7816-1 defines the mechanical characteristics of a card (e.g., when it is bent or flexed) to make sure that plastic cards with embedded chips and antennas are manufactured in a way that guarantees flawless operation over the expected lifetime of a card.
Smart cards deployed, for example, in the payment-by-card industry, also may include features such as magnetic stripes and embossed lettering, so that the cards are operable with legacy payment infrastructure such as magnetic stripe card readers and embossed card paper imprinters that are still in use in the field. Embossing allows for textual information or designs on the card to be transferred to paper by using a simple and inexpensive device. ISO 7811 specifies the embossed marks, covering their form, size, embossing height, and positioning. Use of magnetic stripe technology advantageously reduces the flood of paper documents associated with embossing. ISO 7811 also specifies the properties of the magnetic stripe, coding techniques, and positioning.
The smart cards, may be fabricated by laminating a foil or inlay, which, for example, supports a chip and antenna, into a PVC plastic card. A laminating press may be used adjust the pressure applied to the cards. Too much pressure on a contactless inlay can break the antenna, rendering the contactless feature useless.
Consideration is now being given to ways of providing solutions for improving card fabrication. Attention is directed to reducing variations in the physical properties of the cards consistent with commonly accepted standards. In particular, attention is directed to improving standard compliance procedures.
SUMMARY OF THE INVENTION
The invention provides a system and method for payment card quality assurance. The system and method use a grid or similar graphic to optically accentuate card surface feature or deformations. The system and method may be used to qualify card-manufacturing processes. The invention allows for identification, prior to volume manufacture, of a deformation in the card that may result in unacceptable quality cards.
The grid or similar graphic enables a generic test that checks the quality across the whole card. This whole card testing can replace multiple tests for each card specific graphic, thus reducing testing time and costs.
Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of payment card and a grid pattern that accentuates surface features of the card, in accordance with the principles of the present invention. The payment card may be standard size (e.g., ID-1 size). The grid dimensions may be about half a millimeter or less.
FIGS. 2 and 3 are schematic illustrations of the specification parameters for the geometrical location of the antenna and the PICC module in a contactless payment card, respectively.
FIG. 4 is an illustration of an exemplary process monitor card fabricated with a grid pattern, which has a spacing of about half a millimeter, for inspecting compliance with inlay layout specifications, in accordance with the principles of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a system and method for payment card quality assurance (QA). This system and method employ a grid pattern or similar pattern, which optically amplifies or accentuates surface features, for the inspecting the surfaces of product payment cards. FIG. 1 shows an exemplary grid pattern 110 . Grid pattern 110 preferably blankets the entire card surface, which allows the entire card surface to be inspected for defects or deformation quickly, for example, in plan view.
The grid pattern may be designed to exploit diffraction, lenticular, or other optical phenomena for amplification of the surface features. The grid pattern may be applied to the surfaces of the subject test cards using an adhesive tape or sticker. Alternatively the grid-like pattern may be generated by optical elements (e.g., screens) in a plan view optical inspection system.
In an exemplary application of the invention, process monitor cards are processed through same fabrication steps used for product payment cards. (See e.g. FIG. 1 , process monitor card 100 ). The process monitor cards are fabricated to have a surface grid pattern 110 or similar pattern, which optically amplifies surface features. The grid pattern or other similar pattern makes plan view inspection of surface defects easier. The process monitor cards may be used to qualify the fabrication process to ensure that the product payment cards fabricated by the process are in compliance with standard industry or any other desired product specifications.
An exemplary application of the inventive QA system and method is described herein with reference to the manufacture of contactless or proximity-only payment cards that are fabricated by laminating an inlay together with plastic sheets. The process monitor cards may be fabricated, for example, by using a plastic sheet that has a printed or built in grid pattern as an overlay sheet in the laminate.
The inlay, which may be a discrete or virtual layer inside the payment card, carries an antenna and the integrated circuit module (PICC). The design of the inlay may be according to ID-1 specifications. A product specification may, for example, define acceptable card thickness outside embossed areas and add-on areas. The thickness of the inlay is such that it allows the generation of a card within a defined product specification.
The antenna and the PICC are geometrically laid out to avoid card areas that are designated for other card features, such as embossed characters, holograms, magnetic stripes, etc. FIGS. 2 and 3 show graphically the specification parameters for the location of the antenna and the PICC module, respectively. With reference to these figures, Tables II and II show exemplary values for the specification parameters for the antenna and PICC module layout respectively.
TABLE I
Layout Specifications for Antenna Exclusion Area
e1
Distance from the left edge of the card to
6.13 +
6.13
the left edge of the antenna exclusion area
(2.54*n]
e′1
Id, first character of Name and address area
8.67
8.67
not printed
e2
Distance from the left edge of the card to
76.50
8.9
the right edge of the antenna exclusion area
h1
Distance from the bottom of the card to the
24.03
ns
bottom edge of the antenna exclusion area
h2
Distance from the bottom of the card to the
6.04
6.04
top edge of the antenna exclusion area
(fourth line shall not be used)r
h′2
Distance from the bottom of the card to the
9.63
9.63
top edge of the antenna exclusion area
(third and fourth lines shall not be used)r
TABLE II
Layout Specifications for PICC Exclusion Area
m1
Distance from the top of the card to the top
18.79
maxi
of the PICC module exclusion area
m2
Distance from the bottom of the card to the
6.04
maxi
bottom of the PICC module exclusion area [3
lines embossed on the address area]
m′2
Distance from the bottom of the card to the
9.63
maxi
bottom of the PICC module exclusion area [2
lines embossed on the address area]
n1
Distance from the left edge of the card to
5.15
maxi
the left edge of the PICC module exclusion area
n2
Distance from the left edge of the card to
82.12
mini
the right edge of the PICC module exclusion area
n3
Height definition of the ICC Contact area
24.03
mini
available for PICC module location
n4
Width definition of the ICC Contact area
25.00
mini
available for PICC module location
p
Reverse side: Distance from the right edge
25.00
mini
of the signature panel to the right edge of the card
where ml => ICC contact area;
m2 => embossing area;
n1 => ICC contact area;
n2 => hologram;
n3 => embossing area; and
n4 => ICC contact area
The product specification may require that the layout appearing on the product payment card should deviate laterally by no more than 0.1 mm as measured against the original image through an optical or electronic device with a magnification of at least 10 times.
In accordance with the invention, the card fabrication process may be qualified by testing process monitor cards. The process monitor cards for quality assurance may be fabricated, for example, by using a plastic sheet, which has a printed or built in grid pattern, as an overlay sheet in the laminate. FIG. 4 shows an exemplary process monitor card fabricated with a plastic sheet having a grid pattern for inspecting compliance with the inlay layout specification. The grid pattern has a suitable spacing (e.g., about half a millimeter).
Other card features, such as embossed characters, holograms, magnetic stripes, etc., are constructed at later or “personalization” steps in the card manufacturing process. These card features or characteristics are also subject to the product specifications. Table III and IV show exemplary product specifications for the surface profile of the magnetic stripe, and for card surface irregularity and roughness. Quality assurance procedures for these features also may be advantageously based on process monitor cards, which have grid patterns on their surfaces to amplify or accentuate the surface features.
TABLE III
Surface Profile of the Magnetic Stripe
Stripe Width and
Vertical
Surface
surrounding
deviation*
Standard
Profile type;
W = 6.35 mm
A < 9.5 μm
ISO 7811-6
Mag area convex
(track 1 & 2)
id
W = 10.28 mm
A < 15.4 μm
(tracks 1, 2 & 3)
Profile type;
W = 6.35 mm
A < 5.8 μm
ISO7811-6
Mag area concave
id
W = 10.28 mm
A < 9.3 μm
Adjacent surface
Surface of the stripe
−5 μm <
ISO 7811-6
to adjacent surface
h < 38 μm
Surrounding
No surface distortion,
19.05 > s >
XYZ . . .
s, measured from the
2.54 mm
top of the card
*The vertical deviation measured on the transverse surface profile of the magnetic stripe
TABLE IV
Surface Irregularity and Roughness
Surface
Surface
Irregularities
Roughness
Standard
Front
Any surface irregularity due
The surface
XYZ
Side
to the antenna and/or module
roughness required
should have height/depth less
for thermal
than 6 mm for a slope (height
transfer printing
to length ratio) lower than
is Ra < .025 mm.
1/400.
Reverse
Any surface irregularity due
XYZ
Side
to the antenna and/or module
should have height/depth less
than 25 mm for a slope
(height to length ratio) lower
than 1/25.
In addition to the desired surface characteristics, payment cards are designed to withstand a number of mechanical stress conditions during their lifetime and to maintain its functionality for the cardholders—at least till their planned expiry dates. The exemplary product card specifications may further include specifications for card characteristics related to mechanical robustness and reliability. The product specification may, for example, specify mechanical or physical characteristics such as bending stiffness, durability, overall card warpage, heat resistance, solidity-peel strength, adhesion or blocking, resistance to surface abrasion, etc. The following mechanical tests are often identified in product specifications as relevant to evaluate the mechanical robustness and reliability of payment cards.
ISO Dynamic Bending Test (2000/4000 cycles). 3-Wheel Test Wrapping Test Tensile Stress Test Corner Impact Test Vibration Test. (e.g., Standard IEC 68-2-6). Rotary Impact Test Combined environmental-mechanical stress test (e.g., temperature-humidity test).
Several of these tests involve visual evaluation of the surface features of the payment card after subjecting the card to mechanical stress. For example, the Vibration Test involves visual inspection to confirm absence of deformation or cracks up on completion of the test protocol. The 3-Wheel and Impact Tests involves visual inspection to of the test card to note appearance of superficial crackles or breaking of the plastic material. It will be readily understood that the process monitor cards fabricated with surface grid patterns to optically amplify or accentuate the surface features of the cards can be advantageously used to simply visual inspection in the aforementioned and other tests.
It will be further understood that the foregoing is only illustrative of the principles of the invention, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. | A system and method for payment card quality assurance is provided. The system and method use a grid or similar graphic to optically accentuate card surface deformations in test cards. The grid enables a generic test that checks the quality across the whole card surface. Process card monitors with the grid pattern can be used to qualify card-manufacturing processes. |
BACKGROUND OF THE INVENTION
The present invention relates to a new and improved construction of a machine tool containing a machine stand for a work spindle, a tool magazine arranged separate from the machine stand and a tool changer arranged at the tool magazine.
From Swiss Patent No. 580,469 there is known to the art a machine tool of the type containing a machine stand for a work spindle and a tool magazine arranged separate from the machine stand, there also being provided a tool changer arranged at the tool magazine. This machine tool contains a tool changer which consists of a gripper rocker or balance arm which is pivotably mounted at the tool changer, a gripper arm which is pivotably mounted at the gripper rocker, and a gripper vane provided with gripper tongs or claws and rotatably mounted upon the gripper arm. Consequently, the tools both at the work spindle and also in the tool magazine are seized and released, as the case may be, by the gripper tongs with a movement which is perpendicular to the axis of the tool. A movement in the direction of the axis of the tool enables such to be withdrawn out of or inserted into the work spindle, as the case may be.
With this tool changer at least one of the pivotal elements, namely the gripper arm or gripper rocker, must possess a lever arm having a length which is directed towards the path of travel through which moves a tool from the tool magazine to the work spindle. Since there must be moved along with the tool also a gripper vane containing grippers, which collectively have a certain weight, it is possible for larger rotational moments or torques to appear at the pivot shafts or axes. These rotational moments are composed of braking and acceleration moments, which become increasingly greater as there is increased the speed with which the tool change operation is to be accomplished. Since such rotational moments finally are applied at the magazine stand it is necessary for the latter to be constructed so as to be particularly stable and must be braced at the ground. This is also so because the gripper rocker along with the gripper arm and the gripper vane, i.e., practically the entire tool changer must be moved back-and-forth in the direction of the axis of the work spindle, in order to withdraw or insert, as the case may be, a tool out of or into the work spindle.
Also in U.S. Pat. Nos. 3,242,568 and 3,256,600 there are known to the art further machine tools of the previously mentioned type. The provided tool changers are movably arranged in each instance upon a rail which must be secured both at the tool magazine and also at the machine stand.
The drawback of this arrangement resides in the fact that the machine stand, and thus also the tool spindle must be connected with the tool magazine. Therefore, vibrations can be transmitted from the tool magazine via the rail to the machine stand. This, in turn, impairs the working accuracy of the machine. This occurs that much more intensely the closer the tool magazine is arranged at the machine stand, in other words, the smaller the amount of space which is needed by the entire machine tool.
In French Patent No. 2,090,161, there is also disclosed a further machine tool of the previously mentioned type. With this machine tool the tool changer, which likewise contains a carriage which can travel upon a rail, only is attached at the machine stand.
In order to render possible a sufficient work accuracy it is necessary, with this construction of work spindle, to interrupt the machining work during such time as the tool changer, for instance, exchanges a tool in the magazine. This operation reduces the output of such machine.
Furthermore, the position momentarily assumed by the carriage along the rail influences the position of the work spindle, since the machine stand is loaded by a greater bending moment if, for instance, the carriage is dispositioned at the tool magazine.
In French Patent No. 2,303,637 there is taught to the art a machine tool wherein the tool changer, which likewise contains a carriage which can travel upon a rail, and the tool magazine are attached at the magazine stand.
The thus resulting drawbacks are the same as for the equipment design of the machine disclosed in the above-discussed French Patent No. 2,090,161. However, in this case, such disadvantages are more acute.
In French Patent No. 2,307,615 there is disclosed a further machine tool whose construction coincides with the construction of machine tool disclosed in the aforementioned French Patent No. 2,303,637. Hence, here also there prevail the same shortcomings.
Further equipment of the type under discussion has been disclosed in French Patent No. 1,579,286 and the German Patent Publication No. 2,525,212 which exemplify additional state-of-the-art structures.
SUMMARY OF THE INVENTION
Therefore, with the foregoing in mind it is a primary object of the present invention to provide a new and improved construction of a machine tool of the previously mentioned type, which contains a tool changer, and which avoids the aforementioned drawbacks, enables a simple course of movement of the tool changer and eliminates any damaging effect of the tool change operation upon the machining accuracy of the work spindle.
Another and more specific object of the invention aims at providing a machine tool of the previously mentioned type which enables designing the machine stand so as to be simpler in construction and lighter in weight.
Still a further object of the invention aims at providing a machine tool of the character described which allows for a better mutual accommodation of the position of the tool magazine to that of the machine stand, and thus, simplifies the accommodation of the tool changer to different arrangements of such components.
Yet a further object of the invention aims at providing a new and improved construction of machine tool which precludes that vibrations, emanating from the tool magazine, will be transmitted to the work spindle, and thus, impair the accuracy of the operation of the machine tool.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIG. 1 is a front view illustrating part of a machine tool according to the invention;
FIG. 2 is a top plan view of the machine tool shown in FIG. 1;
FIG. 3 illustrates on an enlarged scale in relation to FIG. 1, in top plan view part of the machine tool shown in FIG. 1 and illustrated partially in sectional view; and
FIG. 4 is a fragmentary front view of part of the arrangement of FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Describing now the drawings, in FIGS. 1 and 2 there is illustrated a machine tool 1 composed of a machine stand 2, a tool magazine 3 and a tool changer 4.
As best seen by referring to FIG. 2, the machine stand 2 is mounted to be movable to-and-fro along a substantially horizontal axis 5, in conventional manner upon guides of a base frame. As a matter of simplifying the illustration the base frame containing the guides has been omitted from the showing of the drawings, because it is covered by a bellows 8 and thus protected against contamination or soiling. At the front side 9 of the machine stand 2 there is arranged a work spindle 10. This work spindle 10 contains a conventional device for receiving and chucking the tools. For instance, this device can be designed especially for receiving tools at whose one end there is provided a cone or conical portion of a certain length and having a predetermined aperture angle. The drive of such work spindle 10 is accomplished equally in conventional manner and is unimportant for understanding the teachings of the instant invention. The work spindle 10 also is arranged to be displaceable along a vertical axis 11, as best seen by referring to FIG. 1.
Also by reverting to FIG. 1 there will be recognized a rotatable and displaceable rotatable table 12 upon which there can be chucked the workpieces. The rotatable or rotary table 12 is arranged forwardly of the machine stand 2 and likewise is mounted and driven in known manner along guides.
The tool magazine 3 consists of a magazine stand 13 which is supported upon a magazine socket or pedestal 14 or the like. A further socket portion 15 likewise constitutes part of the magazine socket or pedestal 14. A brace or support member 16 additionally laterally supports the magazine stand 13. Arranged at the magazine stand 13 is a guide rail 17 for a revolving endless chain 20. This endless chain 20 carries holders 21 for the tools 22.
The endless chain 20 is driven by a standard sprocket wheel or gear which, in turn, is propelled by a suitable drive motor. The components composed of the sprocket wheel, drive motor and the control of the drive motor as well as their arrangement and also their use for tool magazines are well known and therefore need not here be further considered.
As best seen by referring to FIGS. 1 and 2 the tool changer 4, apart from the hereinafter described elements, consists of a rail 23 composed of a linear partial portion 24 and a curved portion or section 25. The rail or rail means 23 is provided at both sides with travel surfaces 26, 27, 28 for the rolls 29, 30 and 31, respectively, of a carriage or slide 32. The rolls or rollers 29 and 31 serve for guiding the carriage 32 in horizontal direction and possess vertical and pairwise coaxially arranged wheel axes 33 and 35. The rolls or rollers 30 serve for the vertical guiding of the carriage 32 upon the rail 23 and therefore possess correspondingly horizontally oriented axes or shafts 34. As to each of the rolls 29, 30, 31, two such rolls are arranged along the carriage 32 which travel upon the related travelling surfaces or tracks 26, 27 and 28.
The carriage 32 consists of a carriage frame 36 at which there are mounted the rolls 29, 30 and 31, and in which there is arranged a drive device 37 and upon which there is located a rotary arm carriage or slide 38.
This rotary arm carriage or slide 38 is attached to the carriage frame 36 by means of two cylinder guides 39 arranged at the carriage frame 36. This allows the rotary arm carriage 38 to perform a displacement movement in horizontal direction upon the carriage frame 36.
Mounted upon the rotary arm carriage 38 is a rotatable arm 41 which can rotate about an axis or shaft 40. At both ends of the rotatable arm 41 there is arranged a respective gripper tong or clamp 42 or equivalent structure which is capable of seizing and retaining or again releasing, as the case may be, a tool 22 at whose collar 44 there is arranged forwardly thereof a cone or conical portion 43. The rotary arm carriage 38 along with the rotatable arm 41 and the gripper clamps or tongs 42 constitutes structure known as such in this art and also can be designed in conventional manner, so that further details thereof need not here be given.
As best seen by referring to FIGS. 3 and 4, the drive device or unit 37 consists of a drive motor 45 which is flanged to a drive housing 61 secured at the carriage frame 36, and by means of a shaft 46 drives a sprocket wheel 47. This sprocket wheel 47 is connected by means of a chain 48 with a further sprocket wheel 49 which is rotatably mounted but fixedly connected with a sprocket wheel 50 of smaller diameter upon a shaft 51. A second chain 52 is trained about the sprocket wheel 50 as well as a further sprocket wheel 53 which is fixedly connected and conjointly seated along with the drive gear 55 upon a shaft 54. Suitable as the drive motor 45, in the embodiment under discussion, is a hydraulic motor. Of course, such tool changer also can be equipped with a drive motor which functions according to a different principle. The rail 23 carries within a groove 56 a chain 57 which extends over the entire length of the rail 23. The drive gear or wheel 55 meshes with the chain 57, so that the carriage or slide 32 can be driven. Of course it is possible to use, instead of the chain 57, also other elements or equivalent structure, such as racks and the like. The drive device 37 as well as the chain 57 collectively form the drive means 37, 57.
The rail 23, as best seen by referring to FIGS. 1 and 2, is supported upon the socket portion 15 by means of a frame 58 and a foot member 59.
An extension element 60, which is separate from the rail 23 and secured at the stand 2 and having the same travel surfaces 26, 27 and 28 for the rolls 29, 30 and 31, constitutes an extension of the rail 23 in the direction of the work spindle 10.
Having now had the benefit of the foregoing description of the machine tool arrangement of the present development its mode of operation will be considered and is as follows:
If a tool 22 is to be exchanged at the tool magazine 3 for a tool 65 in the work spindle 10, then the operations needed for this purpose are carried out approximately in the following manner: Initially, the endless chain 20 is brought into a position, as generally indicated by reference character 70, where the desired tool 22 can be engaged by the gripper clamp 42. During the revolving of the endless chain 20 the carriage or slide 32 is located in its park position 66, which has been indicated in phantom lines in FIG. 2. The endless chain 20 can be moved while the carriage 32 assumes this park position 66 without coming into contact with the gripper clamps or tongs 42 of the rotary arm 41.
If the tool 22 has reached the above-described position 70 which has been shown in FIGS. 1 and 2, then the carriage 32 is brought into its end position 62 operatively associated with the tool magazine 3 and as the same has been shown in full lines in FIG. 2. During such time as the carriage 32 moves into the end position 62 one of the gripper clamps 42 engages the tool 22 at the collar 44. Thereafter the carriage 32 travels into its park position 66. At that location the cone or conical portion 43 of the tool 22 can be cleaned by any suitable conventional cleaning means. At a later point in time the carriage 32 travels into its end position 67 operatively associated with the work spindle 10, this end position 67 having been illustrated in FIG. 2 by chain-dot lines. This presupposes that the machine stand 2 and the work spindle 10 are brought into a certain position as shown in FIG. 2, in which the extension piece or element 60 can form the extension of the rail 23 and the work spindle 10 is located at the height of the gripper clamp 42. In this end or terminal position 67 the carriage 32 bears upon the extension piece or element 60. The drive gear or wheel 55 or equivalent structure, on the other hand, is still in engagement with the chain 57 which only extends up to the rail end 68. During arrival of the carriage 32 at the end position 67 the empty gripper clamp or tong 42 has engaged the collar 69 of the tool 65. The rotary arm carriage 38 now can be displaced into its forward end or terminal position 71, so that the tool 65 can be withdrawn out of the work spindle 10.
In the forward end or terminal position 71 of the rotary arm carriage 38 the rotary arm 41 is rotated through 180°, so that now the tool 22 comes to lie in front of the work spindle 10. The rotary arm carriage 38 need now only be retracted back into its rear terminal or end position and the tool 22 is mounted in the work spindle 10. The carriage 32 now is retracted back into its end position 62, so that the gripper clamp 42 can release the collar 44 of the tool 22 and the tool 65 is placed in a holder 21 of the endless chain 20 provided in the tool magazine 3. Now the carriage or slide 32 returns back into the park position 66 and the tool changer is ready to carry out a further tool change operation.
While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. ACCORDINGLY, | With such machine tool the tool magazine is arranged independent of the machine stand. To obtain a tool changer having a simple course of movement which, additionally, does not transmit any vibrations from the tool magazine to the work spindle, the tool changer consists of a slide or carriage which is movably arranged upon a rail. A drive is provided for the carriage for moving the latter upon the rail. The rail is attached at the tool magazine and is extended in length by an extension piece which is arranged at the machine stand. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a container for dispensing flexible material and more particularly to such a container which is uniquely well suited to housing and dispensing flexible ducting in such a manner as to allow the operator to dispense selected lengths of ducting without releasing more than the desired length from the housing.
2. Description of the Prior Art
The storage, transport and dispensing of materials such as used in construction frequently presents very difficult problems. Materials employed at construction sites are commonly very bulky and must be used in quantities which require powered equipment to move them to the precise location desired for use. Conversely, even though the materials are difficult to move, frequently they are relatively fragile and thus loss due to damage is common. Still further, because such materials are difficult to handle, construction workers commonly leave unused materials at the construction site upon completion of the job rather than attempting to recover for subsequent use those materials which are otherwise entirely satisfactory. All of these factors contribute to waste at the job site and increase the cost of construction.
Flexible ducting used in virtually all construction presents these same difficulties. Flexible ducting is employed to handle the movement of air in the heating and cooling systems in virtually all habitable structures including homes, office buildings, factories and the like. Flexible ducting is, essentially, a very lightweight insulated conduit which is both longitudinally and transversely compressible. It can be produced in substantially continuous lengths, but for the sake of convenience is most commonly packaged in corrugated cardboard containers housing predetermined lengths of the ducting.
The ducting is commonly endwardly compressed within the container so that the maximum length of ducting can be housed in the smallest possible container. The compression of the ducting along its longitudinal axis is quite substantial and does not in any way damage the ducting. However, at the job site when such a container is opened for use, the ducting rapidly expands from the container to assume its normal length. Even if all of the length of duct is required for use, this phenomenon presents difficulties. With all of the ducting expelled from the container, it is subject to damage from puncturing, tearing or the like before it is installed. It may also be inconvenient to install when having to maneuver it through confined areas in its fully expanded configuration. It can, of course, at this time also become damaged.
Most commonly, not all of the ducting in one container will have to be employed at one time. While the ducting can easily be severed in the length or lengths desired, the unused portion becomes a problem. If left out of the container, it will likely become damaged or so impregnated with dust, paint, or other construction substances as to become unusable. The container in which it was originally housed may be available for use, but it is very difficult and certainly inconvenient to attempt to force the unused portion of ducting back within the container since this requires recompression of the ducting along its longitudinal axis. In this process the ducting characteristically will buckle and resist reinsertion under compression within the container. This process may itself damage the ducting so as to render it unusable. In other instances, the container may have been so torn apart in opening it that it can no longer house the ducting.
In any case, the result of such problems is that the ducting is simply abandoned at the job site thereby increasing the costs of construction.
Therefore, it has long been known that it would be desirable to have a container for dispensing flexible material having particular utility in the dispensing of flexible ducting and which permits the user to dispense from the container only the length of flexible ducting desired while retaining the remainder thereof within the housing for subsequent use; which preserves the unused portion of the ducting in a protected condition at the job site insulated from damage due to puncturing, tearing or the like or due to dust, paint or other construction materials; and which insures that waste due to abandonment of unused ducting at the job site is reduced to a minimum.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide an improved container for dispensing flexible material.
Another object is to provide such a container which has particular utility in the dispensing of flexible ducting used in construction.
Another object is to provide such a container which is operable to dispense only the length of flexible ducting required for use at any given time during construction while retaining the remainder of the flexible ducting housed therein in protected condition for subsequent use.
Another object is to provide such a container which retains the portion of the flexible ducting housed therein under compression in its original packaged condition.
Another object is to provide such a container which achieves its objectives with little or no additional cost over prior art containers for housing flexible ducting, which is easy to operate without prior instruction, and which does not present a risk of damage to the flexible ducting.
Another object is to provide such a container which operates cooperatively with the inherent properties of the flexible material to accomplish the objectives of the invention.
Another object is to provide such a container which can be constructed in a multitude of different forms and sizes while possessing the same operative advantages.
Another object is to provide such a container which reduces to a minimum the waste associated with the installation of flexible ducting at a job site by insuring that only the length of flexible ducting required for a particular installation is withdrawn from the container at any given time, which prevents damage and contamination of the unused portion of the flexible ducting and which remains in a condition appropriate for transport and storage at all times so as to minimize the chance that it will be abandoned at the job site.
Further objects and advantages are to provide improved elements and arrangements thereof in an apparatus for the purposes described which is dependable, economical, durable and fully effective in accomplishing its intended purposes.
These and other objects and advantages are achieved in the container for dispensing flexible material of the present invention wherein a housing is adapted to receive the flexible material with an end portion in a dispensing position and a control mechanism is borne by the housing overlaying the dispensing position and imparting resistance to the flexible material while permitting the flexible material to be pulled from the housing by the end portion for dispensing in selected lengths.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the container of the first form of the present invention showing, for purposes of illustration, flexible ducting in phantom lines housed therein, with the end flaps of the container in opened attitudes and with a portion of the container broken out to reveal the point of attachment to the container of the securing means of the container.
FIG. 2 is a longitudinal section of the container of FIG. 1 shown in perspective view with a length of flexible ducting housed therein.
FIG. 3 is a perspective view of the container of FIG. 1 shown in a typical operative environment.
FIG. 4 is a fragmentary perspective view of the container of FIG. 1 with the end flaps thereof disposed in closed attitude.
FIG. 5 is a perspective view of the container of the second form of the present invention.
FIG. 6 is a top plan view of the container of FIG. 5 showing the outer end flaps thereof disposed in opened attitudes.
FIG. 7 is a fragmentary side elevation of the container of FIG. 5 taken from a position indicated by line 7--7 in FIG. 6.
FIG. 8 is a somewhat enlarged, longitudinal, vertical section taken from a position indicated by line 8--8 in FIG. 5 and fragmentarily showing a length of flexible ducting therein in the process of being dispensed from the container.
FIG. 9 is a somewhat further enlarged, fragmentary, sectional, perspective view of a flap of the container of FIG. 5 folded into a configuration forming a shoulder operable during dispensing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIRST FORM
Referring more particularly to the drawings, the container of the first form of the present invention is generally indicated by the numeral 10 in FIG. 1. The container has a housing or carton 11 preferably, although not necessarily, constructed of corrugated cardboard. The carton has a pair of substantially parallel side walls 12 joined by front and back walls 13 and 14 respectively to form the box-like carton. The carton has a lower end wall 15 joining the side walls, front wall and back wall and an opposite upper end wall 16. The upper end wall is composed of flaps hereinafter to be described which are shown in FIG. 1 in opened attitudes and in FIG. 2 in closed attitudes.
One of the side walls 12 has a hand opening 17 through which a person's hand can be extended to grasp the side wall for purposes of carrying or maneuvering the carton. A securing means 18 is mounted on the lower end wall 15. The securing means includes a perforation 19 in the lower end wall. A rod 20 is disposed within the carton and lines 21 are tied on the rod and extended through the perforation externally of the carton. The lines 21 are adapted to be secured, where desired, as shown in FIG. 3 on any available structure such as the bar 22 at a construction site for purposes of holding the carton stationary while removing the contents therefrom.
The carton 11 encloses an internal chamber 23 which, for purposes of illustrative convenience, will be understood to have a dispensing position 24 hereinafter to be discussed in greater detail.
The upper end wall 16 of the carton 11, as previously noted, is composed of flaps. The flaps as shown in the drawings and hereinafter described compose a control means or mechanism 30 for the carton 11. The control mechanism includes a first end flap 31 integral with one of the side walls 12 and an opposite second end flap 32 integral with the other of the side walls 12. The control mechanism further includes a lower cover flap 33 borne by and integral with the front wall 13 and an opposite upper cover flap 34 borne by and integral with the back wall 14. The lower and upper cover flaps each have perforations 35 adjacent to the first end flap 31, as shown in FIGS. 1 and 2, to define dispensing flaps 36.
The upper end wall 16 of the carton is formed by the first and second end flaps 31 and 32 being folded toward each other so as to overlay the internal chamber 23, the lower cover flap 33 folded over the first and second end flaps and the upper cover flap 34 folded the opposite direction to overlay the lower cover flap. The upper end wall, so formed, is retained in this configuration to seal the carton with the product in it at the plant by any suitable means including staples, adhesive tape or the like. In use, as will hereinafter be described, the lower and upper cover flaps are torn along the perforations 35 to form the dispensing flaps 36 and folded backwardly. The first end flap 31 is then slipped from beneath the remainder of the lower and upper cover flaps and folded backwardly thus forming a dispensing opening 37. As can best be visualized in FIG. 3, the dispensing opening so formed is defined by the first end flap 31, the dispensing flaps 36 and the edges of the lower and upper cover flaps 33 and 34 respectively formed by tearing along the perforations 35.
The container 10 of the present invention is adaptable to dispensing a variety of types of flexible materials. It is particularly well suited to dispensing flexible ducting 40 which is compressible both transversely and longitudinally. For purposes of understanding its typical basic structure, it will be understood that it consists of tubular insulating material 41 having an inner liner 42 and an outer liner 43. Enclosed in the flexible ducting to give it shape is a helical spring wire, not shown, which forms a helical rib 44 about the flexible ducting. The flexible ducting can be manufactured in any length and diameter. It is the practice in the industry to manufacture the ducting in standard lengths and diameters and to package the ducting in a longitudinally compressed condition.
As shown in FIGS. 1, 2 and 3, the flexible ducting 40 is disposed in the container 10 in a U-shaped configuration, longitudinally compressed so as to fit the maximum length of the ducting in the container and with an end portion 45 in the dispensing position 24. The distance across the dispensing opening 37 between the first end flap 31 and the remainder of the lower and upper cover flaps 33 and 34 at the perforations 35 is less than the diameter of the flexible ducting.
SECOND FORM
The second form of the container of the present invention is generally indicated by the numeral 110 and is shown in FIGS. 5 through 9. As previously noted, the container of the present invention is adaptable to a wide variety of specific embodiments. The second form of the container is an embodiment adapted for use in dispensing a twenty-five foot length of flexible ducting longitudinally compressed to fit within the container.
The container 110 has a housing or carton 111 having side walls 112, a front wall 113 and a back wall 114. The carton has a lower end wall 115, an opposite upper end wall 116 and a hand opening 117. The carton 111, of course, can be fitted with a securing means such as that of the carton 11 for the purposes described but this is not shown in the drawings. The front wall and back wall have openings or slots 118 therein in predetermined corresponding positions adjacent to the upper end wall 116. The carton encloses an internal chamber 123 which has a dispensing position 124 just inwardly of the upper end wall 116.
The container 110 has a control means or mechanism 130 which is incorporated in the upper end wall 116 of the carton 111. Thus, the upper end wall is composed of a first end flap 131 borne by and integral with the side wall 112 on the left as viewed in FIG. 7. A second end flap 132 is borne by and integral with the side wall 112 on the right as viewed in FIG. 7. A front flap 133 is mounted on the front wall 113 of the carton 111 and a rear flap 134 is mounted on the back wall 114. Both the front and rear flaps are dimensioned to overlay the dispensing position 124, as shown in FIG. 6, in flattened condition when the carton is sealed. The front and rear flaps 133 and 134 have fold or score lines 135 which permit the front and rear flaps to be folded into the configurations shown in FIGS. 8 and 9. The front and rear flaps each are severed as shown in FIG. 6 so that when each is folded along the score lines 135, projections 136 are formed which are engageable in the slots 118 of their respective front and back walls 113 and 114 releasably to retain the front and rear flaps in the configurations shown in FIG. 8.
When the front flap 133 and rear flap 134 are disposed in the configurations shown in FIG. 8, they define a dispensing opening 137 therebetween. Both the front and rear flaps are, in the folded configurations, substantially triangular in cross section having shoulders 138 bounding and defining the dispensing opening and oblique surfaces 139 facing substantially inwardly of the internal chamber 123.
The container 110 is adapted to house for transport and storage a length of flexible ducting 140. The flexible ducting is constructed of tubular insulating material 141 having an inner liner 142 and an outer liner 143. An internal helical spring wire, not shown, imparts a helical rib 144 to the flexible ducting. The flexible ducting has an end portion 145, visible in phantom lines in FIG. 6, which when the flexible ducting is sealed within the carton 111 is in the dispensing position 124 engaging the front and rear flaps 133 and 134 as they compose part of the upper end wall 116. As previously noted, in the sealed configuration the flexible ducting 140 is of a fifty foot length when not compressed longitudinally thereof. However, when sealed within the carton 111, the flexible ducting is compressed to a substantial degree along its longitudinal axis and is held in this condition by the sealed lower and upper end walls 115 and 116 respectively which are individually engaged by the opposite ends of the flexible ducting. The flexible ducting is thus held in position in a straight configuration rather than the U-shaped configuration in the case of the container 10 shown in FIG. 2.
OPERATION
The operation of the described embodiments of the present invention is believed to be readily apparent and is briefly summarized at this point. The containers 10 and 110 are operated in similar manners. In both instances the flexible ducting 40 and 140 is longitudinally compressed during packaging so that the ducting is retained in the compressed condition by engagement with the upper end wall 16 and 116, respectively. In the case of the flexible ducting 40, the ducting is placed under such compression in the U-shaped configuration shown in FIG. 2 so that both ends engage the upper end wall 16. In the case of container 110, the flexible ducting is captured in the compressed condition between the lower end wall 115 and the upper end wall 116. In both cases, the upper end wall is sealed and the containers are transported and stored in this condition. Container 10 is shown in a sectional view in this sealed condition in FIG. 2. Container 110 is shown in a perspective view in this sealed condition in FIG. 5.
When it becomes time to dispense flexible ducting from the containers 10 and 110, the upper end walls 16 and 116, respectively, are opened as hereinafter described. In the case of container 10, the dispensing flaps 36 are torn along their respective perforations 35 and opened outwardly and the first end flap 31 is slipped from beneath the remainder of the lower and upper cover flaps 33 and 34 respectively. This condition is shown in FIG. 3. With respect to the container 110, the first and second end flaps 131 and 132 respectively are opened outwardly to expose the front flap 133 and the rear flap 134 as shown in FIG. 6. The front and rear flaps are then folded along the fold lines 135 and the projections 136 individually inserted and captured in the slots 118 of the front and back walls 113 and 114 respectively. The front and rear flaps are thus retained in the configuration shown in FIG. 8.
Prior to dispensing the flexible ducting 40 from the container 10, the operator can secure the carton 11 on a suitable stationary object such as the bar 22 at the construction site using the securing means 18.
The operator thereafter simply grasps the end portion 45 or 145 of the flexible ducting 40 or 140 and pulls it through the dispensing opening 37 or 137 until the desired length of flexible ducting has been pulled from the carton 11 or 111. The operator then severs the desired length of flexible ducting using a knife, shears or the like. The transverse compression of the flexible ducting by the control mechanism 30 or 130 prevents more than the desired length of flexible ducting from being paid out, permits the ducting pulled from the carton to be stretched to its full length for accuracy in cutting and retains the longitudinally compressed remainder of the flexible ducting within the carton. The operator can simply leave the newly formed end portion in the opening or push it back into the dispensing position 24 or 124 within the internal chamber 23 or 123. When the operator is ready for a new length of flexible ducting, he simply repeats the process.
The action of the control mechanisms 30 and 130 is such that the transverse compression imparted to the flexible ducting is sufficient to hold the ducting in position unless pulled outwardly or pushed inwardly by the operator. The compression is not so great as to cause any damage whatsoever to the ducting.
In the preferred forms of the invention the resistance is provided by transverse compression of the ducting as noted. This is achieved in both preferred forms of the invention by the opening 37 and 137 being smaller in at least one dimension than the diameter of the flexible ducting. However, the invention also includes the application of such resistance by other suitable means as may be appropriate and permitted by the extent of the longitudinal compression of the flexible ducting. For example, various means for imparting frictional resistance at the dispensing openings 37 and 137 may also be employed.
If the operator finishes with the installation of flexible ducting at the job site before using all of the ducting within the container 10 or 110, he simply pushes the newly formed end portion back into the internal chamber 23 or 123. In the case of container 10, the dispensing flaps 36 are then folded over the dispensing opening and the first end flap 31 folded over the dispensing flaps and slipped under the lower and upper cover flaps 33 and 34 respectively, as shown in FIG. 4. The container is thus sealed and can be transported and stored for subsequent use without further effort.
As to the container 110, the projections 136 are disengaged from the slots 118 and the front and rear flaps unfolded and placed in flattened condition over the end portion 145 of the flexible ducting. The first and second end flaps 131 and 132 are then folded into covering relation as shown in FIG. 5 and tape, staples or the like employed to hold them in place. The container 110 can subsequently be transported and stored as desired.
Therefore, the container for dispensing flexible material of the present invention has particular utility in the dispensing of flexible ducting and permits the user to dispense from the container only the length of flexible ducting desired while retaining the remainder thereof within the housing for subsequent use; preserves the unused portion of the ducting in a protected condition at the job site insulated from damage due to puncture, tearing or the like or due to dust, paint or other construction materials; and insures that waste due to abandonment of unused ducting at the job site is reduced to a minimum.
Although the invention has been herein shown and described in what are conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention which is not to be limited to the illustrative details disclosed. | A container for dispensing flexible material having a housing adapted to receive the flexible material with an end portion in a dispensing position; and a control mechanism borne by the housing overlaying the dispensing position for resisting movement of the flexible material therethrough while permitting the flexible material to be pulled from the housing therethrough by the end portion for dispensing in selected lengths. |
CROSS REFERENCE TO RELATED APPLICATION
This application claims priority to International Application No. PCT/IB03/00495 published in the German language on Feb. 07, 2003, which claims the benefit of priority to European Patent Office (EPO) Application No. 02075906.4, which was filed on Mar. 7, 2002.
BACKGROUND OF THE INVENTION
The invention relates to a circuit arrangement for operating a high pressure discharge lamp equipped with
input terminals for connection to the poles of a supply voltage source a DC-DC-converter coupled to the input terminals and comprising
an inductive element L 1 , a unidirectional element D 1 , a switching element S 1 , output terminals, a first control circuit coupled to a control electrode of the switching element S 1 for generating a control signal for rendering the switching element S 1 alternately conductive and non-conductive, a second control circuit, coupled with the first control circuit for controlling the level of an output voltage of the DC-DC converter that is present between the output terminals,
a DC-AC-converter coupled to the output terminals and equipped with lamp connection terminals for generating an AC lamp voltage out of the output voltage.
Such a circuit arrangement is known from DE 10025610 A1. During the starting phase (the phase between ignition and run-up) of the high pressure discharge lamp (further also indicated as lamp), the discharge in the high pressure discharge lamp has not yet become stable. To keep the discharge alive, a comparatively high output voltage is needed. This comparatively high output voltage, however, leads to a relatively high power dissipation in the circuit arrangement after the starting phase, when the high pressure discharge lamp is in stationary operation.
The invention aims to provide a circuit arrangement for operating a high pressure discharge lamp that effectively stabilizes the discharge during the starting phase and has a comparatively low power dissipation during stationary lamp operation.
OBJECTS AND SUMMARY OF THE INVENTION
A circuit arrangement as mentioned in the opening paragraph is therefor in accordance with the invention characterized in that the second control circuit is further equipped with a state control circuit for changing the level at which the output voltage is controlled from a first level associated with the starting of the high pressure discharge lamp to a second level associated with the stationary operation of the high pressure discharge lamp.
More in particular by choosing the first level higher than the second level, a high output voltage, necessary to stabilize the discharge, is present during the starting phase. A lower output voltage, however, is present when the high pressure discharge lamp is in stationary operation so that power dissipation in the circuit arrangement is limited.
It has been found that a dependable and correct functioning of the state control circuit can be realized; in case the circuit arrangement is equipped with means for generating a power signal that represents the power supplied to the high pressure discharge lamp and for activating the state control circuit after the power signal has increased above a predetermined reference value. To account for minor differences in the behavior of individual lamps and to make sure that the output voltage is only lowered when the lamp plasma has actually become stable, it has been found advantageous to further equip the circuit arrangement with a delay circuit coupled to the state control circuit for timing a predetermined delay time interval after the power signal has increased above the predetermined reference value and for activating the state control circuit after said predetermined delay time interval has timed out.
When the circuit arrangement is operating in the stationary state, the amount of power dissipated in the components of the circuit arrangement decreases, when the second level is decreased. However, a decrease in the second level also causes the reignition of the lamp to take longer. This slow reignition has been found to cause a rapid decrease in lamp performance. For this reason it is advantageous to equip the second control circuit with a third control circuit coupled to the lamp connection terminals for controlling the second level in dependency of the width of a reignition voltage peak present between the lamp terminals when the DC-AC-converter changes the polarity of the lamp voltage. The third control circuit makes sure that the power dissipation during stationary operation is relatively low while reignition of the lamp is taking place relatively fast so that a rapid decrease in lamp performance is avoided.
Good results have been obtained with a circuit arrangement according to the invention, wherein the DC-AC-converter is a bridge circuit comprising at least two bridge switching elements and a bridge control circuit coupled with control electrodes of the bridge switching elements.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of a circuit arrangement according to the invention will be explained making reference to a drawing. In the drawing
FIG. 1 shows an embodiment of a circuit arrangement according to the invention with a high pressure discharge lamp connected to it.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 , K 1 and K 2 are input terminals for connection to the poles of a supply voltage source. In put terminals K 1 and K 2 are connected by means of a series arrangement of inductor L 1 and switching element S 1 . The inductor L 1 forms an inductive element L 1 . A common terminal of inductor L 1 and switching element S 1 is connected to an anode of diode D 1 . Diode D 1 forms a unidirectional element D 1 . Terminal K 3 is connected to a cathode of diode D 1 . Terminal K 4 is connected to input terminal K 2 via ohmic resistor R. A control electrode of switching element S 1 is connected to an output terminal of circuit part 1 . Circuit part I is a first control circuit for generating a control signal for rendering the switching element Si alternately conductive and non-conductive. An input terminal of circuit part I is connected to an output terminal of circuit part II. Circuit part II is a second control circuit for controlling the level of an output voltage that is present between the output terminals. An output terminal of circuit part II is connected to an input terminal of circuit part I. Circuit part II comprises a circuit part Scc and a circuit part III. Circuit part Scc is a state control circuit for changing the level at which the output voltage is controlled from a first level associated with the starting of the high pressure discharge lamp to a second level associated with the stationary operation of the high pressure discharge lamp. Circuit part III forms a third control circuit for controlling the second level of the output voltage in dependency of the width of a re-ignition voltage peak present between the lamp terminals when the DC-AC-convener changes the polarity of the lamp voltage. An input terminal of circuit part II is connected to the cathode of diode D 1 . Circuit parts I and II, inductor L 1 , switching element S 1 , diode D 1 and terminals K 3 and K 4 together form a DC-DC-converter of the type up or boost converter. K 3 and K 4 form the output terminals of the DC-DC-converter. Terminals K 3 and K 4 are connected by means of a series arrangement of switching elements S 2 and S 3 and by means of a series arrangement of capacitors Cl and C 2 . Switching element S 2 is shunted by diode D 2 and switching element S 3 is shunted by diode D 3 . Respective control electrodes of switching elements S 2 and S 3 are connected to respective output terminals of a circuit part CC for generating control signals to render switching elements S 2 and S 3 alternately conductive and non-conductive. A common terminal of switching elements S 2 and S 3 is connected to a common terminal of capacitors Cl and C 2 by means of a series arrangement of an inductor L 2 , terminal K 5 , high pressure discharge lamp LA and terminal K 6 . Terminals K 5 and K 6 are terminals for lamp connection and are connected by a capacitor C 3 that shunts the high pressure discharge lamp LA. Circuit part CC. switching elements S 2 and S 3 , capacitors C 1 , C 2 and C 3 . inductor L 2 and lamp connection terminals K 5 and K 6 together form a DC-AC-converter for generating an AC lamp current out of the output voltage. This DC-AC-converter is a bridge circuit Input terminal K 2 is connected to a first input terminal of circuit part PSG. A second input terminal of circuit part PSG is connected to terminal K 3 . Ohmic resistor R and circuit part PSG together form means for generating a power signal that represents the power supplied to the high pressure discharge lamp and for activating the state control circuit SCC. Art output terminal of circuit part PSG is connected with an input terminal of circuit part DT. Circuit pan DT is a delay circuit for timing a predetermined delay time interval after the power signal has increased above the predetermined reference value and for activating the state control circuit Scc after said predetermined delay dine interval has timed out. An output terminal of circuit part DT is connected to an input terminal of state control circuit Scc. Circuit part III is coupled to lamp connection terminals K 5 and K 6 . In FIG. 1 this coupling is represented by means of a dotted line.
The operation of the circuit arrangement shown in FIG. 1 is as follows.
When the input terminals K 1 and K 2 are connected to the poles of a (DC) supply voltage source, a DC supply voltage is present between the input terminals K 1 and K 2 . Circuit part I generates a control signal that renders switching element S 1 alternately conductive and non-conductive. As a result the DC supply voltage is converted by the DC-DC-converter into an output voltage that is a DC-voltage with an amplitude that is higher than the amplitude of the DC supply voltage. This output voltage is present between the terminals K 3 and K 4 and (immediately after ignition) is controlled at a first level that is relatively high by the circuit part II. The circuit part CC generates control signals that alternately render switching elements S 2 and S 3 conductive and non-conductive. More in particular the switches S 2 and S 3 are controlled in a way that is known in the art as the half bridge commutating forward mode. In the first half a period of this mode the first switch is non-conductive, while the second switch is rendered alternately conductive and non-conductive at a high frequency. In the second half period of this mode the first switch is rendered alternately conductive and non-conductive at a high frequency, while the second switch is non-conductive. As a result the current through the lamp is a low frequency substantially square wave shaped AC current. In a first approximation the power consumed by the lamp is equal to the power consumed by the DC-AC-converter. This latter power is the product of the current consumed by the DC-AC-converter multiplied by the voltage present between terminals K 3 and K 4 . Circuit part PSG generates a power signal that represents this power, by multiplying the voltage over ohmic resistor R (representing the current consumed by the DC-AC-converter) with the amplitude of the voltage between terminals K 3 and K 4 . The power signal is compared with a predetermined reference value by means of a comparator comprised in circuit part PSG. Immediately after the high pressure discharge lamp has been ignited in a way that is well known in the art the discharge in the lamp is not yet stable and the power consumed by the lamp is relatively low. As a consequence the power signal is lower than the predetermined reference value and the output of the comparator that is connected to the output of circuit part PSG is low. After some time the plasma in the high pressure discharge lamp LA stabilizes and the amount of power consumed by the lamp increases. The power signal increases as well and when the power signal has increased above the predetermined reference value, the voltage at the output terminal of circuit part PSG changes from low to high. This change activates a timer that is comprised in circuit part DT. The timer times out a predetermined delay time interval. When this predetermined delay time interval has been timed out, the output terminal of circuit part DT changes from low to high and the state control circuit Scc is activated. The state control circuit Scc changes the level at which the output voltage is controlled from a first level associated with the starting of the high pressure discharge lamp to a second level of associated with the stationary operation of the high pressure discharge lamp. This second level is lower than the first level. As a result the power dissipation in the DC-AC-converter is decreased. During stationary operation the circuit part III monitors the width of the re-ignition voltage peak that is present between the lamp terminals when the DC-AC-converter changes the polarity of the lamp voltage. Circuit part III comprises a comparator coupled to a timer. The comparator compares the voltage over the lamp with a reference value. The reference value is chosen between the lamp voltage when the lamp is conducting the lamp current and the highest value of the lamp voltage during re-ignition. When the voltage over the lamp is higher than the reference value, the comparator activates the timer and when the voltage over the lamp is lower than the reference value the comparator stops the timer. The timer thus times the time interval during which the voltage over the lamp is higher than the reference value. This measured time interval is compared with a reference by means of a further comparator. When the measured time interval is higher than the reference, this means that the re-ignition is too slow and the circuit part II increases the level at which the output voltage present between terminals K 3 and K 4 is controlled. When the measured time interval is lower than the reference, this means that the re-ignition is taking place faster than necessary to prevent a rapid decrease in lamp performance while the power dissipation in the circuit arrangement is relatively high. To lower this power dissipation the circuit part II decreases the level at which the output voltage is controlled. Thus the circuit part II realizes that the level of the output voltage is controlled such that power dissipation is relatively low while the re-ignition of the lamp is taking place fast enough to prevent a rapid decrease in lamp performance. | In a ballast circuit for supplying a high pressure discharge lamp and comprising an up-converter and a bridge circuit, the output voltage of the up-converter is controlled at a higher level immediately after the ignition of the lamp and at a lower level during stationary operation. Stabilization of the discharge immediately after ignition of the lamp and a relatively small power dissipation are both realized in this ballast circuit. |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/667,523 filed Apr. 1, 2005, which is incorporated by reference as if fully set forth.
FIELD OF INVENTION
[0002] The present invention relates to a wireless communication system including a plurality of multi-band access points (APs) and a multi-band wireless transmit/receive unit (WTRU), (i.e., a mobile station). More particularly, the present invention is related to a method and apparatus for selecting a particular one of the multi-band APs to associate with based on frequency band information transmitted from the multi-band APs to the multi-band WTRU.
BACKGROUND
[0003] A typical wireless local area network (WLAN) includes an AP which provides radio access to WTRUs in a coverage area of the AP. The AP is comprised by a basic service set (BSS) which is a basic building block of an IEEE 802.11-based WLAN. Multiple BSSs may be interconnected through a distribution system (DS) to form an extended service set (ESS).
[0004] The WLAN may be configured in an infrastructure mode or an Ad-hoc mode. In the infrastructure mode, wireless communications are controlled by an AP. The AP periodically broadcasts beacon frames to enable WTRUs to identify, and communicate with, the AP. In the Ad-hoc mode, a plurality of WTRUs operate in a peer-to-peer communication mode. The WTRUs establish communication among themselves without the need of coordinating with a network element. However, an AP may be configured to act as a bridge or router to another network, such as the Internet.
[0005] The WTRUs and the AP may be configured to utilize multiple frequency bands for communication. In a conventional wireless communication system, a multi-band WTRU transmits multiple probe requests on different channels of a frequency band to discover if there are any APs available in the area. Once an AP receives the probe request, it sends a probe response packet to the WTRU. The AP will send the probe response packet on its operating channel in a particular frequency band. The probe response packet contains required parameters, such as supported rate, or the like, for the WTRU to associate with the AP. The WTRU will send an association request packet and waits for an association response packet from an AP for further data communication.
[0006] Once associated, the multi-band WTRU may scan other frequency bands in search of a better communication band by transmitting a probe request packet and waiting for a probe response packet. Upon receiving another probe response packet, the WTRU compares the frequency bands and/or the AP and selects a more preferable frequency band and/or AP.
[0007] In the conventional wireless communication system, the multi-band WTRU must scan and compare different frequency bands to determine the frequency band that provides the best quality of wireless communications. However, these scanning and comparison functions are time-consuming and require a significant amount of battery power. A method and apparatus for reducing the amount of time and battery power required to make frequency band and channel selection decisions is desired.
SUMMARY
[0008] The present invention is related to a method and apparatus for selecting one of a plurality of multi-band APs to associate with a multi-band WTRU. The multi-band APs broadcast frequency band information regarding multiple frequency bands on which the multi-band AP is configured to operate. The multi-band WTRU selects a particular multi-band AP to associate with and a frequency band to use to communicate with the selected multi-band AP based on the frequency band information. If the multi-band WTRU receives frequency band information from the selected multi-band AP which indicates that a characteristic, (e.g., throughput, path loss, load, capacity, backhaul), of the selected frequency band is unacceptable, the multi-band WTRU determines whether to disassociate with the selected multi-band AP or to continue to associate with the selected multi-band AP via a different frequency band.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] A more detailed understanding of the invention may be had from the following description, given by way of example and to be understood in conjunction with the accompanying drawings wherein:
[0010] FIG. 1 shows a wireless communication system including a plurality of multi-band APs and a multi-band WTRU which operate in accordance with the present invention;
[0011] FIG. 2 is an exemplary beacon frame which comprises frequency band information transmitted from the multi-band APs to the multi-band WTRU of the wireless communication system of FIG. 1 ;
[0012] FIG. 3 is a flow diagram of a process for the multi-band WTRU to select one of the multi-band APs to associate with in accordance with the present invention;
[0013] FIG. 4 is a flow diagram of a process for the multi-band WTRU to determine whether to change a particular frequency band used for wireless communications with a multi-band AP or to associate with a different multi-band AP in accordance with the present invention; and
[0014] FIG. 5 is a flow diagram of a process for establishing a wireless communication link between the multi-band WTRU and a preferable multi-band AP over a preferable frequency band in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Hereafter, the terminology “WTRU” includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. Such WTRUs include, but are not limited to, phones, video phones, and Internet ready phones, personal data assistances (PDAs) and notebook computers with wireless modems that have network capabilities.
[0016] When referred to hereafter, the terminology “AP” includes but is not limited to a Node-B, a base station, a site controller or any other type of interfacing device in a wireless environment that provides other WTRUs with wireless access to a network with which the AP is associated.
[0017] The features and elements of the present invention may be implemented on a single IC, (such as an application specific integrated circuit (ASIC)), multiple ICs, discrete components or a combination of discrete components and ICs.
[0018] The present invention is applicable to any type of wireless communication systems including, but not limited to, 802.x-based wireless communication systems.
[0019] FIG. 1 shows a wireless communication system 100 including a plurality of multi-band APs 105 1 - 105 N and a multi-band WTRU 110 which operate in accordance with the present invention. Each of the multi-band APs 105 1 - 105 N and the multi-band WTRU 110 operate on at least two frequency bands. The multi-band APs 105 1 - 105 N transmit frequency band information 115 1 - 115 N which indicates the different multi-bands that the respective APs 105 1 - 105 N are configured to operate on. Each of the multi-band APs 105 1 - 105 N include a respective transceiver 120 1 - 120 N and a respective processor 125 1 - 125 N . Each respective transceiver 120 1 - 120 N is configured to operate on at least two different frequency bands. Each respective processor 125 1 - 125 N generates and formats the respective frequency band information 115 1 - 115 N and provides it to the transceiver 120 1 - 120 N for transmission. The multi-band WTRU 110 also includes a transceiver 130 and a processor 135 . The transceiver 130 is configured to operate on at least two different frequency bands. The processor 135 processes the frequency band information 115 1 - 115 N received by the transceiver 130 from the multi-band APs 105 1 - 105 N , selects a multi-band AP 105 to associate with, and a frequency band to use in communication with the selected multi-band AP 105 , based on the frequency band information 115 1 - 115 N .
[0020] The multi-band WTRU 110 and the multi-band APs 105 1 - 105 N may use any management, control or data packet to provide the frequency band information to the multi-band WTRU 110 . For example, an authentication frame, (which is a management frame), can also be used to send multi-band frequency information. Similarly, this packet can be piggybacked on any of the current or future WLAN packets.
[0021] Alternatively, a proprietary message exchange between the multi-band WTRU 110 and the multi-band APs 105 1 - 105 N may also be utilized to provide the frequency band information to the multi-band WTRU 110 .
[0022] FIG. 2 shows an exemplary beacon frame which comprises frequency band information 115 transmitted from each of the multi-band APs 105 1 - 105 N to the multi-band WTRU 110 of the wireless communication system 100 of FIG. 1 . The frequency band information 115 indicates whether a particular multi-band AP 105 supports multiple frequency bands 205 1 - 205 N , channel numbers 215 and timing information 220 or the like.
[0023] The frequency band information 115 may further include quality metric information 210 1 - 210 N for each of the frequency bands 205 1 - 205 N . The quality metric information may include, but is not limited to, path loss, load, (e.g., the number of associated WTRUs 110 ), throughput, capacity and backhaul on each frequency band.
[0024] FIG. 3 is a flow diagram of a process 300 for establishing a wireless communication link between a particular one of 115 1 - 115 N and the multi-band WTRU 110 in the wireless communication system 100 of FIG. 1 based on frequency band information 115 1 - 115 N transmitted from the multi-band APs 105 1 - 105 N to the multi-band WTRU 110 . In step 305 , a plurality of multi-band APs 105 1 - 105 N broadcast frequency band information 115 1 - 115 N regarding multiple frequency bands on which the respective multi-band AP s 105 1 - 105 N are configured to operate. The frequency band information 115 1 - 115 N may be broadcast in a beacon frame, as shown in FIG. 2 . In step 310 , a multi-band WTRU 110 receives and processes the frequency band information 115 1 - 115 N . In step 315 , the multi-band WTRU 110 selects a particular one of the multi-band APs 105 1 - 105 N to associate with, and a frequency band to use to communicate with the selected multi-band AP 105 based on the frequency band information 115 1 - 115 N .
[0025] FIG. 4 is a flow diagram of a process 400 for the multi-band WTRU 110 to determine whether to change a particular frequency band used for wireless communications with a multi-band AP 105 , or to associate with a different multi-band AP 105 in accordance with the present invention. In step 405 , the multi-band WTRU 110 associates with a particular multi-band AP 105 on a particular frequency band. In step 410 , the multi-band WTRU 110 receives frequency band information 115 from the particular multi-band AP 105 including a quality metric which indicates that the particular frequency band has, for example, poor throughput. In step 415 , the multi-band WTRU 110 either disassociates with that the multi-band AP 105 and associates with another multi-band AP 105 continues to associate with the same multi-band AP 105 over a different frequency band for which the frequency band information 115 includes a quality metric which indicates a good, (i.e., high), throughput.
[0026] FIG. 5 is a flow diagram of a process 500 for establishing a wireless communication link between the multi-band WTRU and a preferable multi-band AP over a preferable frequency band in accordance with the present invention. In step 505 , a multi-band WTRU 110 broadcasts an association request packet or a probe request packet which is received by a plurality of multi-band APs 105 1 - 105 N . The multi-band WTRU 110 may include an indication of the multi-band capability and related information of the WTRU 110 in the request packet. In step 510 , each of the multi-band APs 105 1 - 105 N sends an association response packet or a probe response packet to the multi-band WTRU 110 which includes frequency band information 115 1 - 115 N in accordance with the multi-band capability of the WTRU 110 . In step 515 , the multi-band WTRU 110 selects a preferable frequency band and a preferable multi-band AP 105 to associate with based on the frequency band information 115 1 - 115 N .
[0027] In another embodiment, the wireless communication system 100 may also include a single-band AP and a single-band WTRU, in addition to the multi-band APs 105 1 - 105 N and the multi-band WTRU 104 a . If a single-band WTRU is associated with a multi-band AP 105 , the information regarding the multiple frequency bands of the multi-band AP 105 other than information regarding the frequency band on which the single-band WTRU is configured to operate will be simply ignored by the single-band WTRU since the single-band WTRU not configured to communicate on multiple frequency bands. The single-band AP broadcasts its information regarding its single frequency band, (such as timing, load, or the like) in a beacon frame. Both a single-band WTRU and a multi-band WTRU 110 may utilize this information to decide whether or not to associate with the single-band AP.
[0028] In accordance with the present invention, the multi-band WTRU 110 is not required to consume significant time and battery power for scanning various frequency bands in search of an adequate AP to associate with. Moreover, by providing the multi-band WTRU 110 with quality metrics of each frequency band, (such as throughput), the WTRU is enabled to optimize not only its own throughput, but also the throughput of the AP 105 .
[0029] Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. | A method and apparatus for selecting one of a plurality of multi-band access points (APs) to associate with a multi-band wireless transmit/receive unit (WTRU) are disclosed. The multi-band APs broadcast frequency band information regarding multiple frequency bands on which the multi-band AP is configured to operate. The multi-band WTRU selects a particular multi-band AP to associate with and a frequency band to use to communicate with the selected multi-band AP based on the frequency band information. If the multi-band WTRU receives frequency band information from the selected multi-band AP which indicates that a characteristic, (e.g., throughput, path loss, load, capacity, backhaul), of the selected frequency band is unacceptable, the multi-band WTRU determines whether to disassociate with the selected multi-band AP or to continue to associate with the selected multi-band AP via a different frequency band. |
This application claims the benefit of U.S. provisional application Ser. No. 60/021,631 filed Jul. 12, 1996.
BACKGROUND OF THE INVENTION
The present invention relates to a process for the preparation of chiral beta-amino acids of the formula ##STR1## wherein R is selected from the group consisting of alkenyl, alkynyl, lower alkyl, aryl, substituted aryl, pyridyl, and furanyl and R 1 is lower alkyl; which process comprises treating an aldehyde of the formula ##STR2## with (R) or (S) phenylglycinol in tetrahydrofuran (THF) or toluene to produce an imino alcohol of the formula ##STR3## reacting said imino alcohol with BrZnCH 2 CO 2 -tBu in N-methyl pyrrolidinone (NMP), dimethylsulfoxide (DMSO) or THF followed by addition of aqueous ammonium chloride and hydrochloric acid to produce an amino alcohol of the formula ##STR4## reacting the amino alcohol with sodium periodate (NaIO 4 ) or lead tetraacetate (Pb(OAc) 4 ) to form an imine of the formula ##STR5## hydrolyzing said imine in the presence of para toluene sulfonic acid to produce an (R) or (S) beta-amino acid of the formula ##STR6##
More preferably, the present invention relates to a process for the preparation of the chiral beta-amino acid of the formula ##STR7## known by the chemical name ethyl 3S-amino-4-pentynoate and salts thereof. The process comprises treating 3-(trimethylsilyl)-2-propynal with L-phenylglycinol in toluene, to produce αS- 3-(trimethylsilyl)-2-propynylidene!amino!benzenethanol; reacting αS- 3-(trimethylsilyl)-2-propynylidene!amino!benzenethanol with BrZnCH 2 CO 2 t-Bu in THF/NMP to produce 1,1-dimethylethyl 3S- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate; reacting the 1,1-dimethylethyl 3S- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate with sodium periodate to form 1,1-dimethylethyl 3S- (phenylmethylene)amino!-5-(trimethylsilyl)-4-pentynoate; hydrolyzing 1,1-dimethylethyl 3S- (phenylmethylene)amino!-5-(trimethylsilyl)-4-pentynoate to produce 1,1-dimethylethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate; and transesterifying 1,1-dimethylethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate and desilylating to produce ethyl 3S-amino-4-pentynoate.
The preferred chiral β-amino acid produced by the process of the present invention is useful in preparing ethyl 3S- 4- 4-(aminoiminomethyl)phenyl!amino!-1,4-dioxobutyl!amino!-4-pentynoate a pharmaceutical agent useful as a platelet aggregation inhibitor. Said pharmaceutical agent is more fully described in U.S. Pat. No. 5,344,957.
A preparation of ethyl 3S-amino-4-pentynoate is described in Method 3 of Scheme V of U.S. Pat. No. 5,344,957. Additional methods for preparing ethyl 3S-amino-4-pentynoate are disclosed by D. H. Hua and A. Verma, Tetrahedron Lett., 547-550 (1985) and by T. Kametani, Heterocycles, Vol. 17, 463 (1982).
U.S. Pat. No. 5,536,869 discloses a process for preparing ethyl 3S-amino-4-pentynoate monohydrochloride which comprises:
(a) treating (trimethylsilyl)acetylene sequentially with n-butyllithium and 4-formylmorpholine in the presence of an aprotic solvent followed by acid hydrolysis to give 3-(trimethylsilyl)-2-propynal;
(b) treating 3-(trimethylsilyl)-2-propynal, the product of step a, with lithium bis(trimethylsilyl)amide in the presence of an aprotic solvent to give N,3-bis(trimethylsilyl)-2-propyn-1-imine in situ, treating N,3-bis(trimethylsilyl)-2-propyn-1-imine with lithium t-butyl acetate followed by hydrolytic cleavage to give (±)1,1-dimethylethyl 3-amino-5-(trimethylsilyl)-4-pentynoate;
(c) treating (±)1,1-dimethylethyl 3-amino-5-(trimethylsilyl)-4-pentynoate, the product of step b, with p-toluenesulfonic acid in the presence of aprotic solvents to give (±)1,1-dimethylethyl 3-amino-5-(trimethylsilyl)-4-pentynoate, mono p-toluenesulfonic acid salt, treating the resulting salt with ethanol in the presence of p-toluenesulfonic acid, followed by neutralization to give (±)ethyl 3-amino-5-(trimethylsilyl)-4-pentynoate; and
(d) treating (±)ethyl 3-amino-5-(trimethylsilyl)-4-pentynoate, the product of step c, with a catalytic amount of base in the presence of alkanol solvent followed by a catalytic amount of acid to give the desilylated (±)ethyl 3-amino-4-pentynoate in situ, treating (±)ethyl 3-amino-4-pentynoate with (R)-(-)-mandelic acid in the presence of aprotic solvents to give ethyl 3S-amino-4-pentynoate compounded with αR-hydroxybenzeneacetic acid; and
(e) treating ethyl 3S-amino-4-pentynoate compounded with αR-hydroxybenzeneacetic acid, the product of step d, with gaseous hydrochloric acid in the presence of an aprotic solvent to give ethyl 3S-amino-4-pentynoate, monohydrochloride; with the understanding that when a pharmaceutically acceptable acid addition salt other than hydrochloride is desired the ethyl 3S-amino-4-pentynoate compounded with αR-hydroxybenzene acetic acid, the product of step d, is treated with the appropriate acid corresponding to the desired salt.
It would be desirable to provide a process for the preparation of said amino acids and preferably of ethyl 3S-amino-4-pentynoate which is amenable to scale-up, and which employs raw materials which are readily available, resulting in high yield and a high level of optical purity which doesn't require any chromatography and/or separation of diastereoisomers.
SUMMARY OF THE INVENTION
The present invention relates to a process for the preparation of chiral beta-amino acids of the formula ##STR8## wherein R is selected from the group consisting of alkenyl, alkynyl, aryl, lower alkyl, substituted aryl, pyridyl and furanyl and R 1 is lower alkyl; which process comprises treating an aldehyde of the formula ##STR9## with (R) or (S) phenylglycinol in tetrahydrofuran (THF) or toluene to produce an imino alcohol of the formula ##STR10## reacting said imino alcohol with BrZnCH 2 CO 2 -tBu in N-methyl pyrrolidinone (NMP), dimethylsulfoxide (DMSO) or THF followed by addition of ammonium chloride to produce an amino alcohol of the formula ##STR11## reacting the amino alcohol with sodium periodate (NaIO 4 ) or lead tetraacetate (Pd(OAc) 4 ) to form an imine of the formula ##STR12## hydrolyzing said imine in the presence of para toluene sulfonic acid to produce an R or S amino acid of the formula ##STR13##
More preferably, the invention herein is directed to a process for the preparation of ethyl 3S-amino-4-pentynoate. The process involves treating 3-(trimethylsilyl)-2-propynal with L-phenylglycinol in toluene to produce αS- 3-(trimethylsilyl)-2-propynylidene amino!benzenethanol; reacting αS- 3-(trimethylsilyl)-2-propynylidene!amino!benzenethanol with BrZnCH 2 CO 2 t-Bu in THF/NMP to produce 1,1-dimethylethyl 3S- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate; reacting the 1,1-dimethylethyl 3S- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate with sodium periodate to form 1,1-dimethylethyl 3S- (phenylmethylene)amino!-5-(trimethylsilyl)-4-pentynoate; hydrolyzing 1,1-dimethylethyl 3S- (phenylmethylene)amino!-5-(trimethylsilyl)-4-pentynoate to produce 1,1-dimethylethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate; and transesterifying 1,1-dimethylethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate and desilylating to produce ethyl 3S-amino-4-pentynoate.
DETAILED DESCRIPTION OF THE INVENTION
The invention herein is directed to the preparation of beta-amino acids of the formula ##STR14## and acid addition salts thereof wherein R is selected from the group consisting of alkenyl, alkynyl, lower alkyl, aryl, substituted aryl, pyridyl, and furanyl and R 1 is lower alkyl.
More specifically, the invention herein is directed to the preparation of ethyl 3S-amino-4-pentynoate of the formula ##STR15## and addition salts thereof.
A synthetic scheme for the most preferred synthetic method is outlined in Scheme I and the following description thereof. ##STR16##
Aldehyde A is prepared according to methodology disclosed in U.S. Pat. No. 5,536,869.
In Scheme I aldehyde A is transformed to imine B by reaction with L-phenylglycinol in toluene (or alternatively in THF) followed by drying with MgSO 4 , or molecular sieve or azeotropic distillation.
The Reformatsky reagent BrZnCH 2 CO 2 t-Bu is prepared in THF by fast activation of zinc with dibromoethane (2-5 mole %) (alternatively, zinc is activated with diluted HCl followed by drying with THF and high vacuum or with tetramethylsilane (1-5%) in THF at 25° C.), followed by reaction with tert-butyl bromoacetate at 50° C. A solution of BrZnCH 2 CO 2 t-Bu is prepared by removing the THF by distillation, followed by dissolution in NMP or DMSO or by filtration of the solid reagent followed by dilution with an aprotic solvent such as NMP or DMSO.
A solution of imine B in NMP (or alternatively in DMSO or THF) is added to a solution of the Reformatsky reagent in an aprotic polar solvent such as THF, NMP, NMP/THF or DMSO, followed by quenching with aqueous ammonium chloride and aqueous hydrochloric acid and subsequent extraction with methyl tert-butyl ether (MTBE) or EtOAc. The organic solution is washed with aqueous ammonium chloride, water and brine to give the amino alcohol C.
The amino alcohol C is reacted with NaIO 4 in the presence of aqueous methylamine in ethanol/water followed by filtration, dilution with toluene, MTBE or THF to give a solution of imine D. Alternatively, the reaction mixture can be concentrated and extracted with MTBE, filtered, dried, filtered and concentrated.!
Imine D is hydrolyzed in the presence of para-toluenesulfonic acid in MTBE (or alternatively in THF or toluene). Precipitation with heptane and filtration afforded the para-toluenesulfonic acid salt E.
Transformation of para-toluenesulfonic acid salt E to hydrochloride salt F is achieved by successive reaction with 0.3 equivalents para-toluenesulfonic acid in ethanol, followed by basic work up (aqueous solution of sodium bicarbonate or potassium bicarbonate) and extraction, with sodium ethoxide in ethanol, with HCl in EtOH (generated by the addition of acetyl chloride in EtOH or dissolution of HCl gas in ethanol) and recrystallization in acetonitrile/MTBE (or alternatively acetonitrile/toluene or acetonitrile/heptane). ##STR17##
In Scheme II aldehyde G (R=alkynyl, alkyl, aryl, substituted aryl, pyridinyl, furanyl) is transformed to imine H by reaction with D or L phenylglycinol in THF or toluene, followed by drying with MgSO 4 , molecular sieves or by azeotropic distillation.
The Reformatsky reagent BrZnCH 2 CO 2 t-Bu is prepared in THF by fast activation of zinc with dibromoethane (1-5 mole %) (alternatively, the zinc is activated with diluted HCl followed by drying with THF and high vacuum or tetramethylsilane (TMS) in THF at 25° C.), followed by reaction with tert-butyl bromoacetate at 50° C. A solution of the reagent is prepared by removing the THF by distillation or decantation followed by dissolution in an aprotic polar solvent such as NMP or DMSO or by filtration of the solid reagent followed by dilution with an aprotic polar solvent such as NMP or DMSO.
A solution of imine H in an aprotic polar solvent such as NMP, DMSO or THF, is added to a solution of the Reformatsky reagent in an aprotic polar solvent such as NMP, NMP/THF, DMSO or THF, followed by acidic aqueous (ammonium chloride/HCl) or basic (ammonium hydroxide) quench and subsequent extraction with MTBE or EtOAc, washing with aqueous ammonium chloride, water and brine to produce the amino alcohol I.
The amino alcohol I is reacted with NaIO 4 in the presence of methylamine in ethanol/water or lead tetraacetate in methanol followed by filtration, dilution with toluene, MTBE or THF to give a solution of imine J. Alternatively, the reaction mixture can be concentrated and extracted with MTBE, filtered, dried, filtered and concentrated.
Imine J is hydrolyzed in the presence of para-toluenesulfonic acid in THF, toluene or MTBE. Precipitation with heptane and filtration afforded the para-toluenesulfonic acid salt K with configuration D (from D-phenylglycinol) or L (from L-phenylglycinol).
Transformation of para-toluenesulfonic acid salt K (R=2-trimethylsilyl-ethynyl) to hydrochloride salt L (R=ethynyl) is achieved by successive reaction with para-toluenesulfonic acid in a solvent such as ethanol, followed by basic work up (aqueous solution of sodium bicarbonate or potassium bicarbonate) and extraction, with sodium ethoxide in an alkanol such as ethanol, with HCl in EtOH (generated by addition of acetyl chloride in an alkanol solvent such as ethanol or dissolution of HCl gas in ethanol) and recrystallization in acetonitrile/MTBE (or alternatively acetonitrile/toluene or acetonitrile/heptane).
Unless otherwise noted the starting materials for the process of this invention are all commercially available or can be prepared according to conventional methods known to those with skill in the art. All equipment employed is commercially available.
The following is a list of definitions and abbreviations used herein:
The terms "alkyl" or "lower alkyl" refer to straight chain or branched chain hydrocarbon radicals having from about 1 to about 6 carbon atoms. Examples of such alkyl radicals include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl, hexyl and the like.
As used herein the terms "alkenyl" or "lower alkenyl" refer to unsaturated acyclic hydrocarbon radicals containing at least one double bond and 2 to about 6 carbon atoms, which carbon-carbon double bond may have either cis or trans geometry. Examples of such groups are ethenyl, propenyl, butenyl, isobutenyl, pentenyl, hexenyl and the like.
As used herein the terms "alkynyl" and "lower alkynyl" refer to acyclic hydrocarbon radicals containing one or more triple bonds and 2 to about 6 carbon atoms. Examples of such groups are ethynyl, propynyl, butynyl, pentynyl, hexynyl and the like.
The term "aryl" as used herein denotes aromatic ring systems composed of one or more aromatic rings, preferably consisting of one or two aromatic rings. The term embraces aromatic radicals such as phenyl, naphthyl, triphenyl, benzofuran and the like.
The term "substituted aryl" as used herein denotes an aryl radical as defined above substituted by one or more substituent selected from the group consisting of alkyl, amino, hydroxy, chloro, fluoro, bromo, alkoxy and nitro.
The terms "pyridyl" or "pyridinyl" are represented by a radical of the formula ##STR18##
The term "furanyl" is represented by a radical of the formula ##STR19##
The term "L-phenylglycinol" refers to a radical of the formula ##STR20## and is used interchangeably with the term (S)-phenylglycinol.
The term "D-phenylglycinol" refers to a radical of the formula ##STR21## and is used interchangeably with the term (R)-phenylglycinol. THF refers to tetrahydrofuran.
NMP refers to N-methylpyrrolidinone.
DMSO refers to dimethylsulfoxide.
NaIO 4 refers to sodium periodate.
NH 4 Cl refers to ammonium chloride.
CH 3 NH 2 refers to methylamine.
EtOH refers to ethanol.
Pb(OAc) 4 refers to lead tetraacetate.
PTSA refers to para-toluenesulfonic acid.
MTBE refers to methyl tert-butyl ether.
NaOEt refers to sodium ethoxide.
EtOAc refers to ethyl acetate.
MgSO 4 refers to magnesium sulfate.
GC refers to gas chromatography.
The present invention provides a safe, convenient and cost effective manufacturing process for the preparation of ethyl 3S-amino-4-pentynoate which is amenable to scale-up. The process utilizes raw materials which are readily available and cost efficient. Its convenience is demonstrated in that the synthetic route does not require either a chromatography or chemical or enzymatic separation of diastereoisomers. Its cost effectiveness is demonstrated by the final products being produced in high yield and a high level of optical purity.
The following non-limiting examples describe and illustrate a method for carrying out the process of the present invention, as well as other aspects of the invention, and the results achieved thereby in further detail. Both an explanation of, and the actual procedures for, the various aspects of the present invention are described where appropriate. These examples are intended to be illustrative of the present invention, and not limiting thereof in either scope or spirit. Those of skill in the art will readily understand that known variations of the conditions and processes described in these examples can be used to perform the process of the present invention.
EXAMPLE 1
αS- 3-(trimethylsilyl)-2-propynylidene!amino!benzenethanol ##STR22##
To a slurry of L-phenylglycinol in toluene (10.00 g, 72.9 mmoles/55 ml), at ambient temperature, was added 1.05 equivalent of 3-(trimethylsilyl)-2-propynal (9.66 g, 76.5 mmoles) at such rate as to keep the temperature below 30° C. The mixture was stirred at ambient temperature for 1 hour. The water was azeotropically removed with toluene under reduced pressure to a final weight of 28.2 g (1.5×the expected yield). At room temperature and with stirring 75 ml of heptane was added and the mixture was cooled to -10° C. for 8 hours. Filtration of the solids by suction followed by a heptane rinse of the cake and air drying produced the solid imine αS- 3-(trimethylsilyl)-2-propynylidene!amino!benzenethanol (80%:15.00 g) in 4:1 ratio of anti to syn isomers (as determined by NMR in THF).
mp 78°-80° C.; 1 HNMR (THF-d8) anti-isomer, δ0.20 (s, 9H) 3.61 (t, 1H, J=6.3 Hz), 3.95 (t, 1H, J=6.3 Hz), 4.18 (t, 1H, J=6.3 Hz), 7.17 (tt, 1H, J=7.3, 1.4 Hz), 7.25 (complex t, 2H, J=7.3 Hz), 7.35 (complex d, 2H, J=7.3 Hz), 7.57 (s, 1H). Syn-isomer, δ0.22 (s, 9H), 3.76-3.63 (complex band, 3H), 5.01 (m, 1H), 7.16 (tt, 1H, 7.3, 1.4 Hz), 7.23 (complex t, 2H, J=7.3 Hz), 7.33 (complex d, 2H, J=7.3 Hz), 7.56 (d, 1H); 13 C NMR (THF-d8) anti-isomer, δ-0.3, 67.9, 79.3, 96.5, 103.5, 127.9, 128.2, 129.0, 141.9, 145.4. Syn-isomer, δ-0.4, 68.6, 73.2, 98.2, 103.6, 127.7, 128.6, 128.9, 142.4, 143.3; IR (MIR) ν (cm-1) 1610, 2370, 2340, 3390, 3610 cm -1 .
Analysis Calculated for C 14 H 19 NOSi: C, 68.52; H, 7.80; N, 5.71. Found: C, 68.59; H, 7.52; N, 5.71.
EXAMPLE 2
BrZnCH 2 CO 2 t-Bu
Step A
A 4 liter jacketed flask, fitted with a condenser, temperature probe and mechanical stirrer was charged with 180 g of Zn metal (-30-100 mesh, 180.0 g, 2.77 mole) and 1.25 L of THF was added to the vessel. While stirring, 1,2-dibromoethane (4.74 mL, 0.055 mole) was added to the vessel via a syringe. The suspension of zinc in THF was heated to reflux (65° C.) and maintained at this temperature for 1 hour. The mixture was cooled to 50° C. before charging the tert-butyl bromoacetate (488 g, 369 mL, 2.5 moles) over a 1.5 hour time period. Controlled reagent addition was performed with a 50 ml syringe and syringe pump (addition rate set at 4.1 mL/min). A temperature of 50° C.±5° C. was maintained during the addition. The reaction mixture was allowed to stir at 50 ° C. for 1 hour after the addition was complete. The reaction mixture was allowed to cool to 25° C., and the agitation turned off to allow the precipitate to settle (the product precipitates from THF solution at 31° C.). The THF mother liquor was removed by decantation into a 2 L round bottom flask under partial vacuum (20 mm Hg) with a dip tube (coarse fritted glass filter). This removed 65% of THF from the vessel, 800 mL of NMP was added and agitation resumed for 5 minutes at 25° C. The reaction mixture was transferred to another vessel by filtration to remove the remaining zinc. Alternatively, the solid reagent can be filtered and dried under N 2 using a pressure funnel. The cake is washed with THF and a white solid was obtained. The solid was dried for 1-2 hours. Typical recovery is 85-90%. The solid can be stored at -20° C. (for at least 6 months).
Step B
Titration Method.
A 1.0 mL aliquot of the Reformatsky-NMP/THF solution was removed from the reaction mixture via syringe and added to a 25 mL round bottom flask which contained a pre-weighed amount of benzaldehyde (250-300 mg) and a magnetic stir bar, under a nitrogen atmosphere. The reaction mixture was stirred for 30 minutes at room temperature. To the flask was added 5.0 mL of aqueous 29% NH 4 Cl and 5.0 mL of methyl t-butyl ether (MTBE). The resulting mixture was stirred for 5 minutes at room temperature. The agitation was stopped and the layers allowed to separate over 5 minutes. A 1.0 mL aliquot of the organic layer was removed and diluted to 25 mL with MTBE in a volumetric flask. This solution was analyzed by gas chromatography (GC) to determine the amount of benzaldehyde which remained. Standard solutions of benzaldehyde in MTBE at concentrations of 0.04M, 0.01M, and 0.002M were co-injected with the sample. The sample concentration was determined from the linearity plot of the standard solutions and the sample GC peak area. The concentration of the Reformatsky solution was determined using the following calculation:
Amount of remaining benzaldehyde=concentration of sample (g/L)*50*5/2
Titer (Mole/L)=Pre-weighted amount of benzaldehyde--amount remaining/106
Yield=Mole/liter*Total volume of solution/Theoretical 100% yield.
Analytical determination of the titer was 1.57 molar with a molar yield of 94% of Example 2.
EXAMPLE 3
1,1-dimethylethyl 3S- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate ##STR23##
A solution of the product of Example 2 in NMP/THF (2.6/1, 1.5 L, 1.57M, 2.4 moles) was charged in a 4 L flask (jacketed, 4 ports fitted with mechanical stirrer, teflon coated temperature probe and addition funnel). The solution was cooled to -10° C. and a solution of the imine of Example 1 (220.0 g, 0.96 mole) in NMP (0.250 L) was added after 30 minutes while the temperature was maintained at -3° C. After total conversion (less than 1% of starting material), as determined by gas chromatography (GC), a mixture of 29% ammonium chloride aqueous solution (1.0 L) and 2N HCl (0.5 L) was added in 15 minutes from -10° C. to 13° C. The mixture was warmed to 25° C. and MTBE (1.0 L) was added. The mixture was stirred for 30 minutes and the layers were separated. The aqueous layer was extracted with MTBE (0.5 L). The organic layers were combined and washed successively with a 29% solution of NH 4 Cl (0.5 L), H 2 O (0.5 L) and brine (0.5 L) and were concentrated under reduced pressure to afford an orange oil (366 g) containing the title compound (84 wt %, 91% yield determined by GC quantitation) 1,1-dimethylethyl 3R- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate, (mixture obtained with a diastereomeric excess (de) of 80% as determined by chiral HPLC).
The two isomers were separated by preparative chiral HPLC for analytical purpose:
Data for 1,1-dimethylethyl 3R- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate: 1 H NMR (CDCl 3 , TMS) δ(ppm) 0.16 (s, 9H); 1.45 (s, 9H), 2.52 (dd (AB), 1H, J=5.6, 15.3 Hz), 2.56 (dd, (AB), 1H, J=5.6, 15.3 Hz), 3.55 (dd, 1H, J=7.7, 5.6 Hz), 3.59 (dd, 1H, J=8.5, 10.7 Hz), 3.74 (dd, 1H, J=4.5, 10.8 Hz), 4.15 (dd, 1H, J=4.5, 8.4 Hz), 7.27 to 7.34 (m, 5H); 13 C NMR (CDCl 3 ) δ(ppm): 0.05, 28.08, 42.22, 44.86, 67.21, 67.47, 80.95, 88.61, 105.00, 127.74, 128.52, 139.69, 170.06; DSC: 79.68° C. (endo. 71.68 J/g), 237.33° C. (exo. 169.0 J/g); α! D 25 =+179.3° (c=0.36, CHCl 3 ); IR (MIR) ν (cm-1) 2167, 1735; UV (methanol) λmax (nm)=204 (abs=0.37); Microanalytical: calcd for C 20 H 31 NO 3 Si: C, 66.44; H, 8.64; N, 3.87. Found: C, 66.34; H, 8.88; N, 3.89.
Data for 1,1-dimethylsilyl 3S- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylethyl)-4-pentynoate: 1 H NMR (CDCl 3 , TMS) δ(ppm) 0.09 (s, 9H); 1.46 (s, 9H), 2.49 (dd (AB), 1H, J=8.6, 15.6 Hz), 2.59 (dd, (AB), 1H, J=5.1, 15.6 Hz), 3.59 (dd, 1H, J=6.5, 11.1 Hz), 3.77 (dd, 1H, J=4.5, 11.1 Hz), 3.89 (dd, 1H, J=5.1, 8.7 Hz), 3.97 (dd, 1H, J=5.1, 8.7 Hz), 7.24 to 7.36 (m, 5H); 13 C NMR (CDCl 3 ) δ(ppm): -0.11, 28.07, 42.26, 46.15, 62.10, 65.48, 81.16, 88.28, 105.99, 127.33; DSC: 252.27° C. (exo. 342.3 J/g); α! D 25 =-5.6° (c=1.024, CHCl 3 ); IR (neat) ν (cm-1) 2167, 1735; UV (methanol) λmax (nm)=205 (abs=0.33);
Microanalytical: calcd for C 20 H 31 NO 3 Si: C, 66.44; H, 8.64; N, 3.87. Found: C, 66.22; H, 8.82; N, 3.85.
EXAMPLE 4
1,1-dimethylethyl 3S- (phenylmethylene)amino!-5-trimethylsilyl)-4-pentynoate ##STR24##
NaIO 4 (77.0 g, 0.36 mole) was charged into a flask (500 mL) followed by H 2 O (0.330 L) and the mixture was stirred for 30 minutes at 25° C. A solution of 1,1-dimethylethyl 3S- (2-hydroxy-1S-phenylethyl)-amino!-5-(trimethylethyl)-4-pentynoate of Example 3 (116.3 g, 86 wt %, 0.277 mole) in ethanol (0.520 L) was charged into a 1 L flask (4 ports, jacketed, fitted with mechanical stirrer and teflon coated temperature probe) purged with N 2 , followed by addition of a solution of methylamine (40 wt %, 24 mL, 0.278 mole). After 5 minutes of stirring at 25° C., a slurry of NaIO 4 in H 2 O was added portionwise while maintaining a temperature below 35° C. (32°±2° C.). After complete addition, conversion was complete and the mixture was cooled to 3° C. and held at this temperature for 3 hours. The mixture was filtered on a pressure filter (extra coarse, 600 mL) and the cake was dried for 3.5 hours under a N 2 vacuum (Karl-Fisher analysis showed 5.60% H 2 O remaining). The cake containing a mixture of the title compound and iodate salt was charged into a flask (500 mL) and toluene (130 mL) was added. After 30 minutes of stirring at 30° C. the mixture was filtered. The cake was washed twice with toluene (2×50 mL). The 3 fractions were combined and partially concentrated to a weight of 161 g containing 53.3 wt % of the title compound (determined by GC quantitation) with a yield of 92% and a chiral purity of 99.9% (determined by chiral HPLC). A sample was isolated for full characterization by concentration of the solution:
1 H NMR (CDCl 3 , TMS) δ(ppm) 0.20 (s, 9H); 1.45 (s, 9H), 2.66 (dd (AB), 1H, J=7.0, 15.0 Hz), 2.80 (dd, (AB), J=7.7, 15.0 Hz), 4.83 (dt, 1H, J=1.7, 7.6 Hz), 7.38 to 7.44 (m, 3H), 7.74 to 7.77 (m, 2H), 8.56 (d, 1H, J=1.5 Hz); 13 C NMR (CDCl 3 ) δ(ppm): 0.02, 28.09, 43.20, 56.46, 80.75, 92.53, 103.15, 128.47, 128.54, 130.90; 135.90, 161.78, 169.55; DSC: 72.22° C. (endo. 112.4 J/g); α! D 25 =-35.5° (c=1.16, CHCl 3 ); IR (MIR) ν (cm-1) 2174, 1728, 1641; UV (methanol) λmax (nm)=205 (abs=1.004), 248 (abs=0.655); Microanalytical: calcd for C 19 H 27 NO 2 Si: C, 69.26; H, 8.26; N, 4.25. Found: C, 69.10; H, 8.43; N, 4.33.
EXAMPLE 5
1,1-Dimethylethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate 4-methylphenylsulfonate salt ##STR25##
A solution of the product of Example 4 (123.3 g, 0.374 mole) in dry THF (350 mL) was prepared. p-Toluenesulfonic acid monohydrate (71.2 g, 0.374 mole) was charged to a 4 L jacketed reaction vessel under nitrogen. An overhead stirrer with a 10 cm teflon stir blade was attached. A thermocouple thermometer was put in place. The reactor jacket was cooled to 0° C. The solution of the product of Example 4 was added via an addition funnel over 5 minutes with stirring at 250 rpm. The reaction temperature rose to 10° C. The addition funnel was rinsed with THF (300 mL). After stirring for 15 minutes the mixture became homogeneous. The stirring rate was increased to 350 rpm. Skellysolve C heptanes (1360 mL) was added over 5 minutes. The product crystallized and the agitation was increased to 540 rpm. The solvent was distilled from the reactor under vacuum under the following conditions. An oil pump connected to a vacuum regulator which was used to adjust the vacuum to 45 mm Hg. The jacket temperature was set to 20° C. and a dry ice/isopropanol condenser with 2 L receiving flask was used to collect the distillate. The distillate collected was 900 mL. The reactor was placed under a nitrogen atmosphere and further heptanes (900 mL) were added. The slurry was cooled to 2° C. The solids were collected on a 10 cm coarse glass fritted filter using vacuum. The reaction vessel was rinsed by adding heptanes (500 mL) and THF (50 mL) with stirring. The reaction mixture was cooled to 10° C. and added to the filter. The cake was washed with heptanes (3×300 mL) and dried by using a combination of vacuum and nitrogen flow for 4.5 hours to produce the title compound (145.9 g, 94%): mp. 142° C.;
1 H NMR (CDCl 3 , 400 MHz) δ8.32 (br, s, 3H), 7.79 (d, J=8.0 Hz, 2H), 7.15 (d, J=8.0 Hz, 2H), 4.40 (dd, J=8.0, 6.0 Hz, 1H), 2.89 (dd, J=17.0, 8.0 Hz, 1H), 2.76 (dd, J=17.0, 5.0 Hz, 1H), 2.36 (s, 3H), 1.41 (s, 9H), 0.10 (s, 9H); 13 C NMR (CDCl 3 , 125 MHz) δ168.60, 141.55, 140.22, 128.81 (2C), 126.11 (2C), 98.51, 92.71, 82.02, 40.56, 38.56, 27.95 (3C), 21.31, -0.53 (3C); Analysis Calculated for C 19 H 31 NO 5 SSi: C, 55.17; H, 7.55; N, 3.39. Found: C, 55.27; H, 7.27; N, 3.34.
EXAMPLE 6
ethyl 3S-amino-4-pentynoate, monohydrochloride salt ##STR26##
A solution of the product of Example 5 (500.0 g, 1.21 mol) and p-toluenesulfonic acid monohydrate (69.5 g, 0.365 mol) in ethanol (930 mL) was heated to reflux and held for 4 hours. Reaction completion was determined by GC. The reaction mixture was concentrated in vacuo. MTBE (1200 mL) was charged to the concentrate with stirring to afford complete dissolution. A 20 wt/wt % potassium bicarbonate aqueous solution (1387 g) was added to the MTBE solution. The biphasic mixture was stirred for 15 minutes. The aqueous layer was back-extracted with MTBE (700 mL). The combined organic layers were extracted a second time with a 20 wt/wt % potassium bicarbonate aqueous solution (306 g). The organic layer was concentrated in vacuo. Water was removed azeotropically with ethanol (900 mL) under reduced vacuum. An 87% yield of the desired silyl protected free amine was obtained 1.06 mol!. To the concentrate was charged ethanol 2B (600 mL), followed by 21 wt % sodium ethoxide (in ethanol denatured with 5% toluene) (39.6 mL, 0.106 mol, 0.1 equivalent sodium ethoxide). The reaction solution was allowed to cool to room temperature and stirred for one-half hour. Desilylation completion was determined by GC. In a separate vessel was charged ethanol 2B (720 mL), followed by acetyl chloride (81.6 mL, 1.15 mol, 1.1 equivalent). This addition was carried out over 20 minutes, not allowing the temperature to rise above 45° C. The solution was then cooled to 20°-25° C. The resulting hydrogen chloride/ethyl acetate/ethanol solution was charged to the desilylation reaction mixture. The reaction mixture was cooled to 25° C. with stirring over a 30 minute period and then stirred at 25° C. for an additional 30 minutes. The reaction mixture was concentrated under reduced pressure. The concentrate was cooled to room temperature and toluene (920 mL) was added. The mixture was stirred for 20 minutes and then concentrated in vacuo. Toluene (920 mL) was added to the concentrate and stirred for 20 minutes. Solids were collected by filtration and dried affording 184.94 g of crude title compound (86.1% yield).
A portion of the crude title compound (80.0 g) was recrystallized from acetonitrile/MTBE. To 80.0 g of crude title compound was added 400 mL acetonitrile. The mixture was heated to reflux and the resulting heated opaque yellow solution was filtered through 20 g celite which had been washed with 160 mL hot acetonitrile. The filtrate was concentrated in vacuo removing 195 mL of solvent. The concentrated solution was cooled to 45° C. To the solution was added 195 mL of MTBE. The resulting opaque mixture was heated to reflux, cooled to 50° C. and stirred for 15 minutes. The mixture was cooled to 40° C. and held for 15 minutes. The mixture was then allowed to cool to 22° C. and filtered. The resulting solids were rinsed with 2×80 mL MTBE. The solids were dried on the filter for 10 minutes, then under high vacuum for 2 hours, providing 72.18 g of the title compound.
1 H NMR (D 6 -DMSO) δ(ppm) 1.21 (t, 3H, J=7 Hz), 2.84 (dd, 1H, J=9, 16 Hz), 3.03 (dd, 1H, J=5, 16 Hz), 3.70 (d, 1H, J=2Hz), 4.13 (q, 2H, J=7 Hz), 4.31 (m, 1H), 8.82 (s, 3H); 13 C NMR (D 6 -DMSO) δ(ppm): 13.95, 37.58, 38.40, 60.71, 77.99, 78.63, 168.42; DSC: 125°-131° C. (endo. 107.2 J/g); α! D 25 =-6.7; IR (MIR) ν (cm -1 ) 3252, 2128, 1726;
Microanalytical: calcd for C 7 H 12 NO 2 Cl: C, 47.33; H, 6.81; N, 7.89; Cl, 19.96: Found: C, 47.15; H, 6.84; N, 7.99; Cl, 19.55. ##STR27##
Scheme III depicts the preparation of other β-amino esters using the process of the present invention as described hereinafter.
EXAMPLE 7 ##STR28##
(S)-Phenyl glycinol (11.74 g, 0.086 mole) was charged in a 500 mL 3N RB flask fitted with a mechanical stirrer, followed by addition of toluene (110 ml). The flask was vacuum/flushed with nitrogen. 3,5-dichlorobenzaldehyde (15.0 g, 0.086 mole) was added. After 15 minutes at 22° C., MgSO 4 (15 g) was added (exothermic reaction). The mixture was stirred for 1 hour at 22° C., filtered on a coarse fritted filter. The cake was washed with toluene (20 ml). The solutions were combined and concentrated under reduced pressure to afford 27.00 g of a pale yellow oil containing the imine 1a. No further purification was performed and the crude product was used directly in the coupling reaction. 1 H NMR (CDCl 3 ), TMS) mixture of imine and oxazoline 4/1. (ppm):(imine) 3.88 to 3.99 (m, 2H), 4.50 (dd, 1H, J=4.7, 8.1 Hz) 7.67 (d, 2H), 8.28 (s, 1H):oxazoline: 5.55 and 5.70 (s, 0.5+0.5H), 3.72 to 3.83 (m, 0.5+0.5 H), 4.30 to 4.35 (m, 0.5+0.5H), 4.40 to 4.48 (m, 0.5H), 4.54 to 4.60 (m, 0.5H), mixed protons: 7.15 to 7.47 (m(aromatic+CDCl 3 )); 13 C NMR (CDCl 3 , TMS) (ppm):imine: 67.55, 76.38, 135.13, 138.70, 140.05, 159.72. Oxazoline: 60.60, 62.80, 72.12, 72.34, 91.05, 91.68, 135.03, 135.41, 142.62. Mixed signals: (aromatics) 124.86, 124.956, 125.33, 126.53, 126.65, 126.75, 127.38, 127.74, 127.77, 128.11, 128.26, 128.32, 128.72, 128.84, 128.93, 129.06, 130.64.
EXAMPLE 8 ##STR29##
A1 L jacketted 3 ports reactor with bottom valve, fitted with a mechanical stirrer and an addition funnel was charged with a solution of Reformatsky reagent from Example 2 (189 mmoles, 165 ml, 1.15M). The solution was then cooled to -10° C. A solution of imine from Example 7 (25.39 g, 85.8 mmoles) in NMP (60 ml) was prepared under nitrogen and charged in the addition funnel. The solution of imine was then added in 5 minutes while the temperature was maintained at -5° C. (jacket at -10° C.). The reaction was monitored by GC and TLC (elution heptane/EtOAc 30%). After 5 minutes the reaction was almost complete (trace of starting material). The mixture was stirred for an additional hour and a mixture of 2N HCl/saturated solution of NH 4 Cl (1/2, 135 ml) was added. MTBE (200 ml) was added and the mixture was stirred for 1 hour at 23° C. Stirring was stopped and the layers were separated. The aqueous layer was extracted with MTBE (100 ml). The two organic layers were combined, washed successively with a saturated solution of N 4 Cl (140 ml), water (140 ml) and brine (140 ml). The solution was dried with MgSO 4 (30 g), filtered and concentrated to afford 35.2 g of an orange oil containing the desired product 2a as a single diastereoisomer (by 1 H NMR).
In a separate reaction (28.6 mmole scale) the crude product (11.36 g) was purified by chromatography (SiO2, 200 g), elution heptane/EtOAc 30%) to afford the desired compound 2a as a pale yellow oil (10.07 g, 85%). 1 H NMR (CDCl 3 , TMS) δ(ppm) 1.40 (s, 9H), 2.56 (dd (AB), 1H, J=5.6, 15.4 Hz), 2.56 (dd (AB), 1H, J=8.1, 15.6 Hz), 2.60 (s(broad), 1H), 3.62 (dd (AB), 1H, J 6.8, 10.7 Hz), 3.72 (dd, 1H, J=4.2, 6.8 Hz), 3.80 (dd (AB), 1H, J=4.2, 6.8 Hz), 4.11 (dd, 1H, J=5.8, 7.9 Hz), 7.09 to 7.29 (m, 8H, (aromatic)); 13 C NMR (CDCl 3 , TMS) δ(ppm):28.00, 42.98, 57.28, 62.24, 65.99, 81.42, 125.69, 127.21, 127.35, 127.60, 128.48, 134.83, 140.78, 146.44, 170.58; DSC: 241.46° C. (endo. 180.1 J/g); α! D 25 =+6.9° (c=1.025, CHCl 3 ); IR (MIR) (cm-1) 1726, 1587, 1567.
Microanalytical: calcd for C 21 H 25 Cl 2 NO 3 : C: 61.47; H: 6.14; N: 3.41; Cl: 17.27 Found: C: 59.95; H: 6.51; N: 3.11; Cl: 16.00
EXAMPLE 9 ##STR30##
A solution of crude ester from Example 8 in EtOH (140 ml) was charged to a 500 ml round bottom 3N flask. A solution of methyl amine (8.9 ml, 0.1 mole) was added. A slurry of NaIO 4 (0.112 mole, 25.92 g) in H 2 O (72 ml) at 25° C. was added by portion while maintaining a temperature of 30° C. (±2° C.). The reaction was monitored by TLC. The reaction mixture was then stirred at room temperature for 15 hours. NaIO 4 (6 g, 0.026 mole) solid was added. After 4 hours, NaIO 4 (6 g, 0.026 mole) solid was added and the mixture was heated at 30° C. for 0.5 hour. After cooling to 25° C., the reaction mixture was concentrated under reduced pressure (water aspirator). MTBE was added and the mixture was filtered through a coarse glass fritted filter. The layers were separated and the organic layer was washed with H 2 O (100 ml) dried with MgSO 4 (25 g), filtered and concentrated under reduced pressure to afford 30.2 g of an orange oil containing compound 3a.
EXAMPLE 10 ##STR31##
The crude mixture containing 3a was diluted with THF (65 ml) and was charged in a 500 ml round bottom 3N flask fitted with a mechanical stirrer and an addition funnel. A solution of p-toluenesulfonic acid monohydrate (13.6 g, 71.6 mmole) in THF (20 ml) was then added in 2 minutes followed by a wash of THF (5 ml) via the addition funnel. After 5 minutes, heptane (65 ml) was added and heavy precipitation occurred. Additional heptane (65 ml) was added. After 0.5 hour, the slurry was filtered through a coarse glass fritted pressure filter and was washed with heptane/THF 20% (100 ml) and heptane/THF 33% (150 ml). The cake was then dried under vacuum/nitrogen for 2 hours. The ivory solid 4a was collected to afford 25.1 g (63% overall yield from example 7) of the desired compound. 1 H NMR (CDCl 3 , TMS) (ppm) 1.26 (s, 9H), 3.37 (s, 3H), 2.84 (dd, (AB), J=9.5, 16.3 Hz), 2.98 (dd, (AB), J=5.2, 16.2 Hz), 4.53 (m, 1H), 7.14 (d, 2H, J=7.9 Hz), 7.19 (t, 1H, J=1.8 Hz), 7.32 (d, 2H, J=8.1 Hz), 7.56 (d, 2H, J=8.1 Hz), 8.43 (s(broad), 3H); 13 C NMR (CDCl 3 , TMS) δ(ppm): 21.37, 27.80, 39.47, 51.36, 81.85, 125.77, 126.43, 129.01, 129.06, 135.17, 139.14, 140.59, 140.69, 168.06. DSC: 120.30° C. (80.71 J/Kg), 242.63 (endothermic, 100.3 J/g) α! D 25 =+37.4 (c=0.147, CHCl 3 ); IR (MIR) (cm-1) 1726, 1587, 1567.
Microanalytical: found for C 20 H 25 Cl 2 NO 2 S: C: 51.65; H: 5.64; N: 3.01; Cl: 15.13; S: 7.00 Calcd: C: 51.95; H: 5.45; N: 3.03; Cl: 15.33; S: 7.02.
EXAMPLE 11 ##STR32##
Following the general procedure for the preparation of imine described in Example 7 the compound 1b was prepared from S-phenyl glycinol (27.44 g, 0.2 mole), benzaldehyde (21.75 g, 0.205 mole) in toluene (200 mL) and MgSO 4 (8.0 g). The crude mixture was slurried in heptane (100 mL) and filtered to afford the compound 1b as a white solid (40.07 g, 88.9%).
EXAMPLE 12 ##STR33##
Following the general procedure for the Reformatsky coupling described in Example 8, compound 2b was prepared from a solution of Reformatsky reagent from Example 2 (1.38M in NMP/THF(3/2), 0.22 mole, 160 mL) and imine 1c (22.53 g, 0.1 mole) in NMP (20 mL) to afford a yellow oil (33.24 g, 97.3%) containing the compound 2b as a single diastereoisomer (as determined by 1 H NMR and GC). The crude product was not purified and was used directly in the next step.
A sample of the crude product was purified by chromatography (SiO 2 , 300 g), elution heptane/EtOAc 40%) to afford the desired compound as a pale yellow oil. 1 H NMR (CDCl 3 , TMS) δ(ppm) 1.40 (s, 9H), 2.60 (dd, 1H (AB), J=5.8, 15.3 Hz), 2.67 (dd, 1H (AB), J=8.515 4Hz), 3.58 (dd, 1H, J=6.2, 10.9 Hz), 3.71 (dd, 1H, J=6.3, 4.4), 3.84 (dd, 1H, J=4.3, 10.9 Hz), 4.19 (dd, 1H (AB), J=5.8, 8.3 Hz), 7.18 to 7.29 (m, 10H); 13 C NMR (CDCl 3 , TMS) δ(ppm):28.01, 43.54, 57.39, 61.21, 80.90, 126.92, 127.17, 127.34, 127.37, 128.44, 128.47, 141.61, 142.60, 171.25;
DSC:226.60° C. (endo. 113.1 J/g); α! D 25 =+19.5° C. (c=1.2, CHCl 3 ); IR (MIR) (cm-1) 1720.
Microanalytical: calcd for C 21 H 27 NO 3 : C: 73.87; H: 7.97; N: 4.10 Found: C: 73.87; H: 7.94; N: 3.97.
EXAMPLE 13 ##STR34##
Following the general procedure for the oxidative cleavage as described in Example 9, the imine 3b, was prepared from NaIO 4 (19.57 g, 0.091 mole) and methyl amine (40 wt % in H 2 O, 5.56 mL, 0.77 mole), and amino alcohol (27.37 g, 0.075 mole, crude) in ethanol (105 mL), H 2 O (65 mL) (17 hours). After work up and concentration, a crude mixture (19.8 g) was obtained containing the phenyl imine 3b.
EXAMPLE 14 ##STR35##
The phenyl imine 3b of Example 13 was hydrolyzed in THF (50 mL) following the general procedure for the preparation of PTSA salt described in Example 10 with a solution of PTSA.H 2 O (10.72 g, 0.057 mole) in THF (15 mL). Heptane (100 mL) was added and the mixture heated to 35° C. for 30 minutes followed by slow cooling to 0° C. Filtration and washes with THF 30%/heptane (100 mL) afforded the desired salt 4b (19.28 g, 49% overall yield from Example 12) as an ivory solid.
1 H NMR (DMSO D6, TMS) δ(ppm) 1.26 (s, 9H), 2.29 (s, 3H), 2.81 (dd, 1H, J=9.2, 15.6 Hz) 2.99 (dd, 1H, J=5.8, 15.8 Hz), 4.55 (m, 1H), 7.11 (d, 2H, 7.8 Hz), 7.38 to 7.49 (m, 8H), 8.31 (s(broad), 3H); 13 C NMR (DMSO D6, TMS) δ(ppm):20.77, 27.45, 51.20, 80.84, 125.48, 127.69, 128.18, 128.58, 128.88, 136.41, 138.06, 145.00, 168.05.
DSC:107.62° C. (endo 177.9 J/Kg), 161.73 (endo, 2.77 J/g), 174.49 (endo 9.54 J/g), 236.51 (endo 354.2 J/g) α! D 25 =-2.50 (c=0.91, CHCl 3 ); IR (MIR) (cm-1) 1725.
Microanalytical: calcd for C 20 H 27 NO 5 S: C: 61.05; H: 6.92; N: 3.56; S: 8.15 found: C: 60.13; H: 7.03; N: 3.53; S: 8.46.
MS-CDI/NH 3 /CH 4 M+2 223, M+1 222, 166, 149, 106.
EXAMPLE 15 ##STR36##
Following the general procedure for the preparation of imine described in Example 7, compound 1c was prepared from S-phenyl glycinol (27.44 g, 0.2 mole), 3-pyridinecarboxaldehyde (21.96 g, 0.205 mole) in toluene (120 mL) with MgSO 4 (8 g). The crude imine was slurried in heptane (100 mL), stirred for 2 hours and filtered to afford 42.25 g (93.3% yield) of the imine 1c as a white powder.
EXAMPLE 16 ##STR37##
Following the general procedure for the Reformatsky coupling described in Example 8, compound 2c was prepared from a solution of Reformatsky reagent of Example 2 (1.36 M in NMP/THF(3/2), 0.164 mole, 121 mL) and imine 1c from Example 15 (17.0 g, 0.075 mole) in NMP (20 m). Regular extraction yielded 17 g of a crude mixture. Additional extractions were performed. A saturated solution of ammonium chloride (50 mL) was added to the aqueous layer followed by MTBE extraction. This procedure was repeated. The MTBE layers were combined and washed as in the general procedure to yield an additional 10.35 g of a crude mixture. The crude mixtures were combined to afford 27.85 g (25.69 g, 100%) of an orange oil containing the compound 2c as a single diastereoisomer (as determined by 1 H NMR and GC). The crude product was not purified and was used directly in the next step.
A sample of crude product was purified by chromatography (SiO 2 , 50 g), elution heptane/EtOAc 60%) and recrystallized from MTBE/heptane (4/1) to afford the desired compound as a white solid. 1 H NMR (CDCl 3 , TMS) δ(ppm) 1.38 (s, 9H), 2.60 (dd(AB), 1H, J=5.7, 15.6 Hz), 2.71 (dd(AB), 1H, J=8.1, 15.5 Hz), 3.60 (dd(AB), 1H, J=6.8, 10.5 Hz), 3.72 to 3.80 (m, 2H), 4.20 (dd, 1H, J=5.8, 8.1 Hz), 7.13 to 7.23 (m, 6H, (aromatic)), 7.62 (dt, 1H, J=1.8, 8.0 Hz), 8.46 (dd, 1H, J=1.6, 5.0 Hz), 8.54 (d, 1H, J=1.9 Hz); 13 C NMR (CDCl 3 , TMS) δ(ppm): 26.72, 27.75, 27.84, 42.46, 55.59, 62.83, 66.10, 81.07, 123.58, 127.16, 127.25, 128.17, 136.11, 139.40, 140.66, 147.60, 148.32, 170.19; DSC: 8 5.75° C. (endo. 133.4 J/g); α! D 25 =±17.30° (c=1.035, CHCl 3 ); IR (MIR) (cm-1) 1718. UV max (nm)=205 (abs=0.48), 261 (abs=0.096), 268 (abs=0.073)
Microanalytical: calcd for C 20 H 26 N 26 O 3 : C: 70.15; H: 7.65; N: 8.18 Found: C: 70.24; H: 7.79; N: 8.02.
EXAMPLE 17 ##STR38##
Following the general procedure for the oxidative cleavage, described in Example 9, the imine 3c was prepared from NaIO 4 (19.57 g, 0.091 mole), methyl amine (40 wt % in H 2 O, 5.56 mL, 0.77 mole), and amino alcohol 2c (27.37 g, 0.075 mole, crude) in ethanol (105 mL), H 2 O (65 mL) (17 hours). After work up and concentration, a crude product (19.8 g) was obtained containing the phenyl imine 3c.
EXAMPLE 18 ##STR39##
The phenyl imine 3c was hydrolyzed in THF (50 mL) following the general procedure for the formation of PTSA salt described in Example 10 with a solution of PTSA:H 2 O (10.72 g, 0.057 mole) in THF (15 mL). Heptane (100 mL) was added and the mixture heated to 35° C. for 30 minutes followed by slow cooling to 0° C. Filtration and wash with THF 30%/heptane (100 mL) afforded the desired salt 4c (19.28 g, 65% overall yield from Example 16) as an ivory solid.
1 H NMR (CDCl 3 , TMS) δ(ppm) 1.24 (s, 9H), 2.35 (s, 3H), 2.90 (dd, 1H, (AB), J=8.87, 16.6 Hz), 3.09 (dd, 1H (AB), J=5.8, 16.6 Hz), 4.71 (dd, 1H, J=6.0, 8.9 Hz), 7.09 (d, 2H, J=7.9 Hz), 7.19 (dd, 1H, J=4.9, 7.9 Hz), 7.57 (d, 2H, J=8.1 Hz), 7.99 (dd, 1H, 1.7, 8.1 Hz), 8.46 (dd, 1H, J=1.4, 5.0 Hz), 8.70 (d, 1H, 1.9 Hz); 13 C NMR (CDCl 3 , TMS) δ(ppm) : 21.30, 27.72, 38.99, 49.86, 81.95, 124.16, 125.84, 128.95, 132.52, 137.18, 140.46, 141.22, 148.28, 148.57, 168.34. DSC: 113.62° C. (endo 68.41 J/Kg), 159.9 (endo, 62.88 J/g) α! D 25 =-1.5 (c=0.998, CHCl 3 );
IR (MIR) (cm-1) 2116, 1721, 1540.
Microanalytical: found for C 19 H 26 N 2 O 5 S: C: 57.85; H: 6.64; N: 7.10; S: 8.13 calcd: C: 57.15; H: 6.46; N: 6.44; S: 8.38.
MS-CDI/NH 3 /CH 4 M+2 224, M+1 223, 195, 167, 150, 107.
EXAMPLE 19 ##STR40##
Following the general procedure for the preparation of imine described in Example 7, compound 1e was prepared from L-phenylglycinol (10.00 g, 0.073 mole) and trimethylacetaldehyde (6.59 g, 0.076 mole) in toluene (50 mL) with MgSO 4 as drying agent (2.7 g) to afford imine 1e (14.41 g) as a clear oil which was used in the following Example without further purification.
EXAMPLE 20 ##STR41##
A solution of the imine 1e in DMSO (30 mL) was added in 15 minutes to a solution of Reformatsky reagent from Example 2 (57.50 g, 0.173 mole) in DMSO (80 mL) while cooling to 8° C. After addition the mixture was held at 22° C. and stirred for 22 hours. Reformatsky reagent from Example 2 (23.00 g, 0.069 mole) was then added as a solid. The mixture was stirred at 22° C. for an additional 8 hours (89% conversion by GC). A saturated aqueous solution of NH 4 Cl (100 mL) was then added and the mixture extracted with MTBE (2×100 mL). The organic layers were combined, washed with a saturated solution of NH 4 Cl (100 mL), H 2 O (100 mL), brine (100 mL) and dried with Na 2 SO 4 . Filtration and concentration afforded a crude mixture of yellow oil (17.57 g) containing the compound 2e which was used without purification in the following Example. A sample of product was purified by chromatography (SiO 2 , 300 g), elution heptane/EtOAc 40%) to afford the desired compound as a pale yellow oil. 1 H NMR (CDCl 3 , TMS) δ(ppm) 0.83 (s, 9H), 1.46 (s, 9H), 2.24 (dd(AB), 1H, J=5.4, 15.4 Hz), 2.51 (dd(AB), 1H, 5.3, 15.5 Hz), 2.67 (t, 1H, J=5.4 Hz), 3.53 (dd(AB), 1H, J=9.0, 10.8 Hz), 3.67 (dd, 1H, J=4.3, 10.8 Hz), 3.85 (dd, J=4.27, 8.8 Hz), 7.23 to 7.34 (m, 5H); 13 C NMR (CDCl 3 , TMS) δ(ppm):26.68, 28.06, 35.04, 37.87, 60.80, 62.73, 67.33, 80.48, 127.42, 127.75, 128.35.
Microanalytical: calcd for C 19 H 31 NO 3 : C: 70.99; H: 9.72; N: 4.36 Found: C: 69.91; H: 9.98; N: 4.15.
EXAMPLE 21 ##STR42##
The crude product containing compound 3e from Example 20 was diluted with MeOH (520 mL), cooled to 0° C. and Pb(OAc) 4 (23.40 g, 0.0536 mole) was added. The resulting orange solution was stirred for 1 hour at 0° C. A 15% aqueous solution of NaOH (100 mL) was added and the mixture was held at 22° C. and concentrated under reduced pressure to remove MeOH. MTBE was added, the mixture filtered and the layers were separated. The organic layer was dried with NaSO 4 , filtered and concentrated to afford 14.30 g of a yellow oil containing 3e.
EXAMPLE 22 ##STR43##
The crude oil containing 3e from Example 21 was dissolved in MTBE (38 mL) and paratoluene sulfonic acid (8.24 g, 0.043 g) was added. After 15 minutes, heptane (150 mL) was added and the resultant slurry was filtered to afford 13.86 g of a white solid containing the salt with some impurities. The compound was purified by reslurrying in MTBE/heptane followed by filtration under nitrogen/vacuum (pressure filter) to yield 11.83 g of product 4e (43.4% overall yield from Example 19).
1 H NMR (CDCl 3 , TMS) δ(ppm) 1.01 (s, 9H), 1.41 (s, 1H), 2.35 (s, 3H), 2.55 (dd, 1H, J=4.0, 17.7 Hz), 2.66 (dd, 1H, J=9.0, 17.6 Hz), 3.28 (m, 1H), 7.15 (d, 2H), 7.75 (d, 2H), 7.80 (s(broad), 3H); 13 C NMR (DMSO D6, TMS) δ(ppm):21.28, 26.00, 27.92, 33.22, 33.83, 57.38, 82.12, 126.08, 128.70, 139.92, 141.98, 170.96 DSC: 117.11° C. (endo 65.14 J/Kg), 147.84° C. (endo 93.35 J/g); α! D 25 =-24.7° (c=0.777, CHCl 3 ); IR (MIR) (cm-1) 1718.
Microanalytical: calcd for C 18 H 31 NO 5 S: C: 57.88; H: 8.37; N: 3.75; S: 8.58 Found: C: 57.64; H: 8.46; N: 3.58; S: 8.80.
EXAMPLE 23 ##STR44##
Following the general procedure for the preparation of imine described in Example 22, compound 1f was prepared from L-phenylglycinol (10.00 g, 0.073 mole) and isobutyraldehyde (6.59 g, 0.076 mole) in toluene (50 mL) with MgSO 4 as drying agent (2.9 g) to afford 15.40 g of imine 1f as a yellow oil which was used without further purification in the following Example.
EXAMPLE 24 ##STR45##
A solution of the imine 1f produced in Example 23 in DMSO (30 mL) was added over 15 minutes to a solution of Reformatsky reagent from Example 2 (57.50 g, 0.173 mole) in DMSO (80 mL) while cooling to 8° C. The mixture was held at 22° C. and stirred for 16 hours. Additional Reformatsky reagent from Example 2 (2.50 g, 0.008 mole) was then added as a solid and the mixture was stirred at 22° C. for an additional 4 hours (92% conversion by GC). A saturated aqueous solution of NH 4 Cl (100 mL) was then added and the mixture extracted with MTBE (2×100 mL). The organic layers were combined, washed with a saturated solution of NH 4 Cl (100 mL), H 2 O (100 mL), brine (100 mL) and dried with Na 2 SO 4 . Filtration and concentration afforded (20.1 g, 85.65% overall yield from Example 23) a yellow oil containing the compound 2f which was used without further purification. A sample of product was purified by chromatography (SiO 2 , 300 g), elution heptane/EtOAc 40%) to afford the desired compound 2f as a pale yellow oil. 1H NMR (CDCl 3 , TMS) δ(ppm) 0.68 (d, 3H, J=6.5 Hz), 0.83 (2H, J=6.6 Hz), 1.19 (m, 1H), 1.32 (m, 1H), 1.46 (s, 9H), 1.61 (s, 1H), 2.26 (dd(AB), 1H, J=5.70, 14.62 Hz), 2.38 (dd(AB), 1H, J=5.71, 14.57 Hz), 2.92 (m, 1H), 3.51 (dd(AB), 1H, J=10.75, 8.54 Hz), 3.69 (dd(AB), 1H, J=4.32, 10.72 Hz), 3.84 (dd, 1H, J=8.49, 4.44 Hz), 7.23 to 7.35 (m, 5H); 13 C NMR (CDCl 3 , TMS) δ(ppm):22.26, 22.94, 24.68, 28.13, 40.41, 44.95, 50.47, 61.77, 67.00, 80.55, 127.29, 127.49, 128.50, 141.51, 171.96. DSC: 171.62° C. (endo. 36.3 J/g), 224.06° C. (234.5 J/g), 281.65° C. (endo 234.5 J/g); α! D 25 =+49° (c=1.005, CHCl 3 ); IR (MIR) (cm-1) 3428, 3331, 1721.
Microanalytical: calcd for C 19 H 31 NO 3 : C: 70.99; H: 9.72; N: 4.36 Found: C: 69.29; H: 9.75; N: 4.08.
EXAMPLE 25 ##STR46##
Freshly distilled 2-furaldehyde (26.73 g; 0.278 moles) was dissolved in toluene (100 mL) under nitrogen in a 500 mL 3-neck flask with magnetic stirring. A thermocouple thermometer was put in place. L-phenylglycinol (38.16 g; 0.278 mole) was added. The mixture was stirred for 30 minutes with ice cooling. Magnesium sulfate (33.5 g; 0.278 moles) was added. After stirring a further 30 minutes the magnesium sulfate was removed by filtration. The solvent was removed by rotary evaporation. Heptane (100 mL) was added with stirring. The resulting yellow solid was dried under vacuum (54.72 g; 91.4%).
1 H NMR (400 MHz, CDCl 3 ) δ8.17 (s, 1H), 7.54 (d, J=1.75 Hz), 7.43-7.25 (m, 5H), 6.78 (dd, J=3.4, 0.7 Hz, 1H), 6.48 (dd, J=3.4, 1.8 Hz, 1H), 4.43 (dd, J=8.6, 4.5 Hz, 1H), 4.03 (dd, J=11.3, 8.6 Hz, 1H), 3.90 (dd, J =11.3, 4.4 Hz, 1H). 13 C NMR (CDCl 3 ) δ151.52, 151.16, 144.99, 140.42, 128.61, 127.51, 127.32, 114.91, 111.75, 77.19, 67.50 ppm. IR v 3257, 2956, 2920, 2885, 2858, 1649, 1486, 1473, 1448, 1415, 1393, 1367, 1280, 1152, 1077, 1054, 1023, 931, 883, 746, 701 cm -1 . α! 589 =-99.7° (c 1.008, CHCl 3 ).
Analysis Calculated for C 13 H 13 NO 2 : C: 72.54; H: 6.09; N: 6.51 Found: C: 72.57; H: 6.34; N: 6.51.
EXAMPLE 26 ##STR47##
A solution of t-butyl(bromozinc)acetate from Example 2 in N-methylpyrrolidinone (43 mL of a 1.36M solution; 58.07 mmol) was charged to a 250 mL 3-neck flask under nitrogen. Overhead mechanical stirring and a cooling bath with automated temperature control were put in place. The solution was cooled to -5° C. A solution of the imine from Example 25 (5.00 g; 23.23 mmol) in NMP (40 mL) was added via addition funnel. After stirring for 3.5 hours the mixture was quenched by addition of 2N hydrochloric acid (30 mL) and saturated aqueous ammonium chloride solution (60 mL). The mixture was extracted with MTBE (2×100 mL). The combined extracts were washed with ammonium chloride solution (50 mL), water (50 mL) and sodium chloride solution (50 mL). The solution was dried (Na 2 SO 4 ) and the solvent was removed under vacuum. The crude product (yellow oil, 7.3 g) was purified by column chromatography on silica, eluting with heptane/MTBE (2:1) to yield the desired product (5.43 g; 70.5%).
1 H NMR (400 MHz, CDCl 3 ) δ(ppm): 7.29-7.19 (m, 6H), 6.21 (dd, J=3.2, 1.8 Hz, 1H), 6.07 (d, J=3.2 Hz, 1H), 4.25 (dd, J=7.7, 6.2 Hz, 1H), 3.79-3.75 (m, 2H), 3.55 (dd, J=12.0, 7.9 Hz, 1H), 2.71-2.65 (m, 2H), 1.44 (s, 9H). 13 C NMR (CDCl 3 ) δ(ppm): 170.96, 155.28, 141.62, 141.44, 128.43, 127.39, 127.08, 109.94, 106.29, 81.01, 66.09, 61.69, 51.41, 40.74, 28.03. IR v 3427, 2974, 2929, 2870, 1720, 1452, 1365, 1147 cm -1 . α! 589 =7.6° (c 0.983, CHCl 3 ).
EXAMPLE 27 ##STR48##
The aminoalcohol from Example 26 (4.88 g; 14.72 mmol) was dissolved in ethanol (30 mL) in a 100 mL 3-neck flask with magnetic stirring under nitrogen. Methylamine (1.30 mL of a 40% aqueous solution; 15.1 mmol) was added via syringe. A solution of sodium periodate (3.55 g; 16.6 mmol) in water (24 mL) at 30° C. was added in portions. Ice cooling was employed to keep the reaction temperature below 30° C. The reaction mixture was stirred for 2 hours at 25° C. then cooled to 0° C., The mixture was filtered through a glass frit washing with MTBE (100 mL). The filtrate was washed with water (50 mL) and sodium chloride solution (50 mL). The combined aqueous phases were extracted with MTBE (50 mL). The extract was washed with sodium chloride solution (30 mL). The combined organic phases were dried (Na 2 SO 4 ) and the solvent was removed under vacuum to yield a crude orange oil (4.10 g). This was dissolved in THF (10 mL) and added to p-toluenesulfonic acid (2.35 g; 12.33 mmol) at 0° C. with stirring. Heptane (25 mL) was added causing some material to oil out of solution. Further heptane (25 mL) was added and stirring continued until the material solidified. The material was broken up, collected by filtration, washed with heptane/THF (3:1, 20 mL) to yield a pale yellow solid (4.39 g; 78%).
1 H NMR (400 MHz, CDCl 3 ) δ(ppm): 8.23 (br, s, 3H), 7.67 (d, J=8.1 Hz, 2H), 7.23-7.22 (m, 1H), 7.12 (d, J=8.0 Hz, 2H), 6.40 (d, J=3.4 Hz, 1H), 6.22 (dd, J=3.3, 1.8 Hz, 1H), 4.72 (br, m, 1H), 2.96 (n, 2H), 2.35 (s, 3H), 1.32 (s, 9H). 13 C NMR (CDCl 3 ) δ(ppm): 168.80, 148.60, 142.89, 141.45, 140.24, 128.80, 126.03, 110.60, 109.47, 81.74, 45.67, 36.77, 27.83, 21.31.
Analysis Calculated for C 18 H 25 NO 6 S.1/2H 2 O: C: 55.09; H: 6.42; N: 3.57 Found: C: 55.08; H: 6.69; N: 3.83. | The invention herein is directed to a process for the preparation of ethyl 3S-amino-4-pentynoate which involves treating 3-(trimethylsilyl)-2-propynal with L-phenylglycinol in toluene to produce aS- 3-(trimethylsilyl)-2-propynylidene amino!benzenethanol; reacting aS- 3-(trimethylsilyl)-2-propynylidene!amino!benzenethanol with BrZnCH 2 CO 2 t-Bu in THF/NMP to produce 1,1-dimethylethyl 3S- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate; reacting the 1,1-dimethylethyl 3S- (2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate with sodium periodate to form 1,1-dimethylethyl 3S- (phenylmethylene)amino!-5-(trimethylsilyl)-4-pentynoate; hydrolyzing 1,1-dimethylethyl 3S- (phenylmethylene)amino!-5-(trimethylsilyl)-4-pentynoate to produce 1,1-dimethylethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate; transesterifying 1,1-dimethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate and desilylating to produce ethyl 3S-amino-4-pentynoate. |
FIELD OF INVENTION
This invention concerns a wiring harness with audio phones by which sound may be overlaid on the sound track of a video recording.
BACKGROUND TO THE INVENTION
With the advent of the compact video camera, the home recording on video of family scenes has become common. A large part of contemporary video recorders are provided with sound recording systems which lays down a sound track on the video tape itself.
Sound for the sound track is recorded through a microphone, usually mounted on the camera as a built-in feature. This microphone picks up ambient sounds from the scene being video taped.
On many occasions, the sound track may lack interest. It may constitute the shuffling of an audience in a church, waiting for a wedding to commence. Or it may constitute an inarticulate mixture of many persons over-talking each other. In such cases, it would be desirable to provide convenient means to add to the sound-track an overlay of background music.
This invention, therefore, has such an objective, and aspires to meet that objective with an arrangement that is convenient for home video users, and does not entail elaborate post-filming sound transfer activities.
SUMMARY OF THE INVENTION
According to the invention a wiring harness is provided which is adapted to couple the output of a portable audio playback machine to a miniature audio speaker that is provided with attachment means to permit the speaker to be mounted adjacent the microphone pick-up of a video camera with sound-track.
In a more elaborate combination of the invention an off-on switch is associated with such harness and audio playback machine so as to enable a user to turn the audio playback machine "on" or "off" without removing his hands from the camera. This feature may function by operating a remote controlled on-off switch on the playback machine that is already built-in such machine; or the playback machine, if battery powered, may be rendered responsive to a hand-held off-on switch by terminating the connecting wire pair from such switch to the machine to two conductive plates, separated by an insulative plate, to form an assembly that is placed between the battery of the playback machine, and the adjacent battery, or battery-connecting terminal, of that machine.
The audio playback machine may conveniently have a clip that allows it to be hung on a wearer's belt. Typically, a standard audio cassette player may be used. A suitable tape for background music is loaded and set to the beginning of the desired musical passage. The miniature audio speaker is attached to the video-camera microphone, and the user then holds the off-on switch in his hands, simultaneously with holding the video camera. For convenience, the microphone and switch may terminate in a plug into which the balance of the harness may be removably coupled.
The wiring harness may be provided with a splitter that provides a signal to an earphone worn by the operator. This earphone may also be removably coupled to the harness through a plug and jack. However, preferably the operator may connect an earphone to an already-provided output jack on the video camera that allows him to monitor the actual sound being recorded on the video sound track, if such an output is available.
The audio cassette playback sound level is set manually by a test running, with the video camera "off". The cassette is then returned to its starting position.
When the operator desires to commence video recording with sound, he manually triggers both the video camera and the audio player. This can conveniently be done by reason of the feature of the wiring harness which permits the off-on control switch of the invention to be proximate to the video camera. These two devices should preferably be started at the same time. This may particularly be arranged by using as the on-off switch a compression-activated switch that is fastened, as by gluing or by providing the on-off switch with as adhesive pad as an attachment means, on the trigger switch of the video camera.
By selecting appropriate background music, set at a modest level, an entire video scene may be shot with background music immediately in place on the video soundtrack.
Because the miniature audio speaker that provides the background sound is attached directly to the microphone, the level of sound required is low and is relatively unobtrusive. The risk of intrusive noise being generated may be further reduced by placing an insulative sound hood over the miniature speaker.
Because the sound is being provided to the microphone no rewiring of the camera, nor is any interference with its electronic circuits required.
The wiring harness of the invention is inexpensive to produce, and convenient to install. The advantages, in terms of the cost-to-benefit ratio, are substantial.
These, and further features of the invention, will be better understood from the description of the preferred embodiment which now follows.
SUMMARY OF THE DRAWINGS
FIG. 1 is a schematic of a wiring harness incorporating the basic feature of the invention.
FIG. 2 shows a further alternate wiring harness.
FIG. 3 shows a further alternate wiring harness.
FIG. 4 shows the harness installed between a video camera and an audio player.
FIG. 5 shows a means of controlling an audio player between "on" and "off" when a remote control port for this function is not provided.
FIG. 6 shows the controlling means of FIG. 4 installed adjacent to a battery.
FIG. 7 shows a double speaker arrangement.
FIG. 8 shows a single speaker arrangement.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 a plug 1 is attached to a pair of wires 2a, b running to a miniature speaker 3. This speaker 3 may be the earpiece of a conventional miniaturized audio headphone.
The plug 1 is intended for insertion into the audio output jack of an audio playback device 9, as shown in FIG. 4. This plug 1 thereby serves as a coupling means for receiving an audio-equivalent electrical signal from an audio source.
The speaker 3 is attached to a clip 4. This clip 4 is intended to grasp the speaker to the microphone 16 pick-up on a video camera 7, a shown in FIG. 4. With wires 2a, b going directly to the speaker 3, these features alone will allow a background sound-track to be laid-down on a video cassette.
It is convenient to provide an on-off control for the audio player, in conjunction with the wiring harness. This is shown in FIG. 2 wherein conjunction with the wire pair 2a, b a second wire pair 6 is run from an on-off control plug 20 to the switches. The on-off control pug 20 is intended for coupling with the remote on-off control port 10 typically found on many audio cassette players (as depicted in FIG. 4). This plug 20 thus constitutes a coupling means for controlling the on-off state of the audio source.
The wire pair 6 is of a length and is attached to the basic wire pair 2a, b at a point 21 proximate to the speaker 3 by adhesive tape 22a, or other means, so that it may be proximate to the hands of a person holding a video camera 7. This is shown in FIG. 4 where the entire harness is shown extending between the camera and the audio playback device.
The switch 5 should preferably toggle between "on" and "off" positions. It may conveniently be of the compression type and may also be provided with adhesive means 8 for fixing it to the video camera 7. Alternately, the operator may simply hold the switch 5 against the camera 7.
As a further optional arrangement, an earphone 18 may be wired in parallel to the audio feed wires 2a, b. This earphone 18 will allow the operator to monitor the sound being introduced into the microphone 16. If the video camera has its own audio jack, the operator may monitor the sound mix as it is being recorded.
The combined wiring harness may be broken into segments by a series of plugs 22, 23, 24 and jacks 22a, 23a, 24a as shown in FIG. 3. The jacks 22a, 23a, 24a, may optionally be contained in a single box 25, and be mounted on the camera. This allows the camera to be stored without the full wiring harness, while permitting quick attachment at the time of use.
In FIG. 4 an audio playback device 9 is shown which has a pre-built off-on remote control port 10. If this element is not present on the audio player 9, then a simple control system may be based on the features shown in FIG. 4.
In FIG. 5 the wires 6a, b terminate in small plates 11a, b. These may be of brass or another conductive material. The plates 11a, b, are separated by an insulative disc 12, to which they are attached on opposite sides. This assembly 15 provides a means of interrupting current flow from a battery 13, into a battery terminal 14 on the player 9. To effect such an interruption, the assembly 15 is slid between the battery 13 and one of its terminals 14,14a or between two batteries that are in series. Once this is done the player 9 will turn off and on in accordance with the switch 5 by reason of the interruption to the battery circuit made possible by the insertion of the assembly 15 in series with the battery circuit.
The speaker 3 is provided with an attachment means 4 to hold it against the video camera microphone 16. It may also be provided with a supplementary sound cover 17 of sponge or the like to reduce the level of sound being projected outwardly. This is shown in FIG. 8.
While a single speaker 3 has been shown, it is permissible to substitute a speaker pair, such as shown in FIG. 7. In this case the clip 4a embraces both speakers 3a, 3b, and permits them to be held symmetrically to the microphone. Such an arrangement is suitable when a stereo audio player is used.
On the basis of the foregoing it will be seen that a simple and convenient arrangement may be provided for adding background music to the sound-track of a video recording.
The foregoing has been a description of several preferred, exemplary embodiments of the invention. The invention in its broadest and more particular aspects is further described and defined in the claims which now follow. | A wiring harness is provided with a miniature speaker and attachment means for connecting the speaker to the microphone on a video camera. The harness is also provided with a plug for coupling the speaker to an audio play-back machine. In this manner a background of music may be laid down on the sound track of home-videos by direct audio input through the microphone pick-up on the video camera. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure for transmitting the power of an engine in a motorcycle or the like and, in particular, to the structure in which an intermediate shaft is interposed between a crankshaft and the main input shaft of a transmission. The invention also relates to a process for assembling said structure.
2. Description of Background Art
A structure for transmitting the power of an engine using such an intermediate shaft is already publicly known and, for example, Japanese Examined Patent Publication No. 7-54134 discloses a structure in which an intermediate shaft driven gear and an intermediate shaft driving gear are disposed on an intermediate shaft and in which the intermediate shaft driven gear is engaged with the driving gear of a crankshaft inside a crankcase, and in which the intermediate driving gear is engaged with the input gear of the input shaft of a transmission outside the crankshaft, and in which a balancer weight is integrally formed inside the crankcase of the intermediate shaft.
Further, Japanese Examined Patent Publication No. 7-94859 discloses a power transmission structure in which an idle gear is arranged at the end portion projecting outside the crankcase of an intermediate shaft, and is engaged with both the driving gear of a crankshaft and the input gear of the input shaft of a transmission, which are disposed outside the crankcase.
In this connection, when an intermediate shaft driven gear and a intermediate shaft driving gear are disposed on an intermediate shaft inside and outside the crankcase, as disclosed in Japanese Examined Patent Publication No. 7-54134, many man hours are required for assembly. Thus, it would be desirable to improve workability of assembly. Further, if a balancer weight is mounted on the intermediate shaft inside the crankcase, restrictions are introduced into the layout, depending on the presence or absence of a clearance between the balancer web and a crank web. Therefore, it would be desirable to provide an improved structure capable of increasing the layout flexibility and of producing a greater balancing effect.
Further, if a gear disposed on the intermediate shaft is used only as an idle gear, as Japanese Examined Patent Publication No. 7-94859 discloses, a free speed reduction ratio cannot be obtained and the distance between the intermediate shaft and the input shaft of the transmission is inevitably made greater.
The object of the present invention is to solve these problems.
SUMMARY AND OBJECTS OF THE INVENTION
In order to solve the problem described above, a first element of the present invention comprises a crankshaft, an intermediate shaft, an input shaft of a transmission, and an output shaft of the transmission, wherein these respective shafts are supported by a crankcase, characterized in that an intermediate shaft driven gear and an intermediate shaft driving gear are mounted adjacently in the axial direction on a right end of the intermediate shaft at a location outside the crankcase, and that the intermediate shaft driven gear is engaged with the driving gear of the crankshaft, and that the intermediate shaft driving gear is similarly engaged with an input gear of the input shaft of the transmission, also in a position outside the crankcase.
The present invention is also characterized in that at least one balancer weight is mounted on the left end of the intermediate shaft, which projects outside the crankcase.
In addition, the present invention is characterized in that a sub-gear having the same diameter as the intermediate shaft driven gear is overlaid on the intermediate shaft driven gear, and that a spring for turning both the gears in the opposite direction is disposed between both the gears to form a canceling structure. The intermediate shaft driving gear is also formed in the canceling structure, and has a sub-gear similar to the sub-gear of the intermediate driven gear. All four of these gears are butted together and held in place by a washer and nut, fixing all of these gears in a thrust direction.
In the present invention, the intermediate shaft driven gear and the intermediate shaft driving gear are disposed on the intermediate shaft outside the crankcase. Therefore, it is possible to mount all of the shafts, namely the crankshaft, the intermediate shaft, the main input shaft of the transmission, and the output shaft of the transmission, on the crankcase, and then to easily mount all of the gears for transmitting the power from one of these shafts to another at positions outside the crankcase. This configuration results in improved in workability of assembly of the members involved. Further, since the intermediate shaft driven gear and the intermediate shaft driving gear are mounted on the intermediate shaft in two steps, it is possible to freely set a speed reduction ratio. Moreover, the configuration of this invention shortens the distance between the intermediate shaft and the crankshaft, and the distance between the intermediate shaft and the input shaft of the transmission.
In the present invention, since the balancer weight is disposed on the intermediate shaft at the portion projecting outside the crankcase, unlike conventional embodiments in which the balancer weight is disposed inside the crankcase, the balancer weight can be mounted without regard for the clearance between itself and a crank web, thereby increasing layout flexibility. In addition, since the balancer weight is mounted at the position away from the center of the engine, it is possible to produce a greater effect for regulating lateral vibrations.
In the present invention, each of the intermediate shaft driven gear and the intermediate shaft driving gear is formed in a canceling structure, with each gear having a sub-gear. All four of these gears are then butted together and fixed in the thrust direction by means of a simple washer and nut, eliminating the need for a special fixing structure, and hence simplifying the structure.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1 is a partially cutaway view of an engine in accordance with the first preferred embodiment; and
FIG. 2 is a cross-sectional view to show a part projecting from a right case of an intermediate shaft in accordance with the second preferred embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A first embodiment will be described in the following on the basis of FIG. 1, which shows a partially cutaway view of an engine to show a structure for transmitting the power of a V-shaped engine for a motorcycle. In FIG. 1, a V-shaped engine 1 is provided and includes a piston 2 , a connecting rod 3 , a crankshaft 5 , and a crank web 6 . On the one end of the crankshaft 5 is mounted a generator 7 and on the other end thereof are mounted a primary gear 8 and a primary damper 9 which is a torque damper.
The crankshaft 5 is supported by a left case 10 and a right case 11 which constitute a crankcase. A reference numeral 12 designates a left case cover and a reference numeral 13 designates a right case cover. An intermediate shaft 20 is disposed in parallel to the crankshaft 5 , and an intermediate shaft driven gear 21 engaging with the primary gear 8 is mounted on the end portion of the intermediate shaft 20 projecting outside the right case 11 and an intermediate driving gear 22 having a diameter smaller than the intermediate shaft driven gear 21 is mounted adjacently thereto in two steps in the axial direction.
Further, a balancer weight 23 is mounted on the other end portion of the intermediate shaft 20 projecting outside the left case 10 . The balancer weight 23 is constituted as a primary balancer for reducing the coupling vibrations (lateral vibrations caused by couple of forces) of the crankshaft 5 .
Further, a main shaft 30 , which is the input shaft of a transmission, and a counter shaft 31 , which is the output shaft of the transmission, are mounted in parallel to the intermediate shaft 20 . A clutch 32 is mounted on the portion of the main shaft 30 projecting outside the right case 11 and a primary driven gear 33 connected to the outer side of the clutch 32 is engaged with the intermediate shaft driving gear 22 . The inner side of the clutch 32 is connected to the main gear train 34 on the main shaft 30 , and power is intermittently transmitted from the primary driven gear 33 , which is the input gear, to the main gear train 34 by the intermittent engagement of the clutch 32 .
The main gear train 34 is always engaged with the counter gear train 35 on the counter shaft 31 and when a speed change operation is selected by means of a publicly known shift mechanism, a variable speed is applied to a bevel gear 36 , which is an output gear, mounted on the one end of the counter shaft 31 . The bevel gear 36 is engaged with a bevel bear 38 of an output shaft 37 connected to a driving shaft (not shown) to drive a driving wheel such as a rear wheel or the like by a shaft driving operation.
Next, the action of the present preferred embodiment will be described. The intermediate shaft driven gear 21 and the intermediate shaft driving gear 22 are mounted adjacently to each other in the axial direction on the intermediate shaft 20 at the portion of projecting outside the right case 11 . Therefore, when assembling this engine, first, the shafts ( 5 , 20 , 30 , 31 ) are assembled between the left case 10 and the right case 11 so that they support both the cases 10 , 11 . Then, the primary gear 8 and the primary damper 9 are mounted on the crankshaft 5 outside the right case 11 , and the intermediate shaft driven gear 21 and the intermediate driving gear 22 are mounted on the intermediate shaft 20 , and the clutch 32 is mounted on the main shaft 30 , and the intermediate shaft driven gear 21 is engaged with the primary gear 8 and the intermediate shaft driving gear 22 is engaged with the primary driven gear 33 of the clutch 32 .
In this manner, a gear train for transmitting power between the crankshaft 5 , the intermediate shaft 20 and the main shaft 30 outside the right case 11 can be assembled outside the right case 11 in a state where each of the shafts are positioned with respect to the crankcase. This can improve workability in assembling them. Further, since the intermediate shaft driven gear 21 and the intermediate shaft driving gear 22 are mounted in two steps, a speed reduction ratio can be freely set, and further, the distance between the intermediate shaft 20 and the crankshaft 5 and the distance between the intermediate shaft 20 and the main shaft 30 can be made smaller. Still further, since the intermediate shaft driven gear 21 having a larger diameter, is mounted at the crank room side, which is the inner side, and an intermediate shaft driving gear 22 having a smaller diameter, is mounted at the outer side thereof, there is not the possibility that the larger intermediate shaft driven gear 21 will interfere with the clutch 32 disposed on the main shaft 30 .
Further, since the balancer weight 23 is mounted on the intermediate shaft 20 at the other end side projecting outside the left case 10 , unlike inventions described in prior art where the balancer weight 23 is typically mounted inside the left case 10 and a balancer weight 23 and the crank web 6 . Thus, the present invention increases the flexibility in the layout. Still further, since the balancer weight 23 is mounted on the side opposite to the side of the intermediate shaft 20 where the intermediate shaft driven gear 21 and the intermediate shaft driving gear 22 are mounted, the flexibility in the layout of the balancer weight 23 can be further increased. Still further, since the balancer weight 23 is mounted on the intermediate shaft 20 at the position farthest from the center of the engine, the distance from the center to the balancer weight 23 is made greater, resulting in a greater balancing effect for regulating lateral vibrations.
Next, a second embodiment of the present invention will be described on the basis of FIG. 2 . In this connection, FIG. 2 is a cross-sectional view to show a portion of the intermediate shaft 20 projecting outside the right case 11 , and like reference numerals are used for the parts common to those in the first preferred embodiment, and thus will be omitted. In this second embodiment, each of the intermediate shaft driven gear 21 and the intermediate shaft driving gear 22 is formed in a canceling structure. That is, a sub-gear 51 having an equivalent diameter and a narrower width with respect to the intermediate shaft driven gear 21 , which is a main gear, is overlaid on the driven gear 21 , and both the gears 51 and 21 are turned and urged in the direction opposite to each other by a coil spring 53 between both the gears 21 and 51 . The intermediate shaft driven gear 21 is spline-coupled with the intermediate shaft 20 by the spline grooves 20 a and is engaged with the primary gear 8 along with the sub-gear 51 . The sub-gear 51 is fitted on the boss 54 of the intermediate shaft driven gear 21 such that it can turn with a play.
Further, the intermediate shaft driving gear 22 is also formed in the canceling structure and has a coil spring 55 disposed between intermediate shaft driving gear and the sub-gear 52 . The sub-gear has an equivalent diameter and a narrower width with respect to the intermediate driving gear 22 , and the sub-gear 52 is engaged with the primary driven gear 33 along with the intermediate shaft driving gear 22 . The intermediate shaft driving gear 22 is spline-coupled with the intermediate shaft 20 by the spline grooves 20 a and is fitted on the boss 56 of the intermediate shaft driving gear 22 such that it can turn with a play.
When assembling these gears, first, the intermediate shaft driven gear 21 is fitted on and spline-coupled with the intermediate shaft 20 and then the sub-gear 51 is fitted on the boss 54 of the intermediate shaft driven gear 21 with the coil spring 53 disposed on the side opposed to the sub-gear 51 to support the coil spring 53 between the intermediate shaft driven gear 21 and the sub-gear 51 . Subsequently, the intermediate shaft driving gear 22 is fitted on and spline-coupled with the intermediate shaft 20 , and then the sub-gear 52 is fitted on the boss 56 of the intermediate shaft driving gear 22 . Here, the coil spring 55 is previously sandwiched between the intermediate shaft driving gear 22 and the sub-gear 52 .
Thereafter, a nut 58 is fastened to the shaft end of the intermediate shaft 20 via a washer 57 to fix these four gears 21 , 51 , 22 , and 52 in the thrust direction. Here, the sub-gear 51 is butted against and positioned by the side surfaces of the intermediate shaft driven gear 21 and the intermediate shaft driving gear 22 . Therefore, since the sub-gear 51 can be positioned in the thrust direction by fixing the neighboring intermediate shaft driving gear 22 without using a special member, it is possible to reduce the number of the parts and to simplify the structure.
In this connection, the present invention is not limited to the preferred embodiments described above, and various modifications may be made within the spirit and scope of the present invention and, for example, a publicly type of continuously variable transmission can be adopted as the structure of the transmission.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | A structure for transmitting the power of a motorcycle engine includes an intermediate shaft arranged between a crankshaft and an input shaft of a transmission, and a method for making the structure. The structure and the method have the objective of shortening the distances between these three shafts, improving workability of assembling, and providing freedom of setting a speed reduction ratio. An intermediate shaft driven gear and an intermediate shaft driving gear having a diameter smaller than the intermediate shaft driven gear and are mounted in two steps, with the former overlaid on the latter, on an end of the intermediate shaft projecting outside a right case. Similarly, the intermediate shaft driven gear is engaged with a primary gear of the crankshaft, and the intermediate shaft driving gear is engaged with a primary driven gear of the input shaft at a location outside the right case. |
FIELD OF THE INVENTION
The present invention relates generally to the database management field, and more particularly, relates to a method, apparatus and computer program product for implementing enhanced query governor functions.
DESCRIPTION OF THE RELATED ART
Databases are computerized information storage and retrieval systems. Databases are managed by systems and may take the form of relational databases and hierarchical databases. A Relational Database Management System (RDBMS) is a database system that uses relational techniques for storing and retrieving data. Relational databases are organized into tables consisting of rows (tuples) and columns of data. A relational database typically includes many tables, and each table includes multiple rows and columns. The tables are conventionally stored in direct access storage devices (DASD), such as magnetic or optical disk drives, for semi-permanent storage.
Relational Database Management System (RDBMS) software using a Structured Query Language (SQL) interface is well known in the art. The SQL interface has evolved into a standard language for RDBMS software and has been adopted as such by both the American Nationals Standard Organization (ANSI) and the International Standards Organization (ISO).
A database management system (DBMS) typically includes some form of query governor. Known query governors typically enable a database administrator and user of the database to have queries time out if the queries take too long. In this case queries are prevented from taking up too much system resources.
Current technology simply allows the database user to time out a query based upon execution time but does take into account multiple aspects or the breakdown of a query into executing components.
A need exists for a mechanism to enable the database user to be allowed to modify multiple query attributes including multiple executing components of a query. It is desirable that a query can be broken down into multiple query execution components, for example, data retrieval, trigger processing, and user defined function (UDF) processing, and with each of these query execution components having an individual time out value.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide a method, apparatus and computer program product for implementing enhanced query governor functions. Other important objects of the present invention are to provide such method, apparatus and computer program product for implementing enhanced query governor functions substantially without negative effect and that overcome many of the disadvantages of prior art arrangements.
In brief, a method, apparatus and computer program product are provided for implementing enhanced query governor functions. Query execution includes first checking for a timeout value for a query. Responsive to identifying a timeout value for the query, an execution time for the query is reset and a monitor for each timeout value for the query is started. Then the execution of the query is started. The execution of predefined events is monitored during the execution of the query. The predefined events include a begin or end of processing of at least one of a trigger and a user defined function (UDF). Execution status of the query is periodically checked. Responsive to identifying the query is executing, checking for any expired timeout value is performed. The execution of the query is halted responsive to an identified expired timeout value.
In accordance with features of the invention, empirical data for trigger processing and UDF processing is used to determine whether in most likelihood that the query can finish within set timeout values for the trigger and user defined function (UDF), and execution of the query is started only responsive to determining in most likelihood the query can finish within the timeout values.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention together with the above and other objects and advantages may best be understood from the following detailed description of the preferred embodiments of the invention illustrated in the drawings, wherein:
FIG. 1 is a block diagram illustrating a computer system for implementing methods for processing enhanced query governor functions in accordance with the preferred embodiment;
FIGS. 2 , 3 , 4 , and 5 are flow charts illustrating exemplary steps performed by the computer system of FIG. 1 for implementing enhanced query governor functions in accordance with the preferred embodiment;
FIG. 6 is a diagram illustrating an exemplary data table for storing UDF and trigger data in accordance with the preferred embodiment; and
FIG. 7 is a block diagram illustrating a computer program product in accordance with the preferred embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, in FIG. 1 there is shown a computer system generally designated by the reference character 100 for implementing methods for processing enhanced query governor functions in accordance with the preferred embodiment. Computer system 100 includes a processor 102 coupled to a memory 104 . Computer system 100 includes a mass storage 106 , such as a direct access storage device (DASD), a display 108 , and a user input 110 coupled to the processor 102 .
Computer system includes an operating system 112 , a database management system 114 including a query optimizer 116 and a query object 118 . The query object 118 includes a number of methods or plans capable of performing specific operations relevant to management of the query object and the execution of a query represented by such an object. Database management system 114 includes a query governor program 120 of the preferred embodiment including a SQL processor program 122 and a user defined function (UDF) and trigger monitor program 124 , and a UDF and trigger data table 126 . Computer system includes a database 130 stored in the mass storage 106 , and a local area network (LAN) or wide area network (WAN) 132 that couples I/O devices 134 , such as personal computers to the computer system 100 . Computer system 100 is shown in simplified form sufficient for an understanding of the present invention.
In accordance with features of the preferred embodiment, query governor program 120 of the preferred embodiment includes the SQL processor program 122 and UDF and trigger monitor program 124 . The query governor programs 120 , 122 , 124 enable the database administrator and users of the database to modify query attributes and to monitor and maintain empirical data for implementing enhanced query governor functions of the preferred embodiment. With the query governor programs 120 , 122 , 124 , the components of a query are broken down into query execution, i.e., data retrieval, trigger processing, and user defined function (UDF) processing. The database user is allowed to break down a query into multiple executing components or individual pieces, each with individual time out values. Empirical data for multiple query attributes, such as how long UDFs and triggers take to execute, is maintained in accordance with features of the preferred embodiment.
Advantages are provided by the enhanced query governor functions of the preferred embodiment. For example, the database administrator or user is enabled to modify query attributes, such as turning off certain trigger processing and changing a web service UDF.
It should be understood that the present invention is not limited for use with the illustrated computer system 100 . The illustrated processor system 100 is not intended to imply architectural or functional limitations. The present invention can be used with various hardware implementations and systems and various other internal hardware devices, for example, multiple main processors.
Various commercially available processors could be used for computer system 100 , for example, an AS/400 or iSeries computer system manufactured and sold by International Business Machines Corporation.
Referring to FIGS. 2 , 3 , 4 , and 5 there are shown exemplary steps performed by the computer system 100 for implementing methods for processing enhanced query governor functions in accordance with the preferred embodiment. The query governor program 120 including SQL processor program 122 and UDF and trigger monitor program 124 of the preferred embodiment perform the exemplary steps for processing enhanced query governor functions in accordance with the preferred embodiment.
Referring first to FIG. 2 , there are shown exemplary steps of the SQL processor program 122 starting at a block 200 for handling SQL events. First, waiting for an event is provided as indicated in a block 202 . When an event is received, checking to determine if the received event is to modify query attributes as indicated in a decision block 204 . If so, then a modify attributes routine is performed as indicated in a block 206 . The modify attributes routine is illustrated and described with respect to FIG. 4 . Otherwise, if the received event is not to modify query attributes, checking whether the event is an event to execute a query is performed as indicated in a decision block 208 . If so, then an execute query routine is performed as indicated in a block 210 . The execute query routine is illustrated and described with respect to FIG. 3 . Otherwise, if not an event to execute a query, then any other known SQL event known in the art is processed as indicated in a block 212 . Then the sequential operations return to block 202 to wait for another event.
Referring now to FIG. 3 , there are shown exemplary steps of the execute query routine starting at a block 300 for handling execution of queries. Before starting to process the query, checking to determine if any timeouts exist for this query is performed as indicated in a decision block 301 . Any timeouts for this query are set through changing the query attributes using the modify attributes routine of FIG. 4 . If no timeouts exist, then the query is executed as known in the art as indicated in a block 302 . If a timeout exists, then checking to determine based on empirical data whether in most likelihood that the query can finish within the timeout values is performed as indicated in a decision block 303 . If in most likelihood the query will not finish within the timeout values, then the query is not even started and the sequential steps end or exit as indicated in a block 304 . Otherwise if determined that the query can finish within the timeout values, then the execution time is reset for each timeout as indicated in a block 306 and monitors are set as indicated in a block 308 . A monitor in this case is one that will track processing time of a user defined function (UDF) and/or a trigger. The monitor or monitors track the timeout values previously set.
Then the execution of the query is started as indicated in a block 310 . After starting the execution of the query in a separate thread, this main thread then waits a predetermined period of time as indicated in a block 312 . This predetermined period of time or time value is a sub-factor of the timeout value. This means if a limit of 10 seconds is set for UDF processing, then the predetermined period of time for the wait limit will be a division of 10 seconds, such that a wake up is set for checking if the query is still executing as indicated in a decision block 314 . If the query is not executing, then the sequential steps end or exit as indicated in a block 316 because the query is done executing. Otherwise, checking whether the time limit has expired is performed as indicated in a decision block 318 . If any of the timeouts has been reached, then execution of the query is halted as indicated in a block 320 and a return code is set as indicated in a block 322 . Then the sequential steps end or exit as indicated in a block 324 . Otherwise if no time limit has expired at decision block 318 , then the sequential steps return to block 312 to wait for the predetermined period of time.
Referring now to FIG. 4 , there are shown exemplary steps of the modify attributes routine starting at a block 400 to set query attributes. First checking to determine if a monitor is being requested is performed as indicated in a decision block 402 . If so, then the monitor is set for a timeout as indicated in a block 404 . Then as indicated in a block 406 , the rest of the query attributes are changed as known in the art. Then the sequential steps end or exit as indicated in a block 408 . Otherwise if a monitor is not being requested, then the rest of the query attributes are changed as known in the art at block 406 and the sequential steps exit at block 408 .
As described with respect to block 406 in FIG. 4 , enhanced query governor functionality is being added to the known or existing art of changing query attributes. Changing query attributes generally allows for various other query functionalities; that-is used in accordance with features of the preferred embodiment to set timeout values for UDF processing and trigger processing.
Referring now to FIG. 5 , there are shown exemplary steps of the UDF and trigger monitor program 124 starting at a block 500 for monitoring the execution of each UDF and each trigger such that empirical data can be maintained on how long the UDFs and triggers take to execute. First, waiting for an event is provided as indicated in a block 502 . When an event is received, checking to determine if the received event is a trigger event begin or end as indicated in a decision block 504 . If so, then the trigger event and start or stop time is recorded as indicated in a block 506 . Otherwise when the received event is not a trigger event, checking to determine if the received event is a UDF event begin or end as indicated in a decision block 508 . If so, then the UDF event and start or stop time is recorded as indicated in a block 510 . Otherwise, if not a trigger or UDF event begin or end, then any other known SQL event known in the art is processed as indicated in a block 512 . Then the sequential operations return to block 502 to wait for another event.
Referring now to FIG. 6 , there is shown an exemplary data table 126 for storing UDF and trigger data in accordance with the preferred embodiment. The UDF and trigger data table 126 stores a start time 602 , a stop time 604 , and an event 606 , either a UDF event or a trigger event. The UDF and trigger data table 126 contains the start and stop times 602 , 604 for UDFs and triggers 606 that is kept up to date by the processing performed as shown in the flow chart of FIG. 5 .
Referring now to FIG. 7 , an article of manufacture or a computer program product 700 of the invention is illustrated. The computer program product 700 includes a recording medium 702 , such as, a floppy disk, a high capacity read only memory in the form of an optically read compact disk or CD-ROM, a tape, a transmission type media such as a digital or analog communications link, or a similar computer program product. Recording medium 702 stores program means 704 , 706 , 708 , 710 on the medium 702 for carrying out the methods for implementing enhanced query governor functions of the preferred embodiment in the system 100 of FIG. 1 .
A sequence of program instructions or a logical assembly of one or more interrelated modules defined by the recorded program means 704 , 706 , 708 , 710 , direct the computer system 100 for processing enhanced query governor functions of the preferred embodiment.
While the present invention has been described with reference to the details of the embodiments of the invention shown in the drawing, these details are not intended to limit the scope of the invention as claimed in the appended claims. | A method, apparatus and computer program product are provided for implementing enhanced query governor functions. Query execution includes first checking for a timeout value for a query. Responsive to identifying a timeout value for the query, an execution time for the query is reset and a monitor for each timeout value for the query is started. Then the execution of the query is started. The execution of predefined events is monitored during the execution of the query. The predefined events include a begin or end of processing of at least one of a trigger and a user defined function (UDF). Execution status of the query is periodically checked. Responsive to identifying the query is executing, checking for any expired timeout value is performed. The execution of the query is halted responsive to an identified expired timeout value. |
This application claims the benefit of U.S. Provisional Application No. 60/146,350, filed Aug. 2, 1999 (now abandoned).
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the fields of microbiology and microbial genetics. More specifically, the invention relates to novel bacterial strains, methods and processes useful for the fermentative production of amino acids.
2. Related Art
Following the recognition that Corynebacteria were useful for the fermentative production of amino acids (S. Kinoshita et al., Proceedings of the International Symposium on Enzyme Chemistry 2:464–468 (1957)), the industrial production of L-lysine became an economically important industrial process. Commercial production of this essential amino acid is principally done utilizing the gram positive Corynebacterium glutamicum, Brevibacterium flavum and Brevibacterium lactofermentum (Kleemann, A., et. al., “Amino Acids,” in U LLMANN'S E NCYCLOPEDIA OF I NDUSTRIAL C HEMISTRY , vol. A2, pp. 57–97, Weinham: VCH-Verlagsgesellschaft (1985)). These organisms presently account for the approximately 250,000 tons of L-lysine produced annually.
The efficiency of commercial production of L-lysine may be increased by the isolation of mutant bacterial strains which produce larger amounts of L-lysine. Microorganisms employed in microbial process for amino acid production are divided into 4 classes: wild-type strain, auxotrophic mutant, regulatory mutant and auxotrophic regulatory mutant (K. Nakayama et al., in Nutritional Improvement of Food and Feed Proteins , M. Friedman, ed., (1978), pp. 649–661). Mutants of Corynebacterium and related organisms inexpensive production of amino acids from cheap carbon sources, e.g., mollasses, acetic acid and ethanol, by direct fermentation. In addition, the stereospecificity of the amino acids produced by fermentation (the L isomer) makes the process advantageous compared with synthetic processes.
Given the economic importance of L-lysine production by the fermentive process, the biochemical pathway for lysine synthesis has been intensively investigated, ostensibly for the purpose of increasing the total amount of L-lysine produced and decreasing production costs (recently reviewed by Sahm et al., Ann. N.Y. Acad. Sci. 782:25–39 (1996)). Entry into the lysine pathway begins with L-aspartate (see FIG. 1 ), which itself is produced by transamination of oxaloacetate. A special feature of C. glutamicum is its ability to convert the lysine intermediate piperidine 2,6-dicarboxylate to diaminopimelate by two different routes, i.e., by reactions involving succinylated intermediates or by the single reaction of diaminopimelate dehydrogenase. Overall, carbon flux into the pathway is regulated at two points: first, through feedback inhibition of aspartate kinase by the levels of both L-threonine and L-lysine; and second through the control of the level of dihydrodipicolinate synthase. Increased production of L-lysine may be therefore obtained in Corynebacteria by deregulating and increasing the activity of these two enzymes.
In addition to the biochemical pathway leading to L-lysine synthesis, recent evidence indicates that the transportation of L-lysine out of cells into the media is another factor to be considered in the development of lysine over-producing strains of C. glutamicum . Studies by Krämer and colleagues indicate that passive transport of lysine out of the cell, as the result of a leaky membrane, is not the sole explanation for lysine efflux; their data suggest a specific carrier with the following properties: (1) the transporter possesses a rather high Km value for lysine (20 mM); (2) the transporter is an OH − symport system (uptake systems are H + antiport systems); and (3) the transporter is positively charged, and membrane potential stimulates secretion (S. Bröer and R. Krämer, Eur. J. Biochem. 202: 137–143 (1991).
Several fermentation processes utilizing various strains isolated for auxotrophic or resistance properties are known in the art for the production of L-lysine: U.S. Pat. No. 2,979,439 discloses mutants requiring homoserine (or methionine and threonine); U.S. Pat. No. 3,700,557 discloses mutants having a nutritional requirement for threonine, methionine, arginine, histidine, leucine, isoleucine, phenylalanine, cystine, or cysteine; U.S. Pat. No. 3,707,441 discloses a mutant having a resistance to a lysine analog; U.S. Pat. No. 3,687,810 discloses a mutant having both an ability to produce L-lysine and a resistance to bacitracin, penicillin G or polymyxin; U.S. Pat. No. 3,708,395 discloses mutants having a nutritional requirement for homoserine, threonine, threonine and methionine, leucine, isoleucine or mixtures thereof and a resistance to lysine, threonine, isoleucine or analogs thereof; U.S. Pat. No. 3,825,472 discloses a mutant having a resistance to a lysine analog; U.S. Pat. No. 4,169,763 discloses mutant strains of Corynebacterium that produce L-lysine and are resistant to at least one of aspartic analogs and sulfa drugs; U.S. Pat. No. 5,846,790 discloses a mutant strain able to produce L-glutamic acid and L-lysine in the absence of any biotin action-surpressing agent; and U.S. Pat. No. 5,650,304 discloses a strain belonging to the genus Corynebacterium or Brevibacterium for the production of L-lysine that is resistant to 4-N-(D-alanyl)-2,4-diamino-2,4-dideoxy-L-arabinose 2,4-dideoxy-L-arabinose or a derivative thereof.
More recent developments in the area of L-lysine fermentive production in Corynebacteria involve the use of molecular biology techniques to augment lysine production. The following examples are provided as being exemplary of the art: U.S. Pat. Nos. 4,560,654 and 5,236,831 disclose an L-lysine producing mutant strain obtained by transforming a host Corynebacterium or Brevibacterium microorganism which is sensitive to S-(2-aminoethyl)-cysteine with a recombinant DNA molecule wherein a DNA fragment conferring resistance to S-(2-aminoethyl)-cysteine and lysine producing ability is inserted into a vector DNA; U.S. Pat. No. 5,766,925 discloses a mutant strain produced by integrating a gene coding for aspartokinase, originating from Coryneform bacteria, with desensitized feedback inhibition by L-lysine and L-threonine, into chromosomal DNA of a Coryneform bacterium harboring leaky type homoserine dehydrogenase or a Coryneform bacterium deficient in homoserine dehydrogenase gene.
Many process designed utilizing bacterial mutant strains are designed to weaken bacterial growth and hence to enhance the yield of amino acid production through supplementation with other nutrients. Usually, mutants designed to improve the percent yield of an amino acid from substrates such as glucose will also lose their ability for vigorous growth like their wild type strains. Besides resulting in an overall decrease in amino acid yield, these mutants also require more nutrients to support their growth, which can increase the cost in the production significantly.
Thus, there is a continuing need in the art for the development of novel amino acid producing bacterial strains that enable maximized yields of a particular amino acid at a low cost of production. In view of these problems, an alternative method comprises special mutants and media that is employed to increase the productivity and to decrease the ingredient cost.
SUMMARY OF THE INVENTION
The invention provides generally for novel microorganisms with improved raffinate resistance and improved growth properties, which enables higher yields of amino acid to be produced.
A first object of the invention provides novel methods for the production of microorganisms with increased ability to produce amino acids. In a first embodiment of the invention, a method is provided for the production of a novel strain by way of mutagenesis of an amino acid-producing, parental bacterial strain and subsequent selection for the improved raffinate resistant strains of the invention. In a more specific embodiment of the invention, the methods are drawn to amino acid-producing, parental bacterial strains such as Corynebacterium and Brevibacterium . A particularly favored embodiment is drawn to a method for the production of an improved raffinate-resistant, amino acid producing bacterial strain that is Brevibacterium which produces L-lysine.
Another object of the invention is drawn to novel bacterial strains with improved raffinate-resistance, improved growth characteristics and that produce larger amounts of amino acid. In a first embodiment, bacterial strains of the invention are produced by a process wherein a parental bacterial strain is subjected to mutagenesis and mutant progeny bacteria are selected for improved raffinate-resistance, improved growth characteristics and improved amino acid production. A more specific embodiment is drawn to novel Corynebacterium or Brevibacterium microorganisms with improved raffinate-resistance, improved growth characteristics and improved amino acid production. Particularly favored embodiments of the invention are drawn to Brevibacterium that produce large amounts of L-lysine. Most favored embodiments are drawn to the strains ADM L63.148 (NRRL B-30059), ADM L64.132 (NRRL B-30060), ADM L69.53 (NRRL B-30061), ADM L69.74 (NRRL B-30062), and ADM L69.100 (NRRL B-30063), or mutants thereof.
A third object of the invention provides processes for the production of an amino acid comprising the steps of (a) culturing a bacterium in a raffinate containing medium and (b) recovering the amino acid from the culture media. In a preferred embodiment, the cultured bacteria of step (a) is obtained by a method in which an amino acid-producing, parental bacterial strain is subjected to mutagenesis and progeny are selected for improved raffinate-resistance, improved growth characteristics and improved production an amino acid. Favored embodiments are drawn to processes for the production of an amino acid that utilize Corynebacterium or Brevibacterium . Particularly favored embodiments of the invention for processes for the production of an amino acid utilize Brevibacterium that produce L-lysine.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 . A) A schematic presentation of the biochemical pathway leading to L-lysine production in Corynebacterium ; B) A schematic presentation of the biochemical pathway leading to L-isoleucine production in Corynebacterium.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
1. Definitions
In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided.
High Yield Derivative: As used herein, the term refers to strain of microorganism that produces a higher yield from dextrose of a specific amino acid when compared with the parental strain from which it is derived.
Mutation: As used herein, the term refers to a single base pair change, insertion or deletion in the nucleotide sequence of interest.
Operon: As used herein, the term refers to a unit of bacterial gene expression and regulation, including the structural genes and regulatory elements in DNA.
Parental Strain: As used herein, the term refers to a strain of microorganism subjected to some form of mutagenesis to yield the microorganism of the invention.
Phenotype: As used herein, the term refers to observable physical characteristics dependent upon the genetic constitution of a microorganism.
Raffinate: As used herein, the term refers to a wastestream product from an ion-exchange operation for lysine recovery. Raffinate contains a large amount of ammonia sulfate, L-lysine, other amino acids, salts, and carbohydrates such as isomaltose. Sterilization of a medium using heat treatment produces amino acid derivatives and other metabolic antagonists which cause the inhibition of culture growth.
Heat sterilized raffinate-containing medium may be used to select microorganisms, e.g., Brevibacterium or Corynebacterium , that are resistant to amino acid derivatives contained therein that inhibit culture growth; that are resistant to metabolic inhibitors contained therein that inhibit culture growth and/or that are resistant to degradation products of lysine and/or precursors to lysine contained therein that inhibit culture growth.
Relative Growth: As used herein, the term refers to a measurement providing an assessment of growth by directly comparing growth of a parental strain with that of a progeny strain over a defined time period and with a defined medium.
Mutagenesis: As used herein, the term refers to a process whereby a mutation is generated in DNA. With “random” mutatgenesis, the exact site of mutation is not predictable, occurring anywhere in the chromosome of the microorganism, and the mutation is brought about as a result of physical damage caused by agents such as radiation or chemical treatment.
2. Mutagenesis of Parental Bacterial Strains
The invention provides methods for the production of microorganisms that produce large amounts of an amino acid and have improved resistance to raffinate. Through the course of studies, it has now been found that ammonia sulfate which is required for the growth and amino acid biosynthesis may be replaced with raffinate, a wastestream product from an ion-exchange operation of lysine recovery. Raffinate contains a lot of ammonia sulfate, L-lysine, other amino acids, salts, and carbohydrates such as isomaltose. During heat treatment to sterilize the medium, however, this raffinate medium produces a lot of amino acid derivatives and other metabolic antagonists which causes the inhibition of growth for culture. To overcome this problem, a method was designed to select strains which can resist high levels of raffinate in the medium and increase their amino acid production.
Bacterial strains of the invention are preferably made by means of mutagenesis of a parental bacterial strain followed by selection of the improved raffinate-resistant phenotype. Parental microorganisms may be selected from any organism known in the art to be useful for the fermentative production of amino acids; favored parental microorganisms are Corynebacterium and Brevibacterium that produce an amino acid, and most particularly favored organisms are Corynebacterium and Brevibacterium that produce L-lysine.
In a first embodiment, the invention provides a methods for the production of improved raffinate-resistant, amino acid-producing, bacterial strains comprising:
(a) subjecting a parental bacterial strain A to mutagenesis; (b) contacting said mutagenized parental strain A with a medium containing at least about 1% raffinate based on ammonia sulfate content; (c) selecting raffinate-resistant bacterial strain B; and (d) determining L-lysine production of said raffinate-resistant bacterial strain B.
The parental strain may be mutagenized using any random mutagenesis technique known in the art, including, but not limited to, radiation and chemical procedures. Particularly preferred is random chemical mutagenesis, and most preferable is mutagenesis using a suitable agent such as N-methyl-N′-nitro-N-nitrosoguanidine (NTG).
General methods for mutagenesis and selection of novel bacterial strains are well known in the art and are described, for example, in J. H. Miller, Experiments in Molecular Genetics , Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1972); J. H. Miller, A Short Course in Bacterial Genetics , Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1992); M. Singer and P. Berg, Genes & Genomes , University Science Books, Mill Valley, Calif. (1991); J. Sambrook, E. F. Fritsch and T. Maniatis, Molecular Cloning: A Laboratory Manual, 2d ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989); P. B. Kaufman et al., Handbook of Molecular and Cellular Methods in Biology and Medicine , CRC Press, Boca Raton, Fla. (1995); Methods in Plant Molecular Biology and Biotechnology , B. R. Glick and J. E. Thompson, eds., CRC Press, Boca Raton, Fla. (1993); and P. F. Smith-Keary, Molecular Genetics of Escherichia coli , The Guilford Press, New York, N.Y. (1989).
Strains of the invention have an improved raffinate resistant phenotype, which is determined by the concentration of raffinate, as measured by ammonium sulfate content, in the selection medium employed. In a first embodiment, phenotype selection may be done in a medium containing at least about 1% raffinate. In a most preferred embodiment, microorganisms of the invention are selected in medium containing about 5% raffinate. Other examples include at least about 2%, 3%, 4%, 5%, 6%, 7%, and 8% raffinate containing medium for use in the selection of improved raffinate resistant strains.
The invention provides generally for novel microorganisms with improved raffinate resistance and improved growth properties, which enables higher yields of amino acid to be produced. An important element or property of the methods, processes or microorganisms of the invention is related to raffinate resistance.
Skilled artisans in the art of fermentative amino acid production are familiar with the term “raffinate” as used herein. However, for the purposes of more fully providing a detailed description of Applicants' invention, a definition of raffinate and a method for its production are provided.
The term “raffinate” is most closely associated with the chemical engineering field in the area of liquid—liquid extraction. The term is defined in solvent refining as “that portion of the treated liquid mixture that remains undissolved and is not removed by the selective solvent” (Dictionary of Scientific and Technical Terms, Sybil P. Parker, ed., McGraw-Hill (1989)). As used herein, the term is associated with the application of ion-exchange chromatography in the isolation of amino acids. In an analogous fashion to the process of liquid—liquid extraction, the term raffinate as used in connection with ion-exhange chromatography refers to that portion of the liquid mixture that is not selectively bound by the chromatographic resin. More specifically, in connection with the fermentative production of amino acids, the raffinate is that portion of the cell culture media that does not bind to the chromatographic column; raffinate is the broth effluent waste stream product generated during the ion-exchange chromatographic purification of an amino acid. Typically, as used herein, raffinate refers to the first waste stream product generated after the initial application of the growth media to the ion-exchange resin.
A variety of ion-exchange chromatographic methods may be utilized for the purification of amino acids. Typically, cation exchange resins are utilized for the purification of lysine. Ion-exchange chromatography may be done utilizing a fixed bed or simulated moving bed resin. For example, Van Walsern and Thompson describe a simulated moving bed technique for the isolation of lysine (Van Walsem, H. J. and Thompson, M. C., J. Biotechnology 59:127–132 (1997); U.S. Pat. Nos. 4,714,767 and 5,684,190 describe the use of a fixed bed chromatographic technique for the purification of amino acids and Wolfgang and Prior utilize an annular chromatograph to achieve a continuous mode of operation in the separation of carbohydrates (Wolfgang, J. and Prior, A., Separation Science and Technology 32:71–82 (1997)). Thus, the specific chromatographic method of generating raffinate may vary, but the underlying principle defining raffinate remains constant.
For exemplary purposes only, Applicants provide in Example 5 details for the production of raffinate for use as a cell growth medium supplement. As one skilled in the art would know, raffinate may be qualitatively characterized according to the specific amino acid produced in the fermentation medium from which the raffinate is isolated; for example, raffinate may be known as lysine-raffinate when isolated from lysine fermentation medium, glycine-raffinate when isolated from glycine fermentation medium, isoleucine-raffinate when isolated from isoleucine fermentation medium, etc. It will be readily apparent to those skilled in the art that when the general term raffinate is used herein, the specific type of raffinate selected will depend upon practitioner design.
The example provided herein is exemplary for the production of raffinate, in particular for lysine-raffinate. As will be obvious to those skilled in the art, other methods may be utilized in the generation of raffinate.
3. Improved Raffinate Resistant Strains of the Invention
Another object of the invention is drawn to microorganisms that have improved raffinate resistance and that produce an amino acid. As one skilled in the art will know, such microorganisms may selected to have improved resistance to any specific type of raffinate, for example, glycine-raffinate, valine-raffinate, isoleucine-raffinate, lysine-raffinate, etc. In a particularly preferred embodiment, the microorganisms have improved resistence to lysine-raffinate.
In a specific embodiment of the invention, the raffinate-resistant microorganisms are produced by a process wherein:
(a) a parental bacterial strain A is subjected to mutagenesis; (b) the mutagenized parental strain A is contacted with a medium containing at least about 1% raffinate based on ammonia sulfate content; (c) a raffinate-resistant bacterial strain B is selected; and (d) amino acid production of said raffinate-resistant bacterial strain B is determined.
Selection of parental bacterial strains, mutagenesis and the selection of microorganisms of the invention with improved raffinate resistance may be done as heretofore described.
A more specific embodiment of the invention is drawn to Corynebacterium or Brevibacterium ; especially favored are Corynebacterium or Brevibacterium that produce L-lysine.
The invention also provides a Corynebacterium strain producing at least about 10 g L-lysine/liter/in 24 hours when grown in a medium containing at least about 1% raffinate.
A particularly favored embodiment of the invention is drawn to an L-lysine producing Corynebacterium strain, wherein said strain is selected from the group consisting of NRRL B3059, NRRL B-30060, NRRL B-30061, NRRL B-30062, NRRL B-30063 and mutants thereof.
NRRL B-30059, NRRL B-30060, NRRL B-30061, NRRL B-30062, and NRRL B-30063 were deposited on Nov. 5, 1998 at the Agricultural Research Culture Collection (NRRL), International Depository Authority; 1815 North University Street; Peoria, Ill., 61064 U.S.A. All strains were deposited under the terms of the Budapest Treaty.
4. Amino Acid Production and Purification
Other embodiments of the invention are drawn to processes for the production of an amino acid in a raffinate-containing medium. Such processes involve (a) the culturing of an improved raffinate resistant bacterial strain and (b) recovery of the amino acid from culture media.
In a first specific embodiment, the invention provides a process for the production of an amino acid comprising:
(a) culturing a bacterial B strain in a medium containing raffinate, whereby said strain is obtained by the following method:
(i) selecting a parental bacterial strain A that produces an amino acid; (ii) subjecting said parental strain A to mutagenesis; (iii) selecting an improved raffinate-resistant bacterial strain B; and
(b) recovering the amino acid from the culture media.
Selection of parental bacterial strains, mutagenesis and the selection of microorganisms of the invention with improved raffinate resistance may be done as heretofore described.
In preferred embodiments of the invention, other processes are drawn to parental strains selected from the group consisting of L-lysine producing Corynebacterium and Brevibacterium microorganisms, and a most preferred embodiment of the invention is drawn to a parental strain that is Brevibacterium that produces the amino acid L-lysine.
The processes of the invention may further vary by way of the specific method of culturing the microorganisms of the invention. Thus, a variety of fermentation techniques are known in the art which may be employed in processes of the invention drawn to the production of amino acids.
Illustrative examples of suitable carbon sources include, but are not limited to: carbohydrates, such as glucose, fructose, sucrose, starch hydrolysate, cellulose hydrolysate and molasses; organic acids, such as acetic acid, propionic acid, formic acid, malic acid, citric acid, and fumaric acid; and alcohols, such as glycerol.
Illustrative examples of suitable nitrogen sources include, but are not limited to: ammonia, including ammonia gas and aqueous ammonia; ammonium salts of inorganic or organic acids, such as ammonium chloride, ammonium phosphate, ammonium sulfate and ammonium acetate; and other nitrogen-containing, including meat extract, peptone, corn steep liquor, casein hydrolysate, soybean cake hydrolysate and yeast extract.
Generally, amino acids may be commercially produced from the invention in fermentation processes such as the batch type or of the fed-batch type. In batch type fermentations, all nutrients are added at the beginning of the fermentation.
In fed-batch or extended fed-batch type fermentations one or a number of nutrients are continuously supplied to the culture, right from the beginning of the fermentation or after the culture has reached a certain age, or when the nutrient(s) which are fed were exhausted from the culture fluid. A variant of the extended batch of fed-batch type fermentation is the repeated fed-batch or fill-and-draw fermentation, where part of the contents of the fermenter is removed at some time, for instance when the fermenter is full, while feeding of a nutrient is continued. In this way a fermentation can be extended for a longer time.
Another type of fermentation, the continuous fermentation or chemostat culture, uses continuous feeding of a complete medium, while culture fluid is continuously or semi-continuously withdrawn in such a way that the volume of the broth in the fermenter remains approximately constant. A continuous fermentation can in principle be maintained for an infinite time.
In a batch fermentation an organism grows until one of the essential nutrients in the medium becomes exhausted, or until fermentation conditions become unfavorable (e.g., the pH decreases to a value inhibitory for microbial growth). In fed-batch fermentations measures are normally taken to maintain favorable growth conditions, e.g., by using pH control, and exhaustion of one or more essential nutrients is prevented by feeding these nutrient(s) to the culture. The microorganism will continue to grow, at a growth rate dictated by the rate of nutrient feed. Generally a single nutrient, very often the carbon source, will become limiting for growth. The same principle applies for a continuous fermentation, usually one nutrient in the medium feed is limiting, all other nutrients are in excess. The limiting nutrient will be present in the culture fluid at a very low concentration, often unmeasurably low. Different types of nutrient limitation can be employed. Carbon source limitation is most often used. Other examples are limitation by the nitrogen source, limitation by oxygen, limitation by a specific nutrient such as a vitamin or an amino acid (in case the microorganism is auxotrophic for such a compound), limitation by sulphur and limitation by phosphorous.
Methods for the recovery and purification of amino acids, particularly L-lysine, are well known to those skilled in the art. Typically, an amino acid may be recovered from the growth medium by cation exchange, after centrifugation and filtration to remove cells. U.S. Pat. No. 5,684,190 describes the recovery of an amino acid such as L-lysine that involves (1) passage of the amino acid containing aqueous solution over a primary cation exchange resin to absorb the amino acid onto the resin at a pH lower than its isoelectric point, subsequently followed by elution of the amino acid by increasing the pH with ammonium hydroxide to produce a first solution; and (2) passage of the first solution over a secondary cation exchange resin in a similar fashion to further eliminate impurities.
Another example may be provided by U.S. Pat. No. 4,714,767, which provides a process for separating basic amino acids from an aqueous solution using cation exchange resin towers in series. The process comprises repetitive adsorption and elution steps in sequence, wherein the washing water employed in the absorption and elution steps is obtained by recycling the latter portion of a liquid discharged from a first tower absorption step or elution step in a subsequent cycle.
Eluants obtained from such cation exchange isolation procedures may be concentrated by evaporation, which additionally provides for the elimination of ammonia. The amino acid may then be crystallized from solution with hydrochloric acid, producing for example L-lysine.HCl.2H 2 O. After centrifugation or filtration, the isolated L-lysine crystals are dried.
EXAMPLES
Example 1
Mutagenesis, Screening and Selection for Improved Raffinate Resistant Microorganisms
The lysine producing strains such a T125, L58.23, and 96T116, whose growth is inhibited by higher concentrations of raffinate, were subjected to mutagenesis, and mutants showing resistance to higher concentrations of raffinate were recovered. For mutagenesis, bacterial cultures were grown to mid-log phase in medium B (Table 1), pelleted by centrifugation and resuspended in 2 mL of filter-steriled TM buffer in a 15 ml polypropylene conical tube (Tris.HCL 6.0 g/L, maleic acid 5.8 g/L, (NH 4 ) 2 SO 4 1.0 g/L, Ca(NO 3 ) 2 5 mg/L, MgSO 4 .7H 2 O 0.1 g/L, FeSO 4 .7H 2 O 0.25 mg/L, adjusted to pH 6.0 using KOH). The 2 mL cell suspension was mixed with 50 μL of a 5.0 mg/L solution of N′-nitro-N-nitrosoguanidine (NTG), then incubated at 30° C. for 30 minutes. An untreated cell suspension was similarly incubated as a control for estimating the kill rate. After incubation, 10 mL of TM buffer was added to each tube, and the cells were pelleted by centrifugation, washed twice in TM buffer, and resuspended in 4.0 mL of 0.1 M NaH 2 PO 4 (phosphate buffer) adjusted to pH 7.2 using KOH. The washed cell suspensions were further diluted in phosphate buffer, and aliquots were spread on plates of medium A (Table 1). After incubation at 30° C. for 4–6 days, colonies growing on medium A agar were picked and tested for improved potential to produce L-lysine from dextrose in shaker flasks and fermentors.
Example 2
The Growth of Strains in Raffinate Media
For each tested strain (Table 2), 0.1 mL of frozen culture was inoculated into a 250 mL baffled flask containing 20 mL raffinate medium C (Table 1), then incubated for 18 hours at 30° C., at 240 rpm. After incubation, 50 μl of culture was removed and diluted to a ratio of 1:100 in 0.1 N HC 1 solution. The optical density (OD) of the diluted sample was measured at 660 nm with a spectrophotometer. The results are shown in Table 2. All strains with improved raffinate resistance (RF), L63.148, L64.132, L69.53, and L69.74, grew better (higher OD) than their parental strains, 108T125, LS8.23, and 96T116, in the raffinate medium C.
Example 3
Dextrose Consumption, Growth, and Lysine Production in Shaker Flask Fermentation
For each strain, 0.1 mL of a frozen culture was inoculated into a 250 mL baffled flask containing 20 mL of seed medium C and incubated for 18 hours at 30° C., 240 rpm. Two mL of seed culture were used to inoculated 20 mL of fermentation medium D in a 250 mL baffled flask. The flasks were then shaken for 24 hours at 30° C. and 240 rpm. After 24 hours of fermentation, samples were removed for analysis. To measure dextrose concentrations, 100 μL of sample were removed and diluted 1:50 with deionized (DI) water and measured, with a YSI biochemistry analyzer (Yellow Springs Instrument Co. Inc.). L-lysine concentrations were determined by HPLC. Optical density measurements were taken to measure growth as described in Example 2. Results are presented in Table 3; all raffinate resistant strains, L63.148, L64.132, L69.53 and L69.74, grew better, used dextrose more efficiently, and produced more L-lysine than their parent strains, 108T125, L58.23, and 96T116.
Example 4
Growth and L-Lysine Production in Bench Scale Fermentors
Bench scale fermentations were set up using a two stage inoculum protocol. The first stage media was composed of 50.0 g/l sucrose, 3.0 g/l K 2 HPO 4 , 3.0 g/l urea, 0.5 g/l MgSO 4 —7H 2 O, 30.0 g/l soy peptone, 5.0 g/l yeast extract, 0.765 mg/l biotin, 3.0 mg/l thiamine HCl, and 0.125 g/l niacinamide. A 2 liter baffled shake flask containing 500 mls of this media was inoculated with the culture and incubated at 30° C. and 250 rpm for 19 hrs. At this point, 22.5 mls of the mature first culture was used to inoculate the second stage inoculum media.
The second stage inoculum was prepared with 3000 mls of medium in a 6.6 liter fermentor. The medium formulation was 20.0 g/l (db) corn steep liquor, 10.0 g/l ammonium sulfate as raffinate, 12.0 mg/l MnSO 4 —H 2 O, 3.0 mg/l biotin, 3.0 g/l thiamine HCl, 125 mg/l niacinamide, 0.5 mls/I antifoam, and 60 g/l dextrose, sterilized separately as a 360 g/l solution and added to the fermentor just prior to inoculation. The fermentor was operated at 32° C., 1.2 vvm air, 600 rpm, and a pH control point of 7.2. pH control was accomplished by the addition of NH 3 or NH 4 OH. After 18–20 hrs the inoculum was considered mature and used to inoculate the production stage vessel.
Production stage medium was composed of 40 g/l (db) corn steep liquor, 20 g/l ammonium sulfate as raffinate, 12.0 mg/l MnSO 4 —H 2 O, 0.75 mls/i antifoam and 12 g/l dextrose, sterilized separately as a 250 g/l solution and added just prior to inoculation. Media formulation was based on a 2.1 liter initial volume which includes 500 mls of mature second stage broth as inoculum. Operating parameters were the following: 32° C., 2.1 vvm air, and an initial and control point pH of 7.2. pH control was again done with NH 3 or NH 4 OH. Agitation was initially 600 rpm, increased to 700 rpm at 9 hrs culture time and 900 rpm at 19 hrs culture time. The fermentation was fed on demand, as indicated by pH increases due to dextrose depletion, a mixture of dextrose and ammonium sulfate. The feed was prepared by sterilizing separately 2310 g dextrose+800 mls water and a volume of raffinate containing a total of 176 g of ammonium sulfate, then combining the two solutions upon cooling to ambient temperature. Total fermentation time was 48 hrs. The vessel size was the same as that used for the second stage inoculum development.
Results of an experiment comparing the parent strain to the above described isolates in bench scale fermentation are presented in Table 4.
Example 5
Production of Raff nate
As previously described, raffinate may be qualitatively characterized according to the specific amino acid produced in the fermentation medium from which the raffinate is isolated. The example provided herein is for the production of lysine-raffinate. However, one skilled in the art would know, other types of raffinate, e.g., valine- or isoleucine-raffinate, etc., may be similarly produced by simply starting with the appropriate fermentation broth, e.g., valine or isoleucine fermentation broth, etc.
As a first step in the production of lysine-raffinate, lysine fermentation broth is diluted to a lysine concentration of 65.5 g/l. After ultrafiltration to generate a permeate with a lysine concentration of 40.3 g/l, the permeate is then concentrated to 123 g/l lysine with a total dry solids concentration of 207 g/l.
The permeate concentrate is then fed into a chromatographic separation system, for example I-SEP or C-SEP produced by Advanced Separation Technologies Incorporated (St. Petersburg, Fla.). Ion exchange chromatographic separation systems are commonly known in the art, as exemplified by U.S. Pat. Nos. 4,808,317 and 4,764,276, which are incorporated herein by reference. The waste effluent obtained therefrom is considered the “dilute lysine-raffinate” solution. The dilute lysine-raffinate solution has a pH of 5.1 and it contains 34.3 g/l ammonium sulfate and 2.8 g/l lysine with a total solids level 67 g/l.
The dilute lysine-raffinate solution is concentrated to 295 g/l total solids. Quantitated components of this “concentrated lysine-raffinate” solution include the following: 137.9 g/l ammonium sulfate, 14.8 g/l lysine, 8.7 g/l valine, 8.1 g/l alanine, 2.4 g/l lactic acid and 2.2 g/l acetic acid. This concentrated lysine-raffinate solution is used in media preparation.
TABLES
The following tables are referenced in the Examples section.
TABLE 1
Media Employed in Examples 1, 2, and 3
Ingredients (amount/L)
A
B
C
D
Glucose
20
g
30
g
68
g
Sucrose
50
g
L-Alanine
0.5
g
0.5
g
L-Methionine
0.5
g
0.5
g
L-Threonine
0.25
g
0.25
g
Biotin
0.05
mg
0.756
mg
0.003
g
0.405
mg
Thiamine
0.2
mg
0.003
g
0.003
g
Niacinamide
0.05
g
0.125
g
0.125
g
Polypeptone Peptone
20
g
(BBL)
Beef Extract (BBL)
5
g
Corn Steep Liquor 1
20
g
Raffinate 2
60
g
10
g
40
g
Urea
2.5
g
3
g
50
g
Amonia Sulfate
10
g
K 2 HPO 4
3
g
KH 2 PO 4
1
g
MgSO 4 .7H 2 O
0.4
g
0.5
g
MnSO 4 .H 2 O
0.01
g
0.01
g
0.01
g
NaCl
1
g
FeSO 4 .7H 2 O
0.01
g
CaCO 3
50
g
50
g
Agar
15
g
pH (before autoclave)
7.2
7.3
7.4
7.4
1 The amount of corn steep liquor is expressed as grams of dried solids per liter of medium.
2 The amount of raffinate is expressed as grams of ammonia sulfate per liter of medium.
TABLE 2
The Growth of Strains in Medium C Containing Raffinate
Strain
108T125
L63.148
L58.23
L64.132
96T116
L69.53
L69.74
Type
Wild 1
RF 2
Wild
RF
Wild
RF
RF
OD 660
15.9
27.4
27.1
34.5
22.2
31.6
30.3
1 Strains 108T125, L58.23, and 96T116 are parent and wild type strains used to generate the improved raffinate resistant strains of the invention.
2 Strains L63.148, L64.132, L69.53, and L69.74 are improved raffinate resistant (RF) strains derived from their wild type parental strains as described.
TABLE 3
The Dextrose Consumption (Dex), Growth (OD 660 ), and Lysine
Production (Lys) of Strains in 24 hr Shaker Flask Fermentation in
Medium D
Strain
108T125
L63.148
L58.23
L64.132
96T116
L69.53
L69.74
Type
Wild
RF
Wild
RF
Wild
RF
RF
Dex, g/L
25.9
66.7
40.6
68.8
45.8
78.8
76.6
OD 660
20.5
43.2
26.3
47.9
30.5
47.4
42.8
Lys, g/L
9.4
18.8
14.1
23.3
15.5
24.6
23.2
TABLE 4
Parent and Progeny Comparison of Growth (OD660)
and L-lysine Production in 6.6 1 fermentors
Strain
OD @ 660 nm
Total Product 1
g lysine/1/hr 2
96T116
Wild
83.8
583 g
5.78
L69.53
RF
112.5
776 g
7.70
L69.74
RF
122.4
807 g
8.01
L69.100
RF
93.3
745 g
7.48
1 Total Product denotes total grams of lysine in the fermentor at harvest.
2 Calculation based on the initial 2.1 liter volume. | The present invention relates to the fields of microbiology and microbial genetics. More specifically, the invention relates to novel bacterial strains and processes employing these strains for the fermentative production of amino acids such as threonine. |
CROSS-REFERENCE TO RELATED APPLICATIONS
None.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
This invention relates to gimbal systems, and more particularly, to a stabilized common gimbal (SCG) for use on commercial vehicles and on military vehicles employed in battlefield environments. The SCG of the present invention is usable with a variety of sensor suites such as are used on different military vehicles and is particularly advantageous over a conventional manual adjustment gimbal systems in that the remote operation of the SGC does not unduly expose a vehicle crew to danger in combat situations by requiring a crew member to exit the vehicle to perform manual adjustments.
Heretofore, gimbal systems have been built for use either with a particular set of sensors, or for use on a specific vehicle. Accordingly, it is currently impossible to use a gimbal system interchangeably on a variety of vehicles, or to swap out one sensor or set of sensors with another. This has obvious ramifications when it comes to the amount of inventory necessary to cover possible operational contingencies, the amount of training required for service personnel having to install and maintain a variety of different systems, as well as for vehicle personnel who need to know and understand the nuances of each gimbal system they may be required to use.
With regard to gimbal systems employed on combat vehicles, such vehicles, by their nature, are expected to operate over a wide variety of terrain and move through numerous positions as they traverse a battlefield. Modem military vehicles are equipped with a variety of sensors enabling them to locate and identify other forces moving over the same terrain. To properly function, it is desirable that the platform on which these sensors are mounted remain inertially stable regardless of the vehicle's gyrations. Heretofore, maintaining a stable platform has required manual operations performed by the crew. Since the crew is subject to the same lurching as the vehicle and is exposed to enemy fire, their ability to manually maintain a stable platform has not always been optimum. In addition, the crew's activities in trying to stabilize the sensor platform has exposed the crew to substantial risk. Accordingly, there is a need for a common gimbal system which automatically provides a stable platform for a variety of sensors, and which reduces the risk to the crew from exposure to enemy fire.
BRIEF SUMMARY OF THE INVENTION
Briefly stated, the present invention provides a stabilized common gimbal. The term “common” is used because the same stabilized gimbal system can be installed on a wide variety of commercial vehicles and military vehicles, the latter of which are employed in combat situations. It is a feature of the present invention that the SCG is interchangeably usable with a wide variety of sensors or sensor packages or sensor suites and that the SCG regardless of the sensors installed on it can automatically stabilize a sensor package to a particular line-of-sight (LOS).
The SCG of the present invention is a two axis (azimuth and elevation) gimbal capable of stabilizing a payload of primary sensors weighing nominally one hundred pounds (45.5 kg) to an average positional accuracy of 25 μrad. The SCG further is capable of mounting a secondary sensor payload of nominally fifty pounds (22.7 kg) that is independent of the moving axes of the gimbal. The primary and secondary sensor payloads are environmentally protected. The SCG employs three gyroscopes which are respectively used to detect inertial rates in the azimuth axis, the elevation axis, and the roll axis. The inertial rate information provided by the gyroscopes is utilized by a gimbal control during slewing of a sensor payload and its stabilization. Even though there is no controlled roll axis in the two axis system provided, the roll gyroscope is used for decoupling the azimuth and elevational axes. Further, the roll gyroscope assists in an automatic calibration procedure that reduces mechanical design tolerances, making a Gyroscope Assembly Unit (GAU) of the SCG more economical to produce.
The SCG provides an interface for a primary suite of sensors comprising one or more sensors having a common line-of-sight (LOS) and which are stabilized in both azimuth and elevation. An inertial navigation system (INS) provides navigation and measures the LOS for the primary suite of sensors relative to inertial space. An Axis Control Unit (ACU) is provided which incorporates hardware and software that provides motor drives, an interface for gimbal motion sensors, an interface to system communications, and control loop closure. The SCG provides electronics, actuators, resolvers, and inertial sensors for stabilizing the LOS of the primary suite of sensors against vehicle motion or other disturbances (e.g. wind loads). Remote positioning of the LOS of sensors in the primary suite is also accomplished. The remote commands can originate from an operator's Common Control Panel (CCP) joystick or from commands over the system's serial interface. System serial interface commands may originate from a tracker in the local system or from commands over any appropriate communication link, such as a radio. The SCG further provides an interface for a secondary suite of sensors again comprising one or more sensors. This second suite of sensors is not stabilized and has a base platform independent from the primary suite of sensors. Finally, the SCG includes an inherent capability for boresighting the sensors comprising the primary suite of sensors, and for retaining the boresight thereafter. The SCG has a signature which is minimized in the visible, radio-frequency (RF), and infrared (IR) portions of the spectrum.
The foregoing and other objects, features, and advantages of the invention as well as presently preferred embodiments thereof will become more apparent from the reading of the following description in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In the accompanying drawings which form part of the specification:
In the drawings,
FIG. 1 A is a perspective view of the stabilized common gimbal of the present invention with ancillary equipment such as a radar and FLIR mounted to the gimbal, and
FIG. 1 B is a similar view with the radar removed;
FIG. 2 A is a simplified exploded perspective view of the housing components of the stabilized common gimbal of the present invention;
FIG. 2 B is a detailed exploded perspective view of the components of the stabilized common gimbal of the present invention;
FIG. 3 A is a perspective view of the gyroscope assembly component of the stabilized common gimbal;
FIG. 3 B is a perspective view of the housing of the stabilized common gimbal, illustrating the placement of they gyroscope assembly component;
FIG. 4 is a circuit block diagram for the gyroscope assembly component;
FIG. 5 is a simplified block diagram representation of axes control unit used with the stabilized common gimbal;
FIG. 6 is a circuit block diagram for the axes control unit; and,
FIG. 7 is a state diagram of the operating states for the control system for the stabilized common gimbal of the present invention.
Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
Referring to FIGS. 1 A and 1 B , a stabilized common gimbal (SCG) of the present invention is indicated generally at 10. As is described herein, the SCG 10 is a two-axis (elevation and azimuth) gimbal consisting of an azimuth housing 12 , rotationally secured to a mounting flange 14 for attachment to a vehicle, a mast, or other support structure (all not shown) and an elevation housing 16 fitted to azimuth housing 12 . Azimuth housing 12 provides for rotational movement within a predetermined range about an azimuth axis, while elevation housing 16 provides for independent rotational movement within a predetermined range about an elevation axis.
As seen in FIGS. 2 A and 2 B , azimuth housing 12 incorporates an axially mounted azimuth drive ring motor 17 , an axially mounted azimuth rotational shaft driven by the ring motor, and a number of associated bearings 20 , o-ring type seals 22 , washers 24 , and wave springs 26 , as best seen in FIG. 2 B , to stabilize azimuth housing 12 against vehicle motion. During operation, azimuth drive ring motor 17 rotates azimuth housing 12 about a vertical axis relative to mounting flange 14 , thereby providing the first axis of rotation (azimuth) for SGC 10 . Rotation of the azimuth housing about the first axis of rotation (azimuth) of the SGC causes the elevation housing to rotate together therewith, and this rotation is measured by a brushless azimuth resolver 25 secured to the azimuth housing by a suitable mounting bracket 25 a . An azimuth hard stop assembly within housing 12 prevents the azimuth housing from rotating outside of a predetermined range (which is preferably ±250° about a nominal zero position) by providing a block or striker which engages a pair of striker pawls secured to the azimuth rotational shaft driven by ring motor 17 .
Elevation housing 16 consists of an upper housing 28 and a lower housing 30 . The elevation housing contains the components of an elevation shaft or gimbal 32 . The gimbal extends from the left and right sides of the elevation housing 16 to provide a mounting structure for a primary sensor payload 33 such as shown in FIGS. 1 A and 1 B . The weight of this payload can be up to 100 pounds (45.5 kg) depending on the weight distribution. Payloads greater than 100 pounds can be accommodated by the gimbal, but with a degradation in stabilization performance. Further, the primary sensor payload may be divided into a left sensor pod 36 and a right sensor pod 34 , each containing a primary suite of sensors as more fully described hereinafter. To drive gimbal 32 within a predetermined arcuate range (preferably ±45°), a pair of axially mounted elevation drive ring motors 38 A and 38 B are fitted within elevation shaft 32 , together with associated electronics and housings for the stabilizing gyroscopes, as is more fully explained below. On each end of elevation shaft or gimbal 32 , extending beyond elevation housing 16 , is a mounting flange 40 . These flanges are suitably sealed by a combination of bearings 42 , wave springs 44 , and o-ring type seals 46 . Those of ordinary skill in the art will recognize that the specific configuration of each mounting flange 40 may be adapted to conform to the mounting requirements of the primary sensor payload pods 34 , 36 mounted thereto. Accordingly, the left and right ends of gimbal 32 need not be identically configured. During operation, drive ring motors 38 A , 38 B rotate elevation shaft 32 about a horizontal axis relative to azimuth housing 12 , thereby providing the second axis of rotation (elevation) for SGC 10 . The amount of this rotation is measured by a brushless elevation resolver 31 mounted to lower elevation housing 30 . In addition to supporting the primary suite of sensors on elevation shaft or gimbal 32 , SCG 10 is also capable of supporting an optional secondary payload 39 which is mounted to upper housing 28 of elevation housing 16 . This secondary payload 39 , which can weigh up to 50 pounds (22.7 kg), comprises a secondary suite of sensors which operate independently of the moving axes of SGC 10 . Any motion and/or control of this secondary sensor payload is provided by systems embedded in the secondary suite of sensors, and this allows the sensors of the secondary suite to function independently of the primary line of sight (LOS) utilized by the primary sensor payload. In FIG. 1 A , an MSTAR tripod mount M is secured to upper housing 28 to provide the mounting surface for the secondary payload which includes, for example, a MSTAR Doppler Radar unit R. It is a feature of the invention that the SCG is capable of taking long range sensor data; for example, returns from radar unit R, and slewing the primary suite of sensors to a LOS dictated by the long range sensor data. This is done to assist in shorter visual range identification of an object of interest.
The SGC preferably provides nominal performance tracking of 100 μrad/second and meets a nominal stabilization requirement of 25 μrad. To achieve these performance and stabilization requirements, accurate rate of movement feedback is provided by three separate gyroscopes, 100 and 102 , for independent azimuth and elevation control, and a third, roll, gyroscope 104 which is used to facilitate an auto calibration procedure. A gyro assembly unit (GAU) 106 houses the gyroscopes 100 , 102 , and 104 , which are mounted in quadrature within the unit. Also housed within the GAU is the associated electronics required to convert rate inputs from the gyroscopes and serially communicate this information to an external Axes Control Unit (ACU) 108 which contains the hardware and software that controls SCG 10 .
In FIGS. 3 A and 3 B , GAU 106 is shown to comprise a rectangular framework 110 , within which a GAU circuit board 112 and the gyroscopes 100 , 102 , and 104 are secured. A circuit card assembly CCA is connected to each gyroscope to provide input power conditioning for the power supplied to the gyroscope and signal conditioning to output signals provided by the gyroscope. Secured to one face of framework 110 is a face plate 114 having an input/output connector 116 for effecting required electrical connections to circuit board 112 and the gyroscopes. A cover 118 encloses the remaining sides of the framework and is secured to face plate 114 by suitable connectors such as bolts or screws to form a self-contained unit. As seen in FIG. 3 B , the GAU is suitably mounted inside gimbal 32 with an electrical connector (not shown) connected to connector 116 . The external dimensions of GAU 106 are limited by the interior diameter of the elevation shaft or gimbal 32 and preferably do not exceed 4 inches (10.1 cm) per side. It is also preferable that the GAU be environmentally sealed, including sealing against electromagnetic interference. The GAU is removable from elevation shaft or gimbal 32 , through one end of thereof, by removal of the appropriate mounting flange 40 .
As seen in FIG. 3 A , three gyroscopes 100 , 102 , and 104 are mounted within framework 110 in quadrature with each other. The angles between the gyro mounting surfaces are held only to 90°±1°. A gyroscope electronic calibration software routine employed by the SCG reduces the need for expensive, accurately machined quadrature angles. Prior to installation in an SCG, each GAU is first electronically calibrated for its own manufacturing tolerances. The calibration data is stored within a non-volatile EEPROM mounted within the GAU assembly. Each of the gyroscopes 100 , 102 , and 104 is installed using mounting rings 111 supplied by the manufacturer. Mounting ring inspections ports (reference ports) are mounted within 1° of a sense axis (not shown) for each of the gyroscopes. This facilitates proper sensing alignment of each gyroscope during installation. Gyroscopes 100 , 102 , and 104 are mounted so as to have an orientation that senses the azimuth, elevation, and roll axis of SGC 10 . An output from each of the gyroscopes provides a rate output signal indicative of the rate of movement about the associated axis which a respective gyroscope is sensing. Once the rate output signal is electronically scaled and filtered, it is converted and transmitted serially to ACU 108 for use in a feedback control loop designed to maintain a desired position and orientation for the SCG. All gyroscope communication, conversion and EEPROM electronics, are mounted inside GAU 106 on circuit board 112 , and a suitable electrical interface harness provides for connecting circuit board 112 to ACU 108 through input/output connector 116 for communications and power. The main hardware functions of GAU circuit board 112 are shown in FIG. 4 and include power regulation and filtering of filtered MIL-STD-1275. A protected external 12 Vdc power source (not shown) provides power from the ACU, through input/output connector 116 , for the gyroscope signal conditioning as described above, analog to digital conversions, EEPROM data storage, controller functions, and synchronous serial communications with ACU 108 . Synchronous serial communications maintained between GAU 106 and ACU 108 are preferably RS485 compatible and the data transfer rate is up to 150 Kbps.
In the preferred embodiment, external signals supplied to input/output connector 116 of the GAU can withstand ESD environments, including an ESD pulse of up to 3999 volts (when switched from an energy source capacitance of 100 pf through a 1500 ohm resistance). ESD voltage design protection is measured from each signal to its interface circuit's relative electrical ground. Nuclear survivability design requires use of suitably hardened components. Operation of GAU 106 through a nuclear event is not required, and the GAU depends upon any external power source to have a nuclear event detector and appropriate circumventing circuitry to shut off the power to the GAU. Electromagnetic pulse survivability for the GAU is a function of the GAU's physical design and attached system cabling. This cabling is preferably double braid shielded cabling. The external interface signals are designed to withstand direct shorts to potentials from electrical ground to 30 volts for a period of up to 10 seconds. Further, GAU 106 is preferably capable of continuously operating at temperatures of −31.7° C. (−25° F.) to+51.7° C. (+160° F.).
Gyroscope rate output signals from GAU 106 are received at ACU 108 which, as noted, contains hardware and software for controlling SCG 10 , and which supplies power to the SCG. As shown in FIG. 5, ACU 108 provides an external interface between azimuth servo motor 17 , elevation servo motors 38 A , 38 B , GAU 106 , the primary and secondary sensor payloads 33 , 39 , up to two common control panels (CCP's) 200 , and a system central processor (SCP) 202 . The ACU mounts within the vehicle or structure to which SCG 10 is secured. Connections between the ACU and SCG are by shielded cables 204 routed through gimbal mount bulkhead connectors (not shown) to the appropriates systems contained within SCG 10 . The SCG's motor control and drives, motor temperature sensors, GAU and resolvers are either controlled or sensed over the connecting cables 204 by the hardware contained within ACU 108 . An external system processor 209 is provided with a serial link (SL) to a system central processor (SCP) 202 of ACU 108 . In a remote operating mode, the ACU receives gimbal commands over the serial link. In all modes of operation, the ACU exchanges system level status and configuration information over the serial link to illuminate appropriate indicators on CCP 200 . Each CCP 200 includes a strain gauge type of joystick (SGJ), an AT keyboard (ATK), a cursor control (CC) which is serial mouse capable, various discrete switch inputs (SI), and a number of indicators (IN).
Physically, as seen in FIG. 6, the ACU is divided into two chambers 206 , 208 to reduce electromagnetic interference. ACU 108 is configured to withstand the same environmental conditions, as set forth above, for GAU 106 . A power chamber 206 includes the hardware required to receive external power from an external connector 207 and to filter and distribute the power throughout SCG 10 to azimuth motor 17 and both elevation motors 38 A , 38 B , as well as to the primary and secondary sensor payloads 33 , 39 . Included in chamber 206 , for power flow distribution, is a circuit breaker 210 configured to protect the ACU and SCG components against power surges or spikes from the external power source, and an EMI diode assembly and filter 212 which filters the incoming power. From filter 212 , power is supplied to an ACU power supply circuit board 214 , from which it is distributed to each of three servo amplifiers 261 A , 261 B , 216 C , a parking brake relay 218 , and SCP 202 through a connector 219 and associated interconnection and wiring harnesses (not shown). The azimuth and elevation servo motors 17 , 38 A , 38 B , are each brushless three-phase motors, and each motor is powered from an associated servo amplifier 216 A , 216 B , 216 C in the ACU. When the servo motor windings are not powered, parking brake relay 218 provides a dynamic parking brake for SCG 10 by shunting the servo motor windings.
Chamber 208 of the ACU houses all low level analog and digital signal circuitry, and this circuitry is shielded from electromagnetic interference associated with power supply 214 and servo amplifiers 261 A , 261 B , 216 C . Installed in chamber 208 is a fan assembly 222 and associated temperature sensors so to provide cooling air circulation, an ACU Interface (AI) circuit board 224 and SCP 202 . The SCP is preferably a stackable PC 104 processor circuit card assembly, and the SCP communicates with AI circuit board 224 via the 16-bit PC 104 bus. Additional circuit card assemblies may optionally be included on the PC 104 bus in a stackable configuration if needed for future systems. External connections to the SCP are provided through AI circuit board 224 and are for a serial mouse interface, an AT keyboard interface, a VGA interface, and an 10 baseT Ethernet (RJ45) interface. An additional diagnostic RS232 serial link for a remote terminal and test acquisition connector are also available on the circuit board. All system software for SCG 10 resides on SCP 202 .
Additionally included on AI circuit board 224 are interfaces for CCP 200 , GAU 106 , and the gimbal sensors and control. The circuit board is configured to interface with azimuth resolver 25 and elevation resolver 31 . The AI resolver interface circuits include all components required to excite and monitor resolvers 25 , 31 , and to convert resolver output data to digital data available on the PC 104 bus stack. It is preferable that the resolver data to digital conversion have an accuracy of ±2 arc minutes and be capable of tracking a resolver with an input rate of 60 degrees per second.
To facilitate monitoring of the servo motors 17 , 38 A and 38 B , AI circuit board 224 is configured to receive signals from three motor temperature sensors (not shown) associated with the respective servo motors and the AB and BC motor phases for each servo motor. Commutation of the gimbal motors via the servo amps is provided by the ACU software and DIAs(?).
SCP 202 employs a closed loop control system having two basic states of operation. In the first state, an automated alignment is achieved by execution of a 400 Hz loop in which each pass provides an update to the control servos for azimuth motor 17 and both elevation motors 38 A and 38 B . In the second state, the 400 Hz loop is deactivated, and operator input for diagnostics, or the changing of control servo parameters via CCP 200 , is provided. When primary sensor payload 33 is being positioned, the control loop is closed on either the azimuth and elevation resolvers 25 , 31 (for position control) or on gyros 100 , 102 , 104 (for rate control). Position control is used for stowing the primary sensor payload, i.e. for moving the payload to a predetermined stow location. External position commands may be received from an operator via CCP 200 or from the system communication links. Rate control is a normal, stabilized control mode in which the operator uses the joystick, or a remote input command over the serial link, to point the primary sensor payload. When no operator input commands are received, the control loop regulates the primary sensor payload inertial orientation to remain in a fixed position and attitude.
Upon receipt and recognition of a 400 Hz interrupt signal, control of the system is passed to the 400 Hz control loop software, which responds to operator input settings, switch states, and EEPROM contents to perform the following functions:
Watchdog Timer Strobe
Read Analog Inputs
Read Elevation and Azimuth Resolvers and Check for Travel Limits
Sense Switch States
Determine System Mode
Set Up Control Parameters and Perform Servo Functions
Send Out Data to be Logged
Route Instrument Outputs to the Digital to Analog Outputs
In FIG. 7, system modes and permissible transitions between system modes for the 400 Hz control loop software is illustrated. Upon system power-up or a power reset, the 400 Hz control loop software initializes in a RESET state. The functions performed in this state include hardware and software initialization and power-up tests dependent upon the specific ACU architecture. From the RESET state, the 400 Hz control loop software transitions to a STANDBY state where servo states are set to zero. The system now awaits either a servo action or the entry of an operator command. From the STANDBY state, the 400 Hz control loop software may transition into one of several states, an OPERATOR state, a JOYSTICK state, a pre-calibration or PRECAL state, a STOWING state, or a SLAVE state. If the transition is from the STANDBY state to the OPERATOR state, no transitional actions are performed by the 400 Hz control loop. When the transition from the STANDBY state is to either the JOYSTICK or PRECAL states, the control loop identifies rate servo parameters, enables the drive and servos, and releases the brakes on the stabilized common gimbal. Transition is then completed after a 400 ms wait. If the 400 Hz control loop detects that the position or orientation of the primary sensor package is within a range of restricted motion zones during a transition from the STANDBY state to the JOYSTICK state, the control loop automatically transitions to a restricted motion sub-state of the JOYSTICK state, described in further detail below. During a transition from the STANDBY state to the STOWING state, the control loop identifies position servo parameters, again enables the drive and servos, releases the brakes on the stabilized common gimbal, and waits 400 ms before completing the state transition.
The OPERATOR state is an interactive mode which allows the operator of the system to enter data related to the servo operation, initiate diagnostics, or “peek and poke” memory operations. When in the OPERATOR state, the servos are deactivated, and only a “watchdog” timer reset remains enabled.
In the JOYSTICK state, the 400 Hz control loop operates to follow operator input commands and control the primary sensor payload 33 position and orientation via joystick SGJ. In the preferred embodiment, position and orientation changes are limited to movements within a speed range of 60° per second. To make joystick control smoother, joystick input commands have an acceleration limit. This allows a 60° per second maximum rate to be achieved in a smooth manner, for slewing purposes, while providing adequate sensitivity for target tracking at slower rates of change. A preferred acceleration limit on the joystick input signal is established as a function of the force applied to the joystick.
The only permissible state changes form the JOYSTICK state are to and from a rate limit or RATE_LIM state, or to a BRAKING state. Transitions between the JOYSTICK state and the RATE_LIM state immediately occur when movement of primary sensor payload 33 into a restricted motion zone is detected; and, the restricted motion sub-state of the JOYSTICK state described below is not the current state. During transitions to the BRAKING state from the JOYSTICK state, a preferred timeout of 0.4 seconds is established for stopping all motion of the primary sensor 33 payload, and the brake servo parameters are identified.
The RATE_LIM state is automatically entered from the JOYSTICK state when the restricted motion zone is entered by the primary sensor payload 33 position and orientation. In this mode, rate commands are limited to avoid violating physical travel limits of the primary sensor payload as defined by the SCG. Once the primary sensor payload position and orientation is again outside the restricted motion zone, the 400 Hz control loop returns to the JOYSTICK state, or may enter the BRAKING state.
An additional joystick control state is provided by the PRECAL state. In this state, the 400 Hz control loop limits joystick rate commands, providing a limited capability to drive primary sensor 33 payload position and orientation prior to calibration of the system. This prevents extensive manual positioning and the associated exposure of crew or operators to dangerous environments prior to setting travel limits, etc. Joystick movement rates are limited such that they are not likely to result in damage to the system if primary sensor 33 payload is accidentally directed to a position or orientation outside the operational range of movement. The only permissible state change from the PRECAL state is to the BRAKING state.
During periods of non-use, it is often desirable to have primary sensor 33 payload parked in a predetermined storage position. Accordingly, the STOWING state is used to direct the primary sensor payload to a previously designated position and orientation with respect to the vehicle; for example, a zero elevation and zero longitudinal alignment. If a stow position has not been previously defined, the default position and orientation is the zero-zero attitude. From the STOWING state, the system may transition either into the BRAKING state, or immediately to the POS_LIM state. The latter occurs upon detection of motion of the primary sensor payload into a restricted motion zone. Again, the 0.4 second timeout is used to stop all motion of primary sensor 33 payload, and to identify brake servo parameters.
In addition to being controlled by operator input commands when in the JOYSTICK state, primary sensor 33 payload position and orientation may be driven in response to external position commands when the 400 Hz control loop is in the SLAVE state. These external commands are limited to the restricted travel limits, and are not applicable when the travel limits are exceeded or if a restricted motion zone of movement is entered. In the preferred embodiment, the SLAVE state is utilized to slew the primary sensor payload to a specific radar location. From the SLAVE state, the control loop can transition either directly to the POS_LIM state, upon detecting primary sensor 33 payload movement into a restricted motion zone; or directly to the BRAKING state. The timeout features previously described apply to this transition as well.
The POS_LIM state is automatically entered by the control loop from either the STOWING or SLAVE states when a restricted motion zone is entered by the position and orientation of primary sensor 33 payload. While in this state, rate commands generated from position error information are limited so to avoid violating absolute travel limits of the primary sensor payload. From the POS_LIM state, the control loop may go directly to the STOWING or SLAVE states without performing any transitional actions, or may transition to the BRAKING state. During transition to the BRAKING state from the POS_LIM state, the preferred timeout is again observed for the reasons previously discussed.
The BRAKING state is entered when the operator releases an action switch SI, physical travel limits for primary sensor 33 payload are violated, or when an abnormal condition warranting servo shutdown occurs. The BRAKING state consists of two phases; first, stopping the primary sensor payload motion, and second, disabling the servos and drive units. During normal operation, the hardware itself initiates a shutdown sequence within a fixed period of time.
Three sub-states present within the control loop software are not shown in FIG. 7 . The first, TRANSITIONING_UP is a sub-state of the STANDBY state, and is active when all conditions are met to transition to the JOYSTICK, STOWING, or SLAVE states, but a waiting period is entered while servo hardware is performing startup sequences to support active control of gimbal 32 . The second sub-state, TRANSITIONING_DN is a sub-state of the BRAKING state, and is active when all conditions are met to transition to STANDBY, but a delay is required while the servo hardware is performing shutdown sequences to enter the STANDBY state. The third sub-state is a JOY_DEGRADED state which is a sub-state of the JOYSTICK state. This sub-state limits commands to only those which direct primary sensor 33 payload to move away from its travel limits shown into a region of unconstrained motion.
Finally, a data logging function is called for by the 400 Hz control loop software on every pass through the 400 Hz processing task, unless the control loop is in the OPERATOR state. Logged data is sent out every pass, so that the resulting data rate is thus 400 Hz.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. | A two axis (azimuth and elevation) stabilized common gimbal (SGC) for use on a wide variety of commercial vehicles and military vehicles which are employed in combat situations capable of stabilizing a payload of primary sensors and of mounting a secondary sensor payload that is independent of the moving axes. The SCG employs three gyroscopes, inertial angular rate feedback for providing gimbal control of two axes during slewing and stabilization. In addition the third (roll) gyroscope is used for performing automatic calibration and decoupling procedures. In this regard, the SCG provides an interface for the primary suite of sensors comprising one or more sensors having a common line-of-sight (LOS) and which are stabilized by electronics, actuators, and inertial sensors against vehicle motion in both azimuth and elevation. Remote positioning of the LOS of sensors in the primary suite is also accomplished, with the SCG providing an inertial navigation system (INS) which provides navigation and which detects the LOS for the primary suite of sensors relative to the vehicle. The aforementioned stabilized gimbal employs unique features such as automotive gyro calibration and decoupling algorithm that increases the producibility of the system and the stabilized gimbal has the capability of being remotely controlled via its system serial link where commands may originate from devices such as radio links or target trackers. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is concerned with manufacturing a high-capacity servo-valve body with the aid of wire EDM technology.
2. Discussion of the Prior Art
As is well known, servo valves are used to control devices such as seismic vibrators, linear actuators or reversible motors. Typically such valves consist of a valve body having a series of internal radially-arranged, annular flow chambers. The flow chambers are linearly disposed at selected intervals along the length of the valve body. The central flow chamber is fluidly coupled to an inlet port that may be connected to a source of pressurized fluid. The two outermost flow chambers are connected to first and second drain ports that feed into a low-pressure sump. The other two intermediate flow chambers are connected to first and second outlet ports for directing pressurized fluid to the device to be controlled. A bore, of lesser diameter than the diameter of the annular flow chambers, is machined internally along the length of the valve body, orthogonally intersecting the respective annular flow chambers. A valve spool, consisting of three or more spool-shaped lands separated by stem portions, is slidably mounted within the bore. End caps mounted at each end of the bore include drive means for reciprocating the spool valve laterally within the bore. The drive means may be electrically, hydraulically or pneumatically programmed by a pilot valve of any desired type. A linear variable displacement transducer (LVDT) monitors the position of the valve spool within the bore. Depending upon the position of the valve spool, the lands are designed to block off selected flow chambers. A typical servo valve is described in U.S. Pat. No. 4,593,719.
In operation, when the valve spool is centered, the ports are closed and no action occurs. When the valve spool is moved towards one end of the bore, the inlet port is fluidly coupled to the first fluid outlet port while the second outlet port is open to the corresponding drain port so that the controlled device will perform a function in a first direction. With the valve spool at the opposite end of the bore, the inlet port is open to the second outlet port and the first outlet port is opened to the first drain port so that the controlled device performs its function in a second direction.
In one method of construction, the servo valve body is of cast iron or steel. Fluid passageways in the casting must allow for a smooth transition in flow path between the substantially rectangular annular flow chambers and the circular inlet and outlet pipe fittings demanded by conventional plumbing components. The casting is internally complex and it is difficult to machine the septa between the flow chambers to provide fluid ports with the tolerances required by the lands on the valve spool. Furthermore, cast metals are too soft to retain the sharp shoulders on the septa that are needed for accurate fluid-flow control. Accordingly, the bore is usually honed to a desired diameter. A cylindrical sleeve of hard tool steel is provided, having a plurality of radial ports machined in its wall to communicate with the respective fluid flow chambers. The radial ports in the sleeve are dimensioned to match the lands on the valve spool. The sleeve is inserted through the bore, sealed thereto with gaskets or O-rings. The valve spool then reciprocates inside the sleeve. Alternatively, the sleeve may be inserted and sealed in place using heat-shrink technology. The assembly tends to be bulky because the fanout from the flow chambers to the circular plumbing connections takes up considerable space.
For small servo valves of relatively low capacity that are manufactured in quantity, the above method of manufacture is economical. For large valves that need to be custom-made in only one or two copies, creation of the required molds for casting the valve body is extremely complex and expensive. This invention provides a method for economically making a precision servo valve body that is compact, simple of construction and assembly and that does not requires special castings or sleeves.
SUMMARY OF THE INVENTION
In accordance with this invention, an elongated generally rectangular valve block of a selected material is provided. The valve block includes two end portions and opposite side portions. A central cylindrical passageway, adapted to receive a valve spool, is bored lengthwise through the center of the valve block between the two end portions. At selected intervals along one side portion of the valve block, a plurality of pilot holes are drilled through the valve block from one side portion to the opposite side portion. An electrode wire is inserted through a first pilot hole. An oblong cross slot is cut through the valve block orthogonally to the central passageway by electrical discharge machining technology. The process is repeated for the remaining pilot holes. The respective oblong cross slots are designated as fluid inlet, fluid drain and fluid outlet flow chambers.
A first transition plate is secured to a first side of the valve block over the oblong cross slots. The first transition plate is adapted to block those flow chambers designated as fluid outlet flow chambers and to provide fluid communication between the designated fluid inlet and fluid drain flow chambers and a source of pressurized fluid and a fluid sump respectively. A second transition plate is secured to the opposite side of the valve block. The second transition plate is adapted to block those chambers designated as fluid inlet and fluid drain flow chambers and to provide fluid communication between the designated fluid outlet chambers and a device to be actuated.
In a preferred embodiment of this invention, the valve block is made from heat-treated tool steel and the transition plates are made from mild steel.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other benefits of this invention will be better appreciated by reference to the detailed description of the preferred embodiment and the drawings wherein:
FIG. 1 is an exploded view of the essential parts of the servo valve body;
FIG. 2 is an end view of the valve block of FIG. 1;
FIG. 3 is a side view of a preferred form of the valve block of FIG. 1;
FIG. 4 is a cross section along 4--4 of FIG. 2;
FIG. 5 is a cross section along 5--5 of FIG. 4;
FIG. 6 is a cross section along 6--6 of FIG. 4;
FIG. 7a is a view of one face the left hand transition plate as seen from FIG. 1;
FIG. 7b is a view of the opposite face of the left hand transition plate that is hidden from view in FIG. 1;
FIG. 8 is a cross section along lines 8--8 of FIG. 7a;
FIG. 9a is a view of the face of the right hand transition plate that is hidden from view in FIG. 1;
FIG. 9b is a view of the face of the right hand transition plate as seen FIG. 1; and
FIG. 10 is a cross section along lines 10--10 of FIG. 9b.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An exploded view of a servo valve assembly, generally shown as 10, is exhibited in FIG. 1. The servo valve assembly 10 includes a valve block 12 of generally rectangular shape and right and left transition plates 14 and 16. A valve spool 18 having lands 20, 22, 24 separated by stem portions 26 and 27 fits slidingly in passageway 28 that is bored lengthwise through the valve block 12 between end portions 30 and 32. End caps 34 and 36, which are normally bolted to end portions 30 and 32 respectively, provide drive means for reciprocating valve spool 18. A pilot valve of any well known type (not shown) may be mounted atop pilot-valve block 38. Hydraulic lines 40 and 42 deliver hydraulic control fluid from a pilot valve to the valve spool. The valve spool could, of course be electrically or pneumatically controlled. An LVDT 44 is used to monitor the position of valve spool 18. Bolts such as 46, 48, 50 and 52 may be used to fasten the respective parts in place. It is to be understood that the valve spool, end caps, LVDT and pilot valve block are included in the drawings for completeness but form no part of this invention in and of themselves.
FIG. 2 is an end view of valve block 12 showing passageway 28 and end portion 30. Valve block 12 includes opposite side portions 54 and 56.
FIG. 3 is a side view of valve block 12, showing the left-hand side portion 54. Six oblong cross slots are cut through valve block 12 from one side 54, through to the opposite side 56, orthogonally to passageway 28 (shown as dashed lines in FIG. 3). Cross slots 58 and 60, combined, form a bifurcated inlet flow chamber. Cross slots 58 and 60 could be combined into a single aperture but the format shown is preferred for reasons to be explained under FIG. 4. The outlet flow chambers are formed by cross slots 62 and 63, 64 and 65. The bridges 66 and 68 are provided for structural integrity. Cross slots 70 and 72 serve as drain fluid flow chambers. For engineering design reasons, the cross slots are shown with rounded ends although square ends could be used. A series of tapped holes such as 73 are provided for securing the transition plates 14 and 16 (FIG. 1) to valve block 12 as will be disclosed later. It is to be understood that the drain and inlet fluid flow chambers could be interchanged if desired.
FIG. 4 is a cross section of valve block 12 along line 4--4 of FIG. 2. Cross slots 58-64 and 70, 72 are shown along with passageway 28. Bridges 66 and 68, as before stated, are provided for structural integrity. The septum 57 between apertures 58 and 60 is designed to provide support for the center land 22 of valve spool 18 of FIG. 1 when the valve spool is inserted into passageway 28. Absent the need for such support, the two cross slots 58 and 60 could be combined into a single cross slot of a size comparable to slots 70 or 72.
FIG. 5 is a cross section along line 5--5 of FIG. 4 showing the arrangement of the bridge 66 with cross slot 62 being cut through valve block 12 from a first side 54 to the opposite side 56 orthogonally to passageway 28.
FIG. 6 is a section along line 6--6 of FIG. 4, showing the configuration of cross slot 70.
Preferably, the valve block blank is made from a selected material such as tool steel. Initially in the manufacturing process, passageway 28 is bored out by any desired means. Thereafter, the respective bolt holes as shown in the Figures are drilled and tapped as required. Next, a series of pilot holes are drilled through the valve block blank from one side through to the other side. The pilot holes are positioned laterally along the blank at a convenient place within the outlines of the cross slots at each of the desired cross-slot locations. The valve block blank in then heat treated and hardened. If slight shrinkage or distortion occurs following the hardening process, passageway 28 may subsequently be honed to precise dimensions as needed.
It is preferred to cut the respective cross slots precisely to size using wire electronic discharge machining (EDM) technology. This process is done following the heat treatment to avoid possibility of distortion of the slots which would occur if the EDM operation had been done previous to the heat treatment. Using EDM, a wire electrode is inserted in turn, through each one of the previously-drilled pilot holes. The electrode is programmed to precisely cut through the valve block blank around the desired outline of each cross slot. The residual metal slug that is cut away then drops out from the workpiece. In effect, wire EDM is an electronic band saw where the saw blade is a thin, consumable, moving-wire electrode that never actually touches the workpiece. The metal removal mechanism is one of vaporizing small volumes of the workpiece instead of the cutting or grinding processes used in conventional machine shop practice. Using wire EDM, very precise cuts of great complexity may be made that have a smooth final finish which needs no further honing or grinding. Wire EDM processing is capable of cutting speeds of 15 to 20 square inches per hour even with very hard materials such as tungsten carbide.
An article from EDM Today, entitled Basic Theory, Electrical Discharge Machining, May, Jun., 1991, by E. P. Guitrau, discusses the general principles of EDM technology. U.S. Pat. No. 4,017,706 teaches a method for machining the air gaps of a torque motor assembly using precisely-dimensioned, solid-electrode technology.
The oblong cross slots that are cut through the valve block will form fluid flow chambers when left and right hand transition plates 16 and 14, FIG. 1 are bolted to the side portions 54 and 56 of valve block 12. The transition plates provide smooth flow from the oblong cross slots to the circular connections usually associated with hydraulic plumbing.
FIG. 7a is a detailed view of left hand transition plate 16 as seen in FIG. 1 showing inlet port 80 and fluid drain ports 82 and 84. The ports are circular for connection to standard hydraulic plumbing fittings.
FIG. 7b shows the details of the face of transition plate 16 that is hidden in FIG. 1 and which abuts side portion 54 of valve block 12 when secured thereto. Transition slots 86 and 90 mate with cross slots 70 and 72 respectively, FIG. 3, to provide fluid flow from the cross slots to the two drain ports 82 and 84. Transition slot 88 directs fluid flow from inlet port 80 to both cross slots 58 and 60 which together form the bifurcated inlet fluid flow chamber. Regions 85 and 87 are blanks that seal off the outlet fluid flow chambers 62, 63, 64, and 65. O-ring grooves 92, 94, 96, 98, 100 are provided as shown.
FIG. 8 is a cross section along line 8--8 of FIG. 7b. Shown are the circular inlet and drain ports 80, 82 and 84 as well as the transition slots 86, 88, and 90. O-rings 93, 95, 97, 99 and 101 fit into the corresponding grooves 92, 94, 96, 98 and 100 to provide fluid seals when the transition plates are bolted to side portion 54 of valve block 12 by a plurality of bolts such as 74, FIG. 1, through bolt holes such as 103.
FIG. 9a is a view of transition plate 14 as would be seen from the face that is hidden in FIG. 1, showing outlet ports 102 and 104 which are circular for receiving standard hydraulic fittings.
FIG. 9b is a detailed view of the face of transition plate 14 as seen in FIG. 1 and which abuts side portion 56 as indicated in FIG. 2, of valve block 12. Transition slots 106 and 108 provide fluid flow from cross slots 62, 62 and 64, 65, FIG. 3, to outlet ports 102 and 104. Blanks 110, 112, 114 block flow from cross slots 70, 72, 68 and 60. O-ring grooves 107, 109, 111, 113 and 115 are cut around the transition slots 106 and 108 as well as around blanks 110, 112 and 114 to furnish fluid seals when transition plate is bolted to side portion 56 of valve block 14 by bolts such as 76 which are inserted through bolt holes such as 105.
FIG. 10 is a cross section along line 10--10 of FIG. 9b, showing transition slots 102 and 104, outlet ports 106 and 108 and blanks 110, 112 and 114. O-rings 116, 118, 120, 122 and 124 fit into the corresponding O-ring grooves 107, 109, 111, 113, and 115 respectively as shown in FIG. 9b.
It is preferred that the transition plates 14 and 16 be made of mild steel. The transition slots, the various inlet, outlet and drain ports and the O-ring grooves may be formed by conventional machine shop operations such as milling and boring.
The best mode of manufacture has been disclosed in the previous paragraphs. In assembling the servo valve as a whole, following completion of the valve block, the transition plates are bolted thereto as previously indicated. The valve spool is inserted into passageway 28 and the end caps 34 and 36 and LVDT 44 are bolted in place. Hydraulic control lines 40 and 42 are connected between pilot valve block 38 and end caps 34 and 36.
It will be appreciated that the basic servo valve body that is the subject of this invention is very simple, consisting of but three parts that may be easily assembled and disassembled for maintenance as required. For example, valve block 12 can easily be replaced without disturbing the transition plates and their associated hydraulic plumbing fixtures.
The shapes of the valve body components as illustrated are exemplary only. For example, valve block 12 could be designed with an integral mounting pedestal at its base, rather than being substantially rectangular as shown. The transition plates may each be formed from a single block of cold rolled steel or other material or they could be cast. Other variation will doubtless be conceived of by those skilled in the art but which will fall within the scope and spirit of this invention which is limited only by the appended claims. | A servo valve body is made by first boring a central cylindrical passageway, for receiving a valve spool, through an elongated, substantially rectangular valve block of tool steel. A plurality of cross slots are cut through the valve block, from one side through to the opposite side, at intervals along the length of the block, orthogonally to the axis of the passageway. The cross slots are cut by use of electronic discharge machining technology. The cross slots serve as fluid flow chambers when the cross slots are terminated by transition plates secured to the opposite sides of the valve block. The transition plates provide fluid inlet, outlet and drain ports. The valve block in combination with the transition plates comprises the servo valve body. |
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates generally to electronic musical synthesizers and more particularly keyboard control systems for generating and modififying musical note information.
2. Description of Prior Art
The development of microprocessors has opened up new vistas in a number of diverse fields. In the area of musical instruments, however, the changes brought about by microprocessors are not nearly so profound as one might expect. The microprocessor has found use in connection with piano-type keyboard synthesizers and also in connection with special purpose electronic musical instruments which are unlike traditional musical instruments. The microprocessor's great ability to store, manipulate and control information has not been successfully applied to traditional musical instruments. Horns, woodwinds, and the traditional stringed instruments have a long and rich heritage. These instruments have existed for thousands of years and the methods of playing these instruments have remained essentially unchanged.
Virtuosos have continually pushed the limits imposed by human physiology and the physical inertia of their traditional instruments in an effort to increase the speed and complexity of the music which they produce. Beginners and experts generally play instruments (e.g. guitars) which differ only in quality and not in basic configuration. This allows complete unhindered transference of skills when one gains experience and switches to a better instrument. Microprocessor-based instruments which can be played with the same fingering as the traditional instruments which they emulate offer a great appeal to those who have already had some experience with traditional instruments and do not wish to discard their skills or learn new ones in order to play a microprocessor-based instruments.
What is needed in order to take full advantage of the benefits of microprocessors in connection with traditional-type musical instruments is an input device which is similar in physical configuration to the finger-operated portions of the traditional instruments. Mere physical similarity, however, is not enough to fully realize the benefits. Additionally, the microprocessor-based instrument must be able to respond to traditional fingerings and produce the sounds and notes normally associated with these fingerings on traditional instruments. This still is not enough since it would offer very little advantage to the virtuoso. What is further needed is an input device which will respond normally to traditional fingerings and which is also capable of recognizing a second "short-hand" language of largely non-traditional fingerings which can be utilized by the virtuoso to produce a variety of effects, sequences, sounds, etc. which could not be similarly produced in a traditional instrument without great or impossible difficulty.
When music is examined in a theoretical perspective, it is seen to be essentially mathematical in nature, thus making it especially well suited for microprocessors. A microprocess-based instrument which responds identically to a traditional instrument given the same traditional fingerings yet is capable of greatly enhanced performance when given special "short-hand" commands would benefit both the beginner and expert alike. Such an instrument, especially when coupled with special video display devices for real-time feedback of musical note information, would greatly accelerate learning. Skills acquired in the use of this instrument would be easily transferable to traditional instruments and vice versa.
Prior art devices have provided interesting and valuable improvements in the state-of-the-art, but none has satisfied all of the foregoing needs due to the fact that none of the prior art devices could distinguish between the traditional "long-hand" language of traditional fingerings and a second "short-hand" language. Prior art devices which used a traditionally configured keyboard for long-hand traditional fingering and a separate keyboard for complex functions such as automatic chord generation did not offer nearly the same benefits of a single traditionally configured keyboard which could accept and distinguish between both long-hand and short-hand fingerings.
SUMMARY OF THE INVENTION
This invention provides a multiple language electronic keyboard system for generating and modifying musical note information. An object of the invention is to provide a new musical instrument which can be played using pre-existing traditional instrument playing skills and which requires no additional training for initial use since traditional fingerings will produce traditional results.
Another object of the invention is to provide a second level of operability which allows highly complex music-making without requiring extraordinary dexterity.
The instant invention allows those handicapped by lack of education, talent, motor dexterity, or physical ability to learn and play music more easily than these people could if using traditional instruments.
A still further object of this invention is to facilitate the learning of music playing through audio-visual feedback of the musical note information as well as sounds to the user.
This invention provides a simple "short-hand" means of producing chords and includes means for teaching the traditional "long-hand" means of producing the same chord and further is capable of displaying, visually, the musical makeup of the chord.
A still further object of the instant invention is to provide a multiple-language keyboard which allows multiple and distinct methods of producing chords and which allows the various languages to be used at any time without requiring anything more than fingering the proper pattern of switches.
The keyboard of the instant invention can be viewed as a microterminal adapted for use by an instrument player for communicating musical information to a processor which then can manipulate and implement the information in real time.
A still further object of the instant invention is to provide a synthesized guitar-like instrument capable of greatly enhanced performance in comparison to a traditional guitar.
The invention possesses other objects and features of advantage, some of which of the foregoing will be set forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of this specification. It is to be understood, however, that variations in the showing made by the said drawings and descriptions may be adopted within the scope of the invention as set forth in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a portion of the keyboard system.
FIG. 2 is a block diagram of a portion of the keyboard system.
FIG. 3 is a block diagram of a portion of the keyboard system.
DETAILED DESCRIPTION OF THE INVENTION
The multiple-language electronic musical keyboard system of the instant invention comprises briefly a plurality of manually activated switches 1 arranged in a keyboard matrix of rows and columns with these switches sufficiently proximate to one another to allow a single finger of the user to activate a plurality of switches in a single stroke. Timing means 2 is triggerable by the switches 1. The activation of any switch will trigger timing means 2 which upon being triggered begins timing for a time period t. Timing means 2 can be retriggered by any switch prior to the expiration of t and will then continue timing t seconds beyond the last retriggering. The duration of t is, in the preferred embodiment, user-adjustable. A retriggerable time offers the advantage of minimizing the wait between the last switch activated and the onset of the acoustic event called for by either single or multiple switch activations. Accordingly the "wait" never exceeds t seconds. The keyboard system of the instant invention includes a decoding means 3 which is responsive to the switches 1 and which is controlled by the timing means 2 to read and register, upon the expiration of the time period t, all switches presently activated at the point of the time period expiration. Timing means 2 is an important element of the system and is made necessary by the fact that human users intending to simultaneously activate a number of switches will rarely, if ever, effect a truly simultaneous activation. Timing means 2 provides a time window starting at the activation of the first switch and ending t seconds later during which the user may sequentially activate switches which he intends to activate and believes that he is activating smultaneously. At the end of t seconds the decoding means 3 reads and registers all of the switches presently activated. The decoding means 3 is configured to detect and distinguish between a first language and a language of distinct switch activation patterns.
The first language is characterized by the reading and registration of a switch activation pattern where not more than one switch in any particular column is activated and less than all of the switches in any particular row are activated. The first language is further characterized by the reading and registration of a switch activation pattern where at least one switch in each column is activated and all of the switches in one row are activated. In the preferred embodiment of the instant invention the keyboard is configured in six columns and twenty six rows of switches so that the switch positions are analogous to finger positions on a guitar fretboard. The first language can be seen by those familiar with guitar playing to comprise normal traditional guitar fingering. This includes barre which, in the keyboard aforementioned, would be accomplished by activating all of the switches in one row.
The second language is characterized by the reading and registration of a switch activation pattern where at least two switches are activated in at least one column and the number of switches activated in any row is less than the total number of switches contained in that particular row. This second language of switch patterns does not correspond to normal traditional guitar fingering and accordingly can be used to produce a number of "special effects" such as pre-set chords.
The decoding means 3 can be implemented in a number of different ways including the use of logic gates, diodes, or a software routine. The words "reading and registering" when used in the context of the aforementioned decoder simply mean the acquiring of information relating to the identity of activated switches and storing this information long enough so that it can be passed on to the processing means 4. In the processing means 4 the switch pattern data is translated into musical note information which is then used for a variety of purposes including the generation of appropriate electronic tones corresponding to the notes and also for the generation of alphanumeric representations of these notes. In the preferred embodiment processing means 4 is a digital microprocessor which can be programmed by the user. When the decoding means 3 reads and registers a first language switch pattern the processing means 4 converts these first language patterns into musical note information which corresponds to the notes which would be produced on a traditional guitar were the same fingering used. In the case of the reading and registration of a second language switch pattern, the processor can do an almost unlimited number of things, the most common and useful of which would probably be the generation of pre-stored musical note information corresponding to chords. This would allow an experienced user to instantly generate complex chords merely by using one finger to activate two switches in a single column. The usefulness of the two language system should become immediately apparent. Second language switch activation patterns can also be used to generate pre-stored melodies and anything else which is capable of residing in digital memory.
Electronic tone generation means 5 is connected to the processing means 4 and is responsive to the processor's output of musical note information. The tone generation means 5 is, in the preferred embodiment, a digitally controlled electronic synthesizer which receives its input from the processor. A video character generator 6 is also connected to the processing means 4 and is responsive to its output. The character generator 6 is, in the preferred embodiment, used to generate alphanumeric and/or graphic representations in musical tabulature form of the musical note information which is present at the output of the processor. A display means 7 is connected to the character generator for visually displaying the aforementioned graphics and characters. The display can be a CRT type or any number of suitable electroluminescent or reflective display panels capable of sufficient resolution. Additionally, the character generator 6 can be configured to generate patterns and colors corresponding to musical note information to produce a kaleidoscopic and other visually interesting "special effects".
Learning is especially enhanced by a feature of the instant invention which includes a plurality of electro-luminescent display devices 8 which appear in the drawing as circles in the center of the switches. These electro-luminescent display devices are typically light emitting diodes (L.E.D.s) which are controlled by the processor output through interface 22 which contains the necessary decoding and driver circuitry. Each L.E.D. is associated with each of the switches on a one-to-one basis and is located in close proximity to its associated switch. With proper programming these electro-luminescent devices can be used for prompting the user. A typical application of this feature would be to teach chord fingering. Even a beginning user could learn the simple second language short-hand pattern for generating a pre-set chord. The musical note information generated by the processing means 4 would correspond to that chord and could then be used, with the proper interface, to illuminate the L.E.D.s on the particular switches which the user would have to press to generate the same chord using the first language or long-hand switch pattern. At the same time the display 7 could be used to graphically illustrate the musical makeup of the chord in tabulature form.
In the preferred guitar-like embodiment of the instant invention the envelope signal generation source 9 has an input 10 for signals from a natural vibration source. In the case of the guitar the vibrations would be the vibrations of strings 11. An electric pickup 12 would detect the vibrations of the strings 11 and convert them into voltage signals. In alternative embodiments the natural vibration source could be a human voice, a precussion instrument, or anything else which falls into the general category of having naturally vibrating elements. In this context the word "naturally" is used to distinguish electronically synthesized envelope signals from those which derive from actual physical movement.
An analogue switch means 13 is provided and is typically a voltage controlled amplifier. The analogue switch has, as a signal input, the tone signals generated by tone generation means 5 and has, as its modulating input, envelope signals from the envelope signal generation source 9. The output of the analogue switch means would then be electronic tones from 5 modulated in amplitude by the envelope signals from 9. As an additional feature the envelope signals from 9 can be sampled by the processor 4 through interface 21 (typically a suitable analogue to digital converter) and used to modulate the video display via the character generator 6. A typical application would be to modulate the intensity and/or the color the graphic display in accordance with the intensity of the string vibration. More particularly individual notes within a displayed chord could be intensified as the appropriate strings are activated by the user. The beginner would associate musical tabulature with certain physical actions such as fingering and strumming and should therefore quickly learn to read music.
In alternative embodiments the envelope signal generation source 9 can employ electronically synthesized signals which can be triggered externally either by strumming a string or by any other means capable of producing an electrical signal for triggering the synthetic envelope signal. Additionally, the envelope signal generation source can employ an automatic series of electronically synthesized signals similar to those produced by commonly available automatic rythym synthesizers. In FIG. 1 a mixer amplifier 14 and a speaker 15 are used to aurally reproducing the modulating tones which appear at the output of the analogue switch means 13. Although the preferred embodiment of the instant invention is the aforementioned guitar-like instrument, the invention is capable of embodiment in many other types of instruments. While stringed instruments are especially well suited, the instant invention could be used in a piano-like instrument.
The keyboard system of the instant invention and more particularly the two distinct but compatible languages of switch activation patterns offer substantial benefits to beginners and experts alike. In the hands of a skillful musician a guitar-like instrument embodying the instant invention could be used to produce, in real time, music which was previously available only on carefully produced, dubbed, and mixed studio recordings. By fully exploiting the second language capabilities of the instrument a user could play, in real-time, passages which simply could not be similarly produced on a conventional guitar. | A multiple language electronic keyboard system is disclosed for generating and modifying musical note information. The system includes a plurality of manually activated switches arranged in a matrix of rows and columns with the switches sufficiently close to allow a single finger of the user to activate a plurality of switches in a single stroke. A decoder detects and distinguishes between a first language and a second language of distinct switch activation patterns. Musical note information is generated by a processor which receives information from the decoder concerning the location of each activated switch and the language detected by the decoder. The versatility of this system is further enhanced by the addition of envelope and tone generators and also by visual display devices. In the preferred embodiment the keyboard is arranged to positionally and operationally emulate a guitar fret board. |
FIELD OF THE INVENTION
[0001] The invention relates to the field of wheel processing technique, and particularly relates to a rolling forming method of wheel disc.
BACKGROUND OF THE INVENTION
[0002] In prior art, the CNC (Computerized Numerical Control) spinning forming method is widely used to form the truck wheel discs at home and abroad, The method spins an equal-thickness blank into an equal-strength section with gradually reduced thickness. The technological process of spinning forming method is as shown in FIG. 1 :
[0003] a. Baiting a circular blank and punching a positioning hole for spinning.
[0004] b. Spinning the blank into a wheel disc by the CNC spinning forming method on a tapered circular cylinder exploratory so as to meet the requirements of forming an equal-strength section which gradually becomes thinner.
[0005] c. Processing the excircle and the end surface of the spinning formed wheel disc in a dedicated vertical lathe in order to meet the requirement on the tolerance of the outer diameter and the requirement that the height of the wheel disc should be uniform. (This step aims at to attain the dimensional precision requirement of products, which the spin-forming technology can not achieve).
[0006] d. Punching a center hole and screw holes.
[0007] e. Punching hand holes (air holes) and then extruding the hand holes (air holes).
[0008] f. Reaming the spherical surfaces of the screw holes (or extruding the spherical surfaces of the screw holes).
[0009] g. Turning the center hole (or extruding the center hole).
[0010] h. Reshaping the flat surface and unifying the geometrical shape (for avoiding the out-of-roundness of the single air hole caused by irregular deformation during punching).
[0011] As shown in FIG. 2 and FIG. 3 , the existing spinning technology performs spinning on a work piece (circular blank) R with a spinning wheel P. The larger the spinning angle (α 1 +α 2 ) of the spinning technology, the larger the spinning gripping angle (α 3 +α 4 ) of the spinning wheel. Furthermore, the smaller the gripping angle, the stronger the extrusion force, therefore the extrusion force of the existing spinning technology is smaller. In addition, because the spinning explorator Q is cylindrical, and the forming method on the spinning explorator Q is an open type forming way without deformation size limitations, the well extrusion effect can not be achieved. Besides, fewer limitations on the spinning forming method and nonuniformity of the materials will result in instability of the spinning wheel P along with the changes in resistance during the movements of spinning wheel P, which cause small deformation on hard portion of the material whereas large deformation on soft portion, so micro-uneven conditions in the axial direction and the circumferential direction of the wheel disc will be brought about, and consequently the unbalance of the wheel disc. On the other hand, turning of the excircle will generate turning eccentricity, which can also further increase the unbalance of the wheel disc, as a result the precision of the excircle of the formed product can not meet the matching dimensional precision, and the spinning ring is retained on the formed product, which makes excircle processing in the vertical lathe is indispensable. Furthermore, because of the unevenness of the height of formed product due to the material nonuniformity, turning of the end surface is necessary. Thus it can be seen, the only way to improve the spinning efficiency is to increase the number of the vertical lathes and the number of staffs. However, the production cost is also increased.
SUMMARY OF THE INVENTION
[0012] The invention aims at providing a rolling forming method of wheel disc for improving the precision, strength and the speed of the disc forming.
[0013] The technical principle of the invention is as follows: The inventor invents a rolling forming method of the wheel disc against the defects in the existing spinning forming method of the wheel disc. During the rolling forming process, the compression area of the rolled blank is large and the rolling force is stronger than the existing spinning force. In addition, during the rolling forming process, a rolling explorator plays a role in limiting the outer diameter of the formed disc and the deformation resistance is further generated in order to enable the blank to be extruded and make precise deformation of the blank.
[0014] The purpose of the invention is achieved in this way: A rolling forming method of wheel disc comprises the following steps:
[0015] (1) Baiting a circular blank;
[0016] (2) Placing the circular blank in a cavity of a circular rolling explorator; and adopting at least two rolling wheels symmetrically arranged along the circumferential direction of the rolling explorator to perform planar synchronous staggered rolling on the circular blank in the cavity of the rolling explorator, in order to roll the circular blank into a wheel disc blank which gradually becomes thinner from the center to the rim; (The planar rolling refers to the situation that the rolling trajectories of the rolling wheels are always in a plane. The synchronous rolling refers to the situation that the rolling motions of the at least two rolling wheels are synchronous in order to ensure the uniform quality of the rolled surface of the circular blank. The staggered rolling refers to the situation that the rolling wheels are disposed mutually staggered in their initial positions in order to prevent the rolling trajectories of the rolling wheels on the surface of the circular blank from coinciding to ensure the surface of the circular blank compact. In other words, the more the rolling wheels is disposed, the more compact the rolling traces on the surface of the circular blank become, the better the quality of the surface is achieved. However, the factors of economic cost and stress state should be taken into account while determining the amount of the rolling wheels.)
[0017] (3) Performing trimming and sizing on the wheel disc blank;
[0018] (4) Stretching the wheel disc blank to form a wheel disc to meet the shape requirements of the section of the wheel disc and the dimensional requirements of the outer diameter and the height of the wheel disc.
[0019] Preferably, the rolling motions of the at least two rolling wheels in the step (2) comprise feed motions of the at least two rolling wheels in a horizontal direction and a rotation of each rolling wheel.
[0020] Preferably, the feed motion of each rolling wheel in the step (2) is controlled by a rolling wheel feeding mechanism connected with an electric control system, wherein the electric control system controls the feed rate and the feed amount of each rolling wheel feeding mechanism respectively thereby to further control the feed rate and the feed amount of each rolling wheel.
[0021] Preferably, the rotation of each rolling wheel in the step (2) is driven by a rolling wheel driving element connected with each rolling wheel respectively. Each rolling wheel driving element is connected with and controlled by an electric control system. The rolling wheel driving element drives each rolling wheel to generate an initial rotational speed respectively so as to prevent the rolling wheel from damage caused by excessive friction force generated between the rolling wheel and the circular blank at the very beginning of rolling. Once the rolling wheel starts to roll the circular blank, the driving force of the rolling wheel will not be supplied by rolling wheel driving element any more, but supplied by the friction force, which causes the servo of rolling wheel generated by rolling contact between the rolling wheel and the circular blank.
[0022] Preferably, the rolling forming method of the wheel disc further comprises the step (5): processing a center hole, screw holes, hand holes and the spherical surfaces of the screw holes on the formed wheel disc.
[0023] Preferably, the section of the cavity of the rolling explorator adopted in the step (2) is an equal-strength section, and the shape of the cavity of the rolling explorator corresponds to the shape of the wheel disc.
[0024] Preferably, in the step (1), the center hole is punched on the circular blank to position the circular blank in the cavity of the rolling explorator after cutting the circular blank.
[0025] Preferably, in the step (3), performing trimming and sizing on the wheel disc blank in a blanking method.
[0026] Preferably, in the step (4), stretching the wheel disc blank in dwell method in order to make the outer diameter dimension of the formed wheel disc precise.
[0027] The step (2) is implemented by a rolling forming machine. The rolling forming machine used for rolling the circular blank comprises:
[0028] A frame configured as a support structure of the whole rolling forming machine;
[0029] A lower rotating head assembly fixed on the frame; An actuating mechanism of the lower rotating head assembly connected with the lower rotating head assembly;
[0030] An electric control system connected with the actuating mechanism of the lower rotating head assembly;
[0031] A disc-like rolling explorator, the bottom of which is fixed to the lower rotating head assembly, having a cavity which could be formed into various shapes depending on the shapes of workpieces to be machined;
[0032] At least two rolling wheel units symmetrically arranged along the circumferential direction of the rolling explorator, wherein each rolling wheel unit comprises a rolling wheel which performs rolling motions in the cavity; the number of the rolling wheel unit can also be three, four or even more. The symmetrical arrangement of the rolling wheels aims at balancing the unbalanced radial force generated during the rolling deformation process of the workpieces. The symmetrical arrangement can greatly offset the unbalanced deformation force and prolong the service life of the rolling forming machine.
[0033] An upper rotating head assembly connected with a feed mechanism of the upper rotating head assembly to compress the rolling explorator under the drive of the feed mechanism of the upper rotating head assembly connected with the electric control system;
[0034] At least two rolling wheel feeding mechanisms correspondingly connected with the rolling wheel units and vertically connected with the feed mechanism of the upper rotating head assembly to drive the horizontal synchronous motions of the rolling wheels under the control of the electric control system.
[0035] Preferably, each rolling wheel unit is further correspondingly connected with a rolling wheel driving element connected with the electric control system. The purpose of arranging the rolling wheel driving element is to impart an initial rotational speed to the rolling wheel at the beginning of rolling forming in order to avoid damage of the rolling wheel caused by the excessive friction force between the rolling wheel and the workpiece when the rolling wheel enters into the rolling working position.
[0036] Preferably, a center hole is arranged at the center of the rolling exploratory and is coupled to the upper rotating head assembly. The center hole is used together with the upper rotating head assembly for positioning role so as to prevent workpiece from slipping in the cavity.
[0037] Preferably, the electric control system comprises: A plurality of displacement sensors correspondingly arranged on the feed mechanism of the upper rotating head assembly and each rolling wheel feeding mechanism respectively; A control PLC (programmable logic controller) connected with each displacement sensors respectively for performing data exchange with all of the displacement sensors; A plurality of proportional valves connected with the control PLC and correspondingly connected with the feed mechanism of the upper rotating head assembly and each rolling wheel feeding mechanism respectively for correspondingly controlling the feed rate of the feed mechanism of the upper rotating head assembly and each rolling wheel feeding mechanism respectively.
[0038] The electric control system can adjust the feed amount and the feed rate of the upper rotating head assembly depending on the factors such as the thickness of the circular blank in order to ensure the compaction of the circular blank. And the electric control system can further precisely control the horizontal feed rate and the horizontal feed amount of each rolling wheel during the rolling process, in order to control the circular blank to deform steady according to the precision requirements of the product and enable the shape of the formed variable section to meet the requirements of dimensional precision.
[0039] Preferably, each rolling wheel unit further comprises: A hollow sliding block correspondingly fixed to each rolling wheel feeding mechanism; A rotating shaft arranged in the hollow sliding block, wherein one end of the rotating shaft is correspondingly connected with each rolling wheel respectively and the other end of the rotating shaft is correspondingly coupled to a rolling wheel motor.
[0040] Preferably, a cross beam with at least two horizontally arranged sliding slots is further arranged between the upper rotating head assembly and the feed mechanism of the upper rotating head assembly. The rolling wheel feeding mechanisms are arranged over the cross beam. And the sliding blocks correspondingly slide along the sliding slots. The sliding slots and the corresponding sliding blocks on the cross beam play a well guiding role of the rolling wheels in the horizontal direction in order to enable the horizontal feed trajectories of the rolling wheels to be more precise and more stable.
[0041] Preferably, the frame comprises:
[0042] A base, on which the lower rotating head assembly is fixedly mounted;
[0043] At least four columns symmetrically vertically arranged on the base;
[0044] An upper box fixed on the upper ends of all the columns and coupled to the feed mechanism of the upper rotating head assembly.
[0045] Preferably, each rolling wheel feeding mechanism comprises:
[0046] A hydraulic cylinder fixed to the feed mechanism of the upper rotating head assembly vertically;
[0047] A connector with a horizontally arranged threaded hole coupled to a positioning bolt, wherein one end of the connector is fixed to the piston rod of the hydraulic cylinder, the other end of the connector is fixed to each sliding block correspondingly, the threaded hole and the corresponding positioning bolt are used for positioning the horizontal position of the rolling wheel unit.
[0048] Preferably, the feed mechanism of the upper rotating head assembly is a hydraulic cylinder assembly, and the actuating mechanism of the lower rotating head assembly is a hydraulic motor.
[0049] Preferably, each rolling wheel unit further comprises a spray cooling device which is connected with the electric control system. The spray cooling devices sprays cooling lubricating liquid towards the circular blank and each rolling wheel during the rolling process to avoid heating-up and abrasion of the surfaces of the circular blank and the rolling wheels.
[0050] The working process of the rolling forming machine is as follows:
[0051] 1) Loading: Positioning the circular blank with a punched center hole into the cavity of the rolling explorator.
[0052] 2) The feed mechanism of the upper rotating head assembly is driving the upper rotating head assembly towards the circular blank in order to compress it and driving the rolling wheel units to descend synchronously under the control of the electric control system.
[0053] 3) The actuating mechanism of the lower rotating head assembly drives the lower rotating head assembly to rotate and simultaneously drives the rolling explorator and the circular blank to rotate together under the control of the electric control system, thus the upper rotating head assembly rotates together with the circular blank.
[0054] 4) The rolling wheel driving element imparts an initial rotational speed to each rolling wheel under the control of the electric control system, and the rolling wheel feeding mechanism simultaneously drive each rolling wheel unit to feed horizontally under the control of the electric control system, so as to enable the rolling wheel unit to slowly enter into the space above the circular blank for rolling, wherein the initial feed amounts of the rolling wheels in the horizontal direction are staggered arranged, that is, the initial rolling trajectories of the at least two rolling wheels on the surface of the circular blank are not coincident. However, the feed increments are synchronous and constant during the whole rolling process. Such process will produce a high-quality rolled wheel disc with a fine grained surface.
[0055] 5) The feed mechanism of the upper rotating head assembly drives the upper rotating head assembly to depart from the wheel disc blank and drive the rolling wheel units to ascend simultaneously under the control of the electric control system. The electric control system further controls the lower rotating head assembly to stop rotating.
[0056] The invention of rolling forming method is a planar rolling forming process which refers to the process with little cutting amount or without cutting amount. The circular blank is formed in the cavity of the rolling explorator in the way of rolling and extruding. The shape of the cavity could be various surfaces, for example, a circular plane, a circular inclined plane, a circular corrugated surfaces or a circular wave surface. The workpiece produced by the method is more compact in structure, higher in strength, lighter in weight, lower in material consumption, and lower in energy consumption (energy consumption can be saved by above 80% in comparison with hot die forging). Besides, the production efficiency will be multiplied several times.
[0057] Comparing with the prior art, the rolling forming method of wheel disc has advantages and positive effects as follows:
[0058] (1) The force acting on the workpiece is stronger and the deformation precision of the workpiece blank is better because the rolling explorator will limit the deformation of the workpiece (different from the open type forming way in a spinning explorator) in the rolling forming process, and then generate a deformation resistance which will extrude the workpiece blank.
[0059] (2) The bending fatigue life of the workpiece produced with the same material can be greatly prolonged. The bending fatigue test of the wheel disc has proved that the service life of the workpiece can be prolonged by 30%, and the bending fatigue life of the product rolling formed with the 380 material (380 is the tensile strength of the material) can achieve the bending fatigue life of the product spinning formed with the 420 material (420 is the tensile strength of the material).
[0060] (3) The rolling forming method is a kind of coercive forming method, which limits the deformation of the workpiece in large scale. The invention can precisely form various geometric sections with the gradual deformation depending on the shape of the cavity of the rolling explorator. The formed product has a uniform mass in the axial direction and the circumferential direction, and has a high dynamic balance precision.
[0061] (4) The invention can produce a workpiece with high forming precision, therefore after the rolling step, just stamping, trimming and forming steps need to be performed to meet the 5 precision requirements of outer circle and the height of the end surface of the workpiece. And because the stamping rate and the stamping efficiency are much higher than the existing turning rate and turning efficiency, the invention will greatly improve the production efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0062] The following figures is used for explain the invention in detail with corresponding embodiment.
[0063] FIG. 1 is a schematic diagram of the spinning process of the wheel disc;
[0064] FIG. 2 is a schematic diagram of spinning motion state;
[0065] FIG. 3 is a view of FIG. 2 from the A-direction.
[0066] FIG. 4 is a schematic diagram of the structure of rolling forming machine adopted in an embodiment of the invention;
[0067] FIG. 5 shows the structure of the cross beam of the rolling forming machine adopted in an embodiment of the invention;
[0068] FIG. 6 is a schematic diagram of the rolling forming process of the invention;
[0069] FIG. 7 is a schematic diagram of rolling motion state;
[0070] FIG. 8 is a view of FIG. 7 from the A-direction;
[0071] FIG. 9 shows a top view of the cavity of rolling explorator in one shape in the invention;
[0072] FIG. 10 is a top view of the cavity of rolling explorator in another shape in the invention;
[0073] FIG. 11 is a top view of the cavity of rolling explorator in further another shape in the invention.
NUMERAL REFERENCES
[0074] P spinning wheel
[0075] Q spinning explorator
[0076] R circular blank
[0077] 1 frame
[0078] 11 base
[0079] 12 column
[0080] 13 upper box
[0081] 2 lower rotating head assembly
[0082] 3 actuating mechanism of lower rotating head assembly (hydraulic motor)
[0083] 4 rolling explorator
[0084] 41 cavity
[0085] 42 center hole
[0086] 5 rolling wheel unit
[0087] 51 rolling wheel
[0088] 52 sliding block
[0089] 53 rotating shaft
[0090] 6 upper rotating head assembly
[0091] 7 feed mechanism of upper rotating head assembly (hydraulic cylinder assembly)
[0092] 8 rolling wheel feeding mechanism
[0093] 81 hydraulic cylinder
[0094] 82 connector
[0095] 821 threaded hole
[0096] 83 positioning bolt
[0097] 9 hydraulic motor of rolling wheel
[0098] 10 cross beam
[0099] 101 sliding slot
[0100] 102 column hole
[0101] 103 center hole of cross beam
[0102] 104 side hole
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0103] The present invention will become more fully understood from the following detail description and the accompanying figures.
[0104] A rolling forming machine shown in FIG. 4 and FIG. 5 is adopted for rolling forming in this embodiment. The rolling forming machine comprises a frame 1 which is configured as a 10 support structure of the whole rolling forming machine. The frame 1 comprises a base 11 , four columns 12 symmetrically vertically mounted on the base 11 and an upper box 13 fixed on the upper ends of four columns. The rolling forming machine further comprises a lower rotating head assembly 2 fixed on the base 11 of the frame 1 ; an actuating mechanism of lower rotating head assembly 3 (hydraulic motor) coupled to the lower rotating head assembly 2 ; a disc-like 15 rolling explorator 4 with a cavity 41 having a center hole 42 at its center area, wherein the bottom of rolling explorator 4 is fixedly connected with the lower rotating head assembly 2 ; an upper rotating head assembly 6 connected with a feed mechanism of the upper rotating head assembly 7 (In this embodiment, the feed mechanism of the upper rotating head assembly 7 is a pair of hydraulic cylinders); two rolling wheel units 5 symmetrically arranged along the 20 circumferential direction of the rolling explorator 4 , wherein each rolling wheel unit 5 comprises a rolling wheel 51 , a rotating shaft 53 coupled to the rolling wheel 51 and arranged in a hollow sliding block 52 thereby coupled to a rolling wheel feeding mechanism 8 through the sliding block 52 ; a spray cooling device; and a hydraulic motor 9 of the rolling wheel correspondingly connected with the rotating shaft 53 (the hydraulic motor 9 of the rolling wheel 25 is arranged as the rolling wheel driving element); Two rolling wheel feeding mechanisms 8 correspondingly connected with two rolling wheel units 5 so as to drive two rolling wheel 51 to move horizontally and synchronously, and vertically connected with the feed mechanism of the upper rotating head assembly 7 , wherein each rolling wheel feeding mechanism 8 comprises a hydraulic cylinder 81 vertically fixed to the feed mechanism of the upper rotating head 30 assembly 7 , a connector 82 with a horizontally arranged threaded hole 821 coupled to a positioning bolt 83 for positioning the horizontal position of the rolling wheel unit 5 , wherein one end of the connector 82 is fixedly connected with the piston rod of the hydraulic cylinder 81 and the other end of the connector 82 is fixedly connected with each sliding block 52 through screws respectively in order to connect the sliding block 52 to the hydraulic cylinder 81 .
[0105] A cross beam 10 is arranged between the upper rotating head assembly and the feed mechanism of the upper rotating head assembly. All the rolling wheel feeding mechanisms are arranged above it. The cross beam 10 has two horizontally arranged sliding slots 101 , and the sliding blocks of the rolling wheel units slide along the sliding slots 101 respectively. The sliding slots 101 and the corresponding sliding blocks can well guide the motion of the rolling wheels in the horizontal direction so as to make the horizontal feed trajectories of the rolling wheels more precise and more stable. The cross beam 10 has four column holes 102 used for arranging the cross beam 10 onto the columns. A center hole 103 on the cross beam 10 is used for arranging the upper rotating head assembly. A side holes 104 on the cross beam 10 is used for arranging one pair of the hydraulic cylinders acting as the feed mechanism of the upper rotating head assembly.
[0106] The feed mechanism of the upper rotating head assembly 7 , the actuating mechanism of lower rotating head assembly 3 , each rolling wheel feeding mechanism 8 , the spray cooling device and the hydraulic motor 9 of rolling wheel are connected with and controlled by an electric control system respectively. The electric control system comprises a plurality of displacement sensors correspondingly arranged on the feed mechanism of the upper rotating head assembly and each rolling wheel feeding mechanism respectively; a control PLC (programmable logic controller) connected with each displacement sensors respectively for performing data exchange with all of the displacement sensors; a plurality of proportional valves connecting the control PLC and correspondingly connected with the feed mechanism of the upper rotating head assembly and each rolling wheel feeding mechanism respectively for correspondingly controlling the feed rate of the feed mechanism of the upper rotating head assembly and each rolling wheel feeding mechanism respectively.
[0107] The electric control system can adjust the feed amount and the feed rate of the upper rotating head assembly depending on the factors such as the thickness of the circular blank, in order to ensure the compaction of the circular blank. And the electric control system can further precisely control the horizontal feed rate and the horizontal feed amount of each rolling wheel during the rolling process in order to further control the circular blank to deform steady according to the precision requirements of the product and enable the shape of the formed variable section to meet the requirements of dimensional precision.
[0108] The working process of the rolling forming machine is as follows:
[0109] 1) Loading: Positioning the circular blank into the cavity of the rolling explorator.
[0110] 2) The feed mechanism of the upper rotating head assembly is driving the upper rotating head assembly to feed towards the circular blank in order to compress it and is driving the rolling wheel units to descend synchronously under the control of the electric control system.
[0111] 3) The actuating mechanism of the lower rotating head assembly drives the lower rotating head assembly to rotate and simultaneously drives the rolling explorator and the circular blank to rotate together under the control of the electric control system, thus the upper rotating head assembly rotates together with the circular blank.
[0112] 4) The rolling wheel driving element imparts an initial rotational speed to each rolling wheel under the control of the electric control system, and the rolling wheel feeding mechanism simultaneously drive each rolling wheel unit to feed horizontally under the control of the electric control system, so as to enable the rolling wheel unit to slowly enter into the space above the circular blank for rolling, wherein the initial feed amounts of the rolling wheels in the horizontal direction are staggered arranged, that is the initial rolling trajectories of the at least two rolling wheels on the surface of the circular blank are not coincident. However, the feed increments are synchronous and constant during the whole rolling process. Such process will produce a high-quality rolled workpiece with a fine grained surface.
[0113] 5) The feed mechanism of the upper rotating head assembly drives the upper rotating head assembly to depart from the wheel disc blank and drive the rolling wheel units to ascend simultaneously under the control of the electric control system. The electric control system further controls the lower rotating head assembly to stop rotating.
[0114] It should be understood that the rolling forming machine described above is merely an equipment for performance the rolling actions of the rolling wheels in the step (2), and it should not be considered as the limitations on the rolling forming method of the invention.
[0115] The steps of the rolling forming method of wheel disc in this embodiment are shown in FIG. 6 :
[0116] (1) Baiting a circular blank and punching a center hole at the center of the circular blank.
[0117] (2) Positioning the circular blank with the centre hole, and the rolling wheels starting rolling on the plane of the circular blank. The rolling angle α 5 shown in FIG. 7 and the rolling griping angle α 6 shown in FIG. 8 are constant during the rolling process. Two rolling wheels 51 are symmetrically arranged above the processing plane of the circular blank R along the circumferential direction of the rolling explorator 4 . Rolling the circular blank R into a wheel disc blank with the rolling wheels 51 in the cavity of the rolling explorator in order to make the wheel disc blank gradually become thinner from the centre to the rim. The rolling process is described as above.
[0118] The cavity of the rolling explorator can be formed into various shapes depending on the shapes of workpieces in order to meet various demanding requirements.
[0119] FIG. 9 shows a top view of the cavity of rolling explorator 4 in one shape. The salient circles shown in the figure are for the circular holes on the wheel disc. Placing the circular blank into the cavity shown in the figure and rolling the upper surface of the circular blank with the rolling wheels. The salient parts of the rolled circular blank are very thin, hence the holes on the wheel disc can be formed by lightly knocking off or punching the salient parts merely, which is quite simple and convenient.
[0120] FIG. 10 shows a top view of the cavity of rolling explorator 4 in another shape.
[0121] FIG. 11 shows a top view of the cavity of rolling explorator 4 in further another shape. It can be seen that the shape of the cavity of the rolling explorator 4 can be changed depending on the desired shape of the workpiece from FIG. 9 to FIG. 11 . It should be understood that the shapes of the cavity of the rolling explorator in the invention could be various, and the shapes shown in FIG. 9 to FIG. 11 are merely three embodiments which can not be considered as the limitations on the invention.
[0122] After rolling forming process described above, the wheel disc blank has a uniform mass along the circumferential direction and has a high dynamic balance precision, so the outer circle of the wheel disc blank does not need to be further processed on a vertical lathe. The precision of the end surface of the outer circle can be ensured by moulds, as long as following steps will be performed:
[0123] (3) Performing trimming and sizing on the wheel disc blank in a blanking method.
[0124] (4) Stretching the wheel disc blank in dwell method with a blank holder.
[0125] (5) Blanking the center hole and screw holes.
[0126] (6) Blanking hand holes and then extruding them.
[0127] (7) Reaming the spherical surface of the screw holes.
[0128] (8) Turning the center hole.
[0129] As shown in FIG. 2 , FIG. 3 , FIG. 7 and FIG. 8 , the forming forces, the deformation ways of the blanks and the results are different between the rolling forming method of the invention and the spinning forming method. The spinning deformation force, which makes the blank stretch in the forming process of the wheel disc, is smaller than the rolling deformation force. During the rolling forming process, the stress area of the blank is larger, the force is stronger and the blank is extruded in the explorator, which generates a yield deformation of the blank. The reason for that the deformation forces are different between the rolling forming method and the spinning forming method is that the angles in these two forming ways are different. The rolling angle α 5 is smaller than the spinning angle (α 1 +α 2 ) (the smaller the angle, the stronger the force), and the rolling gripping angle α 6 (i.e. the gripping angle of the rolling wheel 51 ) of the rolling wheel 51 is smaller than the spinning gripping angle (α 3 +α 4 ) of the spinning wheel (the smaller the rolling gripping angle, the stronger the extruding force), therefore the rolling force in the invention is much stronger than the spinning force.
[0130] The inventor adopts the rolling forming method of the invention to form wheel disc products with 380 material, and then performs bending fatigue tests on the wheel disc products. The results of the bending fatigue tests show that cracks occur in the wheel disc products (i.e. the wheel disc products are damaged) after above 1.5 million tests, and the wheel disc products are still intact after 1.2 million tests.
[0131] In order to contrast with the effect of rolling forming method of the invention, the inventor also adopts the spinning forming method to form wheel disc products with 380 material, and then also performs bending fatigue tests on the wheel disc products. The results of the bending fatigue tests show that the wheel disc products are generally damaged after about 1 million tests.
[0132] It can be seen that the rolling forming method of the invention is shorter in processing time, higher in production efficiency, higher in product precision and larger in bending fatigue strength comparing with the existing spinning forming method.
[0133] The above description is merely embodiments in nature and is in no way intended to limit the invention, its application, or use. | The invention provides a rolling forming method of wheel disc, which comprises the following steps: (1) Baiting a circular blank; (2) placing the circular blank in a cavity of a rolling explorator and adopting at least two rolling wheels symmetrically arranged along the circumferential direction of the rolling explorator to perform planar synchronous staggered rolling on the circular blank in the cavity of the rolling explorator; (3) performing trimming and sizing; and (4) stretch forming. The rolling forming method of wheel disc of this invention can precisely form various geometric sections with gradual deformation. The formed product has a uniform mass in the axial direction and the circumferential direction, and has a high dynamic balance precision. The invention can make the blank deform precisely, enhance the production efficiency, and reduce the cost, therefore the invention has good application and popularization prospect. |
FIELD OF THE INVENTION
This invention relates to write-read optical storage memory systems, and more particularly, to write once read many (WORM) memory systems having long retention life using an amorphous material such as diamond-like carbon, as the storage medium.
BACKGROUND OF THE INVENTION
The usual optical techniques for recording information on storage media is done by ablation of thin films with a focused laser beam. The thin film storage media using laser ablation may have very complicated structures, have low signal-to-noise ratios, require large amounts of laser energy, and suffer from degradation with time. Other optical techniques involve pit formation or bubbles in the thin film and in general require a surface deformation on the thin film to modify the optical properties of the active medium. One feature in common with all optical storage systems is the fact that optical storage systems utilize diffraction limited optics which is approximated by the wavelength of the laser light used to modify the material and to read the stored information from the storage media. As the wavelength of the laser light decreases, the optical spot size gets smaller, thus leading to higher bit density optical storage systems.
In U.S. Pat. No. 5,024,927 which issued on Jun. 18, 1991 to K. Yamada et al., an information recording medium capable of recording and erasing information with the application of electro-magnetic waves is described comprising a recording layer formed on a substrate, the recording layer including a carbon-based material, a polymer prepared by subjecting a pigment to plasma polymerization and an optically reversible material whose optical characteristics can be reversibly changed. The optically reversible material may be finally-divided particles of a metal dispersed in the carbon-based material. The carbon-based material serves as the matrix for the optically reversible material in the recording layer. Specific examples of the optically-reversible materials include chalcogens such as Te and Se, alloys of chalcogens, materials whose crystalline phase is optically changeable, such as Zn-Ag and Cu-Al-Ni, Phthalocyanine-type pigments whose crystalline phase is optically changeable, and organic chalcogen compounds prepared by plasma CVD, such as diphenyl tellurium, diphenyl selenium, dimethyl tellrurium, dimethyl selenium, tellurium diisopropoxy diacetylacetonate and selenium diisopropoxy diacetylacetonate.
In U.S. Pat. No. 4,812,385 which issued on Mar. 14, 1989 to K. C. Pan, a write once read many (WORM) optical memory system is described. A recording laser provides a laser beam through a series of lenses to be focussed as a spot on a rotating disk. The disk has a layer of amorphous thin film material thereon comprising an alloy having a composition within a polygon in a ternary composition diagram of antimony, zinc and tin. Writing is accomplished by heating a location above the transition temperature wherein the amorphous material is converted to a crystalline material. A separate laser is shown for reading data from the rotating disk by detecting the reflectance of the alloy in either the crystalline or amorphous state. The amorphous state is very stable.
It is well known that certain polymers may undergo an irreversible index of refraction change in response to irradiation of ultraviolet light. In U.S. Pat. No. 3,689,264 which issued on Sep. 5, 1972 to E. A. Chandross et al., readily observable irreversible index of refraction changes in poly (methyl methacrylate) sensitized by the addition of ingredients to enable photo-induced cross-linking was described when irradiated with ultraviolet light from a laser.
In U.S. Pat. No. 4,994,347 which issued on Feb. 19, 1991 to W. K. Smothers, a substantially solid, storage stable photopolymerizable composition is described that forms a refractive-index image upon exposure to actinic radiation. The composition consists essentially of: a solvent soluble, thermal plastic polymeric binder; N-vinyl carbazole; and a hexaarylbiimidazole photoinitiator system having a hydrogen donor component.
In U.S. Pat. No. 4,981,777 which issued on Jan. 1, 1991 to M. Kuroiwa et al., a thin optical recording film is described comprising at least one low melting point metal, carbon and hydrogen on a substrate, and heat treating the so formed film on the substrate at a temperature of from 70° to 300° C. for a period of at least 5 seconds. The heat treatment is carried out at a temperature well below the melting point of the low melting point metal contained in the film. It has been found that the recording sensitivity of the recording film can be enhanced by the heat treatment according to the invention. By the term "enhanced recording sensitivity", it is meant reduction in energy of an energy beam such as a laser light required for recording information in unit area of the recording film. The low melting point metal element in the recording film may be tellurium, bismuth, zinc, cadmium, lead and tin used alone or in combination. The carbon content of the recording film is preferably from 5 to 40 atomic percent based on the whole film.
In U.S. Pat. No. 4,647,512 which issued on Mar. 3, 1987 to N. Venkataramanan et al., a plasma assisted chemical vapor transport process is described. The material, diamond-like carbon may be produced by plasma assisted chemical vapor transport (PACVT) process in which hydrogen is employed as the reactive process feedgas and in which the deposition process is conducted in a controllably energetic ion bombardment of the surface on which the film of diamond-like carbon is grown. Further, FIG. 4 of '512 displays the optical transmission of diamond-like carbon films obtained on KBr substrates whose intrinsic transparency is also shown in FIG. 4. The films with a thickness of about 1/2 micrometer exhibit high transparency at UV wavelength. The films exhibit a transparency of more than 50% for wavelengths above about 200 nm and more than 90% above about 400 nm. The films also exhibit a high index of refraction, about 2 at 850 nm.
The use of diamond-like carbon film as a protective coating on magnetic media has been described in U.S. Pat. No. 4,647,494 which issued on Mar. 3, 1987 to B. S. Meyerson et al. and assigned to the assignee herein. The diamond-like carbon layer provided a superior wear-resistant coating over the metallic magnetic recording layers. An intermediate layer of silicon having a minimum thickness of a few atomic layers was formed between the diamond-like carbon protective layer and the metallic magnetic recording layer to provide strong adhesion. The diamond-like carbon layer was plasma deposited.
In U.S. Pat. No. 4,833,031 which issued on May 23, 1989 to H. Kurokawa et al., a protective film was described made of a diamond-like carbon film and an organic compound film over a ferromagnetic metal recording film. The protective film provided excellent durability and small spacing loss and as a result high density magnetic recording was obtainable. The organic film on the amorphous carbon film included an organic compound having at least one fatty alkyl group having at least 8 carbon atoms at the end of a molecular structure thereof.
In a publication by A. Grill et al. entitled, "Bonding, interfacial effects and adhesion in DLC", SPIE, Vol. 969, Diamond Optics (1988), the structure and optical properties of diamond-like carbon (DLC) films are described. Diamond-like carbon films may contain sp 2 , sp 3 and even sp 1 coordinated carbon atoms in a disordered network. The ratio between the carbon atoms in the different coordinations of carbon atoms is to a great extent determined by the hydrogen content of the films. Typically, diamond-like carbon layers are seen to be weakly absorbing in the visible spectrum, tending toward transparent in the infrared spectrum. Their transparency makes diamond-like carbon films good candidates as a protective optical coating.
In a publication by V. Y. Armeyev et al. entitled, "Direct laser writing of conductive pathways into diamond-like carbon films", SPIE, Vol. 1352, Laser Surface Microprocessing, pp. 200, (1989), microprocessing of diamond-like carbon films with a continuous wave argon laser at 488 nm wavelength was described. Conductive lines were formed in the amorphous carbon films several micrometers wide having a resistivity of about 4×10 -2 Ωcm. The conductive lines were formed by graphitization as evidenced by Raman spectroscopy. The graphitization temperature threshold lies in the range from 400° to 500° C. The etching threshold where carbon is oxidized is found in the temperature range near 600° C. The use of diamond-like carbon as the active material for once-write optical recording is suggested, if the change in reflectance due to local graphitization is high enough. By using a finely focused He-Ne laser beam at 0.633 nm, the contrast in reflectivity was about 2 for scanning a graphitized spot against the as-deposited film. The graphitized strip was written at a power of 740 milliwatts.
In a publication by S. Prawer et al. entitled, "Pulsed laser treatment of diamond-like carbon films", Appl. Phys. Lett. 48, 1585 (1986), conducting pathways having a resistance of 0.10 Ωcm were formed in insulating (10 6 Ωcm) diamond-like carbon film using pulsed laser irradiation at 0.53 micrometer. Below a laser intensity threshold of 0.2 J/cm 2 of a pulsed, 70 ns, neodymium: yttrium aluminum garnet operating at 0.53 micrometers, there was no observable interaction between the laser and the film. Above 0.2 J/cm 2 , the diamond-like carbon film was partially graphitized and the effected region displayed a terrace-like structure with sharp edges. Two processes were described resulting from the interaction of the laser with the diamond-like carbon film. The diamond-like carbon film was transformed into a form of graphite for laser intensities exceeding a threshold of about 0.2 J/cm 2 and ablation of the graphite occurs.
In a publication by M. Rothschild et al. entitled, "Excimer-laser etching of diamond and hard carbon films by direct writing and optical projection", J. Vac. Sci. Technol. B, 4, 310 (1986), diamond-like carbon thin films were explored as positive-acting resist for semiconductor patterning. An ArF laser at 193 nm wavelength, was particularly suitable for interaction with diamond-like carbon, since the proton energy at this wavelength 6.4 eV is higher than the bandgap of diamond 5.4 eV. The crystal was highly absorptive. Crystalline diamond and diamond-like carbon thin films were etched with the Excimer laser. Deep structures, about 15 micrometers, were obtained in the direct write configuration and linewidths less than the laser wavelengths were generated in optical projection. The laser-induced etching takes place via surface graphitization, by a combined thermal/photochemical conversion, followed by sublimation and/or reaction.
In a publication by R. J. Gambino et al. entitled, "Spin resonance spectroscopy of amorphous carbon films", Solid State Comm., Vol. 34, pp. 15-18 (1980), printed in Great Britain, amorphous carbon was prepared by the plasma decomposition of propane providing a film which was hard, transparent, insulator much like diamond in its physical properties. The composition of amorphous carbon is described as being a random network of sp 3 and sp 2 bonded carbon with the relative fraction of each depending on the method of preparation and the process parameters.
SUMMARY OF THE INVENTION
In accordance with the present invention, a method and apparatus for storing data is described comprising the steps of: selecting an amorphous solid having atoms therein covalently bonded together, for example, diamond-like carbon, silicon carbide, boron carbide, boron nitride, amorphous silicon and amorphous germanium having a first index of refraction, and heating the amorphous solid in predetermined areas to change the index of refraction in the heated areas to a second index of refraction, the selected amorphous solid having a plurality of covalent bonds which may be modified by heating to a predetermined temperature without melting or crystallizing the amorphous solid.
It is an object of the invention to use a focussed optical or laser beam to provide a heat source to heat an amorphous solid in a localized area.
It is a further object of the invention to provide an amorphous to an amorphous transformation of a selected solid, for example, diamond-like carbon.
It is a further object of the invention to utilize diamond-like carbon as the amorphous solid and to provide a transformation of some covalent bonds from sp 2 to sp 3 whereby the density of the amorphous solid increases thereby changing the index of refraction of the material.
It is a further object of the invention to perform an amorphous to amorphous transformation of the covalently bonded material without melting the material or forming crystals therein so as to form a crystalline material.
It is a further object to provide a second stable state of amorphous material from a first state having a mixture of sp 2 and sp 3 bonds by converting sp 2 bonds to sp 3 bonds in the covalently bonded material.
It is a further object of the invention to select carbon as the amorphous material having substantially sp 3 diamond type bonding.
It is a further object of the invention to provide localized heating of a covalently bonded amorphous solid to convert sp 2 bonds to sp 3 bonds as a function of the thermal energy deposited in the localized area.
It is a further object of the invention to provide an amorphous to amorphous transformation in covalently bonded material wherein the density of the material changes resulting in a change of the index of refraction, which in turn produces a change in reflectance.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, objects, and advantages of the present invention will become apparent upon a consideration of the following detailed description of the invention when read in conjunction with the drawing, in which:
FIG. 1 shows a graph of the index of refraction versus the anneal temperature of several diamond-like carbon films;
FIG. 2 shows diamond-like carbon film patterned with an Excimer laser at 248 nm;
FIG. 3 shows one embodiment of the invention; and
FIG. 4 is a cross-section view along the line 4--4 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, FIG. 1 shows a graph of the index of refraction versus the anneal temperature of several diamond-like carbon films. In FIG. 1, the ordinate represents the index of refraction and the abscissa represents the temperature in degrees Celsius. The diamond-like carbon films used for generating the data in FIG. 1 were formed by plasma assisted chemical vapor deposition (PACVD). Curve 12 represents data from a diamond-like carbon film deposited at a substrate temperature of 100° C. with a substrate bias voltage of -80 volts. As can be seen in FIG. 1, as the anneal temperature of a selected area of the film increases, the index of refraction likewise increases. Curve 14 shows data obtained from a diamond-like carbon film deposited on a substrate at 250° C. with a substrate bias voltage of -80 volts. Curve 16 represents data obtained from a diamond-like carbon film deposited at a substrate temperature of 250° C. with a substrate bias voltage of -150 volts. A substantial change in the index of refraction is shown in FIG. 1 when the anneal temperature is raised to a temperature in the range from 450° C. to 600° C. A film deposited at a substrate temperature of 100° C. has an index of fraction of 1.9 and an index of refraction of 2.9 after experiencing an anneal temperature of 600° C. The large change in the index of refraction can be induced by local heating of the diamond-like carbon film using a focussed laser beam. A metal film or layer 64 shown in FIG. 4 may be deposited on the substrate or disc 48 prior to depositing layer 68 which may be a diamond-like carbon film to provide a thin metallic mirror by way of layer 64 below layer 68. The thickness of the diamond-like carbon film or layer 68, which may be in the range from 4 nm to 1,000 nm, may be selected for minimum reflection which should be a thickness of one quarter wavelength or a multiple of (2n+1) quarter wavelengths where n is an integer, for example about 30 nm. Information may be written into the diamond-like carbon film by local annealing of the diamond-like carbon film or layer 68 via a laser spot, or by projection of a plurality of spots, or by a suitable energy source which imparts thermal energy to the diamond-like carbon film or layer 68 which induces a change in the index of refraction of the diamond-like carbon film or layer 68 in the selected area, a change in reflectance and a change in layer 68 thickness.
After information is written into the diamond-like carbon film, the information may be read out many times which is described in more detail in reference to FIG. 3. A light beam 84 scans the diamond-like carbon film or storage media 50 as it moves below light beam 84 on disc 48 shown in FIG. 3 and detects the index of refraction or the reflectance such as by a laser beam 84 which is reflected from the metal mirror or layer 64, shown in FIG. 4, below the diamond-like carbon film or storage media 50 and from the diamond-like carbon film or storage media itself. The reflected beam, which is intensity modulated as it scans the diamond-like carbon film or storage media 50, may be detected or sensed by a photo diode and allows data to be read back from the storage media due to the different intensity levels of reflected light, due to the variation in the index of refraction of the unexposed and the exposed areas of storage media 50. The photo diode may be a quadrant detector to provide tracking information to a servo control loop for pointing light beam 84. Light beam 84 should be monochromatic light for focussing but does not need to be coherent. A non-laser light source that is monochromatic would be suitable.
FIG. 2 shows a diamond-like carbon film patterned with an Excimer laser at 248 nm. In FIG. 2, a thin film 20 of diamond-like carbon was deposited on a substrate 21 by plasma assisted chemical vapor deposition technique (rf or dc powered) with a thickness on the order of 60 nm. The feedgas supplied to the reactor was acetylene or cyclohexane or any other hydrocarbon gas or vapor. The pressure during PACVD was in the range from 30 to 300 m torr. Thin film 20 was low in hydrogen content. Thin film 20 typically contains 10 to 50 atomic percent hydrogen. A metal mask (not shown) having openings therein was placed over the thin film 20. Thin film 20 was exposed through openings in the metal mask to radiation at 248 nm from an Excimer laser with a sequence of 8 pulses, each pulse having an energy density of 133 mJ/cm 2 . Each laser pulse may have a pulse width in the range from 10 to 50 nanoseconds and a repetition rate of 1 hertz. It is believed that the diamond-like carbon film 20 is cooled down during the 1 second after each laser pulse. The laser pulse may have an energy density in the range from 100 to 200 mJ/cm 2 . By utilizing a wavelength from the laser of 248 nm, the minimum focussed spot size may be in a range from 0.3 to 0.5 micrometers. Therefore, the density of the data stored on respective areas of film 20 is controlled by the diffraction limited optics, i.e., the minimum spot size that may be focused. In FIG. 2, squares 22 through 29 show film 20 after being annealed by 8 pulses from an Excimer laser. Each square is approximately 600 micrometers on a side. Stripes 31 through 35 shown in FIG. 2 are parallel to one another, 50 micrometers wide and spaced apart from one another by 50 micrometers and about 700 micrometers long. The light contrast in unexposed film 37 which are light compared to squares 22-29 and strips 31 through 35 which are dark is the result of the change of the index of refraction of the respective film squares 22-29 and stripes 31-35 following 8 laser pulses having an energy density of 133 mJ/cm 2 per pulse. After exposure of film 20 by the laser through a melt mask positioned on film 20, the metal mask was removed.
The change in the index of refraction of the diamond-like carbon film 20 is believed to be due to converting sp 2 bonds to sp 3 bonds in the exposed material on film 20 which, in turn, increases the density of the material. Examples of covalently bonded solid material include amorphous semiconductors, for example, diamond-like carbon, silicon carbide, boron carbide, boron nitride, amorphous silicon, and amorphous germanium. The existence and quantity of covalent bonds sp 2 and or sp 3 may be measured by laser Raman spectroscopy and also by Electron Energy Loss spectroscopy. It is noted that in amorphous diamond-like carbon, the sp 2 bonds are relatively weak bonds and that the diamond-like carbon structure is a 3-dimensional structure with the sp 2 bonds and the sp 3 bonds being oriented at different angles with respect to the arrangement of the atoms.
FIG. 3 shows an optical storage memory system 40 comprising a memory control unit 42, a write laser 44, a read laser 46, a disc 48 having storage media 50, and a motor 52 for moving the storage media 50. Memory control unit 42 may receive data over lead 54 for writing into storage media 50. Memory control 42 functions in response to the write data lead 54 to provide control signals and write data on lead 56 to an input of write laser 44. Write laser 44 functions to provide a laser beam 58 which is directed through lens 59 to the upper surface 690 of disc 48 to write data into storage media 50. As shown in FIG. 3, lens 59 provides a focussed laser beam 61 focussed on surface 60 of disc 48. Alternatively, lens 59 may include means to project a pattern or a plurality of spots on upper surface 60 of disc 48 to write in data. In FIG. 3, focussed laser beam 61 may include means for scanning or positioning focussed laser beam 61 with respect to upper surface 60 or motor 52 may position a selected area of surface 60 underneath focussed laser beam 61.
Memory control unit 42 may control write signals such as pulse duration, pulse repetition, pulse power or energy to write laser 44.
FIG. 4 shows a cross-section view of disc 48 along the line 4--4 of FIG. 3. Disc 48 provides a mechanical substrate for supporting storage media 50. Disc 48 may be, for example, glass, aluminum, plastic, ceramic, silicon, or other suitable material. A metal layer 64 may be deposited on the upper surface of disc 48. Metal layer 64 functions to provide a mirror to reflect optical energy arriving at its upper surface 65. Metal layer 64 may be, for example, aluminum, gold, chromium, etc. A layer 66 is deposited on upper surface 65 which may be very thin, for example, a few angstroms to several thousand angstroms thick and functions to provide an adhesion layer between metal layer 64 and a layer 68 of amorphous material to be deposited above layer 66. Layer 68 is deposited over layer 66 and may be, for example, a covalently bonded solid material selected from the group consisting of diamond-like carbon, silicon carbide, boron carbide, boron nitride, amorphous silicon, amorphous germanium or the hydrogenated forms of such materials. Hydrogenated forms of such material may have up to 50 atomic percent hydrogen. The hydrogen is covalently bonded to the carbon. The material for layer 66 is selected to provide good adhesion to layer 68 and may be, for example, silicon. The thickness of layer 68 and 66 may be adjusted to provide a quarter wavelength thickness or a multiple quarter wavelength thickness for the intended light source used to receive the minimum reflected light for writing and reading or sensing the index of refraction or the reflectance of layer 68. Using a reflection minimum as the initial state or condition of the storage media reduces the laser power or light power needed to heat selected areas of the storage media to write information in the storage media.
As shown in FIG. 3, disc 48 is supported and rotated by spindle 72. Spindle 72 is supported by bearing 74 and rotated by motor 52. A control signal from memory control unit 42 over lead 76 functions to control through control signals motor 52. Control signals on lead 76 may direct motor 52 to start, spin up to a certain RPM, to slow down and to stop. Motor 52 may rotate at, for example, 3600 RPM or 1 revolution per second. Disc 48 may rotate clockwise as shown by arrow 78 about axis 80 which passes through the center of spindle 72.
Read laser 46 provides a laser beam 82 which is directed through lens 83 to surface 60 of disc 48. Lens 82 may provide a focussed laser beam 84 which is focussed on surface 60. Memory control unit 42 provides control signals over lead 86 to read laser 46. Memory control unit 42 may direct read laser 46 at appropriate times to read data from layer 68 on disc 48 and may provide signals for positioning a focussed laser 84 on disc 48 by a positioning means (not shown). Read laser 46 functions to generate laser beam 82 which may be low power, for example, in the range from 1 to 10 milliwatts if a continuous laser beam and 1 to 10 mJ per pulse if a pulsed laser beam and to contain means for detecting changes in the reflectance or index of refraction of layer 68 of storage media 50 by way of the reflected beam from layer 68 through lens 83 to read laser 46 or through another suitable lens to another photo detector, for example, a photo diode (not shown). The intensity of the reflected beam may vary which provides an indication of the reflectance or the index of refraction. Read laser 46 functions to provide a signal over lead 88 indicative of the data stored in layer 68 by the reflectance or the index of refraction of layer 68 obtained from the reflected laser beam 84. Lead 88 is coupled to an input of memory control unit 42 which in turn may process the data, if necessary, and provides an output signal on lead 92 indicative of the data stored on storage media 50 obtained from reflected laser beam 84.
The invention is applicable to all covalently bonded amorphous materials where an amorphous to amorphous transformation may be obtained with a material having a high enough crystallization or melting temperature so that the transformation is obtained without being overridden by crystallization of the material.
While the present invention has been shown and described with respect to specific embodiments, it is not thus limited. Numerous modifications, changes, and improvements will occur which fall within the spirit and scope of the invention. | A method and apparatus for storing data is provided incorporating an amorphous solid having covalent bonds and a first index of refraction and an energy source for thermally heating selected areas of the amorphous solid to change the index of refraction without melting or substantially crystallizing the amorphous solid. The invention overcomes the problem of corrosion, moisture, or microbial attack resulting in deterioration of the storage medium over time, i.e., 100 years. |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Non provisional U.S. Patent Application of U.S. Provisional Application No. 61/676,709, entitled “Rotor and Generator for Reducing Harmonics”, filed Jul. 27, 2012, which is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] The present invention relates generally to electric power generators, and more particularly to rotors used in such equipment.
[0003] Electrical power generators are used in a wide variety of applications throughout the industry. For example, such generators may be driven by engines, such as internal combustion engines to generate power needed for specific applications. In a particular type of application, involving welding, plasma cutting and similar operations, an electric motor drives a rotor within a stator of the generator to generate alternating current (AC) power. This power may be rectified into direct current (DC) power, and converted and conditioned in various ways for the final application. Generators of this type may serve specific purposes, such as for welding, plasma cutting and similar operations, or may be more general in purpose, such as for providing emergency or backup power, or for applications requiring power at locations remote from the conventional power grid availability.
[0004] Certain generators have been developed for these applications, including generators available commercially from Miller Electric Mfg. of Appleton, Wis., under the commercial designation Bobcat™ and Trailblazer®. Certain of these generators may include rotors with particular geometries adapted to reduce fluctuations in the power generated.
[0005] Despite these improvements, further refinement in generator design and manufacture are needed.
BRIEF DESCRIPTION
[0006] The present invention provides a generator and rotor design adapted to respond to such needs. In accordance with certain aspects of the invention, the rotor described employs a mechanism to reduce the currents induced in the rotor from the stator. The mechanism literally “shorts” the currents eliminating the voltage harmonics reflected back into the stator. Eliminating the harmonics improves the sinusoidal waveform creating a “cleaner” power for many applications. In accordance with certain embodiments, then, a rotor for an electrical generator, comprises a laminated core comprising a plurality of laminate plates stacked adjacent to one another, each laminate plate comprising a plurality of holes near a periphery thereof. Conductive end caps are disposed on front and rear sides of the laminated core, each of the end caps comprising a plurality of holes near a periphery thereof. A plurality of conductive rods extend through the holes in the laminate plates and the end caps, and secured to the end caps to form a damper cage. The laminated core and the damper cage are skewed along a length of the rotor.
[0007] The invention also provides an electrical generator that comprises a stator and a rotor disposed in the stator. The rotor conforms to the construction outlined above.
[0008] In accordance with other aspects, the invention comprises a method for making a rotor for an electrical generator. According to the method, a plurality of laminate plates are stacked, each laminate plate comprising a plurality of holes adjacent to a periphery thereof. Conductive end caps are disposed adjacent to front and rear sides of the stack of laminate plates, each of the end caps comprising a plurality of holes adjacent to a periphery thereof. Conductive rods are disposed in the holes of the laminate plates and the end caps. The stack of laminate plates, the end caps and the rods along a length of thereof are then skewed, and the rods are secured to the end caps.
DRAWINGS
[0009] These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[0010] FIG. 1 is a diagrammatical representation of an exemplary application for power conversion circuitry, in the form of a welding system;
[0011] FIG. 2 is a circuit diagram for a portion of the power conversion circuitry of FIG. 1 , particularly illustrating certain functional circuit components;
[0012] FIG. 3 is a diagrammatical representation of an exemplary generator coupled to an engine for use in a system of the type shown in FIG. 2 ;
[0013] FIG. 4 is a perspective view of a rotor of the machine as shown in FIG. 3 ;
[0014] FIG. 5 is an exploded view of certain components of the rotor of FIG. 4 ;
[0015] FIG. 6 is a further exploded view of certain of these components;
[0016] FIG. 7 is a top view of the rotor illustrating a skew in the rotor winding and core;
[0017] FIG. 8 is an end view of the rotor illustrating the skew;
[0018] FIG. 9 is an end view showing only the core and end caps of the rotor;
[0019] FIG. 10 is perspective view showing the core and end caps;
[0020] FIG. 11 shows a damper cage formed by rods and end caps of the rotor skewed as they will be positioned in the final rotor configuration; and
[0021] FIG. 12 is an end view showing the end caps and skew.
DETAILED DESCRIPTION
[0022] Turning now to the drawings, and referring first to FIG. 1 , an exemplary welding system 10 is illustrated that includes a power supply 12 for providing power for welding, plasma cutting and similar applications. The power supply 12 in the illustrated embodiment comprises an engine generator set 14 that itself includes an internal combustion engine 16 and a generator 18 . The engine 16 may be of any suitable type, such as gasoline engines or diesel engines, and will generally be of a size appropriate for the power output anticipated for the application. The engine will be particularly sized to drive the generator 18 to produce one or more forms of output power. In the contemplated application, the generator 18 is wound for producing multiple types of output power, such as welding power, as well as auxiliary power for lights, power tools, and so forth, and these may take the form of both AC and DC outputs. Various support components and systems of the engine and generator are not illustrated specifically in FIG. 1 , but these will typically include batteries, battery chargers, fuel and exhaust systems, and so forth.
[0023] Power conditioning circuitry 20 is coupled to the generator 18 to receive power generated during operation and to convert the power to a form desired for a load or application. In the illustrated embodiment generator 18 produces three-phase power that is applied to the power conditioning circuitry 20 . In certain embodiments, however, the generator may produce single phase power. The power conditioning circuitry includes components which receive the incoming power, converted to a DC form, and further filter and convert the power to the desired output form. More will be said about the power conditioning circuitry 20 in the discussion below.
[0024] The engine 16 , the generator 18 and the power conditioning circuitry 20 are all coupled to control circuitry, illustrated generally by reference numeral 22 . In practice, the control circuitry 22 may comprise one or more actual circuits, as well as firmware and software configured to monitor operation of the engine, the generator and the power conditioning circuitry, as well as certain loads in specific applications. Portions of the control circuitry may be centrally located as illustrated, or the circuitry may be divided to control the engine, generator and power conditioning circuitry separately. In most applications, however, such separated control circuits may communicate with one another in some form to coordinate control of these system components. The control circuitry 22 is coupled to an operator interface 24 . In most applications, the operator interface will include a surface-mounted control panel that allows a system operator to control aspects of the operation and output, and to monitor or read parameters of the system operation. In a welding application, for example, the operator interface may allow the operator to select various welding processes, current and voltage levels, as well as specific regimes for welding operations. These are communicated to a control circuitry, which itself comprises one or more processors and support memory. Based upon the operator selections, then, the control circuitry will implement particular control regimes stored in the memory via the processors. Such memory may also store temporary parameters during operation, such as for facilitating feedback control.
[0025] Also illustrated in FIG. 1 for the welding application is an optional wire feeder 26 . As will be appreciated by those skilled in the art, such wire feeders are typically used in gas metal arc welding (GMAW) processes, commonly referred to as metal inert gas (MIG) processes. In such processes a wire electrode is fed from the wire feeder, along with welding power and, where suitable, shielding gas, to a welding torch 28 . In other applications, however, the wire feeder may not be required, such as for processes commonly referred to as tungsten inert gas (TIG) and stick welding. In all of these processes, however, at some point and electrode 30 is used to complete a circuit through a workpiece 32 and a work clamp 34 . The electrode thus serves to establish and maintain an electric arc with the workpiece that aides in melting the workpiece and some processes the electrode, to complete the desired weld.
[0026] To allow for feedback control, the system is commonly equipped with a number of sensors which provide signals to the control circuitry during operation. Certain sensors are illustrated schematically in FIG. 1 , including engine sensors 36 , generator sensors 38 , power conditioning circuitry sensors 40 , and application sensors 42 . As will be appreciated by those skilled in the art, in practice, a wide variety of such sensors may be employed. For example, engine sensors 36 will typically include speed sensors, temperature sensors, throttle sensors, and so forth. The generator sensors 38 will commonly include voltage and current sensors, as will the power conditioning circuitry sensors 40 . The application sensors 42 will also typically include at least one of current and voltage sensing capabilities, to detect the application of power to the load.
[0027] FIG. 2 illustrates electrical circuitry that may be included in the power conditioning circuitry 20 illustrated in FIG. 1 . As shown in FIG. 2 , this circuitry may include the generator windings 44 , illustrated here as arranged in a delta configuration, that output three-phase power to a rectifier 46 . In the illustrated embodiment the three-phase rectifier is a passive rectifier comprising a series of diodes that provide a DC waveform to a DC bus 48 . Power on the DC bus is then applied to filtering and conditioning circuitry 50 which aide in smoothing the waveform, avoiding excessive perturbations to the DC waveform, and so forth. The DC power is ultimately applied to a switch module 52 , which in practice comprises a series of switches and associated electronic components, such as diodes. In welding applications, particular control regimes may allow for producing pulsed output, AC output, DC output, and particularly adapted regimes suitable for specific processes. As will be appreciated by those skilled in the art, various switch module designs may be employed, and these may use available components, such as insulated gate bipolar transistors (IGBTs), silicon controlled rectifiers (SCRs), transformers, and so forth. Many of these will be available in packaging that includes both the switches and/or diodes in appropriate configurations.
[0028] Finally, an output inductor 54 is typically used for welding applications. As will be appreciated by those skilled in the welding arts, the size and energy storage capacity of the output inductor is selected to suit the output power (voltage and current) of the anticipated application. Although not illustrated, it should also be noted that certain other circuitry may be provided in this arrangement, and power may be drawn and conditioned in other forms.
[0029] While only certain features of the exemplary systems have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. For example, in addition to the output terminals illustrated in FIG. 2 , power may be drawn from the DC bus for use in other conversion processes. This may allow for DC welding, for example, as well as for the supply of synthetic AC power for various auxiliary applications. The synthetic auxiliary power may be adapted, for example, for single phase power tools, lighting, and so forth. Where provided, such power may be output via separate terminals, or even conventional receptacles similar to those used for power grid distribution.
[0030] FIG. 3 illustrates certain functional components of the generator for use in a system of the type described above. As mentioned above, the engine 16 is coupled to a generator 18 to produce electrical power used for the welding, plasma cutting or other applications. The generator itself comprises a housing 58 in which a stator 58 is disposed. The stator is wound with stator windings (not shown) to produce the desired output upon rotation of a rotor 60 . The rotor comprises a shaft 62 that is supported by a bearing 64 . A coupling 66 serves to transmit rotational torch to the shaft of the generator as the engine is powered. Input signals 68 are provided to a generator, such as for excitation of the winding. Power signals 70 are received from the stator as the rotor is turned.
[0031] In a presently contemplated embodiment, multiple slots (not separately shown) are included in the rotor, which comprises a variety of windings used to generate the desired power. Specifically, in the illustrated embodiment the generator produces three-phase welding power output, single-phase auxiliary power output, three-phase synthetic AC power output, 24 volt output for powering a wire feeder, and includes a 200 volt excitation coil.
[0032] To reduce or remove slot harmonics that could be generated by the alignment of winding slots of the stator with winding slots of the rotor, the rotor is twisted or skewed as illustrated in FIG. 4 . Specifically, the rotor comprises a laminated core 72 illustrated as having a first side 74 and second side 76 . Windings 78 are disposed between these sides of the laminated core. The windings are separated from the core by non-conductive separators 80 . As described more fully below, a damper cage 82 is defined by a front end cap 84 and a rear end cap 86 (see, e.g., FIG. 6 ) and by rods that connect these conductive end caps to one another in the final assembly (shown and discussed below). The structure of FIG. 4 is illustrated in exploded views in FIGS. 5 and 6 . Specifically, in FIG. 5 certain of the separators 80 are exploded away from the rotor core and windings, and the shaft 62 is removed to show the sub-assembly of the core, damper cage and windings. FIG. 6 shows the conductive end cap laminations 84 and 86 removed. As may be seen in FIG. 6 , these end caps, made of a non-ferrous, conductive thin plate material forming a lamination, each comprises a central aperture for the shaft and peripheral apertures 88 that accommodate rods that will form, with the end cap laminations, the desired damper cage that aids in removing or reducing slot harmonics.
[0033] FIGS. 7 , 8 and 9 illustrate the skew formed in the rotor windings. In particular, as best shown in FIG. 7 , the shaft 90 has a center line which is displaced angularly from an orientation of the windings 78 by an angle 90 . This angle is caused by twisting of the rotor core prior to winding. In a presently contemplated embodiment, for example, a skew angle of approximately 10 degrees is employed. The skew is further shown in FIG. 8 , which is an end view of the rotor, as well as in FIG. 9 in which the shaft and windings have been removed. As may be seen in FIG. 9 , the apertures 88 of the end cap lamination 84 (and similarly of the opposite end cap lamination) are provided with a series of apertures 88 through which rods will be mounted in the core. Although not separately shown, similar apertures are provided in each of the core laminations forming the sides and a bridge section 92 . That is, each lamination generally has a rounded H shape with sides 74 and 76 extending around the central bridge section 92 , to form recesses for receiving the rotor windings. The skew is further illustrated in the sub-assembly view of FIG. 10 .
[0034] As shown in FIG. 11 , the damper cage 82 is formed by linking the front end cap lamination 84 with the rear end cap lamination 86 by means of a series of rods 94 extending between and receive in the apertures 88 . In the presently contemplated embodiment, 10 aluminum bars are positioned in these apertures, and extend through similar apertures in the laminations. The skew between the front end cap lamination and the rear end cap lamination is seen in FIG. 11 , as well as in FIG. 12 , which is an end-on view.
[0035] In a presently contemplated embodiment, the rotor is formed by first producing the sub-components, such as the laminations and front and rear end cap laminations. These may be punched or stamped from a thin plate-like material, and are in a present embodiment are made of steel with a nominal thickness of 0.028 in. The laminations are then stacked in a straight (not skewed) configuration, with a predefined number of laminations disposed between the front and rear end cap aluminum laminations. The aluminum bars are then inserted through the end cap laminations and the core laminations. The structure is then twisted to the desired angle, such as 10 degrees of skew. The end cap laminations are then secured to the ends of the rods, such as by staking, welding, or similar operations. The already-skewed core may then be pressed onto the rotor shaft, and the windings placed on the core to complete the sub-assembly along with the other rotor components as described above.
[0036] While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. | A rotor for a generator comprises a stack of laminate plates and conductive end caps on either side thereof. The laminate plates and the end caps have holes near a periphery thereof, and conductive rods are positioned in the holes, and secured to the end caps. The stack, the end caps and the rods are then skewed by a desired angle with respect to a centerline of the rotor. The resulting rotor core may then be mounted to a rotor shaft, and wound, with the windings also being skewed due to skewing of the core. The end caps and rods form a damper cage that aids in reducing harmonics. |
RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 09/119,165 filed on Jul. 20, 1998, (the parent application).
U.S. patent application entitled “Method for Generating Animation in an On-Line Book,” filed Jul. 20, 1998, application Ser. No. 09/119,331, and contains related subject matter.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to computers, and more particularly to a method for generating animation for an on-line book.
2. Description of Related Technology
Currently, there are several web publishing systems by which publishers of textual material can generate books which can be accessed on-line through a computer. One use of on-line books is to display literature on a company's products and services. Particularly in the computer industry, on-line books are often used to display and advertise goods, such as computers and computer peripherals as well as provide documentation for their use. Similar to traditional books, a reader of the on-line book can view each of the pages sequentially. However, a reader of the on-line books can also use a mouse or other input device to click on selected text to jump or hyper-link to another page in the book. The ability of on-line books to associate words or icons within a page to other words on other pages has caused many publishers to make available on-line versions of their materials.
An example of such a publishing system is the “WebBook Publisher” by Modem Age Books. This publishing system creates a plurality of data files which comprise the pages of an on-line book. Once created, the on-line book is typically transmitted by a compact disk to a user. The user then reads the electronic book with a viewing program. An example of a viewing program is the E-Doc 32 software program.
One prevalent viewing format is the Media View Version 1.4 (M14) file format. The M14 has become widely supported since a compiler for this format is part of the public domain. However, one problem with the existing publishing systems is that these systems do not allow for the automatic integration of an animated sequence upon the opening of a book. For example, the WebBook Publisher only provides a mechanism for inserting two visual images on the cover of the on-line book. The publisher of an on-line book typically uses the first image to display a title of the book and the second image to display the copyright notice. The WebBook Publisher does not provide for the ability to include an animated sequence upon the opening of an on-line book. The ability to include an animated sequence at the beginning of the on-line book would allow publishers to distinguish their books from the competition. Currently, manufacturers are unable to take full advantage of the functionality provided by a reader's computer, which would permit the production of an animated cover.
Therefore, on-line book publishers are in need of an application which provides for the generation of a animated object upon the opening of a book. This application should also allow for the automatic updating of any scripting and compiler files that are needed for the compilation of the on-line book.
SUMMARY OF THE INVENTION
One embodiment of the invention is an animation system for updating a plurality of compiler files, comprising at least two graphical images, a data sequencing module which arranges said at least two graphical images in an animated sequence, at least one compilation control file, and an update module which modifies said at least one compilation control file to include a reference to said at least two graphical images.
Another embodiment of the invention includes a system for inserting an animated display into an on-line book, comprising means for ordering a list of images which are displayed upon the opening of an on-line book, means for inserting the ordered list in a scripting file, means for inserting a reference to each of the images in a project file, means for inputting the project file into a compiler, and means for compiling the scripting file and the images into an on-line book.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating one embodiment of an animation system including an animator program.
FIG. 2 is a block diagram illustrating the components of the animator program shown in FIG. 1 .
FIG. 3 is a diagram showing the various computer architectures that may contain the animator program shown in FIG. 1 .
FIG. 4 is a flow diagram showing the animation process of the computer system shown in FIG. 1 .
FIGS. 5 a and 5 b are flow diagrams illustrating the animation process of the animator program shown in FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description is directed to certain specific embodiments of the invention. However, the invention can be embodied in a multitude of different ways as defined and covered by the claims. In this description, reference is made to the drawings wherein like parts are designated with like numerals throughout.
System Overview
Referring to FIG. 1, the functional components of an on-line book publishing system are illustrated. An image generator 50 is in communication with a compiler 52 . The image generator 50 is used to organize and create a plurality of individual pages which are used in an on-line book 56 . The image generator 50 may be any software publishing system that generates graphical data. An example of the-image generator 50 is the WebBook Publisher by Modem Age books. The compiler 52 may be any M14 on-line book compiler. An example of such compiler 52 is the Media View Compiler which is freely available to the public on the internet. The Media View Compiler can be downloaded from the internet location Custom Controls for Mediaview (visited Jan. 14, 1998)<http://www.innercity.com/mvreadme.htm>.
The compiler 52 may be invoked directly by the image generator 50 once a set of data files 60 are provided by the image generator 50 . The image generator 50 and the compiler 52 are in communication with a scripting file 54 and a master project file 58 . The master project file 58 , which typically as a filename extension of “.mvp,” is a text file that contains the name of each of the data files 60 to be included in the on-line book 56 . Typically, the image generator 50 provides a master project file 58 for each on-line book 56 . The master project file 58 contains a listing of compiler options, definitions, and a baggage section. The baggage section identifies for the compiler 52 the names of the files other than the text and program code that are to be included in the on-line book 56 .
The scripting file 54 includes a set of commands which are executed whenever a user first opens the on-line book 56 . Upon the creation of the on-line book 56 , the compiler 52 incorporates the scripting file 54 into the on-line book 56 . Typically, in the M14 file format the name of the scripting file 54 is “autoexec.scr.”
An animator program 62 is in communication with the scripting file 54 , the master project file 58 , and a group of animation files 64 . The animation files 64 comprise a plurality of bitmaps and graphical images which are designed to be displayed upon the opening of the on-line book 56 . In addition to having the graphical images of the animated sequence, the animation files 64 has a control file 65 .
The control file 65 contains the filenames of each of the graphical images which are a part of the animation process. In addition, the control file 65 contains a timing field for each file name, wherein the timing field indicates the length of time that each of the individual graphical images of the animation should be displayed before being replaced on the screen by the next graphical image. The control file 65 also has an indicator to arrange each of the graphical images in the order that the graphical images will be displayed. The data in the control file 65 may be alternatively stored in other formats. For example, the sequencing and timing data may be stored in system memory or the timing data and file names could be stored in a database. One of the purposes of the animator program 62 is to update the master project file 58 and the scripting file 54 to include references to each of the images in the animation graphics 64 . The animation program 62 also maintains a registry 66 which keeps historical information of user preferences such as the size of a user interface window. It is noted that in one embodiment of the invention, the animator program 62 is integrated into the image generator 50 .
Referring to FIG. 1, a viewing application 68 is used by a receiver of the on-line book 56 to view the pages of the on-line book 56 . Versions of the viewing software are commercially available to the public on the internet. The E-DOC32 can be downloaded from the internet location Welcome to Modern Age Books (visited Jun. 19, 1998) <http://www.mabooks.com>.
Now referring to FIG. 2, some of the components of the animator program 62 are illustrated. The animator program 62 is comprised of various modules 76 - 86 . As can be appreciated by one of ordinary skill in the art, each of the modules 76 - 86 comprises various sub-routines, procedures, definitional statements, and macros. Each of the modules 76 - 86 is typically compiled into a single executable program. Therefore, the following description of each of the modules 76 - 86 is used for convenience to describe the functionality of the animator program 62 . Thus, the processes that are undergone by each of the modules 76 - 86 may be arbitrarily redistributed to one of the other modules. The animator program 62 has a main module 76 which controls the other components of the animator program 62 . The main module 76 controls an update module 77 , a data sequencing module 81 , a copying module 82 , a user interface module 84 , and a registry module 86 . Each of these modules 76 through 86 are described further below.
The update module 77 includes an animation parser 78 and a project parser 80 . The animation parser 78 and the project parser 80 each control and update the scripting file 54 and the master project file 58 , respectively. The data sequencing module 81 maintains an internal list of the ordering of the animation files 64 (FIG. 1 ). The copying module 82 copies all of the animation files 64 into a directory which is known and accessible by the compiler 52 . The user interface module 84 provides a graphical interface to allow a user of the animator program 62 to select the animation sequence for the appropriate on-line book 56 . The registry module 86 controls and updates the registry 66 so as to record any user preferences that are observed.
The animation program 62 may be written in any programming language such as C, C++, BASIC, Pascal, and FORTRAN, and can run under any well-known operating system. C, C++, BASIC, Pascal, and FORTRAN are industry standard programming languages for which many commercial compilers can be used to create executable code.
FIG. 3 is a diagram illustrating a computer environment associated with the invention. A client computer 100 has a monitor 102 and a processing unit 103 . The processing unit 103 includes a memory for storing data therein. The client computer 100 includes the image generator 50 and the on-line book compiler 52 (FIG. 1 ). The client computer 100 is connected to a server computer 106 through a network 104 . The network 104 may include any type of group of computers that can communicate through a communication pathway including, for instance, the following networks: Internet, Intranet, Local Area Networks (LAN) or Wide Area Networks (WAN). In addition, the connectivity to the network may be, for example, remote modem, Ethernet (IEEE 802.3), Token Ring (IEEE 802.5), Fiber Distributed Datalink Interface (FDDI) or Asynchronous Transfer Mode (ATM). Note that computing devices may be desktop, server, portable, hand-held, set-top, or any other desired type of configuration.
The server 106 contains the animator program 62 . In one implementation, the server 106 includes a gateway which is connected to a WAN 108 . The WAN 108 has a plurality of network servers 110 . One of the network servers 110 is connected to a LAN 112 comprising a plurality of computers 114 . The animator program 62 may be located on one the network servers 110 or another computer in the network 104 . In one embodiment of the invention, the animator program 62 executes in part on a plurality of the network servers 110 . In another embodiment of the invention, the animator program 62 executes on a plurality of the computers 114 on the LAN 112 . In yet another embodiment of the invention, the animator program 62 resides on the client computer 100 . It is important to understand that the animator program 62 may be hosted on any computing device so long as a communication pathway exists between the animator program 62 , the animated graphics 64 , the scripting file 54 , and the master project file 58 .
Method of Operation
Referring to FIG. 4, the process for creating an on-line book 56 with an animated cover is illustrated. Starting at a state 100 , a user executes or runs the image generator 50 which the user uses to create a plurality of data files 60 . The data files 60 comprise the pages of the on-line book 56 . The method of creating the data files 60 using the generator is well known in the art. For further details, one may reference a user manual that traditionally comes with the image generator 50 .
Next, at a state 102 , the user runs the animator program 62 . The method of operation of the animator program 62 is described in further detail with reference to FIGS. 5 and 6. However, in summation, animator program 62 modifies the scripting file 54 generated by the image generator 62 , modifies the master project file 58 to include a reference to the animation graphics 64 , and copies the animation graphics 64 into a directory which is used by the compiler 52 to generate the on-line book 56 .
Moving to a state 106 , the compiler 52 compiles the data files 60 created by the image generator into an on-line book 56 . The process for compiling the data files using the scripting file 54 and the master project file 58 is known in the art. For further reference, one may review the on-line references provided by the Media View Compiler v1.4. Continuing to a state 108 , the user views the on-line book 56 through the use of the viewing application 68 .
Referring now to FIGS. 5 a and 5 b , the method of operation of the animator program 62 is further described. Starting at a state 200 , a user starts executing the animator program 62 . Moving to a decision state 202 , the animation program 62 may optionally customize the animator program 62 based upon personalized settings in the registry 66 . If the animator program 62 determines that there is information in the registry 66 , the animator program 62 configures the personalized settings at a state 204 . The personalized settings may define a size and location of the user interface window or a default project location of a master project file 58 . From the state 204 , or from state 202 if the animator program 62 determines there is no information in the registry 66 , the method moves to a decision state 206 .
At decision state 206 , the animator program 62 determines whether it has access to the master project file 58 , which may be located in the default project location. If the animator 62 finds the master project file 58 in the default project location, the animator program 62 proceeds to a state 214 . Otherwise, if the animator program 62 has a problem accessing the files in the default project location, the animator program 62 prompts the user at state 208 , asking whether the user wants to abort or retry to establish a connection with the default project location. Next, at a decision state 210 , if the user requests an abort, the animator program 62 calls a routine for application termination at a state 212 . At state 212 , during application termination the animator program 62 frees any memory that has been allocated. Otherwise, referring again to decision state 210 , if the user requests to retry the connection, the animator program 62 returns to the decision state 206 to re-test the connection with the default project location.
Referring again to the state 214 , the animator program 62 lets the user optionally change the project location from the default project to a new project location. Moving to a decision state 216 , the animator program 62 checks for the presence of the master project file 58 in the directory that was specified by the user. If the animator program 62 is not able to find a master project file 58 , the animator program 62 returns to state 214 to re-request another project location from the user. Once a valid project file is found, at a state 218 the animator program 62 displays a menu to the user through the user interface 84 . The menu describes various options to the user who is creating the animation. The menu provides a checkbox for the user to select one of the following options: to select another project location (state 214 ), to terminate the application (state 212 ), or to proceed with the animation process with the currently selected project location (decision state 222 ). Optionally, the menu may display an animated set of pictures during the animation process. The animated set of pictures is an identifier for the animating application.
If the user selects to proceed with the animation process, the method moves to the decision state 222 , wherein animator program 62 determines whether there is a connection to the animation files 64 . For the embodiment of the invention demonstrated with reference to FIGS. 4 and 5, the animation files 64 are created prior to the execution of the animator program 62 . However, the animator program 62 can optionally include an image generator 50 which will generate the graphical images in the animation files 64 during the animation process. Further, the animator program 62 will arrange and sequence each of the generated graphical images. The animator program 62 will also allow a user to designate the display time for each of the graphical images. As is appreciated by one of ordinary skill in the art, the process for creating an image generator 50 is well known.
If, in state 222 , the animator program 62 cannot access the animation files 64 , the process moves to a state 224 wherein the animator program 62 asks the user whether he or she wants to abort or to retry the connection with the animation graphics 64 . Sometimes the connection between the client 100 and the server 106 fails due to a network failure. However, these connection failures are sometimes transient. Next, at a decision state 226 , if the user requests an abort, the animator program 62 calls a routine for application termination at the state 212 . Otherwise, if the user requests to retry the connection, the animator program 62 returns to the state 222 to re-test the connection.
After the connection to the animation files 64 is established, the animator program 62 proceeds to a state 228 wherein it parses the animation files 64 into memory. Using the control file 65 , the animator program 62 parses into memory the file name of each of the graphical images. Proceeding to a state 230 , the animator program 62 reads into memory the project information from the master project file 58 and the scripting file 54 .
Moving to a state 232 , the animator program 62 inserts the filenames of the graphical images that were read from the control file 65 into the master project file 58 . Appendix “A” discloses an example of the state of a master project file 58 before and after the animation information has been added to the master project file 58 by the animator program 62 . Referring to Appendix “A,” a baggage section is included in the master project file 58 . The “Before” column of Appendix “A” contains the contents of a typical master project file 58 before the animation process is initiated. The majority of the filenames listed in the baggage section are the names of the files that are to displayed as pages in the on-line book 56 . An example of page files include the “backgnd.bmp” file the “cover.bmp” file and the “cpyr.bmp” file, which each respectively contain background material, a cover page, and a copyright notice.
The “After” column of Appendix “A” displays the state of the master project file 58 after being processed by the animator program 62 . As is seen in the “After” column, the animator program 62 has inserted the names of the graphical images that are used for the cover animation. Referring again to the “After” column of Appendix “A,” all of the files in the master project file 58 with the prefix “Animg” are used as part of the animation process. Each of the “Animg” files are a frame in the animation display.
Proceeding to a state 234 , the animator program 62 also updates the scripting file 54 . In the M14 file format, the scripting file 54 is eventually incorporated into the on-line book 56 by the compiler 52 . The scripting file 54 is executed when a viewer runs a viewer application 68 to open the on-line book 56 . The scripting file 54 sets up the user interface for the viewing application 68 .
Referring to Appendix “B,” the state of the scripting file 54 before and after the animation processing is illustrated. The “After” column of Appendix “B” shows that a series of Splash( ) commands are inserted into the scripting file 54 by the animator program 62 . The Splash( ) command displays a graphical image for an identified time frame. The format of the Splash( ) command is Splash(ImageFileName, Seconds, Removal). The variable ImageFileName is the filename of the image which is to be displayed. The variable Seconds defines the number of whole seconds the image is displayed before moving to the next line in the script. If a zero is used in the Seconds field, the image is displayed for a fraction of a second. The variable Removal defines the method to be used for removing the bitmap after the bitmap is displayed for the time specified in the Seconds field. A value of zero in the Removal field indicates that the displayed image should remain on the screen while the next command in the script is executed. A value of one in the Removal field indicates that the graphical image should be erased after it is displayed. If the size of the one graphical image is different than the next, the previous graphical image should.be erased to allow the next graphical image to be centered on the screen and drawn correctly. Also note that the designer of the this particular animation sequence chose to display each of the graphical images twice, instead of once, to fine-tune the animation effect.
In one embodiment of the invention, the values for the variables Seconds and Removal are supplied by the inventor. In another embodiment of the invention, the values for the variables Seconds and Removal are calculated by the animator program 62 so as to maximize the animation effect.
Next, at a state 236 , the animator program 62 saves a back-up version of the scripting file 54 and the master project file 58 . The back-up feature enables users of the animator program 62 to revert to pre-updated versions of the file if the user of the system decides not to use the animation display. Next, at a state 238 the animator program 62 starts a computing loop to copy all of the graphical images which are a part of the animation graphics 64 to a baggage directory. After the animator program 62 finishes operation, the compiler 52 looks into the baggage directory to find all of the files that are to be incorporated into the on-line book 56 . Proceeding to a decision state 240 , the animator program 62 checks whether the first image identified in the control file 65 is in the project baggage directory. If first image is not in the directory, at a state 242 the animator program 62 copies the image to the project baggage directory. Proceeding to a state 244 , the animator program 62 checks the next image in the control file 65 . Moving to the decision state 246 , if the animator program 62 determines that all of the graphical images are copied, the animation program 62 returns to state 218 to await further instructions from the user. Otherwise, if the animator program 62 determines that further images in the control file 65 need to be copied, the animator program 62 returns to the decision state 240 to finish the copying process.
The animator program 62 overcomes the problem of static title pages in an on-line book by providing a quick and efficient mechanism by which publishers of the on-line book 56 can incorporate an animated sequence onto the cover of an on-line book 56 . Before the teaching of the invention, on-line book publishers had no means for automatically updating the scripting file 54 and the master project file 58 . However, using the animator program 62 , a publisher may now update the scripting file 54 and the master project file 58 automatically upon receiving as input the file names of each of the images for the animated sequence. The animator program 62 may also optionally be used to create and arrange the graphical images of the animated sequence in their display order.
By using the animator program 62 , an on-line book publisher is able to create a professional product and make further use of the viewer's computer hardware. The animator program 62 also provides for the rapid insertion of the same graphical sequence in a plurality of on-line books. This feature is often needed when the graphical images comprise a standard trademark or logo of the on-line book publisher. However, by using the animator program 62 , the process for providing the animated image for a plurality of on-line books is easily accomplished.
While the above detailed description has shown, described, and pointed out fundamental novel features of the invention as applied to various embodiments, it will be understood that various omissions and substitutions and changes in the form and details of the system illustrated may be made by those skilled in the art, without departing from the intent of the invention. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
APPENDIX “A”
Before
After
[OPTIONS]
[OPTIONS]
COMPRESS=HIGH
COMPRESS=HIGH
ROOT=C:\Work\Compiled, rtf, baggage, zipped, images
ROOT=C:\Work\Compiled, rtf, baggage, zipped, images
WARNING=3
WARNING=3
SYSTEM=PC
SYSTEM=PC
MAKE=FULL
MAKE=FULL
BATCH=FALSE
BATCH=FALSE
TITLE=(new project)
TITLE=(new project)
CONTENTS=CONTENTS
CONTENTS=CONTENTS
[FILES]
[FILES]
contents.rtf
contents.rtf
Revisi˜1.rtf
Revisi˜1.rtf
1Intro˜1.rtf
1Intro˜1.rtf
2Insta˜1.rtf
2Insta˜1.rtf
3Adapt˜1.rtf
3Adapt˜1.rtf
4Troub˜1.rtf
4Troub˜1.rtf
5Quest˜1.rtf
5Quest˜1.rtf
ASmall˜1.rtf
ASmall˜1.rtf
BBusLo˜1.rtf
BBusLo˜1.rtf
Standa˜1.rtf
Standa˜1.rtf
N01.rtf
N01.rtf
N02.rtf
N02.rtf
N03.rtf
N03.rtf
N04.rtf
N04.rtf
[BAGGAGE]
[BAGGAGE]
init
Animg23.bmp
autoexec.scr
Animg10.bmp
backgnd.bmp
Animg11.bmp
cover.bmp
Animg12.bmp
cpyrt.bmp
Animg13.bmp
paltable
Animg14.bmp
credits.bmp
Animg15.bmp
1-1.bmp
Animg16.bmp
bullet.bmp
Animg17.bmp
note.bmp
Animg18.bmp
2-1.bmp
Animg19.bmp
2-2.bmp
Animg2.bmp
2-3.bmp
Animg20.bmp
2-4.bmp
Animg21.bmp
2-5.bmp
Animg22.bmp
2-6.bmp
Animg1.bmp
2-7.bmp
Animg24.bmp
2-8.bmp
Animg25.bmp
3-1.bmp
Animg26.bmp
3-2.bmp
Animg27.bmp
3-3.bmp
Animg28.bmp
3-4.bmp
Animg29.bmp
3-5.bmp
Animg3.bmp
3-6.bmp
Animg30.bmp
3-7.bmp
Animg31.bmp
3-8.bmp
Animg32.bmp
3-9.bmp
Animg33.bmp
3-10.bmp
Animg34.bmp
3-11.bmp
Animg35.bmp
3-12.bmp
Animg4.bmp
3-13.bmp
Animg5.bmp
3-14.bmp
Animg6.bmp
3-15.bmp
Animg7.bmp
3-16.bmp
Animg8.bmp
3-17.bmp
Animg9.bmp
3-18.bmp
Anicvr1.bmp
3-19.bmp
Anicvr3.bmp
4-1.bmp
Anicvr2.bmp
words.txt
Anicvr.bmp
Animg39.bmp
[KEYINDEX]
Animg40.bmp
keyword=1, “Toc Level 1”
init
keyword=2, “Toc Level 2”
autoexec.scr
keyword=3, “Toc Level 3”
backgnd.bmp
keyword=5, “Hidden Index Headings (Chapters)”
cover.bmp
cpyrt.bmp
[FTINDEX]
paltable
dtype0=MVBRKR!FBreakWords
credits.bmp
dtype1=MVBRKR!FBreakNumber
1-1.bmp
dtype2=MVBRKR!FBreakDate
bullet.bmp
dtype3=MVBRKR!FBreakTime
note.bmp
dtype4=MVBRKR!FBreakEpoch
2-1.bmp
2-2.bmp
[DLLMAPS]
2-3.bmp
MVBRKR=MVBK14W.DLL, MVBK14WD.DLL,
2-4.bmp
MVBK14N.DLL, MVBK14ND.DLL
2-5.bmp
MVMCI=MVMC14W.DLL, MVMC14WD.DLL,
2-6.bmp
MVMCI4N.DLL, MVMC14ND.DLL
2-7.bmp
MVIMG=MVMG14W.DLL, MVMG14WD.DLL,
2-8.bmp
MVMG14N.DLL, MVMG14ND.DLL
3-1.bmp
VERMONT1=VT216.DLL, VT216.DLL, VT232.DLL,
3-2.bmp
VT232.DLL
3-3.bmp
VRX1=VRX116.DLL, VRX116.DLL, VRX132.DLL,
3-4.bmp
VRX132.DLL
3-5.bmp
VRX2=VRX216.DLL, VRX216DLL, VRX232.DLL,
3-6.bmp
VRX232.DLL
3-7.bmp
3-8.bmp
[GROUPS]
3-9.bmp
group=Group1
3-10.bmp
3-11.bmp
3-12.bmp
3-13.bmp
3-14.bmp
3-15.bmp
3-16.bmp
3-17.bmp
3-18.bmp
3-19.bmp
4-1.bmp
words.txt
[KEYINDEX]
keyword=1, “Toc Level 1”
keyword=2, “Toc Level 2”
keyword=3, “Toc Level 3”
keyword=5, “Hidden Index Headings (Chapters)”
[FTINDEX]
dtype0=MVBRKR!FBreakWords
dtype1=MVBRKR!FBreakNumber
dtype2=MVBRKR!FBreakDate
dtype3=MVBRKR!FBreakTime
dtype4=MVBRKR!FBreakEpoch
[DLLMAPS]
MVBRKR=MVBK14W.DLL, MVBK14WD.DLL,
MVBK14N.DLL, MVBK14ND.DLL
MVMCI=MVMC14W.DLL, MVMC14WD.DLL,
MVMC14N.DLL, MVMC14ND.DLL
MVIMG=MVMG14W.DLL, MVMG14WD.DLL,
MVMG14N.DLL, MVMG14ND.DLL
VERMONT1=VT216.DLL, VT216.DLL, VT232.DLL,
VT232.DLL
VRX1=VRX116.DLL, VRX116.DLL, VRX132.DLL,
VRX132.DLL
VRX2=VRX216.DLL, VRX216.DLL VRX232.DLL,
VRX232.DLL
[GROUPS]
group=Group1
APPENDIX “B”
Before
After
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AttachUI(“”);
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SetBackgroundBitmap(“backgnd.bmp”,1);
StdButtons( );
StdMenus( );
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InsertButton(‘ma_button’, ‘Net Support’,
‘JumpURL(‘http://www.mei.micron.com’)’,-1);
InsertButton(‘ma_button’, ‘Net Support’,
Splash(“cover.bmp”,3,0);
‘JumpURL(‘http://www.mei.micron.com’)’,-1);
Splash(“cpyrt.bmp”,3,1);
Splash(“Animg1.bmp”,0,0);
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Splash(“Animg1.bmp”,0,0);
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‘JumpID(‘flashpt.mvb>main’, ‘CHAPTER1’)’, 0);
Splash(“Animg2.bmp”,0,0);
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Splash(“Animg3.bmp”,0,0);
‘JumpID(‘flashpt.mvb>main’, ‘CHAPTER2’)’, 1);
Splash(“Animg3.bmp”,0,0);
InsertMenu(‘mnu_goto’, ‘pos_2’, ‘3: Adapter and Device
Splash(“Animg4.bmp”,0,0);
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2);
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‘JumpID(‘flashpt.mvb>main’, ‘CHAPTER4’)’, 3);
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‘JumpID(‘flashpt.mvb>main’, ‘CHAPTER5’)’, 4);
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InsertMenu(‘mnu_goto’, ‘pos_5’, ‘A: Small Computer System
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Splash(“Animg20.bmp”,0,0);
Splash(“Animg21.bmp”,0,0);
Splash(“Animg21.bmp”,0,0);
Splash(“Animg22.bmp”,0,0);
Splash(“Animg22.bmp”,0,0);
Splash(“Animg23.bmp”,0,0);
Splash(“Animg23.bmp”,0,0);
Splash(“Animg24.bmp”,0,0);
Splash(“Animg24.bmp”,0,0);
Splash(“Animg25.bmp”,0,0);
Splash(“Animg25.bmp”,0,0);
Splash(“Animg26.bmp”,0,0);
Splash(“Animg26.bmp”,0,0);
Splash(“Animg27.bmp”,0,0);
Splash(“Animg27.bmp”,0,0);
Splash(“Animg28.bmp”,0,0);
Splash(“Animg28.bmp”,0,0);
Splash(“Animg29.bmp”,0,0);
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Splash(“Animg39.bmp”,0,0);
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Splash(“Animg1.bmp”,1,1);
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‘JumpID(‘flashpt.mvb>main’, ‘CHAPTER2’)’, 1);
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Configuration’, ‘JumpID(‘flashpt.mvb>main’, ‘CHAPTER3’)’,
2);
InsertMenu(‘mnu_goto’, ‘pos_3’, ‘4: Troubleshooting’,
‘JumpID(‘flashpt.mvb>main’, ‘CHAPTER4’)’, 3);
InsertMenu(‘mnu_goto’, ‘pos_4’, ‘5: Questions and Answers’,
‘JumpID(‘flashpt.mvb>main’, ‘CHAPTER5’)’, 4);
InsertMenu(‘mnu_goto’, ‘pos_5’, ‘A: Small Computer System
Interface’, ‘JumpID(‘flashpt.mvb>main’, ‘APPA’)’, 5);
InsertMenu(‘mnu_goto’, ‘pos_6’, ‘B: BusLogic Customer
Service’, ‘JumpID(‘flashpt.mvb>main’, ‘APPB’)’, 6); | A system for creating an on-line book with an animated cover. The system includes an animation program for inserting an animation sequence at the beginning of an on-line book which is compiled into the M14 format. The animation program includes: a user interface module configured to receive input from a user; a data sequencing module which arranges at least two graphical images in a sequence; and an update module which modifies at least one compilation control file. The animation program modifies the control files for an on-line book compiler to provide for the display of an animated object upon the opening of the on-line book. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for supplying electric current to a plurality of modules clustered in an electronic rack.
2. Discussion of the Background
It applies in particular, but not exclusively, to the electronic equipment carried on board aerodynes which are supplied from a DC electric current distribution network. It turns out that the DC voltage provided by this network is greatly perturbed, this being prejudicial in respect of the electronic equipment which might be supplied via such a voltage.
These perturbations originate firstly from the fact that the energy sources which supply this network are not unique. Indeed, when the engines of the aerodyne are stopped, the network is supplied from batteries, but when the engines are running, the network is supplied from electrical generators coupled to the engines. Moreover, an aerodyne in flight may be subject to strong electromagnetic perturbations, and in particular lightning, and this may give rise to considerable overvoltages in the electrical network or conversely brownouts.
Likewise, the variations in the load on this network and in the consumption by the equipment supplied therefrom, as well as the regulating transients of the generators, give rise to considerable momentary variations in voltage. Thus, for a nominal voltage of 28 volts, voltage variations possibly reaching 12 to 48 volts have been noted. Moreover, the overvoltages engendered by lightning may be much more considerable.
It is therefore necessary to provide a voltage regulating device in regard to each item of equipment carried, capable of withstanding and dealing with such voltage variations.
Moreover, equipment carried on board aerodynes is evolving towards an evermore modular and evermore integrated architecture comprising racks or cabinets in which are clustered a multiplicity of modules having needs in terms of supply voltage which vary from one module to another.
Each module has therefore been furnished with a supply device comprising all the necessary DC voltage conversion and regulating means. Now, the components allowing the regulating of such voltage variations are relatively voluminous and costly. It follows that, applied to a multiplicity of modules, this approach is costly and leads to the size of each module being considerably increased, and to its reliability being reduced since the module must then withstand large voltage variations.
SUMMARY OF THE INVENTION
The purpose of the present invention is to overcome these drawbacks. To this end, it proposes a supply device for supplying DC electric current to a plurality of consumer electronic modules, on the basis of a DC voltage exhibiting a wide voltage variation range, this device comprising voltage regulating means and voltage conversion means.
According to the invention, this device is characterized in that it comprises a primary supply module comprising voltage preregulating means able to step up or step down the voltage in order to provide the modules with a preregulated voltage exhibiting a small voltage variation range and, in regard to each module, voltage conversion means providing voltages adapted to the needs of the module.
By virtue of these arrangements, the costly and bulky power regulating components are clustered in a single module, while the converters integrated into each consumer module are inexpensive and compact, given that they are required to deal only with a voltage subject to small variations.
Thus, for example, when the voltage to be regulated varies between 12 and 48 volts around a nominal voltage of 28 volts, the primary supply module according to the invention makes it possible to obtain, as output, a preregulated voltage which varies at most between 18 and 32 volts. Such a range of variation is perfectly acceptable to cheap DC voltage converters available on the market.
Moreover, the wiring necessary to supply each consumer module from the supply module comprises just two electrical leads, each module remaining autonomous as regards the production of the voltages which it needs. Thus, this avoids the requirement to provide specific wiring to convey each necessary voltage between a common supply module and the consumer modules.
This solution therefore makes it possible to simplify the wiring, and thus to reduce the costs considerably.
Advantageously, the means of voltage conversion in regard to each module comprise galvanic isolation means making it possible to circumvent the perturbations which could occur on the preregulated current distribution line between the primary supply module and the consumer modules.
According to one particular feature of the invention, each consumer module is supplied by means of one respective line per primary supply module which comprises, at each supply line feed, automatic outage means for protection against short-circuits.
This arrangement makes it possible to obtain great security of operation, each module being supplied via an independent line and being able to be powered-up selectively by the primary supply module should there be a short-circuit in regard to the module of the supply line.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the device according to the invention will be described below, by way of non-limiting example, with reference to the appended drawings in which:
FIG. 1 diagrammatically represents an item of electronic equipment carried on board an aerodyne, clustering together several consumer modules and a primary supply module according to the invention;
FIG. 2 shows the primary supply module according to the invention;
FIG. 3 shows a secondary supply module according to the invention, with which each consumer module is equipped.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The electronic equipment 1 represented in FIG. 1 takes the form of a rack or a shelf into which are inserted and interconnected, by means of so-called “backplane” links 8 , a plurality of modules 2 to 5 , including a primary supply module 5 according to the invention, which groups together the functions of preregulating the primary voltages to 28 volts provided by the general supply to the aerodyne.
Generally, an aerodyne comprises at least two DC electric current distribution networks, namely a main network and a backup network. The primary supply module is then connected to these two networks as shown by the figure.
More precisely, the primary supply module 5 caters for the functions of overvoltage limitation, of clipping of transient voltages due to lightning and of compensation for fleeting voltage drops, for the purpose of delivering a voltage preregulated to 28 volts to the other modules 2 to 4 . Indeed, it turns out that the voltages provided by the general supplies of an aerodyne are subject to large variations, from 12 to 48 volts, these variations possibly being much greater when transient.
The primary supply module 5 groups together on a single electronic card a set of relatively bulky and costly components so as to provide several modules with a preregulated voltage exhibiting a small range of variations, for example from 18 to 32 volts, which may then be adapted by cheap voltage converters 6 integrated into each module and capable of providing the varied voltages used by them.
In FIG. 2, the primary supply module 5 comprises successively in series, for each of the aerodyne's 28-volt supply lines applied as input:
a clipping device 11 , 12 , consisting of a Zener diode and/or a similar device such as a varistor, connected in parallel between the respective supply line and earth, this device making it possible to eliminate pulses greater than 80 volts, due for example to lightning,
a low-pass filter circuit 13 , 14 linked to the output of the clipping device 11 , 12 ,
automatic switching means 27 , 28 for supplying or not supplying the remainder of the circuit depending on the presence or absence of voltage applied as input, these means being configured in such a way as to give preference to one of the two supply networks 9 , 10 of the aerodyne, when both the latter are available, and
a voltage preregulating circuit 15 , 16 for clipping the voltage and for limiting the current output by the filter circuit 13 , 14 .
The primary supply module 5 furthermore comprises a voltage step-up/regulator circuit 17 connected to the two voltage preregulating circuits 15 , 16 so as to apply a voltage of 28 volts to the remainder of the circuit for a few tens of seconds, for example 30 seconds, when the input voltage has fallen to 12 volts minimum, and a current distribution circuit 18 connected to the output of the voltage step-up circuit 17 . The distribution circuit 18 comprises an energy reserve 20 consisting for example of a bank of capacitors, and a set of electronic cutouts 21 to 23 which respectively provide the other modules 2 to 4 of the rack 1 with a preregulated 28-volt DC voltage.
It should be noted that the energy reserve 20 is located at the output of the voltage step-up/regulator circuit 17 which therefore applies a stepped-up and almost constant voltage thereto. Since the charge of a capacitor is proportional to the voltage applied across its terminals, the energy stored in the energy reserve 20 therefore remains almost constant and high irrespective of the level of the voltage provided by the network.
By virtue of these arrangements, the primary supply module 5 is capable of compensating for cutouts of a few tens of milliseconds (20 to 200 ms for example) by maintaining the supplies to the modules 2 to 4 .
The cutouts 21 to 23 are designed in such a way as to open automatically in case of a downstream short-circuit, and to reclose automatically when they are subjected to voltage. They thus ensure separate protection of the primary supply module 5 against the short-circuits which may occur in regard to the modules 2 to 4 or in the connections between the modules and the cutouts, and hence guarantee the availability of the supply and the non-propagation of failures, in case of a short-circuit in a module.
The preregulating circuits 15 , 16 each comprise a blocking diode preventing the capacitors 20 from discharging to the networks 9 , 10 , in the case of circuit outage.
Moreover, the module 5 furthermore comprises two network outage detection devices 25 , 26 respectively connected in parallel between the output of the filters 13 , 14 and the output of the voltage step-up circuit 17 . When the duration of outage of the networks exceeds the time of cover by the energy reserve 20 , the network outage detection devices 25 , 26 indicate to the modules 2 to 4 , with the aid of the signals 25 a and 26 a , that there will be a total loss of supply within a short interval of a few milliseconds (2 to 20 ms). The appearance of the signals 25 a and 26 a triggers a process whereby certain critical flight parameters computed in particular by the modules 2 to 4 are stored in memory with battery or capacitor backup. The memory write time is of the order of 2 to 20 ms, whilst the necessary storage time for these parameters is in general between 200 ms and 5 s.
Certain electronic cutouts 21 to 23 may also be opened with the aid of a signal 19 emanating from the main network 9 detector 25 upon the loss of this network and when it is not desired to supply one or more modules 2 to 4 with the backup network, so as to avoid too considerable a load thereon.
The module 5 also comprises a non-volatile maintenance memory 24 , of FPROM type for example, making it possible to store all the events liable to facilitate the maintenance of the module, such as for example the opening of a cutout 21 to 23 and the network cutouts which have given rise to changes of state of the switches 27 , 28 . The contents of this memory 24 are updated by the consumer modules 2 to 4 which have write and read access thereto so as to verify each write. This memory can also be updated by the outage detectors 25 , 26 , and by the cutouts 21 to 23 and the switching devices 27 , 28 , which have, to this end, a binary output giving the state of the cutout or of the switching device, respectively.
This primary supply module 5 provides the other modules 2 , 4 of the item of equipment 1 with a preregulated voltage which can then be adapted by the other modules by means of integrated secondary supply blocks 6 having a much simpler and less bulky structure which is consequently less costly than if the voltages provided by each network of the aerodyne had had to be adapted to the needs of each module.
Thus, in FIG. 3, each secondary supply block 6 comprises an input filter 31 receiving the preregulated voltage of 28 volts, making it possible to eliminate the high frequencies which may appear in regard to the connection lines between the cutouts 21 to 23 and the supply blocks 6 . The output of the input filter 31 is connected to a DC voltage converter 32 comprising a primary block and a secondary block which are isolated galvanically by a pulse transformer. The supply to the modules is thus isolated galvanically from the primary supply module 5 . The converter 32 is for example of the 0-volts-switched “flyback” chopper type. The secondary block makes it possible to provide the various voltages V 1 , V 2 , V 3 , necessary for the module, for example 5 V and +/−15 V, which are pre-filtered by output filters 33 , 34 making it possible to eliminate any high frequencies which might be introduced by the chopper-type converter 32 .
Moreover, the converter 32 is voltage-slaved by a control circuit comprising a primary circuit 35 receiving control signals, and a secondary circuit 36 , which are isolated from one another, providing monitoring signals, these two circuits 35 , 36 being galvanically isolated by a pulse transformer 37 . The secondary control circuit 36 measures one of the voltages at the output of the filters 33 , 34 , for example the voltage V 1 , so as to generate a control signal which is transmitted to the primary circuit 35 . The primary circuit 35 converts this signal on the basis of a maximum preset output power, into a second control signal which is applied to the switching transistors of the chopped converter 32 . Regulation of the other output voltages V 2 , V 3 , is obtained by virtue of the magnetic coupling produced by the transformer of the converter 32 and by virtue of the symmetry of the latter's circuits. Such a converter does not require any minimum load on its outputs. | A power supply for a plurality of electronic modules in a compartment. DC electric current is provided to a plurality of consumer electronic modules on the basis of a perturbed DC voltage exhibiting a wide voltage variation range. The supply device includes a primary supply module and a voltage preregulator able to step up or step down the DC voltage in order to provide the modules with a preregulated voltage exhibiting a small voltage variation range. Each module includes a voltage conversion device for providing the voltages adapted to the needs of the module. |
This is a continuation of copending application Ser. No. 296,639, filed on Jan. 13, 1989.
BACKGROUND OF THE INVENTION
The field of the invention relates to films for packaging foodstuffs and other articles.
Certain films, though having excellent properties such as transparency, stiffness, and moisture barrier, have unacceptably high coefficients of friction which makes them difficult to utilize in automatic packaging equipment. Highly crystalline polypropylene film is one such film having the above-mentioned properties.
A number of approaches have been taken to improve the surface friction characteristics of films, including polypropylene films. One such approach is described in U.S. Pat. No. 3,176,021, and involves the inclusion of minor quantities of fatty acid amides into the polypropylene. U.S. Pat. No. 4,419,411, which is incorporated by reference herein, discloses a film having a base layer comprising polypropylene of high stereoregularity, the precursor resin of which contains an amide of a water-insoluble monocarboxylic acid, and a poly-olefin skin layer containing finely divided silica and a silicone oil. Some of the amide within the base layer blooms to the skin layer, thereby reducing the coefficient of friction to 0.25 or less at a temperature up to about 140° F.
The use of various silicone oils has been found to provide satisfactory reductions in the coefficients of friction of a variety of films, thereby facilitating their use in automatic packaging machines. U.S. Pat. Nos. 4,652,489, 4,659,612, 4,692,379, 4,720,420, 4,734,317 and 4,764,425, which are incorporated by reference herein, all disclose sealable films which employ polydialkylsiloxane as a slip agent. U.S. Pat. Nos. 4,659,612, 4,692,379 and 4,734,317 provide methods for reducing the coefficient of friction of both sides of a film laminate by adding a silicone oil such as polydimethylsiloxane to one surface layer thereof, and then contacting this surface layer to the second surface layer of the film to transfer some of the oil thereto. The second layer may be corona or flame treated to enhance its receptivity to water-based coatings such as certain inks and adhesives prior to the application of the silicone oil.
Films having a layer incorporating polydialkylsiloxane are relatively difficult to treat using conventional methods, and the bond strengths of such films when laminated may also be unacceptably low. Corona or flame treating a film surface layer containing such a silicone oil reduces the heat sealability thereof and increases the coefficient of friction. The benefits of the silicone oil are accordingly lost. Metallized coatings applied to such a surface layer may not tend to adhere as well to such surface layers as compared to surfaces devoid of silicone oil.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a film having excellent bond strength and surface friction characteristics.
It is another object of the invention to provide a method for manufacturing such a film in an efficient manner using conventional equipment.
A still further object of the invention is to provide a method which allows great flexibility in combining film layers having selected properties, is sealable on both the inner and outer skin layers, has excellent bond strength, and has excellent slip characteristics on both surfaces.
In accordance with these and other objects of the invention, a laminated film is provided including first and second webs, the first web including a core layer and a surface layer, the surface layer of the first web containing an effective amount of polydialkylsiloxane to reduce the coefficient of friction thereof, and an adhesive layer bonding the first and second webs to each other. The surface or skin layers of each web are sealable, and preferably heat sealable. Polydialkylsiloxane is transferred from the skin layer of the first web to the skin layer of the second web in order to reduce the coefficient of friction thereof.
The method according to the invention includes the steps of providing a first web including a core layer and a skin layer, the skin layer containing a silicone oil such as polydialkylsiloxane, providing a second web, applying an adhesive between said first and second webs to bond them together, and contacting the skin layer of the first web to the exposed surface of the second web, thereby transferring silicone oil thereto.
The surface of the first web which is adhered to the second web may be treated so that it is receptive to ink. The bonding of the second web to the first web thereby locks in any printing on this surface so that it cannot be damaged in a packaging operation.
DETAILED DESCRIPTION OF THE INVENTION
A laminated film is provided which includes an outside web, an inside web, an adhesive layer bonding the webs to each other, one of the webs including a surface layer containing a silicone oil, the other of the webs including a surface layer substantially devoid of silicone oil except for oil which is transferred by contact of the surface layer of the one web therewith. The outer surfaces of the laminated film are preferably heat sealable. Such a laminated film can be used for packaging foodstuffs and the like in either belt-driven or non-belt-driven packaging machines and regardless of whether fin or lap seals are formed thereby.
When polyolefin films are formed into bags or sacks for receiving articles, the outer surfaces thereof can become scratched if the coefficient of friction is relatively high at the temperature at which such bags are constructed. The excessive drag which may cause such scratching may also cause the packaging apparatus to jam. Due to the advent of belt-driven packaging apparatus including an inside shaping tube which allows the belts to engage the film between the tube and belts, it is now important that both surfaces of the film have satisfactory hot slip performance. This allows the film to be processed on both the new belt-driven apparatus as well as older equipment.
Silicone oils of the types described in U.S. Pat. No. 4,659,612 have been found to impart satisfactory slip characteristics to oriented polypropylene films. In accordance with the present invention, the outside web of the laminated film includes a thin skin layer (a) (about 2-6 gauge units in thickness) containing an amount of silicone oil sufficient to maintain a low coefficient of friction thereon. The skin layer is a heat seal layer preferably formed from ethylene-propylene random copolymers and/or ethylene-propylene-butene-1 terpolymers.
The latter includes 2-9 wt. % and preferably from about 3-7 wt. % ethylene, and 2-9 wt. % and preferably about three to about seven percent by weight of 1-butene. Suitable polymers generally have a melt flow rate at 446° F. ranging from 1-15 and preferably 2-7. The crystalline melting point is between about 245°-302° F. The average molecular weight range is about 25,000-100,000 and the density is 0.89-0.90. The silicone oil, preferably polydimethylsiloxane, is added in amounts between about 0.3% to about 5.0% by weight of the heat sealable skin layer. The preferred range is between 1.1-1.5 wt. %.
The skin layer (a) is compounded with an effective amount of anti-blocking agent to help maintain a low coefficient of friction. A finely divided, particulate, inorganic material is preferred having a mean particle size ranging from about 0.5 to 5 microns. One commercially available silica has a mean particle size of 0.75 microns and another has a mean particle size of 4.5 microns. Materials having either particle size or particle sizes within this range can be employed. Metal silicates, glasses, clays and numerous other finely comminuted inorganic materials may also be used. The anti-blocking agent is preferably present in amounts from about 0.05 to 0.5 wt. %, preferably about 0.1 to 0.3 wt. % of each of the skin layers.
The core layer (b) of the outside web is preferably derived from isotactic polypropylene which may contain effective amounts of anti-static agents as described in U.S. Pat. No. 4,764,425. The polypropylene homopolymer has melting point range between 321°-325° F.
The polypropylene core layer provides a moisture barrier and stiffness to the outside web. Other possible core materials include oriented high density polyethylene, oriented polystyrene, oriented polyethylene terephthalate, polycarbonate and nylon.
A second skin layer (c) may be provided having a surface which is receptive to ink. This skin layer (c) may comprise the same copolymer and/or terpolymer blend as layer (a), but is subjected to corona, flame, plasma or chemical treatment to impart ink receptivity. This layer may alternatively be omitted and the inner surface of the core layer (b) instead subjected to such treatment.
A primer may be added to the second skin layer depending upon the ink which is to be used thereon. Any of a number of commercially available primers would be suitable for enhancing receptivity to ink and/or adhesive, including poly(ethyleneimine), acrylic styrene copolymers, urethane and epoxy. The application of several such primers is discussed in U.S. Pat. No. 4,565,739, which is incorporated by reference herein.
If a primer is employed, virtually any type of ink would be acceptable for application to the core (b) or skin layer (c), whichever is receptive to ink. Since only certain inks adhere to a silicone oil treated film in the absence of a primer, urethane, nitrocellulose, epoxy or polyamide blends should be employed if a primer is not applied. If a urethane adhesive is employed, a water-based ink such as that sold by Crown Zellerbach under the name AQUALAM P, or modified polyamide or nitrocellulose inks or blends thereof, would be satisfactory. If an extrusion (poly) or PVDC adhesive is employed, urethane-nitrocellulose and epoxy-nitrocellulose blends are preferred.
The inside web includes a core layer (b 1 ), a bonding surface layer (c 1 ) for bonding with the adhesive, and an inner, heat sealable inner skin (a 1 ). The skin (a 1 ), core (b 1 ) and bonding surface (c 1 ) layers, respectively, may be comprised of the same materials which are mentioned as suitable for the skin (a), core (b), and second skin (c) layers of the outside web. The skin (a 1 ) of the inside web is substantially devoid of silicone oil, however, which enhances the adhesion of a metallized coating which may be applied to the bonding surface layer (c 1 ). The latter is preferably between about two and seventeen gauge units in thickness. It may contain a slip agent (e.g. 700-3,000 ppm oleamide, stearamide, or erucamide or blends thereof).
While not required, each web is preferably manufactured by employing commercially available systems for coextruding resins. A polypropylene homopolymer of comparatively high stereoregularity is co-extruded with the resins which constitute one or both skin layers thereof. The polymerscan be brought into the molten state and co-extruded from a conventional extruder through a flat sheet die, the melt streams being combined in an adapter prior to being extruded from the die. After leaving the die orifice, the multi-layer film structure is chilled and the quenched sheet then preferably reheated and stretched, for example, three to six times in the machine direction and subsequently four to ten times in the transverse direction. The edges of the web can be trimmed and the film wound onto a core.
A metallized coating may be applied to the bonding surface layer (c 1 ) of the inside web using any acceptable method such as that described in U.S. Pat. No. 4,345,005, which is incorporated by reference herein. Other coatings may alternatively be employed depending on the properties desired for the film. A PVDC coating may, for example, be provided to improve the gas and moisture barrier properties of the web.
The inside and outside webs are bonded to each other through the use of commercially available adhesives and conventional bonding processes. The choice of adhesives depends on the properties which one wishes the laminated film to have. A urethane adhesive provides mainly only adhesion. Extruded polymer resins can provide thickness, stiffness and durability. As discussed above, PVDC provides a gas barrier and an additional moisture barrier. If a dry bonding technique is used, the adhesive is applied to one of the webs, the solvent is evaporated out of the adhesive, and the adhesive-coated web is combined with the other web by heat and pressure or pressure only.
Extrusion laminating involves the use of an extruder to melt and continuously apply a controlled amount of a very viscous melted resin, usually polyethylene, directly between the web materials being laminated. The bond is achieved as the melted resin resolidifies in situ. Primers or precoatings may be employed to augment the bond or improve resistance to chemical attack.
Once the outside web has been bonded to the inside web, the resulting laminated film is wound onto a core and maintained in this form for a period of about six hours to one week at a temperature of about 80° to about 125° F. The winding of the film causes the skin layer (a) of the outside web to contact the skin layer (a 1 ) of the inside web. The silicone oil, which is generally substantially uniformly distributed on the exposed surface of skin layer (a), is responsible for imparting a reduced coefficient of friction to this surface as well as to the exposed surface of the inner skin layer (a 1 ) when some of the oil is transferred thereto after these surfaces have been placed in mutual contact. A sufficient amount of silicone oil should be employed to provide a coefficient of friction of layers (a) and (a 1 ), following transfer of silicone oil microglobules to the latter, of about 0.4 or less, preferably 0.25-0.3, up to at least about 60° C.
The thickness of the outside web is primarily due to the thickness of the oriented polypropylene core. The surface layers (a) and (c) may comprise, for example, a total of about eight percent of the total thickness of an 80 gauge web. The total outside web thickness is ordinarily in the range of about 0.35-2.0 mils. The total thicknesses of the inside and outside webs are not critical to the present invention.
The following are specific examples of films which can be manufactured in accordance with this invention.
EXAMPLE 1
A laminated film comprising an outside web having a coextruded abc structure, an inside web having a coextruded a 1 b 1 c 1 structure, and an adhesive bonding the c layer of the outside web to the c 1 layer of the inside web is provided.
The "a" layer is an ethylene propylene random copolymer containing about six percent ethylene. This layer is about 2.2 gauge units (0.55 microns) in thickness, is 1.2 wt. percent polydimethylsiloxane, and includes about 2330 ppm SiO 2 . The "b" layer of the outside web is an isotaotic polypropylene containing about 0.1% N,N bis hydroxyethylamine and is about seventy-five gauge units in thickness. The "c" layer is about three gauge units in thickness, is made from the same copolymer as layer "a", is flame treated and coated with a polyethyleneamine primer.
The c 1 layer is made from an isotactic polypropylene homopolymer and contains about 2300 ppm SiO 2 . It is about three gauge units in thickness and is flame treated. The b 1 layer is about seventy-five gauge units in thickness and is made from isotactic polypropylene with no additives. Finally, the a 1 layer is fourteen gauge units in thickness (for hermetic sealability) and is formed from an ethylene-propylene random copolymer (about 6% ethylene) containing 2300 ppm SiO 2 and a slip agent (e.g. oleamide, stearamide, erucamide and blends thereof).
The urethane adhesive bonds the c layer of the outside web to the c 1 layer of the inside web. The laminated film is wound upon a roll whereupon some of the polydimethylsiloxane within the "a" layer is transferred to the a 1 layer.
EXAMPLES 2-3
The same film structure as Example 1 is provided except the a 1 layer is four and six gauge units, respectively, in thickness.
EXAMPLE 4
The same film structure as Example 1 is provided except the a and a 1 layers are both made from EPB-1 random terpolymers containing about 5% ethylene, 8% butene-1 and 87% polypropylene.
EXAMPLE 5
The same film structure as Example 1 is provided except the c 1 layer has a metallized (aluminum) coating deposited thereon.
EXAMPLE 6
The same film structure as Example 1 is provided except the "a" layer is formed from a random copolymer containing about 6% butene-1 and 94% polypropylene. | A polymer film laminate is provided having improved machinability on modern high speed belt drive machines, particularly when these machines are set up to form lap back seals. A method of assembling such a film is also provided. The film includes an outside web having an upper surface layer containing a silicon oil. This laminating web can be used with virtually any co-laminate, metallized or not, which is bonded thereto with an adhesive. Upon winding the composite film laminate upon a core, silicone oil is transferred to the inside surface of the laminate, thus providing an inside coefficient friction which is about equal to or less than the outside coefficient of friction. Hot slip properties are also improved upon such transfer. The outside and inside webs are independently formed, which allows the inside web to include coatings or film layers which are not ordinarily usable in a silicone oil-containing film. |
This application is a continuation of application Ser. No. 07/843,746, now abandoned, filed Feb. 28, 1992. This application is a division of application Ser. No. 07/733,922, now U.S. Pat. No. 5,110,748, filed Jul. 22, 1991, which is a division of Ser. No. 07/676,998, now abandoned filed Mar. 28, 1991 , now abandoned.
FIELD OF THE INVENTION
The invention pertains to active matrix displays, and particularly pertains to integrated drivers for active matrix displays. More particularly, the invention pertains to high mobility thin film transistors for fabricating integrated drivers for active matrix displays.
BACKGROUND OF THE INVENTION
Flat panel displays show a significant potential for reducing the weight, volume, power consumption, and cost, as well as providing enhanced reliability compared to the conventional cathode ray tube (CRT) displays. These displays are being developed as a replacement for CRT displays in several select applications such as for computer, entertainment, military and avionic displays. The display technologies, namely plasma, thin film electroluminescence (TFEL), and active matrix liquid crystal displays (AMLCD), which are being actively developed to realize this potential, share the common features of matrix addressing and the associated driver interconnect problems. Presently, the row and column drivers are fabricated using bulk single crystal silicon. The driver chips are interconnected to the display glass using either the flex cable, or chip-on-glass approach. Both approaches limit the achievable display resolution due to minimum interconnect pitch required, consume significant peripheral space, and present reliability issues due to the thousands of interconnects between the glass and driver chips.
By fabricating drivers on glass (integrated drivers), the above problems can be alleviated. Integrated drivers drastically reduce the number of interconnects from several thousand to around 10, allow higher resolution, redundancy, and greater flexibility in display system packaging, and improve display reliability. Unfortunately, the present amorphous silicon (a-Si) and polysilicon (poly-Si) thin film transistor (TFT) technologies do not allow fabrication of high resolution integrated drivers due to their low mobility. A-Si has mobility in the range of 0.1-1.0 centimeter 2 /volt*second (Cm 2 /V.S.), which is too low for fabricating integrated display drivers. Poly-Si has a mobility in the range of 10-50 Cm 2 /V. Sec. and has been used to fabricate integrated drivers for moderate resolution displays such as 480 H×440 V pixels. However, for higher resolutions such as 1024 H×1024 V, use of poly-Si TFTs requires a complex series/parallel driver architecture, without a dramatic reductions in the number of interconnects required.
High resolution active matrix displays require drivers capable of being operated in the several megahertz frequency range. Such performance requires a semiconductor with a field effect mobility in excess of 300 centimeter 2 /volt.second. Only single crystal silicon is known to satisfy this requirement. Single crystal silicon allows simpler driver architecture and dramatically reduces the number of interconnects needed. However, it has not been possible to deposit single crystal silicon films on display glass substrates. Depending on the substrate temperature, such depositing of silicon films results in films that are either amorphous or polycrystalline, and have lower mobility. Yet, single crystal silicon films can be deposited on sapphire substrates, i.e., silicon on sapphire (SOS) technology, which are transparent. Although SOS transistors have high mobility, their leakage currents are unacceptably high for active matrix display application. Other disadvantages are that large area sapphire substrates are not readily available and they are expensive.
Electrostatic bonding of a single crystal silicon wafer to a glass substrate and thinning (preferential etching) of the silicon wafer have been used by others for producing high mobility single crystal silicon films on glass substrates. Others have utilized CORNING Code 1729 glass substrates in their experiments. The 1729 substrate is a high temperature (i.e., strain point=850° Celsius (C.) glass. The glass has been produced by Corning Corp. in a small rod form and sliced into wafers in experimental quantities. This 1729 glass is difficult to produce with large areas for practical applications due to its high temperature. The most commonly available display glass substrates for practical applications are CORNING Code 7059, CORNING Code 1733, HOYA NA40, and ASAHI NA. The upper useable temperature limit of these display glass substrates is about 640° C. The difficulty is that such temperature is not adequate for forming a high quality thermal silicon dioxide gate dielectric utilized in the conventional MOS processing for display driver circuits or chips. Transistors fabricated with deposited silicon dioxide gate dielectric at temperatures less than 700° C., generally have higher threshold voltages and/or threshold voltage instabilities due to defects in such deposited dielectric. Additionally, these thin film transistors (TFT), when used as active matrix switches, require light shields at the top and bottom to maintain low leakage currents (i.e., off-currents), while operating under high ambient light conditions. However, in view of the conventional electrostatic bonding and preferential thinning approach, it is not possible to light shield the bottom side of the TFT because the back interface of the substrate is not accessible after electrostatic bonding. There is a great need for a process of fabricating high mobility TFTs and integrated drivers, which circumvents the above-mentioned problems. The present invention is a process which solves those problems.
SUMMARY OF THE INVENTION
The present invention is a method for fabricating high mobility TFTs and display drivers integrated on the active matrix substrate. Besides resulting in the single crystal silicon for high field effect mobility, there is a thermal silicon dioxide gate dielectric for a low and stable threshold voltage, and light shields for low off-currents under high ambient lighting conditions. Thus, a high resolution active matrix display with integrated display drivers operable in the multi-megahertz frequency range, is achievable with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a method flow diagram for fabricating high mobility TFTs and an active matrix substrate having integrated drivers.
FIG. 2 is a cross-sectional view of a display glass substrate and a single crystal silicon wafer prepared for bonding.
FIG. 3 is a cross-sectional view of the display glass substrate after the bonding and thinning of the single crystal silicon.
FIG. 4 is a cross-sectional view after the silicon islands, along with the gate dielectric, have been etched.
FIG. 5 is a plan-view of the silicon islands with the gate dielectric.
FIG. 6 is a cross-sectional view of the substrate having a spin-on-glass planarization layer.
FIG. 7 is a plan-view of the substrate with the spin-on-glass layer.
FIG. 8 shows a deposition pattern and etch for a polysilicon gate.
FIG. 9 reveals the source-drain implants.
FIG. 10 shows the inner metal dielectric deposition, pattern and etch of contact vias.
FIG. 11 indicates the source and drain metal deposition, pattern and etch.
FIG. 12 reveals a passivation layer deposition, light shield layer deposition, pattern and etch.
FIG. 13 reveals an alternate process sequence for the first part of the process for fabrication of high mobility TFTs.
FIG. 14 shows a preprocessed silicon handle wafer and silicon device wafer prior to bonding.
FIG. 15 shows a cross section of the silicon handle wafer, the thermal silicon dioxide dielectric and the silicon epitaxial device layer after the silicon device wafer and the p ++ etch-stop layer have been selectively etched away.
FIG. 16 shows the preprocessed silicon handle wafer prior to its electrostatic bonding to the display glass substrate.
FIG. 17 shows a cross section of the display glass substrate after electrostatic bonding and selective etching of the silicon handle wafer.
FIG. 18 is a cross-sectional view after the silicon islands along with the gate dielectric, have been etched.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows the process flow for fabrication of high mobility n-channel TFTs. The process steps are described in conjunction with the ensuing figures.
FIG. 2 reveals a silicon substrate 12 and display glass substrate 14 prior to electrostatic bonding. Single crystal silicon substrate 12 is P-type has a boron concentration greater than 8×10 18 atoms/Cm 3 , a (100) orientation, (P ++ ) and a thickness of approximately 0.5 millimeters. Silicon substrate 12 is initially thermally oxidized in dry oxygen to produce about 0.5 micron of high quality silicon dioxide on surface 16. The thermal silicon dioxide is then patterned and etched to produce gate dielectric regions 18 for the TFTs to be fabricated. The pattern on the oxide also includes alignment keys for registration of the subsequent layers to gate dielectric regions 18. Next, approximately 1.5 microns of lightly doped epitaxial (epi) silicon 20 is grown on top of silicon wafer 12 containing oxide islands 18. Because an SiO 2 layer presents a difficult nucleation surface for silicon chemical vapor deposition (CVD), lateral epitaxy results on top of oxide islands 18. Thus, a uniform epitaxial layer 20 of lightly boron doped, high mobility silicon of about a 1.5 micron thickness is produced by a selective epitaxial process. On top of layer 20, a Si 3 N 4 barrier layer 22 is deposited with a thickness of about 0.25 micron via plasma CVD. Barrier layer 22 serves as an isolation layer. Silicon dioxide deposited by plasma CVD may also be used as a barrier layer. On layer 22, a light shield layer 24 of about 0.2 micron is deposited. After deposition of layer 24, silicon wafer 12 is then ready for bonding. Light shield layer 24 may be composed of refractory metal or similar substance, which is compatible with the electrostatic bonding process and barrier layer 22. Silicon wafer 12 incorporating layers 20, 22 and 24, is then electrostatically bonded to display glass substrate 14 at light shield 24 surface of wafer 12. Provision for electrical contact to light shield layer 24 for electrostatic bonding may be made by any one of various means. For example, silicon wafer 12 can be made larger than glass substrate 14 to have access to light shield layer 14, for electrical contact during bonding. Display glass substrate 14 may be CORNING Code 1733 or other like material. Substrate 14 is approximately 1.1 millimeters thick. Electrostatic bonding involves applying approximately 1000 volts direct current across the display glass substrate 14 and wafer 12 for a bonding between layers 14 and 24 at a temperature of about 600° C.
After the bonding of layers 14 and 24, P ++ silicon substrate 12 is etched off starting from the surface opposite of surface 16, down past surface 16 on into layer 20, including some of islands la to a level wherein a portion of thickness of islands 18 is remaining. This etching is accomplished with the use of impurity selective etch 8HAc:3HNO3:1HF. Impurity selective etch preferentially etches the P ++ silicon layer 12 one hundred times faster than the lightly doped epi-silicon layer 20. This permits a controllable etch removal of P ++ substrate 12. Alternatively, a majority of the silicon wafer 12 may be removed by mechanical grinding and lapping prior to impurity selective preferential etching, for the remainder of wafer 12. A portion of epi layer 20 and thermal oxide islands 18 are controllably etched to achieve about 1,000 angstroms of gate dielectric 18 as shown in FIG. 3. This etching can be done using wet chemical etching or plasma etching.
Silicon epi layer 20, barrier layer 22 and light shield 24 are patterned and etched to form islands 26 for the fabrication of TFTs for the active matrix array and display drivers, as shown in FIGS. 4 and 5.
Spin-on-glass 28 (e.g., Allied Chemical ACCUGLASS XA03-5) is applied on substrate 14 and islands 26, and is patterned and etched as shown in FIGS. 6 and 7. Spin-on-glass 28 protects the subsequent gate 30 from shorting to the TFT channel. Also, spin-on-glass 28 planarizes the surface.
Then a polysilicon gate 30 is deposited, patterned and etched as shown in FIG. 8. This is followed by self-aligned source-drain implantation 32 of phosphorus (P 31 ), and anneal as shown in FIG. 9. The implant 32 damage is annealed at 600° C. in a furnace for 20 hours. Implant 32 conditions are selected to achieve an implant 32 range greater than the thickness of gate oxide 18. Then a silicon dioxide intermetal dielectric 34 is deposited by plasma chemical vapor deposition, patterned and the contact vias are etched down to implants 32, as shown in FIG. 10.
Aluminum (+1% Silicon) is then deposited, patterned, and etched to define the source-drain metalization 36 as shown in FIG. 11. This completes the fabrication of TFT 40 for active matrix and integrated drivers. The next step is to fabricate a pixel electrode that electrically connects to the source electrode of the active matrix pixel TFT. For AMLCDs, an Indium Tin Oxide (ITO) layer, which is a transparent conductor, is deposited, patterned and etched to define the pixel electrode. For clarity, the pixel electrode is not shown in FIGS. 11 and 12. To maintain low leakage currents under high ambient lighting conditions, another light shield 44 is placed on the top of the TFT. First a silicon dioxide passivation dielectric layer 42 is deposited on top of source-drain metalization 36. Then a second aluminum layer is deposited, patterned, and etched to obtain top light shield 44 as shown in FIG. 12.
This active matrix substrate with high mobility TFTs and integrated drivers is then utilized to fabricate high resolution AMLCDs using conventional liquid crystal display assembly techniques.
Note that the invention can also be used to fabricate integrated drivers only using the high mobility single crystal silicon TFTs, while using an a-Si or poly-Si TFT array for an active matrix. Further, the high mobility TFTs of this invention can be used to fabricate integrated drivers for TFEL and plasma display panels. Additionally, the high mobility TFTs of this invention can be used to fabricate active matrix TFEL displays with integrated drivers. In the case of an active matrix TFEL display, a reflective film such as aluminum is used as the pixel electrode. The source-drain aluminum (see FIG. 11) is used to fabricate the reflective electrode for the electroluminescent pixel.
The high mobility TFT process described above illustrates the procedures for fabricating n-channel TFTs. If p-channel TFTs are required, a similar process can be employed by changing the dopant in film 20 to phosphorus, and the source-drain implant 32 in FIG. 11 to Boron 11 (B 11 ). Also, complimentary metal oxide semiconductor (CMOS) devices, involving both n-, and p-channel TFTs on the same substrate, can be fabricated by masked implantation of the selected TFT locations (gate dielectric regions) with P 31 or B 11 after selective epitaxial deposition to create n- and p-regions, prior to electrostatic bonding. Display drivers using CMOS circuitry consume less power.
FIG. 13 shows a flow diagram for an alternate processing scheme for fabricating high mobility single crystal silicon TFTs on a display glass substrate 46 using a high quality thermal silicon dioxide gate dielectric 48. This approach is shown in FIGS. 14-18.
This process uses two single crystal silicon wafers, labelled as a silicon device wafer 50 and a silicon handle wafer 52, respectively. Both wafers 50 and 52 are of p-type with resistivity of about 1 ohm-cm, and (100) orientation. First, a high quality thermal silicon dioxide layer 48 of about a 5000 angstrom thickness is grown on wafer 52 using dry oxygen at a temperature of about 1000 degrees C. In parallel, a heavily boron doped p ++ silicon etch-stop layer 54 with a thickness of about 2 microns, and a lightly doped (p - or n - ) device layer 56 with a thickness of about 1 micron are grown on silicon device wafer 50, using silicon epitaxy. Then the two wafers, 50 and 52, are bonded to each other either by using electrostatic bonding or diffusion bonding. FIG. 14 shows a cross-section through silicon handle wafer 52 and silicon device wafer 50 prior to bonding. After bonding, silicon device wafer 50 is selectively etched away using selective chemical etch such as ethylene diamine pyrocatechol (EDP). FIG. 15 shows a cross-section through handle wafer 52 after the bonding and selective etching of device wafer 50.
Then, silicon handle wafer 52 is photolithographically patterned to etch alignment keys in silicon epi device layer 56 and thermal silicon dioxide gate dielectric 48. This allows masked implantation anneal of the n- and p- regions in device epi silicon film 56 prior to bonding to low temperature display glass substrate 46. (The alignment key fabrication and corresponding masked implantation processes are not shown.)
Next, a barrier layer 58 (about a 2500 angstrom thick plasma deposited silicon nitrite or silicon dioxide), and light shield layer 60 of about 2000 angstroms thick are deposited on top of silicon epi device layer 56 as shown in FIG. 16. This preprocessed silicon handle wafer 52 is then electrostatically bonded to display glass substrate 46 at light shield layer 60. After bonding, silicon handle wafer 52 is selectively etched away using the EDP etch or potassium hydroxide (KOH) etch. Etch rate of these etches for the thermal silicon dioxide dielectric is insignificant compared to the etch rate for handle silicon wafer 52. FIG. 17 shows a cross-section through display glass substrate 46 and accompanying layers 48, 56, 58 and 60, after silicon handle wafer 52 is selectively etched away. Then, silicon islands 62 along with thermal silicon dioxide dielectric layer 48, are patterned for the regions requiring TFTs, and etched as shown in FIG. 18. From this point on, the substrate assembly in FIG. 18 is processed similar to the first approach starting from FIG. 5. The corresponding components of devices 64 and 66 are, respectively, glass substrates 14 and 46, light shield layers 24 and 60, barrier layers 22 and 58, silicon epitaxial layers 20 and 56, silicon dioxide dielectrics 18 and 48, and islands 26 and 62.
In summary, the invention permits fabrication of TFTs having single crystal silicon for high mobility integrated drivers for active matrix displays wherein high mobility means that in excess of 300 Cm2/V.S., thermal silicon dioxide gate dielectric for low (less than 1 volt) and stable threshold voltage, and light shield for low off-currents (less than 1 pico ampere) under high ambient lighting conditions are accomplished.
The present invention may utilize variations to the basic processes, illustrated above, such as by using different thicknesses for individual layers, processing temperatures, and other processing conditions. | High mobility thin film transistors for fabricating integrated drivers for active matrix displays and a special method of fabrication for obtaining the thin film transistors having mobility sufficiently high enough as drivers operable in the several megahertz frequency range needed for driving high resolution active matrix displays. |
BACKGROUND
1. Field
The present invention generally relates to mobile phones. More specifically, the present invention relates to a method and system for prolonging emergency calls on mobile phones.
2. Related Art
Mobile phones are becoming increasingly versatile and are presently able to support a variety of applications and store large amounts of documents, media, and/or other files in various formats. For example, a high-end mobile phone may support a web browser, a portable media player, an email client, a document editor, and a global positioning system (GPS) receiver.
The various features of a mobile phone may require specific hardware components such as a high-speed processor, memory, a high-resolution display screen, multiple wireless transceivers, one or more input devices, and/or multiple sensors. Furthermore, each component on the mobile phone may require additional power from the mobile phone's battery to operate. For example, battery power may be consumed by multiple active sensors, input/output (I/O) devices, wireless transceivers, and/or software applications on the mobile phone, even when such components are not needed by the user of the mobile phone. The resulting higher consumption rate of battery power may lead to an earlier shutdown of the mobile phone, and may prevent the user from using one or more features of the mobile phone. This may create problems during emergency phone calls, in which staying connected may be critically important.
SUMMARY
Some embodiments of the present invention provide a system that processes a phone call. During operation, the system connects the phone call from a mobile phone and determines whether the phone call is an emergency call. If the phone call is an emergency call, the system activates an emergency mode of the mobile phone to handle the phone call, which prolongs the length of the phone call.
In some embodiments, the emergency mode makes the phone call harder to disconnect.
In some embodiments, the emergency mode preserves battery power on the mobile phone.
In some embodiments, the battery power is preserved by:
(i) disabling non-essential hardware components on the mobile phone, (ii) reducing power to a display screen of the mobile phone, (iii) disabling software applications on the mobile phone, or (iv) reducing processor speeds on the mobile phone.
In some embodiments, the emergency mode enables emergency phrase buttons on the mobile phone.
In some embodiments, the phone number is stored as an emergency number in the mobile phone.
In some embodiments, the emergency mode can be selected by a user of the mobile phone.
In some embodiments, the phone call is determined to be an emergency call based on a phone number associated with the phone call.
BRIEF DESCRIPTION OF THE FIGURES
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
FIG. 1 shows a schematic of a mobile phone in accordance with an embodiment of the present invention.
FIGS. 2A-2E show exemplary screenshots in accordance with an embodiment of the present invention.
FIG. 3 is a flow diagram illustrating the processing of phone calls on a mobile phone in accordance with an embodiment of the present invention.
FIG. 4 is a flow diagram of the process of activating the emergency mode in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
The following description is presented to enable any person skilled in the art to make and use the disclosed embodiments, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present description. Thus, the present description is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
The data structures and code described in this detailed description are typically stored on a computer-readable storage medium, which may be any device or medium that can store code and/or data for use by a computer system. This includes, but is not limited to, volatile memory, non-volatile memory, magnetic and optical storage devices such as disk drives, magnetic tape, CDs (compact discs), DVDs (digital versatile discs or digital video discs), or other media capable of storing computer-readable media now known or later developed.
In general, embodiments of the invention provide a method and system for processing phone calls connected from a mobile phone. Specifically, embodiments of the invention provide a method and system for prolonging emergency calls to or from the mobile phone. In one or more embodiments of the invention, an emergency mode is activated once a phone call is determined to be an emergency call. In addition, the emergency status of the phone call may be determined based on a phone number associated with the phone call, or the emergency mode may be selected by a user of the mobile phone. Once in emergency mode, the mobile phone may make the phone call harder to disconnect. The mobile phone may also enable a set of emergency phrase buttons for the user to press if the user is unable to speak. In addition, the mobile phone may preserve battery power during the emergency call by disabling non-essential hardware components, reducing power to a display screen on the mobile phone, disabling software applications, and/or reducing processor speeds.
FIG. 1 shows a schematic of a mobile phone in accordance with an embodiment of the present invention. As shown in FIG. 1 , mobile phone 102 includes an operating system 116 , an input device 128 , a wireless transceiver 130 , a display screen 132 , and multiple applications (e.g., application 1120 , application n 122 ). Each of these components is described in further detail below.
Mobile phone 102 may correspond to a portable electronic device that provides communication and other services or functions to a user. For example, mobile phone 102 may provide functionality as a communications device, portable computer, global positioning system (GPS) receiver, portable media player, and/or graphing calculator. In addition, mobile phone 102 may include an operating system 116 that coordinates the use of hardware and software resources on mobile phone 102 , as well as one or more applications (e.g., application 1 120 , application n 122 ) that perform specialized tasks for the user. For example, mobile phone 102 may include applications such as an email client, an address book, a document editor, and/or a media player. To perform tasks for the user, applications may obtain access to hardware resources (e.g., processor, memory, I/O components, wireless transceiver, etc.) on mobile phone 102 from operating system 116 . Applications may also interact with the user through a hardware and/or software framework provided by operating system 116 , as is described below.
To enable interaction with the user, mobile phone 102 may include one or more hardware input/output (I/O) components, such as input device 128 , wireless transceiver 130 , and display screen 132 . Each hardware I/O component may additionally be associated with a software driver (not shown) that allows operating system 116 and/or applications on mobile phone 102 to access and use the hardware I/O components.
Display screen 132 may be used to display images and/or text to one or more users of mobile phone 102 . In one or more embodiments of the invention, display screen 132 serves as the primary hardware output component for mobile phone 102 . For example, display screen 132 may allow the user(s) to view menus, icons, windows, emails, websites, videos, pictures, maps, documents, and/or other components of a graphical user interface (GUI) 118 provided by operating system 116 . Those skilled in the art will appreciate that display screen 132 may incorporate various types of display technology to render and display images. For example, display screen 132 may be a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, a surface-conducting electron-emitter display (SED), and/or other type of electronic display.
Input device 128 may function as the primary hardware input component of mobile phone 102 . Specifically, input device 128 may allow the user to point to and/or select one or more areas of display screen 132 using a cursor, highlight, and/or other visual indicator. Input provided by the user using input device 128 may be processed by the corresponding software driver and sent to operating system 116 and/or one or more applications (e.g., application 1 120 , application n 122 ) as one or more actions.
Input device 128 may receive user input using various methods, including touchscreens, touchpads, buttons, voice recognition, keypads, keyboards, and/or other input methods. In addition, multiple input devices may exist on mobile phone 102 . Operating system 116 and/or the application(s) (e.g., application 1 120 , application n 122 ) may use the input from the input device(s) to perform one or more tasks, as well as update GUI 118 in response. Images corresponding to GUI 118 may be sent by operating system 116 to a screen driver, which may display the images on display screen 132 as a series of pixels. As a result, the user may interact with mobile phone 102 by using input device 128 to provide input to operating system 116 and/or applications and receiving output from operating system 116 and/or applications through display screen 132 .
Wireless transceiver 130 may allow mobile phone 102 to connect to one or more wireless networks, such as wireless local area networks (LANs) and/or mobile devices networks. Mobile phone 102 may also communicate with one or more locations on the network(s) by sending and/or receiving data over the network(s) using wireless transceiver 130 . For example, mobile phone 102 may use wireless transceiver 130 to make calls, retrieve web pages, download and upload files, and send and receive emails over the network(s).
In one or more embodiments of the invention, calls placed and/or received on mobile phone 102 are connected using a communication subsystem 104 within operating system 116 . In one or more embodiments of the invention, communication subsystem 104 may include software modules that coordinate the use of telephony-associated hardware components (e.g., wireless transceiver 130 , speaker, microphone, etc.) on mobile phone 102 . Communication subsystem 104 may also implement one or more mobile communication protocols and/or standards, such as Global System for Mobile communications (GSM), code division multiple access (CDMA), generic access network (GAN), and/or General Packet Radio Service (GPRS).
As mentioned above, the user may use utilities on mobile phone 102 by interacting with GUI 118 through input device 128 and display screen 132 . To enable access to the functionality of mobile phone 102 , GUI 118 may include a variety of GUI elements, such as icons, menus, sub-menus, windows, toolbars, thumbnails, pop-ups, and/or other visual components. The GUI elements may also include text, labels, and/or text navigation to provide additional information and available actions to the user. The user may access one or more functions of mobile phone 102 through direct manipulation of one or more GUI elements. For example, the user may run an application by pointing to and selecting (e.g., double-clicking) an icon associated with the application. The user may also perform actions such as moving the cursor or visual indicator, scrolling, dragging, cutting, copying, pasting, and/or selecting an area of display screen 132 .
Those skilled in the art will appreciate that mobile phone 102 may include a large number of hardware and software components. For example, mobile phone 102 may include multiple I/O components, a high-speed processor, one or more storage devices, multiple wireless transceivers, multiple sensors, a full operating system and one or more application suites. Each hardware and/or software component may run by consuming power from a battery (not shown) within mobile phone 102 . However, the user may not use or need all hardware and/or software features of mobile phone 102 at all times.
Specifically, the user may not require the use of various applications and/or hardware components on mobile phone 102 if the user is placing or receiving an emergency call. In addition, the execution of such applications and/or hardware components may cause the battery to drain unnecessarily as the user conducts the emergency call. Further, the emergency call may end prematurely if the battery runs out of power from such elevated rates of consumption by one or more components on mobile phone 102 .
In one or more embodiments of the invention, communication subsystem 104 includes an emergency-mode processor 106 to process emergency calls. Emergency-mode processor 106 may determine if a phone call made or received by mobile phone 102 is an emergency call. If the phone call is an emergency call, emergency-mode processor 106 may activate an emergency mode of the mobile phone to handle the phone call. Further, the emergency mode may include mechanisms to prolong the length of the emergency call and avert premature termination of the emergency call.
In particular, the emergency-mode processor 106 may determine an emergency call based on a phone number associated with the phone call. For example, calls to well-known emergency numbers such as 911 may be automatically classified as emergency calls. The user may also specify a set of emergency numbers, which are stored in an emergency number list 108 . Calls made to phone numbers on emergency number list 108 may also be classified as emergency calls by emergency-mode processor 106 . On the other hand, the user may manually specify an emergency call by, for example, pressing a button, entering a code corresponding to the emergency mode, and/or providing other input using input device 128 .
Once the emergency mode is activated, emergency-mode processor 106 may perform one or more actions to prolong the emergency call. To prevent an inadvertent end to the emergency call, emergency-mode processor 106 may make the emergency call harder to disconnect. For example, if the user presses a button to disconnect an emergency call, emergency-mode processor 106 may query the user for confirmation before disconnecting the call. The confirmation may be in the form of a button, a code or password, a verbal acknowledgement, and/or other input by the user. Emergency-mode processor 106 may even disable the user's ability to disconnect the call. As a result, the call may only be disconnected by someone (e.g., an emergency operator) on the other end of the emergency call. Further, the user may select settings to specify the level of difficulty and the methods of disconnecting emergency calls. The user may also select settings for each individual emergency number. For example, the user may disable the ability to disconnect a 911 call while activating a disconnect confirmation in other emergency calls.
Emergency-mode processor 106 may also preserve battery power on mobile phone 102 . In one or more embodiments of the invention, battery power may be preserved by disabling non-essential hardware components, reducing power to display screen 132 , disabling software applications, and/or reducing processor speeds. A non-essential hardware component may correspond to any hardware component that is not necessary for the emergency call to be conducted. For example, non-essential hardware components may include Bluetooth and Wi-Fi transceivers, secondary I/O devices, and/or camera sensors. However, hardware components that may be helpful in emergency situations, such as a GPS transceiver, may continue to be active in emergency mode.
Furthermore, emergency-mode processor 106 may enable emergency phrase buttons on mobile phone 102 . The emergency phrase buttons may be shown on display screen 132 , for example. Alternatively, the user may program various input devices on mobile phone 102 to correspond to one or more emergency phrase buttons. In one or more embodiments of the invention, the emergency phrase buttons are used by the user to communicate in the emergency call if the user is unable to speak. In one or more embodiments of the invention, the emergency phrase buttons allow preset and/or pre-recorded audio clips of phrases to be played in the emergency call. The phrases may be provided by mobile phone 102 and/or specified by the user. In addition, the phrases may be stored as audio files in mobile phone 102 or generated in real-time using a speech synthesizer on mobile phone 102 . For example, if the user is choking, the user may press an emergency phrase button that states his/her physical condition to a 911 operator. The user may also press buttons to communicate other information, such as his/her location, and/or request the 911 operator to contact a friend and/or family member.
FIG. 2A shows an exemplary screenshot of an emergency call in accordance with an embodiment of the present invention. The screenshot is shown on a display screen 204 of a mobile phone 202 . In one or more embodiments of the invention, the screenshot corresponds to an emergency mode of mobile phone 202 after the user has placed an emergency call. As shown in FIG. 2A , a phone number 206 of the emergency call corresponds to 911. Phone number 206 may be dialed by the user or connected to the user via an incoming call. As mentioned above, phone number 206 may be classified as an emergency number by mobile phone 202 , or phone number 206 may be specified as an emergency number by the user. In one or more embodiments of the invention, emergency numbers provided by the user are stored in an emergency number list within mobile phone 202 . Calls made to or from numbers on the emergency number list may be classified as emergency calls by mobile phone 202 .
As shown in FIG. 2A , the screenshot also includes a disconnect feature 208 that allows the user to end the emergency call. Disconnect feature 208 may be activated, for example, by contacting a region of display screen 204 corresponding to disconnect feature 208 , using a voice command, interacting with a wired or wireless headset in communication with mobile phone 202 , and/or using other input methods. However, disconnect feature 208 may be disabled when mobile phone 202 is in emergency mode. Alternatively, the user may be prompted to confirm the disconnection of the call, as shown in FIG. 2B .
FIG. 2B shows an exemplary screenshot of an emergency call in accordance with an embodiment of the present invention. In FIG. 2B , disconnect feature 208 has been activated by the user. However, because mobile phone 202 is in emergency mode, a disconnect confirmation 210 is displayed to the user. In one or more embodiments of the invention, disconnect confirmation 210 is used to prevent inadvertent disconnection of emergency calls. For example, the user may inadvertently activate disconnect feature 208 by accidentally contacting one or more areas of display screen 204 corresponding to disconnect feature 208 .
To disconnect the call, the user may press button 212 . To remain on the call, the user may press button 214 . In one or more embodiments of the invention, the emergency call continues until the user has pressed button 212 or the call is disconnected from the other end. In other words, the emergency call is not interrupted if the user accidentally presses the disconnect feature 208 button. Alternatively, mobile phone 202 may include other mechanisms for confirming or canceling disconnect feature 208 . For example, mobile phone 202 may accept a voice command corresponding to the confirmation or cancellation of disconnect feature 208 by the user. As described above, the voice command may be spoken into a microphone on mobile phone 202 or into a wired or wireless headset connected to mobile phone 202 .
FIG. 2C shows an exemplary screenshot of an emergency call in accordance with an embodiment of the present invention. In FIG. 2C , the user has activated an emergency phrase prompt 216 during the call. As with other elements of the emergency call, emergency phrase prompt 216 may be activated by using one or more input devices on mobile phone 202 , using a voice command, and/or using other input methods. Emergency phrase prompt 216 includes a set of emergency phrase buttons 218 - 222 for the user to press.
As described above, emergency phrase buttons 218 - 222 may be used by the user to communicate in the emergency call if the user is unable to speak. Emergency phrase buttons 218 - 222 may be provided by mobile phone 202 and/or added by the user. Specifically, emergency phrase buttons 218 - 222 may enable playback of preset and/or pre-recorded audio clips of phrases during the emergency call. Moreover, the phrases may be stored as audio files in mobile phone 102 and/or generated in real-time using a speech synthesizer on mobile phone 102 .
For example, emergency phrase button 218 may play a preset message that communicates the user's location (e.g., geographic coordinates, street intersection, etc.) into the phone call. As mentioned above, hardware components on mobile phone 202 that may be helpful in an emergency situation may remain active during the emergency call. As a result, the user's location may be established using a GPS transceiver, wireless transceiver, and/or other active hardware component on mobile phone and appended to the phrase corresponding to emergency phrase button 218 .
Emergency phrase button 220 may play a preset or prerecorded message communicating the user's inability to speak during the emergency call. The message may be provided by mobile phone 202 and/or recorded by the user. In addition, the message may generically state the user's inability to speak, or the message may be customized to provide additional detail, such as a specific physical condition, that prevents the user from speaking.
Emergency phrase button 222 may play a preset or prerecorded message communicating an asthma attack currently experienced by the user. As with emergency phrase buttons 218 - 220 , the message corresponding to emergency phrase button 222 may be prerecorded and/or preset. In addition, the message may contain additional information, such as descriptions of effective treatments for the user's asthma attacks.
FIG. 2D shows an exemplary screenshot of a contact group list in accordance with an embodiment of the present invention. Display screen 204 shows a set of groups 216 - 226 associated with contacts stored on mobile phone 202 . Contacts in each group may be classified based on a common attribute. For example, contacts stored in group 226 may correspond to restaurants visited by the user. Similarly, all contacts of the user may be accessed using group 218 .
In one or more embodiments of the invention, Group 216 corresponds to an emergency number list. As described above, the user may add emergency numbers to the emergency number list. When calls are made to and/or from the emergency number list, mobile phone 202 may activate an emergency mode to prolong the length of the call. The numbers stored in the emergency number list may include, for example, police stations, fire stations, medical emergency lines, crisis hotlines, emergency family numbers, and/or work-related numbers.
FIG. 2E shows an exemplary screenshot of a contact in accordance with an embodiment of the present invention. As shown in FIG. 2E , the contact is associated with three phone numbers 228 - 232 and an emergency number 234 . The user may make or receive calls to or from phone numbers 228 - 232 in a normal operating mode of mobile phone 202 . However, if the user is connected to a call with emergency number 234 , mobile phone 202 may activate an emergency mode to prolong the length of the call, as described above.
In one or more embodiments of the invention, emergency number 234 is also stored in an emergency number list. In addition, the user may specify settings with respect to emergency number 234 . For example, the user may enable or disable an ability to disconnect calls with emergency number 234 , or the user may increase the difficulty of disconnecting calls with emergency number 234 . The user may also specify emergency phrase buttons that are enabled when a call with emergency number 234 is made. As mentioned previously, the emergency phrase buttons may allow the user to communicate with emergency number 234 if the user is unable to speak.
FIG. 3 is a flow diagram illustrating the processing of phone calls on a mobile phone in accordance with an embodiment of the present invention. In one or more embodiments of the invention, one or more of the steps may be omitted, repeated, and/or performed in a different order. Accordingly, the specific arrangement of steps shown in FIG. 3 should not be construed as limiting the scope of the invention.
Initially, a phone call request is received (operation 302 ). The phone call request may correspond to an incoming or outgoing call to or from a mobile phone. The phone call is then connected (operation 304 ) by the mobile phone. A determination may be made regarding whether the phone call is an emergency (operation 306 ). As described above, the phone call may be classified as an emergency based on a phone number associated with the call. For example, the phone number may be a well-known emergency number, such as 911. The phone number may also be specified by the user in an emergency number list in the mobile phone. Alternatively, the user may manually designate a call as an emergency by pressing a button, using a voice command, and/or providing other input upon connecting the call. If the call is an emergency, an emergency mode is activated (operation 308 ). If the call is a normal call, the emergency mode is not activated and the call is conducted normally.
FIG. 4 is a flow diagram of the process of activating the emergency mode in accordance with an embodiment of the present invention. In one or more embodiments of the invention, one or more of the steps may be omitted, repeated, and/or performed in a different order. Accordingly, the specific arrangement of steps shown in FIG. 4 should not be construed as limiting the scope of the invention.
First, the phone call is made harder to disconnect (operation 402 ). This may be done by prompting the user to confirm a disconnect feature of the mobile phone or by disabling the disconnect feature altogether. Battery power in the mobile phone may also be preserved (operation 404 ). As mentioned previously, battery power may be preserved by disabling non-essential hardware components, reducing power to the mobile phone's display screen, disabling software applications on the mobile phone, and/or reducing processor speeds on the mobile phone. Finally, emergency phrase buttons may be enabled (operation 406 ) on the mobile phone. The emergency phrase buttons may allow the user to communicate over the phone call when he/she is unable to talk. As described above, the emergency phrase buttons may correspond to pre-recorded and/or preset phrases that are played when the buttons are pressed. In addition, the phrases may be provided by the mobile phone or programmed into the mobile phone by the user.
The foregoing descriptions of embodiments have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the present invention to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners skilled in the art. Additionally, the above disclosure is not intended to limit the present invention. The scope of the present invention is defined by the appended claims. | Some embodiments of the present invention provide a system that processes a phone call. During operation, the system connects the phone call from a mobile phone and determines whether the phone call is an emergency call. If the phone call is an emergency call, the system activates an emergency mode of the mobile phone to handle the phone call, which prolongs the length of the phone call. |
BRIEF SUMMARY OF THE INVENTION
This invention relates generally to fluid drop ejectors and method of operation, and more particularly to fluid drop ejectors wherein the drop size, number of drops, speed of ejected drops, and ejection rate are controllable.
BACKGROUND OF THE INVENTION
Fluid drop ejectors have been developed for inkjet printing. Nozzles which allow the formation and control of small ink droplets permit high resolution, resulting in printing sharper characters and improved tonal resolution. Drop-on-demand inkjet printing heads are generally used for high-resolution printers.
In general, drop-on-demand technology uses some type of pulse generator to form and eject drops. In one example, a chamber having an ink nozzle is fitted with a piezoelectric wall which is deformed when a voltage is applied. As a result, the fluid is forced out of the nozzle orifice and impinges directly on an associated printing surface. Another type of printer uses bubbles formed by heat pulses to force fluid out of the nozzle. The drops are separated from the ink supply when the bubbles collapse.
There is a need for an improved fluid drop ejector for use not only in printing, but also, for photoresist deposition in the semiconductor and flat panel display industries, drug and biological sample delivery, delivery of multiple chemicals for chemical reactions, DNA sequences, and delivery of drugs and biological materials for interaction studies and assaying, and a need for depositing thin and narrow layers of plastics for use as permanent and removable gaskets in micro-machines. There is also need for a fluid ejector that can cover large areas with little or no mechanical scanning.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved fluid drop ejector.
It is another object of the invention to provide a fluid drop ejector in which the ejected fluid, drop size, drop velocity, ejection rate and number of drops can be easily controlled.
It is a further object of the invention to provide a fluid drop ejector which can be micro-machined.
It is another object of the invention to provide a fluid drop ejector which can be micro-machined to provide a selectively excitable matrix of membranes having nozzles for ejection of fluid drops.
It is a further object of the invention to provide a fluid drop ejector in which a membrane including a nozzle is actuated to eject droplets of fluid, at or away from the mechanical resonance of the membrane.
The foregoing and other objects are achieved by a fluid drop ejector which includes a fluid reservoir with one wall comprising a thin, elastic membrane having an orifice defining a nozzle. The membrane is adapted to mechanically vibrate on application of bending forces applied preferentially at its resonant frequency. When said reservoir contains fluid, the membrane deflects to form and eject drops at the nozzle. The reservoir is not necessarily full of fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects of the invention will be more fully understood from the following description read in connection with the accompanying drawings, wherein:
FIG. 1 is a sectional view of a drop-on-demand fluid drop ejector in accordance with the invention including a piezoelectrically driven membrane;
FIG. 2 is a top plan view of the ejector shown in FIG. 1;
FIG. 3 is a sectional view of a drop-on-demand fluid drop ejector in accordance with another embodiment of the invention;
FIGS. 4A-4C show the ac voltage applied to the piezoelectric transducer of FIGS. 1 and 2, the mechanical oscillation of the membrane, and continuous ejection of fluid drops;
FIGS. 5A-5C show the application of ac voltage pulses to the piezoelectric transducer of FIGS. 1 and 2, the mechanical oscillation of the membrane and the drop-on-demand ejection of drops;
FIGS. 6A-6C show the first three mechanical resonant modes of a membrane as examples among all the modes of superior order in accordance with the invention;
FIGS. 7A-7D show the deflection of the membrane responsive to the application of an excitation ac voltage;
FIG. 8 is a side elevational view of a fluid drop ejector wherein the membrane is electrostatically oscillated;
FIG. 9 shows another embodiment of an electrostatically oscillated membrane;
FIG. 10 shows a fluid drop ejector in which the membrane is oscillated by a magnetic driver;
FIGS. 11A-11D show the steps in the fabrication of a matrix of fluid drop ejectors of the type shown in FIGS. 1 and 2;
FIG. 12 is a top plan view of a matrix fluid drop ejector formed in accordance with the process of FIGS. 11A-11D;
FIGS. 13A-13C show the steps in the fabrication of a matrix of electrostatic fluid drop ejectors;
FIG. 14 is a top plan view of the fluid drop ejector shown in FIG. 12;
FIG. 15 is a bottom plan view of the fluid drop ejector shown in FIG. 12; and
FIG. 16 shows another embodiment of a matrix fluid drop ejector.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A fluid drop ejector according to one embodiment of this invention is shown in FIGS. 1 and 2. The ejector includes a support body or substrate 11 which can have apertures for the supply of fluid. A cylindrical wall 12 supports an elastic membrane 13. The support 11, wall 12 and membrane 13 define a fluid reservoir 14. An aperture 16 may be formed in the wall 12 to permit continuous supply of fluid into the reservoir to replenish fluid which is ejected, as will be presently described. The supply opening could be formed in the support body or substrate 11 or its apertures. A piezoelectric annular disk 17 is attached to or formed on the upper surface of the membrane 13. The disk 17 includes conductive contact films 18 and 19. The piezoelectric film can also be formed on the bottom surface of the membrane, or can itself be the membrane.
In accordance with the invention, the membrane is driven so that it mechanically oscillates preferably into resonance. This is illustrated in FIGS. 4 through 6. FIG. 4A shows a sine wave excitation voltage which is applied to the piezoelectric transducer. The transducer applies forces to the membrane responsive to the applied voltage. FIG. 4B shows the amplitude of deflection at the center of the membrane responsive to the applied forces. It is noted that when the power is first applied, the membrane is only slightly deflected by the first power cycle, as shown at 22, FIG. 4B. The deflection increases, whereby, in the present example, at the third cycle, the membrane is in maximum deflection, as shown at 23, FIG. 4B. At this point, its deflection cyclically continues at maximum deflection with the application of each cycle of the applied voltage, and permits the ejection of each corresponding drop, as shown in FIG. 4C. When the power is turned off, the membrane deflection decays as shown at 24, FIG. 4B. The frequency at which the membrane resonates is dependent on the membrane material, its elasticity, thickness, shape and size. The shape of the membrane is preferentially circular; however, the other shapes, such as square, rectangular, etc., can be made to resonate and eject fluid drops. In particular, an elliptic membrane can eject two drops from its focal points at resonance. The amount of deflection depends on the magnitude of the applied power. FIG. 6 shows, for a circular membrane, that the membrane may have different modes of resonant deflection. FIG. 6A shows deflection at its fundamental frequency; FIG. 6B at the first harmonic and FIG. 6C at the second harmonic.
The action of the membrane to eject drops of fluid is illustrated in FIGS. 7A-7D. These figures represent the deflection at the fundamental resonance frequency. FIG. 7A shows the membrane deflected out of the reservoir, with the liquid in contact with the membrane. FIG. 7B shows the membrane returning to its undeflected position, and forming an elongated bulb of fluid 26 at the orifice nozzle. FIG. 7C shows the membrane extending into the reservoir and achieving sufficient velocity for the bulb to cause it to break away from the body of fluid 26 and form a drop 27 which travels in a straight line away from the membrane and nozzle toward an associated surface such as a printing surface. FIG. 7D represents the end of the cycle and the shape of the fluid bulb at that point.
Referring to FIG. 4C, it is seen that the membrane reaches maximum deflection upon application of the third cycle of the applied voltage. It then ejects drops with each cycle of the applied voltage as long as the applied voltage continues. FIGS. 5A-5C show the application of excitation pulses. At 29, FIG. 5A, a four-cycle pulse is shown applied, causing maximum deflection and ejection of two single drops. The oscillation then decays and no additional drops are ejected. At 30, three cycles of power are applied, ejecting one drop. It is apparent that drops can be produced on demand. The drop rate is equal to the frequency of the applied excitation voltage. The drop size is dependent on the size of the orifice and the magnitude of the applied voltage. The fluid is preferably fed into the reservoir at constant pressure to maintain the meniscus of the fluid at the orifice in a constant concave, flat, or convex shape, as desired. The fluid must not contain any air bubbles, since it would interfere with operation of the ejector.
FIG. 3 shows a fluid drop ejector which has an open reservoir 14a. The weight of the fluid keeps it in contact with the membrane. The bulb 26a is ejected due to the suppression caused by deflection of the membrane 13 into the fluid.
A fluid drop ejector of the type shown in FIG. 3 was constructed and tested. More particularly, the resonant membrane comprised a circular membrane of steel (0.05 mm in thickness; 25 mm in diameter, having a central hole of 150 μm in diameter). This membrane was supported by a housing composed of a brass cylinder with an outside diameter of 25 mm and an inside diameter of 22.5 mm. The membrane was actuated by an annular piezoelectric plate bonded on its bottom and on axis to the circular membrane. The annular piezoelectric plate had an outside diameter of 23.5 mm and an inside diameter of 18.8 mm. Its thickness was 0.5 mm. The reservoir was formed by the walls of the housing and the top was left open to permit refilling with fluid. The device so constructed ejected drops of approximately 150 μm in diameter. The ejection occurred when applying an alternative voltage of 15 V peak to the piezoelectric plate at a frequency of 15.5 KHz (with 0.3 KHz tolerance of bandwidth), which corresponded to the resonant frequency of the liquid loaded membrane. This provided a bending motion of the membrane with large displacements at the center. Thousands of identical drops were ejected in one second with the same direction and velocity. The level of liquid varied from 1-5 mm with continuous ejection while applying a slight change in frequency to adapt to the change in the resonant frequency of the composite membrane due to different liquid loading. When the level of liquid remained constant, the frequency of drop formation remained relatively constant. The excitation was sinusoidal, although square waves and triangular waveforms were used as harmonic signals and also gave continuous drop ejection as the piezoelectric material was excited.
As will be presently described, the fluid drop ejector can be implemented using micro-machining technologies of semiconductor materials. The housing could be silicon and silicon oxide, the membrane could be silicon nitride, and the piezoelectric could be a deposited thin film such as zinc oxide. In this manner, the dimensions of an ejector could be no more than 100 microns and the orifice could be anywhere from a few to tens of microns. Two-dimensional matrices can be easily implemented for printing at high speed with little or no relative motion between the fluid drop ejector and object upon which the fluid is to be deposited.
The membrane can be excited into resonance with other types of drivers. For example, FIG. 7 shows an ejector in which the membrane is electrostatically vibrated. The membrane 31 may be of silicon nitride with a conductive film 32. The membrane is spaced from the substrate 33 by an insulating oxide ring 34; a conductive film 36 is applied to the lower surface of the substrate. Thus, when voltage is applied between the two conductive films, it induces a force proportional to the square of the electric field between the two conductive films 32, 36. The added simplicity of not needing a piezoelectric transducer is quite important; however, such a design will only work for fluids that are non-conductive. Micro-machining such a device will be described below.
FIG. 9 shows an electrostatic fluid drop ejector which can be used to eject conductive fluids. The same reference numbers have been applied to parts corresponding to FIG. 8. The fluid drop ejector of FIG. 9 includes an insulating support 37 which supports a rigid conductive member 38 spaced from the film 32. Voltage applied between the conductive member 37 and conductive film 32 will give rise to forces proportional to the square of the electric field therebetween. These forces will serve to deflect the membrane 31.
FIG. 10 illustrates a device similar to that of FIGS. 8 and 9, where like reference numbers have been applied to like parts. However, the transducer 39 is a magnetic transducer electrically driven to deflect and bring into resonance the membrane 31. This transducer can also be driven magnetically or electrically by another transducer placed at a distance such as behind a piece of paper.
Referring to FIGS. 11A-11D, the steps of forming a micro-machined matrix of fluid drop ejectors of the type shown in FIGS. 1 and 2 from semiconductor material are shown. By well-known semiconductor film or layer-growing techniques, a silicon substrate 41 is provided with successive layers of silicon oxide 42, silicon nitride 43, metal 44, piezoelectric material 45 and metal 46. The next steps, shown in FIG. 11B, are to mask and etch the metal film 46 to form disk-shaped contacts 48 having a central aperture 49 and interconnected along a line. The next step is to etch the piezoelectric layer in the same pattern to form transducers 51. The next step is to mask and etch the film 44 to form disk-shaped contacts 52 having central apertures 53 and interconnected along columns 55, FIG. 12. The next steps, FIG. 11D, are to mask and etch orifices 54 in the silicon nitride layer 43. This is followed by selectively etching the silicon oxide layer 42 through the orifices 54 to form a fluid reservoir 56. The silicon nitride membrane is supported by silicon oxide posts 57.
FIG. 12 is a top plan view of the matrix shown in FIGS. 11A-11D. The dotted outline shows the extent of the fluid reservoir. It is seen that the membrane is supported by the spaced posts 57. The lower contacts of the piezoelectric members in the horizontal rows are interconnected as shown and the upper contacts of the piezoelectric members in the columns are interconnected as shown, thereby giving a matrix in which the individual ejectors can be excited, thereby ejecting selected patterns of drops. By micro-machining, closely spaced patterns of orifices or nozzles can be achieved. If the spacing between orifices is 100 μm, the matrix will be capable of simultaneously depositing a resolution of 254 dots per inch. If the spacing between orifices is 50 μm, the matrix will be capable of simultaneously depositing a resolution of 508 dots per inch. Such resolution would be sufficient to permit the printing of lines or pages of text without the necessity of relative movement between the print head and the printing surface.
The steps of forming a matrix, including electrostatic excited fluid drop ejectors of the type shown in FIG. 9, are illustrated in FIGS. 13A-13C. The first step is to start with the highly doped polysilicon wafer 61 which serves as the substrate. The next steps are to grow a thick layer (1-10 μm) of oxide 62 thermally or by chemical vapor deposition or any other IC processing method, followed by the deposition of a 7500 Å-thick layer of low-stress LPCVD silicon nitride 63. The back side of the wafer is stripped of these layers and a 500 Å film of gold 64 is evaporated on both sides of the wafer. The resulting structure is shown in FIG. 13A. A resist pattern of 2 μm diameter dots on a two-dimensional grid with 100 μm period is transferred lithographically to the wafer. The gold and nitride are etched through the dots by using a suitable chemical etch for the gold and a plasma etch for the nitride. The resulting structure is shown in FIG. 13B. The holes 66 provide access to silicon dioxide which acts as a sacrificial layer. The sacrificial layer is etched away by pure hydrofluoric acid during a timed etch. This leaves a portion 67 of the thermal oxide layer supporting the silicon nitride membrane. The size of the unsupported silicon nitride membrane is controlled by the etch time. However, if processing were terminated at this point, the surface tension between the liquid etchant and the silicon nitride layer would pull the nitride membrane down as the etchant is removed. Once the nitride and silicon are in contact, Vander Wals forces would hold the membrane to the silicon substrate and the device would no longer function. Two different techniques can be employed to prevent this from occurring. First, chemically roughening the silicon surface to reduce the surface area to which the membrane is exposed and thus, reduce the Vander Wals forces holding the membrane. The preferred chemical etchant is potassium hydroxide and is an anisotropic silicon etchant. After 20 minutes of etching, pyramidal posts are left on the silicon surface. The second step used for preventing sticking is to freeze-dry the structure; this results in the liquid etch sublimating instead of evaporating. The patterned upper metal film is interconnected along rows as shown in FIG. 14 and the bottom film is patterned and interconnected in columns as shown in FIG. 15. This provides a means for individually addressing the individual fluid drop ejectors to electrostatically eject a dot pattern.
The invention has been described in connection with the ejection of a single fluid as, for example, for printing a single color or delivering a single biological material or chemical. It is apparent that ejectors can be formed for ejecting two or more fluids for color printing and chemical or biological reactions. The spacing of the apertures and the size and location of the associated membranes can be selected to provide isolated columns or rows of interconnected reservoirs. Adjacent rows or columns can be provided with different fluids. An example of a matrix of fluid ejectors having isolated rows of fluid reservoirs is shown in FIG. 16. The fluid reservoirs 56a are interconnected along rows 71. The rows are isolated from one another by the walls 57a. Thus, each of the rows of reservoirs can be supplied with a different fluid. Individual ejectors are energized by applying voltages to the interconnections 58a and 59a. The illustrated embodiment is formed in the same manner as the embodiment of FIG. 12. It is apparent that spacing of apertures and reservoirs of the embodiment of FIGS. 14 and 15 can be controlled to form isolated rows or columns of reservoirs and apertures to provide for delivery of multiple fluids. The processing of the fluid drop ejector assembly of FIGS. 14 and 15 can be controlled so that there are individual fluid reservoirs with individual isolated membranes. | An improved fluid drop ejector is disclosed which includes one wall including a thin elastic membrane having an orifice defining a nozzle and elements responsive to electrical signals for deflecting the membrane to eject drops of fluid from the nozzle. |
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation of U.S. Ser. No. 10/925,827, filed Aug. 25, 2004, (issued as U.S. Pat. No. 7,134,502 on Nov. 14, 2006) which is incorporated herein by reference and priority to which is hereby claimed, which claimed priority to U.S. Provisional patent application No. 60/498,215 filed Aug. 27, 2003.
This is a continuation of U.S. Ser. No. 11/599,170, filed Nov. 14, 2006, (issued as U.S. Pat. No. 7,373,987 on May 20, 2008) which is incorporated herein by reference and priority to which is hereby claimed.
This is a continuation of U.S. Ser. No. 12/123,607, filed May 20, 2008 now U.S. Pat. No. 7,469,747, which is incorporated herein by reference and priority to which is hereby claimed.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
REFERENCE TO A “MICROFICHE APPENDIX”
Not applicable
BACKGROUND
The present invention relates generally to drilling fluid recovery and, more specifically, to a system for preventing fluids from being spilled when casing is being finished for a well bore.
The process of drilling subterranean wells to recover oil and gas from reservoirs, consists of boring a hole in the earth down to the petroleum accumulation in the reservoir, and installing pipe from the reservoir to the surface. Casing is a protective pipe liner within the well bore that is cemented in place to insure a pressure-tight connection to the oil and gas reservoir. The casing can be run from the rig floor as it is lowered into the well bore.
When running casing, drilling fluid is added to each section as it is run into the well. This procedure is necessary to prevent the casing from collapsing due to high pressures within the well bore. The drilling fluid acts as a lubricant which facilitates lowering the casing within the well bore.
Drilling fluid, or drilling mud, is very important to the rotary drilling process. Drilling and completion fluids which include fluids such as weighted mud, oil-based fluids, water-based muds and the like are often quite expensive and may frequently cost more than one million dollars per well. It is basically a mixture of water, clay, and special minerals and chemicals and performs many important functions. For example, drilling fluid exerts pressure inside the hole keeping fluids that may be in the formations from entering the hole and perhaps blowing out to the surface. In addition, pressure in the hole forces solid particles of clay in the mud to adhere to the sides of the hole as the drilling fluid circulates upward on its way to the surface. The solids form a thin, impermeable cake on the walls of the hole. If discharged drilling fluids can be hazardous to the environment.
The normal sequence for running casing involves suspending the casing from a top drive or non-top drive (conventional rotary rig) and lowering the casing into the well bore, filling each joint of casing with drilling fluid. The filling of each joint or stand of casing as it is run into the hole is the fill-up process. Lowering the casing into the well bore is facilitated by alternately engaging and disengaging elevator slips and spider slips with the casing string in a stepwise fashion, facilitating the connection of an additional stand of casing to the top of the casing string as it is run into the hole.
Circulation of the fluid is sometimes necessary if resistance is encountered as the casing is lowered into the well bore, preventing the running of the casing string into the hole. This resistance to running the casing into the hole may be due to such factors as drill cuttings, mud cake, or surface tension formed or trapped within the annulus between the well bore and the outside diameter of the casing, or caving of the well bore among other factors. In order to circulate the drilling fluid, the top of the casing must be sealed so that the casing may be pressurized with drilling fluid. Since the casing is under pressure the integrity of the seal is critical to safe operation, and to minimize the loss of expensive drilling fluid. Once the obstruction is removed the casing may be run into the hole as before.
Once the casing reaches the bottom, circulating of the drilling fluid is again necessary to test the surface piping system, to condition the drilling fluid in the hole, and to flush out wall cake and cuttings from the hole. Circulating is continued until at least an amount of drilling fluid equal to the volume of the inside diameter of the casing has been displaced from the casing and well bore. After the drilling fluid has been adequately circulated, the casing may be cemented in place.
After the casing has been run to the desired depth it may be cemented within the well bore. The purpose of cementing the casing is to seal the casing to the well bore formation. In order to cement the casing within the well bore, the assembly to fill and circulate drilling fluid is generally removed from the drilling rig and a cementing head apparatus installed. A special cementing head or plug container is installed on the top portion of the casing being held in place by the elevator. Since the casing and well bore are full of drilling fluid, it is first necessary to inject a spacer fluid to segregated the drilling fluid from the cement to follow. The cementing plugs are used to wipe the inside diameter of the casing and serves to separate the drilling fluid from the cement, as the cement is carried down the casing string. Once the calculated volume of cement required to fill the annulus has been pumped, the top plug is released from the cementing head. Drilling fluid or some other suitable fluid is then pumped in behind the top plug, thus transporting both plugs and the cement contained between the plugs to an apparatus at the bottom of the casing known as a float collar. Once the bottom plug seals the bottom of the casing, the pump pressure increases, which ruptures a diaphragm in the bottom of the plug. This allows the calculated amount of cement to flow from the inside diameter of the casing to a certain level within the annulus being cemented. The annulus is the space within the well bore between the ID of the well bore and the OD of the casing string. When the top plug comes in contact with the bottom plug, pump pressure increases, which indicates that the cementing process has been completed. Once the pressure is lowered inside the casing, a special float collar check valve closes, which keeps cement from flowing from the outside diameter of the casing back into the inside diameter of the casing. At this point the casing is filled with drilling fluid.
After being run the casing must be cut and finished at an appropriate level to install rig equipment such as blow out preventers along with other equipment. However, because of earlier operations, the entire length of casing is typically filled with drilling fluid. Depending on conditions, the length of casing which is to be cut and removed may therefore over a 100-foot (27.4 meter) column of drilling fluid therein. The drilling fluid in this section must be properly drained before the casing is cut and removed.
Prior art systems for removal of the drilling fluid in the casing have consisted of cutting an opening in the casing with a casing cutter, using tarpolines and a pan in an attempt to contain the escaping column of drilling fluid in the casing to be removed. Unfortunately, the prior art systems have been slow (taking up to many hours to drain) and allowing drilling fluid to and escape into the environment creating potential environmental hazards, such as pollution. Additionally, loss of fluids can be costly as the fluids are expensive and must be replaced.
While certain novel features of this invention shown and described below are pointed out in the annexed claims, the invention is not intended to be limited to the details specified, since a person of ordinary skill in the relevant art will understand that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation may be made without departing in any way from the spirit of the present invention. No feature of the invention is critical or essential unless it is expressly stated as being “critical” or “essential.”
BRIEF SUMMARY
The apparatus of the present invention solves the problems confronted in the art in a simple and straightforward manner. What is provided is a fluid recovery system for recovering drilling fluid when cutting casing, such as a recovery system mountable on one or more joints of casing, a receiving tank, and a conduit between the recovery system and the receiving tank. A valve may preferably be provided for controlling flow through the conduit.
The method of the invention may preferably comprise steps such as the steps of mounting a recovery system on a joint of casing, creating a hole in the joint, and collecting the fluid in a receiving tank. The method may further comprise cutting the casing and removing the stand of casing above the cut.
The present invention provides a more efficient operation significantly improving the speed of draining drilling fluid, improving safety, and reducing well fluid loss into the environment.
It is an object of the present invention to provide an improved fluid recovery system.
Another object of the present invention is to have the ability to reduce the time required for setting up the well bore fluid recovery system.
Another object of the present invention is to have the ability to reduce any discharge of drilling fluids.
These and other objects, features, and advantages of the present invention will become apparent from the drawings, the descriptions given herein, and the appended claims. The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:
FIG. 1 is a schematic view of the prior art system for recovering drilling fluid.
FIG. 2 is a schematic view of a preferred embodiment of the present invention being used to recover drilling fluid.
FIG. 3 is a perspective view of the recovery system in FIG. 2 .
FIG. 4 is a perspective view of the body of the recovery system in FIG. 3 .
FIG. 4A is a perspective view of the drill used in the recovery system shown in FIG. 3 .
FIG. 5 is a side view of the body of the recovery system in FIG. 3 .
FIG. 6 is a perspective view of the mounting rack for the recovery system in FIG. 3 .
FIG. 7 is a perspective view of a portion of the recovery system in FIG. 2 .
FIG. 8 is a perspective view of a shaft and drill bit for the recovery system in FIG. 2 .
FIG. 9 is an exploded view of the shaft and drill bit for the recovery system in FIG. 2 .
FIG. 10 is a top view of a portion of the recovery system in FIG. 2 .
FIG. 11 is a perspective view of a portion of the recovery system in FIG. 2 .
FIG. 12 is a side view of a portion of the clamp of the recovery system in FIG. 2 .
FIG. 13 is an end view of the coupling of the recovery system in FIG. 2 .
DETAILED DESCRIPTION
Detailed descriptions of one or more preferred embodiments are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in any appropriate system, structure or manner.
It will be understood that such terms as “up,” “down,” “vertical” and the like are made with reference to the drawings and/or the earth and that the devices may not be arranged in such positions at all times depending on variations in operation, transportation, and the like. As well, the drawings are intended to describe the concepts of the invention so that the presently preferred embodiments of the invention will be plainly disclosed to one of skill in the art but are not intended to be manufacturing level drawings or renditions of final products and may include simplified conceptual views as desired for easier and quicker understanding or explanation of the invention. As well, the relative size of the components may be greatly different from that shown, e.g., a recovery or well bore fluid storage tank 120 , discussed below, may typically be much larger than as shown.
FIG. 1 is a schematic view of a prior art system for recovering drilling fluid 105 . A casing cutter 400 is used to make a cut in casing 20 . Column of drilling fluid or mud 104 located in upper section of casing 30 above the cut is then drained in pan 420 . Pan 420 can be placed on deck 70 . Tarpoline 410 is placed over the cut in an attempt to minimize the loss of drilling fluid 106 . Such prior art method is slow, taking up to several hours to drain column of drilling fluid 104 and can require the presence of three to four rig hands. Additionally, there is the risk of spillage of drill fluid 106 which can spray outside of tarpoline 410 or away from pan 420 . Furthermore, tarpoline 410 is saturated with drilling fluid and must be properly disposed of.
FIG. 2 is a schematic view of a preferred embodiment of the present invention being used to recover column of drilling fluid or mud 104 in upper section of casing 30 . Recovery system 10 is installed on casing 20 and an opening in casing 20 is made through hole 185 . Recovery system 10 can be connected to recovery tank 120 and column of drilling fluid or mud 104 is drained through hole 185 . Column of drilling fluid or mud 104 is located in upper section of casing 30 and above the hole drilled through hole 185 . Pump 130 can be used to increase the rate of drainage of column of drilling fluid or mud 104 . Lower section of casing 40 can then be properly finished.
FIG. 3 is a perspective view of the recovery system 10 in FIG. 2 . Recovery system 10 can be comprised of body 150 and mounting rack 300 . FIG. 4 is a perspective view of body 150 of the recovery system 10 in FIG. 3 . FIG. 5 is a side view of body 150 of recovery system 10 in FIG. 3 .
Body 150 can be comprised of clamp 160 , tube 210 , and drill 260 .
Clamp 160 can be comprised of first portion 170 , second portion 180 , nipple 220 , and a plurality of fasteners 190 . Hole 185 can be included in second portion 180 . Clamp 160 and hole 185 preferably make a fluid tight seal with casing 20 after an opening in casing 20 is made through hole 185 . Clamp 160 can be sized based on the diameter of casing 20 to be drained. Nipple 220 can be attached to second portion 180 and nipple 220 can be threaded. Clamp 160 can also be removably connected to tube 210 (e.g., by a threaded connection with nipple 220 ) and a plurality of clamps 160 can be included to address different size casings 20 . Any conventionally available fastening method can be used in place of fasteners 190 . For example, first and second portions 170 , 180 can be pivotally connected on one side with a locking bracket on the other. However, a plurality of bolted fasteners 190 is preferred to accommodate variations in diameter of casing 20 .
Clamp 160 can also include liner 200 which assists in making a fluid tight seal against the surface of casing 20 . Liner 170 can be any conventionally available sealing material such as rubber, teflon, cork, paraffin, wax, plastic, metal, polymer, and other sealing materials. Liner 170 is shown covering first and second portions 170 , 180 , however, liner 170 can be placed only on second portion 180 or limited to the area around hole 185 , such as a washer or o-ring configuration.
Tube 210 can be connected to clamp 160 and drill 260 . Tube 210 can comprise T-connector 230 and coupling 250 . Valve 240 can be threadably connected to T-connector 230 . Valve 240 can include arm 241 and can be any conventionally available valve such as a ball valve, gate valve, or other commercially available valve. T-connector 230 can be threadably connected to nipple 220 . Coupling 250 can comprise a seal (e.g., O-rings 253 , 254 ) which sealingly and slidably connects shaft 280 to coupling 250 . Coupling 250 can also comprise a lubrication fitting 251 , which can be used to lubricate relative movement (longitudinal and rotational) between shaft 280 and tube 210 . Guard 312 can be attached to bracket 300 to protect against movement of shaft 280 and motor 270 .
FIG. 4A is a perspective view of the drill 260 used in recovery system 10 shown in FIG. 3 . Drill 260 can be comprised of motor 270 , shaft 280 and drill bit 290 (or hole saw). Motor 270 is preferably pneumatically powered to minimize the risk of explosion. Depth 293 of drill bit 290 (or hole saw) should be sized to at least accommodate the thickness of wall of casing 20 in which an opening is to be made through hole 185 . Diameter 294 of drill bit 290 (or hole saw) should be sized to accommodate flow of column 104 of drilling fluid or mud, but also pass through hole 185 . Drill bit 290 (or hole saw) can be any conventionally available drill bit and can also include a pilot bit to ease initial drilling of wall of casing 20 . It is to be understood that a hole saw is a special type of drill bit.
FIG. 7 is a perspective view of a portion of body 150 including clamp 160 , valve 240 , T-connector 230 , and coupling 250 . Valve 240 can include handle 241 and coupling 250 can include lubrication fitting 251 . FIG. 8 is a perspective view of shaft 280 including drill bit 290 , and base 281 . Drill bit 290 can include pilot drill bit 291 attached to the center of bit 290 . Drill bit 290 attaches to shaft 280 and shaft 280 attaches to base 281 . Base 281 attaches to motor 270 . FIG. 9 is an exploded view of shaft 280 and drill bit 290 . Drill bit 290 can include base 292 and base 292 attaches to shaft 280 .
FIGS. 10-11 illustrate insertion of drill bit 290 into body 150 through hole 185 . FIG. 10 is atop view of a portion of body 150 . Shaft 280 is partially inserted into body 150 through hole 185 . FIG. 11 is another perspective view of a portion of body 150 with drill shaft 280 partially inserted into body 150 through hole 185 .
FIGS. 12-13 illustrate longitudinal passage 186 through body 150 . FIG. 12 is a side view of a portion of body 150 showing hole 185 and longitudinal passage 186 . Longitudinal passage 186 can extend from hole 185 of section portion 180 through coupling 250 to end 256 . T-connector 230 provides an alternative path from passage 186 when valve 240 is in an open position. FIG. 13 is an end view of coupling 250 showing passage 186 . O-rings 253 , 254 can be used to make a fluid tight seal between shaft 280 and coupling 250 . Port 255 for lubrication fitting 251 can be used to allow lubrication to be injected between O-rings 253 , 254 and facilitate rotation/sliding between shaft 280 and O-rings 253 , 254 .
FIG. 6 is a perspective view of the mounting rack 300 for the recovery system 10 in FIG. 3 . Mounting rack 300 can be comprised of mounting bracket 310 , body 320 , drive shaft 340 , crank 350 , and base 330 for motor 270 . Mounting bracket 310 can have V-cuts 311 to attach to the wall of casing 20 . V-cuts 311 can be triangular or semicircular shaped. Motor 270 can be mounted on base 330 . Base 330 can be threadably connected to drive shaft 340 and track along length of body 320 . Turning crank 350 in the direction of arrow 351 can move base 330 in a longitudinal direction of arrow 352 . Turning crank 350 in the opposite direction can move base 330 in the opposite direction. Connectors 380 and arms 360 can be used with chain 360 (shown in FIG. 2 ) to mount rack 300 on casing 20 .
Before attaching recovery system 10 to casing 20 , body 150 is attached to mounting rack 300 . Clamp 160 was sized for the particular diameter of casing 20 . First portion 170 is removed from clamp 160 . Recovery system 10 is placed against casing 20 aligning hole 185 approximately at the location where casing 20 is ultimately to be cut. Mounting bracket 310 is placed against the wall of casing 20 . Second portion 180 of clamp 160 should also mount against the wall of casing 20 . Chain 360 is wrapped around casing 20 , arms 370 and connected to connectors 380 . First portion 170 of clamp 160 is attached to second portion 180 via fasteners 190 . Liner 200 will make a fluid tight seal with wall of casing 20 . Recovery system 10 can then be connected to pump 30 and recovery tank 120 through hoses 134 and 135 .
After being connected to casing 20 , motor 270 is started which rotates shaft 280 and drill bit 290 in longitudinal passage 186 of body 150 . As shown in FIG. 6 , crank 351 can be rotated in the direction of arrow 351 causing base 330 and drill 270 to move in the direction of arrow 352 . Shaft 280 and drill bit 290 , which are both located in longitudinal passage 186 , also move in the direction of arrow 352 . Drill bit 290 will pass through opening 185 and contact the wall of casing 20 . Pilot drill bit 291 will first contact wall of casing 20 making a pilot hole and steadying the drilling by drill bit 290 . Drill bit 290 will continue through the wall of casing 20 creating an opening the size of drill bit 290 . The portion of the wall of casing 20 which is cut out will be contained in the interior of drill bit 290 . Crank 350 is then turned in the opposite direction of arrow 351 causing drill bit 290 move in the opposite direction as arrow 352 and to recess into longitudinal passage 186 .
Column of drilling fluid or mud 104 will enter hole 185 and into longitudinal passage 186 of tube 210 . O-rings 253 , 254 sealing contact with shaft 280 will prevent drilling fluid or mud 104 from exiting from coupling 250 . Liner 200 prevents spillage of column of drilling fluid or mud 104 from between casing 20 and clamp 160 . Instead, flow of column of drilling fluid or mud 104 is directed from longitudinal passage 186 to valve 240 which can be opened via handle 241 . Flow will continue through hose 134 , pump 130 , hose 135 and into receiving tank 120 . Pump 130 can be used to greatly increase the flow of column of drilling fluid or mud 104 compared to gravity feed of the column.
After column of drilling fluid or mud is drained, recovery tool 10 is removed from casing 20 and casing 20 is cut using casing cutter 400 creating upper section of casing 30 . Upper section of casing 30 is then removed and lower section of casing 40 is prepared for further work related to oil and gas production.
While system 10 is shown as being constructed with most elements located below rig floor 17 where tanks 30 and 40 are conveniently out of the way, fluid recovery system 10 could also contain one or more tanks above the rig floor or positioned as is convenient for rig conditions.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and it will be appreciated by those skilled in the art, that various changes in the size, shape and materials, the use of mechanical equivalents, as well as in the details of the illustrated construction or combinations of features of the various elements may be made without departing from the spirit of the invention.
The following is a list of reference numerals:
LIST OF REFERENCE NUMERALS
(Reference No.)
(Description)
10
recovery system
20
casing
30
upper section of casing
40
lower section of casing
50
rig
60
rig floor
70
deck
80
deck
90
water surface
100
drilling fluid or mud
104
column of drilling fluid or mud
105
drilling fluid or mud
106
drilling fluid or mud
110
drilling fluid or mud
120
recovery tank
130
pump
134
hose
135
hose
150
body of recovery system
160
clamp
170
first portion of clamp
180
second portion of clamp
185
hole
186
longitudinal passage
190
fasteners
200
liner
210
tube
220
nipple
230
T-connector
240
valve
241
handle
250
coupling
251
lubrication fitting
253
O-ring
254
O-ring
255
port for lubrication fitting
256
end of coupling
260
drill
270
motor
280
shaft
281
base
282
end
283
keyway
290
drill bit (or hole saw)
291
pilot drill bit
292
base of drill bit
293
arrow
294
arrow
300
mounting rack of recovery system
310
mounting bracket
311
V-cut
312
guard
320
body
330
base for motor
340
drive shaft (which can be threaded)
350
crank
351
arrow
352
arrow
360
chain
370
arm
380
connector
400
casing cutter
410
tarpoline
420
pan
All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise.
It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention set forth in the appended claims. The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims. | A well bore fluid recovery system and method is disclosed for recovering a column of well bore fluid within a stand of casing before cutting the casing. The recovery system relates to a system for preventing fluids from being spilled when casing is being finished for a well bore. After being run the casing must be cut and finished at an appropriate level to install rig equipment such as blow out preventers along with other equipment. However, because of earlier operations, the entire length of casing is typically filled with drilling fluid. Depending on conditions, the length of casing which is to be cut and removed may therefore over a 100-foot (27.4 meter) column of drilling fluid therein. The drilling fluid in this section must be properly drained before the casing is cut and removed. |
BACKGROUND OF THE INVENTION
1. Industrial Field of the Invention
The present invention relates to a check valve apparatus for a fuel tank which is provided in a an end of pipe from a fuel supply spout to the fuel tank so that the check valve apparatus is opened when fuel flows toward the fuel tank at the time of fuel supply and closed when fuel flows reversely.
2. Description of the Prior Art
An example of conventional check valve apparatus for a fuel tank which functions in such a manner as to be open when fuel flows normally toward the tank at the time of fuel supply and closed when fuel flows reversely is disclosed in U.S. Pat. No. 4,128,111. This apparatus comprises independent component parts, such as a valve body, a valve plate, rotational axis pins, and the number of parts is large. Further, it is necessary to smash the tip of each of the rotational axis pin after the pin is assembled with the apparatus so that the pin will not dislodge.
The present invention has been accomplished to facilitate the assembling operation of such a check valve apparatus for a fuel tank and to reduce the number of its component parts. At the same time, there has been studied the structure of the check valve apparatus with which a valve plate will not be easily detached and the assembled apparatus will not accidentally come off from pipe.
SUMMARY OF THE INVENTION
A check valve apparatus for a fuel tank according to the present invention is characterized in that it comprises a valve plate made of synthetic resin, which is integral with rotating rod members at a position displaced from the circle center point of the valve plate, and a valve body made of synthetic resin including an annular valve seat which supports the outer periphery of the valve plate, the valve body including retainer projections which are provided on some portions of the outer peripheral side of the valve body, on the other side of which portions there are provided bearing sections corresponding to the rotating rod members of the valve plate.
The annular valve body in this case may be arranged in such a manner that the retainer projections are additionally formed at certain positions other than the two positions on the outer peripheral side of the valve body corresponding to those of the bearing sections. A positioning projection may be provided on the outer periphery of the valve body so as to be fitted in a cutout formed in the pipe. Projections may be further formed in the vicinity of the bearing sections in order to function as stoppers against the valve opening.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a check valve apparatus for a fuel tank according to the present invention;
FIG. 2 is a front view of the apparatus when assembled;
FIG. 3 is a cross-sectional view of the apparatus when installed in a pipe, taken along a line I--I in FIG. 2;
FIG. 4 is a back view of the apparatus when assembled, with a valve plate being open;
FIG. 5 is a front view of a valve body when the valve plate is removed;
FIG. 6 is a cross-sectional view of the valve body, taken along a line II--II in FIG. 5;
FIG. 7 is a schematic view of the entire structure of an automobile fuel tank;
FIG. 8 is a vertical cross-sectional view showing a condition of the valve body attached in the metal pipe in FIG. 3;
FIG. 9 is a vertical cross-sectional view showing that the valve body will not easily come off: and
FIG. 10 is a vertical cross-sectional view showing, on the contrary, that the valve body can be easily inserted into the pipe.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 7, a check valve apparatus 10 for a fuel tank used, for example, in an automobile, according to the present invention is provided within an end of a pipe 23 from a fuel supply spout 21 to the fuel tank 22. The check valve apparatus 10 is installed in such a manner that a valve body 3 extends substantially horizontally, to thereby be opened when fuel flows toward the tank 22 at the time of fuel supply and closed when fuel flows reversely. Referring to the right side of FIG. 1, a valve plate 1 is integral with rotating rod members 2 at a position displaced from the center line so that it maintains the closed state due to its own weight. Since the valve plate 1 in the closed state is affected by a pressure from the tank 22, mechanical strength of synthetic resin, surface ribs, an appropriate thickness and so forth are arranged to make the valve plate 1 rigid enough to stand the pressure.
Referring to the left side of FIG. 1, the valve body 3 made of synthetic resin and having an annular shape which supports the outer periphery of the valve plate 1 is provided with bearing sections 4 at positions corresponding to the valve plate rotating rod members 2. Each of the bearing sections 4 comprises hook-like upper and lower bearing projections 9 which are formed on the inner periphery of the valve body 3 so as to surround the associated valve plate rotating rod member 2. Also, on the inner periphery of the valve body 3, an inner peripheral rib 12 is provided on the rear side with respect to the center line of the rod members 2 and below the bearing sections 4, and an inner peripheral rib 13 is provided on the front side with respect to the center line of the rod members 2 and above the bearing sections 4, to thereby permit the valve plate 1 to rotate in only one direction. These inner peripheral ribs 12 and 13 also serve as a valve seat. In order to restrict further rotation of the valve plate 1 which has been opened and extended horizontally, stopper projections 8 are formed in the vicinity of the bearing sections 4 and on the rear side with respect to the center line of the rod members 2. When referring to FIGS. 2 to 6, structures of these component parts will be understood more clearly.
In order to assemble the valve plate 1 with the valve body 3 in the check valve apparatus for the fuel tank according to the present invention, the annular valve body 3 is merely pressed against its resilience radially inwardly (toward the center) from directions indicated by upper and lower arrows in FIG. 4 to expand the diameter to enlarge the distance between the left and right bearing sections 4 so that the rotating rod members 2 projecting from both sides of the valve plate 1 can be fitted in the bearing sections 4. When pressing the valve body 3 is stopped, the bearing sections 4 recover the original posture, and the rotating rod members 2 are fitted in them by snap action, thus completing the assembly. In this manner, the apparatus can be constituted only of the two members.
Retainer projections 5 are provided at three positions on the outer periphery of the valve body 3. Among these retainer projections 5, two upper ones are located at positions corresponding to the rotating rod members 2 which are formed at the position displaced from the Center line of the valve plate 1, while the remaining one is additionally provided at a lower position. A positioning projection 6 is formed at an upper location on the outer periphery of the valve body 3. As shown in FIG. 3, the apparatus of the invention can be properly set within the pipe 23 by merely fitting the positioning projection 6 in a cutout 7 formed in the pipe 23 during the setting operation of the apparatus. Another section of the outer periphery of the valve body 3 is formed as a flange 14 to be contacted with an end portion of the pipe 23 for the purpose of suitably positioning the apparatus and fluid-tightly connecting the peripheral portion of the valve body 3 with the end portion of the pipe 23.
When each of the upper retainer projections 5 is located at a position corresponding to the rotating rod member 2 of the valve plate 1 and formed on a portion of the outer peripheral side of the valve body 3 on the other side of which the bearing section 4 on an extension of the rotating rod member 2 is provided, the assembly is completed by merely pressing the retainer projections 5 into an annular recess 24 of the metal pipe 23.
FIG. 8 illustrates a condition in which the retainer projection 5 of the valve body 3 is closely fitted in the annular recess 24 of the pipe 23. When an external force F in a direction for withdrawing the valve body 3 is exerted on the valve body 3 in this condition due to a force of fluid flowing within the pipe 23, as shown in FIG. 9, a portion P of the valve body 3 with no retainer projection 5 or with no resistance is moved first. Consequently, the valve body 3 is inclined relative to the pipe 23, and strong engagement between a portion Q of the valve body 3 with the retainer projection 5 and the pipe 23 continues to be maintained. When the apparatus is inserted into the pipe 23, the length of the overlapped connection becomes as short as possible to facilitate the inserting operation. In order to insert the apparatus into a joint section of the pipe 23, the valve body 3 is inclined relative to the pipe 23, as shown in FIG. 10, so that the portion p of the valve body 3 with no retainer projection 5 will be closely fitted to the end portion of the pipe 23, and that the retainer projection 5 of the valve body 3 can be easily inserted into the annular recess 24 of the pipe 23. Similarly, when the apparatus is detached from the joint section of the pipe 23, the valve body 3 is inclined relative to the pipe 23, as shown in FIG. 10, so that the portion P of the valve body 3 with no retainer projection 5 will be closely fitted to the end portion of the pipe 23, and that the retainer projection 5 of the valve body 3 can be easily detached from the annular recess 24 of the pipe 23.
Moreover, since the retainer projections 5 are provided on the outer periphery of the bearing sections 4 of the valve body 3 which sustain the rotating rod members 2 projecting from both sides of the valve plate 1, the amount of radially inward deformation of the valve body 3 is limited by the valve plate rotating rod members 2 which serve as a strut, so that the valve body 3 can be prevented from coming off from the pipe 23 during operation.
As described heretofore, the check valve apparatus for the fuel tank according to the present invention is easy to assemble, and the number of component parts is lessened, thereby achieving the reduction of costs. The check valve apparatus is also arranged such that the valve plate will not be easily detached from the valve body, and that the valve body will not accidentally come off from the pipe. Besides, the check valve apparatus is improved in corrosion resistance, to thereby function favorably for a long period of time in such a manner as to be open when fuel flows normally toward the tank at the time of fuel supply and closed when fuel flows reversely. | A check valve apparatus for a fuel tank of an automobile or the like compries only two members, i.e., a valve plate made of synthetic resin which is integral with rotating rod members and a valve body made of synthetic resin and having an annular configuration which is integral with bearings or the valve plate. The check valve apparatus is simple in structure and easy to assemble. During operation after it has been assembled, it will not easily dislodge from a pipe, and when the operator intends to detach it from the pipe, it will be readily detached. |
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