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This application is a continuation of application Ser. No. 08/375,890, filed Jan. 20, 1995, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to heat stabilized chlorine-containing polyethylene- and polyether-based elastomer compositions having excellent heat resistance and chemical resistance, and more particularly to these chlorine-containing polyethylene- and polyether-based elastomer compositions which are heat stabilized with barium sulfate, and to high temperature and chemical resistant molded and extruded products including automotive hose and cable jacketing incorporating such elastomer compositions.
2. Description of the Prior Art
Chlorine-containing polyethylene- and-polyether-based elastomer compositions, including chlorinated polyethylene, chlorosulfonated polyethylene and epichlorohydrin elastomers, possess good mechanical properties, low compression set, good low temperature flexibility, and good dynamic fatigue resistance. These materials exhibit excellent aging, weathering, chemical and ozone resistance due to their saturated backbones, and the polarity contributed by the chlorine and ether components provide good oil swell resistance. This combination of properties makes these elastomers particularly well suited for applications including cable jacketing, automotive and industrial hose, molded goods and membranes.
Chlorine-containing polyethylene- and polyether-based elastomers require heat stabilization during curing or vulcanization to resist hydrochloric acid cleavage. Various heat stabilizers, including metal oxides such as magnesium oxide, lead compounds including dibasic lead-phthalate, lead-silicate and lead oxide, sulfur-containing organotin compounds, as well as epoxidized soybean oils and cycloaliphatic epoxy resins have been used for this purpose. Barium carbonate has been used to stabilize epichlorohydrin elastomers, but the resulting compounds exhibit inferior mechanical properties. Lead compounds typically provide the best aging resistance and until recently, were the most commonly used compounds for this purpose. Mixed metal salts such as barium-cadmium, barium-zinc, and calcium-zinc salts are also known heat stabilizers.
Many of the heat stabilizers commonly used present various problems due to their toxicity. Section 313 of the Emergency Planning and Community Right-to-Know Act of 1986 (42 U.S.C. 11023, "EPCRA"), for example, requires certain facilities manufacturing, processing or otherwise using listed toxic chemicals to report their environmental releases of such chemicals annually. Section 6607 of the Pollution Prevention Act (42 U.S.C. 13106, "PPA") requires facilities to report pollution prevention and recycling data for these chemicals, beginning in the 1991 reporting year. More than 300 chemicals and 20 chemical categories are listed in Section 313 of EPCRA. Toxicity concerns and increased reporting costs have resulted in a decrease in the use of lead, barium, and cadmium which leave calcium and magnesium as the most commonly used heat stabilizers. These materials however, are known to be moisture sensitive and cause water absorption and are therefore unsatisfactory.
Consequently, a need exists for improved heat stabilized chlorine-containing polyethylene- and polyether-based elastomer compositions which exhibit excellent heat resistance and chemical resistance, and which address toxicity concerns.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide improved heat-stabilized chlorine-containing polyethylene- or polyether-based elastomer compositions which substantially avoid these toxicity concerns.
It is a further object of the present invention to provide an improved heat resistant, chemical resistant automotive hose incorporating as at least one elastomeric member, an improved heat-stabilized chlorine-containing polyethylene- or polyether-based elastomer composition.
To achieve the foregoing and other objects and in accordance with a purpose of the present invention as embodied and broadly described herein, an elastomeric composition for incorporation in an article subject to high temperature or chemical exposure is provided, comprising the reaction product of 100 parts of a chlorine-containing polyethylene- or polyether-based elastomer and from about 1 to about 25 parts per hundred weight of said elastomer (phr), of a barium sulfate stabilizer which serves as the heat stabilizer for the elastomer.
In another embodiment, the present invention provides an improved high temperature, chemical resistant hose, comprising an elastomeric inner tube, a reinforcement layer telescoped about and preferably adhered to the inner tube, and optionally, a cover telescoped about and preferably adhered to the reinforcement layer. The cover may comprise either a fabric or elastomeric material, or a first elastomeric layer covered by a fabric layer. According to this embodiment of the present invention, at least one elastomeric member of the hose, i.e., the inner tube or the cover portion, is formed of an elastomer comprising a chlorine-containing polyethylene- or polyether-based elastomer which has been stabilized with barium sulfate. The inner tube may be of a multiple-layer construction, wherein the layers are not made of the same material. In the preferred embodiment however, the entire inner tube comprises the chlorine-containing polyethylene- or polyether-based elastomer heat stabilized with barium sulfate of the present invention.
The improved barium sulfate heat stabilized chlorine-containing polyethylene- or polyether-based elastomer composition of the present invention may contain various compounding agents known in the art such as fillers, reinforcing agents, plasticizers, softeners, antioxidants and process aids, in amounts generally known in the art.
BRIEF DESCRIPTION OF THE DRAWING
The accompanying drawings which are incorporated in and form a part of the specification, illustrate preferred embodiments of the invention, and together with the description, serve to explain the principles of the invention.
FIG. 1 is a perspective view, with parts in section, of a transmission oil cooler hose constructed in accordance with the present invention.
FIG. 2 is a perspective view, with parts in section, of a power steering hose constructed in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a transmission oil cooler hose 10 constructed according to one embodiment of the present invention is shown. The hose 10 comprises an elastomeric innertube 12, a reinforcement member 14 telescoped over and preferably adhered to the inner tube 12, and an elastomeric outer cover 16 telescoped over and preferably adhered to the reinforcement member 14. The reinforcement member 14 is formed of a suitable reinforcement material which may include organic or inorganic fibers or brass-plated steel wires. The reinforcement material is preferably an organic fiber material, such as nylon, polyester, aramid, cotton or rayon. The reinforcement construction may be of any suitable type such as braid, spiral, knit or wrapped, but in the embodiment shown, is of a braid construction.
The inner tube 12 may consist of multiple elastomeric layers which may or may not be of the same composition, however in the preferred embodiment shown, the entire inner tube is made of the containing chlorine-containing polyethylene- or polyether-based elastomer composition of the present invention.
The elastomeric outer cover 16 is made of suitable materials designed to withstand the exterior environment encountered. In the preferred embodiment shown, the outer cover 16 is made of the containing chlorine-containing polyethylene- or polyether-based elastomer composition of the present invention.
Referring to FIG. 2, a power steering hose 20 constructed according to one embodiment of the present invention is shown. The hose 20 comprises an elastomeric inner tube 22, a reinforcement member 24 telescoped over and preferably adhered to the inner tube 22, and an elastomeric outer cover 26 telescoped over and preferably adhered to the reinforcement member 24. The reinforcement member 24 comprises one or more alternating reinforcement layers 21, 23 and one or more insulating elastomer layers 25. The reinforcement layers 21, 23 are formed of a suitable reinforcement material which may include organic fibers or brass-plated steel wires, and may be of any suitable construction and material such as those described for FIG. 1 but in the embodiment shown, are of a braid construction.
The inner tube 22 may consist of multiple elastomeric layers which may or may not be of the same composition, however in the preferred embodiment shown, the entire inner tube comprises the barium sulfate heat stabilized chlorine-containing polyethylene- or polyether-based elastomer composition of the present invention.
The elastomeric outer cover 26 and insulating elastomer layer 25 or layers are made of suitable materials designed to withstand the exterior environment encountered. In the preferred embodiment shown, the outer cover 26 and the insulating elastomer layer 25 are made of the barium sulfate heat stabilized chlorine-containing polyethylene- or polyether-based elastomer compositions of the present invention.
While the present invention is illustrated with reference to the embodiments shown, it should be understood that the present invention is not to be limited to these particular embodiments or forms as illustrated, but rather is applicable to any elastomeric construction within the scope of the claims as defined below.
The chlorine-containing polyethylene- or polyether-based elastomers useful for the present invention include but are not limited to chlorinated polyethylene elastomer, chlorosulfonated polyethylene elastomer, chlorinated ethylene/propylene elastomer, chlorinated ethylene/propylene/diene elastomer, chlorinated ethylene/1-butene rubber, chlorinated ethylene/4-methylpentene elastomer, polyepichlorohydrin elastomer, epichlorohydrin/ethylene oxide copolymer elastomer and epichlorohydrin/allyl glycidyl ether copolymers and terpolymers. In a preferred embodiment, at least one elastomeric member of a hose comprises a chlorine-containing polyethylene-based elastomer composition which has been heat stabilized with barium sulfate, and in the most preferred embodiment, at least one elastomeric member of a hose comprises chlorinated polyethylene which has been heat stabilized with barium sulfate.
Barium sulfate is commonly used as an inert filler in elastomeric compositions, comprising from about 60 to about 500 phr of such compositions. Barium sulfate used as an inert filler is especially common where non-discoloration of the final product is desired, or where high specific gravity or sound deadening is required. Barium sulfate has been used as a filler for natural rubbers, synthetic rubbers, latexes, and polyurethane foams.
The U.S. Environmental Protection Agency deleted barium sulfate from its list of toxic chemicals for which reporting is required under EPCRA, and therefore also from the chemicals listed under PPA. Among other information, PPA requires reporting of the quantity of listed chemicals entering any waste stream or otherwise released into the environment, prior to disposal.
It has now been surprisingly found that barium sulfate functions as a heat stabilizer in the curing or vulcanization of chlorine-containing polyethylene- and polyether-based elastomers, when used in amounts suitable for heat stabilization, i.e., from about 1 to about 25 phr. Chlorine-containing polyethylene- and polyether-based elastomers which have been stabilized with barium sulfate exhibit excellent physical properties, substantially equivalent in all relevant respects to such elastomers which have been stabilized with lead oxide. Heat stabilizers are generally added to chlorine-containing elastomers in amounts of from about 1 to about 30 phr. The barium sulfate used to heat stabilize the chlorine-containing polyethylene- or polyether-based elastomers in the present invention is used in amounts of from about 1 to about 25 parts per hundred weight of the elastomer (phr). It is preferably used in amounts of from about 8 to about 18 phr, and in the most preferred embodiment, barium sulfate is used in amounts of from about 10 to about 15 phr. Thus when used as a heat stabilizer for chlorine-containing polyethylene- and polyether-based elastomers, barium sulfate is used in far lesser amounts than when used as a filler for such elastomers.
The improved heat stabilized chlorine-containing polyethylene- or polyether-based elastomer composition of the present invention may contain various compounding agents known in the art such as fillers, reinforcing agents, plasticizers, softeners, antioxidants and process aids, in amounts generally known in the art. For example, fillers such as carbon black, hydrated silicates, clays and talcs may be used in amounts of from about 5 to about 250 phr; reinforcing agents such as phenolic and petroleum resins, may be used in amounts of from about 5 to about 200 phr; plasticizers such as phthalic acid derivatives and adipic acid derivatives may be used in amounts of from about 1 to about 25 phr; antioxidants may be used in amounts of from about 0.1 to about 10 phr; and cross-linking agents may be used in amounts of from about 0.1 to about 10 phr.
The chlorine-containing polyethylene- or polyether-based elastomers heat stabilized with barium sulfate useful in the present invention may be prepared by any conventional procedure such as for example, by mixing the ingredients in an internal mixer or on a mill.
The following examples are submitted for the purpose of further illustrating the nature of the present invention and are not intended as a limitation on the scope thereof. Parts and percentages referred to in the examples and throughout the specification are by weight unless otherwise indicated.
For the following examples:
______________________________________Trade Name and Material Supplier______________________________________Tyrin CM 0836 - Chlorinated Polyethylene, Dow Chemical Co.36% Chlorine, Mooney viscosity 100Tyrin CM 0136 - Chlorinated Polyethylene, Dow Chemical Co.36% Chlorine, Mooney viscosity 80N774 - Carbon Black J. M. Huber Corp.Barytes - Barium Sulfate Harcros Chemicals, Inc.Akrosperse 243 - Basic silicate white lead- Akrochem Co.chlorinated polyethylene dispersionHubercarb Q325 - Calcium Carbonate J. M. Huber Corp.Zeolex 80 - Synthetic Sodium aluminum J. M. Huber Corp.silicatePlasthall TOTM - Trioctyl trimellitate C. P. HallPlasthall DAP - Diallyl phthalate C. P. HallMaglite D - Magnesium Oxide C. P. HallAgeRite Resin D - Polymerized 1,2-dihydro- R. T. Vanderbilt2,2,4-trimethyl quinolineTAIC - triallyl isocyanurate MitsubishiTrigonox 17-40 - 40% n-butyl 4,4-bis(t-butyl Akzo Chemicals, Inc.peroxy) valerate on calcium carbonate fillerVul-Cup 40KE -α-α-bis(t-butyl peroxy) Hercules, Inc.diisopropyl benzene on Burgess KE clay______________________________________
Table 1 describes formulas for several compositions made according to the present invention. Tables 2, 3, and 4 describe properties of plate samples of the compositions described in Table 1. These properties were measured according to the following test protocols: General Physical Test Requirements by ASTM Practice D3183, Tension Test by ASTM D412, Heat Aging by ASTM D572, Deterioration in Air Oven by ASTM D573, and Effect of Liquid Immersion by ASTM D471.
TABLE 1__________________________________________________________________________Formulas Example Example Example Example Example ExampleMaterial 1, phr 2, phr 3, phr 4, phr 5, phr 6, phr__________________________________________________________________________Tyrin CM 100 100 100 100 100 1000836N774 54 54 54 54 54 54Barytes 12 18 16 14 10 8Hubercarb 20 20 20 20 20 20Q325Zeolex 80 43.25 43.25 43.25 43.25 43.25 43.25Plasthall 35 35 35 35 35 35TOTMPlasthall 13 13 13 13 13 13DAPMaglite D 9.75 9.75 9.75 9.75 9.75 9.75AgeRite 0.5 0.5 0.5 0.5 0.5 0.5Resin DTAlC 2 2 2 2 2 2Trigonox 5 5 5 5 5 517-40Vul-Cup 3.5 3.5 3.5 3.5 3.5 3.540KE__________________________________________________________________________
For all examples and comparative examples, compounding was accomplished in the following manner. Processing was carried out in a Banbury mixer having an inner volume of 16,500 cubic centimeters; kneading was carried out at approximately 30 rpm. The batches were processed as two-pass mixes. In the first pass, all ingredients except the Trigonox 17-40 and Vul-Cup 40KE were added to the Banbury mixer and mixed to a temperature sufficiently above ambient so as to affect dispersion, and then dropped. In the second pass one half of the mixed batch was added to the Banbury mixer, followed by the Trigonox 17-40 and the Vul-Cup 40KE, then the second half was added. The batches were remilled to about 104° C. and then dropped.
Physical tests were conducted for all molded compounds after molding and again after heat aging at 150° C. for 168 hours. Tables 3 and 4 include heat aged results for samples aged in dry air, and in Dextron IIE transmission fluid, respectively.
TABLE 2__________________________________________________________________________Properties of Unaged SamplesExample Example Example Example Example Example1 2 3 4 5 6__________________________________________________________________________% Eb 209.6 235.9 226.9 225.1 234.5 233.5M100(psi) 1097 1103 1100 1133 1109 1120% Compres- 28.6 29.1 27.1 27.5 27.2 30.2sion SetSpecific 1.485 1.515 1.511 1.493 1.481 1.473Gravity__________________________________________________________________________
TABLE 3__________________________________________________________________________Properties of Samples Aged in Dry Air,168 hours at 150° C.Example Example Example Example Example Example1 2 3 4 5 6__________________________________________________________________________Tensile at 2225 2146 2208 2200 2189 2005break% Tensile 116 106 111 108 106 96retained% Eb 130.9 125.6 136.8 130.9 135.3 113.3% Eb 62 53 60 58 58 49retained__________________________________________________________________________
The data of Tables 2 and 3 indicate that samples heat stabilized with barium sulfate exhibit good material properties when unaged as well as when aged. Data for Example 2 and Example 6 indicate that at barium sulfate levels of 8 phr and 18 phr, respectively, elongation retention values on aging begin to deteriorate. The preferred range of barium sulfate for these examples is thus between 8 and 18 phr. Optimal elongation at break is obtained at barium sulfate levels of 12 phr, as shown in Example 1.
TABLE 4__________________________________________________________________________Properties of Samples Aged in Dextron IIE,168 hours at 150° C. Example Example Example Example Example Example 1 2 3 4 5 6__________________________________________________________________________Tensile at 1541 1451 1638 1668 1655 1651break (psi)% Tensile 81 71 82 82 80 79retained% Eb 98.91 97.55 105.6 106.3 103.1 106.1% Eb retained 47 41 47 47 44 45Volume 12.9 12.6 13.0 12.8 12.6 12.5Change %__________________________________________________________________________
The data in Table 4 indicate that samples heat stabilized with barium sulfate in levels of from 8 to 18 phr perform acceptably upon aging in Dextron IIE transmission fluid.
Table 5 describes formulas for two compositions which were manufactured and formed into the elastomeric components of a transmission oil cooler hose, as described in FIG. 1. Formula A represents one embodiment of the present invention. Comparative Formula B represents a substantially similar formula incorporating lead oxide as a heat stabilizer in place of barium sulfate. Tables 6, 7 and 8 describe properties of samples of the elastomeric portions of the hoses prepared and analyzed as described in ASTM D380.
TABLE 5______________________________________FormulasMaterial Formula A, phr Comparative Formula B: phr______________________________________Tyrin CM 0536 100 0Tyrin CM 0136 0 100N774 54 54Barytes 12 0Akrosperse 243 0 11.9Hubercarb Q325 20 20Zeolex 80 43.25 43.25Plasthall TOTM 35 35Plasthall DAP 13 13Maglite DE 9.75 9.75AgeRite Resin D 0.5 0.5TAlC 2 2Trigonox 17-40 5 5Vul-Cup 40KE 3.5 3.5______________________________________
TABLE 6______________________________________Properties of Unaged Samples Comparative Formula A sample Formula B sample______________________________________Tensile at break (psi) 1970 2134% Eb 244 221M100 (psi) 1025 1241M200 (psi) 1716 2050Durometer 84 82Compression set (cure 20.3 20.3time 60 mins, at 165° C.)______________________________________
TABLE 7______________________________________Properties of Samples Aged in Dry Air,168 hours at 150° C. Comparative Formula A sample Formula B sample______________________________________Tensile at break (psi) 2077 2082% Tensile retained 105 98% Eb 120.1 112.6% Eb retained 49 51Durometer 93 94Durometer change 9 12______________________________________
TABLE 8______________________________________Properties of Samples Aged in Dextron IIE70 hours at 168° C. Comparative Formula A sample Formulation B sample______________________________________Tensile at break (psi) 1635 1764% Tensile at break 83 83retained% Eb 129.3 114.7% Eb retained 53 52M100 1239 1502% M100 retained 121 121Durometer 70 70Durometer change -14 -12Volume Change, % 13.9 15.4______________________________________
The data in Tables 6, 7 and 8 indicate that hose samples incorporating chlorinated polyethylene elastomer prepared with barium sulfate as the heat stabilizer perform substantially the same in all relevant respects as such samples incorporating chlorinated polyethylene elastomer prepared with lead oxide as the heat stabilizer.
The improvement of the present invention is the incorporation of barium sulfate, in amounts of from about 1 to about 25 phr, as a heat stabilizer for chlorine-containing polyethylene- and polyether-based elastomers. The invention includes an improved heat and chemical resistant hose, wherein at least one elastomeric member of the hose comprises a chlorine-containing polyethylene- or polyether-based elastomer heat stabilized with barium sulfate. In a preferred embodiment, at least one elastomeric member of the hose comprises a chlorinated polyethylene elastomer heat stabilized with barium sulfate.
Although the present invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by one skilled in the art without departing from the spirit or scope of the present invention except as it may be limited by the claims. The invention illustratively disclosed herein may be suitably practiced in the absence of any element which is not specifically disclosed herein. | Chlorine-containing polyethylene- and polyether-based elastomer compositions having excellent heat resistance and chemical resistance, which are heat stabilized with from about 1 to about 25 parts per hundred weight of the elastomer of barium sulfate, and high temperature and chemical resistant molded and extruded products including automotive hose and cable jacketing incorporating such elastomer compositions. |
TECHNICAL FIELD
This application relates generally to motor controls and more particularly relates to electrical current protection for windshield wiper motors.
BACKGROUND OF THE INVENTION
DC motors have found wide use in automotive applications. It is not uncommon to find DC motors used in the window lift mechanism, seat lift mechanism, sun roof controls, door locks, trunk pull-down assemblies etc. In at least some of these applications, electrical current protection must be provided to the DC motor in order to prevent excessive current draw through the motor or motor control circuit during the motor stall or highly loaded conditions. If some type of current protection is not provided in the DC motor circuit, it is possible that under the stall or highly loaded conditions, the motor will draw sufficient current to destroy either itself, portions of the motor control circuit, or both.
Another common use for DC motors in automotive applications is in windshield wiper assemblies where it is common to employ a DC motor for driving the windshield wipers of the vehicle. Because windshield wiper systems must typically operate in a number of modes (such as park mode, retract mode, high speed, low speed, etc.), the control systems for windshield wiper DC motors tend to be some of the most complex motor control systems found in automotive applications. The systems often utilizes a kinematic linkage between the motor drive shaft and the wiper arm drive system along with electrical sensing circuits located on the wiper drive system to provide feedback information relating to the position of the wiper blades on the windshield. These sensing circuits typically employ switches which can be vulnerable to excessive current conditions especially when an over current condition exist when the wiper blade is restricted in the vicinity of the park position on the windshield. This "over current near park" condition commonly occurs when there is snow or ice buildup along the outlying portion of the windshield wiper stroke. When this snow block condition occurs, the wiper control system tends to cycle the switches responsible for sensing the position of the wiper arm. This cycling causes the switches to move along leading edges of the switch cam which in turn tends to induce arcing between the switch contacts resulting in excessive heat buildup which eventually destroys the switch contacts or melts the plastic which commonly forms the substrate which carries many of the electrical switch components and other drive components found in windshield wiper systems.
Accordingly, it is an object of this invention to set forth a windshield wiper control system consisting of a DC motor and a control circuit wherein the DC motor is prohibited from drawing excessively high currents which would otherwise destroy the DC motor or its control circuitry.
It is also an object of this invention to set forth a over current protection circuit for a windshield wiper system of a vehicle wherein only the park mode of operation is affected by the over current circuit and the remaining wiping modes (high speed, low speed, and intermittent) are not affected by the over current protection circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a vehicle windshield and the windshield wiper path traversed thereon.
FIG. 2 is a functional/electrical schematic diagram of the control system of the present invention.
FIG. 3 is a schematic depiction of the park plate of the present invention.
FIG. 4A is a characteristic curve for a typical positive temperature coefficient (PTC) device.
FIG. 4B is a non-windshield wiper motor protection circuit using a PTC device.
FIG. 4C is a signal diagram indicating five modes of operation of the circuit of FIG. 4B.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now referring to FIG. 1, the control system of the present invention is designed to control the movement of wiper blades 10, 12 as they move across the surface of windshield 14. When wipers 10, 12 move across surface 14 in a snowstorm or the like, it is not uncommon for such systems to encounter a condition of ice or snow buildup at the out-wipe 16 or in-wipe 18 zones of windshield 14. When wipers 10, 12 encounter such a build up in the in-wipe zone 18, blades 10, 12 are restricted from parking which in turn creates the condition whereby the various electrical components of the motor control circuit are exposed to exceptionally high currents which can ultimately destroy components of the motor control circuit.
The motor control circuit of the present invention and its various components will now be examined in detail.
Now referring to FIGS. 1 and 2, wiper control system 19 includes motor casing 20, wiper motor controller 21 and operator selector switch 25. Packaged within motor casing 20 are the DC motor's armature and brushes 22 which are mechanically and electrically linked 26 to motor park plate and gear assembly 24. Motor park plate and gear assembly 24 interfaces with one or more switching elements 30, 30' which function to convey electrical signals to wiper motor controller 21 by way of electrical wires 34. These signals are indicative of the position of wipers 10, 12 as they travel across windshield 14. Wiper motor controller 21 accepts various signals transmitted along cable 32 from operator selector switch 25 and uses those signals in conjunction with the feedback signals present on line 34 to control DC motor 22 by way of output control lines 36.
Now referring to FIGS. 1-3, when wiper control system 19 encounters a condition whereby wiper arms 10, 12 are restricted from entering end-wipe zones 18 (this condition is typical when the vehicle is being operated in snow or ice conditions), switch elements 30, 30' (see FIG. 3) will cycle between the pack mode and non-park mode and this cycling will give rise to arcing in a localized area of motor park plate and gear assembly 24 which contacts the particular switch element 30, 30'. These high localized currents will eventually cause electrical failure of switch elements 30, 30' and may ultimately melt the park plate gear assembly 24 which is typically comprised of plastic, nylon or the like. In some designs, this problem is particularly acute when wiper blades 10, 12 are restricted generally between the angular positions greater than 4° from park and less than 10° from park. This angular range is represented by reference numeral 38 for wiper 12 and represented in FIG. 1 by reference numeral 40 for wiper 10.
Motor park plate and gear assembly 24 (FIG. 3) rotates in synchronism with motor 22. Switch elements 30, 30' are stationary within motor casing 20 and ride along tracks defined in a surface of motor park plate and gear assembly 24. During normal operation (i.e. no snow block condition), contacts 30, 30' will be aligned close to the vertical axis 42 when motor 22 is in the park state. In a severe snow block scenario (wherein wipers 10, 12 are restricted within their respectively associated angular ranges 40, 38) switch element 30 would be located on the right-most edge 43 of the COAST TO PARK region 44 of motor park plate and gear assembly 24 (shown in FIG. 3). With switch element 30 within COAST TO PARK region 44 motor 22 is powered down. When switch element 30 is located outside 45 of COAST TO PARK region 44, motor 22 is powered up. Under severe snow restriction (i.e. wiper arms 10, 12 located within their respective angular range 40, 38), switch element 30 oscillates back and forth at the leading edge 46 of COAST TO PARK region 44 making an objectionable "growling" noise which is audible from within the vehicle. This growling noise indicates that the motor is cycling between a powered up mode and a powered down mode. When this occurs, arcing takes place between switch element 30 and leading edge 43 of COAST TO PARK region 44. This arcing eventually results in melting a hole in the motor park plate and gear assembly 24 and destroying switch element 30.
The above scenario occurs under severe snow block scenario where the build up of snow between the vehicle cowl and wipers 10, 12 will not allow system 19 to place wipers 10, 12 in the proper park position.
In order to limit the above-mentioned undesirable growling or prevent the destruction of control system 19 due to excessive current flow, positive temperature coefficient (PTC) device 28 is placed in series with park signal line 48. Placing PTC device 28 in park signal line 48 places it in series with motor 22. Thus, during park mode, whenever motor 22 stalls or electrically arc under a snow block condition, all of the current flowing through motor 22 also flows through PTC device 28. In non-park mode PTC device 28 is not in series with motor 22 and accordingly, cannot influence the function of motor 22. The characteristic curves associated with a particular polymeric PTC device manufactured by Therm-O-Disc, Inc., 1320 S. Main Street, Mansfield, Ohio 44907-0538, telephone (419) 525-8500 is found on FIG. 4A. The graph of FIG. 4A readily demonstrates that the internal resistance of PTC device 28 can change four or more orders of magnitude as a function of the temperature of the PTC device. The PTC device selected should have a very low resistance when operating in the normal current ranges associated with motor 22. However, when motor 22 encounters a stall condition, an arc condition, or excessive loads, its current draw increases dramatically thereby causing the PTC device 28 to heat up due to internal I 2 R ohmic losses. Once PTC device heats up (beyond critical point 50) its internal resistance escalates dramatically thereby "choking off" current to motor 22. In order to reset a PTC device current through, the device must be discontinued.
FIG. 4B shows a typical installation of a PTC device when used in conjunction with a motor. FIG. 4C shows various currents associated with the various modes of operation of the circuit of FIG. 4B.
An important aspect of the wiper control system of the present invention is that the PTC device is only present within the motor circuit if the operator has placed the selector switch 25 in the off (or park) position. Thus, when the system is placed in the "on" position, the PTC device is not electrically connected to motor 22 and will not affect the critical operation of wiper motor 22. Thus, the system integrity is preserved (i.e. wipers 10, 12 will still function) even if PTC device 28 should fail inasmuch as it does not conduct motor 22 current during the normal run mode.
It is recognized that those skilled in the art may make various modifications or additions to the preferred embodiments chosen here to illustrate the present invention, without departing from the spirit of the present invention. Accordingly, it is to be understood that the protection sought to be afforded hereby should be deemed to extend to the subject matter claimed and in all equivalents thereof fairly within the scope of this invention. | A wiper control system including a current sensing device is used in conjunction with a park position switch to limit the current drawn by windshield wiper motor whenever the system experiences restrictions in a park mode. The arrangement of components is effective for preventing damage to the motor and motor control system caused by excessive current draw whenever the motor stalls, arcs, or experiences excessive loads. However, the current sensing portion of the circuit is essentially disabled when the motor is in its normal operating mode thus preserving the fail safe operation of the wipers. |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of our earlier filed U.S. application Ser. No. 508,213 filed June 27, 1983, now U.S. Pat. No. 4,536,392.
FIELD OF INVENTION
This invention relates to the control of bleeding in mammals. More particularly this invention relates to the therapeutic treatment of Factor VIII:C deficient (hemophilic) patients by means of a Factor VIII:C bypass technique using a synergistic mixture of phospholipids with Factor Xa, and the rapid control of bleeding in normal patients.
BACKGROUND OF INVENTION
Classic Hemophilia A is a sex-linked recessive inherited disorder of the blood where the activity of a specific coagulation factor (protein), required for the cascade or chain process for blood coagulation, is either reduced or absent, which has been identified in only three mammalian species, namely man, dogs and horses. Hemophilia afflicts about 1 in 10,000 of the human male population. This produces a severe bleeding disorder and constitutes the most frequently clinically encountered congential coagulation disorder. Since about 1965 the prognosis of affected individuals has considerably improved due to the availability of specific clotting factor replacement products derived from the blood of normal donors which can be transfused. These products contain the most usually absent factor, Factor VIII in a concentrated form. Unfortunately, however, approximately 10% of all treated hemophiliacs develop antibodies to the transfused Factor VIII:C and become treatable by this means.
Further, a very large number of blood donors are required to produce commercial quantities of the replacement factors, with the consequent high risk of infection with virus diseases such as hepatitis and Acquired Immune Deficiency Syndrome. It is one aim of the present invention to provide a method for the treatment and management of such antibody sensitized hemophiliacs. It is another aim to provide an alternative to conventional Factor VIII:C replacement therapy using material which can be produced from a very small number of carefully screened donors to substantially reduce the risk of viral infection. It is yet another aim of the invention to provide a method for the rapid control of bleeding in normal mammals, which could be used in emergency situations such as battlefield casualties, trauma both inside and outside an operating room and other comparable situations.
DISCUSSION OF THE PRIOR ART
Heretofore hemophiliacs with antibodies to F. VIII:C have been managed by various therapies none of which are satisfactory. The use of immunosuppressive therapy is not entirely satisfactory and is associated with increased morbidity. The use of Factor VIII:C derived from other species, i.e. procine or bovine, has been shown to be an effective replacement but may be associated with major side effects due to the development of heterologous antibodies. Recently considerable interest has been shown in using prothrombin complex concentrates (PCC). As explained in more detail hereinafter, blood coagulation proceeds by a series or cascade of activation steps where circulating inactive clotting factors (zymogens) are converted to proteolytic enzymes. The final product of the cascade is thrombin (IIa) which converts the sol protein, fibrinogen, to its gel form, fibrin. Recent work has demonstrated that Factor VIII:C is not a proteolytic enzyme but a potent co-factor of the activation step whereby Factor IXa activates Factor X to Xa. In classic Hemophilia A, this co-factor activity is reduced or missing so that insignificant activation of Factor X takes place despite all other clotting factors being present at normal levels. As noted above, transfusion of Factor VIII:C concentrates can correct this abnormality and similar concentrates have been developed for the congenital deficiency of Factor IX. These concentrates differ from those of Factor VIII:C in containing significant quantities of other clotting factors namely X, VII and II (prothrombin). Moreover, it is the rule that all concentrates contain trace contaminents of the activated products of these clotting factors, namely IXa, Xa, VIIa and IIa (thrombin). It will be noted that, with the exception of Factor IX, the remaining three clotting factors are placed in the cascade below the critically important Factor VIII:C-dependent step. It has been postulated, that these concentrates, by providing preformed activated products, may achieve Factor VIII:C bypassing activity (FEBA) in hemophiliacs where Factor VIII:C replacement is precluded by the development of antibodies to this clotting factor. Initial anecdotal clinical reports were promising but by no means unanimous. This lack of unanimity related to the uncertainty as to which, if any, of the component clotting factors were the most critical. The products used are of two types. The first are known as "unactivated" PCC and are products that have been developed specifically to replace deficiencies of the clotting factors that they contain. In such patients, it is considered undesirable to infuse pre-activated clotting factor because of concern for thromboembolic side effects. Therefore, attempts are made, in the fractionation process, to minimize the activated clotting factor content although all products contain some. As it was the activated clotting factor content that was considered to be the putative agent(s) in the treatment of hemophiliacs with inhibitors, some manufacturers have deliberately activated the PCC preparations for this purpose. These are known as "activated" PCC. Recent clinical trials have confirmed the benefit of the use of non-activated PCC as compared with placebo but the response was less than optimal in comparison to that which would be expected from conventional Factor VIII:C replacement in hemophiliacs without inhibitors. A similar study compared treatment with an unactivated PCC with an activated PCC prepared by the same manufacturer. There appeared to be a marginal benefit in favour of the activated preparation. Despite this, the response remained suboptimal and the absence of any clear indication as to the specific constituent of the preparation responsible for the effect seen, it is impossible to ensure inter-bath reproducibility of individual production lots of apparently the same product. As a result, there is still not universal agreement as to the validity of this approach.
In "Blood", v. 59, p. 401-407, Feb. 1982, Giles et al demonstrated that the in vivo thrombogenicity of prothrombin complex concentrates was highly correlated with their individual content of coagulant active phospholipid. However, this component alone was nonthrombogenic but required the presence of Factor Xa. At high dose, the latter was thrombogenic alone but its potency was drastically increased in the presence of small amounts of coagulant-active phospholipid. It was suggested that the combination of these two components accounted for the thrombogenicity associated with the use of prothrombin complex concentrates and evidence was presented that this thrombogenic effect could be mimicked by a combination of highly purified Factor Xa and phosphatidylcholine-phosphatidylserine (PCPS) lipid vesicles. This confirmed the finding of Barton et al in the Journal of Lipid Research V.11, p. 87, 1970, who used less well-defined protein/lipid components.
SUMMARY OF INVENTION
As is known from the prior art, the presence of Factor Xa alone bypasses the requirement for Factor VIII:C. Although this is the case in vitro, in vivo the presence of a number of inhibitory processes complicate its use in achieving Factor VIII:C bypassing activity. Combining this factor with coagulant-active phospholipid in the form of PCPS vesicles exerts an apparent synergistic activity in vivo presumably by mimicking the normal interactions between Factor Xa and platelet phospholipid. It has been demonstrated that the cose of each component administered is critical in that a minimum dose of Factor Xa/kg body weight is required and that the dose of phospholipid must be limited to avoid unacceptable toxicity (thrombogenicity).
It has now also been found that administration of a synergistic mixture of PCPS and mammalian Factor Xa to a normal, as opposed to hemophilic subject, exerts a powerful influence upon the normal blood coagulation process. The normal interaction between Factor Xa and platelet phospholipid is accelerated and bleeding time is significantly reduced.
Thus by one aspect of this invention there is provided a pharmaceutical composition for the treatment of hemophilia in mammals comprising a synergistic mixture of phospholipid vesicles and mammalian blood Factor Xa in relative proportions just sufficient to arrest bleeding.
By another aspect of this invention there is provided a method for controlling bleeding in mammals comprising administering intravenously to said mammal a synergistic mixture of phospholipid vesicles and mammalian Factor Xa in relative proportions and in an amount just sufficient to arrest bleeding.
DETAILED DESCRIPTION OF THE INVENTION
It is well known that blood coagulation proceeds by a series of activation steps where circulating inactive clotting factors are converted to proteolytic enzymes. The final product of this cascade is thrombin (IIa) which converts the sol protein, fibrinogen, to its gel form fibrin which is the basic constituent of a blood clot. Factor VIII:C is not a proteolytic enzyme but a potent cofactor of the activation step in which Factor IXa activates Factor X to Xa. Indeed Factor VIII:C is a rate limiting factor, in the absence or reduction of which activation of Factor X to Factor Xa is prevented or minimized even the presence of normal levels of all other clotting factors. It is known that the complex of Factor Xa, Factor V and calcium responsible for the conversion of prothrombin (Factor II) to thrombin (Factor IIa) is assembled on a phospholipid surface provided by the platelet. It is believed that the synergistic effect of highly-purified factor Xa in combination with PCPS vesicles provides a close approximation of the physiological event. The remaining components of the complex, i.e. Factor V and ionized calcium, being unaffected by the availability of Factor VIII:C, are available in the recipient's blood. Studies have demonstrated true synergism between the two components, i.e. Factor Xa and P/CP/s vesicles, in vivo. Decreasing the dose of Factor Xa can be accommodated by increasing the dose of PCPS and vice versa in achieving the same endpoint, i.e. thrombin generation. It is now known, however, that thrombin has multiple roles in vivo and some of these are mutually antagonistic. Thrombin is the proteolytic enzyme required for the conversion of fibrinogen to fibrin. It is also known that thrombin is required to activate a Vitamin K-dependent protein, Protein C, which is a potent anticoagulant. This anticoagulant effect is achieved by the inactivation of the critically important cofactors, Factors VIII:C and V. It also appears to expert significant control over the fibrinolytic mechanism, i.e. the mechanism responsible for clearing fibrin formed by the conversion of fibrinogen by thrombin. It has been demonstrated that activated Protein C requires a phospholipid surface in order to exert its anticoagulant effect. Consequently, the Factor VIII:C bypassing effect, in achieving hemostasis, requires a critical dose ratio of Factor Xa to PCPS. This is calculated on a dose/kg body weight basis. The dose of Factor Xa is critical. Above a given level, unacceptable toxicity (thrombogenicity) occurs whereas below a certain level, a hemorrhagic tendency is produced in normal animals, i.e. VIII:C replete animals, presumably due to the relative excess of phospholipid favouring the anticoagulant effect of activated Protein C.
Factor Xa may be obtained by fractionating plasma from normal donors to obtain the precursor zymogen Factor X which can then be activated by known procedures (Bajaj et al. J. Biol. Chem. 248:7729, 1973; Downing et al. J. Biol. Chem. 250:8897, 1975). Factor Xa may be stored indefinitely in 50% glycerol at -20° C. The amount of Factor Xa in the dosage form is extremely small and sufficient quantities to treat large numbers of hemophiliacs can be derived from a small number of blood donors, in comparison to the many thousands required for the provision of more conventional therapy. This has distinct advantages, apart from the obvious one of economy. The accidental transmission of infection is a major hazard of multiple transfusion practice in patients such as hemophiliacs. Hepatitis and acquired immunodeficiency syndrome are major problems. By restricting the number of donors required, careful screening for these problems may be effected thus drastically reducing if not eliminating the risk. Furthermore, the purified Factor Xa, unlike many of the blood products presently used can be sterilized with relative ease, and in comparison to Factor VIII:C is relatively stable thus making it more suitable for use in areas where sophisticated hospital facilities are not available.
Phosphatidylcholine (PC) and phosphatidylserine (PS) are available commercially as semi-purified reagents. they are prepared from egg yolks and bovine brain respectively. The PCPS lipid vesicles may be prepared by a conventional and standardized protocol (Nesheim et al, J. Biol. Chem. 254: 10952, 1979 and Barenholz et al Biochem. J. 16:2806, 1976) which produces single compartment vesicles of uniform dimension (325-350Å) which may be stored at 4° C. for 2 to 3 weeks. The molar ratio of phosphatidylserine to phosphatidylcholine is about 1:3, based on the relative amounts of these lipids used in the preparation of the vesicles.
The Factor Xa-PCPS mixture is freshly prepared by mixing Factor Xa and PCPS in the desired ratio immediately prior to use.
In order to demonstrate the efficacy of the treatment, tests have been carried out on both normal and specially bred hemophilic dogs, maintained on water adlibitum and regular dry dog Chow (Ralston-Purina, St. Louis, Mo.), as described in detail in Examples 1-10 hereinafter. In all cases the animals were anesthetized with a rapid acting intravenous barbiturate 5%-18 mg/kg body weight. A continuous infusion was established via a 21 gauge butterfly needle in the cephalic vein using isotonic saline for injection to keep the vein open. All medications were administered via this route. All hair was clipped from around the animal's claws and silicone grease was applied to prevent blood from tracking back beneath the claw. A spring loaded sliding blade guillotine was used to sever the apex of the nail cuticle which was visualized or located in relation to the dorsal nail groove. Blood was allowed to fall freely by positioning the paw over the edge of the operating table. In normal dogs bleeding stops abruptly (mean 6.0 +3.7 (S.D.) mins) whereas in hemophilic animals bleeding may stop transiently but always restarts and continues until arrested by the application of silver nitrate (Blood, Vol. 60, No. 3, P727-730 Sept. 1982). In all cases the dosage of Factor Xa/PCPS was administered on a dose/kg body weight basis. The dose of PCPS is unitized in arbitrary units. 1 Arbitrary unit PCPS equals 1×10 -8 moles of phospholipid as assayed by an inorganic phosphorus assay. Factor Xa is unitized according to an internationally accepted classification in which 1 unit of Factor X is the amount present in 1 ml of normal plasma and 1 unit of Factor Xa is the amount of activity present when 1 unit of Factor X is fully activated. The assay is standardized by measuring activity in the test preparation against the activity in a normal pool plasma standard as described by Suomela H et al (Thrombosis Research 10:267, 1977) as modified by Giles A. R. et al (Thrombosis Research 17; 353, 1980).
EXAMPLE 1
A normal dog was tested as described above, by cutting the cuticle of the right hind nail 4. Bleeding stopped spontaneously at 5 minutes but rebleeding occurred at 9 minutes for a further 3 minutes. 15 minutes after the start of the first cuticle bleeding time, the animal was infused with PCPS/Xa at a dose of 40 units and 0.05 units/kg body weight respectively. 2 Minutes after this infusion, the right hind nail 3 was severed. Bleeding continued for 12 minutes and the cuticle require cautery with silver nitrate application. 60 Minutes after the infusion of PCPS/Xa, the right hind nail 2 was severed but bleeding ceased spontaneously after 7 minutes. It will be noted that the cuticle bleeding time was initially normal but became abnormal immediately after the infusion of PCPS/Xa at this dosage suggesting that the relative excess of PCPS had favoured the anticoagulant effect of activated Protein C, thus compromising the generation of fibrin normally required to cause bleeding to stop. This effect had dissipated 60 minutes after the infusion of PCPS/Xa.
EXAMPLE 2
The procedure of Example 1, showing the effect of PCPS/Xa at a dosage of 40 units and 0.05 units/kg body weight respectively on the cuticle bleeding time of a normal dog was repeated. The cuticle of the left front nail 1 was severed and bleeding arrested spontaneously after 3 minutes. 13 Minutes after the start of the first cuticle bleeding time, a bolus infusion of PCPS/Xa was given at a dosage of 40 units/0.05 units/kg body weight. 2 Minutes after the infusion, left front nail 3 was severed and bleeding continued for 12 minutes until arrested by silver nitrate cautery. 60 Minutes after the infusion of PCPS/Xa, left front nail 2 was severed and bleeding arrested spontaneously after 3 minutes. The results obtained are virtually identical to those given in Example 1 and the same conclusion is drawn.
EXAMPLE 3
The same cuticle bleeding time procedure as in Examples 1 and 2 was used in a hemophilic dog (Factor VIII:C level<4%). The right front nail 4 was severed and bleeding continued for 14 minutes until PCPS/Xa at a dosage of 8.0 units and 0.2 units/kg body weight respectively was infused as a bolus. Bleeding stopped abruptly but 2 small rebleeds (1 drop in each case) occurred at 18 and 23 minutes post the start of cuticle bleeding time number 1. 1 Minute prior to the infusion of PCPS/Xa, the right front nail 3 was severed but bleeding arrested 30 seconds after the administration of PCPS/Xa. It should be noted that the observation period was not continued beyond 30 minutes post the start of the cuticle bleeding time number 1. These results demonstrate that the combination of PcPs/Xa, at the dosage used, bypasses Factor VIII in causing the arrest of bleeding in a Factor VIII:C deficient animal. The injured cuticles of such animals would normally bleed until cauterized with silver nitrate. Immediately following the infusion, the animal exhibited apnea and cardiac rhythm irregularities but these resolved spontaneously within 5 minutes after the infusion.
EXAMPLE 4
The procedure of Example 3 was repeated using a different hemophilic animal (Factor VIII:C<1%). The right hind nail 1 was severed and bleeding until a bolus infusion of PCPS/Xa at a dosage of 8.0 units and 0.2 units/kg body weight respectively was administered at 16 minutes post the start of the cuticle bleeding time number 1. 1 Minute prior to the administration of PCPS/Xa, the right hind nail 2 was severed but bleeding arrested within 30 seconds of administration of PCPS/Xa. Rebleeding occurred 12 minutes later and continued for 17 minutes until arrested by silver nitrate cautery. 18 Minutes after the administration of PCPS/Xa, the right hind nail 3 was severed and bleeding continued for 12 minutes until arrested by silver nitrate cautery. Immediately following the infusion of PCPS/Xa the animal had a transient cardiopulmonary arrest but regained his vital signs within 2 minutes without resuscitation other than the application of 100% oxygen via a face mask. These results confirm the Factor VIII bypassing activity of a combination of PCPS/Xa at this dosage. The cardiopulmonary side-effects suggest borderline toxicity at this dosage. The rebleeding of right hind nail 2 and the abnormal cuticle bleeding time of right hind nail 3 suggests that the Factor VIII:C bypassing effect is transitory.
EXAMPLE 5
A hemophilic dog, as in Examples 3 and 4 was tested as described above. The right hind nail 2 was severed and bleeding from the cuticle stopped with silver nitrate after 12 minutes. The left hind nail 1 was severed and 2 minutes thereafter PCPS/Xa at a dosage of 4.0 units and 0.1 units/kg body weight respectively was infused. Bleeding continued for a further 10 minutes until arrested by silver nitrate cautery. The animal did not exhibit toxicity but bleeding was not arrested by this dosage of PCPS/Xa.
EXAMPLE 6
The procedure followed in Example 5 was repeated in a different hemophilic dog and with the dose of Factor Xa increased to 0.2 units/kg body weight in combination with PCPS at a dose of 4.0 units/body weight. The right hind nail 1 was severed and bleeding continued for 15 minutes until the PCPS/Xa combination was administered as a bolus infusion. Bleeding stopped abruptly but reoccurred at 27 minutes and continued thereafter until 40 minutes when it was arrested by silver nitrate cautery. 1 Minute prior to the infusion of PCPS, the right hind nail 2 was severed but bleeding ceased within 20 seconds of the infusion of PCPS/Xa combination. Bleeding recommenced 12 minutes later and continued for 13 minutes until arrested with silver nitrate cautery. No cardiopulmonary toxicity was observed. As compared with the result of Examples 3 and 4, a 50% reduction of the dosage of PCPS did not compromise the Factor VIII:C bypassing activity observed in the hemophilic animals. In comparison with Example 5, doubling the dose of Factor Xa in combination with 4 units of PCPS achieved by the lower dosage of Factor Xa in combination with the same dosage of PCPS.
EXAMPLE 7
The procedure of Example 6 was repeated on another hemophilic dog with the dosage of Factor Xa being maintained but the dosage of PCPS being further reduced to 0.1 unit/kg body weight. The left front nail 5 was severed and bleeding continued for 16 minutes but was arrested abruptly by the infusion of PCPS/Xa. No rebleeding occurred during the period of observation. 1 Minute prior to the infusion of PCPS/Xa, the left front nail 4 was severed and bleeding was arrested within 1 minute of the infusion of PCPS/Xa but reoccurred 4 minutes later and continued for 22 minutes until arrested by silver nitrate cautery. 15 Minutes after the infusion of PCPS/Xa, the left front nail 3 was severed and bleeding continued for 12 minutes until arrested by silver nitrate cautery. These results show that a further significant reduction in PCPS/Xa dosage is still associated with Factor VIII bypassing activity but that the effect is less well maintained.
On the basis of these studies, all of which have been carried out on a dog model using Factor Xa derived from bovine blood, it is believed that the minimum dose of Factor Xa required is 0.2 units/kg body weight of PCPS vesicles. Tests have confirmed similar results using Factor Xa derived from canine blood and human blood. Infusion of either of these components alone have been shown to have no effect in correcting the cuticle bleeding time of Factor VIII:C deficient animals nor are they thrombogenic. However, it is stressed that Factor Xa in combination with PCPS is an extremely potent reagent and as little as 0.5 units/kg body weight may be sufficiently toxic, i.e.. thrombogenic, to cause death. As the combination of Factor Xa and PCPS is synergistic, lower doses of Factor Xa may become toxic (i.e. thrombogenic) when combined with higher doses of PCPS. The examples given suggest that threshold toxicity of Factor Xa at a dosage of .02 units/kg body weight is achieved when combined with PCPS at a dosage of 8 units/kg body weight. This ratio of PCPS to Xa (40:1) is considered to be the practical maximum whereas the ratio of PCPS 1 unit to Xa 0.2 units (5:1) is considered to be the practical minimum.
It is also emphasized that these studies have been carried out on a dog model and although this model is believed to simulate the human disease of classical Hemophilia A (Factor VIII:C deficiency) very closely, the specific ratios between and the actual dosage of, PCPS and Factor Xa in the synergistic mixture thereof may vary somewhat from those determined in the dog model.
All of the above studies have concentrated upon the control of hemophilia in mammals, and in particular in dogs. The intravenous infusion of the PCPS/Factor Xa mixture of the present invention into normal mammals has, however, been shown to reduce normal bleeding times significantly, thus providing a new method for controlling bleeding in certain, generally traumatic situations. For example a battlefield medic may give a suitable injection to a battle casualty to control major bleeding before evacuation; a surgeon may require rapid cessation of bleeding during routine or emergency surgery; and even paramedics at the scene of an accident could usefully employ the technique to control bleeding prior to transfer of the victim to hospital.
In order to demonstrate the efficacy of the treatment the following experiments were carried out on normal mongrel dogs maintained on water ad libitum and regular dry dog chow (Ralston-Purina, St. Louis, Mo.), as described in detail in examples 8-10 hereinafter. The same experimental protocol as that used in examples 1-7 was employed.
In normal dogs, bleeding stops abruptly (mean 6.0+3.7 (S.D.) minutes). this method is fully described in the journal "Blood" 60:727-730, September 1982. In the performance of the tests described in the examples hereinafter, sequential bleeding times were performed on each animal and, exactly 30 seconds after the initiation of the cuticle injury, either a bolus of saline or the test material (Factor Xa/PCPS) was administered and the duration of bleeding post-infusion determined. The volume of saline given was identical to the total volume of the mixture of Factor Xa and PCPS.
EXAMPLE 8
A normal dog was tested as described above by cutting the cuticle of the left hind nail 1. exactly 30 seconds later, a bolus of 15 ml of isotonic saline for injection was given and bleeding continued for 150 seconds. Fourteen minutes after initiating the first cuticle injury, the cuticle of left hind nail 2 was injured in an identical fashion and, precisely 30 seconds, Factor Xa/PCPS was given. The dose of PCPS/Xa was 4.0 units/0.2 units per kg body weight respectively in a total volume of 15 ml. Bleeding stopped within 30 seconds following the infusion. This result suggested that the infusion of Xa/PCPS significantly accelerated the hemostatic process in stopping bleeding in a normal animal.
EXAMPLE 9
The same procedure used in Example 8 was used with a minor modification. A second normal mongrel dog was used. The cuticle of left hind nail 1 was injured and, precisely 30 seconds later, a bolus of saline was administered. Bleeding continued for 90 seconds. Fourteen minutes after the injury to the first cuticle, the cuticle of left hind nail 2 was injured and, 90 seconds later Factor Xa/PCPS was administered at an identical dose to that used in Example 8. Bleeding ceased within seconds of the bolus infusion of Factor Xa/PCPS. This example further suggested that Factor Xa/PCPS accelerated the normal hemostatic process.
EXAMPLE 10
An identical procedure was used to that described in Example 8. A third normal mongrel dog was used. the cuticle of right hind nail 4 was injured and, precisely 30 seconds later, 15 ml of isotonic saline for injection was infused. Bleeding continued for 90 seconds. Fourteen minutes after the first injury, the cuticle of right hind nail 3 was injured and, precisely 30 seconds later, Factor Xa/PCPS, at a dose identical to that used in Examples 1 and 2, was infused. Bleeding stopped within 30 seconds. This example further illustrated that Xa/PCPS accelerated the normal hemostatic process.
On the basis of these studies, it would appear that a combination of Factor Xa/PCPS accelerates and probably reinforces the normal hemostatic process. Consequently, it could have useful applications in inducing primary hemostatis in emergency situations in traumatized normal individuals. It could also have applications to all congenital and acquired hemostatic deficiency states of hemostatis other than deficiencies of prothrombin as it is assumed that the mechanism by which hemostasis is achieved by Factor Xa/PcPS results from a generation of thrombin from prothrombin induced by the infusion of Factor Xa together with PCPS as an inducer of prothrombin to thrombin conversion. Similarly, as fibrinogen is the substrate for thrombin, it can be assumed that deficiency states of this protein would not be amenable to therapy with Factor Xa/PCPS. | Factor VIII:C deficiency in a hemophilic mammal may be bypassed by infusion of a synergistic mixture of a phospholipid and Factor Xa so that the cascade process of blood clotting may continue. The proportions of phospholipid and Factor Xa in the mixture are critical as too little Xa has no effect while too much is toxic (thrombogenic). Infusion of the phosphilipid-Factor Xa mixture into normal mammals enhances the natural clotting rate and provides a method for rapidly controlling bleeding in emergency situations. |
Applicant claims the benefit of provisional patent application No. 61/004,631 filed Nov. 30, 2007.
FIELD OF THE INVENTION
The instant invention is for a device to be used for the practice of fly-fishing. The device is used to connect the fly line to the leader line or tippet.
BACKGROUND OF THE INVENTION
The practice of fly-fishing typically requires the fisherman to make some sort of tension resisting connection between the weighted fly line (normally tapered, and coated with a semi-resilient polymer) and a leader line (clear or slightly tinted) to which the artificial fly, nymph or other fish attracting lure is terminally attached. These two lines, the fly-line and leader-line are designed with very different attributes and are not most effectively or reliably connected to each other using knots, even those developed specifically for this purpose.
This fly line to leader connection problem is addressed by a number of prior art devices, all of which have inherent advantages and disadvantages. One of the best prior art solutions is disclosed in detail in the U.S. Pat. Nos. 3,717,907 and 3,834,061. These patents disclose a small, flexible plastic link with transverse openings at each end to receive the leader and fly line respectively. The line ends are threaded through these transverse openings to project through a side opening in the link. The extending line ends are then both tied in knots that are then trimmed and pulled back into the link where they are held secure. This leader connector device is reasonably reliable in maintaining tension between the two lines when the knots are carefully tied. In practice, it is often fairly difficult to re-insert the knot end of the fly line back into the link, due to the size interference between the fly line knot and the link slot. It is often necessary to try and strip off some of the fly line surface coating before tying the knot in an attempt to reduce the overall knot size, but this is difficult to do without damaging the tensile bearing core. There is sometimes the additional problem of tying the leader knot with a sufficient cross section to keep it from being pulled transversely through the link. The practical necessity to tie an overhand knot in the fly line and a clinch knot in the leader and then to seat these knots within the very confined space of the link slot along with the relatively large link diameter (as compared to the fishing lines) has made this fly-line to leader link a less than desirable solution to a large number of fly fishing practitioners.
Currently, the most popular fly line to leader connection device is referred to as a “braided loop”. These braided loops are somewhat difficult to install as they must be progressively expanded and pulled (teased) over the terminal end of the fly line. Once installed, they are held secure to the fly line in the same manner that a woven “Chinese finger trap” (children's novelty toy) grips a finger. This gripping action works to secure these braided loops because the polymer coating of the fly line has a semi-resilient surface covering. This semi-resilient surface allows the braided mesh to grip the line when the braided loop and fly line are placed in tension. Unfortunately, installing these braided loops always results in the fraying of the braided tubular opening of the device. This frayed end must be covered with a heat shrink or elastic tubing to keep it from further fraying and to prevent the frayed edge from getting snagged on the fishing rod guides or other obstructions or snags as typically encountered while fishing. Failure to cover this frayed end will typically result in the braided loop being pulled off the fly line. The installation difficulties and performance drawbacks of the braided loops are actually more serious than the fly line to leader connector links as described above, but they remain very popular. There are numerous other connector devices in the prior art for connecting the fly fishing line to the leader line but they use structurally rigid clamping jaws or external barbs (U.S. Pat. Nos. 4,864,767 and 5,469,652) to secure them to the fly line. In order to maintain sufficient clamping pressure or structural rigidity to keep the ridges or barbs engaged, these connectors are larger and heavier than is desirable for use with fly fishing lines. There are also some specialized fly lines and leaders with a built in connection means (U.S. Pat. Nos. 5,469,652 and 6,880,289). These specialized connecting lines have to be used exclusively with each other, and as a result are limiting to the flexibility of line and leader setup by the fisherman. These specialized devices also tend to be larger in size than is desirable. None of the prior art connection devices makes use of a light, flexible, compressively expandable tubular lattice structure to make a reliable, in-line, and very streamlined connection between the fly line and leader line.
The prior art braided loops will be described in more detail in the accompanying Detailed Description section with reference to the “prior art” patent application FIGS. 1 through 3 . The instant Fly Line Connecting Device is described in the accompanying Detailed Description section and the details are shown in the application FIGS. 4 through 24 .
SUMMARY OF THE INVENTION
It is the primary objective of the instant invention to provide an improved connector device for attaching the leader line or tippet to a fly fishing line. The key feature of this improved connecting device is the development of an elastically compressible tubular lattice that is of a unitary or unwoven structure. This flexible tubular lattice structure allows for a small, light and streamlined, in-line connection of the device to the fly-line. The manufacture of this tubular lattice feature is most easily achieved by the injection molding of an intermediate configuration having oversized dimensions. Once the intermediate configuration is injection molded, the device may be manually or machine “cold drawn” (stretched) to reduce the tubular lattice inside diameter, wall section and to greatly increase the tensile strength and toughness. The cold drawing operation, whether performed by the fisherman or completed at the end of the molding cycle, is facilitated by the incorporation of integrally molded stretching loops or other holding features. These stretching loops are clipped off the device by a secondary manufacturing operation or by the fisherman before the device is installed over the fly line. Installing the device is performed by distally compressing the tubular lattice and thereby expanding the inside diameter to allow for the progressive insertion of the fly line. Once the fly line is fully inserted, the fisherman releases the compressive force and the tubular lattice contracts down to constrict the fly line. It is important to note that the in the relaxed state (not compressed), the tubular lattice inside diameter is somewhat smaller than the fly line diameter so that it will elastically grip the fly line. The expandable tubular lattice tightens down and grips the fly line even more securely when a tension force is applied.
An assembly aid in the form of a longitudinally slit or trough shaped tube may be supplied to support and constrain the tubular lattice portion of the device while the fly-line is being inserted.
There are a number of different options and associated features for attaching the leader line or tippet to the connector device. The leader line or tippet may be tied directly or looped with an integrally formed loop or eyelet. Alternatively, the leader line or tippet may be affixed to the device using a very small knot-trapping feature. The leader line or tippet being typically much smaller in diameter than the fly line can be secured within the knot holding feature using a relatively small overhand knot. An advantage of using the knot holding feature over the loop or eyelet is that the connection between the lines is very small and streamlined and this connection maintains axial alignment and stiffness between the lines. The axially aligned connection does not pivot or hinge as loop connections tend to do, thus preserving the fly-casting energy and accuracy. This fly line connecting device has substantial advantages over the existing knots and connection devices by virtue of being very lightweight, streamlined (low air/water resistance), and axial stiffness or resistance to pivoting or hinging at the connection junction.
The preferred embodiment of the Fly-Line Connecting Device is injection molded using nylon, polyester, fluorocarbon or any other high molecular weight plastic that can be “cold drawn”. The connection device will typically be made with a high visibility color so the device may function secondarily as a strike indicator.
BRIEF DESCRIPTION OF THE DRAWINGS
The patent figures are intended to demonstrate some, but not necessarily all of the design configurations for the Fly-Line to Leader Connecting Device. It is important when looking at the drawing figures to understand that this connecting device is very small. The tubular lattice portion of the device typically fits over a fly-fishing line that ranges approximately from 0.030″ to 0.060″ diameter. It is for this reason, and to clearly show the details of the connecting device, that the patent figures show the Fly-Line To Leader Connecting Device drawn larger than true scale.
FIG. 1 depicts a front view of the “prior art” braided splice;
FIG. 2 depicts a front view of the “prior art” braided splice with the fly-line and heat shrink tubing partially installed;
FIG. 3 depicts a front view of the “prior art” braided splice with the fly-line fully inserted and the heat shrink tubing shrunk down over the frayed end;
FIG. 4 depicts an enlarged front view of the fly-line to leader connecting device of the instant invention;
FIG. 5 depicts an enlarged front view of the device of FIG. 4 after the device has been cold drawn;
FIG. 6 depicts a side view of the fly-line to leader connecting device with the stretching loops being mounted over two pencils, just prior to being cold drawn;
FIG. 7 depicts a side view of the fly-line to leader connecting device with the stretching loops being mounted over two pencils after cold drawing;
FIG. 8 depicts an isometric view of the fly-line to leader connecting device prior to cold drawing;
FIG. 9 depicts an isometric view of the fly-line to leader connecting device after cold drawing;
FIG. 10 depicts an isometric view of the fly-line to leader connecting device with the pulling loops clipped off and the device installed over the end of a fly fishing line;
FIG. 11 depicts an enlarged isometric end view of the device of FIG. 10 ;
FIG. 12 depicts an enlarged partial section of the device of FIG. 10 showing the details of the knot trap and leader line attachment.
FIG. 13 depicts a front view of an alternate configuration of the fly-line to leader connecting device;
FIG. 14 depicts an enlarged isometric detail view of the tubular lattice of the alternate configuration of the fly-line to leader connecting device of FIG. 13 ;
FIG. 15 depicts a front view of the alternate configuration of the fly-line to leader connecting device of FIG. 13 after it has been cold drawn;
FIG. 16 depicts a front view of the alternate configuration of the fly-line to leader connecting device of FIG. 15 with the pulling loops clipped off and the device installed over the end of a fly-fishing line;
FIG. 17 depicts an enlarged isometric detail view of the cold drawn tubular lattice of the fly-line to leader connecting device of FIG. 16 ;
FIG. 18 depicts an isometric view of the fly-line to leader connecting device being installed over the fly-fishing line using a tubular assembly aid;
FIG. 19 depicts an enlarged isometric detail view of the fly-line to leader connecting device of FIG. 18 being installed using a tubular assembly aid;
FIG. 20 depicts an isometric view of the fly-line to leader connecting device with an integral tippet with loop;
FIG. 21 depicts an isometric view of the device of FIG. 20 after it has been cold-drawn;
FIG. 22 depicts an isometric view of the device of FIG. 21 with the pulling bar clipped off and the device installed over the end of a fly-fishing line;
FIG. 23 depicts an isometric view of the fly-line to leader connecting device configured for permanent attachment to a full length leader line;
FIG. 24 depicts an isometric view of the fly-line to leader connecting device with a permanent attachment of a fill-length leader line.
DETAILED DESCRIPTION
The prior art “braided loop” device 11 is shown in the FIGS. 1 through 3 . The device 11 as shown in FIG. 1 is formed of a braided (nylon) tubular sleeve 19 with a hand formed loop at 15 . The loop 15 is made by tucking the end of the braided sleeve back into a stretched region of the weave where it is secured by cementing approximately 1″ of overlapping length of the braided nylon as seen at 17 . The braided tubular sleeve 19 has an open tubular end to receive the fly line at 21 . The FIG. 2 shows the fly line 23 being pushed into the expanded woven sleeve 19 . The braided sleeve 19 opens up to receive the fly-line 21 as it is locally compressed. In order to get the fly line 23 fully inserted into the braided loop sleeve 19 it is necessary to tease the line further and further up the braided sleeve. This procedure is somewhat tedious as both the fly line and braided loop are prone to flexing. The braided loop device 11 stays in place on the fly-line 23 by a mechanism similar to how a Chinese finger trap (child's toy) stays affixed over a finger. The handling required to push the fly line 23 into the braided loop 11 always results in the fraying or unraveling of the woven fibers at the sleeve opening 21 as seen in FIG. 2 . This unraveling of the braided loop opening during installation of the fly line is a significant problem with this braided loop design. In order to prevent snagging of the braided loop and the possibility of the device slipping off the fly line 23 , it is necessary to cover this frayed area with a length of heat shrink tubing 25 as seen in FIG. 3 . The necessity to cover this frayed area 21 with heat shrink tubing 25 or in some cases flexible tubing is a major drawback associated with using these braided loops. The heat shrink tube, requiring a heat source capable of reaching temperatures over 230° F. is difficult to apply, adds significant weight and does not always remain securely in position. The braided loops can slip off the fly line if the heat shrink tubing does not stay in position or any of the many obstacles or snags as one typically encounters while fishing come into contact with this edge region during line retrieval. A further disadvantage of these braided loops is that the fly line engagement length is reduced and weight is increased by the approximate 1″ length of overlap that is used to form the loop 15 . Finally, the loop 15 to which the leader is attached is quite large as compared to the fly line and leader line diameter. The loop 15 tends to snag on rod guides and can contribute to excessive water and wind resistance during casting and/or retrieval of the fly line. Finally, the loop 15 is the only available leader line affixing option that is available with these braided loops 11 .
Referring to the drawing FIGS. 4 and 5 , there is shown the Fly Line Connecting Device or connector 31 consisting of an expandable tubular lattice 33 and a connecting loop 35 , adapted to be inter-looped (connected) with the leader line. Alternatively, a cylindrical knot trap 43 is provided as a more streamlined alternative for attaching the leader line using a small knot. The fly line to leader connecting device 31 has stretching loops 37 and 39 located at the opposite distal ends. These loops 37 and 39 are used as an aid in cold drawing or stretching the device to the working dimensions as shown in FIG. 5 . The cold drawing of the connecting device 31 is important for the following reasons:
The cold drawing process re-orients the polymer molecules linearly along the cold-drawing axis, adding substantially to the tensile strength and toughness of the stretched sections of the tubular lattice 34 . The resultant decree in cross section that accompanies the cold-drawing operation makes it possible to have a thin, flexible, and somewhat “springy” fly line gripping tubular lattice 34 .
Since the preferred manufacturing method is by injection molding, the cold drawing allows for molding the device in an intermediate condition where the length and wall section are sufficiently large to allow for an adequate flow of the plastic polymer to fill the mold.
The leader connecting device 31 feature cross sections can be manipulated to allow some areas of the device to be cold drawn while other thicker regions maintain their “as-molded” dimensions. This can be seen as one compares the characteristics of the leader connecting device features from the FIG. 4 to the FIG. 5 . It can be seen that the cold drawn tubular lattice 34 has been stretched by approximately three times (3×) the original length and the diameter decreased by approximately two times (2×). The thicker cross section features such as the leader connecting loop 35 and knot trap 43 are not cold drawn. The distally located stretching loops 37 and 39 are also not cold-drawn. It may be found for some applications of the Fly Line Connecting Device 31 that any one of these “not” cold-drawn features may be configured with a smaller cross section to allow for cold drawing.
Referring to FIGS. 6 and 7 , there is shown the Fly Line Connecting Device 31 having the stretching loops 37 and 39 secured over a pencil before ( FIG. 6 ) and after the cold drawing or stretching operation ( FIG. 7 ). These figures show an embodiment of the connecting device 31 that has a tubular lattice 33 cross sectional area that is small enough to allow the fisherman to manually cold-draw the device. Alternatively, the connecting device 31 may be cold drawn prior to sale using a specially designed injection mold or stretching fixture in a secondary manufacturing operation. Reference the U.S. Pat. No. 4,178,342 for disclosure of injection molding combined with cold drawing operation. This machine cold-drawing may be desirable, especially if it is found that a slightly larger cross sectional area for the tubular lattice is required for higher tensile strength or to make the manual insertion of the fly line easier.
Referring to the drawing FIGS. 8 , 9 and 10 , there is shown the Fly Line Connecting Device 31 having both a leader connection loop 35 and knot trap feature 43 for attaching the leader or tippet line. The drawing FIGS. 8 , 9 and 10 show the sequence of operations to cold-draw, clip and install the fly line connecting device 31 over the fly line 23 . The FIG. 8 shows the device 31 in the as molded or intermediate form. The circular feature 41 located on the back of the stretching loop 39 is an artifact from the injection mold core pin that forms the inside of the tubular lattice 33 and the inside features of the knot trap 43 . This artifact feature 41 has no specific function other than allowing the stretching loop 39 to be located in-line with the center of the tubular lattice 33 . It is desirable to keep the stretching loops 39 and 37 centered with the tubular lattice 33 to simplify the injection mold and to prevent any shear force distortion when the device 31 is cold drawn. The FIG. 9 shows the device 31 after it is stretched or cold-drawn. The only feature that is small enough in cross section to be cold drawn is the tubular lattice 34 . The FIG. 10 shows the fly line 23 pushed up into the compressibly expanded tubular lattice 34 after the loops 37 and 39 have been clipped off. The connecting device 31 is now ready for the loop 35 or knot trap 43 connection of the leader line.
Referring to the drawing FIGS. 11 and 12 , there is shown an enlarged view of the Fly-Line Connecting Device 31 . The drawings show the cold drawn tubular lattice 34 as it elastically “grips” the semi-resilient surface of the fly line 23 . The tubular lattice 34 has a “functional geometry” that acts to expand the inside diameter when it is axially compressed. It can be seen from the drawing FIGS. 11 and 12 that the expandable tubular lattice 34 is a unitary structure with no interweaving. The expanding and contracting action of the connection device tubular lattice 34 may look similar to that of the prior art braided loop, but it is based on an entirely different mechanism. The prior art (interwoven) braided loops expand and contract by the loosening and tightening action of the weave—just like a Chinese finger trap. The expanding and contracting action of the tubular lattice 34 is due to the opening (expansion) and closing (contraction) action of the openings in the lattice of the tubular web. It is important to note that the unitary structure of tubular lattice 34 is not subject to flaying at the opening. In order for the post drawn tubular lattice 34 to effectively clamp on the fly line 23 as seen in the FIGS. 11 and 12 it is necessary that the internal diameter of the tubular web (after cold drawing) be slightly smaller than the outside diameter of the fly line 23 . This dimensional interference between the inside diameter of the tubular lattice 34 and the outside diameter of the fly line 23 does not need to be very large, (approximately 0.005″ to 0.010″) but it must be sufficient to prevent the connecting device 31 from slipping off the fly line 23 when there is low or no tension. It can be seen that the tubular lattice 34 portion of the fly-line connecting device will constrict onto the fly-line 23 even tighter (holding more securely) when they are placed in tension. This constricting action of the tubular lattice is critical if the connecting device of the instant invention is to hold the fly-line and leader lines together under the tensile forces that occur during fly-casting, line retrieval, and playing the fish.
The connection device 31 has both a leader connection loop 35 and a knot trap 43 for attaching the leader or tippet line. The patent FIG. 12 shows a partial cross-section of the knot trap 43 with the leader line or tippet 51 held in place by using a small overhand knot 53 . The connection loop 35 can be clipped off if the knot trap 43 and leader knot 53 is used to attach the leader line 51 . Although some fishermen prefer to make an inter-looped connection between the fly line and leader, they may come to appreciate that using the knot trap 43 allows for a very streamlined, axially supported connection between the fly line and the leader line.
Referring to the drawing FIGS. 13 , 14 and 15 , there is shown an alternate embodiment of the Fly Line Connection Device 55 . This connection device 55 has stretching loops 57 and 59 and eyelets 61 and 65 . This device employs a tubular lattice 63 as seen in detail in FIG. 14 . This simplified geometry tubular lattice 63 was developed to allow for molding using a simple two-sided injection mold. The FIG. 15 shows the connection device 55 following the cold drawing operation. It can be seen in FIG. 15 that except for the stretching loops 57 and 59 , the entire device 55 , including the eyelets 62 and 66 are cold drawn.
The drawing FIG. 16 and detail FIG. 17 show that this alternative embodiment Fly Line Connection Device 55 is attached to the fly-fishing line 23 in an equivalent manner to the device shown in the previous FIGS. 10 , 11 and 12 . The FIG. 17 shows the cold drawn expandable tubular lattice 64 gripping the fly line 23 . The connection device 55 has a tubular eyelet 62 for attaching the leader or tippet line. This tubular eyelet 62 may allow the leader line, once tied on there, to be threaded back up through the tube center to the tube end at 67 to make a streamlined connection. This alternative embodiment of the fly line connecting device 55 may be fabricated using a process of perforating or laser cutting a thin walled extruded tube, but this is probably not as economical as injection molding. If the device 55 were to be manufactured from perforated tubing, it would be necessary to include an extra length of tubing at both ends to assist the fisherman in holding the ends for cold drawing.
Looking at this alternative embodiment of the connection device 55 it should be apparent that there are other options for the expandable tubular lattice geometry, such as intersecting helical curves (clockwise and counter-clockwise) that would have an equivalent functional geometry or fly line gripping capability as those already detailed. It is also feasible to form an integral, and very thin walled tube on the inside of the tubular lattice by using a slightly undersized core pin in the injection-mold. In this example the lattice structure is not formed all the way through the tube and it is therefore necessary that the tube wall is thin enough to expand and contract with the lattice structure. A tubular lattice of this configuration will not grip the fly-line as securely as when the lattice openings go all the way through, but it may be helpful if there are problems with completely fining the injection mold.
Referring to the drawing FIGS. 18 and 19 , there is shown the Fly Line Connection Device 31 being held constrained in a tubular channel 71 . This tubular channel 71 has an internal diameter just slightly larger than the outside dimension of the cold drawn tubular lattice 34 after the fly line 23 has been installed. The tubular channel 71 is used as an assembly aid to assist the fisherman in threading the fly line 23 up into the tubular lattice 34 . The tubular channel 71 assembly aid works by keeping the tubular lattice 34 from bending sideways while it is being axially compressed for insertion of the fly line 23 . The tubular channel 71 may be a longitudinally cut or slit length of extruded tubing supplied with the Fly Line Connection Device(s). Alternatively a tubular channel assembly aid may be injection molded or designed as part of the connector device injection mold runner system.
Referring to the drawing FIGS. 20 , 21 and 22 , there is shown a Fly-Line Connecting Device 75 with a short, integrally molded, leader line or tippet 79 and leader connection loop 81 . This device 75 has an expandable tubular lattice 77 and stretching loop 85 . The other end of the device 75 shows a stretching bar 83 that is functionally equivalent to the stretching loop 85 . The stretching bar 83 or an equivalent grasping feature can be substituted for the stretching loops shown on any of the previously shown embodiments. The FIG. 21 shows the fly-line to leader connecting device 75 after it has been cold drawn. The tubular lattice 78 , short tippet line 80 , and leader connection loop 82 are noticeably longer and thinner due to the cold-drawing operation. The FIG. 22 shows the connecting device 75 installed over the fly fishing line 23 after the stretching loop 85 and stretching bar 83 has been clipped off. This “integral tippet” embodiment of the connecting device 75 shows that it is feasible to form a short length of cold drawn, tapered leader line at the end of the expandable tubular lattice. Since many fly fishermen use homemade tippet leaders tied from progressively lighter (lower tensile test) lengths of line, the connecting device 75 with a relatively short length of tapered leader and a small loop end may be very convenient for them.
The very flexible and elongated tubular form of the Fly Line Connecting Device lends itself to the option of being commercially supplied as pre-attached to a full length leader or tippet line as shown in the drawing FIGS. 23 and 24 . The fly-line connecting device 91 is shown with a cold-drawn tubular lattice 93 and a thin-walled, cold drawn tubular extension 95 . The FIG. 24 shows the connecting device 91 with a full-length leader line 51 having been inserted into the tubular extension 95 where it is secured by being cemented or welded. The tubular extension 95 may be made as an integral, but smaller diameter extension of the tubular lattice so that it can be cemented onto the leader line from the outside. As the material of the connecting device is typically the same or very similar to that used for nylon or fluorocarbon leaders, the connection between them can be very reliably made. This material equivalence also makes possible the manufacture of the fly-line connecting device integrally molded with a tapered leader. A process for making a tapered leader from a cold-drawn blank being disclosed in the U.S. Pat. No. 4,155,973. The process of cold drawing the tapered leader is simply extended through the integrally formed intermediate form, of the connector tubular lattice.
The pre-attached connecting device 91 would then be very easily attached to the fly-line 23 . This leader with a pre-attached or integrally molded connector may be quite convenient and popular with fly fisherman. This configuration of the connector 91 allows for an almost seamless dimensional and stiffness transition between the fly-line and leader line.
The expandable tubular lattice structure of the instant invention can hold or grip the fly-line securely without having to be as long as the prior art braided loop devices. This shorter length, and the development of some very high melt-flow-rate polymers, might allow for the fly-line to leader connecting device to be molded to the final dimensions without requiring stretching or cold drawing. It should be clear from this disclosure that the compressively expandable tubular lattice is the defining feature of the fly-line to leader connection device of the instant invention, whether or not it is produced using a cold drawing process. The expandable tubular lattice of the fly-line to leader connection device is not necessarily limited to being made round, but a round configuration is probably preferred as it allows a fill perimeter contact with the typically round cross-section fly-line. Since the fly-line to leader connector device is typically injection molded there are numerous options, including a loop, eyelet, knot trap, or short tippet that can be formed integrally into the connection device for attaching the leader or tippet line.
Finally, the connection point between the fly-fishing line and the leader line is a reference point that many fly fisherman desire to be clearly visible when they are fishing. When this junction is clearly marked, it is typically referred to as a “strike indicator”. Many fly-fisherman go to some trouble to add a brightly colored marking device to this fly-line to leader junction. It is for this reason that the prior art braided loops are typically made in some very high visibility colors. The fly-line to leader connecting device of the instant invention will perform as a strike indicator when it is made from a plastic resin that is highly visible and/or fluorescent colored.
I have now described my invention in considerable detail. However, it is obvious that others skilled in the art can build and devise alternate and equivalent constructions that are nevertheless within the spirit and scope of my invention. Hence, I desire that my protection be limited not by the constructions illustrated and described, but only by the proper scope of the appended claims. | The invention provides a convenient, lightweight and streamlined connecting device for attaching a leader or tippet to a fly-fishing line. The Fly Line Connecting Device is configured with an expandable tubular lattice that allows for an in-line connection to the fly line. The connection device has an integral tubular lattice sized with an internal diameter that is slightly smaller that the fly line and when compressively displaced, operates to expand the internal diameter to allow insertion of the fly line. Once the fly line is fully inserted, the tubular lattice is allowed to contract and elastically constrict onto and thereby grip the semi-resilient surface of the fly line. When the fly line and leader line are placed in tension through the connecting device, the tubular lattice acts to constrict down on the fly-line to resist separation. The connecting device of the invention is configured with a loop, eyelet, knot-trapping feature, or short tippet to allow for the convenient attachment of the leader line. Alternatively, the connecting device is permanently attached or integrally formed with a full-length leader. The preferred embodiment of the connecting device is injection molded in an intermediate form that is configured to be manually or machine cold-drawn to the final working dimensions and optimal physical properties. |
FIELD
[0001] This invention relates to the field of integrated circuit fabrication. More particularly, this invention relates to thinning the layers that are formed during the fabrication of integrated circuits.
BACKGROUND
[0002] As integrated circuits have become increasingly smaller, electrically conductive structures within the integrated circuits are placed increasingly closer together. This situation tends to enhance the inherent problem of parasitic capacitance between adjacent electrically conductive structures. Thus, new electrically insulating materials have been devised for use between electrically conductive structures, to reduce such capacitance problems. The new electrically insulating materials typically have lower dielectric constants, and thus are generally referred to as low k materials. While low k materials help to resolve the capacitance problems described above, they unfortunately tend to introduce new challenges.
[0003] Low k materials are typically filled with small voids that help reduce the material's effective dielectric constant. Thus, there is less of the material itself within a given volume, which tends to reduce the structural strength of the material. The resulting porous and brittle nature of such low k materials presents new challenges in both the fabrication and packaging processes. Unless special precautions are taken, the robustness and reliability of an integrated circuit that is fabricated with low k materials may be reduced from that of an integrated circuit that is fabricated with traditional materials, because low k materials differ from traditional materials in properties such as thermal coefficient of expansion, moisture absorption, adhesion to adjacent layers, mechanical strength, and thermal conductivity.
[0004] Low k materials are typically more brittle and have a lower breaking point than other materials. One reason for this is the porosity of the low k material, where a significant percentage of its physical volume is filled with voids. Thus, integrated circuits containing low k materials are inherently more prone to breaking or cracking during processes where physical contact is made with the integrated circuit surface, such as wire bonding and electrical probing, or processes that cause bending stresses such as mold curing, underfill curing, solder ball reflow, chemical mechanical polishing, or temperature cycling.
[0005] As integrated circuits have become smaller, they have shrunk not only in the amount of surface area required by the circuit, but also in the thicknesses of the various layers by which they are formed. As the thicknesses of the layers has decreased, it has become increasingly important to planarize a given layer prior to forming a subsequent overlying layer. One of the methods used for such planarization is called chemical mechanical polishing. During chemical mechanical polishing, the surface of the layer to be planarized, thinned, or both is brought into contact with the surface of a polishing pad. The pad and the substrate are rotated and translated relative to each other in the presence of a polishing fluid, which typically contains both physical erosion particles and chemical erosion compounds.
[0006] Unfortunately, the need to planarize the layers of an integrated circuit using traditional chemical mechanical polishing has become a problem, because the amount of down force and friction required to adequately erode a layer using chemical mechanical polishing has become great enough to crush, shear, or otherwise damage the increasingly delicate underlying low k layers as they are reduced in thickness with the general reduction in the size of integrated circuits.
[0007] For example, in copper dual damascene processing, there is a step to remove unwanted portions of a deposited copper layer from an upper surface of an integrated circuit. New integrated circuit designs place delicate low k layers somewhere beneath the copper layer to be removed. Traditional chemical mechanical polishing processes tend to be too rough during the removal of the copper layer, and damage the low k layer. Electropolishing is a more gentle method than chemical mechanical polishing, and has also been used to remove electrically conductive layers, such as copper. However, electropolishing tends to be unable to break through the oxidation on the surface of the copper layer, and thus is also inadequate for removing the copper layer. In addition, electropolishing also tends to not be able to remove the barrier layer and seed layer that often underlie the copper layer.
[0008] There is a need, therefore, for a new system for use in integrated circuit fabrication, which helps to alleviate one or more of the challenges mentioned above, and enables layers within an integrated circuit to be planarized or otherwise removed without damaging delicate underlying layers.
SUMMARY
[0009] The above and other needs are met by a system for thinning a layer on a substrate without damaging a delicate underlying layer in the substrate. The system includes means for mechanically eroding the layer on the substrate, and means for electropolishing the layer on the substrate.
[0010] In This manner, portions of the layer that cannot be removed by electropolishing can be removed by the mechanical erosion. However, electropolishing can preferentially be used on some portions of the layer so that unnecessary mechanical stresses can be avoided. Thus, the system imparts less mechanical stress to the substrate during the removal of the layer, and the delicate underlying layer receives less damage during the process, and preferably no damage whatsoever.
[0011] In various embodiments, the means for mechanically eroding the layer and the means for electropolishing the layer are configured to operate simultaneously. Preferably, the means for mechanically eroding the layer includes any one or combination of a rotating polishing pad, a rotating brush, and a spray nozzle adapted to direct a spray of a solution towards the layer. The means for electropolishing the layer preferably includes means for establishing a voltage potential through an electrically conductive liquid between the layer on the substrate and the means for mechanically eroding the layer.
[0012] According to another aspect of the invention there is described a system for thinning a layer on a substrate without damaging a delicate underlying layer in the substrate. An electropolishing pad mechanically erodes the layer on the substrate. A power supply establishes a voltage potential through a bath of an electrically conductive liquid between the layer on the substrate and the electropolishing pad.
[0013] In various embodiments of this aspect of the invention, the voltage potential has a range of between about one tenth of one volt and about one hundred volts. In some embodiments the system also includes a brush for mechanically eroding the layer on the substrate, and a spray nozzle adapted to direct a spray of the electrically conductive liquid towards the layer.
[0014] According to another aspect of the invention there is described a method for thinning a layer on a substrate without damaging a delicate underlying layer in the substrate, where a first portion of the layer is mechanically eroded, and a second portion of the layer is electropolished.
[0015] In various embodiments of this aspect of the invention, the first portion of the layer is one or both of an overlying oxidized portion of the layer and an underlying portion of the layer that is formed of a material that cannot be removed by lo electropolishing. The second portion of the layer preferably includes a metal, and is most preferably copper. In one embodiment, the first portion of the layer is electropolished simultaneously with the mechanical erosion, and in another embodiment the second portion of the layer is mechanically eroded simultaneously with the electropolishing. Preferably, the layer includes a first electrically conductive layer, an underlying non electrically conductive barrier layer, and an intervening electrically conductive seed layer. The delicate underlying layer is preferably formed of a low k material. In one embodiment, the first portion of the layer is thinned to a relatively greater extent by mechanical erosion and is thinned to a relatively lesser extent by electropolishing, and the second portion of the layer is thinned to a relatively greater extent by electropolishing and is thinned to a relatively lesser extent by mechanical erosion
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Further advantages of the invention are apparent by reference to the detailed description when considered in conjunction with the figures, which are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein:
[0017] FIG. 1 is a functional block diagram of a chemical mechanical electropolishing system according to a preferred embodiment of the present invention.
[0018] FIG. 2 is a cross sectional view of a portion of an integrated circuit on a substrate, depicting the layers to be removed, and the delicate underlying layer.
[0019] FIG. 3 is a cross sectional view of a portion of an integrated circuit on a substrate, depicting the delicate underlying layer and the structure that is formed after the layers have been removed.
[0020] FIG. 4 is a flow chart of a first embodiment of a method of processing a substrate with a system according to the present invention.
[0021] FIG. 5 is a flow chart of a second embodiment of a method of processing a substrate with a system according to the present invention.
DETAILED DESCRIPTION
[0022] With reference now to FIG. 1 , there is depicted a functional block diagram of a chemical mechanical electropolishing system 10 according to a preferred embodiment of the invention. The system 10 differs in many important aspects from either a traditional chemical mechanical polishing system or an electropolishing system, which differing aspects enable the chemical mechanical electropolishing, or CME, system 10 to thin or remove layers, such as a copper layer, without damaging delicate underlying layers, such as low k layers. The system 10 is also capable of removing additional layers, such as barrier layers and seed layers, which often underlie the main layer to be remove.
[0023] The system 10 is used for processing a substrate 12 on which integrated circuits are formed. The substrate 12 is preferably formed of a semiconducting material, such as of group IV materials like silicon, germanium, or silicon germanium, or group III-V materials such as gallium arsenide. However, in other embodiments the substrate 12 is an insulating substrate, such as alumina, sapphire, or glass. FIG. 2 is a cross sectional view of a portion of an integrated circuit including the substrate 12 . A structure 44 has been formed in a layer 36 of the substrate 12 , which layer 36 may be a low k layer, or a layer of another material which is delicate and easily damaged, as generally described above.
[0024] The layer 36 , in the example depicted in FIG. 2 , is overlaid with a barrier layer 38 , a seed layer 40 , and a conductive layer 42 , such as a copper layer. As can be seen, the barrier layer 38 and the seed layer 40 line the surfaces of the structure 44 , and the conductive layer 42 fills the structure 44 . However, it is desired to remove the layers 38 , 40 , and 42 from the upper surfaces of the layer 36 , to produce the structure 44 as depicted in FIG. 3 . It is this process of removing those upper portions of the layers 38 , 40 , and 42 where prior processing methods have proven to be inadequate, either by not completely removing the layers, or by damaging the delicate layer 36 in the process of such removal. The system 10 as depicted in FIG. 1 is adapted to remove the layers 38 , 40 , and 42 , while reducing and preferably eliminating these problems. FIGS. 2 and 3 depict a single damascene structure. However, it is appreciated that the embodiments of the invention as described herein are equally applicable to dual damascene and other structures.
[0025] The substrate 12 is preferably retained by a carrier 16 , which most preferably provides a rigid support across the entire back surface of the substrate 12 . Thus, the front surface of the substrate 12 , or in other words the surface of the substrate 12 on which the layers 38 , 40 , and 42 are formed as depicted in FIG. 2 , is presented for processing by the system 10 . A method for making an electrical contact with the front surface of the substrate 12 is established but not shown. This contact is necessary for the electropolishing process to occur. The front surface of the substrate 12 is preferably applied against an electropolishing pad 14 during at least a portion of the processing. The electropolishing pad 14 is preferably different in many respects from a standard polishing pad that is used in tradition chemical mechanical polishing.
[0026] For example, the electropolishing pad 14 is preferably formed of a material that is similar to a standard polishing pad, with a conductive filler added. By reducing down force, less friction is developed between the electropolishing pad 14 and the substrate 12 . By reducing the friction between the electropolishing pad 14 and the substrate 12 in this manner, there is less shearing force developed in the delicate layer 36 , which tends to reduce the amount of damage sustained by the layer 36 during processing.
[0027] Most preferably, the substrate 12 is applied against the electropolishing pad 14 with a force that is reduced from that which is traditionally used for chemical mechanical polishing. By reducing the down force applied between the substrate 12 and the electropolishing pad 14 , two benefits are realized. First, the friction is reduced between the substrate 12 and the electropolishing pad 14 , which reduces the shearing force in the layer 36 , and thereby reduces the amount of damage to the layer 36 , as described above. Second, the crushing force applied to the layer 36 is also reduced, which further reduces the amount of damage sustained by the layer 36 during the process. In addition, reducing the amount of down force used during processing of the substrate 12 tends to reduce the amount of dishing and erosion that occurs within the structure 44 .
[0028] In a standard chemical mechanical polishing process, the amount of down force applied between the polishing pad and the substrate is between about four pounds per square inch and about nine pounds per square inch. In the preferred embodiments of the present invention, the down force between the electropolishing pad 14 and the substrate 12 is reduced to be less than about four pounds per square inch, and in a most preferred embodiment is about one and one half pounds per square inch.
[0029] In addition, the electropolishing pad 14 is preferably electrically conductive. In this manner, an electrical potential can be applied through the electropolishing pad 14 , such as by using the electropolishing pad 14 as an electrode, in a manner that is described in more detail hereafter. Further, in one embodiment of the invention, the electropolishing pad 14 is fabricated to have a presented surface area that is smaller than the surface area of the substrate 12 that is presented for processing. One example of this is an electropolishing pad 14 that is circular, and which has a smaller diameter than the generally circular substrate 12 with which it is used. In some embodiments the processing surface area of the electropolishing pad 14 is between about twenty percent and about fifty percent of the processing surface area of the substrate 12 . However, a standard size electropolishing pad 14 could also be used. A typical chemical mechanical polishing pad has a processing surface area that ranges from about twenty-five percent larger than the processed surface area of the substrate 12 , to about fifteen times the surface area of the substrate 12 . Thus, a typical chemical mechanical polishing pad is usually much larger than the surface of the substrate 12 that it is used to process.
[0030] However, by reducing the surface area of the electropolishing pad 14 to be less than the surface area of the substrate 12 which it is used to process, the total amount of friction generated between the electropolishing pad 14 and the substrate 12 is reduced. As described above, this further reduction in the amount of friction generated between the electropolishing pad 14 and the substrate 12 tends to reduce the amount of shearing force that is generated within the layer 36 , and thus tends to reduce the amount of damage that is sustained by the layer 36 during processing in the system 10 .
[0031] The electropolishing pad 14 is preferably mechanically connected to a motion controller 24 , such as by a spindle 22 or other means. In this manner the motion controller 24 enables the electropolishing pad 14 to be moved in a variety of ways. For example, the electropolishing pad 14 can be oscillated, such as in an X or Y direction, or a combination of the two, or along other nonrectilinear axes. Further, the electropolishing pad 14 can be rotated, such as around the spindle 22 . In addition, the entire electropolishing pad 14 can be moved in an orbital motion, such as by translating the spindle 22 around the circumference of a circle, or along an irregular path, or along paths that change according to either a regular or a pseudorandom pattern. The electropolishing pad 14 can also be caused to vibrate, such as with an ultrasonic motion or other high speed motion. In this manner, the electropolishing pad 14 is preferably moved across the surface of the substrate 12 in an even manner, so that the removal of the layers 38 , 40 , and 42 is accomplished uniformly across the surface of the substrate 12 .
[0032] The substrate 12 is also preferably moved relative to the electropolishing pad 14 , such as by engagement with a spindle 18 between the carrier 16 and a motion controller 20 . The substrate 12 can preferably be moved in all of the same ways as those described above in regard to the electropolishing pad 14 . For example, the substrate 12 can preferably be oscillated, such as in an X or Y direction, or a combination of the two, or is along other nonrectilinear axes. Further, the substrate 12 can be rotated, such as around the spindle 18 . In addition, the entire substrate 12 can be moved in an orbital motion, such as by translating the spindle 18 around the circumference of a circle, or along an irregular path, or along paths that change according to either a regular or a pseudorandom pattern. The substrate 12 can also be caused to vibrate, such as with an ultrasonic motion or other high speed motion.
[0033] Most preferably there is some amount of relative motion that is produced by the substrate 12 's motion controller 20 , and some amount of relative motion that is produced by the electropolishing pad 14 's motion controller 24 . However, it is appreciated that in various embodiments it is possible to produce the relative motion using only one of the motion controller 20 and the motion controller 24 , in which case the other motion controller could be omitted from the system 10 design. In a most preferred embodiment, a different motion set is produced by each of the motion controllers 20 and 24 . For example, the motion controller 20 could cause the substrate 12 to rotate around the axis of the spindle 18 or other connection means, while the motional controller 24 causes the electropolishing pad 14 to rotate about the spindle 22 and orbit across the entire surface area of the substrate 12 . Other such combinations of relative motion are also comprehended herein.
[0034] In a most preferred embodiment, at least one component of the relative motion between the substrate 12 and electropolishing pad 14 is at a speed that is dramatically greater from that which is traditionally used for chemical mechanical polishing. One purpose for this is to increase the rate at which material is removed from the surface of the substrate 12 . Without being bound by theory, the rate of material removal is generally proportional to the force exerted or the friction generated between the substrate 12 and electropolishing pad 14 , and the relative speed of motion between the surfaces of the substrate 12 and the electropolishing pad 14 . As the force and friction between the substrate 12 and the electropolishing pad 14 are generally reduced when processed on the system 10 as described herein, the rate of material removal is preferably enhanced or otherwise compensated for by increasing the speed of relative motion. Most preferably, the electropolishing pad 14 is rotated at a speed of between about one hundred rotations per minute and about six hundred rotations per minute. Smaller diameter electropolishing pads 14 are most preferably rotated at the higher speed and larger diameter electropolishing pads 14 are most preferably rotated at the lower speed.
[0035] The substrate 12 and the electropolishing pad 14 are preferably brought into contact in the presence of an abrasive electrolyte 26 that is held by the system 10 , such as within a bath 28 . In other embodiments the abrasive electrolyte 26 may also be introduced by a spray or stream, as described in more detail hereafter. The abrasive electrolyte 26 is different from a standard chemical mechanical polishing solution or rouge in a variety of important respects. For example, the abrasive electrolyte 26 is designed to be both electrically conductive and mechanically abrasive. The abrasive electrolyte 26 may also be chemically abrasive to some degree.
[0036] Although some chemical mechanical polishing solutions may be water based, or based on some other electrically conductive fluid, the abrasive electrolyte 26 is different from these solutions, in that it does not contain impurities which prohibit or otherwise inhibit or degrade an electrolytic oxidation or other removal of the electrically conductive layer 42 , which is most preferably copper. Typical polishing solutions are filled with materials that would tend to plate out or otherwise degrade such a reaction. However, the abrasive electrolyte 26 is preferably free of such materials, and other materials which would tend to oxidize, reduce, or otherwise react at the voltage potentials desired for the oxidation reaction that can be used to help remove the conductive layer 42 .
[0037] Further, the abrasive electrolyte 26 preferably includes abrasive particles. The abrasive particles are preferably inert to the other reactions, both electrical and chemical, which may be occurring within the bath 28 . Most preferably, the abrasive particles have a size of between about fifty nanometers and about two hundred and fifty nanometers in average diameter. Thus, the abrasive particles within the abrasive electrolyte 26 are preferably similar to the abrasive particles found within a slurry used for chemical mechanical polishing.
[0038] Further, in a preferred embodiment, both the substrate 12 and the electropolishing pad 14 are entirely contained within the bath 28 of the abrasive electrolyte 26 . In this manner an electrical potential can preferably be established between the substrate 12 , such as by way of the carrier 16 , and the electropolishing pad 14 , such as by way of the spindle 22 or other backing element. Thus, the substrate 12 and the electropolishing pad 14 are preferably used as electrodes during at least a portion of the processing of the substrate 12 , and the abrasive electrolyte 26 acts as the current carrying medium between the electrode substrate 26 and the electrode electropolishing pad 14 .
[0039] It is appreciated that the electrical potential applied between the substrate 12 and the electropolishing pad 14 can be sustained without there being a complete bath 28 of the abrasive electrolyte 26 . Thus, in other embodiments there is some amount of the abrasive electrolyte 26 introduced between the substrate 12 and the electropolishing pad 14 , but not an amount sufficient to immerse both the substrate 12 and the electropolishing pad 14 . However, in the most preferred embodiment the substrate 12 and the electropolishing pad 14 are both substantially immersed in the abrasive electrolyte 26 during at least a portion of the processing, such as when an electrical potential is applied between the two.
[0040] The entire operation of the system 10 is preferably controlled by a controller 30 , which may be remotely located, but is preferably local to the rest of the system 10 . The controller 30 preferably controls parameters such as, but not limited to, the pressure or down force between the substrate 12 and either the brush 46 or the electropolishing pad 14 , the pressure of the spray 48 , the speed and type of the relative motion between the substrate 12 and any one of the electropolishing pad 14 , the brush 46 , and the spray 48 , the electrical potential between the substrate 12 and either the electropolishing pad 14 or the brush 46 , and which of the electropolishing pad 14 , brush 46 , and spray 48 to use at any given time, if any, and for how long.
[0041] Input such as for the programming of the system 10 is preferably received through an input 32 , which may include such devices as a keyboard, a pointing device such as a mouse or joystick, and a network interface such as can be used for receiving programming and other instructions across a computer network. Most preferably the system 10 also includes a display 34 of some type, upon which information in regard to the programming, processing, and progress of the system 10 can be presented.
[0042] There are many modes in which the system 10 can operate, which modes preferably depend at least in part upon the materials, thicknesses, and other properties of the layers such as 38 , 40 , and 42 that are to be removed from the surface of the substrate 12 , and the nature of the underlying delicate layers, such as 36 . Thus, any specific embodiments described herein are not intended to be limitations on all possible embodiments of the system 10 or its use.
[0043] For example, in the case where the conductive layer 42 is a copper layer, and the underlying layer 36 is a delicate low k layer, there are many challenges to be overcome, as described above. The system 10 overcomes these challenges by way of its unique capabilities. For example, to remove the oxide that tends to form on the surface of the copper layer 42 , and which tends to inhibit the use of electropolishing, the electropolishing pad 14 can be brought into contact with the surface of the substrate 12 for a period of time and with a down force that is just sufficient to remove the oxidation. At that point in time, the down force between the substrate 12 and the electropolishing pad 14 can be reduced, or the contact between the substrate 12 and the electropolishing pad 14 can be removed altogether.
[0044] Then a potential can be applied between the substrate 12 and the electropolishing pad 14 , so that the copper conductive layer 42 is removed by an oxidation or other reaction, such as etching by an acidic abrasive electrolyte. When the copper conductive layer 42 is substantially removed, the electropolishing pad 14 can again be brought in to contact with the substrate 12 , or the down force between the electropolishing pad 14 and the substrate 12 can be increased. In this manner, any remaining portions of the seed layer 40 , and the barrier layer 38 , which is typically formed of a nonconductive material, can be removed, yielding the structure 44 as depicted in FIG. 3 .
[0045] It is appreciated that there are many permutations and combinations of steps such as those described in the specific example above, which can be used to planarize or otherwise remove various layers from the surface of the substrate 12 while reducing or eliminating the damage to the delicate underlying layers, such as layer 36 . The system 10 tends to reduce such damage by reducing the amount of down force that is required for processing, and reducing the friction between the substrate 12 and the electropolishing pad 14 . Further, the system 10 makes use of electrochemical processing to erode the electrically conductive layers, thus further reducing or eliminating the need for contact between the substrate 12 and the electropolishing pad 14 , which further preserves the integrity of the delicate layers such as layer 36 .
[0046] In alternate embodiments of the system 10 , a brush 46 is used either in addition to or in place of the electropolishing pad 14 . For example, the brush 46 may replace the electropolishing pad 14 . Alternately, either the electropolishing pad 14 can be moved away from the substrate 12 to allow room for the brush 46 to be used, or the substrate 12 can be moved away from the electropolishing pad 14 to be adjacent the brush 46 . The brush 46 may be able to better remove specific layers, or better remove layers from different structures of the integrated circuit than the electropolishing pad 14 . For example, a brush 46 , because of its generally reduced amount of surface contact, relative to the electropolishing pad 14 , will tend to induce lesser forces within the substrate 12 . The brush 46 may be one or more of a rolling brush or a rotating brush, or may have some other type of relative motion, produced by a motion controller 50 for example, such as is described above in regard to the motion of the substrate 12 and the electropolishing pad 14 .
[0047] Similarly, a spray 48 may also be used, either in some combination with the electropolishing pad 14 and the brush 46 , or as a replace for one or both of the electropolishing pad 14 and the brush 46 . For example, the electropolishing pad 14 or the brush 46 can be moved away from the substrate 12 to allow room for the spray 48 to be used, or the substrate 12 can be moved away from the electropolishing pad 14 or the brush 46 to be adjacent the spray 48 . The spray 48 preferably sprays the abrasive electrolyte 26 against the surface of the substrate 12 . In preferred embodiments, the level of the bath 28 is reduced when the spray 48 is used, so that the bath 28 of the abrasive electrolyte 26 does not impede the force of the spray 48 .
[0048] The spray 48 may also take one or more of a variety of different forms. For example, the spray 48 may be pulsated, such as with an ultrasonic or other frequency. Further, the spray 48 may be oscillated, spun, or otherwise moved relative to the surface of the substrate 12 , such as with one or more of the motions described above in regard to the substrate 12 and the electropolishing pad 14 . In addition, the spray 48 may be a single jet or multiple jets, and may in different embodiments be directed from a single angle toward the substrate 12 , an adjustable or varying angle, or from a variety of simultaneous angles. The spray 48 may also have some other type of relative motion, produced by a motion controller 52 for example, such as is described above.
[0049] In some embodiments, the use of the spray 48 or the brush 46 may be preferred over the use of the electropolishing pad 14 at different points during the processing of the substrate 12 . For example, the spray 48 or brush 46 could be used during removal of a surface oxidation from the conductive layer 42 , or during the removal of one or both of the seed layer 40 and the barrier layer 38 , or even to increase the rate of material removal during the electropolishing of the conductive layer 42 , in a manner that is more gentle than the application of the electropolishing pad 14 .
[0050] In other embodiments, all three of the electropolishing pad 14 , the brush 46 , and the spray 48 are used during the processing of the substrate 12 . For example, the spray 48 may be used simultaneously with either the electropolishing pad 14 or the brush 46 . Alternately, the electropolishing pad 14 , the brush 46 , and the spray 48 can be separately used at different points in the processing of the substrate 12 , such as when the particular attributes of a given one of the electropolishing pad 14 , the brush 46 , and the spray 48 are most suitable for removal of a given portion of the layers 38 , 40 , and 42 , such as removing an oxide from the surface, removing the conductive layer 42 , removing one or both of the seed layer 40 and the barrier layer 38 , or cleaning off the surface of the layer 36 to ensure than no remaining traces of the removed materials are left behind. In this embodiment, all three of the electropolishing pad 14 , the brush 46 , and the spray 48 are present in the system 10 .
[0051] FIGS. 4 and 5 depict flow charts for two additional possible processing flows 60 and 80 , which are presented by way of example. In FIG. 4 , process 60 starts when a substrate 12 is presented for processing on the system 10 , as given in block 62 . The substrate 12 is initially processed with the electropolishing pad 14 and with the potential applied, as given in block 64 . The substrate 12 may be inspected periodically, as given in block 66 , to determine whether the desired amount of processing has been performed. If not, then processing of the substrate 12 is continued as given in block 64 . If so, then processing of the substrate 12 is completed by one or more of the other methods, such as given in block 68 . The completed substrate 12 is delivered for further processing, as given in block 70 , when all of the processing on system 10 has been completed.
[0052] Similarly, in FIG. 5 , process 80 starts when a substrate 12 is presented for processing on the system 10 , as given in block 82 . The substrate 12 is initially processed with the electrolytic reaction between the substrate 12 and some other electrode, such as either the brush 46 or the electropolishing pad 14 , as given in block 84 , in which the abrasive electrolyte 26 is used as the conducting medium. The substrate 12 may be inspected periodically, as given in block 86 , to determine whether the desired amount of processing has been performed. If not, then processing of the substrate 12 is continued as given in block 84 . If so, then processing of the substrate 12 is completed by one or more of the other methods, such as given in block 88 . The completed substrate 12 is delivered for further processing, as given in block 90 , when all of the processing on system 10 has been completed.
[0053] The foregoing description of preferred embodiments for this invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled. | A system for thinning a layer on a substrate without damaging a delicate underlying layer in the substrate. The system includes means for mechanically eroding the layer on the substrate, and means for electropolishing the layer on the substrate. In this manner, portions of the layer that cannot be removed by electropolishing can be removed by the mechanical erosion. However, electropolishing can preferentially be used on some portions of the layer so that unnecessary mechanical stresses can be avoided. Thus, the system imparts less mechanical stress to the substrate during the removal of the layer, and the delicate underlying layer receives less damage during the process, and preferably no damage whatsoever. |
RELATED APPLICATIONS
This application claims the benefit of to U.S. Provisional Patent No. 60/829,499 filed on Oct. 13, 2006 and entitled ADVANCED LITHIUM BATTERIES BASED ON CERAMIC MEMBRANE ELECTROLYTE.
U.S. GOVERNMENT INTEREST
This invention was made with government support under Contract No. W91 QX-06-C-0092 awarded by the U.S. Army. This invention was also made with government support under Contract No. W9QX-06-C-0058 awarded by the U.S. Army. The government has certain rights in the invention.
FIELD OF THE INVENTION
This invention relates to batteries and more particularly to apparatus and methods for improving the performance of metal-air batteries.
DESCRIPTION OF THE RELATED ART
Our society has come to rely on batteries to power a myriad of devices, including computers, cell phones, portable music players, lighting devices, as well as many other electronic components. Nevertheless, there is an ongoing need for further advances in battery technology. For example, there is currently a tremendous push to develop economical batteries that can be used by automobiles and other vehicles to reduce reliance on fossil fuels and reduce the output of carbon emissions. Furthermore, the “information age” increasingly demands portable energy sources that provide lighter weight, higher energy, longer discharge times, and smaller customized designs. To achieve these advances, technologists continue to work to develop batteries with higher and higher specific energies and energy densities while still providing acceptable safety, power densities, cost, and other needed characteristics.
Metal-air batteries have many applications and advantages that give them a potential edge over many other types of batteries. Theoretically, for example, a lithium-air battery has a higher energy density than virtually all other types of practical battery technologies, including lithium-ion batteries. If lithium-air batteries can be improved significantly, they may provide dramatically improved specific energy, energy density and cost compared to many primary and secondary battery technologies, including lithium-ion secondary batteries. An improved lithium-air battery would be highly beneficial in military, consumer, and many other battery applications.
Advantages of lithium-air batteries include their lower material and manufacturing costs compared to their lithium-ion counterparts. Lithium-air batteries may also be lighter weight, store more energy, have longer discharge times, and have a reduced size compared to conventional lithium-ion batteries. Because of these characteristics, lithium-air batteries (and other metal-air batteries) may have a unique opportunity in many battery markets.
Conventional lithium-air batteries typically include a porous membrane (i.e., a lithium-ion conductive solid polymer electrolyte membrane) interposed between a lithium metal foil anode and a thin carbon composite cathode. The porous membrane permits a non-aqueous electrolyte (e.g., ethylene carbonate, propylene carbonate, etc.) to pass through the membrane while preventing the flow of electrons through the membrane. Oxygen, the electro-active cathode material in the battery, is reduced on the carbon composite cathode during discharge of the battery. Upon discharge, lithium ions and peroxide ions in the battery combine together to generate one or more reaction products (lithium hydroxide, lithium peroxide, etc.) at or near the cathode of the battery.
Nevertheless, conventional lithium-air batteries, like many other battery technologies, are hindered by various limitations. The reaction products (i.e., lithium hydroxide, lithium peroxide, etc.) tend to clog up the pores of the cathode and limit the movement of reactants, significantly limiting the life of the battery.
Unlike the non-aqueous air cathode that is not capable of attaining high current density, an air cathode in communication with an aqueous catholyte is capable of very high current density. For example, Gordon et al., in U.S. Pat. No. 7,259,126 disclosed an excellent oxygen cathode which when exposed to 50% NaOH and oxygen partial pressure of 0.85 atmospheres was able to attain 500 mA/cm 2 with only 350 mV polarization. Likewise, the manufacturer, Electric-Fuel shows on their website polarization data for their air cathode in 8.5M KOH and air where the air cathode had less than 600 mV polarization at 300 mA/cm 2 .
In view of the foregoing, what is needed is an improved metal-air battery that is capable of overcoming one or more of the previously mentioned limitations. Specifically, a membrane is needed that will enable the utilization of an aqueous air cathode that will enable the utilization of a metal-air battery that will reduce or prevent the cathode from becoming clogged with various reaction products.
SUMMARY OF THE INVENTION
The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available metal-air batteries.
Consistent with the foregoing and in accordance with the invention as embodied and broadly described herein, a metal-air battery is disclosed in one embodiment of the invention as including a cathode to reduce oxygen molecules and an anode to oxidize an alkali metal (e.g., Li, Na, or K) contained therein to produce alkali-metal ions. An aqueous catholyte is placed in electrical communication with the cathode. An ion-selective membrane is interposed between the alkali-metal-containing anode and the aqueous catholyte. The ion-selective membrane is designed to be conductive to the alkali-metal ions while being impermeable to the aqueous catholyte.
In selected embodiments, the battery further includes an anolyte interposed between the alkali-metal-containing anode and the ion-selective membrane to conduct the alkali-metal ions from the anode to the ion-selective membrane. In certain embodiments, the aqueous catholyte is a separator material soaked in an aqueous catholyte solution. The aqueous catholyte may be used to store reaction products, such as alkali-metal hydroxides or oxides, and their respective hydrates produced at or near the cathode or in the catholyte.
In certain embodiments, the ion-selective membrane may include a monolith of dense layer, a dense layer sandwiched between porous layers. The dense layer may be fabricated from an ionically conductive material, such as LiSICON, NaSICON, or other suitable ceramic appropriate to the anode material that is also impermeable to the aqueous catholyte. The porous layers, in selected embodiments, may provide structural integrity and rigidity to the dense layer. In certain embodiments, these porous layers may be infiltrated with the anolyte and catholyte, respectively, in order to provide ionic conductivity between the dense layer, and the anolyte and catholyte, respectively.
In selected embodiments, the cathode may be a multi-layer structure. For example, in certain embodiments, the cathode may include a gas-diffusion layer that is hydrophobic but is permeable to oxygen. This may allow oxygen to enter the battery while preventing the aqueous catholyte from leaking out of the battery. A reaction layer may be placed adjacent to the gas-diffusion layer to reduce the oxygen molecules passing through the gas-diffusion layer. In selected embodiments, the reaction layer may contain or be infiltrated with a catalyst to aid in reducing the oxygen. In certain embodiments, this catalyst may include a perovskite-type compound. In other embodiments, this catalyst may include a manganese, cobalt and oxides thereof. In other embodiments, the reaction layer may also include an oxygen evolution catalyst to make the battery rechargeable.
In another aspect of the invention, a method in accordance with the invention includes generating alkali-metal ions at an anode and transporting the alkali-metal ions through an ion-selective membrane that is impermeable to water. The method may further include transporting the alkali-metal ions through an aqueous catholyte solution. These alkali-metal ions may be reacted with oxygen or hydroxyl ions generated at a cathode to produce a reaction product, such as an alkali-metal hydroxide or oxide. These reaction products may then be stored as solutes dissolved in the aqueous catholyte solution and later precipitated over the course of discharge in the catholyte contained between separator and cathode.
In yet another aspect of the invention, a metal-air battery in accordance with the invention includes a cathode to reduce oxygen molecules to produce peroxide or hydroxyl ions and an alkali-metal-containing anode to oxidize the alkali metal contained therein to produce alkali-metal ions. A catholyte solution is placed in electrical communication with the cathode to conduct the alkali-metal ions. An ion-selective membrane is interposed between the alkali-metal containing anode and the catholyte solution. This ion-selective membrane is conductive to the alkali-metal ions while being impermeable to the catholyte solution. The catholyte solution is designed to store, in the form of a dissolved solute, reaction products formed by reacting the peroxide or hydroxyl ions and the alkali-metal ions.
The present invention provides an improved metal-air battery that overcomes various limitations of conventional metal-air batteries. The features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by practice of the invention as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through use of the accompanying drawings in which:
FIG. 1 is a high-level block diagram showing one embodiment of a metal-air battery in accordance with the invention;
FIG. 2 is a high-level block diagram showing one embodiment of a lithium-air battery in accordance with the invention;
FIG. 3 is a high-level block diagram showing one embodiment of a sodium-air battery in accordance with the invention;
FIG. 4 is a high-level block diagram showing one embodiment of a physical implementation of a metal-air battery in accordance with the invention;
FIG. 5 is a top view of one embodiment of a metal-air battery in accordance with the invention in the form of a pouch cell;
FIG. 6 is a side view of the pouch cell illustrated in FIG. 5 ;
FIG. 7 is a cutaway side view of the pouch cell illustrated in FIG. 5 ;
FIG. 8 is a graph showing the operating voltage of a sodium-air battery in accordance with the invention as a function of current density;
FIG. 9 is a graph comparing the energy density of a 100 W-hr battery pack using a foil pouch cell design and a 100 W-hr battery pack using a titanium can cell design; and
DETAILED DESCRIPTION OF THE INVENTION
It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the invention, as represented in the Figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of certain examples of presently contemplated embodiments in accordance with the invention. The presently described embodiments will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.
Referring to FIG. 1 , in general, a metal-air battery 100 in accordance with the invention that overcomes various problems of the prior art may include an anode 102 , a cathode 104 , an electrolyte separator/membrane 106 , and an aqueous catholyte layer 108 interposed between the electrolyte membrane 106 and the cathode 104 . Optionally, the battery 100 may also include a non-aqueous, organic anolyte layer 110 interposed between the anode 102 and the electrolyte membrane 106 . In other embodiments, the anolyte layer 110 may be omitted by placing the anode 102 in direct contact with the electrolyte membrane 106 . Current collectors 111 , 113 , such as metal screens or meshes, may be placed in contact with or be embedded within the anode 102 and cathode 104 , respectively, to conduct electrical current to and from the anode 102 and cathode 104 .
The anode 102 may contain an alkali metal (or alloys or compounds thereof) such as lithium, sodium, potassium, or the like, where it may be oxidized to produce alkali-metal ions upon discharge of the battery 100 . These alkali-metal ions may travel through the electrolyte separator/membrane 106 and the aqueous catholyte layer 108 until they reach the cathode 104 . At or near the cathode 104 , or in the catholyte 108 , the alkali-metal ions may combine with peroxide or hydroxyl ions, generated at the cathode 104 , where they may combine to form one or more reaction products, such as alkali-metal oxides or hydroxides. To prevent these reaction products from precipitating, building up, and clogging the pores of the reaction layer 114 , the aqueous catholyte 108 may be used to store the reaction products as solutes dissolved in the aqueous catholyte 108 . This is one significant advantage of using an aqueous catholyte 108 in combination with the impermeable electrolyte membrane 106 . By contrast, conventional metal-air batteries typically utilize non-aqueous organic electrolytes in which the reaction products are insoluble. Although the much higher solubility of these reaction products in aqueous electrolyte is beneficial over the prior art, there is nothing to prevent allowing the discharge of the anode to take place to the point where hydrates and precipitates of alkali metal oxides and hydroxides form in the catholyte. This may be desirable to achieve higher specific energy and energy density.
In certain embodiments, the cathode 104 may include a gas-diffusion layer 112 and a reaction layer 114 . The gas-diffusion layer 112 may be gas-permeable but hydrophobic. Thus, the gas-diffusion layer 112 may allow oxygen gas to diffuse through the layer 112 in a direction 116 , while preventing the aqueous catholyte 108 from diffusing through the layer 112 in the opposite direction. The reaction layer 114 , on the other hand, may be permeable to the aqueous catholyte 108 (i.e., the layer 114 is hydrophilic) as well as oxygen passing through the gas-diffusion layer 112 . In selected embodiments, the reaction layer 114 may contain or be infiltrated with a catalyst material, such as a perovskite compound, or other material known by those skilled in the art to serve such purpose such as manganese, cobalt and oxides thereof, to aid in reducing the oxygen and/or forming hydroxyl ions. In other embodiments, the reaction layer 114 may also include an oxygen evolution catalyst to make the battery 100 rechargeable.
Because the alkali metal of the anode 102 may react violently with water, and therefore be destroyed by water, the electrolyte membrane 106 may be a structure that is conductive to the alkali-metal ions but impermeable to the water of the catholyte layer 108 . In selected embodiments, the electrolyte membrane 106 may also be a multi-layer structure. For example, in certain embodiments, the electrolyte membrane 106 may include a thin (e.g., 20 to 300 μm) dense inner layer 118 , sandwiched between porous, lower density outer layers 120 . In certain embodiments, the dense layer 118 may form the actual membrane 106 that is ionically conductive but water impermeable. The porous layers 120 , on the other hand, may provide structural strength and rigidity to the dense layer 118 to keep it from breaking or cracking. In certain embodiments, the porous layers 120 may be infiltrated with the aqueous catholyte 108 and non-aqueous anolyte 110 , respectively, to provide ionic conductivity between the dense layer 118 and the catholyte 108 and anolyte 110 respectively.
As mentioned, an alkali metal such as lithium or sodium metal may be used as the anode 102 with a metal current collector 113 , such as a copper mesh or screen, connected to or embedded within the anode 102 . In certain embodiments, the alkali-metal anode 102 may be placed in direct contact with the solid electrolyte membrane 106 . However, this may require verifying that the electrolyte membrane 106 is stable when in contact with the alkali-metal anode 102 .
Alternatively, an ionically conductive liquid electrolyte (i.e., anolyte 110 ) which is conductive to the alkali metal at room temperature may be placed between the alkali metal anode 102 and the solid electrolyte membrane 106 . Such electrolytes may be made, for example, by mixing Lewis acid AlCl 3 with CH 3 SO 2 Cl/LiCl or with Cl 3 P═NPOCl 2 /LiCl, for a lithium-air battery, or with CH 3 SO 2 Cl/NaCl or with Cl 3 P═NPOCl 2 /NaCl for a sodium-air battery. These electrolytes typically have room temperature conductivities of approximately 1.0 to 2.5 Siemens/cm and exhibit electrochemical stability windows of 4.5 to 5.0 volts vs. Li+/Li or Na+/Na respectively. In the case of Li metal, greater than 60 cycles above 80 percent expected capacity has been demonstrated with a Li/LiMn 2 O 4 battery using this electrolyte.
In other embodiments, the anolyte 110 may include organic liquids such as propylene carbonate, dioxolane, ethylene carbonate tetraethyleneglycol dimethylether (Tetraglyme), or room-temperature ionic-liquid, 1-hexyl-3-methylimidazolium bis(perfluoroethylsulfonyl)imide(C 6 mimBeti) or mixtures thereof. The anolyte 110 may also include various lithium or sodium salt(s) and a solvent such as dimethyl carbonate (DMC), diethylcarbonate (DEC), dipropylcarbonate (DPC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, lactones, esters, glymes, sulfoxides, sulfolanes, lithium perchlorate, polyethylene oxide (PEO) or polyacrylnitrile (PAN) with lithium trifluoromethylsulfonate, lithium hexafluorophosphate, or mixtures thereof.
As mentioned, the cathode 104 may include a gas-diffusion layer 112 and a reaction layer 114 . One such cathode 104 , for example, is described in U.S. Pat. No. 7,259,126 entitled “Gas Diffusion Electrode and Catalyst for Electrochemical Oxygen Reduction and Method of Dispersing the Catalyst,” which is herein incorporated by reference. In certain embodiments, the reaction layer 114 may include Teflon, an oxygen reduction perovskite electrocatalyst, and hydrophilic carbon. In certain embodiments, the electrocatalyst of the reaction layer 114 may include a NdCaMnFeO 3 or La 0.6 Ca 0.4 CoO 3 perovskite. These electrocatalysts enable facile one-step reduction of oxygen to hydroxyl ions and exhibit negligible overpotential even at high cathodic current densities. The gas-diffusion layer 112 , on the other hand, may contain a higher amount of Teflon and hydrophobic carbon. In certain embodiments, the gas-diffusion layer 112 may be produced by hot pressing Teflon and hydrophobic carbon powders onto a metal screen, such as a nickel screen.
In certain embodiments, the catholyte layer 108 may include a separator material, such as a cellulose separator material, soaked in an aqueous electrolyte that is conductive to the alkali metal ions produced at the anode 102 . For example, the catholyte layer 108 of a sodium-air battery may include a cellulose separator material soaked in aqueous NaOH. Similarly, the catholyte layer 108 of a lithium-air battery may include a cellulose separator material soaked in aqueous LiOH. In general, the catholyte layer 108 may include absorbent materials soaked in aqueous solutions containing alkali-metal salts such as dissolved alkali-metal hydroxide, chloride, carbonate, perchlorate, hexafluorophosphate, trifluoromethylsulfonate, nitrate, or the like. The catholyte solvent, in selected embodiments, may include aqueous mixtures of ethanol, methanol, propanol, isopropanol, and the like.
As mentioned, the electrolyte membrane 106 may, in certain embodiments, include a NaSICON or LiSICON solid electrolyte membrane 106 (depending on the anode material) that is ionically conductive but impermeable to water. Most types of NaSICON and LiSICON are impermeable to water if they are fabricated with sufficient density. Ideally, the NaSICON or LiSICON is selected to maximize ionic conductivity. In certain embodiments, a suitable NaSICON membrane 106 may be produced by Ceramatec, Inc. of Salt Lake City, Utah. The Ceramatec NaSICON membrane 106 is based on a sodium-metal-phosphate structure (Na 1+x Zr 2 X y (PO 4 ) 3 ) wherein x is between 0 and 3 and X is a proprietary dopant. The Ceramatec NaSICON offers excellent moderate temperature Na + ion conductivity of approximately 9×10 −2 Siemens/cm at 60° C. These NaSICON membranes 106 are excellent sodium-ion conductive and chemically stable and were originally developed for salt splitting and electrodialysis applications.
The NaSICON membrane 106 described above can be formed with a thickness of less than 10 μm using a tape casting approach, which is much thinner than conventional polymer or liquid-filled porous separator membranes. An ultra-thin electrolyte membrane 106 may provide considerable savings in terms of volume and mass of the battery 100 , if of course the reduced thickness is not offset by a need for a thick inactive support material. Another advantage of using this type of membrane 106 is that the materials used to produce solid inorganic electrolytes are generally single ionic conductors. This may reduce or eliminate anionic concentration gradient across the electrolyte membrane 106 and may help to suppress undesirable side reactions or decomposition of the electrolyte. This may also expand the available choices for electrode materials and permit the battery 100 to operate at higher voltages.
A solid electrolyte membrane 106 further has the advantage that it provides a dense, hard surface that can maintain its integrity and inhibit roughening of the microstructure. This may reduce mossy or dendritic deposits that may increase the resistivity of the membrane 106 over time. A NaSICON membrane 106 also is not influenced by scaling or precipitation of divalent, trivalent, tetravalent ions or dissolved solids and does not degrade in the presence of corrosive elements like sodium. The NaSICON membrane 106 can is best operated over pH range from neutral to caustic (e.g., 7 to 14) and selectively transport sodium ions in the presence of other ions at very high electrical efficiency (greater than 95 percent).
Where a lithium ion conductor is required to produce a lithium-air battery, the electrolyte membrane 106 may include a material having the formula Li 1+x M x Ti 2-x (PO 4 ) 3 where 0≦x≦1.5 and where M is Al, Zr, Sn, Hf, Y, or mixtures thereof. In other embodiments, the electrolyte membrane 106 may include a material having the formula Li 1+x M x M″ 2-x (PO 4 ) 3-y (M′O 4 ) y where 0≦x≦1.5; 0≦y≦3; M is Al, Y, Ti, or mixtures thereof; M″ is Zr, Sn, Si, Ti, Hf; and M′ is Si, Nb, or Ge, or mixtures thereof. In other embodiments, an ionically conductive ceramic membrane 106 may include a material having the formula Li 1+x Zr 2 Si x P 3-x O 12 where 0≦x≦3. In yet other embodiments, an ionically conductive ceramic membrane 106 may include a non-stoichiometric lithium-deficient material having the formula (Li 5 RESi 4 O 12 ) 1-δ (RE 2 O 3 2SiO 2 ) δ , where RE is Y, Nd, Dy, Sm, or a mixture thereof and where δ is the measure of deviation from stoichiometry, which may vary between about 0 and 1.
Referring to FIG. 2 , one example of a metal-air battery 100 using lithium as the anode material is illustrated. As shown, lithium may be reduced at the anode 102 to produce lithium ions. These lithium ions may travel through the anolyte 110 , electrolyte membrane 106 , and catholyte 108 , until they reach the cathode 104 . Meanwhile, at the cathode 104 , oxygen may pass through the gas-diffusion layer 112 to the reaction layer 114 , where electrons, oxygen, and water may react to generate peroxide and hydroxyl ions. At the reaction layer 114 , or in the catholyte 108 , the peroxide and hydroxyl ions may react with the lithium ions to form one or more of lithium hydroxide (as illustrated by the chemical reactions on the left) and lithium peroxide (as illustrated by the chemical reactions on the right).
In general, lithium hydroxide may be generated in the lithium-air battery 100 according to the following equations:
Anode/organic anolyte: Li→Li + +e − (1)
Cathode/aqueous catholyte: 0.5H 2 O+0.25O 2 +e − → (2)
Cathode/aqueous catholyte: Li + OH − →LiOH (3)
Similarly, lithium peroxide may be generated in the lithium-air battery 100 according to the following equations:
Anode/organic anolyte: Li→Li + +e − (1)
Cathode/aqueous catholyte: O 2 +2 e − →O 2 2− (2)
Cathode/aqueous catholyte: 2Li + +2O 2 2− →Li 2 O 2 (3)
As mentioned above, because the metal-air battery 100 uses an aqueous catholyte 108 , the lithium hydroxide and lithium peroxide generated according to the above equations may be stored as solutes dissolved in the aqueous catholyte 108 to a large extent before starting to form hydrates.
Referring to FIG. 3 , another example of a metal-air battery 100 using sodium as the anode material is illustrated. As shown, sodium in the anode 102 may be reduced to produce sodium ions. These ions may be conducted through the anolyte 110 , electrolyte membrane 106 , and catholyte 108 , until they reach the cathode 104 . Meanwhile, at the cathode 104 , oxygen may pass through the gas-diffusion layer 112 to the reaction layer 114 , where electrons, oxygen, and water may react to form peroxide and/or hydroxyl ions. At the reaction layer 114 , or in the catholyte 108 , the peroxide and/or hydroxyl ions may react with the sodium ions to form sodium hydroxide.
In general, sodium hydroxide may be generated in the sodium-air battery 100 according to the following equations:
Anode/organic anolyte: Na→Na + +e − (1)
Cathode/aqueous catholyte: 0.5H 2 O+0.25O 2 +e − →OH − (2)
Cathode/aqueous catholyte: Na + +OH − NaOH (3)
The sodium hydroxide generated above may be stored as a solute dissolved in the aqueous catholyte 108 to a large extent prior to forming hydrates.
Although lithium may theoretically produce a battery 100 with significantly higher energy density than sodium, sodium may become a desirable choice because of its higher solubility in water. For example, as indicated by Table I below, lithium may have a free energy of reaction and theoretical voltage that is higher than sodium. Because lithium is much lighter than sodium, lithium by itself has a much higher energy density than sodium (13308 W-hr/kg for lithium compared to 3632 W-hr/kg for sodium, a difference of 9676 W-hr/kg).
Nevertheless, when considering the water that is consumed in the reaction, and then needed to maintain performance of the cathode, the overall performance of the sodium-air battery begins to approach or exceed the performance of the lithium-air battery. For example, once water is taken into account, the specific energy of the sodium-air battery is 2609 W-hr/kg and the specific energy of the lithium-air battery is 5792 W-hr/kg, a difference of 3183 W-hr/kg. When the oxygen consumed by the reaction is considered, the specific energy of the sodium-air battery is 2088 W-hr/kg and the specific energy of the lithium-air battery is 3857 W-hr/kg, a difference of only 1769 W-hr/kg.
The sodium-air battery significantly outperforms the lithium-air battery when the water needed to dissolve the reaction products is taken into account. As shown in Table I, the solubility of sodium hydroxide (i.e., 103) in water is far greater than the solubility of lithium hydroxide (i.e., 12.8). As a result, significantly less water is needed in the aqueous catholyte 108 of the sodium-air battery compared to the lithium-air battery to dissolve the reaction products. When considering the added weight of the water, the energy density of the sodium-air battery (1304 W-hr/kg) is significantly greater than the energy density of the lithium-air battery (455 W-hr/kg).
In practice, both systems can be operated to higher specific energies by allowing some alkali hydroxide hydrate to form which can be tolerated to some extent while still maintaining cathode performance.
TABLE I
Expected Energy Density Calculations for Li/O 2 and Na/O 2 batteries
Characteristics
Li/O 2 Battery
Na/O 2 Battery
Free energy of reaction (ΔGr)
−79.5
−71.8
Number of electrons (n) =
1
1
Voltage (V) =
3.4
3.1
M (W-hr/kg)
13308
3632
M + 0.5H 2 O (W-hr/kg)
5792
2609
M + 0.5H 2 O + 0.25O 2 (W-hr/kg)
3857
2088
Solubility of MOH in water at
12.8
103
20 C (g/100 cc)
M + 0.5H 2 O + 0.25O 2 + Water
438
1172
for Dissolution (W-hr/kg)
M + 0.5H 2 O + Water for Dissolution
455
1304
(W-hr/kg)
Referring to FIG. 4 , in certain embodiments, a physical implementation of a metal-air battery 100 in accordance with the invention may include an electrically conductive housing 400 a , 400 b divided into two electrically isolated halves 400 a , 400 b , such as stainless steel halves 400 a , 400 b . One half 400 b may contain the alkali-metal anode 102 , a current collector 113 (e.g., a copper screen) connected to or embedded within the anode 102 , and the anolyte layer 110 . The other half 400 a may contain the cathode 104 , a current collector 111 (e.g., a nickel screen) connected to or embedded within the cathode 104 , and the catholyte layer 108 . In selected embodiments, the anolyte layer 110 is a separator material, such as a polypropylene non-woven separator, soaked in an anolyte solution. Similarly, the catholyte layer 108 may include a separator soaked in a catholyte solution, such as a cellulose separator soaked in a metal hydroxide solution.
In certain embodiments, the electrolyte membrane 106 may be sandwiched between the two halves 400 a , 400 b to seal and isolate the anolyte and catholyte compartments and to electrically isolate the first half 400 a from the second half 400 b . In certain embodiments, a plastic or elastomeric grommet or other suitable material may be used to seal the two halves 400 a , 400 b to the electrolyte membrane 106 . An electrically insulating clamping device 404 , such as a clip, band, crimp, or the like, may be used to clamp the halves 400 a , 400 b to the membrane layer 106 and hold the halves 400 a , 400 b together. In certain embodiments, openings 402 may be formed in the half 400 a to allow oxygen to flow to the cathode 104 from the surrounding environment.
Referring to FIGS. 5 through 7 , in selected embodiments in accordance with the invention, the battery 100 may be designed in the form of a pouch cell 500 . The pouch cell 500 may achieve higher energy densities than ordinary cells by efficiently using space. The pouch cell 500 may also facilitate stacking and/or wiring the cells 500 in serial or parallel configurations to provide a battery 100 with desired voltage and current characteristics. Although the illustrated pouch cell 500 has a circular shape, the pouch cell 500 may also be designed to have a rectangular shape to maximize space utilization in a rectangular housing.
As shown, in selected embodiments, the pouch cell 500 may include an electrically insulating outer shell or housing 501 a , 501 b such as a polyethylene housing 501 a , 501 b . Like the previous example, the housing 501 a , 501 b may, in selected embodiments, be divided into two halves 501 a , 501 b , with one half 501 a housing the catholyte 108 and the other half 501 b housing the anode 102 and the anolyte layer 110 . The electrolyte membrane 106 , which in this example includes a dense layer 118 sandwiched between two porous layers 120 , may separate the catholyte and anolyte compartments 108 , 110 . In certain embodiments, a series of standoffs 512 may be used to create space between the anode 102 and the membrane 106 to accommodate the anolyte 110 .
In selected embodiments, an electrically insulating support ring 502 , or clamp 502 , such as a polyethylene ring, may be bonded and sealed to an outer circumference of the membrane 106 . This support ring 502 may then be clamped, bonded, and sealed to flanges 504 a , 504 b of the housing 501 a , 501 b to provide an effective seal with the membrane 106 and seal the catholyte and anolyte compartments 108 , 110 . Similarly, in selected embodiments, a support ring 506 , or clamp 506 , such as a polyethylene ring, may be positioned and bonded to an outer circumference of the cathode 104 . This ring 506 may also be bonded to the top of the housing 501 a.
A bottom side of the cathode 104 may communicate with the catholyte 108 through an opening 508 in the housing 501 a and a top side of the cathode 104 may communicate with an oxygen source. Electrically conductive tabs 510 a , 510 b may be electrically connected to current collectors 111 , 113 (not shown) which may be connected to or embedded within the anode 102 and cathode 104 , respectively.
Referring to FIG. 8 , a polarization curve 800 showing the operating voltage of one embodiment of a non-optimized, sodium-air pouch cell, as a function of current density, is illustrated. In this example, the cell utilizes a dense NaSICON electrolyte membrane 118 with a thickness of approximately 380 μm. Ideally, the thickness of the membrane 118 and the volume of the catholyte 108 will be further reduced to decrease the polarization of the cell. This will flatten out the curve 800 and provide improved current/voltage characteristics.
As shown, the polarization curve 800 of the sodium-air cell 100 exhibits a predominantly linear region when the current density is between about 0 and 4 mA/cm 2 , while delivering between about 2.7 and 1.5 volts. The voltage drops off significantly after the current density exceeds 4 mA/cm 2 . Thus, the cell is only viable at current densities that are less than about 4 mA/cm 2 ; however, with further optimization, much higher current densities are expected to be viable and with desirable voltage potential.
Referring to FIG. 9 , a graph comparing the energy density of a 100 W-hr battery pack using a foil pouch cell and a 100 W-hr battery pack using a titanium can cell is illustrated. The energy density of each type of battery is calculated as a function of the number of cells in the battery pack. As shown, the battery pack that uses the pouch cells has a higher energy density than the battery pack that uses the titanium cans for any number of cells in the battery pack. This is due to the pouch cell's more efficient use of space and materials. Nevertheless, the energy density differential may increase significantly as the number of cells in the battery pack increases. For example, the energy density of the battery pack using the pouch cells exceeds the energy density of the battery pack using the titanium cans by only about 20 percent where there are few cells (e.g., 0 to 10 cells). However, the energy density of the battery pack using the pouch cells exceeds the energy density of the battery pack using the titanium cans by approximately 50 percent when the number of cells approaches 50 cells. Thus, it becomes increasingly advantageous to use a foil pouch cell design when multiple cells are wired together.
The present invention may be embodied in other specific forms without departing from its basic principles or essential characteristics. The described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the invention is, therefore, 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. | A metal-air battery is disclosed in one embodiment of the invention as including a cathode to reduce oxygen molecules and an alkali-metal-containing anode to oxidize the alkali metal (e.g., Li, Na, and K) contained therein to produce alkali-metal ions. An aqueous catholyte is placed in ionic communication with the cathode to store reaction products generated by reacting the alkali-metal ions with the oxygen containing anions. These reaction products are stored as solutes dissolved in the aqueous catholyte. An ion-selective membrane is interposed between the alkali-metal containing anode and the aqueous catholyte. The ion-selective membrane is designed to be conductive to the alkali-metal ions while being impermeable to the aqueous catholyte. |
RELATED APPLICATION
Filed on even date herewith is Applicant's application entitled Artificial Middle Expandable Intervertebral Disk Implants, a copy of which is submitted herewith.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an artificial intervertebral prosthesis. More particularly, the present invention relates to a stable, yet flexible, synthetic intervertebral disk prosthesis for insertion into a spine following removal of a natural disk.
2. Description of the Related Art
The spine is a flexible structure comprised of thirty-three vertebrae. The vertebrae are separated and cushioned from each other by fibro-cartilaginous structures called the intervertebral disks. If the spine is injured or becomes diseased, these disks may be surgically removed.
The present treatment of lumbar disk herniation is a compromised functional recovery at best. The disk that has come out of its place has no physiological function and at this time no method is known that will bring back the functional lumbar disk. A disk prosthesis is needed which can be applied to the disk space and provide the cushioning effect for the disk that is expected of the normal disk.
Several unacceptable attempts have been made to solve these problems; such as applying spring loaded disk prosthesis or saline injectable disks with suction cups on the surfaces. The spring loaded disk is so bulky it cannot be inserted into the disk space through the limited opening that is available for this kind of surgery. The saline injectable disk is unstable and the suction cups do not hold it onto the vertebral bodies with their irregular spikey surfaces.
Various methods have been employed to deal with the problems that occur after disk removal. One common procedure has been, after disk removal, to fuse the vertebrae that were previously separated from the disk. Unfortunately, this procedure virtually precludes any degree of spinal flexibility. Similarly, disk removal has been followed by replacement with a disk prosthesis purportedly designed to replicate a natural disk's function. However, although artificial disk prostheses have been developed, none are completely satisfactory.
U.S. Pat. No. 4,309,777 to Patil discloses an artificial disk having a plurality of springs positioned between lower and upper disk portions. In addition, a plurality of spikes extend from the upper and lower portions of the disk to engage the vertebrae. U.S. Pat. No. 4,759,769 to Hedman discloses an artificial spinal disk comprised of upper and lower portions connected by both hinge and spring devices. The Patil and Hedman disks, albeit stable, lack a physiological structure and therefore are not used. U.S. Pat. No. 4,834,757 to Bramtigan discloses vertebral implant plugs on blocks useful in fusing together adjoining vertebral bodies. U.S. Pat. No. 4,863,476 to Sheppard discloses an elongated spinal implant intended for insertion in an intervertebral space. However, the Sheppard implant lacks the advantage of maintaining full contact with the vertebrae. U.S. Pat. No. 4,863,477 to Monson discloses a synthetic intervertebral disk prosthesis composed of a rubber-type material having a hollow interior. The interior may be filled with fluid imparting a certain degree of resiliency to the prosthesis. One disadvantage of the Monson prosthesis, however, is that in the anatomical context of the intervertebral space, its design provides very little stability. Thus, the need for a truly stable yet fully flexible artificial intervertebral disk prosthesis and implant exists and is now disclosed.
SUMMARY OF THE INVENTION
A synthetic intervertebral disk prosthesis or implant is described for implementation into the disk space after surgical removal of a diseased or damaged intervertebral disk. Implants according to this invention have a member for adapting the anatomical region of the disk space and apparatus for expanding the member so it conforms to a portion of that space.
In one embodiment the disk is comprised of a silastic sheath in which a plurality of multisized springs are contained. A plurality of sharp engaging or spiked means extend upwardly from the superior portion and downwardly from the inferior portion of the sheath. After implantation, the silastic sheath is filled with a volume of fluid to create resiliency and induce flexibility.
The present invention recognizes and addresses the previously-mentioned long-felt needs and provides a satisfactory meeting of those needs in its various possible embodiments. To one of skill in this art who has the benefits of this invention's teachings and disclosures, other and further objects and advantages will be clear, as well as others inherent therein, from the following description of presently-preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. Although these descriptions are detailed to insure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to claim an invention no matter how others may later disguise it by variations in form or additions of further improvements.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above-recited features, advantages and objects of the invention, as well as others which will become clear, are attained and can be understood in detail, more particular description of the invention briefly summarized above may be had by reference to certain embodiments thereof which are illustrated in the appended drawings, which drawings form a part of this specification. It is to be noted, however, that the appended drawings illustrate preferred embodiments of the invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective equivalent embodiments.
In the accompanying drawings:
FIG. 1 is a top plan view of a synthetic intervertebral disk prosthesis of the present invention.
FIG. 2 is a cross sectional view of the device of FIG. 1 in coronal plane.
FIG. 3 is cross sectional view of the device of FIG. 1 in the sagittal plane.
FIG. 4 depicts a side elevational view of the present invention in its pre-expansion form ready for insertion into the disk space.
DETAILED DESCRIPTION OF THE INVENTION
The disk prosthesis and implants of the present invention can be understood with reference to FIGS. 1 to 4, in which like numerals represent like parts.
FIG. 1 depicts a typical spring loaded, middle expandable total disk prosthesis 2 of the invention. Disk prosthesis 2 is comprised of a strong thin elastic bag 4. Generally, the outer edge 3 of the fully formed disk 2 will be about one centimeter in thickness and a center region 7 of the disk will be about 1.75 centimeters in thickness. The disk prosthesis 2 tapers from center region 7 to the outer region 6 in all directions radially from the center region 7. The interior surface and superior surface of the disk prosthesis 2 are provided with a plurality of spikes 8 extending upwardly from the superior surfaces and downwardly from the inferior surface 9 therefrom for engagement of the vertebra. The disk prosthesis 2 is expandable by injecting a liquid or gas substance through a port 10. Suitable substances for injection include, but are not limited to, saline, mineral oil, air, and oxygen. The disk prosthesis 2 will expand like a balloon to its full dimensions and tightly fit into the disk space.
FIG. 2, a cross-sectional view of disk prosthesis 2, shows that the disk prosthesis 2 of the present invention contains a plurality of compression springs 12 extending vertically between the superior 5 and inferior 9 surfaces, at various strengths and lengths to yieldably urge the superior 5 and inferior 9 surfaces away from each other.
FIG. 4 depicts a side elevational view of the compressed form of the present invention. When disk prosthesis 2 is empty, it contains only the plurality of springs 12 within an elastic bag 4. This can be rolled up into a tight bundle so that the whole prosthesis 2 has a rectangular shape. Disk prosthesis 2 of FIG. 4 shows injection port 10 used for injection of liquids and/or gases. Suitable liquids and gases include saline, air, and oxygen or any other liquid or gas which causes expansion of the prosthesis. Bands 14 of reinforced silastic encircle disk prosthesis 2 so as to maintain disk prosthesis 2 in a shape and size suitable for insertion through a one square centimeter opening into the disk space. In addition, bands 14 hold down strings 16. Strings 16 are pulled after insertion of disk prosthesis 2 into the disk space thus breaking bands 14 and allowing initial expansion of disk prosthesis 2 caused by the release of springs 12. Subsequently, a suitable liquid and/or gas is injected through port 10 causing complete expansion of disk prosthesis 2 for a very tight fit in the disk space. In addition, the spikes 8 hold disk prosthesis 2 into the vertebral bodies of the spine thus inhibiting or preventing movement of the disk within the intervertebral disk space. As disk prosthesis 2 is expanded in the center region 7 there is no risk of extrusion out into the intervertebral disk space.
The surgical introduction of disk prosthesis 2 can provide increased or maximum stability. Different sizes of the disk prosthesis of the present invention may be provided for insertion into lumbar, thoracic and cervical disks. The artificial disk prosthesis may be composed of any biologically compatible material, e.g. rubber, silicone-rubber compounds, plastic, or plastic-rubber compounds.
The same plug in smaller dimensions can be used in the thoracic and cervical levels where indicated. In the neck this can be used following anterior cervical diskectomy without the risk of the plug migrating anteriorly or posteriorly.
Generally, the height of the substantially oval disk prosthesis of the present invention is from about 1 to about 1.5 cm at the periphery and from about 1.50 to about 2.5 cm in the center region. Generally, the diameter of the disk prosthesis of the present invention is from 4 to about 6 cm from side to side at its longest diameter and from about 3 to about 4 cm from side to side in the perpendicular direction.
In conclusion, therefore, it is seen that the present invention and the embodiments disclosed herein are well adapted to carry out the objectives and obtain the ends set forth at the outset. Certain changes can be made in the method and apparatus without departing from the spirit and the scope of this invention. It is realized that changes are possible and it is further intended that each element or step recited in any of the following claims is to be understood as referring to all equivalent elements or steps for accomplishing substantially the same results in substantially the same or equivalent manner. It is intended to confer the invention broadly in whatever form its principles may be utilized. The present invention is, therefore, well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as others inherent therein. | An artificial disk prosthesis and methods for implanting it, the prosthesis. In one embodiment having a member for adapting in size and shape to an anatomical space between vertebrae and apparatus for expanding the member to conform to the space. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to transdermal medication fluoride drug product for treatment or prevention of osteoporosis or other bone disease. More particularly, this invention relates to the use of sodium monofluorophosphate, alone or in combination with another fluorine compound, and, optionally, with an estrogen-containing substance and, if desired, a calcium containing substance, in a transdermal patch suitable for use in the treatment and prevention of osteoporosis, alveolar bone loss or other bone diseases where systemic fluoride ion is efficacious and further treating hormonal imbalance and enhancing utilization of the fluoride ion by introduction of estrogen.
2. Description of the Prior Art
Fluoride stimulates the activity of bone-forming cells and, together with calcium and phosphate, the two major mineral components of bone is also stored in the bone structure. Fluoride seems to directly stimulate the proliferation of osteoblasts resulting in an increase in bone formation.
U.S. Pat. No. 3,287,219 discloses the oral administration of sodium fluoride to promote bone healing.
The role of fluoride in strengthening the teeth and in imparting acid resistance and preventing caries in dental treatment is well documented. The use of sodium fluoride tablets and liquids for infants and young children in areas where the drinking water is not or is only insufficiently fluoridated is well known. For this purpose, fluoride ion from NaF is administered in dosages of about 0.25 to about 1 mg per day. Representative patents in this area include U.S. Pat. Nos. 3,306,824, 4,265,877 and 4,397,837 (toothpaste). The use of sodium monofluorophosphate (MFP) in dental products, particularly toothpaste products, as an anticaries fluoride additive is also well known and is mentioned in U.S. Pat. No. 4,397,837, cited above. The MFP is slowly metabolized by an intestinal enzyme, MFPase or alkaline phosphatase into free fluoride ion which, in turn, is absorbed into the blood stream, some of the MFP being directly absorbed in the liver and converted therein to F ion.
More recently, the use of NaF or MFP for the treatment of bone disease to promote bone formation and strengthen bone has received wide attention. In fact, although not yet approved for use in the United States, both NaF and MFP products for the treatment and prevention of osteoporosis are available in Europe. Thus, Flurexal® is an enteric coated tablet containing 22 mg sodium fluoride (10 mgF) sold by Zyma SA Nylon Suisse; Tridin® is a chewable tablet containing 38 mg sodium monofluorophosphate (5 mg F), 500 mg calcium gluconate monohydrate, 500 mg calcium citrate tetrahydrate, 200 mg carboxymethyl cellulose, available from Opfermann Arzneimittel GmbH.
According to the directions for use provided with the medications, Flurexal® should be taken three times each day, while Tridin® should be taken one to two tablets three times a day for treatment or one tablet three times a day for prevention of steriod-osteoporosis. In general, the typical recommended dosage for F ion is in the order of from about 20 to 50 mg per day for a human adult.
The literature provided with Tridin® states that gastric and intestinal irritation is seldom observed. To the same effect, Yngve Ericsson, "Monofluorophosphate Physiology: General Considerations," Caries Res. 17 (Suppl. 1), pages 46-55 (1983), reported that "neither in patients nor in numerous experiments with laboratory workers has any subjective discomfort been recorded with doses up to 30 mg F as MFP." However, in one of the present inventors' own clinical studies and patient evaluations, the occurrence of gastric and intestinal distress was observed in a significant number of cases.
Attempts to solve the adverse side effects of gastrointestinal (GI) tract symptoms by minimizing the availability of F ion in the stomach by providing NaF in a sustained release form have only been partially effective in avoiding GI irritation. More particularly, it has been observed that, while slow release sodium fluoride is well tolerated by approximately 70% of patients, there is adverse gastrointestinal effects in the other approximate 30% of patients.
The use of MFP in slow release form is described in recently issued U.S. Pat. Nos. 4,859,467 and 4,861,590. Transdermal patches have become well known for dosage of medications, such as nitroglycerin for treatment of angina, scopolamine for treatment of motion sickness and numerous others. To this end, various transdermal enhancers have been used for facilitating the delivery of the medication through the skin of the user.
SUMMARY OF THE INVENTION
The present invention relates to a transdermal patch for application of a fluoride medication and, optionally, of estrogen to the patient with or without calcium and/or phosphate-containing substances. To this end, on a thin fluid impervious bottom sheet, a base sheet for strengthening the patch is bonded. The periphery of the bottom sheet opposite the base sheet may be coated with a pressure-sensitive adhesive or adhesion may be attained from the medication, which includes one or more fluoride containing substances and, optionally, estrogen, calcium and phosphate-containing substances, as well as a transdermal enhancer.
DETAILED DESCRIPTION OF THE INVENTION
Osteoporosis can be broadly defined as increasing weakness and fragility of the bones. It most frequently occurs in elderly, post-menopausal women and in elderly (presenile or senile) men, but also occurs in idiophathic forms. Osteoporosis can also occur in connection with, i.e. as an undesirable side effect of, corticoid treatment (steriod-osteoporosis). Certain localized forms of bone disease may also be associated with a general weakness and fragility of the bone structure due to insufficient new bone formation. Therapeutic indications includes any bone wasting disease, genetic, such as osteogenesis imperfecta, or acquired, such as renal bone disease.
In women undergoing menopause and post-menopausal females there is often present an hormonal imbalance heretofore treated by oral dosages of estrogen or by injection of estrogen.
One of the effects of advanced periodontal disease is the loss of alveolar bone (i.e. that portion of the jaw bones that support the teeth) mass, which eventually causes loosening and loss of teeth. Alveolar bone loss may also occur after tooth extractions and, in some cases, after the insertion of dental implants.
Bone is composed of an organic phase, collagen and an inorganic crystalline phase of calcium phosphate, or more specifically, hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 . Fluoride plays an important role in the prevention of bone loss by stimulating the formation of less soluble fluorapatite Ca 10 (PO 4 ) 6 F 2 . Therefore, in osteoporosis, alveolar bone loss and other bone diseases associated with general weakening or loss of the bone tissue, or in cases where the normal dietary intake of calcium is insufficient, a dietary supplement to supply additional calcium is usually appropriate. The addition to the calcium supplement of, or the separate administration of, a source of fluoride ion will, according to recent scientific research, greatly enhance the reversal of bone loss, the fluoride stimulating new bone formation and the calcium being an indispensable building block for bone tissue.
Sodium fluoride and sodium monofluorophosphate can each be used to provide the fluoride ion to be absorbed into the blood for eventual skeletal uptake. Sodium fluoride, NaF, has the advantage that it has a higher F content than sodium monofluorophosphate, MFP. NaF is also more rapidly absorbed, at least in the first few hours, into the blood. However, NaF has higher acute toxicity than MFP and causes stomach irritation in a much higher percentage of patients than does MFP. Moreover, and perhaps most important, is the fact that NaF is incompatible with ionizable calcium compounds, forming poorly soluble CaF 2 , thereby depleting the availability of the F ion to a large extent and of the Ca ion to a smaller extent (based on the much greater total quantity of calcium present in the patient's system). On the other hand, MFP is compatible with ionizable calcium compounds since Ca(MFP) is about twenty times more soluble than CaF 2 .
Unfortunately, when ingested orally in the recommended dosages, typically about 20 to 50 mg F per day for human adults, MFP, although not as pronounced as NaF, also causes stomach irritation.
In accordance with the present invention, it has been found that by incorporating the MFP alone or in combination with a small amount of sodium fluoride, the occurrence of GI irritation can be avoided when using the transdermal patch according to the present invention.
According to the present invention, a transdermal patch is employed which employs a bottom thin plastic sheet of, for example, polyethylene or polypropylene overlying which is a strengthening base sheet bonded at its periphery to the bottom sheet. Suitable base sheets include particularly those of a non-woven hydrophobic fiber, such as nylon, which is substantially non-tearable. Other hydrophobic fibers, such as polyethylene or polypropylene fibers, can be employed which are effective in strengthening the transdermal patch though not as strong as a heat bonded non-woven nylon.
The patch is preferably circular in shape and is formed by stamping simultaneously under heated conditions the bottom and base sheets to bond the peripheries of the two sheets together. This is accomplished by the suitable application of heat during stamping.
The bottom sheet on the side not bonded to the base sheet along the peripheral edges of the patch is coated with a pressure-sensitive adhesive to ensure at least initial attachment of the transdermal patch to the skin of the wearer. When the patch is to be applied to the thighs of the patient, the patches are preferably round in configuration. Such circular shape is the most efficient because of presenting less likelihood of peeling as would occur if sharper curvatures were used, as in oval shaped or corners to be found in other geometrical shapes.
The medication to be applied by the patch includes monofluorophosphate with or without castor oil or glycerine and any of the well-known transdermal enhancers such as N-dodecyl pyrrolidone, N-tetradecyl pyrrolidone (and corresponding caprolactams), as well as longer chain substituted dioxolanes and dioxanes.
Preferably, the transdermal enhancer to be used is N-dodecyl pyrrolidone. In addition to the monofluorophosphate, from five to twenty percent, preferably five to ten percent, of NaF by weight, compared to the amount of monofluorophosphate, may be employed.
A calcium containing substance, as well as a phosphate containing substance, may be employed, as well as an estrogen containing substance.
In use the transdermal patch is employed by application on the skin of the patient in a location as prescribed by the physician.
Typical formulations for use in a transdermal patch according to the invention are shown immediately below:
EXAMPLE 1
______________________________________Ingredient Amount (milligrams)______________________________________Monofluorophosphate 200.0Transdermal enhancer 100.0Total Content weight 300.0 mg______________________________________
The transdermal enhancer is preferably N-dodecyl pyrrolidone for all Examples.
EXAMPLE 2
______________________________________Ingredient Amount (milligrams)______________________________________Sodium monofluorophosphate 200.0Conjugated Estrogens USP .5Castor Oil 5.0Transdermal enhancer 94.5Total Content weight 300.0 mg______________________________________
The amount of conjugated estrogens USP may vary from 0.3 to 0.625 mg. The transdermal enhancer with the monofluorophosphate produces an adhesive-like composition with the castor oil.
EXAMPLE 3
In lieu of conjugated estrogens USP, esterified estrogens USP in an amount varying from 0.2 to 0.4 mg may be employed, preferably 0.3 mg. As a result, not only is hormonal imbalance treated, but the estrogen has the additional effect of enhancing utilization of the fluoride ion.
EXAMPLE 4
In lieu of the conjugated estrogens USP in Example 2, there is utilized estradiol and derivatives USP in an amount varying from 0.02 to 0.2 mg, preferably 0.1 mg. As a result, not only is hormonal imbalance treated, but the estrogen has the additional effect of enhancing utilization of the fluoride ion.
These formulations provide F ion and estrogen and are designed to release the fluoride ion and estrogen in the bloodstream slowly.
The use of sodium monofluorophosphate as the sole fluoride source is preferred. However, if desired, the formulations can include small amounts of NaF or other fluoride compound. Thus, NaF in amounts from five to ten percent, up to twenty percent, by weight based on the total weight of NaF+MFP can be added.
In addition to each of the above Examples, other active ingredients may be included which are as follows:
Calcitriol, (1,25-Dihydroxyvitamin D 3 form.
Phosphates, Potassium and Sodium Mono- and Dibasic Phosphates.
The transdermal patch is packaged individually in a fluid proof package after a peelable fluid proof cover sheet of larger size than the patch is applied overlying the medication. | A transdermal fluoride medication for providing fluoride ion for the prevention and treatment of bone loss disease, which may have an estrogen-containing substance for not only treating hormonal imbalance but to obtain more advantageous use of the fluoride ion within the body. A transdermal enhancer is present. The preferred form is a transdermal patch containing sodium monofluorophosphate and further optionally including an estrogen-containing substance and a transdermal enhancer, which is adhesively attached on the skin of the patient for slow release of fluoride ion and, optionally, estrogen to the bloodstream of the patient. Up to ten percent of sodium fluoride and/or calcium can be added. |
This application claims the benefit, under 35 U.S.C. § 365 of
International Application PCT/CN2007/000624, filed Feb. 27, 2007, which was published in accordance with PCT Article 21(2) on Sep. 4, 2008 in English.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the technical field of wireless local area networking (WLAN) and, more particularly, to a method and apparatus for power saving in a WLAN.
2. Description of Related Art
With the proliferation of portable computing and mobile technology, energy conservation has become an important issue and receives more and more attention. To make the best use of battery resources and prolong a device's battery life, a power saving mechanism is proposed within the IEEE 802.11 standards (IEEE 802.11 standard for Information Technology—Telecommunications and Information Exchange between Systems Local and Metropolitan Area Networks Specific Requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. ANSI/IEEE Std. 802.11, ISO/IEC 8802-11. First Ed. (1999)). As specified in the standard, an IEEE 802.11 based wireless adapter, or station, can be in one of two states at any time, awake or sleep. The sleep state usually consumes an order of magnitude less power than the awake state. Therefore, the task of the power saving mechanism is to maximize time spent in the sleep state and minimize time spent in the awake state, while not degrading the networking performance of the device.
FIG. 5 shows a simplified block diagram useful in explaining both the background and an embodied configuration of the present invention and includes a basic service set (BSS) ( 50 ) with access point (AP) ( 31 ) and multiple wireless stations ( 32 - 1 to 32 - n ). Each of the stations has the two states or power modes as defined for a typical IEEE 802.11 wireless adapter. The modes are defined as constant active mode (CAM) and power saving mode (PSM). In the CAM, the wireless adapter remains in an awake state during its entire working time, monitoring the wireless channel and ready to receive or transmit frames at any time. An AP ( 31 ) delivers frames destined for a station in CAM without buffering. Obviously the CAM causes substantial power consumption for a mobile station which has limited battery life.
A station in PSM (any of stations 32 ) cooperates with its associated AP ( 31 ) to achieve power savings. Within the IEEE 802.11 standard, the general idea is for the AP to buffer frames for stations in PSM and to synchronize these stations to wake up at the same time. At the wakeup time, there starts a window where the AP announces its buffer status to the associated mobile stations by using a beacon. The AP periodically transmits the beacon and a mobile station in PSM shall power up to listen to the beacon to check whether there are frames buffered in the AP. The stations determine whether there are buffered frames by analyzing bitmap information in a traffic indication map (TIM) element contained in the beacon. The TIM structure is depicted in FIG. 1 . If there is buffered data, the receiver stays awake until the data has been delivered. A beacon may indicate whether there are unicast frames or broadcast/multicast (B/M) frames buffered at the AP. A station enters into the PSM state only after ensuring that no unicast frames destined for it or B/M frames for a group are pending at the AP, otherwise it shall stay awake to receive frames.
In the unicast case, the AP buffers incoming frames destined to a power saving (PS) station, announce this event through the TIM in a beacon frame, and then these buffered frames are retrieved by the PS station through PS-Poll requests. In the B/M case, the AP buffers all incoming broadcast/multicast frames if any client in the BSS is in PSM and sends them out without polling after a beacon with a delivery traffic indication message (DTIM) has been transmitted. A DTIM is a special TIM. In both cases, the PS station stays in the awake state unless it is explicitly notified that the buffered frames, destined for it or for a group, are swept out.
The TIM element of the beacon frame plays a key role in the overall procedure. It provides a one to one mapping between bits and mobile stations through the association identifiers (AIDs). AIDs are assigned to each client within a basic service set (BSS) during the association procedure. When a client joins a BSS the AP gives the client an AID. In addition, the AID is used to determine the location of a stations bit in the TIM. In other words, each station associated with the AP is assigned one bit in the bitmap of a TIM with the position of the bit being related to the AID the station was assigned. The bit number N corresponds with the AID N in the TIM bitmap. If the bit N is set in the TIM of a beacon the existence of buffered unicast frames for the station AID N is indicated.
With reference to FIG. 1 , each field of the TIM structure is described as follows: Element ID (one byte) is an identification of this length-variable element in the beacon frame, and its value 5 indicates that this is a traffic indication map (TIM). The Length field (one byte) gives the total length of the information field, which consists of the following four fields:
1) DTIM (delivery traffic indication message) count (one byte) defines the number of beacons that should be sent out before the next DTIM appears. This value decreases with each beacon, and after reaching zero it returns to the initial value; zero being an indicator of a DTIM. Thus DTIM is a special TIM, with its DTIM count field equal to zero. 2) DTIM period represents the number of beacon intervals between successive DTIMs. Note that the DTIM count should cycle through from this value to 0 and return to this value after reaching 0. 3) Bitmap Control field (one byte) contains two subfields. Bit 0 is used for the traffic indicator bit of association ID 0 (AID 0 ), which is reserved for B/M traffic. This bit should be set to 1 if there is one or more B/M frames buffered at an AP for any stations in this BSS. The other 7 bits are used for the offset of the virtual bitmap. The offset infers the exact part of the virtual bitmap that has been transmitted. 4) Partial virtual bitmap (251 bytes) is an important feature of the TIM or DTIM element. Each bit of the virtual bitmap matches a mobile station that associated with the AP, and its association ID (AID) is the position of the corresponding bit in the whole bitmap. Theoretically, an AP can support as many as 2008 stations in one BSS. Whenever a frame destined for a station in power saving mode arrives, it should be buffered and its corresponding bit in the virtual bitmap be set in the TIM of the beacon, calling for the corresponding station to fetch the frames at the AP afterwards.
A special bit, corresponding to AID 0 , is reserved for B/M frames. As shown in FIG. 1 , the bitmap control bit 0 corresponds to AID 0 . If there is at least one associated station working in PSM, then any incoming B/M frames at the AP causes this bit to be set to 1 and the B/M frames buffered. Thus, while the TIM can uniquely identify a station with buffered unicast frames at the AP; the one bit, AID 0 , can only indicate the existence of B/M frames without identifying the group or specific stations having buffered B/M frames. A message with an AID of 0 requires all PSM stations to stay awake to receive broadcast frames in order to determine whether they belong to the group in which B/M frames are buffered.
Generally the PSM outperforms the CAM in terms of power consumption, at the cost of networking performance, such as delay and throughput. However, in practice the current PSM is still not efficient enough to achieve power conservation. For example:
1) Though a station can be informed of the existence of buffered unicast frames for it at the AP through a TIM within a beacon frame, it is impossible, as implied by the current mechanism, for the station to control the timing of the starting and ending of the transmission of the buffered frames; thus, the station has to stay awake for an unpredictable period, until the procedure concludes. The length of the awake period within a beacon interval depends on the number and size of a station's buffered frames at the AP, but also is greatly affected by other stations retrieval of buffered frames. The progress of transmitting the buffered frames for one station can be put off for a long time because of another station's behavior, causing substantial power consumption by the station.
2) According to the 802.11 standard, once a DTIM has been sent out with a beacon, the AP can sweep out all the buffered B/M frames thereafter. This behavior may have a great impact on another station's networking performance, especially for unicast applications, as the intrinsic preemptive characteristic of broadcasting/multicasting can lead to the non-availability of the wireless medium for other stations. A more flexible scheme should be adopted for the transmission of B/M frames.
3) The current mechanism uses one bit to indicate the existence of buffered B/M frames at the AP. Therefore, the current mechanism does not differentiate between multicast frames and broadcast frames, and moreover, multicast frames belonging to different multicast groups are treated as the same. This coarse granularity makes the scheme work inefficiently in multicasting environments. The major deficiency lies in that a mobile station has to stay in the active state whenever there are multicasting frames transmitting at the AP, even if these frames are destined to other multicast groups than the group this station belongs to, or a worse case that this station does not join any multicast group at all. The energy used to scout multicast traffic that will not be received by a station is an unnecessary waste.
What is needed is an arrangement and method that addresses the above-mentioned problems
SUMMARY OF THE INVENTION
In an embodiment of the present invention a method for transmitting data in a wireless local area network is described. The method includes buffering, at an access point, frames including data to be transmitted to stations capable of operating in a power-saving state. Prior to sending a beacon frame, the access point divides an interval between beacon frames into a number of time slices. The access point transmits the beacon frame including information about a time slice when buffered frames destined for particular stations will be sent.
In a further embodiment a method for use in a node in a 802.11 wireless local area network, the network including an access point and at least one station. The method includes formatting data into a control frame for use in the wireless local area network, the frame including an indication, for each station associated with the wireless local area network, whether frames are buffered awaiting transmission to each respective station, a number of time intervals between control frames, and at which time interval the transmission of the buffered frames will begin for each station having buffered frames awaiting transmission. The frame is then transmitted.
In another embodiment an access point in a wireless local area network, which periodically transmits a beacon frame is described. The access point includes a transmitter for transmitting data, including the beacon frame, through the wireless local area network to plural stations, a memory to buffer frames awaiting transmission to the plural stations, which are capable of operating in a power-saving state, and a processor dividing an interval between beacon frames into a number of time slices, and transmitting information about a time slice when buffered frames for a respective station will be sent.
In another embodiment a method of receiving data in a wireless local area network is described. The method includes receiving a beacon frame having information regarding time slices indicating when data associated with a particular station will be transmitted; and determining whether an interval between a current beacon frame and a subsequent beacon frame includes data to be received by the particular station, if so, determining a time slice within the interval that includes the data to be received.
In another embodiment a station in a wireless local area network is described. The station includes a receiver receiving a beacon frame having information regarding time slices indicating when data associated with a particular station will be transmitted; and a processor determining whether an interval between a current beacon frame and a subsequent beacon frame includes data to be received by the particular station, if so, determining a time slice within the interval that includes the data to be received.
These and other aspects, features and advantages of the present invention will become apparent from the following description of non-limiting exemplary embodiments, which is to be read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 : a diagram of a TIM structure of a Beacon of the IEEE 802.11 standard;
FIG. 2( a ): an exemplary embodiment of a Beacon with a newly designed TIM structure in accordance with the present invention;
FIG. 2( b ): an exemplary embodiment of a frame structure of the present invention in accordance with the present invention;
FIG. 3 : an exemplary embodiment of a multicast association and disassociation;
FIG. 4 : an exemplary diagram illustrating a service period in accordance with the present invention;
FIG. 5 : an embodied configuration of a wireless network infrastructure in accordance with the present invention;
FIG. 6 : an embodied configuration of an access point in accordance with the present invention.
DETAILED DESCRIPTION
The original TIM structure in the IEEE 802.11 standard, as described above, does not carry sufficient information for supporting a more complicated power saving scheme. An embodiment of the invention provides a TIM structure that is able to support time slicing operations for power management and addresses the problems mentioned above.
FIG. 2( a ) shows an exemplary embodiment of a TIM structure of a Beacon frame. Compared with the original TIM structure, two fields, slicing control field and slicing map field, are added at the end of the partial virtual bitmap (PVB) for supporting time slicing. In addition, the significance of the PVB bits changes within this new structure. These amendments and modifications are detailed as follows.
1) Slicing Control Field:
The slicing control field, as shown in FIG. 2( a ), includes 1 byte of data. This field regulates the number of bits used for each slicing index (SI) in the slicing map field. For example if the byte of data in the slicing control filed defines a number n, then each SI will have n bits. A slicing index (SI) defines the relative starting position of the time slices assigned to a destination corresponding to a specific MAC address. In this disclosure, the term destination is used instead of client or station, as during the procedure of resource allocation, e.g. AID or time slices, group MAC addresses are treated as the same as the unicast MAC addresses.
Once the number of bits for each SI is set in the slicing control field, the AP can determine how many time slices the beacon period should be divided into. The number of time slices shall equal the maximal possible value of the SI, that is, for a n-bit-wide SI, a total of 2 n −1 slices shall be derived. For example, if the slicing control field is set to 5, then the beacon period should be divided into 2 5 −1=31 consecutive time slices. For a beacon period of 100 ms, each time slice lasts about 100/31=3.226 ms.
As the slicing control field is constrained to 8 bits, the maximal number of bits for a SI can be set to 2 8 −1=255; therefore, the maximum number of bits in an SI is 255 where the beacon period could be divided into 2 255 −1 consecutive time slices. Various factors and variables are evaluated as desired to implement an “optimal” slice control. These variables may include the number of slices desired, a desired granularity, and the number of different stations having buffered frames. In addition the higher the value of the slicing control field means finer granularity of the time divisions and thus less power consumption, however this comes at the cost of a longer slicing map (SI), which results in more overhead of the beacon frame. Hence setting this field is a trade-off between power performance and increasing the overhead of the beacon frames. In a preferred embodiment, the slicing control field value should not exceed 10, as 2 10 −1=1023, that is, using 1023 bits to indicate the position of the assigned time slices, which is a large overhead for the beacon frames.
2) Slicing Map Field:
The slicing map field, as shown in FIG. 2( a ) gives the exact starting position of the assigned time slices for each destination. The position is expressed as slicing index (SI), whose value ranges from 1 to 2 n −1, n being the value set in the slicing control field. The first SI always corresponds to AID 0 . If the first SI is set to 0, this indicates that there is no broadcast frames buffered at the AP, otherwise, its value gives the relative starting time slice for the transmission of broadcast frames within the current beacon interval.
Other SIs can't be set to 0 (otherwise the SI can be omitted) and each SI corresponds to an AID whose bit is set in the Partial Virtual Bitmap. As shown in FIG. 2( a ), a destination whose AID is set to 1 in the Partial Virtual Bitmap looks to an SI in the Slicing Map having a relative position consistent with the position of the destination's AID bit in the Partial Virtual Bitmap. For a destination (AID) having a bit equaling 0 in the Partial Virtual Bitmap, there is no SI corresponding to it in the slicing map field.
For example, in FIG. 2( a ) AID 4 in the Partial Virtual Bitmap is set to 1. The destination corresponding to AID 4 looks to the fourth SI position in the slicing map field (AID 0 , AID 1 , AID 2 , AID 4 ). A further example is AID 7 which looks to the fifth SI position in the slicing map field (AID 0 , AID 1 , AID 2 , AID 4 , AID 7 ). Thus a destination determines which SI to look at by knowing it's own AID and the number of prior AIDs having bits set to one in the Partial Virtual Bitmap. The destination station then reads the number indicated by the bits in the stations respective SI.
3) Partial Virtual Bitmap Field:
In the original TIM, each bit corresponds to one client identified by an AID. With reference to FIG. 5 , the AIDs are assigned for all clients ( 32 - 1 to 32 - n ) within the BSS ( 50 ) during the association procedure, and it is used to handle the buffered unicast frames at the AP ( 31 ). In an exemplary embodiment of a TIM disclosed herein, the AIDs are still used, not only for unicasting, but also for multicasting. Each multicast group is assigned an AID during the negotiation phase when a client joins a multicast group. The details are described in the following section.
As an AP primarily deals with MAC layer information, a multicast group is differentiated using its MAC address. Therefore each multicast group is assigned a MAC address and a corresponding AID. Though the multicast IP addresses and their corresponding MAC addresses are not strictly one-to-one mapping, it is still reasonable to maintain an AID for each multicast MAC address rather than a multicast IP address at the AP, as the possibility of two multicast IP addresses mapped to one MAC address is extremely small.
Note that though the two fields, slicing control and slicing map field, are appended after the partial virtual bitmap as two components of the TIM structure in FIG. 2( a ), it is also possible that the two fields can be used as a new element in a frame.
FIG. 2( b ) is an exemplary structure of the new element containing the two fields. The new element may be inserted immediately after the TIM element to send within the beacon frames, or it may be piggybacked onto another type of frames to all mobile stations after the launching of a beacon frame.
For clarity, the following descriptions are based on FIG. 2( a ), but they can be applied to FIG. 2( b ) without modification.
Time Slicing Scheme
The time slicing scheme primarily deals with the processing of the buffered frames for the PSM mobile stations. In other cases, for example, when a client stays in active mode, all unicast frames destined for it may be handled at the AP in its normal way.
With reference to FIG. 6 , the AP 610 works as the central coordinator and scheduler during the Time Slicing procedure. All incoming frames that are buffered at the AP according to the 802.11 power saving rules are processed according to the Time Slicing procedure. For example frames may be received by the communications interface 620 from a wired or wireless network. The frames may be buffered in memory 650 .
As pointed out above, before a beacon frame is launched, the AP divides the beacon interval into a fixed number of slices of equal length. In an exemplary embodiment the processor 640 of FIG. 6 divides the beacon interval into the fixed number of slices. The number of slices usually has a form of 2 n −1, with n being the number of bits used in the slicing control field of the TIM as shown in FIG. 2( a ) or FIG. 2( b ). After the slice division, the AP 610 is responsible for assigning slices to the pending frames.
As disclosed herein, an AP 610 is assigned to each multicast MAC address as for a mobile station, and all the pending frames are grouped according to their pertaining AIDs. The AP 610 employs a scheduling algorithm to calculate the number of consecutive slices for each group and the exact position of the starting time for these slices. When the AP 610 has finished this procedure, it fills the fields in the TIM structure, particularly the slicing map field (SI) that announces the starting points of the assigned slices for each AID, and then sends the beacon out through transceiver 630 .
Each station in power saving mode maintains an AID list, containing one unicast AID that is assigned by the AP during the association phase, and several other multicast AIDs assigned by the AP when joining multicast groups. Note that AID 0 is used for broadcast and it is known by all stations, so it maybe omitted in the list held in each station. The AID list held by the station is used to check the Partial Virtual Bitmap of the TIM after a beacon frame is received. If a bit corresponding to an AID in the station's list is set in the bitmap, the station goes further towards the slicing map field and locates the SI that matches the bit. The value of SI is used to calculate the time for it to wake up to receive frames. Thereafter the station can enter into sleep state and wake up at the calculated time. If multiple bits corresponding to AIDs in the station's list are set in the bitmap, then the station has to wake up and sleep several times within a beacon interval. However, as the starting time of the beacon period of the station is a little later than that of the AP, caused by the delay of beacon frames, it is reasonable for the station to wake up earlier for some time than expected so as not to miss the transmission of pending frames by the AP. Once the transmission of pending frames for this AID concludes, the station may return to sleep state, or keep in active state, if it has to wake up in a short time later.
The AP is responsible for controlling the starting time and lasting period for the transmission of pending frames for each group. The AP gains control of the wireless medium through a Priority Inter-frame Space (PIFS) as used for beacon frames. The PIFS is shorter than Distributed Inter-Frame Space (DIFS), so the AP takes an advantage over the other stations to gain the wireless medium. Once the starting time of slices that are assigned to some AIDs comes, the AP senses the wireless medium and tries to access the medium to commence the transmission of buffered frames. It is recommended that the AP hold the control of the wireless medium by protection, until all buffered frames for this SI are delivered out, or the next SI comes.
Multicast Association Procedure
As pointed out above each multicast group is assigned an AID during the negotiation phase when a client joins a multicast group with each multicast group having an MAC address. The AP maintains a mapping table between AIDs and MAC addresses for the purpose of managing the virtual bitmap within the TIM structure. AID 0 is reserved for broadcasting, while other positive integers are used for both multicasting and unicasting. A unicast AID is assigned to a station during its (re) association procedure with the AP, and a multicast AID is assigned to a group during a multicast association procedure, as described below.
An exemplary frame format of a multicast association request, multicast association response and multicast disassociation are shown in FIG. 3 . Practical implementations are not restricted to these drawings, as there may be multiple variants to perform similar functions as described herein.
The multicast association procedure works in a similar manner to the (re)association procedure defined in the 802.11 standard. Once a station has been confirmed by the router (through IGMP messages) that it has joined a multicast group, it initiates a multicast association request to the AP, with some field of the request being the MAC address of the multicast group. For example FIG. 3 shows the Multicast Association Request with the field MA used for the MAC address which is calculated from the corresponding multicast IP address.
The AP responds to the station with a multicast association response frame filled with an AID for that MAC address. For example FIG. 3 shows the Multicast Association Response with the field AID used by the AP for including the AID assigned by the AP for the multicast MAC address.
The AP may optionally maintain a member list for a multicast AID, of which a member corresponds to a station that joined the multicast group. A member list is useful for the AP to determine whether or not an incoming multicast frame pertaining to this multicast group should be buffered. If all members in the list are in CAM, then the frame is not buffered for power saving reasons.
When a station decides to quit a multicast group, it may choose to send a multicast disassociation frame to the AP with one field to be the multicast MAC address of the group. As shown in FIG. 3 , the Multicast Disassociation frame includes the field MA which has the multicast MAC address calculated from the corresponding multicast IP address. However, the multicast disassociation procedure is not mandatory. If there is no member list maintained at the AP for a multicast AID, a station does not have to initiate a multicast disassociation procedure to quit the group.
As mentioned, the MAC address of a multicast group can be derived from its IP address. The last 23 bits (of 32) of the multicast IP address is used as the least significant 23 bits (of 48) of the MAC address, and the other 25 bits are fixed for the MAC multicast address. Though the mapping between these two addresses is not one-to-one, the possibility of two multicast addresses mapping to one MAC address can be ignored (1/2 23 ). A direct mapping technique is employed to map each group to an AID to enable the physical devices to become aware of the multicast frames buffered for the multicast group at the AP.
Service Period (SP)
The concept of service period as an embodiment of the time slicing scheme is described and exemplified in FIG. 4 . A service period (SP) consists of one or more consecutive time slices that are assigned by the AP through the slicing map field in the beacon frames. One service period (SP) may correspond to one or more AIDs, thus one or more destinations, depending on the number of identical SIs in the slicing map. Two AIDs with identical SIs share the same SP. A SP starts at the ith time slice in the current beacon interval, i being the value of SI for this SP, and ends up before the time slice identified by the next immediate SI. Therefore, the starting and lasting time are determined by the SIs in the slicing map.
FIG. 4 illustrates a simplified diagram of an exemplary relationship among AID, SP and SI. As shown in FIG. 4 the Slicing control indicates n=4; therefore, each SI includes 4 bits and the number of time slices is determined from 2 4 −1=15. AID 0 is set to 1 indicating broadcast frames are buffered. As indicated in the first SI the broadcast frames will begin at time slice 1 and will end with time slice 3 , since time slice 4 will begin the transmission of buffered frames for AID 1 . The second SP or SP 2 is assigned to AID 2 as shown in FIG. 4 and starts at the fourth slice and ends up at the sixth slice, where the SI of the AID 2 equals 4 and the next greater SI equals 7. Thus each of SP 1 and SP 2 occupy 3 consecutive slices within the given beacon interval. As seen SP 4 occupies 4 consecutive slices.
In an embodiment of the present invention the AP is responsible of administrating the time slices, including the setting of a proper number of slices within one beacon interval, the allocation of time slices to an AID and the scheduling of buffered frames for transmission. The AP also assembles the information of slice allocation and fills in the slicing map field to be sent with the beacon frames. Moreover, the AP should gain control of the wireless medium in time to ensure the progress of the time slicing.
The frame transactions within the SP are implementation dependent, for example the transactions between a AP and a station for delivering the buffered frames. A protection method through network allocation vector (NAV) channel updating to avoid contention during transmission of pending frames may be implemented, as it squeezes the total time of the scheduled frame delivery for this SP, thus conserves power for the station. In spite of the manner of pending frame transaction during the SP, other stations can access the wireless channel using the normal distributed coordinated function (DCF) rules.
It is possible that the pending frames for a destination may not be delivered out within the appointed SP. In this situation, the AP can choose to send the remaining frames at its convenience in the current beacon interval or assign new time slices for their delivery in the next beacon interval.
Power State Transition of the Stations
In an embodiment of the present invention a station in power saving mode transitions between awake and sleep states according to the following rules:
1) The station shall enter the awake state prior to each TBTT (Target Beacon Transmission Time) to receive beacon frames.
2) If the SPs that are allocated for this station or for a multicast group to which this station belongs are not immediately transmitted after the beacon, the station can enter into the sleep state and wake up prior to the next targeting SP, otherwise, the station remains awake until the current SP concludes.
3) The station can choose to sleep within the SP, once it ensures that all buffered frames for it during this SP have been delivered. However, it is required to wake up prior to the next targeting SP.
From the foregoing description, one skilled in the art can ascertain certain features and advantages gained through this methodology. For example more power conservation should be achieved than that of the original standard. A station may wake up at the expected time to receive buffered frames from the AP and return to sleep state once the transaction concludes. Thus the energy drained while in an idle state is greatly reduced. Moreover, the activities of other stations have little effect on the power performance of the current station in PSM.
In addition, the delivery of the pending frames at the AP can be scheduled in a much more flexible manner. The AP can choose time slices for the transmission of the buffered frames within a beacon interval by utilizing it's own scheduling algorithms. This solution provides a possibility for the AP to process the pending frames in an optimized fashion, complying with the requirements of the stations.
These and other features and advantages of the present invention may be readily ascertained by one of ordinary skill in the pertinent art based on the teachings herein. It is to be understood that the principles of the present invention may be implemented in various forms of hardware, software, firmware, special purpose processors, or combinations thereof.
Most preferably, the principles of the present invention are implemented as a combination of hardware and software. Moreover, the software is preferably implemented as an application program tangibly embodied on a program storage unit or computer readable medium. The application program may be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (“CPU”), a random access memory (“RAM”), and input/output (“I/O”) interfaces. The computer platform may also include an operating system and microinstruction code. The various processes and functions described herein may be either part of the microinstruction code or part of the application program, or any combination thereof, which may be executed by a CPU, whether or not such computer or processor is explicitly shown. In addition, various other peripheral units may be connected to the computer platform such as an additional data storage unit and a printing unit.
It is to be further understood that, because some of the constituent system components and methods depicted in the accompanying drawings are preferably implemented in software, the actual connections between the system components or the process function blocks may differ depending upon the manner in which the present invention is programmed. Given the teachings herein, one of ordinary skill in the pertinent art will be able to contemplate these and similar implementations or configurations of the present invention.
Although the illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as set forth in the appended claims.
All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor 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.
The functions of the various elements shown in the figures 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 figures 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 implementer 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 that 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. | A method and apparatus for improving power performance of a wireless adapter which adopts a time slicing scheme by dividing a beacon interval into multiple slices, and assigning these slices to the stations through the beacon frame. The stations wakeup at the appointed slices to receive their buffered frames from an access point, and may enter into sleep state once the transactions conclude. A further embodiment including formatting data into a control frame for use in a wireless local area network, the frame including an indication, for each station associated with the wireless local area network, whether frames are buffered awaiting transmission to each respective station, a number of time intervals between control frames, and at which time interval the transmission of the buffered frames will begin for each station having buffered frames awaiting transmission. |
FIELD OF THE INVENTION
This invention relates to a drain valve and more particularly to an automatic pneumatically operated drain valve device for removing collected moisture and/or contaminants from an air dryer of a compressed air system.
BACKGROUND OF THE INVENTION
It is common practice in compressed air systems to pass the pressurized air through an air dryer prior to being delivered to a storage reservoir or the like. The air dryer, such as, a C-1 air dryer, manufactured and sold by the Westinghouse Air Brake Company of Spartanburg, S.C., not only extracts water vapor, but also removes other contaminants entrained in the compressed air. The collected contaminants must be periodically drained from the C-1 type of air dryer. In order to remove the condensates, the air dryers are frequently provided with a normally closed pneumatically operated drain valve. In practice, the drain valve is opened during the compressor "OFF" cycle to permit the flow of purge air to atmosphere, and exhausts the discharge system of the air compressor unit. Presently, a D-4 type of pneumatic activated drain valve is used in combination with the C-1 air dryer. The existing drain valve employs a piston-stem assembly in which a brass piston is attached to a stainless steel stem. The piston includes a pair of annular grooves for receiving rubber O-rings which slide within a stainless steel bushing which is press-fitted within the housing or casing of the drain valve. The remote end of the stem carries a valve seal which is cooperatively associated with a valve seat located within the housing. A compression biasing spring engages the piston member and normally urges the valve seal toward the valve seat to a closed position when the compressor is turned ON. When the compressor is turned OFF, a pressure chamber is pressurized to cause the linear movement of the piston stem assembly to open the valve seat and to purge the moisture vapor from the air dryer. It has been found that there is a leakage and seizure problem with these previous drain valves. The lack of lubrication causes wear on the rubber O-rings which results in leakage. In addition, the absence of lubricity results in high static and dynamic frictional forces which act against the spring loading and therefore the valve seal does not completely and tightly seal against the valve seat so that there is a constant air seepage which can result in the continuous operation of the air compressor.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide a new and improved drain valve for removing collected moisture from a compressed air system.
Another object of this invention is to provide a unique automatic pneumatically operated drain valve for extracting the condensate from an air dryer of a compressed air system.
A further object of this invention is to provide an automatic drain valve device employing a rolling diaphragm for actuating an integral piston stem assembly which opens a ball valve for expelling moisture collected in an accumulating chamber to atmosphere.
Still another object of this invention is to provide an improved pneumatically actuated drain valve having a normally seated ball valve which is closed by the force of a compression spring and is assisted by the air pressure in the cavity of an air dryer of a compressed air system.
Still a further object of this invention is to provide novel drain valve device which vents accumulated moisture from an air dryer through a pneumatically operated ball valve and through a sintered exhaust muffler to atmosphere.
Yet another object of this invention is to provide an automatic pneumatically operated drain valve device for periodically removing moisture and contaminants from a compressed air system, said drain valve device comprising, a drain valve body and a cover member, a rolling diaphragm clamped at its outer periphery between the drain valve body and the cover member, a pressure chamber located on one side of the rolling diaphragm adjacent the cover member, a piston and stem located on the other side of the rolling diaphragm, a ball valve disposed in the drain valve body, a biasing spring normally urging the ball valve to a closed position, a moisture accumulation chamber located in the drain valve body, the piston and stem moving the ball valve to an open position to remove the moisture and contaminants from the moisture accumulation chamber when the pressure chamber is pressurized.
Yet a further object of this invention is to provide a unique drain valve device which is economical in cost, simple in design, reliable in service, durable in use and efficient in operation.
DESCRIPTION OF THE DRAWINGS
The above objects and other attendant features and advantages will be more readily appreciated as the present invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:
FIG. 1 is a top sectional view of an automatic pneumatically operated drain valve device which is mounted to the body of an air dryer of a compressed air system;
FIG. 2 is a front elevational view of the valve of FIG. 1;
FIG. 3 is a side elevational view of the drain valve device of FIG. 1 which is devoid of the air dryer.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, and in particular to FIGS. 1 and 2, there is shown the automatic pneumatically actuated drain valve device generally characterized by numeral 1 which is mounted to an air dryer 2 of a compressed air system. As shown in FIGS. 1, 2, and 3, the drain valve device 1 embodying the invention includes a casing or housing 10 that has integrally formed therewith a mounting flange 11. The flange member 11 has a pair of spaced apart through bore holes 12 and 13 through each of which extends a pair of threaded studs 14 and 15, respectively. In practice, the body of the air dryer is designed with a flange face 16 on which the drain valve 1 is mounted by the threaded studs 14 and 15 which are screwed into a pair of threaded holes which are in alignment with bore holes 12 and 13. The drain valve 1 is securely fastened to the threaded free ends of the studs 14 and 15 by nuts 17 and 18 and lock washers 19 and 20, respectively. It will be seen that the air dryer 2 is provided with an opening 21 which opens directly into one end of a collection or accumulation chamber 22 in the drain valve device 1 in the area of the flange 11. Thus, the moisture or water condensation in the air dryer may be accumulated in chamber 22 to be expelled to atmosphere as will be described in greater detail hereinafter. The other end of the collection chamber 22 is provided with a cylindrical type of valve seat member 23 which is sealed by packing material or rubber O-ring 24. It will be seen that the cylindrical member 23 includes a conical valve seat surface 25 on which a stainless steel ball valve 26 is normally seated by the force of a compression biasing spring 27 and the compressed air pressure present in the accumulation chamber 22. A cage member 28 includes an internal spring seat 29 which engages one end of the biasing spring 27 while the other end of the biasing spring 27 engages the peripheral surface of the ball valve 26. A sealing ring 30 is disposed between the cylindrical member 23 and the cage member 28, while a sealing ring 49 is disposed between cylindrical member 23 and the internal wall of the housing 10. A retaining spring 31 urges the cage member 28 to the position shown in FIG. 1, and an internal retaining ring 32 holds the spring 31 in place. An annular sealing ring or gasket seal 33 is disposed between the flange 11 and the face 16 of the air dryer 2.
As shown in FIG. 1, an operating stem or push rod 34 is slidably disposed within an internal bore 35 found in the casing 10. The one or free end of the operating stem 34 is adapted to engage the periphery of the ball valve 26 while the other end is integral with a follower member or piston 36 which is carried by a rubber rolling diaphragm 37. The diaphragm 37 includes an annular bead 38 formed on the outer peripheral edge. The annular bead 38 is clamped to the casing 10 and a cap member 39 by a plurality of bolts 40 and lock washers 41. A relief port 50 is formed in the body of housing 10 to eliminate strain and deformation on the underside of the diaphragm 37 by being vented to atmosphere. A pressure chamber 42 is formed between the inner surface of the cap member 39 and the outer surface of the rolling diaphragm 37. An elbow fitting 43 is threadedly screwed into an inlet port 45 which is in constant communication with the delivery side of a compressor governor or control unit solenoid (not shown) via conduit or pipe 44.
Referring now to FIGS. 2 and 3, it will be appreciated that the accumulated moisture is discharged to atmosphere through a sintered exhaust muffler member 46 which is threadedly screwed into the underside of the casing 10. Further, it will be seen that an electrical heater element 47 is located at the upper side portion of flange member 11. The heat element is energized via cable 48 during cold and/or freezing weather in order to prevent the collected moisture from freezing so that the purging action will operate satisfactorily even during the wintertime.
In describing the operation, let us initially assume that the compressor is running or turned on, the governor valve device or alternatively, the control unit solenoid device, ensures that the conduit 44 and, in turn, the pressure chamber 36 are not pressurized so that the ball valve is closed by the compressive force of return spring 27 and the pressure force in chamber 22. With the ball valve 23,26 seated, the moisture or water droplets formed in the air dryer cavity is collected in the accumulation chamber 22. Now when the compressor is unloaded or turned off, the governor valve device or the control unit solenoid device causes the pressurization of the pressure chamber 22 via conduit or pipe 44. The build-up of air pressure in chamber 22 causes movement of the rolling diaphragm 37 and results in linear shift of the follow member 36 and the operating stem to the left as viewed in FIG. 1. Accordingly, the stem 34 unseats the stainless steel ball 26 from the valve seat 25 so that accumulation chamber 22 is vented to atmosphere via the exhaust muffler 46. Thus, the air dryer 2 is purged and is ready for the next running cycle of the air compressor at which time the chamber 22 and pipe 44 are depressurized so that the returned spring and air pressure in the cavity of the air dryer 2 and chamber 22 close and positively seal the ball valve 23,26 and shift the stem 34, the follower 36 and the diaphragm 37 to the right as viewed in FIG. 1 so that the automatic drain valve device is ready for the next purging cycle.
It will be appreciated that the use of a rolling diaphragm improves the overall efficiency of operation since there is little, if any, frictional losses in moving the piston stem assembly which effectively opens and closes the ball valve. In addition, the rolling diaphragm provides a positive seal between the pressure chamber and the exhaust muffler which is open to atmosphere. Further, the use of a conically shaped valve seat and a stainless steel ball which is closed by a compression spring and is supplemented by the fluid pressure in the cavity of the air dryer eliminates permanent setting problems common in rubber type of valves. The use of an integral piston stem assembly eliminates the need of special fasteners and minimizes the machining requirements.
Thus, the present invention has been described in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same and having set forth the best mode contemplated of carrying out this invention. It will be seen that the subject matter, which I regard as being my invention, is particularly pointed out and distinctly set forth in what is claimed. It will be understood that variations, modifications, equivalents and substitutions for components of the above specifically-described embodiment of the invention may be made by those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims. | A pneumatically actuated drain valve device for venting the moisture in an air dryer to atompshere including a rolling diaphragm for linearly moving a piston stem assembly to unseat a spring and pressure biased stainless steel ball valve from its conically shaped valve seat to permit the collected moisture in an accumulation chamber to pass through a sintered exhaust muffler to the atmosphere. |
TECHNICAL FIELD
[0001] The field of this invention relates separators in a closed crankcase ventilation system.
BACKGROUND OF THE DISCLOSURE
[0002] Government regulations relating to environmental concerns have mandated that many engines have a closed crankcase ventilation system. Commonly, these closed systems re-circulate any blow-by gases escaping from the combustion chambers and passing into the crankcase back into the air intake system. These blow-by gases, which are loaded with unburned gaseous hydrocarbons, are then re-circulated back to the intake manifold to be burned upon the next pass into the engine.
[0003] However, the crankcase gases are also usually loaded with oil particulates. Under extreme conditions, excess oil passing through the intake system may cause harm to the engine and cause more pollutants than what was being eliminated by the re-circulation of the blow-by gases. Thus, oil needs to be separated out before the gases are reintroduced into the air intake system of the engine and re-burned.
[0004] One present in-line closed re-circulation system is disclosed in U.S. Pat. No. 4,724,807 which has an in-line separator made with conduits with arcuate channel walls forming a convoluted arcuate pathway for the exhaust gas/oil mixture. The separator is interposed between the clean air intake filter and the turbo-compressor air inlet system. The position of this separator requires that the separator have a moderately small size to fit between the air filter and turbo intake and requires that it be downstream from the crankcase depression regulator. These factors limit the capacity and effectiveness of the separator returning oil against a substantial differential pressure to the positively pressured crankcase.
[0005] What is needed is an expeditiously constructed separator system that has enough capacity to prevent oil from entering the air intake in a cylinder kit failure situation and eliminates the resistance of draining oil back into a positively pressurized crankcase.
[0006] In addition, there is a need for a separator system that protects the engine against a sudden increase in oil discharge due to operating conditions, including extreme tilt of the engine during operation.
SUMMARY OF THE DISCLOSURE
[0007] In accordance with one aspect of the invention, a closed crankcase re-circulation system for an internal combustion engine includes an exhaust gas-oil separator operably interposed between an engine breather and a crankcase depression regulator. The exhaust gas-oil separator has an inlet in communication with an outlet of an engine breather for communication with the internal space of the crankcase. Commonly, the engine breather may be mounted in the rocker arm cover with the engine block and cylinder heads having passages to the crankcase.
[0008] A gas outlet is in communication with a line leading to an air intake system of the engine. The gas outlet is positioned at a high portion of the separator. The line has a crankcase depression regulator mounted downstream from the separator. An oil drain outlet is in communication with the crankcase for draining oil back thereto.
[0009] Preferably the separator is longitudinally extending from the inlet to the outlet and drain. The oil drain outlet is at a lower portion of the separator. Baffles are interposed between the inlet and the gas and oil drain outlets. Preferably the baffles transversely and alternately extend from opposite sides of the separator to form a convoluted passage for the blow by gasses as they pass from the inlet to the gas outlet.
[0010] The separator desirably has a floor surface canted downwardly from the inlet to the oil drain outlet with the oil drain outlet located at a low portion of the canted floor surface to provide for flow of the separated oil to the oil drain outlet.
[0011] In one embodiment the separator has a generally frusto-conical shape extending from the inlet to the gas outlet and oil drain outlet. In this embodiment, it is preferable that each baffle has an oil drain passage located at a low lateral point at the floor surface to provide for downward flow of the oil through the baffle and toward the drain. It is also preferable that a filter media is interposed between an end wall in proximity to the gas outlet and a last downstream baffle. The filter media is operable interposed between the gas outlet and the oil drain outlet.
[0012] In another embodiment, the separator has a generally rectangular shape in plan view with vertical sidewalls and vertical end walls. The floor surface is generally flat in the lateral direction. The baffles alternately extend from the vertical sidewalls. It is desirable in this embodiment that the inlet is positioned at an upper section of one end wall adjacent a higher end of the floor surface. The gas outlet is positioned at an upper section of an opposite end wall adjacent to the lower end of the floor surface. The oil drain outlet is positioned at a lower section of the opposite end wall.
[0013] In accordance with another aspect of the invention, a separator for a closed crankcase ventilating system includes a generally longitudinally and horizontally extending body with an inlet at an upstream end and a gas outlet and oil drain outlet at a downstream end. The separator has a floor surface canted downwardly from the upstream end to the downstream end. The oil drain outlet is located at a low portion of the canted floor surface. A plurality of baffles transversely extend laterally within the body and are alternately to opposite sides of the body.
[0014] Preferably, the separator body has a generally frusto-conical shape extending from the inlet to the gas outlet and oil drain outlet. Preferably, each baffle has an oil passage located at a low lateral point at the floor surface to provide for downward flow of the oil through the baffle and toward the oil drain outlet.
[0015] In this fashion, a separator has the efficiency and capacity to adequately separate sufficient oil form the crankcase gases in a situation where a cylinder kit fails which significant blow by of oil and blow by gasses pass into the crankcase. In this way, the air intake system and turbo charge system are more adequately protected when a cylinder kit failure occurs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Reference now is made to the accompanying drawings in which:
[0017] [0017]FIG. 1 is a side elevational view of an engine incorporating a separator in accordance with one embodiment of the invention;
[0018] [0018]FIG. 2 is an enlarged side elevational view of the separator shown in FIG. 1;
[0019] [0019]FIG. 3 is a plan view of the separator with the top removed for viewing the baffles therein;
[0020] [0020]FIG. 4 is an end view of the downstream end of the separator;
[0021] [0021]FIG. 5 is a view similar to FIG. 1 illustrating a second embodiment of the invention;
[0022] [0022]FIG. 6 is an enlarged side elevational and partially segmented view of the separator shown in FIG. 5;
[0023] [0023]FIG. 7 is an end view from the downstream end of the separator shown in FIG. 6; and
[0024] [0024]FIG. 8 is a top plan view showing the alternating baffles within the separator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] Referring now to FIG. 1, an engine 10 has an oil breather 12 connected to the rocker arm cover 13 . The breather 12 is connected to a line 16 that is connected to an inlet 18 of a separator 20 often referred to as an air-oil separator. The separator 20 has a drain outlet 22 connected to a line 24 , preferably with a one way check valve 26 therein that leads back to the crankcase 28 in engine 10 . The oil breather 12 is conventionally in communication with the crankcase 28 via passages through the engine block and cylinder head that are not shown for simplicity of the drawing.
[0026] The separator 20 also has an outlet 30 that is connected to a line 32 that has a crankcase depression regulator 34 . The line 32 extends beyond the crankcase depression regulator 34 and is connected to the air intake system generally indicated at 35 . The air intake system 35 has an air intake 36 and turbocharger 38 which has a line 40 leading back into the intake manifold 42 . The turbocharger 38 is driven by exhaust gases passing from exhaust manifold 39 to exhaust line 41 .
[0027] The separator 20 can be described in more detail with reference to FIGS. 2 - 4 . As shown in these figures, the general shape of the separator 20 is rectangular in the plan view as shown in FIG. 3. The separator has a flat top 42 with vertical opposing side walls 44 , vertical opposing inlet end wall 46 and downstream end wall 48 and a sloping or canting floor surface 50 as shown in FIG. 2. This shape is more conducive to packaging or placing the air oil separator 20 above the engine where a wide flat shape is desirable for packaging purposes.
[0028] The floor surface 50 slopes downwardly from the inlet end wall 46 to the outlet end wall 48 . The inlet 18 intrudes at an upper section of the inlet end wall 48 . The inlet 18 may be an extending inlet pipe 52 for allowing a line to be easily coupled thereto. The downstream end wall has an oil drain outlet 22 at a lower section at the floor surface and a gas outlet 30 at an upper end of the end wall 48 . As shown in FIG. 4, the two outlets 30 and 22 are placed at opposing corners of the downstream end walls and may be similarly constructed to inlet 18 with an extending pipe 52 .
[0029] As shown in FIG. 3, a plurality of flat plate baffles 58 extend from the two side walls 44 in alternating fashion to provide a zig-zag convoluted path for the gas and oil flow within the separator to provide sufficient length and turbulence to drop the oil particulates from the blow-by gasses during the gasses tortuous path through the oil gas separator. The dropped oil flows on the floor surface 50 following the convoluted path along the downward slope to the drain outlet 22 . The oil then passes through the connected line 24 and through the one way check valve 26 and back to the crankcase 28 . The pressure differential between the separator and the crankcase is insignificant because crankcase depression regulator 80 is downstream from the separator. Thus, the mere weight of the oil is sufficient to open the check valve 26 and allow the oil to reenter the crankcase. The gases also continue along the tortuous path provided by the baffles to the upper gas outlet 30 . The gasses pass the crankcase depression regulator 80 and back into the air intake system.
[0030] The separator 20 is sized sufficiently to provide for substantial separation of oil from blow by gasses in the event that a cylinder kit completely fails. While this size varies with relation to the size of the engine and size of the cylinders, an air oil separator having the interior dimensions of 12 inches in length, 8 inches in width and 6 to 8 inches in depth is sufficient size for an engine such as a commercially available Detroit Diesel Series 2000® marine pleasure craft engine. The baffles will cause an average minimum path length of approximately 24 inches for this dimensioned separator between the inlet and gas outlet. Additional plate baffles will increase the path length from this disclosed preferred embodiment.
[0031] A second embodiment is disclosed in FIGS. 5 - 8 . In this embodiment the separator 120 is placed along the side of the engine 10 . The outer shape of the separator 120 has a substantially frusto-conical tubular wall 154 with a longitudinal axis. The tubular wall 154 is capped at each end with vertical upstream end wall 146 and downstream end wall 148 . The longitudinal axis of the separator 120 is generally horizontal such that it has a downwardly sloping or canting floor surface 150 as shown in FIG. 2. This shape is a more conducive package when the separator 120 is positioned at a side of the engine 10 . Usually a relatively narrow and longer shape is desirable for packaging purposes at a side of an engine.
[0032] The floor surface 150 , which is merely a lower section of the frusto conical body wall 154 , slopes downwardly from the inlet end wall 46 to the outlet end wall 48 . An inlet 118 intrudes at an upper section of the inlet end wall 148 . The downstream end wall 148 has a gas outlet 130 at an upper end of the end wall 148 . An oil drain outlet 122 extends from the lower end of the floor surface 150 adjacent the end wall 148 . As shown in FIG. 7, the two outlets 130 and 122 are both near the center vertical longitudinal plane of the air oil separator.
[0033] As shown in FIG. 8, a plurality of straight plate baffles 158 extend from the opposing side sections 144 of the frusto conical body wall in alternating fashion to provide a zig-zag convoluted path for the gas flow within the separator to provide sufficient length and turbulence to drop the oil particulates from the entering crankcase blow-by gasses during its tortuous path through the oil gas separator. This dropped oil then flows from the point that it drops onto the floor surface 150 to a lower midpoint in proximity to the vertical center plane. Each baffle 158 has a flow through passage 160 along the vertical midplane to allow the oil to flow down the floor surface 150 to the oil drain outlet 154 . The oil then passes through the connected line 24 and through the one way check valve 26 and back to the crankcase oil supply in the same fashion as with the first previously described embodiment.
[0034] As shown in FIG. 7, an optional filter 162 may be interposed between the last downstream baffle 158 and the downstream end wall 148 such that all blow by gasses must pass up through the filter 162 to reach the outlet 152 . The filter provides further chances for remaining oil particles to condense or hit the filter and drop back onto the floor surface 150 and pass to the oil drain outlet 154 .
[0035] The length and inner upstream and downstream diameters for the frusto conical body again can vary with the particular application. It is foreseen that for the above mention commercially available engine, a length of 12 inches and upstream and downstream inside diameters of 6 and 8 inches, respectively is suitable dimensions for a Detroit Diesel 2000 marine pleasure craft engine.
[0036] In this fashion, substantially all significant amounts of oil are separated from the blow by gasses that enter the separator before the blow by gasses are returned to the intake manifold. The oil is easily returned to the crankcase thereby preventing any back up of blocked conditions. Furthermore, the separator is easily constructed with flat plate baffles housed in an easily constructed housing.
[0037] Variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims or plan.
[0038] The embodiments in which an exclusive property or privilege is claimed are defined as follows: | A separator for a closed crank case ventilation system has an upstream located inlet and downstream gas and oil outlets. A plurality of flat plate baffles alternately extend from opposing side walls to form a tortuous path for blow by gasses to separate the oil from the gasses. The separator is located upstream from the crankcase depression regulator such that the pressure differential between the separator and the crankcase is minimal to allow the oil to easily open the check valve and return to the crankcase. |
BACKGROUND OF THE INVENTION
1) Field of the Invention
The field of this invention relates to toasters and more particularly to a toaster that includes a food cutting holder that is designed to be used by a human user to facilitate sectioning of a food item, such as a bagel, in order to facilitate toasting of the item within the toaster.
2) Description of the Prior Art
In the past, there have been numerous designs for toasters, the most common form of toaster being for slices of bread. Such toasters can also be used to toast bagels and muffins. It is generally necessary for the user to slice the bagels and muffins into two or three pieces prior to being toasted since such are too wide for the opening in the top of the toaster. The resulting pieces are to have a width which will be less than the opening that is provided within the toaster. The conventional slicing procedure for a bagel requires the user to place the bagel on its circumferential edge in an upright manner and be held by the hand of the user. The user then directs a knife blade longitudinally through the bagel attempting to divide the bagel into two relatively equal halves. This type of cutting procedure is difficult for many people and has resulted in a large number of hand cuts. Additionally, some people prefer to cut the bagel into three pieces as opposed to two which produces narrower separate pieces which not only facilitate the toasting procedure but also produces a more toasted end food product. The dividing of a bagel into thirds by this hand technique causes the user to be even more prone to injury. There is a need to incorporate a simplified and safe form of holder device in conjunction with a conventional toaster that can be used by the user to slice a bagel or muffin into a plurality of separate pieces with the slicing procedure to be accomplished in a safe manner.
The present inventor has been assigned U.S. Pat. No. 5,522,306, issued Jun. 4, 1996, entitled TOASTER AND CUTTER. The subject matter of this patent describes a cutter mechanism mounted externally in conjunction with a toaster. The subject matter of the present invention does not include the use of a cutter mechanism but only includes the use of a holder with the cutting being provided separately.
SUMMARY OF THE INVENTION
In a toaster which has a toaster housing, there is formed a small compartment. Within that small compartment there is to be storable a food cutting holder. The food cutting holder is to be manually extractable from the compartment and locatable on a supporting surface. A food item, such as a bagel, is to be mounted on edge in conjunction with the food cutting holder. One embodiment of the food cutting holder is to include at least one front set of aligned slots which are to function as a guide for a knife blade. Moving of the knife blade through the food item and within the aligned slots results in division of the food item into two equally sized pieces. Another embodiment of the food cutting holder utilizes a platform which has an inner edge pivotly attached to the toaster housing. The inner edge of the platform has mounted thereto a back wall which is mounted substantially at a right angle relative to the platform. Located directly adjacent the outer edge of the platform is a front wall with this front wall being pivotly attached to the platform. This front wall is biased by a spring in a direction toward the back wall. Between the back wall and the front wall is located a confining space. The food item is to be located within the confining space and be clampingly held between the front wall and the back wall. Surfaces of both the front wall and the back wall which are to contact the food item include a holding means in the form of a series of short spikes. When the food cutting holder is in its extended position and a food item is mounted within the confining space, a knife blade can be easily manually moved through the food item without concern for the food item becoming accidently dislodged from the food cutting holder or the user cutting one self. The food cutting holder is to be pivotable into the compartment when it is desired to store the food holder when not in use.
The primary objective of the present invention is to construct a holder for a food item in conjunction with a toaster where the holder will facilitate the cutting of the food item into a plurality of separate pieces.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a toaster which is constructed to include a first embodiment of food cutting holder of this invention showing the food cutting holder in its storage position;
FIG. 2 is an isometric view showing the food cutting holder in its extended position available for usage;
FIG. 3 is a cross-sectional view through the first embodiment of the food cutting holder of this invention taken along line 3--3 of FIG. 2;
FIG. 4 is a cross-sectional view through a portion of the first embodiment of the food cutting holder of this invention taken along line 4--4 of FIG. 3;
FIG. 5 is a cross-sectional view through a portion of the food cutting holder of the present invention taken along line 5--5 of FIG. 3;
FIG. 6 is an isometric view of the food cutting holder of the present invention showing the food cutting holder in an extended position and being used to divide a food item, such as a bagel, into two separate pieces;
FIG. 7 is an isometric view of the second embodiment of food cutting holder of this invention showing the food cutting holder in its storage position;
FIG. 8 is an isometric view of the second embodiment of food cutting holder of this invention showing the food cutting holder in its extended position available for usage; and
FIG. 9 is an isometric view of a modified form of the second embodiment of food cutting holder of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring particularly to the drawings, there is shown in FIG. 1 a toaster 10 which has a toaster housing 12. The toaster housing 12 is basically constructed of sheet material with generally a metal or plastic being preferred. Included within the toaster housing 12 is a control section 14 from which extends a control knob 16. Adjusting of the control knob 16 will vary the length of time of the toasting procedure on the item of food which is deposited within the opening 18 of the toaster 10. The toaster housing 12 also includes a cutting board 11 which is movable from a storage position against the toaster housing 12 to an extended position shown in FIG. 1. When in the extended position, the toasted product from the toaster 10 is ejected from dispensing opening 13 onto cutting board 11.
Formed within the toaster housing 12 is a compartment 20. Integrally formed with the toaster housing 12 and connecting with the compartment 20 is a pair of pins 22 and 24. The pins 22 and 24 are located in a facing aligned relationship. Pin 22 is to be mounted within a hole 26 formed within a side rail 27 of the platform 28. Pin 24 is mounted within a hole 30 formed within an opposite side rail 29 of the platform 28. The platform 28 is pivotable on the pins 22 and 24. Also, the platform 28 is to be easily disengagable from pins 22 and 24 so the platform 28 can be cleaned. Platform 28 is to be quickly reengagable with pins 22 and 24. The platform 28 is movable from the extended position shown in FIGS. 2, 3 and 6 to the storage position shown in FIG. 1. In the storage position shown in FIG. 1, the bottom surface 32 of the platform 28 is located flush with the toaster housing 12. The platform 28 includes a finger access recess 34 which facilitates entry of a finger of a human to then cause pivoting of the platform 28 on the pivot pins 22 and 24. The platform 28 can be pivoted to the extended position which positions the platform 28 at approximately ninety degrees displaced from the position of the platform 28 when in the storage position.
Integrally connected to the inner edge of the platform 28 is a back wall 36. The size of the back wall 36 is to substantially cover the compartment 20 when the platform 28 is in the extended position. The platform 28 includes a mass of short in length spikes 38. The purpose of the spikes 38 will be explained further on in the Specification.
Platform 28 defines an upper recessed surface which in essence forms a chamber 40. Located within the chamber 40 is a tray 42. The tray 42 is deemed to be removable from the chamber 40. The tray 42 covers about three-fourths in size of the chamber 40. The tray 42 includes a mass of holes 44. It is the function of the tray 42 to form a resting surface for the edge of the food item 46 which is shown in FIG. 6 of the drawings to comprise a bagel.
A front wall 48 is pivotly mounted by a rod 50 to the side rails 27 and 29 of the platform 28. In between the side rails 27 and 29 of the platform 28 there is mounted a cover 52 which covers the portion of the chamber 40 located directly adjacent the outer edge of the platform 28 defined by end wall 54. The inner edge of cover 52 includes upstanding tabs 62 and 64. The upstanding tabs 62 and 64 are to confine the crumbs from the food item 46 to the tray 42. The spring 56 defines a pair of coils 57 with these coils 57 being mounted on rod 50. The ends of rod 50 are mounted in holes 51 of blocks 53. There are two blocks 53. Blocks 53 are fixed to platform 28 and located within chamber 40 with one block 53 located directly adjacent side rail 27 and the other block 53 located directly adjacent side rail 29. A leg 58 extends from each coil 57 with there being two such legs 58. A leg 58 is located on each side of the recess 34. The legs 58 will pass through appropriate openings that are formed within the platform 28. These openings are not shown in the drawing. The center part of the spring 56 includes an enlarged loop 60 which abuts against the outside wall surface of the front wall 48. It is the function of the spring 56 to exert a continuous bias against the front wall 48 intending to locate such in a position shown in FIGS. 2 and 3 of the drawings. This bias of the front wall 48 is toward the back wall 36.
The tray 42 can merely fall free of platform 28 when platform 28 is turned upside down. The tray 42 is to be removed from the chamber 40 for the purpose of cleaning to remove food item crumbs that have passed through the holes 44 and are collected within the chamber 40.
The front wall 48 has a handle 66 at its upper edge thereof. It is the purpose of the handle 66 to facilitate moving of the front wall 48 in the direction of arrow 74 against the bias of the spring 56. The inner surface of the front wall 48 includes a mass of short in length spikes 68.
The operation of the first embodiment of food cutting holder which is shown in FIGS. 1-6 of the drawings is as follows: The user places a finger within the recess 34 and pivots the platform 28 to the extended position shown in FIG. 2. The user then places a finger on the handle 66 and pivots the front wall 48 in the direction of arrow 74 against the bias of the spring 56. This enlarges the confining space located between the front wall 48 and the back wall 36. Within this confined space there is to be located the food item 46 with the peripheral edge of the food item 46 being positioned against the tray 42. The user then releases the handle 66 which will cause the spring 56 to pivot the front wall 48 toward the food item 46. There is a small clamping force produced which will cause the spikes 68 and 38 to slightly penetrate the food item 46. These spikes 68 and 38 function as a holding means to hold in position the food item 46 within the food cutting holder of FIGS. 1-6. With the food item 46 now in the clamped position within the food cutting holder, the user can grasp the handle 70 of a knife and pass the knife blade 72 through the food item 46. When the knife blade 72 has passed entirely through the food item 46, the food item 46 will now be divided into two pieces. It is to be understood that the user may, if desired, conduct the knife blade 72 through the food item 46 in two passes to produce three relatively equal sized pieces of the food item 46.
Once the food item 46 is divided as desired and separate pieces are produced, the separate pieces of the food item 46 are to be removed from the confining space once again by placing a finger in conjunction with the handle 66 and pivot the front wall 48 in the direction of arrow 74. This will then permit the different pieces of the food item 46 to be extracted from the food cutting holder. The front wall 28 only needs to be pivoted ninety degrees until the bottom surface 32 comes flush with the toaster housing 12 and at this time the food cutting holder is again relocated in the storage position.
Referring particularly to FIGS. 7-9 of the drawings, there is again shown a toaster housing 76 which has a small internal compartment 78. Within the internal compartment 78 there is to be located a food cutting holder housing 80. The food cutting holder housing 80 is constructed basically of sheet material with generally a plastic being preferred. The back wall of the housing 80 defines an enlarged cut-out area 82 with the front wall of the housing 80 including a U-shaped cut-out area 84. The housing 80 has an enlarged internal chamber 86. Arrow 92 indicates the direction of movement of the food cutting holder housing 80 from the internal compartment 78. The purpose of the U-shaped cut-out area 84 is to facilitate manual grasping of the housing 80 to extract such from the internal compartment 78. The food item 46 is to be located within the enlarged internal chamber 86 in the same position as shown in FIG. 6 of the drawings. The one disadvantage of the food cutting holder shown in FIGS. 7-9 versus the food cutting holder shown in FIGS. 1-6 is that the food cutting holder in FIGS. 7-9 is restricted as to the size of the food item 46. The food item 46 has to be of a width no greater than the length of the internal chamber 86.
The food cutting holder shown in FIGS. 7 and 8 includes a pair of aligned slots 88 and 90 formed within respective end walls of the food cutting holder housing 80. It is the function of the aligned slots 88 and 90 to provide access for a knife blade (not shown) which is to be conducted through the food item 46 resulting in division of the food item 46 into two equal parts. After the food item 46 has been divided into two equal parts, the food cutting holder 80 is to be reinserted into the internal compartment 78 as depicted by the direction of arrow 92. Relocating of the housing 80 back into the internal compartment 78 can merely be accomplished by physically grabbing of the end walls of the housing 80 in a pincher type of action and then inserting the housing 80 into the internal compartment 78.
Referring particularly to FIG. 9 of the drawings, the end walls of the food cutting holder housing 80 defines elongated slots 94, 96, 98 and 100. The elongated slots 96 and 98 are aligned and slots 94 and 100 are aligned. The knife blade, which is again not shown, is to be conducted through the elongated slots 96 and 98 and then conducted through the elongated slots 94 and 100. The result will be the division of food item 46 into three substantially equal parts. | A food cutting holder mounted in conjunction with a toaster for toasting bagels, muffins, bread slices and other similar types of foodstuff. The food cutting holder is to be confinable within the housing of the toaster when in the storage position and removable from the housing when it is intended to be used. The food cutting holder confiningly locates the food item in a precise position facilitating division of the food item into a plurality of separate pieces. It is intended that these separate pieces are then to be toasted within the toaster. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser. No. 12/881,850, filed Sep. 14, 2010, which is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] As fossil fuels and other non-renewable energy sources become more costly to obtain, and as the environmental impact of the use of such fuels becomes fully known, there has been a resurgence in the popularity of renewable energy sources such as wind, solar, tidal, and other energy technologies. Of these, wind energy is not only the most ancient, but perhaps the most promising as well, due to its simplicity.
[0003] However, the efficiency of wind energy capture devices is still far less than complete. Indeed, a typical wind turbine has blades that capture only about three percent of the passing air. Coupled with the low efficiency in converting the rotating blade movement to electrical energy, this means that existing wind turbines must be quite large and quite numerous to supply a meaningful amount of energy.
[0004] In addition to being energetically inefficient, present day rotor designs also require expensive engineering and materials to generate and maintain. For example, a typical wind turbine rotor blade is in excess of 40 meters long. Such rotor blades experience significant additional structural loading in operation due to the magnitude and weight of the structure itself. Furthermore, traditional large rotor blades rotate through a very large vertical plane, leading to significant cyclic loading. This speeds the deterioration of the structure and the need for costly maintenance or replacement.
[0005] Thus, the inventor desires to improve the structural and energetic efficiency of wind energy capture devices as described hereinafter. rotor cone being rotatable about its central axis and having a plurality of veins affixed upon the outer surface of the rotor cone, for receiving a force from the moving air in order to rotate the rotor cone. A shroud surrounds the rotor cone and extends past the narrow end of the cone, opening to an open end having a diameter substantially equal to that of the cone. When moving air enters the shroud at the open end, the moving air compresses within the shroud until it reaches the cone, passes between the cone and the shroud, and impacts the plurality of veins, rotating the cone. A generator within the cone generates electrical energy. In an embodiment, a system is provided for opening the gap between the cone and the shroud under heavy wind to bypass a portion of the moving air. In a further embodiment, a weight redistribution system is provided to increase the rotational inertia of the cone as a function of the rotational speed of the cone.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0006] FIG. 1 is a simplified cross-sectional side view of a rotor cone and shroud in accordance with an embodiment of the invention;
[0007] FIG. 2 is a perspective side view of a wind turbine system cone in accordance with an embodiment of the invention;
[0008] FIG. 3 is a perspective top view of a wind turbine system cone in accordance with an embodiment of the invention;
[0009] FIG. 4 is a cross-sectional view of a rotor cone in accordance with an embodiment of the invention; and
[0010] FIG. 5 is a simplified schematic side view of the wind turbine system according to an embodiment of the invention including a weight redistribution system for automatically increasing the rotational moment of the wind turbine cone to increase the rotational energy of the system.
DETAILED DESCRIPTION OF THE INVENTION
[0011] Prior to discussing the minute details of the invention, a brief overview will be given to orient the reader. As noted above, traditional wind turbine rotor blades are energetically inefficient for at least the reason that they capture a very small fraction of the air traversing the rotor disc. Despite this small coverage, such blades are extremely long, with the end result that such turbines are not only inefficient but also structurally compromised.
[0012] The present invention eliminates both sources of loss and expense by providing a rotor disc having 360 degrees of coverage in the disc plane, and having a low rotor disc radius compared to traditional rotors. The end result is a higher capture and conversion efficiency in a structure that is mechanically far stronger than existing turbine structures. Moreover, the device described herein requires less airspace to operate, vertically and laterally, and hence allows for more efficient land usage.
[0013] Turning to the figures, FIG. 1 is a simplified cross-sectional side view of a rotor cone and shroud in accordance with an embodiment of the invention. The rotor blades have been omitted for clarity, but will be discussed in greater detail later with respect to FIG. 2 . At any rate, referring to FIG. 1 , the turbine system 100 includes an inner cone 101 and an outer shroud 103 . It will be appreciated that the figure is simplified and that numerous components and structures are omitted for clarity. The shroud 103 may be a multi-layer insulated structure so as to prevent ambient solar heat from affecting the turbine.
[0014] The inner cone 101 rotates about its central axis A, in a direction dependent upon its blade structure (not shown here). The outer shroud 103 collects incoming air at circular opening 105 and directs the collected air, under force of its inertia as well as subsequent incoming air, into a lower volume higher pressure area 107 . After passing through the lower volume higher pressure area 107 , the kinetic energy of the entrained air is extracted via spinning of the cone 101 as the air passes between the shroud 103 and the cone 101 and impacts the blades of the cone.
[0015] It will be appreciated from the figure that although the distance between the shroud 103 and the cone 101 changes little, the three-dimensional volume of the entrained air increase as the air progresses along the cone due to the increased circumference and hence increased unit volume. Moreover, it will be appreciated that although the air flow is shown as lying continuously in a single axial plane, the actual airflow will rotate as it interacts with the cone 101 . In this way, the entrained air will be subject to a centripetal force that further influences it to continue along the cone as further energy is extracted, resulting in a very efficiency of energy extraction.
[0016] Moreover, it can be appreciated from the figure that the surface of incoming air is entirely captured. This is in contrast to a traditional bladed system wherein the capture efficiency is limited by the fact the blade areas, taken together, still only account for a small percentage of the total rotor disc area.
[0017] Once the entrained air has passed the extent of the cone 101 it may flow in a laminar manner against an exit cone 109 . This prevents or minimizes turbulent flow at the exit of the shroud, thus improving efficiency.
[0018] Before discussing the manner in which the rotational energy of the cone 101 is converted to electrical energy, the details of the cone 101 will addressed in somewhat greater detail in accordance with an embodiment of the invention by way of FIG. 2 . Referring now to FIG. 2 , a perspective side view of a wind turbine system cone in accordance with an embodiment of the invention is shown. As can be seen in the perspective side view of the rotor cone 201 in accordance with an embodiment of the invention, the rotor cone 201 includes a plurality of generally axially extending and circumferentially wrapping veins or blades 203 . The blades 203 also extend in the radial dimension from the surface of the cone 201 . While the radial extent of the blades 203 is not critical, the extent should be such that the blades extend almost to the shroud (not shown) without coming into contact with the shroud. Thus, in an embodiment of the invention, the radial extent of the blades 203 is 8 inches, leaving a gap of approximately one eighth of the entire tunnel's size.
[0019] As noted above, the surface speed of the cone increases as the circumference of the cone increases. Thus, in order to minimize the spin imparted to the air stream, the blades are shaped in accordance with the changing circumference and surface speed of the spinning cone 201 , and are thus increasingly inclined in proportion to the increasing circumference. In an exit region 205 , the blade shape momentarily reverts to a less inclined configuration before terminating. This is done so that any rotational effect of the device on the air mass may be eliminated or at least partially mitigated as the air exits the device.
[0020] For ease of understanding the cone 101 / 201 is shown in front view in FIG. 3 . As can be seen, the cone 301 includes blades 303 attached to the surface of the cone 301 and extending slightly from the cone 301 . The blades are in affixed position and curved in a manner to maximize the receipt of air flow pressure for transmission into rotational energy (not shown in FIG. 3 ).
[0021] The above discussion clarifies the manner in which wind energy is efficiently converted to mechanical energy in embodiments of the invention. While mechanical energy may be directly used, it is more desirable in an embodiment of the invention to convert the extracted energy to a form that may be easily transported, stored, and used, i.e., electrical energy. To this end, FIG. 4 is a cross-sectional view of a rotor cone 401 in accordance with an embodiment of the invention, showing an electrical energy generation mechanism within the cone 401 . The figure also discloses a wind compensation mechanism that will be discussed at a later point.
[0022] The electrical energy generation mechanism in the illustrated example includes a generator 403 that is powered by the rotation of the cone 401 under the influence of the blades (not shown in this figure). The generator may operate as an AC or DC generator depending upon builder preference. The generator 403 comprises and outer portion 405 and an inner portion 407 . It is the relative movement of the inner and outer portions 405 , 407 that is used to generate electrical energy. To this end, one portion, in this case the outer portion 407 , includes a plurality of magnets, while the other portion in this case the inner portion 405 , includes a plurality of electrical conductor coils about cores, as will be appreciated by those of skill in the art.
[0023] Because it is the relative motions of the portions that creates electrical energy, in an embodiment of the invention, the outer portion 407 moves with the cone 401 , while the inner portion is geared to the outer portion 407 as to rotate in an opposite direction, thus increasing the relative speed of passage. The mechanism for this gearing is not critical, however, in an embodiment of the invention, a planetary arrangement is used. Those of skill in the art will appreciate that numerous other arrangements may be used instead without departing from the scope of the invention.
[0024] A brushed system may be used to convey the electrical energy generated in this manner to a stationary, i.e., nonrotating point, such as the frame of the system. Depending upon power requirements and capabilities, two or four brushes, or some other number, may be used. In an embodiment, magnets may be placed on the cone for additional electrical power generation, and an additional set of brushes used to convey the generated power from the rotating cone to a stationary conduit.
[0025] In an embodiment of the invention, the number of brushes engaged is variable, to accommodate changing wind conditions. In particular, in the illustrated system, the cone 401 is configured to be pushed back against spring 409 in the presence of strong winds, in order to preserve the structure. As the cone 401 is pushed rearward under heavy wind, the distance between the cone 401 and the shroud (not shown) increases, allowing a greater volume of air to bypass the cone 401 and associated blades. Thus, the system is self-correcting to avoid excess strain.
[0026] Further, as the cone 401 moves rearward, sliding contacts change the number of brushes engaged to extract a greater amount of electrical energy from the spinning cone 401 . In an embodiment of the invention, once the cone has moved completely to the end of the structure where it cannot accept more wind due to maximum internal cone wind pressure, the cone will activate a mechanism, in a spring loaded fashion, that will disengage the isometric designed unit from its current wind-directional fixed position on its tower. This will allow the unit to turn from front-to-back, reversing itself, and preserving the unit from component damage. While it is in its reversed position, the existing wind pressure will add constant pressure to the safety cone, which will keep the motor disengaged until the internal wind pressure normalizes. However, when the wind subsides enough, it will release a pin in the yaw system's motor allowing the motor to engage the gears and move the unit toward a current angle based on the received wind direction information.
[0027] Because it is the rotational energy of the cone 401 that is converted to energy, an increase in the rotational energy available at a given rotation speed will also allow greater energy to be stored in and retrieved from the cone 401 . In this regard, FIG. 5 shows a weight redistribution system for automatically increasing the rotational moment of the wind turbine cone to increase the rotational energy of the system. The system may be mechanically or electrically automated, and the illustrated system is of the former variety.
[0028] In this embodiment, the rear of the cone 501 includes a plurality of tubular chambers 503 which rotate with the cone 501 . Although two such chambers 503 are shown due to the cross-sectional nature of the drawing, a greater number of chambers 503 may be used as desired. In any case however, the chambers 503 should be balanced in size and position so as not to create an off-center axis of rotation.
[0029] Each chamber 503 includes a sealed piston 505 , and a body of oil, hydraulic fluid or other weighting fluid 507 . The oil in the chambers 503 may be drawn from one or more reservoirs 509 via a rotary union or the like. Although not shown, the top of each chamber may be vented to allow free movement of the piston 505 . A spring 511 , placed as shown at the top of the chamber 503 or placed elsewhere in the system and connected directly or hydraulically to the piston 505 , allows the radial position of the piston 505 to increase with increasing cone speed, thus enhancing the rotating weight of the cone 521 .
[0030] As noted above, the turbine assembly shown in the preceding figures is mounted on a framework pedestal, which includes elements for support, rotation, e.g., to match wind direction, and for conveying electrical power generated by the system. In an embodiment of the invention, the support includes or is connected to a wind sensor and a motor, such that the motor rotates the turbine to face most directly into the wind. In this embodiment, if the wind pressure on the turbine exceeds a threshold level indicating that it is reaching a damaging level, the motor will activate to pivot the turbine away from the wind until the wind decreases again to a safe level.
[0031] The structure of the base portion is not critical in every embodiment, but an exemplary structure is shown in FIG. 6 . This FIG. represents a top elevation view of the base tower 600 , showing various supports. In the illustrated example, the tower 600 includes eight external supports 601 and 4 internal supports 603 , with the internal supports 603 being at a steeper angle so as to have ground contact points inside the contact points for the external supports 601 . The external supports 601 are braced in pairs, e.g., by cables 605 , to the internal supports 603 , so as to provide rigidity in all horizontal directions to resist wind loads as well as in the vertical direction to support the weight of the turbine system.
[0032] A platform 607 is located at the top of the tower 600 for supporting the wind turbine system. A system of bearings, not shown, may be included in the platform 607 to support the turbine system and to allow rotation of the turbine about the vertical axis. The tower 600 is shown in side elevation view in FIG. 7 as tower 700 . In this FIG., like numerals refer to like elements in regard to those of FIG. 6 . Thus, the external supports 601 , internal supports 603 , cables 605 , and platform 607 are shown as elements 701 - 707 respectively in FIG. 7 .
[0033] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
[0034] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
[0035] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. | The invention provides a system for capturing moving air and extracting energy from the moving air, the system comprising. A rotor cone is provided having an outer surface, the rotor cone being rotatable about its central axis and having a plurality of veins affixed upon the outer surface of the rotor cone, for receiving a force from the moving air in order to rotate the rotor cone. A shroud surrounds the rotor cone and extends past the narrow end of the cone, opening to an open end having a diameter substantially equal to that of the cone. When moving air enters the shroud at the open end, the moving air compresses within the shroud until it reaches the cone, passes between the cone and the shroud, and impacts the plurality of veins, rotating the cone. A generator within the cone generates electrical energy. In an embodiment, a system is provided for opening the gap between the cone and the shroud under heavy wind to bypass a portion of the moving air. In a further embodiment, a weight redistribution system is provided to increase the rotational inertia of the cone as a function of the rotational speed of the cone. |
TECHNICAL FIELD
[0001] The present invention relates to systems for processing sewage; more particularly, to such systems for handling biologically digestible materials in sewage; and most particularly to methods and apparatus for separating biologically-digestible materials from an influent sewage stream.
BACKGROUND OF THE INVENTION
[0002] The primary historical objective of waste water treatment operations has been to neutralize and otherwise render sewage effluence in compliance with regulatory limits based on environmental and health standards. An important and growing objective of modern waste water treatments is the generation of energy from biologically-digestible organic materials present in the waste water. To achieve this objective, during the treatment of waste water influent streams containing biologically-digestible materials, as part of selectively classifying and separating grits, solids, hair and fibers, particulates, and solvated materials, it is particularly desirable to separate the digestible materials in the influent stream from non-digestible materials such that digestion of the digestible materials can be optimized. For systems that produce sludge in processes downstream from primary clarification (i.e., secondary sludge), it is desirable to extract the remaining biologically-digestible materials present in that sludge. Optimization can include increasing and capturing the bio-gas producing materials; production of energy bearing bio-gasses such as methane, produced by the decomposition of the digestible materials; reducing the frequency with which digesters used to digest the digestible materials need to be taken off line and cleaned; automation of the process for separating the digestible materials in the influent stream for digestion to reduce operating costs; reducing energy consumption-related operating costs; reducing the particle size of organic materials to allow rapid biodegradation and to capture organics prior to conversion to carbon-dioxide and biomass; and reducing the capital costs to build a treatment facility to separate and digest biologically-digestible materials in an influent stream.
[0003] In the prior art, the separation of grit from waste water influent is a long standing problem. Grit adversely impacts equipment reliability and lifespan, and increases operating costs of downstream treatment processes. Consequently, grit separators traditionally are used to remove grit from the influent stream as early in the treatment sequence as possible, preferably prior to primary clarification, or in cases where no primary clarification exists, then prior to secondary treatment. In practice, these devices often perform poorly because they are designed for a specific flow range which often is based on peak flows based on projected increases in population or a specific maximum flow based on storm events or future expansion of flows from new industries, etc. The projected flow range frequently is not reached for a number of reasons, such as unanticipated changes in population; changes in economic conditions of a region causing industries to leave or never develop; increased inflow and infiltration (“I and I”) of water into the treatment system from deteriorating collection systems; and the increase in storm intensities.
[0004] In many treatment plants, in an attempt to provide flow equalization at the head of the plant, variable frequency drives have been added to control the pumps delivering influent to the treatment plants from wet wells used as buffers. The variable frequency drives enable operation of the pumps over a range of pump speeds rather than a single speed with the only control option being to turn them off and on. In practice, these variable frequency drives create large fluctuations in influent velocity that can hinder the performance of the highly velocity-sensitive hydrocyclone grit separators. Due to their poor performance, these velocity sensitive grit separators often fail and/or are left in disrepair, requiring grit to be removed from the influent stream as a component of the sludge formed during the primary-treatment process. Typically, the grit slowly fills the secondary treatment process tanks, contributing to reduced energy content of the primary sludge, increasing the frequency with which digesters and secondary process tanks must be cleaned, and causing wear and tear on the plant equipment.
[0005] Current typical waste water plants capture only thirty to thirty-five percent of the biologically-digestible materials during primary clarification. The remainder of the biologically-digestible materials are typically digested during secondary treatment in an activated sludge process that permits the greenhouse gas (CO 2 ) to escape into the atmosphere.
SUMMARY OF THE INVENTION
[0006] Briefly described, a system in accordance with the present application comprises a method and apparatus for separating biologically digestible materials from an influent sewage stream.
[0007] In one aspect of the present application, a primary clarification tank is used to capture sixty percent or more of the total solids from an influent stream.
[0008] In another aspect of the present application, a sludge classifying press (SCP) is used to isolate and concentrate biologically-digestible materials from sludge formed in a primary clarification tank, releasing valuable organics, such as are found in corn kernels, by fracturing the protective casings.
[0009] In another aspect of the present application, grit is captured in a chamber within the primary clarification tank and isolated from the bulk of the sludge-containing biologically-degradable materials.
[0010] In another aspect of the present application, a grit trap or hydrocyclone is used to remove grit from the sludge prior to classifying the sludge with the SCP.
[0011] In another aspect of the present application, the sludge is thickened after classification and prior to digestion.
[0012] In another aspect of the present application, one or more elements of the process for separating and digesting the biologically-digestible materials in an influent stream is automated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
[0014] FIG. 1 is a schematic drawing of an embodiment of a water treatment plant in accordance with the present application;
[0015] FIG. 2 is a schematic drawing and elevational side view of an Influent Feed System (IFS) used in the embodiment shown in FIG. 1 ;
[0016] FIG. 3 is a detailed plan view of one IFS shown in FIG. 1 ;
[0017] FIG. 4 is a schematic drawing of a prior art primary treatment system suitable for use as a first stage in the present application to collect suspended and solvated BOD;
[0018] FIG. 5 is a schematic drawing and elevational end view of one embodiment of a clarification tank and IFS in fluid communication with apparatus to treat grit and sludge settled in the clarification tank and IFS in accordance with the present application;
[0019] FIG. 6 is a schematic elevational drawing of a grit separator in accordance with the present application;
[0020] FIG. 7 is a schematic drawing and plan view of an alternative embodiment of a clarification tank and IFS in fluid communication with apparatus to treat grit and sludge settled in the clarification tank and IFS in accordance with the present application;
[0021] FIG. 8 is a schematic drawing and plan view of another alternative embodiment of a clarification tank and IFS in fluid communication with apparatus to treat grit and sludge settled in the clarification tank and IFS in accordance with the present application;
[0022] FIG. 9 is a schematic drawing and plan view of another alternative embodiment of a clarification tank and IFS in fluid communication with apparatus to treat grit and sludge settled in the clarification tank and IFS in accordance with the present application;
[0023] FIG. 10 is an alternative embodiment of an IFS with separate discharge pipes for removing materials from the IFS troughs and grit box;
[0024] FIG. 11 is a schematic drawing and side elevational view of an IFS arranged to discharge grit and sludge in accordance with the present application; and
[0025] FIG. 12 is a schematic drawing and plan view of an adaptive system for treatment of sludge and grit in accordance with the present application.
[0026] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate currently preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] U.S. Pat. No. 7,972,505, PRIMARY EQUALIZATION SETTLING TANK, to Wright; U.S. Pat. No. 8,225,942 to Wright, SELF-CLEANING INFLUENT FEED SYSTEM FOR A WASTEWATER TREATMENT PLANT; U.S. Pat. No. 8,398,864 SCREENED DECANTER ASSEMBLY FOR A SETTLING TANK to Wright; co-pending U.S. patent application Ser. No. 14/142,197 METHOD AND APPARATUS FOR A VERTICAL LIFT DECANTER SYSTEM IN A WATER TREATMENT SYSTEM by Wright; co-pending U.S. patent application Ser. No. 14/142,099 FLOATABLES AND SCUM REMOVAL APPARATUS FOR A WASTE WATER TREATMENT SYSTEM by Wright, and co-pending U.S. patent application Ser. No. 14/325,421 IFS AND GRIT BOX FOR WATER CLARIFICATION SYSTEMS by Wright (the '421 application), all of which are incorporated by reference in their entirety for all purposes, disclose systems and processes for primary clarification that remove substantially all grit, solids, and particulates larger than 50 microns during primary clarification.
[0000] Separation of Biologically Digestible Materials from the Influent Stream
[0028] FIG. 1 shows a block diagram of one exemplary embodiment of a clarification system 1 configured to separate biologically-digestible materials from an influent stream. In one embodiment, the influent enters the clarification system 1 via pipes 11 where it is stored in wet well 12 . A settling tank 30 is in fluid communication with eight IFS's, 100 - 107 . Pump 13 pumps influent from wet well 12 to IFS's 100 - 107 at a substantially constant flow rate via piping 14 , 15 and 15 ′. In one embodiment, pump 13 operates under the control of a supervisory control and data acquisition system (SCADA) 900 in communication with pump 13 via communication channel 901 . In one embodiment, the SCADA 900 turns pump 13 in response to an indication of wet well 12 fluid level reaching an upper limit, the indication provided by sensor 18 in communication with SCADA 900 via communication channel 907 . In one embodiment, SCADA 900 turns pump 13 off in response to an indication of wet well 12 fluid level reaching a lower limit, the indication provided by sensor 19 in communication with SCADA 900 via communication channel 908 . In an alternative embodiment, SCADA 900 turns pump 13 off after a pre-determined period of time. In an alternate embodiment, SCADA 900 turns pump 13 off after a predetermined volume of fluid has been pumped as indicated by measuring the flow via signals provided by flow meter 25 in communication with SCADA 900 via communication channel 909 . Flow meters and sensors to measure fluid level are well known in the art.
[0029] As is well known in the art, pipes 14 , 15 and 15 ′ are configured to deliver substantially the same flow rate of influent to each IFS 100 - 107 . Flow balancing valves and/or flow splitting may be used. The influent enters the IFS's 100 - 107 where grits, solids, and optionally solvated materials, are selectively classified and separated from the influent via settling and optionally flocculation. Materials settled in the IFS's 100 - 107 are removed via discharge pipes 570 - 577 as described in more detail with reference to FIG. 5 . The influent traverses IFS's 100 - 107 to enter clarification settling tank 30 . As described in the '505 and '864 patents and '197 application, solids remaining in the influent traversing to the clarification settling tank 30 are further classified and separated from the influent via settling. Upon completion of the separation of the solids from the influent, the influent is discharged from the settling tank 30 using screen box assemblies (SBX's) 50 - 54 as described in the '197 application.
[0030] In the embodiment of FIG. 1 , flocculents are optionally added to the influent stream by flocculent delivery systems 40 , 41 . The use of flocculents, for the removal of solids and solvated materials in the treatment of waste water and designs to add flocculents to an influent waste water stream, is well known in the art.
[0031] FIG. 2 shows a side view of an exemplary IFS 100 with IFS troughs and grit box 500 and FIG. 3 shows a top view of the IFS of FIG. 2 , as further described and disclosed in the '421 application. As described in more detail in the '421 application, a mixing zone 504 is created within a grit box 500 at the location where deposition of the floc is desired. With reference to FIG. 2 and FIG. 3 , IFS 100 is configured with a grit box 500 and two IFS troughs 201 , 202 having trough walls 207 , 208 . IFS troughs 201 , 202 are in fluid communication with the grit box 500 . Influent is delivered to IFS 100 via pipe 501 and is split into two streams which enter grit box 500 via pipes 502 , 503 . The streams exit opposing pipes 502 , 503 and collide under pressure to create turbulent mixing zone 504 . A deflector plate 505 is positioned above mixing zone 504 to confine the volume of the mixing zone and return the upward velocities of the streams existing pipes 502 , 503 back into mixing zone 504 . Grit, dense solids, and flocs are deposited in grit box hopper 506 .
[0032] To limit disturbance of solids settling in the lower portion of IFS troughs 201 , 202 in proximity to the grit box 500 , the length of pipes 502 , 503 is arranged to position mixing zone 504 below the lowest portion of IFS troughs 201 , 202 in proximity to and in fluid communication with grit box 500 . Mixing zone 504 and grit box hopper 506 are positioned below the lowest portion 150 , 150 ′ of IFS troughs 201 , 202 in proximity to and in fluid communication with grit box 500 . Solids with a lower settling rate than the designed influent rise velocity in the grit box hopper 506 move into IFS troughs 201 , 202 . Additionally, prior to entering IFS troughs 201 , 202 , solids moving upward under the influence of the rising influent undergo a 90 degree change in direction, turning from vertical to horizontal thus losing inertia and lessening the fluid forces on the suspended grits, solids, and flocs. In one embodiment, as explained in more detail below, grits settle preferentially in grit box 500 .
[0033] Materials that settle in grit box 500 and clarification tank 30 may be removed as part of periodic scouring of grit box 500 and clarification tank 30 or as part of the ongoing operation of clarification system 1 to selectively classify and separate grits, solids, particulates, and solvated materials from an influent stream.
[0034] Other methods may be used to separate and capture large quantities of biologically digestible material from an influent stream. By way of example and not limitation, with reference to FIG. 4 , large quantities of solids, suspended materials, and solvated materials can be rapidly settled from an influent stream by a prior art system such as CLARI-FLOCCULATOR packaged sewage treatment 1100 for primary treatment manufactured by Waterneer, a company with offices in Lidköping Sweden. In the Waterneer primary treatment system, inlet feed pump 1102 is in fluid communication with influent stream 1101 and mixing chamber 1103 . Flocculent source 1106 is in fluid communication with mixing chamber 1103 . Mixing chamber 1103 is in fluid communication with turbulence redirection apparatus 1104 which is in fluid communication with sedimentation chamber 1105 . Sedimentation chamber 1105 further comprises a sludge discharge pipe 1111 , a sensor 1108 in communication with programmable controller 1107 , and valve 1109 under control of and in communication with programmable controller 1107 . Valve 1109 is positioned in sludge discharge pipe to control fluid communication of materials from sedimentation chamber 1109 through sludge discharge pipe 1111 .
[0035] In the Waterneer primary treatment system, inlet feed pump 1102 pumps water from influent stream 1101 into a mixing chamber 1103 where it is mixed with flocculents added to the influent stream by flocculent source 1106 . The influent and flocculent mix is delivered to turbulence redirection apparatus 1104 to slow the velocity of the fluid after which it is delivered to sedimentation chamber 1105 where flocs, grits and other materials settle. Effluent 1110 , free of the settled materials, is evacuated from primary treatment system 1100 . Programmable controller 1106 opens and closes valve 1109 responsive to signals from sensor 1108 indicating that the thickness of the sludge settled in sedimentation chamber 1105 has exceeded a predetermined threshold. Sludge from sedimentation chamber 1105 is evacuated via discharge pipe 1111 .
[0000] Treatment of Materials Separated from the Influent Stream to Concentrate Biologically-Digestible Materials
[0036] With reference to FIGS. 2 and 5 , grit box 500 of IFS 100 is in fluid communication with discharge pipe 570 . Fluid communication via discharge pipe 570 is controlled by valve 580 . Valve 580 may be a manually-operated valve. In an alternate embodiment, valve 580 is electronically controlled by a supervisory control and data acquisition SCADA system 900 which provides a signal via communication channel 919 to open and close valve 580 . SCADA systems and electronically controlled valves are well known in the art.
[0037] With reference to FIG. 5 in one embodiment, IFS 100 , 104 discharge pipes 570 , 574 and clarification tank 30 discharge pipe 70 are in fluid communication with sludge and grit intake pipe 20 which is in fluid communication with sludge pump 50 . Sludge pump 50 is in fluid communication with grit separator 51 via pipe 20 a . Grit separator 51 is in fluid communication with sludge classification press 52 via pipe 20 b . Sludge classification press 52 is in fluid communication with optional sludge thickener 53 via pipe 20 c . Sludge thickener 53 is in fluid communication with pipe 20 d . Optionally, a flocculent source 55 a is arranged to communicate flocculents to sludge prior to treatment by sludge classification press 52 . Optionally, a flocculent source 55 b is arranged to communicate flocculents to the sludge discharged by sludge classification press 52 . In one embodiment, sludge pump 50 is in communication with and controlled by SCADA 900 via communication channel 926 . In one embodiment, classification press 52 is in communication with and controlled by SCADA 900 via communication channel 927 . In one embodiment, flocculent sources 55 a , 55 b are in communication with and controlled by SCADA 900 via communication channels 929 a , 929 b . In one embodiment, sludge thickener 53 is in communication with and controlled by SCADA 900 via communication channel 928 .
[0038] In one embodiment, one or more optional flowmeters are incorporated in the system: flow meter 5701 to measure the flow in discharge pipe 570 ; flow meter 5741 to measure the flow in discharge pipe 574 ; flow meter 7001 to measure the flow in discharge pipe 70 ; flow meter 2001 to measure the flow in pipe 20 a ; flow meter 2003 to measure the flow in discharge pipe 20 b ; flow meter 2005 to measure the flow in pipe 20 c ; and flow meter 2007 to measure the flow in pipe 20 d.
[0039] In one embodiment, flow meter 5701 is in communication with SCADA 900 via communication channel 917 . In one embodiment, flow meter 5741 is in communication with SCADA 900 via communication channel 920 . In one embodiment flow meter 7001 is in communication with SCADA 900 via communication channel 923 . In one embodiment, flow meter 2001 is in communication with SCADA 900 via communication channel 936 . In one embodiment, flow meter 2003 is in communication with SCADA 900 via communication channel 938 . In one embodiment, flow meter 2005 is in communication with SCADA 900 via communication channel 940 . In one embodiment, flow meter 2007 is in communication with SCADA 900 via communication channel 942 .
[0040] In one embodiment, one or more optional sensors are incorporated in the system: sensor 5702 to measure the characteristics of materials in discharge pipe 570 ; sensor 5742 to measure the characteristics of materials in discharge pipe 574 ; sensor 7002 to measure the characteristics of materials in discharge pipe 70 ; sensor 2002 to measure the characteristics of materials in discharge pipe 20 a ; sensor 2004 to measure the characteristics of materials in discharge pipe 20 b ; sensor 2006 to measure the characteristics of materials in discharge pipe 20 c ; and, sensor 2008 to measure the characteristics of materials in discharge pipe 20 d . The optional sensors are in communication with SCADA 900 : sensor 5702 via communication channel 918 ; sensor 5742 via communication channel 921 ; sensor 7002 via communication channel 924 ; sensor 2002 via communication channel 937 ; sensor 2004 via communication channel 939 ; sensor 2006 via communication channel 941 ; and sensor 2008 via communication channel 943 .
[0041] Sensors 5702 5742 , 7002 , 2004 , 2006 , and 2008 may be a UVAS sensor, turbidity sensor, pH sensor, or any other type of sensor consistent with measuring the physical and/or chemical characteristics of sludge and grits undergoing treatment.
[0042] With reference to FIG. 5 , sludge 1000 settled in grit box 500 of IFS 100 can be removed via discharge pipe 70 . With reference to the exemplary embodiment of FIG. 2 , in one embodiment valve 580 is opened and fluid is pumped or gravity fed through pipes 410 , 415 to scour the IFS troughs and grit box. In an alternative method for evacuating and scouring the IFS, valve 580 is opened and IFS troughs 201 , 202 are scoured with liquid to evacuate solids from the entirety of the IFS. In one embodiment, as part of the ongoing operation of the clarification system 1 of FIG. 1 , to selectively classify and separate grits, solids, particulates, and solvated materials from an influent stream, valve 580 is opened to remove the settled materials without concurrent scouring of the IFS.
[0043] With reference to FIG. 5 , sludge 1000 settled in grit box 500 may have viscosity low enough to flow from the grit box under the influence of gravity. The solids content of the sludge is dependent on the type of solids, the depth of the tank, the methodology of extraction, and how long the sludge is resident in the tank prior to extraction. A representative range for the solids content of materials 1010 is from less than one-tenth of a percent to five percent or more. The head pressure from the influent in IFS 100 may be used to assist in moving sludge 1000 in grit box 500 through discharge pipe 570 . In one embodiment, sludge pump 50 is used to assist in the evacuation of materials 1000 settled in grit box 500 . In one embodiment, sludge pump 50 is electronically controlled by a supervisory control and data acquisition system SCADA 900 which provides a signal via communication channel 926 to start and stop pumping.
[0044] With reference to FIG. 5 , sludge 1010 settled in clarification tank 30 can be removed via discharge pipe 70 in liquid communication with the clarification tank 30 . Fluid communication via discharge pipe 70 is controlled by valve 80 . Sludge 1010 settled in clarification tank 30 can be removed by scouring and cleaning with a fluid as described for example in the '864 patent. In one embodiment, as part of the ongoing operation of clarification system 1 of FIG. 1 , to selectively classify and separate grits, solids, particulates, and solvated materials from an influent stream, valve 80 is opened to remove the settled materials.
[0045] Sludge 1010 , settled in clarification tank 30 may have viscosity low enough to flow from clarification tank 30 under the influence of gravity. The solids content of the sludge is dependent on the type of solids, the depth of the tank, the methodology of extraction, and how long the sludge is resident in the tank prior to extraction. A representative range for the solids content of materials 1010 is from less than one-tenth of a percent to five percent or more. The head pressure from the influent in clarification tank 30 may be used to assist in moving sludge 1010 in the clarification tank 30 through discharge pipe 70 . In one embodiment, a sludge pump 50 is used to assist in the evacuation of sludge 1010 settled in clarification tank 30 .
[0046] Sludge from IFS 100 , 104 and clarification tank 30 enters grit separator 51 which separates and removes coarse, dense solids, referred to herein as “grit” or “grits”, that are not biologically digestible from the sludge. Grit separator 51 may be a gravity separator as shown with reference to FIG. 6 or a hydro-cyclone as is well known in the art. The removal of grits from the sludge removed from clarification tank 30 and IFS' 100 - 107 rather than from the influent stream prior to primary clarification provides for improved operation of the grit separator and overall plant reliability.
[0047] With reference to FIG. 6 , there is shown one embodiment of a grit separator 51 that is a gravity separator 1200 in accordance with the current invention. Gravity separator 1200 has an influent pipe 1201 in fluid communication with a gravity separation chamber 1202 . Gravity separation chamber 1202 is in fluid communication with grit discharge pipe 1203 and sludge discharge pipe 1204 . Valve 1205 is positioned on grit discharge pipe 1203 and controls fluid communication through pipe 1203 . Influent pipe 1201 is arranged to have dimensions perpendicular to the flow of influent sludge substantially larger than the dimensions perpendicular to the flow of influent sludge of pipes providing a source of sludge to be treated for removal of grit. Influent pipe 1201 is arranged to provide a downward direction to the flow of fluids and materials as they enter gravity separation chamber 1202 giving dense solids inertia downward to gently agitate settled solids and to re-suspend any low density organic materials. The bottom of gravity separation chamber 1202 is designed to slope down to grit discharge pipe 1203 to facilitate discharge of grit under the influence of gravity.
[0048] In operation, sludge enters gravity separator 1200 from a source such as clarification tank 30 of FIG. 5 via pipe 20 a as shown with respect to FIG. 5 . The substantially larger dimensions of influent pipe 1201 relative to source pipe 20 a in the direction perpendicular to the direction of sludge flow results in a rapid and substantial decrease in sludge flow velocity. The dimensions of gravity chamber 1202 are arranged to provide time for grit to settle in the gravity chamber prior to discharge of the sludge. Periodically valve 1205 is opened to remove accumulated grit from gravity separation chamber 1202 . Preferably, valve 1205 is a pinch valve to avoid fouling and failure associated with grit becoming lodged in a valve seat.
[0049] With reference to FIG. 5 , sludge substantially free from grit exits the grit separator and is fluidly communicated to sludge classification press via pipe 20 b . The sludge classification press 52 may be a rotary screw press such as the Strainpress® Sludgecleaner SP manufactured by Huber Technology. In one embodiment, sludge classification press 52 removes all solids larger than 1.6 mm from the sludge. In alternate embodiments, the sludge classification press 52 removes solids with dimensions that range from 0.15 mm to 10 mm. In one embodiment the compression and sheering of the sludge by the sludge classification press 51 releases biologically-digestible material from items such as corn kernels while removing the indigestible or less rapidly digestible materials such as the outer layer of a corn kernel.
[0050] After treatment with sludge classification press 52 , the solids content of the sludge consists primarily of biologically-digestible materials that can be digested in a digester to produce energy-rich bio-gases such as methane. The removal of materials that are not biologically digestible increases the rate of digestion of the remaining materials, enabling greater throughput and processing of sludge by a digester. The removal of non-digestible materials reduces the frequency with which digesters need to be taken off line and cleaned.
[0051] In some applications, it may be desirable to increase the concentration of biologically-digestible material in the sludge after treatment by the sludge classification press 52 and prior to digestion to improve the efficiency of digestion, maintain a low hydraulic retention rate (HRT), and increase the volume of production of bio-gases, such as, by way of example and not limitation, methane. Optionally, a flocculent may be added to the sludge via flocculent source 55 after treatment of the sludge by sludge classification press 52 . The flocculent is added to the sludge to create flocs from dissolved and suspended biologically-digestible materials, thereby increasing the concentration of biologically-digestible materials to improve performance of the digesters that digest the resultant sludge. By way of example, in a municipal waste water treatment plant a representative range for the total solids content the sludge after treatment by sludge classification press 52 is between two and three percent, whereas a digester may operate more efficiently with a total solids content of five to seven percent, and some as much as ten percent or more, depending upon the type of digester. Current systems use total solids as a surrogate measure for the concentration of biologically-digestible organic material in sludge. Gas production comes from volatile solids (VS) which are approximately 70-80% percent of the total solids. In one embodiment of the system, the treated sludge from the sludge classification press is fluidly communicated to solids concentrator 53 via pipe 20 c . Devices to increase solids content of sludge are well known in the art. By way of example and not limitation, solids concentrator 53 may comprise a gravity deck thickener, rotary drum thickener, or a rotary screw press. Sludge thickener 53 increases the solids content of the sludge treated by sludge classification press 52 .
[0052] With reference to FIG. 7 , in one embodiment IFS 100 - 107 discharge pipes 570 - 577 and clarification tank 30 discharge pipe 70 are in fluid communication with sludge and grit intake pipe 20 which is in fluid communication with sludge pump 50 . Sludge Pump 50 is in fluid communication with grit separator 51 via pipe 20 a . Grit separator 51 is in fluid communication with sludge classification press 52 via pipe 20 b . In one embodiment, sludge classification press 52 is in fluid communication with optional sludge thickener 53 via pipe 20 c . Optionally, a flocculent source 55 is arranged to communicate flocculents to sludge traversing pipe 20 c . Optional sludge thickener 53 is in fluid communication with digester 54 via pipe 20 d and wet well 12 of FIG. 1 via pipe 22 . In one embodiment, sludge pump 50 is in communication with and controlled by SCADA 900 via communication channel 926 . In one embodiment, sludge pump 52 is in communication with and controlled by SCADA 900 via communication channel 926 . In one embodiment, flocculent source 55 is in communication with and controlled by SCADA 900 via communication channel 929 . In one embodiment, sludge thickener 53 is in communication with and controlled by SCADA 55 via communication channel 928 .
[0053] In one embodiment, sludge classification press (SCP) 52 is in fluid communication with digester 54 via pipe 20 c.
[0054] In one embodiment, digester 54 is an anaerobic digester. Sensor 64 is arranged to measure aspects of the operation of digester 54 . Sensor 64 is in communication with SCADA 900 via communication channel 944 . Sensor 64 may be one or more of temperature sensors, carbon-dioxide sensors, oxygen sensor, pH sensor, methane sensor, or any other sensor suitable for measuring the physical condition and characteristics, and chemical properties of the materials undergoing digestion.
[0055] To optimize overall operations of the system and to detect indications of existing or imminent component or system failure, in one embodiment the characteristics of the sludge are measured by sensor 64 as the sludge is treated. Bacteria in an anaerobic digester thrive best when supplied with food at constant concentration and flow rate. If the rate of organics of solid being supplied to the digester 54 goes outside of the desired ranges as measured by one or more sensors 60 , 61 , 62 , SCADA 900 adjusts the throughput of the sludge classification press 52 as needed. If the organics/solids ratios are too low, as measured by one or more sensors 60 , 61 , 62 , SCADA 900 increases the dosage supplied by flocculent source 55 . If the organics/solids ratios are too high, as measured by one or more sensors 60 , 61 , 62 , SCADA 900 decreases or stops the dosage supplied by flocculent source 55 . In one embodiment, as single sampling well and set of sensors are used to minimize cost associated with sensors and simplify issues of cross-sensor calibration and correlation across multiple sensors deployed throughout the system.
[0056] Sampling pump 56 is in fluid communication with pipes 20 a - 20 d via pipe 21 . Sampling pump 56 is preferably a positive displacement pump such as a diaphragm pump or progressive cavity pump in order to prevent fouling. Valves 7 a - 7 d control fluid communication between pipes 20 a - 20 d and pipe 21 . In one embodiment, valves 20 a - 20 d are manually operated. In one embodiment, valves 20 a - 20 d are controlled by and in communication with SCADA 900 via communication channels 935 a - 935 d . In one embodiment, sampling pump 56 is controlled by and in communication with SCADA via communication channel 931 . Sampling pump 56 is in fluid communication with sampling well 57 via pipe 21 . One or more sensors 60 , 61 , 62 are arranged in sampling well 57 to measure various characteristics of materials in sampling well 57 . The one or more sensors are controlled by and in communication with SCADA 900 via communication channels 932 , 933 , 934 . Sampling well 23 is in fluid communication with wet well 12 of FIG. 1 via pipe 23 .
[0057] Sludge from IFS 100 - 107 and clarification tank 30 is treated in a substantially similar manner by sludge pump 50 , sludge classification press 52 , solids concentrator 53 , and flocculent source 55 as described hereinabove with respect to FIG. 5 . Upon final treatment of the sludge by sludge classification press 52 , or optional sludge thickener 53 , as applicable, the sludge is fluidly communicated to digester 54 .
[0058] Sludge removed from IFS 100 - 107 and clarification tank 30 is sampled as it is discharged from sludge pump 50 via pipe 20 a . In one embodiment, SCADA 900 closes valves 7 b , 7 c , 7 d , opens valve 7 a and turns sampling pump 56 on to withdraw sludge via pipe 21 . Sludge is pumped via sampling pump 21 to sampling well 57 where one or more sludge characteristics are measured via one or more sensor 60 , 61 , 62 . Upon completion of the measurements, the sludge sample is discharged via discharge pipe 23 . In a similar manner, one or more characteristics of grit-free sludge are sampled as the sludge is discharged from grit separator 51 via pipe 20 b . In one embodiment, SCADA 900 closes valves 7 a , 7 c , 7 d , opens valve 7 b , and turns sampling pump 56 on to withdraw sludge via pipe 21 . Sludge is pumped via sampling pump 21 to sampling well 57 where sludge characteristics are measured via one or more sensors 60 , 61 , 62 . Upon completion of the measurements, the sludge sample is discharged via discharge pipe 23 . One or more characteristics of classified sludge are measured as the sludge is discharged from sludge classification press 52 via pipe 20 c . In one embodiment, SCADA 900 closes valves 7 a , 7 b , 7 d , opens valve 7 c and turns sampling pump 56 on to withdraw sludge via pipe 21 . Sludge is pumped via sampling pump 21 to sampling well 57 where one or more sludge characteristics are measured via one or more sensors 60 , 61 , 62 . Upon completion of the measurements, the sludge sample is discharged via discharge pipe 23 . One or more characteristics of concentrated sludge are measured as the sludge is discharged from solids concentrator 53 via pipe 20 d . In one embodiment SCADA 900 closes valves 7 a , 7 b , 7 c , opens valve 7 d , and turns sampling pump 56 on to withdraw sludge via pipe 21 . Sludge is pumped via sampling pump 21 to sampling well 57 where one or more sludge characteristics are measured via one or more sensor 60 , 61 , 62 . Upon completion of the measurements, the sludge sample is discharged via discharge pipe 23 .
[0059] In an alternate embodiment, and with reference to FIG. 8 , only the sludge from IFS' 100 - 107 is treated by a grit separator as the sludge in clarification tank 30 is substantially free of grits and other dense solids. IFS 100 - 107 discharge pipes 570 - 577 are in fluid communication with sludge processing intake pipe 20 ′ and sludge pump 50 ′. Sludge pump 50 ′ is in fluid communication with grit separator 51 via pipe 20 f . Grit separator 51 is in fluid communication with sludge classification press 52 via pipe 20 g . Clarification tank 30 discharge pipe 70 is in fluid communication with sludge pump 50 . Sludge pump 50 is in fluid communication with grit separator 51 via pipe 20 e.
[0060] In an alternate embodiment and with reference to FIG. 9 , the content of biologically-digestible materials in sludge from the IFS' 100 - 107 is insignificant relative to the cost of extraction from the sludge. IFS 100 - 107 discharge pipes 570 - 577 are in fluid communication with sludge processing intake pipe 20 ′ and sludge pump 50 ′. Sludge pump 50 ′ is in fluid communication with grit separator 51 via pipe 20 f . Grit separator 51 separates the grits and particulates from the liquid. Liquid and non-particulate, non-grit sludge extracted from the sludge by grit separator 51 are returned to wet well 12 of FIG. 1 via discharge pipe 26 , and grit is disposed of in a landfill or by other means.
[0061] In another alternate embodiment, and with reference to FIG. 10 where substantive biologically-degradable material settles in IFS 100 IFS troughs 201 , 202 , but not in IFS 100 grit box 500 , IFS trough 201 , 202 discharge pipes 271 , 272 may be arranged to be in fluid communication with sludge process intake pipe 20 in communication with sludge pump 50 while grit box discharge pipe 570 is arrange to be in fluid communication with sludge processing intake pipe 20 ′ in fluid communication with sludge pump 51 ′ for further treatment, as shown by way of example and not limitation in FIG. 8 and FIG. 9 .
[0062] In a waste water treatment plant, the composition of the sludge settled in the IFS troughs, grit box, and clarification tank can change over time as a result of variations in the composition of the influent, changes in plant operating conditions, and other factors such as temperature and relative humidity. With reference to FIG. 11 , to provide flexibility in the treatment of sludge from clarification tank 30 , if the sludge has substantially no grit, discharge pipe 70 may be placed in fluid communication with sludge pump 50 by opening valve 36 and closing valve 35 , resulting in the sludge bypassing grit separator 51 . Check valve 47 prevents the sludge in discharge pipe 70 from entering sludge and grit intake pipe 20 ′ via pipe 20 i . Alternatively, if there is a need to separate grit from sludge in clarification tank 30 , discharge pipe 70 is placed in fluid communication with sludge pump 50 ′ by opening valve 35 and closing valve 36 . Check valve 49 prevents sludge from clarification tank 30 flowing into IFS' 100 - 107 via sludge and grit intake pipe 20 ′. Similarly, to provide flexibility in the treatment of sludge from IFS' 100 - 107 , if the sludge has substantially no grit, sludge and grit intake pipe 20 ′ may be placed in fluid communication with sludge pump 50 by opening valve 37 and closing valve 38 , resulting in the sludge bypassing grit separator 51 . Check valve 46 prevents the sludge from IFS' 100 - 107 flowing back into clarification tank 30 via discharge pipe 70 . Alternatively, if there is a need to separate grit from sludge in the IFS' 100 - 107 , sludge and intake pipe 20 ′ is placed in fluid communication with sludge pump 50 ′ by opening valve 38 and closing valve 37 . Check valve 48 prevents sludge from IFS' 100 - 107 flowing into clarification tank 30 via discharge pipe 70 .
[0063] Similarly, in a waste water treatment plant the amount of biologically-degradable material associated with sludge processed by grit separator 51 may change over time as a result of variations in the composition of the influent, changes in plant operating conditions and other factors such as flows from precipitation, snow melt, industrial discharges, and significant public events such as a surge in the use of toilets during Super Bowl halftime.
[0064] With reference to FIG. 9 , IFS 100 - 107 discharge pipes 570 - 577 are in fluid communication with sludge and sludge intake pipe 20 ′ which is in fluid communication with sludge pump 50 ′. IFS 100 - 107 discharge pipes 570 - 577 are in fluid communication sludge pump 50 via sludge and intake pipe 20 ′ which is in fluid communication with pipe 20 i which is in fluid communication with clarification tank 30 discharge pipe 70 which is in direct fluid communication with sludge pump 50 . Valve 38 is positioned in pipe 20 ′ to control the flow of materials from discharge pipes 570 - 577 to sludge pump 50 ′ and not to affect the fluid communication of materials between discharge pipes 570 - 577 and sludge pump 50 and between clarification tank 30 discharge pipe 70 and sludge pump 50 as described hereinbelow. Valve 37 is positioned in pipe 20 i to control the flow of materials from IFS 100 - 107 discharge pipes 570 - 577 to sludge pump 50 . Valve 37 and pipe 20 i are arrange to have no effect on the fluid communication between clarification tank 30 ′ discharge pipe 70 and sludge pump 50 and between clarification tank 30 discharge pipe 70 and sludge pump 50 ′.
[0065] Valve 36 is positioned to control the flow of materials in discharge pipe 70 to sludge pump 50 and to have no effect on the fluid communication of materials between pipe 20 ′ and sludge pump 50 ′ or on the fluid communication of materials between discharge pipe 70 and sludge pump 50 .
[0066] Clarification tank 30 discharge pipe 70 is in fluid communication with sludge pump 50 . Clarification tank 30 discharge pipe 70 is in fluid communication with sludge pump 50 ′ via pipe 20 h which is communication with pipe 20 ′. Valve 36 is positioned in discharge pipe 70 to control the fluid communication of materials in discharge pipe 70 with sludge pump 50 and to have no effect on the fluid communication between materials in discharge pipe 70 and sludge pump 50 ′ and to have no effect on fluid communication of materials in discharge pipes 570 - 577 and sludge pump 50 . Valve 35 is positioned in pipe 20 h to control the fluid communication of materials in discharge pipe 70 to sludge pump 50 ′ and to have no effect on the fluid communication of materials between discharge pipe 70 and sludge pump 50 . Valve 35 and pipe 20 h are positioned so as to have no effect on the fluid communication between materials in discharge pipes 570 - 577 and sludge pump 50 ′ via pipe 20 ′.
[0067] Flap valve 46 is positioned in discharge pipe 70 between clarification tank and valves 35 , 36 to prevent the reverse flow of materials in discharge pipe 70 when valves 35 or 36 are opened, preventing the fluid communication of materials between clarification tank 30 and IFS 100 - 107 . Flap valve 47 is positioned in pipe 20 i to prevent the reverse flow of materials through pipe 20 i when valve 37 is opened, preventing the fluid communication of materials from clarification 30 discharge pipe 70 with sludge pump 50 ′ and IFS troughs 100 - 107 via pipe 20 i . Flap valve 48 is positioned in pipe 20 h to prevent the reverse flow of materials through pipe 20 h when valve 35 is opened, preventing the fluid communication of materials from IFS troughs 100 - 107 with clarification tank 30 and sludge pump 50 via pipe 20 h . Flap valve 49 is positioned in grit and sludge intake valve 20 ′ to prevent the reverse flow of materials in sludge and intake pipe 20 ′, preventing fluid communication of materials from clarification tank 30 and IFS troughs 100 - 107 .
[0068] Sludge pump 50 is in fluid communication with sludge classification press 52 via pipe 20 e . Sludge pump 50 ′ is in communication with grit separator 51 via pipe 20 f . Grit separator 51 discharges grit-free sludge via pipe 20 g and is in communication with sludge classification press 52 via pipe 20 g . Alternatively grit separator 51 discharges grit-free pipe via pipe 26 and is in fluid communication with wet well 12 of FIG. 1 via pipe 26 . Grit Separator 51 discharges grit via discharge pipe 24 . Valve 39 is positioned on pipe 20 g to control fluid communication between grit separator 51 and sludge classification press 52 . Valve 43 is positioned on pipe 26 to control fluid communication between grit separator 51 and wet well 12 of FIG. 1 .
[0069] Sludge classification press 52 is in fluid communication with optional sludge thickener 53 via pipe 20 c . Optional solids concentrator 53 is in fluid communication with digester 54 via pipe 20 d . In one embodiment, sludge thickener is in direct fluid communication with digester 54 via pipe 20 c.
[0070] Valves 35 - 39 may be manually operated valves. In one embodiment, valves 35 - 39 are electronically-controlled valves under control of and in communication with SCADA 900 via communication channels 945 - 949 respectively. Valves 43 may be a manually operated valve. In one embodiment, valve 43 is an electronically-controlled valve under control of and in communication with SCADA 900 via communication channel 950 .
[0071] With reference to FIG. 11 , to provide flexibility in the treatment of sludge processed by grit separator 51 , if the sludge has substantially no biologically-degradable materials, valve 39 providing fluid communication between grit separator 51 and sludge classification press 52 remains closed. Valve 43 is opened and liquid and non-particulate, non-grit sludge extracted from the sludge by the grit separator 51 is returned to wet well 12 of FIG. 1 via discharge pipe 26 and grit is disposed of in a landfill or by other means. If the sludge has substantive biologically-degradable materials, valve 39 providing fluid communication between grit separator 51 and sludge classification press 52 is opened and valve 43 is closed. Liquid and non-particulate, non-grit sludge extracted from the sludge by the grit separator 51 is then treated by sludge classification press 52 and grit is disposed of in a landfill or by other means.
[0072] In one embodiment of the current application, sludge and grit that has not otherwise been separated into components by a primary treatment system is treated to remove grits and other undesirable materials and to separate and concentrate biologically digestible materials. With reference to FIG. 4 , discharge pipe 1111 of primary treatment system 1100 is in fluid communication with sludge and grit intake pipe 20 of FIG. 12 . In one embodiment, a sludge pump 50 is used to assist in the evacuation of the primary treatment system 1100 sludge. In one embodiment, sludge pump 50 is electronically controlled by a supervisory control and data acquisition system SCADA 900 which provides a signal via communication channel 926 to start and stop pumping.
[0073] A sludge treatment system may receive sludge with varying characteristics during its operation. In a waste water treatment system, the characteristics of the sludge may vary due to seasonal and diurnal variations in the characteristics of the influent as well as from periodic and/or isolated events. A storm may result in flushing of grit and particulates from a sewer system connected to the waste water treatment system. An industrial emitter may periodically discharge low grit materials rich in biologically-digestible materials into a sanitary sewer system connected to a waste water treatment plant. Clarification systems such as the prior art CLARI-FLOCCULATOR® system of FIG. 4 may be used to treat sites containing waste water that are remote or otherwise not directly connected to a waste water treatment system. In these circumstances, the sludge produced by treatment of the waste water may need to be transported to a sludge treatment system. It may be desirable to regularly or periodically treat secondary sludge to remove biologically-digestible materials as well as primary sludge. A waste treatment plant may accept food and other wastes with an exceptionally high proportion of biologically-digestible material trucked or otherwise transported directly to the plant. For these and other reasons, it is desirable to have an adaptive, configurable sludge treatment system.
[0074] With reference to FIG. 12 , in one embodiment of the current application, sludge enters grit intake pipe 20 which is in fluid communication with sludge pump 50 . Sludge pump 50 is in fluid communication with grit separator 51 via pipe 20 a . Valve 66 is arranged in line with pipe 20 a to control fluid communication to grit separator 51 . Grit separator 51 is in fluid communication with sludge classification press 52 via pipe 20 b . Valve 84 is arranged in line with pipe 20 b to control fluid communication to sludge classification press 52 . Sludge classification press 52 is in fluid communication with sludge thickener 53 via pipe 20 c . Valve 86 is arranged in line with pipe 20 c to control fluid communication to sludge thickener 53 . Sludge thickener 53 is in fluid communication with digester 54 via pipe 20 d . A flocculent source 55 is arranged to communicate flocculents to sludge prior to being treated by sludge classification press 52 via pipe 27 a or alternatively to sludge discharged from sludge classification press 52 via pipe 27 b . In one embodiment, sludge pump 50 is in communication with and controlled by SCADA 900 via communication channel 926 . In one embodiment, sludge classification press 52 is in communication with and controlled by SCADA 900 via communication channel 927 . In one embodiment, flocculent source 55 is in communication with and controlled by SCADA 900 via communication channel 929 . In one embodiment, sludge thickener 53 is in communication with and controlled by SCADA 900 via communication channel 928 .
[0075] In one embodiment, one or more optional flowmeters are incorporated in the system: flow meter 2009 to measure the flow in discharge pipe 20 ; flow meter 2001 to measure the flow in pipe 20 a , flow meter 2003 to measure the flow in discharge pipe 20 b ; flow meter 2005 to measure the flow in pipe 20 c ; and flow meter 2007 to measure the flow in pipe 20 d . In one embodiment, flow meter 2009 is in communication with SCADA 900 via communication channel 951 . In one embodiment, flow meter 2001 is in communication with SCADA 900 via communication channel 936 . In one embodiment, flow meter 2003 is in communication with SCADA 900 via communication channel 938 . In one embodiment, flow meter 2005 is in communication with SCADA 900 via communication channel 940 . In one embodiment, flow meter 2007 is in communication with SCADA 900 via communication channel 942 .
[0076] In one embodiment, one or more optional sensors are incorporated in the system: sensor 2010 to measure the characteristics of materials in sludge and grit intake pipe 20 ; sensor 2002 to measure the characteristics of materials in discharge pipe 20 a ; sensor 2004 to measure the characteristics of materials in discharge pipe 20 b ; sensor 2006 to measure the characteristics of materials in discharge pipe 20 c ; and, sensor 2008 to measure the characteristics of materials in discharge pipe 20 d . The optional sensors are in communication with SCADA 900 : sensor 2010 via communication channel 952 ; sensor 2002 via communication channel 937 ; sensor 2004 via communication channel 939 ; sensor 2006 via communication channel 941 ; and sensor 2008 via communication channel 943 .
[0077] Sensors 2010 , 2004 , 2006 , and 2008 may be a UVAS sensor, turbidity sensor, pH sensor or solids sensor or any other sensor consistent with measuring the physical and/or chemical characteristics of sludge and grits undergoing treatment.
[0078] Pipe 20 a is in direct fluid communication with pipes 20 a , 20 b , 20 c , and pipe 20 d via pipe 20 j . Valve 64 controls fluid communication between pipe 20 a and pipe 20 j . Valve 65 controls fluid communication between pipe 20 j and pipe 20 b . Valve 85 controls fluid communication between pipe 20 j and pipe 20 c . Valve 87 controls fluid communication between pipe 20 j and pipe 20 d . Valve 69 controls the communication of grit discharged through grit separator 51 grit discharge pipe 24 . In one embodiment, valves 64 , 65 , 66 , 69 , 84 , 85 , 86 , 87 are manually controlled. In one embodiment, valves 64 , 65 , 66 , 69 , 84 , 85 , 86 , 87 are under the control of and in communication with SCADA 900 : valve 64 via communication channel 953 , valve 65 via communication channel 955 ; valve 66 via communication channel 954 ; valve 69 via communication channel 957 ; valve 84 via communication channel 958 ; valve 85 via communication channel 959 ; valve 86 via communication channel 960 ; and, valve 87 via communication channel 961 .
[0079] Check valve 68 is arranged in line with pipe 20 b to permit flow of fluid from grit separator 51 to sludge classification press 52 and to pipe 20 j where pipe 20 j is in fluid communication with pipe 20 b and while preventing the reverse flow of fluid to grit separator 51 . Check valve 88 is arranged in line with pipe 20 c to permit flow of fluid from sludge classification press 52 to solids concentrator 53 and to pipe 20 j where pipe 20 j is in fluid communication with pipe 20 c while preventing the reverse flow of fluid to sludge classification press 52 . Check valve 89 is arranged in line with pipe 20 d to permit flow of fluid from sludge thickener 53 to digester 54 and to pipe 20 j where pipe 20 j is in fluid communication with pipe 20 d while preventing the reverse flow of fluid to sludge thickener 53 .
[0080] The system of FIG. 12 operates in substantially the same manner as the corresponding elements of FIG. 5 when valves 64 , 65 , 85 and 87 are closed and valves 66 , 84 , 86 and 87 are opened. The system is dynamically configured to optimally and most efficiently separator biological materials from the incoming sludge by a combination of continuous monitoring of the sludge characteristics undergoing treatment and a priori knowledge of the sludge characteristics. By way of example, upon receiving sludge from an industrial beverage or food processing source known to have little grit and high solids content, the sludge treatment system of FIG. 12 may be configured to route material past the grit separator and sludge thickener by closing valves 66 and 84 and opening valves 64 , 65 , 84 , 86 and 87 . Upon receiving sludge known to have a great deal of grit, but little biologically-digestible materials, the sludge treatment system of FIG. 12 may be configured to separate grit from the fluid and discharge both by closing valves 64 , 65 and 84 and opening valve 69 .
[0081] While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims. | A system comprising method and apparatus for separating biologically-digestible materials from an influent sewage stream. The system may comprise a primary clarification tank to capture sixty percent or more of the total solids from an influent stream; a sludge classifying press (SCP) to isolate and concentrate biologically digestible materials from sludge formed in the primary clarification tank, releasing valuable organics, such as are found in corn kernels, by fracturing the protective casings; a grit capture mechanism in a chamber within the primary clarification tank and isolated from the bulk of the sludge containing biologically-degradable materials; a grit trap to remove grit from the sludge prior to classifying the sludge with the SCP; apparatus for adding thickener to the sludge after classification and prior to digestion; and automation of one or more elements of the process for separating and digesting the biologically digestible materials in an influent stream. |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to German Application Number 102011104823.9 filed Jun. 20, 2011 to Michael Lang entitled “Complete Cutting Station and Method for Separating Packaging Units,” currently pending, the entire disclosure of which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The invention relates to a complete cutting station according to the preamble of claim 1 , and to a method for separating packaging units which were produced in a common film composite.
BACKGROUND
[0003] Respective complete cutting stations and methods are known in practice. They are widely used in packaging machines in which packaging units are produced from or with a plastic film, for example, in thermo-forming packaging machines or tray sealers. For reasons of efficiency, packaging units are frequently produced in multiple lanes and multiple rows, i.e., several packaging units are produced both in a row as well as side by side in one operation cycle. These packaging units are attached to each other in a film composite (i.e. in a common foil) because at least one film extends continuously across all packaging units and connects these packaging units to each other. In thermo-forming packaging machines, this is the lower film into which packaging trays are thermoformed. Both in thermo-forming packaging machines as well as in tray sealers, the packaging units are connected to each other by means of a top or lid film which is simultaneously sealed onto a plurality of packaging trays.
[0004] There are basically two different variants of how to separate such packaging units connected to each other in a film composite. In the first variant, a longitudinal cutting device and a transverse cutting device are provided one behind the other in the conveying direction i.e. apart from each other. The transverse cuts between adjacent rows of packaging are usually first applied, i.e. the film composite is severed between adjacent rows. Subsequently, the longitudinal cutting device separates the packaging units of the respective lanes.
[0005] In the second variant, to which also the present invention relates, packaging units are cut or punched out from the film composite in a single process step. This is done by means of a complete cutting tool.
[0006] It can be problematic in using a complete cutting tool in that the packaging units can lose their orientation after separation, such as when falling onto a discharge conveyor. This can make subsequent process steps for the packaging units difficult.
SUMMARY OF THE INVENTION
[0007] It is the object of the invention to improve the separation of packaging units from a common film composite with structurally simple means with regard to facilitated subsequent handling of the packaging units.
[0008] This object is satisfied by a complete cutting station having the features of claim 1 and by a method for separating the packaging units having the features of claim 11 , respectively. Advantageous developments of the invention are disclosed in the dependent claims.
[0009] The complete cutting station according to the invention comprises a conveying system which is provided with a respective head portion for gripping on to a packaging unit. In the invention, the head portions of at least one, but possibly of all conveying elements are movable between a first position in which packaging units that they gripped are at a first distance to each other defined by the film composite, and a second position in which the packaging units are at a second, smaller distance from each other. This second, smaller distance can even be a “negative distance”, meaning that the packaging units at least in one spatial direction at least partially overlap.
[0010] The complete cutting station according to the invention provides various advantages regarding the handling of the packaging units. The conveying system already ensures that the packaging units do not lose their position and orientation during separation. This is because during separation, the packaging units can be held by the head portions of the conveyor elements and be fixed in their position. In addition, the conveying system enables transfer of the separated packaging units from the complete cutting tool, for example, to a subsequent packing station, where a group of packaging units is placed into a common outer packaging unit. But above all, the conveying system in the complete cutting station according to the invention allows for the distance of the packaging units to be reduced or even an overlap between the packaging units is created by means of the conveying system after separation of the packaging units. This makes it possible to accommodate more packaging units in an outer packaging unit of a given size, or a given number of packaging units, to use smaller outer packaging units. This in turn makes subsequent logistics processes more process-reliable, simpler and less expensive. Alternatively, the packaging units could be placed not in an outer packaging unit, but on a discharge belt or the like—here again with the advantage mentioned of saving space and of simplifying logistics.
[0011] Preferably, the conveyor elements are translationally movable and/or pivotable in order to reduce the distance between adjacent packaging units. Both variants are relatively easy to design and provide secure and precise positioning of the packaging units when reducing the distance to each other.
[0012] It is particularly favorable where, in the second position of the head portions of the conveyor elements, there is a partial overlap in two spatial directions of the packaging units gripped by the head portions. A particularly large amount of space is saved when inserting the packaging units into a common packaging unit.
[0013] Conveniently, the conveyor elements are movable between a retracted and an extended position. This allows them to convey packaging units, that are gripped by the head portions, out of the complete cutting tool. The motion between a retracted and an extended position can be either independent of the motion of the conveyor elements reducing the distance between the packaging units, or the motion between the retracted and extended positions of the conveyor elements can be superimposed or occur simultaneously with the motion reducing the distance between adjacent conveyor elements.
[0014] When the head portions of the conveyor elements are in the retracted position between cutting edges of the complete cutting tool, then the complete cutting station can be designed in an extremely compact manner.
[0015] The complete cutting tool can, during operation of the complete cutting station, be positioned above the film composite. This has an advantage in that the space below the separated packaging units remains free, and is thus not occupied in particular by a complete cutting tool. This allows for outer packaging units or a discharge belt to be placed directly underneath the packaging units to be separated, further facilitating the handling of the packaging units.
[0016] In one embodiment, the complete cutting tool comprises a bridge connecting several cutting edges of the tool. Each cutting edge can be provided for separating or punching out a single package. The connection of the cutting edges, by means of a bridge, increases the stability of the cutting edges and thus ensures even more precise, simultaneous separation of several packaging units.
[0017] Beyond that, these bridges offer the option of to have the conveyor elements of the conveying system mounted on them in a pivotal and/or translationally movable manner. This could for example be achieved by pivot bearings or rails.
[0018] In a preferred variant of the invention, the conveyor elements are vacuum grippers and the head portions are suction heads of these vacuum grippers. A vacuum pump can be used to apply a vacuum to the suction heads in order to be able to fix packaging units there.
[0019] The invention also relates to a packaging machine with a complete cutting station of the kind described above. The packaging machine can in particular be a thermo-forming packaging machine or a tray sealer.
[0020] Furthermore, the invention also relates to a method for separating packaging units which were produced in a common film, i.e. a film composite. In this method, the packaging units still being connected in the film composite are gripped by means of a respective head portion of a conveyor element, the packaging units are separated by means of a complete cutting tool separating the film composite, and the head portions of the conveyor elements each gripping a packaging unit are subsequently moved such that the distance between adjacent packaging units is reduced and/or that adjacent packaging units overlap at least partially. This method provides the same advantages as explained above with respect to the complete cutting station according to the invention.
[0021] To enable simple yet accurate positioning of the packaging units, the conveyor elements can pivot and/or move translationally in order to reduce the distances between adjacent packaging units.
[0022] It would also be conceivable that some conveyor elements initially move in a direction perpendicular to a plane of the film composite, before the distances between the head portions of the conveyor elements are reduced. This makes it possible to initially bring a few packaging units to a higher or lower plane than adjacent packaging units. This can facilitate overlapping of the packaging units, since collision of the edges of adjacent packaging units at the same height is avoided. It is in particular conceivable, that along a row and/or a track of packaging units, every other packaging unit is in this manner vertically to the plane of the film composite initially brought into another plane before the distances between adjacent packaging units is reduced or the packaging units are overlapped.
[0023] Particularly simple fixing and releasing of the packaging units can be enabled by having by the head portions of the conveyor elements grip the packaging units by means of suction.
[0024] Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.
DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0025] In the accompanying drawing, which forms a part of the specification and is to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views:
[0026] FIG. 1 shows a schematic view of a packaging machine in the form of a thermo-forming packaging machine in accordance with one embodiment of the present invention;
[0027] FIG. 2 shows an illustration of the main components of a complete cutting station according to the invention in a first state in accordance with one embodiment of the present invention;
[0028] FIG. 3 shows an illustration of the complete cutting station shown in FIG. 2 in a second state in accordance with one embodiment of the present invention;
[0029] FIG. 4 shows an illustration of the complete cutting station shown in FIG. 2 in an altered embodiment in accordance with one embodiment of the present invention;
[0030] FIG. 5 shows a plan view of a group of packaging units during separation in accordance with one embodiment of the present invention; and
[0031] FIG. 6 shows a plan view of the packaging units shown in FIG. 5 after reduction of the distance of adjacent packaging units in accordance with one embodiment of the present invention.
[0032] Identical components are in the figures designated throughout with the same reference numerals.
DETAILED DESCRIPTION OF THE INVENTION
[0033] The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures.
[0034] The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled.
[0035] FIG. 1 shows a schematic view of a packaging machine 1 according to the invention in the form of a thermo-forming packaging machine. This thermo-forming packaging machine 1 comprises a forming station 2 , a sealing station 3 , and a complete cutting station 4 according to the invention, which are arranged in this sequence in a direction of processing R on a machine frame 6 . On the input side, the machine frame 6 has a supply roller 7 disposed on it, from which a film 8 is drawn off. In the region of the sealing station 3 , a material storage 9 is provided, from which a top film 10 is drawn off. Furthermore, the packaging machine 1 comprises a supply device or feed device (not shown) which grips the film 8 in order to transport it with every main processing cycle in the direction of processing R. The supply device can for instance be conveyor chains disposed at both sides of the film 8
[0036] In the illustrated embodiment, the forming station 2 is formed as a thermo-forming station, in which trays 14 are formed in the film 8 by thermo-forming. In this, the forming station 2 may be designed such that several trays can be formed next to one another in the direction perpendicular to the direction of processing R. Following the forming station 2 in the direction of processing R, a filling stretch or loading stretch 15 is provided, in which the trays 14 formed in the film 8 are manually or automatically filled with a product 16 .
[0037] The sealing station 3 has a sealable chamber 17 in which the atmosphere in the packaging trays 14 prior to sealing can, for example by flushing with a gas, be replaced with an exchange gas or a gas mixture. Alternatively, the packaging trays 14 in the sealable chamber 17 can be evacuated.
[0038] At the complete cutting station 4 , the packaging units produced together in one processing cycle of the packaging machine 1 are simultaneously separated. They are simultaneously cut out from the film composite 5 . This film composite 5 results from the lower film 8 and/or the top film 10 , by means of which all packaging units of the group of packaging units are connected. In the complete cutting station, every packaging unit is cut or punched out from the film composite 5 in a single process step.
[0039] The packaging machine 1 further comprises a controller 18 . It has the duty of controlling and monitoring the processes running in the packaging machine 1 . A display device 19 with controls elements 20 is used for visualizing or influencing, respectively, the processes in the packaging machine 1 , or by an operator, respectively.
[0040] The general mode of operation of the packaging machine 1 is described briefly below.
[0041] The lower film 8 is drawn off from the feed roller 7 and transported through a supply device into the forming station 2 . In the forming station 2 , trays 14 are formed in the film 8 by thermo-forming. The trays 14 are together with the surrounding area of the film 8 further transported in one main processing cycle to the filling stretch or loading stretch 15 in which they are filled with the product 16 .
[0042] Then, the filled trays 14 together with the surrounding area of the film 8 are in a further main processing cycle transported by the supply device into the sealing station 3 . The top film 10 is, after a sealing process to the film 8 , further transported with the feeding motion of the film 8 . In this, the top film 10 is drawn off from the material storage 9 . Sealing the top film 10 onto the packaging trays 14 results in closed packaging units 21 , which initially continue to remain connected in a common film composite 5 . This film composite, as explained, is formed from the lower film 8 and the top film 10 . The packaging units 21 are finally separated in the complete cutting station 4 .
[0043] In the region of the complete cutting station 4 , outer packaging units 22 can be provided, for example cardboard boxes, for receiving separated packaging units 21 . FIG. 1 shows a variant in which the outer packaging units 22 are by means of a conveyor element, for example, a conveyor belt 23 , brought to a position below the complete cutting station 4 . There, each outer packaging unit 22 can from the top be filled by means of one or several groups of respectively simultaneously produced and separated packaging units 21 . If the outer packaging unit 22 is filled completely, it is removed by means of the conveyor belt 23 and replaced with a new outer packaging unit 22 .
[0044] FIG. 2 shows a schematic representation of the major components of an embodiment of a complete cutting station 4 according to the invention. This complete cutting station 4 comprises a complete cutting tool 24 , which in turn comprises several cutting edges 25 . Each cutting edge 25 has a shape corresponding to the outer contour of the packaging unit 21 to be produced, i.e. each cutting edge 25 can in one single process step separate a packing unit 21 from the film composite 5 . The outer contour of the packaging unit 21 or the contour of the cutting edge 25 , respectively, is virtually arbitrary. For example, they can be oval, rectangular or square with or without rounded corners, polygonal, circular, etc. The cutting edges 25 are facing downwards, as the complete cutting tool 24 with the complete cutting station 4 according to the invention is located above the film composite 5 .
[0045] The cutting edges 25 are mounted to a bridge 26 that connects all the cutting edges 25 of the tool 24 with each other. The bridge 26 can by means a suitable drive, for example a servomotor, be moved in the vertical direction relative to the film composite 5 , so that the cutting edges 25 severe the film composite 5 and thus separate the packaging units 21 . Adjacent packaging units during separation, as shown in FIG. 2 , have a distance D to each other, which is defined by the position of the packaging units 21 in the film composite 25 or by the arrangement of the cutting edges 25 of the tool 24 .
[0046] The complete cutting station 4 also comprises a gripper or conveying system 27 . The conveying system 27 comprises a plurality of movable conveyor elements 28 , each of which comprises a head portion 29 to be able to fix each individual packaging unit 21 to the conveyor element 28 . Preferably, the conveyor elements 28 are vacuum grippers and the head portions 29 are respective suction heads on these vacuum grippers. If a vacuum is applied to them by a suitable vacuum source, packaging units 21 are fixed to the suction heads 29 applied to them.
[0047] The head portion 29 of each conveyor element 28 has such external dimensions that it can be located fully within the limits of a contour for a particular packaging unit defined by a cutting edge 25 , i.e. does not interfere with the cutting edge 25 . The conveyor elements 28 themselves are essentially rod-shaped and extend in the vertical direction. At its lower end, a conveyor element 28 carries its head portion 29 to which it can fix a packaging unit 21 . In the interior of the rod-like conveyor element 28 , there can be a pneumatic line for applying a negative pressure at the head portion 29 .
[0048] The conveyor elements 28 are in the illustrated embodiment supported at a gripper bridge 260 of the complete cutting station 4 . They are in particular there supported such that they can move in a vertical direction in relation to the complete cutting tool 24 , namely, between a retracted position in which the head portions 29 are located between the cutting edges 25 , and an extended downward position. By being attached to the gripper bridge 260 , the vertical or stroke motion of the conveyor elements 28 is coupled. The vertical motion of the conveyor elements 28 is at least sectionally independent of the vertical motion of the complete cutting tool 24 . The height of the cutting blades 30 comprising the cutting edges 25 , i.e. the distance from the lower end of the cutting edges 25 to the bridge 26 is so large that the head portions 29 of the conveyor elements 28 can be retracted between the cutting blades 30 .
[0049] In addition to the vertical motion between a retracted and an extended position, the conveyor elements 28 can also perform a pivoting motion and/or a lateral translation motion. In order to be able to perform this additional motion, the conveyor elements 28 are provided with suitable actuators or motors.
[0050] FIG. 3 shows a variant of the complete cutting station 4 , in which at least the outer conveyor elements 28 of the conveying system 27 are pivotably supported on the gripper bridge 260 by pivot joints 261 . This allows them to move from the retracted initial position shown in FIG. 2 to the extended position shown in FIG. 3 . Subsequently, the two outer conveyor elements 28 are pivoted (see the two arrows in FIG. 3 ) such that their head portions 29 approach the head portion 29 of the center conveyor element 28 . This causes two things: Firstly, the two outer packaging units 21 take a slanted position due to the pivoting motion of the conveyor elements 28 so that their edges 31 are located above the edge 31 of the center packaging unit 21 . Secondly, the distance D between adjacent packaging units 21 is reduced by the pivoting motion 28 . In the position shown in FIG. 3 , the new distance d between adjacent packaging units 21 is even negative, i.e. the packaging units 21 overlap each other at their edges 31 .
[0051] FIG. 4 shows another variant of a complete cutting station 4 according to the invention. In this variant, the conveyor elements 28 of the conveying system 27 are mounted on a gripper bridge 260 and movable in the vertical direction relative to the complete cutting tool 24 between a retracted and an extended position. FIG. 4 shows the conveyor elements 28 in the extended position. In addition, the conveyor elements 28 , however, are now also movable in the lateral, horizontal direction transversely relative to each other, as again is shown by the two arrows in FIG. 4 . This is true at least for the two outer conveyor elements 28 . They can, after extension of the conveyor elements 28 , move in a horizontal direction along the horizontal guides 262 towards the center conveyor element 28 . In this manner, the distance D between adjacent packaging units 21 is reduced. As shown in FIG. 4 , the new distance d can even be negative, i.e. adjacent packaging units 21 overlap each other. Conveniently, the medium conveyor element 28 is guided along a vertical guide 263 at the gripper bridge 260 further downward than the two outer conveyor elements 28 , so that the edges 31 of adjacent packaging units 21 do not collide with each other.
[0052] FIG. 5 schematically shows a plan view of a group of new packaging units 21 which is produced in three rows and three lanes in a single processing cycle of the packaging machine 1 . Adjacent packaging units 21 have a distance D to each other when they are separated from the common film composite 5 .
[0053] FIG. 6 shows the same nine packaging units 21 after separation of the packaging units 21 and after decreasing the distance between the packaging units by means of the conveying system 27 . The arrows in FIG. 6 indicate in which direction particular packaging units are moved towards each other. It can be seen that the distances D between adjacent packaging units 21 can be reduced in two horizontal spatial directions, until even an overlap between adjacent packaging units 21 occurs. The entire group of nine packaging units 21 is thus significantly more compact than the original situation shown in FIG. 5 .
[0054] The following illustrates the sequence of the method according to the invention and the operation, respectively, of the packaging machine 1 according to the invention.
[0055] As already explained above, packaging units 21 are produced in the thermo-forming packaging machine 1 , in that packaging trays 14 are sealed in the sealing station 3 with a top film 10 . The packaging units 21 are attached to each other in a common film composite 5 , which is located in a horizontal plane E (see FIG. 2 ) and is formed from the lower film 8 and the top film 10 .
[0056] In a main processing cycle of the packaging machine 1 , a group of n (for example 3×3) simultaneously produced packaging units 21 are conveyed into the complete cutting station 4 . There, the conveying system 27 lowers its conveyor elements 28 , until the head portions 29 of the conveyor elements 28 each engage with a packaging unit 21 . By applying a negative pressure to the head portions 29 , the packaging units 21 are fixed to the conveyor elements 28 so that the packaging units 21 , also when being cut out from the film composite 5 , initially maintain their positions relative to each other.
[0057] In the next step, the complete cutting tool 24 is lowered, so that the cutting edges 25 of the cutting knife 30 severe the film composite 5 and thus separate the packaging units 21 form each other in a single processing step. Subsequently, the conveyor elements 28 move in the vertical direction from their retracted to a downwardly extended position, see FIG. 3 or 4 . The top side of the packaging units 21 is thus located below the plane E of the original film composite 5 and preferably below a lower edge of the complete cutting station 4 .
[0058] Now, the distances between adjacent packaging units are reduced. This can be done either by pivoting at least some conveyor elements 28 (see FIG. 3 ) or by a translational movement 28 of certain conveyor elements 28 in the horizontal direction, see FIG. 4 . For this, each second conveyor element 28 is lowered slightly further than the respective adjacent conveyor element 28 so that the edges 31 of adjacent packaging units 21 can push onto each other and an overlap between adjacent packaging units 21 arises (see FIGS. 3 , 4 and 6 ).
[0059] The mutually overlapping packaging units 21 can now, if necessary, be further lowered and be placed in a common outer packaging unit 22 which is located below the complete cutting station 4 . Once the packaging unit 22 is sufficiently filled, meaning contains a desired number of packaging units 21 , it can be removed by the conveyor element 23 . It is possible that the outer packaging unit 22 can contain only one or several layers of packaging units 21 one above the other.
[0060] Based on the embodiment illustrated, the complete cutting station 4 according to the invention and the method according to the invention can be modified in many ways. It is in particular conceivable that any number of packaging units in n tracks and/or m rows is produced simultaneously. The complete cutting tool 24 and the conveying system 27 should then be configured in order to be able to simultaneously separate the respective group of packaging units and convey it out of the complete cutting station 4 . | The invention relates to a complete cutting station for separatingly cutting out packaging units from a film composite by means of a movable complete cutting tool configured for severing the film composite. The complete cutting station further comprises a conveying system having a plurality of conveyor elements for conveying a respective separated packaging unit, wherein each conveyor element in turn comprises a head portion for engaging with a respective packaging unit. The invention is characterized in that the head portions of the conveyor elements are movable between a first position in which packaging units that they gripped are at a first distance to each other defined by the film composite, and a second position in which the packaging units are at a second, smaller distance from each other or at least partially overlap in at least one spatial direction. |
[0001] This application claims the benefit of Italian Patent Application No. MI2011A002081 filed Nov. 16, 2011, which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to an emergency door locking device for household appliances, in particular for tumble dryers.
[0003] More specifically, the device according to the present invention relates to a device suitable for locking the door of the household appliance, thus preventing the opening thereof by the user, when a predetermined temperature is reached inside the household appliance compartment.
BACKGROUND OF THE INVENTION
[0004] Door locking devices suitable for preventing the accidental or voluntary opening of the door of the household appliance by the user under certain conditions are currently available on the market and commonly used in the sector of household appliances such as washing machines, tumble dryers, ovens and so forth.
[0005] For example, the use of said door locking devices in household ovens is known in the prior art, in particular in self-cleaning ovens with pyrolysis function, but also in washing machines, in which the door locking device is controlled by the control electronics of the household appliance and keeps the door tightly closed during the entire operating cycle of the household appliance.
[0006] In certain types of household appliances however, a further safety function may be required that is not linked to the normal operating cycle of the household appliance itself but is linked to the occurrence of specific emergency situations.
[0007] One example of such a situation may be the case in which a fire starts, or in any case, a higher than normal temperature is recorded inside the drum of a washing machine. In this situation, which could also compromise the correct operation of the control electronics of the household appliance itself, there is currently a need which is not met, for an additional mechanical safety device to prevent the door from being opened.
[0008] Indeed, as is known by those with planning experience, purely mechanical safety devices capable of guaranteeing operation, even when the device's control electronics have been compromised, are generally envisaged alongside electronic devices.
SUMMARY OF THE INVENTION
[0009] The main aim of the present invention is therefore that of providing an emergency door locking device, suitable for firmly locking the opening of the door only on the occurrence of certain, predetermined conditions, which constitutes a mechanical safety lock, thus allowing a need identified in the sector to be met.
[0010] In particular, the aim of the present invention is that of providing a thermostatic emergency door locking device that is suitable for entering into operation only on the reaching of a predetermined temperature. Even more in particular, said device, once placed in the compartment of the household appliance at the level of the door's hook closure, detects the temperature present inside the internal compartment of the household appliance and releases, thus locking the door once said temperature reaches a threshold value.
[0011] Within the scope of these aims, the object of the present invention is to provide a mechanically activated, emergency door locking device suitable for being released thus locking the door within a predetermined time interval from when the temperature inside the household appliance has reached a predetermined threshold value.
[0012] Yet another object of the present invention is that of providing a door locking device suitable for use with doors having hook closures of different dimensions.
[0013] Not last, object of the present invention is that of providing a door locking device capable of eliminating the dimensional tolerances that are to be found on the hook closures of the doors of domestic appliances.
[0014] This aim and these and other objects that will become clearer below following a detailed description of the present invention given here by way of a non-limiting example, are achieved by a safety door locking device comprising a main body to which sliding locking means of the door hook of the household appliance are associated, said locking means being mobile between a first inactive position in which said means do not interact with said door hood and a second, locking position of the door in which said means interact with said door hook, said locking means being associated to an elastic element adapted to move said locking means from said first position that is retracted towards the external of said main body in said second locking position, characterised in that the said locking means comprise, at the end intended to come into contact with said hook of said door, a serrated profile, said profile further presenting at least one abutment adapted to be held by a portion of a thermostatic element, so as to keep said locking means in a retracted position when the temperature detected by said thermostatic element is lower that a predetermined value T 1 .
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Further characteristics and advantages of the present invention shall become clearer from the following detailed description, provided by way of a non-limiting example and is illustrated in the annexed drawings, wherein:
[0016] FIG. 1 shows a perspective top view of the door locking device according to the present invention in accordance with a first embodiment thereof;
[0017] FIG. 2 again shows a perspective top view of the device of FIG. 1 in a condition wherein the locking means do not interact with the door hook;
[0018] FIG. 3 shows a sectional side view of the door locking device in accordance with the embodiment of drawings 1 and 2 , in a condition in which the said locking means interact with the door hook;
[0019] FIG. 4 shows a detail of the thermostatic element according to the first embodiment of the device of the present invention;
[0020] FIG. 5 shows a perspective top view of the door locking device according to the present invention in accordance with a second embodiment thereof;
[0021] FIG. 6 again shows a perspective top view of the device of FIG. 5 in a condition in which the locking means do not interact with the door hook;
[0022] FIG. 7 shows a sectional side view of the door locking device in accordance with the embodiment of drawings 5 and 6 , in a condition in which the said locking means interact with the door hook;
[0023] FIG. 8 shows a detail of the thermostatic element according to the second embodiment of the device of the present invention;
[0024] FIG. 9 shows the device according to the present invention, coupled with the door hook of a household appliance. The figure shows how the device is able to eliminate any misalignment of the hook and the device.
DETAILED DESCRIPTION OF THE INVENTION
[0025] With particular reference to FIG. 1 , the device 1 according to the present invention comprises a main body 10 preferably having a box shape.
[0026] The main body 10 can be advantageously made of a single, suitably bent sheet element, or can be obtained the unison of multiple sheet metal parts, but could also be obtained from other materials having physical and mechanical properties suitable for the purpose.
[0027] The main body 10 is intended to be firmly connected to the household appliance or to a part thereof 200 inside the compartment of the household appliance itself and in proximity of the door, in particular of the door's hook closure 100 .
[0028] The device according to the present invention comprises locking means 20 of said door that are movable between a first position in which said means do not interact with said door hook 100 and a second locking position of the door in which said means interact with said door hook 100 .
[0029] Said locking means comprise, in the example shown in the accompanying drawings, a rod 20 having a substantially longitudinal development, which presents at least one portion 21 shaped like a blade adapted to interact with said hook 100 of said door of the household appliance when said locking means are in the second locking position.
[0030] In particular, at the level of said first position in which said means do not interact with said hook 100 , said rod 20 is refracted within the main body 10 of the device, while at the level of the second door locking position, said road protrudes from the main body 10 of the device towards the outside from the part of said main body which, when the device is assembled onto the household appliance as shown in FIG. 1 , faces towards said hook 100 , the end portion 21 of said road going on to interact with said hook 100 thus maintaining the door in a closed position.
[0031] According to the preferred embodiment shown in the accompanying drawings, the rod 20 has a substantially longitudinal development, and is shaped like a foil, the thickness of which is contained.
[0032] Other forms may naturally be envisaged by persons skilled in the art according to their specific experience and without deviating from the scope of protection of the present invention defined by the accompanying claims.
[0033] As mentioned, the rod 20 presents one end 21 adapted to interact with the hook 100 of said door. In particular, the end 21 of said rod presents, on a longitudinal plane, an inclined profile, that is for example triangular or wedge-shaped.
[0034] With particular reference to the view of FIG. 3 , which shows a section of the present device with an axial longitudinal plane, it is noted how the rod 20 presents at the level of the end 21 a tapered section in the advancement direction of the rod 20 from the first inactive position to the second door locking position. Said tapered section further presents a serrated profile 23 .
[0035] Defining the terms “above”, “below”, “lower” and “upper”, in compliance with the identified direction of the axis Z of the reference system shown in FIGS. 1 and 3 , and the terms “front” and “rear”, “advancement” e “backward motion” with reference to the identified direction of the axis X, said end 21 of the rod 20 is wedge-tapered and presents, at least at the level of its upper edge, a serrated profile comprising a plurality of serrations 23 , each of said serrations being suitable to abut the internal profile of said hook 100 , which is normally ring-shaped.
[0036] Thanks to the particular wedge-shape of the end 21 of the rod 20 , and thanks in particular to the serrated profile comprising a plurality of 23 at least on the upper edge of said end 21 , the rod 20 is able to insert itself inside the ring of the hook 100 , thus eliminating any slack or tolerances that may exist between the positioning of the hook 100 and that of the device 1 . Said advantage obtainable by the device according to the present invention is well illustrated by FIG. 9 , in which it is noted how the plurality of serrations 23 of the serrated profile and the wedge-shape of the end 21 of the rod 20 are able to eliminated misalignments of the door hook 100 in respect of both the axis X and the axis Z.
[0037] Indeed, in particular, it is intuitive how the end 21 of the rod 20 will always be able to find the desired interference with the internal profile of the hook 100 , even when the positioning of the ring of the hook along the axis Z should not be perfectly aligned in respect of the rod 20 .
[0038] The function carried out by the presence of the serrated profile of the end 21 will become clearer once the methods by which the rod 20 moves along the direction X have been illustrated.
[0039] The movement of said rod 20 along the longitudinal direction X takes place thank to the presence of actuating means 30 .
[0040] In particular, in the example shown in the drawings, said actuating means 30 comprise elastic means, in particular a helical spring 30 , interposed between said main body 10 and said rod 20 .
[0041] In particular, said helical spring 30 is compressed when said rod 20 is in said first position, refracted inside said main body 10 , in which it does not interfere with said hook 100 of said door. In this condition therefore the action of the spring exercises a force on said rod 20 , onto which the spring itself abuts, which tends to push the rod 20 into said second locking position of the door hook, in which the end 21 of said rod 20 protrudes from the main body 10 .
[0042] The device according to the present invention thus further comprises at least one thermostatic element 40 comprising at least one abutment adapted to interact with said locking means 20 thus contracting the thrust exercised on said locking means 20 by the spring 30 when said locking means are in the first position of non interference with said hook 100 of said door.
[0043] In the examples shown in the accompanying drawings said thermostatic element 40 is made of a bimetal.
[0044] As is known in the prior art, the term “bimetal” here indicates a sheet consisting of two thin metal bands, each having different chemical and physical properties, that are joined together by means of any procedure whatsoever, for example by means of lamination or compression.
[0045] In the present patent description, the term “bimetal” indicates a thermal bimetal or bimetallic foil, with which the springs, discs, foils for sensitive elements of thermostats, switches and similar are made, according to what is known in prior art. It is thus formed by two metals having very different linear expansion coefficients from each other (for example iron and brass, nickel and iron, platinum and iridium). The bimetal flexes by effect of the temperature variation.
[0046] Bimetal deformation can be controlled by suitably selecting the materials, the thicknesses and so forth, so as to “programme” the bimetal to deform at a given temperature T 1 .
[0047] According to the first embodiment of the device according to the present invention, shown in FIGS. 1 to 4 , the thermostatic element 40 is made of a bimetal with non-linear deformation, preferably of the “on-off” type also indicated in the sector by the English term “snap”, adapted to firmly maintain said locking means 20 in their first position when the temperature detected by said thermostatic device is inferior to a predetermined value T 1 . Since, as mentioned, the device according to the present invention is advantageously positioned inside the compartment of the household appliance, it detects the temperature T present inside the compartment.
[0048] When the temperature T inside the compartment exceeds the predetermined threshold value T 1 , the bimetal 40 instantly deforms, the portion 41 of said bimetal 40 no longer abuts the portion 24 of said locking means 20 , and the rod 20 is therefore free to move forward towards the locking position of the door pushed by the spring 30 .
[0049] According to the first preferred embodiment of the present invention shown in FIGS. 1 to 4 , the thermostatic element 40 is made of a bimetal with non-linear deformation.
[0050] When the device 1 according to the present invention is equipped, as in the second embodiment of FIGS. 5 to 8 , with a bimetal with linear deformation, when the temperature detected by the device reaches the value T 1 the linear deformation of the bimetal element 40 ′ begins to deform and the safety device 1 does not therefore immediately snap into closing the door, but there will be a transitional period from the moment in which the device detects the temperature T 1 and the moment in which the serration 41 ′ frees the rod 20 , triggering the device.
[0051] By suitably dimensioning the thicknesses of the bimetal and suitably selecting the type of materials that comprise it, it is possible to determine the duration of the deformation transition of the bimetal 40 ′.
[0052] It has thus been shown that the method and the apparatus according to the present invention achieve the proposed aim and objectives.
[0053] In particular, it has been illustrated how the door locking device according to the present invention allows a single, extremely simple mechanical safety device to be used that is suitable for producing the locking of the door of a household appliance on a predetermined temperature being reached.
[0054] It has also been shown how the emergency door locking device according to the present invention allows any alignment problems between the locking device itself and the door hook, thus simplifying the assembly operations of the device, particularly as regards the dimensional control of the positioning.
[0055] A number of changes can be made by the sector profession without straying from the scope of protection pursuant to this invention.
[0056] The scope of protection of the claims should not therefore be restricted to the illustrations or to the preferred embodiments provided by way of example in the description; the claims should instead include all the characteristics of patentable novelty arsing from the present invention, including all the characteristics that are deemed to be equivalent by a person skilled in the art. | The present invention relates to an emergency door locking device for household appliances, in particular for tumble dryers, More specifically, the device according to the present invention allows the door of a household appliance to be locked, thus preventing the opening thereof by the user, when a predetermined temperature, deemed anomalous and/or dangerous, is reached inside the compartment of the household appliance. The emergency device according to the present invention therefore constitutes a mechanical safety, which is therefore also able to operate when the anomalous event that caused the increase in temperature compromises the correct operation of the control electronics of the household appliance. |
This is a Continuation-In-Part of application, Ser. No. 612,118 filed on Sept. 10, 1975 and now U.S. Pat. No. 3,978,927.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the recovery of oil from subterranean formations by chemical flooding methods.
2. Description of the Prior Art
Petroleum is frequently recovered from subterranean formations or reservoirs by permitting the natural energy of the reservoir to push the petroleum up through wells to the surface of the earth. These processes are referred to as primary recovery methods since they use the natural energy of the reservoir. However, a large amount of oil, generally in the range of 65-90% or more, is left in the subterranean formation at the conclusion of the primary recovery program. When the natural reservoir energy is unable to produce more petroleum, it is a common practice to resort to some form of supplemental recovery technique in order to recover additional petroleum left in the subterranean formation. These supplemental operations are normally referred to as secondary recovery operations. If this supplemental recovery operation is the second in a series of such operations, it will be referred to as a tertiary recovery operation. However, the terminology is unimportant for the purposes of this application and relates only to the sequence in which the are carried out.
The most widely used supplemental recovery technique because of its ease of implementation and low capital outlay is water flooding through injection wells drilled into the subterranean formation. In a water flooding operation, the injected fluid displaces oil through the formation to be produced from the production well. A major disadvantage to water flooding, however, is its relatively poor displacement efficiency largely due to the fact that water and oil are immiscible at reservoir conditions and high interfacial tension exists between the flood water and the oil. For this reason, after a water flood, a large portion of the oil is still left unrecovered in the reservoir.
It has been recognized by those skilled in the art that a solution affecting a reduction in this interfacial tension between water and oil would provide a much more efficient recovery mechanism. Therefore, the inclusion of a surface active agent or surfactant in the flood water was recognized as an acceptable technique for promoting displacement efficiency of the reservoir oil by the water. For example, U.S. Pat. No. 3,468,377 discloses the use of petroleum sulfonates in water flooding operations and U.S. Pat. No. 3,553,130 discloses the use of ethylene oxide adducts of alkyl phenols for the same purpose. The use in water flooding operations of water soluble surface active alkaline earth resistant polyglycol ethers is disclosed in U.S. Pat. No. 2,333,381. Other specialized surfactants, as will be discussed later, have been discovered to have special properties useful in water flooding operations such as a tolerance for high salinity and calcium, magnesium and/or ion concentrations often found in reservoir waters.
However, field operations employing surfactants and surface active agents in injecting fluid have not always been entirely satisfactory due to the fact that these materials are often adsorbed by the formation rock to a relatively high degree, resulting in an ever declining concentration of the materials as they progress through the reservoir. Therefore, large concentrations of surface active materials have heretofore been necessary to maintain a sufficient concentration at the oil-water interface. Due to this, many proposed flooding operations involving surface active materials have been uneconomical.
Another serious problem for any recovery techniques involving the driving of oil with a fluid is premature breakthrough of the injection fluid. This premature breakthrough indicates that the reservoir has not been adequately swept of oil. The problem is often described in terms of sweep efficiency as distinguished from the displacement efficiency described above. Displacement efficiency involves a microscopic pore by pore efficiency by which water displaces oil, whereas sweep efficiency is related to the portion of the reservoir which is swept and unswept by the injected fluid. A major cause of poor sweep efficiency is associated with the fact that the injected fluid generally has a lower viscosity than the displaced fluid or petroleum. Thus, the injected fluid has a higher mobility and tends to finger through the oil thus prematurely breaking through to the production well.
The solution to this high mobility problem is to increase the viscosity of the driving fluid. One way to do this is to add polymeric organic materials to a driving water which has the effect of increasing the viscosity of the water, thereby increasing the sweep efficiency of the supplemental recovery process. U.S. Pat. No. 3,039,529 and U.S. Pat. No. 3,282,337 teach the use of aqueous polyacrylamide solutions to increase the viscosity of the injected fluid thereby promoting increased sweep efficiency. Polysaccharides as taught in U.S. Pat. No. 3,581,824 have been used for the same purpose. These polymers are quite expensive and any polymer lost to adsorption on the reservoir matrix adds substantially to the cost since additional polymer is required to maintain a given viscosity.
The above described problems have been recognized by those skilled in the art of oil recovery and certain sacrificial compounds have been added to pretreat the formation in order to decrease the adsorption of subsequently injected surfactants and/or polymers. For example, U.S. Pat. No. 3,414,054 discloses the use of aqueous solutions of pyridine; U.S. Pat. No. 3,469,630 discloses the use of sodium carbonate and inorganic polyphosphates, and U.S. Pat. No. 3,437,141 discloses the use of soluble carbonates, inorganic polyphosphates and sodium borate in combination with a saline solution of a surfactant having both a high and a low molecular weight component. These materials have not been completely satisfactory from a standpoint of performance and economics, however.
SUMMARY OF THE INVENTION
The invention is a process of producing a petroleum from subterranean formations having an injection well and a production well in communication therewith. The process comprises injecting into the formation via the injection well an aqueous solution of alkoxylated asphalts and then injecting via the injection well into the formation a chemical oil recovery agent, for example, surfactant and/or polymer, thereby displacing oil from the subterranean formation to the surface of the earth.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A sacrificial material is injected by the process of this invention through an injection means comprising one or more injection wells into a subterranean petroleum-containing formation to preferably occupy or cover all potential adsorption sites of the rock within the subterranean formation thereby reducing the extent of adsorption of the more expensive chemical oil recovery agent injected therebehind. A sacrificial agent performs best when it exhibits high adsorption on active sites of rock surfaces, and thus diminishes surfactant and/or polymer adsorption. Chemical compounds of polyelectrolytic nature have the proper physico chemical and structural requirements to behave as successful sacrificial agents. The functional group on the sacrificial agent molecules enhances adsorption either by hydrogen bonding or electrostatic attraction to active sites on the rock surfaces.
A satisfactory sacrificial material has at least three important characteristics. First, it should be less expensive than the surfactant since it cannot be recovered. Next, it must be adsorbed readily by the subterranean formation matrix. Preferably the sacrificial material should be adsorbed more readily than the chemical oil recovery agent to be used in the process. This will enable the sacrificial agent to be used not only as a preflush but in admixture with the chemical recovery material. The third important characteristic of a sacrificial agent is that the presence of such adsorbed sacrificial material must retard or eliminate the subsequent adsorption of the surfactant and/or polymer chemical recovery material on the adsorption sites of the formation rock. By adsorption sites of the formation rock is meant those parts of the surfaces of the pores of the formation rock capable of adsorbing a chemical compound from a solution on contact.
The sacrificial material does not always have an appreciable effect on the recovery efficiency of the chemical flooding operation. Additional oil is generally recovered only if the sacrificial material is followed by or is admixed with a surfactant and/or a polymer chemical recovery agent which will effectively increase the amount of oil displaced from the subterranean formation. This is not always true as in this invention where the sacrificial agent has surface active properties. When a surfactant is chosen as the chemical recovery agent it should be injected after the sacrificial agent or in admixture therewith and ahead of the following flooding water thereby achieving the desired interfacial tension reduction between the injected fluid and the displaced fluid without loss of surfactant on the formation matrix. The surfactant may be present in a hydrocarbon solvent or in an aqueous solution or in a combination thereof. Any type of surfactant known in the art may be used in the practice of this invention. Some types of surfactants were mentioned previously. In addition, surfactants disclosed and claimed in the following U.S. patents are particularly useful since they have been found to be capable of performing in reservoirs having both high salinities and high hardness levels: U.S. Pat. Nos. 3,858,656; 3,811,505; 3,811,504; 3,811,507.
Likewise, the amount of surfactant which must be employed in the practice of any chemical flood is generally known in the art and is to be found in published literature. However, the concentration of surfactant generally will range from 0.01 to 0.1 pore volumes of an aqueous surfactant solution having dissolved therein from 0.001 to 0.5 percent by weight of the surfactant itself. As mentioned before, in addition to a preflush or a substitution thereof, a small amount of the sacrificial material may also be added to the surfactant solution to prevent the adsorption of the surfactant on the formation matrix.
In carrying out this invention, a sacrificial material comprising alkoxylated asphalts is injected via the suitable injection means, i.e. through one or more injection wells completed in the subterranean hydrocarbon formation, so that the sacrificial material enters the formation ahead of the surfactant. The surfactant is then injected into the subterranean hydrocarbon-containing formation followed by the injection water to drive it to the production well. By injecting the sacrificial material in this particular sequence, the sacrificial material adsorbs on and occupies the sites existing in the matrix of the formation thereby eliminating or substantially decreasing the tendency for the subsequently injected surfactant and/or polymer to adsorb on the rock matrix.
The sacrificial agents useful in the process of my invention are alkoxylated asphalts.
Many types of asphalts are useful in the process of this invention. The American Society for Testing and Materials defines asphalts are "A dark brown to black cementitious material, solid or semi-solid in consistency, in which the predominating constituents are bitumens which occur in nature as such or are obtained as residua in refining petroleum." Thus, asphalts occur naturally or may be obtained as residues in petroleum refining. The Kirk-Othmer Encyclopedia of Chemical Technology, Volume 2 at pages 762 to 789 discusses the general characteristics of various types of asphalts.
Petroleum derived asphalts may be further divided into straight reduced asphalts which are obtained in reduced pressure stills or precipitated with propane or butane. Also, asphalts may be obtained from the residues of cracking operations. Petroleum derived asphalts may also be of air blow variety.
Naturally occurring asphalts include gilsonite graphamite, glance pitch, Burmudez, rock asphalts and Trinidad.
Many other examples of both petroleum derived and natural asphalts could be given but the above description will apprise those skilled in the art of asphalts stocks acceptable for use in this invention.
Since the asphalt is to be alkoxylated, it must contain active hydrogens. Determination of the active hydrogen content of any particular stock is easily determined by known analytical techniques.
The preferred alkylene oxide for reacting with the asphalts in our invention are ethylene oxide and propylene oxide or mixtures thereof so that the resulting alkoxylated asphalt is water soluble. Most preferably, ethylene oxide or a major amount of ethylene oxide and a minor amount of propylene oxide should be used. The ratio of alkylene oxide to asphalt should be such that the resulting product is water soluble. A suggested range of ethoxylation is from about 20 to about 800 moles of ethylene oxide per mole of asphalt. This range is given only as a guide. One skilled in the art will recognize that the proper amount of alkoxylation will depend on many variables including the type of asphalt, the type of formation, water salinity and the type of surfactant in the flood.
The quantity of sacrificial ethoxylated asphalts to be injected into the subterranean hydrocarbon formation may be any amount up to and including an amount sufficient to occupy substantially all of the active sites of the formation matrix. If less than the maximum amount is used, there will be a corresponding reduction in the adsorption of surfactant from injection solution onto the formation matrix although the amount of reduction will not be as great as in the case where the formation is completely saturated with sacrificial ethoxylated asphalts. At a maximum only the amount of ethoxylated asphalts needed to completely occupy the active sites on the formation is needed. The only detriment resulting from using excess sacrificial material would be an increase in the cost of operating the oil recovery program.
The amount of sacrificial ethoxylated asphalts needed in the process of the invention depends on the particular formation, the area or pattern to be swept and other formation characteristics. It is convenient to express the quantity of sacrificial agents needed in terms of pounds of material per acre foot of formation for the particular pattern which the injection fluid is expected to sweep. Ordinarily from about 15 to about 150 pounds per acre foot of formation of the sacrificial ethoxylated asphalts described in the specification would be sufficient to prevent substantial adsorption of surfactant from injected surfactant solution.
Optionally, a trailing fluid such as an aqueous fluid may be used to follow the surfactant so that a smaller amount of surfactant may be used.
The effectiveness of this invention for reducing the adsorption of surfactant or polymer on formation rock and chemical flooding operations is demonstrated by the following examples which are presented by way of illustration and are not intended as limiting the spirit and scope of the invention as defined in the claims.
PREPARATION OF AN ETHOXYLATED ASPHALT
The following procedure described the ethoxylation of an asphalt. The asphalt was originally obtained by deasphalting during the manufacture or lubricating oil in a vacuum reducing still. The asphalt has a melting point of 215°-300° F. and was air blown at 500° F. resulting in a hydroxyl number of 30. A 2 liter Parr reactor was charged with 50 gms (0.02 moles) of crushed asphalt, 1.4 gms potassium hydroxide flakes, and 500 ml of toluene. The reactor was sealed and purged several times with nitrogen. A cylinder containing the prescribed quantity of ethylene oxide was attached to the reactor in such a way as to allow the ethylene oxide to be discharged at the bottom of the reactor. The reactor temperature was then raised to approximately 160° C. Upon reaching 160° C. the ethylene oxide was added in several additions. After all the ethylene oxide had been added (15 moles) the reaction mixture was kept at 160° C, for 1 hour. The Parr reactor was then cooled and purged with nitrogen. The toluene was evaporated leaving the ethoxylated asphalt product. This product was used in the data shown in Tables I and II.
EXPERIMENTAL
Adsorption and capillary displacement tests were performed on the mixtures in Table I below.
The adsorption test was performed to determine the tendency for dodecyl benzene sulfonate surfactant to adsorb on a calcium carbonate substrate. The test was performed by placing a weighed amount of calcium carbonate powder into containers along with various surfactant solutions as shown in Table I. The containers were then agitated uniformly and the amount of adsorption of dodecyl benzene sulfonate was measured as follows.
An aliquot of the mixtures was titrated against a 5× 10 31 4 molar solution of CH 3 (CH 2 ) 15 N(CH 3 ) 3 Cl to determine the dodecyl benzene sulfonate concentrations in the test samples. Table II shows the dodecyl benzene sulfonate concentrations in these mixtures after the tests along with capillary displacement data.
Capillary displacement tests are a convenient and accurate method for measuring the ability of an aqueous solution of surfactant to displace a fluid such as crude oil.
The tests are performed by filling a number of closed and capillary tubes with the particular crude oil being studied, and submerging the capillary tubes horizontally into the desired aqueous phase.
In each instance of displacement of oil by the aqueous phase, a meniscus is formed at the oil-water interface. The only force tending to displace oil from the capillary tube was the force resulting from the difference in specific gravities of the two fluids. This force was offset by the interfacial tension between the oil and formation water.
When the surfactant composition was successful in producing a movement in the meniscus, the distance traveled by the meniscus in millimeters in a 5 minute exposure interval in the chemical system is recorded.
Adsorption and capillary displacement tests were performed on the mixtures in Table II.
TABLE I______________________________________ 9.5 Mole Dodecyl Ethylene Ethoxy- Benzene Oxide Adduct latedTest # Sulfonate of Nonyl Phenol Asphalt Substrate______________________________________I 1) 0.4% 0.6% 0 None 2) 0 0 0.2% None 3) 0.4% 0.6% 0 20g CaCO.sub.3 4) 0.4% 0.6% 0.2% None 5) 0.4% 0.6% 0.2% 20g CaCO.sub.3 6) 0.4% 0.6% 0.2% 20g CaCO.sub.3II 1) 0.4% 0.6% 0.5% None 2) 0.4% 0.6% 0.5% 20g CaCO.sub.3 3) 0.4% 0.6% 0.5% 20g CaCO.sub.3 *III 1) 0.4% 0.6% 1.0% None 2) 0.4% 0.6% 1.0% 20g CaCO.sub.3 3) 0.4% 0.6% 1.0% 20g CaCO.sub.3______________________________________ *Indicates pretreatment of CaCO.sub.3 with the asphalt solution and subsequent addition of dodecyl benzene sulfonate and the 9.5 mole ethylen oxide adduct of nonyl phenol. All the tests were performed at constant salinity and 190° F.
TABLE II______________________________________ Sulfonate CapillarySulfonate Sulfonate Loss DisplacementTest # Content Loss g of CaCO.sub.3 300 sec. 600 sec.______________________________________I 1) 0.2125g 7.9 mm 12 mm 2) 0.00g 0 0 3) 0.1254g 0.0871g 0.0044g 0 0.2 mm 4) 0.2125g 7 mm 9 mm 5) 0.2019g 0.0106g 0.0005g 6.6 mm 9.6 mm 6) 0.1976g 0.0149g 0.0007g 7.2 mm 10.2 mmII 1) 0.2125g 8.1 mm 10.5 mm 2) 0.2008g 0.0117g 0.0006g 6 mm 7.5 mm 3) 0.1998g 0.0127g 0.0006g 9 mm 13.2 mmIII 1) 0.2125g 7.5 mm 9 mm 2) 0.1966g 0.0159g 0.0008g 8.3 mm 11.2 mm 3) 0.1976g 0.0149g 0.0007g 8.5 mm 11.8 mm______________________________________ Conclusions: 1) Adsorption loss in dodecyl benzene sulfonate concentration in the abov experiment in absence of ethoxylated asphalt was approximately 41% of initial concentration or 4.4 mg. 2) After addition of concentration ranging from 0.2% - 1.0% ethoxylated asphalt, the adsorption loss was reduced to 5 - 8% or 0.5 to 0.8 mg/g. 3) Capillary displacement tests indicated no interference from the ethoxylated asphalt in the activity of the surfactant system. | A process for producing petroleum from subterranean formations is disclosed wherein production from the formation is obtained by driving a fluid from an injection well to a production well. The process involves injecting into the formation via the injection well an aqueous solution of alkoxylated asphalts as a sacrificial agent to inhibit the deposition of surfactant and/or polymer on the reservoir matrix. Normally the process would be carried out by first injecting the alkoxylated asphalts into the formation through the injection well and following them with either a polymer or a surfactant solution. |
FIELD OF THE INVENTION
This invention relates to decoders such as are used to drive the pixels of a display, and more particularly to testing of decoders.
BACKGROUND OF THE INVENTION
Decoders are widely used in displays, such as Liquid Crystal Displays (LCDs). As is well known to those having skill in the art, in an LCD, a source driver for a thin film transistor (TFT) drives the thin film transistor with an output voltage that corresponds to data for displaying the brightness of the red (R), green (G) and blue (B) portions of a given pixel. In one example, 300 decoders may be present, each of which is responsive to one of 64 contrast levels, to produce a respective output level corresponding to the selected contrast level. The 64 contrast levels may be provided using six bits of multibit input data, to provide a selected voltage V 1 -V 64 corresponding to 64 output levels.
In view of the large numbers of decoders and the large numbers of output levels that each decoder can provide, testing of the decoders may be extremely time consuming. More specifically, in conventional test programs, the output of each decoder is cycled through each of the output levels. Thus, if 300 decoders are present, each of which provides an output voltage level V 1 -V 64 in response to six bits of input data, 65 cycles may be needed to test all of the output voltage levels. Each cycle may use at least 100 shift clocks and one latch clock. Accordingly, the time for testing the decoders can be unacceptably long.
FIGS. 1 ( a )- 1 ( f ) are conventional timing diagrams for conventional decoder testing. Input data for a plurality of channels is serially latched into a data register in response to a shift clock (SCLK) shown in FIG. 1 ( a ). All the data latched to the data register is simultaneously output in response to a latch clock (LCLK) shown in FIG. 1 ( b ). A conventional test for decoders may use 100 shift clocks since input data with respect to R, G and B are input at one time in response to one clock of the shift clock (SCLK).
FIG. 1 ( c ) shows input data which has the same value. Real input data is separate data; however, data having the same value are used for a test. FIGS. 1 ( d ) through 1 ( f ) show the outputs of output channels OUT 1 through OUT 300 , which are output at one time in response to the latch clock (LCLK). As shown, times of 64 contrast levels×100 shift clocks may be needed if such outputs are performed with respect to 64 contrast levels.
As a result, a testing time of at least the number of contrast levels times the period of shift clock times the number of outputs may be needed for testing the decoders. Since more than five types of tests may be performed in order to test a decoder in an integrated circuit, most of the test time for the integrated circuit may be consumed on testing the decoders.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide improved decoders and decoder testing methods.
It is another object of the present invention to provide decoders and decoder testing methods that can reduce the amount of time that is used to test the decoders.
These and other objects are provided according to the present invention, by simultaneously applying the same multibit input data to a plurality of decoders in response to a test mode signal. It has been found, according to the invention, that since all of the decoders are being tested, the same data may be input to all of the decoders without inputting separate data through the decoder input terminals, as is the case during normal decoding operations. Accordingly, the time for testing the decoders can be reduced.
More specifically, according to the invention, a decoding system includes a plurality of decoders, a respective one of which is responsive to respective multibit input data, to decode the respective multibit input data and produce a respective output level corresponding to the respective multibit input data. Means and methods are provided for simultaneously applying the same multibit input data to the plurality of decoders, in response to a test mode signal. Different multibit input data is then simultaneously applied to the plurality of decoders, so that all of the output levels of the decoders can be tested. The output levels from the plurality of decoders that result from the same multibit input data that is supplied to the plurality of decoders is detected. The detected output levels from the plurality of decoders that result from the same multibit input data that is applied to the plurality of decoders is compared to expected output levels in order to test the decoders. The multibit input data preferably is N-bit input data, so that one of 2 N combinations of the N-bits is simultaneously applied to the plurality of decoders in response to the test mode signal.
In a preferred embodiment, the plurality of decoders comprises a plurality of red, green and blue signal decoders for a color display. The same first multibit input data is simultaneously applied to the plurality of red decoders, the same second multibit input data is simultaneously applied to the plurality of green decoders, and the same third multibit input data is simultaneously applied to the plurality of blue decoders, in response to the test mode signal.
The same multibit input data is preferably simultaneously applied to the plurality of decoders by providing a plurality of data registers that latch the same multibit input data therein and that simultaneously apply the latched multibit input data to the plurality of decoders. A controller produces a shift clock and a latch clock in response to the test mode signal. A shift register is responsive to the shift clock to generate a plurality of input control clocks. The plurality of data registers are responsive to the plurality of input control clocks, to latch the same multibit input data therein. The data registers are responsive to the latch clock, to simultaneously apply the latched multibit input data to the plurality of decoders.
Accordingly, improved decoders and testing apparatus and methods for decoders are provided that can reduce the testing time for the decoders.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 ( a ) through 1 ( f ) are conventional timing diagrams for testing decoders;
FIG. 2 is a schematic block diagram of an output portion in an embodiment of a Liquid Crystal Display (LCD) source driver according to the present invention;
FIG. 3 is a block diagram showing a preferred embodiment of decoder test controlling apparatus and methods according to the present invention;
FIGS. 4 ( a ) through 4 ( i ) are timing diagrams for testing a decoder shown in FIG. 3;
FIG. 5 is a block diagram showing another preferred embodiment of decoder test controlling apparatus and methods according to the present invention;
FIGS. 6 ( a ) through 6 ( i ) are timing diagrams for testing a decoder shown in FIG. 5; and
FIG. 7 is a flow chart showing decoder testing methods according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred 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 set forth 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. Like numbers refer to like elements throughout.
FIG. 2 is a schematic block diagram of an output portion of a Liquid Crystal Display (LCD) source driver according to the present invention. Decoders select contrast levels of the output portion of the 64 contrast levels, and 300 channel drivers select a voltage of a level corresponding to input data among voltages V 1 through V 64 corresponding to all the bit combinations of six bit input data.
Each of input data D 1 through D 300 is separate data corresponding respectively to 300 channels OUT 1 through OUT 300 . Three channels are used for R, G, and B display voltages of a pixel. In order to simultaneously output voltage for display on all the pixels in a TFT panel, input data with respect to the respective channels are serially latched to a data register in response to a shift clock before it is input to the respective decoders.
The data register input data with respect to three channels is shifted in response to a shift clock in order to display the degrees of brightness of R, G, and B for a pixel in an LCD panel. Therefore, at least 100 shift clocks may be needed for storing input data for 300 channels in the data register. All the input data latched to the data register are simultaneously output to the respective decoders in response to a latch clock. The respective decoders select voltages corresponding to the input data, from the voltages V 1 through V 64 of levels corresponding to all the bit combinations of the input data. The display voltages are output to the respective channels OUT 1 through OUT 300 through the respective current buffers.
FIG. 3 is a block diagram showing a preferred embodiment of decoder test controlling apparatus and methods according to the present invention, and also includes a schematic block diagram of FIG. 2 . Referring to FIG. 3, decoder test controlling apparatus and methods according to the present invention include a controlling portion 302 , a shift register 304 , a selecting portion 306 , a data register 308 , and an output portion 300 . The output portion 300 includes a decoding portion 310 and a buffering portion 312 . The decoding portion 310 includes a plurality of decoders as shown in FIG. 2 . The buffering portion 312 includes a plurality of buffers as shown in FIG. 2 .
The decoding portion 310 is applied to 64 contrast levels and 300 channel source drivers having three input data DI 0 ˜DI 2 which are respectively formed of 6 bits and 300 output channels OUT 1 through OUT 300 , in order to select the contrast levels of R, G, and B with respect to 100 respective pixels of a panel. However, it is well known to those of the art that such numbers are variable in different decoding systems and methods.
The controlling portion 302 generates a shift clock (SCLK) in response to a second clock (CLK 2 ) after a start pulse DI 01 is externally input, generates a latch clock (LCLK) in response to a first clock (CLK 1 ) having a pulse when the second clock (CLK 2 ) has 100 pulses, and generates a latch enable signal (LEN) in response to a test control signal (TEST).
The shift register 304 serially outputs the shift clocks (SCLK) that is serially input from the controlling portion 302 one by one via a plurality of output lines. For example, when three input data are simultaneously latched in response to a clock output from the shift register 304 , the shift register 304 serially outputs first through 100th shift clocks through 100 output lines. The selecting portion 306 selectively outputs the shift clock (SCLK) and the latch clock (LCLK) that is input from the controlling portion 302 , in response to the test control signal (TEST).
The data register 308 inputs data DI 0 through DI 2 via input terminals IN 1 through IN 3 and serially latches the data to corresponding memories in response to the corresponding 100th shift clocks which are a plurality of input controlling clocks from the shift register 304 . Here, the data DI 0 through DI 2 is formed of six bits. The data register 308 stores the 100th input data in a corresponding memory in response to the 100th shift clock from the shift register 304 and simultaneously outputs all the serially latched data in response to the latch clock (LCLK) from the selecting portion 306 . When the shift clock (SCLK) is generated 100 times in response to the second clock (CLK 2 ), the latch clock (LCLK) is generated once in response to the first clock (CLK 1 ).
The decoding portion 310 inputs the data simultaneously output from the data register 308 and selects the voltages corresponding to the respective data from among the voltages V 1 through V 64 of 64 contrast levels corresponding to all the bit combinations of the six-bit data. The buffering portion 312 simultaneously stores the voltages selected from the decoding portion 310 and respectively outputs them as LCD displaying voltages through the 300 channels. It will be understood that the decoding portion 310 and the buffering portion 312 include a plurality of decoders and buffers corresponding to the number of the data simultaneously input to the decoding portion 310 or the output channels, as shown by the decoders and buffers of FIG. 2 .
The above-described operation of the data register 308 corresponds to the normal operation of the data register 308 , in response to the latch clock (LCLK) from the selecting portion 306 . Operation of the data register 308 when the decoding portion 310 is tested for a circuit verification in the LCD source driver for the TFT will now be described.
To verify the characteristics of the respective decoders of the decoding portion 310 , the data to be input to the respective decoders should be changed to 64 types so that the voltages V 1 through V 64 of the levels of all the cases can be output from the respective decoders. However, since the respective decoders are being tested, the same data may be input to all the decoders through the input terminals IN 1 through IN 3 , without inputting separate data to the decoders as shown in FIG. 2 .
When the test control signal TEST is applied to the above-mentioned controlling portion 302 and the selecting portion 306 , the data register 308 receives the latch enable signal LEN and the shift clock SCLK respectively from the controlling portion 302 and the selecting portion 306 . The data register 308 latches data input once through the input terminals IN 1 through IN 3 to all the memories in response to the latch enable signal LEN. The data register 308 outputs the latched data to all the decoders of the decoding portion 310 in response to the shift clock SCLK whenever it receives a first, second, . . . , or 100th shift clock from the shift register 304 . Therefore, the data register 308 can output all the bit combinations of the data input through the input terminals IN 1 through IN 3 to all the decoders of the decoding portion 310 while 64 shift clocks SCLK are generated. Consequently, the data register 308 can reduce test time by latching input data simultaneously to all the memories and outputting the data to all the decoders of the decoding portion 310 .
FIGS. 4 ( a ) through 4 ( i ) are timing diagrams for testing the decoding portion shown in FIG. 3 . Assuming that a point of time in which a clock after 100 clocks is first generated from the shift clock SCLK shown in FIG. 4 ( a ) is a test mode, 64 clocks after the first 100 clocks are output from the shift register 304 and the selecting portion 306 . Thus, the output MUXO of the selecting portion 306 shown in FIG. 4 ( b ) is the latch clock LCLK during the first cycle and the shift clock SCLK during the next cycles.
The data DI shown in FIG. 4 ( c ) is serially latched in response to first 100 clocks and is simultaneously output. DI denotes the input data of the data register 308 . However, since the output MUXO of the selecting portion 306 is converted into the shift clock SCLK, the data DI shown in FIG. 4 ( c ) is continuously output as shown in FIGS. 4 ( c ) and 4 ( h ) in response to the next 64 clocks. The data DI is not serially latched but is directly output since the shift clock SCLK is used instead of the latch clock LCLK during the test operation.
FIG. 5 is a block diagram showing another preferred embodiment of decoder test controlling apparatus and methods according to the present invention, and also includes a schematic block diagram of FIG. 2 . Referring to FIG. 5, decoder test controlling apparatus and methods according to the present invention include a controlling portion 502 , a shift register 506 , a data register 508 , and an output portion 500 . The output portion 500 includes a decoding portion 510 and a buffering portion 512 . The decoding portion 510 includes a plurality of decoders as shown in FIG. 2 . The buffering portion 512 includes a plurality of buffers as shown in FIG. 2 .
The decoding portion 510 is applied to the 64 contrast levels and 300 channel source drivers like the decoding portion 310 shown in FIG. 3 . However, as described above, the numbers are variable in different decoding systems and methods.
The controlling portion 502 generates the shift clock SCLK in response to the second clock CLK 2 after external input of the start pulse DI 01 , and generates the latch clock LCLK in response to the first clock CLK 1 having a pulse when the second clock CLK 2 has 100 pulses. However, when the test control signal TEST is applied to the decoding portion test controller 504 of the controlling portion 502 , the controlling portion 502 generates the latch clock LCLK and the latch enable signal LEN maintaining a high level, i.e., an output enable level, in response to test control signal TEST.
The shift register 506 serially outputs the shift clocks SCLK that were serially input from the controlling portion 502 through a plurality of output lines. For example, if three input data are simultaneously latched in response to a clock output from the shift register 506 , 100 shift clocks may be used with respect to 300 output channels. Accordingly, the shift register 506 serially outputs first through 100th shift clock through 100 output lines.
The data register 508 continuously inputs six bit data DI 0 through DI 2 through the input terminals IN 1 through IN 3 and serially latches the input data to corresponding memories in response to the first through 100 shift clocks which are a plurality of input control clocks output from the shift register 506 . The data register 508 simultaneously outputs the serially latched data in response to the latch clock LCLK generated from the controlling portion 502 in response to the first clock CLK 1 . When the shift clock SCLK is generated 100 times in response to the second clock CLK 2 , the latch clock LCLK is generated once in response to the first clock CLK 1 .
The decoding portion 510 and the buffering portion 512 operate in a manner corresponding to the decoding portion 310 and the buffering portion 312 shown in FIG. 3, respectively. The decoding portion 510 inputs data that is simultaneously output from the data register 508 and selects voltages corresponding to the respective data among the voltages V 1 through V 64 of 64 levels corresponding to all the bit combinations of the six bit data. The buffering portion 512 temporarily stores the voltages selected from the decoding portion 510 and outputs them as panel displaying voltages through the 300 channels.
The above-described operation of the data register 508 corresponds to normal operation of the apparatus for providing panel displaying voltages, in response to the latch clock LCLK generated from the controlling portion 502 in response to the first clock CLK 1 . Operation of the data register 508 when the decoding portion 510 is tested for a circuit verification in the apparatus for providing panel displaying voltages will now be described.
As mentioned above, the controlling portion 502 generates the latch clock LCLK in response to the first clock CLK 1 during a normal operation. However, when the test control signal TEST is applied to the decoding portion test controller 504 of the controlling portion 502 , the controlling portion 502 generates the latch clock LCLK maintaining a high level and the latch enable signal LEN in response to the test control signal TEST.
The data register 508 latches the data which is input once through the input terminals IN 1 through IN 3 to all the memories in response to the latch enable signal LEN. The data register 508 outputs the data to all the decoders of the decoding portion 510 in response to the latch clock LCLK which is always a high level, whenever a first, second, . . . , or 100th shift clock among the plurality of input control clocks is received from the shift register 506 . Therefore, the data register 508 can output all the bit combinations of the data input through the input terminals IN 1 through IN 3 to all the decoders of the decoding portion 510 while the 64 shift clocks SCLK are generated. Consequently, the data register 508 can reduce the test time by latching data input simultaneously to all the memories and outputting the data to all the decoders of the decoding portion 510 .
FIGS. 6 ( a ) through 6 ( i ) are timing diagrams for testing the decoding portion shown in FIG. 5 . Assume that a point of time in which clocks after first 100 clocks are generated from the shift clock SCLK shown in FIG. 6 ( a ) is a test mode. Then, the latch clock LCLK shown in of FIG. 6 ( b ) maintains a high level, i.e., an output enable level during the test mode.
Data DI shown in FIG. 6 ( c ) is simultaneously output in response to the latch clock LCLK after it is serially latched in response to the first 100 clocks. DI representatively denotes the input data of the data register 508 . However, since the latch clock LCLK continuously maintains the high level, the data DI shown in FIG. 6 ( c ) is continuously output as shown in FIGS. 6 ( d ) through ( i ) in response to the next 64 clocks. Namely, since the latch clock LCLK maintains a high level during the test operation, the data DI is not serially latched but is directly output.
Therefore, the time needed for testing the decoding portion of the apparatus for supplying panel displaying voltages according to the present invention can be reduced to about 2/64 for a decoder for 64 contrast levels and to 2/256 for a decoder for 256 contrast levels compared with the test time in FIGS. 1 ( a ) through ( f ).
A decoder testing method according to the present invention will be described with reference to FIG. 7 . FIG. 7 is a flowchart showing a decoder testing method according to the present invention.
Referring to FIG. 7, it is determined whether the decoders are in a testing mode (Step 702 ). If not, the decoders operate in a normal mode (Step 712 ). The decoders for selecting contrast levels used in the LCD source driver respectively select one among 2 N outputs, i.e., the voltages of the levels corresponding to the respective input data, with respect to the respective N-bit data for displaying the degrees of the brightness of colors with respect to the respective pixels of the panel. During the normal mode, the respective N bit data is serially latched to the memories corresponding to the respective decoders and is simultaneously output to the decoders. Accordingly, the outputs of the respective decoders are simultaneously obtained as panel displaying voltages.
However, when the decoders are determined to be in the test mode in step 702 , N bit input data corresponding to one among all the 2 N bit combinations of the N bit data is selected as test data and is simultaneously latched to all the memories corresponding to the respective decoders (Step 704 ). After Step 704 , the latched test data is output to all the decoders and the data corresponding to the test data is obtained from the plurality of decoders (Step 706 ). After Step 706 , predetermined comparison tests are performed with respect to the data obtained from the plurality of decoders (Step 708 ). Also, it is determined whether tests were performed with respect to all the test data (Step 710 ). If not, the test processes are repeatedly performed.
According to a decoder testing method of the present invention shown in FIG. 7, during the test mode, the N bit data are not serially input and latched to the memories corresponding to the plurality of decoders. Also, the clocks for outputting the test data to all the decoders in the Step 706 have the same timing as that of the clocks used for latching the test data to the memories in the Step 704 or to maintain an output enable level during the test mode of the decoders.
Therefore, it is possible to reduce the time for serially latching the N bit data compared with a normal mode. For example, the time for obtaining 2 N outputs corresponding to the test data formed of 2 N clock time bit combinations from the M decoders is generally L+2 N clock time. Here, L is the value obtained by dividing the number of output channels connected to the M decoders by 3, since the N bit data corresponding to the R, G, and B are simultaneously latched. Accordingly, decoder test controlling apparatus and methods according to the present invention can reduce the time for testing the decoders by controlling the output of the data register for latching the data to be decoded in the front ends of the decoders for selecting contrast levels.
In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims. | A decoding system includes a plurality of decoders, a respective one of which is responsive to respective multibit input data, to decode the respective multibit input data and produce a respective output level corresponding to the respective multibit input data. The same multibit input data is simultaneously applied to the plurality of decoders, in response to a test mode signal. Different multibit input data is then simultaneously applied to the plurality of decoders, so that all of the output levels of the decoders can be tested. The output levels from the plurality of decoders that result from the same multibit input data that is supplied to the plurality of decoders is detected. The detected output levels from the plurality of decoders that result from the same multibit input data that is applied to the plurality of decoders is compared to expected output levels in order to test the decoders. |
CROSS REFERENCE TO RELATED APPLICATION
This application is related to a co-pending application Ser. No. 645,280, entitled, "Datum Reference For Tool Touch Probe System", which is assigned to the assignee of this invention.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to closed loop numerically controlled machining systems and more particularly to a touch probe system and gauging technique therefor.
2. Description of the Prior Art
The technology relating to automated precision machining is developing at a very rapid rate. Systems that are totally dependent on manual operations have largely given way to techniques whereby manufactured parts are made with general purpose, numerically controlled machine systems. Although cutting or other removal of material occurs automatically in such systems, numerous manual operations are still required, primarily for measuring the machined dimensions and for making cutter adjustments using an ordinary numerical control cutter offset. These manual measurements and adjustments of the cutting tool are necessary to take into account a large number of variables, such as: wear of the cutting tool; repositioning and/or replacement of the cutting tool; as well as dimensional changes of the cutting tool, of the workpiece and of the machining apparatus itself due to such factors as heating; deflection under load; etc.
By way of example, in a typical operation carried out with a numerically controlled (NC) machine tool such as a lathe, certain adjustments, e.g. tool offsets, must be manually implemented by the operator after the machine is set up for the manufacture of a particular workpiece or part. Prior to the start of machining the operator must advance the cutting tool to a tool setting surface and determine the tool position by manually measuring the space between the tool and the reference surface. This is normally done with a piece of shim material or the like, and such measurements then form the basis for manually making tool offsets. Where the lathe includes tool holding means such as a multiple tool turret, this operation must be carried out separately for each tool as well as for each of the axes of motion of the machine. Prior to making the final or finishing cut for a particular workpiece surface, the various dimensions of the semi-finished workpiece surface are measured by using a hand-held gauge. This enables the operator to determine the required offset of the cutting tool which is used for the finishing cut. After the finishing cut is made, the workpiece is again checked with the hand-held gauge in order to measure the conformance of the actual dimensions of the finished surface to the desired dimensions.
The manual operations described above are individually time consuming and take up a significant amount of the total time required to machine a particular workpiece to the desired dimensions. This serves to limit the manufacturing capacity of the machine tool. Considering present day costs of a lathe or a milling machine (machining center), any reduction of the capacity of the machine tool becomes a matter of economic significance. Further, all such manual operations further open the manufacturing process to human error.
As is generally recognized, the solution to the foregoing problems is to automate manual measurements and the manual adjustments of the cutting tool, e.g. by the use of a computer operated numerical control system. In such a system the computer may either be positioned remote from the numerical control unit, or it may be incorporated in the latter, e.g. in the form of a microcomputer. Alternatively, a computing capability may be provided remote from the numerical control unit as well as being incorporated into the latter. Instead of downloading successive blocks of data stored on tape or the like, as is the case in an ordinary NC system, a computer numerical control (CNC) system is capable of storing entire programs and calling them up in a desired sequence, editing the programs, e.g. by addition or deletion of blocks, and carrying out the computations of offsets and the like.
Although fully automatic systems have not been widely adopted at this stage of development of the precision machining field, a considerable amount of development work has been done to date, much of it limited to special purpose situations wherein a single machining operation is repetitively carried out. It is also known to mount a sensor in the form of a touch trigger probe on the bed of the machining apparatus, or on a pivotal arm that can be swung out of the way when desired. The position of the cutting tool can be calibrated against such a probe by noting the tool position when contact with the probe occurs. From the observed deviations between the programmed and the actual positions, a compensating offset may be determined and stored in the memory associated with the computer numerical control means. The offset compensates for the difference between the programmed contact position and the actual contact position.
A system and method which incorporates the features described above is disclosed in Allan R. Barlow and William A. Hunter U.S. Pat. No. 4,382,215, entitled, "System And Method Of Precision Machining", issued on May 3, 1983, and which is assigned to the assignee of the present application and incorporated herein by reference. As disclosed in this patent, a touch trigger probe known as a "Renishaw--3 Dimensional Touch Trigger Probe" is mounted in the tool holding means. The latter probe is first calibrated against datum or reference surfaces and is subsequently used to calibrate the tool sensor probe. Only then is the cutting edge of the selected tool calibrated by contact with the tool sensor probe. The initial tool offsets which are determined from the results of this operation are stored in numerical control means. After machining has taken place, the part sensor probe is again calibrated and is then used to probe the machined surface(s) of the workpiece. The information so obtained determines the final offsets required for the finishing cut. Subsequently, the finished surface may be probed to determine its conformance with the desired dimensions. Although simple in construction, the touch trigger probe must be specifically configured for a class of features to be probed. The probes themselves, which are normally purchased as commercial products from specific vendors, tend to be not only expensive but fragile and furthermore cannot reach all cuts.
Another example of touch probing is disclosed in T. Yamamato U.S. Pat. No. 4,195,250, entitled, "Automatic Measuring And Tool Position Compensating System For A Numerically Controlled Machine Tool", issued on Mar. 25, 1987. In this patent a stylus which moves under numerical control is alternately brought into contact with the workpiece. A digital type measuring system is utilized for generating a train of pulses for measurement of the amount of movement of the stylus. Pulse generation is initiated when a voltage level changes when the stylus contacts the workpiece and thus a train of pulses is started and stopped in response to the stylus contact with the workpiece providing a pulse count which is transformed into a measurement of the desired dimension. The overall system complexity is increased by the use of the apparatus employed in the system disclosed in U.S. Pat. No. 4,195,250, and therefore system reliability may be diminished with attendant adverse affects. The cost involved in its implementation is also a major factor.
Accordingly, it is an object of the present invention to provide an improvement in the gauging of machined parts.
It is a further object of the invention to provide an improvement in touch probe systems utilized in closed loop numerically controlled machining systems.
It is another object of the invention to provide a new and improved system for automatically precision machining a workpiece which utilizes apparatus that is relatively simple and economical in construction.
SUMMARY
Briefly, the foregoing and other objects are achieved by means of a non-cutting tool or stylus mounted upon the turret of a numerically controlled machining system such as a lathe. In its preferred form, the stylus comprises a precision carbide ball located at the end of a rod which is secured to a member similar to a tool holder. An accelerometer mounted on the turret picks up "rubbing" vibrations generated as the ball of the stylus rubs against the workpiece as it rotates. The output signals of the accelerometer are coupled to a signal conditioner by means of a rotating coupler where they are thereafter fed to the numerical control and utilized, for example, in measuring a diameter of a workpiece by bringing the stylus into two opposing touch points on either side of the machine tool's center-line and thereafter subtracting the two measurements in a well known fashion to provide the desired measurement. For a certain group of cuts where the stylus may inadvertently touch the side of the groove, a special shape stylus can be used.
BRIEF DESCRIPTION OF THE DRAWING
While the present invention is defined in the claims annexed to and forming a part of the specification, a better understanding can be had by reference to the following description when taken in conjunction with the accompanying drawings in which:
FIG. 1 is a simplified elevational view of a horizontal turret lathe incorporating the features of the subject invention;
FIG. 2 is a simplified top plan view of the turret lathe shown in FIG. 1;
FIG. 3 is a characteristic curve helpful in understanding the operation of the present invention;
FIG. 4 is a partial perspective view of an embodiment of one type of stylus utilized on the turret shown in FIG. 2;
FIG. 5 is a simplified schematic illustration of the manner in which a diameter measurement is made in accordance with the subject invention; and
FIG. 6 is an electrical block diagram illustrative of the electrical signal path between the accelerometer mounted on the turret shown in FIGS. 1 and 2 and the numerical control means shown in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings and more particularly to FIGS. 1 and 2, shown thereat is a simplified illustration of a machining system in the form of a horizontal turret lathe. Typically a turret lathe operates along two mutually perpendicular axes, the X axis and Z axis, with the X axis being designated an axis across the bed of the machine, while the Z axis lies along the length of the bed. As shown, the bed of the lathe includes a frame 10 which carries a pair of guideways 12 and 13 which extend along the Z axis. Parallel to the Z axis is the center line or rotating axis 14 of a lathe spindle 16. A saddle or lateral slide 18 is slidably disposed on the guideways 12 and 13 and is capable of being bidirectionally positioned along the Z axis in either a forward (toward the workpiece, -Z) or reverse (away from the workpiece, +Z) direction. Positioning of the saddle 18 along the Z axis is carried out by means of a lead screw arrangement, not shown, which may be driven by a conventional DC positioning motor arrangement.
The saddle 18, moreover, carries a pair of laterally transverse ways 20 and 21 on which a cross slide 24 is slidably disposed so as to be capable of being positioned along the X axis. Positioning of the cross slide 24 in the X axis is likewise carried out by means of the lead screw arrangement which may be driven by a DC positioning motor. Each of the electric motors or lead screws may have a conventional resolver or encoder coupled thereto adapted to provide a feedback signal indicative of the rotary position of the corresponding component. These feedback signals are representative of the linear position of the saddle 18 and the cross slide 24 along their respective axes. Alternatively, suitable electronic or opto-electronic encoding devices may be used to provide signals directed representative of the linear position of the saddle 18 and the cross slide 24.
A turret 26 is carried by the cross slide 24 and includes a plurality of tool locations 28, each capable of mounting a tool holder or stylus type touch probe holder thereon. In the arrangement shown, the turret 26 is typically capable of mounting eight separate cutting tools or touch probes at tool locations 28. By appropriately indexing, i.e. rotating the turret 26, each tool or probe may be brought into operating position as shown in the drawing. In the embodiment shown in FIGS. 1 and 2, the turret is illustrated for the sake of simplicity in FIG. 2, as carrying a single tool holder 30 including a cutter tool 29 and two stylus holders 31 including two types of stylus probes 32 to be subsequently described.
The bed of the lathe illustrated in FIG. 1 further includes a spindle drive and gear box 34 which is located at one end thereof. The rotatable spindle 16 projects out of the drive and gear box assembly 34 and carries a chuck 36 which includes a set of jaws 38 for holding a workpiece 41. Spindle 16 additionally includes a spindle nose or face 40 which abuts chuck 36. The intersection of the plane of face 40 with the spindle axis or center line 14 defines the original "O" position or origin from which the manufacturer of the particular machine tool establishes machine element and cutting tool locating specifications for use in programming the system. While all program positions are referenced to the origin, the measuring system of the machine tool itself always counts or measures relative to a home position. The latter position is normally located as far away from the spindle nose and center line as saddle 18 and cross slide Z+are able to move.
The chuck 36, in accordance with the known prior art, is configured to include a datum ring having at least a pair of position reference surfaces or datum surfaces which are perpendicular to the X and Z axes, respectively. Each of these surfaces is positioned at a known, calibrated distance from the origin or "O" position. As shown, the external cylindrical surface 42 of the chuck 36 constitutes one reference surface, while chuck face 44 provides the other reference surface. When desirable a special datum post 22 disclosed for example in the above referenced related application U.S. Ser. No. 645,280 may be utilized.
In FIG. 1 numerical control (NC) unit 46 is electrically coupled to a number of different components in the system such as the DC positioning motors, the resolvers, and the acoustic transducer, among other things. The numerical control 46 includes a tape transport 48 which is adapted to store the part and machine control for machining the workpiece. For example, the program may be used to: index the turret; to turn on the coolant required for machining; to rotate the spindle in a selected direction and at a selected speed; to move the probe or tool in a particular sequence of steps for calibration, measuring, for cutting purposes by positioning the saddle 18 and the cross slide 24; and for various other related purposes. The tape may also contain various data such as the desired dimensions of a particular surface which is to be machined as well as the allowable machining tolerance for each dimension and certain parameters which must be taken into consideration depending upon the part which is to be machined and the particular tool or tools to be used, etc.
The numerical control unit 46 may incorporate a computer, such as a microcomputer which responds to stored code words on tape. The microcomputer then causes the appropriate control signals to be issued, e.g. to the DC positioning motors, which will give effect to the tape commands. The microcomputer is also responsive for processing the data acquired through various probing operations and for computing offsets which may produce modifications of the cutting operations carried out by the machining program. All of these functions may be carried out, when desirable, in a remotely located computer, such as in a central computer of a distributed numerical control system so that the processed data is fed to unit 46 which then generates the appropriate control signals. In such an arrangement, the computing capability is normally retained in the numerical control 46.
The data received from the probing operations, feedback data from the resolvers, and data loaded in through the program itself is processed by the microcomputer to compute the aforesaid offsets. Motor control signals derived from the processed data are compared against the position feedback data received from the respective motor resolvers or from other position feedback means. A closed loop system is established in which the differential determined upon comparison of the two signals controls the position of the cutting edge of the tool or position of the measuring probe. The numerical control 46 may also be used to compute, display and print the physical dimensions of the workpiece as well as to compute deviations from the programmed values and display the appropriate allowed machining tolerances. In a preferred embodiment, the numerical control unit 46 is implemented in the form of apparatus which is commercially available from General Electric Company, under the designation Mark Century® 2000 Computer Numerical Control. If a more comprehensive disclosure of the overall operation of the machining system shown in FIG. 1 and the software utilized is desired, one can refer to the above referenced Barlow, et al. patent, U.S. Pat. No. 4,382,215.
In the above referenced related application Ser. No. 645,280 entitled, "Datum Reference For Tool Touch Probe System", the cutting tool itself is utilized as a touch probe and as such is utilized for gauging by sensing contact with the rotating workpiece via an accelerometer vibration pick-up technique. While this system has been found to operate as intended, certain practitioners are reluctant to employ the tool touch probe technique because it is felt that one can still harm the workpiece if the tool is used for gauging.
The present invention, on the other hand, provides a gauging technique which can be used to complement the above-mentioned tool gauging technique by utilizing a non-cutting tool in a location on a turret where a cutting tool normally resides. The non-cutting tool is adapted to merely rub against the workpiece as it rotates as opposed to cutting or gouging the workpiece. A distinction between the two kinds of contact can be detected due to the difference in amplitude and spectral characteristics as evidenced by the characteristic curve shown in FIG. 3. Referring briefly to FIG. 3, a relatively low amplitude noise level exists as random background noise whereas vibrations emanating from the workpiece as a result of the rubbing stylus comprises a relatively constant amplitude signal above the noise level whereas a cutting or gouging of the workpiece results in a relatively higher amplitude signal of varying amplitude. Accordingly, a non-cutting tool, preferably in the form of a stylus such as shown in FIG. 4, and comprising a precision carbide ball 50, having a diameter for example of 3/16 inches secured to the end of a 0.125 inch diameter metal rod 52, is mounted on a holder element 30' which is adapted to be fitted to one of the tool locations 28 shown in FIG. 1. Further as shown in FIG. 4, the rod 52 projects through a bore 54 in the side of the holder 30' and is held in place by means of a metal screw 56 placed in a threaded screw hole 58 formed in the end face 60. Such an arrangement is capable of making a "rubbing" touch against the workpiece 41 by being oriented transverse to the surface of the workpiece 41 or the center line 14 as shown in FIG. 5. When desirable, however, the rod and ball combination can be inserted into the end face 60 to provide a probe which is parallel to the machine center line 14. Both of these arrangements are shown in FIG. 2 being located in adjacent locations of the tool turret 26.
Referring now to FIG. 6, the rubbing signal is picked up as a touch signal by an accelerometer 62 mounted on top of the tool turret and is coupled to the numerical control 46 through a rotating coupler 64, signal conditioning circuitry 66 and interface circuitry 68. Accelerometer 62 may be any one of a number of commercially available devices. For example, a Model No. 1018 accelerometer available from Vibra-Metrics has been found to perform satisfactorily in the present invention. The signal conditioning circuitry includes amplification and band pass filter means as well as discriminator means for eliminating spurious signals. The signal processor circuitry 68 provides an appropriate interface to the numerical control unit 46. It is to be noted that the accelerometer 62 need not be provided with any special coupling to the stylus 32. The accelerometer 62 is simply mounted on the turret 26 such that it picks up, through the turret 26, rubbing vibrations induced in the stylus 32 by contact with the rotating workpiece or datum surface. Furthermore in certain applications, particularly those involving a machining center other than a lathe, the stylus 62 may be rotating while the workpiece remains stationary. Rotation of the stylus 62 would, in that case, be analogous to use of a "line tool" as is well known. What is important is that there be relative motion between the stylus 62 and the contact surface so that "rubbing vibrations" are generated.
The apparatus involving the rubbing stylus type of probe mounted on the tool turret provides a means for making a direct measurement of a part diameter as opposed to being limited to a radius measurement. The inability to directly make diameter measurements is one of the severe drawbacks of known touch probing methods which make use of datum surfaces and a conventional cutting tool as a touch probe.
In measuring a diameter with the stylus type probe, the ball is brought into rubbing contact with the workpiece 40 on both sides of the center line 14 as shown by the phantom depiction in FIG. 5. When contact is made at each side of the workpiece the location of each contact (i.e., the surface of the workpiece) is established within the machine tool's coordinate system. The diameter measurement is then made by a well known subtraction technique for the two probe positions. The calculation is made in the numerical control unit 46. This is a more accurate technique than doubling a radius measurement because it does not require compensation of datum variation due to temperature. This position technique further does not require the cutting tool to be gauged for offset or provided with other means such as reference datum surfaces. The present invention nevertheless provides a machine tool gauging system which permits radius measurements if desired. For example, a radius (or other dimension) of the workpiece can be carried out by first bringing the stylus into contact with one of the datum surfaces (datum surface 42 for radius, datum surface 44 for length, for example) to establish a first position of the stylus surface. This amounts to a calibration of the stylus position since the datum surface location is precisely known within the machine's coordinate reference system. Once calibrated, the stylus is repositioned to touch the rotating workpiece at the point where the radius is to be determined. The stylus position at the point of contact is noted. By taking the difference between the two positions, the radius is determined. The accelerometer 62 (acoustic sensor) detects the rubbing contact at both positions of the probe via rubbing vibrations transmitted through the stylus.
While there has been shown and described what is at present considered to be the preferred embodiment of the invention, modifications thereto will readily occur to those skilled in the art. For example, for certain groove cuts, a special shaped stylus type of rubbing probe may be necessary. It is not desired, therefore, that the invention be limited to the specific implementation shown and described, but it is intended to cover all such modifications, alterations and changes falling within the spirit and scope of the invention as defined in the appended claims. | A non-cutting tool or stylus (32), mounted in a position where a tool normally resides on a turret (26) of a numerically controlled machining system, rubs against the workpiece (41) as it rotates. The rubbing vibrations emanating from the workpiece (41) are picked up as a touch signal by an accelerometer (62) whose output signal is conditioned and fed to the numerical control (46). Diameter measurements, for example, are made directly by touching two opposing points on the workpiece (41) on opposite sides of the machine centerline (14) whereupon a difference calculation is made to provide the required diameter measurement. |
This application is a continuation-in-part of application Ser. No. 519,006, filed Aug. 1, 1983, now abandoned, which is a continuation of application Ser. No. 211,432, filed Nov. 28, 1980, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to devices that are intended to transfer heat from one fluid to another, particularly such devices that are suitable for use in hot gas engines.
2. Description of the Prior Art
Heat is frequently needed to be added to, or extracted from a stream of moving fluid. This is commonly done by heat exchangers which transfer heat between two streams of moving fluid. A common example is in Stirling or hot-gas engines which require three heat exchangers called a heater, cooler and regenerator. The regenerator is a special type of heat exchanger with heat storage capability, and will not be discussed further. Heaters and coolers have design requirements which apply to other types of heat exchangers and include: High efficiency of transfer; controlled resistance to flow of fluid; capability to resist high temperatures and pressures; and, low cost of construction.
Several types of heater exchangers have been developed to accomplish the above design criteria. The methods can be characterized as cylinder heating, finned heat exchangers, tubular heat exchangers, baffle arrangements, and combinations of the above. Additionally, heat pipes have been used with each of the above structures. Construction of a suitable heater has, nonetheless, been one of the primary obstacles to widespread adoption of Stirling or hot gas engines.
The simplest method used is aiming a burner or other heat source at the cylinder of the engine. This method is used with small engines for demonstration purposes. This method has the advantage of low cost and simplicity, but the efficiency of heat transfer is low and the method cannot be scaled up for use in larger engines.
A variation of the above method is accomplished by adding fins to the cylinder to make a finned heat exchanger. This method can also be accomplished by adding a separate finned heat exchanger. The fins add to the efficiency of heat transfer by increasing the area exposed to heat. On the negative side, the addition of fins adds to the cost of construction as they must be welded or brazed to the cylinder or heat exchanger to operate at high temperature. The fins do not affect the pressure handling capability of the device where there is still a trade-off between thin walls for efficient transfer and thick walls for pressure resistance. As a result of the above factors, fins are generally only used in small engines.
The next most common approach has been the addition of a tubular heat exchanger. A tubular heat exchanger usually consists of a series of bent tubes running between the cylinder and regenerator. The tubes are arranged to be exposed to a burner or other heat source. To achieve high thermal efficiency, the tubes should have thin walls. Thin walled tubing, however, is limited in its pressure handling capability. Additionally, the numerous small tubes must be assembled and joined to the cylinder increasing the cost of construction. Nonetheless, tubular heat exchangers are the type most commonly used for larger engines.
Combinations of the above methods have also been used, such as fined tubes. Generally the additional cost of construction outweighs the advantages. One addition frequently used is a heat pipe to convey heat from a small burner to a large heat exchanger structure. A heat pipe is a cavity filled with a vaporizable liquid, such as sodium metal and an inert gas. One portion of the cavity is heated, and the liquid vaporized. This is called the evaporation area. The load is located at another portion of the cavity called the condensation area. At the condensation area, the liquid condenses, transferring its heat of evaporation to the load. The result is a conveying of heat with low loss. The use of heat pipes, however, cannot increase the pressure or temperature capabilities.
Finally, baffle arrangements have been tried alone, or in combination with the other methods. The baffles can increase thermal efficiency, but at an increase in construction cost. In summary, no method has been found that provides high thermal efficiency at low cost with the ability to be exposed to constant high temperatures and pressures at controlled flow resistance.
SUMMARY OF THE INVENTION
An improved heat exchanger is provided by the present invention. The device has the ability to transfer heat to or from a stream of fluid with high efficiency and controlled flow resistance. Ability to withstand continuous high temperatures and pressure is achieved at minimal construction cost. Finally, the device is adaptable to mass production methods.
The device is comprised of at least one annular fluid passage that is surrounded on one or both sides by heating walls. the heating walls are constructed of large diameter thinwall tubing to minimize cost and maximize heat transfer. The thin walls are separated by spacers which allow passage of a second fluid which may be a coolant or heat transfer medium, while providing support to the walls. The spacers are designed to be placed under compression by either multiple annular passages, or annular passages and insulation passages, so that no thick walls of high temperature materials are needed. The device is designed so that all components are cylinders of various sizes with the exception of the ends and manifold block. The device is shown as attached to a Stirling cycle engine as a heater, but it is realized that the invention is equally useable in other applications, or as a cooler. A second embodiment is illustrated which includes a single heating wall for lower cost of construction.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional elevation view of the device in a working environment.
FIG. 2 is a sectional plan view of the FIG. 1 device through line A--A.
FIG. 3 is a sectional plan view of the FIG. 1 device through line B--B.
FIG. 4 is a perspective view of the manifold Block of the FIG. 1 device.
FIG. 5 is a sectional elevation view of a second embodiment of the invention.
FIG. 6 is a sectional plan view of the FIG. 5 device through line C--C.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a sectional elevation view of the device in use as a heater on a Stirling or hot gas engine. This view is a partial sectional view of concentric cylinders and only one side of the assembly is shown for clarity, the other side being identical. As the device is shown attached to an engine, several components of the engine are shown to illustrate the use of the device that are not essential to use of the invention in other heat exchanger applications.
The entire apparatus is enclosed in a pressure shell 1. Pressure shell 1 is of substantial thickness to contain the high pressure fluids within the device and engine. Since pressure shell 1 is not subjected to high temperatures, it may be constructed of any high strength material, such as steel, which has the added advantage of low cost. Within pressure shell 1 is the cylinder 2 of the engine, a displacer 3 oscillates within cylinder 2 of the engine. One end of the cyliner 2 of the engine is constantly exposed to high temperatures and must, therefore, be constructed of a super alloy. Such materials are expensive, but only a thinwall tube is required in this embodiment. The top of cylinder 2 is closed by a cylinder head 6, which, along with cylinder 2 and the top of displacer 3, defines the expansion space 4 of the engine. The only exit from expansion space 4 of the engine is a port 5 which forms the entrance to the heater. Port 5 is shown as an annular opening in this embodiment, but it is realized that equivalent construction, such as holes or slots could be substituted. The exit of the heater is a Regenerator 7. Regenerator 7 is housed between cylinder 2 and an outer wall 8, which is also made of heat resistant material. In operation, gas shuttles between regenerator 7 and expansion space 4, and through the heater under the influence of displacer 3. The purpose of the invention is to transfer heat from an outside source 9 (not shown) to the shuttling gas stream. The device will also work in reverse if the engine is powered by a motor to act as a refrigerator, in which case, heat is transferred from the gas stream to the outside 9.
If the device is used as a heater, outside source 9 is a burner or equivalent heat source, such as radioactive material or solar concentrator. While the preferred embodiments are herein functionally described with reference to heat delivery by means of a heat pipe, it is readily apparent that a pumped heat transfer material, such as a liquid metal, can be substituted for the heat pipe 10 and adjacent structure with minimal modification. Heat source 9 is connected to a heat pipe 10. Heat pipe 10 is a space containing gas and a vaporizable material, such as sodium or potassium metal. Heat source 9 vaporizes the material which then fills heat pipe 10 and areas connected to heat pipe 10. The vaporized material condenses on the walls of such areas, releasing its heat of vaporization to such walls. The above process results in an efficient transfer of heat from source 9 to the walls. Heat pipe 10 enters the device via a hole or annular hole in top plate 11. The junction may be brazed or welded. Top plate 11 forms the top housing of the device and is ring shaped with an inner housing cylinder 12 joined to its inner surface, and a outer housing cylinder 13 joined to its outer surface. The housing cylinders 12, 13 may be joined to top plate 11 by brazing or welding, and are constructed of a high temperature alloy. In this embodiment, inner housing cylinder 12 is joined at its other end to cylinder head 6 by brazing or welding. In another environment a separate flange would replace cylinder head 6. Similarly, outer housing cylinder 13 is attached to the outer regenerator housing 8. Between housing wall 13 and pressure shell 1 is a plurality of layers of multifoil insulation 14. Multifoil insulation 14 is comprised of several layers of heat reflective material, such as nickel separated by layers of an insulating fluid, such as Xenon or carbon dioxide gases. Wall 13 is at a high temperature so insulation is necessary if pressure shell is made of material that cannot be exposed to constant high temperatures. Additionally, if the hot engine gas is operating at high pressure, the counter balancing force of the pressure of insulating gas allows walls 12 and 13 to be constructed of thin wall tubing as there is little pressure differential. This completes the outer housing of the device.
Continuing with FIG. 1 is the internal construction of the device. In this embodiment outer regenerator wall 8 continues into the housing to constitute the outer most heating wall 17 of the device. The annular space 18, between walls 17 and 13, forms the outer annular condenser section of a heat pipe. In this area, during operation, some vapor present in heat pipe 10 condenses, transferring its heat to wall 17. Wall 17 is constructed of thinwall tubing to increase the heat transfer. In a similar manner, an inner condenser section 19 is formed between inner housing wall 12 and an inner heating wall 21. One end of inner heating wall 21 is attached to cylinder head 6 in this embodiment. Finally, a central condenser section 22 is formed between outer central heating wall 24 and inner central heating wall 23. In this embodiment, wall 23 is an extension of cylinder 2 and is joined to wall 24 by a central flange 26. The outer ends of heating walls 23 and 24 are attached to manifold block 27. Walls 21 and 17 are also attached to manifold block 27. Manifold block 27 is sized so that an inner heating area 28 is formed between heating walls 21 and 23, and an outer heating area 29 is formed between heating walls 17 and 24. Communication between the inner heating space 28 and the outer heating space 29 is possible through a passage 35 in manifold block 27. Manifold block 27 also provides several passages 30 for material in heat pipe 10 to enter the central condensing region 22. In summary, it is apparent that all heating walls 17, 21, 23 and 24 are adjacent to condenser regions of the heat pipe 10, therefore, when heat pipe 10 is heated by heat source 9, walls 17, 21, 23 and 24 will rapidly rise to high temperature. All joints are assumed to be connected by welding or brazing, unless otherwise described.
In operation, the fluid pressure in areas 4, 28, 29 and 7 is higher than that in the condenser sections 18, 19 and 22. This pressure differential results in a force tending to collapse the condenser sections. This force is countered by placing spiders 31, 32 and 33 in condenser sections 18, 22 and 19, respectively, and by pressurizing areas 14, 34 and 36 with insulating gas. Spiders 31, 32 and 33 are thus put under compressive stress. Spiders 31 and 33 have passages on the side facing the heating walls 17 and 21 for passage of fluid from heat pipe 10. Inner spider 32 has such passages on both sides. Spiders 31, 32 and 33 can be constructed of any material that is resistant to high temperatures and is strong under compression. Ceramics and glasses are particularly suitable as they can be cheaply molded, but corrugated metal can also be used. In summary, the use of spiders 31, 32 and 33, as integrated into the described heat exchanger, allow low cost construction and high thermal efficiency. These advantages are achieved primarily as a result of allowing thin annular heating walls 17, 21, 23 and 24 by carrying the pressure loads in heating spaces 28 and 29 with the spiders 31, 32 and 33 used in conjunction with pressurized regions 14, 34, and 36.
If used as a heater for a Stirling engine, gas moves through regenerator 7 into outer heating area 29 where the gas is surrounded by heating walls 17 and 24, which heat the gas. The gas then proceeds through the passage 35 in manifold block 27, and into inner heating area 28. In area 28 the gas is surrounded on both sides by heating walls 21 and 23, and is heated further. The hot gas then exits through port 5 into expansion space 4. When displacer 3 moves toward cylinder head 6, the gas returns through port 5 into space 28, 35, then 29, and returns to regenerator 7. From the above description, it is apparent that the device can work in either direction. In addition, if the engine is used as a refrigerator, heat can be extracted from the gas and transferred to a heat sink at 9. It should be noted that the device is normally operated in a position inverted to that shown in FIG. 1, so that condensed fluid in heat pipe 10 returns to the vicinity of heat source by gravity. However, heat pipe operation when oriented as shown, is possible by utilizing metal wicking (not shown), such as wire mesh screens attached to the condensation walls so that capillary action returns the condensate to the heat source 9 through heat pipe 10. Finally, it should be noted that the device can also operate as a cooler, if heat pipe 10 and areas 18, 19 and 22 are filled with a cooling fluid.
FIG. 2 is a plan section view along line A--A of FIG. 1. This figure clearly shows the circular nature of the device, although only a segment of each circle is shown, it being realized that the device is symmetrical. Pressure shell 1 surrounds the device and is filled with high pressure insulation gas in regions 14 and 36. Area 14 may also be filled with multifoil insulation as described above. Next, is outer housing wall 13, which along with outer heating wall 17, defines the outer condensing section of the heat pipe. Spider 31 fits between walls 13 and 17, and provides a plurality of pillars for transmitting compressive forces between walls 13 and 17. The area between pillars 41 forms channels which constitute the condensing section 18 of the heat pipe. The outer heating passage 29 is seen to be an annular section between heating walls 17 and 24. The central condenser section is similar to the outer condenser section except that condensing section passages 22 are formed on both sides of spider 32. It should be noted that spider 32 is designed to provide unbroken pillars between walls 24 and 23. The inner condensing section is formed similar to, but in reverse of, the outer condensing section, with inner heating wall 21, spider 33 and inner housing wall 12. The inner heating area 28 is thus formed between heated walls 21, 23 and is also seen to be an annular space. Finally, the central area 36 of the device is filled with a compressed insulating gas that supports inner housing wall 12 against the compressive forces transmitted to it from inner heating area 28 through heating wall 21 and spider 33.
FIG. 3 is a sectional plan view of line B--B of FIG. 1. Line B--B passes through the passage 35 between annular heating areas 28 and 29. Parts 1, 14, 13, 31, 17, 29, 28, 21, 33, 12 and 36 are substantially identical to those in FIG. 2. It is apparent that the fluid flows from outer heating passage 29 through area 35 and into inner heating passage 28. Flow in the reverse direction is also possible. It will be seen that passage 35 is formed by the spaces between a series of tubes 42, the interiors of which form passages 30. A portion of the central spider 32 can be seen through passages 30. As passages 30 area is also filled with hot vaporized liquid, additional heat transfer can occur in this cross over region. Tubes 42 must be sufficiently thick to contain the pressure differential between areas 30 and 35, but this is the only high temperature portion of the device that may require thicker walled tubing, although the relatively small diameter of the tubes minimizes this potential problem.
FIG. 4 is a detail of the manifold block of the invention. Only half of manifold block 27 is shown to allow view of sections through passages 30 and 35. Manifold block 27 is comprised of a top flange 47, a bottom flange 43, and a series of tubes 42. The interiors of tubes 42 form a passage 30, and the area defined by the top of flange 43, the bottom of flange 47 and the areas between tubes 42 form passage 35. In the construction shown in FIG. 4, flanges 43 and 47 are provided with holes to accept tubes 42. This construction would be used if manifold 27 is constructed by welding. Manifold block 27 could also be made by casting or electroforming, in which case it would be one piece. Lower flange 43 provides an outer surface 44 to accept and join to outer central heating wall 24 and a surface 46 to accept and join to inner central heating wall 23 as shown in FIG. 1. Similarly, top flange 47 provides surfaces 48 and 49 to accept and join to outer heating wall 17 and inner heating wall 21 respectively. The radial distance between surfaces 44 and 48, and between 49 and 46, determine the size of passages 28 and 29. The size of passages 28 and 29 determines the resistance to flow of the device. Manifold block 27 provides a simple means to adjust the flow resistance to a pre-determined value.
FIG. 5 is a section elevation view of a second embodiment of the invention. In this embodiment, the device is surrounded by a pressure wall 101 and insulation 114 in a manner similar to the FIG. 1 embodiment. The device is shown connected to a Stirling engine as in the FIG. 1 embodiment. The regenerator of the engine is shown at 107 and a piston 103 is near the top 106 of cylinder 102. Spaces 114, 134 and 136 are pressurized with insulating gas as in the FIG. 1 embodiment. A heat pipe 110 is connected to a source of high temperature and is filled with a conductive media such as sodium vapor. The conductive media is contained between an outer annular containment wall 113 which also serves as an outer wall for regenerator 107 and an inner annular containment wall 112 which are connected to heat pipe 10 by a top cap 111. A bottom cap 126 seals to outer containment wall 113 and an outer heater wall 117. An inner heater wall 121 is connected to outer heater wall 117 by a heater top cap 147. In this embodiment, inner heater wall 121 and inner containment wall 112 are sealed to cylinder head 106. It is thus apparent that the conductive media area between walls 113 and 117 and caps 126 and 111 is connected to the area between walls 121 and 112 and cap 111 and cylinder top 106. An interior non-heated wall 102 protrudes into the annular space between heater walls 117 and 121 to divide this area into inner and outer annular heat spaces 128 and 129, respectfully. Spaces 128 and 129 are connected by a passage 135. The result is a long path for gases circulating between regenerator 107 and the space 104 between piston 103 and cylinder top 106. Ceramic or metal spacers 131 and 133 between walls 113 and 117 and 121 and 112, respectively, allow heater walls 117 and 121 to be thin for good heat transfer. Spacers 131 and 133 include passages 118 and 119, respectively, for passage of the conductive media.
In use, since the passages 118 and 119 are filled with condensing conductive media, heater walls 117 and 121 are rapidly heated to a temperature similar to that of heat pipe 110. Any gas flowing between regenerator 102 and area 104 must thus pass along the entire length of heating walls 117 and 121 and is thereby heated with high efficiency.
FIG. 6 is a partial plan section view along line C--C of FIG. 5. This figure shows the annular nature of the invention. An outer pressure shell 101 surrounds the device. Multifoil insulation 114 filled with pressurized insulating gas is adjacent to shell 101. Outer containment wall 113 and inner containment wall 112 enclose the hot portion of the device and are adjacent to and in contact with ceramic spiders 131 and 133, respectively. Spiders 131 and 133 include passages 118 and 119 for the conductive media. Outer heating wall 117 and inner heating wall 121 also contact spiders 131 and 133. A wall 102 divides the space between heating walls 117 and 121 into two passages 129 and 128. In operation, area 136 and the vicinity of insulator 114 are filled with pressurized insulating gas. Passages 129 and 128 are filled with pressurized working fluid. Since the conductive media in passages 118 and 119 is at a lower relative pressure, spacers 131 and 133 are under constant compressive stress. Use of ceramic for spacers 131 and 133 allows use of thin walls for heater walls 117 and 121 due to its high compressive strength. Other materials having similar characteristics may be substituted for ceramics.
It will be understood that the invention may be embodied in other specific forms without departing from the spirit of the central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details thereof, but may be modified within the scope of the appended claims. | A heat exchanger having annular construction for a constant operation at high temperatures and pressures. A series of heating walls at high temperature surround the fluid to which heat is desired to be transferred in annular spaces. Counterbalancing pressures in areas filled with high pressure fluid and insulating gases allow use of thinwall construction for the heating walls to reduce cost and increase heat transfer. Spacers that are placed under compression are provided to maintain dimensional stability and transmit forces. Embodiments describing the use of the device as a heater or cooler and operation in either direction are illustrated. A second embodiment illustrates a heater with single sided heating of the fluid desired to be heated. |
TECHNICAL FIELD
The present invention relates broadly to the field of apparatus for mounting a rotary cutting tool to a rotatably driven spindle to translate the motion of the spindle to the tool. More specifically, the invention relates to apparatus for providing means to adjust the eccentricity of the tool's design axis of rotation relative to the axis of rotation of the spindle. In a preferred embodiment of the invention, this goal is accomplished without introducing any canting of the tool relative to the rotational axis.
BACKGROUND OF THE INVENTION
Various types of rotatably driven cutting tools are known and typically used in performing machining functions. These include twist drills, boring bars, milling cutters, screw thread taps, reamers, etc. Typically, such tools are mounted to the spindle by use of means such as three-jaw chucks or other similar apparatus. Such devices are available commercially and function to translate the rotational motion of the spindle to the tool.
Such chucks serve well to mount a tool particularly when close tolerances are not required. When close tolerances are necessary, however, they frequently prove inefficient for various reasons.
Even with a brand new chuck, an eccentricity of 0.0050 inches can be present between the tool's design axis of rotation and the axis of rotation of the driving spindle. While such eccentricity might be acceptable in some applications, it might prove grossly unacceptable in others.
This problem is further exacerbated by non-uniform wear of grasping surfaces of the jaws after periods of use. Normal wear of the rotatably driven tool grasping chuck surfaces does not proceed uniformally. Thus, axial eccentricity of a rotating cutting tool grasped and driven by the jaws of a chuck typically increases with time of use of the chuck. This is particularly true if the rotating cutting tool should slip within the grasp of the chuck jaws because they are insufficiently tightened to fully resist the torque required by the tool. After a period of time, therefore, even if the gripping jaws were perfectly machined when the chuck was new, the chuck loses its ability to receive and clamp in a precisely centered fashion the driving shank of the tool.
As can be seen, therefore, a central longitudinal axis of a tool such as a twist drill, for example, can easily become spaced at a distance from the axis of rotation of the spindle by which the tool is driven. The tool will, therefore, be made to orbit the spindle's axis of rotation. The hole drilled by such a tool will have a radius equal to the radius of the tool plus the dimension of eccentricity.
Rotary cutting tools are typically provided in certain standard sizes. On occasion, although infrequently, a machinist might be required to make a cut sized between two standard sizes. Rather than being required to obtain a specially constructed tool for this purpose, the cut can be made by rotating the next smaller sized tool eccentrically. That is, the axis of the tool can be displaced from the axis of rotation of the driving spindle by design in order to accomplish the desired cut.
Various structures have been devised to solve these problems in the prior art. For example, U.S. Pat. No. 3,088,746 (Highberg et al) illustrates a RADIALLY ADJUSTABLE CHUCK providing four set screws to forcibly displace the chuck and its grasping jaws assembly to a position at which the axis of the chuck is alligned with the axis of rotation of a driving spindle. Such structures, however, do not ensure that the axis of the tool, once adjusted by the set screws, is a precisely parallel extension of the axis of rotation. While the location of the axis might be adjusted radially, the device of Highberg et al does not provide means for ensuring that the tool's axis does not become canted relative to the rotational axis of the drive spindle. Consequently, rather than solving the problems which the device addresses, the Highberg et al structure can exaggerate them.
The present invention is a device directed to the solving of all of the problems existent in the prior art. It is an improved eccentricity adjustment device which not only adjusts the radial placement of the axis of the tool relative to the spindle's axis of rotation, but it also functions to effect parallelism between the tool's axis and the rotational axis of the spindle.
SUMMARY OF THE INVENTION
The present invention is a device for adjusting the eccentricity of a rotatably driven tool with regard to the axis of rotation of a driving spindle. The device includes a male member having a hub with an outer surface, generally circularly cylindrical with regard to an axis parallel to the axis of rotation of the spindle, and a shoulder at one axial end thereof. Further, the device includes a female member which has an annular wall circumscribing a cavity therewithin. The cavity has a diameter slightly larger than that of the hub of the male member, and the hub can, thereby, be received within the cavity. When the hub is inserted into the cavity, an axial end of the annular wall can engage the shoulder of the male member so that, when the axial end of the female member annular wall is in full engagement with the shoulder, the axis of the male and female members are parallel. Means are provided for concurrently adjusting the relative radial positioning of the male member relative to the female member and urging the distal axial end of the female member into tight engagement with the shoulder of the male member. The parallelism of the axes of the male and female members can, thereby, be ensured. Means are provided for mounting either the male or female member to the spindle for rotation therewith, and the cutting tool to be driven rotatably is attached to the other of the male and female member.
In a preferred embodiment, the outer surface of the hub can be provided with a plurality of circumferentially spaced and aligned generally planar surfaces. Similarly, the annular wall of the female member can be provided with a corresponding number and positioned protuberances which can be disposed for radial reciprocation. The planar surfaces formed in the outer surface of the hub can be angled so that, as the protuberances are urged radially inwardly, engagement of the protuberances with the planar surfaces and movement therealong will deflect the female member axially relative to the male member so that the distal axial end of the female member annular wall is brought into tight engagement with the shoulder of the male member.
It is envisioned that reciprocation of the protuberances would be effected by providing a plurality of apertures in the annular wall of the female member at the desired protuberance locations. Each location could be provided with female threaded surfaces. The outer surfaces of the protuberances would be male threaded, and reciprocation would be effected by selectively turning the protuberances to accomplish desired adjustments.
The protuberances could take the form of dog point set screws which, when screwed radially inwardly, would engage the planar surfaces formed in the hub. If desired, the axis along which a particular set screw would move could be made to be generally perpendicular to the planar surface in the hub with which the set screw would come into engagement.
The present invention envisions incorporating means for retaining the male and female members together in one assembly even when the dog point set screws are withdrawn radially. The hub can be provided, in an outer surface thereof, with an annular groove. Similarly, an inwardly facing surface of the female member annular wall is provided with a groove having an axial dimension similar to that of the groove in the male member hub. When the axial end of the annular wall is in engagement with the shoulder of the male member, at least a portion of the groove in the female member annular wall would be in registration with the groove in the male member hub. An appropriatly sized and shaped snap ring could be fitted into the registered grooves in order to accomplish the goal of maintaining the male and female members together in a unitary assembly even when the set screws are withdrawn radially. It will be noted that the axial dimension of the snap ring would be smaller then the axial dimension of at least one of the grooves so that relative axial movement of the male and female members will be permitted in order to permit the urging of the distal axial end of the female member into tight engagement with the shoulder of the male member.
Alternatively, the hub can be provided, in an axial end opposite that at which is positioned the shoulder, with a deformable annular lip. As the hub would be inserted into the cavity in the female member, the lip would be brought into engagement with a base of the cavity. The lip could be provided with a convex surface to engage the base so that, as force would be exerted upon the hub, the convex surface would function as a rolling fulcrum to divert the lip radially outwardly and into an annular groove formed in the inner surface of the female member wall proximate the base thereof. Once the lip was deformed into this groove, the two members would be maintained as an assembly. The axial dimension of the groove would, of course, be slightly larger than the axial dimension of the lip in order to permit relative axial movement of the members so that the distal end of the female member wall could be brought into tight engagement with the male member shoulder.
The present invention is, thus, an improved eccentricity adjustment device. More specific features and advantages obtained in view of those features will become apparent with reference to the DETAILED DESCRIPTION OF THE INVENTION portion of this document, the accompanying claims, and the appended drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the present invention and a typical three jaw chuck mounted to the female member thereof, some portions being broken away, in combination with a driving spindle, a tool, and a dial indicator and axial displacement measuring device;
FIG. 2 is an exploded elevational view of the preferred embodiment of the invention showing all components before assembly, some portions being broken away;
FIG. 3 is a partial sectional view of the preferred embodiment showing an assembly jig holding the female component and illustrating force being applied to the male member during assembly;
FIG. 4 illustrates, in a sectional view, an alternative embodiment for securing the male and female members into one assembly utilizing a hexagonal snap ring;
FIG. 5 is a view taken generally along the line 5--5 of FIG. 4;
FIG. 6 is a sectional view illustrating a different method by which the male member can be mated to the drive spindle;
FIG. 7 is a diagrammatic view showing relative radial adjustment positioning of the female member relative to the male member.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings wherein like reference numerals denote like elements throughout the several views, FIG. 1 illustrates a preferred embodiment of the present invention in combination with a rotatably driven spindle 10, a twist drill bit 12 (illustrative of various tools with which the invention can be used), and a typical three-jaw chuck 14 mounting the bit 12. The chuck 14 is one of a type known in the art and presently commercially available.
The drive spindle 10 is made to rotate about an axis (not shown in the figures). The present invention functions to either reduce or increase the eccentricity of a central longitudinal axis 16 of the tool 12 with respect to the axis about which the spindle 10 is driven. If it is desired that the axis 16 of the tool 12 be aligned with the axis of rotation of the spindle 10, adjustments are made by use of the present invention in a manner as will be seen hereinafter in order to reduce the eccentricity to zero. If, on the other hand, for example using a twist drill, it is desired to bore a hole slightly larger than one which could be made using a standard size drill, the axis 16 of the tool 12 could be offset so that the sum of the radius of the tool 12 and the eccentricity provided would total the desired radius of the hole to be bored. Eccentricity can be ascertained in any appropriate manner. FIG. 1 illustrates an axis offset measuring device 18 having a dial indicator 20 by which eccentricity can be measured. It will be understood, however, that any appropriate means for measuring eccenrtricity can be employed.
Referring now to FIG. 2, the present invention includes a male member 22 and a female member 24. The male member 22, as illustrated in the figures, is matable to the drive spindle 10. As will become more apparent with reference to disclosure made hereinafter, however, the female member 24 could, equally as well, be designed to be mated to the drive spindle 10.
Mating of the male member 22 to the spindle 10 can be accomplished in a number of ways. FIG. 2 illustrates a shank 26 which can be fitted into an aperture 28 in the spindle 10 and be secured there by appropriate means. Securing can be effectuated by providing a locking taper fit between the shank 26 and an inner surface of the aperture 28 in the spindle 10, by collet chuck, or by other appropriate means. FIG. 6 illustrates an alternative securing means. Because of the high frictional torque characteristics of "self-holding" tapers used, it may not be necessary to provide splines and keyways in order to insure that rotational motion of the spindle 10 is translated to the male member 22, but splining can be provided, if desired.
The male member 22 further includes a hub portion extending downwardly from the shank 26. As seen in the figures, the hub 30 has an outer surface 32 which demarks the diameter of the hub 30. The male member 22 is provided with a flange-like portion 34 intermediate the shank 26 and the hub 30. While the hub 30 is shown as having a diameter larger than that of the shank 26, the flange-like portion 34 extends radially even beyond the outer surface 32 of the hub 30 in order to define a shoulder 36.
FIG. 1 illustrates the female member 24 as having a tapered shank 38 extending in an axial direction and receivable within a correspondingly tapered aperture 40 in the typical three-jaw chuck 14. As in the case of the shank 26 of the male member and its mating to the drive spindle 10, any appropriate means for securing the female member shank 38 and the chuck 14 together in order to effect translation of rotational motion can be utilized.
The female member 24 has, extending upwardly from the shank portion 38 as seen in FIG. 2, an annular wall 42 with an inner surface 44 circumscribing a cavity 46 within the wall 42. The diameter of the cavity 46 is larger than that of the hub portion 30 of the male member so that the hub 30 can be received within the cavity 46. The invention provides for diametral clearance spacing between the outer surface 32 of the hub 30 and the inner surface 44 of the female member wall 42 so that the male member 22 and female member 24 can be adjusted laterally relative to one another. As can be seen, then, by adjusting the female member 24 relative to the male member 22, the longitudinal axis 16 of the tool 12 can be moved relative to the axis about which the drive spindle 10 rotates in order to adjust eccentricity.
FIG. 7 illustrates how this lateral adjustment of the male member 22 relative to the female member 24 can be effectuated. That figure shows four dog point set screws 50 passing radially through the annular wall 42 so that inner ends 54 enter into the cavity 46 to impinge upon the hub portion 30 of the male member 22. With the set screws 50 in their positions as indicated in FIG. 7, hub 30 is generally concentric with the annular wall 42, and their centers generally coincide at index 56. If the set screw 50 approaching center from the upper left quadrant, as viewed in FIG. 7, is withdrawn and the set screw approaching center from the lower right quadrant, as viewed in FIG. 7, is moved radially inwardly, hub 30 will become offset so that its center is displaced to index 58. Similarly, if the set screw 50 approaching center from the lower left quadrant, as viewed in FIG. 7, is withdrawn and the set screw 50 approaching center from the upper right quadrant, as viewed in FIG. 7, is moved radially inwardly, hub 30 will be displaced to index 60. Various combinations of adjustments can be made to position the hub 30 relative to the annular wall 42 so that a desired eccentricity is achieved.
The invention employs the set screws 50 for adjusting the male and female members 22, 24 relative to one another and concurrently urging an axial end 48 of the female member wall 42, distal with respect to the three-jaw chuck 14, toward the flange portion 34 carried by the male member 22 and into tight engagement therewith. The shoulder 36 formed by the flange portion 34 of the male member 22 defines a plane which is substantially normal to a central axis of the male member 22, and the distal end 48 of the female member wall 42, similarly, defines a plane generally normal to the axis of the female member 24. Consequently, by bringing the axial end 48 of the female member 24 into tight engagement with the male member shoulder 36, the axes of the male and female members 22, 24 are made to be substantially parallel. By so doing, the axis 16 of the tool 12 will be made to be substantially parallel to the axis about which the spindle 10 is driven. Consequently, canting of the tool 12 will be precluded.
The male member hub outer surface 32 is provided with a plurality of faceted surfaces 62 corresponding in number and location to the dog point set screws 50 carried by the female member 24. When the hub 30 is received within the cavity 46 defined by the female member wall 42, the faceted surfaces 62 on the hub outer surface 32 can be brought into registration with the locations of the set screws 50. By adjusting the set screws 50 radially inwardly toward the hub 30, the inner ends 54 of the screws 50 impinge upon the faceted surfaces 62.
Typically, the faceted surfaces 62 would be planar and, in the preferred embodiment, would be at an angle of approximately 5 degrees to an axis of the male member 22 with respect to which the outer surface 32 of the hub portion 30 is circularly cylindrical. The surfaces 62 would angle toward the axis as they approach the flange portion of the member 22.
As the set screws 50 are rotated to move radially inwardly, the inner ends 54 of the screws 50 will engage their corresponding faceted surfaces 62. As the set screws 50 are rotated additional amounts to move them inwardly, the inner ends 54 of the screws 50 will tend to seek out that portion of the faceted surface 62 which is deepest with respect to the inward movement of the screw 50. Because of the structuring and angling of the faceted surfaces 62, these "deepest" locations will be at extremities of the faceted surfaces 62 closest to the flange portion 34. As a result, as the set screws 50 move radially inwardly, they will be deflected toward the flange portion 34 and, concurrently, "drag" the female portion 34 in that direction. The axial locations of the apertures 52 through which the dog point set screws 50 reciprocate and the faceted surfaces 62 are such that the distal axial end 48 of the female member wall 42 will, in fact, engage the shoulder 36 defined by the flange portion 34 and be able to be urged tightly into engagement with the shoulder 36.
As will be appreciated, movement of the set screws 50 can be along a perfectly radially extending path, since the engagement of the faceted surfaces 62 by the ends 54 of the set screws 50 will effect the axial movement of the female number 24 relative to the the male member 22 irrespective of the angle of attack of the set screws 50 against the faceted surfaces 62. It is deemed to be optimum, however, if the set screws 50 are reciprocable along paths normal to their respective corresponding faceted surfaces 62. The set screws 50, as seen in the figures, therefore, reciprocate along paths at an angle of 85 degrees relative to the axis with respect to which the inner surface 44 of the female member wall 42 is circularly cylindrical.
The inner end 54 of each set screw 50 can be provided with a generally planar surface for engaging its corresponding faceted surface 62. Such a planar surface can be substantially perpendicular to the axis along which the set screw 50 reciprocates. With the axis of reciprocation generally perpendicular to the planar faceted surface 62, the planar surface of the corresponding set screw 50 will be parallel thereto. When the inner ends 54 of the set screws 50 are brought into engagement with the faceted surfaces 62, therefore, a "wrench" effect will be created so that rotation of the male member 22 will be translated to the female member 24.
Because an assembly comprising the male and female members 22, 24 is subjected to significant vibration during the operation of the particular machine, nylon pads (not shown) can be applied to the threads of the set screws 50 in order to be able to adjust the screws 50 and rely upon their being maintained in the desired position. With the screws thus maintainable, indicia (not shown) can be provided on the outer surface of the female member wall 42 in order to be able to determine the radial positioning of the screws 50 and, consequently, the eccentricity being provided.
As seen in the figures, the faceted surfaces 62 formed in the outer surface 32 of the hub portion 30 of the male member 22 are recessed to receive the dog point set screws 50. By so structuring the male member 22, a machine operator need not rely upon merely the "wrench" effect created by engagement of the planar sufaces at the ends 54 of the set screws 50 with the faceted surfaces 62 to insure safe translation of rotational motion from the male member 22 to the female member 24. With the faceted surfaces 62 being recessed, side walls 66 of the recesses can engage side walls of the set screws 50 to achieve a splining effect. As a result, even if set screws 50 should become withdrawn somewhat, translation of rotational motion to the female member 24 will still be insured.
Means are provided to prevent the entry of metal chips between the axial end 48 of the female member wall 42 and the shoulder 36 defined by the flange portion 34 of the male member 22 in order to preclude scoring of the various internal surfaces. This is accomplished by placement and receipt of a resilient O-ring seal 64, resistent to oil and machining coolant, within an annular channel 65 formed in the distal axial end 48 of the female member wall 42.
As will be perceived, as the dog point set screws 50 are withdrawn radially outwardly so that they do not extend inwardly beyond the inner surface 44 of the female member wall 42, the male and female members 22, 24 would be free to diverge from one another and separate. Although these members are, of course, manufactured separately,, it is desirable that, once they are used in combination, they would be maintained together in a unitary assembly. By being so maintained, the chances are less likely of misplacing one of the members, and the seal between the distal axial end of the female member wall 42 and the shoulder 36 of the male member flange 34 can be maintained in place.
FIGS. 4, 5, and 6 illustrate the use of a snap ring 86 for maintaining the male and female members 22, 24 in an assembly. As seen in FIGS. 4 and 6, registered annual grooves 88, 90 can be formed in the outer surface 32 of the hub 30 and the inner surface 44 of the female member wall 42, respectively. An appropriately sized and shaped snap ring 86 can be positioned in the groove 90 in the wall 42 of the female member 24, and the hub 30 can then be urged into the cavity 46 in the female member 24. Because of resiliency afforded to the snap ring 86 and the discontinuity 92 therein at a location about its perimeter, the ring can be deformed outwardly in groove 90 as the hub 30 enters cavity 46. As the groove 88 achieves the axial location of the ring 86 received in groove 90 in the female member wall 42, it will snap inwardly into groove 88. To facilitate camming of ring 86 outward into groove 90, hub 30 can be radiused as at 93. The male and female members 22, 24 will then be held together in assembly.
In order to facilitate the inward deformation of the ring 86 to allow it to be positioned in groove 90, the entrance to the cavity 46 can be provided with annular beveling 94. By so structuring the entrance to the cavity 46, "camming" action will occur to urge the ring 86 inwardly.
As seen in FIG. 5, a generally hexagonally shaped snap ring 86 is contemplated as being used in this embodiment. It will be understood, however, that snap rings configured in other fashions will also serve to accomplish the intended function.
As seen in FIGS. 4 and 6, the groove 90 formed in the female member wall 42 has an axial dimension greater then does the groove 88 formed in the hub 30. While the snap ring 86 may be dimensioned closely to the axial dimension of the groove 88, the larger axial dimension of the groove 90 will afford some measure of relative axial movement between the male and female members 22, 24. As a result, the urging of the axial end 48 of the female member 24 into tight engagement with the shoulder 36 defined by the flange portion 34 of the male member 22 will not be precluded.
FIGS. 2 and 3 illustrate an alternative embodiment of the mating means. The inner surface 44 of the female member wall 42 can be provided, at an axial end of the cavity 46 opposite the end from which the male member hub 30 enters the cavity 46, with an annular groove 68. This grove 68 would be proximate a base portion 70 of the female member 24.
A bottom surface 72 of the male member hub 30 can carry a deformable lip 74 annular in structure. The lip 74 extends downwardly and outwardly from the location on the hub 30 from which it exits. Prior to the hub 30 being inserted into the cavity 46, the extremity 76 of the lip 74 would be within an imaginary cylinder extending from the hub 30 so that the lip 74 would not preclude insertion of the hub 30 into the cavity 46.
The downward and inwardly facing surface of the lip 74 is illustrated as being convex as at 78 and would, optimally, be provided with a substantially constant radius of curvature. As the hub portion 30 of the male member 22 is inserted into the cavity 46, this convex surface 78 would be first to engage the base portion 70 of the female member 24 and would function as a "rolling fulcrum" on which the lip 74 would turn in deforming outwardly into the annular groove formed in the inner surface 44 of the female member wall 42.
FIG. 3 illustrates a manner in which the male member 22 could be married to the female member 24. An under surface 80 of the base portion 70 of the female member 24 could be seated on a jig 82 specially provided to receive the female member 24. With the female member 24 so seated, the male member 22 could be made to approach the female member 24 and the hub 30 enter the cavity 46 formed within the wall 42 of the female member 24. As pressure is applied downward as indicated by the arrow 84, the convex surface 78 of the lip 74 could function as the "rolling fulcrum" previously described, and the lip 74 would deform radially outwardly into the groove 68. With the lip 74 so deformed, the male and female portions 22, 24 would be retained together as a unitary assembly.
As seen in FIG. 1, the axial dimension of the groove 68 would be greater than the axial dimension of the lip 74 as measured once the lip 74 is deformed and received within the groove 68. As a result, even though the male and female members 22, 24 are integrated into a unitary assembly, some relative axial movement of the male member relative to the female member 22 is permitted. Consequently, the urging of the distal axial end 48 of the female member 24 into tight engagement with the shoulder 36 defined by the flange portion 34 of the male member 22 will not be precluded.
Each of FIGS. 1, 2, 4, and 6 illustrate a series of threads 96 formed in the upper extremity of the downwardly extending shank 38 which is to be mated with the three-jaw chuck 14. FIG. 1 illustrates a collar threaded onto this structure. Such a collar can be used to facilitate removal of the chuck from the female member 24 when, for example, the user of the implement desires to change the tool 12. By rotating the collar 98 so that the threads 96 urge it downwardly, the collar 98 is brought to bear upon the upper end of the chuck 14, and as the collar 98 is continued to be rotated to move it downwardly, mechanical advantage will be obtained to push the chuck 14 out of engagement with the female member 24.
The present invention can be made from one of various materials suited to applications of the particular type of device. It may be constructed of many carbon or alloy steels, depending upon the strength and resistence to damage required in actual practice. It has been found that SAE 1117 leaded, free machining steel, surface hardened by carbonizing or nitriding by treatment by the Kolene Corporation Melanite® QPQ process is a preferred material.
Numerous characteristics and advantages of the invention for which this application has been submitted have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, choice of material, and arrangement of parts without exceeding the scope of the invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed. | The present invention is a device for adjusting eccentricity of the design axis of rotation of a rotary tool (12) with regard to the axis of rotation of a drive spindle (10). The device includes male and female members (22, 24), one matable to each of the spindle (10) and the tool (12). The male and female members (22, 24) are adjustable relative to each other to vary the eccentricity and to maintain the tool (12) wherein it is not canted relative to the axis of rotation of the spindle (10). |
CROSS REFERENCE TO RELATED APPLICATIONS
The present invention benefits from U.S. application 60/992,589 filed 5 Dec. 2007 and is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
The present invention relates to current sensing in electronic circuitry and specifically to a device and method for current sensing in a switching power converter.
DESCRIPTION OF RELATED ART
Reference is made to FIG. 1 which illustrates the conventional current sensing circuit of US 2008/0246460. US 2008/0246460 illustrates a conventional current sensing circuit 202 coupled to switching field-effect-transistors (FET) high side FET 210 , and low side FET 206 within a switching regulator. The current-sensing-circuitry 202 is configured to bypass a small sense current 208 from the conducting current 209 of the switching-FET according to a sense ratio. The conducting current for the switching regulator is controlled by a control signal. Current sensing circuit 202 includes a sensing FET 204 which is coupled in parallel with low-side FET 206 . Control logic 306 provides control signals to low-side FET 206 , high side FET 210 and current sensing FET 204 . More specifically, the drains and gates of both sensing FET 204 and low-side FET 206 are tied together. Hence, the same control signal that controls low-side FET 206 also controls sensing FET 204 . The source of low-side FET 206 is connected to the ground while the source of sensing FET 204 is used as the output node. Although the sources of the two FETs are not tied together, it is desirable that they have the same voltage. US 2008/0246460 describes a technique that sets the source voltage of sensing FET 204 to be the same as the source voltage of low-side FET 206 below. Sensing FET 204 conducts a sense current 208 , which is a small fraction of a main switching regulator current 209 conducted by low-side FET 206 . The ratio between main switching regulator current 209 and sense current 208 is proportionate to a predetermined large number, e.g. greater than 500.
A characteristic of conventional current sensing circuit 202 is that sense current 208 is supplied by main current 209 of the switched power circuit. Similarly, another well established technique to sense current is to place a small sense resistor in series with the power train (for example on the ground rail) and measure the voltage drop across the sense resistor and thus estimate the current. The current sense resistor method draws current from the switched power circuit.
Thus there is a need for and it would be advantageous to have a current sensing device and method which does not draw current from the switched power circuit.
BRIEF SUMMARY
According to a feature of the present invention there is provided a device having a switch with a voltage applied across the switch. A current sensing circuit is connected to one terminal of the switch. The current sensing circuit receives power independently of the voltage applied across the switch. The power supply shares the other terminal of the switch with the current sensing circuit. The switch is adapted for opening and closing. When the switch closes, the current sensing circuit senses current through the switch and when said switch is open the high voltage of the switch is blocked from the current sensing circuit. The sense current is preferably caused to flow from the current sensing circuit to the other terminal when the switch is closed. The flow of the sense current produces a voltage which is compared differentially to another voltage referenced by the other terminal. The current sensing circuit may include an operational amplifier which outputs a voltage sense signal which is proportional to the current flowing through the switch. The current sensing circuit may include a switched power converter which includes the switch. The current sensing circuit senses the current while the voltage output of the switched power converter is switched to a common rail. The current sensing circuit draws power independently and not from the switched power converter. The switch is preferably a MOSFET, but may be one of many other switch types—such as, by way of example, insulated-gate bipolar transistor (IGBT), bipolar junction transistor (BJT) or other transistors or similar devices. The switched power converter may be a buck converter or a boost converter or a buck and boost converter. Additionally an inductor is connected to the terminal of the switch and the current sensing circuit senses current through the inductor and does not integrate voltage across the inductor.
According to a feature of the present invention there is provided a method in a device including a switch. A voltage is applied across the switch. A current sensing circuit is connected to one terminal of the switch. The current sensing circuit receives power independently of the voltage. The power derived independently, shares the other terminal of the switch, with the current sensing circuit. The switch is adapted for opening and closing. Upon closing the switch, the current sensing circuit senses the current through the switch. Upon opening the switch, the high voltage of the switch is blocked from the current sensing circuit.
According to a feature of the present invention there is provided a circuit for sensing current flowing through an inductor. The circuit includes: a cathode of a first diode connected to a first side of the inductor. A cathode of a second diode connected to a second side of the inductor. A first node connecting the anode of the first diode with the anode of the second diode. A first voltage divider with a first and second resistor connected between the first node and a power supply. The connection between the first and second resistor forms a second node. A second voltage divider is formed by a third and fourth resistor. A third diode is disposed between the power supply and a ground. The connection between the third and fourth resistor forms a third node. A capacitor is disposed between the ground and the third node. An operational amplifier with a non-inverting input is connected to the second node and an inverting input is connected to the third node. A fifth resistor is connected between the output of the amplifier and the third node. Power is supplied to the operational amplifier and significant current is not drawn from the inductor.
The foregoing and/or other aspects will become apparent from the following detailed description when considered in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
FIG. 1 is a conventional circuit for sensing the output current of a switching regulator.
FIG. 1 a is block diagram of high voltage switch connected to a current sensing circuit according to an embodiment of the present invention.
FIG. 1 b is a circuit diagram of the current sensing circuit with a single input according to an embodiment of the present invention.
FIG. 1 c illustrates a method according to a feature of the present invention.
FIG. 2 is a block diagram of a buck and boost converter connected to a current sensing circuit in an embodiment of the present invention.
FIG. 3 is a block diagram showing circuit details of the buck and boost converter according to an embodiment of the present invention.
FIG. 3 a is graph showing the variation of current in the inductor of a buck and boost circuit according to an embodiment of the present invention.
FIG. 4 is circuit diagram of the current sensing circuit according to an embodiment of the present invention; and
FIG. 5 illustrates a method according to a feature of the present invention.
DETAILED DESCRIPTION
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.
Reference is now made to FIG. 1 a which is block diagram of high voltage switch G X connected to a current sensing circuit 26 a , according to an embodiment of the present invention. High voltage switch G X is connected across a high voltage V X with respect to ground. A current sensing circuit 26 a is connected to the high voltage side (VA) of switch G X . In an embodiment of the present invention, switch G X is a MOSFET. Alternatively switch GX can, in different embodiments of the invention, be a silicon controlled rectifier (SCR), insulated gate bipolar junction transistor (IGBT), bipolar junction transistor (BJT), field effect transistor (FET), junction field effect transistor (JFET), switching diode, mechanically operated single pole double pole switch (SPDT), SPDT electrical relay, SPDT reed relay, SPDT solid state relay, insulated gate field effect transistor (IGFET), DIAC, and TRIAC.
Some embodiments of the present invention are applicable for use in a “switched power converter. The terms “switched power converter” and “switching power converter” are used herein interchangeably and refers to a switching regulator as used for example in a switched-mode power supply (SMPS). While a linear regulator maintains the desired output voltage by dissipating excess power in a pass power transistor, the switched-mode power converter rapidly switches a power transistor between saturation (full on) and cutoff (completely off) with a variable duty cycle whose average is the desired output voltage. The resulting rectangular waveform is typically low-pass filtered with an inductor and capacitor. The “switched power converter” as used herein may perform any type of power conversion or inversion including: alternating current (AC) to direct current (DC) or rectifier operation: DC in to DC out: voltage converter, or current converter, or DC to DC converter; AC in to AC out: frequency changer, cycloconverter, and/or DC in, AC out: inverter.
Reference is now also made to FIG. 1 b which is a circuit diagram of the current sensing circuit 26 a with a single input (VA) according to an embodiment of the present invention. Current sensing circuit 26 a has a power supply VCC 42 which is separate from the high voltage V X across switch G X as shown in FIG. 1 a . Amplifier 40 in an embodiment of the present invention is an operational amplifier (for example OPA2359, Texas Instruments, Dallas, Tex.). It may be noted that other methods for measuring the voltage, such as an Analog to Digital converter (ADC), may also be used. The use of an operational amplifier for this purpose is given here only by way of example. A DC supply V CC 42 and a ground 44 is connected to the power supply inputs of amplifier 40 . A voltage divider chain (VDC) 402 is connected between one end of supply V CC and ground 44 . VDC 402 has a resistor RA 1 with one end connected to supply VCC 42 and the other end connected in series with resistor RB 1 . The other end of resistor RB 1 is connected in series to the anode of diode D 3 . The cathode of diode D 3 is connected to ground 44 . The point in VDC 402 where resistors RA 1 and RB 1 are connected is the non-inverting input to amplifier 40 . A capacitor C is connected in parallel across RB 1 and D 3 and performs function of decoupling the non-inverting input of amplifier 40 and protecting circuit 26 a from high voltages on the ground rail. A second VDC 400 is connected between one end of supply V CC and the connection across inductor 28 shown in FIG. 3 . VDC 400 has a resistor RA 2 with one end connected to supply VCC 42 and the other end connected in series with resistor RB 2 . The other end of resistor RB 2 is connected in to the anode of diode D 1 . The point in VDC 400 connecting resistors RA 2 and RB 2 is attached to the inverting input of amplifier 40 . The cathode of D 1 is connected to the high voltage side of switch G X as shown in FIG. 1 a . A feedback resistor RC is connected between the output of amplifier 40 (V SENSE ) and the inverting input of amplifier 40 . Resistor RC is used to set the gain of amplifier 40 . In an embodiment of the present invention, diodes D 1 and D 3 (for example diode MMSD4148, Fairchild Semiconductor, ME U.S.A.) have a typical maximum repetitive reverse voltage of 100 volts which correspond with the typical voltage values V X found across MOSFET G X . Diodes D 1 and D 3 are also preferably matched diodes.
Referring back to FIG. 1 a when MOSFET G x is closed VA is brought low i.e. near in value to the zero volts of the ground connection of MOSFET G x . Current sensing circuit 26 a senses the current I x which flows through MOSFET G x . With voltage VA low, diode D 1 is forward biased and a measure of the current I x flowing through MOSFET G x is given by Eq.1a when RA 1 =RA 2 =RA and RB 1 =
V SENSE = [ ( V CC · RB + VD 3 · RA RA + RB ) + RC RB ( VD 3 - VD 1 - VA ) ] Eq . 1 a
RB 2 =RB:
where VD 3 is the voltage of diode D 3 . Diode D 3 is used to match the voltage drop of D 1 so that the amplifier 40 won't reach it's saturation point when switch G x is conducting. The current measurement will be accurate when MOSFET G x is conducting. Diode D 1 in current sensing circuit 26 a is in reverse bias when MOSFET G x is off and protects current sensing circuit 26 a from high voltage VA (typically 100 volts).
Reference is now made to FIG. 1 c which illustrates a method according to a feature of the present invention. In decision box 600 , it is determined whether either switch GX is open or closed, if MOSFET G X is open the voltage V X is blocked by current sensing circuit 26 a (step 604 ), if MOSFET G X is closed the voltage V X is sensed by current sensing circuit 26 a (step 602 ) as V SENSE proportional to the current I x flows through MOSFET G X .
Reference is now made to FIG. 2 which illustrates schematically a buck boost converter 24 and current sensing circuit 26 according to an embodiment of the present invention. Buck and boost converter 24 has a buck circuit 20 which receives an input voltage V IN to buck and boost converter 24 . The output voltage of buck circuit 20 VA is with respect to common rail 29 . An inductor 28 and common rail 29 connect the output of buck circuit 20 to the input of boost circuit 22 . The input voltage VB of boost circuit 22 is with respect to common rail 29 . The output of boost circuit 22 is the output voltage V OUT of buck and boost converter 24 . Current sensing circuit 26 is connected across inductor 28 and V SENSE is the output of current sensing circuit 26 .
Reference is now made to FIG. 3 which is a block diagram showing circuit details of buck and boost converter 24 according to an embodiment of the present invention. Buck and boost converter 24 has buck circuit 20 which receives the input voltage V IN to buck and boost converter 24 . Buck circuit 20 has a low side buck MOSFET G A , shunt connected across the output of buck circuit 20 and a high side buck MOSFET G C , connected in series between the output and input of buck circuit 20 . A capacitor C 1 is shunt connected across the input of buck circuit 20 . The output voltage of buck circuit 20 VA is with respect to common rail 29 . Inductor 28 and common rail 29 connects the output of buck circuit 20 to the input of boost circuit 22 . Boost circuit 22 has a low side boost MOSFET G B , shunt connected across the input of boost circuit 22 and a high side boost MOSFET G D , connected in series between the output and input of boost circuit 22 . A capacitor C 2 is shunt connected across the output of boost circuit 22 . Current sensing circuit 26 is connected across inductor 28 and V SENSE is the output of current sensing circuit 26 .
Reference is now also made to FIG. 3 a , a graph showing the variation of current IL in inductor 28 according to an embodiment of the present invention. The working operation of buck and boost converter 24 is in two time phases T 1 and T 2 . Referring back to FIG. 3 , in time phase T 2 buck and boost converter 24 operates with MOSFETS G A off, G B on, G D off and G C on. During phase T 1 the output voltage of buck circuit 20 VA is approximately the input voltage V IN of buck and boost converter 24 and the input voltage of boost circuit 22 VB is brought low i.e. near in value to the zero volts of common rail 29 . In time phase T 1 , buck and boost converter 24 operates with MOSFETS G A on, G B off, G D on and G C off. During phase T 2 the output voltage of buck circuit 20 VA is brought low i.e. near in value to the zero volts of common rail 29 and the input voltage of boost circuit 22 VB is initially approximately equal to the output voltage V OUT of buck and boost converter 24 . During phase T 1 , current sensing circuit 26 is sensing the current I S which flows through MOSFET G A .
Reference is now also made to FIG. 4 . which is a circuit diagram of current sensing circuit 26 according to an embodiment of the present invention. Amplifier 40 in an embodiment of the present invention is an operational amplifier (for example OPA2359, Texas Instruments, Dallas, Tex.). It may be noted that other methods for measuring the voltage, such as an Analog to Digital converter (ADC), may also be used. The use of an Op-Amp for this purpose is given here only by way of example. A DC supply V CC 42 and a ground 44 is connected to the power supply inputs of amplifier 40 . A voltage divider chain (VDC) 402 is connected between one end of supply V CC and ground 44 . VDC 402 has a resistor RA 1 with one end connected to supply VCC 42 and the other end connected in series with resistor RB 1 . The other end of resistor RB 1 is connected in series to the anode of diode D 3 . The cathode of diode D 3 is connected to ground 44 . The point in VDC 402 where resistors RA 1 and RB 1 are connected is the non-inverting input to amplifier 40 . A capacitor C is connected in parallel across RB 1 and D 3 and performs function of decoupling the non-inverting input of amplifier 40 . A second VDC 400 is connected between one end of supply V CC and the connection across inductor 28 shown in FIG. 3 . VDC 400 has a resistor RA 2 with one end connected to supply VCC 42 and the other end connected in series with resistor RB 2 . The other end of resistor RB 2 is connected in to the anodes of diodes D 1 and D 2 . The point in VDC 400 connecting resistors RA 2 and RB 2 is attached to the inverting input of amplifier 40 . The cathodes of D 1 and D 2 are connected across inductor 28 as shown in FIG. 3 . A feedback resistor RC is connected between the output of amplifier 40 (V SENSE ) and the inverting input of amplifier 40 . Resistor RC is used to set the gain of amplifier 40 . In an embodiment of the present invention, diodes D 1 , D 2 and D 3 (for example diode MMSD4148, Fairchild Semiconductor, ME U.S.A.) have a typical maximum repetitive reverse voltage of 100 volts which correspond with typical voltages VA and VB found in buck and boost converter 24 .
Referring back to FIG. 3 a , during phase T 1 the output voltage of buck circuit 20 VA is brought low i.e. near in value to the zero volts of common rail 29 , and the input voltage of boost circuit 22 VB is initially approximately equal to the output voltage V OUT of buck and boost converter 24 . During phase T 1 , current sensing circuit 26 senses the current I S which flows through MOSFET G A . Diode D 2 in current sensing circuit 26 is in reverse bias and protects current sensing circuit 26 from high voltage VB which is typically 100 volts. During phase T 1 with voltage VA low, diode D 1 is forward biased and a measure of the current I S flowing through MOSFET G A is given by Eq.1 when RA 1 =RA 2 =RA and RB 1 =RB 2 =RB:
V SENSE = [ ( V CC RB RA + RB ) + VD 3 - ( I S Rds ) RC RB ] Eq . 1
where Rds is the resistance between drain and source of MOSFET G A and VD 3 is the voltage of diode D 3 . Diode D 3 is used to match the voltage drop across D 1 so that the current measurement will be accurate when MOSFET G A is conducting. During phase T 2 , current sensing circuit 26 is sensing the current I S which flows through MOSFET G B . Diode D 1 in current sensing circuit 26 is in reverse bias and is protecting current sensing circuit 26 from high voltage VA which is typically 100 volts. During phase T 2 with voltage VB low, diode D 2 is forward biased and a measure of the current I S flowing through MOSFET G B is given by Eq.2 when RA 1 =RA 2 =RA and RB 1 =RB 2 =RB.
V SENSE = [ ( V CC RB RA + RB ) + VD 3 + ( I S Rds ) RC RB ] Eq . 2
where Rds is the resistance between drain and source of MOSFET G B and VD 3 is the voltage of diode D 3 . Diode D 3 is used to match the voltage drop across D 2 so that the current measurement will be accurate when MOSFET G B is conducting.
Reference is now made to FIG. 5 which illustrates a method according to a feature of the present invention. In decision box 500 , it is determined whether either of high voltages VA or VB are low (i.e. switched to common rail 29 ) and if so, the voltage differential between VA and VB is sensed (step 502 ) as V SENSE proportional to the current Is flowing through MOSFETS G A or G B .
The articles “a”, “an”, as used hereinafter are intended to mean and be equivalent to “one or more” or “at least one”, For instance, “a switch-e” means “one or more switches”.
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. | A device having a switch with a voltage applied across the switch. A current sensing circuit is connected to one terminal of the switch. The current sensing circuit receives power independently of the voltage applied across the switch. The power supply shares the other terminal of the switch with the current sensing circuit. The switch is adapted for opening and closing. When the switch closes, the current sensing circuit senses current through the switch and upon opening the switch the high voltage of the switch is blocked from the current sensing circuit. The sense current is caused to flow from the current sensing circuit to the other terminal when the switch is closed. The flow of the sense current produces a voltage which is compared differentially to another voltage referenced by the other terminal. |
ORIGIN OF THE INVENTION
The invention described herein was made in the course of or under a grant from the National Science Foundation, an Agency of the United States Government.
BACKGROUND OF THE INVENTION
1. Field of the Invention:
This invention relates generally to liquid chromatography, and more particularly to a flame aerosol detector and a method for using the same.
2. Description of the Prior Art:
A variety of detector systems for use in liquid chromatography are known at the present time. These presently known devices have sought, through reliance upon different sensing techniques, to achieve the illusive goal of providing a detector that is both universal and extremely sensitive.
A brief summary of such previously known devices is presented in co-pending application, Ser. No. 483,297, filed June 26, 1974. This same application describes a novel liquid chromatography detector and a novel method of detection for sensing solutes through a spray impact technique. Although the method and apparatus described in this co-pending application have proven to be extremely sensitive, the sensitivity is greatest for such compounds as fatty acids, phenols, detergents of the alkylsulfonate type, amino acids, amines, inorganic acids, bases, and salts. The spray impact detector is somewhat less sensitive to nonionic organic compounds, particularly those of low molecular weight.
A need therefore exists for a detector of substantially universal application combined with high sensitivity.
SUMMARY OF THE INVENTION
Accordingly, it is one object of this invention to provide a novel method of detecting solutes in liquid chromatography.
Another object of the present invention is the provision of a novel apparatus for detecting solutes in liquid chromatography.
A still further object of the present invention is the provision of a novel flame aerosol detector for liquid chromatography.
A still further object of the present invention is the provision of a novel flame aerosol detector including an apparatus for removing unwanted ionic species from a charged aerosol spray.
Yet another object of the present invention is the provision of a novel method of detecting solutes in liquid chromatography including the step of removing undesired ionic species from a charged aerosol spray.
Briefly, these and other objects of the invention are achieved by providing a detector including a burner flame into which the eluent of a liquid chromatography system is aspirated. A filter electrode is placed above the burner flame for removing unwanted gas phase ionic species from the rising particle stream emerging from the flame. An evacuated detection chamber, having a small aperture positioned above the flame, is provided for collecting charged aerosol particles passing the filter electrode. A pair of electrodes positioned within the chamber is coupled to an electronic network for sensing the current flow in the chamber which varies as solutes reach the detection chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG. 1 is a schematic diagram of a liquid chromatography system having the detector of the present invention attached thereto;
FIG. 2 is a partially cut-away illustration of the detector structure of the present invention showing more clearly the structural details thereof;
FIG. 3 is a block diagram of the electrical system of the present invention;
FIG. 4A is a graph illustrating the output of the detector of the present invention with no potential applied to the filter electrode;
FIG. 4B is a graph illustrating the output of the detector of the present invention with a potential of 400 volts with respect to ground applied to the filter electrode;
FIG. 5 is a graph at high recorder chart speed illustrating the output of the detector of the present invention with various positive potentials applied to the filter electrode;
FIG. 6 is a graph at high recorder chart speed illustrating the output of the detector of the present invention with various negative potentials applied to the filter electrode and,
FIG. 7 is an illustration of a concentric arrangement for the fuel, air and effluent tubes.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof, a liquid chromatograph system is shown illustrating the environment of the present invention. The illustrated liquid chromatograph system includes a mobile phase reservoir 10 coupled to a pump 12 having a pulse dampening column 14 connected to the output thereof. A pressure gauge 16 is coupled between the output of pump 12 and an injection valve 18, which is in turn connected to a sample inlet 20 at the top of liquid chromatographic column 22. It is noted that samples may be introduced either by injection of microliter amounts by syringe at the sample inlet 20 or by using a sample loop containing dilute solution at the injection valve 18. Thus either the injection valve or the sample inlet may be omitted from the system if desired. The base of the chromatographic column 22 may be coupled to a splitter valve 24 which divides the column output between a sample collection vessel or waster container 26 and the detector 28 constructed in accordance with the teachings of the present invention.
The illustrated chromatography system is conventional and may be of the type described in U.S. Bureau of Standards Technological Note No. 589. Page 1 (July 1970 to June 1971) by D. H. Freeman and W. L. Zielinski modified to include a lengthened pulse dampening column so that the system is virtually pulse free at high pressures. Naturally it will be understood by those skilled in the art that the detector of the present invention is not limited to use with the particular type of liquid chromatograph system shown, and can be used with virtually any commercially available system.
Attention is now directed to FIG. 2 wherein the flame aerosol detector of the present invention is shown in greater detail as including a conventional burner 30 for producing a charged aerosol spray in the flame as described below. The burner includes a barrel portion 32 having three inlet tubes connected to its base portion. These include a fuel inlet 34 connected to a supply 36 of suitable burner fuel, such as hydrogen, an air inlet 38 connected to a suitable supply of pressurized air or oxygen 40 and a column effluent inlet 42, connected to the output of the chromatograph column 22 illustrated in FIG. 1.
In practice the inlets 34, 38 and 42 may be formed of stainless steel tubes arranged in a concentric configuration with the mobile phase inlet at the center surrounded by the air inlet so that the high velocity incoming air flow both aspirates the liquid chromatograph output into the burner and divides it into fine aerosol particles. The fuel inlet preferably surrounds the air inlet. The air or oxygen inlet tube 38 may have an inner diameter of approximately 0.08 cm., the fuel inlet 34 an inner diameter of approximately 0.20 cm. and the mobile phase inlet 42 an inner diameter of approximately 0.04 cm. and an outer diameter of approximately 0.07 cm.
The aerosol formed as described above is propelled into the flame 43 resulting from combustion of the mentioned fuel-air mixture, where a portion of the aerosol particles desolvate and solute, if present, burns and is ionized. Larger droplets pass through the flame without complete desolvation.
A filter electrode 44 for removing desolvated ionic species is mounted above the flame 43 directly in the path of the rising aerosol stream. The filter electrode may be formed of either a loop of inert metal, such as platinum wire, a screen of inert metal or a section of 20-mesh copper screen, although other electrode materials, mesh size, and configurations may also be used.
A detection chamber 45 is positioned above the filter electrode 44 and includes an aerosol inlet assembly 46 positioned directly above flame 43. The detection chamber may, for example, be formed of a copper cylinder of approximately 2 inches inner diameter, although other structures may also be used. The aerosol inlet assembly 46 may include a length of 1/8 inch stainless steel tubing having an inner diameter of approximately 0.2 cm. and extending approximately 0.8 cm. into the chamber 45 for limiting the size of particles admitted to the detection chamber. The tube 48 is connected to a component 50 having an enlarged opening for funneling aerosol particles emerging from flame into the chamber 45. The component 50 may, for example, be a standard Swagelok reduction union joined to the tube 48, although other types of equivalent fittings can also be used. A heat shield 52, which may be constructed of asbestos, is positioned below the detection chamber to insulate it from the heat of the burner flame.
A vacuum union 54 is mounted in the peripheral wall of the detection chamber for coupling the interior of the chamber with a conventional vacuum system 55, such as a pump or water aspirator, for example. The top of the detection chamber is sealed with a copper disc 56 in which two electrical connectors 58 and 60 are mounted by means of a pair of insulating plugs 62 and 64, respectively, formed of Teflon (TM) or the like. The electrical connectors 58 and 60 are coupled by means of a pair of conductive leads 66 to a pair of detector electrodes 68A and 68B positioned within the detection chamber and spaced approximately 1 inch apart. Other spacings may also prove useful, as will be apparent to those skilled in the art. The detector electrodes may, for example, be formed of 1/2 inch wide by 1 inch long panels of palladium-silver alloy or other conducting material.
The varying current flowing between the electrodes 68A and 68B is sensed and recorded by the electrical network illustrated in FIG. 3 for providing a suitable output from the detector 28. The electrical network illustrated in FIG. 3 includes a conventional constant voltage transformer 70 adapted to be plugged into a normal 110 volt AC wall outlet. A variable voltage regulated power supply 72, which may be a Heath Model PS-3 for example, receives its input power from the constant voltage transformer and is coupled at its output to electrical connector 60 for supplying an input potential to the detector electrode 68B in the detection chamber. While input potentials between 150 and 700 volts with respect to ground provide a suitable output response with the geometry described, the detector electrode is preferably maintained at a constant 400 volts with respect to ground for optimum detector response. A lead 74 is provided for grounding the variable voltage supply 72 through the detection chamber ground 80.
Detector electrode 68A and electrical connector 58 are coupled by coaxial cable 76 to a conventional electrometer 78, such as a Keithley Model 603. The electrometer and the detection chamber are also coupled to a suitable reference potential, such as ground, as illustrated at 80. The electrometer output is applied to a conventional chart recorder 82, a Sargent Model MR recorder, for example, in order to continuously record the output of the electrometer. A suitable voltage source 84 is coupled to the filter electrode 44 for supplying a filtering potential thereto. The voltage source 84 may be a commercially available source, such as a Heath Model MP-5 power supply, or it may be a constant voltage source for supplying a fixed voltage such as ± 100v with respect to ground.
The filter electrode is an important feature of the present invention in that it substantially increases the sensitivity of the detector and improves peak shape as shown in FIGS. 4A and 4B illustrating detector response as a function of time with and without an applied filter electrode potential. More specifically, FIG. 4A illustrates that with no applied filter electrode potential, the detector upon sensing a solute may generate an output signal having a split positive peak 86 and 88 separated by a substantial negative peak 90. The resultant output signal is thus ambiguous and has a lower signal-to-noise ratio than that in FIG. 4B. FIG. 4B illustrates the detector output current when a positive potential of 400 volts with respect to ground is applied to the filter electrode. FIG. 4B shows a single major positive peak 92 providing a clear, unambiguous output signal with a signal-to-noise ratio that is substantially greater than in the example illustrated of FIG. 4A. TABLE 1 below sets forth the experimental parameters relating to FIGS. 4A and 4B.
TABLE 1__________________________________________________________________________FIGS. 4A and 4B__________________________________________________________________________Electrometer setting: 250mV full scaleRecorder: 5 volts full scalePotential applied to electrode68B in detector chamber +400 volts with respect to groundSample: 0.5ml containing 1.56 mg/ml. n-propanolFuel flow: approximately 2500 ml/min. (hydrogen)Air flow: approximately 5800 ml/min.Liquid flow: about 3 ml/min.Pressure in chamber 690 torr (water aspirator)Chart speed: 3 min/in.__________________________________________________________________________
The effectiveness of the filter electrode is a function of the applied filter potential, as illustrated in FIGS. 5 and 6 and in TABLE 2 below.
TABLE 2__________________________________________________________________________FIGS. 5 and 6__________________________________________________________________________Potential applied to electrode68B in detection chamber: +400 volts with respect to groundSample: 0.5 ml. containing 1.56 mg/ml. n-propanolChart speed: high speed--30 sec/in.Pressure in detector chamber 695 torr (water aspirator) FIG. 5 FIG. 6__________________________________________________________________________Filter electrode potential: Filter electrode potential: (with respect to ground) (with respect to ground) Peak A: + 100 volts Peak B: + 200 volts Peak C: + 400 volts Peak D: + 30 volts Peak A: - 100 volts Peak E: + 20 volts Peak B: - 25 volts Peak F: + 10 volts Peak C: - 5 volts Peak G: 0 volts Peak D: volts__________________________________________________________________________
FIG. 5 illustrates that an M-shaped peak G occurs when no voltage is applied to the filter electrode, and that the inverted peak diminishes rapidly as the applied voltage is increased to +100 volts with respect to ground, with a slight decrease in positive signal at higher potentials. Similarly, FIG. 6 indicates substantially the same effect with a negative voltage applied to the filter electrode. The two figures illustrate that the approximate optimum filter electrode potentials are ± 100 volts under the operation conditions listed above.
AC potentials of varying magnitudes and frequencies may also be applied to the filter electrode. Experimental results show that the application of a 60 cycle, ± 6.3 volt AC signal to the filter electrode results in filtering qualities similar to those found with a DC source of several hundred volts coupled to the filter electrode. The detection peak with this AC signal was also of substantially the same area as with the DC signals, although noise levels were slightly higher than with the DC filtering potential. Low frequency square waves of ± 180 volts at 7.5 and 11 Hz were applied to the filter electrode and also showed the filtering qualities of equivalent DC potentials. AC signals of ± 10 volts at frequencies from 100 Hz to 10kHz were also used, and the results were found to be similar to equivalent DC potentials. A ± 60 volt square wave up to 1MHz was also tried. It was found that frequencies up to about 2500 Hz provided good filtering characteristics. Frequencies above this value generally produced some loss of peak area and the M-shaped inverted peak illustrated in FIG. 4A reappeared although some filteration was present since the inverted peak was reduced to about half of its no signal level.
Although adjustments in the filter electrode potential have a pronounced effect on the response of the detector of the present invention, the operating parameters of the detection chamber 45 and the vacuum system 55 also influence output response.
The temperature of the detection chamber has an effect on the sensitivity of the detector, for example. The detection chamber is insulated from the burner flame by a board of asbestos, or an equivalent material, as pointed out above, in order to prevent the temperature of the detection chamber from exceeding the melting point of the Teflon plugs 62 and 64. The response of the detector has been found to increase with detection chamber temperature, reaching a maximum when the chamber reaches its stable equilibrium temperature.
Electrode spacing within the detection chamber affects the response of the system, and may be varied from the one inch spacing mentioned above, although a spacing of one inch appears to provide an optimum response with a relatively low noise level and a relatively high output stability with the detector geometry illustrated in FIG. 2.
Similarly, the vacuum maintained within the detection chamber affects the response of the system. Little current flows in the detector chamber without some reduction in pressure; the amount of current flow increasing as the chamber pressure is reduced, although noise also increases with reduced pressure. A water aspirator maintaining the chamber pressure between 690 and 700 torr produced suitable performance. Mechanical pump vacuum systems can be used to further reduce the detection chamber pressure.
Having described the apparatus of the present invention, its method of operation will now be described in greater detail.
It is initially assumed that the fuel and air supplies to the burner 30 are operating, that the burner is lit and that the electrical and chromatograph systems are functioning in their normal, stable state. A sample to be analyzed is then injected into the sample inlet 20 for passage through the liquid chromatograph column 22. The eluent emerging from the base of the column is divided by the splitter valve 24 with a selected fraction of the eluent being delivered to the sample collection vessel 26 and the remaining fraction being supplied to the burner 30.
The eluent delivered to the burner is aspirated into the flame by the high velocity air stream supplied to the burner. Aspiration of the eluent liquid causes it to be broken into small droplets, forming an aerosol within the flame. When the aerosol is formed of an organic compound mixed in a mobile phase such as water, the flame burning the aerosol produces ions by the chemi-ionization process. This causes a sudden increase in ion concentration within each aerosol droplet as well as an increase in evaporation and reduction in surface tension along the liquid-gas interface. As a result the aerosol particles tend to explode into a shower of smaller particles which, along with completely desolvated ionic species, move toward the filter electrode.
The filter electrode removes the highly mobile, desolvated ionic species from the stream of undesolvated, charged droplets passing through the flame and thus prevents these gas phase ions from entering the detection chamber. Removal of these gaseous ions from the particle stream is believed to be responsible for the elimination of the negative peak 90 shown in FIG. 4A. The charged droplets remaining in the particle stream are largely unaffected by the filter electrode potential owing to their relatively large mass and momentum.
Charged droplets passing the filter electrode enter the enlarged inlet component 50 and proceed upward into the detection chamber 45 under the influence of their initial momentum as well as under the influence of the reduced pressure within the chamber. Some of the charged droplets collide with the walls of the inlet tube and are grounded, while remaining droplets of appropriate dimensions travel the distance of the inlet tube and reach the region of the electrodes 68A and 68B. Thus the inlet tube sorts the droplets to some extent, and passes only those aerosol particles with dimensions within the limited range.
When droplets enter into the detection chamber they have attained a relatively high velocity and at the same time are subjected to the hot, reduced pressure environment of the chamber as well as to the force field of the electrodes. These forces, combined with the force of gravity which normally acts on them, cause the aerosol particles within the chamber to become an extremely finely divided charged mist. This fine charged mist causes the current flow between the electrodes which fluctuates in response to the presence of the desolved solutes injected into the chromatograph system. Other mechanisms, yet not fully understood, may also provide or contribute to the change in signal observed as the solutes are eluted.
When an organic compound is eluted, increased evaporation, instability of the droplet, and several other processes cause a much smaller initial droplet. This brings about a significant decrease in the number of particles reaching the chamber with a decrease in the amount of charged mist and current flow. The varying current is detected by the electrical system of the present invention, whereby output peaks are produced as solute components reach the detector electrodes.
Tests with n-propanol show that a plot of log (peak area) vs. log concentration is linear over at least five orders of magnitude while other commercial detectors are rarely linear more than 3-4 orders of magnitude. The lower limit of detection for n-propanol was found to be 64 ng/ml (64 parts per billion), far exceeding the limit of detection of n-propanol with other detectors presently commercially available. Furthermore the detector of the present invention was found to produce an increasing response with an increase in carbon number so that even lower detection limits are found for compounds of higher molecular weight. Among the other compounds studied and found to give high sensitivity are dimethyl sulfoxide, sulfanilic acid, p-toluidine, benzene, resorcinol, benzyl disulfide, caffeine, thioacetamide, benzyl alcohol, 1,4-butanediol, alanine, aspartic acid, ethyl butyrate, potassium chloride, and an homologous series of alchols from methyl alcohol to heptyl alcohol. All compounds tested give a signal upon elution, and it is believed that the flame aerosol detector is truly a universal detector.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. | A sensitive universal detector for liquid chromatography is disclosed in which eluent from a liquid chromatograph column is aspirated into a flame and broken into a fine spray of aerosol particles. Water, when used as the mobile phase, is not ionized appreciably by the flame but does form charged droplets by rupturing of the liquid surface. The solute, when desolvated and burned in the flame, forms ionized species which affect the amount of charge on the aerosol particles. The aerosol particles, partially desolvated and ionized by the burner flame, move upward toward a filter electrode which removes gas phase ionic species from the particle stream. The charged, undesolvated aerosol particles passing the filter electrode enter an evacuated detection chamber in which a pair of detector electrodes is positioned. An electrometer system senses a varying current between the detector electrodes as each solute is eluted from the column. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No. 10/158,979, filed May 30, 2002, pending, which is a continuation of application Ser. No. 09/876,805, filed Jun. 7, 2001, now U.S. Pat. No. 6,478,627, issued Nov. 12, 2002, which is a continuation of application Ser. No. 09/487,935, filed Jan. 20, 2000, now U.S. Pat. No. 6,319,065 B1, issued Nov. 20, 2001, which is a continuation of application Ser. No. 09/072,260, filed May 4, 1998, now U.S. Pat. No. 6,089,920, issued Jul. 18, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to methods and apparatus for electrically connecting semiconductor devices to circuit boards. More particularly, the invention relates to a socket into which one or more bare semiconductor die may be inserted for connection to a circuit board without wire bonding of the contact pads of the semiconductor die.
[0004] 2. State of the Art
[0005] The assembly of a semiconductor device from a leadframe and semiconductor die ordinarily includes bonding of the die to a paddle of the leadframe, and wire bonding bond pads on the die to inner leads i.e. lead fingers of the leadframe. The inner leads, semiconductor die, and bond wires are then encapsulated, and extraneous parts of the leadframe excised, forming outer leads for connection to a substrate such as a printed wiring board (PWB).
[0006] The interconnection of such packaged integrated circuits (IC) with circuit board traces has advanced from simple soldering of package leads to the use of mechanical sockets, also variably known as connectors, couplers, receptacles and carriers. The use of sockets was spurred by the desire for a way to easily connect and disconnect a packaged semiconductor die from a test circuit, leading to zero-insertion-force (ZIF), and low-insertion-force (LIF) apparatus. Examples of such are found in U.S. Pat. No. 5,208,529 of Tsurishima et al., U.S. Pat. No. 4,381,130 of Sprenkle, U.S. Pat. No. 4,397,512 of Barraire et al., U.S. Pat. No. 4,889,499 of Sochor, U.S. Pat. No. 5,244,403 of Smith et al., U.S. Pat. No. 4,266,840 of Seidler, U.S. Pat. No. 3,573,617 of Randolph, U.S. Pat. No. 4,527,850 of Carter, U.S. Pat. No. 5,358,421 of Petersen, U.S. Pat. No. 5,466,169 of Lai, U.S. Pat. No. 5,489,854 of Buck et al., U.S. Pat. No. 5,609,489 of Bickford et al., U.S. Pat. No. 5,266,833 of Capps, U.S. Pat. No. 4,995,825 of Korsunsky et al., U.S. Pat. Nos. 4,710,134 and 5,209,675 of Korsunsky, U.S. Pat. No. 5,020,998 of Ikeya et al., U.S. Pat. No. 5,628,635 of Ikeya, U.S. Pat. No. 4,314,736 of Demnianiuk, U.S. Pat. No. 4,391,408 of Hanlon et al., and U.S. Pat. No. 4,461,525 of Griffin.
[0007] New technology has enabled the manufacture of very small high-speed semiconductor dice having large numbers of closely spaced bond pads. However, wire bonding of such semiconductor dice is difficult on a production scale. In addition, the very fine wires are relatively lengthy and have a very fine pitch, leading to electronic noise.
[0008] In order to meet space demands, much effort has been expended in developing apparatus for stack-mounting of packaged dies on a substrate in either a horizontal or vertical configuration. For. example, vertically oriented semiconductor packages having leads directly connected to circuit board traces are shown in U.S. Pat. No. 5,444,304 of Hara et al., U.S. Pat. No. 5,450,289 of Kweon et al., U.S. Pat. No. 5,451,815 of Taniguchi et al., U.S. Pat. No. 5,592,019 of Ueda et al., U.S. Pat. No. 5,619,067 of Sua et al., U.S. Pat. No. 5,635,760 of Ishikawa, U.S. Pat. No. 5,644,161 of Burns, U.S. Pat. No. 5,668,409 of Gaul, and United States Reissue Patent Re. 34,794 of Farnworth.
[0009] However, none of the above patents relates to the socket interconnection of a bare i.e. unpackaged semiconductor die to a substrate such as a circuit board.
[0010] Sockets also exist for connecting daughter circuit boards to a mother board, as shown in U.S. Pat. No. 5,256,078 of Lwee et al. and U.S. Pat. No. 4,781,612 of Thrush. U.S. Pat. No. 4,501,461 and Re. 28,171 of Anhalt show connectors for connecting a socket to a circuit board, and wiring to an electronic apparatus, respectively.
[0011] U.S. Pat. No. 5,593,927 of Farnworth et al. discloses a semiconductor die having an added protective layer and traces, and which is insertable into a multi-die socket. The conductive edges of the semiconductor die are connected through an edge “connector” to circuit board traces. The number of insertable semiconductor dice is limited by the number of semiconductor die compartments in the socket, and using fewer dice is a waste of space.
BRIEF SUMMARY OF THE INVENTION
[0012] A modular bare die socket is provided by which any number of bare (unpackaged) semiconductor dice having bond pads along the edge of one major side may be interconnected with a substrate in a densely packed arrangement. The socket is particularly applicable to high speed, e.g. 300 MHZ dice of small size or those dice of even faster speeds.
[0013] The socket comprises a plurality of plates which have a semiconductor die slot structure for aligning and holding a bare die or dice in a vertical orientation, and interconnect structure for aligning and retaining a multi-layer lead tape in contact with conductive bond pads of an inserted die. The interconnect lead tapes have outer ends which are joined to conductive traces on a substrate such as a printed wiring board (PWB).
[0014] Each lead tape includes a node portion which is forced against a bond pad to make resilient contact therewith. Various means for providing the contact force include a resilient lead tape, an elastomeric layer or member biasing the lead tape, or a noded arm of the plate, to which the lead tape is fixed.
[0015] A multi-layer interconnect lead tape may be formed from a single layer of polymeric film upon which a pattern of fine pitch electrically conductive leads is formed. Methods known in the art for forming lead frames, including negative or positive photoresist optical lithography, may be used to form the lead tape. The lead tape may be shaped under pressure to the desired configuration.
[0016] The plates with intervening interconnect lead tapes are bonded together with adhesive or other means to form a permanent structure.
[0017] The plates are formed of an electrically insulative material and may be identical. Each plate has “left side structure” and “right side structure” which work together with the opposing structure of adjacent plates to achieve the desired alignment and retaining of the semiconductor die and the lead tape for effective interconnection.
[0018] Any number of plates may be joined to accommodate the desired number of bare semiconductor dice. Assembly is easily and quickly accomplished. If desired, end plates having structure on only one side may be used to cap the ends of the socket.
[0019] Thus, a socket is formed as a dense stack of semiconductor die-retaining plates by which the footprint per semiconductor die is much reduced.
[0020] The modular socket is low in cost and effectively provides the desired interconnection. A short interconnect lead distance is achieved, leading to reduced noise. The impedance may be matched up to the contact or semiconductor die.
[0021] The primary use of the modular bare semiconductor die socket is intended to be for permanent attachment to circuit boards of electronic equipment where die replacement will rarely be required. Although the socket may be used in a test stand for temporarily connecting dice during testing, new testing techniques performed at the wafer scale generally obviate the necessity for such later tests.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0022] The invention is illustrated in the following figures, wherein the elements are not necessarily shown to scale:
[0023] [0023]FIG. 1 is a perspective view of a modular socket of the invention;
[0024] [0024]FIG. 2 is a perspective view of partially assembled modules of a modular socket of the invention;
[0025] [0025]FIG. 3 is a cross-sectional edge view of a portion of a modular socket of the invention, as generally taken along line 3 - 3 of FIG. 1 and having an exploded portion;
[0026] [0026]FIG. 4 is a perspective view of a multi-layer lead tape useful in a modular bare die socket of the invention;
[0027] [0027]FIG. 5 is a plan view of a multi-layer lead tape useful in a modular bare die socket of the invention;
[0028] [0028]FIG. 5A is a plan view of another embodiment of a multi-layer lead tape of a modular bare die socket of the invention;
[0029] [0029]FIG. 6 is a perspective view of a further embodiment of a multi-layer lead tape of a modular bare semiconductor die socket of the invention;
[0030] [0030]FIG. 7 is a perspective view of partially assembled modules of a further embodiment of a modular bare semiconductor die socket of the invention;
[0031] [0031]FIG. 8 is a perspective view of partially assembled modules of an additional embodiment of a modular bare semiconductor die socket of the invention;
[0032] [0032]FIG. 9 is a cross-sectional edge view of a portion of a further embodiment of a modular bare semiconductor die socket of the invention, as taken along line 3 - 3 of FIG. 1, and having an exploded portion;
[0033] [0033]FIG. 10 is a cross-sectional edge view of a portion of another embodiment of a modular bare semiconductor die socket of the invention, as taken along line 3 - 3 of FIG. 1;
[0034] [0034]FIG. 11 is a view of a semiconductor die for use in the modular bare semiconductor die socket of FIG. 10;
[0035] [0035]FIG. 12 is a view of the semiconductor die of FIG. 11 used in the modular bare semiconductor die socket of FIG. 10; and
[0036] [0036]FIG. 13 is a view of an alternative embodiment of the semiconductor die and modular bare semiconductor die socket of FIG. 12 illustrating a modified lead tape.
DETAILED DESCRIPTION OF THE INVENTION
[0037] As depicted in drawing FIG. 1, a modular bare die socket 10 of the invention comprises a plurality of modules 12 A, 12 B and 12 C formed of plates 14 A, 14 B, 14 C, and 14 D which are stacked perpendicular to a substrate 16 . A bare (unpackaged) semiconductor die 18 with conductive bond pads (not visible) near one edge on a major surface 20 thereof, e.g. the “active surface” may be inserted as shown into a die slot 22 and have its bond pads interconnected to conductive traces (not visible) on the surface 24 of the substrate 16 .
[0038] The internal structures of plates 14 C and 14 D are depicted in drawing FIG. 2. Each of the plates 14 A, 14 B, 14 C and 14 D has a first side 26 and an opposing second side 28 . The plates have first ends 30 having die slots 22 , and second ends 32 having lead slots 44 through which lead tapes pass.
[0039] In these figures, the first side 26 is taken as the left side of each plate and the second side 28 is taken as the right side. The regular plates 14 A, 14 B and 14 C have structure on both sides 26 , 28 and may be the exclusive plates of the socket 10 . The structure provides for accommodating bare semiconductor dice 18 of a particular size, number and spacing of bond pads, etc. and for electrically interconnecting the semiconductor dice 18 to a substrate 16 . Typically, all regular plates 14 A, 14 B, 14 C of a bare die socket 10 are identical but in some cases may differ to accommodate semiconductor dice of different size, bond pad configuration, etc. within different modules 12 A, 12 B, 12 C, etc. of a socket.
[0040] Alternatively, one or two end plates 14 D may be used to cap any number of intervening regular plates 14 A, 14 B and 14 C. In contrast to the regular plates 14 A, 14 B and 14 C, such end plates 14 D have cooperating structure on one side only, i.e. the internal side, and may simply have a flat exterior side which in drawing FIGS. 1, 2 and 3 is the second side 28 . Specifically designed end plates 14 D may be used on either, neither or both ends of the socket 10 , and have structure on one side to complement the facing side of the adjacent regular plate 14 A, 14 B, 14 C.
[0041] The structure of the second side 28 of the regular plates 14 A, 14 B and 14 C is shown as including an upwardly opening die slot 22 with a side wall 34 , edge walls 38 , and stop end wall 36 of lower beam 40 . Lower beam 40 has an exposed surface 42 which is one side of an interconnect lead slot 44 . The lower beam 40 is shown as having a width 41 exceeding width 46 for accommodating means for accurate alignment and retention of a multi-layer interconnect lead tape 50 , not shown in drawing FIG. 2 but to be described later in relation to drawing FIGS. 3 through 6.
[0042] The first sides 26 of plates 14 A, 14 B, 14 C and 14 D are as shown with respect to end plate 14 D. In this embodiment, first side 26 is largely flat with a recess 48 for accommodating portions of the interconnect lead tape. Recess 48 has a width 60 which is shown to approximate the width 46 of the die slot 22 , and has a depth 62 which is sufficient to take up the lead tape 50 when it is compliantly moved into the recess upon insertion of a semiconductor die 18 into die slot 22 .
[0043] The module 12 C including the first side of plate 14 D and the second side of plate 14 C has alignment posts 52 and matching holes 54 for alignment of the plates 14 C, 14 D to each other. Also shown are alignment/retention posts 56 and matching holes 58 for (a) aligning and retaining an interconnect lead tape 50 in the module, and for (b) aligning the plates 14 C, 14 D with each other. The posts 52 , 56 and matching holes 54 , 58 together comprise a module alignment system.
[0044] Mating portions of adjacent plates are joined by adhesive following installation of the lead tape 50 on alignment/retention posts 56 . Each of the posts 52 , 56 is inserted into holes 54 , 58 so that all of the plates 14 A, 14 B, 14 C and 14 D are precisely aligned with each other to form a monolithic socket 10 . In drawing FIG. 3, all of the regular plates 14 A, 14 B, and 14 C are identical.
[0045] In the views of drawing FIGS. 3 through 5, a multi-layer interconnect lead tape 50 is shown as comprised of a first insulative layer 64 , with a second layer 66 of conductive leads 70 fixed to it. The insulative layer 64 may be formed of a film of polymeric material such as polyimide, polyimide siloxane, or polyester. A conductive layer 66 , typically of metal, is formed on the insulative layer 64 in the form of individual leads 70 A, 70 B, 70 C, etc. Methods well-known in the industry for producing multi-layer lead frames may be used for forming the fine pitch leads 70 on the insulative layer 64 . Thus, for example, the leads 70 may be formed by combining metal deposition with optical lithography using either a positive or negative photoresist process. Any method capable of providing fine pitch leads 70 on the first layer 64 of the lead tape 50 may be used.
[0046] The lead tape 50 has an upper portion 72 which is configured with a total width 76 of leads 70 which generally spans the semiconductor die 18 , but will be less than width 46 of die slot 22 (see FIG. 2). A lower portion 74 has a greater width 78 which may correspond generally to width dimension 41 of the lower beam 40 (see FIG. 2). Alignment apertures 80 , 82 are formed in the lower portion 74 to be coaxial along axes 84 , 86 , respectively, with alignment/retention posts 56 .
[0047] The upper portion 72 includes lead portions which contact the bond pads 90 of the dice. The lower portion 74 includes lead portions which are joined to substrate 16 .
[0048] In the embodiments of drawing FIGS. 3, 4, 5 and 5 A, the lead tape 50 is shown as being formed in the general shape of the letter “S.” A contact node 88 is formed in each lead 70 in the upper portion 72 by forming the upper portion as a bend. The node 88 is configured to be pushed away by contact with a bond pad 90 of a semiconductor die. The resistance to bending of the lead produces compression therebetween and enables consistent electrical contact with the bond pad 90 of a semiconductor die. Where the surfaces of the bond pads 90 of the semiconductor die 18 are essentially coplanar, contact between the bond pads 90 and the leads 70 is maintained. The compressive force between the semiconductor die 18 and the leads 70 is dependent upon the particular material of insulative layer 64 and its thickness, the thickness and material of conductive layer 66 , and lead displacement from the unbiased position which results from die insertion. Typically, the insulative layer 64 may vary in thickness from about 12 to about 300 μm. The preferred thickness of the conductive layer 66 is about 25 to about 75 μm. The total thickness of the combined first and second layers of the lead tape 50 is preferred to be from about 75 μm to about 100 μm.
[0049] The lower ends 92 of leads 70 are shown as bent to a nearly horizontal position for surface attachment to a substrate 16 .
[0050] The lower ends 92 are shown as having the insulative layer 64 removed to provide a metal surface for attachment by soldering or other method to a substrate 16 .
[0051] In a variation of the lead tape 50 shown in drawing FIG. 5A, the upper ends of the leads 70 , i.e. the leads in the upper portion 72 , may have both the insulative layer 64 and conductive layer 66 removed between the leads, thereby singulating them. Each lead 70 retains both layers 64 , 66 for retaining a required resistance to bending in each lead. Thus, each lead is independently compliant with respect to an inserted semiconductor die 18 to retain conductive contact with a bond pad 90 on the semiconductor die 18 .
[0052] An alternative embodiment of the interconnect lead tape 50 is depicted in drawing FIG. 6. The lower ends 92 of leads 70 are bent in the opposite direction from drawing FIGS. 5 and 5A and in addition, the insulative layer 64 is not removed from the lower ends 92 .
[0053] The lead tape 50 may be bent to the desired shape by a suitable stamping tool or the like, wherein the “at-rest” shape is uniform from tape to tape.
[0054] The placement of the module components, i.e. the die slot 22 , lower beam 40 , interconnect lead slot 44 , and recess 48 may be varied in the longitudinal direction 94 (see FIG. 3) of the plates, and may be apportioned in any convenient way between the first side 26 of one plate and the facing second side 28 of an adjacent plate.
[0055] Turning now to drawing FIGS. 7, 8 and 9 , several other embodiments of the modular socket 10 are illustrated. As depicted in drawing FIG. 7, a plurality of regular plates 14 A, 14 B and 14 C and an end plate 14 D, the plates providing for an interconnect lead tape 50 using a compressible elastomeric member 96 to bias the tape to the bond pads 90 of the semiconductor die 18 . The elastomeric member may be formed of silicone foam, solid silicone that has been perforated, or low durometer hardness silicone which is attached to the tape by adhesive. The elastomeric member 96 may be variably shaped as a narrow strip 96 A with limited biasing strength to a more general coverage 96 B with greater biasing strength. Both are illustrated in drawing FIG. 9. The narrow strip 96 A is intended to be used in the module design of drawing FIG. 7, and the high coverage member 96 B may be used in the module embodiment of drawing FIG. 8, wherein sufficient space is provided in the interconnect lead slot 44 for the elastomeric member. Preferably, the elastomeric member 96 A or 96 B comprises a single continuous unit extending across all of the leads 70 . Alternatively, a series of elastomeric members 96 may be arrayed on the tape 50 .
[0056] Referring to drawing FIG. 10, illustrated is another form of the invention, in which the compliant member of a module 12 comprises a projecting portion 100 of the plate 14 . The projecting portion 100 may be in the form of a ledge, as shown in the figure, and includes a longitudinal ridge 102 within a recess 48 in the side 26 . A multi-layer interconnect lead tape is attached, e.g. by adhesive to the projecting portion 100 and ridge 102 . The resulting node 104 in the lead tape 50 is forced away by an inserted die 18 and forcibly abuts the bond pads on the die surface 20 . The force holding the leads 70 against inserted bond pads 90 of a semiconductor die 18 will depend upon the distance 106 from the node 104 to the attachment point 108 of the ridge 102 . In order to provide the desired effect, the polymeric material of the plate 14 and projecting portion 100 is selected in combination with distance 106 and ledge thickness 110 . In this embodiment, it is unnecessary for the lead tape 50 to be aligned and retained on alignment posts.
[0057] Where a bare semiconductor die 18 has two rows of bond pads 90 , illustrated in drawing FIG. 11 as first row 112 and second row 114 , the lead tape 50 of the modular socket 10 may be adapted for lead contact with both rows. A lead tape 50 for providing contact with two rows 112 , 114 of bond pads 90 is shown in drawing FIG. 12. The tape 50 comprises three layers including a first insulative layer 64 , a second conductive layer 66 for contacting the first row 112 of bond pads 90 , and a third conductive layer 68 for contacting the second row 114 of bond pads on the die 18 . The first and second layers 64 , 66 are terminated at locations 116 , 118 , respectively, between the first and second rows 112 , 114 of bond pads. An elastomeric member 96 C such as a foam is attached to the third layer 68 and abuts the recess wall 120 . The member 96 C is compressed by insertion of the semiconductor die 18 into the socket and retains forced contact between the leads and bond pads.
[0058] As shown in drawing FIG. 13, the first (insulative polymer) layer 64 may alternatively be provided with holes 122 through which individual leads 70 of the third (conductive) layer 68 are preinserted for contact with the second row 114 of bond pads 90 .
[0059] The foregoing delineates several examples of the use of a multi-layer lead tape with means for contacting the bond pads of a bare die. Other types of biasing apparatus may be used for maintaining contact between interconnect leads 70 and the bond pads 90 of a semiconductor die 18 , including mechanical springs suitable for the miniature devices.
[0060] The plates 14 A, 14 B, 14 C, 14 D, etc. may be molded of a suitable insulative polymeric material, examples of which include polyether sulfone, polyether ether ketone (PEEK), or polyphenylene sulfide.
[0061] Following assembly of the modular socket 10 and attachment to a substrate 16 , the modular socket, or portions thereof, may be “glob-topped” with insulative sealant material, typically a polymer.
[0062] The socket 10 of the invention permits connection of bare semiconductor dice with very fine pitch bond pads to substrates, whereby short leads are used for improved performance. The semiconductor dice may be readily replaced without debonding of wires or other leads. Multiple semiconductor dice may be simultaneously connected to a substrate, and the apparatus permits high density “stacking” of a large number of dice. The socket uses leads which may be produced by well-developed technology, and is easily made in large quantity and at low cost.
[0063] It is apparent to those skilled in the art that various changes and modifications may be made to the bare die socket module of the invention, sockets formed therefrom and methods of making and practicing the invention as disclosed herein without departing from the spirit and scope of the invention as defined in the following claims. It is particularly noted that with respect to numbers and dimensions of elements, the illustrated constructions of the various embodiments of the modular bare semiconductor die socket are not presented as a limiting list of features but as examples of the many embodiments of the invention. | A modular bare die socket assembly for attaching a plurality of miniature semiconductor dice to a substrate. The socket assembly is comprised of a plurality of two-sided plates joined vertically in a horizontal stack, wherein each plate has a die socket for the removable insertion of a bare semiconductor die. A multi-layer interconnect lead tape has a plurality of lithographically formed leads bent on one end to form nodes for attachment to bond pads on the removably inserted semiconductor die, and having opposing ends connectable to the substrate. |
CLAIM OF PRIORITY
This application claims the benefit of U.S. Provisional Patent Application No. 60/617,798, filed Oct. 4, 2004. The contents of this provisional application are hereby incorporated by reference herein.
CROSS REFERENCE TO RELATED PATENT DOCUMENT
The present document is somewhat related to the copending and commonly assigned patent document “POWER LINE SENTRY”, Ser. No. 11/169,259. The contents of this somewhat related application are hereby incorporated by reference herein.
RIGHTS OF THE GOVERNMENT
The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty.
BACKGROUND OF THE INVENTION
Most modern-day wars are fought in urban environments. Large cities and small towns are the battlegrounds of choice by many present-day enemies. Unfortunately, this environment allows opponents to hide in numerous structures and amongst non-combatant civilians. These environments also provide a much harder and more complicated war to fight than existed in many previous conflicts. In simple terms, one reason for this is that walls tend to get in the way of today's battlefield communications and sensor technologies. One solution to this major new U.S. military problem lies in the time-honored profession of human reconnaissance and surveillance, especially with respect to enemy encounters that involve battles in urban neighborhoods. Unfortunately, it may take years before the United States can develop a capability to successfully gain information regarding this new type of enemy.
Consequently, there is little alternative except to approach a complicated problem with the use of high-technology systems, systems such as satellites and unmanned aerial vehicles, UAV's, used for surveillance purposes. Such systems may include silent, battery-powered, mini and micro-UAVs, i.e., silent unmanned aerial vehicles. Limited battery energy is however currently a major technological hurdle for all-electric silent unmanned aerial vehicles making them unsuitable for most urban battlefield environments. Using today's “off-the-shelf” secondary battery technology, a silent unmanned aerial vehicle (depending on aerodynamic capability and DC motor size) can perform for at most, 60 minutes out in an urban environment. This capability is of course partly consumed by the time it takes for the silent unmanned aerial vehicle to make a round trip away from and back to a base i.e., half, more or less of the silent unmanned aerial vehicle's energy can be lost on the round trip to and from a base. From a differing perspective, this limited capability additionally means a silent unmanned aerial vehicle dependent military unit must be located sufficiently close to an urban area to make the unmanned aerial vehicle effective as a surveillance tool. These considerations presently make current silent unmanned aerial vehicle technologies quite limited for real-time urban military operations.
At first blush one might be tempted to make a silent unmanned aerial vehicle smaller and lighter and thus decrease the level of the required propulsion energy. Unfortunately, however there are very severe physics limitations to the methodology of shrinking an unmanned aerial vehicle both in size and weight. Doing so creates a much more serious mission-capability dilemma in that as the size and weight of the unmanned aerial vehicle decreases, its payload capacity decreases not linearly, but exponentially i ! (Numbers of this type refer to the list of publications at the end of this specification.) Also, the aeronautical equations dependent on a “Reynolds” number are not usable for small air vehicles of, for example, less than 18 inches in size. Thus use of current-off-the-shelf (COTS) aeronautical CAD software to help design silent unmanned aerial vehicles of these sizes is not possible and one has no recourse but to “guess” a solution and hope it flies. This situation is worsened more by the fact that various aerodynamic instabilities are magnified as the vehicle size decreases ii . This particular problem can be seen in nature while small birds are landing or fighting-off gusts of wind. These birds have to flex and twist their wings and tails to compensate for instantaneous instabilities. Thus it may be appreciated that making electric UAVs smaller presents several technological obstacles.
As a result of these difficulties, existing and pending electric silent unmanned aerial vehicles are useful for only very limited DoD missions. Moreover the personnel that operate and maintain these vehicles must resign themselves to the fact that the battery-power problem is an existing limitation that unfortunately must be factored into the performed mission. Although a new battery technology offering significantly improved energy storage density may ultimately change this picture, it appears likely that this will not occur soon. If laptop computers are used for comparison, in view of their use of similar rechargeable batteries, it may be observed that over the last decade, battery technologies have barely progressed, progressed not nearly as rapidly as other computer related devices such as CPU speed and RAM capacity. In a similar vein of thought the electrically driven automobile is now being approached with use of hybrid electrical motor and fuel driven engine arrangements and with fuel cells but in a large part awaits the availability of rechargeable batteries of suitable energy storage density before becoming widely used.
The present invention is believed to offer at least a partial solution to these difficulties and to make the silent unmanned aerial vehicle a bit closer to being of practical value especially in a military environment. Theoretically silent unmanned aerial vehicle units made with use of the present invention arrangement for acquiring energy can operate in an urban field for an indefinite time interval (i.e., 24/7/365 capability) with infrequent “return-to-base” cycles being required. Most importantly this long term performance is available with use of presently available technology including present day secondary batteries.
The prior art shows numerous uses of inductively coupled electrical energy, energy coupled by way of a magnetic field rather than by electrical circuit continuity. These uses include for example the electric toothbrush, electrical measuring instruments and cellular telephones in the small energy quantity range and extend to submersible vehicles and other propulsion and underwater applications in the larger energy quantity range. These uses and others are included in the several prior art patents identified in the disclosure statement filed with the application of the present patent documents the contents of these issued patents is hereby incorporated by reference herein. None of these energy transmission inventions appear however to have involved an airborne surveillance vehicle or the possibly surreptitious or clandestine acquisition of inductively coupled electrical energy found in the present invention.
SUMMARY OF THE INVENTION
The present invention provides a random transmission line electrical current flow based charging for a battery used in a sub human sized surveillance aircraft.
It is therefore an object of the present invention to provide electrically energized silent unmanned aerial vehicle propulsion achievable with present day battery technology and other current technology.
It is another object of the invention to provide unmanned aerial vehicle recharging that is responsive to electrical current flow rather than operating voltage in a transmission line conductor.
It is another object of the invention to provide an aerial vehicle recharging energy source usage that also acts as a physical suspension element for an aircraft vehicle.
It is another object of the invention to provide a battery recharging energy source inclusive of “borrowing” electrical energy from a random convenient transmission line conductor that may be owned by a hostile entity.
It is another object of the invention to provide a battery recharging energy source that includes a physical latch for rigorous and resilient temporary engagement with a transmission line conductor.
It is another object of the invention to provide a clamp-on energy collector usable with a transmission line conductor.
It is another object of the invention to provide an aircraft mountable transmission line energy collector.
It is another object of the invention to provide a laminated alternating current transmission line energy collector that may be operated over a wide range of input current level.
These and other objects of the invention will become apparent as the description of the representative embodiments proceeds.
These and other objects of the invention are achieved by the method of recharging a propulsion battery in a sub human sized aircraft comprising the steps of:
locating a convenient alternating current electrical energy transmission line conductor in a geographic region occupied by said aircraft, said locating step including one of transmission line conductor magnetic field sensing and transmission line conductor visual sighting;
flying said aircraft into a position of physical engagement with said transmission line conductor, said physical engagement including an enclosing of said conductor within an incomplete magnetic circuit carried by said aircraft;
completing said magnetic circuit around said transmission line conductor in response to a command to physically move a magnetic circuit element portion thereof, said completing step including engagement of a controlling magnetic circuit latching mechanism;
collecting battery charging electrical energy from said completed magnetic circuit;
disengaging said magnetic circuit element and said latching mechanism and returning said aircraft to powered flight upon command;
repeating said locating through disengaging sequence of steps with one of said transmission line conductor and a new transmission line conductor upon command and as needed by said battery and said aircraft.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 includes the views of FIG. 1 a , FIG. 1 b and FIG. 1 c and shows a silent unmanned aerial vehicle according to the present invention in three different operating modes.
FIG. 2 includes the views of FIG. 2A and FIG. 2B and shows a silent unmanned aerial vehicle of the present invention type in greater detail.
FIG. 3 shows a part of the FIG. 1 and FIG. 2 silent unmanned aerial vehicle in yet greater detail.
FIG. 4 shows details of one arrangement for the magnetic core 202 and the movable jaw portion 204 .
FIG. 5 shows an achieved battery charging history.
FIG. 6 shows a block diagram of elements within a surveillance aircraft such as the aircraft 100 .
FIG. 7 shows details of an alternate surveillance aircraft arrangement usable with the invention.
FIG. 8 includes the views of FIG. 8 a , FIG. 8 b and shows details of an energy collection apparatus.
FIG. 9 shows a representative trickle charger circuit usable with rechargeable batteries of the type useful with the present invention.
DETAILED DESCRIPTION
A key concept to the present invention is that “Numerous overhead power transmission lines that frequent most urban areas may be utilized by silent unmanned aerial vehicles to inductively recharge themselves while perched”. Theoretically these “power line-rechargeable” silent unmanned aerial vehicle units should be able to operate out in the urban field for an indefinite amount of time (i.e., 24/7/365 capability) with very infrequent “return-to-base” cycles being required. A typical urban military operation may for example involve launching swarms of present invention silent unmanned aerial vehicles weeks or even months before troops arrive to seek-out and terminate various combatants. For example, Special Operations troops may pre-program these vehicles to fly to local power lines near the urban areas of interest. If the duration of flight exhausts the battery power, then the silent unmanned aerial vehicles may simply locate the nearest power line for a temporary recharging. Once recharged, the silent unmanned aerial vehicles can continue their flight towards the urban theater destination. Upon reaching the theater, the silent unmanned aerial vehicles may then fly high above the area to visually, infrared, radar and possibly audibly locate particular targets of interest. Such silent unmanned aerial vehicles can then transmit intelligence-related information, from a comfortable distance, back to a command center. Chemical and biological sensors may also be mounted onboard the aircraft to warn of impending threats.
FIG. 1 in the drawings shows three events in the operating sequence of an electrical silent unmanned aerial vehicle according to the present invention, these events appear in the FIG. 1 a , FIG. 1 b and FIG. 1 c drawing views. In the FIG. 1 a view a battery operated multiple propeller driven silent unmanned aerial vehicle 100 has been launched and is conducting an optical surveillance operation over an open terrain area 102 . The silent unmanned aerial vehicle 100 may be in real-time or store and dump communication with a command center or other user. In the FIG. 1 b drawing the silent unmanned aerial vehicle 100 continues to examine a surveillance area 102 but has now attached itself to one conductor 104 of a convenient electrical energy transmission line 106 where recharging of its electrical battery ensues and the surveillance activity is focused on a selected area 102 adjacent to the transmission line 106 . The silent unmanned aerial vehicle attachment represented in FIG. 1 b may result from a flight path that is either generally perpendicular to or tangent to the transmission line conductor 104 as is discussed in detail below. In the FIG. 1 c drawing the silent unmanned aerial vehicle 100 has located persons 108 of interest in a particular mission and is maintaining these persons under continuous close surveillance while circling in a suitable flight path and also while communicating the collected video data back to a command center as is implied by the antenna at 110 .
Events shown in the FIG. 1 b drawing suggest a particular focus of the present invention. In this drawing the silent unmanned aerial vehicle 100 has attached itself to one phase conductor 104 of a high-voltage electrical energy transmission line 106 previously located by the silent unmanned aerial vehicle or known to exist from prior knowledge of the area under surveillance. The phase conductor 104 may be operating at any of the voltages used for electrical energy distribution or transmission, any voltage between 100 volts and 1,000,000 volts for example. Preferably however the electrical current flowing in the conductor 104 is in the several tens of amperes to hundreds of amperes range. The operating frequency of the transmission line 106 is assumed to be of the 50 Hertz or 60 Hertz frequency used in essentially all of the world. Higher frequency transmission lines if they happen to be found by the silent unmanned aerial vehicle are even more advantageous for present energy collection purposes.
FIG. 2 in the drawings includes the views of FIG. 2 a and FIG. 2 b and shows the silent unmanned aerial vehicle 100 itself and the energy collection apparatus 200 for the silent unmanned aerial vehicle in greater detail. In the FIG. 2 a drawing the silent unmanned aerial vehicle appears in an oblique view wherein a lens array for the video camera included in the airframe appears at 210 in a lower part of the vehicle or aircraft and the energy collection apparatus 200 is shown to be attached to an upper part of the vehicle by way of a mounting bracket appearing at 208 . The FIG. 2 a energy collecting apparatus 200 is represented as an open jawed magnetic core 202 having a movable jaw portion 204 closable onto a mating face 216 or on to a magnetic coupler of the core 202 by an actuating rod 214 following engagement with the energy supplying transmission line conductor 104 . Engagement of the face 216 with a mating or interleaved face 217 of the movable jaw portion 204 as shown in FIG. 4 or in some other manner is achieved.
A motor or solenoid mechanism within the airframe of the FIG. 2 aircraft may be used to move the actuating rod 214 into a closed position upon receipt of a latching command from a ground controller or an internal computer. In the closed jaw condition the silent unmanned aerial vehicle is both securely attached to the transmission line conductor 104 and thus precluded from disengagement at the hand of wind bursts or other phenomenon and is also providing of an energy collecting closed magnetic circuit around the transmission line conductor 104 . Significantly, in the absence of another conductor completing an electrical circuit from the transmission line conductor 104 or from the silent unmanned aerial vehicle 100 to earth etc., there is no transmission line voltage-dependent current flow to cause arcing damage to the silent unmanned aerial vehicle 100 in the FIG. 1 and FIG. 2 suspended condition. This desirable isolation prevails regardless of the 69 kilovolt or other operating potential of the transmission line conductor 104 .
Magnetic circuits having physically open and closed operating positions as shown in FIG. 2 a are known in the art and are to be found for example in the “Tong Test” and “Amprobe” portable current measuring instrument field where such a two position magnetic circuit enables current magnitude measurement to be accomplished without interruption of current flow in the measured circuit. The names “Tong Test” and “Amprobe” are believed to be trademarks of The General Electric Company and the Florida-based Advanced Test Products Company. One arrangement of the movable yet magnetically integral joints in such a magnetic circuit is shown in greater detail in the FIG. 4 drawing herein, another appears at 800 in the FIG. 8 drawing. Magnetic circuits of greater ferrous cross sectional area than those used in measuring instruments are of course possible and are preferable in response to the greater energy needs of the present invention. A movable magnetic circuit measurement instrument inclusive of a magnetic coupling is shown in the U.S. Pat. No. 2,146,555 identified herewith.
In the FIG. 2 b drawing the silent unmanned aerial vehicle also appears in an oblique view wherein a lens array for the video camera included in the airframe appears at 210 in a lower part of the aircraft and the energy collection apparatus 200 is shown to be attached to an upper part of the vehicle by way of an upper wing received bracket appearing at 218 . Notably in the FIG. 2 b drawing the bracket 218 and the energy collection apparatus itself are rotated by ninety degrees from that shown in the FIG. 2 a drawing. This rotation enables the FIG. 2 b silent unmanned aerial vehicle to engage a transmission line phase conductor 104 during a lengthwise or axial tangency approach to the conductor rather than from the substantially orthogonal approach contemplated for the FIG. 2 a silent unmanned aerial vehicle. As the combination of the FIG. 2 a and FIG. 2 b drawings may suggest the collection apparatus 200 may be mounted in any rotational position with respect to the airframe 210 or also may disposed in a movable and operator controllable arrangement enabling any angled approach of silent unmanned aerial vehicle to a transmission line conductor. The non orthogonal of these possible approaches are of course useful in permitting a more gradual deceleration or acceleration of the silent unmanned aerial vehicle in the transition from flying to parked or docked status and vise versa.
As is represented at 220 in the FIG. 2 a and FIG. 2 b drawings an additional video camera or a time shared camera input port associated with the camera assembly at 210 may be disposed in the tail or other convenient location of the silent unmanned aerial vehicle in order to provide a remote operator with a view of the engaging and disengaging of the silent unmanned aerial vehicle with respect to a transmission line conductor. Use of a second camera or coupling between camera locations 210 and 220 using for example fiber optic paths within the silent unmanned aerial vehicle are preferable arrangements for this engaging and disengaging or docking and undocking view from the silent unmanned aerial vehicle. The sensing of magnetic field strength surrounding a transmission line conductor, as is described in the identified U.S. Pat. Nos. 3,197,702 and 4,818,990 may be used as an additional aid in the performance of such a docking maneuver. Closure of the movable jaw member 204 onto a mating face 216 or a magnetic coupling portion of the core 202 by actuating rod 214 may also be viewed critically from a camera location such as that shown at 220 .
In FIG. 3 there is shown the pin 302 by which the movable jaw member 204 is made to be closable onto a mating face 216 of the core 202 by the actuating rod 214 . A second rotatable pin member 304 provides for similar rotation between the movable jaw 204 and the partially shown actuating rod 214 . The FIG. 3 drawing also shows the winding bundle 212 and leads 300 by which the magnetic flux from the transmission line conductor 104 is enabled to generate electrical energy for use in battery charging and other purposes in the silent unmanned aerial vehicle. As indicated in the FIG. 3 drawing the transmission line conductor 104 is often of the hollow or annular shape found desirable in present day long distance high-voltage transmission lines or alternately may be of the stranded or solid conductor variety. Often such conductors are fabricated to have a circular tongue and groove configuration as is suggested in the FIG. 6 drawing. The construction of conductor 104 and the relative size of conductor 104 with respect to the diameter 306 of the core 202 are of little if any importance in determining characteristics of the inductive energy collection arrangement of the invention. Visualization of a drawing similar to FIG. 3 for the rotated or rotatable energy collection arrangements discussed in connection with FIG. 2 b is believed to be within the skill of persons familiar with this art.
Once conductor 104 becomes enclosed by the core 202 and the closed movable jaw 204 this entire configuration becomes an electromagnet as long as there is current flowing in the transmission line conductor 104 . The problem here is that the two parts of the core 202 now “attract” each other. This is a significant consideration during the delatching process. We find a simple solution to this consideration exists in the form of shorting the two wires 300 together; this stops the attracting fields and allows disengagement. A simple relay or MOSFET can be used to achieve this function in a practical embodiment of the invention. A resistor in series may help dissipate the heat generated. FIG. 4 in the drawings shows one arrangement for the core 202 and the movable jaw 204 that may be used in the regions 308 and 310 , the regions of core and movable jaw intersection within the magnetic circuit of the FIG. 3 drawing. As indicated in the FIG. 4 drawing it is preferable that the core 202 and the movable jaw each be of the laminated nature frequently used in alternating current machinery flux paths in order to limit the energy loss effects of eddy currents induced in these components. Lamination thickness used in these components is somewhat of a tradeoff between the low losses achieved with thin laminations and the physical rigidity, convenience and maintained joint alignment at 308 for example provided by thicker laminations. Thicker laminations representing the core 202 are shown at 400 , 402 and 404 in the FIG. 4 drawing where they are interleaved with the also thick laminations 406 , 408 , and 410 that are part of the movable arm 204 in the jaw closed or integral core condition.
As implied by the illustrated curvature of the laminations shown in FIG. 4 , the FIG. 4 drawing represents the intersection of core and movable arm occurring at 308 in FIG. 3 . A larger number of laminations than are represented in FIG. 4 and other drawings herein may be desirable for use in the invention in order to generate a greater extraction of energy from the transmission line 104 for present invention usage. Other arrangements of the lamination intersections at 308 and 310 are of course feasible and are perhaps more practical than that shown in FIG. 3 and FIG. 4 in some instances. The use of machined surfaces on the core 202 , in the facial area 216 , and the use of similar and complementing machined surfaces on the movable member 204 together with a sliding motion engagement of machined surfaces by the movable arm 214 are particularly attractive alternatives to the FIG. 4 arrangement of these components.
The core 202 and winding bundle 212 are of course in the nature of a current transformer device as is often used in the electrical measuring art for determining the magnitude of transmission line and other alternating currents. Such current transformers are available from numerous sources in the electrical art; including for example Ohio Semitronics, Inc. of Hilliard, Ohio and CR Magnetics, Inc. of St. Louis, Mo. The latter manufacturer offers a line of “Split-Core” current transformers identified as the type CR 3110 that are of interest in view of their jointed magnetic circuit and other details appearing relevant to the needs of the present invention. These CR Magnetics transformers if not per se usable in the present setting provide a closely related standard item starting point from which an optimum apparatus for use at 200 in the present invention may be achieved.
FIG. 5 in the drawings shows the results of an experiment in which an 8.4-volt Nickel Metal Hydride battery has been charged by inductive coupling with an average 54-ampere current flowing in a 7.15 kilovolt residential power distribution transmission line, i.e., charged in the manner of the present invention. In the FIG. 5 drawing an inductively generated current flow of about 150 milliamperes is used to trickle-charge i.e., is applied to a Nickel Metal Hydride battery of some 900 milliampere-hours electrical capacity and maintained for three and one-half hours in order to increase the battery terminal voltage from an initial largely-discharged value of about 8.1 volts to a final value of about 9.6 volts. A simple trickle-charging circuitry, which is suitable for most NiCad and NiMH battery chemistries, can be utilized to generate the data in FIG. 5 , such a circuit is for example shown in the FIG. 9 drawing herein. Assuming such a trickle-charging sequence is achieved, the power line basically can supply a sufficient amount of energy over a period of time for any UAV configuration regardless of the size of the battery. The amount of energy being transferred is dependent on the amount of current flowing in the transmission line conductor. Assuming the current in the transmission line is held constant, the amount of time required to recharge the battery is proportional to its energy capacity in milliamperes-hours. The larger the milliampere-hour capacity, the longer the UAV may sit and recharge.
A more advance version of the invention can entail replacing the trickle-charging circuit with a fast-charger as recharging circuit. Chips such as the Maxim MAX1772 multichemistry battery charger can be utilized in this case to recharge, for example, lithium batteries which require a more sophisticated charging scheme than a trickle-charger. The FIG. 5 graph is viewed as a confirmation of the overall principle of battery charging by way of inductive coupling from a current-conveying transmission line conductor rather than being an illustration of a fully developed embodiment of the invention. This is true especially since battery voltages of greater magnitude than 9.0 are viewed as being most practical for silent unmanned aerial vehicle propulsion over militarily realistic distances. Time for charging is of course the hidden variable in the charging of the present invention; even though the amounts of energy represented in FIG. 5 are relatively small, even these amounts of energy become significant for present usage when the charging event is extended over a sufficient charging time interval.
FIG. 6 in the drawings shows a coarse general block diagram of electrical components to be included in the silent unmanned aerial vehicle of the present invention; a brief description of components in this diagram not already discussed at length follows. The rechargeable battery used to energize the propulsion, control and mission related components of a present invention silent unmanned aerial vehicle appears at 600 in FIG. 6 . This battery is provided with recharging energy by the induction pickup assembly 200 in FIG. 5 and this energy is supplemented by a solar cell array 622 operated by the solar cell controller 624 . Energy flow between these recharging sources and the battery 600 and each of the loads shown in FIG. 6 is accomplished by a power bus 628 . Functional control over each of these load/sources is achieved by computer 616 and a computer operated bidirectional communication bus 626 . The charged/discharged condition of battery 600 is for example sensed by the status circuitry indicated at 629 and communicated to the operator of the vehicle by way of the bus 626 and computer 616 and the radio frequency circuits at 614 . This status is of course important in determining need for a parking and recharging time interval and precluding loss of a totally discharged silent unmanned aerial vehicle. Real time sensing of battery charging activity is accomplished by way of the bus 626 and a sensing apparatus 610 ; this precludes attempts to recharge from a transmission line conductor already disabled by military action for example or indicates the need to locate a more active transmission line conductor carrying a greater current.
On and Off control of the silent unmanned aerial vehicle driving motor 604 as well as speed control of this motor is determined by the computer 616 and the bus 626 by way of an electronic throttle package 606 . Low loss switching circuitry in lieu of analog circuits are preferred for use in the electronic throttle package 606 ; this circuitry may also include reverse energy flow provisions in order to take advantage of propeller windmill-generated energy occurring during silent unmanned aerial vehicle diving or landing events. Command signals and surveillance data signals are communicated between the silent unmanned aerial vehicle computer 616 and a ground based station by way of the radio frequency receiver and transmitter 614 and an associated antenna 615 . Alternating current energy received from the magnetic induction coupling with a transmission line is modulated in intensity as well as being rectified by an electronically varied controller 608 ; this control may include either shunt or series control of magnetic circuit output level as is appropriate in view of the saturation and other characteristics of the core of the pickup assembly 200 .
Opening and closing of the pickup core movable arm 204 is achieved in the FIG. 6 system by an actuator 612 controlled from the bus 626 in a manner observable by one of the silent unmanned aerial vehicle cameras, the docking camera 618 . Energy transmission line proximity sensing as may be used as an aid to silent unmanned aerial vehicle docking on a transmission line conductor is provided by the bus extension at 613 by which power line proximity data received from the assembly 200 in an open jaw condition is communicated. The downward directed data camera 620 is used to provide the surveillance data sought by the silent unmanned aerial vehicle; this data may be communicated in real time by way of the bus 626 , the computer 616 and the receiver/transmitter 614 or alternately may be stored in the computer 616 or an auxiliary memory for dumping upon inquiry or at a later convenient time. Orientation of the camera for scanning or field of view enhancement may be used if needed. Orientation of the pickup core movable arm 204 into positions other than a fixed axial or fixed lateral position may be accomplished with another controller apparatus operating from the busses 626 and 628 .
FIG. 8 in the drawings shows an alternate and perhaps more real world considered arrangement of the energy collection apparatus 200 usable with the surveillance aircraft of the present invention. In the FIG. 8 a drawing of this group the energy collection apparatus 200 is shown to include a magnetic core portion 202 having the two flat faced surfaces 800 and 802 , a core portion that is closed magnetically by the mating flat faced surfaces 813 and 815 of the movable jaw portion 205 . Both the energy collection apparatus 200 and the movable jaw portion 205 are made of magnetic laminations in the FIG. 8 drawings and the uppermost of these laminations are provided with longer length to orient the movable arm 205 in an off vertical closed position, as appears in the FIG. 8 b drawing. The longer upper arm 840 with respect to lower arm 842 of the core 205 aids in aircraft landing or docking and retention on a transmission line conductor. FIG. 8 a also shows a first torsion spring 810 , a solenoid 804 , a latch member 806 and a second coil spring 808 used during movements of the FIG. 8 a power transmission line conductor trigger 805 and latch 806 . A rotational pin for the movable jaw portion 205 , the latch 806 and the springs 808 and 810 appears at 832 in the FIG. 8 b drawing.
The portion of the trigger 805 and latch 806 engaged by the transversely moving incoming energy conductor from which the battery of the aircraft is charged is designated at 812 in the FIG. 8 drawing. During this movement the landing aircraft may for example be moving initially at a velocity of 35 miles per hour or 616 inches per second and may decelerate to zero velocity over a distance of about 0.75 inch while moving the trigger 805 and latch 806 and winding the spring 808 ; this sequence may for example occur in a time near 1.22 milliseconds and achieves closing of the latch 806 and core 202 . During such deceleration the aircraft may rotate around the transmission line conductor however such rotation is acceptable to both aircraft and transmission line under normal conditions. In the wound condition spring 808 tends to open the latch 806 and to urge the movable jaw 205 toward an open position; the spring 810 tends to urge the movable jaw toward the closed position—by way of the pin 830 .
The latch 806 and movable jaw 205 are retained in the closed condition by way of the radial notch 846 in the latch pivot area; this notch is engaged by the stop element 844 connecting to the solenoid pin 820 as a cam surface of the latch 806 forces the solenoid pin to move rightward in FIG. 8 b against the coil spring 848 during movable jaw 205 closure. The pin 820 of solenoid 804 is shown to include such a spring 848 and to appear in an extended condition, represented at 843 in the FIG. 8 b drawing. Windings used to control operation of the FIG. 8 solenoid 804 for latch opening are omitted for the sake of clarity in the FIG. 8 drawings. Similarly windings used for energy collection during the recharging process are also omitted for the sake of clarity on the core portion 202 in FIG. 8 a and FIG. 8 b . Opening of latch 806 occurs on command of a signal from within the aircraft and involves momentary closure of solenoid 804 at 843 to release the latch 806 , open the movable jaw 205 , unwind the spring 808 and “expel” the energized transmission line conductor from within the core 202 . As a result of this expulsion the aircraft 100 is moved backward and forced clear of the transmission line conductor and is ready for powered flight again.
FIG. 7 in the drawings shows an alternate airframe arrangement of a power line sentry according to the present invention. In the FIG. 7 drawing a single pusher propeller-driven aircraft 700 is used to contain the FIG. 6 or other components in an overall arrangement that is believed to be lighter in weight and lower in cost than with the aircraft heretofore shown since there is now only a single motor versus three in FIG. 2 . It is helpful however to appreciate that, the advantage of the aircraft previously shown in FIG. 2 is agility since such a ducted-fan aircraft has much more maneuverability then a single engine aircraft as shown in FIG. 7 . This in turn makes it easier to land or park on a transmission line conductor.
Additionally included in the FIG. 7 power line sentry 700 are a second visible spectrum camera 715 , shown to be mounted in a forward-looking position in the aircraft 700 , and a pair of Hall effect or other Gauss sensors 710 a and 710 b that are disposed in forward looking aircraft positions where they can be used to sense the magnetic fields emanating at 60 Hz or 50 Hz from the transmission line during an approach of the aircraft 700 to a transmission line conductor or other energized magnetic field emitting target element. Notably the Gauss sensors 710 a and 710 b are disposed on widely separated parts of the aircraft 700 in order to provide the greatest possible distinction between the two received signals. Notably in addition, since the spit-core current transformer 200 is open at this time it is basically configured as a solenoid. As such it can have a dual-use in that it too can be uses as a third magnetic sensor. These three magnetic sensors moreover may be configured with their sensing axis to be in line with each of the three X, Y, and Z spatial coordinate axis. The outputs from these sensors are fed to the computer 616 through the bus 626 to be used to guide the aircraft 700 in for a landing on the transmission line conductor. The FIG. 7 aircraft 700 is also provided with a mechanical trigger mechanism, similar to that disclosed in FIG. 8 , and shown at 730 in FIG. 7 , in which kinetic energy developed at the time of aircraft 700 docking on a transmission line conductor may be converted into potential energy for storage and use during disengagement of the aircraft 700 from its docked condition and returning to a flight supported condition. This stored energy can supply a helpful initial sendoff push for the aircraft 700 . The previously described infrared camera is represented in the downward looking position at 210 in the FIG. 7 drawing.
FIG. 9 in the drawings shows a representative trickle charger circuit usable with rechargeable batteries of the type employable with the present invention. In the FIG. 9 circuit a full-wave bridge rectifier circuit 900 is connected to a transmission line conductor pickup coil of the type shown at 200 in FIG. 2 and 200 in FIG. 8 and the output of this circuit applied to a rechargeable battery 902 of the type also used in obtaining the FIG. 5 data. Battery and charger condition indicating light emitting diodes are shown at 904 and 906 in the FIG. 9 drawing and these are connected to have unusual responsivity to the indicated battery voltage and charger output voltage. A switching circuit is used at U9 in the circuit 906 to ensure sensitivity and accuracy of this light emitting diode 904 indication. Remote data indicating lines appear at 904 in FIG. 9 and provide high impedance filtered signals suitable for remotely indicating battery and charger voltages to an operator via the bus 626 in FIG. 6 for example.
The foregoing description of the preferred embodiment 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. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the inventions in various embodiments and with various modifications as are suited to the particular scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled. | A surveillance aircraft recharging system based on energy collection by magnetic induction from the current flowing in a randomly selected alternating current transmission line conductor. The charging energy originates in the magnetic field surrounding the current carrying conductor and is obtained by way of a laminated magnetic circuit surrounding the current carrying conductor and disposable in both an open and transmission line receiving state and a closed and energy collecting state upon command. Latching of the magnetic structure into a condition providing physical suspension stability for the host aircraft as well as an efficient magnetic circuit are provided. Latching of the magnetic structure includes a docking aircraft kinetic energy storage sequence assisting in aircraft deceleration and also providing saved energy useful during an undocking sequence. |
BACKGROUND OF THE INVENTION
This invention relates to drive and cutting mechanisms adapted for the slicing of textile materials such as continuously produced fusion bonded nonwoven carpets. More particularly this invention relates to a dual, series ball screw and ball nut array to drive a reciprocating cutter and cable connection, and a cutting mechanism utilizing the array.
U.S. Pat. Nos. 3,127,293, 3,657,052 and 3,972,254 describe devices for producing nonwoven carpets and other textile materials wherein a flexible sheet is continuously advanced to a cutting position. At the cutting position a cutting blade reciprocally traverses the width of the sheet to slice the sheet in a predetermined path. In one cutting mechanism, such as described in U.S. Pat. No. 3,972,254, a plurality of cutting elements are secured to an endless belt which is sprocket driven in a reciprocating fashion. In another cutting mechanism, one or more cutting elements are carried on a rope which reciprocally travels in a substantially linear path in the desired cutting plane. Each of these cutting mechanisms requires complex and massive arrangements of driving elements which are cumbersome and subject to breakdown. For example, in a rope drive cutting mechanism of the type described, a plurality of sheaves are pendulum driven. This system takes up considerable space, and tends to be inefficient due to wasted motion and breakdowns caused by wear on the numerous bearings in the array.
SUMMARY
The present invention provides a space-saving drive mechanism, and a cutting mechanism utilizing the drive mechanism, which is simple in construction and efficient in operation, particularly by reducing the large number of pulleys utilized in existing mechanisms. In the drive mechanism of the invention, a pair of ball screws are aligned axially, one of the ball screws being stationary and the other being axially movable. Each ball screw carries a ball nut thereon and the ball nuts are linked by a tubular member or similar element which rotates with the ball nuts. The pitch and thread leads of the opposing ball screws and nuts are matched but of opposite hand. A multigrooved pulley is carried on one of the ball nuts or on the linking member for rotation therewith. A reciprocating driving force acts on the translatable ball screw with the result that the reciprocating rotary motion imparted to the ball nut carried thereon is transferred to the multigrooved pulley. If the drive mechanism is utilized in a cutting mechanism wherein a rope or the like is operatively wrapped around the pulley and another idler pulley, the rope will also reciprocate in a predetermined path. One or more cutting elements mounted on the rope will thereby slice material moving transversely in the path of the cutting element or elements.
DETAILED DESCRIPTION
The invention is more fully described in the accompanying drawing wherein:
FIG. 1 is a partly schematic, elevational view showing some basic elements in a mechanism for cutting a textile material of the fusion bonded type;
FIG. 2 is a side view of the cutting mechanism portion of FIG. 1, further showing elements of the drive and cutting mechanisms of the invention;
FIG. 3 is a section along the line 3--3 of FIG. 2;
FIG. 4 is a partly schematic section along the line 4--4 of FIG. 2; and
FIG. 5 is a view similar to FIG. 4 showing another position of elements of FIG. 4 when actuated.
With reference to the drawing, FIG. 1 shows one use of the mechanisms of the invention, such as the slicing of nonwoven textile material produced as described in U.S. Pat. No. 3,127,293. In this application, as shown in FIG. 1, yarn 11 looped between backing materials 12 and adhered thereto by suitable adhesive exits from a curing oven 13 through a pair of guide rolls 14. The textile material is sliced across its width as it advances from the oven by a cutting element such as traversing knife blade 15. Blade 15 (see FIG. 2) is mounted on a carriage 16 having spring loaded shoes 17 which track in a way 18 affixed to a suitable support number 19 (FIG. 1). Carriage 16 is affixed to a rope 20 or the like (for example, a cord, chain or cable) by a suitable connector such as clamp 21. In the conventional arrangement shown in FIG. 1, the cutting blade 15 is reciprocated by reciprocation of a rope to which the blade carriage is connected. In a conventional drive mechanism for reciprocating the rope, a pendulum system is utilized which is linked to the rope through a plurality of pulleys (not shown). As the yarn 11 is sliced, two sheets of textile material such as carpets 24 are formed which are then taken up on rolls 25 after passing over pin rolls 26.
In one embodiment of the drive mechanism of the invention (FIGS. 2-5), an endless rope 20 carrying the blade 15, is wrapped around a driven pulley such as sheave 27 and an idler pulley such as sheave 28. Sheave 27 is multi-grooved to provide frictional engagement with rope 20. Sheave 28 is singly grooved. It will be understood, however, that the invention may be used with operating elements other than ropes, such as belts, chains, cables or the like. In the embodiment of the invention applicable to cutting mechanisms for slicing textile materials, however, it is preferred to use a rope to move the cutting element. Sheave 28 is skewed from the vertical an angle alpha, as shown in FIG. 3, for reasons explained below.
With reference to FIGS. 4 and 5, one embodiment of the drive mechanism of the invention includes a ball screw 29 which is held stationary on a support 29a by a set screw 30 which locks onto ball screw shaft 31. A ball nut 32 rotatably rides on ball screw 29 and carries sheave 27 which is affixed to ball nut 32 by set screws 32a. A torque and thrust tube 33 is connected to one end of ball nut 32 through a flange 33a. Preferably, tube 33 is rotatably supported in a sleeve journal, preferably a ball support sleeve 34. The opposing flanged end 33b of tube 33 is connected to a second ball nut 35 of hand opposite that of first ball nut 32. Ball nut 35 is rotatably carried on a second ball screw 36 which is translatable axially with respect to first ball screw 29 but is not rotatable.
Ball nuts 32 and 35 in combination with respective ball screws 29 and 36 are known elements such as the systems available from the Saginaw Steering Gear Division of General Motors Corporation. These power transmission screw systems include return tubes 37 for the ball bearings 38. As the screw and nut rotate relative to each other, the bearing balls divert from one end and are carried by ball guides to the opposite end of the nut. This recirculation permits unrestricted travel of the nut in relation to the screw and thus provides highly efficient power transmission when a driving force is applied to either the screw or the nut. For example, it is estimated that the efficiency of a ball screw to ball nut thrust to rotation motion conversion is not less than 80% and the efficiency of translating a ball nut restricted to rotation by ball splines is not less than 90%, thus yielding an operating mechanism whose efficiency is not less than 72%. Similarly, tube 33 and its support sleeve 34 is a conventional arrangement such as the combination of linear and rotary motion provided by ball sleeves and shafts such as "ROTOLIN" (trademark) ball bearing types ML or MLF available from Landis & Gyr, Inc., Elmsford, New York.
Ball screw 36 has a shaft 39 which is actuated by an actuator rod 40 linked to the shaft through a clevis or yoke 41. Any suitable driving force capable of providing reciprocal motion may be used to actuate the drive mechanism of FIGS. 4 and 5 through rod 40, such as an hydraulic piston activator the speed of which may be adjusted as desired.
In operation, a translating but not rotating driving force reciprocates ball screw 36 from a rest position as shown in FIG. 4 through a stroke with the result, as shown in FIG. 5, that ball nut 35 is rotated and translated a distance equal to a fraction of the stroke, such distance being dependent upon various dimensions of the elements of the array such as the pitch of the threads of ball screws 36 and 29. For example, in preferred embodiment the geometry of ball screw 29, ball nut 32 and sheave 27 is matched to the geometry of ball screw 36, ball nut 35 and sheave 28, particularly with respect to pitch and thread lead, except for opposite hand. Sheave 27 will thereby be translated the same fractional distance as ball nut 35, the resulting rotation causing rope 20 thereon to be reciprocated over a distance which is a function of the stroke of the drive mechanism. When, for example, the input stroke is twice the translation distance of ball nut 32 and sheave 27, a two to one mechanical advantage is obtained. If the screw leads are 1/2 inch and the input stroke is 6 inches, nut 32 will translate 3 inches and sheave 27 will make six revolutions. When the drive mechanism is used to reciprocate a rope 20 between sheaves 27 and 28 (FIG. 2), the distance of travel of the rope will depend upon the foregoing conditions and the elements of the array may be sized accordingly.
As indicated above, however, the use of a multi-grooved sheave 27 requires that sheave 28 be skewed (while providing matched thread leads and hands of sheave 27, ball nut 32 and ball screw 29) so that the exit and entry positions of the rope 20 on sheave 27 will be substantially stationary in space as sheave 27 rotates and translates. This is shown in FIGS. 4 and 5 wherein it will be seen that rope 20 remains on center in both the rest position shown in FIG. 4 and in the stroke position shown in FIG. 5. It will be further noted that the skew angle alpha (FIG. 3) is equal to the angle alpha formed by the center line and the line of deviation between the entry and exit positions of rope 20 on sheave 27 (FIG. 4). In consequence, rope 20 remains substantially in the same path relative to sheaves 27 and 28, and cutter blade 15 likewise can be maintained in substantially the same linear path relative to ground. For example, if it is desired to reciprocate the blade and its carriage along guideways 17.66 feet, a sheave 27 as well as ball screws and ball nuts will be selected having 1/2 inch leads. When combining these dimensions with a sheave 27 having a pitch diameter of 11.13 inches and wrapping the rope 20 six and a half turns around sheave 27 while utilizing an input reciprocating stroke of 6 inches, sheave 27 will be caused to rotate six turns and translate 3 inches. Rope 20 will thereby be caused to alternately play out 17.66 feet and rewind 17.66 feet while maintaining a path which remains substantially parallel to the guided way. It will, of course, be understood that other screw leads, strokes and sheave diameters may be used depending upon the desired output and input stroke lengths.
It will be understood that the invention is not limited to the foregoing description and the embodiment illustrated by the appended drawing but extends to all mechanisms within the scope and spirit of the appended claims. | Dual, series ball screw and ball nut array for reciprocating a cable and a cutting mechanism utilizing the array. The first ball screw is stationary while the second is moveable, spaced apart and axially aligned with the first ball screw. Ball nuts are rotatably carried on each ball screw and the ball nuts are connected as by a tube. A drive means such as an hydraulic piston activator reciprocates the movable ball screw, thereby translating and rotating the second ball nut likewise the ball nut carried on the stationary ball screw. A pulley on either ball nut or on the connecting tube activates a cable connected thereto. A cutter connected to the cable is thereby reciprocated for slicing action. |
This is a continuation of application Ser. No. 535,271 filed Dec. 25, 1974 now abandoned.
The present invention relates generally to materials of construction of nuclear reactors and is more particularly concerned with a novel zirconium-base alloy nuclear reactor structural member or body having unique corrosion resistance, ductility and load-carrying capacity (resistance to stress corrosion) and possibly corrosion resistance in the irradiated condition.
CROSS REFERENCE
This invention is related to that disclosed and claimed in copending patent application Ser. No. 535,419, filed Dec. 23, 1974, abandoned in favor of Ser. No. 934,948 filed Aug. 18, 1978, allowed, in the names of Rodney E. Hanneman, Daeyong Lee and Craig S. Tedmon, Jr., which is based on the concept that a small amount of lanthanum or praseodymium will substantially improve the slow strain rate ductility of certain zirconium-base alloys and on the additional concept that these new zirconium alloys and certain others in the irradiated condition can under certain circumstances have surprising load-carrying capacity.
BACKGROUND OF THE INVENTION
Important requirements for materials used in boiling water nuclear reactor construction include low absorption for thermal neutrons, corrosion and stress corrosion resistance and mechanical strength. Zirconium-base alloys sufficiently satisfy these requirements that they are widely used for such purposes, "Zircaloy-2" (containing about 1.5 percent tin, 0.15 percent iron, 0.1 percent chromium, 0.05 percent nickel and 0.1 percent oxygen) and "Zircaloy-4" (containing substantially no nickel but otherwise similar to Zircaloy-2) being two of the important commercial alloys commonly finding such use. These alloys, however, are not nearly all that one would desire, particularly in respect to useful service life, despite many efforts of others during the past two decades to improve them.
Mainly, these efforts have been aimed at improving corrosion resistance and usually this has involved changes in composition. Thus, in U.S. Pat. No. 3,005,706, it is proposed that from 0.03 to 1.0 percent of beryllium be added to zirconium alloys intended for use in conventional boilers, boiling water reactors and similar apparatus. Similarly, in U.S. Pat. Nos. 3,261,682 and 3,150,972, cerium and/or yttrium additions and a calcium addition, respectively, are proposed as zirconium alloy additions in like proportions for the same purpose. Accounts and reports of the results of such compositional changes are sparse, however, and the present commercial alloys do not include any of these additional constituents.
The literature in this field, however, contains little concerning efforts to improve upon the mechanical strength of zirconium-base alloys and particularly the load-carrying capacity of fuel cladding and other reactor parts subjected to prolonged exposure to typical boiling water reactor conditions. This is in spite of the fact that it has long been general knowledge that slow strain rate ductility of these alloys is lost to a great extent as a result of radiation exposure over periods of a year or more. The problem of premature termination of service life because of fast neutron radiation-induced embrittlement is particularly aggravated in the case of nuclear fuel containment channels and tubes or cladding. The natural swelling of the fuel as it is burned produces high localized stresses leading to stress-corrosion cracking of the cladding at a time before corrosion of the type described in the above patents might normally necessitate cladding replacement.
THE INVENTION
This invention, which is predicated on my discovery and new concept to be described, provides an answer to both the iodine stress-corrosion problem and the embrittlement problem in the form of a process which can result in doubling the length of the service life of zirconium-base alloy nuclear fuel cladding. Moreover, this result is obtained without incurring any significant offsetting cost or performance disadvantage.
My discovery is that a zirconium-base alloy of the kind presently used in nuclear reactors will have a much greater load-carrying capacity after being subjected to fast neutron radiation for a period of a year or so if it contains from 0.5 to 0.25 percent beryllium. More specifically, such an alloy will characteristically exhibit 500 to 600 percent greater load-carrying capacity (i.e., uniform strain to maximum load) than conventional beryllium-free cladding and can therefore be expected to serve in that use and environment much longer and possibly twice as long as the zirconium-base alloys in general use in nuclear reactors.
My new concept is to prepare a zirconium-base alloy containing 0.05 to 0.25 percent beryllium for use as nuclear fuel cladding by heating to a temperature of the order of 900° C. and then water-quenching it. Although such heat treatment results in a phase transformation, the zirconium alloy transforming in part or totally from the alpha to the beta phase, and the prior art warns that detrimental effects on mechanical properties will result, I have found that there are substantial advantages to be gained by effecting such transformation. For one thing, ductility is enhanced materially, as will subsequently be described in more detail. For another, resistance to corrosion under boiling water nuclear reactor conditions resulting in heavy oxide coating formation on fuel cladding may thereby be substantially reduced or limited, as set forth more fully and generically claimed in copending patent application Ser. No. 552,794, filed Feb. 25, 1975, abandoned in favor of Ser. No. 852,906, filed Nov. 18, 1977.
In its method aspect, this invention in brief description includes the steps of forming a zirconium-base alloy body containing 0.05 to 0.25 percent beryllium, heating the body to a temperature above 900° C. and then quenching, and finally subjecting the body to boiling water reactor conditions for a long period of time such as a year or more. More specifically, the alloy body will be of at least 95percent zirconium, the quenching will be done with water and the nuclear reactor conditions will be a temperature of about 325° C. and a fast-neutron flux of 1.0 to 10.0×10 21 nvt.
In its product or article aspect, this invention takes the form of a zirconium-base alloy body of substantially greater load-carrying capacity than similar conventional bodies of the alloy irradiated in the same way and to the same extent and having at 325° C. an unique combination of physical properties including 2.5 percent uniform elongation, 8.2 percent total elongation and 35 percent area reduction, yield strength greater than 76,000 psi, and tensile strength greater than 80,000 psi. In more specific terms, the body is a nuclear fuel container for use in a nuclear reactor, and is in the form of a tube having microstructure in which the intermetallic phase is to some extent segregated at the grain boundaries as a consequence of the heat treatment and quenching steps stated above. Additionally, the fuel container or cladding is irradiated as a result of having been subjected for a long period to fast-neutron flux and has greater load-carrying capacity than a counterpart fuel container similarly irradiated but containing no berrylium.
DESCRIPTION OF THE DRAWINGS
FIG. 1 presents a partial cutaway sectional view of a nuclear fuel assembly containing nuclear fuel elements constructed according to the teaching of this invention;
FIG. 2 is a chart bearing curves illustrating physical property data obtained in tests of the new product of this invention and the corresponding prior art product, and
FIG. 3 is another chart on which stress is plotted against strain and the curves illustrate data taken in tests performed under an iodine atmosphere.
DETAILED DESCRIPTION OF THE INVENTION
As indicated by FIG. 1, a primary application of the present invention is for the fabrication of nuclear fuel assemblies such as that illustrated at 10 consisting of a tubular flow channel 11 of generally square cross section provided at its upper end with lifting bale 12 and at its lower end with a nose piece (not shown due to the lower portion of assembly 10 being omitted). The upper end of channel 11 is open at 13 and the lower end of the nose piece is provided with coolant flow openings. An array of fuel elements or rods 14 is enclosed in channel 11 and supported therein by means of upper end plate 15 and a lower end plate (not shown due to the lower portion being omitted). The liquid coolant ordinarily enters through the openings in the lower end of the nose piece, passes upwardly around fuel elements 14, and discharges at upper outlet 13 in a partially vaporized condition for boiling water reactors or in an unvaporized condition for pressurized reactors at an elevated temperature.
The nuclear fuel elements or rods 14 are sealed at their ends by means of end plugs 18 welded to the cladding 17, which may include studs 19 to facilitate the mounting of the fuel rod in the assembly. A void space or plenum 20 is provided at one end of the element to permit longitudinal expansion of the fuel material and accumulation of gases released from the fuel material. A nuclear fuel material retainer means 24 in the form of a helical member is positioned within space 20 to provide restraint against the axial movement of the pellet column, especially during handling and transportation of the fuel element.
The fuel element is designed to provide an excellent thermal contact between the cladding and the fuel material, a minimum of parasitic neutron absorption, and resistance to bowing and vibration which is occasionally caused by flow of the coolant at high velocity.
Cladding 17 is produced in accordance with this invention by a process which includes in addition to the usual tube-forming operations a heat treatment in argon or other inert atmosphere above the alpha-alpha plus beta transformation temperature followed by a water quench. The rate at which the work piece is heated up to the transformation temperature range is a matter of choice, but the time it is maintained in that range is preferably about 30 seconds and the cooling rate down to 700° to 750° C. may be as low as 50° C. per second. As so treated, the zirconium alloy body is made more easily workable and forming operations are facilitated through the warm-working stage. It also appears, as indicated above, that the physical properties and particularly the ductility of the ultimate cladding product may be considerably enhanced in this manner. As a further advantage, depending upon the nature of the finishing operations involved in producing the cladding, the tendency toward corrosion may be to a large extent suppressed as a consequence of the heat treatment above the alpha-alpha plus beta transformation temperature of about 810° C. This latter effect would be attributable, possibly, to the segregation of the intermetallic phase at the grain boundaries, as set out in the aforesaid copending application, Ser. No. 552,794. In any event, the zirconium alloy employed in this process is one which contains beryllium in amount from 0.05 to 0.25 weight percent, and preferably also contains about 1.5 weight percent tin and 0.05 weight percent nickel, and at least 95 weight percent zirconium. In other words, it is preferably either Zircaloy-2 or Zircaloy-4.
The method and products of this invention are set forth in more detail together with actual test results in the following illustrative example in which Zircaloy-2 was used, being melted in an electric arc furnace under vacuum to provide control specimens as well as test specimens meeting the special compositional requirements of this invention.
EXAMPLE
Of the total of seven test specimens, four were of commercial Zircaloy-2 composition and the others differed therefrom only in that they each contained 0.2 weight percent beryllium. These specimens in the form of cast buttons about 2.5 inches in diameter and about one-half inch thick were machined to provide a smooth surface and then wrapped in zirconium foil, offset-forged approximately 30 percent, heated to 930° C. in argon and then again offset-forged. They were sandblasted and wrapped again in zirconium foil and reheated to 930° C. for 20 minutes and water-quenched. The four specimens (Nos. 1, 3, 4 and 5 in Table I below) containing no beryllium were then rolled to ultimate thickness of one-sixteenth inch by a multiple pass method, the final passes being cold-rolling operations. These sheets were sandblasted, pickled in aqueous 2.0 percent HF and 6.0 percent HNO 3 , and then Specimens 1 and 3 were finally annealed at 650° C. for one hour while Specimens 4 and 5 were annealed at 580° C. for four hours. Beryllium-containing Specimens 2, 6 and 7 were processed in the same manner as Specimens 4 and 5 through the final annealing stage. Specimens 1 and 2 were maintained at 327° C. (620° F.) in a neutral atmosphere for one year, and Specimens 3, 4, 5, 6 and 7 were exposed to fast-neutron radiation at temperatures of either 250° C. or 327° C. for the same twelve-month period, being located within standard-size fuel cladding dummy fuel rods installed in fuel bundles in a working boiling water reactor core. Flux wires of nickel and iron indicated that these specimens were subjected to radiation exposure, peaking at 3.1×10 21 nvt for corresponding peak fast flux values of 7×10 13 n/cm 2 -sec. Thus, the typical specimen of this series was exposed to the fast flux over a period of one to 11/2 years in a neutral or an inert helium atmosphere at the temperature indicated in Table I.
The results of all of the tests made on these irradiated and unirradiated specimens are set out in Table I:
TABLE I__________________________________________________________________________Neutron Test Yield TensileFluence Temp, Oxygen Strength Strength, Uniform Total ReductionSpecimen10.sup.21 °C. ppm wt (0.2%) psi psi Elong, % Elong, % of area, %__________________________________________________________________________1 -- 327 1500 22,400 28,400 16.4 30.6 79.92 -- 327 1200 27,100 37,600 16.0 27.8 56.83 1.5 327 1500 73,800 75,200 0.35 5.9 424 1.5 250 920 56,500 56,700 0.45 8.0 445 1.4 250 1600 74,600 76,000 0.80 9.3 536 1.2 250 1200 78,600 84,800 3.30 8.6 377 1.2 327 1200 76,800 81,200 2.50 8.2 35__________________________________________________________________________
The test temperature stated in Table I is the temperature at which the mechanical properties of the specimen were tested in each instance, all these specimens being subjected to the same 327° C. temperature environment over the twelve-month period under the conditions as set forth above.
The effect of the beryllium addition is demonstrated in FIG. 2 where the dramatic difference in load-carrying capacity between Specimens 3 and 7 is indicated by Curves A and B, respectively. Also, it will be noted in this connection that in Table I the same inherent characteristic is reflected in the uniform strain-to-maximum-load which increased from 0.35 percent in Specimen 3 to 2.5 percent in Specimen 7, a net increase over 600 percent. The tests yielding these data were conducted at a strain rate of 8.3×10 -4 cm/cm/sec. Metallographic examination of these two specimens revealed that deformation was noticeably more diffuse in Specimen 7 than in Specimen 3.
The effect of the beryllium addition is further illustrated in FIG. 3 where, again, there is a dramatic difference in strength between Specimens 3 and 7 as indicated by Curves C and D, respectively. As previously noted, the tests resulting in the data represented by these curves were conducted in an aggressive environment (i.e., under an iodine atmosphere) at a strain rate of 2.83×10 -6 cm/cm/sec.
The iodine atmosphere tests were conducted by subjecting the work piece at 325° C. in each case to an atmosphere of helium gas containing iodine in amount approximating the room temperature iodine partial pressure. Thus, helium gas is flowed continuously through an iodine crystal bed from which it entered the test chamber. Helium gas flow through the chamber was continuous as the pressure within the chamber was maintained slightly greater than atmospheric pressure. | A fast neutron-irradiated zirconium-base alloy body having load-carrying capacity substantially greater than similar conventional zirconium-base alloy bodies likewise irradiated is produced by subjecting a body heat treated at 930deg C. And then water-quenched and containing 0.2 weight percent beryllium and at least 95 weight percent zirconium to integrated neutron flux approximating 1.2x10 21 nvt while maintaining the body at about 330deg C. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Application is a continuation-in-part of U.S. application Ser. No. 12/329,349 tided “Self-Identifying Power Source For Use In Recharging Vehicles Equipped With Electrically Powered Propulsion Systems” filed 5 Dec. 2008, and U.S. application Ser. No. 12/329,368 titled “System For On-Board Metering Of Recharging Energy Consumption In Vehicles Equipped With Electrically Powered Propulsion Systems” filed 5 Dec. 2008, and U.S. application Ser. No. 12/329,389 titled “Network For Authentication, Authorization, And Accounting Of Recharging Processes For Vehicles Equipped With Electrically Powered Propulsion Systems” filed 5 Dec. 2008. In addition, this Application is related to a US Application titled “Intra-Vehicle Charging System For Use In Recharging Vehicles Equipped With Electrically Powered Propulsion Systems”, US Application tided “Dynamic Load Management For Use In Recharging Vehicles Equipped With Electrically Powered Propulsion Systems”, and US Application titled “Centralized Load Management For Use In Recharging Vehicles Equipped With Electrically Powered Propulsion Systems”, all filed on the same date as the present application and incorporating the disclosures of each herein.
FIELD OF THE INVENTION
[0002] This invention relates to a system for delivering power via a plurality of sub-networks for use in recharging vehicles equipped with electrically powered propulsion systems, where the Electric Grid interconnect used in each sub-network provides a unique power source identification to the vehicle for energy consumption billing purposes.
BACKGROUND OF THE INVENTION
[0003] It is a problem in the field of recharging systems for vehicles equipped with electrically powered propulsion systems to bill the vehicle operator for the energy consumption where the Electric Grid is used as the source of power to charge the vehicular battery banks. Presently, each outlet that is served by a local utility company is connected to the Electric Grid by an electric meter which measures the energy consumption of the loads that are connected to the outlet. The utility company bills the owner of the premises at which the outlet is installed for the total energy consumption for a predetermined time interval, typically monthly. Recharging a vehicle which is equipped with an electrically powered propulsion system results in the premises owner errantly being billed for the recharging and the vehicle owner not being billed at all. An exception to this scenario is where the premises owner is paid a flat fee by the vehicle owner for the use of the outlet to recharge the vehicular battery banks.
[0004] Electric transportation modes typically take the form of either a pure battery solution, where the battery powers an electric propulsion system, or a hybrid solution, where a fossil fuel powered engine supplements the vehicle's battery bank to either charge the electric propulsion system or directly drive the vehicle. Presently, there is no electricity refueling paradigm, where a vehicle can plug into the “Electric Grid” while parked at a given destination and then recharge with sufficient energy stored in the vehicular battery banks to make the trip home or to the next destination. More to the point, the present “grid paradigm” is always “grid-centric”; that is, the measurement and billing for the sourced electricity is always done on the grid's supply side by the utility itself. One example of a system that represents this philosophy is the municipal parking meter apparatus where an electric meter and credit card reader is installed at every parking meter along a city's streets to directly bill vehicle owners for recharging their vehicular battery banks. Not only is this system very expensive to implement, but it remains highly centralized and is certainly not ubiquitous. This example solution and other analogous grid-centric solutions are not possible without an incredible capital expenditure for new infrastructure and an extensive build time to provide widespread recharging capability.
[0005] Thus, the problems with centralized vehicular charging are:
infrastructure cost, lack of ubiquity in the infrastructure's extent, extensive time to deploy a nationwide system, can't manage/control access to electricity without a per outlet meter, no ubiquity of billing for downloaded electricity, no method to assure a given utility is properly paid, no method to provide revenue sharing business models, no methods to manage and prevent fraud, incapable of instantaneous load management during peak loads, incapable of load management on a block by block, sector by sector load, or city-wide basis, and incapable of billing the energy “downloaded” to a given vehicle, where a given vehicle is random in its extent, and where the vehicle is plugged into the grid is also random in its extent.
[0017] What is needed is a solution that can be deployed today, that doesn't require a whole new infrastructure to be constructed, is ubiquitous in its extent, and that uses modern communications solutions to manage and oversee the next generation electric vehicle charging grid.
[0018] The above-noted patent applications (U.S. application Ser. No. 12/329,349 titled “Self-Identifying Power Source For Use In Recharging Vehicles Equipped With Electrically Powered Propulsion Systems” filed 5 Dec. 2008, and U.S. application Ser. No. 12/329,368 titled “System For On-Board Metering Of Recharging Energy Consumption In Vehicles Equipped With Electrically Powered Propulsion Systems” filed 5 Dec. 2008, and U.S. application Ser. No. 12/329,389 titled “Network For Authentication, Authorization, And Accounting Of Recharging Processes For Vehicles Equipped With Electrically Powered Propulsion Systems” filed 5 Dec. 2008) collectively describe an E-Grid concept for use in providing power to vehicles which include a propulsion system powered, at least in part, by electric power, at least some of which is stored onboard the vehicle in an electric power storage apparatus.
[0019] A key element of the conceptual “Charging-Grid” solution presented herein is not unlike the problem faced by early cellular telephone operators and subscribers. When a cellular subscriber “roamed” out of their home “network”, they couldn't make phone calls, or making phone calls was either extremely cumbersome or expensive or both. The present E-Grid Sub-Network Load Manager is a part of an “E-Grid” billing structure, which includes full AAA functionality—Authentication, Authorization, and Accounting. For the early historical cellular paradigm, the cellular architecture used a centralized billing organization that managed the “roaming” cellular customer. In a like fashion, the E-Grid proposed herein has a centralized billing structure that manages the “roaming” vehicle as it “self-charges” at virtually any power source/electric outlet in a seamless yet ubiquitous manner anywhere a given utility is connected to the “E-Grid architecture”.
[0020] A second component of the E-Grid is to place the “electric meter” in the vehicle itself to eliminate the need to modify the Electric Grid. The Self-Identifying Power Source provides the vehicle's electric meter with a unique identification of the power source to enable the vehicle to report both the vehicle's energy consumption and the point at which the energy consumption occurred to the utility company via the ubiquitous communications network.
[0021] An advantage of this architecture is that the vehicle is in communication with the utility company, which can implement highly dynamic load management, where any number of vehicles can be “disconnected” and “re-connected” to the Electric Grid to easily manage peak load problems for geographic areas as small as a city block or as large as an entire city or even a regional area.
[0022] The innovative “E-Grid” architecture enables a vehicle to plug in anywhere, “self-charge”, and be billed in a seamless fashion, regardless of the utility, regardless of the vehicle, regardless of the location, regardless of the time. The utility for that given downloaded charge receives credit for the electricity “downloaded” across their network, whether that customer is a “home” customer or a “roaming” customer. The “owner” of the electrical outlet receives credit for the power consumed from their “electrical outlet”. In addition, if a given customer has not paid their E-Grid bill, the system can directly manage access to the grid to include rejecting the ability to charge or only allowing a certain charge level to enable someone to get home. The E-Grid architecture can have account managed billing, pre-paid billing, and post-paid billing paradigms. The billing is across any number of electric utility grids, and the E-Grid architecture is completely agnostic to how many utility suppliers there are or where they are located. So too, the E-grid architecture is agnostic to the charging location, where said charging location does not require a meter and does not require telecommunications capability.
[0023] The compelling societal benefit of the novel E-Grid architecture is that it is possible to deploy it today, without a major change in current infrastructure or requiring adding new infrastructure. Virtually every electrical outlet, no matter where it may be located, can be used to charge a vehicle, with the bill for that charge going directly to the given consumer, with the owner of the electrical outlet getting a corresponding credit, with the payment for electricity going directly to the utility that provided the energy—all in a seamless fashion.
[0024] One problem faced by the E-Grid is that typically a number of vehicles arrive at a destination in close temporal proximity, connect to the power sources served by a service disconnect, and concurrently request service. Once their batteries are charged, there is no load placed on the service disconnect until these vehicles depart and other vehicles arrive to be recharged. Given this high demand scenario, a single service disconnect can serve only a limited number of vehicles at a time if they concurrently demand the delivery of power. This is a peak load issue, where the existing service disconnect is unable to manage a plurality of concurrently received requests for service and, therefore, is limited in the number of vehicles that can be served.
BRIEF SUMMARY OF THE INVENTION
[0025] The above-described problems are solved and a technical advance achieved by the present Sub-Network Load Management For Use In Recharging Vehicles Equipped With Electrically Powered Propulsion Systems (termed “E-Grid Sub-Network Load Manager” herein) which manages a plurality of power sources to which the vehicles are connected to manage delivery of the power consumed by the recharging of the vehicular battery banks.
[0026] The E-Grid typically is implemented via the use of a plurality of utility interfaces, each of which includes an electric meter which is installed at a utility customer's facilities and an associated service disconnect. The term “service disconnect” as used herein can be a main service disconnect which serves a plurality of Self-Identifying Power Sources as described herein, or a main service disconnect which serves a plurality of circuit breakers, each of which serves a plurality of the Self-Identifying Power Sources. The present E-Grid Sub-Network Load Manager is applicable to both architectures and is used to regulate the demand for power as concurrently presented by a plurality of vehicles which are connected to a Sub-Network of the E-Grid, where the sub-network can be either the plurality of Self-Identifying Power Sources served by the single service disconnect noted above or each sub-set comprising the plurality of Self-Identifying Power Sources served by each of the circuit breakers connected to a single service disconnect. In the multiple circuit breaker architecture, the E-Grid Sub-Network Load Manager can operate on a hierarchical basis, regulating not only the loads presented to each circuit breaker, but also to the service disconnect, since it is standard practice in electrical installations to have the sum of the current handling capacities of the circuit breakers exceed the current handling capacity of the associated service disconnect.
[0027] Thus, the E-Grid Sub-Network Load Manager operates to regulate the demands presented by the vehicles to the associated Sub-Network thereby to spread the load presented to the service disconnect over time to enable the controllable charging of a large number of vehicles. The load management can be implemented by a number of methodologies, including: queuing the requests and serving each request in sequence until satisfaction, queuing the requests and cycling through the requests, partially serving each one, then proceeding to the next until the cyclic partial charging service has satisfied all of the requests, ordering the requests pursuant to a percentage of recharge required measurement, ordering the requests on an estimated connection time metric, ordering the requests on a predetermined level of service basis, and the like. It is evident that a number of these methods can be concurrently employed thereby to serve all of the vehicles in the most efficient manner that can be determined.
[0028] The implementation of the E-Grid Sub-Network Load Manager can include intelligent Self-Identifying Power Sources which can be controlled to deliver power on a basis determined by the E-Grid Sub-Network Load Manager and/or the use of intelligent Self-Metering Vehicles which can be controlled to request power on a basis determined by the E-Grid Sub-Network Load Manager or combinations of both. In addition, the availability of information from the Self-Metering Vehicles relating to power required to recharge, recharge current handling capacity, estimated time of connection, and class of service for which the vehicle owner has contracted all enhance the operation of the E-Grid Sub-Network Load Manager.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 illustrates, in block diagram form, the E-Grid network architecture, including interconnected communication networks with a unified authentication, authorization, and accounting structure;
[0030] FIG. 2 illustrates, in block diagram form, a more detailed embodiment of the E-Grid network architecture shown in FIG. 1 which discloses multiple utility companies;
[0031] FIG. 3 illustrates, in flow diagram form, the operation of the billing system for the E-Grid system;
[0032] FIG. 4 illustrates, in block diagram form, the Charging, Control, and Communicator (CCC) module installed in a vehicle;
[0033] FIG. 5 illustrates, in block diagram form, a detailed block diagram of the CCC module;
[0034] FIG. 6 illustrates an embodiment of the Self-Identifying Power Source for use in the E-Grid system;
[0035] FIG. 7 illustrates, in block diagram form, the communications interconnections in use in the E-Grid network;
[0036] FIG. 8 illustrates, in block diagram form, the architecture of a typical E-Grid application of the E-Grid Sub-Network Load Manager, where an electric utility meter and its associated main service disconnect serve a plurality of circuit breakers, each of which serves a plurality of the Self-Identifying Power Sources;
[0037] FIGS. 9A and 9B illustrate, in flow diagram form, the operation of the present E-Grid Sub-Network Load Manager; and
[0038] FIG. 10 illustrates, in flow diagram form, operation of a typical intra-vehicle power exchange management process.
DETAILED DESCRIPTION OF THE INVENTION
[0039] FIG. 1 illustrates, in block diagram form, the E-Grid network architecture, including interconnected communications networks with a unified authentication, authorization, and accounting structure; while FIG. 2 illustrates, in block diagram form, a more detailed embodiment of the E-Grid network architecture shown in FIG. 1 . In the following description, the term “Vehicle” is used, and this term represents any mechanism which includes a propulsion system powered, at least in part, by electric power, at least some of which is stored onboard the vehicle in an electric power storage apparatus, as well as any electric power consuming loads incorporated into, transported by, or associated with any type of vehicle, whether or not these types of vehicles are electrically powered.
Traditional Electric Grid
[0040] Electric Grid 160 shown in FIG. 1 represents the source of electric power, as provided by multiple utility companies which serve a wide geographic area. For the purpose of illustration, the present description focuses on a single utility company 155 which serves a particular geographic area (service area) and provides electric power to a multitude of customers via a utility interface 114 which typically comprises an electric meter which is installed at the customer's facilities 116 and an associated service disconnect. Nothing herein limits the physical elements contained within utility interface 114 to include that an electric meter may not be a part of utility interface 114 in certain applications.
[0041] The electric meter in utility interface 114 serves to measure the energy consumption by the various outlet connected loads, such as Vehicles 101 , 102 and fixed loads (not shown) which are connected to the customer's electric meter via a customer's service disconnect (circuit breaker panel), which is part of the utility interface 114 for the purpose of this description. These elements represent the existing electric power delivery infrastructure. The arrow shown at the bottom of FIG. 1 highlights the fact that the connection to Electric Grid 160 is bidirectional in that electric power traditionally flows from the Electric Grid 160 to the utility interface 114 and thence to the customer's loads—Vehicles 101 , 102 —but also can flow in the reverse direction, from the vehicular battery banks of Vehicles 101 , 102 , through the utility interface 114 to the Electric Grid 160 ; and these conductors also can carry Power Line Carrier (PLC) communications, such as data which identifies electrical outlet 111 , via plug 171 to Vehicle 101 . The PLC communication network could also be used as an alternate communication pathway to the Utility Service Center 100 for Authentication, Authorization, and Accounting functionality.
Utility Service Center
[0042] Communication Network 150 is the preferred communication medium which enables the Vehicles 101 , 102 to communicate with Utility Service Center 100 to implement the Vehicle registration and billing processes of Control Processor 140 via Grid Home Location Register (GHLR) 120 and Grid Visitor Location Register (GVLR) 130 . The Communication Network 150 comprises any technology: cellular, WiFi, wired Public Switched Telephone Network (PSTN), Internet, etc. The Grid Home Location Register 120 and Grid Visitor Location Register 130 are further connected to the Authentication, Authorization, and Accounting System 110 (AAA System 110 ). The communication mode for the Vehicles 101 , 102 can be wireless, wired (such as via Communication Network 150 ), or via the Electric Grid 160 using Power Line Carrier communication as previously mentioned. For the purpose of illustration, a wireless link to the Communication Network 150 is used in this embodiment, although the other modes can be used.
[0043] The Vehicles 101 , 102 first communicate with Communication Network 150 in well-known fashion to link to Utility Service Center 100 where the Control Processor 140 accesses the Location Registers 120 and 130 . These devices contain the user profile for the account holder, including the identification of the home utility company, billing account, and maximum authorized credit, where the user is authorized to charge, identification of any value added services that the user subscribes to, and the like. When registering with the Utility Service Center 100 , the Vehicles 101 , 102 first seek to register with the Grid Home Location Register 120 if in their home territory (i.e., within the territory served by their residence's electric utility provider). If Vehicle 101 is traveling outside of its home territory, it would first register with the serving utility's Grid Visitor Location Register 130 which would then communicate with the user's Grid Home Location Register 120 to confirm that the user is a “real” customer, and all of the data stored in the Grid Home Location Register 120 about a particular customer is copied to the Grid Visitor Location Register 130 while the Vehicle 101 is in the “roaming” territory. Communications via network 1 (typically via wireless means) would let the Vehicles 101 , 102 know whether they are in the home territory or whether they are roaming (not unlike how cellular phone networks operate today). After successful registration, the AAA System 110 begins to manage the charging transaction.
[0044] At AAA System 110 , a number of essential functions occur. All Vehicles seeking to receive electrical power from Electric Grid 160 to charge the vehicular battery banks (also termed “electric energy storage apparatus”) are first authenticated, then authorized, and billed for the energy consumed via the charging process. The term “Authentication” means that a device is valid and permitted to access the Electric Grid 160 (the authorization phase of AAA). AAA System 110 also manages the accounting process, ensuring that all bills go to the correct vehicle owner, the electric utility gets paid for the electricity that it supplied, and the owner of utility interface 114 is credited with the electricity that flowed through utility interface 114 to recharge the vehicular battery banks. There could also be revenue share models where a facility owner could get a portion of the overall revenue for providing physical access (i.e., an electrical plug-in location). AAA System 110 is seen as a more central device, to be shared among a number of electric utilities, although there is nothing from preventing each utility having its own AAA System.
Multi-Utility Embodiment
[0045] FIG. 1 is, in reality, a multidimensional network in which N electric utilities are served by M Electric Grids with corresponding communication networks, as shown in FIG. 2 .
[0046] Electric Grids 240 , 250 shown in FIG. 2 represent the source of electric power, as provided by multiple utility companies which serve a wide geographic area and provide electric power to a multitude of customers via utility interfaces 281 - 285 . The utility interfaces 281 - 285 serve to measure the energy consumption by the various outlet connected loads, such as Vehicles 291 - 295 . These elements represent the existing, present day electric power delivery infrastructure as described above. Electric power traditionally flows from the Electric Grid 240 , 250 to the utility interfaces 281 - 285 and thence to the customer's loads—Vehicles 291 - 295 via plug 271 - 275 -outlet 261 - 265 combinations, but power also can flow in the reverse direction, from the vehicular battery banks of Vehicles 291 - 295 , through the utility interfaces 281 - 285 to the Electric Grids 240 , 250 .
[0047] Communication Networks 220 , 230 are the communication mediums which enable the Vehicles 291 - 295 to communicate with Utility Service Center 200 which, as noted above, implements the vehicle registration process via Grid Home Location Register (GHLR) 260 and Grid Visitor Location Register (GVLR) 270 . The Grid Home Location Register 260 and Grid Visitor Location Register 270 are further connected to the Authentication, Authorization, and Accounting System 280 (AAA System 280 ). The communication mode for the Vehicles 291 - 295 can be wireless, wired, or via the Electric Grid, as previously discussed. For the purpose of illustration, a wireless link to the Communication Networks 220 , 230 is used in this embodiment, although the other communication modes can be used.
Self-Identifying Power Source
[0048] FIG. 6 illustrates an embodiment of the present Self-Identifying Power Source 116 for use in the E-Grid system. The Self-Identifying Power Source 116 can be implemented in a variety of ways, and FIG. 6 illustrates the components that can be used to produce and transmit a unique identification of the power source to a vehicle for energy consumption credit and billing purposes. As noted above, it is a problem in the field of recharging systems for vehicles equipped with electrically powered propulsion systems to bill the vehicle operator or the financially responsible party for the energy consumption where the Electric Grid is used as the source of power to charge the vehicular battery banks. Presently, each outlet (or jack or inductive power source) that is served by a local utility company is connected to the Electric Grid by a utility meter which measures the energy consumption of the loads that are connected to the outlet. The utility company bills the owner of the premises at which the outlet is installed for the total energy consumption for a predetermined time interval, typically monthly.
[0049] The solution to this problem is to have the vehicle self-meter its energy consumption in recharging the vehicular battery banks and report the energy consumption to the utility company that serves the power source to which the vehicle is connected. The utility company then can bill the vehicle owner and simultaneously credit the power source for this consumption. In implementing this paradigm, the power source identification can be implemented at various layers of the power distribution network. The outlet 111 to which the Vehicle 101 connects can identify itself, the utility interface 114 (such as a utility meter) can identify itself, or the premises at which the outlet 111 and the utility interface 114 (in this example a meter 614 ) are installed and physically located can be identified. All of these scenarios are effective to enable the utility company to credit the owner of the power source with the power consumed by Vehicle 101 .
Power Source Identification—Outlet Level
[0050] A first implementation of the power source identification is at the outlet level, where the self-identifying element comprises an electrical outlet 111 having a housing into which are molded a plurality of conductors that function to conduct the electricity from the electric meter 614 (and associated circuit protection devices) to a plug 171 from the Vehicle 101 which is inserted into the outlet 111 of the Self-Identifying Power Source 116 . There are numerous outlet conductor configurations which are specified by regulatory agencies, such as the National Electric Manufacturers Association (NEMA), for various voltages and current capacities; and a typical implementation could be a 2-pole 3-wire grounding outlet to reduce the possibility that the plug which is connected to the vehicle would be inadvertently disconnected from the Self-Identifying Power Source 116 .
[0051] The Self-Identifying Outlet 610 of the Self-Identifying Power Source 116 includes an outlet identification device 612 which transmits outlet identification data to the Vehicle 101 . This outlet identification data represents a unique code which identifies this particular Self-Identifying Outlet 610 of the Self-Identifying Power Source 116 in order for the owner of the associated electric meter 614 to receive credit for the energy consumption associated with the present vehicle battery recharging process. This outlet identification data can be transmitted over the power conductors or can be transmitted wirelessly to the vehicle by the outlet identification device 612 , or may constitute an RFID solution where the vehicle reads the RFID code embedded in RFID device 613 located in the Self-Identifying Outlet 610 of the Self-Identifying Power Source 116 . In addition to the unique identification of the Self-Identifying Outlet 610 of the Self-Identifying Power Source 116 , the data can indicate the mode of data transmission appropriate for this locale. Thus, the vehicle may be instructed via this locale data to wirelessly transmit the accumulated energy consumption data to a local premises server for accumulation and forwarding to the utility company, or wirelessly via a public Communication Network 150 directly to the utility company, or via the power conductors 163 to a communications module associated with the electric meter 614 , or to the utility company 155 via the Electric Grid 160 .
[0052] In operation, every time a mating plug is inserted into the outlet 111 of the Self-Identifying Power Source 116 or the Vehicle 101 “pings” the Self-Identifying Outlet 610 , the outlet identification device 612 outputs the unique outlet identification data or RFID Device 613 provides a passive identification read capability to enable the Vehicle 101 to uniquely identify the Self-Identifying Outlet 610 of the Self-Identifying Power Source 116 .
[0053] In addition, a power switch 611 optionally can be provided to enable the utility company 155 to disable the provision of power to Vehicle 101 pursuant to the authorization process described below. Switch 611 can be activated via a power line communications session with the utility company 155 via the Electric Grid 160 . Alternatively, this switch could be “virtual” and located in the vehicle itself where the vehicle does not permit charging to occur even though the outlet 111 may be “hot” or have power to it.
Power Source Identification—Electric Grid Interconnect Level
[0054] A second implementation of the power source identification is at the Electric Grid interconnect 620 level, where the self-identifying element comprises one or more identification devices associated with the electric meter 614 . Since each premises is equipped with an electric meter 614 required by the utility company and one or more disconnect devices 622 to serve one or more outlets 610 , the identification of a utility meter as the Electric Grid interconnect is sufficient data to enable the utility company to credit the premises owner with the power consumed by Vehicle 101 . Since the Vehicle 101 self-meters, for billing purposes it is irrelevant which outlet 111 serves to provide power to the Vehicle 101 . The energy consumption session, as described in more detail below, is not dependent on the exact physical connection of Vehicle 101 to an outlet 111 , but can be managed at the power grid interconnection 620 level.
[0055] Thus, meter identification device 621 transmits meter identification data to the Vehicle 101 . This meter identification data represents a unique code which identifies this particular electric meter 614 of the Self-Identifying Power Source 116 in order for the owner of the associated electric meter 614 to receive credit for the energy consumption associated with the present vehicle battery recharging process. This meter identification data can be transmitted over the power conductors or can be transmitted wirelessly to the vehicle by the meter identification device 621 , or may constitute an RFID solution where the vehicle reads the RFID code embedded in RFID device 623 located in the power grid interconnect 620 of the Self-Identifying Power Source 116 . In addition to the unique identification of the power grid interconnect 620 of the Self-Identifying Power Source 116 , the data can indicate the mode of data transmission appropriate for this locale. Thus, the vehicle may be instructed via this locale data to wirelessly transmit the accumulated energy consumption data to a local premises server for accumulation and forwarding to the utility company, or wirelessly via a public Communication Network 150 directly to the utility company, or via the power conductors 163 to a communications module associated with the electric meter 614 , or to the utility company 155 via the Electric Grid 160 .
Power Source Identification—Premises Level
[0056] The recharging process to include billing and crediting is not necessarily dependent on meter 614 shown in FIG. 6 . For example, a third embodiment involves an intelligent identification communication architecture communicated via Power Line Carrier (PLC) communication from Utility Company 155 to Electric Grid 160 which ultimately arrives at each and every outlet in the universe of the Electric Grid 160 . This intelligent Outlet ID is communicated directly to outlet 111 (not shown directly on FIG. 6 ) wherein each outlet has a unique ID as identified and managed by the Utility 155 . This Power Line Carrier ID communication goes directly from Utility Company 155 to Electric Grid 160 via Utility Interface 114 to Vehicle 101 to PLC Communication Module 560 (shown in FIG. 5 ).
[0057] A fourth implementation of the power source identification is at the premises level, where the self-identifying element comprises one or more identification devices (such as RFID device 633 ) associated with the physical premises served by one or more power grid interconnects 620 . Since a plurality of electric meters 614 can be used to serve a plurality of outlets 111 located at a physical premises, the granularity of identifying the owner of the premises is sufficient to implement the energy consumption credit process as described herein. Thus, Vehicle 101 can sense an RFID device 633 upon entry into the premises at which the outlet 111 is located and use the RFID data, as described above, as the utility company customer identification, since Vehicle 101 self-meters its energy consumption.
Vehicle Infrastructure
[0058] FIG. 4 illustrates, in block diagram form, the Charging, Control, and Communicator (CCC) module 410 installed in a vehicle; and FIG. 5 illustrates, in block diagram form, a detailed block diagram of the CCC module 410 . Vehicle 101 is equipped with an electrically powered propulsion system and vehicular battery banks 420 (or any such device that can store electrical energy). Presently, each outlet that is served by a local utility company is connected to the Electric Grid 160 by a utility meter 614 housed in Utility Interface 114 which measures the energy consumption of the loads that are connected to the outlet. The utility company bills the owner of the premises at which the outlet is installed for the total energy consumption for a predetermined time interval, typically monthly. Recharging a vehicle which is equipped with an electrically powered propulsion system results in the premises owner being billed for the recharging and the vehicle owner not being billed.
[0059] The present paradigm is to place the “electric meter” in the vehicle itself to eliminate the need to modify the Electric Grid. As shown in FIG. 6 , the present Self-Identifying Power Source 116 provides the vehicle's electric meter with a unique identification of the outlet 111 to enable the vehicle to report both the vehicle's energy consumption and the point at which the energy consumption occurred to the utility company via the ubiquitous communications network. The consumption can be reported for each instance of connection to the Electric Grid or the Vehicle can “accumulate” the measure of each energy consumption session, then periodically transmit energy consumption information along with the associated unique outlet identification data to the power company or a third party billing agency via the communication network. Alternatively, transmission of these signals to the power company via power lines is a possibility (Power Line Carrier). Another mode of billing is for the vehicle to be equipped with a usage credit accumulator which is debited as power is consumed to charge the vehicle's battery. The credit accumulator is replenished as needed at predetermined sites or via WiFi/Cellular or via Power Line Carrier.
[0060] The Charging, Control, and Communicator (CCC) module 410 is shown in additional detail in FIG. 5 . The Vehicle 101 is equipped with either an inductive coupler (not shown) or a plug 171 to enable receipt of electric power from the Self-Identifying Power Source 116 . Plug 171 is constructed to have the proper number and configuration of conductors to mate with Self-Identifying Power Source 116 in well-known fashion. These conductors are connected to meter 570 which measures the energy consumption of the circuitry contained in Charging, Control, and Communicator module 410 . The principal load is converter module 550 which converts the electric voltage which appears on the conductors of plug 171 into current which is applied to battery assembly 420 thereby to charge battery assembly 420 in well-known fashion. The Processor 580 could call for a quick charge at a higher amperage, provided the Utility permits it; or the Processor 580 could call for a “trickle charge” over a number of hours. Processor 580 regulates the operation of charging module to controllably enable the charging of the battery assembly 420 (or such device that can store electrical energy) and to provide communications with the Utility Service Center 100 . In particular, the processor 580 receives the unique identification data from Self-Identifying Power Source 116 once the plug 171 is engaged in Self-Identifying Power Source 116 , or via wireless means such as using RFID without an actual physical connection as previously discussed, and then initiates a communication session with Utility Service Center 100 to execute the AAA process as described herein. The communications with the Utility Service Center 100 can be in the wireless mode via antenna 430 , or a wired connection 520 , or via the conductors of the plug 171 . An RFID reader 575 is provided to scan RFID devices associated with the outlet/electric meter/premises to which Vehicle 101 is sited to recharge battery assembly 420 as described herein. Finally, the ID communication can also be via PLC across the grid from the Utility wherein the Utility has, through its vast PLC network overlaid on its Electric Grid, created a unique ID for each Outlet, where a given ID is communicated from plug 171 to PLC Communication Module 560 . Given the grid is also a communication network with intelligence means any given outlet can have its ID dynamically modified per operational requirements of the Utility.
[0061] In addition, processor 580 is responsive to data transmitted from the Utility Service Center 100 to either activate or disable the converter module 550 as a function of the results of the AAA process. Once the charging process is completed, the processor 580 reads the data created by meter 570 and initiates a communication session via communications module 540 with the Utility Service Center 100 to report the identity of Vehicle 101 , the energy consumption in the present recharging session, and the associated unique identification of Self-Identifying Power Source 116 thereby to enable the utility company to credit the owner of Self-Identifying Power Source 116 and also bill the vehicle owner.
Load Management Process
[0062] The Utility can effect load management by permitting the current flowing through plug 171 as controlled by processor 580 which is in communication with Utility Service Center 100 to be at a specified level, or it can be terminated for given periods of time when peak load conditions are occurring on the grid, say due to a heat wave where air conditioners are all on maximum.
Energy Consumption Billing Process
[0063] FIG. 3 illustrates, in flow diagram form, the operation of the billing system for the E-Grid system; and FIG. 7 illustrates, in block diagram form, the communications interconnections in use in the E-Grid network. For example, Vehicle 101 at step 300 plugs into outlet 111 of Self-Identifying Power Source 116 and, at step 310 , receives the Self-Identifying Power Source 116 identification information as described above, such as via an RFID link. At step 320 , processor 580 accesses Communication Network 150 (or Power Line Carrier and Electric Grid 160 ) to communicate with Utility Service Center 100 and register on Grid Home Location Register 120 (or Grid Visitor Location Register 130 ). Vehicle 101 either is denied service at step 331 by Utility Service Center 100 due to a lack or credit, or lack of verification of identity, or gets authorization at step 330 from AAA System 110 to recharge the vehicle batteries 420 . As a part of the communication process, processor 580 communicates all of the “Utility Centric” data it derived when it plugged into the Self-Identifying Power Source 116 as described above (utility name, location of charging outlet, and so on). As one means for managing possible charging fraud, the location of the charging jack could be cross-correlated with a GPS location (where a GPS module could be inserted into CCC Module 410 (not shown for clarity).
[0064] An electrical power meter 570 inside Vehicle 101 measures the amount of energy being consumed at step 350 . When the plug 171 is pulled at step 360 , and charging is complete, the meter in Vehicle 101 initiates a communication session via communication module 540 with the Utility Service Center 100 to report the identity of Vehicle 101 , the energy consumption in the present recharging session, and the associated unique identification of Self-Identifying Power Source 116 thereby to enable the utility company to credit the owner of Self-Identifying Power Source 116 and also bill the vehicle owner. In addition, the vehicle owner can be charged for the energy consumption via their home account at step 370 , or via a roamer agreement at step 380 , or via a credit card at step 390 . At this point, if there were a property owner revenue share, this would also be recorded as a credit to that given property owner, and all billing is posted to the proper accounts at step 395 . In addition, at step 360 , the Utility Service Center 100 compiles the collected load data and transmits it to the local utility ( 155 on FIG. 1 and 233 , 234 on FIG. 2 ) to enable the local utility at step 340 to implement load control as described below.
A Simplified Communications Block Diagram—FIG. 7
[0065] In order to remove some of the architecture complexity, and to clearly describe the core invention in a slightly different manner, a minimalist figure ( FIG. 7 ) was created to show the key building blocks of the E-grid system communication architecture. There are two key architectural elements that enable the preferred embodiment described herein: (1) the placement of the meter measuring the power consumption during the charging sequence into the vehicle itself; and (2) the addition of the Utility Service Center 100 to manage Authentication, Authorization, and Accounting, where Utility Service Center 100 enables any electrical outlet to be available for charging and enables any utility to be a “member” of the “E-grid” system. As shown in FIG. 7 , a bidirectional communication network is created between the CCC (Charging, Control, and Communicator) Module 410 via Communications Network 150 and/or via Power Line Carrier via Electric Grid 160 to the Utility Service Center 100 . Within the CCC Module 410 is a meter 570 that measures the power consumed during a charging cycle, and it communicates the amount of energy consumed via CCC Module 410 to antenna 430 via Communications Network 150 or Plug 171 via Electric Grid 160 ultimately to Utility Service Center 100 . CCC Module 410 also receives the Self-Identifying Power Source 116 identification of the outlet 111 via RFID 613 and RFID Reader 575 . The pairing of the unique Outlet ID with the energy consumed and measured by the vehicle are transmitted to the Utility Service Center 100 and enable billing of the owner of the vehicle (or account holder for the vehicle), crediting of the owner of the physical plug (jack) where the power was taken from, and correct payment to the utility that supplied the energy.
Sub-Network Load Manager For Use In Recharging
[0066] FIG. 8 illustrates, in block diagram form, the architecture of a typical E-Grid application of the E-Grid Sub-Network Load Manager 803 , where an electric utility meter 801 and its associated main service disconnect 802 serve a plurality of circuit breakers 811 - 81 n , each of which serves a plurality of the Self-Identifying Power Sources (such as Self-Identifying Outlets 821 - 82 k ); and FIGS. 9A and 9B illustrate, in flow diagram form, the operation of the E-Grid Sub-Network Load Manager 803 .
[0067] As shown in FIG. 8 , a single electric utility meter 801 and its associated service disconnect 802 serve a plurality of circuit breakers 811 - 81 n , where each disconnect or circuit breaker (such as 811 ) serves a plurality of Outlets ( 821 - 82 k ). The E-Grid Sub-Network Load Manager 803 typically is associated with the electric utility meter 801 and its associated service disconnect 802 and serves to regulate the load presented by the vehicles connected to the plurality of Outlets served by the electric meter 801 and its associated service disconnect 802 .
[0068] As noted above, the Self-Identifying Outlet 821 at step 901 transmits its unique identification data to the vehicle 831 in order to enable the vehicle 831 to associate the power consumption as metered by the vehicle 831 with the Self-Identifying Outlet 821 , as described above. The E-Grid Sub-Network Load Manager 803 at step 902 in FIG. 9 is responsive to the connection of a vehicle 831 to outlet 821 of circuit breaker 811 to establish a communication session between vehicle 831 and E-Grid Sub-Network Load Manager 803 , typically via Power Line Communications. The communication session typically is brief and represents the exchange of basic information, such as transmitting the identification of the Self-Identifying Outlet 821 by the vehicle 831 to the E-Grid Sub-Network Load Manager 803 at step 903 , as well as the vehicle 831 transmitting its load characteristics at step 904 to the E-Grid Sub-Network Load Manager 803 . The load characteristics consist of the amount of energy required by the vehicle 831 to achieve a complete charge, as well as optionally the charging characteristics of vehicle 831 (current capacity, type of charger, etc.), the estimated time that the vehicle will be connected to the Self-Identifying Outlet 821 , the class of recharge service subscribed to by vehicle 831 , and the like.
[0069] At step 905 , the E-Grid Sub-Network Load Manager 803 computes the load presented by all of the Self-Identifying Outlets 821 - 82 k served by the circuit breaker 811 as well as the load presented by all of the circuit breakers 811 - 81 n to service disconnect 802 at step 906 . If the load is determined at step 907 to be within the service capacity of the circuit breaker 811 and service disconnect 802 , at step 908 the vehicle 831 is supplied with the power corresponding to the load presented by vehicle 831 . If the load presented by vehicle 831 , when combined with the loads presented by other vehicles served by service disconnect 802 , is determined at step 907 to exceed the current carrying capacity of circuit breaker 811 or the current carrying capacity of service disconnect 802 , the E-Grid Sub-Network Load Manager 803 reviews the accumulated data relating to the loads presented by the various vehicles served by service disconnect 802 .
[0070] This vehicle load data, as noted above, can be used at step 909 to identify criteria which can be used to modulate the load presented to the circuit breakers 811 - 81 n and service disconnect 802 . In particular, the load management algorithms used by E-Grid Sub-Network Load Manager 803 can be hierarchical in nature, such that a sequence of load management processes (stored in E-Grid Sub-Network Load Manager 803 ) can be successively activated to identify vehicles which can receive less than the full component of power to recharge their batteries, or an algorithm can be selected to cycle through the vehicles served by service disconnect 802 to maintain a power delivery level commensurate with the power handling capacity of the circuit breakers 811 - 81 n and service disconnect 802 .
[0071] For example, at step 910 , E-Grid Sub-Network Load Manager 803 , in response to the received load data, selects at least one algorithm to manage the load. The selection can be based upon historical data which indicates a typical or historical pattern of loads presented at this locale over time for this day of the week or day of the year. The present load can be compared to this typical or historical data to anticipate what loads can be expected in the immediate future, which comparison information can assist in the present decisions relating to load control. FIG. 9B illustrates a typical plurality of algorithms which can be used by E-Grid Sub-Network Load Manager 803 . At step 911 , a first E-Grid Sub-Network Load Manager 803 load management process queues the requests from the vehicles and serves each request in sequence until satisfaction. At step 912 , a second E-Grid Sub-Network Load Manager 803 load management process queues the requests and cycles through the requests, partially serving each request, then proceeding to the next until the cyclic partial charging service has satisfied all of the requests. At step 913 , a third E-Grid Sub-Network Load Manager 803 load management process orders the requests pursuant to a percentage of recharge required measurement, then proceeds to one of the above-noted service routines: serving each request in order to completion or cycling through the requests using a partial completion paradigm. At step 914 , a fourth E-Grid Sub-Network Load Manager 803 load management process orders the requests on an estimated connection time metric, then proceeds to one of the above-noted service routines: serving each request in order to completion or cycling through the requests using a partial completion paradigm. At step 915 , a fifth E-Grid Sub-Network Load Manager 803 load management process orders the requests on a predetermined level of service basis, then proceeds to one of the above-noted service routines: serving each request in order to completion or cycling through the requests using a partial completion paradigm. Finally, an intra-vehicle load management process (as described below) can be used to distribute power among a plurality of vehicles. Additional load management processes can be used, and these listed processes are simply presented for the purpose of illustration.
[0072] These load management processes can be implemented on a per circuit breaker, sub-network basis or can be implemented for the entirety of the Self-Identifying Outlets served by the service disconnect 802 . In addition, the E-Grid Sub-Network Load Manager 803 can select different processes for each circuit breaker sub-network and also can alter the load management process activated as new vehicles are either connected to Self-Identifying Outlets or depart from Self-Identifying Outlets or the various vehicles connected to Self-Identifying Outlets are recharged. Thus, the load management process implemented by the E-Grid Sub-Network Load Manager 803 is dynamic and varies in response to the load presented by the vehicles which are served.
[0073] The E-Grid Sub-Network Load Manager 803 typically implements control of the recharging of the vehicles by transmitting, at step 921 , control data to the vehicle 831 and/or other vehicles served by service disconnect 802 , which control data is used by processor 580 in vehicle 831 to either activate the vehicle's converter module 550 or disable the vehicle's converter module 550 . As the batteries in the vehicle 831 are recharged, the processor 580 dynamically determines the present state of recharge and can transmit data at step 922 to E-Grid Sub-Network Load Manager 803 to signal the completion of the recharge of the vehicle's batteries or provide a periodic recharge status report. At this juncture, E-Grid Sub-Network Load Manager 803 uses this data at the above-described step 905 to compute the action required to continue to manage the delivery of power to the plurality of vehicles served by service disconnect 802 . In particular, the E-Grid Sub-Network Load Manager 803 receives load update data from the vehicles as each vehicle is recharged and/or on a periodic update basis thereby to enable the E-Grid Sub-Network Load Manager 803 to manage the loads presented by the vehicles on a dynamic basis. The updated load data received from a vehicle optionally can be compared to the last load data from this vehicle used in computing load management. Thus, the original load data may be the baseline, or the last used updated load data may be the baseline. When the change in value between the baseline and the presently received updated load data exceeds a threshold, the updated load data then is used in the load management process described above. This optional threshold step can serve to reduce the load management computation iterations.
Intra-Vehicle Power Exchange Management
[0074] Another load management process is the intra-vehicle power exchange management process 916 , noted above, where power is drawn from the already charged (or partially charged) batteries of a vehicle and used to recharge the batteries of another vehicle served by service disconnect 802 . As an example, the load presented by all of the vehicles connected to the Self-Identifying Outlets served by service disconnect 802 or served by one or more circuit breakers (such as circuit breaker 811 ) can exceed the present capacity of the system to recharge these vehicles. If one or more of these vehicles are fully recharged or substantially recharged, power can flow from the batteries of these vehicles to the batteries of vehicles whose batteries have a remaining charge below some predetermined minimum threshold. This intra-vehicle power exchange process continues until the overall load on the E-Grid system drops to a level which enables the E-Grid system to serve the requests or when these vehicles are recharged to a predetermined level, where they can be queued up for regular service in due course. Thus, the intra-vehicle power exchange process can be an interim solution to ensure that all of the vehicles served by the service disconnect 802 are quickly recharged to some acceptable minimum level, then the standard recharging process is activated.
[0075] The intra-vehicle power exchange is illustrated, in flow diagram form, in FIG. 10 , where, at step 1001 , the E-Grid Sub-Network Load Manager 803 selects the load management process 916 for application to a plurality of the Self-Identifying Outlets 821 - 82 k , such as those served by circuit breaker 811 . At step 1002 , the E-Grid Sub-Network Load Manager 803 transmits control data to selected ones of the vehicles 831 , 832 to activate their processors 580 at step 1003 to switch the converter modules 550 from the battery charging mode to the DC-to-AC converter mode, where the power stored in the associated vehicle batteries is used to generate line voltage, which is applied by the converter modules 550 to the conductors which emanate from circuit breaker 811 to each Self-Identifying Outlet 821 - 82 k served by circuit breaker 811 . Alternatively, a DC delivery mode can be implemented at step 1004 where the Self-Identifying Outlets include DC conductors where the vehicle's converter module need not generate line voltage, but the DC voltage of the vehicle's batteries can be directly applied to the DC conductors of the associated Self-Identifying Outlet for use by the vehicle 83 k requiring an immediate recharge.
[0076] At step 1005 , the vehicle 83 k which requires the immediate recharge receives the line voltage generated by the other vehicles 831 , 832 and recharges its batteries via the operation of its converter module 550 . As this vehicle 83 k recharges its batteries and the other vehicles 831 , 832 have their batteries drained, data is transmitted from each vehicle at step 1006 to the E-Grid Sub-Network Load Manager 803 to enable the E-Grid Sub-Network Load Manager 803 to re-compute the need for the power exchange process at step 1007 to ensure that the vehicles 831 , 832 which are supplying the power do not drain their batteries below an acceptable level. As this process progresses, the E-Grid Sub-Network Load Manager 803 can at step 1008 transmit control data to a vehicle, such as vehicle 832 , to cause that vehicle to cease its participation of the power exchange process. Furthermore, at step 1009 , the E-Grid Sub-Network Load Manager 803 can terminate the power exchange process 916 and return vehicles 831 , 832 , 83 k to the routine recharge process as implemented by one or more of the load management processes 911 - 915 .
Centralized Load Management
[0077] The Utility Service Center 100 is the origination point for a Network-Wide Load Management situation, in which Vehicles 101 and 102 of FIG. 1 (or Vehicles 291 - 295 of FIG. 2 ) can be controlled to temporarily stop charging, where they are either not served by an E-Grid Sub-Network Load Manager 803 , or the Utility Service Center elects to override the operation of the E-Grid Sub-Network Load Manager 803 . There is a mapping algorithm that maps the geographic position of the charging device (via GPS) or via the Grid Identifier passed along by the Vehicle. The Utility knows that Vehicles 101 and 102 , for example, are in a region that is experiencing very heavy electrical demand. So, to help manage the demand, the Utility Company 155 , via Communication Network 150 (or via PLC across Electric Grid 160 to Utility Interface 114 ) sends a command to Vehicles 101 , 102 to temporarily stop charging (or until demand is lighter to re-initiate the charging sequence). In addition, the vehicles could be instructed to continue their charging sequence but charge at a lower level, or a given vehicle could ask for permission to charge at a very high rate to reduce the charge time.
Using The Stored Energy In The Vehicle Batteries As A Peaking Source Of Power For The Utility
[0078] As shown in FIG. 1 , Vehicles 101 , 102 are able to charge from the Electric Grid 160 via conductors 163 , and are also able to “push” energy back to the Electric Grid 160 via conductors 163 . Similarly, in FIG. 2 , Vehicles 291 - 295 are able to charge from the Electric Grids 240 , 250 via conductors 271 - 275 , and are able to “push” energy back to the Electric Grids 240 , 250 via conductors 271 - 275 . This “pushing” of energy from the vehicles' energy storage systems, whether they are batteries or some other form of energy storage device, permits the utilities to manage peak loads on the network by using the collective energy of all of the vehicles then connected to the E-Grid as “peakers”; and it would diminish the need for utilities to build “Peaking Power Plants”, which are very expensive to build and very expensive to operate, to handle the infrequent times when they need more energy to be supplied to the grid to prevent brownouts and blackouts.
SUMMARY
[0079] The present Self-Identifying Power Source For Use In Recharging Vehicles Equipped With Electrically Powered Propulsion Systems provides a unique identification of an outlet to a vehicle which is connected to the outlet to enable the vehicle to report the vehicle's power consumption to the utility company to enable the utility company to bill the vehicle owner and credit the outlet owner for the power consumed by the recharging of the vehicular battery banks. | The E-Grid Sub-Network Load Manager operates to regulate the demands presented by the vehicles to the associated Sub-Network thereby to spread the load presented to the service disconnect over time to enable the controllable charging of a large number of vehicles. The load management can be implemented by a number of methodologies, including: queuing requests and serving each request in sequence until satisfaction; queuing requests and cycling through the requests, partially serving each request, then proceeding to the next until the cyclic partial charging service has satisfied all requests; ordering requests pursuant to a percentage of recharge required measurement; ordering requests on an estimated connection time metric; ordering requests on a predetermined level of service basis; and the like. It is evident that a number of these methods can be concurrently employed thereby to serve all of the vehicles in the most efficient manner that can be determined. |
FIELD OF THE INVENTION
[0001] The present invention relates generally to machine elements and, more particularly, to pitmans and connecting rods.
BACKGROUND OF THE INVENTION
[0002] It is difficult to produce oil and gas in an economic manner from low permeability reservoir rocks. Production rates are often boosted by resorting to hydraulic fracturing, a technique that increases rock permeability by opening channels through which reservoir fluids can flow to recovery wells. During hydraulic fracturing, a fluid is pumped into the earth under high pressure where it enters a reservoir rock and fractures it. Proppants are carried in suspension by the fluid into the fractures. When the pressure is released, the fractures partially close on the proppants leaving channels for oil and gas to flow.
[0003] Specialized pumps are used to develop the pressures necessary to complete a hydraulic fracturing procedure or “frac job.” These pumps are usually provided with connecting rods that join a crosshead to a plunger that pressurizes a fluid. A conventional connecting rod is cast as a single unit and machined to desired tolerances. When portions of such a connecting rod wear out, the rod must be replaced in its entirety—a time-consuming, wasteful and costly undertaking. Multi-piece connecting rods have been developed as a substitute for one-piece rods with the purpose of permitting just the worn portions of a rod to be removed. Unfortunately, multi-piece rods have not gained widespread acceptance since wear has tended to occur not only in the usual locations, but, also, at the junctions between the joined pieces. Thus, the known multi-piece connecting rods, like the one-piece rods they were meant to supplant, often require a full replacement when partially worn.
SUMMARY OF THE INVENTION
[0004] In light of the problems associated with the known connecting rods, it is a principal object of the invention to provide a new connecting rod with two portions that can be easily disconnected from one another for replacement when worn. Once disconnected from one another, a worn portion can be removed and replaced while the other portion remains in place in a pump, thus saving time and money. Disconnection can be accomplished with ordinary tools and with minimal training.
[0005] It is another object of the present invention to provide a connecting rod of the type described that has a solid, self-aligning connection between its two principal portions. Such a connection impedes wear where the two portions contact one another and ensures that set-up will be proper prior to use.
[0006] It is another object of the invention to provide a connecting rod of the type described whose principal portions are integrally formed. Lacking welds and other mechanical connectors, each rod portion is designed for maximum strength.
[0007] It is an object of the invention to provide improved elements and arrangements thereof in a connecting rod for the purposes described which is lightweight in construction, inexpensive to manufacture, and dependable in use. Although the connecting rod is described as being of particular utility in oilfield pumps, it is anticipated that it will provide like benefits in other reciprocating engines and machines.
[0008] Briefly, the connecting rod in accordance with this invention achieves the intended objects by featuring a tubular shaft with a cylindrical section and a gusset section whose wall thickness varies with length. A major flange projects from the outer end of the gusset section whereas a minor flange projects from the outer end of the cylindrical section. The major and minor flanges have holes for the passage of threaded fasteners. A link has an alignment plug for insertion into a socket in the outer end of the cylindrical section of the shaft. A ring is secured to the alignment plug. A number of threaded fasteners releasably join the shaft and the link.
[0009] The foregoing and other objects, features and advantages of the present invention will become readily apparent upon further review of the following detailed description of the preferred embodiment as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention may be more readily described with reference to the accompanying drawings, in which:
[0011] [0011]FIG. 1 is a side elevational view of a connecting rod in accordance with the present invention with portions broken away to reveal details thereof.
[0012] [0012]FIG. 2 is a top view of the connecting rod of FIG. 1 with portions broken away.
[0013] [0013]FIG. 3 is a bottom view of the connecting rod.
[0014] Similar reference characters denote corresponding features consistently throughout the accompanying drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Referring now to the FIGS., a connecting rod in accordance with the present invention is shown at 10 . Connecting rod 10 includes a shaft 12 having major and minor flanges 14 and 16 at its opposed ends. Major flange 14 is configured for attachment to a bearing housing 18 and minor flange 20 is configured for attachment to a crosshead link 20 . Link 20 has an alignment plug 22 for insertion into a socket 24 in the center of minor flange 16 . A ring 26 is integrally formed with plug 22 and has a transverse aperture 28 for receiving a crosshead pin (not shown). A number of bolts 30 penetrating minor flange 16 and ring 26 releasably fasten shaft 12 and link 20 together.
[0016] Shaft 12 comprises an elongated, hollow tube whose outer and inner diameters vary along its length. As shown, shaft has a cylindrical section 32 with a constant outer diameter from which a gusset section 34 with a gradually increasing outer diameter extends to reinforce major flange 14 . A passageway 36 extends through shaft 12 and is enlarged in terms of diameter at both of its ends so as to form sockets 24 and 38 for receiving alignment plugs 22 and 40 of link 20 and bearing housing 18 . A peripheral wall 42 extends inwardly from cylindrical section 32 into passageway 36 and serves as an abutment for plug 22 and a reinforcement for shaft 12 adjacent flange 16 .
[0017] Major flange 14 is an outwardly projecting rim for strengthening the connection between shaft 12 and bearing housing 18 . For compactness, major flange 14 is provided with clipped, linear sides 44 that limit its outward projection from shaft 12 to front and back projections 46 and 48 . Projections 46 and 48 are each provided with a plurality of holes 50 arrayed around gusset section 34 . The centers of four holes 50 are arrayed to define a square. Through holes 50 , bolts 52 are extended for threaded attachment to bearing housing 18 .
[0018] Minor flange 16 is an outwardly projecting rim for strengthening the connection between shaft 12 and link 20 . Preferably, minor flange 16 is provided with an outline resembling a square whose sides 54 are parallel to sides 44 of major flange 14 . Each of the four corners of flange 16 is provided with a hole 56 through which a bolt 30 is extended for threaded attachment to link 20 . The centers of holes 56 define a square whose sides are parallel to that extending through the centers of four holes 50 .
[0019] Alignment plug 22 is a solid cylinder that fits snugly and fully into socket 24 so as to assure proper centering of link 20 on shaft 12 . Plug 22 projects from a flat surface 58 in the base of ring 26 . Preferably, four, threaded bores 60 penetrate surface 58 adjacent plug 22 and are positioned for alignment with holes 56 for the passage of bolts 30 . When bolts 30 are firmly tightened in bores 60 , the longitudinal axis of transverse aperture 28 is oriented at right angles to sides 44 and 54 of flanges 14 and 16 . To supply a flow of lubricant to aperture 28 and a crosshead pin within it, an opening 62 is provided in ring 26 opposite surface 58 .
[0020] From the foregoing, it will be appreciated that the use of connecting rod 10 is straightforward. Installation of connecting rod 10 in a pump is accomplished in a conventional a manner with shaft 12 and link 20 being joined by bolts 30 . After the pump has been run for substantial period, link 20 may show signs of wear about aperture 28 that serves as a bearing surface. (Shaft 12 is unlikely to show any wear since movement of bearing housing 18 and link 20 relative to flanges 14 and 16 during use is nil.) By untightening bolts 30 and manipulating the driving mechanism of the pump, a worn link 20 can be removed from shaft 12 and replaced by an unworn link 20 . Reinstalling bolts 30 in the new link 20 , permits the pump to be energized and operated. Since rod servicing does not require the removal of bearing housing 18 from the pump, it can be completed in substantially less time than is required with conventional connecting rods. Also, since only the worn link 20 is replaced, the waste of material that accompanies the removal of the shaft and bearing housing of a conventional connecting rod from a pump is eliminated.
[0021] While the invention has been described with a high degree of particularity, it will be appreciated by those skilled in the art that modifications may be made thereto. Therefore, it is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims. | A connecting rod including shaft with a major flange projecting outwardly from one of its ends and a minor flange projecting outwardly from the other of its ends. The major flange and the minor flange each have a number of holes for the passage of threaded fasteners. Abutting the minor flange is a ring with a transverse aperture. A number of threaded fasteners releasably join the shaft and the link together. |
TECHNICAL FIELD
The present invention relates to a fixing belt used for thermally fixing a toner image transferred onto a transfer-receiving body, such as recording paper, in an image forming apparatus, such as an electrophotographic copying machine, a facsimile machine, or a laser beam printer. More particularly, the invention relates to a fixing belt used for thermally fixing a toner image in an image forming apparatus using a plurality of kinds of color toners.
BACKGROUND ART
In image forming apparatuses, such as electrophotographic copying machines, facsimile machines, and laser beam printers, a thermal fixing method has been generally employed in which, in the final stage of printing/copying, a fixing belt (i.e., a fixing sleeve, fixing tube roller, or the like) provided with a heating source inside and a pressure roller are pressed into contact with each other, and a transfer-receiving body onto which a toner image has been transferred is passed therebetween, whereby unfixed toner is melted by heating.
As the fixing belt, there has been generally used a fixing belt having a structure in which a resin layer having excellent elasticity, releasability, wear resistance, and the like is disposed on a surface (surface to be in contact with a transfer-receiving body) of a tubular base member composed of a high-strength, heat-resistant resin, such as polyimide, or a fixing roller including a cylindrical base member composed of metal or polyimide and a resin layer having excellent elasticity, releasability, wear resistance, and the like disposed on the outer circumferential side of the base member. As the resin layer having excellent elasticity, releasability, wear resistance, and the like, a fluororesin coating layer has been widely used.
In order to obtain a good fixing property, it is necessary that a transfer-receiving body be sufficiently heated by a heating source provided inside a fixing belt. Consequently, the fixing belt is required to have excellent thermal conductivity.
Furthermore, in the fixing process of an image forming apparatus using a plurality of kinds of color toners, it is necessary to mix a plurality of kinds of color toners in a molten state when fixing is performed. Consequently, a fixing belt used for this purpose is required to have a proper degree of elasticity such that color toners are sufficiently enveloped so as to be melted and mixed.
As described above, since the fixing belt is required to have excellent thermal conductivity and a proper degree of elasticity, in order to satisfy these requirements, PTL 1 proposes a fixing belt including a heat-resistant elastomer layer (elastic layer) provided on the outer circumferential side of a tubular base member, and a fluororesin layer provided further thereon, in which the thickness of each of the tubular base member, the fluororesin layer, and the heat-resistant elastomer layer is specified, and the relationships between thickness, hardness, and thermal conductivity of the heat-resistant elastomer layer are defined so as to be within specific ranges (Claim 2 ). In order to satisfy these conditions, a technique is proposed in which an inorganic filler that improves thermal conductivity, such as silica, alumina, or boron nitride, is compounded into the heat-resistant elastomer (paragraph 0015).
Furthermore, PTL 2 discloses a fixing belt having a laminated structure in which a heat-resistant elastomer layer is disposed on the surface of a metal tube or heat-resistant plastic tube, and a silicone rubber or fluororesin layer is further disposed on the outer surface thereof, in which the deformation under load and the thickness of each of the layers are within predetermined ranges, and furthermore, the hardness and thermal conductivity of the heat-resistant elastomer layer are within predetermined ranges (Claim 1 ).
A method is also proposed in which, in order to set the thermal conductivity of the heat-resistant elastomer layer within the predetermined range, an inorganic filler that improves thermal conductivity, such as silica, alumina, or boron nitride, is compounded thereinto, and it is disclosed that by this method, heat from a heating source can be quickly supplied to the outer surface of the fixing belt (paragraph 0012).
CITATION LIST
Patent Literature
PTL 1: Japanese Patent No. 3735991
PTL 2: Japanese Patent No. 3712086
SUMMARY OF INVENTION
Technical Problem
However, in recent years, with the increase in printing speed, fixing belts have been required to have higher thermal conductivity. Accordingly, in order to achieve a fixing property that meets the user's strict requirements in recent years, an improvement in thermal conductivity has been desired because the thermal conductivity such as the one described in the cited art has been becoming insufficient.
In order to obtain higher thermal conductivity, a method is conceivable in which the amount of a filler (inorganic filler or the like) that improves thermal conductivity to be compounded is increased. However, in the fixing belt described in PTL 1 or 2, if the amount of the inorganic filler, such as silica, alumina, or boron nitride, is increased, elasticity of the fixing belt decreases, and it becomes difficult to obtain a proper degree of elasticity such that color toners are sufficiently enveloped so as to be melted and mixed.
It is an object of the present invention to provide a fixing belt which has high thermal conductivity capable of responding to the recent increase in printing speed, which has a proper degree of elasticity such that color toners are sufficiently enveloped so as to be melted and mixed, and which has excellent mechanical strength and durability.
Solution to Problem
As a result of diligent research, the present inventors have found that in a fixing belt including a tubular base member, a surface layer, and an elastic layer disposed between the base member and the surface layer, by using as a material for the elastic layer rubber into which a filler primarily composed of silicon carbide powder and a carbon nanotube are compounded, and by setting the compounding ratio between the filler and the carbon nanotube in the range expressed by predetermined formulae, both high thermal conductivity and a proper degree of elasticity can be achieved, and mechanical strength is not decreased, and thus the present invention has been completed. That is, the problems described above are solved by the invention having the constitution described below.
The invention according to Claim 1 relates to a fixing belt including a tubular base member, an elastic layer disposed on the outer circumferential side of the base member, and a surface layer disposed on a surface on the outer circumferential side of the elastic layer, the fixing belt being characterized in that the elastic layer is composed of rubber into which a filler primarily composed of silicon carbide powder (hereinafter, may be abbreviated as “SiC”) and a carbon nanotube (hereinafter, may be abbreviated as “CNT”) are compounded, and the formulae 10X+3Y<750, 3X+30Y>170, X>10, and Y>0.1 are satisfied, where X is the percent by volume of the filler and Y is the percent by volume of the CNT in the elastic layer.
As described above, in the fixing belt, in order to achieve excellent thermal conductivity that satisfies the recent requirements, it is necessary to increase the compounding ratio of a filler, such as silica, alumina, or boron nitride, to the elastic layer. In such a case, the elastic layer hardens, and it is not possible to obtain a proper degree of elasticity such that color toners are sufficiently enveloped so as to be melted and mixed. However, when a filler primarily composed of SiC is used together with a CNT and the compounding amounts of these are set within the range expressed by the formulae described above, it is possible to achieve both excellent thermal conductivity that sufficiently satisfies the recent requirements and a proper degree of elasticity, and also higher durability can be obtained.
A CNT is composed of carbon crystals (graphite or the like) and has a short axis diameter (fiber diameter) of submicron size or less. For example, a CNT has a configuration in which a layer of graphite is rolled into a tube. It is known that CNTs are compounded into a resin or the like to improve thermal conductivity. CNTs have a true specific gravity of 2.0 g/cm 3 and usually have an aspect ratio of 50 to 1,000. A graphite structure-type CNT having such a high aspect ratio is desirably used.
Typical examples of CNTs include single-wall CNTs and multi-wall CNTs having a concentric internal structure. Examples of CNTs also include carbon nanofibers (CFs) having a fiber diameter of 1 μm or less (submicron size or less) and CNTs in which several bottomless cup-shaped carbon material layers are stacked. In addition, Japanese Unexamined Patent Application Publication No. 2004-123867 discloses a polyimide tube into which a CNT is compounded. However, since the CNT is compounded into a polyimide resin, mechanical strength markedly decreases when the compounding ratio is increased.
The filler used in the present invention is characterized by being primarily composed of SiC. The term “primarily composed of” means both a case where the filler is composed of SiC only and a case where the filler is mostly composed of SiC (preferably in an amount of 80% by volume or more), and another filler is included within a range that does not impair the gist of the present invention. The present inventors have found that when a filler primarily composed of SiC is used, excellent adhesion between the elastic layer and the other layer can be obtained, thus preventing the occurrence of peeling during use of a printer (copying machine), and thermal conductivity is further improved.
SiC is powder of silicon carbide. The mean particle diameter of SiC is preferably 10 μm or less. When the mean particle diameter exceeds 10 μm, there is a possibility that hardness of the elastic layer may become too high or durability may be degraded. Furthermore, as the other filler that can be included within a range that does not impair the gist of the present invention, a substance which is compounded as a filler that improves thermal conductivity in conventional fixing belts can be used. Examples thereof include alumina, silica, boron nitride, graphite, metal silicon, and the like.
The present invention is characterized in that the formula 10X+3Y<750 is satisfied, where X is the percent by volume of the filler (primarily composed of SiC) and Y is the percent by volume of the CNT in the elastic layer. When 10X+3Y is greater than or equal to 750, the elastic layer hardens and it becomes difficult to obtain a proper degree of elasticity such that color toners are sufficiently enveloped so as to be melted and mixed. (The 10X+3Y value is highly correlated with hardness of the elastic layer. Therefore, hereinafter, the 10X+3Y value may be referred to as a “hardness index”). 10X+3Y is preferably less than 650, and more preferably less than 600, which results in a better fixing property.
Note that X and Y mean percentages (%) of absolute volumes of the filler and the CNT, respectively, when the entire volume of the elastic layer is set to be 100%. The absolute volume can be easily calculated from the weight and specific gravity of each of them.
The present invention is also characterized in that 3X+30Y>170. When 3X+30Y is less than or equal to 170, it is not possible to obtain an excellent fixing property. (The 3X+30Y value is highly correlated with thermal conductivity of the elastic layer. Therefore, hereinafter, the 3X+30Y value may be referred to as a “thermal conduction index”). 3X+30Y is preferably greater than or equal to 180, and more preferably greater than or equal to 200, which results in a better fixing property.
The present invention is characterized in that the CNT is contained in the elastic layer so as to satisfy the formula Y>0.1. In the case where the CNT is not contained, i.e., in the case where Y=0, it is necessary to increase the compounding ratio of the filler, and as a result, a proper degree of elasticity cannot be obtained. By setting the CNT content within a range satisfying the formula Y>0.1, the compounding ratio of the filler can be decreased, and as a result, a more proper degree of elasticity can be achieved.
On the other hand, the upper limit of Y is preferably less than or equal to 40, and more preferably less than or equal to 5. When the amount of CNT is too large, the viscosity of an application liquid used for forming the elastic layer becomes too high, which may cause a problem in terms of application properties.
In order to achieve excellent adhesion and thermal conductivity of the elastic layer, it is necessary to set X to be greater than 10.
As a material (matrix) constituting the elastic layer, a heat-resistant elastomer that is used for an intermediate layer for imparting elasticity in conventional fixing belts can be used. The matrix is not necessarily limited to vulcanized rubber, and a material which is not easily degraded by heating when the fixing belt is produced and used and which has elasticity can be used. As the heat-resistant elastomer, silicone rubber or fluororubber is preferably used because of its excellent heat resistance (Claim 2 ).
As the material for the surface layer, a fluororesin which has excellent toner releasability, durability, and color toner fixing property is preferably used (Claim 3 ).
Examples of the tubular (tube-shaped) base member include a tubular base member composed of a flexible material and a cylindrical base member. Consequently, examples of the fixing belt (fixing sleeve) of the present invention include a fixing belt having a structure including a tubular base member composed of a flexible material, an elastic layer disposed on the outer circumferential side thereof, and a surface layer disposed on the outer circumferential side of the elastic layer, and a fixing roller having a structure including a cylindrical base member, an elastic layer disposed on the outer circumferential side thereof, and a surface layer disposed on the outer circumferential side of the elastic layer.
As the material for the tubular base member, specifically, a metal tube or heat-resistant plastic tube can be used (Claim 4 ). As the tubular base member composed of a flexible material, a tube-shaped film (tube) composed of polyimide or polyamide-imide is preferably used because of its excellent heat resistance and mechanical strength (Claim 5 ). In order to improve the thermal conductivity of the base member, an inorganic filler or the like may be added as long as mechanical strength can be kept. As the cylindrical base member, a metal tube or the like can also be used.
In a fixing belt (fixing sleeve), when adhesion among the individual layers is insufficient, interlayer peeling may occur during use of a printer (copying machine). In the fixing belt (fixing sleeve) of the present invention, by using SiC as a filler contained in the elastic layer, excellent adhesion between the elastic layer and the other layer is exhibited. In order to further improve adhesion among the individual layers, usually, a lower primer layer (i.e., a primer layer provided between the base member and the elastic layer) is provided between the base member and the elastic layer, and an upper primer layer (i.e., a primer layer provided between the elastic layer and the surface layer) is provided between the elastic layer and the surface layer.
Furthermore, in order to improve adhesion among the base member/lower primer layer/elastic layer, the methods 1 and 2 described below may be employed.
Method 1
In this method, silicone rubber is selected as the rubber constituting the elastic layer, and an appropriate amount of an adhesive component is added into silicone rubber. As a result of research, the present inventors have found that by adding a specific adhesive component, silane coupling agent, or rubber-based resin for primer use to the elastic layer in an appropriate amount, i.e., in the range described below, adhesion is improved and durability during paper passing is increased without impairing high thermal conductivity and adequate rubber elasticity.
Claims 6 and 7 each relate to a fixing belt obtained by this method. Claim 6 relates to the fixing belt according to any one of Claims 1 to 5 , characterized in that the base member and the elastic layer are bonded to each other with a lower primer layer, the rubber constituting the elastic layer is silicone rubber, and in the elastic layer, a silane coupling agent is compounded in an amount of 0.5% to 5% by weight relative to the silicone rubber. Claim 7 relates to the fixing belt according to any one of Claims 1 to 5 , characterized in that the base member and the elastic layer are bonded to each other with a lower primer layer, the rubber constituting the elastic layer is silicone rubber, and in the elastic layer, a rubber-based resin for primer use is compounded in an amount of 0.1% to 3% by weight relative to the silicone rubber.
Here, as the silane coupling agent, an organosilicon compound having in its molecule a reactive group (methoxy group, ethoxy group, silanol group, or the like) that chemically binds to an inorganic substance and a reactive group (vinyl group, epoxy group, methacryl group, amino group, mercapto group, or the like) that chemically binds to an organic material may be used, and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane. Above all, organosilicon compounds having a methoxy group and an epoxy group are preferable, and commercially available such compounds under the trade name KBE-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be used.
As the rubber-based resin for primer use, commercially available products can be used. Preferably, the type thereof is selected depending on the base member. For example, in the case where the base member is a metal, preferred examples of the rubber-based resin for primer use include X-33-173 (manufactured by Shin-Etsu Chemical Co., Ltd). In the case where the base member is a resin, such as polyimide, preferred examples of the rubber-based resin for primer use include X-33-174 and X-33-176-1 (manufactured by Shin-Etsu Chemical Co., Ltd).
Method 2
In this method, silicone rubber is selected as the rubber constituting the elastic layer, and silicone rubber is added to the primer layer. Claim 8 relates to a fixing belt obtained by this method and relates to the fixing belt according to any one of Claims 1 to 5 , characterized in that the base member and the elastic layer are bonded to each other with a lower primer layer, the rubber constituting the elastic layer is silicone rubber, and the lower primer layer contains silicone rubber.
Although the type of silicone rubber is not particularly limited, rubber having a low content of filler and high adhesion is preferable. The amount of silicone rubber to be added is preferably about 0.1% to 30% by weight relative to the lower primer layer.
The method of producing the fixing belt of the present invention is not particularly limited. For example, a fixing belt can be produced by applying, with a dispenser, a heat-resistant elastomer, such as silicone rubber or fluororubber, onto the outer circumferential side of a tubular base member or cylindrical base member serving as an innermost layer, followed by curing to form an elastic layer, then applying a dispersion liquid of a fluororesin thereonto, and sintering the fluororesin by heat treatment to form a surface layer. Preferably, in order to improve adhesion among the individual layers, a lower primer layer is formed on the outer circumferential surface of the base member before applying the heat-resistant elastomer, and an upper primer layer is formed on the outer circumferential surface of the elastic layer before applying the dispersion liquid of the fluororesin.
Alternatively, an elastic layer may be formed by producing a heat-shrinkable tube composed of a heat-resistant elastomer into which a vulcanizing agent is compounded, and putting the tube on the circumferential side of the base member, followed by heat shrinking.
The fixing belt of the present invention is used in a fixing section of various types of image forming apparatuses. In the fixing section, a heating source is provided inside the fixing belt, the fixing belt is opposed to and pressed into contact with a pressure roller composed of a rubber roller or the like, and a transfer-receiving body onto which a toner image has been transferred is passed therebetween, whereby unfixed toner is melted by heating to be fixed.
Advantageous Effects of Invention
A fixing belt of the present invention has high thermal conductivity capable of achieving an excellent fixing property that can respond to the recent increase in printing speed, and has a proper degree of elasticity such that color toners are sufficiently enveloped so as to be melted and mixed. Furthermore, in the fixing belt, mechanical strength is not degraded, and excellent adhesion between the elastic layer and the other layer is exhibited.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a cross-sectional view orthogonal to the axis of rotation of an example of a fixing belt according to the present invention.
DESCRIPTION OF EMBODIMENTS
Embodiments of the present invention will be described below. However, it is to be understood that the present invention is not limited to the embodiments, and the present invention can be modified within a range not deviating from the gist of the present invention.
FIG. 1 is a view schematically showing an example of a fixing belt (roller) of the present invention, and is a cross-sectional view orthogonal to the axis of rotation of the fixing belt. In FIG. 1 , reference sign 1 denotes a base member, reference sign 3 denotes an elastic layer, and reference sign 5 denotes a surface layer. Furthermore, a primer layer 2 (lower primer layer) and a primer layer 4 (upper primer layer) for improving adhesion are provided between the base member 1 and the elastic layer 3 and between the elastic layer 3 and the surface layer 5 , respectively.
In the example of FIG. 1 , the base member 1 is an endless belt composed of a polyimide resin. As the base member 1 , in addition to this, a cylinder composed of resin or metal, or a columnar solid body (roller) can also be used. Furthermore, as the resin material for the endless belt, a polyamide-imide resin can be used instead of the polyimide resin. However, in terms of heat resistance, modulus of elasticity, strength, and the like, a polyimide resin is preferable.
The base member 1 is produced by applying an organic solvent solution of a polyimide precursor (polyamic acid), (i.e., polyimide varnish), into which an appropriate amount of a filler for improving thermal conductivity is compounded, onto the outer circumferential surface of a cylindrical core composed of metal by a dispenser method, followed by heating to about 350° C. to 450° C. to convert the precursor into a polyimide by dehydration and ring-closing. Examples of the polyimide varnish include U Varnish S of Ube Industries, Ltd., and examples of the organic solvent include N-methyl-2-pyrrolidone and dimethylacetamide, although not limited thereto.
The thickness of such an endless belt composed of the polyimide resin is preferably about 30 to 80 μm in view of durability and elasticity.
As the material for the elastic layer 3 , as described above, silicone rubber or fluororubber having excellent heat resistance is preferable. In particular, an elastic layer having a two-layer structure in which a silicone rubber layer is arranged on the base member 1 side, and a fluororubber layer with a thickness of 20 to 100 μm is disposed thereon on the surface layer side is preferable in view of heat resistance and adhesion to the surface layer. That is, since the fluororubber layer is present on the surface layer 5 side, excellent adhesion to the surface layer 5 having a matrix made of fluororesin is exhibited. Furthermore, since fluororubber has good heat resistance, the silicone rubber layer is prevented from being damaged by heat during the formation of the surface layer. Furthermore, since the silicone rubber layer is present on the base member 1 side, the two-layer structure is also preferable in view of elasticity.
In order to improve the fixing property, the elastic layer 3 is required to excel in elasticity in the thickness direction. Accordingly, the hardness (JIS-A hardness) measured by the spring type hardness test, type A, according to JIS K6301 of the elastic layer 3 is preferably 10 to 60, and particularly preferably 10 to 40. Furthermore, the thickness of the elastic layer 3 is preferably 0.1 to 0.5 mm, and more preferably 0.2 mm or more.
In the conventional technique, it has been difficult to satisfy both a proper degree of elasticity and high thermal conductivity. The method of the present invention can satisfy both of them, and as a result, it is possible to obtain a fixing property capable of sufficiently responding to higher speed color printing.
The CNT used in the present invention can be produced by an arc discharge method, a laser ablation method, a plasma synthesis method, an electrolytic method, an electron beam irradiation method, a vapor deposition method, or the like. In particular, CNTs produced by the arc discharge method, the laser ablation method, and the vapor deposition method make it easy to control the configuration, such as diameter and length, and therefore, these methods are preferable as the method of producing CNTs used in the present invention. Above all, the vapor deposition method is particularly preferable because the control is particularly easy.
Examples of CNTs produced by the vapor deposition method include CNTs manufactured by Hyperion Catalysis International, Inc., Showa Denko K. K., Nikkiso Co., Ltd., Carbon Nanotech Institute, GSI Creos Corporation, and the like. Examples of the specific commercial product include VGCF-H manufactured by Showa Denko K. K.
The short axis diameter of the CNT is, although not particularly limited, preferably 0.5 μm or less, more preferably 0.3 μm or less, and particularly preferably 0.2 μm or less. As the short axis diameter decreases, the number of fibers increases for the same weight added, and an excellent effect of improving thermal conduction is exhibited, thus being preferable. Furthermore, there are a wide variety of types of CNTs including single-wall to multi-wall (double-wall) CNTs. The long axis diameter of the CNT is, although not particularly limited, preferably 50 μm or less, more preferably 40 μm or less, and particularly preferably 30 μm or less. When the short axis diameter and the long axis diameter are out of the ranges described above, it tends to become difficult to balance between thermal conductivity and mechanical strength.
Examples of the fluororesin used as the material for the surface layer 5 disposed on the outer circumferential side of the elastic layer 3 include a polytetrafluoroethylene resin (PTFE), a tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), a tetrafluoroethylene-hexafluoropropylene copolymer, and the like. In particular, in view of heat resistance, PTFE or PFA is preferably used.
The thickness of the surface layer 5 composed of a fluororesin is preferably 10 to 50 μm, more preferably 10 to 35 μm, and still more preferably 10 to 25 μm. When the thickness of the fluororesin layer is too small, durability is poor, and there is a possibility that the layer will be worn away early as the number of copies increases, resulting in degradation in releasability. When the thickness of the fluororesin layer is too large, the surface of the fixing belt hardens and the color toner fixing property is degraded.
The material for the primer layers 2 and 4 is not particularly limited. In view of adhesion, a rubber-based primer is preferable for the primer layer 2 , and a fluoro-primer is preferable for the primer layer 4 .
EXAMPLES
Examples 1 to 8, Reference Examples 1 to 3, and Comparative Examples 1 to 5
A fixing belt (i.e., a fixing sleeve including a base member 1 , a primer layer 2 , an elastic layer 3 , a primer layer 4 , and a surface layer 5 ) shown in FIG. 1 was produced using the procedure described below.
[Production of Base Member 1 ]
An organic solvent solution of a polyimide precursor (polyimide varnish, manufactured by Ube Industries, Ltd., trade name: U Varnish S) into which an appropriate amount of a filler for improving thermal conductivity was compounded was applied onto the outer circumferential surface of a cylindrical core composed of metal by a dispenser method. Heating was performed to about 350° C. to 450° C. to convert the precursor into a polyimide by dehydration and ring-closing. Then, the resulting product was detached from the cylindrical core to obtain a tubular base member 1 . In addition, the base member 1 had a size of 50 μm in thickness, 26 mm in inside diameter, and 24 cm in length.
[Primer Layer 2 ]
X-33-174A/B (rubber-based primer) manufactured by Shin-Etsu Chemical Co., Ltd. was applied onto the base member 1 to form a primer layer 2 . The thickness of the primer layer 2 after drying was about 10 μm.
[Production of Elastic Layer 3 ]
The filler and CNT shown in any of Tables I to IV in the amounts shown in any of Tables I to IV were mixed into known silicone rubber having a methyl side chain using a triple roll mill for each example. The resulting mixture was applied onto the outer circumferential surface of the primer layer 2 using a dispenser, and then shaping was performed by heat curing. Thereby, an elastic layer 3 with a thickness of 275 μm was obtained. Furthermore, the fillers and CNT used for the production of the elastic layer 3 are shown below.
(Filler)
1. SiC: SiC with a mean particle diameter of 1 μm was used. In the tables below, shown as “SiC”.
2. Metal silicon: M-Si #600 (trade name) manufactured by Kinsei Matec Co., Ltd.; crushed form; mean particle diameter: about 6.0 μm. In the tables below, shown as “metal Si”.
3. Alumina: Alumina CB-A10 (trade name) manufactured by Showa Denko K. K.; spherical shape; mean particle diameter: 10 mm. In the tables below, shown as “alumina”.
4. Silica: FB-8S (trade name) manufactured by Denki Kagaku Kogyo K. K.; spherical shape; mean particle diameter: about 6.5 μm. In the tables below, shown as “silica”.
(CNT)
Carbon nanotube VGCF-H (trade name) manufactured by Showa Denko K. K. was used. The CNT has a configuration in which the short axis diameter is 150 nm, and the long axis diameter is 6 μm.
The percent by volume X of the filler and the percent by volume Y of the CNT are calculated on the basis of the weight of each of silicone rubber, the filler, and the CNT used and the specific gravity of each of them. When two or more types of filler are used, the total percent by volume thereof is set to be X.
[Primer Layer 4 ]
Using 855N-703 (fluoro-primer) manufactured by DuPont, a primer layer 4 was formed on the elastic layer 3 .
[Production of Surface Layer 5 ]
A fluororesin coating (PFA: 855N-713 manufactured by DuPont) was applied onto the primer layer 4 , followed by treatment at about 340° C. to form a surface layer 5 (fluororesin layer). Thereby, a fixing belt shown in FIG. 1 was obtained. The thickness of the fluororesin layer was 15 μm.
Regarding the fixing belts produced as described above, the fixing property, hardness, thermal conductivity, and adhesion among the base member 1 /primer layer 2 /elastic layer 3 were measured by the methods described below, and a durability test was carried out. The results thereof are shown in Tables I to IV.
[Evaluation of Fixing Property]
Using the fixing belts produced, a color image was actually printed and evaluated. The surface temperature was set to 150° C. and the pressing force was set to 6 kg during printing. Furthermore, paper passing conditions during printing were such that 10 sheets of A4 size printing paper were continuously printed at 25 sheets/min, and the presence or absence of color unevenness and the presence or absence of roughness were determined visually. The results thereof are shown in Tables I to IV on the basis of the following criteria:
⊙: Neither color unevenness nor roughness was observed.
◯: Color unevenness was not observed, but roughness was observed.
×: Color unevenness and roughness were both observed.
[Evaluation of Hardness and Thermal Conductivity]
Hardness was measured with a JIS-A hardness tester according to JIS K 6253. Thermal conductivity is the value obtained by multiplying the thermal diffusivity obtained by measurement with a periodic heating method measuring instrument FTC-1 manufactured by ULVAC-RIKO, Inc. by the specific heat measured according to JIS K 7123 and the density measured according to the method of JIS K 7112A.
[Evaluation of adhesion]
Evaluation was performed by measuring 180° peeling strength. Specifically, base rubber (silicone rubber) was formed at a predetermined thickness on a polyimide base member. A sample in which the base rubber was bonded to the polyimide base member by an adhesive was cut to a width of 1 cm, and the polyimide base member side was pulled by a tensile tester to measure the 180° peeling strength at the interface between the polyimide base member and the base rubber.
[Durability Test]
Using the fixing belts produced, a color image was actually printed. The surface temperature was set to 150° C. and the pressing force was set to 6 kg during printing. Furthermore, paper passing conditions during printing were such that sheets of A4 size printing paper were continuously printed at 25 sheets/min for 70 hours. The presence or absence of peeling among the base member 1 /primer layer 2 /elastic layer 3 of the fixing belt was visually observed, and evaluation was performed on the basis of the evaluation criteria described below.
[Evaluation Criteria]
⊙: No peeling occurs.
◯: Peeling hardly occurs.
Δ: Peeling occurs in some cases, but at a practically allowable level.
×: Peeling occurs in large numbers and not at a practical level.
TABLE I
Reference
Example 1
Example 2
Example 1
Type of rubber of elastic layer
Silicone
Silicone
Silicone
Filler
Type
SiC
SiC
Metal Si
Vol. % X
42
42
42
CNT Vol. % Y
1.5
2
2
Hardness index: 10X + 3Y
425
426
426
Thermal conduction index:
171
186
186
3X + 30Y
Fixing property
◯
⊚
⊚
Hardness (degree)
19
20
20
Thermal conductivity
1.8
2.0
1.8
(W/m · K)
Additive to elastic layer
None
None
None
Adhesion (g/cm)
180
180
170
Durability test
◯
◯
◯
TABLE II
Refer-
Refer-
ence
ence
Exam-
Exam-
Exam-
Exam-
Exam-
ple 3
ple 4
ple 5
ple 2
ple 3
Type of rubber of
Sili-
Sili-
Sili-
Sili-
Sili-
elastic layer
cone
cone
cone
cone
cone
Filler
Type
SiC
SiC
SiC
Alu-
Metal
mina
Si
Vol. % X
50
50
50
50
50
CNT Vol. % Y
1
1.5
2
2
2
Hardness index:
503
505
506
506
506
10X + 3Y
Thermal conduction
180
195
210
210
210
index: 3X + 30Y
Fixing property
⊚
◯
⊚
⊚
⊚
Hardness (degree)
22
23
24
20
24
Thermal conductivity
2.0
2.0
2.1
2.0
2.0
(W/m · K)
Additive to
None
None
None
None
None
elastic layer
Adhesion(g/cm)
170
160
160
100
150
Durability test
◯
◯
◯
Δ
◯
TABLE III
Example 6
Example 7
Example 8
Type of rubber of elastic layer
Silicone
Silicone
Silicone
Filler
Type
SiC
SiC
SiC
Vol. % X
60
60
60
CNT Vol. % Y
1
1.5
2
Hardness index: 10X + 3Y
603
605
606
Thermal conduction index:
210
225
240
3X + 30Y
Fixing property
◯
◯
◯
Hardness (degree)
27
28
29
Thermal conductivity
2.2
2.3
2.5
Additive to elastic layer
None
None
None
Adhesion (g/cm)
150
140
130
Durability test
◯
◯
◯
TABLE IV
Comparative
Comparative
Comparative
Comparative
Comparative
Example 1
Example 2
Example 3
Example 4
Example 5
Type of rubber of
Silicone
Silicone
Silicone
Silicone
Silicone
elastic layer
Filler
Type
Silica
Alumina
Alumina
Alumina
Alumina
Vol. % X
30
50
80
40
75
CNT Vol. % Y
0
0
0
1
10
Hardness index:
300
500
800
403
780
10X + 3Y
Thermal conduction
90
150
240
150
525
index: 3X + 30Y
Fixing property
X
X
X
X
X
Hardness (degree)
12
15
40
16
42
Thermal conductivity
0.5
1.1
2.0
1.2
7.0
(W/m · K)
Adhesion(g/cm)
250
120
50
120
30
Durability test
Δ
Δ
X
Δ
X
Tables I to IV show the evaluation results of the fixing property and the like together with the hardness index and the thermal conduction index calculated from the percentages by volume of the filler and CNT. As is evident from the results of Tables I to IV, in Comparative Example 1 into which the filler and CNT are not compounded and in Comparative Examples 2 and 4 in which the thermal conduction index is less than or equal to 170, an excellent fixing property is not obtained. The reason for this is believed to be that the thermal conductivity is too low. Furthermore, in Comparative Examples 3 and 5 in which the hardness index is greater than or equal to 750, an excellent property is also not obtained. The reason for this is believed to be that the elastic layer is too hard and melting and mixing of color toners are insufficient.
In contrast, in Examples 1 to 8 into which the CNT is compounded and in which the hardness index and the thermal conduction index are within the ranges of the present invention, an excellent fixing property is obtained, and adhesion and the result of the durability test are excellent.
Furthermore, in Reference Example 2 in which alumina is used as the filler, an excellent fixing property is obtained. However, as is obvious from comparison between Example 5 and Reference Example 2 (the same conditions except for the type of filler), in the example of the present invention (Example 5) in which SiC is used as the filler, better thermal conductivity is exhibited, and in particular, adhesion and the result of the durability test are much better, indicating that by compounding SiC as the filler, adhesion among the base member 1 /primer layer 2 /elastic layer 3 is improved, and a fixing belt having excellent durability can be obtained.
In Reference Examples 1 and 3 in which metal silicon is used as the filler, an excellent fixing property is obtained, and adhesion and the results of the durability test are better than those of the case where alumina is used as the filler (Reference Example 2). However, as is obvious from comparison between Example 2 and Reference Example 1 (the same conditions except for the type of filler) and between Example 5 and Reference Example 3 (the same conditions except for the type of filler), the examples of the present invention (Examples 2 and 5) in which SiC is used as the filler excel in thermal conductivity and adhesion compared with the case where metal silicon is used. Examples 9 to 11 and Reference Examples 4 and 5
A fixing belt shown in FIG. 1 was produced as in Example 5 except that, in the production of the elastic layer 3 , KBE-403 (3-glycidoxypropyltrimethoxysilane, silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd.) in the amount shown in Table V was added to silicone rubber. Regarding the fixing belt, the physical properties described above were measured. The results thereof are shown in Table V. Note that, in the table, the amount of KBE-403 added is indicated in terms of parts by weight relative to 100 parts by weight of silicone rubber.
TABLE V
Refer-
Refer-
ence
ence
Exam-
Exam-
Exam-
Exam-
Exam-
ple 9
ple 10
ple 11
ple 4
ple 5
Type of rubber of
Sili-
Sili-
Sili-
Sili-
Sili-
elastic layer
cone
cone
cone
cone
cone
Filler
Type
SiC
SiC
SiC
Alu-
Metal
mina
Si
Vol. % X
50
50
50
50
50
CNT Vol. % Y
2
2
2
2
2
Hardness index:
506
506
506
506
506
10X + 3Y
Thermal conduction
210
210
210
210
210
index: 3X + 30Y
Fixing property
⊚
⊚
⊚
⊚
⊚
Hardness (degree)
24
24
24
20
24
Thermal conductivity
2.1
2.1
2.1
2.0
2.0
(W/m · K)
Additive
Type
KBE-
KBE-
KBE-
KBE-
KBE-
to elastic
403
403
403
403
403
layer
Amount of
1
3
5
3
3
addition
Adhesion
180
180
170
120
180
Durability test
⊚
⊚
⊚
◯
⊚
In Examples 9 to 11, the elastic layer 3 is formed using silicone rubber, and a silane coupling agent is further added thereto (corresponding to Claim 6 ). As is obvious from the results of Table V, in the examples of the present invention, an excellent fixing property is obtained and adhesion among the base member 1 /primer layer 2 /elastic layer 3 and the result of the durability test are excellent. Moreover, adhesion and the result of the durability test are better than those of Example 5 in which the same conditions are used except that the silane coupling agent is not added. Consequently, the results of Table V show that by forming the elastic layer 3 using silicone rubber and by further adding a silane coupling agent thereto, adhesion among the base member 1 /primer layer 2 /elastic layer 3 is improved.
Furthermore, in Reference Example 4, in which alumina is used as the filler and the other conditions are the same as those of Example 10, an excellent fixing property is obtained. However, as is obvious form comparison between Example 10 and Reference Example 4, in the example of the present invention (Example 10) in which SiC is used as the filler, thermal conductivity is better, and adhesion and the durability test are largely improved, indicating that by compounding SiC as the filler, adhesion among the base member 1 /primer layer 2 /elastic layer 3 is improved, and a fixing belt having excellent durability can be obtained.
In Reference Example 5 in which metal silicon is used as the filler and the other conditions are the same as those of Example 10, the fixing property, adhesion, and the result of the durability test are similarly excellent. However, as is obvious from comparison between Example 10 and Reference Example 5, in the example of the present invention (Example 10) in which SiC is used as the filler, thermal conductivity excels compared with the case where metal silicon is used.
Examples 12 to 14
A fixing belt shown in FIG. 1 was produced as in Example 5 except that, in the production of the elastic layer 3 , X-33-174A/B (rubber-based primer; hereinafter, may be abbreviated as X-33-174) manufactured by Shin-Etsu Chemical Co., Ltd. in the amount shown in Table VI was added to silicone rubber. Regarding the fixing belt, the physical properties described above were measured. The results thereof are shown in Table VI. Note that, in the table, the amount of X-33-174 added is indicated in terms of parts by weight relative to 100 parts by weight of silicone rubber.
TABLE VI
Refer-
Refer-
ence
ence
Exam-
Exam-
Exam-
Exam-
Exam-
ple 12
ple 13
ple 14
ple 6
ple 7
Type of rubber of
Sili-
Sili-
Sili-
Sili-
Sili-
elastic layer
cone
cone
cone
cone
cone
Filler
Type
SiC
SiC
SiC
Alu-
Metal
mina
Si
Vol. % X
50
50
50
50
50
CNT Vol. % Y
2
2
2
2
2
Hardness index:
506
506
506
506
506
10X + 3Y
Thermal conduction
210
210
210
210
210
index: 3X + 30Y
Fixing property
⊚
⊚
⊚
⊚
⊚
Hardness (degree)
24
24
24
20
24
Thermal conductivity
2.1
2.1
2.1
2.0
2.0
(W/m · K)
Additive
Type
X-33-
X-33-
X-33-
X-33-
X-33-
to elastic
174
174
174
174
174
layer
Amount of
0.5
1
3
1
1
addition
Adhesion(g/cm)
170
180
180
120
180
Durability test
⊚
⊚
⊚
◯
⊚
In Examples 12 to 14, the elastic layer 3 is formed using silicone rubber, and a rubber-based resin for primer use is further added thereto (corresponding to Claim 7 ). As is obvious from the results of Table VI, in Examples 12 to 14 in which the hardness index and the thermal conduction index are within the ranges of the present invention, an excellent fixing property is obtained. Moreover, adhesion among the base member 1 /primer layer 2 /elastic layer 3 and the result of the durability test are better than those of Example 5 in which the same conditions are used except that the rubber-based resin for primer use is not added. Consequently, the results of Table VI show that by forming the elastic layer 3 using silicone rubber and by further adding a rubber-based resin for primer use thereto, adhesion among the base member 1 /primer layer 2 /elastic layer 3 is improved.
Furthermore, in Reference Example 6 in which alumina is used as the filler and the other conditions are the same as those of Example 13, an excellent fixing property is obtained. However, as is obvious form comparison between Example 13 and Reference Example 6, in the example of the present invention (Example 13) in which SiC is used as the filler, thermal conductivity is better, and in particular, adhesion and the durability test are largely improved, indicating that by compounding SiC as the filler, adhesion among the base member 1 /primer layer 2 /elastic layer 3 is improved, and a fixing belt having excellent durability can be obtained.
In Reference Example 7 in which metal silicon is used as the filler and the other conditions are the same as those of Example 13, the fixing property, adhesion, and the result of the durability test are similarly excellent. However, as is obvious from comparison between Example 13 and Reference Example 7, in the example of the present invention (Example 13) in which SiC is used as the filler, thermal conductivity excels compared with the case where metal silicon is used.
Examples 15 to 17
A fixing belt shown in FIG. 1 was produced as in Example 5 except that silicone rubber (known silicone rubber having a methyl-type side chain) which is the same as the silicone rubber used for the elastic layer 3 was added to the primer layer 2 in the amount shown in Table VII. Regarding the fixing belt, the physical properties described above were measured. The results thereof are shown in Table VII. Note that, in the table, the amount of silicone rubber added is indicated in terms of parts by weight relative to 100 parts by weight of X-33-174A/B (rubber-based primer) constituting the primer layer 2 .
TABLE VII
Refer-
Refer-
ence
ence
Exam-
Exam-
Exam-
Exam-
Exam-
ple 15
ple 16
ple 17
ple 8
ple 9
Type of rubber of
Sili-
Sili-
Sili-
Sili-
Sili-
elastic layer
cone
cone
cone
cone
cone
Filler
Type
SiC
SiC
SiC
Alu-
Metal
mina
Si
Vol. % X
50
50
50
50
50
CNT Vol. % Y
2
2
2
2
2
Hardness index:
506
506
506
506
506
10X + 3Y
Thermal conduction
210
210
210
210
210
index: 3X + 30Y
Fixing property
⊚
⊚
⊚
⊚
⊚
Hardness (degree)
24
24
24
24
24
Thermal conductivity
2.1
2.1
2.1
2.0
2.0
(W/m · K)
Additive to
None
None
None
None
None
elastic layer
Amount of silicone
1
5
10
5
5
rubber added
Adhesion(g/cm)
170
180
180
120
180
Durability test
⊚
⊚
⊚
◯
⊚
In Examples 15 to 17, silicone rubber is added to the primer layer 2 (corresponding to Claim 8 ). As is obvious from the results of Table VII, in Examples 15 to 17 in which the hardness index and the thermal conduction index are within the ranges of the present invention, an excellent fixing property is obtained. Moreover, adhesion among the base member 1 /primer layer 2 /elastic layer 3 and the result of the durability test are better than those of Example 5 in which the same conditions are used except that silicone rubber is not added to the primer layer 2 . Consequently, the results of Table VII show that by adding silicone rubber to the primer layer 2 , adhesion among the base member 1 /primer layer 2 /elastic layer 3 is improved.
Furthermore, in Reference Example 8 in which alumina is used as the filler and the other conditions are the same as those of Example 16, an excellent fixing property is obtained. However, as is obvious form comparison between Example 16 and Reference Example 8, in the example of the present invention (Example 16) in which SiC is used as the filler, thermal conductivity is better, and in particular, adhesion and the durability test are largely improved, indicating that by compounding SiC as the filler, adhesion among the base member 1 /primer layer 2 /elastic layer 3 is improved, and a fixing belt having excellent durability can be obtained.
In Reference Example 9 in which metal silicon is used as the filler and the other conditions are the same as those of Example 16, the fixing property, adhesion, and the result of the durability test are similarly excellent. However, as is obvious from comparison between Example 16 and Reference Example 9, in the example of the present invention (Example 16) in which SiC is used as the filler, thermal conductivity excels compared with the case where metal silicon is used.
Reference Signs List
1
base member
2
lower primer layer
3
elastic layer
4
upper primer layer
5
surface layer | Provided is a fixing belt which has high thermal conductivity capable of achieving an excellent fixing property that can respond to the recent increase in printing speed, which has a proper degree of elasticity such that color toners are sufficiently enveloped so as to be melted and mixed, and which has excellent mechanical strength and durability. A fixing belt includes a tubular base member, an elastic layer disposed on the outer circumferential side of the base member, and a surface layer disposed on a surface on the outer circumferential side of the elastic layer, the fixing belt being characterized in that the elastic layer is composed of rubber into which a filler primarily composed of silicon carbide powder and a carbon nanotube are compounded, and the formulae 10X+3Y<750, 3X+30Y>170, X>10, and Y>0.1 are satisfied, where X is the percent by volume of the filler and Y is the percent by volume of the carbon nanotube in the elastic layer. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to mowers and, more particularly, to a mower having a cutting blade which retracts in response to an obstruction.
2. Brief Description of the Prior Art
U.S. Pat. No. 3,045,413 to Sheffer generally discloses a cutting blade and guard attached to a springed, laterally extending post. The cutting blade, guard, and post are supported by a hydraulic lever arrangement. The cutting blade is rotated by a motor, belt, and pulley.
U.S. Pat. No. 4,901,508 to Whatley generally discloses a fence row mower with a plurality of rotary blade units driven by a series of pulleys. Pressure cylinders are used to maneuver the plurality of rotary blade units.
In general, the known prior art must be supported or maneuvered by complex means, such as by pressurized fluid systems. This is expensive and adds to overall maintenance costs. Moreover, the prior art teaches using complicated blade drive units to rotate a cutting blade. Therefore, a need exists for a mower with a simplified cutting blade driver and a cutting blade that extends and retracts quickly from a utility vehicle without the need for complex fluid pressure systems.
SUMMARY OF THE INVENTION
In order to help satisfy the needs not currently met by the prior art, one embodiment of the present invention generally includes a mower adapted to follow terrain and retract in response to an immovable obstacle. The mower generally includes a utility vehicle, an attachment frame configured to be pivotally attached to one side of the utility vehicle, a secondary frame pivotally connected to the attachment frame, and a housing positioned adjacent to the secondary frame. The housing is preferably laterally movable with respect to the secondary frame via biasing means. In one method of operation, the housing retracts in a direction toward the secondary frame when contact occurs between the housing and the immovable obstacle and automatically returns to a pre-contact position when contact between the housing and the immovable obstacle is eliminated.
In sum, the present invention seeks to improve the mower art by providing a mower with an automatically biased cutting blade assembly. No hydraulic lifts or actuators are required to move the cutting blade assembly or to pivot the cutting blade assembly in response to uneven terrain. The cutting blade is directly attached to a vertical shaft, which in turn, is directly connected to a motor. When an immovable object, such as a fence post, is encountered, the automatic biasing action of the cutting blade housing helps to quickly and automatically return the cutting blade to a pre-contact position and significantly eliminates spots of uncut vegetation growing between adjacent fence posts.
These and other advantages of the present invention will be clarified in the description of the preferred embodiment taken together with the attached drawings in which like reference numerals represent like elements throughout.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top perspective view of a mower according to the present invention;
FIG. 2 is a top exploded perspective view of the mower shown in FIG. 1; and
FIG. 3 is a top plan view of the mower shown in FIGS. 1 and 2 .
DETAILED DESCRIPTION OF THE INVENTION
A mower 10 according to one embodiment of the present invention is generally shown in FIG. 1 . The mower 10 includes an attachment frame 12 configured to be pivotally attached to a utility vehicle 8 , a secondary frame 14 pivotally connected to the attachment frame 12 , and a cutting blade assembly 16 laterally movable relative to the cutting direction in the A 1 and A 2 directions with respect to the secondary frame 14 . The attachment frame 12 , secondary frame 14 , and cutting blade assembly 16 are preferably made from metal, such as steel or other suitable material, unless otherwise specified.
As shown in greater detail in FIG. 2, the attachment frame 12 is configured to be pivotally connected to a hitch 18 , which in turn, is rigidly connected to the utility vehicle 8 . In the preferred embodiment, the pivotal connection is acquired by aligning orifices O 1 defined by spaced apart pin receiving cylinders 20 positioned adjacent to a first frame member 24 of the attachment frame 12 , with corresponding orifices O 2 defined by second pin receiving cylinders 20 A attached to the hitch 18 and inserting pins 22 through the aligned orifices O 1 , O 2 . The combination of the spaced apart pin receiving cylinders 20 and the second pin receiving cylinders 20 A defines a first articulated joint.
In addition to the first frame member 24 , the attachment frame 12 further includes two, spaced apart second frame members 26 . Each of the two, spaced apart second frame members 26 have a first frame end 28 , with each first frame end 28 connected to the first frame member 24 . Each of the two, spaced apart second frame members 26 are preferably oriented perpendicular to the first frame member 24 .
A first wheel support 30 is generally positioned perpendicular to the two, spaced apart second frame members 26 and is preferably spaced away from and substantially parallel to the first frame member 24 . The first wheel support 30 can be a single bar or the spaced apart dual bar shown in FIG. 2. A first wheel 32 is positioned adjacent to a first support end 34 of the first wheel support 30 , and a second wheel 36 positioned adjacent to a second support end 38 of the first wheel support 30 . The first and second wheels 32 , 36 may be made from rubber or plastic and are preferably configured to roll in a direction coincident with an imaginary longitudinal axis L extending through the first wheel support 30 .
The secondary frame 14 is pivotally connected to the attachment frame 12 via second joint brackets 40 positioned adjacent to second frame ends 42 of the two, spaced apart second frame members 26 , pin holes 50 (discussed below), and pins 22 . This combination is herein defined as a second articulated joint. The secondary frame 14 generally includes two, spaced apart, C-shaped channel members 44 , each connected to a corresponding channel bar 46 . The two, spaced apart channel members 44 and corresponding channel bars 46 are connected to one another by a generally C-shaped retention bar 48 .
Each channel bar 46 defines the pin holes 50 discussed above and movement restraint pins 52 at a third end 54 and retention member posts 56 at a fourth end 58 . A third wheel 60 is positioned adjacent to the fourth end 58 of one of the two, spaced apart channel members 44 , and a fourth wheel 62 is positioned adjacent to the fourth end 58 of the other one of the two, spaced apart channel members 44 . The third wheel 60 and the fourth wheel 62 , which may be made from rubber, plastic, or other suitable material, are also aligned to travel in the same direction as the first wheel 32 and the second wheel 36 .
The cutting blade assembly 16 is laterally movable in the A 1 and A 2 directions with respect to the secondary frame 14 . The cutting blade assembly 16 generally includes a housing 64 , with the housing 64 preferably defining a circularly-shaped outer perimeter. A motor mount 66 is attached to a first top surface 68 of the housing 64 . Both the motor mount 66 and the housing 64 define a coincident motor shaft orifice 70 .
One or more rollers 72 are positioned along first and second opposing sides 74 , 76 of the motor mount 66 . The rollers 72 are each oriented to be received by a corresponding one of the two, spaced apart channel members 44 of the secondary frame 14 .
Second retention member posts 78 and movement restriction brackets 80 extend from a second top surface 82 of the motor mount 66 . A motor 84 is mounted to the second top surface 82 of the motor mount 66 , so that a vertical motor shaft 86 extending from the motor 84 extends through the motor shaft orifice 70 . A rotating cutting blade 88 is attached to a free end 90 of the vertical motor shaft 86 and secured to the vertical motor shaft in the conventional manner.
When the cutting blade assembly 16 is installed in the two, spaced apart channel members 44 via the rollers 72 , end caps 92 are installed to prevent the cutting blade assembly 16 from rolling out of the two, spaced apart channel members 44 .
Retention members 94 , such as compressible springs, are connected to the second retainer member posts 78 are positioned on the second top surface 82 of the motor mount 66 , and the retention member posts. 56 positioned at the fourth end 58 of each of the channel bars, 46 .
FIG. 3 shows a top plan view of the mower 10 described in FIGS. 1 and 2. In one method of operation, the attachment frame 12 is pivotally connected to one side of a utility vehicle 8 , such as a four-wheeled motorcycle or other suitable conveyance. The motor 84 is then engaged, causing the cutting blade 88 to rotate. As the utility vehicle 8 and mower 10 move in the A 3 direction, the rotating cutting blade 88 cuts a swath in vegetation.
As the utility vehicle continues to move in the A 3 direction, an imaginary point P 1 on an outer periphery 98 of the housing 64 preferably contacts an exterior surface 100 of a post 96 . Continued movement of the utility vehicle 8 in the A 3 direction causes the outer periphery 98 of the housing 64 to travel in a direction toward imaginary point P 2 , along arc length AL 1 . Assuming that the utility vehicle 8 maintains a constant distance from the post 96 , the cutting blade assembly is gradually forced in the A 1 direction as the relative position of the housing 64 , with respect to the post 96 , changes over time from the P 1 position to the P 2 position. Movement of the cutting blade assembly 16 in the A 1 direction is stopped if the movement restriction brackets 80 contact the movement restraint pins 52 .
Once the imaginary point P 2 on the outer periphery 98 of the housing 64 is approximately coincident with the post 96 , continued movement of the utility vehicle 8 in the A 3 direction preferably causes a second arc length AL 2 of the outer periphery 98 of the housing 64 to contact the exterior surface 100 of the post 96 in the P 2 to P 3 direction, over time. As contact between the exterior surface 100 of the post 96 and the second arc length AL 2 portion of the outer periphery 98 of the housing 64 continues in the P 2 to P 3 direction over time, and again assuming an approximate static distance between the post 96 and the utility vehicle 8 , the retention members 94 bias the cutting blade assembly 16 housing 64 against the exterior surface 100 of the post 96 . Once the housing 64 clears contact with the post 96 , which in this example would be approximately at imaginary point P 3 , the retention members 94 continue to automatically bias the cutting blade assembly 16 to its approximate pre-contact position with respect to the post 96 , greatly reducing the amount of vegetation which remains uncut between neighboring fence posts.
Another feature of the present invention is also shown in FIG. 3 . The first and second articulated joints discussed above allow the attachment frame 12 to pivot with respect to the utility vehicle 8 , and further allow the secondary frame 14 and the cutting blade assembly 16 to pivot with respect to the attachment frame 12 . This configuration allows the cutting blade 88 to adjust to non-planar terrain.
As discussed above, the present invention provides a non-complicated device for cutting vegetation between two or more inanimate objects. The cutting blade assembly of the present invention is automatically biased, so there is no need for complex fluid systems. Moreover, the cutting blade is attached to a vertical shaft motor, which eliminates the need for more complex pulley and belt designs. The present invention is also configured to automatically adapt to non-planar terrain, such as culverts or slopes, preferably via the first and second articulation joints.
The invention has been described with reference to the preferred embodiment. Obvious modifications and alterations will occur to others 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. | A mower suitable for attachment to a utility vehicle and adapted to follow terrain and retract in response to an immovable obstacle, the mower generally including an attachment frame configured to be pivotally attached to the utility vehicle, a secondary frame pivotally connected to the attachment frame, and a housing positioned adjacent to the secondary frame and being laterally movable with respect to the secondary frame, wherein the housing retracts in a direction toward the secondary frame when contact occurs between the housing and the immovable obstacle and automatically returns to an approximate pre-contact position when contact between the housing and the immovable obstacle is eliminated. |
REFERENCE TO RELATED APPLICATIONS
This application is a division of U.S. Ser. No. 10/610,042 filed Jun. 30, 2003 now U.S. Pat. No. 7,438,324.
BACKGROUND OF THE INVENTION
This invention relates to a unique reaming tool bit for use in repairing broken conduit.
Electrical conduit is often embedded in concrete foundations and floors of commercial and residential buildings, so that electrical wiring can be run at a later time. Since concrete foundations and floor are poured before any internal walls and other structures are erected, short sections of conduits extend vertically above the foundation and floor at every location of an electrical source. In large construction projects, there may be hundreds of exposed conduit ends extending from the concrete foundation and floors. In the course of construction, these exposed ends of the electrical conduit are often broken off by workers and equipment in the course of moving materials, erecting interior walls and other construction activities. The broken conduit ends must be repaired so that additional sections of conduit can be connected to them to complete the installation of the electrical systems.
More often than not, the conduit breaks off near the foundation. Consequently, repairing the broken conduit requires breaking up the foundation around the broken conduit end to expose the end so that a coupling can be attached over it. Once the coupling is connected to the exposed broken end, the concrete foundation is patched around the repaired conduit.
Repairing the broken conduit embedded in a concrete foundation is an expensive and time consuming project. A large construction site may have hundreds of exposed conduit ends broken over the course of the construction project. Repairing broken conduit ends is a time consuming expense that is not factored into the cost of most construction projects. Consequently, a method for quickly and easily repairing broken conduit ends is needed.
SUMMARY OF THE INVENTION
The method and specialized repair component for repairing broken conduit ends of this invention eliminates the need to break up the concrete foundation around the broken conduit end. The specialized repair components include a reaming bit for milling out and turning down the inside wall of the broken conduit end and repair couplings for joining a new section of conduit to the broken conduit end. The reaming bit is designed to be used with any conventional handheld power drill. The reaming bit mills out the inside of the broken conduit end so that the repair coupling can be inserted into the broken conduit end. With the coupling fitted into the broken conduit end, a new section of conduit can be connected completing the repair. Because the coupling is inserted into the broken end of the conduit instead of over it, the concrete foundation around the conduit does not have to be disturbed. Consequently, this repair method provides a structurally more secure repair.
Accordingly, an advantage of this invention is that the method eliminates the need to breakup concrete foundations surrounding the broken conduit end, which greatly reduces the time and expense of the repair.
Another advantage of this invention is that the repair method provides a more structurally secure repair because the concrete foundation remains undisturbed.
Another advantage of this invention is that the repair method requires only two specialized repair components: a reaming bit and a repair coupling.
Another advantage of this invention is that the reaming bit is designed to be used in any conventional handheld power drill, which is common and readily available at any construction site.
Another advantage of this invention is that a single user in only a few minutes can prepare a large number of broken conduit ends for repair, turning down the inside walls of the conduit with the drill mounted reaming bit.
Other advantages will become apparent upon a reading of the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention has been depicted for illustrative purposes only wherein:
FIG. 1 is a perspective view of the reaming bit used in the repair method of this invention;
FIG. 2 is an elevated side view of the reaming bit of FIG. 1 ;
FIG. 3 is an end view of the reaming tool bit of FIG. 1 ;
FIG. 4 is an exploded view of the reaming tool of FIG. 1 ;
FIG. 5 is a side view of the reaming tool bit mounted to the chuck of a conventional hand drill being inserted into a broken conduit end embedded in a concrete foundation (shown as a partial side sectional view);
FIG. 6 is a side view of the reaming tool bit mounted to the chuck of a conventional hand drill being withdrawn from the broken conduit end embedded in a concrete foundation showing the bored out inner wall of the broken conduit end (shown as a partial side sectional view);
FIG. 7 . is a side sectional view of one embodiment of the repair coupling of this invention being inserted into the bored out broken conduit end;
FIG. 8 is a side sectional view of the repair coupling of FIG. 7 connecting the repaired conduit end and a new section of conduit;
FIG. 9 is an exploded perspective view of a second embodiment of the repair coupling of this invention;
FIG. 10 is an exploded perspective view of a third embodiment of the repair coupling of this invention;
FIG. 11 is a side sectional view of the repair coupling of FIG. 10 connecting the repaired conduit end and a new section of conduit; and
FIG. 12 is a side sectional view of the repair coupling of FIG. 9 connecting the repaired conduit end and a new section of conduit.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment herein described is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is chosen and described to best explain the invention so that others skilled in the art might utilize its teachings. This invention entails a method of repairing broken electrical conduit embedded in a concrete foundation without breaking up the foundation and the specialized components used in the repair, namely, a reaming bit and various embodiments of a repair coupling.
FIGS. 1-4 illustrate the specialized reaming bit of this invention (designated generally as reference numeral 10 ), which is used to bore out the inner wall of the broken conduit end. Reaming bit 10 has a conventional design and construction common for drill and milling tools and is intended for use with hand held power drills (reference numeral 8 in FIGS. 5 and 6 ). As shown, reaming bit 10 includes an interchangeable cutting head 20 and pilot head 28 mounted on a mandrel 30 . It should be noted that the reaming bit could also be machined from a solid piece of metal stock (not illustrated in the figures) within the teaching of this invention. The multiple piece design allows interchangeable cutting heads of various sizes to be used with a standard mandrel assembly.
As shown in FIGS. 1-4 , cutting head 20 has a cylindrical body 22 and six helical cutting blades 24 . Cutting head 20 also has an axial through bore 21 , through which the mandrel extends. Each cutting blade has a cutting edge and a cutting face that allows the material shaved from the conduit wall to be expelled upward. The outer diameter of cutting head 20 is sized to mill out and remove material from the inner wall of the broken conduit end to reduce the wall thickness to accommodate the repair coupling. Generally, cutting head 20 is sized to remove approximately one half the thickness of the conduit wall. Pilot head 28 has an axial through bore 29 , through which mandrel 30 extends. Mandrel 30 has an integral cylindrical shoulder stop 32 and axial shank 34 that extends axially from opposite ends of the shoulder stop. As shown, cutting head 20 and pilot head 28 are mounted to the proximal end of shank 34 by a bolt 36 that is turned into a threaded axial bore 35 in shank 34 . The distal end of shank 34 is used to secure the reaming bit to the chuck of a power drill. A pin 38 extends through lateral bores in cutting head 20 and shank 34 to secure and prevent the cutting head from turning on the mandrel. The outer diameter of the pilot head 28 and shoulder stop 32 are sized to accommodate the inner and outer diameters of the broken conduit end, such that the pilot head is insertable into the broken conduit end and the oversized shoulder stop will abut against the conduit end.
FIGS. 7-14 illustrate different embodiments of the repair couplings of this invention, which are used to join the broken conduit end to a new section of conduit. The repair couplings join the broken conduit ends to new sections of conduit. Because electrical conduit is available in various standardized diameter sizes and wall thicknesses, the repair couplings of this invention are intended to be dimensioned into standardized sizes that accommodate the various diameter sizes and conventions of both plastic and metal electrical conduit. For example, different sizes of repair couplings will be used with each standardized diameter of the electrical conduit, i.e. 1 inch, ¾ inch, etc . . . . In addition, the teachings of this invention encompass variations in the repair coupling that will connect conduit of both identical (straight couplings) and differing diameter sizes (reducer couplings).
FIGS. 7 and 8 illustrate the repair coupling of this invention designated by reference numeral 40 . Repair coupling 40 has a single piece construction and is ideally formed from a plastic material, such as acrylonitrile-butadiene-styrene (ABS) or polyvinylchloride (PVC), but can also be cast from a metal such as brass, aluminum or steel. Repair coupling 40 has a tubular body with a larger diameter female end 42 and a smaller diameter male end 44 . Repair coupling 40 is dimensioned so that male end 44 can be inserted directly into the reamed conduit end with a snug fit and a new section of conduit can be inserted into the female end. As shown, the thickness the of sidewall of male end 44 are significantly thinner than the sidewall of female end 42 , and is approximately one half the thickness of the sidewall of the reamed conduit end in which it is inserted. For a ¾ inch sized repair coupling, the sidewall thickness at male end 44 is approximately 0.0640 inches (generally ranging between 0.0600-0.0700 inches) and the sidewall thickness at the female end is approximately 0.1260 inches (generally ranging between 0.1200-0.1300 inches). For a one inch sized repair coupling, the sidewall thickness at male end 44 is approximately 0.0675 inches (generally ranging from 0.0670-0.0680 inches) and the sidewall thickness at the female end is approximately 0.1425 (generally ranging from 0.1400-0.1500 inches). The tubular sidewalls of repair coupling 40 form a cylindrical passage therethrough. As shown in FIG. 8 , the inner diameter of female end 42 is slightly greater than the inner diameter of male end 44 , which forms a shoulder 46 . Shoulder 46 acts as a stop of the new conduit section.
FIGS. 9-12 illustrate another embodiment of the repair coupling of this invention (designated as reference numeral 50 ). Repair coupling 50 has a two piece component design that includes an inner sleeve 52 and an outer collar (designated as 60 in FIGS. 9 and 12 and 70 in FIGS. 10 and 11 ). Both the inner sleeve 52 and outer collar 60 and 70 may be formed from a plastic material, such as acrylonitrile-butadiene-styrene (ABS) or polyvinylichlioride (PVC), or cast from a metal such as brass, aluminum or steel. Again, repair coupling 50 is intended to be sized and dimensioned into standardize sizes that accommodate the various diameter sizes and conventions of both plastic and metal electrical conduit. Generally, inner sleeve 52 is constructed of plastic and outer collars 60 and 70 are constructed of metal and is a conventional conduit connector of standard size. Inner sleeve 52 has a generally tubular body with a smooth axial bore 53 . As shown in FIGS. 11 and 12 , one end 54 of sleeve 52 is dimensioned for insertion into the reamed conduit end while the other end 56 is dimensioned for insertion into one end of outer collar 60 or 70 . As shown, outer collars 60 and 70 differ only in that collar 60 has a threaded mouth 62 for receiving threaded electrical conduit 6 a ( Fig. 12 ), while collar 70 has a smooth mouth 72 for receiving non-threaded conduit 6 ( FIG. 11 ), such as EMT (electrical metallic tubing). A small screw 74 is turned into a threaded side bore 73 in collar 70 to secure the new section of conduit into the collar.
FIGS. 5-12 illustrate the various steps in the method of this invention for repairing the broken conduit end designated generally as reference numeral 2 embedded in a concrete foundation 3 . Often the broken conduit end extending from the concrete foundation is jagged and uneven and may extend some distance above the foundation. Initially, broken conduit end 3 is often cut at the surface of foundation 3 to provide a clean and straight end for repair, as shown in FIG. 5 . As illustrated in FIGS. 5 and 6 , reaming bit 10 is used to mill out the inside of the broken conduit end 2 . Pilot head 28 guides and centers cutting head 20 as a user inserts reaming bit 10 into broken conduit end 2 . The user inserts reaming bit 10 into the broken conduit end until shoulder stop 32 abuts the end of the conduit, whereby the rotating cutting head 20 reams out the inside of sidewall 4 to reduce the thickness of the conduit sidewall to a set depth substantially equal to the length of the cutting head. When reaming bit 10 is withdrawn from broken conduit end 2 , the inside of conduit sidewall 4 has been reamed out (turned down) to receive the repair coupling. Next, the repair coupling is fitted to the reamed conduit end 2 ( FIGS. 6 and 7 ). Typically, the male end of the repair coupling is hand pressed into the reamed conduit end and a joint compound is used to permanently join the repair coupling to the conduit. The last step, illustrated in FIGS. 8 , 11 and 12 is to connect a new section of conduit designated as reference numeral 6 in FIGS. 8 and 11 , and as 6 a in FIG. 12 to the repair coupling. Again a joint compound is typically used to join the new conduit section 6 while conduit section 6 a is joined by way of cooperating threads. Once the new conduit section is joined, wiring can be run within the repaired conduit system.
ADVANTAGES
One skilled in the art will note several advantages of this repair method and specialized repair components of this invention. The method eliminates the need to breakup concrete foundations surrounding the broken conduit end, which greatly reduces the time and expense of the repair. The repair method requires only the specialized reaming bit and a repair coupling. The reaming bit is deigned to be used in any conventional handheld power drill, which is common and readily available at any construction site. In a matter of minutes, a single user can prepare a large number of broken conduit ends for repair, turning down the inside walls of the conduit with the drill mounted reaming bit. The reaming bit is a relatively small component that can be carried by workers with little inconvenience. The repair method also does not require the repairer to carry any other additional tools.
The repair couplings are small, inexpensive piece parts, whose cost is significantly less than the cost of repairing a concrete foundation. The repair couplings are generally constructed from plastics and can be produced in various sizes in large quantities with great cost effectiveness. The single piece design of the first embodiment of the repair coupling is well suited for low cost plastic construction. The two piece design of the repair coupling of the second embodiment allows the combination of both plastic and metal conduit. Building codes often require metal conduit be run from the foundation up. Consequently, plastic conduit must often be mated with metal conduit at the foundation. The two piece design of the second embodiment allows plastic inner sleeves to be mated with plastic or metal collars. The repair coupling provides a convenient interconnection between the plastic conduit inside the foundation and metal conduit run above the foundation if required. In addition, the inner sleeves are designed to fit into conventional collars that are common and readily available in the industry further reducing costs.
It should be noted that the repair method of this invention also provides a more structurally secure repair. Patched concrete foundation never has the integrity of the original foundation and is subject to cracks, as well as an unsightly appearance. Consequently, eliminating the need to break up and patch the concrete foundations is a significant advantage of this repair method. While the inside of the sidewalls of the conduit are turned down, the concrete foundation, which is left undisturbed around the conduit end, provides sufficient structural support to the repair coupling and new conduit sections. Because the concrete foundation surrounds the broken conduit end, the turned down sidewall of the conduit is reinforced from outside forces that may fracture or crack the conduit.
It is understood that the above description does not limit the invention to the details given, but may be modified within the scope of the following claims. | A reaming tool for reaming a socket in a broken end portion of a cylindrical conduit enlarges the internal diameter of the broken end portion to provide a socket for receiving a male end portion on a repair coupling. The reaming tool is guided by the inner diameter of the conduit while reaming out the broken end portion to a socket diameter that is about midway between the original internal and outer diameters of the conduit. |
FIELD OF THE INVENTION
[0001] This invention relates to a system for updating and synchronizing a document on a network server from a remote device. More specifically, this invention uses the Document Object Model (DOM) specification to manipulate documents, including databases that conform to the XML document structure specification, to enable remote workstations, or clients, to update a database on a server. Because the invention performs the update through the transmission of the minimum amount of information necessary to fully update the server's database, it is suitable for applications, including wireless transmissions, transmissions in which the connection between the client and server is of limited bandwidth, transmissions using conventional telephone lines, and transmissions through computer networks using physical media.
BACKGROUND OF THE INVENTION
[0002] In modem business and industrial applications, it is imperative that critical databases be updated and synchronized frequently and regularly to ensure the accuracy of their information. It is common for entire offices and buildings to be devoted to personnel whose primary task is to enter data into a database in the form of additions of new data, deletions of old data, or modifications of existing data. The data is entered from workstations (“clients”) that are networked with a server upon which the main database resides. Each change to the data is transmitted to the server, which will temporarily lock the record from access by other users, make and save the change, and then unlock the record so that it may be accessed by other users. This process is repeated countless times during the course of a normal workday, each change requiring essentially the same steps to be taken. When the server and its clients are directly connected over a large bandwidth connection, the overhead that may be inherent in multiple changes being made to the same record may not be detrimental to the overall throughput of the system. However, when the server and its clients must communicate over narrow bandwidth channels, the possibility for congestion to detrimentally affect system performance is significantly greater. The degree of congestion rises with the size of the database, the number of entries needed to keep it current, and the frequency with which accesses to the database are made.
[0003] The advent and increasing prevalence of wireless communications has made it possible for databases to be maintained and brought current from remote sites. Using wireless technology, critical databases can be maintained in a near-current state from cellular telephones, hand-held devices, and personal data assistants (PDA's), regardless of where they may be located. Common uses for such technology may be found in the maintenance of personal and business calendars from PDA's that are remote from the server where the organization's entire calendar is maintained, sales automation and inventory management, and similar applications. Uses for such technology could involve a customer's use of a handheld device to register purchases in a supermarket; automated closeout of a car rental upon return of the vehicle without the need for human oversight; or position tracking for vehicles and aircraft based, not upon a radar/transponder reflection, but upon the vehicle's own report of its position from global satellite positioning data. Virtually every database application in which timely and accurate information updating is critical is subject to remote data entry that may rely upon wireless communications.
[0004] A primary drawback for such applications is that the bandwidth available for database updates from remote clients may be limited. As wireless devices become more prevalent, the availability of bandwidth for each application and user will diminish, resulting in transmission bottlenecks, communications delays, and ultimately, the untimely update of project-critical information. Since common wireless applications such as cellular telephones and wireless Internet PDAs are commonly assigned narrow bandwidths, there is a need for a system that will reduce the number of accesses from client to server and that will require the transmission of only the smallest amount of data that is necessary to provide complete information for the server to update its database. The concept of sending only the smallest amount of information needed to perform the update is known as “granularity.” In general, a finer granularity results in a more efficient the use of the available bandwidth.
SUMMARY OF THE INVENTION
[0005] The present invention is a system that resides on the remote client, and which notes and records the accumulation of mutations (additions, deletions, modifications) to the client's local database, which normally will constitute a subset of the main database that resides on the server. Before changes to the local database are transmitted to the server, they are processed and reduced to the smallest amount of data, or the finest granularity, that will allow the server to record the changes to the main database. The system uses XML (extensible Markup Language) documents to represent the local database, and further uses the DOM (Document Object Model) established by the World Wide Web Consortium (W3C), to provide a standardized interface for manipulation of the XML document. Although the specifications for the DOM and the XML are currently undergoing a process of development and refinement, the implementation of those specifications in this invention is not intended to be version-specific, but is generic and should perform effectively with future versions of those specifications as well as with all existing versions.
[0006] In XML, a “document” may represent a collection of related data, including a database. In the DOM specification, an XML document may be represented as a logical “tree” having objects, or “nodes,” located in a hierarchical branching structure. Each node has various properties, including at least a “name” (or “label”) property, and a “data value” property. Each discrete data element in the XML document can be identified by an XML tag, and the DOM will have a node corresponding to each such data element. When data in the XML document is added, deleted, or modified, the DOM also changes to reflect the modification. The automatic modification of the DOM to conform to the XML document is a property of the DOM specification and its implementation. Mutations to the XML document are recorded in an Event Table as “events.” All events are stored, cross referenced to the path of the node, a timestamp, and the mutation type. When data synchronization occurs, the Event Table is parsed, and each node at which multiple events took place is collapsed to a single event using a set of rules described below. The data value of such collapsed node is the value left by the last mutation involving the node. By collapsing the number of node events in the DOM after modifications have been made to the document, the data necessary to update the main database is brought to a minimum, and may then be transmitted to the server for application to the main database.
[0007] The process of collapsing the number of node events requires a sorting, followed by the parsing of each event in the Event Table whereby events to be passed to the remote database will be saved in a Save Table, while redundant events are discarded. When the Save Table has been created, a synchronization manager will then retrieve data from each node referenced in the Save Table, and the data for each event in the Save Table will be transmitted to the main database along with the node address, an optional date stamp, and the event type.
[0008] Accordingly, it is an object of the present invention to provide a system for tracking changes made at a workstation to a subset of a database and, before sending the changes to the server, to reduce to a minimum the amount of a information that must be sent. It is a further object of this invention to increase the efficiency of database updates over narrow bandwidth communication channels. It is another object of the invention to utilize the XML and DOM specifications to process data on a remote client using a standardized format for reducing the amount of information necessary to fully describe the changes to the database. These and other objects of the invention will become evident through the following description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] [0009]FIG. 1 is a flow chart depicting the flow of events through a remote client prior to transmission to a server for entry into a database.
[0010] [0010]FIG. 2 a shows an example in which the local database is an address book.
[0011] [0011]FIG. 2 b shows a logical representation of the address book in the format of an XML document.
[0012] [0012]FIG. 3 a lists hypothetical changes that are made to the address book.
[0013] [0013]FIG. 3 b shows the hypothetical changes to the address book as they are recorded in the Event Table.
[0014] [0014]FIG. 4 shows the Event Table after it has been sorted and before it has been parsed.
[0015] [0015]FIGS. 5 a and 5 b are connecting sections of a flow chart depicting one embodiment of the decision-making process that will reduce the number of events that will be sent to the main database. In FIGS. 5 a and 5 b, the Event Table has been sorted, but has not yet been parsed.
[0016] [0016]FIG. 6 shows the Save List for mutations made to the hypothetical address book of FIGS. 2 - 4 .
[0017] [0017]FIG. 7 is a DOM representation of the XML document of FIG. 2 b prior to changes having been made.
[0018] [0018]FIG. 8 is the DOM representation of the XML document representing the hypothetical address book after changes have been made to the address book.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] As is shown in the flow chart of FIG. 1, changes made to a local database 100 are registered as “events” by Event Listener 110 . In the XML-DOM specification, as applied in the invention, an event occurs whenever a node is added or deleted, or the data in a field is modified. In FIG. 1, events 120 are detected at Event Listener 110 and passed to Change Manager 130 where they are listed as records in Event Table 300 . When modifications to the XML database have been completed, the Change Manager 130 parses Event Table 300 to determine which nodes in the DOM tree are affected by the events listed in the Event Table. The parsing creates a second list of changes (the “Save Table”) to be transmitted to the computer on which the main database resides which, when applied to the main database, will update that database with the remotely-performed changes, thus keeping the client and server data in synchronization. This second list represents the smallest number of modifications that must be made to fully update the database resident on the server. The Save Table may be compressed with any commercial compression product for transmission to the server where the database will be modified in accordance with data received from the Synch Manager.
[0020] In FIG. 2 a, an example is shown using an address book as the local database 200 . It will be understood, however, that this invention is not limited to this exemplary implementation, and that any document capable of being formatted as an XML document having a DOM representation, and subject to multiple modifications made from a remote terminal, will fall within the scope of the invention. In this example, the address book may constitute a subset of a larger organization-wide address book maintained on the server. The local address book has three fields: “Name” 210 , “Phone” 220 , and “E-Mail” 230 . Three records are in the address book, and the manner in which the system of this invention updates the organization-wide address book with changes made to the records shown in FIG. 2 a will be described.
[0021] [0021]FIG. 2 b shows the address book represented as an XML document. In the XML specification, a “document” may constitute almost any object having properties that include a value. The XML structure reflects the organization of the database. Thus, the XML tag <address book> 250 , represents the database, and is located at the highest level. Each database record 260 , defined as a “person,” is located at an intermediate level, and has a unique ID attribute that uniquely identifies it and distinguishes it from other elements at the same level. Discrete data elements representing the data in each field of each record are located at the lowest level. In FIG. 2 b, the XML tag <person ID=“1”> 260 is at the intermediate level, while data maintained under the XML tags for <name> 270 , <phone> 280 , and <email> 290 are located at the lowest level.
[0022] The DOM presents documents as a hierarchy of “node” objects. The DOM corresponding to the XML document of FIG. 2 b is a branching hierarchy, as depicted in FIG. 7. The DOM may include a variety of node objects that also implement other, more specialized interfaces for accessing and manipulating document objects. Some types of nodes may act as “parent” nodes having “child” nodes below them in the hierarchy. Others may be “leaf” nodes that cannot have anything below them in the document structure. Each node in the DOM corresponds to an XML tag. Each node has properties, including at least a “name” property and a data value property. As shown in FIG. 7, node 411 is an “element” type object, and has a name property (“Person”) and an ID attribute 530 of “1.” The node is a parent-type node established in the DOM specification. Nodes 414 - 422 with them. However, for each sub branch of the DOM, the element name property for each element will not be repeated in that sub branch. Nodes 422 - 431 are leaf “text” nodes and cannot have child nodes below them. A text node contains only a data value and is associated with an element node. For example, node 416 is the element node having the property “phone,” and node 425 is the associated text containing the data “ 617 - 321 - 7654 .” Another example is shown at nodes 418 and 427 having the element “email,” and a data value of “[email protected].”
[0023] Mutations are made to the local database by adding, deleting, or substituting data elements in the XML document. Example changes to the address book are shown in tabular form in FIG. 3 a, while FIG. 3 b shows an Event Table that corresponds to those changes. The Event Table has fields that loosely correspond to the fields of the address book. Thus, for example, the “Event” column 340 of the address book, which identified objects undergoing a change, corresponds to the XQL path 310 to the node in the DOM at which the object that was the subject of the event is located; the “Change” column 350 of the address book describing the change corresponds to the “Nature of Event” field 320 (whether the event was a record addition or deletion, or a field modification) in the Event Table; and the “Time” column 360 describes the time the change was made to the address book, and corresponds to the “Time” field 330 in the Event Table. Although each instance of change in the database is recorded in the Event Table, specific data that is added, deleted, or substituted is not so recorded. Rather, once the Event Table has been processed and the number of events has been reduced to a minimum, the Change Manager will retrieve the relevant data values from the DOM to pass to the Sync Manager for transmission to the server. Each addition, deletion, or modification of data in the address book will cause a new record to be added to the event table until the synchronization process begins. Following synchronization, the data in the Event Table is cleared and new data will be added as further mutations are made to the local database.
[0024] When a new record is to be added to the local database, only such information as is needed to update the main database will be saved and transmitted. For example, in FIG. 3 a, it will be seen that a new person, “Carol Roe” is being added to the address book 372 . In order to minimize storage space on the client, Add the default method for adding a new record to the local database will not add either element or text nodes that are currently not being used. Therefore, neither element nor text nodes are added at event 372 . A node that exists in the XML Document Type Definition (DTD), but not in the DOM tree, represents a null node value. Thus, when a new record is to be added to the address book, initially only a new “person” element is added. Thereafter, when a name 373 , phone 342 , or email 375 is added to the address book, the corresponding child element and text nodes will be added to the Event Table, 383 , 384 , and 385 , and to the DOM.
[0025] The DOM of FIG. 7 depicts parent-child relationships between the nodes as a static, solid connecting line. However, the DOM structure is a “live” construction, meaning that it is constantly changing to reflect the contents of the XML document in real time as the document is modified. In FIG. 7, the DOM shows the address book as it exists in FIGS. 2 a and 2 b, before any of the changes shown in FIGS. 3 a and 3 b have been made. Each node has a name property, a data value property, and a type property. The type properties of the DOM describe the type of node. The Worldwide Web Consortium (W3C) has defined the basic element, text, attribute, and document node types. The name properties of the DOM in this example have been selected to be descriptive of the nodes. In FIG. 7, the DOM has a root node 410 of type “Document” having the name property (“address book”), but has no data value. Three “Element” type nodes 411 - 413 are situated immediately below the document node and have the name property “person”. Each person “element” node has an attribute node of name “ID” and a value to uniquely distinguish it from every other person “element” node. Each person “element” node has three child “element” nodes, corresponding to the data in each of the database fields “name,” “phone,” and “email” for the relevant record. Text nodes 423 through 431 in FIG. 7 represent the data values for the parent “element” nodes.
[0026] In accordance with the DOM specification, nodes may be interfaced and manipulated with the methods that are applicable to each type of node. Although the DOM specification defines many such node types, the only nodes represented in FIG. 7 correspond to document, element, attribute, and text nodes. Returning to FIG. 1, changes made to the local database are implemented as changes to the XML document 100 representing the address book, and trigger events 120 that are detected by the Event Listener 110 and passed on to the Change Manager 130 . The Change Manager creates and manages the Event Table 300 in which all events occurring after the most recent synchronization are listed. The address book shown in FIG. 3 a and the Event Table shown in FIG. 3 b each list eight events reflecting changes in the local database. Changes to the address book are identified at 370 - 377 , while corresponding records entered into the Event Table are identified at 380 - 387 . At 370 it may be seen that David Doe changed his phone number. That event is reflected in the Event Table as an XQL path identifying the “phone” node for the person having ID=“2” 380 and a “change” of data. Next in the list, Sally Jones changed her e-mail address 371 , which corresponds to event 381 in the Event Table. A new, null record 372 was added to the address book to create a record for Carol Roe, and is shown in the Event Table at 382 . Carol's name 373 , phone 374 , and e-mail 375 are added in the address book, and correspond to events 383 , 384 and 385 in the event table of FIG. 3 b. Next, David Roe is removed from the address book 376 , and this event is shown as a deletion 386 in FIG. 3 b. Lastly, Carol Roe changed her phone number 377 , and this modification is shown in the Event Table at 387 . This is the last event before the changes will be processed, and the database on the server will be brought into synchronization with the modified data in the client address book.
[0027] The Change Manager determines which data must be passed to the server through a process of sorting and parsing the Event Table, and referring to the modified DOM to obtain the data related to each event in the Save Table. This process may follow any one of a number of methods for obtaining relevant data, and the steps outlined here are exemplary only, and do not represent the only means for obtaining such data. Regardless which method the Change Manager applies, however, it will produce the minimal change set needed to bring the server database into synchronization with that of the client.
[0028] In the embodiment depicted in FIGS. 2 and 3, the Change Manager will first sort, and then parse the Event Table to generate the minimal amount of data needed to send to the server. One method for doing this is to sort the Event Table by the XQL (structured query language for XML) path and timestamp. When sorted in alphabetical and timestamp order, the Sorted Event Table will place all events related to the same node consecutively in the table, and will place the earlier occurring events first. In this fashion, a node that has been added and later modified will appear in the table with the ADD event being above any subsequent MODIFY or DELETE events pertaining to the same node. A modified XQL is sorted alphabetically to group together all child nodes and branches, regardless of their location in the Event Table. FIG. 4 shows the address book example of FIG. 3 b after it has been sorted alphabetically and by timestamp.
[0029] All events in the Event Table 300 begin with the XQL path prefix “//person[@ID=”, such that the remainder of the XQL path will determine the listing order. As is shown in FIG. 4, person element nodes having an “ID” value of “2” are grouped together ( 380 with 386 ) followed by the sole person element node having an “ID” value of “3” ( 381 ). The largest grouping is of person element nodes having an “ID” of “4” ( 382 , 383 , 384 , 385 , and 387 ). Within each grouping, the shortest XQL path will have sorted to the top of the group, while progressively longer XQL paths will appear lower in the group listing. In order for the alphabetical sorting to work, the XQL path may be slightly modified by adding a special character to the beginning of the element name, which will cause the element to move to the bottom of the alphabetical list when sorted. After sorting, the shortest XQL path will correspond to the highest parent node of a branch, as with nodes at 382 and 386 , and will appear at the top of a grouping in the table. Next will be individual elements that do not have child elements, such as nodes 383 - 385 . Last will be nodes that have further child nodes, although none are depicted in the example of an address book. A deep node will have a long XQL path, but the path includes information about its parent nodes and will be sorted appropriately. After being sorted, the Event Table of FIG. 3 b will have all of the events in order, as shown in FIG. 4. The Change Manager will then parse the list to determine which events should be entered in the Save Table.
[0030] As depicted in FIGS. 5 a and 5 b, the Change Manager follows a set of rules to determine the minimal set of data to send to the server. Other embodiments may follow the same general steps and fall within the scope of this invention, yet differ in the specific manner in which they accomplish the steps. While other processing methods and steps may be used, one specific embodiment of the process is set forth in FIGS. 5 a and 5 b.
[0031] The general process for generating the Save Table involves a comparison of two events, denoted as Event A and Event B, which are designated as consecutive events in the sorted Event Table. Certain cases, however, require that save decisions be based upon the analysis of a single event, such as when the Event Table includes only a single event, or when there is but a single event remaining to be processed. The condition in which there is only one event in the Event Table will be detected at 600 , where an End of File flag will cause processing to follow steps shown at 610 - 650 . If the single event is an ADD 610 , then that event will be entered in the Save Table 630 as an ADD, and processing will end 650 . If the single event is a MODIFY 620 , then that event will be entered in the Save Table 635 as a MODIFY, and processing will end 650 . If the single event is a DELETE, then the event will be entered as a DELETE event 640 , and processing will end 650 .
[0032] Where the Event Table includes two or more events, processing will proceed to 660 , where the next event (a B event) will be compared with event A. If A and B have the same path 670 then A can only be an ADD or a MODIFY, while B can only be a MODIFY or a DELETE. If B is a MODIFY 680 , then A is kept and B is skipped or discarded 700 . If B is a DELETE, then the “Delete Flag” (DF) is set to “True” 690 , and A is kept while B is discarded 700 . Next, the EOF flag 710 is checked and, if the end of file has been reached, the process for handling a sole remaining event will be followed, as is described below. If there is another event in the Event Table, a new event will be retrieved as a B event 730 , and the comparison process will recommence 660 .
[0033] If A and B do not have the same path 670 , they will next be checked to see whether B is a subset of A 740 , that is, whether B falls along a path that is a sub branch of the path upon which A is located. If B is a subset of A, the process next determines whether A is an ADD 750 . If it is, the process determines whether B is also an ADD 760 . If both A and B are ADDs, the process next determines whether the DF (delete flag) is True 770 . If the DF is True (DF is set), then A is kept and B is discarded 700 , and the process checks for another event 710 . Alternatively, if the DF is False 770 , then A is saved as an ADD and B becomes the next A 790 , and the EOF 710 is checked.
[0034] If A is an ADD and B is not an ADD 760 , then B must be a MODIFY. The reason that B is a MODIFY, and cannot be a DELETE is that a child “element” node representing a name, an e-mail, or a phone, cannot be deleted independently, but can be deleted only as part of the deletion of its parent “person” element node. While the deletion of the parent node is recorded as an event, the deletion of child nodes below the parent are not written as events in the Event Table. Having determined that B is a MODIFY 760 , the process will next check the DF 780 . If the DF is True (set), A is kept 700 , B is discarded, and a next event is looked for 710 . If the DF 780 is False (not set), then A is added to the Save Table as an ADD 790 and event B becomes event A for purposes of the next comparison.
[0035] A similar process is followed if B is a subset of A 740 , and A is not an ADD 750 , but is a MODIFY 800 . If B is an ADD 810 , then the DF flag is checked 820 and, if True, A is kept 700 and B is discarded. If the DF is False 820 , then A will be saved as a MODIFY 795 and B will become the next A. If B is not an ADD 810 , then it must be a MODIFY, and the DF is checked 830 . If the DF is True 830 , then A will be kept 700 and B will be discarded. If DF is False, then A will be saved as a MODIFY and B will become the next A 795 .
[0036] If B is a subset of A 740 , and A is not an ADD 750 or a MODIFY 800 , then A must be a DELETE. Because of the manner in which the Event Table is sorted, it is possible that A may be a DELETE while B is an ADD or a MODIFY. Regardless whether B is an ADD or a MODIFY, the processing will result in A being kept 700 , and B being discarded. This result flows from the fact that, if A is DELETED, any nodes below it in the same branch will necessarily also be deleted and will not require processing.
[0037] When all but the last event in the Event Table have been processed, an EOF flag 710 will signify that there are no other events to be retrieved. There will be a single remaining A event that must then be processed. If that event is an ADD and the DF is False 900 , then it will be saved as an ADD 630 . If the A is an ADD and the DF is True 900 , then A will be saved as a DELETE. If A is not an ADD, it is then checked to see whether it is a MODIFY 890 . If it is a MODIFY and the DF is False 910 , then A will be saved as a MODIFY. If the DF is True 910 , then A will be saved as a DELETE. If A is neither an ADD 880 nor a MODIFY 890 , then it will be saved as a DELETE 640 . Once the event has been saved, processing of the Save Table terminates 650 and the Synch Manager 140 will retrieve data values from the DOM corresponding to ADD and MODIFY events in the Save Table.
[0038] Turning next to FIG. 5 b , processing of events is shown where the XQL paths for A and B are not within the same sub branch. In general, where the paths are different, the process will Save event A and will move event B to A and retrieve the next event as B. Because the B event represents a path that is different from that of A, the result of processing will leave the DF flag clear (False), will save the A event, and will move the B to the A event.
[0039] Thus, if A is an ADD 910 , then DF 920 is checked and, if True, the DF flag is cleared (set to False) 930 and A is saved as a DELETE 940 and event B becomes event A. Processing then proceeds to check for an EOF condition 710 , and further processing takes place as shown following EOF 710 in FIG. 5 a. If DF 920 is False, A will be saved as an ADD 950 and event B becomes event A.
[0040] If A is a MODIFY 960 , then DF 970 will be checked and if it is False, A will be saved as a MODIFY 980 . If DF 970 is True, A will be saved as a DELETE 940 . In either case, event B then becomes the next event A.
[0041] If A is not a MODIFY 960 , then it must be a DELETE and A will be saved as a DELETE while B becomes the next A 940 . The DF will be cleared 930 , and processing will continue with a check for the EOF 710 .
[0042] These decision rules shown in FIGS. 5 a and 5 b may be followed through the Sorted Event Table of FIG. 4 to result in the Save List shown in FIG. 6. The Change Manager will retrieve the first event [ 386 ], which is a DELETE event, will designate it as a A event, and will check to ensure that there is more than one event 600 . The Change Manager will next retrieve 660 the B event [ 380 ], which is a A MODIFY event [ 380 ]. At step 670 , the Change Manager determines that the a events do not have the same path 670 . Proceeding to step 740 , the Change Manager determines that B is a subset of A 740 , then determines that A is not an ADD 750 or a MODIFY 800 . The Change Manager then keeps (but does not yet save) A as a DELETE 700 , discards B, and retrieves 660 the next B event [ 381 ].
[0043] B event [ 381 ] is a MODIFY that is not a subset of A. The Change Manager proceeds to determine that A is not an ADD 910 and is not a MODIFY 960 . The Change Manager then clears the DF 930 , saves A as a DELETE, and moves B to A 940 . It then retrieves a new B event 660 , which is an ADD event [ 382 ] that is not a subset of A. Proceeding to steps 910 and 960 , the Change Manager determines that new event A [ 381 ] is a MODIFY 960 . The DF is False 970 , A is saved as a MODIFY and B becomes new event A 980 .
[0044] The next B event [ 385 ] is an ADD that is determined to be a subset of event A [ 382 ] at step 740 . Both A and B are ADDs 750 and 760 , and the Change Manager next checks DF 770 . Since DF 770 is clear, event A is saved as an ADD and event B moves to be new event A.
[0045] The next B event [ 383 ] is an ADD that is on a different sub branch from event A[ 385 ]. The Change Manager will process event A at steps 910 and 920 , and will save event A as an ADD 950 . Event B becomes new event A 950 , and the next event in the Sorted Event Table [ 384 ] is retrieved. This, too, is an ADD that is on a different sub branch, and processing at steps 910 and 920 will cause event A to be saved as an ADD and event B to become new event A 950 .
[0046] The change manager will then retrieve the last event [ 387 ] in the Sorted Event Table as a B event, and will determine that it has the same path as event A 670 . Since A is an ADD and B is a MODIFY 680 , A will be kept and B will be discarded 700 . Upon checking EOF 710 , the Change Manager will determine that no further events remain to be retrieved, and processing will continue at step 880 . Since event A is an ADD, and the DF is not set 900 , A will be saved as an ADD 630 , and processing of the Sorted Event List will terminate 650 . At that time, the Save List is complete and ready for transmission to the server.
[0047] [0047]FIG. 6 shows the Send List after it has been alphabetically sorted and then processed by the Change Manager. Comparing the list of FIG. 6 with that of FIG. 4, it may be seen that two changes made to the XML document need not be sent to the database on the server, and that the Send List represents the least amount of data that will synchronize the database on the server to that on the client device.
[0048] [0048]FIGS. 7 and 8, respectively, provide a depiction of the DOM before, and then after modifications were made to the address book. In FIG. 7, the DOM shows three elements 411 , 412 , and 413 , each of which is identified by a tag (“ID”) 520 , 530 , and 540 , having a different value. Each of the three records has three data elements: Name, 414 , 417 , and 420 ; e-mail, 415 , 418 , and 421 ; and phone, 416 , 419 , and 422 . The values of the data elements are shown, 423 - 431 , and the DOM tree of FIG. 7 provides a complete picture of the address book.
[0049] In FIG. 8, modifications have been made to the address book, and the DOM, which is a “living” object that reflects changes as they are made in real time, has been modified to reflect those modifications. In FIG. 8, the element 412 having an “ID”=“2” 520 has been deleted, as is symbolized by the dashed line separating that element from the DOM. Although an earlier modification was made to the telephone number for that element, the modification was later subsumed by the deletion of the entire record.
[0050] In addition, modifications made to the element having an “ID” of “3” are seen at 430 , in a modification of the e-mail address for that element. Lastly, the addition of a new element 510 having an “ID” of “4” 550 is shown in the DOM of FIG. 8. The data values existing in the DOM at the time of synchronization will all be obtained at one time and sent to the server, along with the Save Table for inclusion in the database residing on that server.
[0051] A further aspect of the invention may require the server to send updated information from its database to the client's local database for processing. This could occur, for example, when a single master database receives updates from more than one source. The processes of this invention may be employed at the server to reduce the amount of data that must be transmitted before the transmission to the client is performed. Potential conflicts that may occur when the same record is updated from two remote sites prior to synchronization may be handled by methods and processes known in the art.
[0052] It will be understood that the invention is not limited to the processes shown and described, which are exemplary, and that other uses and configurations may be employed that will fall within the spirit and scope of the invention. For example, although the processing steps have been described with reference to an alphabetized and time sorted event list, an alternative embodiment would be to sort each group of identical XQL paths to place all DELETE events ahead of all ADD or MODIFY events in the list, thereby eliminating some of the steps required to process the sorted list. Similarly, other schemes for sorting the list or reducing the amount of data that must be transmitted to the server to a minimum may be employed, which may be considered to fall within the scope of this invention.
[0053] While the invention has been described, disclosed, illustrated and shown in various terms or certain embodiments or modifications which it has assumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended. | In a system comprising a local processing device, a transmission link to a remote processing device, and a remote processing device, a method for updating a remote document in accordance with mutations made to a portion of the remote document maintained on the local processing device comprising the steps of loading at least a portion of the remote document into the local processing device as a local XML document, creating a logical document object model (DOM) having a plurality of nodes arranged in a logical hierarchical structure such that each node corresponds to an XML tag and data element in the XML document, mutating the XML document by adding, deleting, or modifying one or more of its data elements, updating the DOM to conform to the mutations to the XML document, creating a first event table that contains events corresponding to each mutation to the XML document where each entry comprises a path to a node in the DOM affected by the mutation and an event type, processing the first event table to create a second event table that contains the smallest number of events necessary to update the remote document to conform to the local XML document, transmitting the second event table and related data from the local device to the remote device, and mutating the remote document in accordance with events in said second event table and related data such that said remote document will have corresponding data elements of the same value as mutated data elements in the modified local XML document. |
TECHNICAL FIELD
[0001] The invention relates to electric drills with a quasi-circumferential workpiece lighting structure for lighting visible portions of the work area.
CROSS REFERENCE TO RELATED APPLICATIONS
[0002] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] Electrically powered drills remain one of the mainstays of every tool box, whether it be that of the homeowner or construction professional. Even going back to the 1950s, electrical drills were in very common use in the home, with companies like Sears Roebuck & Co. and others turning out high quality products at modest prices in what was then a very old technology.
[0005] Indeed, the most modern form of the electric drill, that is a pistol shaped device with a multi-fingered chuck that could be tightened using a conical gear key, followed closely the development of these chucks by the Jacobs Manufacturing Company in or about 1902. Except for the introduction of a switch to reverse drive direction and the introduction of rechargeable batteries in recent years, the technology remains essentially static.
[0006] While they have been available on the market for many years, about 20 years ago, electric powered drills and other tools came into prominence. Because the structural aspects of these tools which performed directly the work for which they are intended differed from earlier tools only by the substitution of battery power, designs largely emulated conventional tools powered by house current.
[0007] While the completion of battery power is a primary issue in battery powered drills, workpiece illumination lights have been employed in battery powered drills. In the case of tools, such as soldering irons, lights are also employed. Because these devices are always attached to house current, the lighting mechanism can consume relatively high power and deliver large amounts of light. Because of the nature of light sources, this light tends to be somewhat randomly spread about and results in somewhat effective illumination of the workpiece. Generally, such lights are positioned at a point around the circumference of the chuck aligned with the handle of the drill.
[0008] Prior art electric drills, such as the electric drill illustrated in U.S. Pat. No. RE 38,729 also use light sources. In the case of U.S. Pat. No. RE 38,729, two light sources are located on the sides of the drill, in other words, at ninety degrees to the handle of the drill.
SUMMARY OF THE INVENTION
[0009] In accordance with the invention, it has been recognized that drills often lose their charge for reasons unrelated to the amount of work being done. For example, it has been recognized that in many circumstances, drills are operated to perform a task but are positioned improperly, requiring that the work be repeated. Worst than that, sometimes a new workpiece needs to be obtained and this involves waste of workpieces and the materials from which they are made with consequent loss of any labor which has been expended to make the same. Added to this is associated environmental damage.
[0010] In an effort to address these problems, prior art electrical drills may be provided with a light. Generally, this has involved the use of a light emitting diode which may extend from the body of the electrical drill. Alternatively, the prior art shows the use of a light emitting diode which is recessed inside the drill. Typically, the light emitting diode is aimed at the place where the drilling or other operation, such as tightening or unscrewing of a screw, is done.
[0011] In accordance with the invention, high efficiency in lighting is provided by illuminating principally those areas of the workpiece which are likely to be visible to the user of the tool and/or likely to need illumination.
[0012] Importantly, as has been recognized in accordance with the invention, the positioning of lights aligned with the bottom of the drill and its handle suffers from the inefficiency of not illuminating that portion of the workpiece adjacent the top of the drill, i.e. that portion of the workpiece opposite the handle. Since the most visible part of the workpiece is that portion of the workpiece adjacent the left side of the drill in the case of a right-handed user and adjacent the right side of the drill in the case of a left-handed user, and the second most visible part is that portion of the workpiece opposite the handle, maximum efficiency of illumination and provision of the tool which will work well for both right-handed and left-handed users is served by the provision of lighting on opposite sides of the drill and adjacent the top of the drill.
[0013] This approach will also accommodate both right-handed and left-handed use of the inventive drill by a single individual, something which particular jobs may require.
[0014] Still further efficiency can be provided by the provision of switches associated with each of the lights, so that illumination may be tailored to a particular user's style or a particular job's requirements.
[0015] In accordance with the invention, a drill comprises a drill housing with a handle portion and a driver portion. An electrical drill motor is located in the driver portion. The drill motor has an output shaft for coupling output rotary power. An electrical switch controls the operation of the drill motor. The electrical switch is located on the handle portion of the drill housing. A chuck is coupled to the output shaft of the drill motor.
[0016] A light is positioned to principally illuminate those areas of the workpiece which are likely to be visible to the user of the tool.
[0017] The inventive drill also comprises charge state measuring circuitry having a plurality of output terminals. Actuation of the output terminals or a combination of output terminals each corresponds to a particular state of charge. A red indicator light is coupled to one of the output terminals. One of the output terminals indicates a relatively poor state of charge. A green indicator light is coupled to an other one of the output terminals. The other one of the output terminals indicates a relatively good state of charge. A charge test switch actuates the charge state measuring circuitry.
[0018] The charge state measuring circuitry further comprises an output terminal for driving a yellow light. The charge state measuring circuitry actuates the yellow light to indicate a condition which is neither good nor poor. It also actuates the green light and the yellow light simultaneously to indicate a battery charge condition that is better than that indicated by the yellow light but not as good as that indicated by the green light. The measuring circuitry also actuates the red light and the yellow light simultaneously to indicate a battery charge condition that is worse than that indicated by the yellow light but not as bad as that indicated by the red light. The indicator lights may be located on the left side of the handle portion of the drill housing.
[0019] In accordance with the invention, a green directional indicator and a red directional indicator are included to indicate movement of the drill chuck, with the green indicator indicating movement in a clockwise direction and the red indicator indicating movement in a counterclockwise direction.
[0020] The indicator lights may be located on the top of the driver portion of the drill housing. The red and green indicator lights and the charge test switch may be located adjacent the left side of the drill in the case of a drill primarily intended for a right-handed user.
[0021] A first workpiece illuminating light may be provided on the left-hand side of the drill, and a second workpiece illuminating light may be positioned on the top of driver portion of the drill. A light may be positioned to principally illuminate those areas of the workpiece which are likely to be visible to the user of the tool and may comprise a plurality of light sources positioned circumferentially about a forward end of the driver portion. A workpiece illumination light may be positioned on the top of driver portion of the drill to illuminate more visible portions of the workpiece. Another workpiece illumination light may be positioned adjacent the bottom of driver portion of the drill housing to illuminate remaining more visible portions of the workpiece not likely to be covered by the hand of the user and the handle portion of the drill housing.
BRIEF DESCRIPTION THE DRAWINGS
[0022] The operation of the invention will become apparent from the following description taken in conjunction with the drawings, in which:
[0023] FIG. 1 illustrates a general implementation of a drill in accordance with the present invention;
[0024] FIG. 2 is a front view of the drill of FIG. 1 ;
[0025] FIG. 3 is a left side view of the drill of FIG. 1 ;
[0026] FIG. 4 is a front view showing another illumination design;
[0027] FIG. 5 illustrates an alternative embodiment of the drill of the present invention;
[0028] FIG. 6 illustrates another alternative inventive illumination structure;
[0029] FIG. 7 illustrates an indicator useful in the present invention; and
[0030] FIG. 8 illustrates a detail of the illumination of FIG. 7 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] As illustrated in FIG. 1 , an electric drill 10 including an illumination system particularly configured in a manner which maximizes the efficiency of the use of electricity for illumination in an electrical power driving device such as a drill and constructed in accordance with the present invention is illustrated.
[0032] Drill 10 includes a handle portion 12 and a driver portion 14 . Driver portion 14 comprises a neck 16 . A chuck 18 , of conventional design, is mounted on a spindle 20 . In accordance with the preferred embodiment, it is contemplated that chuck 18 may be any conventional hex socket chuck, as a wide variety of tool bits having mountings suitable for such chucks are readily available on the market.
[0033] Alternatively, a multi-fingered chuck, for example one of the type using a serrated sleeve may be employed. Alternatively, a multi-fingered chuck employing a conical gear pin key (such as that sold by Jacobs Manufacturing) may also be advantageously employed in accordance with the present invention. Spindle 20 is coupled to a motor, not illustrated, but of conventional design, housed within driver portion 14 . In accordance with the invention, drill 10 is capable of both forward and reverse movement. The same is achieved using conventional circuitry.
[0034] Driving direction is selected by an on/off switch 22 . Switch 22 includes a lever operator 24 mounted for rotation about a pivot bar 26 , illustrated in hidden lines in FIG. 1 . Lever operator 24 is mounted with a conventional spring mechanism which biases lever operator 24 in the position illustrated in FIG. 1 .
[0035] Upon the application of pressure to the upper portion 28 of lever operator 24 , in the direction of arrow 30 , spindle 20 is caused rotate in the clockwise direction, thus causing drill bit 32 to rotate clockwise and drill into a workpiece, for example creating a hole or driving a screw into a workpiece. It is noted that a drill bit 32 is shown for purposes of illustration, but that drill 10 may be used to rotate a wide variety of tools, such as bits with conventional slot and Philips screwdriver tips of all types and sizes, hex wrench bits and specialized tools such as star drivers and four sided drivers.
[0036] Upon the application of pressure to the lower portion 34 of lever operator 24 , in the direction of arrow 36 , spindle 20 is caused rotate in the counter-clockwise direction, thus causing drill 32 to rotate counter-clockwise and withdrawn from the workpiece, leaving behind the hole. In accordance with a preferred embodiment of the invention, a three position switch 38 with a slider selection member 40 changes the state of inventive drill 10 from a first position illustrated in dashed lines, where it is operable and lights illuminate the workpiece, to, when slider member 40 is in the position illustrated at 40 a, an “on” position where the drill will operate but no illumination is provided, when slider member 40 is illustrated in solid lines.
[0037] Slider member 40 may also be put in the locked position shown in dashed lines as indicated by reference numeral 40 b, in which position neither tool operation nor illumination is provided. Such locking and turning on of lights using a slider switch is conventional and three position switch 38 may be of any conventional design.
[0038] Light 44 is oriented in a direction which causes it to illuminate the workpiece as illustrated in FIG. 1 . In accordance with a preferred embodiment, a marking showing the position for the application of force by the finger of the user to achieve a forward or clockwise drilling operation takes the form indicated by forward alphanumeric indicator 46 . Likewise, rearward or counterclockwise motion may be achieved by squeezing switch 22 in the direction indicated by arrow 36 adjacent rearward alphanumeric indicator 48 . For ease of operation a second forward alphanumeric indicator 50 and a second rearward alphanumeric indicator 52 are provided on the opposite side of the drill as illustrated in FIG. 3 .
[0039] The inventive drill 10 further comprises a battery testing switch 54 . Adjacent battery testing switch 54 is a red light 56 which is positioned beside a yellow light 58 , which in turn, is positioned beside a green light 60 . Lights 56 - 60 are connected to a battery testing circuit, with actuation of a red light indicating a very weak battery, and a weak battery indicated by simultaneous lighting of red light 56 and yellow light 58 . Actuation of only yellow light 58 indicates a weakening battery. Actuation of yellow light 58 and green light 60 indicates a relatively strong battery condition. Finally, actuation of green light 60 indicates a battery which is substantially fully charged. These various actuation combinations may be obtained from a conventional voltage measuring circuit and a suitable gating arrangement driving the lights as are within the design capability of one of ordinary skill in the art.
[0040] The presence of state of charge indication circuitry is as indicated by an indicia 61 of conventional configuration. The position of switch 54 is particularly advantageous, being on the left side of the drill handle 12 because a right handed user is relatively unlikely to accidentally actuate switch 54 . The result is a very accessible state of charge indicator. On the other hand, because the indicator lights 56 - 60 are also visible when the drill is held in the right hand, access is particularly easy. Likewise, switch 54 is easily accessible to the left hand when the drill is held in the normal position by the right-hand, which also promotes ease-of-use.
[0041] In accordance with a preferred embodiment of the invention, lights, for example light emitting diodes, are provided to illuminate the workpiece. Generally, that portion of the workpiece, which lies adjacent to the handle, is not easily visible or commonly visible to the user. Accordingly, the provision of lights in such a position, for example as illustrated by light 62 in FIG. 4 may not be the most advantageous arrangement, because it illuminates portions of the workpiece which are not visible. Accordingly, in accordance with the invention, as illustrated in FIGS. 2 and 3 , lights 64 , 66 and 68 are provided in positions which are more efficient. More particularly, light 64 on the left-hand side of the drill illuminates the most visible portions of the workpiece.
[0042] Likewise, light 66 positioned on the top of driver portion 14 of drill 10 illuminates relatively visible portions of the workpiece. Finally, light 68 illuminates the remaining portion of the workpiece not likely to be covered by the hand of the user and handle portion 12 of drill 10 .
[0043] An alternative embodiment of the inventive drill 110 is illustrated in FIG. 5 . Drill 110 is similar to drill 10 except for the inclusion of a light illumination package comprising lights 164 and 166 . This arrangement takes care of the two most effective lighting areas being at the top and the left-hand side of the drill in the case of a right-handed user. This configuration may be reversed for left-handed users with the reconfiguration of light 164 to a position on the right side of the drill (as opposed to the left side of the drill).
[0044] In accordance with the invention, as illustrated in FIG. 6 , it is contemplated that a drill 210 may comprise three lights 264 , 266 and 268 . This results in added illumination, as well as some additional lighting on the right side of the drill.
[0045] As an alternative to the state of charge indicator illustrated in the embodiment of FIGS. 1-3 , the inventive drill may have an indicator arrangement as illustrated in FIG. 7 . In accordance with this embodiment, the inventive drill includes an indicator 470 located on the top of the drill 410 .
[0046] Referring to FIGS. 7 and 8 , inventive drill 310 further comprises a battery testing switch 354 located on the top of the housing. Adjacent battery testing switch 354 is a window 355 behind which is mounted a red light 356 . In accordance with the present invention, window 355 is made of a transparent plastic which allows light from light 356 to exit. In accordance with the preferred embodiment, light 356 as well as the other lights included in the various embodiments of the invention are light emitting diodes, although other light sources, principle, may be used. Window 355 and light 356 are positioned circumferentially beside the second window 357 , behind which is positioned a yellow light 358 . A third window 359 is positioned circumferentially beside window 357 . A green light 360 is positioned behind window 359 .
[0047] Lights 356 - 360 are connected to a battery testing circuit, with actuation of a red light indicating a very weak battery. A weak battery is indicated by simultaneous lighting of the red light 356 and yellow light 358 . Actuation of only yellow light 358 indicates a weakening battery. Actuation of yellow light 358 and green light 360 , simultaneously, indicates a relatively strong battery condition. Finally, actuation of green light 360 indicates a battery which is substantially fully charged. These various actuation combinations may be obtained from a conventional voltage measuring circuit and a suitable gating arrangement driving the lights. The presence of state of charge indication circuitry is indicated by an indicia 361 of conventional configuration.
[0048] The position of switch 354 is particularly advantageous, being on the top of the drill driver portion 314 because it is not likely to be accidentally actuated. The result is a very accessible state of charge indicator. On the other hand, because the indicator lights 356 - 360 are also visible when the drill is held in either hand, access is particularly easy. This promotes ease-of-use.
[0049] Indicator 370 also includes green indicator lights 372 which is actuated when the inventive drill 310 is turned on in the forward or clockwise direction. Similarly, red lights 374 is actuated when drill 310 is turned on in the reverse or counterclockwise direction.
[0050] In accordance with a preferred embodiment of the invention, indicator lights 372 and 356 are different colors, in order to avoid potential misinterpretation of the signal associated with light actuation. Likewise, indicator lights 374 and 360 are different colors, also in order to avoid potential misinterpretation of the signal associated with light actuation. | In accordance with the invention, a drill comprises a drill housing with a handle portion and a driver portion and incorporating a circumferential workpiece illumination system. An electrical drill motor is located in the driver portion. The drill motor has an output shaft for coupling output rotary power. An electrical switch controls the operation of the drill motor. The electrical switch it is located on the handle portion of the drill housing. A chuck is coupled to the output shaft of the drill motor. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional Patent Application Ser. No. 61/062,380, filed Jan. 25, 2008.
FIELD OF THE INVENTION
[0002] This invention relates to compound bows, and more specifically, it relates to a two-track system for bow strings and power cables of the compound bow.
BACKGROUND OF THE INVENTION
[0003] Cams have been used on compound bows for some time. Compound bows have opposing limbs extending from a handle portion which house the cam assemblies. Typically, the cam assemblies are rotatably mounted on an axel which is then mounted on a limbs of bow. The compound bows have a bow string attached to the cam which sits in a track and also, generally, two power cables that each sit in a track on a separate component on the cam, and either anchored to the cam or a limb/axel. When a bowstring is pulled to full draw position, the cam is rotated and the power cables are “taken up” on their respective ends to increase energy stored in the bow for later transfer, with the opposing ends “let out” to provide some give in the power cable.
[0004] Cam assemblies are designed to yield efficient energy transfer from the bow to the arrow. Some assemblies seek to achieve a decrease in draw force closer to full draw and increase energy stored by the bow at full draw for a given amount of rotation of the cam assembly.
[0005] There exists a number of U.S. patents directed to compound bows, including U.S. Pat. No. 7,305,979 issued to Craig Yehle on Dec. 11, 2007. The Yehle patent discloses a cam assembly having a journal for letting out a draw cable causing the cam to rotate and two other journals for take-up mechanism and a let-out mechanism for the two power cables. The Yehle patent requires that the power cables and draw string each sit in a different components and tracks for the take up and let out mechanism to work and to have the efficiencies described therein.
[0006] Therefore, a compound bow having a mechanism with fewer tracks is desired because of the advantage in assembly in manufacturing and to increase efficiency in the transfer of energy to propel bows.
[0007] Further, an adjustable or modular take-up/let-out mechanism is desired to account for different size draw lengths or other specifications required by the user.
SUMMARY OF THE INVENTION
[0008] The invention comprises, in one form thereof, a cam assembly comprising bowstring cam component having a track for receiving a bowstring; and a power cable cam component having a take up portion and a let out portion, wherein the take up and let out portion have a track for receiving a power cable.
[0009] More particularly, the invention includes a compound bow comprising a handle portion; a limb portion; at least two cam assemblies, each comprising a bowstring cam component having a track for receiving a bowstring; and a power cable cam component having a take up portion and a let out portion, wherein the take up and let out portion have a track for receiving a power cable, a draw stop pin, a take up terminating post, and a let out terminating post; an axel; at least two power cables; and a bowstring.
[0010] The cam assembly has a two track system wherein the power cables utilize a track or opposing tracks made on the power cable component of the cam assembly. Another track is formed on the bowstring component of the cam assembly in which the bowstring lies.
[0011] An advantage of the present invention is that the device has high efficiency in transfering energy stored in the limbs during the draw cycle to the arrow or other projectile of the device.
[0012] A further advantage of the present invention is that it requires less component parts for cam assembly which is highly desireable in the art.
[0013] An even further advantage of the present invention is that the cam assembly allows for a modular format which allows the user to change minor components to change parameters of the device (e.g. draw length) without having to change the entire cam assembly or bow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention is disclosed with reference to the accompanying drawings, wherein:
[0015] FIG. 1 is a side view of a dual cam compound bow embodying the present invention;
[0016] FIG. 2 is a side view of the top cam assembly in a first embodiment of the present invention.
[0017] FIG. 3 is a rearview of the top cam assembly in a first embodiment of the present invention.
[0018] FIG. 4 is a side view of the bottom cam assembly in a first embodiment of the present invention.
[0019] FIG. 5 is a rearview of the bottom cam assembly in a first embodiment of the present invention.
[0020] FIG. 6 and 7 show the modular form of the let out portion 64 a,b with the draw stop pin 90 a,b attached thereto.
[0021] FIG. 8 is a side view of the top cam assembly in a second embodiment of the present invention.
[0022] FIG. 9 is a side view of the bottom cam assembly in a second embodiment of the present invention.
[0023] FIG. 10 is a side view of the top cam assembly in a third embodiment of the present invention.
[0024] FIG. 11 is a side view of the bottom cam assembly in a third embodiment of the present invention.
[0025] FIG. 12 is a rearview of the top cam assembly in a fourth embodiment of the present invention.
[0026] FIG. 13 is a rearview of the bottom cam assembly in a first embodiment of the present invention.
[0027] Corresponding reference characters indicate corresponding parts throughout the several views. The examples set out herein illustrate a few embodiments of the invention but should not be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION
[0028] FIG. 1 shows a dual cam compound bow 10 of the present invention. The bow 10 has a frame, which includes bow limbs 12 a,b extending from handle 14 . Extending from the handle is cable guard 16 and a cable slide 18 through which the power cables 50 and 52 are placed. The bowstring 70 and power cables 50 , 52 are attached to the bow 10 at the cam assemblies 30 a,b , which further is placed on the limbs via axel 36 a,b. The cams 30 a,b are shown in greater detail in the following figures.
[0029] The cams 30 a,b have bowstring assemblies 40 a,b , each having a single track for the bowstring 70 with each end of the bowstring 70 being attached to the cams 30 a,b at a terminating post (not shown). Further, the each of the cams 30 a,b have terminating posts 80 , 82 for each of the ends of the respective power cables 50 , 52 , and which will be described in more detail herein. Further, each cam assembly 30 a,b has a power cable assembly 60 a,b having either a single track or groove around perimeter of the assembly 60 a,b for receiving or retaining the power cables. Alternatively, the power cable assembly 60 a,b can have the tracks or grooves on the portions of the assembly receiving the cable instead of a unitary track around the perimeter. The power cable assembly 60 a,b has a take up portion 62 a,b and a let out portion 64 a,b for managing the take up and let out of the power cables through a single track.
[0030] FIG. 2 shows a side view of the top cam assembly 30 a . FIG. 2 shows one embodiment of the cam 30 a in non-circular shape. The bowstring 70 is in line with the track in the bowstring assembly 40 a and attached with a terminating post (not shown). The power cable assembly 60 a has a take up portion 62 a and a let out portion 64 a , and can either be a unitary piece or be modular. For instance as shown in FIG. 2 , the power cable assembly 60 a has a modular unit for the let out portion 64 a , which allows manufacturers to make a single cam assembly with one small piece that can account for varying sizes and preferences by the user. Specifically, this versatility is important because each hunter or archer has different specifications (e.g. draw length) which can be accounted for by having a modular portion to the cam assembly 30 a , and in this case is the let out portion 64 a . The power cable 52 , in FIG. 2 , is attached to terminating post 82 a and wraps around the let out portion 64 a and therefore feeds power cable 52 out when the bow is in full draw. On the opposing side of power cable assembly 60 a is power cable 50 , which sits on the take up portion 62 a of the assembly 60 a . Power cable 50 is attached at terminating post 80 a , and is taken up when the bow is in full draw by the take up portion 62 a . The power cable assembly 60 a is attached to the bowstring assembly 30 a by a fastening mechanism, but it will be well recognized the power cable assembly 60 a can be attached to the bowstring assembly 40 a by any means or, if desired, manufactured as a single piece with the bowstring assembly 40 a to make-up top cam assembly 30 a . As shown, the power cable assembly 60 a is attached to the bowstring assembly 40 a by a fastener 78 a . The cam assembly 30 a is attached to the limb 12 a by axel 36 a . Last the take power cable assembly 60 a , either in a unitary form or modular form, may optionally have draw stop pin 90 a attached to stop the draw cycle of the bow. The draw stop pin 90 a , however, does not have to be attached to the power cable assembly 60 a in order to function on the cam assembly 30 a.
[0031] FIG. 3 shows the rearview of the top cam assembly. As seen from this perspective, the cam assembly 30 a has one track on the bowstring assembly 40 a for the bowstring 70 and a second track for the power cables 52 and 50 (not shown) on same track but on opposing sides of the power cable assembly 60 a . In FIG. 3 , the let out portion 64 a is visible with power cable 52 sitting in the track or groove. Axel 36 a is inserted through the limb 12 a and then the cam assembly 30 a and then the other end of the limb 12 a.
[0032] FIG. 4 shows a side view of the bottom cam assembly 30 b . FIG. 4 shows the bottom cam 30 b in non-circular shape as well. The bowstring 70 is in bowstring assembly 40 b and attached with a terminating post (not shown). The power cable assembly 60 b has a take up portion 62 b and a let out portion 64 b , which can either be a unitary piece or as shown can have a modular unit. In FIG. 4 , there is a modular assembly shown where the let up portion 64 b can be changed in size and shape according to the user's specifications. The power cable 52 , in FIG. 4 , is attached to terminating post 80 b and wraps around the take up portion 62 b and therefore is taken up when the bow is in full draw. On the opposing side of power cable assembly 60 b is power cable 50 , which attaches to terminating post 82 b and wraps around the let out portion 64 b , and is let out when the bow is in full draw position. The power cam assembly 60 b is attached to the bowstring assembly 30 b by a fastening mechanism, the two assemblies can be attached by any means or if desired manufactured as a single piece. As shown, the power cable assembly 60 b is attached to the bowstring assembly 40 b by a fastener 78 b . The cam assembly 30 b is attached to the limb 12 b by axel 36 b . Last the power cable assembly 60 b , either in a unitary or modular form, may optionally have draw stop pin 90 b attached to stop the draw cycle of the bow.
[0033] FIG. 5 shows the rearview of the bottom cam assembly 30 b . As seen from this perspective, the cam assembly 30 b has a bowstring assembly 40 b for the bowstring 70 , and a power cable assembly 60 b for both power cables 50 , 52 . In FIG. 5 , power cable 50 is visible because it is sitting on the let out portion 64 b of the power cable assembly 60 b . Axel 36 b allows bottom cam assembly 30 b to rotate when the drawstring is pulled, and holds bottom cam assembly 30 b in limb 12 b.
[0034] FIG. 6 and 7 show the modular form of the let out portion 64 a,b and draw stop pin 90 a,b for the cam assemblies 30 a,b . The let out portion 64 a,b and draw stop pins 90 a,b can be attached in any number of ways or can be further manufactured as a unitary piece. Further, as described above, let out portion 64 a,b can be manufactured as a single part of power cable assembly 60 a,b . Therefore, though the modular form is more desirable to personalize the parameters of the device size (e.g. draw length), the cam assembly could be manufactured as a single unit or in varying degrees of pieces.
[0035] FIG. 8 and 9 show a side view of a second embodiment of the present invention 100 a,b. FIG. 8 shows the top cam assembly 100 a is in a circular shape. In particular, the power cable assembly 120 a is shown as being in a unitary form, having the take up portion 122 a and let out portion 124 a . The draw stop pin 90 a is not attached to the power cable assembly 120 a , though if preferred the assembly 120 a could be attached to the pin 90 a . Further the bowstring assembly 110 a is also in a circular or disc shape with power cable assembly 120 a attached thereto. FIG. 9 exemplifies the bottom cam assembly 100 b for the second embodiment, which is in a circular or disc shape. Generally the other components of the cam assemblies 100 a,b are similar to those shown in the first embodiment.
[0036] FIGS. 10 and 11 show a third embodiment of the present invention, wherein the cam assembly 200 a,b have a circular portion for the bowstring track 110 a,b and a non-circular power cable assembly 60 a,b . It will be understood that other embodiments could include a non-circular portion for the bowstring assembly and a circular power cable assembly and, again, can be either modular or unitary form. Further other geometrical shapes, such as ovular, may be used in varying forms for either the bowstring or power cable assembly.
[0037] Still another embodiment could include a three track system, as shown in the rearview perspectives of FIG. 12 and 13 . The three track system would be used where there are four power cables. This type of embodiment would include two power cable assemblies as described above, both of which would be attached to the bowstring assembly.
[0038] In use, using the first embodiments as an exemplar and in reference to FIGS. 1-3 , the bowstring 70 is pulled rearward toward the hunter or archer. The tension by the bowstring forces the cam assemblies 30 a,b to rotate rearward. Focusing on FIG. 1 , the power cable assembly 60 a on top cam assembly 30 a is moved upward as the entire cam 30 a is moved rearward. The terminating post 80 , with power cable 50 attached, moves upward, and therefore causes take up of power cable 50 . On the bottom cam assembly 30 b the cam 30 b is also moved rearwardly. The positioning of the power cable assembly 60 and power cable 50 causes power cable 50 to be let out on the bottom cam assembly 30 a . The same is true in the opposite manner for power cable 52 (i.e. power cable 52 is taken up) on the cam assemblies 30 a,b . Accordingly energy is stored in the limbs of the device and transferred to the arrow or other projectile placed in the compound bow in a highly efficient manner with little shock to the user.
[0039] Though the compound bow embodying the invention may have differing specifications, the bow may have a brace height of about eight (8) inches and axel-to-axel length of about thirty-two and half (32½) inches. The draw length can range from twenty-seven (27) to thirty (30) inches and a draw weight between sixty (60) to eighty (80) inches.
[0040] It should be particularly noted that dual track cam disclosed in this invention has a highly efficient and powerful performance. With respect to speed, the following performance results were noted in a twenty-nine (29″) inch draw cycle, sixty pound (60 lbs.) draw weight compound bow, in testing completed by Archery Evolution:
[0000]
Arrow (Grains)
300
360
420
540
Speed (ft./sec.)
307.3
283.5
264.2
235.4
Kinetic Energy (ft.lbs.)
62.9
64.2
65.1
66.4
Momentum
13.2
14.6
15.9
18.2
Dynamic Efficiency
83.7%
85.5%
86.7%
88.5%
Noise Output (dBA)
88.7
84.1
85.5
87.1
Total Vibration (G)
222.8
234.4
228.7
188.6
[0041] While the invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope of the invention.
[0042] Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims. | The present invention comprises a two-track cam assembly wherein the cam assembly has a bowstring component for housing the bowstring and a power cable component that allows for the take up and let out of the power cable on opposing ends of the power cable component, effectively creating a two-track cam assembly. The efficiency rating of the device achieves 95.8%. The cam assembly can come in a unitary or modular form and further each component (i.e. The bowstring or power cable component) can be in a circular or non-circular form. |
FIELD OF THE INVENTION
[0001] The present invention relates to ventilators, ventilating devices, apparatuses, systems and/or installations and, more particularly, to ventilators, ventilating devices, apparatuses, systems and installations including a thermal exchanger and an exchangeable air filter. This invention also relates to air conditioners having a built-in thermal exchanger together with an exchangeable air filter disposed at the upstream end of the fresh air inlet to said thermal exchanger.
BACKGROUND OF THE INVENTION
[0002] In this specification, the term “air-conditioners” generally and collectively means air heating, cooling, drying, moistening and other air conditioning devices, apparatuses, systems and installations for succinctness unless the context requires otherwise. Likewise, the term “ventilators” generally and collectively means ventilating or air-circulating means, devices, systems or installations for succinctness, unless the context otherwise requires. Throughout this specification, the term ventilators, ventilating apparatus and air-conditioners may be considered equivalent to the extent appropriate.
[0003] Air-conditioners are widely used to provide comfortable indoor conditions for occupants of residential, commercial or public buildings, premises or other enclosed spaces such as offices, schools, cinemas, theatres, halls, and other similar places. However, while many air-conditioners are provided with means to remove stale indoor and introduce fresh out-door air, their performance is not entirely satisfactory. In fact, there have been reports that the indoor carbon-dioxide concentration in many air-conditioned schools exceeds the generally acceptable level of 800 ppm by as much as 35%.
[0004] To supplement the performance of air-conditioners, ventilators may be used with or built-in to air-conditioners so that indoor air, which may contain a high concentration harmful gases, can be constantly and regularly replaced with air supply which has a higher oxygen content and a lower harmful gas content. Typical harmful gases found in enclosed buildings, especially crowded buildings, include carbon-dioxide, carbon-monoxide, unpleasant odors, irritants and harmfful gases such as formaldehyde in the building materials and the radioactive radon gas released from granite.
[0005] On the other hand, although out-door air generally has a higher oxygen content, it is not without pollutants and air-pollution is especially bad in heavily built-up urban or city areas. Typical pollutants found in out-door air include particulate pollutants such as dusts, ashes, smoke particles, particles from incomplete combustion of diesel fuel, pollens, odors, acid or other chemical gases, and bacterial organisms.
[0006] In order to block, or at least minimise, the entrance of harmful substances into an enclosed indoor space to provide a healthier indoor environment, ventilators or air-conditioners are usually provided with air filters at the “fresh-air” intake ports. The air filters may be simple mesh filters or more sophisticated filters such as activated carbon filters, polymeric foam filters, glass fiber filters and biostat filters such as those containing potassium permanganate are useful alternatives or additions. In some applications, high-efficiency particulate air (HEPA) filters which are known to be effective to remove up to 99.7% of air-borne particles of the size of 0.3 microns or larger, can be used. Some air filters for use in air-ventilators may include one or more types of filtering materials and designs in order to optimally removed different types of harmful substances from the supply air.
[0007] Since the conditioned indoor air to be exhausted usually or, as a norm, contains reusable thermal energy, it is desirable that such ventilators are provided with thermal exchangers so that reusable thermal energy can be exchanged between the in-coming and the out-going air streams. With this energy recycling process, an additional supply of out-door air into an enclosed indoor space can be provided with less energy costs or wasted energy.
[0008] Examples of ventilators with thermal exchangers are described in the following U.S. Patents: U.S. Pat. No. 5,238,052, U.S. Pat. No. 4,874,042, U.S. Pat. No. 4,377,400. In those examples, thermal exchangers are utilized to recover thermal energy from the out-going air stream to reduce wasted thermal energy discharged from the exhaust air. This recouperation of energy is beneficial for the protection of the environment, as well as imposing a lesser load or demand on the air-conditioners and, at the same time, reducing the operating and running costs of air-conditioners. Such benefits are achievable because it is known that thermal exchange between a cold air stream and a hot air stream will reduce the total energy requirement for conditioning the in-coming air stream. Thus, for an air-cooling system, the in-coming air stream is cooled by the out-going or exhaust chilled air before the exhaust air leaves the air-conditioner. Similarly, for an air-heating system, the out-going warm air is used to warm up the in-coming out-door air before it enters a building.
[0009] It is therefore desirable to provide ventilators with high efficiency air filters which operate with high thermal efficiency and low running costs so that the environment can be protected, wasted heat as well as energy costs can be reduced. As space is usually precious in city areas, it is also desirable that the improved ventilators are simple and compact. Preferably, important parts or components, such as the thermal exchanger unit, of the air-ventilators are of modular design for easy maintenance. In addition, while the air-ventilator can be used as a stand-alone unit, it is desirable that the improved air-ventilators can be incorporated or used in or with air-conditioners.
[0010] In light of the afore-mentioned requirements for contemporary air-conditioners, it is highly beneficial and desirable that air-conditioners incorporating thermal exchangers as well as highly efficient air filters with high durability and reliability are provided. However, it has been observed that the performance of conventional air-conditioners of this description degrades after an extended period of use. Hence, it is highly desirable that air-conditioners or ventilators with highly efficient thermal exchangers and air filters which can provide a stable performance over a period of extend use can be provided. At least, such ventilators should have a design which can be easily or conveniently maintained for consistent performance.
OBJECT OF THE INVENTION
[0011] Accordingly, it is an object of the present invention to provide improved ventilators with thermal exchangers and highly efficient air filters, preferably, such ventilators are simple, compact and reliable. It is another object of the present invention to provide improved ventilators with thermal exchangers which overcome, or at least alleviate, the shortcomings associated with such known ventilators. Preferably, the ventilators are of modular design for easy maintenance. As a minimum, it is an object of the present invention to provide the public with a choice of ventilators or air-conditioners incorporating thermal exchangers and filters which are compact, durable and reliable.
SUMMARY OF THE INVENTION
[0012] According to the present invention, there is provided a ventilating apparatus including a main housing, a thermal exchanger, a first and a second air-moving devices and a removable air-filter,
[0013] said main housing includes a front housing, a rear housing, a first and a second air compartments, and a filter compartment,
[0014] said thermal exchanger and said air-moving devices are disposed within said main housing and between said front and rear housings,
[0015] said thermal exchanger includes an intake section and an exhaust section,
[0016] said front housing includes at least an aperture connecting to the downstream end or outlet of said intake section of said thermal exchanger.
[0017] said first and second air-moving devices are respectively for moving air through said intake and exhaust sections of said thermal exchanger,
[0018] said first air compartment connects said intake section of said thermal exchanger, said first air-moving device and said filter compartment such that said filter compartment is disposed upstream of said intake section of said thermal exchanger for removably receiving said air filter,
[0019] said second air compartment connects said exhaust section of said thermal exchanger and said second air-moving device,
[0020] a section of said first air compartment upstream of said intake section of said thermal exchanger, being that section of said first air compartment containing said filter compartment, is adjacent to and accessible or communicable through said front housing.
[0021] According to another aspect of this invention, there is provided a ventilating apparatus for transferring air between a confined space and an external space according to any of the preceding claims, wherein said first aid compartment provides a path for moving air from said external space into said confined space, said second air compartment provides a path for moving air from said external space to said confined space, wherein, when installed for operation, said main housing bridges between said external space and said confined space such that said front housing and said rear housing are present respectively in said confined space and said external space, said aperture on said front housing downstream of such intake section provides an inlet interface for air to move from said external space to said confined space.
[0022] According to a further aspect of this invention, there is provided a ventilating apparatus for transferring air between a first space and an second space including a main housing, a thermal exchanger, a first and a second air-moving devices and a removable air-filter,
[0023] said main housing includes a front housing, a rear housing, a first and a second air compartments, and a filter compartment,
[0024] said thermal exchanger and said air-moving devices are disposed within said main housing and between said front and rear housings,
[0025] said thermal exchanger includes an intake section and an exhaust section,
[0026] said front housing includes apertures connecting to the downstream end or outlet of said intake section of said thermal exchanger.
[0027] said first and second air-moving devices are respectively for moving air through said intake and exhaust sections of said thermal exchanger,
[0028] said first air compartment connects said intake section of said thermal exchanger, said first air-moving device and said filter compartment such that said filter compartment is disposed upstream of said intake section of said thermnal exchanger for removably receiving said air filter,
[0029] said second air compartment connects said exhaust section of said thermnal exchanger and said second air-moving device.
[0030] at least a section of said first air compartment upstream of said intake section of said thermnal exchanger, being that section of said first air compartment containing said filter compartment, is adjacent to and accessible through said front housing, and
[0031] said front housing includes an aperture through which said air filter can be inserted into or removed from said filter compartment, wherein,
[0032] when installed for operation, said main housing separates said first and said second spaces so that said front housing and said rear housing are respectively present in said first and said second spaces and apertures on said front housing downstream of such intake section of said thermal exchanger provide an inlet interface for air to move from said first space to said second space.
[0033] Preferably, said front housing includes an aperture through which said air filter can be inserted into or removed from said filter compartment.
[0034] Preferably, said filter compartment generally extends between said front and rear housings.
[0035] In one specific embodiment, said main housing includes a longer side extending in a general lengthwise direction and including said front and rear housings and a shorter side generally extending from said front housing towards said rear housing, at least an aperture providing an upstream path to said filter compartment is provided on said shorter side. Preferably, said filtering plane of said filter generally forms an angle with said front housing. Preferable that angle being about 90°. Furthermore, said first housing may include at least an aperture connecting to the upstream end of said exhaust section of said thermal exchanger. Preferably, said front housing also includes a detachable member on which said apertures for connecting to said thermal exchanger and said filter compartment are formed.
[0036] In one example, said first air-moving device is disposed intermediate between said air-filter and the upstream end of said intake section of said thermal exchanger.
[0037] For example, said first air-moving device may include a rotary fan having an axis which is generally perpendicular to said air-filter.
[0038] Preferably, said air-filter includes a combination of activated carbon and HEPA filters.
[0039] Preferably, both said first and second air-moving devices are disposed upstream of said intake and exhaust sections of said thermal exchanger.
[0040] For example, said thermal exchanger includes a plurality of stacked metal sheets configured to form a plurality of air-passageways, wherein air-passageways formed on the two sides of said sheet are alternatively connected to said intake and exhaust sections of said thermal exchanger.
[0041] In the preferred embodiment, the combination of said first and second air moving devices are disposed intermediate between said filter compartment and said thermal exchanger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] Preferred embodiments of the present invention will now be explained by way of example and with reference to the accompanying drawings, in which:
[0043] [0043]FIG. 1 is an illustrative diagram showing the top view of a first preferred embodiment of a ventilator of the present invention with the top part of the main housing removed for showing the arrangement of the various example parts and components with arrows indicating the directions of air flow,
[0044] [0044]FIG. 2 illustrates the front exposed view of the ventilator of FIG. 1,
[0045] [0045]FIG. 3 illustrates the ventilator when viewed from the line A-A,
[0046] [0046]FIG. 4 illustrates the ventilator when viewed from the line B-B,
[0047] [0047]FIG. 5 shows the dis-assembled form of the ventilator of FIG. 1,
[0048] [0048]FIG. 6 illustrates a preferred example of a thermal exchanger suitable for present invention made of stacking aluminium foils with arrows illustrating the air-flow paths,
[0049] [0049]FIG. 7 shows a second preferred example of a ventilator having a thermal exchanger.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0050] Referring to FIGS. 1 to 5 , there is illustrated a first preferred embodiment of a ventilator of the present invention. In the Figures, arrows indicating the directions of air flow within the air-ventilator are provided to assist understanding only.
[0051] The ventilator or ventilating generally apparatus ( 1 ) includes a main housing ( 10 ), a thermal exchanger ( 20 ), a first air moving device ( 30 ), a second air moving device ( 40 ) and an air filter ( 50 ).
[0052] The main housing ( 10 ) provides general support and shielding to the major components as well as providing defined air channels for the air moving in and out of a confined space through the ventilator. The main housing ( 10 ) does not need to be of any specific shape or configuration and the example shown in FIG. 5 is merely provided for illustration only. In general, the main housing ( 10 ) can be said to include a front portion ( 11 ), a rear portion ( 12 ), a top portion ( 13 ), a bottom portion ( 14 ) and a filter compartment ( 15 ).
[0053] The bottom portion ( 14 ) generally includes a rigid structure to support the weight of the operating components. The top portion ( 13 ) generally includes a cover and provides weather shielding to the essential parts and components.
[0054] The front portion ( 11 ) provides a main interface between the indoor space ( 87 ) and the outside ( 88 ) as well as gateways for external air to enter and indoor air to leave the indoor ( 87 ) space. These gateways are, for example, formed by way of grated apertures located corresponding to the downstream and upstream ends and respectively of the intake and exhaust sections of the thermal exchanger. For ease of maintenance, the front portion ( 11 ) may include a detachable cover ( 16 ) with grated apertures so that it can be removed for cleaning the accessible parts periodically.
[0055] The rear portion ( 12 ) of the main housing ( 10 ) generally refers to the part of the main housing which is furthest away or opposing the front portion. The rear portion may provide outlet apertures for the downstream end of the exhaust section of the thermal exchanger. In general, the exhaust outlet should be disposed furthest away from the upstream “fresh air” inlet of the intake section for better intake air quality.
[0056] Referring more particularly to FIGS. 1, 2 and 5 , the thermal exchanger ( 20 ), the air-moving devices ( 30 , 40 ), the filter compartment ( 15 ) and the re-moveable filter are all disposed within the main housing ( 10 ) and between the front and rear housings.
[0057] Inside the main housing ( 10 ), there are provided a first ( 62 ) and a second ( 63 ) enclosed compartments or chambers. The first compartment provide a “fresh air” path (illustrated by solid arrows) for outside air to enter the enclosed indoor space through the air-ventilator. The second compartment or air-passageway (illustrated by broken arrows) provides an exit path (“exhaust air path”) for indoor air to leave the enclosed space through the air-ventilator.
[0058] More specifically, the intake section of the thermal exchanger is connected to the first air moving device ( 30 ) (for drawing outside air), the filter compartment ( 15 ), the air-filter ( 50 ) and the fresh (outdoor) air inlet apertures ( 81 ) by the first air compartment ( 62 ). The second air moving device ( 40 ) (for drawing exhaust air), the exhaust section of the thermal exchanger are connected by the second compartment ( 63 ) or air-passageway. To prevent clogging of the thermal exchanger due to adverse substance in the exhaust air, a filter may be inserted at the upstream end of the second compartment ( 63 ) which is conveniently located on the front housing ( 11 ).
[0059] The thermal exchanger ( 20 ) provides means for thermal energy exchange between the in-coming ( 85 ) and the out-going ( 86 ) air streams so that the total energy requirement for conditioning the air streams coming into the indoor space can be reduced.
[0060] The thermal exchanger ( 20 ) generally includes an intake section ( 21 ) for the incoming air ( 85 ) and an exhaust section ( 22 ) for the out-going air ( 86 ). The intake ( 21 ) and exhaust sections ( 22 ) are brought into close proximity for thermal contact and to bring about thermal exchange between the two streams. However, the air streams in both sections remain separated or un-mixed during the thermal exchanging process. The intake section provides transit thermal exchanging paths for external air to enter the indoor or confined conditioned space. Likewise, the exhaust section provides transit paths for air to leave that indoor or confined space.
[0061] Many types of thermal exchangers are known. For example, the plate-type, the corrugated board type, the fin and tube-type and shell and tube-type heat exchangers. Plate-type heat exchangers are generally less complicated and more easily made and are therefore used in the present preferred embodiment for illustration purpose. Of course, other suitable types of heat exchangers can be used with suitable modifications and adaptations.
[0062] In FIG. 6, there is shown a preferred example of a thermal exchanger ( 20 ) which can be used in the present preferred embodiment. The thermal exchanger ( 20 ) unit includes an assembly of parallelly stacked thermal exchanger elements ( 23 ) which are generally thin metallic sheets, plates or foils, such as aluminium sheets or foils. Thin metallic sheets or foils are preferred because their high thermal conductivity offers high thermal transfer rate and their small thickness offers high thermal sensitivity. These characteristics together offer a high thermal efficiency.
[0063] The thermal exchanging sheet elements are formed with a plurality of additional spacers ( 24 ) which are parallelly distributed along the width of the element. The spacers are preferably ribs with a correspond groove on the other side. The ribs ( 24 ) can be pressed to shape, since thin metallic sheets, especially sheets made of aluminium or aluminium alloys, are substantially semi-rigid. The spacers generally provide additional contact surface area for thermal contact within a sub-channel of a given volume to enhance thermal exchanger efficiency. At the same time, spacers also serve as additional flow guides or regulators within the same sub-channel.
[0064] The thermal exchanging sheets are preferably square, rhombic or even rectangular with the two pairs of opposite sides of the sheets oppositely bent so that one pair is bent upwards and the other pair bent downwards.
[0065] The thermal exchanger sheets are stacked so that the downwardly extending edges ( 26 ) of one sheet are aligned with the upwardly extending edges ( 25 ) of the adjacent sheet element.
[0066] By sealing and joining the aligned downwardly and upwardly extending walls of adjacent sheets, a confined sub-channel having an air-inlet and an air-out on the opposite sides of the metallic sheet is formed. The sealed sides then define the lateral boundary of the confined sub-channel. By stacking the metallic sheets in an alternate manner so that the upstanding walls ( 25 ) (or alternatively, the downwardly extending walls) on adjacent thermal exchanging sheet members are substantially orthogonal to each other, alternate sub-channels having substantially orthogonal orientations are formed.
[0067] The orthogonal sub-channels of the thermal exchanger provide alternate passageways for the in-coming ( 85 ) and out-going air streams ( 86 ) so that they can have thermal interaction without mixing. The multi-layer stacking structure enables the main air-stream to be split into a plurality of sub-streams to increase the effective contact area, thereby increasing the total thermal contact area and hence the thermal transfer efficiency.
[0068] Because thin and light metallic sheets are used to assemble the thermal exchanger, the thermal exchanger is generally light and has a simple structure which can be made and replaced at low costs and relatively easily. The entire thermal exchanger unit ( 20 ) is preferably made as a removable module so that it can be removed for regular servicing or replacement to maintain a high thermal exchange efficiency. For example, the thermal exchanger unit can be assembled within a frame or a cage so that the whole unit can be removed or replaced easily.
[0069] In order to cause air streams to move through intake and exhaust sections of the thermal exchanger so that fresh air is supplied into and stale air removed from the indoor space, air-moving devices are provided. In general, rotary vane wheels, centrifugal fans, blowers, propellers are the commonly used air-moving devices although others can also be used.
[0070] In the present preferred embodiment, the air-moving device for the fresh air path (the “first air-moving device”) includes a rotary vane wheel or a centrifugal fan placed in the first air-passageway intermediate between the air-filter and the thermal exchanger.
[0071] The air-moving device for removing indoor air to the outside (the “second air-moving device”) includes a similar rotary vane wheel or centrifugal fan placed between the thermal exchanger and the indoor air intake port.
[0072] As shown in the Figures, centrifugal fans are used as air-moving devices to cause air movement along the two enclosed air-compartments as well as drawing air from the outside through the filter. However, it should be noted that other comparable air-moving devices, for example, propeller, centrifugal fans and rotary vane wheels can also be used.
[0073] In the present embodiment, the first ( 30 ) and the second ( 40 ) air-moving devices are connected to a common electric motor ( 61 ) so that both air-moving devices are driven by the same motor for a simple and compact construction as well as minimising component costs.
[0074] In order to mitigate, prevent or slow down the building up of adverse substances in a thermal exchanger, a filter must be provided before the external air enters the thermal exchanger. To protect the intake section of the thermal exchanger, an air filter ( 50 ) can be placed at an upstream position before fresh air enters the intake section. For example, the air filter may be placed in the first compartment ( 62 ) and at the fresh air-inlet to the first air moving device. Alternatively, or in combination, an air filter may be placed between the first air-moving device ( 30 ) and the thermal exchanger ( 20 ). The same arrangement may be applied to the exhaust section with suitable and appropriate modification.
[0075] To enhance in-coming air quality an example of a preferred air filter includes a multi-layer filter element which comprises a first layer ( 51 ) of mesh or grid filter, a second layer ( 52 ) of an activated carbon filter and a third layer ( 53 ) of HEPA filter. The first filter layer ( 51 ) is for filtering larger particulate pollutants. The second layer ( 52 ) of activated carbon provides means to absorb odors and can also include other chemical absorptive agents or biostats such as potassium permanganate. The third layer ( 53 ) includes a high-efficiency particulate air (HEPA) filter which is known to be able to remove 99.7% of particulate pollutants of the size of 0.3 microns or larger from air. Of course, “absolute” filters or other chemical-absorptive filters can also be used in combination, in addition, or in replacement to the filter elements, especially in addition to the activated carbon.
[0076] To allow easy cleaning, maintenance and replacement of the individual constituting filter elements, it is preferred that the filter is in modular form and includes modular filter elements. A modular design enables filters having different operating life to be cleaned and/or replaced at different time intervals to attain optimal air filtering. Of course, other modular filters including any suitable filtering elements may be used without loss of generality.
[0077] In general, typical ventilators with thermal exchangers are generally wall mounted through a window opening with the front portion inside the confined indoor space and rear portion outside. For aesthetic considerations and for all practical applications, the portion of the ventilator protruding from or overhanging the window opening must be minimal. As a result, fresh air filters for conventional ventilators are always disposed at the rear portion of the main housing in a filter compartment which is usually located outside and therefore not conveniently accessible.
[0078] In such conventional ventilators, the filters are usually disposed so that the filter plane is generally parallel to the front housing which usually includes a detachable cover with apertures for fresh air supply and stale air removal.
[0079] However, since the filters are mounted outdoors it is extremely difficult and inconvenient to access such air filters for maintenance or cleaning, especially where the ventilators are mounted in high-rise buildings. This at least partly explains why ventilators of this type are not yet widely used.
[0080] In order to enable the air filter to be conveniently accessible for maintenance or replacement, there is provided in the present invention an improved configuration. In particular, a filter accessing aperture is provided on the front portion of the main housing or the removable cover. By, for example, arranging an air filter ( 50 ) that its filtering plane is generally perpendicular to the plane of the front portion of the main housing, as contrast to the conventional filter plane which is substantially parallel to the plane of the front cover, a long existing problem for providing a removable filter for such ventilators has been alleviated.
[0081] In the present invention, the ventilator is configured so that that fresh air inlet ( 82 ) is disposed on one side of the top housing ( 13 ). A detachable air filter ( 50 ) is inserted adjacent to the fresh air inlet so that air is filtered before entering the thermal exchanger. To accommodate such an air filter, a filter compartment ( 15 ) is provided within the main housing ( 10 ). It will be noted that, the filter compartment ( 10 ) generally extends between the front portion of the main housing and the rear portion.
[0082] It will be observed that at least a section of the first air compartment ( 62 ) which is upstream of the intake section of the thermal exchanger ( 20 ) is disposed adjacent to or juxtaposes the front housing. That section corresponds to the filter compartment and is provided with an aperture accessible through the front housing ( 11 ) so that a removable filter can be inserted or removed through the front housing.
[0083] In a second preferred embodiment of the present invention as shown in FIG. 6, and with the same set of numeral reference, the ventilator includes an additional air-moving device ( 70 ) which is placed in the first air compartment ( 62 ) or the fresh air-passageway to compensate for possible imbalances which may result from under-pressure as a result of filter clogging ( 50 ). Filter clogging may result in difficulty in drawing outside air into the enclosed space via the air-ventilator. This additional air-moving device may be a centrifugal fan connected to a second electric motor ( 71 ) which provides additional suction to draw air from the outside through the air-filter. The drawn fresh air is then delivered towards the first air-moving device for continual delivery to the thermal exchanger. As this arrangement mitigates the under-pressure problem, performance of the ventilator can be maintained without the need for a high speed or high power suction device to compensate for the increased loading due to a clogged or partly clogged filter. As a result, both the first and the additional air-moving devices can operate within the preferred normal rotational speed range of 800-1,200 rpm and, at the same time, maintain a high thermal efficiency.
[0084] For a more sophisticated air-ventilator, the additional air-moving device can be micro-processor controlled with sensors monitoring the imbalance in order to provide optimal operation of the additional air-moving device in co-ordination with the other air-moving devices.
[0085] While a preferred example of a ventilator with thermal exchanger and a removable filter or filter module has been described in the present embodiment to assist understanding, it would be appreciated that other suitable arrangements or configurations of ventilators can also be utilised to realise the present invention. For example, while the present example has been explained by reference to a main housing having a generally rectangular shape, it would be obvious to persons skilled in the art that different shapes, for example, trapezoidal, polygonal, can be used while achieving substantially the same result.
[0086] More particularly, it is a general characteristic of the present invention that an air-filter disposed upstream of the intake section of a thermal exchanger can be removed from a position near the fresh air outlet of the ventilator. It is a specific characteristic that the main housing has a longer side with a general longitudinal direction and a shorter direction and the plane of the air filter generally forms an angle, preferably about 90°, with the long direction.
[0087] Furthermore, although the present invention has been described by reference to a stand alone air-ventilator, the present invention can also be incorporated in an air-conditioner to improve thermal efficiency. For example, the fresh air can, after thermal exchange, be passed on to the cooling or heating unit for further conditioning.
[0088] While the present invention has been explained with reference to preferred embodiments described above, it would be appreciated by persons skilled in the art that trivial modifications and variations can be made to realise the concept disclosed in the present invention without departing from the scope and spirit of the present invention. | A compact ventilator with high efficiency thermal exchanger and a conveniently exchangeable air filter. The conveniently exchangeable filter enables a ventilator with thermal exchanger to be easily and regularly maintained and serviced, thereby enhancing its practical utility. |
BACKGROUND OF THE INVENTION
The present invention is directed to a chucking apparatus and more particularly for a roll chucking apparatus directed to, for examples, paper rolls and metal rolls.
Paper and metal are often placed on rolls and shipped to a further processing location. In the case of paper rolls, they are often utilized in newspaper apparatus. Metal rolls, such as rolls of steel or non-ferrous alloys such as copper and brass are shipped to factories or other metal working facilities for further processing.
To move the rolls, it is often necessary to chuck the rolls. During this process, chucking pins are inserted into opposed side openings in the roll. A problem well known in the prior art is that the chucking sometimes results in crushing or otherwise damaging the side edges of the rolled paper or the rolled metal.
To alleviate this problem, computers have been utilized to determine the location of the openings in the paper roll. In response to computer readouts, the chucking pins are moved in a predetermined path. However, it has been found that because of differences in the materials themselves and in the alignment of the rolls, damage still sometimes occurs when the chucking pins engage the paper or metal rather than directly moving into the opposed openings.
The primary object of the roll chucking apparatus, according to the present invention, is to provide an improved chucking apparatus for movement of the chucking pins into the opposed central openings in the side edges of a paper or metal roll, without damaging the rolled material.
STATEMENT OF THE INVENTION
The present invention is directed to a roll chucking apparatus for use with a roll having roll ends, each of the ends defining a central opening. The opposed central openings in the side edges of the roll receive opposed support pins which engage and support the roll. Normally after chucking, the roll is moved from the chucking station to another station such as a machine or press for a further operation. The chucking apparatus includes a platform for supporting the roll. Lift means are provided for vertically adjusting the platform. A load cell means is provided for sensing an increase or decrease in the platform load upon an attempted insertion of the opposed chucking pins into the central side openings of the roll. The platform of the chucking apparatus is moved vertically in response to the reading of the load cell means to vertically align the side openings in the roll with respective ones of the opposed chucking pins.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an end elevational view of a roll chucking apparatus, according to the present invention, shown partially in cross section;
FIG. 2 is a fragmentary sectional view taken along the line 2--2 of FIG. 1;
FIG. 3 is a fragmentary cross sectional view showing a chucking pin inserted in the central opening of a roll;
FIG. 4 is a diagrammatic view of a roll chucking apparatus, according to the present invention, showing the opposed chucking pins engaging the lower portion of the roll core; and
FIG. 5 is a view similar to FIG. 4 showing the opposed chucking pins engaging the upper portion of the roll core.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A roll chucking apparatus, according to the present invention, is generally indicated by the reference number 10 in FIG. 1. The roll chucking apparatus 10 includes a platform 11. A cradle 12 is mounted on the upper surface of the platform 11 and receives a roll, such as a paper roll 13. While a paper roll 13 has been illustrated, the roll chucking apparatus 10 may be utilized in connection with many types of rolls and cylinders. For example, the roll chucking apparatus 10 may also be used with plastic rolls or metallic rolls composed of metals such as steel, brass, copper and other metal alloys.
The paper roll 13 includes a cylindrical core 14 having a continuous layer of paper 15 rolled thereon, which forms the overall paper roll 13.
The roll chucking apparatus 10 includes lift means 17 for vertically adjusting the platform 11. In the present embodiment, the lift means 17 includes an upper frame 18 and a lower frame 19. A concrete floor 21 defines a pit 22 having a bottom surface 23. The lower frame 19 of the lift means 17 is positioned on the bottom surface 23 of the pit 22. A scissors mechanism 25 having opposed pairs of pivotally mounted arms 26 and 27 interconnect the upper frame 18 to the lower frame 19. A prior art scissors mechanism of this type is sold by Southworth. The pairs of pivotally mounted arms 26 and 27 are opened and closed by a pair of cylinders 29. The cylinders 29 are connected to a pivot shaft assembly 30 which extends between the pairs of arms 26 and 27. While the lift means 17, in the present embodiment, has been shown as a scissors mechanism, other types of lift means may be utilized and fall within the scope of the present invention.
A sensing means 32 is positioned adjacent the platform 11. In the present embodiment, the sensing means 32 comprise a plurality of load cells 33 which are connected by conduits 34 to a control box 35. One prior art load cell which can be utilized is the Toledo 951 load cell assembly sold by the Toledo Scale Corporation. In the present embodiment, four load cells 33 are mounted generally adjacent the four corners of the platform 11. The control box 35 includes a micro processor which receives signals from the individual load cells 33 and, if required, transmits a signal to the cylinders 29. The cylinders 29 are extended or retracted to vertically adjust the platform 11 and the paper roll 13. As shown in FIG. 2, an axis 38 of the cradle 12 intersects the center of the core 14 of the paper roll 13 when the paper roll 13 is positioned on the cradle 12. Therefore, the paper roll 13 is correctly aligned horizontally when initially positioned in the cradle 12.
A roll handling apparatus is generally indicated by the reference number 40 in FIGS. 1 and 2. The roll handling apparatus 40 includes movable opposed chucking supports or pins 41. The paper roll 13 includes opposed side edges 43. The side edges 43 include opposed central openings 44 which are defined by the core 14. During the chucking process, the opposed chucking pins 41, after alignment, are inserted into the paper roll openings 44 and the roll handling 40 then normally transfers the paper roll 13 to another work station. The roll handling apparatus 40 is known in the art and is not the subject matter of the present invention. The roll chucking apparatus 10, according to the present invention, can be used with various types of roll handling apparatus other than the roll handling apparatus 40 shown in the drawings.
The roll handling apparatus 40 includes a pair of opposed arms 45 which are interconnected by a shaft 46. Lower ends 47 of the arms 45 mount the opposed chucking pins 41. The pins 41 are reciprocated by cylinders 48. The upper ends 50 of the arms 45 are fixed to a rotatable shaft 51. One end of the rotatable shaft 51 is journaled by a bearing 53 carried by a member 54. The other end of the rotatable shaft 51 extends through a member 55 and is connected to a drive means (not shown) for rotating the shaft.
When it is desired to move the paper roll 13 from the position shown in FIG. 1, the chucking pins 41 are moved into position in the openings 44 defined by the core 14. The platform 11 is lowered and the shaft 51 rotated to swing the paper roll 13 to its next station.
After the paper roll 13 is placed in the cradle 12 and before the chucking pins 41 have been moved inwardly, as noted above, the cradle 12 ensures correct horizontal alignment with the axis 38 (see FIG. 2). Next, the controls of the control box 35 are activated and the cylinders 48 are extended to move the opposed chucking pins 41 inwardly toward the openings 44 defined by the core 14.
FIGS. 4 and 5 are diagrammatic views showing the operation of the roll chucking apparatus 10. FIG. 4 shows the roll chucking apparatus 10 when the roll 13 is spaced vertically upwardly from its correct alignment with the opposed chucking pins 41. FIG. 5 illustrates the situation where the paper roll 13 is misaligned vertically downwardly from the correct alignment with the chucking pins 41.
When the paper roll 13 is misaligned upwardly, as shown in FIG. 4, the chucking pins 41 initially engage the core 14, and as indicated by the arrows, place a downward load on the platform 11. This downward load is immediately sensed by the load cells 33 which transmit a signal to the control box 35 which actuates the pairs of cylinders 29 to move the platform 11 incrementally downwardly until the openings 44 are correctly aligned with the opposed chucking pins 41. In the present embodiment, the four load cells 33 detect an increase or decrease in the pressure or load. The lift means 17 moves the platform 11 in a jogging motion until a neutral pressure is sensed which indicates that the openings 44 defined by the core 14 are correctly aligned for insertion of the opposed chucking pins 41.
Similarly, referring to FIG. 5, if the paper roll 13 is positioned vertically downwardly, the opposed chucking pins 41 initially impose an upward pressure or load. Accordingly, the lift means 17 moves the platform 11 in a jogging motion upwardly until a neutral pressure is sensed indicating that the openings 44 are correctly aligned with for insertion of the chucking pins 41.
Many revisions may be made from the above described embodiment without departing from the scope of the invention and of the following claims. | A roll chucking apparatus is disclosed. The roll defines opposed side openings. The roll chucking apparatus includes a platform from supporting the roll. Lift structures vertically adjust the platform. Sensing structures sense an increase or decrease in the platform load upon the attempted initial insertion of opposed chucking pins into the opposed side openings. The lift structures vertically moves the platform and the roll until correct vertical alignment with the chucking pins occurs. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending International Application No. PCT/SE2004/000275 filed Mar. 1, 2004, which designates the United States of America, and claims priority to Swedish application number 0300686-3 filed Mar. 13, 2003, the contents of which are hereby incorporated by reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to a method and a device for protection of a component or a module, which method and device even would be able to increase the mechanical lifetime of the component or the module. A connectivity from a module to a board is ordinary achieved with pads as via a Land Grid Array (LGA), where an inner area of the module is provided with pads designated for electrical connectivity to corresponding points of connection on the board.
BACKGROUND
[0003] The connectivity from a module to a board is ordinary achieved with pads on the module, which pads when the module is assembled onto the board are provided to be contacted with leads or contact points on the board. The connected pads are difficult to inspect and it is even difficult to determine: or estimate the mechanical lifetime of the module with reference to the pads.
SUMMARY
[0004] To protect a component or a module and to increase the mechanical life time of the component or the module, the outer area of the component or the module is provided with a peripheral outer line of pads forming a sacrifice pad area or pad ring, where individual pad or pads can be sacrificed without destroying the pads, which are provided inside the sacrifice pad area or pad ring on the component or the module. The mechanical lifetime of a module is usually measured by performing rapid temperature change tests of the module, while eventually changes in the configuration of the module and its pads are detected and registered. When using a sacrifice pad area or pad ring on a component or a module and performing rapid temperature change tests, it will be easier to detect damage on the component or the module, because pad or pads of the sacrifice pad area or pad ring will first be destroyed and any deformation or rupture of any pad of the pad area or pad ring can easily be detected and registered as a measure of the quality of the component or the module.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a bottom view of a rectangular component or module with many connections, where the inner pads are uncoloured/white and the outer pads are coloured/grey and constituted to be a sacrifice pad area or pad ring according to the invention.
[0006] FIG. 2 is a bottom view of a circular component or module with many connections, where the inner pads are uncoloured/white and the outer pads are coloured/grey and constituted to be a sacrifice pad area or pad ring according to the invention.
[0007] FIG. 3 is a bottom view of a rectangular component or module with few connections, where the inner few pads are uncoloured/white and the outer pads are coloured/grey and constituted to be a sacrifice pad area according to the invention.
[0008] FIG. 4 is a bottom view of a rectangular component or a module with many connections, where the inner pads are uncoloured/white and the outer pads are coloured/grey and constituted to be a sacrifice pad area or pad ring according to the invention and where at least one pad is removed from the pad area or pad ring to form an asymmetric sacrifice pad area or pad ring.
DETAILED DESCRIPTION
[0009] In FIG. 1 a preferred, rectangular component or module 1 is shown, where 6×9 inner pads 2 are surrounded by an outer pad area or pad ring 3 consisting of four outer lines of pads: 2×10+2×7 pads. The inner pads 2 are provided to be ordinary pads, which function to be connected to a board with corresponding contact points on the board, wherein each pad on the component or the module enables contact with a corresponding contact point on the board for transforming electrical signals between the component or the module and the board. The outer pad area or pad ring 3 constitutes the sacrifice pad area or pad ring and has normally no electrical contact function, but any pad in this pad area or pad ring can in addition be used as test point/points in a production line and can be connected to a detection device, wherein individual pads of the sacrifice pad area or pad ring can be used as internal test points and in most cases their existence has no use for a final user. Pads in the sacrifice pad area or pad ring can be broken as open circuits and this will in most cases not effect the operation of the component or the module.
[0010] In FIG. 2 a circular component or module 4 is shown, where 26 inner pads 5 are surrounded by an outer pad area or pad ring 6 . The inner pads 5 are provided to be ordinary pads, which function to be connected to a board with corresponding contact points on the board, wherein each pad 5 on the component or the module enables contact with a corresponding contact point on the board for transforming electrical signals between the component or the module and the board. The outer pad area or pad ring 6 constitutes the sacrifice pad area or pad ring and has normally no electric contact function, but any pad in this pad area or pad ring can in addition be used as test point/points in a production line, wherein individual pads of the sacrifice pad area or pad ring can be used as internal test points and in most cases their existence has no use for a final user. Pads in the sacrifice pad area or pad ring can be broken as open circuits and this will in most cases not effect the operation of the component or the module.
[0011] In FIG. 3 a rectangular component or module 7 is shown, where only 4 inner pads 8 are surrounded by an outer pad area consisting of 48 pads 9 . The inner pads 8 are provided to be ordinary pads, which function to be connected to a board with corresponding contact points on the board, wherein each pad on the component or the module enables contact with a corresponding contact point on the board for transforming electrical signals between the component or the module and the board. The outer pad area 9 constitutes the sacrifice pad area and has normally no electrical contact function, but any pad in the pad area can in addition be used as test point/points in a production line, wherein individual pads of the sacrifice pad area can be used as internal test points and in most cases their existence has no use for a final user. Pads in the sacrifice pad area can be broken as open circuits and this will in most cases not effect the operation of the component or the module.
[0012] The mechanical lifetime of a component or module will be increased due to the existence of a sacrifice pad area or pad ring. The sacrifice pad area or pad ring gives for the first the inner connections points a functioning mechanical protection against horizontal and/or vertical loads. When performed rapid temperature change tests parts of the outer pad area or pad ring will for the second be the first destroyed part of the component or the module before any part of the inner part inside the pad area or pad ring will be destroyed. With the outer pad area or pad ring it will be easy to determine the mechanical life time of the component or the module, only by detection and registration under fatigue test or performed rapid temperature change test when the first pad of the sacrifice pad area or pad ring will be destroyed a very well defined life time of the component or the module can be determined. At the tests the pad in any corner of the pad area or pad ring on the component or the module will be firstly destroyed and then the adjacent placed pads will be destroyed and so on, because the mechanical stress has a maximum in the corners of the component or the module.
[0013] With a sacrifice pad area or pad ring, where every formed pad in the pad area or pad ring is grounded, a grounded screening cage can be achieved, which electrically protects the electronic circuits and elements of the component or the module placed inside of the pad area or pad ring. It is even more economical and easy to produce a sacrifice pad area or pad ring consisting of many individually placed pads in line compared with a metal bar on the board, when producing hundreds of ordinary pads on a component or module, of which the outer pads function to be the sacrifice pad area or pad ring of the component or the module. The mechanical protection is easy to produce together with the other pads. With the outer pads in the sacrifice pad area or pad ring of the component or the module connected to the board it is even possible to visually inspect the connected pads inside the pad area or pad ring to determine the quality of the connections compared with if there is a homogenous pad ring or bar outside the inner connected pads. If the quality of the pads of the pad area or pad ring can be determined the quality of the inner pads can be estimated based on the observations of the pads of the pad area or pad ring. Without the pad area or pad ring it is difficult to determine or estimate the quality of the connections of the inner pads.
[0014] For high frequency module application a measuring of the return loss of the antenna port can monitor the condition of the sacrifice pad area or pad ring. The sacrifice pad area or pad ring can be connected to ground and when the sacrifice pad area or pad ring grounds start to diminish, then this can be monitored by an increased return loss on the antenna port and there will be a risk for damage of the component or the module.
[0015] In order to place a component or module 10 correct on a board a single pad 11 can be removed from the sacrifice pad area or pad ring 12 , see FIG. 4 , without essentially influencing the effect of the grounded screening cage. Due to the asymmetry the user of the component or the module can not place the device 180 degrees incorrect. With the asymmetry and the removed pad from the sacrifice pad area or pad ring sensitive module signals such as RF and balanced data lines are not required to be routed through several layers. The sensitive signals can be routed on a top layer of the board directly to a connection point or pad 13 on the mounted module.
[0016] When a component or module is assembled onto a board, the purpose of the sacrifice pad area or pad ring is to increase the mechanical lifetime of the component or the module. The mechanical lifetime is usually measured by performing rapid temperature change tests. After certain number of temperature cycles in a lifetime test environment the outer region of the pad area or the pad ring will start to break first. This will not effect the performance of the component or the module since all the electrical interconnects are in the centre of the LGA. The using of the sacrifice pad area or pad ring concept will increase the mechanical lifetime of the component or the module and may provide an additional number of test points in combination with detection devices for example in a production line.
[0017] It will be obvious that the invention may be varied in many ways. Such variations are not to be regarded as a departure from the scope of the invention. All such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the appended claims. | A connectivity from a module to a board is ordinary achieved with pads as via Land Grid Array (LGA), where an inner area of the module is provided with pads designated for electrical connectivity to corresponding points of connection on the board. To protect the component or the module and to increase the mechanical life time of the component or the module, the outer area of the component or the module ( 1) is provided with a peripheral outer line of pads forming a sacrifice pad area or pad ring ( 3), where individual pad or pads can be sacrificed without destroying the inner pads ( 2), which are designated for the electrical connectivity to corresponding points of connection on the board provided inside the sacrifice pad area or pad ring on the component or the module. |
RELATED APPLICATION
This application is a continuation-in-part of U.S. patent application Ser. No. 07/607,549, filed Nov. 1, 1990 and now abandoned, which is a continuation of U.S. Ser. No. 416,924, filed Oct. 4, 1989, now U.S. Pat. No. 4,987,893, issued Jan. 29, 1991, which is a continuation-in-part of U.S. patent application Ser. No. 07,256,651, filed Oct. 12, 1988 now abandoned.
BACKGROUND OF THE INVENTION
The invention pertains to liquid adhesive materials which are useful for protecting surfaces such as bioloqical surfaces, including skin and mucous membranes. The polymer component of the liquid adhesive material comprises an ethylenically unsaturated addition polymerizable monomer containing at least one alkyl siloxy silane. The polymer may also include other monomers.
The polymer, when incorporated into volatile liquid polydimethylsiloxanes, preferably with a small amount of polar liquids or solvents, provides for a fast drying, flexible, waterproof, breathable, non-stinging liquid adhesive coating or bandage. This liquid adhesive coating may contain medicants or other active materials which may be qradually released onto tarqeted areas, if desired.
PRIOR ART
Naturally occurring and derivatized naturally occurring polymers have been tested as liquid adhesive coatings for bandage applications and, in some cases, utilized commercially. Typical examples are nitrocellulose in various solvents (e.g., New Skin-Medtech Laboratories, Inc., Cody, Wyoming), agar in water and diethylene glycol (U.S. Pat. No. 4,291,025) carrageenan and hydroxypropylmethyl cellulose in water (U.S. Pat. No. 4,318,746), and alginate in glycerin (U.S. Pat. No. 4,393,048). All of these natural polymers can support microbial growth, hence requiring the addition of a preservative or antimicrobial agent to the product. The liquid bandages based on water, diethylene glycol, glycerin, etc. are not only susceptible to microbial growth, but are often also slow drying due to high heats of vaporization; and are often water sensitive, which can result in problems when used on areas of the body exposed to water. One commercial product, New Skin, does dry rapidly and is not water sensitive, but can cause stinging and further irritation of the skin upon application.
A few synthetic polymers have been patented for use as liquid adhesive coatings for bandage applications, most notably polymers containing 2-hydroxyethyl methacrylate (U.S. Pat. No. 4,303,066). These bandages based on the use of solvents can sting abraded areas; and the films can swell and wash off when in contact with water. U.S. Pat. No. 4,569,784 claims an ointment, not a long lasting bandage composed of an emulsion of water and silicone fluids, among other fluids. This reference can provide for an immediate soothing, but often not long lasting, treatment of the skin or mucous membranes. It also does not provide for fast drying, abrasion resistance, and other attributes which a polymer film can provide.
Additionally, traditional wound and surgical bandages, such as Band Aids (Johnson & Johnson, New Brunswick, NJ), comprised of film backings with adhesive, may contain silicones as part of either the adhesive or the backing (e.g. U.S. Pat. No. 4,650,817). These products are not applied as liquid adhesive coatings where films form and adhere directly on the skin.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a liquid polymer-containing coating material which can act as a bandage or dressing to protect wounds, when applied in liquid form and air dried on the wound to form an adherent, solid protective film without significant stinging to the skin or mucous membranes of the user.
It is a further object of the invention to provide a coating which will prevent further microorganism or particulate contamination to skin or mucous membrane wounds or incisions.
It is a further object of the invention to provide a non tacky, transparent covering which does not attract or hold dirt and can remain colorless and clear for wound viewing as well as cosmetic attractiveness.
It is a further object of the invention to provide a coating which, when applied, will control body fluid loss from an abraded area.
It is a further object of the invention to provide a polymer film in which medicants or other active agents, e.g. perfumes, may be incorporated for gradual release into targeted areas.
It is a further object of the invention to provide a coating which, when applied, repels liquid H 2 O, but also allows H 2 O vapor to pass through. It is a further object of the invention to provide a low surface tension covering which can reduce drag.
The liquid polymer-containing coating materials of this invention consist essentially of a siloxane containing polymer and a solvent system comprising a polar solvent in small amount and a volatile liquid which is non stinging to a user but provides bulk and formability to the liquid. Preferably the polymer is present from 1 to 40% by weight, the volatile liquid from 59.9 to 98.9% by weight and the polar solvent from 0.1 to 10% by weight. When the polar solvent is eliminated, the volatile liquid can be in amounts of 60 to 99%. The solvent is minimized to obtain flowability desired at the lowest solvent level feasable which minimizes stinging. The material forms a coating or bandage in the form of a dried film when applied to a surface or the skin of a user.
Preferably, the siloxane containing polymer comprises at least one vinyl containing alkylsiloxysilane and an addition polymerizable comonomer. The volatile liquid is preferably a polydimethylsiloxane.
It is a feature of the invention that the liquid materials can act at room temperature (20° C) when applied to skin, nails, or mucous membranes of a user to form films in minutes, which films are excellent bandages. They are not a nutrient source for microorganisms, are conformable, comfortable and can be elastic and flexible. The films do not irritate the skin and mucous membrane when sprayed or deposited in any way during application and in use after drying. The bandages are substanially painless and can be easily removed substantially without pain. The dried bandages formed are substantially non water sensitive, and waterproof and have high water vapor and oxygen gas transmission therethrough. The bandages form when applied over surfaces wet with water , blood or body fluids, in short times at standard room temperature and reasonable varients thereof. The liquid composition and/or dried polymer film can have various medicaments or other agents incorporated therein for maintaining sterility and/or for release to the underlying area of the body of a user. For example, perfumes, antibacterial or similar materials can be released from the coatings.
DESCRIPTION OF PREFERRED EMBODIMENTS
The siloxane containing polymers of this invention can comprise vinyl containing alkylsiloxysilanes alone or as co , ter or multi component polymers which can include other polymerizable monomers that do not make the polymers hydrophilic.
Typical vinylalkylsiloxysilanes that may be utilized are:
3-methacryloyloxypropyltris(trimethylsiloxy)silane (TRIS);
3-methacryloyloxypropylpentamethyldisiloxane;
3-methacryloyloxypropylbis(trimethylsiloxy)methylsilane;
3-acryloyloxypropylmethylbis(trimethylsiloxy)silane;
3-acryloyloxypropyltris(trimethylsiloxy)silane; and others.
Typical addition polymerizable monomers which may be reacted with the vinylalkylsiloxysilanes to form multipolymers are: methyl methacrylate methyl acrylate, tetrahydrofurfuryl methacrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, n lauryl acrylate, n lauryl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, isodecyl acrylate, isodecyl methacrylate, isooctyl acrylate, isooctyl methacrylate, isobornyl acrylate, isobornyl methacrylate, benzyl methacrylate, 2-butoxyethyl acrylate, n butyl acrylate, n butyl methacrylate, ethyl acrylate, ethyl methacrylate, dimethyl itaconate, di-n butyl itaconate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, furfuryl methacrylate, n hexyl acrylate, n hexyl methacrylate, isobutyl acrylate, isobutyl methacrylate, isopropyl methacrylate, methyl acrylate, alpha methyl styrene, styrene, p-t-butyl styrene, 4-methoxystyrene, n octadecyl acrylate, n octadecyl methacrylate, 2-phenylethyl methacrylate, n tridecyl methacrylate, vinyl benzoate, vinyl naphthalene. In addition fluorinated siloxanes, fluorinated itaconates, fluorinated methacrylates or acrylates, such as hexafluoroisopropyl methacrylate, can be used.
Any hydrophobic polymerizable monomer can be used as long as the resulting copolymer has desired O 2 and H 2 O vapor permeability. These additional polymerizable comonomers can be present in amounts up to 0.85 mole fraction.
The polymers of the invention are preferably in proportions between about 15-100 mole % vinylalkylsiloxysilane which component maintains the desired compatibilty of the polymer in the volatile liquid polydimethylsiloxanes with polar additives, provides high moisture and oxygen permeability, and provides biocompatibility. A range of 20 to 40 mole of the vinylalkylsiloxysilane in the polymer is preferred in the polymer of this invention. Other addition polymerizable monomers may be copolymerized with the vinylalkylsiloxysilanes between about 0-85% mole of the polymer composition to adjust permeability, adhesion, toughness, elasticity, temperature stability, and impact resistance, among other film gualities.
The polymers may be linear, branched, or slightly cross linked and can be homo , co-, ter- or multi polymers. They may be random copolymers or segmental in nature.
Typical vinylalkylsiloxysilane monomers can have the following formulas:
CH.sub.2 ═C(R.sup.1)COOR.sup.2 SiR.sup.3 R.sup.4 R.sup.5
Where R 1 =H,
CH 3 , or
CH 2 COOR',
Where R 2 =alkyl (C 1 -C 4 ) or CH 2 CH(OH)CH 2 ,
Where R 3 , R 4 , R 5 =OSi(Y) 3 , or alkyl (C 1 -C 6 ),
Wherein, at least one of R 3 , R 4 , R 5 =OSi(Y) 3
Where Y=alkyl (C 1 -C 6 ), OSi(Z) 3 or
R 2 OOC(R 1 )C═CH 2 ,
Where Z=alkyl (C 1 -C 6 ), aryl, and
Where R'=R 2 SiR 3 R 5 R 5
The polymers may have molecular weights from 50,000 to several million. The preferred molecular weight range is 50,000 to 500,000 weight average molecular weight. Lower molecular weight polymers have notably higher solubility in the solvents and solvent systems of this invention and hence, while they can be film formers, they generally are slow to dry and remain tacky. Higher molecular weight polymers are not soluble or dispersable in the solvents or solvent systems of this invention and therefore do not provide optimum film formation or flow properties. It is important for guick, non tacky drying of the wound dressing that the polymer be in a poor solvent system. This is achieved by monomer choice, molecular weight control, and solvent system choice. The molecular weight of the polymers may be controlled by varing initiator, initiator concentration, reaction temperature, reaction solvent, and/or reaction method.
Most preferably, the polymers of the invention are acrylate or methacrylate terpolymers having an "A" monomer component that is a silane derivative, a "B" monomer component that when provided as a homopolymer would prepare a "hard" polymer, and a "C" monomer component that, when provided as a homopolymer would prepare a "soft" polymer.
For the A monomer, examples of the silane derivatives are as described above. B monomers are "hard" where the corresponding homopolymer typically has a T g of more than about -5° C. Examples of such monomers are acrylate or methacrylate monomers, preferably C 1 -C 4 alkyl methacrylates. Most preferably, the hard monomer is methyl methacrylate.
Other examples of monomers that can be used for the hard monomer component are monomers having the reguisite T g values including methacrylates having a structure other than delineated above, such as benzyl methacrylate and isobornyl methacrylate methacrylamides such as N t butylmethacrylamide; acrylates such as isobornyl acrylate; acrylamides such as N butylacrylamide and N-t butylacrylamide; diesters of unsaturated dicarboxylic acids such as diethyl itaconate and diethyl fumarate; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate; and monomers containing an aromatic ring such as styrene; α methyl styrene and vinyl toluene. C monomers may be selected from monomers that form soft homopolymers. "Soft" monomers are monomers where the corresponding homopolymer typically has a T g of less than about 10° C. Such monomers are C 4 -C 12 alkyl acrylates and C 6 -C 12 alkyl methacrylates, wherein the alkyl roups are straight, branched, or cyclic. Most preferably, the soft monomer is selected from C 7 -C 10 straight chain alkyl acrylates.
Other examples of monomers that can be used for the soft monomer component are monomers having the reguisite T g values including dienes, such as butadiene and isoprene; acrylamides, such as N-octylacrylamide; vinyl ethers such as butoxyethylene, propoxyethylene and octyloxyethylene; vinyl halides, such as 1,1-dichloroethylene; and vinyl esters such as vinyl caprate and vinyl laurate.
It has been found that this mix of monomers provide particularly advantageous abilities to adjust mole fraction ratios to optimize oxygen permeability, ductility, moisture vapor transmissability of the film and cost of materials, with more mole fraction ratios being soluble in the preferred polydimethylsiloxane solvent. Highly durable coatings are particularly desired to enable the coating to remain on the skin for an extended time and to provide superior protection.
Most preferably, the siloxane containing polymer comprises about 50 to 60 weight percent of A monomer, about 25 to 45 weight percent B monomer, and about 3 to 20 weight percent of C monomer. A specifically preferred embodiment is where the siloxane-containing polymer comprises about 50 to 60 weight percent of 3 methacryloyloxypropyl tris(trimethylsiloxy)silane, about 25 to 45 weight percent methyl methacrylate, and about 3 to 20 weight percent of a monomer selected from C 7 -C 10 straight chain alkyl acrylates.
One variation in selection of monomers to be used in the siloxane containing polymer is using more than one monomer within each catagory A, B or C. For example, the polymer could comprise 57% 3 methacryloyloxypropyl tris(trimethylsiloxy)silane, 39% methyl methacrylate, 2% isooctyl acrylate and 2% decyl acrylate. The last two monomers each satisfy the definition of the C monomer, and together provide the desired guantity of this component.
Any free radical initiator can be used in forming the polymers including azobisisobutyronitrile; 2,2'-azobis (2,4 dimethylpentanenitrile); 2,2'-azobis- (2-methylbutanenitrile); potassium persulfate; ammonium persulfate; benzoyl peroxide; 2,5-dimethyl 2,5-bis (2-ethylhexanoylperoxy) hexane; and the like. The polymerization can be carried out by solution, emulsion, or suspension technigues.
The polymers of the invention are incorporated into a solvent system comprising volatile liquid silicones, preferably polydimethylsiloxane (preferably having a solubility parameter of 6.8 -7.2 (cal/cm 31/2 ) and if desired, a small amount (0.1-10 wt %) of polar liquid (preferably having a solubility parameter greater than or egual to 9 (cal/cm 31/2 ). By utilizing a solvent system of this nature, the cast films dry more rapidly and are less sticky during drying. Moreover, the polar liquid or solvent can be used in minimized amount to minimize stinging. Volatile polydimethylsiloxanes (e.g. hexamethyl disiloxane (HMDS), octamethyl cyclotetrasiloxane (D 4), decamethyl cyclopentasiloxane or octamethyl trisiloxanes and the like), are non stinging, have a low heat of vaporization, are inert, and are non irritating. The use of these liquids simply or in combination as the primary liquid phase of the liquid coating provides for comfort to a wounded area when used as a bandage, rather than further irritation and also allows for a higher oxygen and moisture vapor permeation rate while present.
Solubility parameters can be measured in a number of different ways, resulting in different values. The solvents used in the present invention are reported to have solubility parameters of about 6.8-7.2 (cal/cm 3 ) 1/2 in Dow Corning trade literature. These values are based on empirical methods for estimating solubility parameters. Another method of measuring the solubility parameter of volatile solvents is to directly compute from the heat of vaporization, as taught by the Polymer Handbook, Second Edition, Brandup and Immergut, Solubility Parameter=(Heat of Vaporization RT)/Molar Volume. Using this formula, the solubility parameter of HMDS is 5.7 (cal/cm 3 ) 1/2 , and for D4 is 5.4 (cal/cm 3 ) 1/2 . The polar liquid or solvent when used preferably is a substance with a solubility parameter greater than or egual to about 11.0 (cal/cm 31/2 ), such as: ethanol, 95% ethanol 5% water, isopropanol, propanol, diethylene glycol, propylene glycol, ethylene glycol, N methyl pyrrolidone or glycerol. Alcohols, esters, such as acetates, and organic acids, such as acetic acid, can also be used as the polar solvent. The polar liquids can function to further chain extend the polymer incorporated into the liquid polydimethylsiloxanes. The polydimethylsiloxanes are not true solvents for the polymers of the invention and the preferred polar liquids are solvents. The combination of the polydimethylsiloxanes and the polar solvents causes the polymers to chain extend and flow as liquids. In some cases, the polar liquid need not be used where solubility modification is not required. When polymers of the invention are of lower molecular weight in the range of 100,000 or lower, they generally can be incorporated into the polydimethylsiloxane solvent without the addition of adjunctive polar solvent. Also, if the polymers of the invention are not purified by precipitation, but rather distillation, when the reaction liquor is polydimethysiloxane, the polymers of the invention remain incorporated and do not require adjunctive polar solvent. Thus, the coating of this invention can be made without the use of polar liquids in some cases. The polymers can be synthesized in the organic liquid such as neat hexamethylene disiloxane, without precipitation or separation of the polymer phase. The unreacted monomers can then be distilled out of the reaction liquor, after polymerization is essentially complete, leaving the polymer dissolved in the reaction liquor to produce useful, non toxic coating compositions.
Polymer films of the invention cast from liquids containing good solvents with solubility parameters of between about 9 to 10 (cal/cm 31/2 ), (e.g. tetrahydrofuran and ethyl acetate) will function, but are generally slow to dry and remain tacky for extended periods.
Other substances may be added to the liquid material or formulation for plasticization, improved adhesion, or rheology control, and the like. Typical plasticizer/adhesion promoters are dibutylphthalate, acetyl tributyl citrate, sucrose acetate isobutyrate, sucrose benzoate, acetyltriethyl citrate, mineral oil, decamethyl cyclopentasiloxane, octamethyl cyclotetrasiloxane, butyl glycolate, and others.
Typical rheology additives that may be utilized are fumed silica, bentonite and other clay derivatives,and saturated fatty acids, such as hydrated ricinoleic acid.
The liquid adhesive material, composed of the polymer, solvent system, and additives, is useful for protecting or treating skin, nails and mucous membranes, e.g., skin cuts, abrasions, incisions and blisters; dry cracked skin; abraded gums and other oral sufaces; hemorrhoids and abraded body areas; inflammed digestive tract; and, other mucosal membrane incision and wounds.
As the liquid bandage is non stinging and instantly covers exposed nerve endings, pain is stopped immediately. The bandage remains adherent to the skin/mucosal surface for 1-3 days, relieving pain and gradually lifting off without creating damage or further irritation.
Normal unabraded skin looses moisture vapor at an average rate of 200 g/m 2 /day in most areas; the palms of the hand and soles of the feet respire at an average of 500 g/m 2 /day. The liquid adhesive bandages of this invention have moisture vapor transmission rates of 200-700 g/m 2 /day depending on protective polymer film thicknesses (0.0005-0.010 inches), thus preventing both dehydration of wounded areas and occlusion of body fluids. The polymers of this invention have exceptional oxygen permeability (DK) of about 120× 10 -11 (cm 2 /sec) (ml O 2 /ml mm Hg) and the liquid adhesive coatings and bandages incorporating these polymers have oxygen permeability of about 80 ×10 -11 (cm 2 /sec) (ml O 2 /ml mm Hg) at 35° C.
The liquid adhesive coatings of this invention may be applied to the skin, mucous membranes, etc. in liquid form by utilization of a brush, rod, finger, sponge, cloth, dropper, etc; in spray or mist form; or any other usable technigue for applying a liquid to a surface.
Medicants may be incorporated into the liquid or solid, dried film bandages for ready or continual release as the invention provides for an inert, longlasting, highly permeable film which can contain medicant or other active agents to be applied to the skin, mucous membranes, and other body areas on which it is desired to release the active agent over an extended period of time. Examples of useful medicants are fungicides, antibacterial agents, antiviral agents, antitumor agents, blood pressure and heart regulators, and many more. Other types of active agents which may be desirable to incorporate include perfumes, plant growth regulators, plant insecticides, UV and IR absorbers, etc.
The liquid adhesive coating of this intention could be used for applications other than medical body care. For instance, the coating could be used as a water repellent, yet H 2 O vapor permeable, film applied to sanitary napkins, diapers, or panties. With the incorporation of mildewcides, the liquid adhesive coating could be used to cover grout in tiled surfaces. The liquid adhesive is also useful as an insulative layer in the manufacture of electronic devices such as printed circuits, integrated circuits and interconnects. The liquid adhesive coating is further useful as a sunscreen with the incorporation of UV absorbers. Still other uses include forming films for use in eliminating chapped lips, treating skin and internal body surfaces, and providing protection to skin and other surfaces which may be medicated prior to application.
The following examples and test results are illustrative of the invention but are not meant to be limiting thereof:
EXAMPLE 1
A 500 ml resin kettle with overhead stirrer, N 2 inlet, condenser, and oil bath was set up in a hood. 14.25 g (0.034 mol) of 3-methacryloyloxypropyl tris(trimethylsiloxy)silane (TRIS) and 0.75 g (0.008 mol) of methyl methacrylate were dissolved in 150 g ethyl acetate. After charging this solution to the resin kettle and heating to 78° C., a solution of 0.15 g azobisisobutyronitrile (AIBN) in 10 g ethyl acetate was charged. The polymerization ran for 4 hours at 78° C. The low molecular weight product was precipitated into methanol, oven dried and dissolved in hexamethyl disiloxane. When cast onto glass, the polymer in hexamethyl disiloxane produced an adherent, tacky film which can be used as a pressure sensitive adhesive for a variety of substrates such as glass, or can be used as an adhesive for a bandage of cloth or plastic substrate.
EXAMPLE 2
A 50 ml reaction flask was charged with 2.5 g ethyl acetate, 2.5g (0.006 mol) (TRIS) and 0.09 g 2,5 dimethyl 2,5 bis(2-ethylhexanoylperoxy)hexane; flushed with nitrogen for 15 minutes, and completely closed to air. The polymerization was run for 94 hours at 65° C. The low molecular weight product when cast provided an elastic, waxy continuous film which was readily soluble in hexamethyl disiloxane.
EXAMPLE 3
To a 50 ml reaction flask was charged 19.76 g ethyl acetate, 4.28 g (0.010 mol) TRIS, 0.78g (0.008 mol) methyl methacrylate, 0.29 g (0.002 mol) cyclohexyl methacrylate, and 0.003 g azobis(isobutyronitrile). The reaction mixture was flushed with nitrogen for 20 minutes and then stoppered. The polymerization was run at 60-°70° C. for approximately 10 days. A film cast from the mother liquor was non-tacky, elastic, and relatively tough. The dried polymer was marginally soluble in hexamethyl disiloxane.
EXAMPLE 4
To a 50 ml reaction flask was charged 20.16 g ethyl acetate, 2.51 g (0.006 mol) TRIS, 2.01 g (0.02 mol) methyl methacrylate, 0.25 g (0.001 mol) 2-ethylhexyl acrylate, and 0.003 g azbis(isobutyronitrile). The reaction mixture was flushed with nitrogen and then stoppered. The polymerization was run at 60°-70° C. for 4 days. A film cast from the mother liquor was clear, adherent, flexible and tough. The dried polymer was marginally soluble in hexamethyl disiloxane. A 0.016 in. thick film cast from the mother liquor had a moisture vapor transmission rate of 83 g/m 2 /24 h; a 0.0045-0.005 in. thick film had a moisture transmission rate of 126 g/m 2 /24 h; and, a 0.0025-0.003 in. thick film had a moisture vapor transmission rate of 180 g/m 2 /24 h.
EXAMPLE 5
To a 50 ml reaction flask was charged 19.19 g ethyl acetate, 2.2 g (0.005 mol) TRIS, 3.78 g (0.027 mol) n-butyl methacrylate, and 0.002 g azobisisobutyronitrile. After flushing with nitrogen, the flask was stoppered, the reaction run at 60°-70° C. for 6 days. The resultant polymer was precipitated into methanol and dried at 110° C. for 4 hours. The dried polymer was incorporated into hexamethyl disiloxane. A 0.025 in. thick film of the polymer cast from the mother liquor gave a moisture vapor transmission rate of 37.9 g/m 2 /24 h.
EXAMPLE 6
A 500 ml resin kettle, eguipped as in Example 1, was charged with 27.40 g (0.065 mol) TRIS, 18.54 g (0.185 mol) methyl methacrylate, 4.10 g (0.022 mol) 2-ethylhexyl acrylate, and 194 g ethyl acetate. After heating to 48° C., 0.01 g of 2,2'-azobis (2,4-dimethylpentanenitrile) dissolved in 3.09 g ethyl acetate was added and the polymerization run for 16 hours. At which time, 0.01 g of 2,2 azobis (2,4 dimethylpentanenitrile) dissolved in 3.09 g ethyl acetate was again added to the reaction continued to run for another 24 hours. The product was precipitated in methanol and air dried. The dried product was partially soluble in hexamethyl disiloxane.
EXAMPLE 7
Preciptated and dried polymer (1.02 g) from Example 6 was dissolved in 4.02 g ethyl acetate, when cast into a 0.004 in film, provided a moisture vapor rate of 126 g/m 2 /42 h
EXAMPLE 8
Preciptated dried polymer (1.01 g) from Example 6 was dissolved in 5.40 g ethyl acetate with sucrose acetate isobutyrate (0.34 g). This formulation provided an adherent, non tacky film with a moisture vapor transmission rate of 180 g/m 2 /24 h at a 0.0035 in. film thickness, and 613 g/m 2 /24 h at 0.0005 0.001 in. film thickness.
EXAMPLE 9
Precipitated dried polymer (1.05 g) from Example was dissolved in 5.44 g ethyl acetate and 0.31 g decamethyl cyclopentasiloxane, and then cast into a 0.004 in. film provided a moisture vapor transmission rate of 180 g/m 2 /24 h.
EXAMPLE 10
Precipitated dried polymer (1.04 g) from Example was dissolved in 6.76 g ethyl acetate and 0.65 g decamethyl cyclopentasiloxane, and when cast into a 0.0002 in. film provided a moisture vapor transmission rate of 866 g/m 2 /24 h.
EXAMPLE 11
A 50 ml reaction flask was charged with 30 g ethyl acetate, 5 g (0.012 mol)TRIS, 0.8 g (0.004 mol) 2-ethylhexyl acrylate, 4.2 g (0.029 mol)n butyl methacrylate, and 0.4 g of a 0.36% solution of 2,2 -azobis(2,4 dimethylpentanenitrile) in ethyl acetate. After nitrogen flushing for 20 minutes, the flask was stoppered and placed in a 40° C. oven for 5 days. After precipitation in methanol and air drying, the resultant polymer was soluble in hexamethyl disiloxane containing some methanol.
EXAMPLE 12
To a reaction, eguipped as in Example 1, was charged 10.35 g (0.025 mol) TRIS, 3.87 g (0.039 mol) methyl methacrylate, 3.87 g (0.034 mol) ethyl methacrylate, 0.02 g 2,2'-azobis (2 methyl butanenitrile), and 42.0 g hexamethyldisiloxane (HMDS). The polymerization was run 6 hours at 80° C. and then terminated by the addition of air. The polymer was precipitated into cold methanol with a resultant 86% yield of polymer. Films (0.0014-0.0018 in. thick) cast from the mother liquor produced moisture vapor transmission rates of 630 g/m 2 /24 h.
EXAMPLE 13
To a reaction, eguipped as in Example 1, was charged 49.5 g (0.117 mol) TRIS, 20.0 g (0.2 mol) methyl methacrylate, 20.7 g (0.18 mol) ethyl methacrylate, 0.08 g 2,2'-azobis(2 methyl butanenitrile), 105.01 g 95% ethanol, and 105.03 g HMDS. The polymerization was run for 24 hours at reflux, 74° C. The polymer was then precipitated into water, washed repeatedly, and oven dried at 250° F. for 6 hours to produce an 86% yield. The resultant polymer had a of 164,200, M n of 114,600 and a polydispersity ratio of 1.43.
EXAMPLE 14
A 1000 ml resin kettle eguipped as in Example 1 was charged with 210 g hexamethyl disiloxane, 210 g 95% ethanol, 99.21 g (0.235 mol) TRIS, 40.09 g (0.400 mol) methyl methacrylate, 40.09 g (0.351 mol) ethyl methacrylate, and 0.16 g 2,2'-azobis-(2 methylbutanenitrile) and the reaction ran at 75° C. for 22 hours. The polymer was then precipitated into water and dried for 12 hours at 110° C. to give an 89% yield. When incorporated into 435 g hexamethyl disiloxane and 5.06 g 95% ethanol, the polymer (65.80 g) provided a cast film with an oxygen permeability of 120×10 11 (cm 2/ sec) (ml O 2 /ml mm Hg) at 35° C. EXAMPLE 15
The polymer (1.26 g) of Example 14 was incorporated into a liquid adhesive bandage composition composed of 0.10 g 95% ethanol, 0.15 g sucrose acetate isobutyrate, 8.22 g hexamethyl disiloxane, and 0.01 g Thixin R (NL Chemicals, Hightstown, NJ). The resultant cast film, after two weeks of aging at room temperature, has an oxygen permeability f 80×10 -11 (cm 2 /sec) (ml O 2 /ml mm Hg) at 35° C.
EXAMPLE 16
The resultant dried polymer (2.34 g) from Example 14 was added to 15.30 g hexamethyl disiloxane, 0.36 g ethanol, and 0.18 g sucrose acetate isbutyrate. Films (0.002 0.003 in. thick) cast from this liquid coating formulation produced moisture vapor transport rates of 340 +/-20 g/m 2 /24 h.
EXAMPLE 17
To 3.97 g of polymer prepared as in Example 14 were added 0.29 g 95% ethanol, 0.61 g octamethyl cyclotetrasiloxane, 0.29 g sucrose acetate isobutyrate, and 23.65 g hexamethyldisiloxane. The liquid adhesive bandage composition produced moisture vapor transport rates of 285 g/m 2 /24 h from a 0.004 in film, 560 g/m 2 /24 hr from a 0.001 in film, and 610 g/m 2 /24 hr from a 0.0005 in film.
EXAMPLE 18
Liguid adhesive coating formulations prepared as in Example 17 were used on numerous occasions on minor cuts and abrasions by male and female human adults for the relief of pain. In each case, wound pain was relieved immediately upon application of the liquid bandage. The individuals had full use of the wounded areas without pain during healing.
EXAMPLE 19
An adult male accidentally cut off the tips of his right middle and index fingers excising at least the epidermis and the dermis; he applied the liquid bandage formulation as prepared in Example 17 and found immediate complete relief from pain. He reapplied the bandage once a day. During healing he had full use of his fingers without pain. The wound did not form a scab and healed without scarring.
EXAMPLE 20
An adult male accidentally sheared off the back of one of his teeth exposing the nerve. Upon application of the liquid bandage, as prepared in Example 17, he found immediate relief of pain. He applied the bandage once a day for two days until he could see a dentist for repair to the tooth. The bandage remained adherent to the tooth and surrounding gingival and periodontal tissue during utilization.
EXAMPLE 21
Two teenage males and one teenage female covered poison ivy inflammations with a liquid bandage, prepared as in Example 17 except in aerosol form, and found immediate complete relief from itching. They treated the poison ivy throughout its term and were not bothered by itching.
EXAMPLE 22
An adult male accidentally cut himself with a knife on his left index finger, upon applying liquid bandage prepared as in Example 17, the wound pain was relieved immediately. The wound healed in two to three days with no scab formation or scarring.
EXAMPLE 23
An adult male applied a liquid bandage, prepared as in Example 17 except in aerosol form, to hemorrhoids and obtained relief from the pain caused by the condition.
EXAMPLE 24
An adult male applied a liquid bandage, prepared as in Example 17 except in aerosol form, to mosguito bites and completely relieved all itching associated with these bites.
EXAMPLE 25
To 22.08 g of liquid bandage prepared as in Example 17 was added 0.41 g of isopropyl xanthic disulfide, a fungicide. The isopropyl xanthic disulfide was completely soluble in the liquid bandage formulation both in liquid form and when dried. The dried film was transparent yellow in color.
EXAMPLE 26
A 1000 ml. reaction kettle eguipped with an overhead stirrer, N2 purge, condenser, and heating mantle is charged with 70 g hexamethyl disiloxane, 16.5 g (0.039 mol.) TRIS, 13.2 g (0.132 mol.) methyl methacrylate, 0.30 g (0.002 mol.) isooctyl acrylate, and 0.026 g 2,5 dimethyl 2,5 bis(2-ethyl hexanoylperoxy)hexane is charged. After the reaction is terminated by the addition of air and lowering of temperature, the reaction liquor is added to water. The hexamethyldisiloxane is evaporated and the precipitated polymer dried at 105° C. for 12 hours to give a 64% yield. The resultant polymer (2.99 g) when incorporated into 11.96 g hexamethyldisiloxane and .04 g. 95% ethyl alcohol produces a tough, elastic, adherent film.
EXAMPLE 27
The reaction of Example 26 is terminated after 18 hours at 74° C. by the addition of air. The temperature is then raised to 100° C. to allow distillation of the hexamethyldisiloxane containing unreacted methyl methacrylate and isooctyl acrylate. The distillate is filtered through a charcoal containing column to trap unreacted monomers and circulated back to the reaction kettle. The resultant purified liquid product produces a tough, elastic, adherent film when cast.
EXAMPLE 28
To a 50 ml reaction vessel was charged 20.22 g ethyl acetate, 3.04 g (0.007 mol) TRIS, 1.99 g (0.02 mol) methyl methacrylate, and 0.61 g (0.003 mol) 2-ethylhexyl acrylate, and 0.003 g azobis(isobutyronitrile). The reaction mixture was flushed with nitrogen for 20-25 minutes and then stoppered. The polymerization was run at 60 70° C. for 5 days. A film cast from the mother liquor was adherent to glass, clear, elastic and tough. The dried polymer was soluble in hexamethyl disiloxane.
EXAMPLE 29
To a 50 ml reaction vessel was charged 20.28 g ethyl acetate, 2.96 g (0.007 mol) TRIS, 1.99 g (0.002 mol) methyl methacrylate, and 0.36 g (0.002 mol) 2-ethylhexyl acrylate, and 0.003 g 2,2'-azobis(2,4 dimethylpentane nitrile). The reaction mixture was flushed with nitrogen for 20 minutes and then stoppered. The polymerization was run at 40 55° C. for 4 days. The dried polymer was soluble in hexamethyl disiloxane.
EXAMPLE 30
To a 50 ml reaction vessel was charged 19.48 g ethyl acetate, 4.25 g (0.01 mol) TRIS, 0.91 g (0.009 mol) methyl methacrylate, and 0.10 g (0.001 mol) cyclohexyl methacrylate, and 0.003 g azobis(isobutyronitrile). The reaction mixture was flushed with nitrogen for 20 minutes and then stoppered. The polymerization was run at 60°-70° C. for approximately 10 days. A film cast from the mother liquor was tacky, and elastic. The dried polymer was slowly soluble in hexamethyl disiloxane.
EXAMPLE 31
To a 50 ml reaction vessel was charged 19 g ethyl acetate, 4.25 g (0.01 mol) TRIS, 0.50 g (0.005 mol) methyl methacrylate, and 0.54 g (0.003 mol) cyclohexylmethacrylate, and 0.003 g azobis(isobutyronitrile). The reaction mixture was flushed with nitrogen for 20 minutes and then stoppered. The polymerization was run at 60°-70° C. for approximately 10 days. A film cast from the mother liquor was tacky, and elastic. The dried polymer was soluble in hexamethyl disiloxane and when cast from hexamethyl disiloxane produced a guick drying film.
EXAMPLE 32
To a reaction vessel was charged 70 g hexamethyl disiloxane, 16.5 g (0.039 mol) TRIS, 10.5 g (0.11 mol) methyl methacrylate, and 3.0 g (0.02 mol) isooctyl acrylate, and 0.026 g azobis (isobutyronitrile). The polymerization was run at 75°-81° C. under nitrogen for 18 hours. The reaction produced a very tacky polymer that was soluble in the mother liquor, hexamethyl disiloxane.
EXAMPLE 33
To a reaction vessel was charged 70 g hexamethyl disiloxane, 16.5 g (0.039 mol) TRIS, 12.75 g (0.13 mol) methyl methacrylate, and 0.75 g (0.004 mol) isooctyl acrylate, and 0.026 g azobis (isobutyronitrile). The polymerization was run at 74°-80° C. under nitrogen for 8 hours. The reaction produced a tacky polymer that was soluble in the mother liquor, hexamethyl disiloxane.
EXAMPLES 34-51
The polymers of Examples 34-51 were made by free radical polymerization in ethyl acetate solution at 25-30% monomer solids using VAZO 67 (a diazo free radical initiator commercially available from E.I. DuPont DeNemours & Co.) initiator and holding the reaction solution at 65° C. for 24 hours. Under these conditions, monomer conversion was greater than 95%. Polymer product was purified by precipitation in about five volumes of methanol to remove unreacted monomer and oligomer. The isolated solid was dried at 65° C. for 24 hours. The dried samples were characterized by inherent viscosity (IV) measured in ethyl acetate solution at 0.5 g/dl solids concentration and T g value determined by differential scanning calorimetry.
To prepare the test solution, the dried solid product was dissolved in 1% ethanol/99% HMDS to make a 10% solids solution. D4 was added at 3% of total solution and the solution was sterilized with 2.5 MRads. Tack was determined by comparing to a control sample A (IV 0.40, Tg 54° C.) of TRIS/MMA/I0A in monomer weight ratios of 55/35/10 which had been established as being too tacky for optimum use. Each test material was applied between fingers with a Q-tip, let dry 2 minutes and pressure was applied to hold two fingers together for 10 seconds. The amount of tackiness was determined to be less, the same or more than the control sample tested in the same way.
Durability was tested on all samples that showed less tack than the control and some samples which showed the same tack as the control. This test was run by applying a single coat of test solution on a forearm in approximately a 1"×1" patch with a Q-tip. A duplicate was run for each sample in order to compensate for location variability. Each sample was compared to control sample B (IV 0.44, Tg 46° C.), made by copolymerization of TRIS/MMA/EMA monomers in 55/22.5/22.5 weight ratios in a mixed solvent of 50/50 ethanol/HMDS and isolated by precipitation as described above. After 24 hours a solution of methylene blue in water was applied over the entire forearm. Dye would stain skin tissue where protective polymer was not present. Pinholes or cracks in the polymer also show up as blue since the dye can reach the underlying skin. A sample showing less blue stain than the control is considered more durable since the polymer must be present to protect the skin. The test is subjective, but fairly reproducible on a qualitative basis.
__________________________________________________________________________ COMPOSITION TACK DURABILITYEXAMPLE MONOMER RATIOS IV T.sub.g VS.A VS.B__________________________________________________________________________34 TRIS/MMA/IOA 0.40 54 -- --(CONTROL A) 50/35/1035 TRIS/MMA/EMA 0.44 46 -- --(CONTROL B) 55/22.5/22.5 TRIS/MMA/IOA36 57/38/5 0.37 67.7 SAME SAME37 57/37/6 0.37 60.7 LESS MORE38 56/36/8 0.38 59.3 SAME SAME39 55/39/6 0.38 64.8 LESS SAME40 55/38/7 0.37 64.0 LESS MORE41 55/37/8 0.38 59.4 SAME42 55/36/9 0.38 57.0 SAME43 54/39/7 0.38 62.9 LESS SAME44 54/38/8 0.33 61.6 SAME45 53/39/8 0.33 62.6 LESS MORE46 53/38/9 0.33 62.3 SAME47 53/37/10 0.33 55.4 SAME TRIS/MMA/EMA/IOA48 55/35/5/5 0.36 62.5 LESS LESS49 55/30/10/5 0.36 63.8 LESS MORE50 55/25/15/5 0.36 63.4 MORE51 55/20/20/5 0.36 55.2 MORE__________________________________________________________________________
EXAMPLES 52-59
Copolymers of 3-methacryloyloxypropyltris(trimethylsiloxy)silane (TRIS) and methyl metahcrylate (MMA) with cyclohexyl acrylate (CHA), lauryl methacrylate (LMA), isodecyl methacrylate (IDMA) and stearyl methacrylate (StMA) were prepared, characterized and tested for solubility in hexamethyldisiloxane. Monomer weight ratios for TRIS/MMA/third component respectively were either 55/40/5 or 55/30/15.
Examples 52-59 were prepared by polymerization at 30% reactive monomer in ethyl acetate solvent using azobisisobutyronitrile initiator at 0.2 weight percent based on monomer. Charges listed below were weighed into 4 ounce narrow mouth bottles and purged with nitrogen at 1 liter/min. flow bubbled into the liquid for one minute before closing. The initiator and solvent were added as a premix made by dissolving 0.086 g initiator per 100 g solvent. Reactions were run in a constant temperature bath (launderometer) at 65° C. for 24 hours.
The bottles were closed with a metal cap lined with a Teflon disk. Monomer conversion after 24 hours reaction was determined by measuring loss on drying at 105° C. for one hour and found to be 90% or higher for all samples. Solid polymer product was isolated by pouring a portion of the reaction solution into a large volume of methanol. The precipitated solid was collected and dried at 65° C. for at least 48 hours.
Solubility was determined by shaking the dried solid in a sufficient amount of hexamethyldisiloxane to afford a 10% solids solution. All of the eight samples were soluble. Sample 1 required 48 hours shaking for complete solution but the others dissolved within 12 hours.
Inherent viscosity and T g were measured on the dried polymer samples. Inherent viscosity was run in ethyl acetate solvent at nominal concentration of 0.5 g/dl. T g values were determined by differential scanning calorimetry. Results are tabulated below.
__________________________________________________________________________ INITIATOR/ SOLVENT PRE-SAMPLE TRIS MMA CHA LMA IDMA StMA MIX Tg IV__________________________________________________________________________52 11.55 g 8.4 g 1.05 g 49.0 g 74.4° C. 0.36853 11.55 6.3 3.15 49.0 58.9 0.37654 11.55 8.4 1.5 g 49.0 65.4 0.34655 11.55 6.3 3.15 49.0 35.5 0.32056 11.55 8.4 1.05 g 49.0 69.7 0.34857 11.55 6.3 3.15 49.0 47.3 0.32058 11.55 8.4 1.05 49.0 64.2 0.34359 11.55 6.3 3.15 49.0 30.4 0.319__________________________________________________________________________
The above examples are representative of specific embodiments of the present invention. However, many variations are possible. In all forms, the liquid polymer-containing coating material of this invention contains a siloxane-containing polymer and a solvent system comprising a major portion of a polydimethylsiloxane or mixture of such siloxanes and, if desired, a minor portion of a polar liquid or solvent or mixture thereof. In all cases the invention provides a method of forming a bandage on the body by applying a liquid polymer-containing bandage formulation or material to the body and volatilizing the solvent system to form a bandage, which is adherent to the body while providing good moisture transmission properties and protecting the skin or body surface of the user. | Combinations of alkyl siloxy siloxane-containing polymers admixed with liquid polydimethylsiloxanes are excellent non-stinging, non-irritating liquid coating material for forming films which act as conformable bandages adhering to and protecting nails, skin and mucous membrane wounds from abrasion, contamination, and desiccation, while stopping pain from exposed nerve ends and allowing body fluid evaporation. |
FIELD OF THE INVENTION
[0001] The present invention is directed generally to gas turbine systems, and more particularly to integrated gasification combined cycle gas turbine systems.
BACKGROUND OF THE INVENTION
[0002] The utilization of coal in the prior art has been minimized due to undesirable emissions, such as oxides of nitrogen and sulfur, particulate emissions and greenhouse gases such as carbon dioxide. As a result, there have been efforts to reduce these emissions and improve fuel efficiency of coal plants.
[0003] One of the systems that have been developed is the Integrated Gasification Combined Cycle (IGCC) system for use in power generation. IGCC systems were devised as a way to use coal as the source of fuel in a gas turbine plant. IGCC systems are clean and generally more efficient than prior art coal plants.
[0004] IGCC is a combination of two systems. The first system is coal gasification, which uses coal to create a clean-burning synthetic gas (“syngas”). The gasification portion of the IGCC plant produces syngas, which may then be used to fuel a combustion turbine. Coal is combined with oxygen in a gasifier to produce the syngas, hydrogen and carbon monoxide. The syngas may then be cleaned by a gas cleanup process. After cleaning, the syngas may be used in the combustion turbine to produce electricity.
[0005] The second system is a combined-cycle, or power cycle, which is an efficient method of producing electricity commercially. A combined cycle includes a combustion turbine/generator, a heat recovery steam generator (HRSG), and a steam turbine/generator. The exhaust heat from the combustion turbine may be recovered in the HRSG to produce steam. This steam then passes through a steam turbine to power another generator, which produces more electricity. A combined cycle is generally more efficient than conventional power generating systems because it re-uses waste heat to produce more electricity.
[0006] IGCC systems offer several advantages over current conventional coal-based power generation systems. One advantage is reduced emissions. Another aspect of IGCC plants is that emissions clean-up, including removal of sulfur and carbon dioxide, may be effected upstream of the combustor system in the fuel stream. Since this stream is far smaller than the entire flue gas stream, emissions removal equipment for an IGCC plant are lower than for a conventional coal plant of like output.
[0007] IGCC systems offer other advantages, such as higher efficiency, less coal used, higher turbine outputs, and/or the production of additional chemical by-products, such as hydrogen, which may be used as an alternative source of energy in other developing technologies.
[0008] Nevertheless, IGCC systems may still suffer from reduced efficiencies as compared to other systems. Since syngas has a lower heating value than other fuels, more syngas is needed to produce a selected turbine temperature. In addition, the product nitrogen stream from the Air Separation Unit (ASU) Island of an Integrated Gasification Combined Cycle (IGCC) plant may be at elevated temperatures, which might involve the use of equipment for reducing the heat.
[0009] Accordingly, it would be beneficial to provide a system that utilizes coal that has increased efficiencies as compared to prior art systems. It would also be beneficial to increase the integration of the components in the IGCC to increase efficiency and/or power out put of the IGCC systems.
SUMMARY OF THE INVENTION
[0010] This present invention provides a method of increasing the efficiency and/or power produced by an integrated gasification combined cycle system by increasing the integration between the air separation unit island, the heat recovery steam generator and the remainder of the system. By integrating heat available in the heat recovery steam generator in the remainder of the integrated gasification combined cycle system, heat may be utilized that may have otherwise been lost or used further downstream in the system. The integration helps to increase the efficiency of the combustion reaction and/or the gasification reaction used to produce the syngas utilized in the integrated gasification combined cycle system.
[0011] In particular, in one aspect, the present invention provides a method for increasing efficiency of an integrated gasification combined cycle system including the steps of producing a nitrogen gas product stream and an oxygen gas product stream using an air separation unit, feeding the oxygen gas product stream to a gasifier, producing a syngas stream in the gasifier using the oxygen gas product stream and coal, forming a fuel mixture stream using the syngas stream, and heating at least a portion of at least one of the oxygen gas product stream, nitrogen gas product stream, the fuel mixture stream, or both using heat from a heated regenerative steam generator.
[0012] In another aspect, the present invention provides a system for increasing efficiency of an integrated gasification combined cycle system including an air separation unit for producing a nitrogen gas product stream and an oxygen gas product stream, a gasifier for producing a syngas stream in the gasifier using the oxygen gas product stream and coal, a mixing valve for forming a fuel mixture stream using the syngas stream and at least a portion of the nitrogen gas product stream, and a heated regenerative steam generator for providing heat for heating at least one of the oxygen gas product stream, the nitrogen gas product stream, the fuel mixture stream, or both.
[0013] These and other embodiments are described in more detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Other objects, features and advantages of the present invention will become apparent upon reading the following detailed description, while referring to the attached drawings, in which:
[0015] FIG. 1 shows a schematic of a standard IGCC system.
[0016] FIG. 2 shows a schematic of an IGCC system according to one embodiment of the present invention.
[0017] FIG. 3 shows a schematic of an IGCC system according to another embodiment of the present invention.
[0018] FIG. 4 shows a schematic of an IGCC system according to yet another embodiment of the present invention.
[0019] FIG. 5 shows a schematic of an IGCC system according to still another embodiment of the present invention.
[0020] FIG. 6 shows a schematic of an IGCC system according to yet another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The present invention is more particularly described in the following description and examples that are intended to be illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. As used in the specification and in the claims, the singular form “a,” “an,” and “the” may include plural referents unless the context clearly dictates otherwise. Also, as used in the specification and in the claims, the term “comprising” may include the embodiments “consisting of” and “consisting essentially of.”
[0022] The present invention provides a method for increasing the efficiency of an integrated gasification combined cycle (IGCC) gas turbine system and an IGCC having increased efficiency. The present invention accomplishes the improved efficiency of the system by increasing the integration between the IGCC and the heat recovery steam generator (HRSG) and air separation unit (ASU) portions of the IGCC. In the present invention, heat from one area of the system is transferred and/or used in another area of the system to increase the overall efficiency of the system.
[0023] In one embodiment of the present invention, the improved systems and methods integrate heat from the HRSG either directly or through the use of one or more product gases from the ASU as part of a method for transferring heat in the IGCC system upstream. For example, in one embodiment, superheated steam from the HRSG may be used to heat the fuel mixture entering the combustor and/or heat the reaction products used in the gasifier. In these embodiments, the increased heat increases the efficiency of the respective processes. Alternatively, one or more product gases of the ASU may be heated by the HRSG and this heated product gas may then be used to heat the fuel mixture entering the combustor and/or heat the oxygen gas stream used in the gasifier. Since the excess heat is used upstream, the system operates at higher efficiencies than prior art systems since the amount of sygnas is increased and/or the efficiency of the turbine is increased, thereby increasing the amount of power produced.
[0024] In a standard IGCC system, with reference to FIG. 1 , the IGCC system includes an ASU 100 , which produces an oxygen gas product stream 105 and a nitrogen gas product stream 120 . The gasifier 110 produces a synthetic gas (“syngas”) product stream 115 , which may then be used as the fuel source for the combustor 130 . The ASU 100 , which may be a cryogenic ASU, is used to provide pure or substantially pure oxygen to the gasification reactor and, in alternative embodiments, may include a post-compression air bleed from the gas turbine 175 . The ASU 100 produces the oxygen gas product stream 105 and the nitrogen gas product stream 120 , which are generally below the temperatures of other streams in the IGCC system, such as the syngas stream 115 . As a result, in certain embodiments of the present invention, these streams may be used to transfer heat from the HRSG 155 to one or more other areas of the IGCC wherein the increased temperatures help to increase the efficiency of overall system.
[0025] Alternatively, or in addition thereto, heat from the HRSG 155 may be used to increase the temperature of the fuel mixture 140 entering the combustor 130 and/or the oxygen gas product stream 105 entering the gasifier. The HRSG 155 typically uses a feedwater stream 150 and heat from the gas turbine 175 to produce a superheated steam that is used to produce power using a steam turbine. By transferring some of this heat upstream, however, the methods of the present invention increase the overall efficiency of the system by using this heat further upstream, such as in the gasifier and/or the combustor.
[0026] A standard IGCC may also include an acid gas removal stage 165 since the syngas from the gasifier is generally cleaned before it is used as a gas turbine fuel. The cleanup process typically involves removing sulfur compounds, ammonia, metals, alkalytes, ash, and/or particulates to meet the gas turbine's fuel gas specifications. The syngas may then be heated in a syngas heater 170 before being used in the combustor 130 . In addition, the nitrogen gas product stream 120 , if used to dilute the fuel mixture 140 , may first be passed through a heat exchanger 125 which is used to heat the nitrogen stream 120 since the product streams from the ASU 100 are typically at cooler temperatures because most air separation process are performed at sub-zero temperatures.
[0027] Accordingly, by using heat from the HRSG and/or one or more product streams from the ASU, the present invention increases the overall efficiency of the IGCC system by increasing the amount of syngas created and/or by increasing the temperature of the fuel mixture. These concepts may be accomplished using a variety of embodiments.
[0028] In one embodiment, product nitrogen (N 2 ) generated from the ASU is routed to the HRSG where it is heated by the gas turbine exhaust gas. After leaving this heat exchanger, the heated nitrogen-gas product stream may be routed to another heat exchanger where it transfers heat to the syngas fuel. Upon leaving the heat exchanger, the nitrogen is then returned to the HRSG and heated in yet another heat exchanger. Upon exiting this heat exchanger, it is mixed with the fuel stream and then enters the combustor of the gas turbine.
[0029] FIG. 2 provides a schematic of this embodiment. As shown, the ASU 200 includes an oxygen gas product stream 205 that may be sent to the gasifier 210 for use in forming the syngas product stream 215 . The nitrogen product gas stream 220 from the ASU 200 may then be passed through a heat exchanger 225 to heat the nitrogen gas 220 . Instead of then being mixed with the syngas just prior to being fed into the combustor 230 , this embodiment diverts all or a part of the nitrogen gas stream 220 to a first nitrogen heater 235 , which is located in the HRSG 255 , wherein heat from the turbine 275 may be transferred to the nitrogen gas 220 . The heated nitrogen flow may then be passed through a heat exchanger 280 to increase the temperature of the fuel mixture 240 entering the combustor 230 . The nitrogen gas stream 220 may then be sent to a second nitrogen heater 285 within the HRSG 255 and then mixed with the heated syngas, such as with a mixing valve, to form the fuel mixture 240 that then enters the combustor 230 . This embodiment may also include a syngas cooler 245 , which uses feedwater 250 from the HRSG 255 to form steam 260 that may be used to generate power in the HRSG; an acid gas removal stage 265 ; and a syngas heater 270 . Combustion products from the combustor 230 may be sent to gas turbine 275 to produce power, and since the temperature of the fuel mixture 240 is higher, the temperature of the combustion products is higher, thereby producing more power in the turbine.
[0030] FIG. 2 shows all of the ASU product nitrogen gas being routed through the heat exchanger system; however, it is also possible that only a fraction of the product nitrogen may be routed in this manner. In addition, in FIG. 2 , the heat exchanger 280 is depicted as downstream of the nitrogen fuel mixing point 282 ; however, this heat exchanger could also be upstream of the mixing point.
[0031] In an alternative embodiment, product nitrogen (N 2 ) gas generated from the ASU is routed to the HRSG where it is heated by the gas turbine exhaust gas. After leaving this heat exchanger, the heated nitrogen is mixed with the fuel stream and then enters the combustor of the gas turbine.
[0032] FIG. 3 provides a schematic of this embodiment. As shown, the ASU 300 includes an oxygen gas product stream 305 that may be sent to the gasifier 310 for use in forming the syngas product stream 315 . The nitrogen product gas stream 320 from the ASU 300 may then be passed through a heat exchanger 325 to heat the nitrogen gas 320 . Instead of then being mixed with the syngas just prior to being fed into the combustor 330 , this embodiment diverts all or a part of the nitrogen gas stream 320 to be heated by the HRSG 355 using a nitrogen heat exchanger 335 . The heated nitrogen stream may then be mixed with the syngas stream 315 , such as through the use of a mixing valve, to form a fuel mixture 340 prior to being combusted in the combustor 330 . This embodiment may also include a syngas cooler 345 , which uses feedwater 350 from the HRSG 355 to form steam 360 that may be used to generate power in the HRSG; an acid gas removal stage 365 ; and a syngas heater 370 . Combustion products from the combustor 330 may be sent to gas turbine 375 to produce power. In addition, FIG. 3 shows all of the ASU nitrogen product gas 320 being routed through the heat exchanger 335 ; however, it is also possible that only a fraction of the product nitrogen could be routed in this manner.
[0033] In yet another alternative embodiment, product nitrogen generated from the ASU is routed to the HRSG where it is heated by the gas turbine exhaust gas. After leaving this heat exchanger, the heated nitrogen gas may be routed to an oxygen heat exchanger wherein heat is transferred to the ASU product oxygen stream prior to being used in the gasifier. The nitrogen stream may then be routed back to the HRSG where it is reheated before mixing with the fuel stream that enters the combustor of the gas turbine.
[0034] FIG. 4 provides a schematic of this embodiment. As shown, the ASU 400 includes an oxygen gas product stream 405 that may be sent to the gasifier 410 for use in forming the syngas product stream 415 . The nitrogen product gas stream 420 from the ASU 400 may then be passed through a heat exchanger 425 to heat the nitrogen gas 420 . Instead of then being mixed with the syngas just prior to being fed into the combustor 430 , this embodiment diverts all or a part of the nitrogen gas stream 420 to a first nitrogen heater 435 , which is located in the HRSG 455 , wherein heat from the turbine 475 may be transferred to the nitrogen gas 420 . The heated nitrogen gas can then be passed through an oxygen gas heat exchanger 490 to increase the temperature of oxygen gas stream 405 entering the gasifier 410 . The nitrogen gas stream 420 may then be sent to a second nitrogen heater 485 within the HRSG 455 and then mixed with the heated syngas to form the fuel mixture 440 that then enters the combustor 430 . This embodiment may include a syngas cooler 445 , which uses feedwater 450 from the HRSG 455 to form steam 460 that may be used to generate power in the HRSG 455 ; an acid gas removal stage 465 ; and a syngas heater 470 . Combustion products from the combustor 430 may be sent to gas turbine 475 to produce power, and since the temperature of the fuel mixture 440 is higher, the temperature of the combustion products is higher, thereby producing more power in the turbine. And, since the temperature of the oxygen gas stream 405 is higher, greater amounts of syngas 415 may be generated in the gasifier 410 .
[0035] In still another embodiment, instead of using a product gas from the ASU, heat, in the form of steam, may be transferred upstream, such as through the use of steam. In one embodiment, flue gas energy may be used to generate high pressure superheated steam in the HRSG. This steam is routed to a heat exchanger where it transfers heat to one or more of the syngas, the diluent nitrogen, and/or the mixed fuel stream. The steam may then be sent from the heat exchangers and returned to the HRSG to be reheated.
[0036] FIG. 5 provides a schematic of this embodiment. As shown, the ASU 500 includes an oxygen gas product stream 505 that may be sent to the gasifier 510 for use in forming the syngas product stream 515 . The nitrogen product gas stream 520 from the ASU 500 may be passed through a heat exchanger 525 to heat the nitrogen gas 520 . A superheated steam stream 592 , which is formed using heat from the HRSG 555 , may be used to heat one or more of the syngas (using heat exchanger 594 ), the diluent nitrogen (using heat exchanger 596 ), and/or the mixed fuel stream (using heat exchanger 598 ). In these embodiments, the resulting heated fuel mixture 540 then enters the combustor 530 . Combustion products from the combustor 530 can be sent to the turbine 575 to produce power.
[0037] Alternatively, a combination of these heat exchangers, with the steam flowing either in parallel, as shown, or in series, that is, the steam leaving one heat exchanger enters another heat exchanger, may be used in alternative embodiments. In addition, FIG. 5 shows the steam leaving the heat exchanger returning to the HRSG; however, it may be routed to the gasifier as a feedstock, to a water-gas shift reactor or syngas saturator as a feed stock, to the steam turbine as a working fluid, or elsewhere in the IGCC plant. Lastly, the HRSG steam shown in FIG. 5 may be a High Pressure (HP) steam; however, it is possible that steam of a lower pressure could be used for this heating application. The use of lower pressure steam for gas turbine fuel heating could conceivably provide the steam turbine with steam at a better suited pressure level, and would result in lower cost heat exchangers due to the lower maximum allowable working pressures present.
[0038] In yet another embodiment, superheated steam generated in either the syngas cooler or HRSG heat exchangers, or a combination of both, is routed to an oxygen heat exchanger where heat is transferred to the ASU product oxygen stream prior to being used in the gasifier. The liquid stream, whether in form of saturated steam or condensed as water, may then be routed back to the HRSG.
[0039] FIG. 6 provides a schematic of one aspect of this embodiment. As shown, the ASU 600 includes an oxygen gas product stream 605 that may be sent to the gasifier 610 for use in forming the syngas product stream 615 . The nitrogen product gas stream 620 from the ASU 600 may be passed through a heat exchanger 625 to heat the nitrogen gas 620 . The heated nitrogen stream can be combined with the fuel 615 to form a fuel mixture 640 that is fed to the combustor 630 . A superheated steam stream 692 , which is formed using heat from the HRSG 655 , may be passed through an oxygen gas heat exchanger 690 to increase the temperature of oxygen gas stream 605 entering the gasifier 610 . As previously discussed, by increasing the temperature of the oxygen, the efficiency of the gasifier 610 is increased, thereby increasing the amount of syngas generated per unit of coal used as feedstock. This embodiment may include a syngas cooler 645 , which uses feedwater 650 from the HRSG 655 to form steam 660 that may be used to generate power in the HRSG; an acid gas removal stage 665 ; and a syngas heater 670 . However, it is to be understood that the stream 660 may be used in lieu of steam stream 692 or in addition thereto. Combustion products from the combustor 630 can be directed to the turbine 675 to produce power.
[0040] The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention. | A system and method for increasing the efficiency and/or power produced by an integrated gasification combined cycle system by increasing the integration between the air separation unit island, the heat recovery steam generator and the remainder of the system. By integrating heat produced by the heat recovery steam generator in the remainder of the integrated gasification combined cycle system, heat may be utilized that may have otherwise been lost or used further downstream in the system. The integration helps to increase the efficiency of the combustion reaction and/or the gasification reaction used to produce the syngas utilized in the integrated gasification combined cycle system. |
RELATED APPLICATIONS
This application is a continuation of copending application Ser. No. 09/427,281, filed Oct. 26, 1999 now U.S. Pat. No. 6,493,939, which is a continuation of application Ser. No. 09/172,803, filed Oct. 14, 1998, now U.S. Pat. No. 5,971,618, which is a continuation of application Ser. No. 08/655,040, filed May 26, 1996, now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates generally to assembly lines and conveyor systems, and, in particular, to a flange bearing for supporting a rotatable shaft.
In manufacturing, assembly lines and conveyor systems commonly utilize flange bearings to support cylindrical shafts upon which manufactured products are transported. The bearings are mounted to a support structure which forms a track or bed along which the products are conveyed. Each shaft is received in a bearing insert of a housing for the flange bearing. The flange bearing might comprise a square housing mounted using four bolts, one at each corner. Alternatively, the flange bearing might comprise an eye-shaped housing utilizing two bolts for mounting.
Cast iron was the common material used for manufacturing early flange bearing housings which were mounted by either two or four bolts. A solid body was formed which easily withstood the stresses imparted by the heavy and/or cyclic loads from the shaft supported therein. Further, the cast iron housing was usually either metal-plated or painted to resist corrosion from exposure to water, cleaning chemicals, spilled products or other contaminates, especially in the food processing industry. However, the housing exterior would eventually deteriorate or become unsightly, especially since stringent cleaning was required to meet sanitation specifications in the aforementioned industry.
A more recent type of flange bearing comprises an injection-molded plastic housing. In particular, if the housing is injection molded in the form of solid plastic, the housing would disadvantageously shrink and deform unpredictably upon cooling. In order to provide an injection-molded housing of the equivalent strength of cast iron with repeatable dimensional stability, it is necessary to increase the overall geometry slightly for strength and incorporate a ribbed structure for dimensional stability. the result is an “engineered plastic” housing providing the desired positional geometry incorporating ribs and cavities. In an engineered plastic housing, the ribs provide strengthening to resist stress fractures of the housing from the shaft loading, while maintaining the desired shape during the molding process.
In addition, the cavities of the engineered plastic housing are more difficult and time consuming to clean satisfactorily than a solid body housing. Plugs created to fill the cavities, thereby making cleaning easier, tend to settle after time and during temperature changes so that the outer surface of the housing body is no longer flush, and the same cleaning difficulties remain. Plugs are often made of a different material than the housing and consequently expand and contract at a different rate than the housing causing undesirable cracks, crevices and uneven surfaces.
In view of the foregoing, a need exists for an improved bearing housing that overcomes the problems mentioned.
SUMMARY OF THE INVENTION
The present invention overcomes the aforenoted disadvantages by providing a housing having a lightweight, substantially solid body including an encased reinforcing member. This member provides additional strength and aids in transmitting loads from a shaft supported by the housing radially outwardly to fasteners which are used to mount the housing. The body does not have recesses formed on its mounting surface which could harbor contaminates, and therefore thorough cleaning of the housing is made easy.
The reinforcing member is preferably a loop formed from a band of metal which surrounds the bolt holes and shaft opening of the housing. Ends of the metallic band may be fastened using a screw engaged through holes on the band ends. Alternatively, the band ends may be spot-welded together, or the band may be formed in a continuous loop. In another embodiment, the reinforcing member may comprise one or more substantially straight metallic strips encased within the body material.
An important feature of the present invention is the use of the reinforcing member to provide additional strength to a lightweight body. Stress fractures from heavy and/or cyclic loading from a shaft supported by the housing are less likely to occur as a result of the presence of the reinforcing member in the body. The member may be suspended within the housing material and helps provide transmission of the loading radially outwardly from the shaft to the fasteners.
Another important feature of the present invention is the formation of a substantially solid body which does not include recesses or cavities for the accumulation of dirt, grease or other contaminates. Thus, cleaning the housing to meet sanitation specifications is readily accomplished.
In one preferred embodiment, the housing comprises a generally parallelogram shaped flange bearing. Two bolts in holes in narrow portions of a housing body mount the bearing to a conveyor structure. A rotatable shaft is supported in a bearing insert received in an opening in the housing body. A cover is optionally placed over one end of the shaft to protect passersby and to warn of the moving part contained therein. Alternatively, the housing may comprise a substantially square flange bearing having four bolts for mounting.
A preferred method of manufacturing a reinforced housing of the present invention comprises the steps of:
a) preparing a mold for the housing including desired openings for receiving one or more fasteners and a shaft;
b) preparing a metallic band for insertion into a space of the mold, with the band forming a shape smaller than the mold's outer shape;
c) suspending the band within the mold;
d) pouring a thermosetting material into the mold to encase the band; and
e) cooling the material thereby creating a substantially solid yet lightweight body reinforced by the band contained within. In this method, Step b) may comprise using a screw engaged through holes in the ends of the band which is shaped into a loop. Alternatively, Steps b) and c) may comprise suspending one or more substantially straight metallic strips in the space of the mold as the reinforcing members, instead of a loop.
Further advantages and applications will become apparent to those skilled in the art from the following detailed description and the drawings referenced herein.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front perspective view of a preferred flange bearing embodiment having a housing constructed in accordance with the present invention;
FIG. 2 is a top plan view of the housing of FIG. 1, with a reinforcing member shown in phantom;
FIG. 3 a is a top plan view of the reinforcing member;
FIG. 3 b is a top plan view of the reinforcing member comprising multiple strips;
FIG. 4 is a side elevational view of the reinforcing member;
FIG. 5 is a detail view of overlapped ends of the reinforcing member having holes;
FIG. 6 is an alternative cross-sectional view of the reinforcing member taken along line 6 — 6 in FIG. 3 a;
FIG. 7 a is a top plan view of a bolt sleeve for the housing of FIG. 1;
FIG. 7 b is a side elevational view of the bolt sleeve;
FIG. 8 is a perspective view of an alternate embodiment of the present invention; and
FIG. 9 is a top plan view of the embodiment of FIG. 8 with a reinforcing member shown in phantom.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Most modern manufacturing facilities rely heavily upon conveyor systems which transport products through the various manufacturing procedures along a predetermined path. The manufacturing environment includes exposure of manufacturing and conveyor equipment to various fluids, dust, material debris and other contaminates. The fluids may include lubricants and/or liquid products. The material debris may be metal, plastic or food particles. Dirt or even bacteria may be present in the manufacturing facility and must be satisfactorily removed for product quality assurance, particularly in the food processing industry which maintains high sanitation standards.
A preferred embodiment comprising a two bolt flange bearing 10 constructed in accordance with the present invention is shown in FIG. 1 and is used in conveyor systems to support a shaft (not shown) as will be readily understood by those of skill in the art. The shaft is preferably supported within a bearing insert 12 positioned in a housing 14 between holes 16 for mounting of the bearing 10 to a conveyor structure (not shown). The bearing insert 12 is typically a lubricated ball bearing. The shaft diameters may range from about ¾ inches to about 3 inches. Mounting bolts (not shown) received in the holes 16 of bolt sleeves 18 are generally about {fraction (5/16)} inches to about ¾ inches in diameter.
A substantially flat or planar mounting surface 20 of the bearing 10 may be formed on a distal side of the housing 14 , and a non-planar surface 22 may be formed on a proximal side of a substantially solid body 24 of the housing 14 . The mounting surface 20 generally forms an eye shape or parallelogram having rounded corners, with the bolt sleeves 18 and mounting holes 16 positioned within acute corners and an opening 26 for the bearing insert 12 positioned within obtuse corners of the parallelogram. A screw and grease inlet orifice 28 are preferably provided at a side wall 30 of the housing 14 for lubrication of the bearing as required. Although a two bolt flange bearing is shown and described herein, it is understood that a four bolt and other flange bearing designs are possible in the present invention.
For protection against contaminates contributing to bearing failure, covers and seals (not shown) may optionally be placed at the bearing insert 12 , over the end of the shaft as will be understood by those of skill in the art. Brightly colored covers also provide visual warning that a moving part is contained within. These seals may include a back shaft seal positioned between the distal surface 20 of the housing 14 and the mounting wall of the conveyor structure, as well as an O-ring and front shaft seal positioned between the open or closed cover and a proximal surface 31 of the housing 14 .
FIG. 2 shows the housing 14 with a reinforcing member 32 illustrated in phantom. The member 32 is preferably encased within the material of the body 24 in the present invention and preferably comprises a loop formed by a metallic strip or band. The material of the housing body 24 is preferably urethane, although other pourable, thermosetting materials may alternatively be used to form the housing body 24 . In the preferred embodiment, the urethane is poured or pumped into a female cavity within which is suspended the reinforcing member 32 .
The housing 14 for the two bolt flange bearing 10 is preferably of standard dimensions, and for supporting a shaft of either 1{fraction (3/16)} or 1¼ inches in diameter the housing 14 measures approximately 5.56 inches at the widest part and 3.31 inches perpendicular to the widest part. The distance between centers of the holes 16 is about 4.59 inches, and the bearing insert opening 26 is about 2.44 inches in diameter. The distance between the mounting and proximal surfaces 20 , 22 of the housing 14 is about 0.89 inches.
The loop of the metallic band 32 generally conforms to a parallelogram shape, as shown in FIG. 3, and is somewhat smaller than the shape of the bearing's mounting surface 20 . The metallic band 32 is preferably positioned to circumscribe the mounting holes 16 and bearing insert opening 26 . The loop 32 preferably measures about 5.21 inches at its widest part and about 2.86 inches measured perpendicular to the widest part. The radius of curvature at about the bearing insert position is about 1.40 inches, and the radius of curvature at about the mounting holes 16 is about 0.279 inches. The reinforcing member 32 is preferably 300 series stainless steel, 16 or 20 gage.
The metallic band 32 may be formed as a continuous loop, or the loop may be created by fastening together ends 34 of the band 32 . FIGS. 4 and 5 show side views of the band 32 , with the latter showing holes 36 provided near the band ends 34 for receiving a fastener. In this embodiment, an overlap of about one inch is provided at the band ends 34 and a screw (not shown) is received through the holes 36 of each end 34 while the band 32 is suspended within the housing mold and the poured urethane cools and sets during the manufacturing of the housing 14 . Alternatively, the ends 34 of the band 32 may be welded together as will be easily understood by those of skill in the art.
In another preferred embodiment, the metallic band 32 includes a longitudinal central portion 38 having an arcuate cross-section, shown in FIG. 6 . The curvature is such that an inner surface 40 of the central portion 38 , toward the bearing insert 12 , is concave, and an outer surface 42 , toward the side walls 30 of the housing 14 , is convex. The band 32 has a total width of about ⅝ inches, and the central portion 38 has a radius of curvature of approximately 0.13 inches such that the band 32 measures about {fraction (3/16)} inches from an innermost point to an outermost point of the central portion 38 of the band 32 .
The load capacity of the two bolt flange bearing housing 14 is preferably up to about 1,710 lbs. The housing load capacity for a four bolt flange bearing constructed in accordance with the present invention is preferably up to about 3,640 lbs. The central portion 38 is preferably curved as described (FIG. 6) to assist the transmission of the loads radially outward from the shaft to the mounting bolts. However, flat bands not having a curved central portion 38 , as shown in FIGS. 2-4, may alternatively be used without loss of the advantages of the present invention. Further, in alternate embodiments, one or more substantially straight metallic bars or strips may be used as reinforcing members for the housing body. The strip(s) are preferably positioned along the longest portion(s) of the housing body 24 . Thus, the reinforcing member 32 of the present invention is not limited to a loop shape but may comprise element(s) not conforming to the general outer shape of the housing body 24 .
FIGS. 7 a and 7 b show the sleeve 18 which is received in the housing 14 and forms the hole 16 for the mounting bolt (not shown). The sleeve 18 is substantially cylindrical and may have an exterior grooved portion 44 . The outer diameter at ends 46 of the sleeve 18 is about 0.63 inches, and the outer diameter at the grooved portion 44 is about 0.56 inches. The inner diameter of the sleeve 18 is about 0.44 inches and the sleeve length is about 0.75 inches.
Referring to FIG. 8, levelers are used for various machinery and have problems similar to those mentioned above for the flange bearing 10 . Levelers are used on the bottom ends of the legs of a machine to adjust or level the machine height. However, adequate cleaning and disinfecting is greatly complicated by the presence of recesses, cavities, apertures and the like in the leveler housing.
In another embodiment of the present invention, FIG. 8 shows a leveler 50 comprising a somewhat teardrop shaped foot or housing 52 for supporting a machine (not shown) at an adjustable height. A threaded steel stem or shaft 54 is preferably received in an opening 56 in a broad portion 58 of a housing body 59 , and a narrow portion 60 of the body 59 preferably has a hole 62 to receive a bolt (not shown) for mounting the foot 52 to the floor or other surface. The hole 62 is preferably offset a distance away from the shaft opening 56 in order to accommodate a drill or other tool used for securing the bolt to the floor. The shaft 54 is received in a leg of the machine, and the machine height is adjusted by rotation of the shaft 54 .
The top plan view of FIG. 9 shows the teardrop shaped housing 52 having a reinforcing member 64 in phantom. It is understood, however, by those skilled in the art that other shapes for the leveler housing 52 are available and may be used in the present invention. The reinforcing member 64 preferably comprises a metallic band forming a loop which generally conforms to the outer shape of the housing 52 . The use of the reinforcing member 64 adds strength to resist upward pulling loads applied to the housing 52 which preferably has a smooth underside without cavities (not shown).
The housing 52 preferably measures about 5.5 inches at the, widest part, and a distance of about 2.75 inches separates the lag hole 62 for receiving the bolt and the shaft opening. The narrow portion 60 of the housing 52 is about 0.73 inches thick, and the broad portion 58 of the housing 52 is about 1.10 inches thick.
The shaft 54 is preferably about 7.25 inches long and may have a diameter of about ¾ inches to about 1¼ inches. The shaft 54 may optionally be zinc-plated. Wrench flats (not shown) are typically provided at about 1¼ inches from the distal end of the shaft 54 which is received in the housing opening 56 , to facilitate the leveler height adjustment by rotating the shaft 54 at the flats.
The metallic band 64 preferably forms a loop having a maximum diameter of at least 3⅝ inches. The band 64 preferably has a width no greater than about 0.7 inches. The band 64 may be flat or have a curved central portion as described herein. The band 64 may comprise fastened loop ends or be continuously formed. Alternatively, the reinforcing member 64 may comprise one or a plurality of substantially straight metallic strips for assisting the load transmission from the shaft 54 to the bolt. The member 64 is preferably suspended within a poured urethane material. Preferably, the load capacity of the leveler housing 52 is up to about 7,200 lbs.
A preferred method of manufacturing a housing 14 , 52 constructed in accordance with the present invention comprises the steps of:
a) preparing a mold for the housing 14 , 52 including desired openings for receiving one or more fasteners and a shaft 54 ;
b) preparing a metallic band 32 , 64 for insertion into a space in the mold, the band 32 , 64 forming a shape smaller than the mold's cavity;
c) suspending the band 32 , 64 within the mold;
d) introducing a thermosetting material into the mold to encase the band 32 , 64 ; and
e) cooling the material thereby creating a substantially solid yet lightweight body 24 , 59 reinforced by the band 32 , 64 contained within. In this method, Step b) preferably comprises using a screw engaged through holes 36 in ends 34 of the band 32 , 64 to secure the band 32 , 64 in a loop shape. Although, other methods of securing the band ends 34 may also be used as known to those of ordinary skill in the art. Steps b) and c) may alternatively comprise suspending one or more substantially straight metallic strips in the mold as the reinforcing members, instead of a loop. As will be readily understood by those of skill in the art, Step d) may be accomplished by a variety of methods including, but not limited to, pouring or pumping the thermosetting material into the mold.
The embodiments illustrated and described above are provided merely as examples of the present invention. Other changes and modifications can be made from the embodiments presented herein by those skilled in the art without departure from the spirit and scope of the invention, as defined by the appended claims. | A flange bearing comprises a housing having a body with a reinforcing member encased therein. The housing provides strength and resistance to stress fracturing without the use of heavy materials, such as cast iron, or the use of ribs and recesses which can harbor contaminates. The bearing is preferably lightweight and easily cleaned. Also, a leveler constructed in accordance with the present invention provides similar advantages. |
BACKGROUND OF THE INVENTION
The present invention relates generally to a flail mower attachment for skid steer vehicles. In particular, the present invention is a hydraulically powered flail mower that may be readily attached to the front of the skid loader vehicle and detached therefrom as desired.
Skid steer vehicles are compact, highly maneuverable vehicles which are maneuvered by an operator seated within an operator compartment by actuating a pair of steering levers, typically positioned to the left and right sides of the operator. The left lever controls the rotation of the pair of wheels on the left side of the skid loader vehicle and the right lever controls the rotation of the pair of wheels on the right side of the skid loader vehicle. The extent to which each lever is pushed in the forward direction controls the forward speed at which the wheels on that side of the vehicle rotates. Similarly, the extent to which the lever is pulled in a reverse direction controls the speed at which the wheels on that side of the vehicle are rotated in a reverse direction. When a lever is in the centered neutral position, the wheels on the associated side do not rotate. The levers are typically biased to the neutral position.
Steering is accomplished by the differential speeds of the two wheels on one side of the vehicle as compared to the two wheels on the other side of the vehicle. Typically, two of the wheels are rotating and two are skidding or rotating in the opposite direction in order to effect a vehicle turn around the skidding wheels or reversing wheels. This type of steering substantially digs up the soil on which the skid steer vehicle is operating. The use of skid steer vehicles is usually limited to areas in which such disturbance of the soil is not a concern, such as roadbeds and construction sites. Use of skid steer vehicles on lawns and other decorative turf is generally avoided.
Attachments such as an auger, a grapple, sweeper, landscape rake, snowblower or backhoe, some of which may include their own hydraulic motor, are sometimes mounted to a boom assembly on the front of the skid steer loader. An auxiliary hydraulic system is used to control the flow of hydraulic fluid between the skid steer vehicle auxiliary hydraulic pump and the hydraulic motor on the front mounted attachment and is used to actuate hydraulic cylinders that position the front mounted attachments. Attachments such as scarifiers or stabilizers are sometimes mounted to the rear of the loader and may be positioned by the use of hydraulic cylinders actuated by means of the auxiliary hydraulic system.
A rotary mower has been shown adapted for use with a skid steer vehicle as described in U.S. Pat. No. 5,435,117. This type of adaption has not been fully satisfactory. In order to get a 60 inch cut, which is seen to be the minimal cut that is considered desirable, the dimension of the mower housing must be at least 72 inches in width and length. As depicted in FIG. 2 of the '117 patent, the great length of the rotary mower housing projects a great distance in front of the skid steer vehicle. Such rotary mowers weigh as much as fifteen hundred pounds. Such weight greatly destabilizes the very short wheelbase skid steer vehicle when the rotary mower is raised, as depicted in FIG. 2 of the '117 patent.
Additionally, rotary mowers are known to present serious missile hazards to personnel as a result of the very high tip speeds and the substantial mass of the rotating blades. Rocks and other debris will carry substantial distances at high velocity, propelled by a blade tip, thus necessitating an automatic cutoff as disclosed in the '117 patent. Even with a cutoff, the inertia of the rotating blades will cause them to continue to rotate at relatively high rotational speeds for as much as a minute, even after the flow of hydraulic fluid is cut off, unless the blades are actively braked. The blades continue to pose a hazard even after hydraulic flow cutoff.
There is a need to mow vegetation in an overgrown area where construction is going to be performed prior to commencement of the construction operations. In the past, special mowers and tractors were brought in to the site to mow the vegetation prior to commencement of the construction operations. This entails the expense and inconvenience of bringing in special equipment to perform a single preparatory mowing operation. If, during the construction operations, a second mowing was needed, the special equipment would have to be returned. Skid steer vehicles typically remain at the construction site to perform a variety of tasks using different attachments for the duration of construction operations.
It would be a decided advantage in the industry if the additional operation and expense in site preparation associated with bringing in special mowing equipment could be avoided. The mowing that is performed at the site should be the safest operation possible. Additionally, the mower should be readily available at the site to perform subsequent mowing operations as needed after the initial mowing operations.
SUMMARY OF THE INVENTION
The flail mower attachment of the present invention substantially meets the aforementioned needs. A skid steer vehicle that is already at the construction site to perform other excavation operations utilizing attachments such as the aforementioned attachments can do the mowing site preparation work with the flail mower attachment of the present invention. This avoids the need to truck in special mowers to do the mowing preparation. Such preparation does not require the care that is necessary in mowing lawns and other decorative turf, so that the damage to the soil done by the skid type steering of the skid steer vehicle is not a factor, making the flail mower attachment of the present invention very useful and cost effective.
Additionally, a flail mower is inherently safer from a missile hazards standpoint than a rotary mower. The tip speeds of the cutting hammers of the flail mower are greatly reduced as compared to the tip speeds of the rotary blades. Further, the mass of the individual hammers is only a small fraction of the mass of the rotary blades, making it much less likely that the hammer is able to impart a substantial velocity to a rock or other debris. Further, the blades of the rotary mower operate in a plane that is parallel to the surface of the ground, which tends to eject rocks out from under the mower housing, parallel to the ground in all directions. The hammers of the flail mower operate in a plane that is transverse to the surface of the ground. Any rocks picked up by the flail mower will be thrown to the rear of the flail mower and under the skid steer vehicle, presenting a substantially reduced missile hazard as compared to the rotary mower.
The flail mower is a much more compact unit than is the rotary mower. While the flail mower has a weight that is comparable to the rotary mower, the compactness of design results in a substantially reduced destabilizing effect on the skid steer vehicle when the flail mower is raised.
An improved skid steer vehicle in accordance with the present invention has a longitudinally extending main frame and wheels for supporting the main frame for movement over the ground. An operator's compartment spans substantially the entire lateral distance of the main frame in the fore and aft midportions thereof. An engine is contained within an engine compartment disposed rearward of the operator's compartment and includes an auxiliary hydraulic power supply driven off the engine. A pair of spaced apart actuating arms are operably coupled to the rear of the frame and have a quick attaching mount. The improvement comprises a flail mower implement that has a quick attachment receiver that is adapted for selective engagement with the quick attaching mount of the pair of actuating arms.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of a flail mower of the present invention positioned in front of a skid steer vehicle with portions of the flail apparatus depicted in phantom;
FIG. 2 is a top elevational view of the flail mower attached to the front portion of the skid steer vehicle;
FIG. 3 is a side elevational view of the flail mower with portions of the flail apparatus depicted in phantom attached to the front portion of the skid steer vehicle; and
FIG. 4 is a rear perspective view of the flail mower and the quick attachment receiver thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A skid steer vehicle 10, which includes a flail mower attachment 50 in accordance with the present invention, is illustrated generally in FIG. 1, the flail mower attachment 50 being depicted separated from the skid steer vehicle 10 in a disposition that is typical of the disposition just prior to attaching the flail mower 50 to the skid steer vehicle 10. The skid steer vehicle 10 includes a main frame assembly 16 mounted to a lower frame assembly or transmission case (not shown), lift arm assembly 30 and operator's compartment 40. An engine compartment 22 is located at the rear of the vehicle 10. Wheels 12 are mounted to stub axles 14 and extend from both sides of the main frame assembly 16. Main frame assembly 16 defines longitudinal direction 24, transverse direction 26, and elevational direction 28, as shown in FIGS. 1-2. Additional, main frame assembly 16 defines a central axis 29 (FIG. 2).
The lift arm assembly 30 is mounted to upright members 20 which are located at the rear of the main frame assembly 16. Alternative designs of skid steer vehicles 10 do not have the prominent upright members 20, as depicted, and attach the lift arm assembly 30 to the rear of the main frame assembly 16. As shown, the lift arm assembly 30 includes a pair of lift arms 32, preferably equally spaced from central axis 29, and a front quick attachment mount 35 that is pivotally mounted to the lift arms 32. Front mounted attachments or implements, such as the flail mower 50, are mounted to the lift arm assembly 30 by means of the quick attachment mount 35. The lift arm assembly 30 is raised and lowered with respect to the main frame assembly 16 by a pair of lift cylinders 36. The attachment mount 35, and therefore the flail mower 50, are rotated with respect to lift arms 32 by tilt cylinder 37, depicted in FIGS. 2 and 4. The function of the tilt cylinder 37 may also be performed by a pair of spaced apart tilt cylinders in some skid steer vehicle 10 designs.
The operator's compartment 40 takes up substantially all of the space between the rails of the main frame assembly 16 in the mid and forward portions of the vehicle 10 and is partially enclosed by cab 42. Cab 42 is an integral unit of the vehicle 10. In some skid steer vehicles 10, the cab 42 is pivotally mounted to main frame 16. Cab 42, including the operator seat (not shown), can thereby be rotated to permit access to the rear mounted engine disposed in the engine compartment 22, the transmission case, and other mechanical and hydraulic systems disposed therein. The cab 42 may also be selectively slidable within the main frame 16 to expose the mechanical and hydraulic systems of the skid steer vehicle 10.
All operations of vehicle 10 can be controlled by an operator from within the operator's compartment 40. The hydraulic drive system of vehicle 10 includes a pair of steering levers (not shown), which are pivotally mounted on the left and right sides, respectively, of the operator's compartment 40. The levers can be independently moved in forward and rearward directions, and are biased to a central or neutral position. Actuation of the levers causes the wheels 12 on the respective side of the vehicle 10 to rotate at a speed and in a direction corresponding to the extent and direction of the controlling lever motion. The lift cylinders 36 and tilt cylinder 37 are independently actuated through movement of separate foot pedals or steering lever mounted controls (not shown) mounted toward the front of operator compartment 40. The general operation of skid steer loaders such as vehicle 10 is well known.
As depicted in FIG. 1, the flail mower 50 is resting on the ground spaced slightly apart from the skid steer vehicle 10 prior to attachment thereto. Preferably the flail mower 50 includes a flail unit 56, which preferably is an Alamo 60 inch VERSA FLAIL or an Alamo 74 inch VERSA FLAIL flail mower, made by the Alamo Company of Seguin, Tex. 78256-0549. The VERSA FLAIL flail units are specifically designed to be mounted in a cantilever manner at the rear of a tractor in a transverse orientation with respect to the center line of the tractor. In such orientation, the VERSA FLAIL flail unit is disposed to the side of the tractor, usually on a telescoping boom, and is useful primarily for cutting the vegetation in ditches alongside road beds. In such use, the tractor drives along the relatively flat surface of the road bed and the VERSA FLAIL flail unit is deployed at a downwardly directed angle along the side of the ditch next to the road bed. It will be understood that other flail units may be used as well.
The flail mower 50 has four major components: case 52, drive unit 54, flail unit 56, and quick attachment receiver 58.
The case 52 of the flail mower 50 has two opposed side panels 60, a top panel 62, a front panel 64, and a rear panel 66 and a rear subpanel 65 extending between top panel 62 and rear panel 66. Rear subpanel 65 includes a plurality of surfaces 67 extending in the lateral direction and angled relatively to each other, as shown in e.g. FIG. 4. Portions of the opposed side panels 60 project above the upper surface of the top panel 62. The underside of the case 52 is generally open to present the vegetation to the cutting blades of the flail unit 56. Front and rear structural tubes 68 are welded to the case 52. The structural tubes 68 enhance the stiffness case 52. A removable drive cover 69 is mounted on the left side of the case 52 as depicted in FIGS. 2 and 3. The case 52 is preferably formed from steel sheets having a thickness of approximately 3/8 of an inch.
The drive unit 54 has a hydraulic motor 70 that is coupled by hydraulic lines 72 to the auxiliary hydraulic system of the skid steer vehicle 10. The hydraulic lines 72 terminate in quick disconnect type couplers for coupling to the auxiliary hydraulic system. A first hydraulic line 72 provides hydraulic fluid under pressure to power the hydraulic motor 70 and a second hydraulic line 72 provides a vehicle for the return of hydraulic fluid to the auxiliary hydraulic system of the skid steer vehicle 10.
The hydraulic motor 70 has a rotatable output shaft (not shown) that is coupled to the drive pulley 74. The drive pulley 74 preferably has two grooves defined therein to accommodate two drive belts 78. An idler pulley 76 rotatably mounted to the side panel 60 of the case 52 is utilized to maintain the desired tension in the drive belts 78. The drive pulley 74, idler pulley 76 and drive belts 78 are substantially enclosed within the drive cover 69.
The hydraulic motor 70 is affixed to the inwardly directed portion of the surface of the side panel 60 that projects above the upper surface of the top panel 62 and is mounted thereon by bolts. A bore (not shown) is defined in the side panel 60 to accommodate the passage of the output drive shaft of the hydraulic motor 70 therethrough.
The hydraulic motor 70 is selected to provide an adequate rotational speed of the flail unit 56 with the amount of hydraulic fluid available from the auxiliary hydraulic system of the skid steer vehicle 10. In a preferred embodiment, the hydraulic motor 70 is capable of rotating the flail unit 56 at a rotational speed of between 1,200 and 1,800 rpm with a desired speed of approximately 1,600 rpm.
The drive belts 78 of the drive unit 54 are rotationally coupled to the flail pulley 84 of the flail unit 56. The flail pulley 84 is fixedly coupled to a rotatable drive shaft 86. The drive shaft 86 spans the full width of the flail mower case 52 and is borne by bearing units (not shown) disposed within bores defined in the opposed side panels 60 of the flail mower case 52.
As depicted in FIG. 3, a plurality of hammers 88 are coupled to the drive shaft 86. Each of the hammers 88 contains one or more sharpened blades disposed at the distal end of the hammers 88. The hammers 88 have a freely pivoting-type coupling to the drive shaft 86, such that the hammers 88 swing freely and comprise the flail portion of the flail unit 56. The cutting mechanism of flail type mowers is known.
As best viewed in FIG. 3, the quick attachment receiver 58 is closely coupled to the flail mower 50 in order to minimize the forward projection of the flail mower 50 when attached to the skid steer vehicle 10. The close coupling has the effect of minimizing the moment that the flail mower 50 imparts to the skid steer vehicle 10 when the flail mower 50 is supported by the lift arms 32.
The quick attachment receiver 58 includes and is supported on a pair of spaced apart gussets 90. The gussets 90 each have a pair of spaced apart generally triangular-shaped side plates 92 and an enclosing top plate 94. The gussets 90 may be formed from a single plate of steel in a brake or press or may be formed by welding the side plates 92 and the top plate 94.
A first edge of the side plates 92 of the gusset 90 is welded to portions of the upper surface of the rear subpanel 65 of the case 52 and to the rear most structural tube 68. The edge margin of a second side of the side plates 92 is welded to a back plate 96, with a back plate 96 being supported by each gusset 90. Alternatively, a single, larger back plate 96 is utilized. The single back plate 96 spans the full distance spanned between the outer edges of the two back plates 96 that are depicted. The single back plate 96 is supported by both the gussets 90, as previously described.
The two back plates 96 are formed in a generally rectangular shape. The upper portion of the back plate 96 is welded to the gusset 90 as previously described. The lower portion of the back plate 96 is welded to the rear panel 66 of the case 52. The lower margin of the back plate 96 is bent upward as depicted in FIGS. 3 and 4 to define a bottom receiver 98. The bottom receiver 98 preferably defines an obtuse included angle with respect to the back plate 96. A guide plate 100 is formed or welded transverse to the outwardly directed margin of each of the back plates 96. The guide plate 100 extends between a portion of the bottom receiver 98 and the back plate 96. At least one locking device hole 102 is defined in each of the bottom receivers 98. The locking device hole 102 is preferably defined in the bottom receiver 98 with an edge thereof disposed proximate the bend defining the juncture between the back plate 96 and the bottom receiver 98.
As viewed in FIG. 3, the two back plates 96 are disposed with respect to the quick attachment mount 35 of the lift assembly 30 with the upper margin thereof tilted away from the quick attachment mount 35. This disposition results in the weight bearing upper portion of the quick attachment mount 35 overlying the case 52 of the flail mower 50 when engaged therewith. This disposition effectively minimizes the moment presented by the flail mower 50 to the skid vehicle 10.
A wedge bar 104 is welded to each of the back plates 96 proximate the upper margin thereof. The wedge bar 104 preferably forms an acute angle with respect to the back plate 96 that defines a downwardly directed lip. As depicted in FIG. 4, the wedge bars 104 for each of the back plates 96 is comprised of a single bar that spans the distance between the two gussets 90, but could as well be individual wedge bars 104 welded to each of the back plates 96.
As depicted in FIGS. 3 and 4, the quick attachment receiver 58 is mounted to the flail mower 50 offset to the left. The offset mounting causes the flail mower 50 to project to the right of the skid steer vehicle 10 when attached thereto. Such projection facilitates the mowing of vegetation that is growing close to a structure on the right side of the skid steer vehicle 10 without causing the skid steer vehicle 10 to strike the structure. It may also be desirable to mount the flail mower 50 centered on the skid steer vehicle 10. A flail mower 50 having greater width than the depicted flail mower 50 would then project on both sides of the skid steer vehicle 10.
As best seen in FIGS. 1 and 3, the upper margin 106 of the quick attaching mount 35 engages the underside of the wedge bar 104 in a wedged fit. The wedged fit comprises the load bearing connection between the mower 50 and the skid steer vehicle 10. Since the load bearing connection point overlies a portion of the flail mower 50, only the portion of the mass of the flail mower 50 that is disposed forward of the load bearing connection point is available to generate a destabilizing moment about the load bearing connection point.
The flail mower 50 may be readily raised with only the aforementioned wedged fit effected between the flail mower 50 and the skid steer vehicle 10. However, in order to ensure that the flail mower 50 is locked in place, rotation of the over-center levers 108 of the quick attaching mount 35 drives spring loaded pins or hooks (not shown) into locking engagement with the locking device holes 102 defined in the bottom receiver 98. The quick attaching mount 35 is locked to the quick attachment receiver 58 in a manner as disclosed in U.S. Pat. No. 3,672,521 to Bauer et al. Since the expiration of the '521 patent, such a quick attaching mount 35 has become widely used in the skid steer vehicle market by the manufacturers of the majority of the skid steer vehicles sold.
In operation, as shown in FIG. 1, the flail mower 50 is supported on the ground surface prior to attaching to the skid steer vehicle 10. The skid steer vehicle 10 is positioned so that the upper margin 106 of the quick attaching mount 35 is adjacent to the wedge bar 104 of the mower 50. The tilt cylinder 37 is then extended to rotate the quick attaching mount 35 clockwise, as depicted in FIG. 1, with respect to the frame assembly 16 so that the upper margin 106 is in position to engage the overhanging lip defined by the wedge bar 104 of the quick attachment receiver 58. From this position, the lift cylinders 36 are extended to raise the lift arms 32 and engage the underside of the wedge bar 104 with the upper margin 106, thereby forming the load bearing connection as seen in FIG. 3. The over-center levers 108 of the quick attaching mount 35 are then manually actuated to drive locking elements such as spring-loaded pins or hooks into locking engagement with the locking device holes 102 defined in the bottom receiver 98, thereby locking the mower 50 to the skid steer vehicle 10. The hydraulic lines 72 are then connected to the auxiliary hydraulic system of the skid steer vehicle 10 by means of the quick disconnect type couplers.
Once attached to the skid steer vehicle 10, the flail mower 50 may be elevated as desired and rotated from the horizontal disposition in order to best perform the mowing operations. The auxiliary hydraulic system of the skid steer vehicle 10 is powered on and off as desired to power the drive unit 54 and engage the flail unit 56 of the flail mower 50.
Detachment of the flail mower 50 from the skid steer vehicle 10 is simply accomplished by reversing the above described procedure.
The present invention provides a safe mowing capability for a skid steer vehicle. Skid steer vehicles are very versatile and a wide variety of attachments or implements have been adapted for use with skid steer vehicles as previously mentioned. There is a need for the safest possible mowing capabilities at a construction site. Adaption of a flail mower implement to a skid steer vehicle has until now been overlooked largely because of the unorthodox steering arrangement of the skid steer vehicle. The present invention is simply constructed and adds a new degree of usefulness to the skid steer vehicle, which will result in improved efficiencies and cost reduction in site preparation in the safest possible manner.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. | An improved skid steer vehicle that has a longitudinally extending main frame and wheels for supporting the main frame for movement over the ground. An operator's compartment spans substantially the entire lateral distance of the main frame in the fore and aft midportions thereof, An engine is contained within an engine compartment disposed rearward of the operator's compartment and includes an auxiliary hydraulic power supply driven off the engine. A pair of spaced apart actuating arms are operably coupled to the main frame at a first end and have a quick attaching mount disposed at a second end thereof. The improvement comprises a flail mower implement that has a quick attachment receiver that is adapted for selective engagement with the quick attaching mount of the pair of actuating arms. |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Application No. 60/258,666, filed Dec. 29, 2000.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to operating railroad locomotives, and more specifically, to controlling locomotives in locomotive consists distributed throughout a train.
[0003] Modem trains may include many train cars and have a length that is over a mile long. Such trains typically contain more than one locomotive to provide the necessary driving and stopping power. To facilitate handling of the train, the additional locomotives often appear at locations in the train that are remote from the lead locomotive. For example, it may be difficult to traverse a curve if all the locomotives are at the front of the train due to high wheel-rail friction and resulting high in-train forces. However, dispersal of locomotives throughout a train requires synchronizing their actions, such as accelerating and braking the locomotives in concert.
[0004] To solve this problem, radio control equipment was introduced thirty years ago so that acceleration and deceleration controls applied to the lead locomotive are transmitted to all others in the remote locomotive consists at substantially the same time. Before the train gets underway the operator links the various radio control units so that they act in concert to send control data to each locomotive consist in the train and return status/alarm information.
[0005] Radio control systems, such as Locotrol®, provide railroads the ability to control locomotives dispersed in a train consist in either a synchronous, or an independent, mode from a control locomotive, which is in the lead position. The system provides control of the remote locomotive consist(s) by command signals sensed at the lead locomotive and transmitted over a data radio link to the remote unit(s). Such control systems allow railroads to optimize the distribution of motive power and braking control over the length of a train. Radio control systems provide faster and smoother starting and stopping of trains, facilitating safer handling and more efficient operations. In addition, they also facilitate increasing rail system throughput and reducing operating costs from the increased hauling capacity, better rail adhesion, and improved fuel efficiency.
[0006] Radio controls now play a crucial role in operating large trains safely, which poses a problem in upgrading the software used in the radio control systems. At present units with different versions of radio control software cannot be operated in the same train, this forcing users to operate such locomotives separately. This requirement also imposes a heavy logistical burden on users while the software on the locomotive fleet is being upgraded and increases pressure on software vendors to upgrade the software in all locomotives as quickly as possible to minimize this problem. Safety considerations, however, preclude an automatic radio download of the upgraded software, which necessitates the vendor physically installing and testing the software on each locomotive in a short time.
BRIEF DESCRIPTION OF THE INVENTION
[0007] In one aspect, a method is provided of upgrading control software on a first locomotive. The first locomotive includes a first locomotive interface. A first computer is coupled to the first locomotive interface, and a first communicator is coupled to the first computer. The first computer is programmed for operation on the first locomotive. The method includes loading a first version of control software onto the first computer, loading a second version of control software onto the first computer, and using data included in a link message to determine whether the first version or the second version of the control software is used.
[0008] In another aspect, a system is provided for controlling a first locomotive. The system includes a first locomotive interface, a first computer that is coupled to the locomotive interface, and a first communicator that is coupled to the first computer. The first computer is programmed to control the first locomotive. The first computer is further programmed to use at least one of a first version of control software and a second version of control software.
[0009] In a further aspect, a fleet of locomotives is provided that include at least one locomotive equipped with a system for controlling the at least one locomotive. The system includes a first locomotive interface, a first computer coupled to the first locomotive interface, and a first communicator coupled to the first computer. The first computer is programmed to control the at least one locomotive and to use a first version of control software and a second version of control software.
[0010] In yet another aspect, a method is provided for upgrading control software on a first locomotive. The first locomotive includes a first locomotive interface, a first computer coupled to the first locomotive interface, and a first communicator coupled to the first computer. The first computer is programmed for operation on the first locomotive. The method includes providing the control software with functionality to operate with a plurality of locomotive control system configurations, and using data included in link messages to determine which version of the control software is used.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] [0011]FIG. 1 shows a block diagram of a locomotive control system.
[0012] [0012]FIG. 2 is a flowchart illustrating an exemplary overall linking process between the locomotive consists in a train.
[0013] [0013]FIG. 3 is a block diagram illustrating an exemplary software memory module/software partition.
[0014] [0014]FIG. 4 is a flowchart depicting in detail the linking process between an non-upgraded lead unit and both an upgraded and non-upgraded remote unit.
[0015] [0015]FIG. 5 is a flowchart depicting in detail an exemplary embodiment of the linking process between an upgraded lead unit and both an upgraded and non-upgraded remote unit.
DETAILED DESCRIPTION OF THE INVENTION
[0016] As used herein, the term “locomotive consist” means one or more locomotives physically connected together, with one locomotive designated as the controlling locomotive and the others as trailing locomotives. A “train” consist means a combination of cars (freight, passenger, bulk) and at least one locomotive consist. Typically, a train is built in a terminal/yard and the locomotive consist is at the head-end of the train. Occasionally, trains require additional locomotive consists within the train consist or attached to the last car in the train consist. Additional locomotive consists sometimes are required to improve train handling and/or to improve train performance due to the terrain (mountains, track curvature) in which the train will be traveling. A locomotive consist at the head-end of a train may or may not control locomotive consists within the train.
[0017] [0017]FIG. 1 shows a block diagram 10 of an on-board control system for a locomotive. System 10 includes a locomotive interface 12 that operatively connects the controls of the locomotive to a computer 14 . Computer 14 is also operatively connected to a communicator 18 . Signals received by communicator 16 are relayed to computer 14 , which controls the motion of the locomotive through locomotive traction, dynamic brake and air brake interfaces 12 . In one embodiment communicator 18 is a satellite communicator, but other types of communicators suitable for this application will be readily apparent to those skilled in the relevant art.
[0018] [0018]FIG. 2 is a flowchart 20 illustrating an exemplary general process that is followed when a train is assembled to link locomotives equipped with the on-board control system shown in FIG. 1. From the onset of operation of the train, locomotives exchange link messages that include a link command from the lead locomotive to a remote locomotive, and a link reply in response to the link command. A link command relating to the versions of control software is sent from the communicator on a lead locomotive to the communicator on a remote locomotive in the train. If all checks are successful, the second locomotive responds with a link reply that contains a specification of the version of control software matching the lead unit version. The computer on the lead locomotive then uses the specification of the version of control software on the remote locomotive's computer to select a mutually compatible version of control software and, if necessary, command previously-linked remote units to the same software version.
[0019] A first communicator that is operatively coupled to a first computer on a lead locomotive sends 22 a link command to a second communicator that is operatively coupled to a second computer on a remote locomotive which has previously been enabled. The first computer includes two versions of control software loaded onto it, referred to here as the primary version and the secondary version. These two versions would typically correspond to new and previous versions of control software, but as will be readily appreciated, how the versions differ is not critical, and versions differing in other respects would work equally well in the inventive method and system. The second communicator responds 24 to the first communicator with a link reply that contains a specification of the version of control software in use on the second computer. The first computer then selects 26 a version of control software to use based upon the specification received from the second communicator, and displays 28 to the railroad crew the version it selected, as well as the significant operational aspects.
[0020] If the two versions of control software correspond to the primary and the secondary version, system 10 selects the primary version only if all locomotives in the train can utilize the primary version. If any locomotive in the train has not yet been upgraded, and all locomotives support the secondary version, system 10 selects the secondary version so that all locomotives can still operate properly. The selection of software version is transparent to the railroad crew. Once a link has been achieved, system 10 displays on a console a message advising the crew of the implications of the version of software that has been selected.
[0021] [0021]FIG. 3 is a block diagram 30 illustrating a software memory module/software partition 32 . Each computer 14 includes a central processing unit (CPU) 34 and the functionality 36 for the latest version (primary) of software for lead unit operation, the functionality 38 for the latest version (primary) of software for remote unit operation, the functionality 40 for a previous version (secondary) of software for lead unit operation, and the functionality 42 for a previous version (secondary) of software for remote unit operation. In one embodiment, each computer 14 also includes diagnostics and link functions 44 . A numeric code is associated with each software version. For example, an un-upgraded unit might have 45 and 49 respectively for the secondary and primary codes, and an upgraded unit might have 49 and 50 respectively from the secondary and primary codes.
[0022] The primary and secondary control functions 36 , 38 , 40 , and 42 are isolated to minimize software code generation and testing when an upgrade is performed. The primary link command from the lead unit includes two software version codes. The primary code indicates the latest software version installed. The secondary code indicates the previous software version installed. If the addressed remote unit includes the software corresponding to the link command primary code, the addressed remote unit responds in the link reply with the link command primary code. If the remote unit does not include the software corresponding to the link command primary code, but does include the software corresponding to the secondary code, the remote unit responds in the link reply with the secondary code. If any remote unit is linked with the lead unit secondary version code, the lead unit re-links all remote units using only the secondary code.
[0023] [0023]FIG. 4 is a flowchart 50 showing in detail how system 10 works with an non-upgraded lead locomotive 52 , that is a lead locomotive with onboard control system software that has not been upgraded with new software. Non-upgraded lead locomotive 52 , in response to selection of a LINK key by the railroad crew, transmits 54 to other locomotives in the train a link command that includes two lead version codes. An upgraded remote locomotive 56 that receives the link command compares the primary lead version codes and finds that it matches 58 its secondary version code. Locomotive 56 then responds 60 to locomotive 52 with a secondary version code, and is then linked 62 to locomotive 52 as a “current” remote locomotive.
[0024] A non-upgraded remote locomotive 64 that receives the link command compares the primary lead version code and finds that it matches 66 the secondary version code present on locomotive 64 . Locomotive 64 then responds 68 to locomotive 52 with its primary version code, and is then linked 69 to locomotive 52 as a “current” remote locomotive. Thus an upgraded lead locomotive can function with both upgraded and non-upgraded remote locomotives, with the former making the necessary accommodation to link to the non-upgraded lead locomotive.
[0025] [0025]FIG. 5 is an exemplary flowchart 70 illustrating how system 10 functions with an upgraded lead locomotive 72 , or more specifically, how system 10 functions with a lead locomotive including an on-board control system that has been upgraded with new software. Upgraded lead locomotive 72 , in response to selection of a LINK key by the railroad crew, transmits 74 to other locomotives in the train a link command that includes two lead version codes corresponding to a primary software version and a secondary software version. An upgraded remote locomotive 76 that receives the link command compares the primary lead version code to determine if it matches 78 a primary version code. If it matches 78 , locomotive 76 then responds 80 to locomotive 72 with a primary version code, and is then linked 82 to locomotive 72 as a “new” remote locomotive.
[0026] A non-upgraded remote locomotive 84 that receives the link command compares the secondary lead version code to determine if it matches 86 a primary version code. If it matches 86 , locomotive 84 then responds 88 to locomotive 72 with its primary remote version code, and is then linked 90 to locomotive 72 as a “ccurrent” remote locomotive.
[0027] If any locomotive is linked as a lead secondary remote locomotive, upgraded lead locomotive 72 then links 92 all remote locomotives in the train as “current” remote locomotives, including those previously linked as “new” locomotives.
[0028] Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only and is not to be taken by way of limitation. Accordingly the spirit and scope of the invention are to be limited only by the terms of the appended claims and their equivalents. | A method of upgrading control software on a first locomotive. The first locomotive includes a first locomotive interface. A first computer is coupled to the first locomotive interface, and a first communicator is coupled to the first computer. The first computer is programmed for operation on the first locomotive. The method includes loading a first version of control software onto the first computer, loading a second version of control software onto the first computer, and using data included in a link message to determine whether the first version or the second version of the control software is used. |
RELATED CASE
This application is a continuation-in-part of application Ser. No. 13/904,846 filed on May 29, 2013 and which priority for this application was claimed under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/755,525 which was filed on Jan. 23, 2013, and each of which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
The present invention relates in general to jewelry and pertains, more particularly, to various pieces of jewelry or bangles that have been infused with tesla energy to add a new and novel aspect to the jewelry.
BACKGROUND OF THE INVENTION
Various types of jewelry exist. For example, loop-type bracelets are well known and some of these bracelets may even be provided with charms. However, the bracelet itself, as well as the charms, are essentially inert and there is no interaction between adjacent bracelets nor between a bracelet and a charm, tag or the like.
Accordingly, it is an object of the present invention to provide an improved jewelry item and, in particular, a bracelet, although the principles of the present invention may also apply to other jewelry items such as necklaces or pendants. In accordance with the present invention, tesla energy is used as a means by which adjacent bracelets can be attracted or repelled from each other and charms can be affected as to their motion on a bracelet.
SUMMARY OF THE INVENTION
A tesla energy jewelry product is comprised of a pair of substantially circular bangles that may be placed in juxtaposition to each other. Each substantially circular bangle carries either a tag or decorative charm that is suspended from the substantially circular bangle, with each tag or decorative charm including a source of magnetic or tesla energy to provide attractive or repelling forces between the respective tag or decorative charm.
In accordance with other aspects of the present invention the tag or decorative charm is fixedly secured to the bangle; the respective charms each have a jagged edge, and the jagged edges of respective charms are constructed and arranged to matingly engage when the magnetic or tesla energy is applied; the respective charms each have an interlocking edge, and the interlocking edges of respective charms are constructed and arranged to interlock with each other to form a completed charm when the magnetic or tesla energy is applied; the tag or decorative charm is pivotally secured to the bangle; the bangle includes a bangle shaft the tag or decorative charm is constructed and arranged with a loop that extends about the bangle shaft; in combination with a separate energy source that is magnetic or of tesla energy and that is useable to form an attraction between the energy source and the tag or decorative charm to move the tag or decorative charm about the bangle shaft; in combination with a separate energy source that is magnetic or tesla energy and that is useable to form an attraction between the energy source and the tag or decorative charm; and the tag or decorative charm is comprised of an outer ring for rotationally supporting a center piece, the separate energy source for controlling rotation of the center piece relative to the outer ring.
In accordance with another embodiment of the present invention there is provided a tesla energy jewelry product that is comprised of a substantially circular bangle that carries either a tag or decorative charm that is suspended from the substantially circular bangle, said tag or decorative charm including a source of magnetic or tesla energy to provide attractive or repelling forces.
In accordance with still other aspects of the present invention the tag or decorative charm is fixedly secured to the bangle; the decorative charm or tag has an interlocking edge, and the interlocking edge may mate with another decorative charm or tag; the tag or decorative charm is pivotally secured to the bangle; the bangle includes a bangle shaft and the tag or decorative charm is constructed and arranged with a loop that extends about the bangle shaft; in combination with a separate energy source that is magnetic and that is useable to form an attraction between the energy source and the tag or decorative charm to move the tag or decorative charm about the bangle shaft; in combination with a separate energy source that is magnetic and that is useable to form an attraction between the energy source and the tag or decorative charm; the tag or decorative charm is comprised of an outer ring for rotationally supporting a center piece, the separate energy source for controlling rotation of the center piece relative to the outer ring; the tag or decorative charm is a two part piece including a base portion and a removable top portion; and both the base and top portions are magnetic and constructed and arranged for an attractive force therebetween.
In accordance with another embodiment of the present invention there is provided a tesla energy jewelry product that is comprised of a substantially circular bangle having opposed bangle ends and a pair of end caps disposed at the opposed ends of the bangle. The respective end caps include a source of magnetic or tesla energy to provide attractive or repelling forces.
DESCRIPTION OF THE DRAWINGS
In accordance with the present invention there are now set forth in FIGS. 1-11 multiple different versions of the present invention including one or more bangles; the use of a separate energy source; fixed, pivotal and rotational aspects of the tag or charm; the use of a code on the charm, tag or bangle; the use of tesla energy via magnetism along with crystal therapy; and a port arrangement for containing the energy source as part of the bangle configuration, but removable for use in motioning.
FIG. 1 schematically represents a first embodiment;
FIG. 2 schematically represents a second embodiment;
FIG. 3 schematically represents a third embodiment;
FIG. 4 schematically represents a fourth embodiment;
FIG. 5 schematically represents a fifth embodiment;
FIG. 6 schematically represents a sixth embodiment;
FIG. 7 schematically represents a seventh embodiment;
FIG. 8 schematically represents an eighth embodiment;
FIG. 9 schematically represents a ninth embodiment;
FIG. 10 schematically represents a tenth embodiment;
FIG. 11 schematically represents an eleventh embodiment;
FIG. 12 is a perspective view illustrating still a further embodiment of the present invention wherein the bracelet is in a closed position;
FIG. 13 is a perspective view similar to that shown in FIG. 12 with the bracelet in an open position;
FIG. 14 is a top plan view of the bracelet illustrated in FIGS. 12 and 13 ;
FIG. 15 is a cross-sectional view taken along line 15 - 15 of FIG. 14 ; and
FIG. 16 is a schematic representation of another form of interlocking charm construction.
DETAILED DESCRIPTION
FIG. 1 describes a bracelet 10 . The construction of this bracelet 10 may be like that shown in U.S. Design Pat. No. D498,167. In addition, various other styles of bracelet, bangle, necklace or pendant may also be employed. FIG. 1 illustrates the tesla energy tag 12 and an arrow 13 shows the attraction between the tags and thus between the bracelets. The tesla energy tags can be directly energized. When the tags are near each other, you can “see” and “feel” their energy force. This energy force is in the form of a magnetism. Thus, the two separate tags 12 illustrated in FIG. 1 may have facing magnets that provide the attraction force. As is known, each magnet has a north pole and a south pole and depending upon how they are situated they can either attract to each other or repel each other. For the most part they should attract. Thus the magnets in the respective tags 12 are constructed and arranged for attraction therebetween.
Refer now to FIG. 2 which also shows the same bracelet arrangement at 10 . Also included are flat charms 14 . These charms may be directly energized so that when they are near each other they connect (arrow 15 ) and you can “see” and “feel” the energy between them. It is noted that each of the charms 14 has a jagged edge and when they are attracted to each other, these jagged edges may interlock. This jagged edge interlock is only one of a number of different interlock arrangements that may be provided. In this regard refer to the schematic diagram of FIG. 16 that shows charm portions 14 in which the interlock is by means of an oval surface. In both FIGS. 1 and 2 the tag 12 and charms 14 may be fixedly secured to the bracelet or may be pivoted from the bracelet. Again, magnets are used imbedded in each charm 14 to provide the attraction force. Also, magnets can be provided in the respective bangles 10 , such as imbedded in the bangle shaft at a location therealong. FIG. 2 also shows at 15 the use of a bar code on a portion of the charm 14 . FIG. 2 also illustrates an option on the left-hand portion of the charm 14 in which an RFID chip 15 A is embedded in the charm. Most likely, either the bar code or the RFID chip is used in a single charm.
In FIG. 2 the bar code that is illustrated can contain such information as business contacts, addresses, telephone numbers and in that regard can be used to replace a typical business card. There is thus no need for printing business cards. The bar code can also contain medical information. This would thus provide ready and easy access to medical information. For example, an EMT can scan the charm/bar code and obtain the medical history of a person in the case of an emergency.
Reference is now made to FIG. 3 that also shows the bracelets 10 with coupling energy indicated by the arrow 16 . In this embodiment each bracelet or bangle is energized by tesla energy so that when the bracelets are near each other you can “see” and “feel” the energy between them. The bangles are directly infused with tesla energy. This also works for tesla energy therapy wherein the bangles can be constructed and arranged so as to be always in the optimal positioning for energy interconnection. Also, magnets can be provided in the respective bangles 10 , such as imbedded in the bangle shaft at a location therealong.
Reference is now made to FIG. 4 for still another embodiment of the present invention. This shows a single bracelet or bangle at 10 and an energized charm at 18 . The charm may take on many different forms and is illustrated as a dancer. The charm 18 is constructed so that it can move at its base 19 about the bracelet. For this purpose the very bottom of the charm 18 may have a hole or passage through which the bangle shaft is arranged. The fit with the shaft is close but allows a sliding motion between the bangle and charm. This movement can be controlled by the external tesla energy power source 20 . Another version of this is shown and discussed hereinafter in connection with FIG. 9 . In FIG. 4 the connection at 19 enables the charm to move about the shaft of the bracelet under control of the energy source 20 . For this purpose a magnet is provided somewhere in or at the charm 18 and another magnet is provided in or at the source 20 . The magnets may be rated for different force values depending upon the particular application. By moving the source 20 in an arc close to the charm 18 , one can move the charm 18 in a like arc about the bangle shaft.
Refer now to FIG. 5 for another embodiment of the present invention. In this embodiment the bracelet 10 has respective end caps 24 . These end caps are energized with tesla energy so that when the bangles are near each other you can “see” and “feel” the energy of the energy force between them. The energized end caps can be plain, decorative or otherwise. The end caps are preferably placed in an optimal area for tesla energy therapy purposes. Magnets may be used imbedded in each end cap 24 to provide the attraction force. Also, magnets can be provided in the bangle 10 , such as imbedded in the bangle shaft at a location therealong, or at multiple locations therealong.
Reference is now made to FIG. 6 which shows an arrangement similar to that described in FIG. 4 but illustrating a different charm 26 . The charm 26 is also connected with the bracelet shaft so that it can rotate in opposed directions such as indicated by the arrows 27 in FIG. 6 . This movement is controlled by the tesla energy infused source 20 shown adjacent to the charm 26 . There is preferably provided an attractive force between the source 20 and the charm 26 so that the source can be moved to provide a corresponding movement of the charm 26 about the circular path defined by the shaft of the bracelet. For this purpose the charm 26 can be provided with a hole or passage at its base for accommodating the bangle shaft. The fit with the shaft is close but allows a sliding motion between the bangle and charm. This movement can be controlled by the external tesla energy power source 20 . For this purpose a magnet is provided somewhere in or at the charm 26 and another magnet is provided in or at the source 20 . The magnets may be rated for different force values depending upon the particular application. By moving the source 20 in an arc close to the charm 26 , one can move the charm 26 in a like arc about the bangle shaft.
Refer now to a further illustration in FIG. 7 . This includes three dimensional charms 30 that have been infused with tesla energy. In other words these charms have been magnetized with a certain polarity magnetization. They may be magnetized so as to be in an attractive relationship in the direction indicated by arrow 31 in FIG. 7 . Each of the charms 30 may be fixed to the bracelet or may be pivoted from the bracelet. For this purpose a magnet is provided somewhere in or at each of the charms 30 . The magnets may be rated for different force values depending upon the particular application.
Refer now to FIG. 8 for an illustration of a charm 34 attached to the bracelet 10 . The charm 34 includes a center piece 35 that may be adapted to spin relative to an outer ring 36 . The tesla energy source 20 can control the spinning of the center piece 35 when it is put near to the charm. The arrow in FIG. 8 depicts the force field between the source 20 and the center piece 35 . By rotating the source relative to the charm 34 one can cause the rotation of the center piece 35 relative to the outer ring 36 . The outer ring 36 is preferably fixed to the bangle shaft so that only the center piece 35 rotates based on the force imposed by the source 20 .
Reference is now made to FIG. 9 for an important embodiment of the present invention. This also illustrates a bracelet 10 with a charm at 40 . This charm is actually a two piece arrangement including a base portion 42 and a removable top 44 . The two pieces 42 and 44 are adapted for attraction to each other by the application of tesla energy. Thus a magnet is provided in each of the pieces 42 , 44 for providing the needed attraction force. The piece 44 is removable and functions as the tesla energy source 20 . This can be used as the energy power source needed to activate charms such as described previously in connection with FIGS. 4 and 6 . The exposed surface of the piece 44 may be plain or may be provided as a decoration with a three-dimensional design. This two piece construction can also be associated with a pendant in which one of the pieces can be taken off of the pendant and used as a controlling tesla energy source 20 .
Reference is now made to FIG. 10 for still another embodiment of the present invention. This shows a single bracelet or bangle at 10 and an energized charm at 48 . The charm may take on many different forms and is illustrated as a motorcycle. The charm 48 is constructed so that it either is movable at its base about the bracelet shaft or can be fixed in position or pivotal relative to the bracelet shaft. For this purpose the very bottom of the charm may have a hole or passage through which the bangle shaft is arranged. The fit with the shaft is close but allows a sliding motion between the bangle and charm. This movement can be controlled by the external tesla energy power source 20 that is not shown in FIG. 10 . In FIG. 10 the bangle or bracelet includes a base 50 that one part of the bangle shaft extends through a hole 51 . The base 50 is of rectangular shape and houses a magnet 52 which is preferably contained behind a crystal 54 . This provides a dual effect of the tesla energy and crystal therapy. Likewise the charm 48 may have a magnet 55 imbedded therein and covered by the crystal 56 .
FIG. 10 also shows another feature of the present invention of either a code 60 on the base 50 or a code 62 on the bangle shaft. This may be a bar code or any other form of readable code. Also shown is a smart phone at 64 that can be used for reading the code and associating the code with a particular business. The code arrangement described can be used with any of the many versions that have been described herein. An RFID chip may also be used on the base 50 , charm 48 or the bangle itself.
Reference is now made to FIG. 11 for still another embodiment of the present invention. This also illustrates a bracelet 70 with a base at 72 . The base 72 has side-by-side holes or passages for receiving sections of the bangle shaft. Respective balls may be provided at the free ends of the bangle shaft, as illustrated. This base 72 is actually a two piece arrangement including a base portion 74 and a removable top 76 . The two pieces 74 and 76 are adapted for attraction to each other by the application of tesla energy. Thus a magnet is provided in each of the pieces 74 , 76 for providing the needed attraction force. The piece 76 is removable and functions as the tesla energy source. This can be used as the energy power source needed to activate charms such as described previously in connection with FIGS. 4 and 6 . The exposed surface of the piece 76 may be plain or may be provided as a decoration with a three-dimensional design. This two piece construction can also be associated with a pendant in which one of the pieces can be taken off of the pendant and used as a controlling tesla energy source.
The base 74 preferably has a recess 77 in which the magnet 78 is disposed. At least a part of the top portion or disc 76 is sized to fit within the recess 77 . The top portion 76 also contains a magnet 79 that is adapted for coupling with the magnet 78 to provide the attraction force between the base portion 74 and top portion 76 . Thus, the top portion can be held by the base but be in readiness for use such as in the version of FIG. 10 wherein the top portion functions as a removable energy source useable to move other items such as a charm or tag or other items. Although not shown in FIG. 11 other charms can be attached to the bangle shaft some of which can contain a magnet for attraction purposes.
Reference is now made to still another embodiment of the present invention illustrated in FIGS. 12-15 that has some of the similarities of the embodiment of FIG. 6 that enables the separate energy source 80 to control the charm 82 . The energy source 80 may be similar to that previously described including a magnet M to provide attractive forces. In the embodiment of FIGS. 12-15 , the bracelet is illustrated at 84 . At one end of the bracelet, there is a ball 85 and a reverse hook or loop 86 that enable that end of the bracelet to be secured with a loop 87 at the opposite end of the bracelet. The loop 87 is formed by a reverse bend through 180 degrees with the very terminal end forming a further loop 88 that is disposed about the bracelet shaft 89 terminating in a ball 91 .
FIG. 12 illustrates the closed position of the bracelet wherein the loop 86 and ball 85 are engaged with the opposite end of the bracelet at the large loop 87 . FIG. 13 is a perspective view illustrating the bracelet in an open position wherein the loop 86 has been disengaged from the loop 87 . This engagement and disengagement can take place quite easily by simply moving the loop 86 into the loop 87 which may require some deflection of the loop 86 in an upward or downward direction. The loop 86 may be considered as an open loop that enables engagement with the loop 87 which may be considered a closed loop. The loop 87 thus is defined by adjacent spaced apart legs 90 and 92 that define an opening that represents a path for receiving the charm 82 .
Reference may now be made to FIGS. 14 and 15 and in particular the cross-sectional view of FIG. 15 that shows further details of the charm 82 . The charm 82 has a top section 93 that may support the decorative item 94 such as a piece of jewelry. The charm 82 also includes a bottom section 95 and between the sections 93 and 95 there is provided an annular slot 96 . It is the annular slot 96 that rides within the legs 90 , 92 and provides a slot track for receiving the charm. The charm is supported in a relatively loose manner but still confined between the legs 90 , 92 but is readily able to be moved along these legs under control of the energy source. FIG. 15 also illustrates the embedded magnet 97 that interacts with the energy source 80 . Thus, by movement of the energy source 80 in the direction of arrows X, one can cause movement of the charm 82 between and along the legs 90 and 92 . This movement is illustrated in the drawings by arrows Y.
Having now described a limited number of embodiments of the present invention, it should now be apparent to one skilled in the art that numerous other embodiments and modifications thereof are contemplated as falling within the scope of the present invention. For example, any of the versions disclosed can be altered with teachings from other versions illustrated herein. | A tesla energy jewelry product includes a pair of substantially circular bangles that may be placed in juxtaposition to each other. Each substantially circular bangle carries either a tag or decorative charm that is suspended from the substantially circular bangle. Each said tag or decorative charm includes a source of magnetic or tesla energy to provide attractive or repelling forces between the respective tag or decorative charm. |
[0001] The present invention relates to a basic housing for a wheel hub motor, wherein the basic housing has a receiving area for a stator, having at least one stator housing section for situating the stator, cooling channels for cooling the stator being situated in the stator housing section, and a wheel hub motor having this basic housing.
BACKGROUND
[0002] In electric vehicles, i.e., vehicles which are driven via an electric motor, in addition to centrally situated electric motors, which supply, for example, two wheels of a driven axle with a drive torque via a transmission, the concept of the wheel hub motor has also become established, the electric motor being installed directly on or in the wheel.
[0003] One example of such a wheel hub motor is found in document DE 20 2011 108 560 Ul. It relates to a wheel hub motor which has a motor receiving body and a rim body, the rim body being mounted so it is rotatable in relation to the motor receiving body and being able to be driven by a motor. The motor receiving body and/or the rim body may essentially be manufactured from and/or include a fiber-plastic composite.
[0004] Document DE 10 2011 081 503 B4, which represents the most proximate related art, describes a wheel hub drive system having an electric motor which may be situated inside a rim. The stator of the electric motor is connected to a stationary housing section of the wheel hub drive system. A ring-shaped cooling element having cooling channels, to which a coolant liquid, in particular water or a water-glycol mixture, is applied, is located on the radial outside of the stator. The cooling element is designed as a sleeve, on the radial outer side of which the cooling structures are introduced and which are sealed closed using a second sleeve.
SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to provide a basic housing for a wheel hub motor, which may also be mass manufactured cost-effectively.
[0006] In the scope of the present invention, a basic housing is provided which is suitable and/or designed for a wheel hub motor of a vehicle. The vehicle may be a passenger automobile, for example. Alternatively, however, it may also be provided that the vehicle is designed as a three-wheeled or two-wheeled vehicle, in particular as a motorcycle. The vehicle has at least one wheel hub motor, the wheel hub motor replacing a conventional wheel of the vehicle. The vehicle may have multiple such wheel hub motors, in particular the vehicle has two wheel hub motors on one axle.
[0007] The basic housing is situated in a frame-fixed and/or stationary way in relation to the vehicle in operation and forms a bearing partner to the tire of the wheel, which rotates in operation. The basic housing and/or the wheel hub motor defines a main axis of rotation, about which the wheel rotates.
[0008] The basic housing has a receiving area for a stator. The stator is part of an electric motor for the wheel hub motor and therefore participates in generating the drive torque of the wheel hub motor. In particular, the electric motor is designed as a permanently-excited synchronous motor.
[0009] The basic housing includes a stator housing section for situating the stator. Cooling channels for cooling the stator are situated in the stator housing section. The stator housing section particularly preferably forms a stator receiving area or delimits it in a radial direction in relation to the main axis of rotation. In particular, the stator housing section provides a cylinder jacket surface, which is situated coaxially and/or concentrically in relation to the main axis of rotation. The cylinder jacket surface forms a radial contact surface for the stator. In particular, the cooling channels form a cooling jacket for the stator.
[0010] In the scope of the present invention, it is provided that the basic housing includes a cooling device, which forms the cooling channels. The stator housing section is formed from a plastic, it being provided that the cooling device is at least sectionally embedded in the plastic as a first insert in the stator housing section. The cooling device is therefore formed as a separate component, which is embedded in the plastic of the stator housing section. In particular, the cooling device is embedded in the plastic as the first insert during a primary molding process or a shaping process of the stator housing section.
[0011] It is one consideration of the present invention that the introduction of cooling channels is complex in manufacturing if they are introduced, for example, into a material by a severing method. On the other hand, it is very simple to produce a separate cooling device, which has an arbitrary shape, because all available manufacturing technologies may be used for this purpose. Therefore, it is provided in the scope of the present invention that the cooling device be designed as a first insert, because it may be manufactured as a functional module with the aid of any arbitrary manufacturing technology in a simple and/or coolant-tight way.
[0012] The cooling device is subsequently embedded in the plastic to form the stator housing section. This procedure has the advantage that the stator housing section is weight-optimized as a result of the plastic used and additionally may be manufactured cost-effectively because of the use of plastic as a material. Therefore, it is achieved by the present invention that embedding the cooling function into the basic housing, it is suitable for mass production, may be manufactured cost-effectively, is mass-optimized and/or weight-optimized, and may be optimized to the installation space.
[0013] In one preferred implementation of the present invention, the stator housing section is designed as a plastic injection molded part section, the cooling device being extruded into, around, or onto the plastic injection molded part section as the first insert. Plastic injection molding is a process suitable for mass production, which combines short cycle times with low manufacturing costs and good functional properties of the final product.
[0014] In one preferred structural embodiment of the present invention, the cooling device has a cooling jacket section. In particular, the cooling jacket section is designed as a closed ring shape or as a hollow-cylindrical shape. The stator housing section includes an annular wall section and is formed in particular as an annular wall. The annular wall section has a delimitation surface facing toward the stator, wherein the delimitation surface is designed as a cylinder jacket surface, which is aligned coaxially and concentrically in relation to the main axis of rotation. In particular the annular wall section, and in particular the annular wall, has a hollow cylindrical shape. The delimitation surface of the stator housing section facing away from the stator may also be implemented as desired, however. The cooling jacket section is situated in the annular wall section, in particular in the annular wall. In this embodiment, the stator may be cooled over the complete width of the stator housing section and/or the cooling jacket section, without requiring a large installation space.
[0015] In one preferred refinement of the present invention, the cooling jacket section rests exposed or open on a side facing toward the stator, so that it forms a part of the contact surface for the stator. Because the thermal conductivity of plastic is limited, it may be ensured in this way that the thermal contact between the cooling device and the stator is improved. The cooling device, in particular the cooling jacket section, may also be made, for example, of plastic, glass, ceramic components, or -particularly preferably in this embodiment—a metallic material, which has particularly good thermal conductivity.
[0016] In one preferred refinement of the present invention, the cooling jacket section is designed as a cooling coil section having cooling coils. The cooling coils are implemented in particular as pipes or lines. For example, the cooling coils are wound in a spiral circumferentially around the main axis of rotation or extend in a meandering shape in the axial direction. In the preferred embodiment, it is provided that the cooling coils are flattened in a cross section, which is perpendicular to the longitudinal extension of the cooling coils and/or perpendicular to a flow direction of the coolant in the cooling coils, on the side facing toward the stator. Due to the flattening, the surface component of the cooling jacket section on the contact surface of the stator housing section for the stator is increased, so that the thermal conductivity is improved. Alternatively thereto, the cooling jacket section may be designed having a coolant conducting structure, the cooling channels being connected to one another in a network.
[0017] In another embodiment of the present invention, it is ensured that the contact surface of the stator housing section facing toward the stator is made entirely from plastic over the entire area, so that a plastic area remains between the cooling device, in particular the cooling jacket section, and the contact surface. In this embodiment, the surface contact between stator and stator housing section is not interrupted by insulating air areas, which may result as inhomogeneities in the transition area between the cooling device and the plastic of the stator housing section. To make this plastic area particularly thermally conductive, a particularly thermally-conductive plastic may optionally be used for the stator housing section. It is also possible that the stator housing section includes two plastic components, the plastic area between the cooling jacket section and the stator being made of a plastic which has a better thermal conductivity than the remainder of the plastic.
[0018] To avoid insulating air areas between the contact surface of the stator housing section and the stator due to incomplete introduction of the plastic, in particular incomplete injection of the plastic, it is provided that the cooling coils taper conically and/or to a point in the mentioned cross section in the direction of the contact surface, to facilitate the extrusion coating and/or the flowing together of the plastic in the plastic area. This embodiment is based on the consideration that, for reasons of manufacturing technology, the plastic flows from a greater wall thickness to a lesser wall thickness.
[0019] In another alternative of the present invention, a coupling layer made of a heat-conductive material, in particular plastic, is introduced between the stator carrier section and the stator, which, on the one hand, implements the mechanical securing of the stator on the stator carrier section and, on the other hand, implements improved thermal coupling between stator and stator housing section.
[0020] In one possible refinement of the present invention, the housing includes a stator carrier section which is connected to the stator housing section. The stator carrier section delimits a stator receiving area, which is formed by the stator housing section, in an axial direction in relation to the main axis of rotation. The stator carrier section is formed on the stator housing section. On the one hand, it may be provided that the basic housing has a second insert, which is embedded in the same plastic as the cooling device and which is formed as a metal part, for example, which implements the mechanical stability of the stator carrier section. Alternatively thereto, the stator carrier section may also be made exclusively of plastic, so that the basic housing may be manufactured particularly cost-effectively. In particular, the stator carrier section and the stator housing section are produced in one piece in a single manufacturing step by plastic injection molding.
[0021] In one refinement of the present invention, the basic housing includes an electronics receiving section for accommodating power electronics and/or control units and/or inverter devices for inverting a direct current from the vehicle into an alternating current for the electric motor. The electronics receiving section is situated on the stator carrier section, but is preferably positioned on a side facing away from the stator housing section. Therefore, the stator carrier section forms a partition wall between the stator housing section and the electronics receiving section. The electronics receiving section is formed on the stator housing section and/or on the stator carrier section. The electronics receiving section may also be produced by the same plastic, in particular by the same plastic injection molding method step, as the stator housing section and/or the stator carrier section. It is particularly preferably provided that the electronics receiving section, the stator housing section, and the stator carrier section are formed in one piece and are produced as a single plastic part.
[0022] In advantageous refinements of the present invention, the cooling device has further cooling sections, which extend through the electronics receiving section and/or through the stator carrier section, and which cool the mentioned sections using coolant. This refinement has the advantage that the cooling device may be extrusion coated as the first insert, for example, in a single plastic injection molding method step, to form the basic housing including the stator housing section and optionally in addition the stator carrier section and/or the electronics receiving section and to form an integrated cooling for them. Alternatively or additionally, it may be provided that the cooling device is formed as the winding heads.
[0023] In one possible refinement of the present invention, the basic housing includes the stator, the stator being formed as a further insert, which is embedded in the plastic. In particular, the stator is embedded in the plastic by the same plastic injection molding method step. This embodiment has the advantage that the relative position between stator and the stator housing section is fixed in an integrally joined way by the plastic. Optionally, the electronics of the wheel hub motor, in particular the power electronics and/or the control units and/or the inverter devices, may additionally be designed as a next insert, which is embedded in the plastic. In particular, the electronics including the interconnection and the winding heads and the stator may be designed as a further insert, which ensures the torque support of the stator without a gap and robustly via a friction-locked and/or formfitting connection.
[0024] In one preferred refinement of the present invention, the stator housing section is designed as an outer housing section of the basic housing. In particular, mechanical interfaces may be situated on the stator housing section for fastening the basic housing to the vehicle. It is possible in this case that the interfaces are designed as plastic interfaces or that further fastening devices are embedded in the plastic. Optionally, mechanical interfaces may also additionally be formed in the stator carrier section and/or in the electronic housing section. In particular, advantages with respect to the corrosion behavior may be achieved in this refinement. Furthermore, it is possible to injection mold stiffening ribs or structures on the stator housing section or on the plastic part, to stabilize the composite and therefore make it lower-noise.
[0025] Another object of the present invention relates to a wheel hub motor for a vehicle, which has a basic housing as recited in one of the preceding claims. The wheel hub motor is particularly preferably designed as an internal rotor motor, the stator being situated in the radial interior of the stator housing section. Furthermore, the wheel hub motor has a rotor, the rotor being non-rotatably connected to a rim section of the wheel hub motor, a tire of the wheel being able to be situated on the rim.
[0026] In one preferred refinement of the present invention, the basic housing, in particular the stator carrier section, has a mechanical interface for fastening a brake back plate. Alternatively or additionally, the wheel hub motor includes an integrated brake device, which may be designed as a brake drum or brake disk device. In this case, the brake linings are situated on the brake back plate, which is non-rotatably connected via the mechanical interface to the basic housing. In contrast, the brake drum or the brake disk, respectively, is non-rotatably connected to the rotor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Further features, advantages, and effects of the present invention result from the following description of preferred exemplary embodiments of the present invention.
[0028] FIG. 1 shows a longitudinal sectional view of a wheel hub motor as an exemplary embodiment of the present invention;
[0029] FIG. 2 shows a basic housing of the wheel hub motor in FIG. 1 in a longitudinal sectional view in a first variant;
[0030] FIG. 3 shows the cooling device in FIG. 2 in a schematic three-dimensional view in a first variant;
[0031] FIG. 4 shows the cooling device in FIG. 2 in a schematic three-dimensional view in a second variant;
[0032] FIG. 5 shows the cooling device in FIG. 2 in a schematic three-dimensional view in a third variant;
[0033] FIG. 6 shows a basic housing of the wheel hub motor in FIG. 1 in a longitudinal sectional view in a second variant;
[0034] FIG. 7 shows a basic housing of the wheel hub motor in FIG. 1 in a longitudinal sectional illustration in a third variant;
[0035] FIG. 8 shows a schematic view of a cooling coil of the cooling devices in FIGS. 3, 4, and 5 .
DETAILED DESCRIPTION
[0036] FIG. 1 shows a longitudinal sectional view along a main axis 1 of a wheel hub motor 2 —also called a wheel hub system—for a vehicle 3 . The vehicle may be, for example, a passenger automobile, a wheel hub motor being situated on each of the two wheels of a driven axle. It is also possible, to implement a four-wheel-drive of a vehicle 3 by forming each of the wheels as a wheel hub motor 2 . Implementations in the form of a tricycle or a motorcycle are also possible, only one driven wheel being provided with wheel hub motor 2 in each case. Wheel hub motor 2 is optionally completely or at least sectionally situated in the radial interior of a tire 4 .
[0037] Wheel hub motor 2 has a basic housing 5 , which is situated in a frame-fixed or stationary way on vehicle 3 . Basic housing 5 carries a stator 6 . Furthermore, wheel hub motor 2 has a rotor carrier 7 , which carries a rotor 8 . Stator 6 and rotor 8 jointly form an electric motor 9 , which is designed as an internal rotor. Stator 6 is designed in the form of a hollow cylinder, which revolves around main axis 1 and is situated coaxially thereto. Rotor 8 is also designed as a hollow cylinder and is situated concentrically and coaxially in relation to stator 6 . Rotor carrier 7 is non-rotatably connected to rotor 8 and rotates in operation in relation to stator 6 and therefore in relation to basic housing 5 . Rotor carrier 7 is connected via a rim section 10 to tire 4 , so that an electrical drive torque of electric motor section 9 , which is generated with the aid of stator 6 and rotor 8 , may be transmitted via rotor carrier 7 and rim section 10 to tire 4 , to drive vehicle 3 . Stator 6 and rotor 8 are situated inside rim section 10 when viewed in the axial direction in relation to main axis of rotation 1 and do not protrude axially beyond it and/or beyond tire 4 .
[0038] Basic housing 5 may be divided into three sections, namely a stator housing section 11 , a stator carrier section 12 , and an electronics receiving section 13 . Stator housing section 11 is designed as a tubular or hollow-cylindrical section and encompasses main axis 1 completely in the circumferential direction. Stator housing section 11 is situated coaxially in relation to main axis 1 and to stator 6 . Stator 6 presses flatly against its inner circumferential wall or inner wall 25 , which is designed as a cylinder jacket surface, so that a heat transfer may take place from stator 6 to stator housing section 11 . Alternatively, one or more thermal coupling layers are situated between stator 6 and inner wall 25 . For example, stator 6 is located in an interior 14 , which is formed by stator housing section 11 on the radial interior of stator housing section 11 , in a press-fit in relation to inner wall 25 .
[0039] To dissipate the heat generated by electric motor section 9 , stator housing section 11 has cooling channels 15 , which extend, for example, at least sectionally in the circumferential direction around main axis 1 and are situated in multiple rows one over another in the axial direction in this example. With respect to a width B of stator 6 in the axial direction in relation to main axis 1 , at least 80% of width B is taken by cooling channels 15 .
[0040] Stator housing section 11 is attached to stator carrier section 12 , which extends in a radial plane in relation to main axis 1 and/or carries stator housing section 11 and bridges the installation space in the direction of main axis 1 as a disk section.
[0041] Electronics receiving section 13 , which—as results in particular from the following figures—is designed as one or more receiving structures, in which the power electronics and/or the control electronics and/or inverter devices are situated in completely assembled wheel hub motor 2 , is situated on the side of stator carrier section 12 facing away from stator housing section 11 . Electronics receiving section 13 is delimited on the bottom side by stator carrier section 12 or by a separate bottom of its own and has side walls 16 a, b extending in the axial direction on the edges.
[0042] A back plate interface 17 for an integrated brake device 18 is situated, in particular formed, on basic housing 5 . Back plate interface 17 is designed as a planar plate area in a radial plane in relation to main axis of rotation 1 , into which two receiving openings for fastening elements such as pins are introduced. A brake cylinder as brake device 18 , which presses brake shoes 19 outward in the radial direction against a brake drum 20 connected to rotor carrier 7 , may be situated on back plate interface 17 . Furthermore, basic housing 5 , in particular stator carrier section 12 , may have at least one mechanical support point 21 , which is designed for the sliding support of brake shoes 19 . Mechanical support point 21 is formed as a further planar plate area in a further radial plane in relation to main axis of rotation 1 . Mechanical support point 21 is optionally provided with a wear protection layer.
[0043] To enable a relative rotation between rotor carrier 7 and basic housing 5 , a wheel bearing 22 is provided, which is non-rotatably connected to basic housing 5 as a first bearing partner, on the one hand, and is non-rotatably connected to rotor carrier 7 as the other bearing partner, on the other hand. Basic housing 5 or stator carrier section 12 has a corresponding bearing interface 23 . With respect to bearing interface 23 , it is possible, on the one hand, that it is integrally incorporated, in particular formed in stator carrier section 12 . Alternatively, it is possible that stator carrier section 12 is connected to a separate bearing plate (not shown), which carries bearing interface 23 .
[0044] Basic housing 5 is designed as a multifunctional body. In the exemplary embodiment of the present invention shown in FIG. 1 , basic housing 5 is designed as a plastic housing. It may be provided that only stator housing section 11 is designed as a plastic part, but the manufacturing is simplified if stator housing section 11 and stator carrier section 12 or even optionally electronics receiving section 13 in addition are manufactured as a single plastic part. In this case, basic housing 5 may be produced in the scope of a plastic injection molding method in a single method step, for example.
[0045] FIG. 2 shows one possible design embodiment of basic housing 5 in FIG. 1 . It may be seen in the cross section shown that stator housing section 11 assumes a hollow-cylindrical shape, cooling channels 15 being situated in rows in an axial extension direction in the longitudinal section shown. Stator housing section 11 , stator carrier section 12 , and electronics receiving section 13 are formed as a one-piece plastic part. Cooling channels 15 are implemented by a cooling device 26 , which is embedded in basic housing 5 designed as a plastic part. Cooling device 26 is also coolant-tight even without the plastic part. Examples of cooling device 26 are described by way of example in FIGS. 3, 4, and 5 .
[0046] It is one concept of this implementation that the introduction of cooling channels 15 into the plastic part requires substantial expenditure. For this reason, in the present case an independent cooling device 26 is used, which is embedded as a separate and solely functional component in the plastic. In this way, on the one hand, the advantage of the cost-effective manufacturing of basic housing 5 designed as a plastic part and, on the other hand, a cost-effective implementation of cooling channels 15 may be achieved.
[0047] Cooling device 26 forms a further cooling channel 27 , which extends inside stator carrier section 12 and which cools electronics receiving section 13 . Cooling device 26 may have, for example, a cooling jacket section 28 , which is embedded in stator housing section 11 , and may have an inflow or outflow area 29 , which implements further cooling channel 27 . Stator 6 presses flatly with its radial outer surface in the form of a cylinder jacket on a contact surface 30 formed by stator housing section 11 , so that a heat transfer is promoted between stator 6 and cooling device 26 .
[0048] In the exemplary embodiment shown in FIG. 2 , stator 6 is embedded as a further insert in the plastic. In particular, cooling device 26 and stator 6 are jointly extrusion coated by the plastic. This embodiment has the advantage that stator 6 , being embedded in the plastic, in particular by extrusion coating using the plastic, is fixed in its position.
[0049] Cooling channels 15 or the cooling coils of cooling jacket section 28 have an oval cross section, one side of the cooling coils facing toward stator 6 being flattened. The heat transfer between stator 6 and cooling device 26 is improved by the surface enlargement as a result of the flattening. In the exemplary embodiment shown in FIG. 2 , it may be provided that cooling coils 31 rest in direct contact against stator 6 or are separated therefrom by a thin intermediate layer made of plastic or a plastic area, but are thermally coupled.
[0050] A further insert 32 in the form of a disk, for example, made of metal, is inserted in stator carrier section 12 , which enables an increase of the stability of stator carrier section 12 and therefore of basic housing 5 . Further insert 32 is also already embedded in the scope of the manufacturing process. A central section of the basic housing may optionally be formed as a next insert 34 . Next insert 34 may be formed from metal, for example, from steel. Next insert 34 may support, for example, back plate interface 17 , support point 21 , or bearing interface 23 . The advantage of next insert 34 as an extension of stator carrier section 12 is that in particular the attachment to wheel bearing 22 is made more rigid and more stable than in a plastic embodiment like the specific embodiment in FIG. 7 . This is because of, on the one hand, the material properties of metal, in particular steel, and, on the other hand, because metal is more aging-resistant than plastic and does not have a tendency to creep.
[0051] FIG. 3 shows a three-dimensional view of cooling device 26 . Cooling device 26 has cooling jacket section 28 , which is formed by 3 to 4 rows of cooling coils 31 , which wind around main axis of rotation 1 in particular in the form of a coiled spring or spiral. Inflow-outflow section 29 , which is formed by further lines, which are laid so that the desired areas of stator carrier section 12 and/or electronics receiving section 13 are cooled, is located on the side facing toward stator carrier section 12 . For example, inflow-outflow section 29 includes a cooling plate, which is located in a radial plane in relation to main axis of rotation 1 and which is designed to cool electronics. Cooling jacket section 28 forms a cylindrical interior.
[0052] FIG. 4 shows an alternative embodiment of cooling device 26 , cooling coils 31 being formed as rectangular lines, whose curvature is adapted to the curvature of contact surface 30 . Cooling coils 31 each extend meandering in the axial direction in this exemplary embodiment. A structure of cooling jacket section 28 is shown in FIG. 5 , cooling coils 31 being assembled into a network.
[0053] FIG. 6 shows another exemplary embodiment of the present invention, an annular gap being provided between contact surface 30 and the outer surface of stator 6 . In this exemplary embodiment, stator 6 is not embedded, but rather is installed later. A liquid component or potting compound may be introduced as a temperature coupling layer into intermediate gap 33 , so that the thermal transfer is optimized. Furthermore, the component or potting compound may implement a formfitting and/or friction-locked effect and mechanically secure stator 6 .
[0054] FIG. 7 shows another exemplary embodiment of the present invention for a basic housing 5 , in comparison to the exemplary embodiment in FIG. 2 , the middle part forming a partial section of stator carrier section 12 and therefore back plate interface 17 , support point 21 , or bearing interface 23 being integrally formed into the plastic part. It may optionally be provided that bushings, in particular steel bushings for reinforcement, are embedded in the plastic part.
[0055] FIG. 8 shows an altered specific embodiment of the cross section of cooling coils 31 , these having a conically tapering shape in the direction of contact surface 30 . This conically tapering shape has the advantage that the plastic may flow better into the area between contact surface 30 and cooling coils 31 .
LIST OF REFERENCE NUMERALS
[0000]
1 main axis
2 wheel hub motor
3 vehicle
4 tire
5 basic housing
6 stator
7 rotor carrier
8 rotor
9 electric motor
10 rim section
11 stator housing section
12 stator carrier section
13 electronics receiving section
14 interior
15 cooling channels
16 a, b side walls
17 back plate interface
18 brake device/brake cylinder
19 brake shoes
20 brake drum
21 mechanical support point for sliding support
22 wheel bearing
23 bearing interface
24 entry and exit openings
25 circumferential, cylindrical inner wall
26 cooling device
27 cooling channel
28 cooling jacket section
29 inflow or outflow area
30 contact surface
31 cooling coils
32 further insert
33 intermediate gap
34 next insert
B width
H main axis of rotation | A basic housing for a wheel hub motor, which can be produced cost-effectively even in large quantities is provided. To this end, a basic housing ( 5) for a wheel hub motor ( 2) is proposed, wherein the basic housing ( 5) has a receiving area ( 14) for a stator ( 6), having at least one stator housing section ( 11) for arranging the stator ( 6), wherein cooling channels ( 15) for cooling the stator ( 6) are arranged in the stator housing section ( 11), and having a cooling device ( 26), wherein the cooling device ( 26) forms the cooling channels ( 15), wherein the stator housing section ( 11) is made of a plastics material, and wherein the cooling device ( 26) is at least partially embedded as a first insert in the plastics material in the stator housing section ( 11). |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of Ser. No. 921,920 filed Oct. 22, 1986 now abandoned and a continuation-in-part of Ser. No. 135,416 filed Dec. 21, 1987, now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to corrosion inhibitors for use with aqueous brines.
In many oil wells and gas wells, it may be desirable to contain the formation pressure by employing a hydrostatic head. This may be needed during the squeezing of sand consolidation compositions, during perforation operations, during well shut-ins, during gravel packing, or the like. Many well servicing fluids, sometimes referred to as completion or packer fluids, have been employed. These include, for example, drilling muds, brines, water, oil, ZnBr 2 -CaBr 2 solutions, CaCl 2 , CaBr 2 or solutions and the like.
In recent years, deeper, high pressure and high temperature wells have resulted in a need for solids-free, well servicing fluids having higher densities than are currently available. This is particularly true of wells in the Gulf of Mexico (offshore Texas and Louisiana), where higher hydrostatic pressures often require well-servicing fluids having densities in excess of 15 pounds per gallon (ppg). The need for solids-free, higher density well-servicing fluids is met by brines which contain zinc salts, such as zinc halides.
High density brines and their preparations are set forth in U.S. Pat. No. 4,304,677 and U.S. Pat. No. 4,292,183. These zinc-containing brines have the disadvantage of being more corrosive than brines which are substantially free of zinc salts. Therefore, the high density brines, i.e., those brines having densities greater than about 14.5 ppg, are especially corrosive to oil well casings and equipment used in the service of said casings. The corrosion problem is exacerbated by the higher temperatures typically found in the deeper wells in which high density brines are used. Known corrosion inhibitors, such as film-forming amines, which have been used in high density brines do not provide adequate protection from corrosion at the higher temperatures associated with the deep wells in which high density brines typically are employed.
British Patent No. 2,027,686 is typical of the known technology in this area and discloses the use of sulfur compounds and quaternary pyridinium compounds as corrosion inhibitors.
It would therefore be desirable to develop a corrosion inhibitor which could provide increased protection for metals from corrosion caused by high density brines, especially by zinc salt containing high density brines at the higher temperatures found in deep wells.
SUMMARY OF THE INVENTION
The present invention provides high temperature corrosion protection for metals which come in contact with high density brines. The present invention is a composition which comprises:
A high density fluid useful for drilling wells with reduced metal corrosion which comprises:
(A) an aqueous solution of zinc bromide with or without zinc chloride and calcium bromide with or without calcium chloride having a density in the range from about 14.5 to about 21.0 pounds per gallon,
(B) 50 to 10,000 parts per million of a member of the group consisting of
(i) an aldehyde having the formula
R-(CH.sub.2).sub.m --(CH═CH).sub.n --CHO
where R is a radical selected from the group consisting of methyl, phenyl, tolyl, and nitrophenyl,
m is 0 to 7,
n is 0 or 1, with the proviso that when
n is 0, m is 0 to 5, and
(ii) the reaction product of an aldehyde having the formula
R--(CH.sub.2).sub.m --(CH═CH).sub.n --CHO
where R is a radical selected from the group consisting of methyl, phenyl, tolyl, and nitrophenyl,
m is 0 to 7
n is 0 or 1, with the proviso that when n is 0, m is 0 to 5, with a primary amine having the formula
R--(CH.sub.2).sub.n --NH.sub.2
where R is NH 2 , OH, CH 3 or phenyl and
n is a number from 2 to 6, and
(C) 250 to 10,000 parts per million of a thiocyanate salt selected from the group consisting of alkali metal thiocyanates and ammonium thiocyanate.
Surprisingly, the compositions of the present invention provide increased corrosion protection when employed with high density brines in deep well applications having temperatures exceeding about 250° F. (121° C.). Further, the present invention results unexpectedly in reduced pitting of metals contacted with a high density brine.
DETAILED DESCRIPTION OF THE INVENTION
The present invention may be employed to reduce the corrosive effects of high density brines upon metals. Metals which typically come in contact with high density brines include iron, steel, and other ferrous alloys, with steel being most common as it widely used in the oil and gas industries. The present invention is particularly effective in reducing the corrosion rate of steel which is contacted with high density brines.
The high density brines employed in the present invention include all brines which contain salts of zinc. It is possible to blend zinc salt-containing brines with lower density brines to obtain brines having densities less than about 14.5 pounds per gallon (ppg). However, the corrosion inhibitor of the present invention is particularly applicable to those brines having a density greater than about 14.5 ppg. Generally, the high density brines are aqueous solutions of certain halides of calcium and/or certain halides of zinc. See, e.g., U.S. Pat. No. 4,304,677 and U.S. Pat. No. 4,292,183 for references to high density brines and their preparation. These patents are incorporated herein by reference.
The soluble aldehyde compounds employed in the present invention inhibit the corrosive properties of high density brines toward metals, especially iron and steel. Typical aldehydes can be alkyl or aryl and those especially preferred are represented by the following formula.
R--(CH).sub.m --(CH═CH).sub.n --CHO
where R is methyl, phenyl, tolyl, or nitrophenyl, m is 0 to 7, n is 0 or 1, with the proviso that when n is 0, m is 0 to 5.
Examples of useful aldehydes are cinnamaldehyde, benzaldehyde, acetaldehyde, octylaldehyde, nonylaldehyde, crotonaldehyde, trans-2-hexenal, trans-2-octenal, trans-2-pentenal, trans-2-nonenal, tolualdehyde, and nitrobenzaldehyde.
The aldehyde compounds employed in the present invention may be used in high density brines either alone, as mixtures, as reaction products with amines or they may be used as herein described in any combination with a synergist.
For the purposes of the present invention the amines which may be reacted with the aldehyde compounds include primary amines having the formula
R--(CH.sub.2).sub.n --NH.sub.2
where R is NH 2 , OH, CH 3 or phenyl and n is a number from 2 to 6.
Illustrative examples of such amines are ethylamine, diamines such as ethylenediamine, aromatic amines such as aniline and alkanolamines such as monoethanolamine, diethanolamine, and the like with monoethanolamine being most preferred.
For the purposes of this invention, an effective amount of the aldehyde is in the range from 50 to 10,000 per million with the range from 100 to 5,000 being the preferred amount. The most preferred range is 150 to 2,000 parts per million. The aldehyde-amine reaction product is used in the amount from 250 to 10,000 parts per million and preferably 500 to 5,000 parts per million.
Thiocyanate compounds such as alkali metal thiocyanates or ammonium thiocyanates are used in the range from 250 to 10,000 parts per million. The preferred range is 500 to 5,000 parts per million.
SPECIFIC EMBODIMENTS
The following preparations and examples are given to illustrate the invention and should not be construed as limiting its scope.
Preparation of Trans-Cinnamaldehyde (TCA)/Monoethanolamine (MEA) Reaction Product
In a reactor, 500 gms (3.8 moles) of TCA was heated with 250 gms(4.1 moles) of MEA at 120° C. for 8-10 hours. The reaction can be seen to start upon mixing by a slight exotherm and darkening in color. By the end of the reaction period the product is dark brown and very viscous. For easier handling the product may be dissolved in alcohol or other suitable solvent.
Test Procedure 1. Clean metal coupons by sonicating in acetone for approximately 5 minutes and rinsing with fresh acetone, and then weigh them. N-80 steel coupons having a density of 8.53 g/cm and a surface area of 2.1 square inches were rinsed with acetone and then sandblasted prior to cleaning.
2. Place one coupon in each test sample, using 42 ml of test fluid. (The amount of fluid corresponds to 20 ml fluid/in surface area of coupon). The coupons were sealed in 4-ounce glass jars with Teflon lined caps lubricated with silicon grease for the 250° F. tests. Place in cylindrical Teflon holders in aging cells and pressurize to 150 psi with N 2 for 350° F. tests. Place test containers in oven at the proper temperature for the desired amount of time.
3. Remove containers from oven and allow to cool. Remove coupons, clean by sonicating in 1 N HCl inhibited with 500 ppm Dowell A120 until scale is removed (not to exceed 2 minutes), and weigh. Corrosion rate in mils per year (mpy) equals: ##EQU1##
Where:
M=change in mass of coupon (g)
D=density of coupon (g/cm 3 )
S.A.=surface area of coupon (in 2 )
T=length of exposure (days)
EXAMPLES 1-2
The above Test Procedure was conducted with various concentrations of inhibitors under the following heat conditions: 5 days @ 250° F. using a 19.55 pounds per gallon solution containing 58.6% ZnBr 2 -18.5% CaBr 2 . The results are shown in Table 1.
TABLE 1______________________________________ Inhibitor % Concentrat- Protection ion(s) Corrosion OverRun Inhibitor(s) (ppm) Rate (mpy) Control 1______________________________________Cntl 0 0 283Cntl TCA 1000 247 12.72Cntl TCA 2000 195 31.13Cntl TCA 4000 68 76.04Cntl TCA/MEA 1000 28 90.15 reaction productEx. 1 TCA/NH.sub.4 SCN 1000/1000 10 96.5Ex. 2 TCA/MEA 1000/1000 13 95.4 reaction product + NH.sub.4 SCN______________________________________
Table 1 shows that NH 4 SCN and trans cinnamaldehyde (TCA) when combined with MEA or TCA alone is highly effective as a corrosion inhibitor at 250° F.
EXAMPLES 3 AND 4
The above Test Procedure was repeated with various concentrations of inhibitors under the following test conditions: 5 days @ 350° F. using a 19.29 pounds per gallon solution containing 54.0% ZnBr 2 -18.9% CaBr 2 . The results are shown in Table 2.
TABLE 2______________________________________ Inhibitor % Concentrat- Protection ion(s) Corrosion OverRun Inhibitor(s) (ppm) Rate (mpy) Control 1______________________________________Cntl 0 0 258Cntl NH.sub.4 SCN 1000 251 2.77Cntl TCA/MEA 2000 241 6.68 reactionproduct.sup.(1)Ex. 3TCA/MEA 1000/1000 152 41.1reactionproduct.sup.(1)+NH.sub.4 SCN______________________________________ .sup.(1) Diluted 50:50 in isopropanol
Table 2 shows that even when the TCA/MEA reaction product-NH 4 SCN combination is diluted to a 50% solution, it still gives good protection from corrosion over the controls even at high temperatures such as 350° F.
EXAMPLE 4
The above Test Procedure was repeated with concentrations of various inhibitors under the following test conditions: 5 days @ 250° F. using a 19.2 pounds per gallon solution containing 54.0% ZnBr 2 -18.9% CaBr 2 . The results are shown in Table 3.
TABLE 3______________________________________ Inhibitor % Concentrat- Protection tion(s) Corrosion OverRun Inhibitor(s) (ppm) Rate (mpy) Control______________________________________Cntl 90 0 331 0Ex. 4TCA + NaSCN 176/990 28 91.5(1)______________________________________ (1)The inhibitor concentration included 110 ppm of Nmethylpyrrolidone as cosolvent to keep the TCA in the aqueous solution. | A high density brine useful as a drilling fluid for deep wells is rendered corrosion resistant by the incorporation of a soluble aliphatic or aromatic aldehyde with or without olefinic unsaturation and with the use of alkali metal thiocyanates or ammonium thiocyanates. The aldehyde can be reacted with a primary amine prior to use. |
CROSS-REFERENCE TO RELATED APPLICATIONS
This Patent Application claims the benefit of U.S. Provisional Application No. 60/138,368 filed Jun. 10, 1999, the contents of which are incorporated herein by reference in its entirety.
BACKGROUND
1. Technical Field
The present disclosure relates generally to the field of carcass processing, and particularly, is directed to an enhanced water disinfection process for use in the processing of a foodstuffs. More particularly, the disinfection process is designed as an intervention step in poultry processing to allow for continuous on-line processing of poultry carcasses that may have accidentally become contaminated during the evisceration process.
2. Background of the Related Art
The typical poultry processing plant receives live animals from the grow-out farms, slaughters the animals, drains the blood and then removes the feathers, “paws”, heads and eviscera in the initial stages of processing. The carcasses are thereafter sent by way of mechanized line operations through a series of washing, chilling and sanitizing steps before the product is shipped as “fresh” product or packaged for freezing. These line operations typically consume large quantities of water.
Accordingly, the poultry processing industry has generally been characterized as a large volume consumer of water in conducting the slaughter, processing, and packing of the animals for both human consumption and other uses. Recent initiatives by the United States Department of Agriculture (USDA), under the jurisdiction of the Food Safety Inspection Service (FSIS), have resulted in a further increase in the volume of water used to wash poultry carcasses in order to meet the more stringent requirements of zero (0) tolerance for visible fecal contamination. Furthermore, recent introduction of Hazardous Analysis and Critical Control Point (HACCP) programs provide for the transition of the inspection process from one heavily weighted by USDA oversight to a more self-regulated format wherein the poultry producer shoulders more of the inspection burden. As a consequence, there has been additional heightened awareness and recognition of the need for greater product safety, including the reduction of microbial contamination levels.
The poultry industry has been actively seeking intervention methods designed to meet the current USDA regulations for continuous on-line processing. These regulations deal with the corrective actions that are mandated to remove carcasses that have been contaminated during evisceration with digestive tract materials. The regulations require that these contaminated carcasses be removed from the main processing line and transferred to an approved reprocessing line where the contamination can be removed by washing, trimming, vacuuming or a combination of these steps.
Prior method disinfection and processing goals have been to act as an intervention step which allows for the continuous on-line processing of poultry carcasses using a single point treatment which utilizes either trisodium phosphate washing or acidified chlorite. In general, single point treatment of a rapidly moving carcass on a production line is insufficient to meet the complex food safety requirements in a poultry processing plant. The single point treatment system using trisodium phosphate washing is described in U.S. Pat. No. 5,882,253. In the case of trisodium phosphate, the process is further disadvantaged by the introduction to the plant's operations of increased levels of nutrients such as phosphates (i.e;, a byproduct of trisodium phosphate) that may need to be removed in the plant's wastewater operations due to environmental discharge regulations or concerns.
Such environmental discharge regulations and concerns require that poultry processing plants decrease the level of nutrients such as phosphates in wastewater discharge. Additionally, the application of trisodium phosphate elevates the pH of the carcass being processed, as well as the process water all of which carries over to the plant's chill system. The increased pH level in the chill system makes downstream chlorine disinfection less effective without significant chemical additions.
As discussed above and as dictated by the state of the art poultry or carcass processing plants, the current processes fail to appreciate the benefits associated with pH control, multiple point controlled treatment, or even the unexpected advantages to be gained by reducing the organic loads within such process water. By failing to appreciate these requirements, the conventional approaches commonly suffer from difficult treatment challenges and as a result, these approaches have been accompanied by disadvantageously high operating costs and reduced efficiency. This has in turn translated in to reduced product quality and reduced processing plant productivity.
SUMMARY
The various objects and aspects of the present invention are met using an approach which focuses on appropriately regulating and controlling the pH of the process water to be disinfected and through addition, regulation and control of a disinfecting agent. The control of pH and level of disinfecting agent is implemented throughout multiple steps in the production process including any process water to be recovered and reused. This is in contrast to prior approaches which have failed to appreciate the benefits associated with pH control, multiple point controlled treatment, or even the unexpected advantages to be gained by reducing the organic loads within such process water.
Advantages of the present invention comprise processes which allow for the automated regulation of the pH of poultry processing water, preferably at certain stages of the process, so as to dramatically improve the efficiency and effectiveness of antimicrobial or other disinfection agents added. The poultry process treatment water which can especially benefit includes the water used in poultry scalding, picking, post-pick washing, evisceration, carcass washing and other stages of poultry processing designed to physically remove any fecal matter, ingesta and other digestive tract remnants from the slaughter and evisceration processes. Additionally, an improved device and method are provided for effecting economic and efficient regulation of disinfection agent and control of the disinfection chemistry throughout the multiple steps of the production process.
Physical removal of visible fecal material and other contaminants from poultry carcasses will be carried out by serial carcass washing steps (e.g., scalder, picker, post pick spray wash, inside/outside carcass washing cabinets and outside carcass washing cabinets) where medium pressure, high volume water spraying is employed. The introduction of USDA approved antimicrobial agents (e.g., calcium hypochlorite or others), applied at optimum pH control level for chlorine disinfection at multiple treatment stages (e.g., scalder, picker, post pick spray wash, inside/outside carcass wash and outside carcass wash) and using the best practical control methods is designed to significantly reduce microbial levels on all carcasses prior to and after their entry into the submersion chiller system.
The invention described herein is designed to employ the advantages of controlled chlorination (e.g., calcium hypochlorite and/or other USDA approved food grade biocides) at optimum pH levels, together with the proven effectiveness of increased contact time (CT) through the implementation of multiple stage treatment of the carcass during slaughter, evisceration, washing and chilling.
Additionally, an improved device and method are provided for effecting economic and efficient regulation of disinfection agent effectiveness comprising a system and method for removing a major portion of filterable materials including fats, oils and greases (FOG), total suspended solids (TSS), proteins, blood products, lipids and other materials represented as total is chemical oxidation demand (COD) from the chiller tank water.
The presently disclosed disinfection process for use in the processing of foodstuffs is designed as an intervention step in poultry processing to allow for continuous on-line processing of poultry carcasses that may have accidentally become contaminated during the evisceration process. Such on-line processing is designed to replace the need for off-line manual washing and cleaning of the contaminated carcasses. By eliminating such off-line manual washing, food safety will be enhanced due to the elimination of the physical handling of carcasses and the cross-contamination that may result from such physical handling. An additional benefit is that it will be possible to run the production process with a reduced number of interruptions, which will result in a more efficient production process. The disinfection process according to the present invention, include: the removal, using the processing plant's existing washing, spraying and mechanical scrubbing devices (modified if required), of visible fecal material or other contaminants from the carcasses resulting from the mechanical evisceration process; the introduction of an enhanced antimicrobial treatment agent at multiple stages to improve food safety by reduction of total microbial levels; the improvement of disinfection in the facility's overall production process including the carcass chiller system through the use of pH controlled chlorination to further reduce microbial counts, and the reduction of the amount of physical handling of carcasses and therefore, reduction of the potential for cross-contamination.
Further, the present invention is specifically designed to be easily incorporated into the processor's existing production equipment and plant layout. This ease of implementation is accomplished by using, to the greatest extent possible, the processor's existing carcass wash stations, scalders, pickers and other designated treatment points as the point of treatment by using the existing water piping and delivery systems as the means of delivery of the invention's chemical and disinfection enhancements.
The invention described herein is designed to meet the current USDA regulations for removal of visible fecal material using the plant's existing washing, spraying and mechanical scrubbing devices, and to reduce microorganism counts and improve food safety, all in a more cost effective and environmentally friendly manner than other approaches.
An additional benefit of the invention relates to those poultry processors who have or who intend to implement water reuse programs. Such water reuse programs, as is the subject of U.S. application Ser. No. 09/507,163, filed Feb. 18, 2000 and which is hereby incorporated by reference in its entirety, have met with favorable and advantageous results by returning reuse water that has been disinfected with ozone and then chlorinated at an advantageous dosage before being reintroduced to the production process at an upstream point, such as in the scalder or similar heating portion of the processing steps. The reintroduction of the chlorinated reuse water into the scalder or similar heating processing step causes a dramatic reduction in the levels of microorganisms associated with the carcasses that have not been found in the prior art. Also, it is an embodiment of the present disclosure, to introduce chlorinated and/or ozonated water (or other approved disinfectant) along the foodstuffs processing steps, particularly along the points where the use of heated water is applicable, such as in the scalder or similar processing steps which subject the carcasses to heated water. In such heated processing steps, the pores and tissue membranes of the carcasses are open and are more readily receiving of the surrounding water, i.e., the chlorinated and/or ozonated water, thereby having greater efficacy to the removal of microorganisms associated with such foodstuff processing.
In view of the foregoing, the advantages of the present disclosure include providing new methods for improving the effectiveness of the disinfection agent being used, new methods for improving the decontamination of poultry or other foodstuff and the water used in the processing of said poultry and other foodstuff, and water reuse methods which cause a reduction in the levels of microorganisms associated with the carcasses.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and features of the present disclosure, which are believed to be novel, are set forth with particularity in the appended claims. The present disclosure, both as to its organization and manner of operation, together with further objectives and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, in which:
FIG. 1 depicts a flow chart of the multi-stage chlorination process and chiller treatment system according to the present disclosure;
FIG. 2A provides a more detailed flow plan of the multi-stage chlorination process of FIG. 1;
FIG. 2B provides a more detailed flow plan of the chiller treatment system of FIG. 1; and
FIG. 3 depicts an alternate view of the chiller treatment system according to the present disclosure.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The preferred embodiments of the apparatus and methods disclosed herein are discussed in terms of a disinfection process designed as an intervention step in poultry processing to allow for continuous on-line processing of poultry carcasses that may have accidentally become contaminated during the evisceration process. It is envisioned, however, that the disclosure is applicable to a wide variety of processes including, but not limited to, general carcass or foodstuffs processing including processing operations used in poultry, beef and pork slaughter plants.
As discussed throughout the present disclosure, the control of the pH of the treatment water within product processing water optimizes the elimination of pathogens and other microorganisms. Also, by providing an intervention step to allow for continuous on-line processing of poultry carcasses, there is a reduction in the amount of physical handling of carcasses and therefore, a reduction in the potential for cross-contamination of the carcasses, thereby improving quality and food safety. The present disclosure also discloses methods and devices for improving the effectiveness of disinfection agents in chiller tank processing water by substantial removal of filterable materials. A particular advantage is the fact that the methods of the present invention can be “retrofitted” to existing processing plants without any significant alteration of the plant's “footprint” or layout.
While the processes and devices described will be equally applicable to the aqueous processing of a variety of foodstuffs, for convenience, the application to the poultry processing industry will be described. This industry uses significant volumes of water in its processing operations. Much of the water used during such processing is regulated by the USDA, although the quantity and process steps vary from plant to plant. On average, the typical slaughter plant will use between 5 and 15 gallons per animal, divided into several key elements:
The Scalding process—USDA guidelines dictate a minimum of 1 quart per animal.
The Picking (de-feathering) process—varies from plant to plant.
The Evisceration process—varies from plant to plant.
Carcass washing (including Inside/Outside Carcass Washers, Intermediate Wash Stations and Final Rinse Cabinets)—these combined carcass wash steps can use between 2 and 6 gallons per animal.
The Chilling process (chillers)—USDA guidelines require minimum overflow rates of 0.5 gallons per animal in whole bird chiller tanks and temperature control. Various processors also utilize chilled water for “paws”, gizzards and other edible organs sold commercially. Typical chiller operations can consume between 0.75 and 1.5 gallons per animal.
Plant Sanitation—plant sanitation can use between 1.5 and 3 gallons per animal.
Equipment wash—a typical processing plant will use between 0.25 and 1 gallon per animal in equipment washing (this is an “on-line” process and should be differentiated from sanitation during which the entire plant and equipment is washed and sanitized when the plant is not in production).
Miscellaneous water usage—truck wash, live loading shed wash, domestic water, wastewater and industrial (non-product contact uses such as evaporative cooling for refrigeration, vacuum pump seal and cooling and compressor cooling) wash.
Most of the water is used during the evisceration and carcass washing steps and is typically applied by mechanical mechanisms comprising spray washing devices, cabinet type washers, brush washers and medium and/or high-pressure water spraying heads. The present invention takes advantage of the use of these existing water processing steps and mechanisms in improving the disinfection of the processing water and thus the processed foodstuff thereby improving its quality and safety.
Referring to FIGS. 1, 2 A and 2 B, the physical aspects of the present disclosure are illustrated as a common header 12 (either existing in the processing plant or, modification of the plant's water delivery system or, a custom, site built common header) used as the delivery mechanism to convey the treated water (e.g., calcium hypochlorite plus pH control) to the designated treatment points in the process. A tablet or liquid chlorine feed system 14 sized to deliver the maximum practical and allowable dosage of chlorine to the entire volume of water required to serve the multiple stages of treatment is situated along the common header 12 . Also situated is a gas/liquid or, liquid/liquid injection device 16 to permit the introduction of the preferred acidification agent (e.g., CO 2 , or other chemical agent) into the water in the delivery header to alter the levels of pH in the treatment water based on the readings of the pH probe 18 . A control panel 20 is used along the process in order to monitor the readings and control the dosages of the chemical agents required to perform the disinfection and pH control 22 . Multiple sensors 24 are located along the common header 12 in order to monitor, control the conveyance of the enhanced disinfection chemistry, measure chlorine levels and pH levels and send via electronic signal (feedback loops) the measurements to the proper chemical controllers.
The present disclosure makes use of (with or, without modifications) the plant's existing carcass wash cabinets and mechanical washing devices 26 to assist in the removal of visible contamination and serve as treatment points for the delivery of the enhanced disinfection chemistry. Devices for scalding, feather picking, post-pick washing and evisceration line washing stations act as additional treatment points for the delivery of the enhanced disinfection chemistry, as well as the plant's water recycle and reuse system 28 , where the water has been disinfected with ozone (ozonated) or other appropriate disinfectant and then dosed with an appropriate level of an approved disinfection agent (e.g., calcium hypochlorite or others) before being reintroduced into the production process at an upstream point, such as in the scalder or similar heating portion of the processing steps. An alternative to the disclosed water recovery and reuse system 28 is an ozonating or chlorinating system 29 which simply ozonates or chlorinates outside water and reintroduces such water to any or all of the heated processing steps, i.e. the scalder step, the picker step and the post-pick step, which utilize heated water (heated water being defined as water used during poultry processing which is or was heated at some point, preferably, but not limited to, at the scalder step). This reintroduction, like with the water recovery and reuse system 28 , reduces the levels of contamination within the poultry.
Multi-Stage, Controlled pH Chlorination During Poultry Processing
While the USDA mandates the use of a disinfection agent (typically chlorine) at various stages of the poultry processing operations, it is silent concerning the conditions under which the as disinfection agent is employed. It has been discovered that the effectiveness of the disinfection agent may be dramatically altered by characteristics of the processing water being treated, most notably pH, but also by the solute load presented by filterable materials. Other aspects of the present invention lie in the ability to improve the disinfection quality of the processing water at multiple points during processing. This becomes important because the effectiveness of a disinfection agent is directly proportional to the time in which the microorganisms to be killed are in contact therewith. The importance of contact time has been reflected in the US Environmental Protection Agency's (USEPA) Contact Time “CT” Values, in its guidelines concerning the disinfection of drinking water. These relationships have been perhaps most clearly spelled out by a mathematical formula developed by Chick in 1908, which described the kinetics of disinfection:
N t =N 0 exp (− kt )
Where:
N t =number of microorganisms surviving after time t
N 0 =initial number of microorganisms
−k=rate constant dependent upon type of microorganism and disinfectant
t=time the organisms is in contact with the disinfectant
USEPA CT Values are expressed as mg/L-min; where
mg/L=concentration of disinfectant
min=time in contact with disinfectant
Clearly then, the longer and/or more often that the microorganisms (whether in the water or on the poultry being processed) come into contact with the disinfectant, the greater the reduction of microorganisms and the safer the poultry.
However, it has been discovered that there are still other factors which must be considered, including those which affect the efficacy of the disinfection agent. Several of the embodiments of the present invention take advantage of methods of optimizing these factors, chief amongst which is pH. The temperature and pH level of the water into which the disinfection agent, e.g. chlorine, is introduced can dramatically affect the effectiveness of the disinfection agent. This is illustrated by Tables 1-7 shown below, which are published by the USEPA concerning guidelines to CT values (lower numbers mean higher antimicrobial efficacy) in drinking water. These tables show the dramatic improvement in effectiveness of chlorine and chlorine derivatives at both lower pH and higher temperature. The tables also demonstrate how different microorganisms react differently to disinfection agents, e.g., viruses require longer contact periods to be inactivated.
The methods of the present invention capitalize upon these effects by adjusting the pH of the processing water to levels between pH 5 and 8, most preferably between pH 6.5 and 7, and by bringing such pH controlled disinfecting water into contact with the carcasses at multiple processing points. While the level of hypochlorous acid will continue to increase as pH levels continue to decline (thereby resulting in greater anti-microbial activity), the resulting corrosive nature of liquids with severely depressed pH can have deleterious effects upon plant equipment, not to mention hazard to equipment operators and hence, such reduced pH levels do not represent the optimum practical levels. The inverse of this is also true.
TABLE 1
CT Values for 3-log (99.9%) Inactivation of Giardia Cysts
By Free Chlorine at Water Temperature 10.0° C. (50° F.)
Free Residual
pH
mg/L
≦6.0
6.5
7.0
7.5
8.0
8.5
≦9.0
≦0.4
73
88
104
125
149
177
209
0.6
75
90
107
128
153
183
218
0.8
78
92
110
131
158
189
226
1.0
79
94
112
134
162
195
234
1.2
80
95
114
137
168
200
240
1.4
82
98
116
140
170
206
247
1.6
83
99
119
144
174
211
253
1.8
88
101
122
147
179
215
259
2.0
87
104
124
150
182
221
265
2.2
89
105
127
153
186
225
271
2.4
90
107
129
157
190
230
276
2.6
92
110
131
160
194
234
281
2.8
93
111
134
163
197
239
287
3.0
95
113
137
166
201
243
292
TABLE 2
CT Values for Inactivation of Viruses By Free Chlorine
Log Inactivation
Temperature,
2.0-log
3.0-log
4.0-log
° C.
pH 6-9
pH 10
pH 6-9
pH 10
pH 6-9
pH 10
0.5
6
45
9
66
12
90
5
4
30
6
44
8
60
10
3
22
4
33
6
45
15
2
15
3
22
4
30
20
1
11
2
16
3
22
25
1
7
1
11
2
15
Note: CT values can be adjusted to other temperatures by doubling the CT for each 10° C. drop in temperature.
TABLE 3
CT Values for Inactivation of Giardia Cysts By Chloramine
Within the pH Range 6 to 9
Temperature, ° C.
Inactivation
≦1
5
10
15
20
25
0.5-log
635
365
310
250
185
125
1-log
1270
735
615
500
370
250
1.5-log
1900
1100
930
750
550
375
2-log
2535
1470
1230
1000
735
500
2.5-log
3170
1830
1540
1250
915
625
3-log
3800
2200
1850
1500
1100
750
TABLE 4
CT Values for Inactivation of Viruses By Chloramine*
Temperature, ° C.
Inactivation
≦1
5
10
15
20
25
2-log
1243
857
643
428
321
214
3-log
2063
1423
1067
712
534
356
4-log
2883
1988
1491
994
746
497
*This table applies for systems using combined chlorine where chlorine is added prior to ammonia in the treatment sequence.
TABLE 5
CT Values for Inactivation of Giardia Cysts By Chlorine Dioxide
Within the pH Range 6 to 9
Temperature, ° C.
Inactivation
≦1
5
10
15
20
25
0.5-log
10
4.3
4.0
3.2
2.5
2.0
1-log
21
8.7
7.7
6.3
5.0
3.7
1.5-log
32
13.0
12.0
10.0
7.5
5.5
2-log
42
17.0
15.0
13.0
10.0
7.3
2.5-log
52
22.0
19.0
16.0
13.0
9.0
3-log
63
26.0
23.0
19.0
15.0
11.0
TABLE 6
CT Values for Inactivation of Giardia Cysts By Chloride Dioxide
Within the pH Range 6 to 9
Temperature, ° C.
Inactivation
≦1
5
10
15
20
25
0.5-log
10
4.3
4.0
3.2
2.5
2.0
1-log
21
8.7
7.7
6.3
5.0
3.7
1.5-log
32
13.0
12.0
10.0
7.5
5.5
2-log
42
17.0
15.0
13.0
10.0
7.3
2.5-log
52
22.0
19.0
16.0
13.0
9.0
3-log
63
26.0
23.0
19.0
15.0
11.0
TABLE 7
CT Values for Inactivation of Viruses by Chorine Dioxide
Within the pH Range 6 to 9
Temperature, ° C.
Inactivation
≦1
5
10
15
20
25
2-log
8.4
5.6
4.2
2.8
2.1
1.4
3-log
25.6
17.1
12.8
8.6
6.4
4.3
4-log
50.1
33.4
25.1
16.7
12.5
8.4
Accordingly, the preferred methods of the present invention incorporate the introduction of chlorine, a chlorine derivative (a preferred disinfectant agent), ozone or other approved disinfectant at a controlled pH (adjusted appropriately for the disinfectant employed given the additional practical considerations previously described). The introduction of such disinfectant in a combined system of chlorine injection (or mixing) and acidification (using carbon dioxide, citric acid, lactic acid or any other acid compound(s) approved for contact with food products by the USDA) into solution of the feed water is used in the following processing stages: the Scalders, the Pickers, the Post pick washers, the Inside Carcass Washers, the Inside/Outside Carcass Washers, the Outside Carcass Washers, the Final Carcass Washers and any other practical stage where water is used to physically remove contamination.
Similarly, disinfection of the foodstuffs are realized from the production of “chloramines” during the “up stream” introduction of the treated reuse water into processes employing elevated water temperatures. According to the present disclosure, the water reuse system incorporated in a poultry processing plant does not remove significant levels of nitrogen or ammonia from the process water which, subsequent to the ozonating step, combines with added chlorine passing through the cascade process, i.e., the gathering of process water from a number of source points in the production line, thereby forming various “chloramines” which, in the environment of elevated temperatures, aides in the reduction of microorganisms in the foodstuffs.
The processes of the present invention take advantage of frequent surface and internal contact of the disinfectant with the carcass to increase microorganism lethality and the disinfectant remaining on the carcass external surface and internal surfaces to allow for additional time between the various process stages. Therefore, by beginning the treatment or disinfection process at earlier stages of poultry carcass processing, many advantages are realized.
First, introducing disinfectant at earlier stages results in inactivation (kill) of additional potentially pathogenic organisms not addressed in the current practices. The carcass will be at a higher temperature directly after the scalder stage and into the “post pick” stage. Higher carcass temperatures result in opening of the pores on the carcass skin and loosening of the skin from the muscle tissue. At these conditions, the disinfectant will contact surfaces and tissues that later become unavailable (e.g. closed) as the carcass temperature falls (especially in the chiller tanks).
Second, introduction of disinfectant during evisceration, the disinfectant will contact the surfaces of the carcass at the stage when potential contamination with fecal material or ingesta is most likely. Additionally, some residual disinfectant will be carried over to the next stage allowing for additional contact time.
Third, carcass washing with water treated with disinfectant, whether carried out in one stage or in multiple stages (various processors utilize different methods, washer designs and frequency of washers), will again allow for additional surface contact with the disinfectant at its highest efficiency (due to controlled pH).
Lastly, the entire process at these stages is also designed to reduce the contaminant (microorganism) load as the carcass is sent to the chillers. Any reduction in the organic loading prior to the carcass entry into the chiller tank will serve to reduce the risk of cross-contamination when the carcasses are immersed in a common tank (communal bath).
The following chart reflects an example of time “t” value potentials using Multi-Stage Chlorination (at controlled pH) during poultry processing:
Direct
Time
Cumulative
Stage
Contact Time
Between Stages
Time “t”
1.
Scalders
60-120
seconds
5-20
seconds
65-140
seconds
2.
Pickers
30-90
seconds
6-9
seconds
36-99
seconds
3.
Post Pick
5-15
seconds
5-10
seconds
10-25
seconds
Wash
4.
IOBW Wash
10-30
seconds
6-16
seconds
16-46
seconds
5.
Final wash
10-30
seconds
8-18
seconds
18-48
seconds
Total Time
2.4-6.0
minutes
Enhanced Disinfection of Carcasses in Poultry Chiller Tanks
In an alternative embodiment, there is incorporated some of the same disinfection enhancements, as previously described, i.e., introduction of the disinfectant at pH levels where the maximum “active” compound is present in the poultry chiller tanks. Current practices and USDA guidelines require chiller tanks to be monitored for chlorine residual or total chlorine. The concentrations and testing protocols required vary from plant to plant. Generally because there are no specific mandates for disinfection of chiller tanks, there tends to be no uniformity in approach. The processes of the present invention benefit from utilization of an equipment package designed to continuously monitor and adjust the introduction of acidification to control pH level in the chiller tank as to allow for the maximum potential effective formation of hypochlorous acid (in those circumstances where chlorine is used) to enhance the disinfection process.
Similar practical considerations apply with respect to heat and the disinfection process. The invention is advantageously designed to utilize the elevation in water temperature at the scalding stage of the slaughter process. In poultry scalders, as well as the poultry picker and post-pick steps, the temperature of the water (and hence the poultry contained therein) is elevated to between 140 degrees F. and 170 degrees F. At these temperatures, the animal's skin releases from the muscle tissue and allows the aqueous chlorination to contact a larger surface area of the carcass. Also, the elevated temperature results in a higher reaction rate of chlorine reaction. Accordingly, the methods of the present invention, which provide controlled dosing of a disinfection agent, ideally will apply beginning with those processing steps which follow the initial slaughter steps.
With reference to FIGS. 2A and 2B, an advantage of the present invention includes the employment of a chiller tank water quality enhancement process. This process is ideally designed to continuously remove “filterable materials” from the chiller tank including FOG, TSS and COD. Disinfection is commonly affected by an oxidation process where the oxidant (e.g., hypochlorous acid, hypobromous acid, chlorine dioxide, ozone, hydrogen peroxide etc.) is the active disinfection agent. Since the oxidative reaction by the oxidation agent in water is a non-preferential one, the presence of high organic loading will pose a correspondingly higher oxidant demand to achieve comparable inactivation of microorganisms. To improve efficiency, the present inventive methods remove organics such as FOG, TSS and COD from the water to permit use of a lower disinfectant dosage to achieve the desired disinfection standard or “kill efficiency.”
These methods can ideally be practiced with the preferred devices of the present invention which comprise mechanism(s) for continuous “mass load” organic removal. This is ideally accomplished by the use of mass removal by floatation, screening or other suitable means, followed by fine filtration using Diatomaceous Earth (DE) filters, membranes or other suitable methods of removing the identified “filterable” materials. It has been discovered that this will enhance the chiller tank's water quality, reduce significantly the disinfectant demand and greatly increase the efficiency of employing disinfection at this critical stage of the process.
The ideal process utilizes an equipment package designed to continuously monitor and adjust the introduction of acidification to control pH in the chiller tanks, and allows for the maximum potential effective formation of hypochlorous acid (where chlorine is used) to enhance the disinfection process. As previously described, the chiller water treatment equipment consists of similar equipment packages.
Using the USEPA CT values, this stage represents the highest potential for disinfection enhancement. This is due to the length of time the carcass is immersed in the chiller bath (typically between 1.5 and 3.0 hours). Assuming a disinfectant dosage that will result in 5.0 ppm “free residual”, the resulting CT credit equates to 450-900 mg/L-min.
While the description of the present invention focuses on the use of some form of chlorine as the disinfection agent, it is important to note that other disinfection agents may be advantageously applied at one or more steps in the process. Disinfection agents such as chlorine dioxide, ozone, chlorites, etc., may be used to increase the effectiveness of the process.
In addition, the methods for improving disinfection processes may be advantageously combined with improved methods of water recovery and re-use within the processing plant (see, for example, U.S. application Ser. No. 09/507,163, filed Feb. 18, 2000, and previously made part of this disclosure by incorporation). Under such an approach, process water will be taken from the processing operations, filtered and disinfected to levels determined by the USDA. In such a system and following filtration, the filtered water is pumped by a centrifugal, end suction, top discharge pump to a disinfection system. Disinfection of the water is accomplished by the introduction of gaseous ozone into the filtered water. Ozone is generated by a corona discharge type ozone machine using cryogenic oxygen or, oxygen separated by pressure swing adsorption on-site as the parent gas. The ozone is preferably introduced into the filtered water by way of a venturi type gas/liquid mixing device (Mazzei Injector). The ozonated water is pumped through a pressure dwell manifold or a high efficiency, centrifugal gas/liquid-mixing device to promote maximum dissolution of the ozone gas. The ozonated water flows to an ozone contact tank (304 stainless steel) ideally sized to achieve a minimum of about 7 to 10 minutes of contact time. Ozone generator sizing is based on USEPA criteria for 3 to 4-log removal efficiency at an applied dose of a maximum of 7 ppm and a standard of 5 ppm. The ozone contact tank is fitted with either a dissolved ozone measuring device or an Oxidation-Reduction Potential (ORP) probe. This probe is interfaced with the dissolved ozone monitor or the ORP monitor in the system's main control panel, and dissolved ozone level or ORP is constantly displayed on the panel front. ORP and/or dissolved ozone is ideally controlled to achieve the desired disinfection standard determined by microbiological analysis at various dissolved ozone or ORP set points to assure that the water is pathogen free. A 750-mv set point is commonly used to indicate the sterility of water. The International Bottled Water Association (IBWA) and others indicate that, at this level of oxidation, the water is deemed sterile by drinking water standards and that microbiological activity is eliminated. An alarm is activated if ORP falls below the programmed setpoint and the system can be shut down. Following disinfection by ozonation, the water is rechlorinated at an advantageous dosage before being returned to the scalder or other heating processing steps.
As can be seen from FIGS. 1 and 2B, the apparatus for employing the embodiments of the enhanced disinfection of carcasses in poultry chiller tanks 30 includes the following primary components: the disinfectant distribution system 32 , pH control system 34 including acid control 40 , on-line monitoring 36 , organic mass removal system 38 (filtration for chiller tanks), a water reuse system 28 , and/or an ozonating or chlorinating system 29 .
The disinfectant distribution system 32 is designed to introduce, through direct injection into the process stream, the desired disinfectant. This sub-component may be advantageously configured for liquid/liquid injection and mixing, gas/liquid injection and/or solid dissolution followed by liquid/liquid injection. There are several common forms of disinfectant currently employed by the processing industry, including sodium hypochlorite, calcium hypochlorite, chlorine dioxide, ozone and others. It will be readily appreciated by those skilled in the art that each of these disinfectants will require a slightly different means of introduction into the process water stream.
The pH control system 34 is dependent upon the level of pH and the disinfectant employed. For sodium hypochlorite and calcium hypochlorite, the pH control system will preferably involve the introduction of acidification compound at a controlled and monitored rate. The rate of introduction (whether liquid/liquid or gas/liquid) will be monitored and proportionally controlled by the use of a PID or PLC type device to ensure that the pH level is controlled within a tight control band (i.e., for chlorine compounds 6.5-7.0 pH). On line monitoring allows for continuous monitoring of the treatment water by the use of pH probes 36 installed in the piping and distribution system. This assures that the pH level is at the desired “optimum” for the disinfectant employed.
An organic mass removal system 38 (filtration for chiller tanks) incorporates one or more steps designed to remove by physical separation, the organic contamination being constantly introduced to the carcass chiller tank(s) 30 . Each animal carcass will have some materials that have not been removed in prior washing. These materials include soluble and insoluble fats, oils, skin, blood products and other contaminants as previously described. The filtration system 38 is designed to remove either all or a major portion of these “filterable solids” in order to reduce the oxidant demand in the chiller tank 30 and thus permit reaching a higher disinfection standard.
As an essential step in the poultry processing system, the chilling process includes vessels into which the poultry carcasses are introduced from the plant's processing lines to reduce temperature of the meat, control bacterial growth through chemical disinfection and hydrate the carcass within the USDA limits of acceptable water content. The process described herein is directed at maintaining the best conditions for chemical disinfection in poultry chiller tanks. As background for such processes, the U.S. poultry industry employs immersion chilling for poultry, carcasses through the use of large volume, stainless steel tanks where the product is mechanically introduced from the processing line(s) after evisceration and inspection.
With reference to FIGS. 2B and 3, such poultry chillers 30 are connected to refrigeration loops, referred to in the industry as a “red water chiller(s),” for the purpose of rejecting heat from chilled water systems. Typically, these red water chiller recirculating systems 42 are closed loop heat exchangers operating with ammonia gas as the refrigerant and electric drive motors to provide the compression/expansion or state change of the refrigerant. The refrigeration chiller 42 typically operates as a closed recirculating loop, where the chiller acts as the heat exchanger to remove heat from the system water in order to maintain the USDA mandated temperature in the chiller tanks.
A mass removal system 38 is designed to continuously remove organic and solids content from the plant's chiller tanks 30 using screening, floatation, filtration and oxidation. The carcasses entering the chiller tanks 30 bring “contaminants” which may be of an organic or inorganic nature and consist of fats, oils, grease, blood products, proteins, lipids and pieces of skin and organs that may have remained after the evisceration. Other inorganic contaminants typically consist of minerals dissolved into the water such as phosphates, nitrogen compounds and other constituents originating in the animal feed or the water used in washing and chilling. The chiller tanks 30 are filled before the first processing shift and are constantly refreshed with potable water during the plant's processing hours (the USDA maintains a requirement of one-half (½) gallon of makeup water per bird). The entering makeup water replaces a similar volume of chiller tank overflow being dispensed from the tank 30 . This enables a refreshing of the chiller tank 30 to counteract the cumulative effects of concentration of the contamination brought into the tanks 30 with the carcasses.
It is known that the cumulative effects of constant introduction of the contaminants does negatively impact the effectiveness of carcass disinfection and microbial control. When analyzed for contaminant content, the water from chiller tanks 30 shows that there is a significant level of organic compounds that compete chemically with the microbial content for oxidizer demand. As such, most processing plants have had difficulties in controlling chlorine levels due to the presence of high organic loading.
The carcasses will typically remain in the chiller tanks 30 for between 45 minutes and several hours. The dwell time will be determined by the carcass weight, number of carcasses and efficiency of the chiller system in terms of refrigeration capacity. The controlling factor is the time required to achieve the temperature set by the USDA. The relatively long dwell times should provide an excellent opportunity for microbial control based on the previously described principals of contact time (CT). The limiting factor, however, is overcoming the organic loading resulting from the constant contaminant influx.
As discussed earlier, the process developed according to the present disclosure is directed at providing a continuous, on-line contaminant removal mechanism. The process is effected by the installation of mechanical separation, floatation and filtration devices 38 which are designed to remove organic compounds from the chiller tanks 30 . This mass removal of the organic compounds is accompanied by the implementation of enhanced disinfection/microbial control using the most favorable chemistry for chlorination 32 , 34 , 40 . The chemistry, as previously described herein, consists of the combination of pH control 34 and chlorine or other disinfectant injection 32 .
The continuous separation, floatation, filtration mechanism 38 for mass removal of the contaminants being introduced into the chilled water tanks 30 is connected to the chiller tank 30 by way of interconnecting piping where a constant volume of water is pumped from the chiller tanks 30 , sent to the contaminant removal apparatus, cleansed and returned to the chiller tanks 30 . The process is designed to operate continuously. Maintenance of chiller tank water quality is dictated by the disinfection efficiency as measured by the chlorine monitoring devices.
With particular reference to FIG. 3, the chiller tank treatment system process is designed to allow for maximum flexibility of operations based upon the site-specific conditions, load profile and economics. The observed range of chiller system water quality varies significantly across the spectrum of poultry processing plants. In some cases, the operation of the chiller system, together with the size, weight and process rate of birds, will allow a solution that may not require the same mass removal of contaminants as others. A time weighted load factor should be analyzed to assist with the sizing and specification of the components and overall system configuration. This procedure can be accomplished by taking numerous samples of the bulk water in the chiller tanks 30 over a specified period of time. A plot of the contaminant loading will yield a load per hour rate or a load per carcass rate that is important to the sizing and configuration of the treatment solution. A target water quality is established based on the disinfection chemistry and a treatment system is sized to remove the required mass load of contaminants to consistently maintain the target water quality.
The first stage of the system involves pumping water from the chiller tanks 30 , by way of a dedicated pump 70 to the treatment system's first stage unit operations. This stage includes a mechanical screening device 72 such as a double drum rotating type, where the influent water is introduced into the internal portion of the device. The double drum screen includes a larger mesh screen as its internal first stage, and a smaller mesh as its external second stage. As the solids are captured on either the internal or external screen surfaces, a traveling, high-pressure water spray nozzle, directed at the surface of the screen, forcibly removes the trapped solids and enhance the screen's ability to maintain flow capacities. The screened water is captured by gravity in a sump located below the screens. The sump is fitted with level sensors to interface with a pump fitted to the sump to allow for automatic operation and to prevent the pump from “dry cycling” when no water is available to pump.
The screened water, now having the preponderance of large solids removed, is pumped to the system's floatation unit 74 . This floatation unit 74 could be either of the induced or dissolved air type. Selection of the best method is based on site-specific load characteristics and the targeted mass removal efficiency. Air floatation is well-documented in the literature and operates on well-understood principles of vertical bubble velocity and the ability to attract solids and colloidal materials. Simple skimming and/or overflow removes the floated material. Typical floatation devices are easily adaptable to accept chemical assistance in the form of coagulants, flocculants and other treatment chemicals designed to enhance removal efficiencies. The use of any such chemical assistance would be subject to FDA and USDA regulations and guidelines relating to food quality and safety.
The now screened and floatation treated water is then flowed to the filtration device 76 which removes smaller solids. The selection of the filtration device 76 , such as a media filter, will depend upon site-specific conditions. The media filter can use diatomaceous earth as its media and the filter vessel could be of a vacuum leaf, rotating vacuum drum, or pressure leaf design. The smaller solids not removed by the previous stages (screening and floatation) are trapped on the media filter's media matrix which, in the case of diatomaceous earth, has removal efficiencies capable of treating to small micron size particles. The effluent quality from such devices is quite high and is typically below 5 NTU's in turbidity. The treated water is now ready to be transferred back to the chiller tanks 30 . At any point along the above identified filtration steps 38 , the treated water can be monitored for turbidity via a monitoring device which allows the operator to monitor the system performance. Such a monitoring device can be installed anywhere in-line with alarms, feedback loops or recording devices, which enables total system performance and provides a base for implementing modifications.
It will be readily understood by those skilled in the art that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be so construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. | The presently disclosed disinfection process for use in the processing of foodstuffs is designed as an intervention step in poultry processing to allow for continuous on-line processing of poultry carcasses that may have accidentally become contaminated during the evisceration process. Such on-line processing is designed to replace the need for off-line manual washing and cleaning of the contaminated carcasses. By eliminating such off-line manual washing, food safety will be enhanced due to the elimination of the physical handling of carcasses and the cross-contamination that may result from such physical handling. An additional benefit is that the production process will also be able to run with a reduced number of interruptions, which will result in a more efficient production process. The invention described herein is designed to employ the advantages of controlled chlorination at optimum pH levels, together with the proven effectiveness of increased contact time through the implementation of multiple stage treatment of the carcasses during slaughter, evisceration, washing and chilling. Additionally, an improved device and method are provided for effecting economic and efficient regulation of disinfection agent effectiveness, comprising a system and method for removing a major portion of filterable materials, represented as total chemical oxidation demand from the chiller tank water. |
BACKGROUND OF THE INVENTION
Swing check valves are currently available for installation into large pipelines 24 inches in diameter and larger. One such check valve is shown in U.S. Pat. No. 3,897,804. The valve body is formed of spherical configuration, and separately formed cylindrical hubs, one of which carries a seat ring, are welded into body openings. The valve clapper is hinged to the valve body so as to swing down into closed position and seat firmly against the seat ring. However, attaining the accurate relationship between the clapper shaft center line and the sealing face between the seat and the clapper, in order to insure proper seating, requires extremely tedious and accurate machine work while handling a heavy, bulky and unwieldy member, i.e. the complete valve body.
OBJECTS OF THE INVENTION
It is an object of this invention to provide a method of mounting a clapper in a swing check valve that does not require handling the complete valve body.
It is a further object of this invention to provide a swing check valve with a clapper which is easily and precisely mounted with respect to the valve seat.
Other objects and advantages of this invention will become apparent from the description to follow, particularly when read in conjunction with the accompanying drawings.
BRIEF SUMMARY OF THE INVENTION
In carrying out this invention, the swing check valve is provided with a clapper, which in closed position seats firmly against a seat ring carried on a hub member welded into the valve body around a flow passage. The clapper is pivoted, not on the valve body, but on the hub member which carries the seat ring, and the positioning of the valve shaft is accomplished with the seat hub separate and apart from the valve body. After, proper adjustments are made, the valve clapper and the seat hub are inserted in the body and the seat hub is welded in place.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a vertical section view of a swing check valve including an embodiment of this invention;
FIG. 2 is a partial vertical section view of a swing check valve including another embodiment of this invention;
FIG. 3 is a section view taken along line 3--3 of FIG. 2.
DESCRIPTION OF PREFERRED EMBODIMENTS
The Embodiment of FIG. 1
Referring now to FIG. 1 with greater particularity, the swing check valve 10 of this invention includes a spherical main body section 12 which may be fabricated from hemispherical sections, which are formed from steel plates or the like and welded together at 14 along a vertical great circle. The hemispherical sections are formed with upstream and downstream openings 16 and 18 which may be swaged outward to form hubs 20 and 22 of the ultimate pipeline diameter. The hubs 20 and 22 are finished at their ends 20a and 22a for welding into a pipeline, but is to be understood that they may be provided with flanges or otherwise prepared for pipeline installation. Suitable legs 24 may be welded to the spherical body 12 to support the valve erectly, particularly during manufacturing and shipping.
A seat hub 26 is welded into the upstream hub 20 and an annular recess 28 is formed in the inner end thereof in order to accommodate a seat ring 30. The seat ring 30 is secured in place by set screws 32 and an O-ring 34 is provided to seal around the outer surface. A resilient seal ring such as an O-ring 36 is also provided as the main seal for sealing engagement with a clapper 38.
The clapper 38 is preferably of spherical, dished configuration with a substantially radial outer border 40 that seats against the seat ring 30 when the clapper is in its closed position, as shown. The clapper may be reinforced with a disc 42, which is welded across the concave portion thereof, the disc being provided with openings 44 to balance fluid pressure across it.
A cylindrical hub or boss 46 is welded to the back of the clapper 38 and slidably receives the clapper arm 48 which is keyed to a shaft 50. The shaft 50, in turn, is rotatable in a complementary fixed hinge member 52, which is welded at 54 directly to the seat hub 26. A retainer ring 56 is welded to the boss 46 to limit the amount of play of the clapper 38 on the arm 48, but allows enough movement to enable the clapper 38 to accommodate itself to the seat ring 30 and seat firmly thereagainst. A stop 58 at the lower end of the arm 48 engages the interior surface of the body 12 to define the full-open position of the clapper, as shown in phantom.
A partial sleeve 60, which is mounted on legs 62 embraces the clapper 38 and extends across the spherical body 12 to improve flow characteristics and facilitate the passage of pigs and the like, as disclosed in U.S. Pat. No. 3,897,804.
In order to facilitate the introduction and assembly of the clapper 38 and to enable seat replacement, an opening 64 is provided in the top of the spherical body 12, and this is closed by a dome 66 reinforced by a disc 68 and bolted at 70 to a vertical cylindrical flange 72.
Since the fixed hinge 52 is welded directly to the seat hub 26, it is not necessary to handle the complete valve body 12 while the clapper is being mounted. In fact, the clapper 12 may be mounted, and the fixed hinge 52 welded to the hub 26, entirely apart from the valve body 12 and then the hub 26 and clapper 38 may be inserted through the opening 64 as a unit and welded in place.
After checking to ensure that the seat/clapper assembly and shaft fit nicely together, they are disassembled and the seat hub 26 is welded into the body shell 12. Where the shaft 50 is provided merely to suspend the clapper and does not extend outside of the body 12 for selective operation, it may also be practical to assemble the seat, clapper and shaft after the seat hub has been welded in place, but before the body shells 12 have been welded together at 14.
The Embodiment of FIGS. 2 and 3
In describing this embodiment, components which are substantially unchanged from the embodiment of FIG. 1 will bear the same numbers; substitutes and corresponding components will bear the same numbers with a hundreds digit added. Hence, the seat hub 126 is recessed at 128 at its inner end to receive a seat ring 130, which is secured to the end of the seat hub 126 by means of cap screws 132. As in the first embodiment, O-rings 134 and 136 are provided to seal around the seat ring 130 and to engage with the clapper 138. In this embodiment, the fixed hinge component 152 is positioned precisely and welded to the seat ring 130 apart from the valve body and prior to finishing either part. Then, the seat faces and O-ring grooves are machined and, using the seat face as a reference, the hinge pin hole is bored. Finally, the shaft is removed; the seat ring 130 is inserted through the opening 64 and bolted in place; and then the clapper is again positioned and the shaft 150 replaced. This may be done before the body shells 12 are welded together at 14.
The clapper 138 may be operated from outside the valve by rotating the shaft 150 with the wrench or the like applied at the end 74, the shaft being keyed to the clapper at 153. A sleeve 76 extends into the valve body 12 and is welded in place to freely accommodate the shaft 150 and outer bearing collar 80 rotatably receives the outer end of the shaft 150 as provided with a bushing 82 and a suitable seal ring 84. A flange 86 on the collar 80 is secured by a clamping ring 88, as by tightening bolts 90, carried in the plate 92 and threaded into the sleeve flange 78. Hence, the clapper assembly 138, 148 is bolted in place with the seat ring 130, with the shaft 150 extending freely through the sleeve 76. Because of the free fit, no adjustment with respect to the complete valve body 12 is required. Whatever position it assumes, the bearing collar 80 is clamped in place by tightening the screws 90.
While this invention has been described in conjunction with preferred embodiments thereof, it is obvious that modifications and changes therein may be made by those skilled in the art without departing from the spirit and scope of this invention, as defined by the claims appended hereto. | A pipeline swing check valve comprising a fabricated valve body with a fabricated cylindrical hub member welded therein. The clapper is hinged, not to the body, but directly to the hub member or some part thereon so that it can be mounted and adjusted for proper seating without handling the entire valve, and then installed with the hub member as a unit. |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the field of light emitting diode drive circuits.
[0003] 2. Prior Art
[0004] Light emitting diodes are used in many applications to light displays or buttons, such as on cell phones, pagers, computers, etc. In such applications, it is desirable to have a constant illumination when using one or multiple diodes. The brightness of a light emitting diode depends upon the current flowing through the diode. Diodes are conventionally biased through a series resistor from a regulated voltage supply. The problem associated with this technique is that the amount of current through the diode depends significantly upon the forward voltage drop of the diode, which varies with size, process, temperature and aging. The present invention is directed to methods and apparatus for providing a predetermined current to such diodes in spite of these variations.
BRIEF SUMMARY OF THE INVENTION
[0005] Current source methods and apparatus for light emitting diodes providing constant diode current and illumination in the presence of voltage and process variations. The method comprises providing a predetermined current through a first transistor, and mirroring the current through the first transistor to at least one additional transistor while holding the voltage across the first transistor to a predetermined value, wherein each additional transistor is coupled in series with a light emitting diode. An exemplary circuit, as well as various illustrative applications are disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] [0006]FIG. 1 is a diagram of an exemplary embodiment of the present invention
[0007] [0007]FIG. 2 is a diagram showing first exemplary application of the present invention.
[0008] [0008]FIG. 3 is a diagram showing second exemplary application of the present invention.
[0009] [0009]FIG. 4 is a diagram showing third exemplary application of the present invention.
[0010] [0010]FIG. 5 is a diagram showing fourth exemplary application of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] The present invention current source methods and apparatus for light emitting diodes is ideally suited for use in battery operated systems, particularly those using white light emitting diodes used for lighting buttons, displays and the like on hand held, laptop and similar devices. Consequently for purposes of illustration and not for purposes of limitation, the exemplary embodiments of the invention are described in a manner consistent with such use, though clearly the invention is not so limited.
[0012] Now referring to FIG. 1, a diagram of an exemplary embodiment of the present invention may be seen. The embodiment shown is intended for fabrication in integrated circuit form for driving up to three light emitting diodes LED 1 , LED 2 and LED 3 . The integrated circuit includes an enable (EN) pin, a SET pin, LED connection pins OUT 1 , OUT 2 and OUT 3 and an integrated circuit ground GND.
[0013] In the exemplary embodiment, the integrated circuit itself requires very little power, and accordingly, power for the circuit is provided by the enable signal on the enable pin EN. When the voltage on the enable pin EN goes high (typically to the system battery voltage or approaching the system battery voltage), the reference voltage generator Vref provides a reference voltage to an amplifier A 1 , in the specific exemplary embodiment shown, a 1.25 volt reference voltage. In the event, however, that the enable signal on the enable pin EN is below a predetermined voltage, namely a predetermined voltage below which the circuit is to be operated, an undervoltage lockout circuit UVLO will detect the undervoltage condition and disable the voltage reference generator Vref.
[0014] The positive input to amplifier A 1 is taken from the drain of transistor Q 1 which is connected to an external control voltage Vctrl through a user selectable external resistor Rset. Amplifier A 1 , therefore, drives the voltage on the gate of transistor Q 1 to a level such that the drain voltage of transistor Q 1 equals the output of the reference voltage generator Vref, in the specific exemplary embodiment being described, 1.25 volts. Thus the effect of the amplifier is to hold the voltage across transistor Q 1 , source to drain, to a predetermined voltage, 1.25 volts in the exemplary embodiment. This is to be compared to simply using a current mirror to mirror a current through a resistor coupled to an external regulated voltage to the transistors coupled to the LEDs. With such a current mirror alone, the resistor current and thus the LED current, as well as the LED drive transistor headroom, would be highly dependent on the threshold of the transistors, which has a substantial processing variation.
[0015] Since amplifier A 1 has a very high input impedance, the drain current of transistor Q 1 will be equal to Rset{overscore (Vctrl−Vref)}. In a typical application, the control voltage Vctrl may use an existing regulated power supply elsewhere in the system in which the present invention is being used.
[0016] The output of amplifier A 1 is also used to drive the gates of transistors Q 2 , Q 3 and Q 4 . These transistors are preferably substantially larger than transistor Q 1 , transistor Q 1 only being used to establish the gate voltage for transistors Q 2 , Q 3 and Q 4 , while these latter transistors are each sized to conduct the LED current of the LED connected thereto. In the preferred embodiment, transistors Q 2 , Q 3 and Q 4 are approximately 200 times the size of transistor Q 1 . Thus the current through transistor Q 1 is mirrored to each of transistors Q 2 , Q 3 and Q 4 in a ratio of 200:1, at least for those devices to which an LED is connected. In that regard, while the exemplary embodiment may be used to drive three LEDs, any lesser number may be used, as any transistor having an open drain will neither draw power nor otherwise affect the operation of the rest of the circuit. The circuit of FIG. 1 further includes a thermal shutdown circuit of a type well known in the prior art, which will shutdown the circuit to turn off transistors Q 2 through Q 4 in the event the circuit is subject to an excessive temperature, internally generated or otherwise.
[0017] When the voltage on the enable pin EN is low, the integrated circuit is disabled and transistors Q 1 through Q 4 are turned off, providing a high impedance on the terminals SET, OUT 1 , OUT 2 and OUT 3 , allowing any external circuitry connected thereto to pull the respective pin high without power dissipation.
[0018] In a typical application, the LEDs are supplied and turned on and off by a regulated charge pump, such as the MAX682/3/4, manufactured by Maxim Integrated Products, Inc., the assignee of the present invention. Also, the preferred embodiments of the present invention are used with white LEDs. Due to the typically high forward conduction voltage of white LEDs, the charge pump is used to provide enough voltage headroom such that the LEDs will maintain constant brightness for any battery voltage. When the charge pump is on, the LEDs are on, and when the charge pump is off, the LEDs are off. The charge pump's regulated output may also be used as the control voltage Vctrl. The use of the MAX682/3/4, which is a 3.3 volt input to a regulated 5 volt output charge pump, is exemplary only, and presented only as an illustration of one application of the present invention. Such an application is shown in FIG. 2. In a typical application, the MAX682/3/4 would also be supplying other circuits in the system. Preferably at least a 4 volt to 5.5 volt regulated supply is used in order to provide enough voltage headroom such that the LEDs will maintain constant brightness for any battery voltage.
[0019] An alternate application of the present invention may be seen in FIG. 3. This application is substantially the same as in FIG. 2, though with the enable pin EN is brought out separately for control independent of the presence of the 5 volt output of the MAX682/3/4.
[0020] For a particularly low cost application, the LEDs may be supplied directly from a battery, such as either a single lithium ion cell or three NiMH (nickel metal halide) cells, as shown in FIG. 4. Due to the typically high forward voltage of white LEDs, the LED brightness may slightly dim at the end of battery life. However, the present invention's current regulated architecture and low dropout will greatly minimize this effect compared to using a simple ballast resistor for each LED. A regulated supply, typically already existing in the system in which the present invention is used, such as from an LDO, is used in this application to provide the control voltage Vctrl.
[0021] [0021]FIG. 5 illustrates a further alternate application of an exemplary embodiment of the present invention wherein a voltage output digital-to-analog converter (DAC) is used to provide the control voltage Vctrl such that the LED brightness may be factory calibrated, or dynamically adjusted in the field. Alternatively, a current output DAC may be used in order to eliminate the current setting resistor Rset. In this application, the LEDs may be supplied directly from the battery (single lithium ion or three NiMH cells) or from a regulated supply. As shown, the LEDs may be turned on and off using the enable pin EN rather than using the DAC in order to minimize supply current and leakage for longer battery life.
[0022] There has been disclosed herein a method and apparatus for biasing of a light emitting diode, such as but not limited to, a white diode with a current source such that the current through the diode and its brightness are significantly less dependent upon the forward voltage drop of the diode than in prior art circuits. While a specific exemplary embodiment and various exemplary applications of that embodiment have been disclosed, such disclosure has been for purposes of illustration only and not by way of limitation. Accordingly, while these specific embodiments have been disclosed in detail herein, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the following claims, giving the full scope thereto. | Current source methods and apparatus for light emitting diodes providing constant diode current and illumination in the presence of voltage and process variations. The method comprises providing a predetermined current through a first transistor, and mirroring the current through the first transistor to at least one additional transistor while holding the voltage across the first transistor to a predetermined value, wherein each additional transistor is coupled in series with a light emitting diode. An exemplary circuit, as well as various illustrative applications are disclosed. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims priority under 35 USC 119 from Japanese Patent Application No. 010-071874, filed Mar. 26, 2010.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a function providing apparatus and a computer readable medium.
[0004] 2. Related Art
[0005] In an apparatus (e.g., printer) which is configured by using a computer, an operating system (OS) is read from a hard disk drive (HDD) or the like into a memory and initialized by a processor upon power-on, whereby the function (e.g., printing function) of the apparatus is provided under the control of the OS.
SUMMARY OF THE INVENTION
[0006] According to an aspect of the invention, a function providing apparatus includes a first reading unit, a second reading unit, a first initializing unit, a second initializing unit, a first receiving unit, a second receiving unit, and a control unit. The first reading unit reads a first control program relating to a first function which is provided by using a particular device into a memory which serves as a work area of a processor. The second reading unit reads a second control program relating to a second function which is provided by data processing without using the particular device into the memory. The first initializing unit causes the processor to initialize the first control program stored in the memory. The second initializing unit causes the processor to initialize the second control program stored in the memory. The first receiving unit receives a first instruction to supply power to a given section that is used to operate the first reading unit, the second reading unit, and the second initializing unit. The second receiving unit receives a second instruction to make a transition to an ordinary state in which power is supplied to the function providing apparatus including the particular device. The control unit performs controls so as to cause the first reading unit to read the first control program and cause the second reading unit and the second initializing unit to read and initialize the second control program, respectively, in response to reception of the first instruction by the first receiving unit, then establish a power saving state in which supply of power to the memory is continued, and make a transition from the power saving state to the ordinary state to render the second function executable in response to reception of the second instruction by the second receiving unit in the power saving state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Exemplary embodiments of the invention will be described in detail based on the following figures, wherein:
[0008] FIG. 1 is a functional block diagram of a function providing apparatus according to an exemplary embodiment of the present invention;
[0009] FIG. 2 illustrates example activation processing of the function providing apparatus according to the exemplary embodiment of the invention;
[0010] FIG. 3 shows an example state transition diagram of the function providing apparatus according to the exemplary embodiment of the invention;
[0011] FIG. 4 shows an example configuration of main hardware of the function providing apparatus according to the exemplary embodiment of the invention;
[0012] FIG. 5 illustrates example activation processing of a conventional function providing apparatus (single OS); and
[0013] FIG. 6 illustrates example activation processing of another conventional function providing apparatus (multi-OS).
DETAILED DESCRIPTION
[0014] An exemplary embodiment of the present invention will be hereinafter described with reference to the drawings.
[0015] Although a multifunction machine having multiple functions of scanning, printing, copying, etc. will be described below as an example function providing apparatus according to the exemplary embodiment of the invention, the invention is not limited to such a case.
[0016] FIG. 1 is a functional block diagram of the function providing apparatus according to the exemplary embodiment of the invention. The function providing apparatus is equipped with a main power switch 11 and an auxiliary power switch 12 to be manipulated for switching the state of power supply to individual sections of the apparatus, an activation control section 16 for switching the state of power supply to the individual sections of the apparatus and performing a control so that activation processing is performed stepwise in response to switching of the main power switch 11 or the auxiliary power switch 12 , and other sections.
[0017] The details of control of the activation control section 16 will be described below. In response to turning-on of the main power switch 11 , the activation control section 13 supplies power to at least sections that are necessary for the activation processing of the apparatus and causes them to perform part of the activation processing. The activation control section 16 then makes a transition to a power saving state. In response to turning-on of the auxiliary power switch 12 in the power saving state, the activation control section 16 makes a transition to an ordinary state in which power is supplied to the entire apparatus.
[0018] As described above, in the function providing apparatus according to the exemplary embodiment, an instruction to supply power to at least the sections that are necessary for the activation processing of the apparatus is received by the main power switch 11 . An instruction to make a transition to the ordinary state in which power is supplied to the entire apparatus is received by the auxiliary power switch 12 . The activation processing is performed stepwise according to those instructions.
[0019] The activation processing is divided into loading processing of reading an OD (example control program) etc. from a control program storage unit 13 into a memory 14 which serves as a work area of a processor such as a CPU (central processing unit) and initialization processing in which the processor initializes the OS that has been read into the memory 14 . A loading processing section 17 performs the loading processing and an initialization processing section 18 performs the initialization processing.
[0020] Although in the exemplary embodiment the control program storage unit 13 is an HDD, it may be another form of nonvolatile storage device such as a ROM (read-only memory) or an SD (registered trademark) card. Although in the exemplary embodiment the memory 14 is a DRAM (dynamic random access memory), it may be another form of volatile storage device.
[0021] The functions provided by the function providing apparatus according to the exemplary embodiment include not only functions that are provided by peripheral devices 15 such as a scanner (image reading device) and a printer (image forming device) but also functions that are provided through data processing on electronic data that is stored in a storage unit (e.g., confidential box; not shown) incorporated in the apparatus.
[0022] The former functions are functions each of which requires a particular device for its execution, such as a scanning function of storing, in the apparatus or an external storage unit, electronic data of a sheet surface image obtained by reading a paper medium with a scanner, a printing function of forming a print image on a paper medium with a printer on the basis of electronic data received from an external terminal together with a print instruction and outputting the paper medium, and a copying function of forming, on another paper medium, with the printer, a sheet surface image obtained by reading a paper medium with the scanner and outputting the paper medium.
[0023] The latter functions are functions each of which does not require a particular device for its execution, such as a file transfer function of transferring, to a specified address, an electronic file (a unit of handling of electronized information such as electronic data of a sheet surface image obtained by the scanning function in advance) stored in a storage unit (e.g., confidential box) incorporated in the apparatus, a file format conversion function of converting the format of an electronic file (e.g., into the JPEG format or the PDF format), and a file combining function of combining plural electronic files into a single electronic file.
[0024] Having two OSs, the function providing apparatus according to the exemplary embodiment causes the former functions (i.e., the functions that require particular devices) and the latter functions (i.e., the functions that do not require particular devices) to operate on the different OSs. In the following the OS as an execution environment of the former functions will be referred to as OS 1 and the OS as an execution environment of the latter functions will be referred to as OS 2 . Although in the exemplary embodiment one OS 1 and one OS 2 are provided, plural OS 1 's and plural OS 2 's may be provided.
[0025] The OS 2 used in the exemplary embodiment has a menu function for calling not only a function that operates on the OS 2 but also a function that operates on the OS 1 . This menu function makes it possible to call a function corresponding to a user instruction received through the menu picture being displayed on a display device such as a liquid crystal panel. Therefore, to enable execution of a function that operates on the OS 1 , it is necessary that the initialization processing for the OS 2 be completed and the menu function be in operation.
[0026] A description will now be made of the activation processing of the function providing apparatus according to the exemplary embodiment.
[0027] In the function providing apparatus according to the exemplary embodiment, the following operations are performed under the control of the activation control section 16 in response switching of the main power switch 11 and the auxiliary power switch 12 .
[0028] When the main power switch 11 is turned on, the supply of part (e.g., 5 V) of voltages is started and power is supplied to at least sections that are necessary for execution of the activation processing (loading processing and initialization processing) of the apparatus. Examples of such sections are the CPU, boot ROM, DRAM, HDD, Ethernet (registered trademark) device, and SD card device. They are energized upon turning-on of the main power switch 11 . In the exemplary embodiment, whether an SD card is inserted or not is detected. And an exclusive control is performed for power-on of the nonvolatile memories. For example, if an SD card is inserted, the SD card device is powered on but the HDD is not. If no SD card is inserted, the HDD is powered on but the SD card device is not.
[0029] Then, the loading processing section 17 reads the OS 1 and the OS 2 from the control program storage unit 13 into the memory 14 , and the initialization processing section 18 causes the processor to initialize the OS 2 that has been read into the memory 14 . That is, the OS 1 is subjected to up to loading processing but not subjected to initialization processing. On the other hand, not only loading processing but also initialization processing is performed for the OS 2 . Then, a halt state is established.
[0030] Upon completion of up to the OS 2 initialization processing, a transition is made to a power saving state. And turning-on of the auxiliary power switch 12 is set as a condition (trigger) for recovery from the power saving state.
[0031] In the power saving state of the exemplary embodiment, only the memory 14 (DRAM) is energized, that is, continues to be supplied with power whereas no power is supplied to the other sections. Alternatively, part of the other sections may continue to be supplied with the same power or power that is lower than in the ordinary state. That is, the power saving state may be such that at least the memory 14 continues to be supplied with power and the supplied power is made lower than in the ordinary state in which the entire apparatus (including the peripheral devices 15 ) is supplied with power. In such a power saving state, the memory 14 being energized is self-refreshed and hence its storage contents (data of the OS 1 which is in the loaded state and data of the OS 2 which is in the loaded and initialized state) continue to be held.
[0032] When the auxiliary power switch 12 is turned on in the power saving state, a transition is made from the power saving state to the ordinary state, whereupon the entire apparatus (including the peripheral devices 15 ) comes to be supplied with power. And the OS 2 is subjected to resume processing for recovering it from the suspended state, whereby a state that such functions as the file transfer, the file format conversion, and the file combining are executable is established quickly. On the other hand, the OS 1 is subjected to initialization processing and, parallel with that, the peripheral devices 15 such as the scanner and the printer are subjected to initialization processing. As a result, a state that such functions as scanning, printing, and copying can be performed is established. In the exemplary embodiment, the OS 1 is configured so as to inform the OS 2 of completion of initialization of each function upon the completion so that the functions are rendered executable in order of completion of their initialization.
[0033] The initialization processing for the peripheral devices 15 can be of any of various types. For example, control programs for the respective peripheral devices 15 (or corresponding functions) may be run independently of the initialization processing for the OS 1 or control programs for the respective peripheral devices 15 (or corresponding functions) may be run on the OS 1 for which the initialization processing has completed.
[0034] In the function providing apparatus according to the exemplary embodiment, when part of the activation processing (loading processing for the OS 1 and loading processing and initialization processing for the OS 2 ) is performed in response to turning-on of the main power switch 11 , a transition is made to the power saving state after execution of the part of the activation processing if the auxiliary power switch 12 is not turned on. On the other hand, if the auxiliary power switch 12 is turned on, the ordinary state is maintained (no transition is made to the power saving state) after execution of the part of the activation processing. Therefore, in a case that the auxiliary power switch 12 is turned on during execution of the part of the activation processing which was started in response to turning-on of the main power switch 11 , such functions as the file transfer, the file format conversion, and the file combining are rendered executable soon after the execution of the part of the activation processing. Furthermore, the remaining part of the initialization processing (initialization processing for the OS 1 and initialization processing for the peripheral devices 15 ) is executed immediately, whereby such functions as scanning, printing, and copying are also rendered executable.
[0035] Next, the time that is taken until the individual functions are rendered executable in the function providing apparatus according to the exemplary embodiment will be described in such a manner that it will be compared with the time taken in a conventional apparatus.
[0036] FIG. 5 illustrates example activation processing of a conventional function providing apparatus which is a multifunction machine having a single OS.
[0037] In this example, up to OS loading processing is performed in response to turning-on of a main power switch. Then, the apparatus stands by until turning-on of an auxiliary power switch. OS initialization processing is performed in response to turning-on of the auxiliary power switch and, parallel with that, initialization processing for peripheral devices such as a scanner and a printer is performed. Such functions (services) as scanning, printing, and copying are rendered executable only after completion of both of the OS initialization processing and the peripheral devices initialization processing. That is, when the user turns on the auxiliary power switch to use the function providing apparatus, a waiting time occurs that lasts until completion of all the pieces of initialization processing.
[0038] FIG. 6 illustrates example activation processing of another conventional function providing apparatus which is a multifunction machine having plural OSs (multi-OS). As in the case of the exemplary embodiment, it is assumed that an OS 2 has a menu function for calling not only a function that operates on the OS 2 but also a function that operates on an OS 1 , and that to enable execution of a function that operates on the OS 1 it is necessary that initialization processing for the OS 2 be completed and the menu function be in operation.
[0039] In this example, up to OS 1 loading processing and OS 2 loading processing are performed in response to turning-on of a main power switch. Then, the apparatus stands by until turning-on of an auxiliary power switch. OS 1 initialization processing and OS 2 initialization processing are performed in response to turning-on of the auxiliary power switch. Parallel with those pieces of initialization processing, initialization processing for peripheral devices such as a scanner and a printer is performed. Such functions (services) as scanning, printing, and copying are rendered executable only after completion of all of the OS 1 initialization processing, OS 2 initialization processing, and the peripheral devices initialization processing. That is, when the user turns on the auxiliary power switch to use the function providing apparatus, even if the OS 1 initialization processing and the peripheral devices initialization processing have already completed, a function that operates on the OS 1 cannot be called successfully until completion of the initialization of the OS 2 on which the menu function for calling such a function operates. Therefore, a waiting time occurs that lasts until completion of all the pieces of initialization processing.
[0040] In contrast, in the function providing apparatus according to the exemplary embodiment, the activation processing is performed on the order shown in FIG. 2 .
[0041] Up to OS 1 loading processing, OS 2 loading processing, and OS 2 initialization processing are performed in response to turning-on of the main power switch 11 . Then, the apparatus stands by (denoted by symbol S 3 in FIG. 2 ) until turning-on of an auxiliary power switch. Resume processing is performed for the OS 2 in response to turning-on of the auxiliary power switch 12 , whereby a state that such functions as the file transfer, the file format conversion, and the file combining is established. On the other hand, OS 1 initialization processing is performed and, parallel with that, initialization processing for the peripheral devices 15 such as the scanner and the printer is performed. Such functions as scanning, printing, and copying are sequentially rendered executable as the respective pieces of initialization processing for the peripheral devices 15 are completed.
[0042] Since the peripheral devices 15 (particular devices) such as the scanner and the printer are not used under the OS 2 , the OS 2 initialization processing can be performed even in a state that the peripheral devices 15 are powered off (i.e., the auxiliary power switch 12 is off). Therefore, the OS 2 initialization processing can be completed after turning-on of the main power switch 11 (irrespective of the state of the auxiliary power switch 12 ).
[0043] In the example of FIG. 2 , a state that such functions (file services) as the filter transfer, the file format conversion, and the file combining are executable is established first. Then, a state that the scanning function which is provided by using the scanner is executable is established. Finally, a state that the printing function (printing service) and the copying function (copying service) which are provided by using the printer are also executable (i.e., a state that all the services can be provided) is established.
[0044] FIG. 3 shows an example state transition diagram of the function providing apparatus according to the exemplary embodiment.
[0045] At the beginning, the function providing apparatus according to the exemplary embodiment is in an off state 31 . When the main power switch 11 is turned on, a transition is made to an ordinary state 3 via a halt state 32 . In the ordinary state, power is not supplied to the entire apparatus but to only the sections that are necessary for execution of its activation processing (loading processing and initialization processing). Up to OS 1 loading processing, OS 2 loading processing, and OS 2 initialization processing are performed in this state. Then, a transition is automatically made to a power saving state 34 (except in the case where the auxiliary power switch 12 has already been turned on). When the auxiliary power switch 12 is turned on, a transition is made from the power saving state 34 to the ordinary state 33 and power is supplied to the entire apparatus. As soon as the functions to operate on the OS 2 are rendered executable, OS 1 initialization processing and initialization processing for the peripheral devices 15 are performed. Upon completion of those pieces of processing, the functions to operate on the OS 1 are rendered executable.
[0046] FIG. 4 shows an example configuration of main hardware of a computer that operates as the function providing apparatus according to the exemplary embodiment.
[0047] In this example, the computer has such hardware resources as a CPU 41 which performs various kinds of computation, main storage devices such as a RAM 42 which serves as a work area of the CPU 41 and a ROM 43 which is stored with fundamental control programs, an auxiliary storage device 44 (e.g., a nonvolatile memory such as the magnetic disk of an HDD or the like, an SD card, or a flash memory) which is stored with a program according to the exemplary embodiment of the invention and various data, an input/output I/F 45 which is an interface with a display device for displaying various kinds of information and input devices such as manipulation buttons and a touch panel to be used for an input manipulation by an operator, and a communication I/F 46 which is an interface for performing a wired or wireless communication with another apparatus.
[0048] Programs according to the exemplary embodiment of the invention are read from the auxiliary storage device 44 or the like, developed in the RAM 42 , and run by the CPU 41 , whereby the function providing apparatus according to the exemplary embodiment of the invention is implemented on the computer.
[0049] For example, the programs according to the exemplary embodiment of the invention are set in the computer in such a manner that it is read from an external storage medium such as a CD-ROM or received over a communication line.
[0050] The invention is not limited to the case of the exemplary embodiment in which the function providing apparatus is implemented by software. An equivalent function providing apparatus may be implemented by using dedicated hardware modules.
[0051] The foregoing description of the exemplary embodiment of the present invention has been provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and various will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling other skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. | A function providing apparatus includes a first reading unit, a second reading unit, a first initializing unit, a second initializing unit, a first receiving unit, a second receiving unit, and a control unit. The first reading unit reads a first control program relating to a first function provided by a particular device. The second reading unit reads a second control program relating to a second function provided by data processing without using the particular device. The first initializing unit causes the processor to initialize the first control program. The second initializing unit causes the processor to initialize the second control program. The first receiving unit receives a first instruction. The second receiving unit receives a second instruction. The control unit establishes a power saving state in which power is supplied to the memory is continued, and makes a transition from the power saving state to the ordinary state. |
BACKGROUND OF THE INVENTION
The subject invention concerns an engraving head for engraving gravure or intaglio printing cylinders and other pinting devices and also a sensing stylus sleeve structure and collet for use in such an engraving head.
Electronically controlled mechanical engraving machines, some of which have become known under their trade name "Klischograph," are used for engraving intaglio or rotogravure cylinders. They include an engraving head, or typically several engraving heads located side by side in parallel to a longitudinal axis of the printing cylinder.
Each engraving head has an engraving stylus and a sensing organ or stylus mounted on a common fixture. That fixture can be placed at the printing cylinder for applying the sensing organ or stylus at a predetermined pressure to the printing cylinder surface.
Up and down movement of the engraving stylus is generated by a control signal derived from an image signal produced by scanning a master. A raster signal which determines raster width is superimposed on the image signal. The continuously oscillating engraving stylus cuts into the surface of the gravure or intaglio cylinder pursuant to that control signal, so that raster cells or wells are cut which vary in depth and cross-section or cell volume in accordance with tone value.
Prints made with printing cylinders engraved by such known methods have shown a striated pattern consisting of stripes of differing color values.
As seen relative to the printing cylinder, these stripes extend in the longitudinal axis thereof. In Eurpose, this phenomenon has become known as "Jalousieeffekt"; that is, a "venetian blind effect." This kind of striated pattern effect is caused by periodically occurring unevenness of the cylinder surface or deviations from the geometrically exact cylinder form, which affect the cutting and thereby the formation of the raster cells.
SUMMARY OF THE INVENTION
It is an object of the subject invention to provide an improved engraving head and other devices of the type herein mentioned, by means of which the degrading effects of unevenness of the printing cylinder surface are effectively avoided.
The subject invention is based on the recognition that the scanning or sensing organ, applied to the printing cylinder at a certain pressure and following unevenness of the cylinder surface, is put into oscillations which are transmitted to the mounting fixture which thereby is excited into natural or self-oscillations. The oscillations of the mounting fixture, in turn, are transmitted to the engraving tool or stylus, whereby the controlled oscillatory movements thereof are influenced or affected. This, in turn, affects the engraving process and the shaping of the raster cells or wells.
According to the main aspect of the subject invention, an engraving head for apparatus for engraving printing cylinders, comprises, in combination, a drivable engraving tool, a sensing organ contacting any printing cylinder being engraved by the drivable engraving tool, means for effecting a firm and accurate guidance of the drivable engraving tool by the sensing organ contacting the printing cylinder, including a common mounting fixture for the drivable engraving tool and the sensing organ, and damping means between the sensing organ and the engraving tool for at least substantially barring transmission of oscillations from the sensing organ to the engraving tool, while preserving said firm and accurate guidance of the drivable engraving tool by the sensing organ contacting the printing cylinder. In this combination, the sensing organ includes a sensing stylus, an inner sleeve for retaining the sensing stylus, and an outer sleeve for mounting the inner sleeve and the sensing stylus in the common mounting fixture, and the damping means include an elastically deformable, energy absorbent element between the inner and outer sleeves.
By provision of such damping means in the stated combination, which at least largely suppresses or in effect prevents transmission of oscillations of the sensing organ to the mounting fixture and thereby to the engraving tool, that engraving tool is decoupled from the sensing organ so that surface inaccuracies of the printing cylinder, which would excite the sensing organ to oscillation, no longer are able to affect the engraving process.
The invention also may be stated in terms of a system or method, wherein a drivable engraving tool and a sensing organ contacting any printing cylinder being engraved by the drivable engraving tool are mounted on a common fixture, and objectionable striation patterns in prints made with such printing cylinders are avoided by locating a damping element between the sensing organ and the engraving tool for at least substantially barring transmission of oscillations from the sensing organ to the engraving stylus, while preserving a firm and accurate guidance of the drivable engraving tool by the sensing organ contacting the printing cylinder.
It is thereby important that the damping arrangement absorb oscillations of the sensing organ completely or at least to a material extent, since oscillations of the sensing organ can otherwise still transmit themselves to the mounting fixture, even if at a reduced frequency. Embodiments of the invention herein disclosed may be employed for that purpose to advantage.
In this respect, or according to a related apsect of the invention, a damping sleeve structure for mounting a sensing stylus relative to a fixture, comprises, in combination, an inner sleeve for receiving the sensing stylus, an outer sleeve insertable into a bore in that fixture, and an element between these inner and outer sleeves for at least substantially barring transmission of oscillations from the sensing stylus to that fixture.
Also according to a related aspect of the invention, a device for securing a damped sensing stylus mounting sleeve structure in a bore of a fixture, comprises, in combination, a collet receivable in that bore coaxially with the sleeve structure, and having an inside diameter leaving a circular interspace between the sensing stylus and the collet, and damping means received in a circular slot inside the collet and extending to the sensing stylus for preventing transmission of oscillations from the sensing stylus to the fixture.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention and preferred embodiments thereof are explained with the aid of the accompanying drawings, in which:
FIG. 1 is a schematic perspective view of a known engraving head for an electronically controlled engraving machine;
FIG. 2 is another view of the known engraving head as approximately seen in the direction of arrow A in Fig. 1;
FIG. 3 is a sectional plan view of the known engraving head approximately taken on the line III--III in FIG. 2;
FIG. 4 is a view similar to a detail view of FIG. 3, but showing on an enlarged scale a damping structure combination according to a preferred embodiment of the invention; and
FIGS. 5 and 6 illustrate variations within the scope of the subject invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
The illustrated engraving head 1 may, for instance, be used in electronically controlled mechanical engraving machines, such as those known under their trade name of "Klischograph."
That engraving head has a carriage 2 supporting a fixture 3. The carriage 2 is movable in the direction of arrow B and is guided by means of a conventional guide (not shown). The fixture 3 is connected to the carriage 2 by leaf springs 4, which are attached to the carriage 2 and to the fixture 3 by fasteners 5 and 6, respectively, shown only diagrammatically. The fixture 3 is thus tiltable in a well-known manner about an axis extending at right angles to the direction of movement of the carriage 2.
An elongate sensing organ or stylus 7 is held in the fixture 3 and has a tip 7a projecting therefrom. An engraving stylus 8 is mounted on the fixture 3 next to the sensing stylus 7 and has a cutting tip 8a. The engraving stylus 8 performs angular movements about an axis 9 in a manner known per se and therefore not illustrated in detail.
As seen in FIGS. 1 to 3, the fixture 3, through displacement of the carriage 2 in the direction of arrow B and tilting about the tilt axis determined by leaf springs 4, is moved toward the intaglio printing cylinder 10 to be engraved, until the sensing stylus 7 with its tip 7a contacts the printing cylinder 10 on its surface 10a at a specific pressure. As seen in FIG. 3, which shows the conventional known manner of mounting the sensing stylus 7, the fixture 3 has a through-bore 11 extending from back to front of that fixture for a mounting of the sensing stylus 7 extending therethrough.
A taper sleeve 12, encompassing the shaft 7b of the sensing stylus 7, sits in the bore 11 and is conically tapered at an end 12a adjacent the tip 7a of the sensing stylus 7. The through-bore 11 has a corresponding conical taper. The tapered sleeve 12 is provided with an internal thread 13, that is a fine thread, with which an external thread 14 mates, that is formed on the shaft 7b of the sensing stylus 7. A clamping sleeve or collet 15 is arranged further and coaxial to the tapered sleeve 12. At an end thereof, the collet 15 is provided with an external thread 16 which mates and cooperates with a thread 17 at the inside of the bore 11. The collet 15 is further provided with a transverse bore 18 as well as with axial slits 19 in an end thereof, for engagement by a tool for threading the collet 15 into the bore 11.
The shaft 7b of the sensing stylus 7 is in contact with the collet 15 at a rear end thereof, and is guided at that rear end 15a. The sensing stylus 7 further is connected to a handwheel 20 with which the sensing stylus 7 may be rotated and threaded into the collet 15 more or less. A scale 21 on the fixture 3 cooperates with the handwheel 20.
In the known design of mounting the sensing stylus 7 shown in FIG. 3, oscillations thereof, caused by unevenness of the cylinder surface 10a and deviations from a geometrically exact cylinder surface, are transmitted through the tapered sleeve 12 as well as through the collet 15 to the fixture 3. The latter thereby can be excited to natural or self-oscillations, which are transmitted to the engraving stylus 8 and which superimpose themselves on the controlled oscillatory movements of the engraving stylus. Thus the engraving process and thereby the depth and/or surface area of raster cells or wells engraved into the printing cylinder 10 are adversely affected.
FIGS. 4 to 6 illustrate solutions pursuant to the subject invention which avoids a transmission of oscillations from the sensing stylus 7 to the fixtures 3 and the engraving stylus 8. The embodiments of the invention shown in Figs. 4 to 6 distinguish themselves from the known design according to FIGS. 2 and 3 by a different structure and formation of the taper sleeve and the collet. Like reference numerals are used in FIGS. 2 to 6 for like parts.
In the embodiment of the invention shown in FIGS. 4 to 6, the sensing stylus 7 is also mounted in a sleeve 22 which is inserted in the through-bore 11 in the fixture 3. The sleeve 22, having an axial opening or passage 22a, comprises two parts 23 and 24 which are interconnected with each other. The outer sleeve part 23 is also conically tapered at its end 23a adjacent the tip 7a of the sensing stylus 7. The inner sleeve part 24 is provided with an internal thread 25, which is also a fine thread, into which the shaft 7b of the sensing stylus 7 is threaded with its outer thread 14. Between the two sleeve parts or sections 23 and 24, a sleeve-like damping element 26 is arranged and, on the one hand, interconnects the two sleeve parts 23 and 24 with each other, while in effect separating them from each other, on the other hand as well. This damping element 26 comprises an elastically deformable, energy absorbent material, which preferably is an elastomer. Butyl rubber has proved itself as a particularly suitable material. However, it is possible to use natural or nitrile rubber or other rubber or rubber-like materials. The term "elastomer" is hereinafter employed generically to cover natural rubber and synthetic elastomers.
In principle, any material is suitable which, on the one hand, eliminates or at least for the most part prevents a transmission of oscillations from the sensing stylus 7 or from the sleeve part 24 connected thereto to the outer sleeve part 23 and thereby the fixture 3, while, on the other hand, establishing a sufficiently stiff interconnection between the sleeve parts 23 and 24 for a firm and accurate guidance of the sensing stylus 7 in the taper sleeve 22.
A collet 27 is arranged in the through-bore 11 of the fixture 3 coaxially to the taper sleeve 22 and has an external thread 28 at an end thereof. The latter mates with the thread 17 provided at the inside of the bore 11. The diameter of the bore 27a in the collet 27 is somewhat larger than the external diameter of the shaft 7b of the sensing stylus 7. In this manner, a gap or interspace 29 of annular cross-section is provided between the shaft 7b of the sensing stylus 7 and the wall of the through-bore 27a. At its inside, the collet 27 is provided with a circular slot 30 which is open toward the bore 27a.
In that inwardly open slot, a damping element abutting the shaft 7b of the sensing stylus 7 is provided, and is shown at 31 in FIG. 4, at 32 in FIG. 5 and at 33 in FIG. 6. This damping element 31, 32 or 33 serves to guide the sensing stylus 7 on the one hand, and to suppress or prevent a transmission of oscillations of the sensing stylus 7 to the collet 27 and thereby to the fixture 3 on the other hand.
In the embodiment according to FIG. 4, the damping element 31 is an O-ring made of rubber. In the modification shown in FIG. 5, the damping element 32 is formed as a ring of synthetic material, such as "Teflon." FIG. 6 shows an embodiment in which the damping element 33 consists of a ring 34 formed of an elastically deformable, energy absorbent material, which preferably is an elastomer. A guide ring 35 of steel is on the inside of the damping or elastomer ring 34 and is connected thereto.
The mounting arrangements according to the invention shown in FIGS. 4 to 6 effect with the damping element 26 and 31, 32 or 33 a decoupling of the sensing stylus from the fixture 3 and thereby from the engraving stylus 8. As already mentioned, oscillations of the sensing stylus 7 are prevented by damping elements 26, 31, 32, or 33 from being transmitted to the outer sleeve part 23 or to the collet 27. The oscillation energy thereby is entirely or substantially absorbed by the damping elements 26 and 31, 32 or 33, respectively.
It is to be understood that different modifications of the emboidments described above are possible. By way of example, the damping elements 26, 31 and 32 need not be formed of one part as shown in FIGS. 4 and 5. Rather, in similarity to the showing of FIG. 6, multisectional embodiments are possible, whereby at least one of the sections consists of an elastically deformable, energy absorbing material.
It may be possible for certain applications to omit the damping elements 31, 32, 33 between the shaft 7b of the sensing stylus 7 and the collet 27.
Within the scope of the subject invention, a decoupling of the engraving stylus 8 from the sensing stylus 7 with respect to oscillations may be effected in a manner other than as specifically described, as long as there is provided between the sensing stylus 7 and the engraving stylus 8 a suitable damping means that operates as a barrier against oscillations emanating from the sensing organ 7 and as long as there still is the desired firm and accurate guidance of the controlled engraving tool or stylus 8 by the sensing organ or stylus 3 in a common mounting fixture 3. | In an engraving head for apparatus for engraving printing cylinders, a drivable engraving tool and a sensing organ contacting any printing cylinder being engraved by the drivable engraving tool are mounted on a common fixture. A damping element is located between the sensing organ and the engraving tool for at least substantially barring transmission of oscillations from the sensing organ to the engraving stylus, while preserving a firm and accurate guidance of the drivable engraving tool by the sensing organ contacting the printing cylinder. Damped sleeve structures and collets for mounting a sensing stylus include such damping elements. |
BACKGROUND THE INVENTION
The present application is directed to a method for laminating a plastic web onto the surface of an extruded plastic substrate. The plastic web may be a facade strip having a textured appearance and the extruded plastic substrate may be cut into segments after lamination for use in making prefabricated window systems.
An example of a prior art window system having extruded members will now be described with reference to FIG. 1. The window system includes a rectangular mainframe having a top frame portion 10, a bottom frame portion 12, and side frame portions 14 which connect portions 10 and 12. Frame portions 10-14 are made from extruded polyvinyl chloride (PVC) and all have the same cross-sectional configuration, except for features such as drainage channels which are fabricated after extrusion. Because they have the same cross-sectional configuration, frame portions 10-14 can be cut from a long substrate (not shown in FIG. 1) of extruded PVC. Frame portions 10-14 are joined at their corners by edge welds 16 and lateral welds 18 (which are also present on the side of the window system not shown in FIG. 1). The term "weld" in this context means that the corners have been joined by molten PVC which, when it cools, seals one frame portion to an adjacent frame portion along a smooth seam.
The side frame portions 14 provide channels for guiding a screen member 18 and for guiding window units 20 and 22 (which have sashes made from segments cut from an elongated substrate of extruded PVC, not illustrated). Window units 20 and 22 can be unlatched from the channels and tilted out for cleaning as shown. Since the top and bottom frame portions 10 and 12 have the same cross-sectional configuration as the side frame portions 14, channels are also present in top and bottom frame portions 10 and 12. An extruded PVC sill 24 is provided with resilient legs which permit sill 24 to be snap-connected to bottom frame portion 12. Balance mechanisms 25 (only one of which is shown) are mounted in the window guidance channels of side frame portions 14 to counterbalance the weight of window units 20 and 22. Window stops 26 (only two of which are shown) are snap-connected to side frame portions 14 to limit the movement of window units 20 and 22 so as to prevent possible damage to hardware mounted on the window units should they be slammed up or down.
FIG. 2 is a cross-sectional view of the bottom portion of the window system shown in FIG. 1, in its installed state. A rectangular opening in a wall 28 is framed by wooden strips 30 and interior trim 32. Nailing fins 34 are lodged into slots in frame portions 10-14 and are nailed into wall 28 to mount the window system in wall 28.
Further information about the construction of the window system can be found in U.S. application Ser. No. 06/929,303, filed Nov. 12th, 1986, the disclosure of which is incorporated herein by reference.
Since the process of extruding a plastic substrate leaves its own characteristically bland appearance to the surfaces of the substrate, in the past facade strips have been laminated to major visible surfaces of prefabricated plastic window systems to provide a wood-grain appearance. Such strips additionally increase the resistance of the window systems to weathering. However prior art techniques for laminating facade strips to extruded plastic substrates have not been entirely satisfactory. Facade strips laminated with prior art methods have had a tendency to become loose at the ends when segments are cut from a substrate and welded together. Furthermore, due to rough handling that may be encountered during transportation, storage, and installation of prefabricated window systems, the lateral edges of facade strips applied by prior art techniques may peel in places. Long years of exposure to the elements after installation, and possibly the prying hands of small children, may lead to further peeling.
In one prior art method for laminating a facade strip to an extruded plastic substrate, the substrate is moved through a cleaning station, where it is cleaned with soap suds. After drying, an adhesive-backed facade strip is pressed onto the member with rollers.
SUMMARY OF THE INVENTION
An object of the invention is to provide an improved process for laminating a web such as a facade strip to a plastic substrate, and the laminated substrate resulting from the process. A related object is to provide a process for laminating a web tightly to a substrate so that the web does not become detached.
These and other objects which will become apparent in the ensuing detailed description can be obtained by providing a process wherein a surface of the web is coated with a first mixture of solvent and resin and a surface of the substrate is coated with a second mixture of solvent and resin. The solvent and resin have different ratios in the first and second mixtures. The web is then laminated to the substrate by pressing the coated surfaces together and applying heat.
The substrate is preferably made of hard polyvinyl chloride, and the web preferably includes a polymer layer such as hard polyvinyl chloride and a weather proof covering layer such as acrylic. The same type of solvent is preferably used in both mixtures, and preferably the same type of resin is used in both mixtures. The solvent may be dichloromethane and the resin may be a polyester resin.
The mixture coated onto the web preferably has a thickness ranging from about 0.03 mm to about 0.09 mm when it is applied, with subsequent evaporation of solvent reducing the layer thickness to about 0.02 mm before the web and substrate are joined. Within the thickness range of about 0.03 mm to about 0.09 mm when the mixture is applied, a thickness of about 0.06 mm is preferred.
In accordance with another aspect of the invention, in a process for laminating an elongated plastic web to an elongated substrate of extruded thermoplastic the web is moved along a first path and the substrate is moved along a second path, the second path being substantially straight. Each path has an initial portion and a final portion, with the final portions of the first and second paths coinciding. A first mixture is prepared by mixing solvent and resin particles, and the first mixture is coated onto a surface of the web as it moves along the initial portion of the first path. A second mixture is prepared by mixing solvent and resin particles, and the second mixture is applied to the substrate as it moves along the initial portion of the second path. The first mixture has a first ratio of solvent to resin and the second mixture has a different, second ratio of solvent to resin. The coated surfaces are pressed together with at least one pressure roller as the web and substrate move along the common, final portions of the first and second paths.
In accordance with a further aspect of the invention, in a process for making a window system a facade strip is moved along a first path and an elongated substrate of extruded plastic is moved along a second path, which is substantially straight. Both paths have initial and final portions, with the final portions coinciding. A first mixture of solvent and resin particles is prepared and coated onto a surface of the facade strip as it moves along the initial portion of the first path. Similarly, a second mixture of solvent and resin particles is prepared and coated onto a surface of the substrate as it moves along the initial portion of the second path. The ratio of solvent to resin in the mixtures is different. The facade strip is attached to the substrate by pressing the coated surface of the strip against the coated surface of the substrate with at least one pressure roller as the strip and substrate move along the final portions on their paths. Thereafter the substrate is cut into a plurality of sections. A rectangle is formed by joining four sections together.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a prior art window system having extruded plastic members;
FIG. 2 is a vertical sectional view through the bottom portion of the window system of FIG. 1 after installation in a building;
FIG. 3 is a side view schematically illustrating an apparatus for laminating a facade strip to a plastic substrate in accordance with the method of the present invention, the substrate and laminated facade strip thereafter being cut into segments for fabrication of the mainframe of the window system shown in FIGS. 1 and 2;
FIG. 4 is a cross-sectional view taken through line 4--4 of FIG. 3;
FIG. 5 is a sectional view through the facade strip and a portion of the substrate after lamination;
FIG. 6 is a sectional view corresponding to FIG. 4, but illustrating the substrate supported in a different orientation so that a differently-configured pressure roller can laminate a facade strip on different surfaces; and
FIG. 7 is a sectional view illustrating a modified embodiment wherein different pressure rollers are used to laminate a web to different portions of the surface of a substrate.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The process of the present invention may be employed to laminate webs such as facade strips to various extruded PVC substrates before the window system of FIG. 1 is fabricated, thereby improving the appearance and weather-resistance of major visible surfaces of the window system. For example, facade strips may be used to impart a textured or wood-grain appearance to surfaces 36, 38, and 40 (see FIG. 2) of frame portions 10-14 in FIG. 1, as will be described in detail below. Although not all major visible surfaces of the window system need facade strips in order to provide a substantial aesthetic improvement, facade strips are preferably also laminated to the major visible surfaces of sill 24, the sashes of window units 20 and 22, and stops 26.
In FIG. 4, an elongated, extruded PVC substrate 42 is retained in a support 44 while a web such as facade strip 46 is laminated on surface 36 (see FIG. 2). Support 44 includes a first elongated prop 48 which conforms generally to one side of substrate 42 and a second elongated prop 50 which conforms generally to the other side. Prop 50 includes tongues 52 which extend into what will become the window channels of side frame portions 14 (see FIG. 1), and a tongue 54 which extends into what will become the screen channel. Tongues 52 and 54 support various walls and flanges of substrate 42 so as to reduce deformation of substrate 42, when pressure is applied at surface 36, to a negligible amount. Support 44 also includes an elongated trough 56 which holds props 48 and 50, with substrate 42 sandwiched between them. A portion 58 of substrate 42 rises above props 48 and 50.
FIG. 3 schematically illustrates an installation for laminating the strip 46 onto substrate 42. A conveyor belt 60 is transported by rollers 62 to advance support 44 in the direction of arrow 64. The substrate 42 moves beneath a cleaning station 64, which includes a solvent dispenser 66, a resinous particle dispenser 68, a mixer which 70 mixes the solvent and particles, and a cleaning chamber 72 in which the mixture is wiped onto surface 36 of substrate 42. The solvent is preferably methylene choride and the resin is preferably a polyester resin. The mixture of resin and solvent is about 5% by weight resin and about 95% by weight solvent.
After exiting the cleaning station 64, the coated surface 36 moves into an elongated drying chamber 74. The solvent is removed here by evaporation, leaving a sticky surface. Chamber 74 is preferably maintained at a temperature between 50° C. and 60° C.
As is shown in FIG. 5, facade strip 46 has a base layer 75 of hard PVC and an acrylic layer 76 which is bonded to layer 75. Layer 76, which is textured to provide a woodgrain appearance, is extremely water-resistant. Layers 75 and 76 are each 0.1 mm thick. Returning to FIG. 3, the facade strip 46 is unwound from a supply reel 78 and travels past an adhesive-coating station 80. Adhesive coating station 80 includes a resinous particle dispenser 82, a solvent dispenser 84, a mixer 86, and a coating chamber 88. The resin is again preferably a polyester resin and the solvent is again preferably methylene chloride. The mixture preferably includes about 30% by weight resin and about 70% by weight solvent. The mixture is coated onto strip 46 so as to form a layer ranging from about 0.03 mm to about 0.09 mm thick (preferably about 0.06 mm). After leaving the adhesive coating station 80 the strip 46 advances into drying chamber 90, which is preferably maintained at a temperature of 50° C. to 60° C. in order to evaporate the solvent. An adhesive layer remains after drying, the adhesive layer preferably being about 0.02 mm thick. After it exits drying chamber 90, the adhesive-coated strip 46 passes over deflection roller 92 and begins moving downward. It will be apparent that the side of strip 46 that is coated with adhesive faces away from roller 92.
The direction of strip 46 changes again at pressure roller 94, where the initial stage of the actual lamination of strip 46 to surface 36 occurs. Pressure roller 94 is followed by pressure rollers 96, 98, and 100. Pressure rollers 94-100 are rotatably mounted on shafts 102 which are spaced about a meter apart. Rollers 94-100 press the coated strip 46 against the coated surface 36 of substrate 42. Although not illustrated, the vertical positions of shafts 102 may be adjusted to different heights to accommodate the dimensions of various substrates (not illustrated) on which facade strips are to be laminated. Heated blowers 104 (only one of which is shown) are positioned between pressure rollers 94-100 to direct hot air toward the strip 46 and substrate 42 as the pressure is being applied by rollers 94-100. The hot air extends the entire width of strip 46 and preferably has a temperature in the range of 60° C. to 100° C.
It has been found that a strip 46 laminated by means of the process of the present invention sticks with remarkable tenacity to the underlying surface 36. After lamination and curing for seven days, it has been found that strip 46 can only be torn off in patches if a deliberate attempt is made to remove it. That is, the strip itself is destroyed, and not the adhesive interface.
With reference to FIG. 5, the reason for the remarkable adhesion attained by the method of the present invention is believed to be as follows: The resinous particles from dispensers 68 and 82 do not entirely dissolve in the solvent, and leave undissolved particles in the micron range after the solvent has been evaporated in drying chambers 74 and 90. Furthermore a small portion of the solvent migrates into the surfaces of substrate 42 and layer 75 of strip 46, and is not evaporated during passage through drying chambers 74 and 90 but instead temporarily softens the surface regions of substrate 42 and layer 75. FIG. 5 illustrates an adhesive layer 106 which results when the mixture applied to substrate 42 has been dried in chamber 74, and an adhesive layer 108 which results when the mixture applied to strip 46 has been dried in chamber 90. Layers 106 and 108 represent the residue remaining from completely dissolved resin after the solvent has been evaporated. FIG. 5 also illustrates a resin particle 110 which was not completely dissolved when the mixture was coated onto strip 46. Due to surface tension in the mixture around particle 110 immediately after coating, adhesive layer 108 has portions 112 of increased thickness immediately adjacent particle 110. When strip 46 is pressed against surface 36 by pressure rollers 94-100, adhesive layers 106 and 108 stick tightly (and after a curing period the layers 106 and 108 merge into each other so as to become a single layer). Furthermore particle 110 is slightly flattened by the pressure, and protrudes into the softened surface regions of substrate 42 and strip 46. The particle 110, which is securely held to strip 46 by portions 112, thus bites into both the strip 46 and substrate 42 to increase the mechanical strength of the bond between the two. Furthermore the presence of particle 110, and a myriad of others (not illustrated) like it, roughens the surfaces to be joined and increases the bonding area, as is apparent from the thinning of layers 106 and 108 in FIG. 5 as they pass beneath particle 110. In short, it is believed that particles of resin remain un-dissolved and augment the adhesive effect in the manner described in this paragraph and illustrated schematically in FIG. 5; regardless of whether or not this theory explaining the superior adhesion is accurate or not, however, the fact remains that t he lamination procedure illustrated in FIG. 3 achieves firm bonding between the strip 46 and the substrate 42.
FIG. 6 illustrates a support 114 for holding the substrate 42 while modified pressure rollers 116 (only one of which is shown) press a facade strip 118 against surfaces 38 and 40 (see FIG. 2) of substrate 42. Support 114 includes a prop 120 and a prop 122 with support tongues which extend into the channels of member 42. Support 114 additionally includes the trough 56, which encloses props 120 and 122.
After strips 46 and 118 have been laminated onto substrate 42, the substrate 42 is cut into segments for use as frame portions 10-14 of the window system shown in FIGS. 1 and 2.
In the embodiment schematically illustrated in FIG. 7, an elongated substrate 124 of extruded thermoplastic is held by a support 126 which includes a trough 128 and an elongated backing element 130. Substrate 124 includes a curved portion 132, a first flat portion 134, and a second flat portion 136 to which an elongated web (not shown) is to be laminated. As is illustrated, the upper surface of backing element 130 conforms to portions 132, 134, and 136. Pressure roller 138 is rotatably mounted on shaft 140, which urges pressure roller 138 in the direction of the arrow shown with a solid line so as to press the web against the surface of portion 132. It should be noted that the surface of roller 138 conforms to the curve of portion 132. A pressure roller 142, shown in dotted lines to indicate that it is located behind roller 138 and beneath the plane of the drawing, presses the web against surface 134. This is indicated by the arrow shown with a dotted line. Behind roller 142 and thus further beneath the plane of the drawing is a pressure roller 144 which presses the web against portion 136.
It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. | In a method for laminating a plastic web onto a plastic substrate, the web is moved past an adhesive coating station where one surface is coated with a mixture made of solvent and resin particles. The substrate is moved past a cleaning station, where a surface is also coated with a mixture made of solvent and resin. After the web and substrate pass through drying chambers, the coated surfaces are pressed together with rollers and heat is applied. The method is particularly suitable for laminating strips bearing a woodgrain pattern onto extruded thermoplastic members which are thereafter cut into segments for use in making prefabricated window systems. |
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 12/369,458, filed Feb. 11, 2009 (now allowed), which claims the benefit of commonly-assigned U.S. Provisional Patent Application No. 61/113,141, filed Nov. 10, 2008, both of which are hereby incorporated by reference herein in their entirety.
BACKGROUND OF THE INVENTION
This invention relates to controlling the backlighting of a video display. In particular, this invention relates to control of backlighting separately from the video display itself without introducing visual artifacts in the display.
In early video displays based on cathode-ray tube technology, the display generated its own light. However, in many types of solid-state video displays, the elements that display the video data do not generate their own light, and must be coupled with a separate light source. For example, liquid crystal displays operate by selectively lightening and darkening elements in an array, allowing light to shine through from behind the array. In such displays, the light source is generally a backlight, although for some displays, light may be provided from the sides, using reflectors, light pipes, etc., to spread the light out behind the liquid crystal array.
One type of light source commonly used in such displays includes fluorescent lamps. More recently, however, in order to reduce power consumption, and to save space, thereby allowing thinner displays, solid-state light sources have been introduced. For example, light-emitting diodes can be used, either in an array behind the liquid-crystal image-forming array, or as sidelights, with the light distributed behind the image-forming array using reflectors, light pipes, etc., as described above.
It is sometimes necessary to vary the brightness of a video display. This may be a function of the image being displayed, or it may be done to conserve power (e.g., in a portable device, the brightness may be reduced when operating on battery power, particularly during idle periods). One way of controlling the brightness is by pulse width modulation, in which a current pulse of duration t 2 is sent during each interval of duration t 1 to power the light source. Maximum brightness may be achieved when t 2 is a certain fraction f of t 1 , where f≦1. By narrowing each pulse—i.e., shortening the pulse width, so that t 2 <ft 1 , the brightness can be reduced. The magnitude of each current pulse may remain constant.
The video array itself may have a certain refresh rate, which may be determined, for example, by the video standard being displayed, such as, e.g., NTSC, ATSC, VGA, SVGA, XVGA, etc. The video refresh rate may be totally independent of the pulse-width modulation pulse rate 1/t 1 . This complete lack of a fixed-phase relationship between the two signals may result in motion artifacts (e.g., a “waterfall” effect) in the video display when the refresh pulses do not coincide with the pulse-width modulated current pulses, for which there may be a number of solutions.
One solution is to synchronize the video refresh rate and the pulse-width modulation pulse rate of the backlight control current, so that the pulse-width modulation pulse rate of the backlight control current is an integer multiple of the refresh rate. This solution requires deriving both signals from a common clock source (e.g., a quartz crystal).
Another solution is to greatly increase the pulse-width modulation pulse rate of the backlight control current, so that when a video refresh pulse occurs, it will be very close to a backlight control current pulse so as to be nearly synchronous to the current pulse.
For example, a common video refresh rate is 60 Hz, while a common pulse-width modulation pulse rate for the backlight control current is 600 Hz. Either the 600 Hz backlight control current pulses may be synchronized with the 60 Hz refresh pulses, or the pulse-width modulation pulse rate of the backlight control current may be increased to between about 20 kHz and about 30 kHz. However, the video subsystem and the backlight subsystem are typically completely separate, so that synchronizing both rates using a common clock source is not practical or desirable, and very high pulse-width modulated backlight control current pulse rates also are not desirable.
Another solution might be to restart the pulse-width modulated backlight control current pulse train on each occurrence of a refresh pulse. However, because the pulse rate and the refresh rate may be completely independent, it may occur, by happenstance, depending on how the two cycles overlap, that a current pulse will have occurred just before a refresh pulse. Then, if the pulse train is restarted on occurrence of the refresh pulse, another current pulse will occur. The occurrence of two current pulses close together may cause a noticeable, if momentary, brightness increase or “flicker,” which also is undesirable.
SUMMARY OF THE INVENTION
In accordance with the present invention, in a pulse-width modulated backlight control for a video display, the pulse-width modulated backlight control current pulse train is resynched to the video refresh rate on occurrence of a video refresh pulse. In order to prevent an undesirable momentary increase in brightness, or flicker, in the event that the pulse train is restarted soon after a pulse has occurred relative to the normal pulse interval, this resynchronization does not result in immediate restart of the pulse-width modulated backlight control current pulse train at full pulse width. Instead, the width, and possibly the timing, of the first backlight control current pulse after resynchronization are adjusted so that the duty cycle remains constant, to avoid any perceptible flicker.
In one embodiment, the first backlight control current pulse after resynchronization occurs essentially on occurrence of the video refresh pulse, so that it is closer to the previous backlight control current pulse than a normal pulse-width modulation pulse interval. In this embodiment, to mitigate the flicker effect of having the first backlight control current pulse after resynchronization closer than normal to the previous pulse, the width of the first backlight control current pulse after resynchronization is reduced from a first value determined by the desired brightness to a second value that bears the same proportion to the first value that the interval between the beginning of the previous backlight control current pulse and the beginning of the first backlight control current pulse bears to the normal pulse interval. Thus, the average duty cycle, over the combination of the shortened pulse interval before the video refresh pulse and the first pulse interval after the video refresh pulse, is constant, minimizing or eliminating perceptible flicker.
In a second embodiment, the first backlight control current pulse after resynchronization still occurs one pulse-width modulation pulse interval after the rising edge of the previous backlight control current pulse, while the second backlight control current pulse after resynchronization occurs one pulse-width modulation pulse interval after the rising edge of the video refresh pulse. To mitigate the flicker effect from having those first and second pulses closer together than one pulse-width modulation pulse interval, the width of the first backlight control current pulse may be reduced from a first value determined by the desired brightness to a second value that bears the same proportion to the first value that the interval between the beginning of the first backlight control current pulse and the beginning of the second backlight control current pulse bears to the normal pulse interval. In that way, the duty cycle during the shortened pulse interval is the same as that during a normal pulse interval, and there is no perceptible increase in backlight brightness.
By definition, the first backlight control current pulse after resynchronization occurs during a new video frame. In some cases, characteristics of the next video frame may require a brightness change. Therefore, the unadjusted pulse width after resynchronization may be different from the unadjusted pulse width before resynchronization. In either of the two embodiments described above, the pulse width update for any brightness change that may be required can occur either in the first backlight control current pulse after resynchronization or the second backlight control current pulse after resynchronization. In the former case, the adjustment of the pulse width may be applied to the updated pulse width.
Thus, in accordance with the present invention there is provided a method for controlling a backlight associated with a video display, the video display having a refresh rate. The method includes generating a train of pulse-width modulated current pulses, each of the pulse-width modulated current pulses having a pulse width determined by a leading edge and a trailing edge (i.e., a rising edge and falling edge for a positive-going pulse, or a falling edge and a rising edge for a negative-going pulse) and determined by desired backlighting parameters of a present frame, and leading edges of successive ones of the pulses being separated by a uniform pulse interval. On occurrence of a refresh of the video display after an incomplete pulse interval following one of the pulse-width modulated current pulses to start a next frame, the pulse train is restarted and the pulse width of a subsequent pulse is shortened so that the pulse width of the subsequent pulse is reduced from a first value determined by the desired backlighting parameters to a second value that bears a same proportion to the first value that the duration between the beginning of the incomplete pulse interval and a leading edge of the refresh pulse bears to the uniform pulse interval. A pulse following the subsequent pulse occurs one uniform pulse interval following the leading edge of the refresh pulse.
A video display operated in accordance with the method also is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features of the invention, its nature and various advantages will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:
FIG. 1 is a simplified schematic representation of a video display with which the present invention may be used;
FIG. 2 is a graphical representation showing a backlighting control pulse train that is synchronized with a video refresh signal;
FIG. 3 is a graphical representation showing a backlighting control pulse train that is not synchronized with a video refresh signal;
FIG. 4 is a graphical representation of a first embodiment of a method according to the present invention;
FIG. 5 is a graphical representation of a second embodiment of a method according to the present invention; and
FIG. 6 is a diagram of circuitry according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows, schematically, a video display 100 of the type with which the present invention may be used. Video display 100 includes a video array 101 which may be, e.g., a liquid crystal array as described above, and a backlighting source 102 . Although backlighting source 102 is shown as having an area coextensive with that of video array 101 , the actual light source of backlighting source 102 may occupy a small area, and its output may be spread over video array 101 using appropriate reflectors, light pipes, etc. (not shown).
Driver circuitry 103 may include a video driver 104 that drives video array 101 , and a separate backlight control 105 for backlighting source 102 .
FIG. 2 shows a train 201 of pulse-width modulated current pulses 202 for controlling backlighting unit 102 . The pulse interval t 1 is the duration between the rising edges 212 of adjacent pulses 202 . The brightness of backlighting source 102 may be determined by the duty cycle of pulse train 201 —i.e., the proportion that the width or duration t 2 of each pulse 202 bears to the pulse interval t 1 , which may be expressed as a percentage, or as a fraction f. Although the accompanying drawings show positive-going pulses and the discussion that follows refers to the rising and falling edges of those pulses, the invention also applies where the pulses are negative-going. Accordingly, any discussion of rising and falling edges should be considered a discussion of falling and rising edges in the case of negative-going pulses. More generally, one may refer to the leading and trailing edges of the pulses.
Also shown in FIG. 2 is a voltage waveform v sync , made up of a train 203 of refresh pulses 204 occurring at a refresh interval t 3 which generally is much longer than pulse interval t 1 . Generally, one may expect refresh interval t 3 to be at least about ten times as long as pulse interval t 1 .
In the example of FIG. 2 , pulse-width modulated pulse train 201 is synchronized with v sync or refresh pulse train 203 , with each refresh pulse 204 coinciding with a pulse-width modulated current pulse 202 . In this case, no visual artifacts are produced.
In the situation shown in FIG. 3 , on the other hand, the refresh pulses do not always coincide with one of the pulse-width modulated current pulses of pulse train 301 . In particular, while refresh pulse 302 coincides with current pulse 303 , refresh pulse 304 occurs shortly after current pulse 305 and refresh pulse 307 occurs shortly after current pulse 308 . The resulting restart of the pulse-width modulated current pulse train causes current pulse 306 to occur much closer than normal to current pulse 305 and current pulse 309 to occur much closer than normal to current pulse 308 , giving rise to the increased brightness, and therefore flicker, referred to above. It will be appreciated, of course, that refresh pulse 304 could occur at any time relative to the current pulses of pulse train 301 . Nevertheless, any degree of closeness between pulses 305 and 306 could give rise to at least some visual artifact.
In an alternative situation (not shown), the pulse-width modulated current pulse train is not synchronized with the refresh pulse train, and is not restarted on occurrence of a refresh pulse. That situation would give rise to the aforementioned “waterfall” effect.
In accordance with one embodiment of the invention, as shown in FIG. 4 , first backlight control current pulse 401 after resynchronization occurs at interval t 1 following the previous backlight control current pulse 402 before resynchronization, and the second backlight control current pulse 403 after resynchronization occurs at interval t 1 following refresh pulse 304 . In this embodiment, even though pulse 402 occurs after refresh pulse 304 , it may be considered the last pulse of the pre-refresh pulse train. This results in pulse 401 and pulse 403 being separated by an interval equal to the interval between the rising edge of pulse 402 and the rising edge of refresh pulse 304 , rather than interval t 1 . The amount by which this closer than interval t 1 depends on how soon pulse 304 occurred after pulse 402 .
In any event, according to this embodiment, the width of pulse 401 is shortened so that the proportion that the adjusted width 411 of pulse 401 bears to the unadjusted width 421 of pulse 401 is the same as the proportion that the interval between the rising edge 431 of pulse 401 and the rising edge 433 of pulse 403 bears to the uniform or standard pulse interval t 1 , which is the same as the proportion that the interval between the rising edge 432 of pulse 402 and the rising edge 334 of pulse 304 bears to the standard pulse interval t 1 . Accordingly, the duty cycle over the shortened interval t 4 between pulse 401 and pulse 403 is the same as during a standard pulse interval t 1 .
According to a second embodiment shown in FIG. 5 , first backlight control current pulse 501 after resynchronization occurs substantially at the same time as refresh pulse 304 , and all subsequent pulses are spaced apart by the standard pulse interval t 1 . In this embodiment, pulse 502 may be considered the first pulse of the post-refresh pulse train. This results in pulse 501 and previous pulse 502 being separated by an interval equal to the interval between the rising edge of pulse 502 and the rising edge of refresh pulse 304 , rather than interval t 1 . The amount by which this closer than interval t 1 depends on how soon pulse 304 occurred after pulse 402 .
In any event, according to this embodiment, the width of pulse 501 is shortened so that the proportion that the adjusted width 511 of pulse 501 bears to the unadjusted width 521 of pulse 501 is the same as the proportion that the interval between the rising edge 532 of pulse 502 and the rising edge 531 of pulse 501 bears to the standard pulse interval t 1 , which is the same as the proportion that the interval between the rising edge 532 of pulse 502 and the rising edge 334 of pulse 304 bears to the standard pulse interval t 1 . Accordingly, the average duty cycle over the shortened interval t 5 between pulse 502 and pulse 501 and the following pulse interval is the same as during a standard pulse interval t 1 .
If in the embodiment of FIG. 5 , refresh pulse 304 occurs before pulse 502 is complete, pulse 502 is allowed to complete, and then is immediately followed by pulse 501 . This again maintains the average duty cycle over the two intervals containing pulse 502 and pulse 501 the same as during a standard pulse interval t 1 .
In either embodiment, the second pulse 403 , 503 following refresh pulse 304 occurs one standard pulse interval t 1 following refresh pulse 304 .
It may be that the requirements of the video frame to be displayed following refresh pulse 304 require a brightness change. This can be handled in two ways, regardless of whether the embodiment of FIG. 4 or the embodiment of FIG. 5 is being used. According to one variant, the brightness change is introduced immediately on occurrence of refresh pulse 304 . According to this variant, the adjustment of pulse width 411 or 511 must also account for the brightness change. Although this is possible, it may be mathematically complex. Therefore, according to a second variant, the brightness change is not applied until pulse 403 , 503 . This one-pulse delay in applying the brightness change should not cause any perceptible visual artifact.
FIG. 6 shows an embodiment of a counter arrangement 600 for implementing the invention. c 1 counter 601 controls the standard pulse interval t 1 between the pulse-width modulated backlight control current pulses in pulse train 301 , while c 2 counter 602 controls the pulse width of the individual pulse-width modulated backlight control current pulses.
c 0 counter 610 supplies CLK 1 clock 620 which clocks counters 601 , 602 . As such, CLK 1 is significantly faster (e.g., between about 100 times and several tens of thousands of times faster) than the pulse rate of pulse train 301 . For example, the pulse rate of pulse train 301 may be between about 300 Hz and about 30 kHz, while CLK 1 may be between about 4096 times faster and about 16,384 times faster. Counter 610 is itself clocked by an even higher-speed system clock CLK 0 (e.g., a 200 MHz clock) to generate CLK 1 . Counter 610 may be loaded with a maximum count value r 0 that determines CLK 1 =CLK 0 /r 0 . Alternatively, an independent clock circuit (not shown) may generate CLK 1 directly.
Similarly, counter 601 may be loaded with a maximum count value r 1 that determines t 1 =1/(CLK 1 /r 1 ), while counter 602 may be loaded with a maximum count value r 2 that determines t 2 =1/(CLK 1 /r 2 )=t 1 (r 2 /r 1 ). r2 may be changed by driver circuitry 103 according to the brightness requirements of the present image.
These relationships hold as long as no v sync refresh pulse 304 occurs. However, once a refresh pulse 304 occurs, the instantaneous count value c 1 in counter 601 is stored at 611 as m 1 , and used at 603 to derive a new temporary maximum count m 2 for counter 602 , such that m 2 bears the same proportion to r 2 that m 1 bears to r 1 , or m 2 =r 2 (m 1 /r 1 ).
If operating according to the method shown in FIG. 4 , counter 601 is not reset by pulse 304 . Instead, it continues to run until c 1 =r 1 , at which point it triggers counter 602 . Because there is a value in m 2 , m 2 is used instead of r 2 (otherwise r 2 would be used) causing a pulse to be output for a duration indicated by m 2 . m 2 is cleared whenever it is used, and therefore the next pulse will again have the duration indicated by r 2 . Counter 601 then starts again. Because there is a value in m 1 , m 1 is used instead of r 1 , and counter 602 is triggered after a shortened interval t 4 indicated by m 1 . m 1 is then cleared, having been used, so that the next pulse interval will be determined by r 1 .
If operating according to the method shown in FIG. 5 , counter 601 , including m 1 , is reset by pulse 304 after m 2 has been stored. This triggers counter 602 . Because there is a value in m 2 , m 2 is used instead of r 2 causing a pulse to be output for a duration indicated by m 2 . m 2 is cleared whenever it is used, and therefore the next pulse will again have the duration indicated by r 2 . Because m 1 has been reset, that next pulse will occur after the standard interval determined by r 1 .
It will be 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. One skilled in the art will appreciate that the present invention is not limited by the disclosed embodiments, which are presented for purposes of illustration and not of limitation, and the present invention is limited only by the claims that follow. | A pulse-width modulated backlight control for a video display restarts the pulse-width modulated pulse train on occurrence of a video refresh pulse. In order to prevent an undesirable momentary increase in brightness in the event that the last pulse of the pre-refresh pulse train occurs too close to the first pulse of the post-refresh pulse train relative to the normal pulse interval, the width of the first pulse following refresh may be reduced from a first value determined by the desired brightness to a second value that bears the same proportion to the first value that the interval between the beginning of the previous pulse and the occurrence of the refresh pulse bore to the normal pulse interval. In that way, the duty cycle during the shortened pulse interval is the same as during a normal pulse interval, avoiding or minimizing perceptible increase in backlight brightness. |
TECHNICAL FIELD
The present invention is in the field orally administered liquid compositions for delivering pharmaceutical actives to humans and animals.
BACKGROUND
Pharmaceutical actives are generally delivered using dosage forms designed to promote ease in using while encouraging maximum efficacy of the active. Among the challenges regarding creating dosage forms taken by mouth is formulating such a product in a form small enough to be easily swallowed.
When the desired dosage form is a liquid, then the pharmaceutical actives or actives must be solubilized in a vehicle wherein the composition is easy to use and maximizes therapeutic effectiveness. One such composition is a pharmaceutical suspension. A suspension is where solid active particles are dispersed within a liquid vehicle. Although suspensions are a very useful way to concentrate an active in a small volume, they possess some inherent disadvantages. One disadvantage is that over time the active particles settle to the bottom or float to the top of the liquid, resulting in a suspension that is not homogenous. Thus, a patient who uses a suspension in such a condition is likely to receive more or less active than the intended dose. In some cases this could result in a consumer taking a high and potentially a hazardous dose or conversely, a dose that lacks the minimum level of active required to provide the intended therapeutic benefit. Another disadvantage of suspensions relates to absorption of the active. For absorption to take place, a pharmaceutical active must first be in a solubilized state. Thus, suspensions that contain actives not previously solubilized must undergo dissolution in bodily fluids prior to absorption. Such a dissolution step may slow down the onset of the desired therapeutic effect.
In light of the disadvantages of suspensions mentioned above, those skilled in the art have created solutions in the form of elixirs and syrups for delivery of actives. These solutions can be easily and conveniently swallowed in 5, 10 or even 50 ml volumes. In certain cases, however, it is desirable to deliver the active in a true solution that is in a small volume of less than about 3 ml, even less than 1 ml. Up to now, achieving such small volumes has been problematic and for some actives nearly impossible. The problem is exacerbated where the dose level of the active is required to be large, or wherein the active agent is especially insoluble in the usual vehicles used for pharmaceuticals.
Liquid-filled, soft gelatin capsules were developed in response to this challenge. There are, however, limits to using such capsules. One limitation is when the requisite level of actives cannot be contained in a small volume. Liquid-centered, soft gelatin capsules containing acetaminophen has been the subject of a great deal of effort in order to solve problems such as those mentioned above. For example, in U.S. Pat. No. 5,505,961, assigned to R. P. Scherer reputes to have solved such problems associated with soft gelatin capsules, particularly where high dose levels of acetaminophen is required to provide therapeutic benefits. It is disclosed therein that acetaminophen, with or without other actives, is soluble in solvents including polyethylene glycol, water, propylene glycol, a solubilizing agent including potassium (or sodium) acetate and polyvinylpyrrolidone or PVP. It is disclosed therein, PVP is essential for inhibiting crystallization in such compositions. PCT Application WO 93/00072, Coapman, discloses a process for solubilizing pharmaceutical actives considered difficult to solubilize. This process requires PVP to aid in solubilizing the active agent and preventing precipitation. Similar limitation are disclosed for the acetaminophen solutions described in PCT Application WO 95/23595, by Dhabhar, wherein PVP is disclosed as an essential component of the compositions that are the subject matter of the patent.
PVP is a high molecular weight polymer that while inhibiting crystallization, also is responsible for increasing compositional viscosity of the liquid compositions. Such a viscosity increase is not significant for products contained in capsules intended for swallowing. The high viscosity associated with such liquid compositions containing PVP, however, does inhibit effective oral dosing of low volume products particularly from exact dosing implements such as medicine droppers, oral syringes, dosing cups and sachets. High viscosity liquid compositions are an impediment to being easily dosed from these types of exact dosing implements and do not spread easily over large surface areas of oral mucosal tissue.
When avoiding PVP and its related problems, new problems associated with oral dosing can develop. For example, U.S. Pat. No. 5,360,615, assigned to R. P. Scherer, discloses solubilizing the active by adding acid or base to cause the partial ionization of the active. It has been found, however, that this approach is undesirable in the case of liquid solutions to be delivered into the mouth for absorption through mucosal membranes since the active's ionization inhibits such absorption.
One very important consideration in choosing a product form, therefore, is determining the active's intended delivery site within the body. The prior art describing medicaments to be delivered to the stomach include liquid-center gelatin capsules. The liquids contained in these capsules are not intended to contact the body until the gelatin shell dissolves in the stomach. In such a product it is superfluous whether the liquid in the gelatin is highly viscous, or even a paste or solid. For administration into the mouth, however, the composition's ability to flow is critical. Low viscosity liquids permit accurate administration from current or developing exacting dispensing or dosing devices for administering a liquid composition to a person. Low viscosity liquids are easier to swallow and make the composition acceptably palatable. Such consumer acceptance is very important for encouraging consumers to comply with dosing instructions to receive the intended therapeutic benefit. Aside from the aesthetic considerations, it's desired that the formulation spread over a large surface area of mucosal tissue to enhance the diffusion of the respective actives within the formulation through the mucosal membranes.
SUMMARY OF THE INVENTION
The inventors here have worked to create compositions comprising pharmaceutical actives normally difficult to solubilize in high concentration for delivery into the mouth. The fundamental relationship between the pharmaceutical actives and the vehicles into which they are incorporated is that the actives are maintained in solution while the in-use character of the composition is flowable as well as a pourable for enhancing the delivery of the pharmaceutical actives to the oral cavity.
After diligent research in trying to obtain such compositions, the inventors have surprisingly discovered that there is an important relationship of the components comprising the vehicle for solubilizing the active. When the components of the vehicle are in the particular levels and ratios to one another as shown in FIG. 1 , the pharmaceutical actives remain in solution and are pourable and flowable at temperatures other than ambient temperature such as body temperature.
The present invention, therefore, is an orally administered liquid pharmaceutical composition that demonstrates excellent physical stability while delivering concentrated levels of the pharmaceutical active(s). Specifically, these compositions do not exhibit active precipitation from the solution for extended periods. Other advantages of this invention include uniform and correct dosing to patients. Additionally, the compositions remain liquid in the oral cavity thereby exposing large surface areas of oral mucosal tissue to the pharmaceutical actives intended to pass through that oral mucosal tissue. As a result, the compositions are efficacious and patient-preferable due to their improved palatability. The formulations also permit the solubilization of both lipophilic active agents, and hydrophilic excipients and formulation aids at the same time.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 illustrates a ternary mixture diagram that is a graphical representation of three varying relationships of the three primary components of the vehicle of compositions of the present invention. The axes of the diagram correspond to these three components.
DEFINITIONS
Terms useful herein are defined below. Additionally, terms used in the art, as well as general concepts, are further described in Schramm, The Language of Colloid and Interface Science , American Chemical Society, (1993), incorporated herein by reference:
“Hydrophilic solvents” are used herein to describe polar, pharmaceutically acceptable solvents that are miscible with water and possess a dielectric constant (ε) of approximately 20 or greater as found in Martin's Physical Pharmacy, Fourth Edition, Pages 213–214.
“Low volume dose” as used herein means doses of a liquid composition less than about 3 mls wherein the pharmaceutical active is sufficiently concentrated to produce the desired therapeutic response upon oral administration.
“Optical density” or “OD” is a measurement of the absorption of radiation by a mixture of ingredients forming a liquid or a layer of said liquid. The OD is expressed mathematically as the negative common logarithm of the transmittance of light (T) by the mixture. Optical density value is measured using the equation, OD=log10 (1/T).
“Orally administered” as used herein means the composition is introduced into the oral cavity making contact with the tissues inside the oral cavity prior to it being swallowed or ingested.
“Physical stability” as used in the context of the present composition means the composition's resistance to changes in the number and relative amounts of phases of matter present.
“Pourable” as used herein means the ability of a liquid to remain in a highly flowable state regardless of the exposure of said liquid to temperatures from about 15° C. to about 40° C. at normal atmospheric pressure.
“Solution” as used herein means a uniform dispersed mixture at molecular or ionic level of one or more pharmaceutical actives (the solute) in one or more other substances (the solvent). The physical state of the solution at normal ambient conditions is such that it is readily dispensed from a vessel by pouring.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is an orally administered liquid pharmaceutical composition having excellent physical stability while containing concentrated levels of pharmaceutical actives. In addition to these pharmaceutical actives, these compositions comprise a vehicle for solubilizing the actives wherein the vehicle comprises hydrophilic solvents, polyoxyalkylene block copolymers and water together in levels and ratios to one another wherein the actives are solubilized and remain as such over extended periods of time. Hydrophilic solvents and water also facilitate the incorporation of other compounds, such as sweetening agents and stabilizers, into the composition of the present invention. Compositions of the present invention provide accurate delivery of the active, particularly when the composition is packaged in exacting dose measuring devices including graduated tubes, droppers, pipettes, single or unit dose liquid elixir packages, atomizers, liquid filled edible capsules or drops or other such packages. In addition, these solutions readily spread over large surface areas of the mucosal tissues in the oral cavity, throat, oropharynx and combinations thereof, resulting in some actives being rapidly absorbed.
Consumers show strong preference for lower dose volumes that contain a sufficiently high enough concentration of pharmaceutical actives to provide the desired therapeutic benefit of the active. As a result of this effort to meet consumer needs, the compositions of the present invention are intended to be dosed in low volumes. In the present invention it is envisioned that the maximum volume of a single dose of the compositions of the present invention is no greater that about 3 ml, alternatively no greater than 2.5 ml.
All percentages of the components comprising the invention are herein referred to by their weight of the composition.
Pharmaceutical Actives
The pharmaceutical actives of the present invention are those that are particularly difficult to solubilize in a small volumes of solvents since the actives are already close to their solubility limit. At such concentrations these pharmaceutical actives tend to be physically unstable, precipitating out of solution when the composition is subject to minor changes in ambient temperature, level of contaminates in the solution or other commonly known factors that precipitate an active from a solution. Precipitation can take place at any point from just after manufacture and packaging of the compositions, through its normally expected shelf life.
The compositions of the present invention contain pharmaceutical actives that are soluble in the polyoxyalkylene block copolymers, hydrophilic solvents and water that comprise the vehicle of the composition of the present invention. The pharmaceutical actives include guaifenesin alone or in combination other actives selected from the group of antihistamines, antitussives, expectorants/mucolytics, bronchodilators, decongestants and mixtures thereof.
Guaifenesin is known for symptomatic relief of respiratory conditions characterised by dry, non-productive cough and presence of mucus in the respiratory tract. The action of guaifenesin ameliorates dry unproductive cough by decreasing sputum viscosity and difficulty in expectoration and increasing sputum volume. (Ref. Remington The Science and Practice of Pharmacy, 20 Third Ed., p.1303, published by Philadelphia College of Pharmacy and Sciences; herein incorporated by reference). Additionally, it is indicated as a fertility aid in women by thinning mucous endogenous to the reproductive tract.
There are a host of actives that may be combined with guaifenesin. These actives are from suitable classes of agents including, but not limited to the following:
Antihistamines: including, hydroxyzine, pyrilamine, phenindamine, dexchlorpheniramine, clemastine diphenhydramine, azelastine, acrivastine, levocarbastine, mequitazine, astemizole, ebastine, loratadine, cetirizine, terfenadine, promethazine, dimenhydrinate, meclizine, tripelennamine, carbinoxamine, cyproheptadine, azatadine, brompheniramine, triprolidine, cyclizine, thonzylamine, pheniramine, and mixtures thereof.
Antitussives: including, hydrocodone, noscapine, benzonatate, diphenhydramine, chlophedianol, clobutinol, fominoben, glaucine, pholcodine, zipeprol, hydromorphone, carbetapentane, caramiphen, levopropoxyphene, codeine, dextromethorphan, pholcodine and mixtures thereof.
Expectorants/Mucolytics: including, ambroxol, bromhexine, terpin, potassium iodide, n-acetylcysteine, and mixtures thereof.
Bronchodilators: preferably for inhalation, including, albuterol, epinephrine, ephedrine, metaproterenol, terbutaline, theophylline, aminphylline isoetharine, terbutaline, isoetharine, pirbuterol, bitolterol, fenoterol, rimeterol, ipratroprium, and mixtures thereof.
Decongestants: including pseudoephedrine, phenylephrine, phenylpropanolamine and their salts and mixtures thereof.
The level of pharmaceutical actives in the compositions of the present invention is from about 2% to about 40%, alternatively 3% to 40%, and also 5% to 30% of the composition. The level of each active making up the aggregate or combination of the pharmaceutical actives is determinable by one skilled in the art when considering factors including the physicochemical and bioavailability characteristics of the active, the dose regime and the age, weight and physical condition of the patient as well as the stability of the system that incorporates these actives. In regard to this last point, the inventors spent significant effort in working within the confines of present composition's components to determine whether such a system will remains physically stable.
Vehicle
In addition to the actives discussed above, the composition of the present invention comprises a vehicle. The level of the vehicle can be 100% of the composition minus the active and optional ingredients as discussed below. In the present invention, the level of the vehicle in the composition is typically from about 40% to about 98%, alternatively from about 60% to about 90%. The vehicle of the present inventions comprises a three-component mixture of (a) polyoxyalkylene block copolymers, (b) hydrophilic solvents and (c) water, wherein these three components are present in specific proportions to each other. The specific proportions are most readily represented using the ternary (or 3 component) mixture diagram. Such diagrams are well known in the art to described such mixtures; see “Experiments with Mixtures”, John A. Cornell, 1990, John Wiley and Sons, New York, pp. 2–8; herein incorporated by reference. In the case of such mixtures, the total amount of the three components present represents 100% of the vehicle and each component is a proportion of that total amount. The vehicle of the compositions of the present invention may be described precisely using the three-component mixture diagram referred to here as FIG. 1 . The vehicle is defined as region 1 of FIG. 1 , bounded by the lines connecting the vertices of the parallelogram A, B, C and D or segment lines AB, BC, CD and DA.
These vertices are located on the diagram wherein the polyoxyalkylene block copolymer proportions of the is 5% and 25% of the vehicle, hydrophilic solvent portion at 30, 50, 70 and 90% of the vehicle, and water at a portion of 5% and 45% of the vehicle. The vertices of the parallelogram are found at the following 4 points:
Component
polyoxyalkylene
hydrophilic
Total of the
Point
block copolymer
solvent
water
Components
A
5
50
45
100
B
5
90
5
100
C
25
70
5
100
D
25
30
45
100
In determining the percentages of each component comprising the vehicle, the components cannot be varied independently of each other. The proportion of one component depends on the proportion of the other two. For example, if the water proportion falls within the range of 5–45% and the polyoxyalkylene block copolymer falls within the range of 5–25%, the hydrophilic solvent range is determined using the following equation:
100%−(% polyoxyalkylene block copolymer+% water);
In this example, the range is calculated to be from about 30% to about 90%.
Polyoxyalkylene block copolymers, also herein referred to as “poloxamers”, are nonionic block copolymers of ethylene oxide and propylene oxide corresponding to the following structure:
The polyoxyalkylene block copolymers useful in the present invention include those wherein x has a value from about 1 to about 130, y has a value from about 1 to about 72 and x has a value from about 0 to about 130, wherein the average molecular weight of said copolymer is from about 3000 to about 15,000. Alternatively, the polyoxyalkylene block copolymers of the present invention are those where x equals 100, y equals 70 and x′ equals 100 and has an average molecular weight of about 12,600 alternatively where x equals 76, y equals 31 and x′ equals 76 and has an average molecular weight of 8400. The vehicle of the present invention comprises from about 5% to about 25% and alternatively from about 5% to about 20% poloxamer.
The poly (oxyethylene) segment is hydrophilic and the poly (oxypropylene) segment is hydrophobic. Families of poloxamers are available and vary in the number of blocks, the overall average molecular weight, and in the percentage of the molecule which is hydrophilic. A block refers to a single polyoxyethylene or polyoxypropylene segment. Di-block and tri-block polymers have been described. In the case of tri-block copolymers, the blocks can be arranged in the format of one polyoxypropylene block surrounded by 2 polyoxyethylene blocks, that being the most common poloxamer structure, or alternatively as one polyoxyethylene block surrounded by 2 polyoxypropylene blocks, the latter sometimes referred to as a reverse poloxamer. Poloxamers are available under the trade names of Lutrol®, Monolan®, or Pluronic®. The chemical structure, synthesis, and properties have been described as [poly (ethylene oxide)/poly (propylene oxide)] block copolymer surfactants by Paschalis Alexandridis, Current Opinions in Colloid and Interface Science , Vol. 2, pp. 478–489 (1997); herein incorporated by reference.
For health care applications preferable poloxamers include Pluronic® F127, Pluronic® L1220, and Pluronic® F68. These specific polymers are available from BASF Corporation.
In the present invention it is envisioned that combining hydrophilic solvents with the poloxamers and water provides an environment suitable for solubilizing pharmaceutical actives wherein the composition demonstrates the previously discussed physical stability. The vehicle of the present invention comprises from about 30% to about 90%, alternatively from about from about 35% to about 90% and finally from about 40% to about 90% hydrophilic solvents.
The hydrophilic solvents of specific interest are selected from the group consisting of monohydric and polyhydric alcohols. The preferable monohydric alcohols of the present invention include ethanol and tetraglycol. Absolute ethanol is available from Aaper Alcohol & Chemical Co., Shelbyville, Ky. Polyhydric alcohols of the present invention are selected from the group consisting of glycols, monosaccharides, oligosaccharides and mixtures thereof. Glycols are particularly useful as the hydrophilic solvent of the present invention. Glycols used in the present invention are selected from the group consisting of glycerin, propylene glycol and polyethylene glycol. The monosaccharides of the present invention are selected from the group consisting glyceraldehydes, ribose, glucose, fructose, invert sugars (such as honey) and mixtures thereof. The oligosaccharides of the present invention are selected from the group consisting of maltose, sucrose, raffinose, lactose, cellobiose, ribose, sorbitol, mannitol, xylitol, inositol, galactose, mannose, xylose, rhamnose, glutaraldehyde and mixtures thereof.
In addition to the components previously discussed, the present invention comprises water. The level of water in the vehicle of the present invention is from about 5% to about 45%, alternatively from about 5% to about 40%.
Optional Ingredients
The composition can include optional ingredients traditionally included in orally administered liquid compositions, typically to improve the aesthetics of the composition. These optional ingredients include, but are not limited to, dyes, fragrances, preservatives, antioxidants, and similar types of compounds. Specific optional ingredients include, but, are not restricted to surfactants including tyloxapol, polysorbate 80, lauroglycol 90, polyox 40 stearate, capryol 90, polymers including polyvinylpyrrolidone, hydroxypropyl methyl cellulose, beta-cyclodextrins, or solvents, such as propylene carbonate, n-methylpyrrolidone, transcutol, dimethylisosorbide and mixtures thereof. These optional ingredients are included in the composition in an amount sufficient to perform their intended function without compromising the benefits associated with the present invention.
METHODS
Methods for Treating Illness
The delivery of drugs into the bloodstream by placing a dosage form into the mouth can be classified into two major subclasses dependant upon the desired action. In one case where the drug is delivered into the blood by absorption after swallowing (i.e. from the stomach, small intestine or colon) and in the other case where absorption, or at least the significant amount of the absorption occurs through the membranes of the oral cavity either immediately or over extended periods of time when the compositions are retained in the mouth prior to swallowing. This route is generally referred to as “buccal” or “oral mucosal” absorption versus the former route normally referred to as peroral administration of actives. Peroral administration of actives is by far the most commonly used in all of medicine, has been well studied, and is explained in detail in: Mayerson, M., Principles of Drug Absorption; Chapter 2 in “Modem Pharmaceutics”, 2 nd ed., G. S. Banker and C. T. Rhodes, editors, Marcel Dekker Inc., New York, 1990; herein incorporated by reference.
In terms of the methods of delivery of the active, it is generally accepted that oral mucosal delivery inside the mouth is targeted to the sub-lingual region to achieve rapid therapeutic effects; see D. Harris and J. R. Robinson, Drug Delivery via the Mucus Membranes of the Oral Cavity , Journal of Pharmaceutical Sciences 81: 1, 1992. Such dosage forms are delivered under the tongue, on the floor of the mouth, and held there for some extended time. The inventors have found, however, that a large increase in bioavailability with very rapid absorption can be achieved for particular pharmaceutical actives when the subject compositions are placed against any of the mucosal membranes of the mouth, throat, tongue, oropharynx and combinations thereof and swallowed; see PCT Publication 00/41693, Dobrozsi et al., published Jul. 20, 2000; herein incorporated by references.
The form of the invention is a liquid or an elixir intended to be applied to any of the mucosal membranes within the mouth. This can be achieved using a medicine dropper that is calibrated to indicate the proper amount to be administered, and squirting the elixir onto the tongue prior to swallowing. The elixir can be atomized into mouth and throat and then swallowed. It can be encapsulated into some sort of edible and, or chewable shell that makes it portable and convenient to transport and administer without having to measure the quantity of liquid elixir. Examples of encapsulation shells include hard candies as are used for lozenges, gelatin and starch-based shells and combination thereof. The elixir may be packaged into single dose, small, disposable vials easily opened wherein the elixir is squirted or poured into the mouth. Typical dosage forms of the composition of the present invention contain no more than about 3 ml., alternatively from about 0.2 ml. to about 3ml.
Method for Characterizing the Physical Stability of the Present Invention
Susceptibility of changes in morphology and appearance of a composition is indicative of the composition's physical stability. Among the tests to measure this stability is that of measuring the liquid's optical density. This method is thermo-chemical, wherein samples of the compositions and control samples are prepared by the methods as disclosed in the examples below, and packed in 30 ml amber glass bottles leaving a minimal headspace. The bottles were placed in a thermally insulated chamber at a constant temperature of less than 5° C. until being pulled for testing. The OD of the samples including controls and samples of the present invention are evaluated for physical stability by measuring the optical density of each sample. The test is made using a spectrophotometer such as a Jenway Model 6405 UV/VIS, set at a transmittance wavelength of 530 nm. Physical stability is a function of the composition's transmittance of light. The light transmittance of the composition is directly related to the liquids turbidity, sedimentation/precipitation and, or content of crystals found in the liquid.
Measurements of the samples are made at intervals of 7 days. The values are averaged over the entire testing period of 3 months. A formulation with lower optical density values is proposed as having greater overall physical stability. It is required for the composition of the present invention to have Optical Density (OD) value less or equal to 0.05, indicating good physical stability of the composition.
EXAMPLES
Example 1
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 15.39 Dextromethorphan Base 1.13 Propylene Glycol 41.32 Water 20.38 Alcohol, 96% v/v 10.65 Poloxamer 1 7.01 Sucralose 1.40 Flavor 1.50 Sodium Saccharin 0.40 Acesulfame 0.40 Sodium Metabisulfite 0.20 Disodium EDTA 0.20 Monoammonium Glycyrrizinate 0.02 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base and monoammonium glycyrrizinate and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform Subsequently, add desired flavor component and mix until uniform.
Example 2
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 15.39 Dextromethorphan Base 1.13 Propylene Glycol 25.77 Poloxamer 1 15.00 Water 13.59 Alcohol, (100%) 10.00 Transcutol 10.00 Tyloxapol 5.00 Sucralose 1.40 Flavor 1.50 Sodium Saccharin 0.40 Acesulfame 0.40 Sodium Metabisulfite 0.20 Disodium EDTA 0.20 Monoammonium Glycyrrizinate 0.02 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol, tyloxapol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base, transcutol and monoammonium glycyrrhizinate and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently, desired flavor component and mix until uniform.
Example 3
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 15.39 Dextromethorphan Base 1.13 Poloxamer 1 15.56 Water 20.81 Propylene Glycol 34.24 Alcohol, 96% v/v 10.65 Sucralose 0.40 Flavor 1.12 Sodium Saccharin 0.20 Acesulfame 0.10 Sodium Metabisulfite 0.20 Disodium EDTA 0.20 1 Pluronic ® F68 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the water containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring cool and add the alcohol containing premix to the main vessel and continue to mix until uniform Subsequently, add desired flavor component and mix until uniform.
Example 4
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 15.40 Dextromethorphan Base 1.13 Propylene Glycol 27.74 Poloxamer 1 18.52 Water 18.09 Alcohol, (100%) 10.00 Tyloxapol 5.00 Sucralose 1.40 Flavor 1.50 Sodium Saccharin 0.40 Acesulfame 0.40 Sodium Metabisulfite 0.20 Disodium EDTA 0.20 Monoammonium Glycyrrizinate 0.02 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol, tyloxapol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base, and monoammonium glycyrrizinate and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently, desired flavor component and mix until uniform.
Example 5
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 15.40 Dextromethorphan Base 1.13 Propylene Glycol 29.67 Water 17.81 Poloxamer 1 11.87 Alcohol, (100%) 10.00 Transcutol 10.00 Sucralose 1.40 Flavor 1.50 Sodium Saccharin 0.40 Acesulfame 0.40 Sodium Metabisulfite 0.20 Disodium EDTA 0.20 Monoammonium Glycyrrizinate 0.02 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base, transcutol and monoammonium glycyrrizinate and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently, desired flavor component and mix until uniform.
Example 6
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 15.39 Dextromethorphan Base 1.13 Propylene Glycol 52.82 Water 20.38 Alcohol, (96% v/v) 0.44 Poloxamer 1 7.01 Sucralose 0.40 Flavorants 1.12 Sodium Saccharin 0.10 Acesulfame 0.10 Sodium Metabisulfite 0.20 Disodium EDTA 0.91 1 Pluronic ® L1220 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently dissolve the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base, and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the water containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring cool and add the alcohol containing premix to the main vessel and continue to mix until uniform Subsequently, add desired flavor component and mix until uniform.
Example 7
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 15.38 Dextromethorphan Base 1.12 Poloxamer 1 14.00 Propylene Glycol 30.00 Water 17.00 Alcohol, (96% v/v) 10.00 Transcutol 10.00 Flavorants 1.00 Sucralose 0.90 Sodium Saccharin 0.20 Acesulfame 0.20 Sodium Metabisulfite 0.10 Disodium EDTA 0.10 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base, transcutol and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently, desired flavor component and mix until uniform.
Example 8
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 15.39 Dextromethorphan Base 1.13 Tetraglycol 25.25 Propylene Glycol 20.21 Poloxamer 1 14.03 Water 10.00 Alcohol, (96% v/v) 10.65 Sucralose 1.40 Sodium Saccharin 0.44 Acesulfame 0.40 Sodium Metabisulfite 0.10 Disodium EDTA 0.10 Flavorants 0.90 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol, tetraglycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently, desired flavor component and mix until uniform.
Example 9
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 25.00 Dextromethorphan Base 1.83 Poloxamer 1 16.36 Water 20.50 Propylene Glycol 24.34 Alcohol, 96% v/v 10.65 Sucralose 0.40 Flavor 0.40 Sodium Saccharin 0.20 Acesulfame 0.20 Sodium Metabisulfite 0.10 Disodium EDTA 0.02 1 Pluronic ® F68 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform Subsequently, add desired flavor component and mix until uniform.
Example 10
Composition for the Treatment of Cough with an Expectorant
Component % (w/w) Guaifenesin 20.00 Dextromethorphan Base 1.47 Propylene Glycol 19.75 Poloxamer 1 16.07 Water 13.59 Alcohol, (100%) 10.00 Transcutol 10.00 Tetraglycol 5.00 Sucralose 1.40 Flavor 1.52 Sodium Saccharin 0.40 Acesulfame 0.40 Sodium Metabisulfite 0.20 Disodium EDTA 0.20 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol, tetraglycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base, and transcutol and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently, desired flavor component and mix until uniform.
Example 11
Composition for the Treatment of Bronchitis with an Expectorant
Component % (w/w) Guaifenesin 15.26 Ambroxol 2.36 Propylene Glycol 47.27 Water 17.94 Alcohol, 100% 10.00 Poloxamer 1 7.17 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. While stirring add guaifenesin and ambroxol. Once a uniform solution is obtained remove from heat source and continue mixing. Finally, add alcohol and water to the vessel and mix until uniform.
Example 12
Liquid Cough Lozenges
Material % (w/w) Dextromethorphan Base 2.05 Guaifenesin 20.00 Poloxamer 1 15.50 Propylene Glycol 46.71 Water 13.44 Alcohol, (96% v/v) 0.40 Sucralose 0.40 Sodium Saccharin 0.15 Acesulfame 0.15 Sodium Metabisulfite 0.15 Disodium EDTA 0.15 Flavorants 0.90 1 Pluronic ® L1220 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol, and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add guaifenesin continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol, dextromethorphan base and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently add the desired flavor component and mix until uniform. Make individual filled lozenges containing about 1.0 ml. of liquid per lozenge by a commonly used method such as extrusion.
Example 13
Chewable Soft Gelatin Capsules
Component % (w/w) Dextromethorphan Base 2.05 Poloxamer 1 12.25 Propylene Glycol 47.56 Water 10.44 Alcohol, (96% v/v) 10.46 Sucralose 0.40 Sodium Saccharin 0.10 Acesulfame 0.10 Sodium Metabisulfite 0.20 Disodium EDTA 0.15 Guaifenesin 15.39 Flavorants 0.90 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol, and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt and dissolve the poloxamer. Add guaifenesin continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. In a separate vessel (alcohol pre-mix) add alcohol and dextromethorphan base and mix until uniform. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, acesulfame, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer. Mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently, desired flavor component and mix until uniform. Make individual filled soft gelatin capsules containing about 1.0 ml. of liquid
Example 14
Composition for the Treatment of Sinusitis or Symptoms of Allergic Rhinitis
Component % (w/w) Guaifenesin 15.37 Bromhexine 0.67 Propylene Glycol 48.00 Water 18.46 Alcohol, 100% 10.00 Poloxamer 1 7.50 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. While stirring add guaifenesin and bromhexine. Once a uniform solution is obtained remove from heat source and continue mixing. Finally, add alcohol and water to the vessel and mix until uniform.
Example 15
Composition for the Treatment of Bronchitis with Expectorant
Component % (w/w) Guaifenesin 15.37 Bromhexine 0.67 Ambroxol 2.30 Propylene Glycol 46.70 Water 17.46 Poloxamer 1 7.50 Alcohol, 100% 10.00 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. While stirring add guaifenesin, bromhexine and ambroxol. Once a uniform solution is obtained remove from heat source and continue mixing. Finally, add alcohol and water to the vessel and mix until uniform.
Example 16
Composition for the Treatment of Infertility
Component % (w/w) Guaifenesin 18.50 Propylene Glycol 26.75 Poloxamer 1 19.00 Water 16.50 Alcohol, (100%) 10.00 Flavorants 1.40 Tetraglycol 5.00 Sucralose 1.20 Flavor 1.20 Sodium Saccharin 0.25 Sodium Metabisulfite 0.10 Disodium EDTA 0.10 1 Pluronic ® F127 is available from BASF Specialty Chemicals, Mt. Olive, NJ.
Preparation:
Add propylene glycol, tetraglycol and poloxamer to a clean vessel (main mix). While stirring, heat the mixture as appropriate to sufficiently melt the poloxamer. Add Guaifenesin and continue stirring. Once a uniform solution is obtained remove from heat source and continue mixing. Add alcohol and continue mixing. In another vessel (water pre-mix), add water, EDTA, sodium saccharin, sucralose and sodium metabisulfite. Mix until all materials are dissolved.
Add the alcohol containing premix to the main mixing vessel containing the poloxamer mix until uniform. While stirring, add the water containing premix to the main vessel and continue to mix until uniform. Subsequently, desired flavor component and mix until uniform. | The present invention is an orally administered liquid pharmaceutical composition that demonstrates excellent physical stability while delivering concentrated levels of the pharmaceutical active(s). Specifically, these compositions for extended periods do not allow the active to precipitate or settle out of solution. Among the advantages of this invention is that the compositions do not require agitation/shaking prior to use as a method to re-suspend or dissolve active drug material to insure even and consistent dosing. |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional application of U.S. patent application Ser. No. 11/117,285 filed Apr. 29, 2005, now U.S. Pat. No. 7,870,990, the contents of which are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
The invention relates to methods and apparatus for cleaning the hot tip of a soldering iron that do not involve use of water.
DESCRIPTION OF THE PRIOR ART
A soldering iron used to make an electrical or electronic circuit must be cleaned frequently during use. The object is to remove excess molten solder from the tip of the iron and also solder that has become contaminated with burnt residual flux and other materials that impair soldering. Current practice is to wipe the hot tip of the iron against a cellulose sponge soaked with water to avoid burning of the sponge.
Various devices have been proposed in the prior art to implement such a wet cleaning method. A wide-spread practise is to incorporate the sponge into a soldering iron stand. The stand includes a base, a soldering iron holder mounted to the base, and a receptacle in the base for receiving a sponge and water. Other implementations may be found in U.S. Pat. No. 3,990,623 to Fortune; U.S. Pat. No. 4,118,821 to Kuhn; and U.S. Pat. No. 4,803,748 to Quasney.
Other arrangements have been proposed that involve holding the tip of an iron held against dry rotating wiping elements. Examples are to be found in U.S. Pat. No. 3,765,047 to Tashjian; U.S. Pat. No. 4,394,785 to Vogler; and U.S. Pat. No. 4,625,355 to Miyashita. Similar methods and apparatus have also been proposed in Japanese patent JP8192264 to Mizuta et al published on Jul. 30, 1996; German patent DE 4429873 to Kroes published on Mar. 16, 1995; and German patent DE19727181 published on Jul. 2, 1998.
There are significant shortcomings to using a wet sponge to wipe the hot tip of a soldering iron. The principal problem is that the tip cools quickly upon contact with the water-laden sponge. This tends to solidify the molten solder remaining on the tip, and requires the user to wait while the tip to reheats before wiping again. This process may be repeated several times before all solder is removed. Once the tip is clean, the user must wait until the tip is restored to an operating temperature before continuing soldering.
The prior art cleaning method also tends to damage the tip of the soldering iron, impairing application of solder. More specifically, acid residues from solder tend to corrode the tip. As well, use of water in wiping sponges is conducive to build up of salts, especially in areas where local water has a high mineral content. In short order the tip must be replaced.
Despite such shortcomings, the practice of placing a pad of water-laden sponge into a receptacle and wiping the hot tip of a soldering iron against the pad continues.
SUMMARY OF THE INVENTION
In one aspect, the invention provides a method of cleaning molten solder from the hot tip of a soldering iron without use of water. The method involves wiping the hot tip against a dry block of open-celled melamine foam. Such sponge material has been used for household cleaning as it is durable and mildly abrasive. The tip of a soldering iron may typically achieve a temperature of about 450 degrees centigrade, and melamine foam, which has a melting point of about 350 degrees centigrade, can adequately withstand the higher temperature during the brief contact required in normal wiping. Significantly, melamine foam also has the characteristic of becoming more rigid upon application of heat. This is ideal for soldering applications since repeated exposure to a hot iron tends to impart structural rigidity to the surface of the foam, keeping it from falling apart.
Therefore, it is contemplated that various embodiments of the apparatus of the invention may include melamine foam in which at least a first portion of the melamine foam is at least partially more rigid than a second portion of the melamine foam. This rigidity of first portion of the foam may be accomplished through the application of heat or heat and compression to the melamine foam, either during or after manufacture of the foam, for example during the active use of the foam such as by the use of a hot soldering iron on the foam. The second portion of the melamine foam would typically be that which was not exposed to the heat or heat and compression. Examples of such manufacturing processes are described in U.S. Pat. No. 6,608,118 to Kosaka et al. and international application number PCT/US2004/022162 by Goldstein et al., both of which are hereby incorporated by reference. Thus, various embodiments of the invention may also include the method rendering the first portion of the melamine foam more rigid through the application of heat or heat and compression, in combination with other limitations.
A major advantage of using melamine foam is that cleaning time is significantly reduced. Since the tip is not exposed to water, which has a high thermal capacity, the user is not obliged to wait repeatedly for the tip to reheat in order to complete wiping. As well, the user does not have to wait a significant period of time for the tip to restore to an operating temperature before resuming soldering operations.
Another significant advantage of the invention is very effective cleaning. The microcell construction of melamine results in a mildly abrasive cleaning action that removes flux residues very effectively. With prior art methods, fumes potentially hazardous to the user may be seen rising from the tip of the iron, which suggests that contaminants have not be entirely removed. The cleaning method of the invention is sufficiently effective that virtually no noticeable fumes are produced. Since melamine foam is largely free of halides, fibre and CFC's, the foam is also less likely to release toxic substances in response to heat from a soldering iron, particularly since wiping action involves only short contact between iron and foam.
Another advantage of the invention is that the life of the soldering iron tip is extended. One factor is that the method provides very effective removal of acid residues. Another is that the hot tip is not exposed to water so there is no consequent build-up of salts. Since corrosion is reduced, the tip need not be replaced as frequently.
Another advantage of the invention relates to disposal of spent solder that accumulates after repeated cleaning of a soldering iron tip. In the prior art, there has been a tendency to dispose of spent solder beads in a conventional drain, which introduces lead and other toxic materials into local water. Since the method of the invention does not involve a water-laden sponge, there is no need to separate spent solder from water, and users can very conveniently deposit the solder in dry disposal containers.
Other aspects of the invention, including apparatus for implementing the methods of the invention, will be apparent from a description below of a preferred embodiment, and will be more specifically defined in the appended claims. This specification refers to a “through-hole” formed, for example, in a block of melamine foam. For certainty of interpretation, a “through-hole” should be understood as an open-ended passage extending fully between two spaced-apart surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood with reference to drawings illustrating a preferred embodiment, in which:
FIG. 1 is a perspective view of a block of melamine adapted for cleaning of a soldering iron tip;
FIG. 2 is a vertical cross-section of the block of foam of FIG. 1 and a receptacle that retains the block of the foam;
FIG. 3 is a perspective view of another block of melamine foam and a receptacle adapted for cleaning of a soldering iron tip;
FIG. 4 is a perspective view of yet another block of melamine foam adapted for cleaning of a soldering iron tip;
FIG. 5 is a vertical cross-section of the block of melamine foam of FIG. 4 and a receptacle that retains the block of the foam; and,
FIG. 6 is a vertical cross-section of the block of melamine foam and a receptacle which are a variant of the apparatus of FIG. 5 .
DESCRIPTION OF PREFERRED EMBODIMENT
Reference is made to FIGS. 1 and 2 which show a generally rectangular block 10 of dry open-celled melamine foam and a receptacle 12 shaped to retain a lower portion of the block 10 . The block 10 of foam has a funnel-shaped recess 14 in its top surface 16 . The recess 14 has a conical upper portion 18 and a cylindrical lower portion 20 that extends fully to the bottom surface 22 of the block 10 . As apparent in FIG. 2 , a soldering iron 24 is cleaned by wiping the hot tip 26 of the iron 24 against the inclined surfaces of the conical portion 18 of the recess 14 . Molten beads 28 of solder travel along the inclined surfaces of the conical portion 18 into the cylindrical portion 20 of the recess 14 , accumulating at the bottom of the receptacle 12 . When soldering is done, the user can simply invert the block 10 and the receptacle 12 over a dry waste container (not shown) to remove accumulated solder 28 .
FIG. 3 shows alternative apparatus for cleaning the soldering iron tip 26 . Once again, the apparatus includes a generally rectangular block 30 of dry open-celled melamine foam, and a generally rectangular receptacle 32 shaped to receive a lower portion of the block 30 . A cylindrical through-hole 34 with an oval, circular, or other shaped cross-section extends vertically through the block 30 of foam. The user has the option of wiping the tip 26 of the soldering iron 24 along the top surface 36 of the block 30 of foam. Alternatively, the user can insert the tip 26 partially into the through-hole 34 , and then wipe the tip 26 against the upper edge of the through-hole 34 or against the foam surrounding the upper end of the through-hole 34 .
FIGS. 4 and 5 illustrate yet another apparatus for cleaning the tip 26 of the soldering iron 24 . Once again, the apparatus includes a block 38 of dry open-celled melamine foam, and a generally rectangular receptacle 40 for receiving a lower portion of the block 38 .
The block 38 has an overall rectangular shape with a pair of diagonally opposing corners beveled. The block 38 has a parallel pair of opposing side faces 42 (only on side face apparent) that are planar and vertical. The block 38 also has parallel top and bottom surfaces 44 , 46 that are planar and horizontal. The block 38 also has forward and rear faces 50 , 52 . The forward face 50 has a lower surface 54 that is planar and vertical, and an upper surface 56 that is planar and inclined at an acute angle (roughly 45 degrees) relative to the top surface 44 of the block 38 . The rear face 52 has a planar lower surface 58 that is inclined at an acute angle (roughly 45 degrees) relative to the bottom surface 46 of the block 38 and a planar upper surface 60 that is vertical. The lower surface 54 of the forward face 50 and the upper lower of the rear face 52 and are parallel, vertical and spaced for receipt between forward and rear walls 62 , 64 of the receptacle 40 . A cylindrical or other shaped through-hole 66 extends between the upper inclined surface of the forward face 50 and the lower inclined surface of the rear face 52 . The through-hole 66 is inclined at 45 degrees relative to vertical and has open upper end and an open lower end. Other angles for the through-hole are contemplated and are considered within the inventive scope described herein. This symmetry of this arrangement permits the block 38 of foam to be removed from the receptacle 40 , rotated 180 degrees about a central horizontal axis perpendicular to the side faces 42 , and then reinstalled in the receptacle 40 . When rotated, the orientation of the block 38 is identical to its original orientation shown in FIG. 5 . The inclined lower surface 58 of the rear face 52 cooperates with the receptacle 40 to define a space or cavity 68 where solder 28 can accumulate.
In use, the hot tip 26 of the iron 24 is inserted into the upper end of the through-hole 66 and contacted with the foam surrounding the through-hole 66 . As indicated in FIG. 4 , the user then rotates the tip 26 around the interior surfaces of the through-hole 66 to wipe molten solder from the tip 26 . (In FIG. 4 , positions of the soldering iron 24 during such rotation have been shown in phantom outline). The molten solder 28 then travels along the inclined through-hole 66 , escapes through the lower end of the through-hole 66 , and deposits in the space between the receptacle 40 and the inclined lower surface 58 of the rear face 52 . Solder does not cling strongly to the melamine foam; however, should solder accumulate near the upper end of the through-hole 66 , the block 38 can be rotated through 180 degrees relative to the receptacle 40 , and the user can continue soldering and wiping the tip 26 as required. To clean the apparatus, the block 38 of foam is simply removed, and the debris accumulated in the cavity 68 can simply be dumped into a dry disposal container. Any solder clinging to the foam surrounding the through-hole 66 can be dislodged with a finger.
FIG. 6 shows a variation of the apparatus of FIGS. 4 and 5 . Common reference numerals have been used to indicate features common to the two apparatus. The principal difference resides in the configuration of the shape of their respective through-holes. The apparatus of FIG. 6 has a through-hole 70 with an upper frustoconical portion 72 and a lower frustoconical portion 74 . Each frustoconical portion 72 or 74 expands progressively from the center of the block 38 to the inclined surfaces between which the through-hole 70 extends. This arrangement permits the user to keep the conical tip 26 of the soldering iron 24 substantially normal to the entrance opening of the through-hole 70 . More specifically, limited wrist action is required to wipe the conical surface of tip 26 against the conical inner surfaces that define the conical passage portions 72 , 74 . Beads 28 of solder forming against those surfaces travel along the inclined trough 76 of the upper passage portion 72 and accumulate in the cavity 68 .
It will be appreciated that particular embodiments of the invention have been described and that modifications may be made therein without necessarily departing from the scope of the appended claims.
PARTS LIST
Cleaning Soldering Iron Tip
FIGS. 1 and 2
10 block
12 receptacle
14 funnel-shaped recess
16 top surface (block)
18 upper conical portion
20 lower cylindrical portion
22 bottom surface (block)
24 soldering iron
26 hot tip
28 beads of solder
FIG. 3
30 block
32 receptacle
34 through-hole
36 top surface (block)
FIGS. 4 and 5
38 block
40 receptacle
42 side faces
44 top surface
46 bottom surface
48 (not used)
50 forward face
52 rear face
54 lower surface (forward face—vertical)
56 upper surface (forward face—inclined)
58 lower surface (rear face—inclined)
60 upper surface (rear face—vertical:)
62 forward wall (receptacle)
64 rear wall (receptacle)
66 through-hole
68 cavity (accumulating solder)
FIG. 6
70 through-hole
72 upper frustoconical portion (through-hole)
74 lower frustoconical portion (through-hole)
76 trough (through-hole) | In one aspect the invention provides a method of cleaning molten solder from the hot tip of a soldering iron that does not require a water-laden sponge. The hot tip of the iron is wiped against a block of dry open-celled melamine foam. The block is formed with an inclined through-hole that leads to the bottom of a receptacle holding the block. The hot tip is wiped against the foam surrounding an upper end of the through-hole, and the molten solder removed from the tip accumulates in the receptacle below. |
RELATED APPLICATION
[0001] This is a continuation of International Application No. PCT/FR01/01353, with an international filing date of May 5, 2001, which is based on French Patent Application No. 00/05650, filed May 3, 2000.
FIELD OF THE INVENTION
[0002] This invention pertains to a means for maintaining the security of a substrate, and in particular a means for maintaining the security of banknotes or financial documents.
BACKGROUND
[0003] Known in the state of the art are means for maintaining security formed by narrow strips presenting an easily recognizable and verifiable visual appearance and limiting the risks of counterfeiting.
[0004] As an example, EP 229645 describes a process for creating a security paper comprising a security element incorporated in the paper in the form of a thread or a strip. The security element is situated at least locally in the thinnest regions of the paper or on the surface of the paper.
[0005] A first paper layer is formed by a first wet part of a paper machine, which is detached from the metal netting by means of a gripper band. A second layer of paper is formed on a second wet part of a paper machine. One or both of the two layers of paper have at least local regions that are thinner, representing up to 30% of the total thickness of the two layers of paper.
[0006] In order to improve this process of the prior art, U.S. Pat. No. 4,943,093 proposes creation of a security paper and a security device placed between the two surfaces of the paper as a characteristic of public security, comprising a flexible substrate with a metal layer on one surface of the substrate. The security device, which has a width smaller than 5 mm, is positioned at least partially between the surfaces of the paper. A continuous metallic track is present on at least one side of the device along its entire length. The device has demetallized parts which are permeable to light and which comprise between 10 and 50% of the surface of the device. The parts without metal placed along the length of the device form a pattern, a design or repetitive marks.
[0007] It would therefore be advantageous to further reinforce the security of such solutions by providing a security means that is easy to implement and difficult to counterfeit.
SUMMARY OF THE INVENTION
[0008] This invention relates to an apparatus for maintaining security of a substrate having an optically verifiable mark including a partially demetallized metallic layer which forms a control graphic, a layer of optically active pigments adjacent the metallic layer, and an adhesive layer adjacent the layer of optically active pigments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Better understanding of the invention will be obtained from reading the description below of a nonlimitative example of implementation with reference to the attached drawings in which:
[0010] [0010]FIG. 1 is a cross-sectional view of an element according to aspects of the invention;
[0011] [0011]FIG. 2 is a schematic perspective view of a first variant of implementation; and
[0012] [0012]FIG. 3 is a schematic perspective view of a second variant of implementation.
DETAILED DESCRIPTION
[0013] This invention pertains to a means for maintaining the security of a substrate constituted of an optically verifiable mark comprising a partially demetallized metallic layer and an adhesive layer, characterized in that it comprises an intercalary layer comprising optically active pigments.
[0014] According to a first variant, it has an additional layer formed by a stamped varnish. According to a second variant, it is coated by a polyester film deposited on a detachment layer.
[0015] The optically active pigments are advantageously constituted of: heat-sensitive pigments, luminescent pigments, triboluminescent pigments, iridescent pigments, and/or photoluminescent pigments excitable by ultraviolet radiation.
[0016] According to one particular mode of implementation, the security-maintenance means according to the invention has an alternation of optically active pigments of different types. It is preferably implemented in the form of a narrow spool.
[0017] Turning now to the drawings, FIG. 1 represents a cross-sectional view of an element according to the invention. The marking element is formed by a bottom adhesive layer ( 1 ) for adhering onto the substrate, for example, a sheet of paper. Layer ( 1 ) is covered by a pigmented layer ( 2 ) on which is deposited alternating metallized zones ( 3 ) and demetallized zones ( 4 ). An optional layer ( 5 ) formed by a stamped varnish constitutes a transparent hologram. Layer ( 5 ) is covered by a detachment layer ( 6 ) and a polyester film ( 7 ).
[0018] The pigmented layer ( 2 ) comprises optically active pigments producing effects that are easy to observe visually, but difficult to reproduce, for example, pigments the color of which varies in relation to the temperature, incident light, orientation, gravity, under the effect of rubbing and the like.
[0019] The element according to the invention is manufactured by printing a metallic layer on the polyester preparation surface ( 7 ), for example, by vacuum deposition, and by partial demetallization of the thereby created layer. Demetallization can be implemented by a chemical bath, for example. On the layer formed by an alternation of metallized zones and demetallized zones is then deposited the pigmented layer creating recognizable patterns. Preparation is terminated by depositing an adhesive layer ( 1 ).
[0020] [0020]FIGS. 2 and 3 represent two examples of particular implementations.
[0021] The security element is provided in the form of a narrow strip enabling placement of a marking track on a substrate. This track has an overall metallized appearance with demetallized windows ( 10 ) forming patterns recognizable by their non-shiny appearance.
[0022] The track can also have an alternating zones ( 11 ) comprising iridescent pigment(s) superposed on the metallized zones, zones ( 12 ) having heat-sensitive pigment(s) and zones ( 13 ) having UV sensitive pigment(s).
[0023] The track can be applied by simple adhesion on a substrate to provide this substrate with a particular, easily controllable optical behavior.
[0024] This makes it possible to simplify the manufacture of substrates that are secure against fraud and falsification, while making it highly difficult to counterfeit because of the combination of optical effects which are difficult to analyze and even more difficult to reproduce. | An apparatus for maintaining security of a substrate having an optically verifiable mark including a partially demetallized metallic layer which forms a control graphic, a layer of optically active pigments adjacent the metallic layer, and an adhesive layer adjacent the layer of optically active pigments. |
FIELD
This disclosure pertains generally to solvent-recovery systems that utilize distillation or a related technique to convert a solvent, in a mixture including the solvent, into a vapor that is condensed and recovered in purer form than in the mixture. More specifically, the disclosure pertains to evaporator vessels used for containing a solvent mixture while the mixture is being distilled, and to solvent-distillation apparatus including such evaporator vessels.
BACKGROUND
The use of solvents in various cleaning operations remains widespread, despite increasingly strict environmental regulations concerning the use and/or release into the environment of certain types of solvents. For example, organic solvents (including halogenated solvents) are used extensively for cleaning machined parts during manufacture of the parts. Organic solvents also are used extensively for cleaning parts, such as engine parts and other parts from motor vehicles, during repair or refurbishment operations of such vehicles. In fact, use of an organic solvent is frequently the only practical way in which to remove grease, sludge, varnish, and similar deposits from many types of parts.
Not only are the costs of organic solvents continuing to increase, but certain specific solvents are increasingly the subject of strict governmental regulation in terms of the conditions under which the solvents can be used and in terms of disposal of the solvents. Certain solvents (such as halogenated solvents) have become regulated so intensively that many prior uses of such solvents have become curtailed substantially.
As a result of situations as summarized above, in many instances it is most practical for a user of a cleaning solvent simply to recover and purify (i.e., “recycle”), on site, the solvent that has become laden with solutes as a result of using the solvent for cleaning purposes. In this regard, distillation of the solute-laden solvent mixture is a favored solvent-recycling and -recovery method because distillation can be performed using a compact apparatus that can be installed almost anywhere. As is well known, distillation typically involves heating a liquid solvent-containing mixture in an evaporator vessel (also termed the “pot”) to produce a vapor of substantially only the solvent (disregarding formation of azeotropes). The solvent vapor is conducted to a condenser that converts the vapor into a corresponding liquid. Because mostly solvent vapor is released from the liquid mixture in the pot, substantially all of the solute is left behind in the pot, and the condensed liquid usually is substantially purer with respect to the solvent than the liquid remaining in the pot.
Distillation is well known as a purification technique for any of various solvents, including water. The many types of distillation systems disclosed in the art have various respective features that reportedly improve the utility, efficiency, and/or applicability of the technique for particular conditions of use. Depending upon the particular configuration or condition of use of the distillation system, certain parameters may or may not have substantial importance.
For example, solvent-distillation apparatus are used in automotive repair shops and the like where the removal of grease, oil, sludge, and the like from parts is a critical aspect of the repair business. Advantageously, such solvent-distillation apparatus are compact in size, energy-efficient, safe to use (including under conditions in which personnel are not present), and reliable. An example of such an apparatus is disclosed in U.S. Pat. No. 4,929,312 to the current Applicant. Similar to many other types of distillation apparatus, the apparatus disclosed in the '312 patent includes an evaporation vessel (“pot”) made of metal and configured to contain a solvent liquid to be distilled. The pot includes a heating unit that heats the liquid in the pot sufficiently (typically to boiling) for production of solvent vapor for distillation. The solvent vapor passes from the pot to a condensing unit that cools the vapor to a liquid (comprising purified solvent) that is collected for re-use.
It has been discovered that a key performance criterion for a distillation system, such as the system disclosed in the '312 patent, is an ability to sense the temperature of the liquid in the pot accurately and in real time. In the apparatus of the '312 patent, the heating unit is embedded in a thick mass of metal (e.g., aluminum) at the bottom of the pot. The temperature of the liquid in the pot is sensed, for control purposes, by a thermostatic switch attached to a side wall of the pot or to the mass of metal at the bottom of the pot. With the thermostatic switch at either location, a substantial amount of heat energy must be applied to the metal of the pot to cause a significant change in temperature as sensed by the thermostatic switch. As a result, especially under conditions of temperature change, the temperature sensed by the thermostatic switch does not accurately track in real time the actual temperature of the liquid in the pot. For example, consider a thermostatic switch situated such that the heating unit is between the thermostatic switch and the inside wall of the pot. With this configuration the temperature sensed by the thermostatic switch may lead or not lead, depending upon whether the heating unit is energized or not energized. Also, the resulting dampening of temperature sensing allows substantial swings in temperature of the liquid to occur without being sensed at all by the thermostatic switch. Consequently, safe and efficient operation of the apparatus can be compromised.
SUMMARY
The deficiencies of conventional systems as summarized above are satisfied by vaporization chambers and vessels as disclosed herein, as well as by distillation systems comprising such chambers and vessels.
According to a first aspect of the instant disclosure, vaporization vessels (“distillation pots”) are disclosed that comprise walls including a heated wall and a cover that collectively define an interior space. A liquid is contained in the interior space as the liquid is being heated in the pot for a distillation purpose. The pot includes a plate configured and situated in the interior space so as to divide the space into an upper portion and a lower portion that hydraulically communicate with each other by an upper fluid passageway and a lower fluid passageway defined by the plate. A thermally conductive member extends from a location on an inside surface of a wall into the liquid. The thermally conductive member is configured to be contacted by the liquid whenever the pot contains liquid being heated for distillation. The thermally conductive member also serves as a direct thermal connection from the liquid to a corresponding location outside the wall, adjacent the location on the inside surface, at which the temperature of the liquid in the pot can be sensed. The thermally conductive member extends into the lower fluid passageway so as to contact and be at the temperature of the liquid passing through the lower fluid passageway. As the liquid is being heated in the pot, the liquid circulates from the lower portion through the upper fluid passageway to the upper portion, and from the upper portion through the lower fluid passageway past the thermally conductive member to the lower portion.
Desirably, the heated wall is located in the lower portion, and the thermally conductive member extends into the lower portion. In this configuration, as the liquid is heated in the lower portion, the liquid contacts the thermally conductive member.
The upper fluid passageway can be configured so as to define a reflux vent extending from the lower portion and that opens into the upper portion. Bubbles passing through the upper fluid passageway from the lower portion break in the upper portion to release entrained liquid that drains into the lower portion through the lower fluid passageway. In a more specific embodiment in which the heated wall is located in the lower portion, bubbles formed in the liquid in the lower portion can be guided by the plate to the reflux vent. The bubbles travel up the reflux vent to the upper portion where the bubbles release entrained liquid for circulation through the lower fluid passageway and past the thermally conductive member to the lower portion. Desirably, the bubbles are propelled from the reflux vent against the inside surface of the cover, thereby releasing the entrained liquid.
Another embodiment of a distillation pot comprises walls, including a heated wall, and a cover that collectively define an interior space in which a liquid is contained as the liquid is being heated in the pot. The pot includes a reflux plate that is configured and situated in the interior space so as to have a vertical portion and a sloped portion including a lower end and a higher end. The sloped portion has peripheral edges between the higher and lower ends. The pot also includes a thermally conductive member extending from a location on an inside surface of a wall into the liquid. The thermally conductive member is configured so as to be contacted by the liquid whenever the pot contains liquid being heated for distillation and to serve as a direct thermal connection from the liquid to a corresponding location outside the wall, adjacent the location on the inside surface, at which the temperature of the liquid in the pot can be sensed. The peripheral edges of the sloped portion are sealingly attached to respective inside surfaces of the walls so as to divide the interior space into an upper portion and a lower portion (in which the heated wall is located) that communicate with each other via the higher end and the lower end. The vertical portion extends upward from the higher end relative to a respective inside surface of a wall so as to define a reflux vent between the vertical portion and the respective inside surface. The reflux vent opens in the interior space beneath the cover to provide the communication from the lower portion to the upper portion. The lower end extends, with an intervening clearance, around the thermally conductive member, wherein the clearance is sufficient to provide the communication from the upper portion to the lower portion such that, as the liquid is being heated in the pot, bubbles formed in the liquid in the lower portion are guided by the sloped portion to the reflux vent, rise up the reflux vent, and are propelled from the reflux vent against the inside surface of the cover. As the bubbles impact the inside surface, they break and release entrained liquid for passage through the clearance to below the reflux plate.
The distillation pot can comprise a heater in thermal contact with the heated wall. The heated wall can be, for example, the bottom wall of the pot. The pot further can comprise a thermal sensor (e.g., a thermostatic switch) in thermal contact with the corresponding location outside the wall.
Desirably, the inside surface of the heated wall defines at least one vane situated and configured to provide thermal transfer from the heated wall to the liquid in the lower portion. The lower portion can include a bottom surface defining a drain port that slopes toward a drain port defined in a wall of the lower portion.
In the pot the clearance desirably is situated and configured such that that, as the liquid flows through the clearance from the upper portion to the lower portion, the liquid flows past the thermally conductive member while contacting the thermally conductive member. The thermally conductive member desirably has a fin-like configuration extending toward a center of the pot, wherein the fin-like configuration provides a high ratio of surface area to volume. For example, the ratio can be at least 20.
The distillation pot also desirably has a vapor outlet. In certain of the embodiments summarized above, the vapor outlet is situated on an opposite side of the pot from the reflux vent. Desirably, the vapor outlet is defined in the cover.
The distillation pot further can comprise a control valve hydraulically connected to a supply of liquid for distillation in the pot. In this embodiment the control valve comprises a level-sensing or analogous mechanism that is responsive to the liquid level in the pot so as to add liquid from the supply to the pot for distillation whenever the liquid in the pot is below a pre-determined level. By way of example the level-sensing mechanism can be a float assembly, wherein the float assembly is situated in the upper portion.
According to another embodiment, a distillation pot comprises wall means, including heated wall means, and cover means that collectively define an enclosed interior space in which a liquid is contained as the liquid is being heated in the pot for a distillation purpose. The pot includes interior-space-dividing means for dividing the interior space into an upper portion and a lower portion that hydraulically communicate with each other by an upper fluid-passageway means and a lower fluid-passageway means. The pot further includes thermal-conduction means that extends from a location on an inside surface of a wall means into the liquid and is configured so as to be contacted by the liquid whenever liquid is in the interior space and is being heated for distillation and to serve as a direct thermal connection from the liquid to a corresponding location outside the wall means, adjacent the location on the inside surface, at which the temperature of the liquid in the pot can be sensed. The thermal-conduction means desirably extends into the lower portion and lower fluid-passageway means so as to contact and be at the temperature of the liquid passing through the lower fluid-passageway means. As the liquid is being heated in the pot, the liquid circulates from the lower portion through the upper fluid-passageway means to the upper portion, and from the upper portion through the lower fluid-passageway means past the thermal-conduction means to the lower portion.
According to another aspect, distillation systems are disclosed. An embodiment of such a system comprises a distillation pot such as any of the embodiments summarized above. The distillation system also includes a condensing unit that is situated relative to the pot so as to receive vapor produced by heating of the liquid in the pot and that is configured to condense the vapor to a corresponding liquid. The system further can comprise a heater in thermal contact with the heated surface of the pot. The system further can comprise a thermostatic switch or analogous appliance that is in thermal contact with the thermally conductive member. The thermostatic switch can be used, for example, for controlling operation of the heater. The pot also desirably includes a vapor outlet situated in an upper location of the pot and a conduit hydraulically connecting the vapor outlet to the condensing unit.
Another aspect of the disclosure is set forth in the context of a distillation method in which a liquid, contained in a distillation pot, is heated in the pot to produce a corresponding vapor that is condensed to form a distillate. This aspect is directed to methods for heating and controlling the temperature of the liquid in the distillation pot. An embodiment of such a method comprises the step of heating the liquid in a lower portion of the pot while guiding circulation of the liquid to an upper portion through an upper fluid passageway between the lower and upper portions. In the upper portion, circulation of the liquid in the upper portion is guided through a lower fluid passageway, between the upper and lower portions, to the lower portion. During circulation of the liquid through the lower fluid passageway, the liquid is caused to flow past a thermally conductive member situated so as to contact the liquid in the lower fluid passageway and in the lower portion. Heat energy is conducted from the liquid directly, via the thermally conductive member, to a location outside the pot, where the temperature of the location is sensed.
The sensing step desirably is performed using a thermal sensor that produces thermal data concerning the liquid in the lower portion and lower fluid passageway. This embodiment further can comprise the step of controlling, based on the thermal data, an amount of heat energy applied to the liquid in the pot during the heating step.
The method further can comprise the step of removing foam from the liquid in the upper portion. According to one embodiment, this foam-removal step comprises guiding bubbles, formed in the liquid in the lower portion, from the lower portion through the upper fluid passageway to impinge on an inside surface of a wall of the upper portion with sufficient force to fracture the bubbles. In the upper portion, entrained liquid released from the fractured bubbles is collected. The collected entrained liquid is circulated from the upper portion through the lower fluid passageway to the lower portion.
Another method embodiment comprises heating the liquid in a lower portion of a distillation pot while guiding bubbles, formed in the heated liquid, into an inlet of a reflux vent having an outlet situated above the inlet. The bubbles are moved up the reflux vent so as to cause the bubbles to be expelled from the outlet of the reflux vent onto a surface on which the bubbles fracture to release liquid entrained in the bubbles. The liquid released from the fractured bubbles is combined with liquid in an upper portion of the pot. Liquid is flowed from the upper portion to the lower portion through a fluid passage so as to replace the liquid from the lower portion carried, as entrained liquid, up the reflux vent. In the fluid passage, the liquid is flowed by, and thus is made to contact, the thermally conductive member extending from a wall of the pot. Heat energy is conducted from the liquid directly, via the thermally conductive member, through the wall of the pot to a thermal sensor situated outside the pot. Based on thermal data produced by the thermal sensor, a distillation parameter of the liquid in the pot during the heating step is controlled. The distillation parameter can be, for example, an amount of thermal energy applied to the liquid in the pot during the heating step.
Yet another method embodiment is directed to a method for heating a liquid in a vessel so as to convert the liquid into a vapor. According to an exemplary embodiment, heat is applied to a “heated wall” (desirably located in a lower portion of the vessel) to heat the liquid. While applying the heat, circulation is imparted to a fluid stream of the liquid from the lower portion to an upper portion of the vessel to release the vapor, and from the upper portion back to the lower portion. In the fluid stream from the upper portion to the lower portion, the fluid is caused to flow past a thermally conductive member situated so as to contact the liquid in the stream and in the lower portion. Heat energy is conducted from the liquid directly, via the thermally conductive member, through the vessel wall to a location outside the vessel. The temperature of the thermally conductive member is sensed outside the vessel wall.
The foregoing and additional features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a representative embodiment of a distillation system that includes a vaporization chamber (“pot”) as disclosed herein, wherein the pot is shown in section to reveal some interior detail.
FIG. 2 is an oblique view, in section, of a representative embodiment of a vaporization chamber (“pot”), including a reflux plate and thermally conductive member as described herein.
FIGS. 3(A)-3(E) are orthogonal views of the pot embodiment shown in FIG. 2 , but not showing the reflux plate, wherein FIGS. 3(A)-3(C) are respective elevational views, FIG. 3(D) is a top plan view showing interior detail of vanes, and FIG. 3(E) is a bottom view showing external detail of the heater-element gland.
FIG. 3(F) is an orthogonal section along the line A-A in FIG. 3(E) .
DETAILED DESCRIPTION
Certain aspects of an exemplary solvent-distillation system 10 are described below, referring to FIG. 1 . The system 10 includes a chamber 11 configured to contain a supply of solvent 12 used for degreasing parts and for related uses. For such degreasing, the parts can be immersed directly in the solvent 12 in the chamber 11 , or the chamber 11 can be provided with a pump, conduit, and nozzle (not shown) that discharge a stream of solvent from the chamber to a part held in the chamber such that grease- or oil-laden solvent drains from the part back into the chamber 11 . Further alternatively, solvent can be removed from the chamber 11 , used for cleaning at a remote location, and then returned to the chamber 11 . The chamber 11 has an outlet 14 used for draining solvent 12 from the chamber as required. The outlet 14 is connected via a conduit 20 to an inlet 26 of an evaporator vessel (“pot”) 24 . The bottom 28 of the pot 24 is in thermal contact with a heater 30 (e.g., an electrical-resistance type) or analogous appliance that heats the liquid contained in the pot 24 for distillation purposes, as described later below.
Hence, the pot 24 usually contains a volume of solute-laden solvent delivered to the pot 24 from the chamber 12 . To maintain a desired level of liquid within the pot 24 , the inlet 26 is provided with a control valve 32 comprising a float assembly 36 including a buoyant member 38 that rises upwardly with increases in liquid volume in the pot 24 . Whenever the solvent reaches a selected level, the control valve 32 and buoyant member 38 cooperate to close the inlet 26 .
The pot 24 has a removable cover 40 that, in the depicted embodiment, includes a vapor outlet 39 to which a conduit 44 is connected that conducts vapor from the pot 24 to a condensing unit 46 . The condensing unit 46 includes a heat exchanger 48 . For example, the heat exchanger 48 is air-cooled with multiple cooling fins 50 and a motor-driven blower 54 that propels a stream of air over the cooling fins 50 . Alternatively, the heat-exchanger 48 is liquid-cooled (not shown).
Connected to the heat exchanger 48 via a conduit 60 is an inlet 61 of a secondary accumulator 62 . An outlet 66 of the secondary accumulator 62 is connected via a conduit 64 to an inlet 72 of a primary accumulator 76 . Flow of condensate through the conduit 64 is controlled by a pressure-sensitive check valve 70 . Adjacent the conduit 64 is a conduit 78 that leads from a port 74 in the primary accumulator 76 into a pressure-evacuation system including a vacuum transducer 80 . The vacuum transducer 80 controls the flow of compressed air into and out of the distillation system 10 , and employs a venturi to create a subatmospheric pressure in selected regions of the system 10 , as described later below. The vacuum transducer 80 is connected to a solenoid valve 82 (or analogous automatically actuatable valve) that includes an inlet port 84 for receiving air from a conventional compressed source, and an outlet port 85 . The solenoid valve 82 is connected to a timer 86 that operates the vacuum transducer 80 in a cyclical manner, as described later below. Whenever the solenoid valve 82 is actuated, compressed air from the source passes from the inlet port 84 through the solenoid valve to the outlet port 85 . The vacuum transducer 80 includes a port 90 through which air flows into and out of the system 10 as desired. Adjacent the port 90 is an inlet 92 for receiving compressed air from the outlet port 85 of the solenoid valve 82 . The compressed air is used by the vacuum transducer 80 to create a subatmospheric pressure in selected locations inside the system 10 .
Leading from an outlet 94 in the primary accumulator 76 is a conduit 96 that terminates at the top 98 of the chamber 11 . Provided at the end of the conduit 96 is a pressure-sensitive check valve 100 similar to the check valve 70 .
A disposal system allows elimination of solute sludge (oil, grease, and the like) that has accumulated in the pot 24 from distilling off the solvent. An outlet 102 is provided adjacent the heater 30 , which communicates with a conduit 104 leading into a waste-accumulation tank 106 or other suitable repository. The conduit 104 can include a valve 103 that can be manual or automatic. The conduit 104 can terminate with a pressure-sensitive check valve 108 (of the same type as the check valve 70 ). Either or both valves 103 , 108 control the draining of sludge from the pot 24 into the waste-accumulation tank 106 . As described in more detail later below, situated with respect to the pot 24 is a thermostatic switch 110 that communicates through wires or analogous connections with a solenoid valve 116 (or analogous automatically actuatable valve). The solenoid valve 116 has an inlet 118 and an outlet 120 connected via a conduit 124 into the conduit 44 .
The distillation system 10 operates in a timed cycle, in which contaminated solvent 12 in the chamber 11 is routed to the pot 24 from which solvent is evaporated, and the resulting vapor of purified solvent is condensed and collected for re-use. Operational timing of the system 10 is controlled by appropriately setting the timer 86 , which governs the time duration in which the system is “on” and whether certain components such as the heater 30 are on at times that are appropriate and safe. Turning the system 10 on in this manner actuates the solenoid valve 82 , which supplies compressed air to the vacuum transducer 80 through the inlet 92 of the vacuum transducer. As a result, a subatmospheric pressure is created that that opens the check valve 70 , allows air to be aspirated from the system through the port 90 , and establishes a subatmospheric pressure in the pot 24 , the conduit 44 , the condensing unit 46 , and the accumulators 62 , 76 . The subatmospheric pressure also seats the check valve 100 , which prevents air from entering the system 10 from the chamber 11 .
Due to the subatmospheric pressure in the pot 24 , contaminated solvent is drawn from the chamber 11 through the conduit 20 into the pot 24 . Solvent continues to flow into the pot 24 through the inlet 26 until the buoyant member 38 reaches a pre-selected level at which the control valve 32 closes the inlet 26 and thus shuts off flow of additional solvent into the pot 24 .
Then, the heater 30 is activated (turned on), thereby initiating heating and causing vaporization of the solvent in the pot 24 under the subatmospheric conditions previously established in the pot. The subatmospheric pressure aids vaporization of the solvent in the pot 24 . To achieve proper vaporization, the temperature of the heater 30 is adjusted according to the type of solvent in the pot 24 . The vaporized solvent travels upward through the vapor outlet 39 in the cover 40 of the pot 24 , through the conduit 44 , and into the condensing unit 46 , in which the vapor is condensed to a liquid. The condensed liquid (now a purified solvent) passes through the conduit 60 , through the secondary accumulator 62 and check valve 70 , and into the primary accumulator 76 in which the purified liquid solvent is stored temporarily.
Whenever the timer 86 cycles to “off,” the solenoid valve 82 stops delivery of compressed air to the inlet 92 of the vacuum transducer 80 . As a result, the vacuum transducer 80 no longer generates a subatmospheric pressure, and air flows into the system 10 through the port 90 , restoring the primary accumulator 76 to atmospheric pressure. Meanwhile, the check valve 70 seats and maintains a subatmospheric pressure in the system upstream of the check valve 70 . This subatmospheric pressure permits the system 10 to continue operating while the purified solvent in the primary accumulator 76 drains into the secondary accumulator 62 for temporary storage (due to the check valve 70 remaining seated).
Simultaneously with the seating of the check valve 70 , the check valve 100 opens as atmospheric pressure is established inside the primary accumulator 76 . This allows purified solvent in the primary accumulator 76 to flow through the conduit 96 back into the chamber 11 for reuse. When a subatmospheric pressure again is generated in the system 10 by the vacuum transducer 80 , the check valve 100 seats as the check valve 70 opens, causing purified solvent temporarily stored in the secondary accumulator 62 to drain into the primary accumulator 76 . The system 10 then repeats the pattern of operation described above.
As the system 10 continues to operate, waste solute (grease, oil, and the like) and other contaminants left behind in the pot 24 tend to accumulate as sludge in the pot 24 . Removal of this accumulated sludge at the appropriate time is facilitated by setting the thermostatic switch 110 at an appropriate pre-selected temperature. (The temperature of the liquid in the pot 24 tends to increase as the percentage of sludge (solute) in the pot increases.) Upon reaching the pre-selected temperature, the thermostatic switch 110 turns off the heater 30 and activates the solenoid valve 116 , thereby allowing entry of atmospheric air through the inlet 118 . The air passes through the outlet 120 , the conduit 124 , the conduit 44 , the cover 40 , and into the pot 24 . As a result, pressure is increased within the pot 24 , which opens the check valve 108 and allows the sludge to pass from the pot 24 through the outlet 102 in the bottom 28 of the pot 24 . The sludge passes through the conduit 104 , through the check valve 108 , and into the tank 106 for disposal.
As discussed earlier above, the conduit 104 or outlet 102 can be provided with an on-off valve 103 actuated by an operator, e.g., after confirming that the temperature of the sludge in the pot has cooled to a safe level. For example, an apparatus fitted with a pot 24 having a 6-quart capacity can be configured to initiate drainage of the pot whenever the volume of accumulated sludge in the pot reaches about 2 quarts. As discussed elsewhere herein, the thermostatic switch 110 can be configured to turn the heater 30 off whenever an excessive sludge volume has accumulated in the pot (wherein the heater 30 remains off until the thermostatic switch 110 is reset by the operator). The user then drains the sludge from the pot 24 through the valve 103 when the temperature of the liquid in the pot drops to a temperature (e.g., 150° F., as sensed by a thermometer discussed later below) at which the pot can be drained safely. Draining of the pot 24 is facilitated by venting the pot, as described above, through the inlet 118 .
The manual on-off valve 103 can be replaced with an automatic, temperature-actuated on-off valve, such as a temperature-actuated solenoid valve, configured to open automatically for drainage of the pot 24 after the liquid in the pot has cooled to a safe temperature. Draining of liquid from the pot while the heater remains off results in a substantial decrease in temperature as sensed by the thermostatic switch 110 . After the pot 24 has cooled to a suitably low temperature, the thermostatic switch 110 in the FIG.- 1 embodiment deactivates the solenoid valve 116 . The heater 30 can be activated either automatically or upon a confirmation (either automatic or manual) that the pot 24 has been filled with more liquid to be distilled.
During operation, as noted above, the heater 30 heats the liquid in the pot 24 sufficiently to produce copious amounts of solvent vapor from the liquid for the purpose of distillation. Typically, adequate vapor production is achieved during actual boiling of the liquid in the pot 24 under subatmospheric pressure (which facilitates boiling of the solvent at a lower temperature than if boiling were performed at atmospheric pressure). During boiling of the liquid in the pot 24 , many bubbles of solvent vapor are formed rapidly, rise to the surface of the liquid, and break to release the vapor. The vapor rises (again, as facilitated by the subatmospheric pressure) through the conduit 44 to the condensing unit 46 . Under such conditions, especially if the liquid in the pot 24 contains certain solutes or a large amount of dissolved solutes in general, excess foam is produced. If the pot 24 has a conventional configuration (and especially if the pot is compact in configuration), this foam can be difficult to control and/or to prevent from accumulating sufficiently to propagate up to the condensing unit 46 . However, pots within the scope of the current disclosure are resistant to excess foaming and also provide more accurate and efficient sensing of the temperature of the liquid in the pot.
A representative embodiment of a pot 24 is depicted in FIG. 2 and FIGS. 3(A)-3(F) , in which the pot 24 has side walls 130 and a “bottom” wall 131 desirably made as a single unit, such as by casting. The pot 24 desirably is made of a material that can be cast or molded easily (such as an aluminum alloy, cast iron, or other suitable metal) and that exhibits acceptably good thermal conductivity. As discussed above, in this embodiment a heater 30 is situated adjacent (“below”) and in thermal contact with the bottom wall 131 . The side walls 130 terminate with a flange 134 used for attaching (using screws or analogous fasteners) the cover 40 to the pot 24 , thereby enclosing the pot 24 and defining an interior space 138 inside the pot 24 . In the interior space 138 the solvent mixture to be distilled is contained as the mixture is being heated by the heater 30 . Vapor produced by the heating rises in the pot 24 and passes from the pot to the condensing unit 46 via the conduit 44 , as discussed above.
In the depicted embodiment in which the heater 30 is situated “below” the bottom wall 131 , the heater 30 is nested in a gland 129 defined on the outer surface of the bottom wall 131 . Extending upward from the inside surface of the bottom wall 131 are multiple vanes 133 , baffles, or the like that facilitate turbulence of the liquid in the pot 24 as the liquid is being boiled by the heater 30 . The vanes 133 , and the fluid-turbulence they generate, provide substantially more efficient (compared to a pot lacking the vanes) thermal transfer from the bottom wall 131 (as heated by the heater 30 ) to the liquid contained in the pot, and prevent thermal stratification of the liquid. The depicted number, size, and orientations of the vanes 133 (see especially FIG. 3(D) ) are not intended to be limiting. These parameters can be selected and optimized readily as prevailing conditions indicate.
In general, the vanes 133 extend from the “heated” wall of the pot 24 . In the depicted embodiment (FIGS. 2 and 3 (A)- 3 (F)), the heated wall is the bottom wall 131 . However, this configuration is not intended to be limiting. In certain embodiments, it is desirable to heat the pot 24 from a wall other than, or in addition to, the bottom wall 131 (e.g., the side wall 130 ). In these other embodiments, vanes 133 can extend from the side wall in addition to the bottom wall or instead of from the bottom wall.
To control the disposition of and limit accumulation of foam bubbles in the pot 24 , the pot is provided with a reflux plate 140 that, as mounted in the pot, has a “vertical” portion 142 and a sloped portion 144 . The sloped portion 144 has a “lower” end 136 , a “higher” end 137 , and peripheral edges extending therebetween. As suggested in FIG. 2 , the reflux plate 140 can be secured to the pot 24 by screws or analogous fasteners that extend through respective holes 156 in the sloped portion 144 and thread into or otherwise are attached to respective vanes 133 , for example (see holes 157 in FIG. 3(D) ). The sloped portion 144 extends nearly circumferentially (except for the higher and lower ends of the sloped portion) around the inside diameter of the pot 24 . To facilitate establishment of a substantial seal between the peripheral edges and the inside surfaces of facing side walls 130 , the periphery of the sloped portion 144 rests on and desirably is sealed to a shoulder 145 extending nearly circumferentially around the side walls 130 . “Seal” is used here in a comparative sense, and does not necessarily denote establishment of a seal of hermetic integrity. Rather, the seal ensures that bubbles, formed in the liquid beneath the reflux plate, do not flow around the peripheral edges of the sloped portion (that are attached to the side wall) to the liquid above the reflux plate. The seal can be achieved using a suitable gasket 147 (e.g., an O-ring seated in a gland 149 defined in the shoulder 145 ). Alternatively, the seal can be achieved by, e.g., seating the peripheral edges of the sloped portion 144 into appropriately configured respective receptacles (not shown) in the shoulder 145 or extending around the inside surface of the side wall 130 .
The lower end 136 of the sloped portion 144 is not sealed (as discussed later below) to the side wall 130 , which allows liquid to drain from “above” the sloped portion 144 to “below” the reflux plate 140 . During use the pot 24 is filled with solvent mixture to a level desirably approximately at the higher end 137 of the sloped portion 144 (see FIG. 1 ). Thus, some of the liquid in the pot is located above the reflux plate 140 , and other liquid is located beneath the reflux plate 140 . The vertical portion 142 of the reflux plate 140 extends “upward” from the higher end 137 . The vertical portion 142 defines, along with the adjacent inside surface 146 of the side wall 130 , an in-pot “reflux vent” or “foam chimney” 143 . (“Vertical” is used here in an approximate sense; the vertical portion 142 need not be absolutely vertical, but rather sufficiently upwardly extending to function satisfactorily as a reflux vent.) Specifically, foam formed beneath the reflux plate 140 does not pass, to any significant extent, around the peripheral edges of the reflux plate. Rather, the foam is urged to travel beneath the sloped portion toward the reflux vent 143 and up the reflux vent toward the cover 40 . The distal end of the vertical portion 142 is just beneath the adjacent inside surface of the cover 40 . Thus, as the foam travels up the reflux vent 143 , the bubbles are propelled against the inside surface of the cover 40 with sufficient force to fracture most of the bubbles. The entrained liquid released from the fractured bubbles drains back into the pool of liquid in the pot and is recirculated (as described below) to the liquid beneath the reflux plate 140 .
Referring to FIG. 1 , the control valve 32 desirably is mounted in a manner allowing the float assembly 36 to be located “above” the reflux plate 140 . This allows an unrestrained range of vertical movement of the buoyant member 38 with normal fill volumes of the pot 24 and facilitates filling of the pot with the desired volume of solvent mixture to be distilled.
By way of example, the reflux plate 140 is made of sheet steel, sheet aluminum or other suitable metal, sheet polymeric material (preferably fiber-reinforced) or sheet composite material that is inert to the solvent, solutes, vapor, and operating temperature of the pot 24 . Similarly, the cover 40 can be made of aluminum, steel, polymeric material (e.g., glass-reinforced nylon), or composite material that is suitably inert from a chemical and thermal standpoint to the conditions of use. The pot typically is mounted by legs 135 or analogous features to a platform or the like (not shown) in the distillation system 110 .
The shape of the pot 24 desirably is substantially cylindrical as shown (for ease of fabrication), but it alternatively can be any other suitable shape as required or desired. By way of example, for use in distillation systems suitably sized for use in an automotive garage or similar facility, the pot 24 has an interior volume of approximately six quarts, wherein the pot normally is kept filled with approximately two quarts of solvent for distillation purposes. (Maintenance of this fill level is achieved using the control valve 32 and float assembly 36 , as discussed above.) A pot 24 having such a size and made of cast aluminum has an exemplary wall thickness of 3/16 to ¼ inch.
The bottom wall 131 of the pot 24 desirably is sloped (e.g., 5° from the horizontal, see FIG. 3(A) ) downward to the outlet 102 to facilitate complete draining of liquid from the pot when desired. The sloped portion 144 of the reflux plate 140 desirably is sloped approximately 15° upward from the horizontal, toward the reflux vent 143 . During boiling, many bubbles of vapor are formed in the liquid beneath the reflux plate 140 . As the bubbles rise in the liquid, the sloped portion 144 effectively directs the bubbles toward the reflux vent 143 . The bubbles rise up the reflux vent 143 and impact the inside surface of the cover 40 , which breaks the bubbles and thus prevents accumulation of excess foam in the pot 24 . The vapor outlet 39 ( FIG. 1 ) desirably is situated on the opposite side of the pot from the reflux vent 143 to inhibit incursion of any foam bubbles into the conduit 44 . (As an alternative to being located on the cover 40 , the vapor outlet 39 can be located at an upper portion of a side wall 130 , on the opposite side of the pot 24 from the reflux vent 143 .)
The lower end 136 of the sloped portion 144 extends around (but does not contact or seal against) a thermally conductive (“TC”) member 148 (having a fin shape in this embodiment). In the depicted embodiment the TC member 148 is attached to and extends upward from the bottom wall 131 of the pot 24 ( FIG. 2 ) and is attached to and extends radially inward from an adjacent side wall 152 of the pot. (Attachment of the TC member 148 to wall(s) in this manner is facilitated by simply casting the member as part of the pot 24 .) Note that the thermostatic switch 110 is mounted to the outside surface of the side wall 130 immediately opposite the location on the inside surface of the side wall from which the TC member extends. This provides the shortest and most direct thermal connection from the liquid to the thermostatic switch (or other thermal sensor). Hence, in the depicted embodiment, whereas the TC member is attached to the bottom wall 131 for convenience in casting, this attachment is not necessary so long as the TC member, in its manner of attachment to a wall, provides the shortest possible thermal conduit to the thermostatic switch.
Also desirably, the TC member has a fin-like shape (for maximal surface-area contact with the liquid in the pot) and extends radially toward the center of the pot 24 (to form the shortest possible thermal conduit from the liquid to the thermal sensor). By way of example, in a pot 24 defining an interior volume of approximately six quarts, the TC member 148 has a height of approximately two inches, a width of approximately one inch, a thickness of approximately ⅛ inch, and a clearance 150 from the low end of the reflux plate 140 of approximately 3/16 inch. The top of the TC member 148 desirably is at approximately the normal level of liquid in the pot 24 .
A clearance 150 is defined between the TC member 148 and the lower end 136 of the reflux plate 140 . During boiling of the liquid in the pot 24 , the clearance 150 , the sloped portion 144 of the reflux plate 140 , and the reflux vent 143 facilitate rapid circulation of fluid in the pot. Specifically, the bubbles moving along the under-surface of the sloped portion 144 and up the reflux vent 143 carry a significant amount of entrained liquid. As the bubbles break against the cover 40 , the entrained liquid returns to the liquid above the reflux plate 140 . To replace entrained liquid carried from below the reflux plate by the bubbles, liquid passes from above the reflux plate 140 through the clearance 150 to below the reflux plate. This liquid circulation is rapid and always flows immediately past the TC member. As a result, the temperature of the TC member 148 is maintained at the actual temperature of the liquid in the pot 24 , even if that temperature is changing.
As noted above, the TC member 148 desirably has a relatively thin, fin-like shape, which is effective for maximizing its surface area while minimizing its mass. In FIG. 2 the TC member 148 is shown as including a cylindrical portion 150 , but it will be understood that the cylindrical portion 150 is not necessary for proper functioning of the TC member. Rather, the cylindrical portion 150 simply facilitates removal of the pot 24 from a casting die if the pot 24 is made of cast metal. In any event, the fin-like profile of the TC member 148 (see exemplary dimensions above) provides it with an appropriately low “thermal inertia,” by which is meant that the TC member 148 rapidly reaches the current temperature of the liquid or the like with which the TC member 148 is in contact. By way of example, a TC member 148 made of aluminum desirably has a surface-to-volume ratio of at least 20. The dimensions of the TC member 148 typically are not dictated to any significant extent by the particular type of solvent contained in the pot 24 but rather by the need to achieve, via the TC member 148 , the lowest possible temperature gradient between the liquid in the pot and the thermostatic switch 110 (or other thermal sensor so located) under actual-use conditions.
In the depicted embodiment, attached to the adjacent side wall 154 on a surface opposite the TC member 148 and outside the pot 24 is the thermostatic switch 110 . An exemplary thermostatic switch 110 is any of the “60T” Series of temperature controls manufactured by Therm-O-Disc, Mansfield, Ohio. The TC member 148 establishes a direct thermal conduit from the liquid to the thermostatic switch 110 for accurate sensing of the temperature of the liquid. In other words, the TC member 148 (and intervening wall thickness between the TC member and thermostatic switch) functions as a thermal conduit (“heat pipe”) from the liquid in the pot to the thermostatic switch 110 . Also, the flow of liquid past the TC member 148 is turbulent and thus does not exhibit thermal stratification. Consequently, the temperature sensed by the thermostatic switch 110 is the temperature of the TC member 148 , which is the temperature of the liquid in contact with it. Also, by thus locating the thermostatic switch 110 so as to receive thermal input directly from the TC member 148 rather than the temperature of the bottom wall 131 of the pot, as in conventional distillation systems, temperature sensing and control can be performed in substantially real time.
Extending in association with the bottom wall 131 (e.g., along the lower surface 158 of the bottom wall 131 ) in the depicted embodiment is a thermometer 160 (e.g., model POC-1, manufactured by Ametek U.S. Gauge, Feasterville, Pa.). The depicted thermometer 160 comprises a probe shaft 162 that extends toward the center of the bottom surface 131 through a corresponding radially extending bore 164 in the bottom surface. The thermometer 160 can be used generally for obtaining a temperature reading of the liquid contained in the pot 24 . More specifically, as discussed earlier above, the temperature of the liquid in the pot 24 tends to increase during boiling conditions as the relative concentration of solute in the liquid increases (as it inevitably does over time). Using the thermometer 160 , the operator can obtain a direct reading of liquid temperature for determining suitable times for draining solute sludge from the pot 24 (e.g., draining the pot only after the liquid inside has cooled to a relatively “safe” temperature of approximately 150°). (The thermostatic switch 110 can be set so as to turn the heater off at the moment the liquid in the pot reaches a temperature indicating time to drain the pot.) The thermometer 160 also is useful for providing a reading of pot temperature before filling the pot with more liquid to be distilled.
By way of example, the heater 30 is rated at 120 Vac, 600 W, and is manufactured by Watlow Electric Manufacturing Co., St. Louis, Mo.
Whereas the invention has been described above in connection with a preferred embodiment, the invention is not limited to that embodiment. On the contrary, the invention is intended to encompass all modifications, alternatives, and equivalents as may be included within the spirit and scope of the invention, as defined by the appended claims. | Vaporization chambers (distillation "pots") are disclosed in which the liquid contained in such a pot is heated and circulated to establish thermal uniformity of the liquid and to route the circulated liquid past a thermally conductive member that contacts the liquid. The thermally conductive member extends from a location on a wall of the pot in a portion of the pot that holds the liquid as the liquid is being heated in the pot and conducts thermal energy directly from the liquid to a location outside the pot corresponding to the location on the wall. The pot desirably is divided into an upper portion and lower portion, wherein the liquid circulates from the lower portion to the upper portion and from the upper portion to the lower portion during heating. During this circulation, bubbles formed in the liquid can be routed into the upper portion in a manner resulting in fracture of the bubbles and recovery of liquid entrained in the bubbles, thereby preventing foam accumulation in the pot. |
BACKGROUND OF THE INVENTION
The present invention pertains in general to a method and apparatus for splitting flow and in particular to a method and apparatus for splitting the flow of a vapor-liquid mixture.
In oil fields where steam is injected into a formation as part of an enhanced oil recovery (EOR) program, it is important to know the quantity and quality (ratio of steam to water) of steam being injected into each of a plurality of wells. Planning an injection program for each well and evaluating its effectiveness require a knowledge of conditions in each well. Implementing an effective EOR program requires the ability to control the quality and quantity of steam delivered to each well.
Although the quantity of steam applied to each well may be effectively controlled by valves or chokes, it is difficult to obtain a desired quality for each of a plurality of injection wells from a single steam source. When the flow of steam is split, different amounts of liquid water might flow into each of the split branches of the flow.
To predictably split the flow of a liquid-vapor mixture, one approach involves providing an inlet at the top of a vessel having a plurality of outlet pipes projecting upward through the bottom of the vessel to equal heights, as found for example in U.S. Pat. Nos. 3,899,000, 4,140,178 and 4,293,025. A splash baffle between the inlet and outlet pipes prevents substantially all liquid in the flow from falling directly into the outlet pipes. The liquid accumulates in the vessel and enters the outlet pipes by spilling over the lip of the open end of each outlet pipe or through holes bored in the side of each outlet pipe. One drawback to this approach is that it removes virtually all liquid from the flow so that a large vessel is required at a correspondingly large cost. Another drawback is that in order to accommodate the outlet pipes, the vessel may have to be specially made, particularly in the larger sizes, because large enough vessels having the required wall thickness for use with steam are not readily available.
Another approach, exemplified by U.S. Pat. No. 4,396,063, passes the mixture to be split through a motionless mixer in order to homogenize the liquid and vapor phases and then immediately passes the mixture against a blade in a "wye" conduit. This approach has the disadvantages of requiring the use of non-standard equipment and of assuming that liquid that drops out at the wye will be re-entrained in the flow in equal amounts down each branch.
Absent from either approach is the ability to inexpensively and reliably divide a flowing liquid-vapor mixture into streams of substantially equal quality.
SUMMARY OF THE INVENTION
Accordingly, the present invention involves apparatus for splitting a liquid-vapor mixture into a plurality of streams or for adjusting the liquid-vapor ratio by liquid removal. The apparatus comprises a reservoir having at least one side wall defining n apertures of equal size, n>1. The apertures are at a common gravitational potential. Each of the apertures is symmetrically distributed at 360/n degrees about the circumference of the reservoir. The reservoir has a top defining an opening above and equally distant from each of the apertures. The reservoir also has a bottom. Each of the plurality of outlet pipes terminate at one of the apertures and an inlet has an open end communicating with the reservoir through the opening in the top of the reservoir.
A method of splitting a liquid-vapor mixture into a plurality of streams according to the present invention comprises the step of: providing a reservoir having at least one sidewall defining n apertures of equal size and at a common gravitational potential, n>1, each of the apertures being symmetrically distributed at every 360/n degrees about the circumference of the reservoir, the reservoir having a top defining an inlet opening above and equally distant from each of the apertures, the reservoir having a bottom; a plurality of outlets, each pipe being coupled to one of the apertures; and an inlet having an open end communicating with the reservoir through the opening in said top of the reservoir. The method also comprises the step of introducing steam a liquid-vapor mixture through the inlet opening.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a view in partial section of a first embodiment of the present invention;
FIG. 2 is a view in horizontal cross-section of the apparatus of FIG. 1 along line 2;
FIG. 3 is a block diagram of a system for controlling steam quality and quantity according to the present invention; and
FIG. 4 is a view in partial section of a second embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In a first embodiment of the apparatus according to the present invention as illustrated in FIG. 1, the reservoir 10 has a hollow cylindrical center portion 12. Reservoir 10 is positioned so that arrow 11 points in a vertical direction.
Above and below cylindrical portion 12, hollow conical portions 14 and 15 are respectively connected at their widest points to hollow cylindrical portion 12. At an upper end of hollow conical portion 14, a hollow cylindrical inlet 16 is connected by way of a hollow cylindrical lip 18 and a hollow conical portion 20 to a hollow cylindrical inlet flange 22. Similarly, beneath hollow conical portion 15 is a hollow cylindrical inlet 17. Inlet 17 is sequentially connected by way of a hollow cylindrical lid 19 and a hollow conical portion 21 to a hollow cylindrical drain flange 23.
Elements 18, 20 and 22 make up inlet 24 while elements 19, 21 and 23 form drain 25. The connection between cylindrical portions 16 and 18 forms an inlet opening. Similarly, the connection between cylindrical portions 17 and 19 forms a drain opening.
Four outlets, 30, 32, 34 and 36 (not shown), are symmetrically distributed in a level plane, i.e., at a common gravitational potential, about the middle of central portion 12. Each inlet is composed of a flange connected to a wide end of a first hollow conical portion which is in turn connected to a narrow end of a second hollow conical portion, the wide end of which is connected to cylindrical portion 12.
As shown in FIG. 2, wherein elements also illustrated in FIG. 1 are identified by the same reference numerals which are used to identify them therein, the four outlets 30, 32, 34 and 36, are symmetrically distributed at every 90° about the circumference of reservoir 10. Outlet 30 has a flange 38 connected to a first conical portion 40 which is in turn connected to a second conical portion 42. Outlet 32 has a flange 44 connected to a first conical portion 46 which is in turn connected to a second conical portion 48. Similarly, outlet 34 has a flange 50 connected to a first conical portion 52 which is in turn connected to a second conical portion 54. Outlet 36 has a flange 56 connected to a first conical portion 58 which is in turn connected to a second conical portion 60.
Reservoir 10 has a sidewall 70 which has circular apertures of equal size, 72, 74, 76 and 78, to which internal cavities of the second conical portions of outlets 30, 32, 34 and 36 are respectively connected.
As shown in FIG. 3, inlet 24 is connected by way of a pipe to a steam generator 112. Outlets 30, 32, 34 and 36 are respectively connected to pipes leading to steam injection wells 182, 184, 186 and 188 at which it is desirable to have an equal quality or quantity of steam by way of valves 172, 174, 176 and 178 respectively. Drain 25 is connected by way of a turbine meter 100 to a valve 110 which is in turn connected to a pipe leading to a water disposal apparatus 111.
Valve 110 is used to maintain the liquid level substantially near the bottom of the outlets at which point changes in the valve setting allow for control of the amount of water removed from or retained in the steam. For example, a given flow of water may be permitted to pass out of reservoir 10 through valve 110 in order to provide for a given amount of water to leave reservoir 10 by way of the outlets. Likewise, the valve may be fully opened in order to remove as much water as possible from the steam.
Toward the end of monitoring the water level in reservoir 10, particularly in order to ensure that all water is removed, a first nipple may be installed above the level of the outlets, a second nipple may be installed below the level of the outlets and a level indicating meter 120 installed between the two nipples. An optical reader 140 may be installed in association with the level indicator to provide data to automatic monitoring equipment 160. Monitoring equipment 160 may comprise a computer and is connected to valves 110, 172, 174, 176 and 178.
The quality of steam at injection wells 182, 184, 186 and 188 may be raised by transmitting a signal from equipment 160 to open valve 110 and thereby decreasing the fraction of water in the mixture at the outlets. Meter 100 is connected to equipment 100 and a signal from it confirms a change in flow out of drain 25. A flowrate indicative of a desired quality level may be determined through known methods of calculation and calibration.
Flow meters 192, 194, 196 and 198 are respectively connected between valve 172 and well 182, between valves 174 and well 184, between valve 176 and well 186 and between valve 178 and well 188. Each of these meters is connected to equipment 160 and provides an output signal indicative of the flow rate of steam entering each well to equipment 160. Equipment 160 opens or closes valves 172, 174, 176 and 178 to adjust the flow rate and, hence, the quantity of steam provided to the corresponding wells. Because the same quality of steam is provided to each well through splitter 8, and because the quantity of steam provided to each well is adjusted by way of valves 172, 174, 176 and 178, planning and implementing a desired EOR program by controlling both steam quality and quantity is facilitated.
In order to be most effective, the length and diameter of pipe should be the same between splitter 8 and each of wells 182, 184, 186 and 188. Secondary flow splitters may be used to further divide the streams from outlets 30, 32, 34 and 36. Maintaining the equality of length and diameter of pipe from a secondary splitter to each well it feeds also promotes equal quality among the wells. Each secondary splitter may be placed between the primary splitter and the valves controlling the quantity of steam to each of the wells it feeds.
As indicated in FIG. 1, when splitter 8 is in use, steam enters apparatus 8 by passing directly downward in the direction of arrow 80 through inlet 24 and into reservoir 10. Within reservoir 10, water drops out of the steam. The water collects at the bottom of reservoir 10 above drain 25 until it reaches level 90, which is at the same height as the lower edge of each of apertures 72, 74, 76 and 78. When water reaches level 90, it flows into outlets 30, 32, 34 and 36 in equal proportions, because these outlets are at the same level and apertures 72, 74, 76 and 78 are the same size. This water flowing into the outlets is re-entrained with substantially equal portions of steam so that streams of the liquid-vapor mixture having substantially equal quantity and quality flow through outlets 30, 32, 34 and 36 in the direction of arrows 82, 84, 86 and 88, respectively.
As illustrated in FIG. 4, wherein elements which also appear in FIGS. 1 and 2 are identified by the same reference numerals as used therein, an alternative embodiment of the flow splitter according to the present invention is referenced by numeral 8' to indicate a different embodiment. A cylindrical pipe 300 has a first end 301 welded to portion 14 about its internal circumference. A second end 302 of pipe 301 is located below the level of the lowest point of outlets 30, 32, 34 and 36 and preferably below an expected water level in reservoir 10. Pipe 300 is perforated by a plurality of holes below its first end 301 and above both the uppermost point of outlets 30, 32, 34 and 36. Pipe 300 directs liquid water to a point below the level of the outlets, which promotes even splitting at least in part by preventing an annular flow from passing directly through splitter 8 to the outlets, and breaks up waves in water collected at the bottom of reservoir 10, which prevents waves from sloshing over unequally into the outlets.
All of the elements of apparatus 8 and 8' are readily constructed by one skilled in the art from metal parts and fittings of the sort commonly manufactured for use in piping systems. For example, because reservoir 10 may be narrower than those vessels where outlet pipes pass through the bottom, reservoir 10 may be made from readily available pipe rather than having to be specially cast. For example, the internal diameter of reservoir 10 may be twice that of inlet 24.
The dimensions of apparatus 8 may be varied to suit particular applications, but certain general guidelines may be provided. Within limits, the larger the portion of reservoir 12 above the outlets, the better liquid drops out of the liquid-vapor mixture. Placing the outlets a distance of 2 or more times the diameter of reservoir 12 below the inlet also promotes the dropping out of the liquid.
Monitoring equipment 160 may comprise any suitable control apparatus, such as indicators, manual controls and electronic devices.
Although apparatus 8 has been described in terms of splitting a mixture of water and steam, the apparatus according to the present invention may be advantageously employed with other liquid-vapor mixtures (or gas-liquid or gas-liquid vapor mixtures where a vapor is distinguished from a gas as being close to a liquid state or containing liquid particles), as is readily understood by one skilled in the art. Likewise, although four outlets are shown in the preferred embodiment, it is clear to one skilled in the art that any number of symmetrically distributed apertures may be employed where n is the number of apertures and where the apertures are spaced at every 360/n degrees about the circumference of the reservoir 12. It is also clear to one skilled in the art that reservoir 12 need not be cylindrical but may be of any symmetrical shape which provides substantially equivalent environments for each of the outlets. For example, a nipple may be installed in sidewall 70 of reservoir 8 or 8'. This nipple may be used to treat the water collected in reservoir 8 or 8' with treatment materials such as salts or corrosion inhibitors. Similarly, the nipple may be used to sample the water for the purpose of analysis.
While the present invention has been described in terms of the preferred embodiment, further modifications and improvements will occur to one skilled in the art.
I desire it to be understood, therefore, that this invention is not limited to the particular form shown and that I intend in the appended claims to cover all such improvements and variations which come within the scope of the invention as claimed. | A flow splitter for liquid-vapor mixtures wherein a reservoir has an inlet at a top end and a drain at a bottom end of a vertical axis, and also has a plurality of outlets in a level plane perpendicular to the vertical axis. Each inlet is connected by an equally sized aperture in a sidewall of the reservoir to a central cavity of the reservoir in which the liquid collects. When the liquid accumulates to the point that it reaches the lower edge of each aperture, the liquid divides equally among the apertures to become re-entrained with a substantially equal portion of the vapor passing through each outlet. The liquid may be removed through the drain to control the proportion of liquid in the split mixture. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] (Not Applicable)
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
[0002] (Not Applicable)
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX
[0003] (Not Applicable)
BACKGROUND OF THE INVENTION
[0004] This invention pertains to an assembly of modular objects for autonomously executing a variety of tasks. Such an assembly is sometimes referred to as a robot—“a machine or mechanical device that operates automatically with humanlike skill.” The Random House College Dictionary, Revised Edition, Random House, Inc., New York, N.Y. (1988).
[0005] Present-day robots are designed to perform specialized tasks such as vacuuming a carpeted room, mowing a lawn, storing and retrieving goods in warehouses, obtaining and delivering goods in the course of manufacturing operations, and performing operations in connection with the making of parts and the assembly of machines. Specialized designs of robots for the performance of specialized tasks will be an insurmountable economic burden to the widespread use of robots in the future unless a way is found to design robots to perform a multitude of tasks utilizing the same basic configuration.
BRIEF SUMMARY OF THE INVENTION
[0006] The invention is a modular assembly of modular objects for autonomously executing a variety of tasks. The modular assembly consists of a modular object called a platform, one or more modular objects called modules which are mounted to the platform in accordance with a modular assembly system, and a modular bus system for distributing electrical power and electrical signals among the modular objects in the modular assembly. The modular assembly system utilizes modular object fasteners (MOFs) and MOF-accommodating features of modular objects for facilitating the attachment of a plurality of modular objects to one another thereby creating a modular assembly in any one of a variety of configurations, an MOF being activatable when object attachment surfaces associated with two modular objects are superimposed and two object attachment points on the object attachment surfaces coincide.
[0007] The modular assembly system facilitates the detachment of modular objects in an assembly and the reattachment of the same or different modular objects to form a different configuration of the modular assembly or a different modular assembly.
[0008] The modular object called a platform consists of a frame of interconnected beams and any cross-members attached to the frame, the frame being amenable to the attachment and detachment of cross-members within the frame. Beams and cross-members are structural members consisting of one or more parallel flanges and one or more webs normal to the flanges. Coplanar exterior surfaces of the flanges of the beams and cross-members constitute object attachment surfaces with object attachment points thereon. The web surfaces of the beams and cross-members constitute bus attachment surfaces.
[0009] One or more modular objects called modules having at least one object attachment surface is attachable to a platform or to another module when one or more of the object attachment points on an object attachment surface of the module coincide with one or more object attachment points on an object attachment surface of the platform or the other module;
[0010] The modular bus system consists of modular-object bus systems attached to one or more bus-attachment surfaces within each modular object, one or more inter-object bus connectors for electrically connecting the plurality of modular-object bus systems to one another, and one or more intra-object bus connectors for enabling the flow of electrical power and electrical signals between the bus system of a modular object and the units within the modular object.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] FIG. 1 is a three-dimensional view of a modular assembly.
[0012] FIG. 2 is a three-dimensional view of a frame for a modular assembly.
[0013] FIG. 3 is a plan view of a platform for a modular assembly consisting of a frame and cross-members.
[0014] FIG. 4 shows the arrangement of holes in the frame and cross-members of a platform which provides the basis for the assembly of the platform and the attachment of modules to the platform.
[0015] FIG. 5 shows how an I-shaped cross-member fits into a channel-shaped frame.
[0016] FIG. 6 shows a sectional view of a cross-member attached to a frame in a plane normal to the cross-member.
[0017] FIG. 7 shows a sectional view of a cross-member attached to a frame in the plane of the web of the cross-member.
[0018] FIG. 8 shows a view of the electrical bus that is attached to interior surfaces of the frame and cross-members for the transmission of power and control signals among modules.
[0019] FIG. 9 shows a sectional view of the bus of FIG. 8 .
[0020] FIG. 10 shows a sectional view of how a cross-member bus is connected to a frame bus.
[0021] FIG. 11 is a three-dimensional view of the cross-member bus connector which connects a cross-member bus to another cross-member bus or to the frame bus.
[0022] FIG. 12 is a three-dimensional view of the corner bus connector utilized in connecting the frame buses at the corners of the frame.
[0023] FIG. 13 is a top view of a frame corner showing how the corner bus connector attaches to the frame and makes contact with the frame buses.
[0024] FIG. 14 is a front view of the corner bus connector shown in FIG. 13 .
[0025] FIG. 15 shows a module in position to be attached to a platform.
[0026] FIG. 16 shows a module in position to be attached to another module.
[0027] FIG. 17 shows a pivoting bus connector used to electrically connect the platform bus to a module bus.
[0028] FIG. 18 is a view of the fingers of a corner bus connector used to connect module buses.
[0029] FIG. 19 is a plan view of a corner bus connector used to connect module buses.
[0030] FIG. 20 is a sectional view of a corner bus connector in position to be installed in the corner of a module.
[0031] FIG. 21 is a sectional view of a bus which may be used as either a frame bus or a junction bus.
[0032] FIG. 22 is a sectional view of a module bus.
[0033] FIG. 23 is a perspective view of the fingers of a junction bus connector.
[0034] FIG. 24 is a perspective view of a junction bus connector.
[0035] FIG. 25 shows a junction bus termination connected to a junction bus which is connected to a module bus.
[0036] FIG. 26 shows how a junction bus connector attaches to a module bus.
[0037] FIG. 27 is a perspective view of the junction bus termination.
[0038] FIG. 28 shows how a junction bus connector is held in position against a module wall by the pivoting bus connector frame.
[0039] FIG. 29 shows the pivoting bus connector in the parked position.
[0040] FIG. 30 shows the pivoting bus connector in the connected position.
[0041] FIG. 31 shows how the conductors in the pivoting bus connector are transitioned from a linear configuration to a square configuration.
[0042] FIG. 32 shows how the conductors in the pivoting bus connector are transitioned from a square configuration to a linear configuration.
[0043] FIG. 33 is a perspective view of the yoke of the pivoting bus connector.
[0044] FIG. 34 is a perspective view of the pivoting bus connector fingers.
[0045] FIG. 35 shows how the pivoting bus connector connects to a module bus.
[0046] FIG. 36 is a perspective view of the bus connector utilized in connecting electronic devices and circuits within a module to the module bus system.
[0047] FIG. 37 is a plan view of a module floor and the opening through which the pivoting bus connector moves in connecting to the frame or another module.
[0048] FIG. 38 shows how a dust-free environment is maintained in a module after a pivoting bus connector connects the bus system of the module to the bus system of the frame or another module.
DETAILED DESCRIPTION OF THE INVENTION
[0049] The invention is a modular assembly comprising a platform and a variety of modules which can easily be attached to and detached from the platform thereby permitting a user to easily put together a modular assembly to perform a particular task or a variety of tasks by the appropriate selection of modules.
[0050] A simple example of the preferred embodiment of the invention is shown in FIG. 1 . It consists of platform 11 , power module 13 , navigation module 15 , guidance & control module 17 , four mobility modules 19 (three of which are shown in the figure), and task module 21 . A modular assembly may not need to move in order to perform its assigned tasks, in which case there would be no need for mobility modules. In some situations one might want to exercise overall control of the modular assembly with an external controller which would communicate with the modular assembly by means of wires or wirelessly.
[0051] Power module 13 supplies all of the power required by the modules. Depending on the power requirements of the modular assembly, it might be simply a storage battery or a hybrid arrangement of storage batteries and a generator driven by an internal combustion engine. If a variety of AC and DC voltages are required by the modules, then power module 13 would also include appropriate inventers and converters.
[0052] Navigation module 15 continually determines the position and velocity of the modular assembly and supplies this data to guidance & control module 17 which in turn generates control data for the mobility modules 19 which will cause the assembly to follow the path appropriate for performing the tasks assigned to the modular assembly.
[0053] Each of the mobility modules 19 consists of an independently-suspended caster which utilizes separate electric motors to control the caster direction and the caster wheel rotation rate. The mobility modules 19 are mounted on the bottom of the platform in contrast to the top mounting of the other modules. The mobility modules are of the caster type and can be confined to the region immediately below the platform 11 as shown in the figure. However, there is no requirement that any of the modules must be confined to the regions either immediately above or below the platform. If the mobility modules are based on an automotive-type suspension, the wheels associated with the mobility modules will necessarily be outside of the platform perimeter.
[0054] The platform consists of a frame of interconnected beams where a beam is a structural member designed to resist bending. The component parts of a beam are one or more parallel flanges connected together by one or more webs normal to and attached to the flanges. In applications where the beams are to resist the force of gravity, the flanges are horizontal and the web is vertical. An I-beam has two flanges top and bottom with a web centered between them. A C-beam (or channel) has two flanges, top and bottom, with a web connecting the ends of the flanges. A T-beam has a single flange and a web connected at the center of the flange. An L-beam (or angle) has a single flange with a web connected to the end. A BOX-beam has two flanges connected at the ends to the ends of two webs thereby forming a box-like section. There are many variations of these structures which may be used for the platform of this invention.
[0055] An example of the use of C-beams as the basis of the platform structure is the rectangular frame shown in FIG. 2 . A platform customized for the particular set of modules shown in FIG. 1 is obtained by inserting I-beam cross-members in the frame as shown in the top view of FIG. 3 .
[0056] Cross-members 25 and 27 (together with the frame) provide support for modules 13 , 15 , and 17 . Cross-members 29 , 31 , and 33 (together with the frame) provide support for the front two mobility modules 19 . Cross-members 35 and 37 (together with the frame) provide support for left rear mobility module 19 , and cross-members 39 and 41 (together with the frame) provide support for right rear mobility module 19 .
[0057] A top view of the upper left corner of the platform shown in FIG. 3 is shown in FIG. 4 . Frame 23 has holes as shown (typical frame hole 43 ) spaced at regular intervals on its entire perimeter. The holes pass through both flanges of the channel and are partially threaded at both top and bottom. The cross-members (typical cross-member 45 ) also have partially-threaded holes (typical cross-member hole 47 ), with the same regular spacing as the frame and aligned with the frame holes after the cross-member is inserted into the frame. The cross-member holes are on both sides of the web and aligned (see typical aligned cross-member holes 47 and 49 ).
[0058] The flanges of the end portions of the cross-members are removed leaving only the webs as shown for one end in FIG. 5 . Each cross-member end 51 has a hole 53 through the web which aligns with top and bottom holes 55 and 57 of frame segment 59 or similar holes of another cross-member when the cross-member is fully-inserted into the frame or other cross-member (see FIG. 5 ).
[0059] The dashed outline 19 ( FIG. 4 ) shows the outline of the left rear mobility module (see FIG. 1 ) relative to the platform.
[0060] A cross-member can be quickly attached to the frame, to the frame and another cross-member, or to two other parallel cross-members by inserting and screwing threaded pins into pre-drilled and partially threaded holes in the frame and cross-members. The attachment of one end of a cross member 61 to a frame 59 (see FIG. 5 ) proceeds by inserting the end 51 of cross-member 61 into frame 59 .
[0061] A sectional view of the frame 59 and cross-member 61 after insertion in a plane normal to the cross-member longitudinal axis is shown in FIG. 6 . A sectional view in the central plane of the cross-member web is as shown in FIG. 7 . The cross-member is secured to the frame by pin 63 which is threaded at one end with a recess in the threaded end which accepts an Allen wrench. The pin is passed through the holes in the frame and the cross-member and then secured to the frame by causing the pin threads to fully engage the threads 65 in the threaded region of the frame hole. Pin 63 does not extend into the threads 66 of bottom frame hole 57 (see FIGS. 5 and 7 ). Pin 63 may alternatively be inserted through hole 57 and secured in position by engagement with threads 66 in bottom frame hole 57 .
[0062] The attachment of a cross-member to another cross-member is accomplished in the same way.
[0063] The frame need not be constrained to two dimensions as illustrated in FIG. 2 . The frame may assume any three-dimensional configuration that can be achieved with structures of beams. The only requirement is that the beam structure accommodate module attachment points (corresponding to the mounting holes shown in the drawings) in the module mounting surfaces of the structure that are congruent with a subset of a grid of attachment points equally-spaced in the two dimensions of a two-dimensional Cartesian-coordinate system.
[0064] Nor does the frame need to be constrained to the simple rectangular shape shown in FIG. 2 . The frame may be of any geometrical shape achievable with a structure of beams as long as the attachment-point requirement is satisfied.
[0065] The transmission of power and the communication of information among modules is accomplished with buses. Bus 67 and buses 69 and 70 shown in FIG. 6 are identical arrangements of parallel conductors attached to insulating back planes which are in turn attached to the interior web surfaces of the frame and cross-members respectively. One possible bus layout is shown in FIG. 8 . It consists of AC power bus 75 , DC power bus 77 , and data bus 79 attached to bus support structure 81 . A sectional view normal to the conductors is shown in FIG. 9 .
[0066] The current required to provide the mobility desired for a mobile modular assembly may require power bus conductors having dimensions normal to current flow of a centimeter or more. Thus, the size of power bus conductors are likely to be significantly greater than the data bus conductors. In order to simplify the connections to the combination power and data bus, it is desirable that the surfaces of the conductors available for connection be in the same plane as illustrated in FIG. 9 . The design of the bus support structure 81 accomplishes this goal.
[0067] The connection of a cross-member bus to the frame bus is accomplished with cross-member connector 71 which is shown in the sectional view of FIG. 10 and which is attached to the end of cross-member 61 . Tabs 73 abut the sides of the cross-member bus conductors and are either soldered or ultrasonically welded to them. An identical connector is attached to the other end of cross-member 61 and is electrically connected to the cross-member bus conductors on the opposite side of the cross-member web.
[0068] The details of the cross-member bus connector 71 are shown in FIG. 11 . Flexible DC power connector fingers 85 , AC power connector fingers 87 , and data connector fingers 89 are held in support structure 83 , the ends of which exit the support structure 83 as DC power connector tabs 91 , AC power connector tabs 93 , and data connector tabs 95 which are soldered or ultrasonically welded to the cross-member bus conductors as described above.
[0069] In attaching a cross-member to a frame or to another cross-member, the connector fingers bend and thereby apply pressure to the corresponding bus conductors in the contact region, thereby assuring a good electrical connection between the bus conductors being connected.
[0070] The connection of the frame buses at the corners of the frame is accomplished with the corner connector shown in FIG. 12 . The corner connector consists of two sets of flexible connector fingers 97 and 99 held in a plastic support structure 101 . When installed in a corner of a frame, the connector fingers make individual contact with the bus conductors on each side of the corner as shown in FIG. 13 .
[0071] Frame buses 103 and 105 are attached adhesively to interior web surfaces 107 and 109 respectively of adjoining frame members at the corner of a frame. The corner connector 111 is initially positioned as shown and held in position by a pin which is inserted through the two corner holes of the frame and hole 113 in cam 115 . A front view of the corner connector is shown in FIG. 14 . This assembly process is easily accomplished since the connector fingers 97 and 99 are unflexed during the assembly process. Cam 115 is equipped with a square protuberances 119 and 121 at each end of the cam to which a wrench can be applied. By rotating the cam with the aid of a wrench to dashed position 123 , the connector support structure 101 moves into the corner thereby causing the connector fingers to flex and make good electrical contact with the bus conductors.
[0072] A module such as the ones shown in FIG. 1 has outside width and length dimensions equal to WS and LS respectively where W and L are integers and S is the spacing of the holes in the frame and cross-members. The module may have an arbitrary height. The top and bottom of a module have a rectangular arrangement of holes that can be aligned with those in the platform. The rectangle defined by the hole centers is centered in the module surface with (W-1) holes in the width dimension and (L-1) holes in the length dimension.
[0073] The attachment of a module 125 to a platform 127 begins with the alignment of the holes in the module with the holes in the platform where the module is to be attached as illustrated in FIG. 15 . Then a shoulder bolt, with the aid of a driving tool, is passed through top hole 129 of module 125 and is caused to enter bottom hole 131 and engage the threaded region 133 of the hole in the platform. This process is then repeated for as many aligned holes as required to provide the requisite attachment security.
[0074] In preparation for attaching a module to the top of module 125 , reducing bushing 135 is introduced into hole 129 from the top and screwed into the threaded region utilizing an Allen wrench inserted into the hexagonal socket 136 thereby converting the original threaded region into a threaded region which is the same size as the threaded hole regions in the platform. Similarly, reducing bushings are screwed into all of the top holes of module 125 which are to be used in attaching the second module.
[0075] A second module 137 is shown in FIG. 16 positioned for attachment to module 125 . It will be observed that reducing bushing 135 has been installed in the top hole of module 125 . Module 137 is bolted to module 125 in exactly the same way that module 125 was bolted to platform 127 (bolt not shown in figure).
[0076] After all of the desired modules have been mounted on the platform, plugs like plug 139 are screwed into all exposed open top holes in the modules in order to maintain dust-free environments within the modules.
[0077] Each module includes a bus and a bus connector which can be caused to connect the module's bus to the platform bus system or to the bus of a module on which the module is mounted. The installation of a bus connector in a module is accomplished (prior to attachment of the module to the platform or to another module) by aligning two tapped holes in the bus connector with two of the holes in the bottom of the module and then bolting the bus connector to the module. For example, if one wished to attach a bus connector to either module 125 utilizing hole 141 or module 137 utilizing hole 143 , neither hole being intended for use in attaching the associated module to the platform or another module, one would align the two tapped holes of the bus connector with hole 141 (or 143 ) and an adjacent hole and utilizing shoulder bolts like shoulder bolt 145 to bolt the bus connector to the module using an Allen wrench. The precise positioning of the bus connector with respect to the module is assured by the close fit of the shoulder 147 of the bolt and hole 141 (or 143 ) and similarly in the case of a second bolt and the adjacent hole.
[0078] Each module is equipped with a bus system similar to the platform bus system. A module's bus system consists of four buses adhesively attached to the walls of the module at the same distance from the top of the module as the platform buses are from the surface (either top or bottom) of the platform. Alternatively, the module buses may be attached to the walls of the module by mechanical fasteners of one kind or another. The four busses are electrically connected together by corner connectors.
[0079] After a module 171 is mounted to the platform 173 , the module bus is electrically connected to the platform bus by pivoting bus connector 185 as shown in FIG. 17 . Two of the four interconnected module bus sections 175 and 177 are shown together with junction bus 179 , junction bus termination 183 , and platform bus 180 . The module bus sections 175 and 177 are electrically connected by a corner connector which attaches to corner attachment fixture 178 . Junction bus connector 181 connects module bus section 177 to vertically-oriented junction bus 179 . Junction bus termination 183 provides an interface between junction bus 179 and pivoting bus connector 185 . Pivoting bus connector 185 provides the means for connecting junction bus termination 183 to platform bus 180 after the module has been attached to the platform. The pivoting bus connector frame 187 , which supports the pivoting bus connector 185 , is attached to a module by shoulder bolts which pass through adjacent holes in module 171 and screw into tapped hole 189 and an adjacent tapped hole which align with the two adjacent holes in the module thereby securely and precisely attaching the pivoting bus connector frame 187 to the module.
[0080] The corner bus connector which attaches to corner attachment fixture 178 and connects module bus section 175 to module bus section 177 is detailed in FIG. 18 . The view is the backside of the connector showing the surfaces of flexible connector fingers 191 and 193 that make contact with module bus sections 177 and 175 respectively. Plastic corner connector support structure 195 provides support for the molded-in phosphor bronze connector fingers 191 and 193 . Holes 197 and 199 provide the means for attaching corner connector support structure 195 to corner attachment fixture 178 ( FIG. 17 ) in a module.
[0081] The front view of corner connector support structure 195 together with portions of the protruding fingers 191 and 193 are shown in FIG. 19 . The countersunk regions 201 and 203 prevent the attaching nuts from obstructing or interfering with circuits and devices that will be installed in the module. A sectional view of corner connector support structure 195 and fingers 191 and 193 in position to be attached to corner attachment fixture 178 is shown in FIG. 20 . Corner attachment fixtures are adhesively attached to the inside walls of a module at the corners.
[0082] Bolt 205 together with a second bolt are molded in to corner attachment fixture 178 in positions to match holes 197 and 199 in the corner connector support structure 195 . As shown in FIG. 20 , the corner attachment fixture bolts have entered the holes in the corner connector support structure 195 and connector fingers 193 and 191 have made contact with the conductors of buses 175 and 177 respectively but remain unstressed. The attachment process is completed by screwing nuts on the bolts until the connector fingers are fully stressed and making good contacts with the bus conductors as indicated by the corner connector support structure 195 coming into contact with the corner attachment fixture 178 .
[0083] Sectional views of junction bus 179 and module bus section 177 are shown in FIGS. 21 and 22 respectively. The only difference in the two bus types is that the module bus section 177 has shoulders 213 and 215 which are used in attaching the junction bus connector 181 at any position along the module bus section 177 . The platform buses discussed earlier are identical in configuration to the junction bus 179 .
[0084] A view of the finger configuration of the junction bus connector 181 ( FIG. 17 ) is shown in FIG. 23 . The finger assembly is molded into the junction bus connector support structure 217 as shown in FIG. 24 . The view of FIG. 24 is the underside of junction bus connector 181 which comes in contact with module bus section 177 and junction bus 179 .
[0085] The attachment of junction bus connector 181 to module bus section 177 and junction bus 179 is shown in FIG. 25 . The attachment is accomplished at the corners of junction bus connector 181 with clamps 219 , 221 , 223 , and 225 . The clamping details are illustrated in FIG. 26 using clamp 225 as an example. As shown in the figure, junction bus connector 181 , when placed over module bus section 177 and junction bus 179 , is supported at a distance 227 above the two buses by the undeflected fingers (not shown in figure) of the junction bus connector. In this condition, the four clamps 219 , 221 , 223 , and 225 can be slipped into position as illustrated for clamp 225 in the figure. Precise alignment of the connector and the buses can be achieved by adjusting the position of the connector until each of the two clamps 223 and 225 are positioned as clamp 225 is in the figure. Note that one side of clamp 225 abuts the edge of junction bus 179 and the opposite side is in the same plane as the edge of junction bus connector 181 .
[0086] After the clamps are correctly positioned and the junction bus connector is correctly aligned with the buses, Allen screw 229 and the Allen screws associated with clamps 219 , 221 , and 223 are all screwed into the clamps forcing the junction bus connector support structure 217 to make contact with the underlying buses and causing the fingers of the junction bus connector 181 to deflect and make pressured electrical contacts with their associated bus conductors.
[0087] The junction bus connector 181 is symmetrical and thus can be used to connect the module bus 177 to the junction bus 179 from either the left or right sides as the buses are shown in FIG. 25 . By rotating junction bus connector 181 90 degrees counterclockwise in FIG. 25 , it would connect the right-hand portion of module bus 177 to junction bus 179 .
[0088] Junction bus termination 183 shown in FIG. 27 consists of rigidly-held conducting fingers 231 with which the flexible fingers of pivoting bus connector 185 connects. The fingers 231 transition into pads 233 . The finger assembly is molded into plastic support structure 235 . After the pads are connected to the ends of junction bus 179 by soldering or ultrasonic welding and before junction bus connector 181 is connected, junction bus termination 183 and the attached junction bus 179 is inserted behind the already-installed pivoting bus connector 185 . At the beginning of the insertion, the upper portion of junction bus 179 rests on top of module bus section 179 and must be tilted away from the module wall. This tilting flexibility is provided by junction bus termination 183 being attached to junction bus 179 only by junction termination pads 233 which permits junction bus 179 to tilt away from surface 237 of junction bus termination support structure 235 . After reaching its proper position, junction bus 179 drops down to the module wall in close proximity to module bus section 177 . The surface 239 of junction bus termination 183 and junction bus 179 will be held securely against the module wall by sinusoidal spring 241 shown in FIG. 28 at one edge of pivoting bus connector frame 187 and by a second spring on the other side of the frame. The springs are held trapped in the frame as illustrated in the figure for spring 241 with its ends inserted into slots 243 and 245 .
[0089] Pivoting bus connector 185 ( FIG. 17 ) is shown in greater detail in the sectional views of FIGS. 29 and 30 . Pivoting bus connector 185 is shown parked in module 171 above platform 173 in FIG. 29 . Pivoting bus connector 185 is rigidly attached to shaft 255 whose ends are supported in frame 187 in a manner which allows the shaft to freely rotate. Worm gear 257 is rigidly attached to shaft 255 and engages worm 259 . Worm 259 is rigidly attached to a worm shaft having a hexagonal socket head termination 261 (drivable by an Allen wrench) and constrained within a hole in the frame shelf by worm 259 at one end and hexagonal socket head termination 261 at the other end. The worm shaft is free to rotate and thereby drive worm gear 257 and pivoting bus connector 185 in a ninety-degree arc thereby causing pivoting bus connector 185 to arrive at the position shown in FIG. 30 , simultaneously connecting platform bus 180 to junction bus termination 183 which is hidden between the walls of pivoting bus connector frame 187 in FIGS. 29 and 30 .
[0090] The mounting of pivoting bus connector frame 187 to the module results in hexagonal socket head termination 261 being aligned with module hole 169 ( FIG. 17 ) and also with the corresponding hole in the upper surface of the module. Thus, a user can insert an extended-length Allen wrench through the aligned hole in the upper surface of the module and engage the hexagonal socket head termination 261 to turn the worm 259 , thereby either moving the pivoting bus connector 185 from the parked “disconnect” position in the module ( FIG. 29 ) to the operational “connect’ position ( FIG. 30 ) wherein platform bus 180 becomes connected to junction bus termination 183 ( FIG. 17 ) or performing the reverse operation which results in platform bus 180 becoming disconnected from junction bus termination 183 .
[0091] Socket head termination 261 may be driven with an electric motor attached to frame shelf 263 and a user may then access the motor and supply power to it by inserting an extended-length power wand through the aligned hole in the upper surface of the module and into a power receptacle attached to the electric motor.
[0092] The dashed outline of finger assembly 265 in FIGS. 29 and 30 shows the position of the finger assembly that attaches to the conductors at the end of pivoting bus connector 185 and makes the connection to the fingers of junction bus termination 183 which is hidden within the walls of pivoting bus connector frame 187 and which connects to junction bus 179 . A similar finger assembly 267 attaches to the conductors at the other end of pivoting bus connector 185 and makes the connection to the conductors of platform bus 180 .
[0093] The pivoting bus connector 185 is an assembly of conductors terminated on one end with finger assembly 267 consisting of a plurality of vertically-oriented linear array of flexible conducting fingers which are intended to make contact with the conductors of the platform bus 180 and terminated on the other end with finger assembly 265 consisting of a horizontally-oriented linear array of flexible conducting fingers which are intended to make contact with the conducting fingers of the junction bus termination 183 ( FIG. 17 ).
[0094] The pivoting-connector conductors emerge from finger assembly 267 as a vertically-oriented array shown in FIG. 31 as solid-line squares. Each conductor is subject to a series of bends about axes normal to the sides of the conductors including a ninety-degree change in direction which bring them into the square configuration of dashed squares shown in FIG. 31 . This square configuration is achieved when all of the conductors are aligned vertically in FIG. 30 . The transition from a linear configuration to a square configuration requires the conductors to be displaced by bends as indicated by the arrows in FIG. 31 .
[0095] Each conductor is then subject to a series of bends about axes normal to the sides of the conductors including a ninety-degree change in direction which brings them into the linear horizontally-oriented configuration of solid-line squares shown in FIG. 32 . The transition from the square configuration to the linear configuration requires displacements of the conductors as indicated again by the arrows.
[0096] A yoke for attaching shafts to the pivoting bus connector surrounds the conductor assembly at the pivot axis. The yoke, shown in FIG. 33 , has two tapped holes 275 and 277 on the pivot axis to receive shafts with threaded ends that pass through holes in the side walls of pivoting bus connector frame 187 ( FIG. 17 ) and screw into the tapped holes in the yoke.
[0097] Finger assemblies 265 and 267 with individually-flexible fingers for making electrical contact with the platform bus 180 and the junction bus termination 183 ( FIG. 17 ), like that shown in FIG. 34 , are attached to each end of the conductor assembly by soldering or ultrasonic welding. The resulting combination of conductor assembly, yoke, and finger assemblies are molded into plastic thereby completing the fabrication of the pivoting bus connector. The dashed outline 279 shows the plastic support structure that encompasses the conductor assembly and the attachment ends of the finger assembly at each end of the pivoting bus connector after the molding process has been completed.
[0098] The pivoting bus connector 185 connects to the platform bus by essentially a linear motion normal to the platform bus. First, the fingers 281 contact the bus conductors and then individually and elastically bend as they move closer to the bus conductors thereby applying forces to the contacting portions of the fingers and securing good electrical connections.
[0099] The pivoting bus connector 185 connects to the junction bus termination 183 by a rotating motion as shown in FIG. 35 . The frame 187 of the pivoting bus connector 185 abuts wall 283 and is bolted to floor 285 of module 171 ( FIG. 17 ). The fingers 287 of finger assembly 265 are shown in the “parked” position 287 -P that corresponds to the parked position of the pivoting bus connector 185 (see FIG. 29 ). As the pivoting bus connector 185 rotates, the fingers 287 rotate with the straight ends touching inner circle 289 and the curved ends touching outer circle 291 . The fingers remain undeflected during the ninety-degree rotation of the pivoting bus connector until they reach the “touching” position 287 -T where they touch the ends of the junction bus termination fingers 231 ( FIG. 27 ). Further rotation causes the fingers to bend elastically until they achieve the “maximum bending” position 287 -MB and good electrical connections to the junction bus termination fingers after a full ninety-degree rotation of the pivoting bus connector.
[0100] Electrical connections to electrical and electronic devices and equipments within a module are accomplished by any of a wide variety of conventional wiring means and bus connector 293 shown in FIG. 36 . Bus connector 293 is clamped to the module bus using clamps like clamp 225 shown in FIG. 26 in a fashion similar to the way junction bus connector 181 is clamped to module bus 177 (see FIG. 25 ). Bus connector 293 may be attached wherever on the module bus is most convenient for wiring, and the clamps may be placed anywhere along the two sides of the connector which are above the shoulders 213 and 215 of module bus 177 (see FIG. 22 ).
[0101] The clamping of bus connector 293 to module bus 177 results in the surfaces 295 and 297 of bus connector 293 being in intimate contact with the top surfaces of shoulders 213 and 215 ( FIG. 22 ) of module bus 177 . This positioning results in bus connector fingers 299 flexing to the degree 301 necessary to make good electrical contacts with the module bus conductors and also limits the flexing to the elastic region.
[0102] Bus connector fingers 299 are electrically connected by a rigid conductor assembly to the receptacle contacts of any type connector preferred by the user. Circular plastic connector (CPC) 303 , capable of handling up to eight signal conductors and five power conductors, is shown in FIG. 36 . A plurality of receptacles may be provided on a single bus connector 293 utilizing any or all of the five surfaces (bottom and four sides). The receptacles may be the same or different depending upon the user's preferences.
[0103] Bus connector 293 is molded into plastic and becomes the bus connector shown in FIG. 36 except for possibly having a plurality of receptacles available instead of just one.
[0104] In order for the pivoting bus connector in a module to connect to a bus beneath the module, there must be an opening in the floor of the module. For the embodiment of the invention described herein (see FIG. 4 ), the rectangular opening 321 shown in FIG. 37 would suffice. In order to maintain a dust-free environment within the module, hinged spring-loaded cover 323 covers the portion of the opening not occupied by the pivoting bus connector after the pivoting bus connector moves from the “parked” position to the “connect” position. The manner in which the cover is opened and closed is illustrated in FIG. 38 .
[0105] When the pivoting bus connector 325 is in the “park” position 325 -P, the cover 323 -O is open and leaning against the pivoting bus connector. The cover 323 is spring-loaded so that a force is continually being applied to the cover to cause it to move to the closed position unless it is prevented from doing so by the pivoting bus connector.
[0106] When the pivoting bus connector 325 moves to the “connect” position 325 -C, the cover 323 shown in the open position 323 -O follows it down to the closed position 323 -C and closes the portion of opening 321 not occupied by the pivoting bus connector. In order to maintain a dust-free environment when the pivoting bus connector 325 is in the connect position 325 -C an elastically-compressible dust seal 327 is attached to cover 323 on its perimeter and elastically deforms to seal that portion of opening 321 where the cover abuts the opening. An elastically-compressible dust seal 329 surrounds the neck of the pivoting bus connector and elastically deforms to seal that portion of opening 321 that surrounds the neck when the pivoting bus connector is in the “connect” position 325 -C. | The invention is a modular assembly of modular objects for autonomously executing a variety of tasks. The modular assembly consists of a modular object called a platform, one or more modular objects called modules which are mounted to the platform in accordance with a modular assembly system, and a modular bus system for distributing electrical power and electrical signals among the modular objects in the modular assembly. The modular assembly system utilizes modular object fasteners (MOFs) and MOF-accommodating features of modular objects for facilitating the attachment of a plurality of modular objects to one another thereby creating a modular assembly in any one of a variety of configurations, an MOF being activatable when object attachment surfaces associated with two modular objects are superimposed and two object attachment points on the object attachment surfaces coincide. |
CROSS-REFERENCE TO RELATED APPLICATION
BACKGROUND OF THE INVENTION
This invention is concerned with providing a fuze in a solid electrolyte capacitor and relates to an improvement to the methods and the capacitors described in commonly assigned U.S. Pat. No. 4,899,258 issued Feb. 6, 1990 and U.S. application Ser. No. 07/474,572 filed Feb. 2, 1990.
A solid electrolyte capacitor, especially one of the tantalum type, essentially comprises a porous anode from which projects an anode wire. The porous anode is completely or partly covered with various layers: in practice these layers are of dielectric/oxide and of manganese dioxide substantially filling the pores of the anode and constituting the solid electrolyte, and a conductive layer forming the cathode. This structure constitutes a capacitor body which is covered with an electrically insulative material after fixing the electrodes to connecting tangs which terminate in output leads. The capacitors obtained in this way are very compact with simple geometrical shapes of cylindrical or more usually rectangular parallelepiped-shape.
With the aim among other things of reducing the unfortunate consequences of a short-circuit in a circuit comprising one or more solid electrolyte capacitors attempts have been made to integrate a fuze into the capacitor with minimum increase to its overall dimensions.
Various types of capacitors with integral fuzes are already known. Examples can be found in the documents U.S. Pat. No. 4,107,762; U.S. Pat. No. 4,224,656; EP 0,232,868; and FR 2,633,770.
The documents U.S. Pat. No. 4,224,656 and EP 0,232,868 determine the effective length of the fuze wire using an additional support member apparently needed during manufacture to hold the areas to which the ends of the fuze wire must be attached a predetermined distance apart.
The object of the previously mentioned U.S. Pat. No. 4,899,258 is to simplify further the integration of a fuze into a solid electrolyte capacitor and therefore to reduce its cost, while achieving a comparable level of performance, by eliminating any intermediate support member disposed between the negative connecting tang and the other electrode. It proposes, to this end, the provision of a predetermined effective length of calibrated fuze wire between two electrically isolated sections of the tang, which is directly connected by one of its sections to the other electrode.
The various solutions described above share the disadvantage of having no easy way to check the integrity of the fuze because it is in series with the capacitor proper, as this is essential for it to fulfil its function.
The previously mentioned patent application Ser. No. 07/474,572 is directed to meeting the object of U.S. Pat. No. 4,899,258 by additionally providing an easy way to check the integrity of the fuze by providing a solid electrolyte capacitor body fitted with two electrodes respectively connected to two connection tangs constituting the (+,-) output leads, a fuzible member of predetermined length being mounted in series between the capacitor body and a selected (-) output lead, such that the connecting tang incorporating the selected output lead is formed by a first section fixed to one of the electrodes to form a test lead and a second section electrically isolated from the first section and from the capacitor body to form the selected (-) output lead, the fuzible member providing the only electrical connection between these sections and being surrounded with a rigid or flexible and thermally insulative supporting mass of resin extending between the two sections.
SUMMARY OF THE INVENTION
An object of this invention is to achieve the same advantages as previously, especially with regard to the accuracy and the reproducibility of the fuzing characteristics of the fuze, but at lower cost and with a simpler design. It is particularly directed to avoiding the use of a separate, attached fuze requiring assembly operations.
To this end, this invention proposes a solid electrolyte capacitor of the aforementioned type in which the integral fuze is in one piece with the lead frame sections electrically separated by the fuze.
In other words, this invention proposes a solid electrolyte capacitor body embedded in a block of electrically insulative resin with two electrodes respectively electrically connected to two connecting tangs which project from the block to constitute output leads (+,-), a fuzible member of predetermined useful length being disposed in series between the capacitor body and a selected output lead (-), such that the connecting tang incorporating the selected output lead is formed by a first section fixed to one electrode of the capacitor body and projecting out of the block to form a test lead and a second section projecting out of the block to form the said (-) output lead, the second section being electrically connected to the first section and to the capacitor body only by an elongated strip of the frame in one piece with these sections and constituting the fuzible member, which is embedded in a supporting mass of rigid or flexible thermally insulative resin extending between the two sections, the supporting means being embedded in the resin block.
According to preferred features:
said sections extend parallel to each other from the fuzible member which is attached to them transversely to the exterior of the resin block to link the test and output leads;
the first and second tang sections comprise two coplanar parallel lugs joined by the fuzible member;
the elongate strip forming the fuze incorporates a central area of minimal cross-section;
said sections and said narrow strip are the same thickness and the elongate strip comprises to either side of the central area wider areas whose width is greater than that of the central area, these wider areas being joined to said sections by end areas with widths between the width of the central area and the wider areas, respectively:
the end areas are the same width as the central area;
at least one flank of the elongate strip is straight:
the supporting mass is made from a resin that is not carbonized at the temperature at which the fuzible member melts:
the supporting mass is made from a resin polymerized by ultra-violet light:
the capacitor body incorporates a porous tantalum core.
This invention also provides a method for manufacturing a solid electrolyte capacitor with an integral fuzible member in which:
a capacitor body provided with electrodes is produced:
there is cut from a constant thickness plate at least one discontinuous strip connected to a reference frame and comprising, on the one hand, two generally parallel sections joined by a transverse strip forming the fuze and, on the other hand, a third section, all three sections being fixed to said frame, one of the parallel sections being longer than the other:
the sections of the discontinuous strip are bent along transverse bending lines to their final shape:
the fuzible member is surrounded with a supporting mass of thermally insulative rigid or flexible resin extending between the parallel sections:
the capacitor body and part of the connecting tangs are overmoulded with a block of electrically insulative resin: and
the tangs are separated from the reference frame to form the capacitor leads.
BRIEF DESCRIPTION OF THE DRAWINGS
Objects, characteristics and advantages of this invention emerge from the following description given by way of non-limiting example with reference to the appended drawings in which:
FIG. 1 is a cross-section of a tantalum capacitor incorporating an integral fuze of this invention:
FIG. 1A is an electrical circuit schematic of the capacitor of FIG. 1:
FIG. 2 is a partial plan view of a plate from which are stamped the connecting tangs of the capacitor of FIG. 1:
FIG. 3 is a partial perspective of the plate of FIG. 2 after being bent to shape: and
FIG. 4 is an enlarged view of detail IV of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a tantalum capacitor 1 comprising a capacitor body 2 from which projects a tantalum anode rod 3. The capacitor body 2 is of any appropriate known type with a surface oxidized tantalum porous core covered with a solid electrolyte formed of manganese dioxide and partially covered with various appropriate layers including an outside electrode layer 4 electrically isolated from the anode rod 3.
A conductive positive connecting tang 5 is fixed to the anode rod 3 (by means of a cut-out 5A) and a conductive negative connecting tang 6 is fixed to the electrode layer 4.
The entire assembly is embedded in a rectangular parallelepiped-shape block 7 of insulative material, in practice an epoxy resin of any appropriate type, so that the conductive tangs 5 and 6 project to form + and - output leads. Recesses 8 and 9 are provided adjacent opposite edges of the block 7 so that the free ends of the tangs 5 and 6 may be folded back for the most part within the profile of the block 7.
The conductive tang 6 is actually divided into two sections 6A and 6B the only electrical connection between which is an elongate (narrow) strip 10 perpendicular to the plane of FIG. 1 forming a calibrated fuze. One of these sections (6B in this example) extends as far as the capacitor body 2, but both 6A and 6B project externally of the block 7. Portion 6A defines a negative output lead A and the portion 6B defines a test lead B.
The fuze wire 10 is in one piece with the sections 6A and 6B, being formed by stamping, as will be explained later. The sections 6A and 6B incorporate respective parallel lugs 12 and 13 between which is a space of predetermined constant width (see FIG. 3) which determines the effective length of the fuze 10. The narrow strip 10 is embedded in a protective resin 14 which adheres to the lugs 12 and 13.
The essential role of the protective resin 14 is to provide thermal protection for the insulative resin of the block 7 if the fuze melts due to an excessively high current: this enables precise definition of the fuzing characteristics (around 1425° C. for a ferro-nickel fuze containing 41% nickel). Protective resin 14 is preferably one which does not carbonize at the temperature at which the fuze melts, so as to avoid introducing any residual resistance.
This thermally insulative protective resin 14 which does not carbonize at the temperature at which the fuze 10 melts is, for example, available under the trade names CHIPBONDER 360 or LID 1043 resin. It may equally well be a silicone resin, for example AMICON XS 2213/102.
Resin 14 may also be similar to the resin of the block 7, although it is formed before the latter block (see below) and so defines in the finished capacitor 1 an interface whereby its existence may be confirmed.
An orifice 15 may advantageously be provided in the tang 5 to strengthen its attachment to the block 7.
FIGS. 2 and 3 show two successive stages in the manufacture of capacitor 1, selected to show the details of forming the tangs 5 and 6A/6B and the fuze 10.
FIG. 2 shows part of a constant thickness plate of lead frame 100 of electrically conductive material (for example, FN 42 iron-nickel alloy) from which various shapes (hatched areas with widely spaced hatching lines) have been cut (for example stamped) out.
The lead frame 100 comprises two horizontal strips 20 and 21 Joined by vertical strips 22, 23, etc. and includes locating holes 24 and 25. This arrangement is reproduced identically and periodically along the horizontal strips.
Within the frame of reference constituted by the strips 20 through 23 there is formed a discontinuous vertical strip 26 providing sections with coplanar flanks adapted to become the connecting tangs 5, 6A and 6B and the fuze 10 of the capacitor 1 of FIG. 1.
Starting from the horizontal strip 20 and the same end as the strip 22, the strip 26 comprises a section 26A adapted to form the tang 6A and, at the same end as the strip 23, a section 26B adapted to form the tang 6B.
The sections 26A and 26B are separated by a slot 16 which is widened between two portions of these sections adapted to form the portions 12 and 13 seen in FIG. 3. The transverse strip 10 separates this widened end of the slot 16 from a space opening laterally towards the right between the ends of the section 26A and the widened head 26B' of the section 26B.
The strip 26 finally comprises a section 26C attached to the horizontal strip 21 and adapted to form the lug 5 of the capacitor 1, in which are formed the hole 15 and the cut-out 5A of the section 5.
A strip 27 to the left of the strip 26 likewise comprises similar sections 27A, 27B and 27C, and so on.
FIG. 4 shows the tang 10 in detail with, on the side of the slot 16, a straight flank 40 and, on the side of the section 26B, an undulating flank 41 having three troughs separated by two peaks. The tang 10 therefore comprises three areas of minimal width of which the central area 42 is to become the (accurately localized) area of the fuze which blows, while the end areas 43 and 44 which connect the fuze 10 to the strips 12 and 13 are provided to minimize diffusion towards the strips 12 and 13 of the heat released when the fuze blows.
The wider areas 45 and 46 enable the strip 10 to be gripped firmly during stamping, so as to prevent the metal flowing in the stamping die.
It is mainly the width 1 of the central area 42 which requires to be defined with great accuracy: the end areas 43 and 44 have a width which is the same as or greater than that of the central area. The areas 45 and 46 have, for example, a width 1' of around twice that 1 of the central area. In practice the undulating flank 41 has the same radius of curvature R in its troughs and peaks.
To give an example, the fuze strip has a length L of 0.8 mm with 1=0.06 mm, 1'=0.1 mm, and R=0.2 mm, and a thickness of approximately 0.1 mm.
With the materials specified above, these dimensions are such that the central portion of the fuze melts in less than 5 s with a current of 3.5 A.
In an alternative embodiment the flank 40 can also be undulating with three troughs and two peaks, the flank 41 retaining its undulating profile or being straight.
In a further alternative embodiment both flanks 40 and 41 are straight.
Other shapes are feasible for the strip 10, for example a single central area of reduced thickness, the width of the strip being substantially constant.
The manufacture of the capacitor continues by bending the stamped plate 100 along the bending lines A through E so as to impart to the sections of the strips 26 and 27 the configuration required for the tangs 5, 6A and 6B. The bending lines are shown in FIG. 3. This bending is not applied to the strips 22, 23, etc. which with the strips 20 and 21 therefore define a reference plane.
The protective resin 14 is then applied to the strip 10. For reasons of ease of use, the resin 14 is advantageously of a type which polymerizes on exposure to ultra-violet light. As previously mentioned, it is advantageously CHIPBONDER 360 or LIK 1043 resin. It may equally well be AMICON XS 2213/102 SILICON resin, etc.
A capacitor body 2 is prepared and the (usually silver-plated) edge opposite the anode rod 3 is advantageously covered with a layer 31 of any appropriate type insulative resin to prevent any possibility of short-circuiting between this edge and the vertical part of the sections 6B and 6A of the tang 6. Alternatively this insulative resin is applied directly to the vertical part of the sections 6B and 6A.
The capacitor body 2 is then offered up to the sections 5, 6A and 6B; the horizontal part of the section 6B is bonded to the body 4, in practice with adhesive 32 containing silver, and the tang 5 is welded to the tantalum wire 3.
The combination of the capacitor body and the tangs 5, 6A and 6B is then placed between the component parts of a mould, using the strips 20 through 23 as locators. The resin 7 is injected and when it has polymerized (in practice at high temperature) the capacitor is removed from the mould. This moulding operation is carried out for each strip 26, 27 etc. stamped out from the plate 100.
It then remains only to cut the areas joining the tangs 6A and 6B to the strips 20 and 21. The capacitor 1 with integral fuze 10 is then ready for use. The + and A ends of the strips 5 and 6A are the connecting leads for the capacitor with the integral fuze 10. The end B of the strip 6B is the test lead which can be used to verify the continuity of the fuze (tested between A and B).
The foregoing description has been given by way of non-limiting, illustrative example only and numerous variations thereon may be put forward without departing from the scope of the invention. For example, the fuzible strip might be provided in the positive tang; it could equally well be provided at the end of the capacitor body rather than at one side. | A solid electrolyte capacitor in a block of electrically insulative resin is provided with two electrodes connected by respective connecting tangs to output leads (+, -) and to a fuze test lead; one connecting tang (6) is formed by a first section (6B) fixed to one of the electrodes and projecting out of the resin block to form the fuze test lead, and a second section (6A) projecting out of the resin block to form a conventional terminal; an elongate strip (10) forms the fuze in one piece with the sections (6A,6B) so as to provide the only electrical connection between the sections; the fuze is coated with a supporting mass of thermally insulative resin extending between the two sections and embedded in the resin block. |
FIELD OF THE INVENTION
The invention relates to a system and method for repelling birds from landing, roosting and/or nesting on surfaces of outdoor structures or from entering into openings in outdoors structures.
BACKGROUND OF THE INVENTION
It is well known that birds often roost, build nest and/or congregate on window ledges, fences, bell towers, gutters, roof tops, air conditioner units, light poles and a variety of other outdoor structures. Such congregations of birds can be a nuisance to property owners as well as to the general public. For example, in urban settings, large numbers of pigeons tend to inhabit any structure which offers some shelter and an opening that provides a means of egress for the birds. Such open structures can become a repository for large quantities of bird droppings. Bird droppings often become unsightly, malodorous and unsanitary and, therefore, require frequent cleaning of the area of accumulation.
In the past, there have been several attempts to devise a system to solve the problem of bird nuisance landing, nesting and roosting. One example of such a system is U.S. Pat. No. 5,713,160, issued to Heron, which discloses a retractable bird deterring device. The deterring device included holding mechanisms having a base plate attached to the building and pivotally mounted arms for securing wire between the wire holding mechanisms. The arms are selectively pivotable to an operational protracted position in which the arms and wire lie above the surface of the building and to a non-operational retractable position in which the arms and wire lie below the surface of the building structure.
Another attempt to solve the problem is disclosed in U.S. Pat. No. 5,092,088 issue to Way which discloses a device for deterring birds from roosting or nesting on building ledges and the like. The device comprises opposing brackets mounted on the ledge with one or more wires linking the opposing faces of the brackets and positioned so that when the device is in its assembled position the wires obstruct the roosting or nesting activities of the bird. One of the brackets has one or more wire retracting means enclosed within it to which the wires are mounted so that the length and tension on the wires are adjusted, either separately or collectively.
The previous attempts to provide a barrier system for repelling birds have been found to suffer from a number of drawbacks. For example, those systems include a number of moving parts which render them more expensive to manufacture, install and maintain than is desirable. Further, due to their size and complexity, these system are readily visible when installed on a structure and therefore may detract from its visual aesthetics. Moreover, such prior systems are designed for use on relatively long, narrow window ledges and are thus not suitable to protect structure openings or structure surfaces of a variety of shapes and sizes. For instance, it is believed that those systems would not be suitable for protecting the following: gutters, light poles, openings in bell towers, or the surface of a structure having substantial width. Accordingly, there is a need for a bird repellant system that is inexpensive to manufacture, install, and maintain; that can be camouflaged to blend into its surroundings; and that is flexible enough to provide a barrier for structure surfaces and openings having a wide variety of shapes and sizes.
SUMMARY OF THE INVENTION
The present invention includes a novel line barrier system for repelling a bird from a desired portion of a structure which includes, a plurality of modular supports having a base for mounting to the structure, with the supports having at least one projecting member extending in a fixed position from said base; a fastener for mounting said plurality of modular supports to the structure; and, at least one line fixedly attached to said projecting member on more than one of said plurality of modular supports to provide a line barrier between the bird and the structure. The modular nature of the supports provides for simple and inexpensive manufacture, installation, and maintenance of the system of the present invention. It also provides the system of the invention with a great deal of flexibility in configuring the line barrier to protect a wide variety of shapes and sizes of structure surfaces and structure openings. Further, the simple design of the system having modular supports with fixed projections and fixedly attached lines to more than one of the modular supports helps reduce the expense of manufacture, installation and maintenance of the system.
In one embodiment of the invention, a novel modular support for securing line of a line barrier system is provided having a base which is adapted to be fixedly secured to a structure. The base has at least one projecting member extending at a fixed angle from the top surface of the base. At least one of the projecting members has at least one line receiving member for fixedly receiving at least one line of the line barrier. Preferably, the base of the modular support is adapted to be secured to the structure by the provision of an aperture through the base which is sized to receive a fastener. Optionally, the base of the modular support may be adapted to be secured to the structure by providing a planar lower surface having a surface material which will readily bond to an adhesive chosen for its ability to bond with both the surface material of the support and the surface material of the structure.
In another embodiment of the invention, a novel method of installing a line barrier system for repelling birds from a desired portion of a structure is provided. The method includes the following steps: (a) determining the orientation and number of lines required to create a line barrier sufficient to repel birds from a desired portion of a structure; (b) determining the number and location of modular supports required to support the determined orientation and number of lines; (c) securing the determined number of modular supports in the determined locations to the surface of the structure to support the determined orientation and number of lines; and (d) attaching the determined number of lines in the determined orientation to the determined number of modular supports to create a line barrier system sufficient to repel birds from a desired portion of the structure. In the system of the invention, the number of lines and their orientation is to a large extent determined by the installer based on the size and geometry of the desired portion of the structure to be protected and the size of the bird to be repelled. In this regard, the gaps between the lines of the barrier will be smaller for barriers designed to repel smaller birds, and can be larger, if the barrier is intended to repel only larger birds, such as pigeons or seagulls. Ideally, the gaps would be no smaller than the average size of the bird to be repelled, but may be larger if the undesirable bird species is effectively repelled with a line barrier having larger gaps. When relatively large sized areas or structure openings are to be protected from birds, it is likely that more complex line barriers having larger numbers of line and more complex interactions will need to be created.
In another preferred embodiment, a novel system and method of installing a line barrier to repel birds from a portion of a structure having a substantial width relative to the length of the modular base is provided. In this preferred system and method, it is determined that at least one line of the barrier should be oriented along the periphery of at least a portion of the structure to be protected from birds and that at least three modular supports spaced apart in a non-linear arrangement at locations along the periphery are necessary to support the line barrier. For purposes of this application, a non-linear arrangement means that, when at least three supports are arranged within the desired portion of the structure to be protected, a line extending between two adjacent supports will not intersect the third support. The determined number of supports are then secured in the determined locations and the determined number and orientation of the lines are secured to the support so that a line barrier is created. Optionally, it may be determined that at least one line should be oriented to intersect the portion of the structure to be protected. In which case, at least one line is secured to at least two of the modular supports positioned opposite each other across the periphery of the portion of the structure to be protected.
In another preferred embodiment of the system and method of the invention, a novel system and method of installing a line barrier to repel birds from a portion of a structure having substantial width relative to the length of the modular base is provided. It may be determined that the line barrier system should include at least three modular supports spaced apart in a non-linear arrangement with one support positioned in the interior of the portion of the structure from which birds are to be repelled. It is further determined that at least one line should be fixedly attached on one end to at least one projecting member on the support located within the interior of the portion of the structure to be protected and fixedly attached on the other end to at least one other modular support. The determined number of supports are then secured in the determined locations and the determined number and orientation of the lines are secured so that they create a line barrier. In some cases, it will be determined that a plurality of lines oriented to intersect the desired portion of the structure to be protected are required and additional lines running between additional supports either within the interior of the portion of the structure to be protected or positioned opposite each other across the portion of the structure to be protected may be provided. Optionally, it may be determined that at least one line should be oriented along the periphery of the portion of the structure to be protected and be secured to at least two modular supports positioned along the periphery of the portion of the structure to be protected.
In another preferred embodiment of the system of the invention, the projecting member of the modular support is a pair of posts extending substantially perpendicularly from the base of the support and having at least one ring extending from said projecting member for fixedly attaching said at least one line. The ring is adapted to secure the line preferably by tying around the ring and may optionally be secured with a bit of adhesive. The base of the modular support preferably has at least one aperture adapted to receive at least one fastener.
In another embodiment of the invention, a kit is provided which preferably includes a plurality of modular supports for securing a line barrier, a plurality of fasteners, and at least one line which may be cut to the desired length(s). The kit may optionally include an adhesive for use in securing the modular supports to a structure as an alternative to use of a fastener. The kit may also optionally include an adhesive which assists in binding the line after it is tied to one of the support means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a modular support in accordance with the present invention showing the modular support and screw for mounting the support to the ledge of a window;
FIG. 2 is an plan view of a line barrier system in accordance with the present invention mounted to a window ledge being substantially wider than the length of the modular supports; FIG. 3 is a side view taken along lines 3 — 3 of FIG. 2 showing a line barrier system secured to modular supports;
FIG. 4 is an plan view of a line barrier system in accordance with the present invention mounted to a narrow window ledge having a width substantially equal to the length of the modular supports; FIG. 5 is a side view of a line barrier system in accordance with the invention covering an opening in a structure;
FIG. 6 is a partial plan view of a line barrier system of the present invention mounted to a gutter;
FIG. 7 is a side sectional view taken along lines 7 - 7 of FIG. 6 showing the modular supports of the line barrier system mounted to the mounting straps of the gutter; and
FIG. 8 is a plan view of a line barrier system installed on the top of rectangular air conditioning unit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A modular support 20 for creating a line barrier system 22 of one preferred embodiment of the invention is shown in FIG. 1 mounted to a window ledge 24 . As can be seen in FIGS. 2, 5 , 6 and 8 , a line barrier system of the invention 22 may be created by securing at least one line 25 to a plurality of modular supports 20 . Line 25 is preferably a translucent, relatively thin monofilament line of the type used for light sport fishing, but heavier lines and lines made from other materials may be used. The use of modular supports in the system of the invention provides a great deal of flexibility in configuring the line barrier systems of the invention to the size and shape of the portion of a structure to be protected from bird landing, nesting and roosting or from entry into the interior of a structure.
As shown in FIG. 1, the modular support 20 has a base 26 which may be mounted to the window ledge 24 preferably by a screw 28 through aperture 30 which is sized to accept the screw 28 . Optionally, a variety of fasteners other than a screw may be used such as, nails, staples, rivets, or an adhesive chosen to bind to both the surface of a structure and the modular support 20 . The base 26 of the modular support 20 is preferably substantially planar having a front surface 32 and back surface 34 . In the preferred embodiment shown in FIG. 1, a pair of projecting members 36 extend from the front surface 32 of the base 26 of the modular support 20 . A ring 38 extends from each projecting members 36 to which one or more lines of the line barrier system may be attached. In this preferred embodiment, the differing length of the projecting members assures that the pair of rings 38 are maintained at different heights above the structure so that the lines attached thereto are maintained at more than one level. It is contemplated that a single projecting member and ring or additional projecting members and rings could extend from the base of the modular support, if desired. Further, while the ring structure 38 for attaching the lines is preferred, it is contemplated that other structures could be provided on the projecting member 36 for attaching lines, such as a T-bar, L-bar, knob structure or other ring structures extending from the projecting member (not shown).
As can be seen in FIG. 3, the projecting members 36 and rings 38 are relatively short, having a preferred total height of less than 3 inches. The modular supports, therefore, provide the line barrier system of the invention with a low profile when seen from the side. This low profile helps insure that the line barrier system of the invention is relatively unobtrusive when viewed from the side or from below. The low profile of the line barrier system is also a significant safety feature since it allows a human to step on top of the line barrier in the event of a fire or other emergency where one must exit through a window and onto a window ledge or other protected structure. With prior line barrier systems having significantly higher profiles, a human occupant may find it difficult or impossible to step on or over such barriers.
The modular support 20 is preferably a unitary structure fashioned from a suitable resin by injection molding. The plastic resin used to form the modular supports 20 may be tinted in a wide variety of colors to match the color of the ledge or other portion of a structure to which it is attached. If desired, the line barrier system of the invention may be constructed with translucent monofilament lines along with a color matched or translucent modular supports to provide a line barrier system with enhanced camouflage properties. In any event, the small size, simple design and low profile of the modular unit help to hide from view the line barrier system of the present invention.
Referring now to FIG. 2, a line barrier of the present invention 22 a is provided by attaching four lines 25 ac , 25 bd , 25 ad and 25 bc respectively, to four modular supports 20 a , 20 b , 20 c , and 20 d to protect the surface of a window ledge 24 a . The window ledge has a width which is substantially wider than the length of the modular supports 20 a - 20 d yet can be efficiently protected from birds using a small number of modular supports and lines. The four lines 25 ac , 25 bd , 25 ad and 25 bc are preferably fixedly attached to each of eight rings 38 a 1 - 38 d 2 of the four modular supports 20 a - 20 d . To efficiently cover the desired portion of the ledge 24 a from which birds are to be repelled, two pairs of modular supports 20 a , 20 b and 20 c , 20 d are mounted at each end of the ledge at the peripheral ledge corners. Lines 25 a and 25 b run along the periphery of the ledge 24 a and are attached to the rings 38 a 1 - 38 d 2 of the modular supports located the ledge 24 on the opposite end of the ledge 24 , that is, line 25 ac is attached to rings 38 a 1 and 38 c 1 of modular supports 20 a , 20 c and line 25 bd is attached to rings 38 b 2 and 38 d 2 of modular supports 20 b , 20 d . Lines 25 ad and 25 bc intersect the interior of the area bounded by the periphery of the ledge 24 a and terminate at modular supports 20 a - 20 d located across the ledge 24 a . Line 25 ad is attached to modular supports 20 a and 20 d at rings 38 a 2 and 38 d 1 , respectively, and crosses line 25 bc near the center point of the ledge 24 ; line 25 bc is attached to modular supports 20 b and 20 c at rings 38 b 1 and 38 c 2 . While lines 25 ad and 25 bc are shown in their preferred crossing arrangement for efficient coverage of ledge 24 a , it is contemplated that such interior lines to can be configured to run parallel to one another, that is, a line from 38 a 2 to 380 c 2 and a line from 38 b 1 to 38 d 1 (not shown), if desired.
The four lines 25 ac , 25 bd , 25 ad and 25 bc are preferably fixedly attached to each of the eight rings 38 a 1 through 38 d 2 by first tying and then applying a small amount of adhesive to the knot to prevent the knot from slipping on the monofilament line. It also contemplated that lines may be fixedly attached at one end and then looped through or around one or more rings prior to being fixedly attached at its other end. For example, rather than fixedly attaching each end of the four lines as shown in FIG. 2, a similar line barrier could be constructed by the use of a single line with one end fixedly attached at ring 38 a 1 and the second end looped through or around rings 38 c 1 , 380 c 2 , 38 b 1 , 38 b 2 , 38 d 2 , and 38 d 1 , respectively, with the second end fixedly attached at 38 a 2 . In the line barrier systems of the present invention, fixed attachment of a line to more than two supports is preferred if looping the line through rings or wrapping the line around rings is contemplated since such looping or wrapping of the line through a number of rings could lead to failure of a significant amount of line of the line barrier should one of the looped or wrapped segments break during use.
In the embodiment of the invention shown in FIG. 4, the ledge 24 b has a width substantially equal to the length of the modular supports 20 e and 20 f . Accordingly, to accommodate such a narrow ledge, as few as two supports and two fixedly attached lines may be used to provide a line barrier system 22 b of the invention. Modular supports 20 e and 20 f are preferably located at opposite ends of the ledge and are oriented lengthwise across the width of the ledge 20 b . Line 25 ef 1 is run along one peripheral sided of the ledge 24 b and fixedly attached to rings 38 e 1 to 38 f 1 , and line 25 ef 2 is run along the other peripheral side of the ledge 24 b and fixedly attached to rings 38 e 2 to 38 f 2 . In the line barrier system of the present invention, it is contemplated that substantially longer structures than the ledges shown in FIGS. 2 and 4 may require additional modular supports spaced intermediate to end supports along the length of a line to prevent the line from sagging over long distances. It is believed that the preferred distance to space apart such intermediate supports is about every 3 feet, although greater distances for spacing may be used.
In the embodiment of the invention shown in FIG. 5, an opening 40 in a structure (not shown) is covered by a line barrier system 22 c of the present invention. The line barrier 22 c is intended to prevent birds from entering the opening 40 in the structure or from roosting, landing, or nesting on the bottom ledge 42 of the opening 40 . The modular nature of the supports 20 allows for a great deal of flexibility in design of line barrier system to protect such an opening. In FIG. 5, ten modular supports 20 g - 20 p are shown in the preferred position mounted to the surface 39 defining the interior of the opening 40 . It is contemplated that the supports may also be mounted on the exterior surface 41 of the structure adjacent to the opening 40 , if desired. It is further contemplated that greater or fewer numbers of supports and lines may be required to provide an effective barrier to a structure opening depending upon the size and shape of the opening and the size of the bird species to be repelled. For line barrier systems designed for certain openings such as shown in FIG. 5, it may be desirable to use modular supports with a single projecting member and single ring.
As shown in FIG. 5, each of the nine lines 25 gp - 25 mp of the line barrier are attached on one end to one of the nine modular supports 20 g - 20 m and on the other end to the centrally located modular support 25 p mounted to the bottom ledge 42 . Line 25 gp is attached to modular support 25 g and 25 p ; line 25 hp is attached to modular support 25 h and 25 p ; line 25 ip is attached to modular support 25 i and 25 p ; line 25 jp is attached to modular support 25 j and 25 p ; line 25 kp is attached to modular support 25 k and 25 p ; line 25 lp is attached to modular support 25 l and 25 p ; and line 25 mp is attached to modular support 25 m and 25 p . It is also contemplated that lines could be attached to modular supports located on opposite sides of the opening rather than attaching one end of each of the lines to a centrally mounted support 25 p . For example, a line barrier could also be created to protect the opening depicted in FIG. 5 by attaching lines to the following pairs of modular supports: 20 g and 20 o , 20 h and 20 n , 20 i and 20 m , 20 j and 20 l , as well as 20 k and 20 p (not shown).
In the embodiment of the invention shown in FIG. 6, a gutter 44 protected by a line barrier system 22 d is shown in a partial view. The gutter and barrier extending beyond the portion shown as indicated. The modular supports 20 q - 20 s are mounted to the strap mounts 46 a - 46 c which mount the gutter 44 to a building (not shown). Line 25 q is spaced above the gutter 44 along its front wall and is fixedly attached to rings 38 q 1 and looped through lines 38 r 1 and 38 s 1 and fixedly attached to at least one other modular support along the length of the gutter (not shown). Line 25 r is spaced above the gutter 44 along its back wall and is fixedly attached to ring 38 q 2 and looped through 38 r 2 and 38 s 2 and fixedly attached to at least one other modular support along the length of the gutter (not shown). For the relatively short spans between modular supports as shown in FIG. 6, it is preferred that the lines be looped through or around at least some of the intermediately spaced supports, as for example 38 r 1 , 38 s 1 , 38 r 2 and 38 s 2 and intermittently fixedly attached to at least some of the intermediate supports along the length of the gutter. The small size and light weight of the modular supports 20 q - 20 s make it possible to mount a line barrier system of the invention to a relatively flimsy gutter made or aluminum or other relatively thin light weight metal. The gutter 44 shown in FIG. 6 is relatively narrow having a width which is substantially the same as the length of modular supports 20 q - 20 s . As a result, only a single modular supports per mount strap 46 is required to provide an effective line barrier to the gutter 44 . It is contemplated that the line barrier system of the invention could be used with wider gutters that may require more than one modular support per support strap of the gutter and more than two fixedly attached lines to form an effective line barrier.
In the embodiment of the invention shown in FIG. 8, a line barrier system 22 d of the present invention is shown mounted to the top of a rectangular air conditioning unit 48 . Six modular supports 20 t - 20 z are mounted preferably by sheet metal screws (not shown) and optionally by using adhesive on the top of the air conditioning unit 48 . Four modular supports 20 t - 20 w are mounted at an angle on the four outside corners of the air conditioning unit 48 , and two modular supports 20 x and 20 y are mounted at the center of the air conditioning unit 48 . The modular supports 20 x and 20 y are preferably mounted with the same sheet metal screw and angled relative to one another. Four lines 25 tu , 25 tv , 25 tw and 25 vw are attached to the outer pairs of rings of the corner-mounted modular supports 20 t - 20 w , that is, lines are mounted to ring pairs 38 t 1 , 38 u 1 ; 38 t 1 , 38 v 1 ; 38 v 1 , 38 w 1 ; and 38 v 1 , 38 w 1 . Four lines 25 tx , 25 uy , 25 wx and 25 vy are attached to the inner rings of the corner-mounted modular support 20 t - 20 w and the rings of the center-mounted modular supports 20 x - 20 y , that is lines attached to ring pairs 25 t 2 , 25 x 1 ; 25 v 2 , 25 y 2 ; 25 w 2 , 25 x 2 ; and 25 v 2 , 25 y 1 . Preferably, as shown in FIG. 8, each of the lines is fixedly attached to rings 38 t 1 - 38 y 2 . Optionally, one or more of the lines may be looped through or around one or more rings, if desired, to ease installation of the line barrier. It is contemplated that additional lines and support might be added to the line barrier of FIG. 8 if it was desired to repel relatively small birds from the top of the air conditioning unit 48 . For example, four additional supports (not shown) could be mounted midway between each of the corner-mounted modular supports along the periphery of the air conditioning unit and a pair of lines could be run between each oppositely mounted pair of four additional modular supports. Such additional line could be looped around or through the rings of the center mounted supports for additional support to prevent line sagging.
It is contemplated that the line barrier system of the invention may be used on a wide variety of structures such as, light poles, gutters, window ledges, fences, bell towers, roof tops, or air conditioner units. It is further contemplated that the portion of the structure to be protected from birds may be all or part of a surface of the structure or may be an opening in a structure, as for example, the opening in a bell tower.
While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention. | The present invention is directed to a line barrier system and method of installing such a system which includes, a plurality of modular supports having a base for mounting to the structure, with the supports having at least one projecting member extending in a fixed position from said base; a fastener for mounting said plurality of modular supports to the structure; and, at least one generally translucent line fixedly attached to said projecting member on more than one of said plurality of modular supports to provide a line barrier between the bird and the structure. |
STATEMENT REGARDING FEDERAL RIGHTS
[0001] This invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy. The government has certain rights in the invention.
FIELD OF THE INVENTION
[0002] The present invention relates generally to preparation of a DNA-containing-extract from an environmental sample for use with molecular biological applications such as amplification of the DNA by PCR, cloning of the DNA, enzymatic digestion of the DNA, and hybridization of the DNA with oligonucleotide probes.
BACKGROUND OF THE INVENTION
[0003] Efficient methods for extracting and purifying DNA are required for analyzing the biological composition (types of microorganisms, plant and animal cells) of environmental samples. Such analyses of environmental samples are performed for forensic investigations, for public health monitoring of pathogens in food and water supplies, for biological warfare agent detection, etc. A general procedure typically involves initial extraction of the DNA from cells and microorganisms in a soil, aqueous, or aerosol sample from the environment. This initial extraction may require steps such as incubation with detergent, freeze thawing, homogenization in a bead mill, and other steps. Subsequently, the DNA is analyzed or manipulated using one or more molecular biology techniques. One of the most common techniques applied to extracted DNA is amplification of particular DNA sequences by PCR (polymerase chain reaction), which uses extracted DNA molecules as templates from which exact DNA copies are made.
[0004] Environmental samples often contain materials that coextract with DNA and interfere in downstream molecular biology applications such as PCR. Known contaminants include metal ions, salts, complex polysaccharides, and protein-degrading enzymes. Contaminants that coextract with DNA from soil are poorly characterized and in most cases are unknown. Humic acids are known contaminants in soil that interfere with DNA quantitation (see, for example, Cheryl R. Kuske et al. in “Small-Scale DNA Sample Preparation Method for Field PCR Detection of Microbial Cells and Spores in Soil,” Applied and Environmental Microbiology, vol. 64, no. 7, pp. 2463-2472, July 1998; U.S. Pat. No. 6,350,578 to Peter C. Stark et al. entitled “Method of Quantitating dsDNA,” which issued on Feb. 26, 2002) inhibit PCR amplification (see, for example, Yu-Li Tsai et al. in “Detection of Low Numbers of Bacterial Cells is Soils and Sediments by Polymerase Chain Reaction,” Applied and Environmental Microbiology, vol. 58, no. 2, pp. 754-757, February 2002; Yu-Li Tsai et al. in “Rapid Method for Separation of Bacterial DNA from Humic Substances in Sediments for Polymerase Chain Reaction,” Applied and Environmental Microbiology, vol. 58, No. 7, pp. 2292-2295, July 1992; and Carol A. Kreader in “Relief of Amplification Inhibition in PCR With Bovine Serum Albumin or T4 Gene 32 Protein,” Applied and Environmental Microbiology, vol. 62, no. 3, pp. 1102-1106, March 1996) and interfere with other molecular biology applications (see, for example, Barbara J. MacGregor et al. in “Distribution and Abundance of Gram-Positive Bacteria in the Environment: Development of a Group-Specific Probe,” Journal of Microbiological Methods, vol. 44, pp. 193-203, 2001) even when present in very small concentrations.
[0005] A simple method for removing, from DNA extracts, contaminants that interfere with DNA quantitation and inhibit downstream applications such as PCR amplification is highly desirable.
[0006] Therefore, an object of the present invention is to provide a method for removing contaminants from soil samples, aqueous environmental samples, and environmental aerosol samples to obtain a purified extract for downstream applications such as PCR.
[0007] Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
SUMMARY OF THE INVENTION
[0008] To achieve the foregoing and other objects, and in accordance with the purposes of the present invention as embodied and broadly described herein, the invention includes a method for preparing a purified DNA-containing extract from a sample of soil, water, or particle-containing aerosol taken from the environment. According to the invention a buffered, aqueous DNA-containing extract is prepared at ambient temperature from a cell-containing sample of soil, water, or particle-containing aerosol from the environment; this DNA-containing extract includes materials that interfere with PCR amplification. N-phenacylthiazolium bromide (PTB) is added to the extract, after which a soluble portion and an insoluble portion are formed, the insoluble portion including materials that interfere with PCR amplification. After removing the insoluble portion from the soluble portion, the remaining soluble portion is a purified DNA-containing extract that can be used for PCR amplification and DNA quantitation.
[0009] The invention also includes a method for preparing a purified DNA-containing extract from a sample of soil, water, or aerosol from the environment. According to the invention, a buffered phosphate-containing solution is added to a cell-containing sample of soil, water, or aerosol taken from the environment. Cells from the sample are lysed to release DNA contained therein into the buffer. Insoluble materials are separated, and N-phenacylthiazolium bromide (PTB) is added to the soluble DNA-containing portion, forming a precipitate that is separated by centrifugation, leaving a purified, DNA containing extract that can be used for PCR amplification and DNA quantitation.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The present invention includes a method for preparing a DNA-containing extract from a soil sample, a liquid sample, or an aerosol sample for PCR amplification of the extracted DNA. The method involves adding N-phenacylthiazolium bromide (PTB) to cause selective, instantaneous precipitation of materials (presumably humic acids) that interfere with DNA quantitation and inhibit PCR amplification.
[0011] PTB been reported to increase the quantity of DNA recovered from sloth dung (see Hendrik N. Poinar, Michael Hofreiter, W. Geoffrey Spaulding, Paul S. Martin, B. Artur Stankiewicz, Helen Brand, Richard P. Evershed, Goran Possnert, and Svante Paabo in “Molecular Coproscopy: Dung and Diet of the Extinct Ground Sloth Nothrotheriops shastensis,” Science, vol. 281, pp. 402-406, 1998, incorporated by reference herein). According to Poinar et al, a buffered DNA-containing extract of sloth dung is incubated with PTB for 48 hours to promote the slow reaction between PTB and proteins that are cross-linked with DNA present in the dung (see S. Vasan, X. Zhang, A. Karpurniotu, J. Bernhagen, S. Teichberg, J. Basgen, D. Wagle, D. Shih, I. Terlecky, R. Bucala, A. Cerami, J. Egan, and P. Ulrich in “An Agent Cleaving Glucose-Derived Protein Crosslinks in vitro and in vivo,” Nature, vol. 382, pp. 275-277, 1996, incorporated by reference herein).
[0012] For processing soil according to the present invention, PTB is added to a soil extract, which causes the immediate precipitation of contaminants from the extract. In contrast to Poinar et al., a 48-hour incubation period is not required. Instead, PTB is added to the extract, which is then shaken for less than 5 minutes (or vortexed for a few seconds) and immediately centrifuged (30 seconds is usually sufficient) to separate the precipitate. The DNA in the supernatant in some cases can be diluted 10-fold and amplified by PCR directly. Alternatively, the DNA in the supernatant can be cleaned further by precipitation of the DNA (with sodium acetate and isopropanol, for example) followed by washing of the DNA trapped on a size selective filter.
[0013] The invention is an excellent purification method and is significantly better than existing methods. DNA from environmental samples such as soil samples is usually purified using spin columns containing SEPHADEX™ resin, or by selective binding to and subsequent elution from glass beads or DNA-binding membranes. Purification with a SEPHADEX™ column requires column preparation time, centrifugation of the column to remove excess buffer, and a second centrifugation step for passing DNA through the column. Soils with high humic acid concentrations may require passage through several columns before the DNA is purified sufficiently for PCR and typically the DNA must be crudely quantified and diluted prior to purification to avoid overloading a column. Purification of DNA using glass bead binding, or binding to silica membranes, typically results in loss of at least 20% of the starting DNA quantity (e.g. FastDNA™, Spin kit-Bio 101, Vista, Calif.; Mo Bio soil DNA isolation kit—Mo Bio, Solana Beach Calif.), is not very effective for purifying dilute solutions of DNA. Furthermore, these methods are much more time consuming than the method of the present invention, and are also more expensive in terms of labor and materials. Use of PTB according to the invention can, in most cases, replace existing purification methods or can be used in conjunction with existing methods. According to the invention, PTB can be used to purify DNA from a variety of environmental samples, including soil samples, aqueous samples, and aerosols. The following EXAMPLES of the invention describe details for preparing purified extracts from a soil sample (EXAMPLE 1), from a liquid sample such as river water (EXAMPLES 2 AND 3), and from an environmental aerosol sample (EXAMPLE 4). All EXAMPLES were performed at ambient temperature, which for the purposes of the invention is from about 60 degrees Fahrenheit to about 80 degrees Fahrenheit.
EXAMPLE 1
[0014] Preparation of a DNA extract from a soil sample. Soil (0.5 g) is added to a 2 ml tube containing buffer (100 mM phosphate buffer pH 7.2 with 0.0 1 % Tween 80 (a non-ionic detergent) and zirconium-silica beads (0.1 to 1 mm in diameter). The tube is shaken for 1.5 minutes on a commercially available shaker and then centrifuged for 1 minute to pellet heavy particles. The supernatant containing DNA and other soluble compounds is transferred to a sterile 1.5 ml tube, and 1M PTB was added at a 1:10 ratio (10 μl of 1M PTB per 100 μl supernatant). The PTB-containing extract was mixed by vortexing for 3 seconds and immediately centrifuged for 20 seconds to pellet precipitated material. The DNA was precipitated with 0.1 volumes of sodium acetate and 0.6 volumes of isopropanol, washed with ice-cold 70% ethanol, and resuspended in buffer (5 mM Tris[hydroxymethyl]ammoniumethane pH 8).
EXAMPLE 2
[0015] Preparation of a DNA extract from a liquid sample. A liquid sample (eg. 1 ml of river water) is added to a 2 ml tube containing buffer (e.g. 10 mM Tris[hydroxymethyl]ammoniumethane, pH 8, 1 mM EDTA, with or without detergent) and zirconium-silica beads (0.1 to 1 mm in diameter). The tube is shaken for 1.5 minutes on a commercially available instrument, then centrifuged for 30 seconds to pellet heavy particles. The supernatant (containing DNA and other soluble compounds) in the tube is transferred to a sterile 1.5 ml tube, and PTB is added as described in EXAMPLE 1 (this provides a concentration of PTB is about 100 mM). The DNA is concentrated by precipitation with 0.1 volumes of sodium acetate and 0.6 volumes of isopropanol, washed with 10 mM Tris[hydroxymethyl]ammoniumethane pH 8 in a size selection filter (eg. Microcon YM 100), and resuspended in buffer (10 mM Tris[hydroxymethyl]ammoniumethane pH 8).
EXAMPLE 3
[0016] Preparation of a DNA extract from a liquid sample. A liquid sample (eg. 100 ml of tap water from a public water utility concentrated by filtration to 1 ml) is added to a 2 ml tube containing buffer (e.g. 10 mM Tris[hydroxymethyl]ammoniumethane, pH 8, 1 mM EDTA, with or without detergent) and zirconium-silica beads (0.1 to 1 mm in diameter). The tube is shaken for 1.5 minutes on a commercially available instrument, then centrifuged for 10 seconds to pellet heavy particles. The supernatant (containing DNA and other soluble compounds) in the tube is transferred to a sterile 1.5 ml tube, and PTB is added as described in EXAMPLE 1 (this provides a concentration of PTB is about 100 mM). The DNA is concentrated by precipitation with 0.1 volumes of sodium acetate and 0.6 volumes of isopropanol, washed with 10 mM Tris[hydroxymethyl]ammoniumethane pH 8 in a size selection filter (eg. Microcon YM 100), and resuspended in buffer (10 mM Tris[hydroxymethyl]ammoniumethane pH 8).
EXAMPLE 4
[0017] Preparation of a DNA extract from an aerosol sample. An aerosol filter (a PM2.5, 47 mm Teflon filter from Washington, D.C.) is placed in a 50 ml tube containing 30 ml of buffer (100 mM phosphate buffer pH 7.2 with 0.01% Tween 80) and shaken for 15 minutes to remove particulate matter (including microbial cells) from the filter surface. The tube is centrifuged for 5 minutes at 4000 rcf to pellet the particulate matter. Excess liquid (about 29.5 ml) is removed. The particulate matter is resuspended in 1 ml of buffer, transferred to a sterile 2 ml screw-cap tube containing zirconium-silica beads (0.1 to 1 mm in diameter). The tube is shaken for 1.5 minutes on a commercially available instrument, then centrifuged for 10 seconds to pellet heavy particles. The supernatant is transferred to a sterile 1.5 ml tube, and PTB is added as described in the invention disclosure. The DNA is concentrated by precipitation with {fraction (1/10)} volume of sodium acetate, 0.6 volumes of isopropanol, and linear polyacrylamide (Gen-Elute LPA, Sigma Chemical Co.). The DNA is washed with ice-cold 70% ethanol and resuspended in buffer (10 mM Tris[hydroxymethyl]ammoniumethane pH 8).
[0018] The invention has been used to remove interfering/inhibitory materials from a wide range of soil and aerosol samples obtained from across the country. Soil samples were obtained from New Mexico, Colorado, North Carolina, California, New York, Norway, Wisconsin, Ohio, and Minnesota. PM2.5 aerosol samples from the EPA ambient air quality monitoring program were obtained from state air monitoring agencies in Miami, Florida; Nashville, Tennessee; Washington D.C.; New York, New York; Chicago, Illinois; Denver, Colorado; Phoenix, Arizona; Houston and Dallas, Texas; San Diego, San Francisco, and Los Angeles, California; and Seattle, Washington. The samples varied dramatically in total abundance of biological material (ranging, for example, from a few microbial cells to a trillion cells), abundance of humic acids, pH, amount of clay present, and mineral content.
[0019] In summary, the invention provides a more rapid, more efficient, and less expensive method for preparing DNA-containing extracts that are ready for PCR amplification than existing methods. Whereas other methods require many hours and sometimes days, the method of the invention may provide a DNA-containing extract ready for PCR amplification within 1 hour and in many cases within 5 to 10 minutes.
[0020] The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best 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. | Environmental samples typically include impurities that interfere with PCR amplification and DNA quantitation. Samples of soil, river water, and aerosol were taken from the environment and added to an aqueous buffer (with or without detergent). Cells from the sample are lysed, releasing their DNA into the buffer. After removing insoluble cell components, the remaining soluble DNA-containing extract is treated with N-phenacylthiazolium bromide, which causes rapid precipitation of impurities. Centrifugation provides a supernatant that can be used or diluted for PCR amplification of DNA, or further purified. The method may provide a DNA-containing extract sufficiently pure for PCR amplification within 5-10 minutes. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to floor maintenance equipment and, more particularly, to a floor screening attachment and a dust collection system for a floor finishing machine.
[0003] As a result of traffic induced wear, wood floors must be periodically refinished. Before the new finish is applied, the existing finish is sanded lightly or screened to promote adhesion of the new and old finishes. Screening is typically performed with a rotary floor machine of the type used for buffing, scrubbing, polishing, and a number of other floor maintenance operations. Referring to FIG. 1, typically, a floor machine 10 comprises a chassis 12 with an attached operator control handle 14 . To facilitate moving the machine 10 , a pair of wheels 16 is attached to the chassis 12 supporting the floor machine 10 when it is tipped in the direction of the handle 14 . A large diameter circular pad driver 18 , located under the chassis 12 , is connected to and rotated by a drive shaft 24 that is powered by a motor 20 and gear train 22 mounted in the chassis 12 . The pad 26 that performs the polishing, buffing, or other floor care operation is trapped between the pad driver and the floor. Friction between the pad driver 26 and the pad causes the pad to rotate with the pad driver 18 . For floor screening, the “pad” or screen 26 comprises an abrasive coated open mesh cloth having the appearance of window screen. Typically, the pad driver 18 used with a screen 26 is faced with felt to provide a resilient backing for the screen 26 . Slippage between the felt face of the pad driver 18 and the screen 26 erodes the abrasive coating of the screen 26 . The life of the abrasive on the side of the screen in contact with the pad driver 18 may be reduced by up to 50%. Since both sides of the screen 26 may be used to abrade the floor, slippage between the screen and pad driver results in a substantial increase in the cost of abrasives required to perform a screening operation.
[0004] A second problem inherent in floor screening is the production of a large quantity of fine sanding dust. The dust can be controlled and collected with a wet screening process where water is spread on the floor prior to screening. The dust produced by screening mixes with the water to form a slurry that is removed from the floor by mopping. However, the slurry is difficult clean and its presence on the floor surface obscures the surface making it difficult to judge the progress and quality of the screening operation. For these reasons, floors may be screened while dry. However, the dry screening dust easily becomes airborne and must be cleaned from any horizontal or inclined surface in the vicinity of the screening project. Further, the fine airborne finish particles produced by screening may present a health hazard.
[0005] To reduce the airborne dust produced by screening, specialized floor machines with dust collection systems have been devised. Typically, the dust collection system comprises an industrial vacuum cleaner connected to a shroud enclosing the top and the perimeter of the pad driver of the special machine. A special floor machine with a dust collection system may be justifiable for floor refinishing contractors, but many facilities have floor machines that are not equipped for dust collection and a special machine is not justifiable for periodic floor refinishing projects. Further, the quantity and fine nature of the dust produced by screening limits the effectiveness of the typical dust collection system. First, the felt pad driver used for screening comprises random fibers and has limited porosity. Air passages in the felt will quickly plug when air laden with screening dust is drawn through the felt. Since air cannot be drawn through the pad driver without frequent cleaning, the dust becomes trapped in the mesh of the screen and dust collection is only effective when the dust leaks from the edges of the screen disk. In addition, industrial vacuum cleaners rely on a dry filter element that traps particles on the surface of the element when air is drawn through pores of the filter medium. The fine dust produced by screening rapidly plugs the pores of the filter medium and the filter element must be frequently changed or cleaned if the vacuum cleaner is to continue to function.
[0006] James et al., U.S. Pat. No. 5,922,093, disclose an ultra-filtration vacuum system that includes multiple liquid and dry filtering stages. Contaminated air drawn into the cannister of the vacuum is directed into a cyclonic air stream that separates large particles and debris from the air. The separated material collects in a first liquid filter medium in the bottom of the cannister. After cyclonic cleaning, the air passes through a labyrinth filter and is injected below the surface a second liquid filter medium. The air forms bubbles that rise to the surface of the liquid where many of the bubbles collapse. The air and liquid are then dispersed in a dispersion chamber. Particles entrained in the air are wetted by the liquid and a combination of cyclonic action and baffles in the dispersion chamber separate the mixture of liquid and wetted particles which flows back into the second liquid filter medium. Particulates remaining entrained in the air are filtered by a final dry filter element. While the vacuum system throughly filters the air, it is complex and not well suited to handling large quantities of fine dust produced by floor screening. Cyclonic cleaning relies on centrifugal force to separate heavy particles and debris from the air stream but is of limited usefulness for removing the fine, light weight particles produced by floor screening. When used for floor screening, the intermediate labyrinth filter would be exposed to essentially unfiltered air and subject to rapid plugging by the screening dust. Injecting contaminated air into a liquid filter media is an effective method of filtering out fine particles, but the volume of liquid in the second liquid filter stage is limited by the necessary equipment and the presence of the first stage filter in the cannister and would rapidly reach its capacity of particulate matter when exposed to the volume of dust produced by screening.
[0007] If the finish is severely worn, floor screening may not be sufficient to prepare the floor for refinishing. In this case, as with newly installed floors, sanding the wood of the floor may be necessary to prepare the surface for the application of the finish. Floor sanding is performed with large belt or drum sanders. Like floor screening, floor sanding creates substantial quantities of dust. As is the case with floor screening, the large quantity of dust will rapidly plug a dry filter of a dust collection system. In addition, the presence of wood in the sanding dust causes foaming in a liquid filter medium severely limiting its effectiveness. Anti-foaming chemicals can reduce the foaming, but the chemicals are only partially effective. Further, adding chemicals to the liquid filter medium significantly increases the cost of floor finishing because the large quantity of dust requires the liquid medium and the anti-foaming chemicals be frequently replaced.
[0008] What is desired, therefore, is an apparatus for converting a standard floor machine to a floor screening machine and an effective, large capacity dust collection system suitable for floor screening and sanding operations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] [0009]FIG. 1 is a perspective view of a floor machine.
[0010] [0010]FIG. 2 is a perspective view of a floor machine with the floor screening attachment and an elevation view of a dust collection vacuum system.
[0011] [0011]FIG. 3 is a perspective view of the floor screening attachment.
[0012] [0012]FIG. 4 is a cross section of the floor screening attachment of FIG. 3 along line A-A.
[0013] [0013]FIG. 5 is a plan view of the bottom of the facing of the sanding block of the floor screening attachment.
[0014] [0014]FIG. 6 is a cross section of a floor screening attachment of an alternative construction.
[0015] [0015]FIG. 7 is a schematic representation of a cross section of the dust collection vacuum system.
[0016] [0016]FIG. 8 is a view of dust collection system including a dust collection unit for floor machine.
[0017] [0017]FIG. 9 is a cross section of a dust collection unit of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Referring to FIG. 2, the floor screening system 40 of the present invention generally comprises a floor machine 42 , a floor screening attachment 44 , and a dust collection vacuum system 46 connected to the floor screening attachment 44 by a hose 48 . The floor machine 42 comprises a chassis 50 enclosing a motor 52 and a gear train 54 . The chassis 50 also provides a connection point for a handle 56 for operator control of the floor machine 42 . Typically, floor machines are equipped with a pair of wheels 58 attached to the chassis 50 and arranged to engage the floor when the floor machine 42 is tipped toward the handle 56 . The wheels 58 provide a convenient support for the floor machine when moving between work areas. The floor screening attachment 44 is fitted with wheels 60 mounted for rotation and attached to the shroud 72 . Since the screening attachment 44 elevates the chassis 50 , the wheels of the floor machine 58 may not be useful for moving the floor machine when the screening attachment is in place. The wheels 60 can be used for moving the floor machine 42 when it is equipped with the screening attachment 44 .
[0019] Referring to FIGS. 2, 3, and 4 , the floor screening attachment 44 comprises generally a pad driver 70 and a shroud 72 mounted for rotation independent of the pad driver. The pad driver 70 includes a pad driver shaft 74 having a first end providing an interface to the powered drive shaft 62 projecting from the gear box of the floor machine 42 . The interface between the pad driver shaft 74 and the drive shaft 62 of the floor machine is dictated by the design of the floor machine but, by way of example only, may be provided by intermeshing projections as illustrated in FIG. 4. A circular sanding block 76 is affixed to the second end of the pad driver shaft 74 . The sanding block comprises a backing plate 78 and a facing 80 . The backing plate 78 is a disk that supports the facing 80 and controls distortion of the facing which could cause unevenness of the screened surface. A bearing and seal 82 is affixed to the upper surface of the backing plate 78 and engages complementary bearing and sealing rings 84 and 86 attached to the shroud 72 .
[0020] The shroud 72 of the screening attachment 44 includes a connector 88 for a hose 48 to the dust collection vacuum system 46 . The bearing and sealing ring 82 , 84 , and 86 , in conjunction with the shroud 72 , form a plenum 75 around the periphery of the backing plate 78 in communication with the connector 88 . The pressure differential created in the plenum 75 by the vacuum source draws air through an approximately annular aperture between the shroud 72 and the backing plate 76 to move air entrained dust particles to the hose connection outlet 88 . The shroud 72 may be extended by a skirt 73 , such as a brush type screen or flexible element, to aid in confining dust expelled from the perimeter of the screen 90 . Preferably the skirt 73 comprises a flexible, non-porous material such as rubber or plastic that stops short of the floor to permit air to flow into the plenum 75 . However, the skirt 73 may comprise a brush or other porous material to permit air to flow into the plenum 75 .
[0021] The screen 90 typically comprises an open mesh cloth coated with silicon carbide or another abrasive. When the sanding block 76 is rotated, friction between the facing 80 and the screen 90 causes the screen to rotate. To reduce slippage between the screen 90 and the facing 80 and resulting erosion of the abrasive from the screen 90 the present inventors concluded that facing should utilize a material having a high coefficient of friction with the mesh material. Further, the inventors concluded that when air is drawn through the prior art felt sanding block facing the passages in the felt quickly plug with dust limiting the effectiveness of the dust collection system. As a result, dust becomes trapped between the mesh of the screen and the felt facing. Since the vacuum system cannot draw air and dust through the plugged felt, the dust collection system is limited to collecting dust that migrates to the edge of the screen disk. The facing 80 of the sanding block 76 of the present invention comprises a plurality of spaced apart raised surfaces 92 . As illustrated in FIG. 5, the spaced apart, raised surfaces 92 are separated by surfaces 94 having a portion in relief of the raised surfaces 92 to create a pattern of channels through which air and entrained dust particles can migrate to reach the perimeter of disk for collection by the vacuum system. Rubber compounds, synthetic rubbers, plastics, and similar materials provide high friction between the screen 90 and the facing to reduce slippage and erosion of the abrasive, resilience to protect the sanded surface, and are moldable to form the plurality of spaced apart raised surfaces 92 useful in promoting air flow and dust collection.
[0022] [0022]FIG. 6 illustrates an alternative construction for the floor screening attachment 44 of the present invention. The floor screen 202 is supported by a sanding block 201 (illustrated by a bracket) comprising a wooden backing plate 204 and a facing 80 as described above. To improve conformance of the screen 202 with the floor surface, a compliant pad 206 may be placed between the facing 80 and the wooden backing plate 204 . The sanding block is driven by a shaft 208 affixed to a flange 210 that is attached to the wooden backing plate with screws 212 . The opposite end of the shaft 208 is affixed to a second flange 214 that is attached to riser 216 and a clutch plate 218 by screws 220 . The drive shaft 62 of a floor machine 42 engages the clutch plate 218 to drive the sanding block 201 . A shroud 222 with a skirt 224 forms a plenum 226 about the exposed periphery of the sanding block 201 . A vacuum source (not illustrated) attached to the shroud draws air contaminated with dust from the plenum 226 . A pair of bearings having flanged outer cases 228 and 230 attached to the shroud 222 with screws 232 , permit the shaft 208 to rotate independent of the shroud 222 .
[0023] Referring to FIG. 7, the vacuum system 46 of the present invention is connected to the screening attachment 44 by a hose 48 . The vacuum system 46 comprises generally a motor enclosure 100 and a container or cannister 102 . A vacuum source 104 (typically a motor and a fan) creates a pressure differential between the inlet 106 to the cannister and an air outlet 107 . A volume of liquid 108 (typically water) fills the cannister to a liquid level 110 . The inlet 106 for contaminated air drawn from the screening attachment is submerged in the liquid 108 . As the contaminated air 112 (indicated by an arrow) emerges from the submerged inlet 106 particles entrained in the air are wetted by and trapped in the liquid 108 . However, the surface tension of the liquid 108 also results in bubbles 114 and particles in the air trapped within the bubbles may not be wetted by the liquid. The bubbles 114 rise to the surface 110 of the liquid 108 . Particles within bubbles collapsing on the surface 110 of the liquid are wetted and trapped in the liquid 108 . Air and liquid are drawn up through a mixer 116 which further mixes the liquid and air further wetting entrained particles. The mixer 116 comprises a larger diameter tube concentric with the tube 118 leading from the hose to the inlet 106 . The mixture of air, liquid, and particles exits the mixing chamber 116 and enters a separator 118 . The separator 118 comprises a hollow toroid of generally circular cross-section surrounding the tube 118 leading to the inlet 106 . As the mixture of air and liquid is deflected by the curved walls of the separator and forced to change direction 120 (indicated by an arrow) additional bubbles are collapsed by the walls and additional particles are wetted by the liquid. As the moving mixture is further forced around the curved interior of the separator 118 , the heavier liquid and wetted particles are forced to the walls of the separator by centrifugal force. A slurry of liquid and wetted particles exits the mixing and separation chamber 118 at an exit aperture 122 and drops under the influence of gravity into the volume of liquid 108 in the bottom of the cannister 102 . Filtered air 124 exiting the separator chamber 118 is drawn to the outlet 107 by the pressure differential produced by the vacuum source 104 . Before exiting the cannister 102 , the air may also be filtered by a secondary dry filter 126 positioned in the air flow path. The large volume of liquid 108 in the cannister 102 provides substantial capacity to absorb dust produced by the screening operation permitting the work to continue without the need to change or clean filters. Liquid filtration avoids filter clogging encountered with industrial vacuums during screening.
[0024] The vacuum system 46 provides substantial capacity for capturing dust produced by floor screening operations and can be used for other floor finishing operations, such as sanding. The wood of a new floor must be sanded to prepare the surface for finishing. Likewise, if an existing finish is severely worn sanding may be necessary to restore the surface for refinishing. Sanding can be performed with floor screening machines, drum sanders and belt sanders and produces as great or greater quantities of dust than floor screening. Further, the wood in the sawdust produced by floor sanding aggravates foaming of a liquid dust filter medium substantially reducing the effectiveness of liquid in trapping dust. Anti-foaming chemicals can be added to the liquid to reduce the foaming but the chemicals are only partially effective. In addition, the absorption of large quantities of dust requires frequent disposal of the liquid medium and the anti-foaming chemicals substantially increasing the cost of sanding. Referring to FIG. 8, to increase the dust containment capacity of the system and reduce problems created by foaming of a liquid dust filter medium during sanding operations, the floor finishing system of the present invention may include a dust removal unit 240 to remove a substantial portion of the dust from the air stream before reaching the vacuum 46 . The components of the system having counterparts illustrated in FIG. 2 and performing the same functions are assigned like numerals. The vacuum 46 draws dust laden air from the screening attachment 44 through the hose 242 into the dust removal unit 240 . A hose 244 connects the dust removal unit 240 to the vacuum 46 . A belt or drum sander may be used instead of a floor machine for sanding operations. Sanders and other floor finishing machines may include a fan to draw air from the vicinity of the working portion of the sanding or tool and expel it through the hose 242 to the dust removal unit 240 eliminating the need for the separate vacuum source 46 .
[0025] Referring to FIG. 9, the dust removal unit 240 comprises generally a dust collection tank 250 sealed with a lid 252 . Sawdust laden air is drawn from the vicinity of the sanding element or tool of a floor screening machine, sander, or other floor finishing tool through the hose 242 to an inlet tube 254 of the dust removal unit 240 . Air contaminated with dust flows through the hose 242 into the dust removal unit 240 as a result of an air pressure differential between the inlet tube 254 and an outlet tube 256 . The air pressure differential can be created by an air moving device, such as a vacuum source 46 connected to the outlet tube 256 by a hose 244 as illustrated in FIG. 8 or by a fan at the floor finishing machine.
[0026] Air including suspended dust entering the dust removal unit 240 is directed toward the underside of the top surface of the lid 252 into a first passage 258 . The first passage 258 is bounded by the underside of the lid 252 and an upper surface of a secondary chamber structure 260 suspended generally centrally in the lid 252 by attachment to the inlet 254 and outlet 256 tubes. The secondary chamber structure 260 is generally a hollow cylinder with a closed upper end. The velocity of the air is substantially reduced when the air flow is redirected by the surface of the lid 252 and diffused in the first passage 258 which has a cross-section substantially larger than the inlet tube 254 . As a result of the pressure differential between the inlet tube 254 and outlet tube 256 air flows to a second passage 264 in fluid communication with the first passage 258 . The second passage 264 has a cross-section greater the first passage 258 causing the dust laden air to further decelerate. As the velocity of the air decreases in the second passage 264 the dust particles can no longer be supported by the air and fall to the bottom of the tank under the influence of gravity. The air exiting the second passage 264 is further decelerated as its direction is changed to enter a third passage 266 defined by the interior surfaces of the secondary chamber structure 260 . The further reduction in velocity releases substantially all of the dust remaining suspended in the air. The air exits the third passage 266 through the outlet tube 256 .
[0027] For floor refinishing operations, the system of the present invention provides a floor machine that can be quickly and conveniently converted to a floor screening machine. An effective dust collection system for the floor screening machine eliminates air borne contaminants and messy wet screening operations. The system can also include a dust collection unit to remove dust produces by floor sanding which can produce foaming of a liquid dust filter medium.
[0028] All the references cited herein are incorporated by reference.
[0029] The terms and expressions that have been employed in the foregoing specification are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims that follow. | Sanding and screening are steps in floor finishing that produce large quantities of fine dust which is difficult to remove and which plugs porous filter elements of dust collection systems. Dust collection is enhanced with a floor screening attachment for a floor machine. A vacuum system with a liquid filtering medium is provided to collect dust produced during screening. A dust collection unit is also disclosed to collect and separate sawdust produced by sanding which can cause foaming of a liquid filter medium. |
FIELD OF THE INVENTION
[0001] The invention relates to a power manager.
[0002] The invention also relates to an electronic system comprising an electronic device.
[0003] The invention also relates to a method for managing the power supplied to an electronic device.
[0004] The invention also relates to a computer program product.
BACKGROUND OF THE INVENTION
[0005] In modern electronic devices, power management is becoming ever more important. For example, battery operated devices acquire more computationally intensive features, such as playing video clips. Such computationally intensive features require more power. Yet, at the same time there is a demand for longer stand-by and operating times. Also, for environmental reasons it is important not to needlessly dissipate power.
[0006] To reduce the energy use, i.e. the power consumption, of an electronic device, such as an integrated circuit (IC), Dynamic Power Management (DPM) is used. DPM is a technique that dynamically scales the power delivered to an electronic device to such a level that it just meets the varying performance levels required for an application using the electronic device.
[0007] The workload of an electronic device changes dynamically while the application is using the electronic device. To scale the power delivered to the electronic device the amount of power needed in the future needs to be predicted. As the future power needs of an electronic device are more accurately predicted, the more power can be saved.
[0008] One way of controlling the power for a computer running an application on top of an Operating System (OS) is based on the number of processor clock cycles that were spent in a particular task in the past. The number of clock cycles that were spent in a particular task is determined by the OS. The problem is that determining the number of cycles spent in a task is only triggered by some OS related events, for example, when switching tasks, or when an OS timer tick occurs. Determining the number of cycles spent in a task cannot be done more frequently, because the OS runs in software. As a result the resolution of the data produced by an OS is too low to identify patterns in the power consumption on a time scale with a finer granularity than that allowed by a software program, such as an OS.
SUMMARY OF THE INVENTION
[0009] It is a problem of the prior art that workload monitoring for power supply controlling is too inaccurate.
[0010] It is an object of the invention to improve the controlling of power supplied to an electronic device.
[0011] The object is achieved by a power manager according to the invention. The power manager is operative to monitor a hardware monitor during a monitoring time period. The hardware monitor is coupled to an electronic device. The electronic device has a workload during operational use. The hardware monitor is operative to indicate the workload of the electronic device. The power manager is operative to control power supplied to the electronic device in dependency on the monitoring.
[0012] When an electronic device is operative sometimes its workload is high and sometimes its workload is low. The power management of an electronic device could be improved if a better prediction could be made of its workload. In that case the supply of power to the electronic device can be reduced when its workload is low.
[0013] To predict the future workload of an electronic device, accurate data must be collected to base this prediction on. Such accurate data can be obtained from a hardware monitor. By basing power control on accurate data of the workload, a better control of the power supply is achieved. As a result the power to the device will be reduced, resulting in power savings. In case the device is battery operated, the batteries will drain slower.
[0014] Embodiments of an electronic device whose workload can be monitored include, e.g. an integrated circuit (IC), or an electro-mechanical device, such as a stepper motor. Examples of electronic devices also include computation devices or data handling devices, such as a video processing unit in a mobile phone, etc.
[0015] In particular, a central processing unit (CPU) operative to execute a computer program, i.e. software, is an electronic device. Also, when a CPU executes an application, such as a music application or video application, sometimes the workload of the CPU will be high and sometimes the workload will be low.
[0016] The workload can be a direct representation of the amount of work performed by the electronic device in a time period. For example, the workload can be the quotient of the number of productive cycles and the total number of cycles in a time period. The workload can also be the amount of power that is consumed by the electronic device.
[0017] During operation, the electronic device needs power. The amount of power needed by the electronic device depends on the operation the electronic device is carrying out. In normal operations, changing the power supplied to the electronic device influences only the speed with which the electronic device operates. Changing the power supplied to the electronic device operations does not, in itself, influence the operations performed by the electronic device.
[0018] The hardware monitor is operative to indicate the workload of the electronic device, at a fine-grained resolution. For example, for a clocked electronic device, the resolution may be on a per cycle basis.
[0019] If the electronic device is a CPU, the hardware monitor indicates, for example: if the CPU is currently executing a No Operation (NOP) instruction, if the CPU is in sleep mode or idle mode. Some models of CPU can go in to an idle mode by blocking their output buffer. The hardware monitor may monitor the blocking of an output buffer.
[0020] A typical example of a hardware monitor is a so called hardware event counter, also known as hardware performance counter, also known as Performance Monitoring Unit.
[0021] A hardware event counter is typically comprised in a processor, and is known in the art. Most modern processors offer hardware event counters for monitoring performance events related to the interaction of applications with special subunits of the processor. See for example: Intel Corporation. Intel Architecture Software Developer's Manual. Volume 3 : System Programming Guide , 2004; SGI. Topics In Irix Programming, Chapter 4; A. Singhal and A. J. Goldberg. Architectural Support for Performance Tuning: A Case Study on the SPARCcenter 2000. ACM SIGARCH Computer Architecture News, Proc. of the 21 st Annual International Symposium on Computer Architecture (ISCA 94), 22(2), April 1994; L. Smolders. PowerPC Hardware Performance Monitoring. Technical report, AIX Performance, IBM Server Group, November 2001; L. Smolders. System and Kernel Thread Performance Monitor API Reference Guide . IBM, RS/6000 Division, 2001.
[0022] Power may be controlled by moving a state machine to certain states. In particular, power may be controlled by turning off an idle electronic device.
[0023] Power can be controlled by changing the routing of the power supply. The power can also be controlled by instructing other units, e.g., a power controller, to reduce or increase the amount of power routed to the electronic device.
[0024] In a practical embodiment of the invention, the power manager is operative to control the power by controlling the clock frequency on a clock line connected to the electronic device.
[0025] In a practical embodiment of the invention, the power manager is operative to control the power by controlling the supply voltage of the electronic device.
[0026] The invention is particularly advantageous if the workload is substantially periodic.
[0027] If the workload is periodic the prediction of future workload is simplified. For periodic workloads the past is a good indication of the future. If it can be detected that the application is, or currently is, periodic the prediction of the workload can be improved.
[0028] A problem with obtaining workload numbers using the OS is that it only gives a CPU workload number, e.g., in a percentage. A power manager, using such a number cannot determine when a new period of high workload begins, nor can the power manager determine what the frequency or time period of a workload's repetition is. Detecting the exact time period or exact period's phase, is not possible using OS based numbers.
[0029] The power manager may operate as follows: detecting a workload frequency of the periodic workload, e.g., detect the time that elapses between a first and a second workload period; detecting a workload phase in the periodic workload, e.g., find the point in the periodic workload where the load starts.
[0030] In a preferred embodiment of the invention the power manager is operative to detect a rising edge in the monitored indicated workload and the power is controlled in dependency on the detected rising edge.
[0031] By signaling a sudden rise, i.e. a rising edge, in the workload of the electronic device, the beginning of a period of high workload can be detected. To detect an edge the edge detection must be based on accurate data.
[0032] Signaling a sudden rise is detected, e.g., as follows: the value indicated by the hardware monitor rises at least a predetermined percentage in a predetermined length of time; the value of the hardware monitor rises at least a predetermined amount in a predetermined length of time; the fraction of the time the hardware monitor indicates values above a certain value increases in a predetermined time period.
[0033] Signaling a sudden rise can also be done by first calculating a running average of the measurements of the hardware monitor, and second detecting a sudden rise in the running average. The latter technique is especially useful if the hardware monitor reports binary values.
[0034] In a practical embodiment of the invention, the power manager is operative to detect a falling edge in the monitored indicated workload; the power is controlled in dependency on the detected falling edge.
[0035] By signaling a sudden decrease, i.e. a falling edge, in the workload of the electronic device, the end of a period of high workload can be detected. To detect an edge, the edge detection must be based on accurate data.
[0036] In a practical embodiment of the invention, the power manager is operative to detect a further rising edge in the monitored indicated workload; the power manager is operative to predict a future edge in dependency on the difference between the rising edge and the further rising edge; the power is controlled in dependency on the predicted future edge.
[0037] When at least two rising edges have been determined, a prediction can be made, by extrapolating, when a future edge will occur. For example, a future edge can be predicted for the time of the further rising edge plus the difference in time between the occurrences of the further rising edge and the rising edge.
[0038] The power can be controlled in dependency on the predicted future edge, by setting the level of supplied power to a level needed in the time interval just after the past edges.
[0039] In a practical embodiment of the invention, the power manager is operative to detect a further falling edge in the monitored indicated workload; the power manager is operative to predict the future edge in dependency on the difference between the falling edge and the further falling edge; the power is controlled in dependency on the predicted future edge.
[0040] When at least two falling edges have been determined, a prediction can be made, by extrapolating, when a future edge will occur. For example, a future edge can be predicted for the time of the further falling edge plus the difference in time between the occurrences of the further falling edge and the falling edge.
[0041] The power can be controlled in dependency on this predicted future edge, by reducing the level of the supplied power to a level needed in the interval just after past falling edges.
[0042] In preferred embodiment of the invention, the power manager is operative to select a next monitoring time period adjusted around the predicted future edge; the power manager is operative to monitor the hardware monitor during the next monitoring time period.
[0043] Once the power manager can predict a future falling or rising edge, the power manager may decide to stop continuous monitoring. By selecting a next monitoring time period, wherein a predicted edge falls, the power manager can verify if its predictions are correct. There is no need for the next monitoring time period to contain the immediately following predicted edge, instead, the power manager may skip one or more predicted edges before monitoring again. Measuring from time to time may be useful to correct for a drift in the occurrence of the edges.
[0044] In a practical embodiment of the invention the power manager is operative to produce a monitoring trace for tracking the hardware monitor; the power manager is operative to determine a workload frequency in the workload and a workload phase with respect to a reference time point, based on the monitoring trace; the power manager is operative to predict the workload based on the workload frequency and the workload phase; the power is controlled in dependency on the predicted workload.
[0045] A monitoring trace is a recorded representation of a history over a time period of the values indicated by the hardware monitor.
[0046] The power manager can create a trace by temporarily storing a number of values produced by the hardware manager. The trace can be analyzed too, for periodic patterns, for example, by detecting edges. Such periodic patterns have a frequency, i.e. workload frequency. A point where a period of high workload starts can be determined with respect to a reference point, i.e. the workload phase. Once it is known when a period of high workload starts and how often the period repeats, the future workload can be predicted.
[0047] In a practical embodiment of the invention the hardware monitor is integrated in the power manager.
[0048] The electronic system according to the invention comprises a power manager according the invention and an electronic device having a workload during operational use; and a hardware monitor coupled to the electronic device and operative to indicate the workload of the electronic device.
[0049] In a preferred embodiment of the system according to the invention the electronic system is configured for having the workload substantially periodic.
[0050] An electronic system according to the invention can be accommodated in an electronic mobile data handling device.
[0051] It is a problem that the operational use of electronic mobile data handling devices are constrained by their power needs. It is particularly advantageous to reduce the power consumption of an electronic mobile data handling device. Reducing the power consumption of a device will give the device, e.g., a longer standby time and/or a longer playing time.
[0052] Embodiments of an electronic mobile data handling device include a mobile phone, a personal digital assistant (PDA), an mp3 player, a portable video playing device, a personal navigation device, etc.
[0053] The method for managing the power supplied to an electronic device, comprises the following steps: monitoring a hardware monitor during a monitoring time period; controlling power supplied to the electronic device in dependency on the monitoring.
[0054] In a preferred embodiment of the method for managing the power supplied to an electronic device a representation of the monitoring is stored in a monitoring trace. The method comprises the additional steps of: detecting at least two edges in the monitoring trace; determining a workload frequency and a workload phase with respect to a reference time point, based on the monitoring trace; predicting the workload based on the workload frequency and workload phase. The controlling is carried out in dependency on the predicting.
[0055] A preferred embodiment of the method for managing the power supplied to an electronic device comprises the following steps: predicting a future edge; selecting a next monitoring time period adjusted around the predicted future edge; monitoring the hardware monitor during the next monitoring time period.
[0056] The computer program product comprises computer code for performing the method according to the invention.
[0057] It is to be noted that the paper by Christos D. Antonopoulos and Dimitrios S. Nikolopoulos, “Using Hardware Event Counters for Continuous, Online System Optimization: Lessons and Challenges” discloses a method for using hardware event counters to adapt the scheduler of an operating system (OS).
[0058] It is to be noted that U.S. Pat. No. 4,823,292: “Data processing apparatus with energy saving clocking device”, incorporated herein by reference, discloses a data processing apparatus, having a data processing element with an operating mode and a stop mode. The energy consumption of the device can be reduced, by switching between the two modes. U.S. Pat. No. 4,823,292 does not make use of a hardware monitor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0059] The invention is explained in further detail, by way of example and with reference to the accompanying drawing, wherein:
[0060] FIG. 1 is a block diagram showing an embodiment of an electronic system according to the invention.
[0061] FIG. 2 . is a graph showing a workload trace of a periodic application.
[0062] FIG. 3 . is a graph illustrating the importance of determining a correct workload phase.
[0063] FIG. 4 . is a block diagram showing an embodiment of a power manager
[0064] FIG. 5 . is a block diagram showing a further embodiment of an electronic system according to the invention.
[0065] FIG. 6 . is a flow chart illustrating a method according to the invention.
[0066] Throughout the Figures, similar or corresponding features are indicated by same reference numerals.
LIST OF REFERENCE NUMERALS
[0000]
100 an electronic system
102 an electronic device
104 a hardware monitor
106 a power manager
200 a Power Management Unit (PMU)
202 a workload frequency and workload phase detector
204 a workload predictor
206 a workload frequency transport
208 a workload phase transport
210 a workload transport
500 a trace generator
502 a power manager logic
508 a power controller
510 a Dynamic Voltage and Frequency Scaling (DVFS) Driver
512 an application memory
1002 monitoring a hardware monitor ( 104 ) during a monitoring time period and store in a monitoring trace;
1004 detecting at least two edges in the monitoring trace;
1006 determining a workload frequency and a workload phase with respect to a reference time point, based on the monitoring trace;
1008 predicting the workload based on the workload frequency and workload phase;
1010 controlling the power supplied to the electronic device in dependency on the predicting.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0087] While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one or more specific embodiments, with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and not intended to limit the invention to the specific embodiments shown and described.
[0088] In FIG. 1 a block diagram is shown of an embodiment of an electronic system ( 100 ) according to the invention.
[0089] The system ( 100 ) comprises an electronic device ( 102 ), a hardware monitor ( 104 ) and a power manager ( 106 ). In this embodiment the electronic device ( 102 ) comprises the hardware monitor ( 104 ), although this is not necessary.
[0090] The hardware monitor ( 104 ) is configured to indicate the workload of the electronic device ( 102 ). The power manager ( 106 ) is arranged to be able to read the hardware monitor ( 104 ) via a connection. The power manager ( 106 ) is arranged to control the power supplied to the electronic device ( 102 ).
[0091] During operation, the hardware monitor ( 104 ) indicates values that represent the workload of the electronic device ( 102 ). For example, the hardware monitor ( 104 ) may be a one bit register indicating if the electronic device ( 102 ) is currently active or idle. The power manager ( 106 ) reads the contents of the hardware monitor ( 104 ) and uses it to predict the future workload of the electronic device ( 102 ). Based on the future workload of the device ( 102 ), the power manager ( 106 ) decides the amount of power needed by the electronic device ( 102 ). For example, the power manager ( 106 ) may calculate the clock frequency needed by a processor to finish the workload in time; the power manager ( 106 ) can calculate a supply voltage that is just sufficient to sustain the clock frequency.
[0092] The electronic device ( 102 ) has a periodic workload. The hardware monitor ( 104 ) is coupled to the electronic device ( 102 ) and indicates the workload of the electronic device ( 102 ). The power manager ( 106 ) monitors the hardware monitor ( 104 ). The power manager ( 106 ) makes a prediction of the future workload and on the basis of the prediction, the power supplied to the electronic device ( 102 ) is regulated.
[0093] The power manager ( 106 ) makes the workload period prediction by means of detecting edges. The power manager ( 106 ) synchronizes its operation with the detected workload periods. The power manager ( 106 ) determines the start of a rising edge, and the frequency of rising edges. Ideally also the length of the workload period is calculated.
[0094] The power manager ( 106 ) does not need to continuously monitor the hardware monitor ( 104 ). Once the power manager ( 106 ) has predicted an edge, the power manager ( 106 ) will only monitor in a time interval around the moment of occurrence of the predicted edge to check its prediction, and to calibrate, i.e. re-adjust, if necessary. Re-adjustment may be necessary in case of drift.
[0095] The power manager ( 106 ) can be made using dedicated hardware, such as electronic circuits that are configured to perform the controlling and monitoring, or the power manager ( 106 ) can be made from generic hardware controlled using dedicated software, or the power manager ( 106 ) may comprise a combination of dedicated hardware and generic hardware.
[0096] Typically, the power manager ( 106 ) will control the power through an intermediate, power management unit ( 200 ) (not shown in FIG. 1 ), e.g., by sending information about clock frequency and/or supply voltage to the power management unit ( 200 ).
[0097] Instead of reporting the workload of each cycle, the hardware monitor ( 104 ) may report the workload in a short time period combined in a single number, e.g. the average or total workload. For example, the hardware monitor ( 104 ) may report the number of active cycles of a CPU in a short time period. A time period is short if the resulting combined values given by the hardware monitor ( 104 ) give sufficient resolution to view the periodicity of the workload.
[0098] In FIG. 2 a graph is shown of a workload trace of a periodic application. The graph shows an example workload trace, for a periodic application, namely video decoding, running on embedded ARM9 CPU.
[0099] In order to predict processor workload of a periodic application, with a varying workload, e.g. a varying number of active CPU cycles needed per period, a correct measurement of the workload for the current period has to be performed.
[0100] Measuring this workload during the correct time frame, e.g., one period, in software or, e.g., an operating system, is not possible with sufficient time resolution. When using hardware event registers or trace registers that measure CPU occupation on a very fine grain, a more precise synchronization is possible. In the invention, application workload is measured by an independent observer. Ideally, the period of the measurement is equal to the workload period, and the beginning of the measurement period is synchronized with the beginning of the workload period.
[0101] For applications that are not CPU-bound, i.e. which do not require a constant CPU workload of around 100%, power consumption can be reduced by running the CPU at a clock frequency and voltage that is just adequate to perform the requested computation in time. The CPU workload can be computed as the fraction of the time the CPU is busy executing instructions, or alternatively, as a ratio of a number of clock cycles used for computation to the total number of available clock cycles for a defined period.
[0102] The controlling of the power supplied to the CPU can be done, e.g., via control of the clock frequency and/or voltage. For example, power can be controlled through the use of Dynamic Voltage and Frequency Scaling (DVFS) which may be controlled from software and/or from hardware.
[0103] For periodic applications, like video playback, it is possible to control power supplied to the CPU, by observing and predicting the workload of the CPU.
[0104] In operating systems, such as Linux, the CPU workload is measured by the OS. In Linux this is done by the timer tick interrupt: at each timer tick, typically each 1, 4 or 10 milliseconds (msec), the CPU is interrupted and the code that was interrupted is classified. The code class is one of the following types: User, System, Nice or Idle. The type “User” stands for running applications, System means executing a system call. The type “Nice” stands for batch jobs being processed. And the type “Idle” means the CPU is not performing any useful instructions, e.g., the CPU might be halted. At each timer tick, one unit value is added to the value counted by the corresponding class counter. To determine the workload during a certain period, consisting of several timer ticks, the sum of ticks spent in “User”, “Nice” and “System” has to be divided by the total number of ticks in this period to get the CPU workload during this period. Typically the timer tick frequency is between 100 to 1000 Hz. Since the timer tick frequency is rather low, compared to the CPU speed, measuring workload is a trade-off between timing and value accuracy, e.g., measuring during 10 ticks yields a 10% accurate value every 10 timer ticks; for 1% accuracy the measuring period should be some 100 timer ticks, meaning a measuring period of 100, 250 or 1000 msec, much longer than, e.g., the frame rate for video playback. As a result these workload numbers reported by operating system software are insufficient for fine-grained power supply control.
[0105] Most modern microprocessors are equipped with special, on-chip hardware, e.g., hardware event counters, that can monitor performance events related to the interaction of applications with specific subunits of the processor. The results of performance monitoring are written to registers that allow analyzing the performance of various parts of the CPU core.
[0106] These hardware event counters give a hardware-based measure of processor workload with a greater accuracy and/or sampling resolution than is possible in software. These counters operate in the CPU clock frequency domain, which is in the order of nanoseconds, rather than in the OS timer tick domain. Since the workload frequency is necessarily lower than the CPU clock frequency, the sampling frequency of the hardware monitor can be kept sufficiently high to detect workload periods. The registers can be programmed to operate fairly autonomously, this gives the advantage that processor workload can be measured with greater timing accuracy and without noticeable performance impact on the CPU.
[0107] For instance, the Intel Pentium4 processor has 44 trace(event) registers of which 18 can be selected to provide real-time performance data, that measure. For example, a register can monitor: cache hits, branch prediction logic efficiency, and the time during which the processor is not idle. The time that the processor is not idle is a direct equivalent of the processor workload and is measured with a much higher time resolution than an operating system could do. The resolution of the hardware event counter is in the order of nanoseconds compared with the millisecond range of the OS. The CPU can autonomously output trace data values to main memory and generate an interrupt when certain events, such as counter overflow, occur.
[0108] In FIG. 3 , a graph is shown illustrating the importance of determining a correct workload phase.
[0109] In order to correctly predict the CPU workload, the current CPU workload must be known. For accurate workload measurements two characteristics of the application are needed. The first characteristic relates to the frequency of the workload variation, i.e. the workload frequency. Instead of the workload frequency, a value that is representative for the workload frequency can be used, e.g., the length of the period. For example, the workload frequency of a video playback application depends on the frame rate. The second characteristic relates to the workload phase of the workload, i.e. the start time of a repeated period of high workload of the application. For example, for a video playback application the workload phase would typically correspond to the start of the processing of a video frame.
[0110] These characteristics can be derived by observing the workload of the CPU. For this purpose, the CPU workload must be measured.
[0111] The graph of FIG. 3 is a detail of the workload graph of a periodic application. The problem involved in trying to control power, e.g., by predicting the workload of an application with a separate independent power manager ( 106 ), is that both the workload frequency, i.e. the frequency of the periodicity of the application, and the workload phase, that is the start time of a period, of the workload of the application are not known beforehand.
[0112] Even if the workload frequency is discovered, detecting the workload phase is important for a correct measurement of the workload. The graph shown in FIG. 3 , illustrates the importance of synchronization of the measurement period with the workload period.
[0113] First the workload is measured during a correct period, that is between ‘A’ and ‘B’, which lasts 25 cycles, from 5 till 30. The workload value measured is 10 cycles, or 10/25*100%=40%.
[0114] Next, suppose that the measurement is not properly synchronized with the workload period. For example, the measurement takes place between ‘C’ and ‘D’, which also lasts 25 cycles, from 13 to 38. This results in an incorrect value for the workload, namely 8, or 8/25*100%=32%, which is quite off.
[0115] Using the measurement obtained from the wrong period, results in supplying the CPU with too little power. As a result, the system ( 100 ) could malfunction.
[0116] By detecting a sharp rise in the workload fast enough, a workload predictor ( 204 ) can synchronize its prediction of the workload with the actual workload periods of the application.
[0117] In FIG. 4 , a block diagram is shown of an embodiment of a power manager ( 106 ).
[0118] The power manager ( 106 ) comprises a workload frequency and workload phase detector ( 202 ) and a workload predictor ( 204 ). The workload frequency and workload phase detector ( 202 ) is connected to the hardware monitor ( 104 ) for monitoring the hardware monitor ( 104 ). The signal representative of the workload is transported via a workload transport ( 210 ) from the hardware monitor ( 104 ) to the detector ( 202 ). The detector ( 202 ) estimates a workload frequency and a workload phase of the workload. If the detector ( 202 ) finds that the workload is not sufficiently predictable, the detector ( 202 ) disables the controlling of the power by the power manager ( 106 ).
[0119] Values obtained via the hardware monitor ( 104 ) can also be used by the workload predictor ( 204 ), via transport ( 210 ).
[0120] The detector ( 202 ) is connected to the workload predictor ( 204 ) via a workload frequency transport. The detector ( 202 ) is connected to the workload predictor ( 204 ) via a workload phase transport ( 208 ). The workload predictor ( 204 ) is configured for predicting the workload of the electronic device ( 102 ) on the basis of the workload frequency and the workload phase.
[0121] The workload predictor ( 204 ) determines on the power needed by the electronic device ( 102 ) on the basis of its predictions. The workload predictor ( 204 ) sets a frequency and a level of supply voltage and forwards these values to a Power Management Unit (PMU) ( 200 ). The unit ( 200 ) is configured for controlling the power supplied to the electronic device ( 102 ), in dependency on the information forwarded to it by the workload predictor ( 204 ).
[0122] The Power Management Unit (PMU) ( 200 ) sets a supply voltage based on the Low Drop Out (LDO) Regulator, a DC/DC inductance voltage regulator, or any other suitable voltage regulator. The unit ( 200 ) may also comprise a clock generation unit (CGU). The CGU generates a clock based on a PLL, DDS or divider method, or other suitable clock generation method.
[0123] In order to have a workload predictor ( 204 ) independent of the application causing the workload, and such that a workload measuring period is equal to a workload period, and that both periods are in phase, it is advantageous to have workload frequency and workload phase detection as intermediate steps in the prediction.
[0124] Workload frequency and workload phase detection can be done by detecting edges in the workload values reported by the hardware monitor ( 104 ). This depends on the fine granularity, i.e. high frequency sampling, of the workload monitoring mechanisms, including the hardware monitor ( 104 ). The fine granularity can be obtained using, e.g., hardware performance counters that measure workload with a high resolution.
[0125] The fine granularity is important for precise determination of workload periods, for workload frequency calculation, and for detection of the workload phase. The workload phase is also important for synchronization of measurement periods with workload periods.
[0126] The frequency with which the workload is sampled by the hardware monitor ( 104 ) should be higher, preferably much higher, than the frequency of the workload periods. In particular, the sampling of the workload should be frequent enough to detect a rising edge of the measured workload.
[0127] Determination of a workload period, of a workload frequency and of a workload phase can be done using any suitable edge detection mechanism.
[0128] Ideally, the workload measurement period and workload period are synchronized through a synchronization mechanism.
[0129] The power manager ( 106 ) can be implemented in a software application. The power manager ( 106 ) can run in parallel to, and independent of, other applications on the device ( 102 ).
[0130] In FIG. 5 , a block diagram is shown of a further embodiment of an electronic system ( 100 ) according to the invention.
[0131] The system ( 100 ) comprises an electronic device ( 102 ). The electronic device ( 102 ) comprises a hardware monitor ( 104 ). The device ( 102 ) is connected to an application memory ( 512 ). The electronic device ( 102 ) is operative to execute an application, i.e. software, residing in the application memory ( 512 ). The system ( 100 ) comprises a power manager ( 106 ). The power manager ( 106 ) is partly implemented in power manager logic ( 502 ) and partly in a trace generator ( 500 ).
[0132] The power manager logic ( 502 ) comprises a workload frequency and workload phase detector ( 202 ), a workload predictor ( 204 ) and power controller ( 508 ).
[0133] The trace generator ( 500 ) is connected to the hardware monitor ( 104 ). The trace generator ( 500 ) is configured for transporting the values reported by the hardware monitor ( 104 ) in the form of a trace to detector ( 202 ). A trace may be represented as an array of values. The trace generator ( 500 ) can comprise a buffer, such as a First In First Out (FIFO) buffer or a circular buffer. The trace can be transported to detector ( 202 ) and/or predictor ( 204 ) by making the contents of the buffer available to the detector ( 202 ) and/or predictor ( 204 ).
[0134] The detector ( 202 ) determines a workload frequency and a workload phase, on the basis of edges detected in the traces. The workload frequency and the workload phase are transported to the workload predictor ( 204 ). The workload predictor ( 204 ) predicts the future workload of the electronic device ( 102 ). The predicted workload is reported to the power controller ( 508 ). The power controller ( 508 ) determines the amount of power that needs to be supplied to the electronic device ( 102 ) in a next period, by determining a clock frequency and a supply voltage level. The clock frequency and supply voltage, are forwarded to a Dynamic Voltage and Frequency Scaling (DVFS) Driver ( 510 ). The driver ( 510 ) is capable of setting the clock frequency and the supply voltage in the Power Management Unit (PMU) ( 200 ). The unit ( 200 ) is capable of setting the clock frequency and supply voltage of the electronic device ( 102 ).
[0135] The driver ( 510 ) is optional in this embodiment, the power controller ( 508 ) could also directly set the clock frequency and supply voltage in the Power Management Unit (PMU) ( 200 ).
[0136] This embodiment is especially suitable for, at least a partial implementation in power logic software. In particular, the power manager logic ( 502 ) and its components can be implemented in software. The software can be run on a CPU. Possibly the electronic device ( 102 ) is a CPU that could, among other tasks, execute the power logic software. The power logic software could also run on a CPU independent of the electronic device ( 102 ). The power logic software may reside in a memory, such as the application memory ( 512 ), or a different memory.
[0137] Alternatively, the power manager logic ( 502 ) could be implemented in hardware, such as in an IC, e.g. a CMOS circuit, or any other suitable electronic circuit.
[0138] An example of an electronic system ( 100 ) is a machine with a Pentium 4 processor running Linux. The trace generator ( 500 ) reads out the event and/or trace register ( 104 ) of the CPU ( 102 ) and generates a trace. The workload frequency and workload phase detector ( 202 ) detects rising edges in the workload, like the edges A and B in FIG. 3 . Preferably, the trace registers are set to measure processor occupation, for example, by monitoring trace the register ‘global_power_events’, on a regular basis. For this monitoring the application perfmon2 might be used, which is a hardware-based performance monitoring interface for Linux.
[0139] The power manager ( 106 ) is configured to initially synchronize with the detected workload edges. When the power manager ( 106 ) is synchronized with the detected workload edges, the power manager ( 106 ) can skip one or more workload periods before measuring again.
[0140] The workload values measured are forwarded to an edge detector. When the hardware monitor ( 202 ) and the edge detector ( 202 ) are both implemented in hardware, the edge detector ( 202 ) may interrupt the CPU on a detected rising edge. The predictor ( 204 ) can then precisely determine when a workload period starts. In this case the predictor ( 204 ) may be executed in software. This can be used to synchronize the workload phase of the first workload measurement. The workload period duration could be used to synchronize the measurement period. It could also be repeated from time to time to avoid drift between the measurement period and the workload period. On the other hand, the workload phase could be synchronized on every workload period. The latter is especially useful in case of high jitter in the workload period.
[0141] The invention is applicable in any system ( 100 ) that uses a microprocessor that, at least occasionally, runs periodic applications, or at least predictable applications.
[0142] In FIG. 6 a flowchart a method according to the invention is illustrated. The method comprises the following steps.
[0143] In a first step ( 1002 ), a hardware monitor ( 104 ) monitors during a monitoring time period and stores the results in a monitoring trace. In a next step ( 1004 ), at least two edges in the monitoring trace are detected. In a next step ( 1006 ), a workload frequency and a workload phase are detected, with respect to a reference time point and based on the monitoring trace. In a next step ( 1008 ), the workload is predicted based on the workload frequency and workload phase. In a next step ( 1010 ), the power supplied to the electronic device ( 102 ) is controlled in dependency on the predicting.
[0144] The present invention, as described in embodiments herein, may be implemented using a programmed processor executing programming instructions that are broadly described above in flow chart form that can be stored on any suitable electronic storage medium. However, those skilled in the art will appreciate that the processes described above can be implemented in any number of variations and in many suitable programming languages without departing from the present invention. For example, the order of certain operations carried out can often be varied, additional operations can be added or operations can be deleted without departing from the invention. Error trapping, enhancements and variations can be added without departing from the present invention. Such variations are contemplated and considered equivalent.
[0145] The present invention could be implemented using special purpose hardware and/or dedicated processors. Similarly, general purpose computers, microprocessor based computers, digital signal processors, microcontrollers, dedicated processors, custom circuits, ASICS and/or dedicated hard wired logic may be used to construct alternative equivalent embodiments of the present invention.
[0146] Those skilled in the art will appreciate that the program steps and associated data used to implement the embodiments described above can be implemented using disc storage as well as other forms of storage, such as, for example, Read Only Memory (ROM) devices, Random Access Memory (RAM) devices, optical storage elements, magnetic storage elements, magneto-optical storage elements, flash memory and/or other equivalent storage technologies without departing from the present invention. Such alternative storage devices should be considered equivalents.
[0147] While the invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications, permutations and variations will become apparent to those of ordinary skill in the art in light of the foregoing description. Accordingly, it is intended that the present invention embrace all such alternatives, modifications and variations as fall within the scope of the appended claims. | A power manager ( 106) and method for managing the power supplied to an electronic device is provided. Furthermore, a system wherein the power supplied to an electronic device is managed is provided. The power manager ( 106) is operative to monitor a hardware monitor ( 104) during a monitoring time period. The hardware monitor ( 104) is coupled to an electronic device ( 102). The electronic device ( 102) has a workload during operational use. The hardware monitor is operative to indicate the workload of the electronic device ( 102). The power manager is operative to control power supplied to the electronic device ( 102) in dependency on the monitoring. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of and device for attaching a connecting piece such as a tag pin which is used for connecting two members such as label or tag and an article of clothes to each other. More particularly, the invention is concerned with a method of and device for attaching a connecting piece by at first severing one by one a plurality of connecting pieces formed integrally in groups from a plastic, each group having a plurality of connecting pieces arranged in parallel relationship, and then attaching a severed connecting piece to an object, wherein the improvement resides in that the connecting pieces are successively fed to the severing position exactly even when the connecting pieces in the group are connected in an irregular pitch.
2. Description of the Prior Art
Recently, connecting pieces 1 made of a plastic as shown in FIG. 2 are used for connecting two members such as a label or tag and an article of clothes to each other. Each of the connecting pieces has a filament portion 1c to one end of which connected is a head portion 1a, while, to the other end, connected is a cross-bar portion 1b. The connecting pieces are formed integrally in the form of a belt or group 3 in which connecting pieces are connected to a common connecting rod 2 through respective connecting portions 1d. In use of the connecting pieces, the belt 3 is put into an attaching device which is adapted to severe connecting pieces successively one by one from the belt 3 and to attach the severed connecting piece 1 to two members such as a label or tag and an item of clothes thereby to connect these members to each other.
It is often experienced that, since the filament portion 1c is freely deflectable, the connecting pieces of a common belt 3 are inconveniently entangled with each other if the pitch P of the successive connecting pieces is too large. Also, when a multiplicity of belts 3 of connecting pieces are accomodated in a box or the like, the belts 3 are likely to be entangled with each other to hinder the attaching work.
These problems have been overcome, however, by reducing the pitch P of the connecting pieces to a size substantially equal to the thickness t of the head portion of the connecting piece. Consequently, the troubles attributable to the entanglement of the belts is eliminated to ensure a higher efficiency of the work. The reduction of the pitch P of the connecting pieces provides further advantages. For instance, the size of the mold for forming the belt is and, accordingly, the path leading to the cavity is shortened. In addition, the temperature spots of the mold is reduced to ensure the production of the belt of connecting pieces having no spot. Further, the forming pressure is decreased attributable to the shortening of the path to the mold cavity.
In the conventional attaching device for attaching the connecting piece, the arrangement is such that the belt 3 of the connecting pieces 1 is fed intermittently by each pitch by means of a gear of the same pitch as the pitch P of connecting pieces. Therefore, the conventional attaching device cannot be used for the belt 3 having connecting pieces disposed at such a small pitch. Another problem resides in that, for avoiding the feeding failure of connecting pieces, it is necessary to improve the pitch of the connecting pieces corresponding to the pitch of gear, so that the cavities of the mold for forming the belt or group 3 of connecting pieces have to be finished at an impractically high precision.
Further, the conventional attaching device can handle only the belt of connecting pieces which has been produced specifically for that attaching device and cannot operate with other belt. This is quite inconvenient from the user's point of view.
SUMMARY OF THE INVENTION
The present invention has been achieved under full consideration for overcoming the above described problems of the prior art.
It is, therefore, an object of the invention to provide a method of and apparatus capable of feeding connecting pieces such as tag pins to be severed at a severing position without fail even with the belts of various pitches of connecting pieces.
To this end, according to one aspect of the invention, there is provided a method of attaching a connecting piece for connecting two members to each other, the connecting pieces being severed one by one by an attaching device from a continuous belt or group of connecting pieces which is formed integrally from a plastic and in which a plurality of connecting pieces, each having a filament portion, a head portion connected to one end of the filament portion and a cross-bar portion connected to the other end of the filament section, are connected in parallel relationship by means of a connecting rod located outside said cross-bars and perpendicular to the filament portions, the severed connecting piece being attached by the attaching device to connect the two members to each other, characterized in that the connecting piece in the severing position is biased continuously and resiliently in the direction of feed of the belt of connecting pieces, over at least a period until the severed connecting piece is located upon abutment with a stopper of severing position of the attaching device.
According to another aspect of the invention, there is provided a device for attaching a connecting piece for connecting two members to each other, the device being adapted to severe said connecting piece one by one from a belt or group of connecting pieces which is formed integrally from a plastic and in which a plurality of connecting pieces, each having a filament portion, a head portion connected to one end of said filament portion and a cross-bar portion connected to the other end of the filament section, are connected in parallel relationship by means of a connecting rod located outside the cross-bar portion and perpendicular to the filament portion, the device being further adapted to attach the severed piece to said members, characterized by comprising: a stopper member disposed at a severing position at which said connecting pieces are severed one by one; and a connecting piece driving member which is adapted to bias the connecting pieces in the severing position continuously and resiliently in the direction of feed of said belt, over at least a period until the connecting piece to be severed is located upon abutment with the stopper member.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view showing the inner structure of an attaching device in accordance with the invention;
FIG. 2 is a perspective view of a part of the attaching device of the invention, showing particularly a feed mechanism; and
FIGS. 3 and 4 are front elevational views of different examples of the feed mechanism.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to the attaching device for attaching the connecting piece, the attaching device has a main body 4 having a pistol-like form. The main body 4 is split into two halves along a thickness-wise bisector line. After mounting various mechanism in one of the halves as illustrated, the other half part is coupled to the first half to cover the mechanisms mounted in the latter.
The main body 4 has a grip 4a at the front part of which pivotally mounted is a lever 5 for swinging movement in the direction of an arrow A-B around a pivot shaft 5a. An operation link 6 adapted to be swung around a pivot shaft 6a together with the lever 5.
A spring retainer 7 is fitted to the rear wall 4b of the grip 4a of the main body 4, while a lever resetting member 8 abuts against the portion of the operation link 6 below the pivot shaft 6a. A compression coiled spring 9 is disposed to act between the spring retainer 7 and the lever resetting member 8 to normally bias the operation link 6 and the lever 5 in the direction of arrow A.
A guide groove 10 for slidably receiving and guiding a rod driving member 11 is formed in the upper part of the main body 4 to extend in the direction of arrow C-D. The rod driving member 11 is operatively connected to the operation link 6 through an intermediate link 12. The arrangement is such that the rod driving member 11 slides in the guide groove 10 in the direction of arrow C-D as the lever 5 is swung in the direction of arrow A-B.
A driver 13 for driving the end surface of the cross-bar portion 1b of the connecting piece is attached to the rod driving member 11. A guide needle 14 detachably secured to the front end portion of the main body 4 extends along the extension of the axis of the driver 13. The guide needle 14 is provided with a groove 14a through which the filament portion 1c of the connecting piece moves. A feed groove 15 for a belt or group of connecting pieces is formed in the portion of the main body 4 behind the guide needle 14, so as to extend substantially at a right angle to the axis of the guide needle 14.
As will be understood from FIG. 2, the corner of the feed groove 15 closer to the guide needle 14 is provided with a cutter 16 which is adapted to cut the belt of connecting pieces at a portion of the latter between the cross-bar portion 1b and a connecting portion 1d when the cross-bar portion 1b of connecting piece 1 is pressed by the driver 13. The position at which the connecting piece or tag pin 1 is severed from the belt 3 is so determined as to make the line interconnecting the axes of the guide needle 14 and the driver 13 coincide with the axes of the cross-bar portion 1b of the connecting piece 1 to be severed. To correctly locate the connecting piece at this position, a stopper projection 17 is formed to project from the main body 4 so as to receive the cross-bar portion 1b.
Also in FIG. 2 showing a feed mechanism 18 for feeding the connecting piece 1 to the severing position, a support member 19 is fixedly mounted in the main body 4 to which fixed is the rear end portion of a member 20 having a hooked front end 20a. The member 20 is provided for preventing the reverse movement of the belt 3 of the connecting pieces and is constituted by a leaf spring or made of a plastic having a good resiliency. The hooked front end portion 20a of the member 20 confronts the front side of the feed groove 15 so as to press the connecting portion 1d of the connecting piece 1.
Also, a connecting piece driving member 21 having the same shape as the member 20 is positioned at the outside of the member 20 for preventing the reversing of the belt 3. As is the case with the member 20, this connecting piece driving member 21 is constituted by a leaf spring or made of a plastic having a good resiliency. The front end portion 21a of the connecting piece drive member 21 confronts the front side of the feed groove 15 so as to press the connecting portion 1d of the connecting piece 1d. The connecting piece driving member 21 thus arranged is connected at its rear end to a movable feed member 22 which is adapted to be moved in the directions of arrows E-F being guided by a groove 23 of the main body 4. Normally, the movable feed member 22 is biased in the direction of arrow F by means of a coiled spring 24.
A tapered cam surface 22a is formed on the lower side of the movable feed member 22. Also, another tapered cam surface 11a is formed on the front part of the rod driving member opposing to the tapered cam surface 22a. The size and shape of the tapered cam surface are determined preferably such that these tapered cam surfaces 11a, 22a come to cooperate with each other to drive the movable feeding member 22 in the direction of arrow E at such a moment when the driver 13 drives the cross-bar portion 1b of the connecting member in the severing position and the connecting portion 1d is contacted by the cutter 16, and that the stroke of the movement of the movable member 22 is at least greater than the conceivable maximum pitch P of the connecting pieces.
Also, as will be seen from FIG. 2, a semicircular actuating member 25 is disposed to oppose to the front surface of the vertical portion of the member 20 for preventing the reversing of the belt. As the lever 5 of the actuating member 25 outside of the main body 4 is swung in the direction of arrow G, the member 20 for preventing the reversing moves in the direction of arrow D thereby to disengage the front end portions 20a, 21a of the members 20, 21 from the connecting portion 1d of the connecting piece belt 3.
Hereinafter, an explanation will be made as to how the connecting piece is attached to an object by the attaching device of the invention having the described construction.
First of all, the belt 3 of connecting pieces 1 is inserted into the feed groove 15 to bring the cross-bar 1b of a connecting piece 1 to be severed into abutment with the stopper projection 17. Then, after inserting the guide needle 14 into a plurality of objects 26,27 positioned in a superposed manner, as shown in FIG. 2. Then, the lever 5 is swung in the direction of arrow B so that the projection 5b of the lever 5 presses the lower end of the operation link 6 in the direction of arrow B. Consequently, the operation link 6 rotates around the pivot shaft 6a in the direction of arrow B. By so doing, the rod driving member 11 is moved in the direction of arrow C through the medium of the intermediate link 12. The driver 13 which is driven by the rod driving member 11 and moves in the same direction as the latter to come into contact with the cross-bar portion 1b of the connecting piece 1 to be severed, thereby to drive the connecting portion 1d of the same against the cutter 16.
At this moment, the tapered cam surface 11a of the rod driving member 11 engages the tapered cam surface 22a to lift the movable feed member 22 in the direction of arrow E.
As the driver 13 is moved further in the direction of arrow C from this position, the connecting portion 1d of the connecting piece 1 to be severed is cut by the cutter 16 and the cross-bar portion 1d is driven into the guide needle 14 to come out of the side of the objects 26,27 opposite to the attaching device. The cross-bar portion 1d of the severed connecting piece 1 is then disengaged from the guide needle 14 as shown by imaginary line in FIG. 2. Meanwhile, the connecting piece driving member 21 moves in the direction of arrow E over the connecting portion 1d of the connecting piece 1 which is still in the severing position, while the member 20 holds the connecting piece band 3 so that the latter may not move in the reverse direction, i.e., in the direction of arrow E.
After securing the connecting piece 1 to the objects 26, 27, the lever 5 is reset in the direction of arrow A of FIG. 1 by the action of the compressed coiled spring 9. Accordingly, the driver 13 and the rod driving member 11 are moved in the direction of arrow D.
Therefore, the movable feeding member 22 which has been raised in the direction of arrow E by the tapered cam surface 11a of the movable rod member 11 is gradually moved in the direction of arrow F by the action of the compressed coiled spring 24. As a result, the connecting piece driving member 21 presses the connecting portion 1d of the connecting piece 1 which is still out of the severing position, in the direction of arrow F. In this state, only the connecting portion 1d of the severed connecting piece 1 is left in the severing position, so that the connecting piece belt 3 as a whole can move in the direction of arrow F without encountering the interference of the stopper projection 17. Then, the next connecting piece 1 to be severed is stopped by the stopper projection so as to be located by the latter, and the connecting piece driving member 21 and the movable feeding member 22 hold their positions in a suspended state.
When the connecting member 1 is fed in the direction of arrow F by the connecting piece driving member 21 to bring the cross-bar portion 1b into abutment with the stopper projection 17, the cross-bar portion 1b may be inclined due to the pressure exerted in the direction of arrow F. Such an inclination, however, can be avoided by providing another stopper projection 17a on the other half (not shown) of the main body 4 as shown by an imaginary line, so that the cross-bar portion 1d can always be held on the common axis of the guiding needle 14 and the driver 13.
On the other hand, following the movement of the connecting piece belt 3 in the direction of arrow F, the member 20 for preventing the reversing of the belt 3 is once kicked outwardly by the connecting portion 1d moving in the direction of arrow F and is then reset to press the connecting portion 1d.
Since the connecting piece belt 3 is fed in the described manner, connecting pieces 1 can be advanced by a distance which is exactly the same as those of the pitch of the connecting pieces, even when the stroke of the connecting piece driving member 21 in the direction of arrow E is selected to be one to several times as large as the pitch of connecting pieces 1 which are still out of the severing position. More specifically, provided that the pitch of connecting pieces 1 in a connecting piece belt 3 is 2 mm, it is possible to exactly locate a next connecting piece to be severed in the severing position even when the pitch is fluctuated within the region of between 1 mm and 4 mm. It is, therefore, possible to sever the connecting pieces one by one even with a connecting piece belt of a random pitch of connecting pieces, or with different connecting piece belts having different pitches of connecting pieces.
The connecting piece driving member 21A and the member 20A for preventing the reversing of the connecting piece belt may be formed to extend in the direction of arrow C as shown in FIG. 3. In this case, a support member 19A for the member 20A is attached to the main body 4A for free movement in the direction of arrows C-D. Also, the movable feeding member 22A is fitted to the support member 19A for free movement in the directions of arrow E-F, while the movable feeding member 22A is biased in the direction of arrow F by a compressed coiled spring 24A. Further, the movable feeding member 22A and the rod driving member 11A are provided with tapered cam surfaces such that the movement of the rod driving member 11A in the direction of arrow C causes a movement of the movable feeding member 22A, i.e., connecting piece driving member 21A, in the direction of arrow E thereby to feed the connecting piece belt 3 in the direction of arrow F by the force of the compressed coiled spring 24A. For disengaging the connecting piece driving member 21A and the member 20A for preventing the reversing of the connecting piece belt 3, the support member 19A is simply displaced in the direction of arrow D.
FIG. 4 shows another form of feed mechanism for feeding the belt 3 of connecting piece. In this mechanism, the connecting piece driving member 21B and the member 20B for preventing the reversing of the belt 3 are formed integrally with each other to present as a whole a substantially U-shaped form. The portion of this unitary body constituting the member 20B for preventing the reversing is fixed by means of a support member 19B. The support member 19B is attached to the main body 4B for free movement in the directions of arrow H-J. For disengaging the connecting piece driving member 21B and the member 20B for preventing the reversing, the support member 19B is moved in the direction of arrow H, while, for feeding the connecting piece belt 3 in the direction of arrow F, a cam groove 28B as illustrated is formed in the rod driving member 11A so as to receive one end 31B of a link 30B which is pivotally supported by the main body 4B at a pivot point 29B. The other end of the link 30B is made to contact the inside of the connecting piece driving member 21B.
In operation, the connecting piece driving member 21B is moved to the position of imaginary line as the rod driving member 11B is moved in the direction of arrow C. Also, the link 30B is returned from the position of full line to the position of broken line as the rod driving member 11B is moved in the direction of arrow D.
As a result, the freed connecting piece driving member 21B drives the connecting piece belt 3 in the direction of arrow F, kicking the member 20B for preventing reversing, due to its resiliency. This feeding mechanism is advantageous in that the number of parts is considerably decreased.
As has been described, according to the invention, it is possible to feed a connecting piece to be severed, from a position out of the severing position correctly to the severing position, by suitably hitching and pressing the connecting piece which is still out of the severing position.
Consequently, the attaching method and device of the invention make it possible to handle a connecting piece belt of an irregular pitch of connecting pieces and connecting piece belts having different pitches of connecting pieces. | A method of and apparatus for attaching a connecting piece to objects to connect these objects to each other. The connecting pieces each having a filament portion, a head portion attached to one end of the filament portion and a cross-bar portion attached to the other end, are successively severed one by one by the attaching device from a continuous belt of connecting pieces formed integrally from a plastic and having a connecting rod to which the connecting pieces arranged in side-by-side relation are connected through respective connecting portions, and are then attached to the objects to connect them to each other. The improvement resides in a technic which ensures to correctly position the connecting piece to be severed to the severing position even when the connecting pieces in the connecting piece belt are disposed at an irregular pitch. This can be achieved by continuously pressing the connecting piece to be severed in the direction of feed of the belt until the connecting piece to be severed is stopped and located by a stopper member disposed in the severing position. |
BACKGROUND OF THE INVENTION
The present invention relates to concrete paving.
The technology for providing concrete paving that has surface features has become an important field of endeavor with the advent of Americans with Disabilities Act (ADA) current guidelines requirement for detectable warnings on walking surfaces. These detectable warnings must be a grid of raised truncated domes with a diameter of 23 mm (0.9 in) at the base and 10 mm (0.4 in) at the top, a height of 5 mm (0.2 in) and a center-to-center spacing between nearest neighbors of 60 mm (2.35 in).
A number of different technologies have evolved to create the detectable warnings. First there is a polymer molded product that is about 5 mm (0.1875 in) thick and is provided in the form of tiles having flanges that extend downwardly by 3.5 cm (1.375 in). To install this product, the flanges are pressed into wet concrete. This material is light, and therefore easy to bring to the worksite. It may form a strong bond with the concrete that it is applied onto. Moreover, the fact that it is applied onto wet concrete is a great advantage, as it can be applied at the same time as the concrete is poured, unlike some other methods that are described below. The general term for this type of product is a “wet set” plastic tile.
A number of other surface feature-bearing elements exist, including precast concrete blocks, on the order of 5 cm (2 in) thick, brick pavers, glue down plastic elements, glue down rubber mat and hot applied mat. Unfortunately, for each one of these options, the installer must first pour a concrete substrate, wait 28 days for the concrete to thoroughly set, and then return to apply the surface feature bearing elements. This has been heretofore necessary for any product that had a thickness of more than a few millimeters, as the surface bearing element would otherwise protrude upwardly above the surrounding surface. Precast concrete blocks have had the particular problem that they are so heavy that if set into wet concrete such a block would press down so heavily as to push the wet concrete up around the sides of the concrete block. Any glue down product must be adhered to a finished substrate in order to gain a strong adhesion. Moreover, brick pavers must be laid on an even finished surface. Because they are supported by a substrate that is already solid at the time of installation, all of these products tend to have substantially planar bottom surfaces.
In a separate sequence of developments, prestressed concrete has been available for many years, with improvements gradually being made to the production process and the resultant product. A relatively recent advancement is described in U.S. Patent Application Publication 2002/0059768 (“the application”), which is incorporated by reference as if fully set forth herein. The application describes a method for producing a thin, lightweight prestressed concrete panel by balancing the tendons about a center plane of the panel. There appears to be no suggestion in the application that the panels thereby produced could be beneficially used as paving tiles.
Moreover, at first assessment, it would seem to many of those familiar with the technology of concrete installations that the use of this type of panel for paving would be limited to applications in which a substrate of cured concrete first must be provided. This appears to be how the previously available concrete blocks and all of the adhered paving elements have been installed. Moreover, the added expense of using prestressed concrete for applications in which there is not a structural requirement to do so, would not appear practical.
SUMMARY OF THE INVENTION
In a first separate aspect, the present invention is a method of providing a paved area having a predetermined set of surface features. The method begins with the pouring of wet concrete into a predetermined area. Then a predetermined thickness of the wet concrete is removed in a predetermined portion of the predetermined area, thereby creating a lower, upwardly facing surface in the predetermined portion. At this point, a paving tile having the predetermined set of surface features is placed on the lower, upwardly facing surface. Finally, the wet concrete underneath and about the paving tile is permitted to cure.
In a second separate aspect, the present invention is a method of removing a predetermined area and depth of formable material from an expanse of the formable material having a top surface. The method makes use of a shovel guide tool, comprising at least one shovel guide having a top surface; a depth indicator having a bottom surface at a height above the shovel guide substantially equal to the predetermined depth; and an area indicator, indicating an area equal to the predetermined area. The shovel guide tool is pushed into the formable material until the bottom surface of the depth indicator is level with the formable material top surface, thereby pushing the shovel guide top surface to the predetermined depth. Then a shovel is pushed into the deformable material until it encounters the top surface of the at least one shovel guide and it is run along the top surface until it is at least partially filled with deformable material. The shovel is emptied at a location away from the shovel guide tool. The shoveling process is continued until the area indicated by the area indicator is cleared of formable material down to the top surface of the at least one shovel guide.
In a third separate aspect, the present invention is a structure that includes a layer of wet concrete. A concrete tile having side surfaces and having a top surface bearing surface features is supported by the wet concrete. The structure also includes wet concrete that abuts the side surfaces of the concrete tile.
In a fourth separate aspect, the present invention is a structure that a prestressed concrete tile having a bottom major surface, side edges and a top major surface. A unitary body of concrete supports the bottom major surface of the concrete tile and contacts the side edges of the concrete tile. In addition, the bottom major surface and side edges of the concrete tile are adhered to the unitary body of concrete.
The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the preferred embodiment(s), taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a shovel guide tool according to a preferred embodiment of the present invention.
FIG. 2 is a side of the shovel guide tool of FIG. 1 being positioned above an expanse of formable material, according to a step of a preferred method of the present invention.
FIG. 3 is a side view of the elements shown in FIG. 2 with the shovel guide tool pressed into the formable material, according to a further step of a preferred method of the present invention.
FIG. 4 is a side view of the elements of FIG. 3 , also showing a shovel being moved along the shovel guide tool, according to a further step of the preferred method of the present invention.
FIG. 5 is a side view of a finished concrete installation, which may be a result of the method partially shown in FIGS. 2 , 3 and 4 and is in itself a preferred embodiment of the present invention.
FIG. 6 is a greatly enlarged partial side view of the finished concrete installation of FIG. 5 .
FIG. 7 is a partial side view of the finished concrete installation of FIG. 5 , which is enlarged relative to FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A first preferred method of the present invention is a method of removing a predetermined area and depth of wet concrete ( FIG. 2 ), or other formable material, from an expanse of the wet concrete 10 . This is most typically done for the purpose of setting a tile of matching area and thickness (see below). This method makes use of a shovel guide tool 12 , comprising a set of shovel guides 14 , in the form of ribs. A depth and area indicator 16 , is in the form of a rectangular frame having handles 17 . Indicator 16 has a bottom surface that is at a height 18 ( FIG. 2 ) above the tops of shovel guides 14 that is substantially equal to the predetermined depth. The shovel guide tool 12 is pushed into the wet concrete 10 until the bottom surface of the depth indicator 16 is level with the top surface of the wet concrete 10 , thereby pushing the top surface of the shovel guides 14 to the predetermined depth.
A shovel 20 is pushed into the wet concrete until it encounters the top surfaces of the shovel guides 14 and is run along these top surfaces until it is at least partially filled with wet concrete 10 . The shovel 20 is emptied at a location away from the shovel guide tool 12 . The shoveling process is continued until the area indicated by the area indicator 16 is cleared of wet concrete 10 down to the top surfaces of the shovel guides 14 .
At this point a depression of predetermined depth and area has been created in the wet concrete. In a preferred embodiment guide tool 12 is constructed to create a depression of exactly the right area and depth to accommodate a concrete tile 30 . Tile 30 may have a width of about 0.6 meters (approximately 2 feet) and may be either about 0.6, 0.75 or 0.9 meters (approximately 2, 2.5, or 3 feet) long. In a preferred method a 3 mm (⅛ in) coat of mortar is applied to the bottom of tile 30 immediately prior to installation. Tile 30 is then placed into the depression created and concrete 10 is compacted and finished about it. Additional wet concrete 10 may be added to help retain a set of wedge sections 32 of tile 30 .
The above described process creates a structure in which tile 30 is supported from the bottom and contacted on the sides by wet concrete 10 . After concrete 10 has cured, this structure is set, with tile 30 being similarly supported and contacted by cured concrete. In a preferred embodiment, tile 30 defines pores 34 ( FIG. 6 ), some of which are at least partially filled with concrete 10 . Also, the bottom surface of tile 30 is indented with a set of furrows 36 ( FIG. 7 ) that facilitate the formation of an interlocked bond with the underlying concret 10 . The structure created, in which tile 30 is supported and held in place by surrounding concrete 10 is of particular strength. Moreover, it is very resilient to compression and shear, as may be encountered by a concrete installation when trucks either pass by the installation or pass at least partially over the installation.
Tile 30 may have surface features, such as a grid of truncated domes 40 . As noted in the background section, domes 40 serve as detectable warnings, and are mandated by the ADA guidelines for various installations including curb cuts, train station platforms, hazardous vehicular crossings and reflecting pool edges. In some instances a grid having a width of 0.9 meter (@ 3 ft) is required, instead of the standard 0.6 meters (@ 2 ft). Under the current guidelines, domes 40 must have a diameter of 23 mm (0.9 in) at the top and 10 mm (0.4 in) at the top, a height of 5 mm (0.2 in) and a center-to-center spacing of 60 mm (2.35 in) between nearest neighbors. Tiles, similar to tile 30 , may be used for other purposes. Among these are adding strength to a concrete paved area; adding a colorful design to an area; adding artistic surface protrusions; and having a set of surface features or a surface shape that facilitates water drainage.
In one preferred embodiment, tile 30 is of a make generally described in U.S. Patent Application Publication 2002/0059768, which has been incorporated by reference. In an alternative preferred embodiment a concrete paving tile of a differing construction is used. In one preferred embodiment a set of tendons are added that place the bottom half of paving tile 30 under more compressive stress than the top half. As paving tile 30 is supported by concrete material 10 , this unequal compressive stress is, in some instances, beneficial.
In many types of installations it is beneficial to have a thicker layer of concrete material underneath and supporting tile 30 than elsewhere. In a curb cut installation, wet concrete 10 is formed to a sloping grade prior to the installation of tile 10 , rather than being level.
In a preferred embodiment, tiles 30 are cast in 0.6 m (2 ft) by 2.4 m (8 ft) by 2.22 cm (0.875 in) sections and are cut in the shop into 0.6 m by 0.6 m, 0.75 m or 0.9 m (2 ft, 2.5 ft or 3 ft) sections. In addition, because tiles 30 are substantially uniform in cross section they may be cut at the job site to accommodate local features. For example, a vault box or a bollard may be accommodated by cutting the tile 30 into an accommodating shape. This task may be a difficult or impossible if using tiles that cannot be modified from the standard, factory provided shapes. Such tiles appear to include the wet set plastic tiles and the concrete blocks described in the background section.
The terms and expressions that have been employed in the foregoing specification are used as terms of description and not of limitation. In particular, the term concrete, wherever it is used in this application, refers to any cementitious material generally used in construction, for example a mixture of cement and sand, commonly known as “mortar” is considered to be “concrete” in this application. There is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow. | A method of providing a paved area having a predetermined set of surface features. The method begins with the pouring of wet concrete into a predetermined area. Then a predetermined thickness of the wet concrete is removed in a predetermined portion of the predetermined area, thereby creating a lower, upwardly facing surface in the predetermined portion. At this point, a paving tile having the predetermined set of surface features is placed on the lower, upwardly facing surface. Finally, the wet concrete underneath and about the paving tile is permitted to cure. |
FIELD OF THE INVENTION
The present invention relates to a safety box apparatus, and more particularly, to an electronic key box.
BACKGROUND OF THE INVENTION
Conventional safety boxes are mostly locked by mechanical means, and can only be opened by a key that is carried by a user. Further, for electronic safety boxes locked by electronic passwords, it is necessary that a user remembers a password set by oneself so that a safety box can be opened by pressing number keys.
SUMMARY OF THE INVENTION
It is an objective of the present invention to provide an electronic key box, which offers dual functions of electronic password and mechanical locks to optimize utilization flexibilities.
It is another objective of the present invention to provide an electronic key box, which covers a keyhole of a mechanical lock when the mechanical lock is not in use to offer both security and esthetic effects.
To achieve the objectives above, the present invention provides a key box comprising: a body; a cover, pivotally connected with the body to render an open state and a closed state; and a panel set, embedded on the cover, comprising a keypad module and a lock module. Wherein, by manipulating either the keypad module or the lock module, the open state and the closed state can be switched.
The key box of the present invention further comprises a switch module provided at an inner side of the cover. The switch module comprises: a plate; a sliding piece, slidably provided on the plate; a pair of rotating pieces, rotatably provided on the plate; and an solenoid switch, comprising a blocking section for blocking against the sliding piece under the closed state and being disengaged from the sliding piece under the open state.
According to the key box of the present invention, the sliding piece comprises a push piece for coordinating with the keypad module for switching the key box between the open state and the closed state.
According to the key box of the present invention, the panel set comprises an opening comprising at two sides thereof a pair of substantially parallel guiding tracks, and a button accommodated in the opening and is restrained to slide along a predetermined direction according to the guiding tracks.
According to the key box of the present invention, the plate further comprises a positioning piece for positioning the blocking section.
According to the key box of the present invention, wherein the positioning piece comprises non-magnetizing material.
According to the key box of the present invention, another sliding piece is further comprised and is slidably provided on the sliding piece.
According to the key box of the present invention, the another sliding piece comprises a push piece for coordinating with the lock module for switching the key box between the open state and the closed state.
According to the key box of the present invention, a concealing cover is further comprised for movably covering the lock module.
According to the key box of the present invention, a circuit board is further comprised near the keypad module and is electrically connected with the keypad module and the solenoid switch.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:
FIG. 1 is an elevational view of a key box according to a preferred embodiment of the present invention.
FIG. 2 is a front view of the key box in FIG. 1 .
FIG. 3 is a side view of the key box in FIG. 1 .
FIG. 4 is a front view of a panel set.
FIG. 5 is a rear view of a panel set.
FIG. 6 is an elevational view of a switch module.
FIG. 7 is a front view of a switch module.
FIG. 8 is a partial enlarged view of a switch module.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 , 2 and 3 respectively show an elevational view, a front view and a side view of an electronic key box according to a preferred embodiment of the present invention. Referring to FIGS. 1 to 3 , the electronic key box according to a preferred embodiment of the present invention comprises a hollow body 1 , a cover 2 , a pivot 3 , a panel set 4 and a handle 5 . The cover 2 is pivotally connected to the body 1 via the pivot 3 , so that the cover 2 is allowed to become a closed state or an open state relative to the body 1 . Under a closed state, the cover 2 is closely engaged with the body 1 to prevent a risk of undesired peeping or undesired obtaining a content of the box, and so a shape of the cover 2 is necessarily formed to match a geometric shape of the body 1 . Further, the cover 2 and the body 1 , being rigid and endurable, are generally formed by a strong material such as metal or plastic steel.
Referring to FIGS. 1 to 3 , the handle 5 is fixed to the body 1 , and allows grasping of a user so that the user may move or carry the key box when the cover 2 is closed relative the body 1 . Further, the panel set 4 , embedded on the cover 2 at one side of the cover 2 , comprises a keypad and a lock for allowing a user to open or close the key box. The keypad and the lock shall be described below.
FIGS. 4 and 5 respectively show a front view and a rear view of the panel set 4 . As shown, the panel set 4 comprises a keypad module 40 , a lock module 41 and a button 44 . The key module 40 comprises numeral keys of 0 to 9, and symbol keys of “*” and “#”, and is electrically connected to a circuit board 43 . Preferably, the circuit board 43 is provided closely to a rear side of the keypad module 40 , such that the circuit board 43 is facilitated to receive a corresponding electronic signal when a user presses the numeral keys or symbol keys of the keypad module 40 . The lock module 41 comprises a hook section 47 to be described shortly. The panel set 4 further comprises an opening 45 , and a pair of guiding tracks 46 A and 46 B (as shown in FIG. 5 ) in the inner side of the opening 45 to accommodate the button 44 therein, such that the button 44 is slidable according to the restraints of the guiding tracks 46 A and 46 B along a predetermined direction.
FIGS. 6 and 7 respectively show an elevational view and a front view of a switch module. The switch module is provided at a rear side of the cover 2 , and is a mechanical structure for coordinating with the keypad module 40 and the lock module 41 of the panel set 4 . FIG. 8 shows a partial enlarged view depicting details of the switch module. Referring to FIGS. 6 to 8 , all components of the switch module are provided on a plate 60 , and the switch module comprises a button sliding piece 62 , a lock sliding piece 64 , a pair of rotating pieces 66 A and 66 B, and a solenoid switch 68 .
The rotating pieces 66 A and 66 B are spaced with a fixed distance in between, and are respectively rotatably provided on the plate 60 via rivets 661 A/ 662 A and 661 B/ 662 B. The rotating pieces 66 A and 66 B respectively comprise arched openings 663 A and 663 B. When the rotating pieces 66 A and 66 B respectively rotate around the rivets 661 A and 661 B as axes thereof, the rotating pieces 66 A and 66 B are enabled to rotate at closed positions or open positions since the rivets 662 A and 662 B respectively coordinate with the arched openings 663 A and 663 B. Referring to FIG. 8 , the rotating pieces 66 A and 66 B are under a closed state. The rotating pieces 66 A and 66 B are tied closer by means of a spring 70 . When no external force is exerted on the key box, the rotating pieces 66 A and 66 B are rest on the closed positions by means of the spring 70 coordinating with the rivets 662 A and 662 B.
The button sliding piece 62 may be slidably provided on the plate 60 , and the lock sliding piece 64 may be slidably provided on the button sliding piece 62 . In other words, the lock sliding piece 64 is superimposed on the button sliding piece 62 , and both are provided over the plate 60 via the rivet 644 . The lock sliding piece 64 and the button sliding piece 62 correspond to respective openings. As shown in FIG. 8 , the rivet 644 coordinates with the opening 645 of the lock sliding piece 64 so that the lock sliding piece 64 is allowed to slide at the closed position or the open position. Similarly, the button sliding piece 62 also corresponds to an opening (not shown in the drawing) and coordinates with the rivet 644 so that the button sliding piece 62 is allowed to slide at the closed position or the open position. According to an embodiment of the present invention, the button sliding piece 62 actuates the lock sliding piece 64 to slide simultaneously. However, the button sliding piece 62 is not actuated to slide by the sliding of the lock sliding piece 64 .
Referring to FIG. 8 , the lock sliding piece 64 comprises strip sections 642 A and 642 B at two sides thereof. The strip sections 642 A and 642 B respectively butt against projecting portion 664 A of the rotating piece 66 A and the projecting portion 664 B of the rotating piece 66 B, and the strip section 642 B comprises a breach 643 at an end near the solenoid switch 68 . Further, the lock sliding piece 64 comprises a push piece 641 vertically extended from its one end near the rotating pieces 66 A and 66 B. When a user opens the box with a key, the hook section 47 of the lock module 41 thrusts force upon the push piece 641 , such that the lock sliding piece 64 respectively applies force on the projecting portion 664 A of the rotating plate 66 A and the projecting portion 664 B of the rotating plate 66 B. Accordingly, the rotating pieces 66 A and 66 B are rotated to deform and extend the spring 70 to open the box. When a user closes the box with a key, the hook section 47 of the lock module 41 is disengaged from the push piece 641 . Due to a restoring force of the spring 70 , the lock sliding piece 64 is pushed away from rotating pieces 66 A and 66 B by the projecting portion 664 A of the rotating plate 66 A and the projecting portion 664 B of the rotating plate 66 B and back to the closed position.
The button sliding piece 62 comprises projecting portions 622 A and 662 B at two sides thereof for respectively butting against an end of the rotating pieces 66 A and 66 B. The button sliding piece 62 comprises a push piece 621 vertically extended from its one end near the rotating pieces 66 A and 66 B. When a user opens the box by pressing the button 44 , the button 44 thrusts force upon the push piece 621 , such that the button sliding piece 62 respectively applies force on one end of the rotating pieces 66 A and 66 B. Accordingly, the rotating pieces 66 A and 66 B are rotated to deform and extend the spring 70 to open the box. When the button 44 is not pressed by a user, due to a restoring force of the spring 70 , the button sliding piece 62 is pushed away from the rotating pieces 66 A and 66 B by the rotating pieces 66 A and 66 B and back to the closed position. According to the present invention, the button sliding piece 62 further comprises a long strip section 623 at one side near the solenoid switch 68 . A spring 72 is provided between the long strip section 623 and a projecting portion 601 of the plate 60 to coordinate with the spring 70 , so as to ensure that the button sliding piece 62 restores from the open position back to the closed position.
The solenoid switch 68 comprises a blocking section 681 extended from one side of the solenoid switch 68 that is near the button sliding piece 62 . Further, the solenoid switch 68 is electrically connected to the circuit board 43 and is controlled by circuits on the circuit board 43 . When a password entered by a user is correct, the solenoid switch 43 withdraws the blocking section 681 inwards via controls of the circuits on the circuit board 43 . When the key box is under the closed state, the blocking section 681 of the solenoid switch 68 blocks against the long strip section 623 of the button sliding piece 62 . At this point, the button sliding piece 62 remains immobile even when the button 44 is pressed by a user. Only when a password entered by a user is correct, the solenoid switch 68 shall withdraw the blocking section 681 inwards. At this point, by pressing the button 44 to apply force on the push piece 621 , the button sliding piece 62 is enabled to slide via the projecting portions 622 A and 622 B to respectively apply force at one end of the rotating pieces 66 A and 66 B. Accordingly, the rotating pieces 66 A and 66 B are rotated to deform and extend the spring 70 to open the box.
To coordinate with the blocking section 681 , the plate 60 comprises a positioning piece 682 for positioning. Further, to prevent a drawback that the blocking section 681 may fail to restore to its original position when electricity is cut off due to magnetization after the blocking section 681 of the solenoid switch 68 was electrically connected, the positioning piece 682 would be made of non-magnetizing material or covered with non-magnetizing material. Preferably, the positioning piece 682 may be made of plastic, or a plastic piece is enclosed around the positioning piece 682 to prevent the issue of position restoring failure of the blocking section 681 .
With the lock module 41 of the key box of the present invention, a user may still open the key box with a key as an alternative solution in the event that a user forgets the password and cannot open the key box through the keypad module 40 . To achieve the alternative solution, the strip section 642 B of the lock sliding piece 64 comprises the breach 643 , which has a sufficient width to avoid any contact with the blocking section 681 of the solenoid switch 68 . Since the opening of the key box with the lock module 41 is rather an alternative solution which may not be utilized most of the time, a concealing cover 42 is provided to cover the lock module 41 for security and esthetic considerations when the lock module 41 is not in use. When a user needs to open the lock module 41 , the concealing cover 42 may be moved by sliding to reveal the keyhole of the lock module 41 to allow a user to insert the key.
Therefore, the key box of the present invention provides dual functions of an electronic lock and a mechanical lock to optimize utilization flexibilities. Further, when the mechanical lock is not in use, the keyhole of the mechanical lock is covered to further offer security and esthetic effects.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not to be limited to the above embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. | According to the present invention, a key box is provided to include: a body; a cover, pivotally connected with the body to render an open state and a closed state; and a panel set, embedded on the cover, comprising a keypad module and a lock module. Wherein, by manipulating either the keypad module or the lock module, the open state and the closed state can be switched. |
CLAIM OF PRIORITY
This application is a continuation of and claims the benefit of priority to U.S. application Ser. No. 13/166,080, filed Jun. 22, 2011, incorporated herein by reference.
TECHNICAL FIELD
The present invention relates generally to improvements in downhole drilling equipment and more particularly pertains to a new improved housing, mandrel and bearing assembly for transmitting power from a downhole drilling motor output to a drill bit.
BACKGROUND
Downhole drilling motors have been used for many years in the drilling of oil and gas wells and other wells. In the usual mode of operation, the rotational power output shaft of the motor and the drill bit will rotate with respect to the housing of the motor. The housing, in turn, is connected to a conventional drill string composed of drill collars and sections of drill pipe. This drill string extends to the surface. Drilling fluid is pumped down through the drill string to the bottom of the hole and back up the annulus between the drill string and the wall of the bore hole. The drilling fluid cools the drill bit and removes the cuttings resulting from the drilling operation. In the instances where the downhole drilling motor is a hydraulic powered type, such as a positive displacement type motor, the drilling fluid also supplies the hydraulic power to operate the motor. See FIG. 1 .
Virtually all downhole drilling motors have three basic components:
1. Motor section
2. Vertical thrust bearings
3. Radial bearings
The bearings can be placed in a separate package or unit at the motor section and thus can be used on any type of motor (i.e., turbodrills, positive displacement motors, etc.).
There are two basic types of downhole drilling motors:
1. Turbodrills
2. Positive displacement motors.
Turbodrills utilize the momentum change of drilling fluid (i.e., mud) passing through curved turbine blades to provide power to turn the bit. Turbodrills turn at speeds of 600 to 3,000 rpm. Positive displacement motors have fixed volumetric displacement and their speed is directly proportional to the flow rate of the hydraulic power fluid.
There are two basic types of positive displacement motors in use:
1. Moineau motors have a helical rotor within the cavity of a stator which is connected to the housing of the motor. As the drilling fluid is pumped down through the motor, the fluid rotates the rotor.
2. Vane motors have large volumetric displacement and therefore deliver higher torques at lower speeds.
Thrust bearing failure in downhole motors is a problem because of high dynamic loads produced by the action of the bits and by drill string vibrations. One major oil company placed a recorder at the hole bottom and found that dynamic loads were often 50% higher than the applied bit weight. It was found on occasion that the bit bounced off the bottom and produced loads in excess of 120,000 pounds when drilling at an applied bit weight of 40,000 pounds. See discussion in U.S. Pat. No. 4,246,976, incorporated by reference. These high loads can cause rapid failure of the thrust bearings and bearing mandrels; consequently, these bearings must be greatly over-designed to operate in the hostile downhole environment.
At least three types of thrust bearings have been used in downhole drilling motors:
1. Rubber friction bearings
2. Ball or roller bearings
3. PDC Diamond Bearings.
Radial bearings are required between the bearing housing and the rotating mandrel transmitting power from the motor power output to the bit. Radial bearings are usually subjected to lower loads than the thrust bearings and therefore have much longer life. The basic types of radial bearings used in downhole motors are:
1. Marine bearings
2. Roller or ball bearings
3. Metal to metal carbide bearings.
Most motors contain metal to metal radial bearings. These bearings are frequently lubricated by circulating mud through them. However, some bearing systems are sealed and are lubricated using lubricant (grease/oil) injected into the bearing by a hydraulic piston assembly.
For a further discussion of downhole drilling motors and their operations, see U.S. Pat. Nos. 3,840,080; 4,246,976; 4,492,276; 5,495,900; 5,090,497; 6,183,226; 6,905,319 and Canadian Patent No. 2,058,080, incorporated by reference.
SUMMARY
The present disclosure pertains to a new improved housing, mandrel and bearing assembly for transmitting power from a source of rotational torque (e.g. a downhole drilling motor output) to the drill bit. Rotational power=torque×RPM/5250. The invention provides a reduced length housing, bearing and mandrel assembly used in downhole drilling operations.
Reduced length provides the following advantages: Ability to more effectively navigate around deviated sections of the wellbore by reducing friction caused as a section of the bottom hole assembly goes in and out of these deviated sections, which ultimately causes premature wear on internal components. Secondly, a reduced bit to bend allows the drill motor to build greater angle with less of an incorporated fix bend to get to desired lateral. This reduced degree bent housing ultimately reduces wear and tear on internal components.
As used in this document, “tubular” refers to a generally cylindrical member with a longitudinal passage therethrough. The longitudinal passage may be formed therein or bored therethrough.
A housing, mandrel and bearing assembly postionable in a wellbore is disclosed herein. In some implementations the assembly includes a torque transmission member (e.g. a flex shaft) having an upper end adapted to receive rotational torque power (e.g. from a downhole motor power output), a lower portion with a longitudinal cavity with an open lower end, at least a portion of said cavity having an internal connector, and a lower end having an external connector. The assembly further includes a tubular mandrel adapted at a lower end to connect to a drill bit, said tubular mandrel having an upper portion of the tubular mandrel with an external surface including a connector adapted to connect to the internal connector in the longitudinal cavity of the torque transmission member, a longitudinal passage through the mandrel from an upper end to the lower end, a shoulder disposed on a portion of the external surface of the tubular mandrel between the upper portion of the tubular mandrel and a lower portion of the tubular mandrel, said upper portion having a first outside diameter d1 and said lower portion having a second outside diameter d2, wherein the second outside diameter d2 is greater than the first outside diameter d1. The assembly further includes a lower tubular housing having a longitudinal passage from an upper end of the lower tubular housing to a lower end of the lower tubular housing, an upper portion having a connector, a shoulder disposed between the upper portion of the lower tubular housing and a lower portion of the lower tubular housing, said upper portion having a first inside diameter d3 and said lower portion having a second inside diameter d4, wherein the second inside diameter d4 is greater than the first inside diameter d3. The assembly further includes an upper tubular housing having a longitudinal passage from an upper end of the upper tubular housing to a lower end of the upper tubular housing, said longitudinal passage having a lower portion with an internal diameter adapted to receive an upper bearing, said lower portion of the longitudinal passage adapted to connect to the connector on the upper portion of the lower tubular housing. An upper bearing disposed in the longitudinal passage of the upper tubular housing contacting the lower end of the torque transmission member and a lower bearing disposed in the longitudinal passage of the lower tubular housing contacting the shoulder of the lower tubular housing. It will be understood by those skilled in the art that various types of thrust bearings and radial bearings, as known in the art, may be used in the practice of this invention.
In some implementations the lower tubular housing has a longitudinal passage from an upper end of the lower tubular housing to a lower end of the lower tubular housing and an upper portion having a connector. The assembly further includes an upper tubular housing having a longitudinal passage from an upper end of the upper tubular housing to a lower end of the upper tubular housing, said longitudinal passage having a lower portion with an internal diameter adapted to receive an upper bearing, said lower portion of the longitudinal passage adapted to connect to the connector on the upper portion of the lower tubular housing. An upper bearing disposed in the longitudinal passage of the upper tubular housing contacting the lower end of the torque transmission member and a lower bearing disposed on the tubular mandrel and contacting the lower tubular housing. It will be understood by those skilled in the art that various types of thrust bearings and radial bearings, as known in the art, may be used in the practice of this invention
In some implementations the assembly may further include an upper preload spring(s) adapted to keep the upper bearing in compression and a lower preload spring(s) adapted to keep the lower bearing in compression.
In some implementations, the assembly may include a tubular catch sleeve disposed on a lower portion of the tubular mandrel. The tubular catch sleeve having an internal passageway adapted to contact the shoulder of the tubular mandrel and an exterior surface adapted to be received in the longitudinal passage of the lower housing. The tubular catch sleeve further includes an upper end having a connector adapted to connect to the lower bearing and a portion of the internal passageway in the tubular catch sleeve having a connector adapted to connect to a connector on a portion of the tubular mandrel. The connector in the internal passageway of the tubular catch sleeve is selected from the group consisting of hex, threaded, spline or pin connectors.
In some implementations the downhole housing, mandrel and bearing assembly may further include at least one radial receptacle disposed in the lower portion of the tubular mandrel for receiving a locking pin to secure the tubular catch sleeve to the tubular mandrel.
The assembly may further include a radial sleeve (e.g. radial bearing) disposed in the lower end of the lower housing around the tubular mandrel and a retaining member that retains the radial sleeve in the lower tubular housing, wherein an upper end of said radial sleeve is adapted to abut a lower end of the tubular catch sleeve when during drilling operations in a wellbore the tubular mandrel shears into an upper and lower portion, and the lower portion of the tubular mandrel is removed with the lower housing from the wellbore.
As noted above, various types of radial and thrust bearings known in the art may be used in the practice of this invention. In some implementations the upper bearing comprises at least an upper race member, a lower race member, and a plurality of thrust balls disposed there between, wherein the upper race member has an upper end adapted to contact the torque transmission member (e.g. flex shaft) thereby securing the upper race to the torque transmission member such that the upper race member rotates with the torque transmission member when the torque transmission member and the tubular mandrel are rotated during drilling operations. The lower race member has a lower end adapted to contact an upper end of the lower tubular housing thereby securing the lower race to the lower tubular housing when the torque transmission member and the tubular mandrel are rotated during drilling operations.
As noted above, various types of radial and thrust bearings known in the art may be used in the practice of this invention. In some implementations, the lower bearing comprises at least an upper race member, a lower race member, and a plurality of thrust balls disposed there between, wherein the lower race member of the lower bearing has a lower end that is adapted to contact the upper end of the catch assembly, thereby securing the lower race member to the tubular catch sleeve as the torque transmission member and the tubular mandrel are rotated during drilling operations. The upper race member of the lower bearing is adapted to contact the shoulder in the lower housing thereby securing the upper race member to the lower housing as the torque transmission member and the tubular mandrel are rotated during drilling operations.
A method of assembling the downhole drilling assembly is disclosed. The method may include providing a tubular mandrel having a bit box at a lower end adapted to connect to a drill bit, said tubular mandrel having an upper portion of the tubular mandrel having a connector adapted to connect a rotatable torque transmission member to a source of rotational torque, a shoulder is disposed on a portion of the tubular mandrel between the upper portion of the tubular mandrel and a lower portion of the tubular mandrel. A radial sleeve is provided and slid over the tubular mandrel from the top and down over the mandrel until the radial sleeve is proximal to the upper end of the bit box. A tubular catch sleeve is then slid over the top of the tubular mandrel and down over the mandrel until a lower connector disposed in an internal passageway through the tubular catch sleeve and is positioned in contact with a connector of the mandrel, such that the tubular catch sleeve abuts the shoulder of the tubular mandrel and the tubular catch sleeve is secured to the tubular mandrel. A lower bearing is then slide over the tubular mandrel and positioned on a top of the tubular catch sleeve.
A lower tubular housing is slid over the tubular mandrel and positioned such that a shoulder of the lower tubular housing contacts the upper end of the lower bearing. An upper bearing is then slid over the mandrel and positioned in contact with the lower tubular housing. A longitudinal cavity in a lower portion of a torque transmission member is positioned over the upper end of the tubular mandrel and connects the torque transmission member to the upper end of the tubular mandrel. An upper tubular housing is positioned over the torque transmission member and the upper tubular housing is connected to the lower tubular housing.
In some implementations, before sliding the radial sleeve over the tubular mandrel, a retaining member is slid downwardly from the upper end of the tubular mandrel until it is proximal to an outer radius of the bit box at the lower end of the mandrel. Then the radial sleeve is slid over the tubular mandrel from the top until it is proximal to the retaining member and the retaining member is inserted into the lower end of the lower housing after sliding the lower tubular housing over the tubular mandrel. The retaining member is adapted to prevent the radial sleeve from sliding out the lower end of the lower tubular housing. Alternatively, after sliding the lower tubular housing over the tubular mandrel the retaining member (e.g. a split retaining ring) is inserted in a lower end of the lower tubular housing.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic illustrating a typical drilling system using a downhole drilling motor assembly.
FIG. 2 is a cross-section of a prior art bearing and bearing mandrel assembly of a prior art downhole motor.
FIG. 2A is a cross-section of the bearing mandrel of the prior art assembly of FIG. 2 .
FIG. 3 is a cross-section of a housing, mandrel and bearing assembly of the present disclosure.
FIG. 4 is an enlarged cross-section of an upper portion of the assembly of FIG. 3 .
FIG. 4A is a cross-section illustrating a portion of a flex shaft of the assembly of FIG. 4 .
FIG. 4B is a lateral cross-section of the flex shaft of FIG. 4A taken at section AA.
FIG. 4C is a cross-section of a bearing assembly member of FIG. 4 .
FIG. 4D is a lateral cross-section of an upper end of the bearing assembly member of FIG. 4 taken at Section AA.
FIG. 4E is a cross-section of the upper end of the lower housing of FIG. 4 .
FIG. 4F is a lateral cross-section of the upper end of the lower housing of FIG. 4 taken at section BB.
FIG. 5 is a cross-section of a lower portion of the assembly of FIG. 3 .
FIG. 5A is a cross-section illustrating a portion of a tubular mandrel and a catch assembly of FIG. 5 .
FIG. 5B is a lateral cross-section of the tubular mandrel and the catch assembly of FIG. 5A taken at section CC of FIG. 5 .
FIG. 5C is a cross-section of a lower bearing assembly of FIG. 5 .
FIG. 5D is a lateral cross-section of the lower bearing assembly of FIG. 5 taken at section DD.
FIG. 6 is a cross-section illustrating the flow of drilling fluid down the drill string, through a downhole drilling motor, through the assembly of FIG. 3 , out a bit and up the annulus of the wellbore.
FIGS. 7A and 7B are a cross-section illustrating the transfer of downward force and upward force from a drill string through the assembly of FIG. 3 to a drill bit.
FIGS. 8A to 8K are partial cross-sections illustrating the sequential steps of assembling the housing, mandrel and bearing assembly of FIG. 3 .
FIGS. 9A and 9B are a cross-section illustrating the assembly of FIG. 3 before failure of the mandrel and after failure of the mandrel, wherein the catch sleeve and radial sleeve maintain the broken mandrel in the assembly.
FIG. 10 is a cross-section of a prior art bearing used in a downhole motor.
FIG. 11 is a cross-section of the upper housing and the upper and the lower bearing assemblies of the assembly of FIG. 3 .
Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
FIG. 1 illustrates a simplified schematic of a drilling operation. A drill string 310 extends to the surface 348 where it is connected to a kelly 320 , mounted in a rotary table 330 of a drilling rig 340 to provide rotation to the drill string 310 when a downhole motor is not used to provide rotation to the bit. Alternatively, top drive systems are suspended in a rig derrick 342 and provide rotation directly to the drill string 310 . Drilling fluid 350 is pumped down through the drill string 310 to the bottom of the bore hole 360 and back up the annulus 362 between the drill string 310 and the wall of the bore hole 360 . The drilling fluid cools the drill bit 370 and removes the cuttings resulting from the drilling operation.
In certain drilling situations, including but not limited to directional drilling, it is useful to use a downhole drilling motor assembly 301 to provide rotation to the bit. In such situations the downhole motor assembly 301 is inserted into the drill string 310 above the drill bit 370 . In the instances where the downhole drilling motor is a hydraulic type, such as a progressive cavity type motor, the drilling fluid 350 also supplies the hydraulic power to operate the motor.
Various types of downhole drilling motors may be employed for the purpose of the invention such as electrical motors and hydraulic motors. Suitable hydraulic motors are turbines, vane motors and Moineau motors. See discussion in background section of this document about various types of drilling motors.
A Moineau motor is very useful for application in the present invention since this type of motor is provided with a flexible connection between the rotor and power output shaft to compensate the eccentric movement of the rotor in the housing during operation of the motor. The invention is not restricted to the use of a Moineau motor. Any type of downhole motor known in the art may be used with the bearing mandrel and bearing assembly of the present invention.
FIG. 2 illustrates a partial cross-section of a prior art downhole motor bearing assembly and bearing mandrel assembly. A downhole drilling motor (not shown) transmits power from the motor power output 491 to a bearing mandrel 490 that contacts radial bearings 493 and thrust bearings 492 housed in a bearing housing 494 . The mandrel's distal (lower) end 497 includes a bit box 498 connection for connection to a drill bit. The box connection results in assembly configurations that does not allow the mandrel to be assembled by insertion of the mandrel through the proximal (upper end) 499 of the bearing housing 494 . These prior art configurations have mandrels with stepped down profiles 496 on which a bearing spacer 495 makes contact. FIG. 2A illustrates one embodiment of a cross-section of the prior art bearing mandrel 490 .
As weight is applied on the bit, a downward force DF will move down the drill string through the motor and to the mandrel 490 . As the mandrel 490 moves downward, bearing spacer 491 will push thrust bearings 492 down. Bearing spacer 495 will contact mandrel 490 at the step down 496 . When it does, it will provide weight to the bit to start drilling. An equal and opposite upward force UF will be exerted by the bottom of the bore hole below the bit.
FIG. 3 illustrates a partial cross-section of a downhole motor assembly 301 that includes a tubular housing 302 that is preferably formed of steel. Disposed within the tubular housing 302 is a power unit having a stator 306 and a rotor 308 connected to a power output assembly 309 . The power output assembly 309 may be attached directly to the housing, mandrel and bearing assembly 100 according to one embodiment of the present invention or may include intermediate assemblies that ultimately connect to the housing, mandrel and bearing assembly 100 of the present invention.
Referring to both FIGS. 1 and 6 , in operation, drilling fluid 350 (also known in the art as drilling mud) is pumped down the interior of a drill string attached to the downhole drilling motor 301 . Drilling fluid 350 enters the drilling motor 301 having a pressure that is a combination of pressure imposed on the drilling fluid by pumps at the surface and the hydrostatic pressure of the above column of drilling fluid 350 . The pressurized fluid entering a cavity in the motor, in cooperation with the lobes of the stator 306 and the geometry of the stator 306 and rotor 308 causes the lobes of the stator to deform and the rotor to turn to allow the drilling fluid 350 to pass through the motor 301 . Drilling fluid 350 subsequently exits through ports (referred to in the art as jets) in drill bit 370 and travels up the annulus 362 between the bit 370 , the assembly 100 of the present invention and the downhole motor assembly 301 and drill string 310 , and is received at the surface 348 where it is captured and pumped down the drill string 310 again.
Referring to FIGS. 3 through 5D , therein is illustrated one embodiment of a downhole housing, mandrel and bearing assembly 100 of the present invention. The assembly has a torque transmission member (e.g. flex shaft 20 ) with an upper end 21 adapted to connect to a downhole motor power output 309 . The flex shaft has a lower portion 27 with a longitudinal cavity 23 , at least a portion of said cavity having female threads 24 and a lower end 25 having a male hex connector 26 . It will be understood that other forms of connectors such as spline connectors, pins and threaded connectors may be used.
The assembly further includes a tubular mandrel 30 adapted at a lower end 31 to connect to a drill bit. The outer surface of the mandrel is generally cylindrical (except as noted herein) with an outer diameter that is smaller than the inner diameter of an upper housing 70 and a lower housing 60 , allowing the mandrel to rotate in the housings. The mandrel has an upper portion 33 with an outer surface containing male threads 34 adapted to connect to the female threads 24 of the lower portion 27 of the flex shaft 20 . The mandrel includes a longitudinal passage 32 through the mandrel from an upper end 35 to the lower end 31 . A shoulder 37 is disposed between the upper portion 33 having a first outside diameter d1 and a lower portion 36 having a second outside diameter d2, wherein the second outside diameter d2 is greater than the first outside diameter d1. A series of flats (see FIGS. 5 and 5B ) are disposed on the outer surface in the lower portion 36 of the mandrel 30 to form a male hex connector 38 upon which a catch assembly 110 is positioned. It will be understood that the series of flats may be six as in a hex connector or may be 2 or more flats that are sized and configured to mate with an interior surface of the catch assembly 110 and connect the mandrel to the catch assembly such that the catch assembly rotates with the mandrel during drilling operations, and does not rotate about the mandrel. It will be understood that other forms of connectors such as spline connectors, pins and threaded connectors may be used.
The assembly further includes a lower tubular housing 60 having a longitudinal passage 66 from an upper end 61 of the housing to a lower end 63 of the housing. The lower tubular housing includes an upper portion 65 having male threads 68 disposed on at least a portion of an external surface. A shoulder 67 is disposed between the upper portion 65 having a first inside diameter d3 and a lower portion 69 having a second inside diameter d4 wherein the second outside diameter d4 is greater than the first outside diameter d3. The upper end 61 further includes a male hex connector 62 . It will be understood that the male connector may include a series of 6 flats as in a hex connection or may include two or more flats wherein the flats are configured to mate with a female connector of a bearing race member 87 to be joined to the male connector 62 . It will be understood that other forms of connectors such as spline connectors, pins, and threaded connectors may be used.
The assembly further includes an upper tubular housing 70 having a longitudinal passage 76 from an upper end 71 of the housing to a lower end 73 of the housing. The passage has a lower portion 74 with an internal diameter adapted to receive an upper bearing assembly 80 . The lower portion 74 of the internal passage 76 has female threads 75 disposed on at least a portion of an internal surface of the internal passageway, said threads adapted to connect to the male threads 68 of the upper portion of the lower tubular housing 60 . The upper housing further includes an upper portion 77 adapted to connect to a stator 302 of a downhole drilling motor 301 .
The assembly 100 further includes an upper bearing assembly 80 (see FIGS. 4 and 5 ) disposed in the internal passageway 76 of the upper housing 70 , wherein the upper bearing assembly has at least three bearing race members each having a generally cylindrical body. An upper end race member 82 has an upper end having an upper female hex box connector 83 (see FIGS. 4C and 4D ) adapted to receive the male hex connector 26 of the flex shaft 20 (see FIGS. 4A and 4B ). The hex connector secures the upper race 82 to the flex shaft such that the upper race rotates with the flex shaft and with the mandrel 30 as the flex shaft and mandrel are rotated in drilling operations. It will be understood that other forms of connectors such as spline connectors, pins and threaded connectors may be used. A middle race member 86 is disposed below the upper race member 82 and separated by a plurality of thrust balls 85 . The middle race section 86 is free to rotate with and about the mandrel during drilling operations. A lower end race member 87 is disposed below the middle race member 86 . The lower race member has a lower end that includes a lower female hex box connector 89 that secures the lower race member to the male hex connector 62 at the upper end 61 of the lower tubular housing 60 (see FIGS. 4E and 4F ). It will be understood that other forms of connectors such as spline connectors, pins and threaded connectors may be used. Therefore, the lower end race member 87 is fixed to the lower housing 60 and does not rotate with the mandrel 30 . A plurality of thrust balls 85 are disposed between the middle race member 86 and the lower race member 87 .
The assembly further includes a lower bearing assembly 90 disposed in the internal passageway 66 of the lower housing 60 , wherein the bearing assembly has an upper race member 92 that is adapted to be received in the shoulder 67 of lower housing 60 . Upper race member 92 may rotate about the mandrel during rotation of the mandrel during drilling operations. A middle race member 96 is disposed below the upper end race member 92 and separated by a plurality of thrust balls 95 (see FIGS. 5D and 5C ). The middle race section 96 is free to rotate with and about the mandrel during drilling operations. A lower end race member 93 is disposed below the middle race member 96 . The lower race member has a lower end that includes a lower female hex box connector 94 that secures the lower race member to a male hex connector 116 at the upper end of a catch assembly 110 (see FIGS. 5A and 5B ). It will be understood that other forms of connectors such as spline connectors, pins and threaded connectors may be used. Therefore, the lower race member 93 is fixed to the catch assembly 110 and rotates with the mandrel 30 . The catch assembly 110 is secured to the mandrel as described later herein. Therefore, the race member 93 rotates with the mandrel. A plurality of thrust balls 85 are disposed between the middle race member 96 and the lower race member 93 (see FIGS. 5C and 5D ).
The assembly further includes an upper preload spring assembly 130 disposed in an exterior circumferential recess 29 in the lower portion 27 of the flex shaft 20 . The spring assembly has a first resilient member 131 with a first end contacting a ledge 28 in recess 29 and a second end contacting a first end of a spacer member 132 ; and a second resilient member 133 with a first end contacting a second end of spacer member 132 and a second end contacting the upper end of the upper bearing assembly member 82 .
The assembly further includes a lower preload spring assembly 140 disposed in an exterior circumferential recess 119 in catch sleeve 110 . The spring assembly has a first resilient member 141 with a first end contacting a ledge 113 in recess 119 and a second end contacting a first end of a spacer member 142 ; and a second resilient member 143 with a first end contacting a second end of spacer member 142 and a second end contacting the lower end 97 of the lower bearing assembly 90 .
The assembly further includes a radial sleeve 120 disposed in the lower end 63 of the lower housing 60 . The radial sleeve 120 is locked within the lower housing by vertical dowel pin 124 that maintains the radial sleeve rotating with the lower housing around the mandrel during motor operation. The radial sleeve is held within the housing 60 with the retaining ring 122 . This retaining ring 122 serves to hold the radial sleeve within housing 60 and extract the lower mandrel 30 and catch sleeve 110 in the event of a fracture within the upper section of the mandrel (see FIGS. 9A and 9B ).
The assembly further includes a catch sleeve 110 having an internal passageway 112 adapted to contact the shoulder 37 of the tubular mandrel. The catch sleeve further includes an exterior surface adapted to be received in longitudinal passageway 66 of lower housing 60 , and an upper end 115 having an upper male hex connector 116 adapted to receive the female hex connector 94 of the bearing 90 . As illustrated in FIGS. 5 , 5 A and 5 B, the tubular mandrel 30 has a portion of the exterior surface wherein the outer perimeter is configured as a hexagon in the portion of the mandrel on which the catch sleeve 110 is disposed. The catch sleeve passageway has an internal surface wherein the perimeter is configured as a hexagon adapted to mate with the outer surface of the tubular mandrel. It will be understood that other forms of connectors such as spline connectors, pins and threaded connectors may be used. When the catch sleeve 110 is in position the catch sleeve will move with the rotating mandrel during drilling operations, not about the mandrel. The assembly 100 further includes at least two radial receptacles 39 disposed in the lower portion 36 of the tubular mandrel, each of said receptacles is adapted to receive a locking pin 41 . The pins secure the catch assembly to the mandrel.
The unique design of the assembly 100 provides many advantages over the prior art designs. For example, if the mandrel 30 were to break above the catch sleeve the mandrel can be removed from the wellbore 360 together with the upper 70 and lower 60 housings using the drill string 310 . This configuration is desirable as it prevents the undesirable situation of leaving a portion of broken mandrel 30 and drill bit 370 in the wellbore, which must be retrieved in a difficult operation often referred to in the art as “fishing.” Due to the unique configuration of the assembly of the present invention the broken mandrel 30 and drill bit 370 would be pulled from the wellbore using the drill string. Because of the configuration of the catch sleeve 110 , the mandrel 30 and lower housing 60 , the mandrel will not fall out of the lower housing 60 and be left in the wellbore 360 .
Referring now to FIG. 7A , wherein the transfer of downward force DF through the assembly 100 to the bit 370 during drilling operations is illustrated. Downward force DF is transmitted through the upper housing 70 and lower housing 60 through the lower bearing 90 and catch sleeve 110 to the shoulder 37 of the mandrel 30 and through the mandrel to the bit 370 . When pulling the drill string 310 from the hole, removal force RF is transferred through the upper bearing 80 to the flex shaft 20 which is connected to the mandrel 30 , and through the mandrel 30 to the bit 370 (see FIG. 7B ).
FIGS. 8A to 8K are partial cross-sections illustrating the sequential steps of assembling the housing, mandrel and bearing assembly of FIG. 3 . In step 1 , the mandrel 30 , as illustrated in FIGS. 3 , 4 and 5 , and described above, is provided. A retaining ring 122 is slid downward from the top of the mandrel 30 until it rests on an outer radius of the bit box (See FIG. 8A ).
In step 2 , a radial sleeve 120 is slid over the mandrel from the top until it rests on the retaining ring (see FIG. 8A ).
In step 3 (see FIG. 8B ), a catch sleeve 110 is slid over the top of the mandrel until the lower female hex connector is positioned over the male hex connector of the mandrel and the catch sleeve abuts the shoulder 37 of the mandrel.
In step 4 (see FIG. 8B ), locking pins 41 are inserted into receptacles 39 in mandrel 30 to secure the catch sleeve to the mandrel.
In step 5 (see FIG. 8C ), one or more lower preload spring assemblies 140 are inserted onto the catch sleeve and positioned in recess 119 of the catch assembly 110 .
In step 6 (see FIG. 8D ), lower bearing assembly 90 is slid over the mandrel and positioned on the top of catch sleeve 110 .
In step 7 (see FIG. 8E ), lower housing 60 is slid over the mandrel and positioned such that a ledge contacts the upper end of the lower bearing assembly. Retaining ring 122 is inserted into the lower end of the lower housing. The retaining ring 122 keeps the radial sleeve 120 from falling out the lower end of the housing 60 .
In step 8 (see FIG. 8F ), upper bearing assembly 80 is slid over the mandrel and positioned with the lower female hex connector of the bearing assembly onto the upper male hex connector of the lower housing.
In step 9 (see FIG. 8G ), preload spring assembly 130 is slid over the mandrel and positioned adjacent the bearing assembly 80 to bias the bearing assembly members together and in contact with the housing 60 .
In step 10 (see FIG. 8G ), flex shaft 20 is positioned over the upper end of the mandrel and threadedly connected to the upper end of the mandrel.
In step 11 (see FIG. 8H ), upper housing 70 is positioned over the flex shaft 20 and threadedly connected to lower housing 60 .
In step 12 (see FIG. 8I ), the power output 309 and rotor 308 of downhole motor 301 is connected to the flex shaft 20 .
In step 13 (see FIG. 8J ), the stator 306 and motor housing 302 is positioned over the rotor and upper end of the flex shaft.
In step 14 (see FIG. 8K ), the upper end of motor housing 302 is connected to a cross-over sub that is connected to drill string 310 .
Referring to FIG. 10 , wherein a cross-section of a prior art bearing system 580 inside housing 560 is illustrated. The bearing races are formed from an inside member 582 and an outside member 584 . This assembly requires more machining and assembly time than the bearing assemblies 80 and 90 of the present invention (see FIG. 11 ). Bearing assemblies 80 and 90 are separated by housing 60 .
Bearing races 82 , 86 , 87 , 92 , 96 , and 93 are a single construction saving time and money in manufacturing an assembly when compared to prior art assembly 560 .
It will be understood that threaded and hex connectors have been disclosed and described in the drawings and specifications; the present invention may use various types of connectors.
A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. | A housing, mandrel and bearing assembly positionable in a wellbore includes a torque transmission member adapted to connect to a source of rotational torque (e.g. A downhole motor power output) and a tubular mandrel adapted to connect to a drill bit. A lower tubular housing is adapted to contain a lower bearing and catch sleeve assembly. The catch assembly is adapted to retain the mandrel in the lower housing if the mandrel breaks. An upper tubular housing contains an upper bearing and is adapted to connect to a housing of the downhole motor. A method of assembling the downhole housing, mandrel and bearing assembly is disclosed. |
TECHNICAL FIELD
[0001] Embodiments described herein generally relate to methods for repairing composite containment casings. More specifically, embodiments herein generally describe methods for repairing composite fan casings having integrated abradable systems.
BACKGROUND OF THE INVENTION
[0002] In gas turbine engines, such as aircraft engines, air is drawn into the front of the engine, compressed by a shaft-mounted compressor, and mixed with fuel in a combustor. The mixture is then burned and the hot exhaust gases are passed through a turbine mounted on the same shaft. The flow of combustion gas expands through the turbine which in turn spins the shaft and provides power to the compressor. The hot exhaust gases are further expanded through nozzles at the back of the engine, generating powerful thrust, which drives the aircraft forward.
[0003] Because engines operate in a variety of conditions, foreign objects may undesirably enter the engine. More specifically, foreign objects, such as large birds, hailstones, ice, sand and rain may be entrained in the inlet of the engine where they may impact the engine or a fan blade therein. Sometimes these impacts can result in a portion of the contacted blade being torn loose from the rotor, which is commonly known as fan blade out. The loose fan blade may then impact the interior of the fan casing. Similarly, in cold weather and at high altitudes, ice can form and accumulate on the fan blades. When engine speed is rapidly accelerated, or altitude is decreased, the ice can shed, also resulting in an impact with the interior of the fan casing.
[0004] In recent years composite materials have become increasingly popular for use in a variety of aerospace applications because of their durability and relative lightweight. Although composite materials can provide superior strength and weight properties, and can lessen the extent of damage to the fan casing during impacts such as ice shedding and fan blade outs, there remains room for improvement.
[0005] Current composite containment technology, such as that used to make fan casings, typically employs a thick, monolithic hardwall design that is capable of withstanding an impact caused by ice and/or released fan blades, and also fragmentizing the ice or released fan blades, breaking them into smaller pieces. These fragmentized pieces can then be purged from the engine without causing significant damage to either the engine or the body of the aircraft. The construction of the fan casing provides for the dissipation of impact energy using any of a number of mechanisms including fiber/matrix interference failure, matrix microcracking and ply delamination.
[0006] More specifically, current hardwall designs generally consist of an abradable system having an abradable layer attached to a substrate structure that includes a glass/epoxy composite face sheet bonded to a Nomex® honeycomb core, which can be very lightweight. See U.S. Pat. No. 5,344,280 to Langenbrunner et al. However, such honeycomb cores are typically not designed to provide significant energy absorption during a fan blade out event. More specifically, the design of the honeycomb core results in an abradable system having radial weakness. Thus, released fan blades will have a tendency to simply cut through the honeycomb core upon impact, leaving roughly 99% of the impact energy to be absorbed by the fan casing body. Moreover, because the current abradable systems require numerous layup, bonding, cure, and machining cycles, the fabrication of such systems can be labor intensive, costly, and can result in a heavier than desired fan casing because of the multiple layers of construction. Additionally, because the abradable system is fabricated separately from, and then attached to, the fan casing, the two parts function independently, rather than as a unitary system.
[0007] Accordingly, there remains a need for methods for repairing integrated abradable systems for containment fan casings that can provide improved impact resistance without the previously described time, labor, weight and cost issues.
BRIEF DESCRIPTION OF THE INVENTION
[0008] Embodiments described herein generally relate to methods for repairing composite containment casings comprising providing a composite containment casing having an integrated abradable system, the abradable system having at least one damaged portion, and comprising a sandwich structure, and at least one abradable layer, removing the damaged portion of the abradable system to leave a hole, shaping a sandwich structure segment to produce a shaped sandwich structure, placing the shaped sandwich structure into the hole in the abradable system, infusing a resin into the shaped sandwich structure, and curing the containment casing having the shaped sandwich structure, and applying at least one abradable layer to the shaped sandwich structure to produce the containment casing having a repaired integrated abradable system.
[0009] Embodiments herein also generally relate to method for repairing composite containment casings comprising providing a composite containment casing having an integrated abradable system, the abradable system having at least one damaged portion, and comprising a sandwich structure and at least one abradable layer, removing the damaged portion of the abradable system to leave a hole, shaping a sandwich structure segment to produce a shaped sandwich structure, infusing a resin into the shaped sandwich structure, curing the shaped sandwich structure, bonding the shaped sandwich structure in the hole in the abradable system, and applying at least one abradable layer to the shaped sandwich structure to produce the containment casing having a repaired integrated abradable system.
[0010] These and other features, aspects and advantages will become evident to those skilled in the art from the following disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] While the specification concludes with claims particularly pointing out and distinctly claiming the invention, it is believed that the embodiments set forth herein will be better understood from the following description in conjunction with the accompanying figures, in which like reference numerals identify like elements.
[0012] FIG. 1 is a schematic cross-sectional view of one embodiment of a gas turbine engine in accordance with the description herein;
[0013] FIG. 2 is a schematic cross-sectional view of a portion of one embodiment of a fan casing having an integrated abradable system in accordance with the description herein;
[0014] FIG. 3 is a schematic perspective view of one embodiment of a mandrel having a pocket in accordance with the description herein;
[0015] FIG. 4 is a schematic cross-sectional view of a portion of the mandrel of FIG. 3 taken along line A-A having a sandwich structure positioned in the pocket and material wrapped thereabout in accordance with description herein; and
[0016] FIG. 5 is a schematic cross-sectional view of a portion of one embodiment of a fan casing having an integrated abradable system and the system's position relative to a fan blade in accordance with the description herein.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Embodiments described herein generally relate to methods for repairing composite containment casings having integrated abradable systems. Those skilled in the art will understand that the following description is applicable to all types of gas turbine engines, including but not limited to Low Bypass Fan Engines, High Bypass Fan Engines and Ultra-High Bypass Fan Engines.
[0018] Turning to the figures, FIG. 1 is a schematic representation of one embodiment of a conventional gas turbine engine 10 that generally includes a fan assembly 12 and a core engine 14 . Fan assembly 12 may include a composite fan casing 16 having a body 17 , and an array of fan blades 18 extending radially outwardly from a rotor disc 20 . Core engine 14 may include a high-pressure compressor 22 , a combustor 24 , a high-pressure turbine 26 and a low-pressure turbine 28 . Engine 10 has an intake end 30 and an exhaust end 32 .
[0019] As previously described, embodiments herein may comprise a fan casing having an integrated abradable system 35 adjoined thereto that can lessen the damage resulting from a fan blade out or other like event. While the abradable system 34 may take a variety of configurations, it may generally comprise a sandwich structure 36 and at least one abradable layer 38 , as shown in FIG. 2 . As used herein, “sandwich structure” refers to a multi-layered structure generally comprising a first facesheet 33 , and a second facesheet 33 positioned about at least one core layer 37 , as shown in FIG. 2 . First and second facesheet 33 , as well as core layer 37 , may comprise any woven, braided, or non-crimp fabric capable of being infused with a resin and cured to produce a composite material, such as carbon fibers, graphite fibers, glass fibers, ceramic fibers, and aramid polymer fiber. Moreover, the material used in core layer 37 can have non-isotropic properties, and may include cell, columnar, and truss configurations. A plurality of core layers 37 may be desirable to permit tailoring of the orthotropic properties of sandwich structure 36 as a function of the fan casing radius or thickness.
[0020] Some examples of materials suitable for use as sandwich structure 36 can include, but should not be limited to, TYCOR® (WebCore Technologies, Inc., Miamisburg, Ohio, see U.S. Patent Application 2005/0074593) shown in FIG. 2 , or 3-D woven truss configurations (Bally Ribbon Mills, Bally, Pa., see U.S. Pat. Nos. 6,742,547 and 6,892,766) shown in FIGS. 4 and 5 .
[0021] It is envisioned that during the fabrication process, sandwich structure 36 can be designed to be strong radially and weak circumferentially. Radial strength will allow for the absorption and dissipation of impact energy generated by a released fan blade, as well as the alteration of the released blade's flight trajectory. Circumferential weakness will allow for sandwich structure 36 to become crushed and deformed when impacted by a fan blade due to unbalanced rotor orbiting. Taken together, this radial strength and circumferential weakness can allow the sandwich structure 36 to help absorb energy generated by a released fan blade, thereby reducing the energy that will need to be absorbed by the fan casing. This can lead to the fabrication of a thinner, lighter fan casing. Additionally, sandwich structure 36 can maintain its mechanical integrity, thereby reducing the likelihood the released fan blade will contact and/or significantly damage the fan casing.
[0022] Abradable layer 38 refers to the radially innermost layer of integrated abradable system 34 and provides a region against which the fan blades may occasionally rub throughout engine operation. Abradable layer 38 may generally comprise any low-density, syntactic film epoxy suitable for use in a clearance control application that can be resistant to damage from ice impact and can be easily repaired/replaced throughout the service life time of the fan casing, as explained herein below. One example of a suitable material for use as abradable layer 38 is Hysol® EA 9890, though the embodiments herein should not be limited to such. Additionally, abradable layer 38 can be bonded to the fan casing so as to cover sandwich structure 36 . Any conventional bonding materials and techniques known to those skilled in the art may are acceptable for use herein.
[0023] In general, a fan casing having an integrated abradable system 35 can be made using conventional composite manufacturing processes. However, some modifications to the tooling used in the process are required. As shown in FIG. 3 , a mandrel 40 may be provided for fabricating embodiments of the fan casing described herein. Mandrel 40 may be similar to conventional tools used in fan casing fabrication, see for example, U.S. Patent Application No. 2006/0134251 to Blanton et al., with the exception that mandrel 40 can have a pocket 42 disposed circumferentially thereabout for receiving truss core layer 36 of abradable system 34 . Mandrel 40 can be “substantially cylindrical,” and may be generally shaped like a cylinder, either with or without a contour.
[0024] More specifically, and as shown in FIG. 3 , pocket 42 may have any dimension that corresponds to the desired dimensions of sandwich structure 36 of abradable system 34 . However, in general, pocket 42 (and therefore sandwich structure 36 ) can have a width W of from about one to about three times the axial chord length L of fan blade 18 as indicated in FIG. 1 , and a depth D of from about one to about five times the radial thickness T of fan casing. “radial thickness” is measured at the thickest cross-section of the fan casing, as shown in FIG. 5 . As an example, if fan blade 18 comprises an axial chord length L of about 12 inches (about 30.4 cm) and fan casing preform 46 comprises a radial thickness T of about 1 inch (about 2.54 cm), then pocket 42 may have a width W of from about 12 inches (about 30.4 cm) to about 36 inches (about 91.4 cm) and a depth D of from about 1 inch (about 2.54 cm) to about 5 inches (about 12.7 cm). Moreover, because abradable system 34 functions to absorb impact from a released fan blade, pocket 42 can be positioned along mandrel 40 such that sandwich structure 36 , and therefore abradable system 34 , will be adjacent to fan blades 18 when the fan assembly of the engine is assembled, as shown in FIG. 5 .
[0025] Fabrication of fan casing having integrated abradable system 35 can be accomplished in a couple of ways. In one embodiment, sandwich structure 36 having the desired number of core layers 37 may first be positioned within pocket 42 of mandrel 40 , as shown in FIG. 4 . Next, at least one ply of a material 44 may be continuously applied about mandrel 40 having pocket 42 containing sandwich structure 36 until the desired thickness is obtained. Similar to facesheet 33 of sandwich structure 36 , material 44 may comprise any woven, braided, or non-crimp fabric capable of being infused with a resin and cured to produce a composite material. In one embodiment, the material may comprise carbon fibers, graphite fibers, glass fibers, ceramic fibers, and aramid polymer fibers. Additionally, each fiber tow may comprise from about 3000 to about 24,000 individual fiber filaments.
[0026] The resulting fan casing preform 46 having an integrated sandwich structure 36 , may be treated with any suitable resin, such as epoxy, using conventional techniques for infusing the resin throughout the fan casing preform 46 and the integrated sandwich structure 36 . Once the resin has been infused, fan casing preform 46 may then be cured using traditional curing methods known to those skilled in the art.
[0027] In an alternate embodiment, fan casing preform 46 can be layed up about a conventional mandrel using conventional techniques, followed by resin infusion and curing. The resulting fan casing may then have sandwich structure 36 , which has been previously resin-infused and cured, bonded to interior 19 thereof. Like the previous embodiment, sandwich structure 36 can be positioned adjacent to fan blades 18 when the fan assembly of the engine is assembled, as shown in FIG. 5 .
[0028] Whichever method of fabrication is selected, to complete fan casing having abradable system 35 , at least one abradable layer 38 may be applied over sandwich structure 36 , as shown in FIG. 5 , using any suitable method, including, but not limited to, adhesively bonding or mechanically attaching. Further finishing steps conventional to all fan casing fabrication processes, such as the application of one or more acoustic panels 48 , may then be carried out.
[0029] The integrated abradable systems of the fan casing embodiment described herein can provide several benefits in addition to those previously discussed. For example, the fan casing embodiments herein can require significantly fewer layup, bonding, cure, and machining cycles than conventional fan casings due to the integrated nature and construction of the abradable system. Moreover, because the sandwich structure core layer(s) can be made from any non-metallic, composite materials, the abradable systems herein can better absorb impact energy, yet still be lightweight. In particularly, the embodiments of abradable system described herein can absorb up to about 25% of the impact energy generated by a released fan blade, leaving only about 75% of the impact energy to be absorbed by the body of the fan casing. By “impact energy,” it is meant the kinetic energy of the released fan blade. This allows the thickness and, therefore, the weight, of fan casing 35 to be reduced.
[0030] Another benefit provided by the presently described embodiments is ease of repair. Those skilled in the art will understand that the entire abradable system need not be removed and reapplied if the damage is limited to only a portion thereof. Rather, should a portion of the abradable system become damaged by ice shedding, a fan blade out, or other like occurrence, that portion only can be replaced. Similar to fabrication, repair may be carried out in a couple of ways. In one embodiment, the damaged portion of the abradable system can be machined, or cut, out of the fan casing using conventional methods leaving a hole in the abradable system. A sandwich structure segment, which can comprise any number of core layers and facesheets as needed, may then be shaped to the proper dimensions need to fill the hole and to create a shaped sandwich structure. The shaped sandwich structure may then be positioned within the hole in the abradable system and resin may be infused therein. The fan casing having the shaped sandwich structure may then be cured to produce a fan casing having a repaired integrated abradable system.
[0031] In an alternate embodiment, the damaged portion of the abradable system can again be machined out using conventional methods to create a hole in the abradable system. A sandwich structure segment may be shaped to the proper dimensions need to fill the hole in the abradable system and to create a shaped sandwich structure. In this embodiment, the shaped sandwich structure may first be infused with resin and cured before being placed into hole and bonded to the abradable system to produce a fan casing having a repaired integrated abradable system. Those skilled in the art will understand that any acceptable adhesive or other like material may be used to bond the shaped sandwich structure in the hole on the abradable system.
[0032] Regardless of the method of repair utilized, after bonding the filler sandwich structure to the fan casing, a new abradable layer may be applied to the filler sandwich structure in the manner described previously.
[0033] The repaired fan casing having the integrated abradable system can provide all of the benefits described previously. In addition, the ability to repair only the damaged portion of the fan casing can reduce the time and expense that would otherwise be involved in replacing the entire abradable system.
[0034] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. | Methods for repairing composite containment casings involving providing a composite containment casing having an integrated abradable system, the abradable system having at least one damaged portion, and including a sandwich structure, and at least one abradable layer, removing the damaged portion of the abradable system to leave a hole, shaping a sandwich structure segment to produce a shaped sandwich structure, placing the shaped sandwich structure into the hole in the abradable system, infusing a resin into the shaped sandwich structure, and curing the containment casing having the shaped sandwich structure, and applying at least one abradable layer to the shaped sandwich structure to produce the containment casing having a repaired integrated abradable system. |
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
TECHNICAL FIELD
This invention relates to the field of processing switch transactions in a communications-networking environment.
BACKGROUND OF THE INVENTION
A telecommunications network is composed of a variety of components. In addition to routers, signal-control points, and hubs, switches are ubiquitous components found in almost all communications networks. Switches process configuration transactions. Transactions can perform a variety of tasks. A transaction may be as simple as an entry or update in a database or as complex as processing a set of sequences that perform an ultimate task. As is appreciated in the art, a typical task for a transaction to complete is to add, delete, or otherwise modify data in a switch table.
Two types of data are common in a telecommunications-network environment: business data and administrative or transaction data. As used herein, business data refers to longer-term data that describes physical aspects of a network. Exemplary business data includes NPA-NXX codes, switch identifiers, trunk identifiers, trunk-group identifiers, station ranges, point of presence identifiers, network-element addresses, component locations, and the like. Transaction data is short-term data substantially limited to the lifespan of a transaction. Exemplary transaction data includes data such as a transaction ID, a time stamp, a status identifier, request information, a requestor's name, etc. Historically, business data has been stored in the same tables as transaction data. Although such a scheme may have been adequate for simple communications networks, it is an inefficient data model that suffers from several disadvantages that are exemplified in a complex communications network.
A first problem associated with storing business data and transaction data in a common table is data duplication. That is, data is unnecessarily repeated across many tables. For instance, a first table may store a transaction ID, a time stamp, and a first parameter. For certain business reasons, a second table may store the same transaction ID and maybe even a time stamp, but a second parameter. Historically, data has been stored in different databases to suit the needs of a communications carrier. For example, data associated with communications feeds has been maintained separately from business data, which has in turn been maintained separately from switch data. To the extent a table stores business data along with transaction data, then as the transaction data changes, the table or tables must also be updated, which leads to a second problem with storing business data with transaction data: updating tables is difficult.
If a first table having transaction data needs to be updated, then so too do all tables that share that common transaction data. Thus, either a user or application would need to update several tables associated with only a single change. Moreover, updating tables that share transaction data with business data is difficult because the data types of the various tables may be different. For example, a transaction ID field of a first table may be formatted to receive numerical input only. But a transaction ID field of a second table may be configured to accept data as a text string. Thus, to update both tables with a new transaction ID, the data would first need to be formatted as a number and then formatted as a text string. In other situations, data masks may be applied in some tables but not in other tables. In still other situations, a data field of a first table may accept data having a certain number of digits, while a sister table may accept data associated with the same field but require a different number of digits. Thus, having to reconcile multiple formats for the same data file types was a laborious and time-intensive task.
A third problem associated with grouping transactional data with business data relates to fault recovery. Historically, recovering from an error transaction has been complicated by a lack of information available. In order to recover from an error transaction, one needs to know where the transaction failed so that it can be started up again at that point. However, determining where a transaction failed using methods available in the prior art has not allowed analysts to precisely determine where a transaction has failed, which highlights a fourth shortcoming of the prior art. The prior art does not offer the ability to establish an audit trail associated with a transaction's progress.
Traditionally, old status data has been overwritten with new status data. Overriding status data deprives an analyst of visibility as to prior happenings within the switch. The lack of ability to establish an audit trail removes the ability for a user to identify at what point during a transaction's progression the transaction failed. Moreover, without an audit trail, no metrics associated with transaction-processing characteristics can be gleaned; this makes inefficiencies difficult if not impossible to identify and prohibits benchmarking for users. That is, no evaluation can be made at a user level.
The prior art could be improved by providing a system and method for maintaining a record of transaction data related to but separate from business data in a telecommunications-networking environment.
SUMMARY OF THE INVENTION
The present invention solved at least the above problems by providing a system, method, and data structure for separating transaction-dependent data from transaction-independent data. In one embodiment, the present invention separates transaction data from its corresponding source, or business data. The present invention has several practical applications in the technical arts including reducing or eliminating data duplication. As a transaction progresses, only data associated with the transaction progression needs to be provided, but not business data associated with the transaction.
Moreover, the present invention greatly simplifies updating a transaction's status. More than just updating a transaction status, the present invention allows greater detail associated with the status of a transaction's progress to be provided. No longer is there a need to update several tables or to format data differently for different fields that store a common data item. Also, the present invention enhances troubleshooting. By establishing an audit trail, the present invention does not overwrite old data with new data.
Rather, the present invention maintains a historical log associated with a transaction's progression. This allows metrics about transaction-processing characteristics to be gained. With these metrics, users can establish benchmarking for evaluation purposes and to identify users that need to be trained. The present invention allows rapid identification of transaction inefficiencies by creating an audit trail. Thus, the present invention can rapidly identify faults by monitoring the progression of a transaction through a communications network and logging data associated with the progress of the transaction in one or more memories that store data distinct from business data.
In a first aspect, computer-readable media having computer-useable instructions for tracking the progression of a switch transaction is provided. The method includes creating an audit trail associated with the switch-transaction progression, iteratively updating the audit trail incident to an occurrence of designated transaction-processing substeps without overwriting previously stored data, and processing the audit trail so that it is available for access by a user interface.
In a second aspect, a machine-implemented method is provided for facilitating telecommunications-network configuration-transaction processing. The method includes maintaining a first table that stores transaction-independent data and a second table that stores transaction-dependent data. The tables are linked by a transaction identifier so that without user intervention, the second table (but not the first table) is iteratively updating incident to the occurrence of certain predestined substeps of the configuration transaction.
In a third aspect, a memory is provided for storing data associated with creating a transaction-audit trail for access by an application program being executed on a computing device. The present invention includes both information used by application programs and information regarding physical interrelationships within a memory. The memory includes a first data structure stored that includes a transaction-progression table that tracks transaction statuses respectively associated with completing a plurality of subtransaction steps. The memory also includes a set of computer-useable instructions that prevent subsequent transaction statuses from overwriting previous transaction statuses.
In a fourth aspect, the present invention includes computer-readable media having stored thereon a data structure for monitoring the progression of a telecommunications switch transaction. The data structure includes a first table that stores a transaction-request identifier, a first set of data that does not change as the switch transaction progresses toward completion, and no data that does change as the switch transaction progresses toward completion. A second table is logically associated with the first table and is iteratively updated as the switch transaction progresses toward completion. The second table stores the transaction-request identifier and a second set of data that do changes as the switch transaction progresses toward completion. The data that does change can be limited to the lifespan of a configuration-transaction request and includes an indication of the request's status at some point in time or interval.
In a final exemplary aspect, the present invention includes a method for increasing the efficiency of a communications network by storing business data in a table separate from transaction data.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The present invention is described in detail below with reference to the attached drawing figures, wherein:
FIG. 1 depicts an exemplary operating environment suitable for practicing an embodiment of the present invention;
FIGS. 2 and 3 are block diagrams that depict several inefficiencies of a data model that stores transaction data with business data in the same table and across multiple tables;
FIG. 4 is an exemplary data model according to an embodiment of the present invention that stores business data separate from transaction data; and
FIG. 5 is an exemplary flow diagram that illustrates a method for facilitating telecommunications network configuration-transaction processing, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a method and data model that enables an audit trail to be maintained of configuration transaction requests as they progress through a communications network. The present invention will be better understood from the detailed description provided below and from the accompanying drawings of various embodiments of the invention. The detailed description and drawings, however, should not be read to limit the invention to the specific embodiments. Rather, these specifics are provided for explanatory purposes that help the invention to be better understood.
Specific hardware devices, programming languages, components, processes, and numerous details including operating environments and the like are set forth to provide a thorough understanding of the present invention. In other instances, structures, devices, and processes are shown in block-diagram form, rather than in detail, to avoid obscuring the present invention. But an ordinary-skilled artisan would understand that the present invention may be practiced without these specific details. Computer systems, servers, work stations, and other machines may be connected to one another across a communication medium including, for example, a network or networks.
Throughout the description of the present invention, several acronyms and shorthand notations are used to aid the understanding of certain concepts pertaining to the associated system and services. These acronyms and shorthand notations are solely intended for the purpose of providing an easy methodology of communicating the ideas expressed herein and are in no way meant to limit the scope of the present invention. The following is a list of these acronyms:
AT
Access Tandem
CLLI
Common Language Location Identification
EO
End Office
NPA
Numbering Plan Area (Area Code)
NXX
Prefix - first three digits of telephone number after NPA
POP
Point Of Presence
POP CLLI
CLLI that identifies a point of presence
Further, various technical terms are used throughout this description. A definition of such terms can be found in Newton's Telecom Dictionary by H. Newton, 19th Edition (2003). These definitions are intended to provide a clearer understanding of the ideas disclosed herein but are in no way intended to limit the scope of the present invention. The definitions and terms should be interpreted broadly and liberally to the extent allowed by the meaning of the words offered in the above-cited reference.
As one skilled in the art will appreciate, the present invention may be embodied as, among other things: a method, system, or computer-program product. Accordingly, the present invention may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware. In a preferred embodiment, the present invention takes the form of a computer-program product that includes computer-useable instructions embodied on one or more computer-readable media.
Computer-readable media include both volatile and nonvolatile media, removable and nonremovable media, and contemplates media readable by a database, a switch, and various other network devices. Network switches, routers, and related components are conventional in nature, as are means of communicating with the same. By way of example, and not limitation, computer-readable media comprise computer-storage media and communications media.
Computer-storage media, or machine-readable media, include media implemented in any method or technology for storing information. Examples of stored information include computer-useable instructions, data structures, program modules, and other data representations. Computer-storage media include, but are not limited to RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile discs (DVD), holographic media or other optical disc storage, magnetic cassettes, magnetic tape, magnetic disk storage, and other magnetic storage devices. These memory components can store data momentarily, temporarily, or permanently.
Communications media typically store computer-useable instructions—including data structures and program modules—in a modulated data signal. The term “modulated data signal” refers to a propagated signal that has one or more of its characteristics set or changed to encode information in the signal. An exemplary modulated data signal includes a carrier wave or other transport mechanism. Communications media include any information-delivery media. By way of example but not limitation, communications media include wired media, such as a wired network or direct-wired connection, and wireless media such as acoustic, infrared, radio, microwave, spread-spectrum, and other wireless media technologies. Combinations of the above are included within the scope of computer-readable media.
To help explain the invention without obscuring its functionality, a preferred embodiment will now be referenced in connection with a telecommunications network. FIG. 1 indicates an exemplary operating environment suitable for practicing the present invention and is referenced generally by the numeral 100 . Operating environment 100 should not be construed as a limitation of the present invention. Additional components that can be used in connection with the present invention are not shown so as to not obscure the present invention.
Exemplary operating environment 100 includes a request-audit table 110 and a transaction-processing system 112 . Transaction-processing 112 includes a request server 114 , a business server 116 , a network server 118 , and a communications server 120 . Transaction-processing system 112 is shown in block-diagram form with only a few exemplary components so as to not obscure the present invention. Those skilled in the art will appreciate that a transaction-processing system may include a litany of other components, which are contemplated within the scope of the present invention but not shown. Transaction-processing system 112 is coupled to one or more communications switches 122 .
The servers illustratively shown as components of transaction-processing system 112 may be known by other names but illustrate that a transaction request (“request”) 124 progresses through a processing system. Thus, the present invention should not be construed as a method or system limited to a request that progresses through the illustrative servers shown. Rather, FIG. 1 illustrates that a request 124 progresses through several transitional states toward completion.
In the simplified environment shown, request 124 is received by request server 114 . At a step 126 , one or more entries are made into request-audit table 110 , which will be explained in greater detail below. The table entries describe aspects of a transaction request related to its progression through a network. Exemplary entries include an indication that request 124 was received by request server 114 , that request server 114 is processing request 124 , that request server 114 has completed processing its portion of functionality associated with request 124 , or any other indication of a subprocessing step. Processing continues to business server 116 .
At a step 128 , request-audit table 110 is updated to reflect the progression of transaction request 124 . The updates of step 128 may include an indication that the transaction request has been received, is being processed, or has been completed by business server 116 . Processing continues onto network server 118 , which performs actions on request 124 and updates request-audit table 110 at a step 130 . In a final exemplary process, request 124 is sent to communications server 120 . At a step 132 , the different statuses associated with communication server 120 are updated in request-audit table 110 . When transaction request 124 is sent to one or more communications switches 122 , an entry can be made in a single table, such as request-audit table 110 , that the transaction has been processed and sent to the network. By updating only a single table, the method described with reference to FIG. 1 allows an audit trail to be developed, whereby problems that occur during the progression of request 124 can be more easily identified.
To further illustrate a portion of the benefits associated with the present invention, FIGS. 2 and 3 depict a set of tables that include both business data and transaction data. As used herein, “business data” refers to transaction-independent data (except for a transaction identifier) and “transaction data” refers to transaction-dependent data, or data that does not vary as a transaction processes through various components toward completion. Turning now to FIG. 2 , three instances of an NPA table are shown and referenced by numerals 210 , 212 , and 214 . The NPA table relates NPA data with transaction data. NPA table 210 includes four columns— 216 , 218 , 220 , and 222 —that respectively correspond to an NPA ID, an NPA type, a transaction ID, and a transaction-status identifier (transaction status). A single row 224 is shown that reflects an NPA ID of “913,” an NPA type of “domestic,” a transaction ID of “T1234,” and a transaction status of “request received at requester.” These fields are respectively shown by reference numerals 226 , 228 , 230 , and 232 . As can be seen, business data 234 is undesirably housed in table 224 along with transaction data 236 . Historically, when the status of a transaction's progression changed, old data was overwritten with new data.
Absent the present invention, when a transaction's status changed, the new status was merely updated from a previous status. Stored in a single field, the status identifier would be perpetually overwritten by new updates. In a specific, arbitrary example, after a request had been received from the requestor and the request progressed to being processed by business data, the transaction status of “request received at requestor” reflected in cell 232 would be replaced with a transaction status of “processing business data” as reflected in cell 232 A, which is the same cell as cell 232 but numerically distinguished for explanatory purposes.
Thus, table 212 reflects an updated transaction status that has overwritten a previous status identifier. Table 212 is the same table as table 210 but is denoted by a unique reference numeral to explain the present invention. To further illustrate at least one problem historically associated with storing business data 234 in the same table as transaction data 236 , table 214 reflects that a transaction status of “building switch command” in cell 232 B has overwritten the previous status identifier of “processing business data,” reflected in cell 232 A.
As can be seen by the simplified illustration of FIG. 2 , there is no way to retrieve any type of historical data or audit trail associated with the progression of a transaction request. Without an audit trail, no metrics can be gleaned and no performance benchmarks. Thus, if a user wished to track the time lapse between when a transaction request was received to when the processing of business data began, such data would not be available to a user.
Another problem associated with grouping business data with transaction data in the same table is that updating transaction-processing statuses involves updating multiple tables. This is because data must be unnecessarily duplicated across multiple tables. An example of these inefficiencies can be illustrated with reference to FIG. 3 .
Turning now to FIG. 3 , three instances of the same table are shown and referenced respectively by numerals 310 , 312 , and 314 . Table 310 includes a customer-identifier column 316 , a customer-data column 318 , a transaction-ID column 320 , and a transaction-status column 322 . Table 310 includes one row 324 having four cells referenced by numerals 326 , 328 , 330 , and 332 . Here, business data 334 (which includes customer ID 316 and customer data 318 ) is inefficiently stored in the same table as transaction data 336 (which includes transaction ID 320 and transaction status 322 ). Table 310 observed in connection with table 210 of FIG. 2 illustrates that the transaction ID and transaction status records are duplicated in two tables.
The transaction ID of “T1234” is stored both in cell 230 of table 210 and in cell 330 of table 310 . Similarly, the transaction-status identifier is stored both in cell 232 of table 210 and in cell 332 of table 310 . When the status of a transaction request changes, both tables must be updated. For example, when the transaction request's status transitions from “request received at requestor” to “processing business data,” then both tables 210 and 310 must be updated. Updating table 310 has historically been done by overwriting the data in cell 332 with new data, such as “processing business data” as reflected in cell 332 A, which is the same cell as cell 332 but referenced here with a unique numeral to ease description of the present invention.
When the transaction status changes to “building switch command,” tables 212 and 312 must both be updated as respectively reflected in tables 214 and 314 . The present invention provides a data structure whereby transaction data is stored separately from business data.
Turning now to FIG. 4 , an exemplary data model according to an embodiment of the present invention is shown with reference to two illustrative tables 410 and 412 that store business data while a third table 414 stores transaction data. A transaction identifier is included in table 410 , linking it to the transaction data of table 412 . Those skilled in the art would appreciate that additional transaction data is stored in tables 210 and 310 , but only the “transaction status” column was provided for clarity purposes. Table 410 now has no need to store all of such transaction data. Similarly, table 412 is a customer table that associates business data of a customer ID and other customer data with a single identifier, namely a transaction identifier, such as “transaction ID.”
The transaction-ID field of tables 410 and 412 is linked to a request-audit table 414 by a single field, the transaction ID field. The request-audit table includes a transaction-ID column 416 , a transaction-status column 418 , and a time-stamp column 420 . Request-audit table 414 includes a first row 422 , a second row 424 , a third row 426 , and a fourth row 428 . Each of these rows corresponds to a desired logable event and should not be construed as a limitation of the present invention. Any event that is desirous to log can be logged and tracked.
Rows 422 through 428 are exemplary rows that may, for example, be byproducts of the method in FIG. 1 . For instance, with reference to FIG. 1 , when request 124 was received at request server 114 , then step 126 can be associated with generating row 422 , which indicates that transaction “T1234” is in a status of “request received at requestor” and occurred at a time “12:32:56:09.” As processing continues to business server 116 , row 424 may be generated during step 128 . Instead of overwriting the old data, the present invention enters a new row, row 424 , to indicate a status transition to “processing business data.”
The data model of the present invention provides that only a single table, request-audit table 414 , needs to be updated rather than multiple tables as has historically been the case. That is, tables 410 and 412 do not need to be updated incident to a transaction-status change. Thus, when request 124 advances toward completion to network server 118 , then during step 130 , row 426 may be generated. Row 426 indicates that transaction ID “T1234” is associated with a status of “building switch command” at a time of “12:33:00:15.” Again, even though the status of the transaction at issue changed, tables 410 and 412 do not need to be modified. Moreover, adding row 426 (as opposed to overwriting old data) creates an audit trail.
In a final illustrative step, row 428 is created when the status of request 124 transitions to “update sent to network.” From table 414 , it is clear that an audit trail has been established that marks the progression of the transaction request. Although only four transaction-status updates are shown, any number of status updates can be logged in accordance with an embodiment of the invention. That is, if a carrier wishes to log any number of events, then this functionality is offered by the present invention. A carrier, or other user, may wish to log five, ten, fifty, or however many steps of a request transaction. Each can be logged, and an audit trail associated with those events can be easily created.
The time stamps in column 420 denote the time associated with each event, or step, of a request transaction. Having this audit trail available enables a user to establish benchmarks and to evaluate problems associated with a communications network. For instance, if there was a large time gap between when the request was received at the requester and when the business server 116 received request 124 , then a determination can be made that interim processes are not operating efficiently. A difference between any two or multiple time stamps can be used to identify inefficiencies.
The present invention also enables inefficiencies to be associated with individuals. For instance, if a transaction analyst was responsible for insuring that data be communicated from network server 118 to communication server 120 , but a consistent time gap consistently appears between when a request leaves network server 118 and when it reaches communication server 120 , then it can be reasonably inferred that the person in charge of the task at issue may need to be trained on how to route data more effectively. The person, code segment, or other mechanism responsible for routing a request from a first component to a second component can be trained or optimized to route data more efficiently when unacceptable time gaps are observed.
The data model of FIG. 4 also makes recovering from error transactions much easier than has historically been possible. The audit trail of request-audit table 414 allows an analyst to view a transaction progression from when it starts to when it faults and everything in between. Thus, no visibility is lost from when a first transaction status transition to a second transaction status. As shown in FIG. 4 , historical transaction data is maintained separately from the business data of tables 410 and 412 . This structure ensures that transaction statuses are not overwritten when new statuses arrive and it eliminates the problem of having redundant transaction data spread across multiple tables. No longer do multiple tables need to be accessed and information gathered about the transaction to determine, or attempt to determine, when a transaction entered into a fault status.
The tables shown in FIG. 4 are overly simplified so as to not obscure the present invention. But in practical applications, switch tables may include several tens of columns and thousands or hundreds of thousands of rows. Moreover, transaction data is often stored across several tables, not merely two. Also, table 414 indicates only two transaction data items: transaction status and transaction time stamp. But in practice, a transaction may be associated with several or even tens of columns of data rather than merely two.
An exemplary method for processing a switch transaction follows. A transaction request is received. User data is formatted by a business-side process and the transaction is associated with respect to business data. The information from the business data is placed into a transaction table to be communicated to one or more switches. A distributor then distributes the information to the appropriate switches. After the switches process their respective updates, switch responses are received. The information received from the switches is formatted into one or more response tables. Finally, the transaction is denoted as successful or not. Because of these steps and the way a configuration transaction, another name for request 124 , is processed, both the idea and implementation of a data structure that maintains business-type data separately from transaction-type data is nonobvious. Because a communications network grows over time, legacy systems have business data intimately entwined with transaction data. Separating transaction data from business data at the table level is a resource-intensive process that requires a paradigm shift, whereby a focus is placed on processing transactions rather than merely retrieving data.
Historically, systems were data centric where tables were wrappers around a resource such as a switch. The present invention is centered around transactions and tracking those transactions rather than mere data. Historically, the central focus and objective was to have a switch store certain data and then mirror that same data in local tables. Moreover, there was little focus on the status of a switch transaction as it progressed through various components. That is, a primary emphasis was placed on attaining a final status, but little emphasis was placed on monitoring the subprocesses that ripened into the final status. Transaction requests were viewed almost as afterthoughts as a means to arrive at a goal.
But the present invention stems from a realization that the journey is as important, if not more important, than the destination. The present invention reflects a more comprehensive view where the transaction itself is the center of focus. Emphasis is placed on how a transaction is processed. That is, observing the transaction yields an indication of desired data rather than merely focusing on switch data to mimic its contents into local tables.
Turning now to FIG. 5 , which is an exemplary method for facilitating telecommunications network configuration-transaction processing in a switch. In step 510 , the switch receives a network configuration transaction. The switch processes the configuration transaction and maintains a first table that stores transaction-independent data, in step 520 . Also, in step 530 , the switch maintains a second table that stores transaction-dependent data. In turn, a transaction identifier is utilized to link the first and second table, in step 540 . In step 550 , predefined substeps associated with the network configuration transaction update the second table having the transaction-dependent data.
As can be seen, the present invention and its equivalents are well-adapted to increasing the efficiency of a communications network. Many different arrangements of the various components depicted, as well as components not shown, are possible without departing from the spirit and scope of the present invention. Those skilled in the art will appreciate the litany of additional network components that can be used in connection with the present invention.
The present invention has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art that do not depart from its scope. Many alternative embodiments exist but are not included because of the nature of this invention. A skilled programmer may develop alternative means of implementing the aforementioned improvements without departing from the scope of the present invention.
It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the claims. Not all steps listed in the various figures need be carried out in the specific order described. Not all steps of the aforementioned flow diagrams are necessary steps. | A method and data structure for monitoring the progression of a configuration transaction through a communications network is provided. The method includes creating an audit trail associated with the switch-transaction progression, iteratively updating the audit trail incident to an occurrence of a designated transaction-processing substep without overwriting previously stored data, and processing the audit trail so that it is available for access via a user interface. Historical data tracking the configuration transaction's process is preserved rather than overwritten. |
FIELD OF INVENTION
The present invention relates to multiplexing and processing the payload of a multiplexed frame structure, such as a SONET frame stream.
BACKGROUND TO THE INVENTION
The Synchronous Optical Network (SONET) was created as the standard fiber optic transmission system for long-distance telephone and data communications. SONET is most commonly described as a high bit-rate fiber-optic-based transport method that provides the foundation for linking high-speed ATM (Asynchronous Transfer Mode) switches and multiplexers and providing users with B-ISDN (Broadband—Integrated Services Digital Network) compliant services. SONET has a very detailed architecture and also comprises a series of protocols to implement this architecture. As the architecture is quite complex, this document will only describe those portions of the protocols and frame structure which are useful for explanation purposes.
First, the SONET hierarchy consists of a number of levels, organized according to data transmission speed. Each level has an optical carrier (OC) and an electrical level transmission frame structure, termed the synchronous transport signal (STS). The notation OC-N refers to the n th level of the optical carrier. The counting units are the basic 51.84 Mbps bit rate of OC-1. OC-3, for example, has a bit rate of 155.52 Mbps which is derived from the 3 times multiplier of OC-1. The STS-N notation follows that of the OC-N. For example, an STS-3 frame is sent on an OC-3 fiber link at 155.52 Mbps. The payload, a term commonly referred to, is used to indicate user data within a SONET frame.
SONET physical layer devices are often required to handle multiplexed SONET frame formats. In these frame formats, several lower-rate SONET data streams are byte-multiplexed to construct a higher-rate SONET stream. For example, it is possible to combine four STS-48 SONET frame streams (each running at 2.488 Gb/s) to create a single STS-192 SONET stream at 9.952 Gb/s by byte-interleaving: each set of four consecutive bytes within the STS-192 stream is drawn from the four STS-48 streams, taken in turn. A similar process can be used to produce an STS-192 stream from sixteen STS-12 streams at 622.08 Mb/s, or from some combination of STS-48 and STS-12 streams, and so on.
The American National Standards Institute (ANSI) T1.105-1995 standard, titled “Synchronous Optical Network (SONET)—Basic Description including Multiplex Structure, Rates and Formats,” further elaborates on the SONET frame formats and the data rates previously mentioned.
Processing such multiplexed frame streams presents a particular challenge as the data rates increase. On the receive side of the physical layer device, it is necessary to split the higher-rate SONET stream apart into the individual sub-streams and then to process each sub-stream separately. A reverse problem occurs on the transmit side. Using the traditional approach of dedicating a processing element to each individual sub-stream can result in a significant amount of hardware overhead. For example, implementing a device to process all possible valid combinations of lower-rate channels within an STS-192 would require 277 individual payload processors (1×STS-192, 4×STS-48, 16×STS-12, 64×STS-3, and 192×STS-1). Also, at any one time many of these processors would be inactive. This approach therefore leads to significant hardware inefficiencies as well.
DESCRIPTION OF THE PRIOR ART
In the prior art, the U.S. Pat. No. 3,747,070, issued to Huttenhoff, discloses an apparatus to transfer digital data in parallel from one position in an input data word to a different position in a data word. Essentially, Huttenhoff teaches the utilization of cascaded stages to shift data in the input words. The cascaded stages were utilized to combine signal paths which are in parallel. Huttenhoff does not teach the optimization of these techniques to a higher-rate SONET stream, for example.
The U.S. Pat. No. 3,812,467, issued to Batcher, discloses a permutation network capable of handling multiple modes of data accessing while a particular system is in operation. The permutation network, taught by Batcher, both arranges the order of incoming data and shifts the data such that entire data fields may be shifted.
The U.S. Pat. No. 4,162,534, issued to Barnes, discloses an alignment network, or permutation network, for use with a parallel data system. The network provides a selectively direct data flow while concomitantly shifting or transposing the data flow.
Both the U.S. Pat. No. 3,812,467 and the U.S. Pat. No. 4,162,534 have laid the foundation for handling input data from multiple input streams.
In U.S. Pat. No. 4,309,754, issued to Dinwiddie Jr., a data interface mechanism which interfaces between input and output data buses of different data widths is disclosed. This mechanism requires a finite number of random access storage units and means to access data stored in the storage units. While the mechanism interfaces between those data buses, Dinwiddie does not address the processing of parallel input buses of variable data widths, particularly input data having a variable-sized payload portion.
In U.S. Pat. No. 5,016,011, issued to Hartley et al., a processing system for converting a parallel data stream into a serial data stream is disclosed. While Hartley teaches the conversion of a parallel input data stream, the multiplexing and conversion of multiple streams, and their respective payload information, is not taught.
An alternative solution in the prior art would be to use some form of time-sliced arrangement, whereby a small number (preferably one) of payload processors would be combined with some kind of dynamic context switching capability to create the effect of multiple different payload processors. Accordingly, a single time-sliced state machine with 48 contexts would be used to emulate a set of 48 separate state machines for processing the 48 STS-1 or 16 STS-3c sub-rate streams that can be packed into an STS-48 frame stream. This solution reduces the amount of hardware resources needed, as well as increases the flexibility and efficiency of the physical layer device.
A significant issue with the use of time-sliced state machines, however, is that this approach is difficult to adapt to the problem of handling variable multiplexing ratios. For example, it is difficult to design the time-sliced state machine mentioned above to handle some random combination of STS-3, STS-12 and STS-48 payloads that can be packed into an STS-192 frame, due to the varying nature of the bandwidth and the data bus widths involved in handling the different sub-streams. In addition, the sub-rate payloads may be placed at arbitrary locations within the multiplexed frame stream; as a result, a large number of combinations of widths and starting locations are possible, causing the design of the time-sliced processor to become extremely complex. Moreover, the time-sliced design is difficult to extend to higher and higher speeds (e.g., extending the data rate from STS-48 to STS-192 or even STS-768 is not simple).
The shortcomings of the known techniques lie primarily in their extension to higher speeds (OC-192 and above), along with higher degrees of channelization. While this problem has not to date been commonly encountered it will in the future become an issue as faster SONET rates (STS-192 and higher) have only recently begun to be used. The problem becomes significant only when these higher rates need to be processed. It is possible to use fairly ad-hoc, brute-force solutions at the lower speeds (STS-48 and below), however, these solutions are not suitable for higher speeds. At STS-192 rates, for example, the clock rate required for byte-by-byte processing is 1.25 GHz, rising to 5 GHz for STS-768; this is impracticable with readily available CMOS technology.
The design of a suitable data conversion network for accommodating the possible combinations of sub-rate payloads is further complicated by higher degrees of channelization. For example, a common technique used at low data rates is to employ an array of shift registers that is programmed to convert and multiplex the sub-rate payloads to and from the higher-rate frame stream. However, the utilization of arrays of shift registers is problematic at higher speeds and degrees of channelization, because the complexity and resource consumption of the network becomes very large when the width of the buses increases. For instance, a 16-byte TDM bus width would entail a 128-bit×128-bit array of shift registers and multiplexing logic, and would require significant added complexity in its design to support variable channelizations.
In a co-pending patent application, Multi-Stream Merge Network for Data Width Conversion and Multiplexing, U.S. Ser. No. 09/812,821, filed Mar. 21, 2001 (hereafter referred to as the “multi-stream merge network”) which is incorporated herein by reference, can instead be used to simplify the design of the data conversion network, as well as that of the time-sliced processor. The multi-stream merge network has the desirable property that multiple simultaneous independent streams of different widths can be supported within the same network by a simple configuration process. In addition, all of these disparate streams are converted to a simple, constant-width, repeating TDM data stream by the network.
In order to overcome the aforementioned shortcomings of the prior art, the present invention seeks to provide a data conversion network or arrangement, containing the multi-stream merge network coupled with a time-sliced processor which would alleviate the problems of handling variably multiplexed SONET payloads using a simple time-division multiplexing system.
SUMMARY OF THE INVENTION
The present invention provides a multiplexed payload system for processing data organized in any interleaved framing structure, preferably SONET. Along a receive path, the system consists of an input shift register, an input multi-stream merge network, a time-sliced processing unit, and a context memory. Similarly, along a transmit path, the system consists of an output shift register, an output multi-stream merge network, a time-sliced processing unit, and a context memory. The transmit path functions in an identical manner to the receive path but in the reverse direction. The multi-stream merge network, in either direction, converts between spatially separated input data streams of various configurable widths and time-division-multiplexed streams of constant width. The input shift register and the output shift register serve to accept a serial stream of bytes from the data receiver and convert them to a parallel stream of bytes presented to the input multi-stream merge network, or to accept a parallel stream of bytes from the output multi-stream merge network and convert them to a serial stream of bytes to the data transmitter, respectively. The context memory stores the processing contexts for sub-rate payload streams derived from the serial stream of bytes. A separate context memory location is assigned to each sub-rate payload stream that is received or transmitted. The time-sliced processing unit retrieves processing contexts from the context memory in a fixed sequence and uses the processing contexts to process data presented by the input multi-stream merge network, or generate data presented to the output multi-stream merge network.
The multiplexed payload processing system of the present invention seeks to achieve several criteria. The first criterion is the utilization of a single time-sliced payload processor to handle arbitrary combinations of sub-rate payloads. These combinations are multiplexed into a single frame stream; the only limitation on the sub-rate payloads is that they should be related to the overall frame rate by powers of 2; e.g., STS-3 rates or higher in the case of SONET. The second criterion is that the time-sliced processor should be independent of the rates and formats of the various sub-rate payloads. According to a third criterion, the system must accommodate any arbitrary multiplexing sequence (i.e., the assignment of time-slots in the higher-rate frame to sub-rate payloads cannot be constrained). A final criterion is that the system operation must follow a fixed and repetitive sequence, thereby permitting simple configuration and control structures.
The detailed description of the present invention assumes a SONET frame stream with an STS-48 frame rate together with a 16-byte datapath width. However, the present invention may be embodied in any legal higher-bandwidth SONET frame rate, without sacrificing the granularity of multiplexing. For example, it is obvious that supporting an STS-192 frame rate that contains sub-rate payloads at the STS-3c level may be done by increasing the datapath widths to 64 bytes rather than 16 bytes. The same datapath could also be used, for instance, to support an STS-768 frame rate at STS-12c granularity.
The time-sliced processing unit functions independently of the multiplexing granularity and complexity of the incoming SONET frame stream. It is only necessary for the time-sliced processing unit to be able to process a given time-slot of data within the time occupied by the time-slot. The multi-stream merge network is responsible for eliminating the need for the time-sliced processing unit to deal with byte interleaving or to handle data blocks from different payloads that may be present in the same data word. In addition, the sequence of time-slots presented to the time-sliced processing unit is fixed and regular. The time-sliced processing unit is thus greatly simplified.
Furthermore, the system is capable of high processing rates. As disclosed in the aforementioned co-pending patent application, U.S. Ser. No. 09/812,821, the input and output multi-stream merge networks are very regular, highly pipelined, and have extremely simple control logic; they can thus be designed and implemented to run at relatively high clock rates with respect to the capabilities of the underlying semiconductor technology. Finally, the time-sliced processing unit has been substantially simplified by the use of the multi-stream merge networks, and hence can be designed for high performance (approaching that of a non-time-sliced, dedicated, processing unit). Thus, the present invention is amenable to the processing of multiplexed STS-192 and STS-768 payloads, even when the granularity of multiplexing is relatively small.
In a first aspect, the present invention provides a multiplexed payload processing system comprising:
an input data conversion network including a multi-stream merge network, having means for receiving parallel streams of variable-width data which are spatially separated on an input data bus; means for converting said parallel streams of data of variable width into a time-division-multiplex (TDM) data stream of constant width; means for outputting said TDM data stream onto a TDM bus; and a time-sliced processing unit having means for receiving said TDM stream of data from said TDM bus; means for extracting payload information from said TDM stream of data; means for processing said payload information in a fixed repetitive manner; and means for outputting the results on to an output data bus.
In a second aspect, the present invention provides a method of demultiplexing and processing a payload along a receive path, including the steps of:
a) receiving a parallel stream of spatially-multiplexed, variable-width data from an input data bus; b) transferring said parallel stream of variable-width data to an input data conversion network utilizing a multi-stream merge network; c) converting said parallel stream of variable-width data into a fixed and repetitive time-division-multiplex (TDM) stream of constant-width data; d) extracting payload data from said TDM stream of constant-width data; e) providing a context memory; f) retrieving context information for each of said constant width-data from said context memory; g) processing said extracted payload data using said context information to generate result data; h) outputting said result data onto an output data bus; and i) updating the context information in said context memory.
The above aspects cover the functionality needed to perform the processing of received frame streams. It will be obvious to persons skilled in the art that the processing of transmit frame streams can be implemented by simply reversing the order of processing steps or functional blocks.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described with reference to the drawings, in which:
FIG. 1 is a block diagram illustrating a data conversion network (which contains a multi-stream merge network) coupled to a time-sliced payload processor unit according to the present invention;
FIG. 2 is a block diagram illustrating the components of the SONET transmission system according to a first embodiment of the present invention;
FIG. 3 is an illustration of a portion of a payload within a SONET frame processed according to the present invention;
FIG. 4 is an illustration of a shift register output, in blocks of 16 bytes, according to a second embodiment of the present invention;
FIG. 5 is an illustration of the 16-byte blocks received from the input register and converted by the multi-stream merge network to a repeating sequence of 16 time-slots according to the present invention; and
FIG. 6 is an illustration of the SONET transmission system utilizing an array of logical FIFOs in the transmit and receive datapaths according to a third embodiment of the present invention.
DETAILED DESCRIPTION
FIG. 1 illustrates a block diagram of the multiplexed SONET payload processing system 10 A in the receive path, and 10 B in the transmit path, according to the present invention. In the receive path, the SONET transmission system 10 A consists of a data conversion network 20 A coupled to a time-sliced payload processor unit 30 A. The function of the data conversion network 20 A is to accept byte-interleaved SONET frames 25 and transform them to a time-division-multiplexed (TDM) data representation on a TDM bus 40 A. The SONET frames 25 may be derived from any combination of sub-rate payloads. The TDM representation selected enables the time-sliced payload processor 30 A to process any combination of sub-rate payloads that have been multiplexed to create the SONET frames 25 . Finally, the payload processor 30 A produces an output data stream 50 . The use of the data conversion network 20 A is advantageous in that it removes the multiplexing complexity and presents a uniform and consistent data representation to the payload processor 30 A.
In FIG. 1 , the transmit path functions are reversed but otherwise function in an identical manner to the receive path. A multiplexed SONET payload processing system 10 B is illustrated in the transmit path. An input data stream 60 is received by the time-sliced payload processor 30 B for processing. The payload processor 30 B outputs the TDM data representation onto a TDM bus 40 B. The TDM data representation is received by the data conversion network 20 B. Finally, the data conversion network generates and outputs byte-interleaved SONET frames 75 .
For example, consider an STS-192 SONET payload that is created from four byte-interleaved STS- 48 sub-rate payloads. In the receive direction, each incoming STS-192 SONET frame 25 consists of sets of 4 bytes, each byte belonging to a different STS-48 sub-rate payload. Presenting such a stream directly to a payload processor would render the processor's task very complex. The straightforward approach of processing the payload data a byte at a time would require the payload processor 30 A to have to run at extremely high rates (processing byte-level data at 1.25 Ghz).
Alternatively, the payload processor could be designed to run at a lower clock rate, but only in conjunction with a complex and expensive shift register or memory system that would accumulate bytes from each sub-rate payload until there was sufficient data to occupy a wider datapath word. Both problems are eliminated according to the present invention. Thus, for example, if it was preferred to design an input time-sliced processor unit 150 that processed data in variable-sized blocks rather than fixed-size units (e.g., in the case of handling variable-sized packet information), it would be possible to use these logical FIFOs 610 A to accumulate data for the various sub-rate payloads prior to initiating processing for the payloads. The logical FIFOs 610 A can also be used to overcome constraints on the operation of the input time-sliced processing unit 150 , e.g., a limit on the spacing between consecutive words from the same channel, or a limit on the number of words that may be processed for a channel at a time. A similar capability can be obtained for the output time-sliced processor unit 180 with the use of logical FIFO buffers 610 B between it and the output merge unit 170 . The implementation of an array of logical FIFOs 610 A, 610 B between it and the output merge unit 170 . The implementation of an array of logical FIFOs 610 A, 610 B is well known to a person skilled in the art and as such will not be covered in more detail in this document.
According to the present invention, the data conversion network 20 A is used to separate the bytes belonging to the four different STS-48 sub-rate payloads and group consecutive bytes from each STS-48 payload together into words. The words in turn are output onto the TDM bus 40 A to the payload processor 30 A. The TDM data representation allows the payload processor 30 A to work on data from a single STS-48 payload at a time, and also to receive a full word of data (rather than a byte, or a partial word) to process at a given time. It should be mentioned that, according to the present invention, the word width may be set to any number of bytes that is a power of 2; hence the payload processor may be designed to run much slower than the byte-level data rate of the incoming frame stream. In the above example, a 16-byte datapath width would enable the payload processor to run at about 77 MHz, instead of the normal 1.25 GHz byte data rate of an STS-192 frame stream.
FIG. 2 illustrates the multiplexed SONET payload processing system in the receive path 100 A, and in the transmit path 100 B, according to an embodiment of the present invention. The system 100 A consists of a data conversion network 20 A and a payload processor 30 A of FIG. 1 . The data conversion network 20 A comprises an input multi-stream merge network 130 and an input shift register 140 . The payload processor 30 A consists of a time-sliced processing unit 150 in communication with context memory means means 160 . As in FIG. 1 , the data conversion network 20 A outputs a TDM sequence of data words onto a TDM bus 40 A.
It should be noted that the input and output multi-stream merge networks 130 , 170 utilized are discussed in the co-pending U.S. patent application Ser. No. 09/812,821. As such, it is assumed that the details of the multi-stream merge network are available to a person skilled in the art and need not be discussed in detail in this document.
The input shift register 140 , while not essential, is utilized when the received SONET information is presented in byte-serial form. The purpose of the input shift register 140 is to convert the byte-serial SONET data to a byte-parallel format. A standard shift register mechanism is used to convert the byte-wide data input to a word-wide data output, with the word width being selected to match that of the datapath. Note that the word width is constrained to be a power of 2, and is also dictated by the smallest sub-rate payload that must be processed by the system 10 A.
The input multi-stream merge network 130 accepts the word-wide inputs in a parallel form, either from the input shift register 140 , or directly from some external SONET receive logic. The multi-stream merge network 130 performs a transformation such that each sub-rate payload present within the multiplexed SONET frame at its input occupies one or more time-slots on the time-division-multiplexed bus 40 A at its output. The data produced by the input multi-stream merge network 130 is coherent and time-division-multiplexed in a regular pattern, and is related to the input data by a fixed and regular association. The number of time-slots occupied at the output by any given sub-rate payload is proportional to the bandwidth consumed by the sub-rate payload within the complete SONET frame. The word width of the input multi-stream merge network 130 is constrained to be a power of 2. This constraint applies to the output merge network 170 as well in the system 100 B.
The payload processing unit 30 A processes the contents of each time-slot on the TDM bus 40 A according to a pre-configured payload type, and consists of a time-sliced processing unit 150 and associated context memory means 160 . The time-sliced processing unit 150 accepts data from the TDM bus 40 A, extracts the actual payload from the data, and processes the payload information. The time-sliced processing unit 150 operates on each time-slot in turn, reading context information from the context memory means 160 prior to processing the time-slot and writing updated context information back to the context memory means 160 after the processing is complete.
The context memory means 160 supplies per-time-slot context information to the time-sliced processing units. It is assumed that the context memory means 160 is capable of fetching and supplying context for a different sub-rate payload on each time-slot. However, the context memory means 160 is not a requirement of the present invention. The use of FIFO buffers, illustrated in FIG. 6 , would further minimize the complexity of the payload processor 30 A, as the use of FIFO buffers 610 A eliminates the need for the payload processing unit 30 A to follow a fixed time-slot sequence.
In FIG. 2 , an output shift register 165 , an output multi-stream merge network 170 , an output time-sliced processing unit 180 and an associated context memory means 160 comprise the output, or transmit, side of the multiplexed SONET payload processing system 100 B. As already mentioned in relation to FIG. 1 , the output side functions in an identical manner to the input, or receive side, but in the reverse direction. According to the present invention, the time-sliced processing unit 180 and context memory means 190 work in conjunction to process and encapsulate the supplied data into sub-rate SONET payloads, and place them into pre-assigned time-slots on the output TDM bus 40 B. The output multi-stream merge network 170 and the output shift register 165 also work conjointly to transform the time-division-multiplexed data, presented on the bus 40 B, to a byte-interleaved arrangement of sub-rate payloads, in byte-serial form. It should be mentioned that the output shift register 165 is not required if the data are transmitted in byte-parallel form instead.
On he input side, data are fed into the input shift register 140 in byte-serial form by an external entity. (This external entity is expected to implement all required opto-electronic conversion, clock and data recovery, deserialization and SONET overhead processing). Input shift register 140 converts the byte-serial data stream to a byte-parallel data stream of the required width. This byte-parallel stream is then fed to the input multi-stream merge network 130 , which will extract and group the bytes associated with each individual sub-rate stream, perform any necessary buffering and rate matching functions, and then implement the pipelined sequence of merge operations required to produce a TDM data stream at its output.
Each time-slot on the time-division-multiplexed bus 40 A will contain a set of consecutive bytes from any one sub-rate payload; the coherency of the time-slots implies that data from different sub-rate payloads will not be mixed in the same time-slot, and also that the ordering of bytes within a time-slot will correspond to their serial ordering at the input. It is important to ensure that a SONET frame boundary never falls within the byte-parallel data stream presented to the input multi-stream merge network 130 , otherwise the input multi-stream merge network 130 will not function properly and the time-slots will not be coherent. If the input shift register 140 is used, this may be accomplished quite simply by properly synchronizing the input shift register 140 operation to the SONET frame, such that the shifting-in sequence begins with the first byte of the frame and ends on the last byte. If the input shift register 140 is omitted, then the external apparatus generating the byte-parallel data for the input multi-stream merge network 130 is responsible for ensuring this.
The time-sliced processing unit 150 will accept data within each time-slot of the TDM bus 40 A, retrieve the pre-assigned context associated with the given time-slot, and perform the necessary processing on the payload data. The processing required varies depending on the type of data being transported by the sub-rate payload with which the time-slot is associated. For example, asynchronous transfer mode (ATM) cell payloads encapsulated within a SONET synchronous payload envelope (SPE) require cell delineation, header error check (HEC) processing, idle/unassigned cell removal and cell payload descrambling. On the other hand, a Packet-over-SONET (POS) payload will require high-level data link control (HDLC) frame delineation, point-to-point protocol (PPP) and HDLC frame extraction, Frame Check Sequence (FCS) checking, flag destuffing, and payload descrambling functions. Other types of payloads will require correspondingly different operations. The output of the time-sliced processing unit 150 comprises the output of the SONET payload processor 30 A, and may be cell or packet information depending on the contents of the particular sub-rate payload being processed at any instant.
Payload processing typically requires state information (for example, ATM payload processing necessitates a partial HEC value, a byte count and some state flags); this state information is obtained from the context associated with that time-slot within the context memory means 160 . At the end of the processing for that time-slot, the context is updated and returned to the context memory means 160 . If the next time-slot corresponds to the same sub-rate payload, the updated context is fetched back into the time-sliced processing unit 150 , otherwise, a different context is fetched.
Any limitations on the rate at which context information can be fetched, or the order in which data may be presented (e.g., some time-sliced processors 150 cannot handle a situation where two consecutive time-slots contain data from the same channel) can be handled using a small bank of logical FIFO buffers interposed between the multi-stream merge network 130 and the time-sliced processor 150 , as will be described with reference to FIG. 6 .
On the transmit side 100 B, the reverse process is implemented. The time-sliced processing unit 180 requests data for the different sub-rate payloads in some fixed (and pre-configured) sequence. This data is then processed according to the type of payload: for ATM payloads, the functions performed include HEC generation, rate decoupling (insertion of idle/unassigned cells) and payload scrambling; while for packet-over-SONET (POS) payloads, it implements HDLC framing, FCS generation, flag stuffing and rate decoupling. As before, the context memory means 190 is used to hold intermediate context required during cell or frame processing, and is updated after each word of payload has been processed. The output of the time-sliced processing unit 180 feeds a TDM bus 40 B that drives the output multi-stream merge network 170 . Note that the arrangement of time-slots on the TDM bus 40 B corresponds exactly to the order in which sub-rate payloads are processed by the time-sliced processing unit 180 .
The output multi-stream merge network 170 performs the opposite function to the input multi-stream merge network 130 : it disassembles and redirects the data in the time-slots to produce, at its output, a byte-parallel data stream that reflects the arrangement of sub-rate payloads that are being multiplexed to form the final SONET frame stream. The output multi-stream merge network 170 is statically configured to perform this association between input time-slots and output byte lanes, and implements all the byte reordering and buffering functions that are required to accomplish this. Finally, the output shift register 165 can be used to transform the byte-parallel output from the output multi-stream merge network 170 to a byte-serial output usable by the SONET transmit functions (SONET overhead insertion, serialization and electrical/optical conversion).
FIG. 3 illustrates an example of the operation of the receive (input) side processing datapath. Shown in FIG. 3 , in simplified form, is the structure of an STS-48 SONET frame 300 that has been multiplexed from sub-rate payloads. The SONET Transport and Path overhead are not normally processed by the system and have therefore been excluded. The remainder of the STS-48 frame 300 consists of payload information. The STS-48 frame 300 is assumed to have been multiplexed from two separate STS-12c payloads (bytes labeled “A” and “B” in FIG. 3 ) and eight separate STS-3c payloads (bytes labeled “C”, “D”, “E”, “F”, “G”, “H”, “I” and “J” in FIG. 3 ). A small portion of the frame payload is shown.
The order of bytes shown represents the multiplexing process specified by SONET to combine lower-order payloads into higher-order payloads. In FIG. 3 , the multiplexing sequence repeats at 16-byte intervals, with 4 bytes from each of the STS-12c payloads “A” and “B” and 1 byte from each of the STS-3c payloads “C” through “J”, in each block of 16 bytes. This sequence is input, byte by byte, to the input shift register 140 of the input datapath. The datapath width is required to be 16 bytes; as noted previously, the word width of the datapath must be sufficient to accommodate the lowest-order sub-rate payload (in this example, an STS-3c within an STS-48, the ratio of bandwidths being 16:1, a 16-byte datapath is required).
FIG. 4 illustrates the conversion of a byte-serial stream to a byte-parallel stream by the input shift register 140 . As shown in FIG. 4 , the input shift register 140 orders the bytes in the sequence in which they were received, aligns to the first byte in each 16-byte block 400 , and transfers complete blocks of 16 bytes 400 to the input multi-stream merge network 130 . A new block of 16 bytes 400 is transferred on every cycle. The input multi-stream merge network 130 will accept the sequence of 16-byte blocks 400 generated by the input shift register 140 , and perform the requisite transformations for converting the input sequence into a time-division-multiplexed output sequence that can be processed by the time-sliced processing unit 150 . The transformations include byte reordering within each block—to group bytes from the same sub-rate payload into contiguous fields—and pipelined stream merging—to convert from a serial, variable-width spatially separate set of data streams to a time-multiplexed, constant-width data stream output on a common bus. Again, this transformation is detailed in co-pending U.S. patent application Ser. No. 09/812,821.
FIG. 5 illustrates the data processed by the multi-stream merge network 130 and output on the TDM bus 40 A. As shown in FIG. 5 , the series of 16-byte blocks is converted to a repeating sequence of 16 time-slots, 500 , 501 , 502 , . . . , 514 , 515 , with the number of time-slots assigned to any given sub-rate payload being proportional to the bandwidth required by that payload. Thus the first four time-slots 500 , 501 , 502 , 503 are filled with consecutive bytes from STS-12c payload “A”, the next four timeslots 504 , 505 , 506 , 507 with STS-12c payload “B”, and the remaining eight timeslots 508 , 509 , 510 , 511 , 512 , 513 , 514 , 515 are assigned to STS-3c payloads, in sequence, 508 , 509 , 510 , 511 , 512 , 513 , 514 , 515 . The time-slot construction is fixed (the sequence repeats without change) and coherent (each time-slot holds consecutive bytes from only one sub-rate payload). Each time-slot of 16-bytes is then passed to the time-sliced processing unit 150 . The time-sliced processing unit 150 processes all of the data for one time-slot in one cycle.
The functions performed by the conversion network 20 A, 20 B greatly simplify the task of the time-sliced processing units 150 , 180 . As there is no intermingling of bytes from sub-rate payloads, and all of the bytes are presented in consecutive order, it is only necessary for the processing units 150 , 180 to obtain the context corresponding to the sub-rate payload occupying each time-slot, perform the needed processing functions, and return an updated context to the context memory means 160 , 190 . In fact, the fixed and repeating sequence of time-slots implies that the context memory means 160 , 190 and time-sliced processing units 150 , 180 can be entirely decoupled in operation, whereby the context memory means 160 , 190 will fetch and store context information in a predetermined order and the time-sliced processing units 150 , 180 will simply accept the fetched context information and generate new context information to be stored, also in a predetermined order, without any hand-shaking or control signals between the two entities.
FIG. 6 illustrates an alternative processing system 600 A, 600 B of the present invention. The transmit and receive path systems 100 A, 100 B of FIG. 2 , are further augmented with a pair of FIFO buffers 610 A, 610 B, interposed into the time-division-multiplexed data streams presented to the input time-sliced processor unit 150 or generated by the output time-sliced processor unit 180 , respectively. The pair of FIFO buffers 610 A, 610 B output to and receive input from the payload processors 30 A, 30 B by means of the block-multiplexed buses 620 A, 620 B. These FIFO buffers 610 A, 620 A should be logically organized to provide a separate FIFO per sub-rate payload being multiplexed or demultiplexed. The provision of such FIFOs would further simplify the design of the time-sliced processor units 150 , 180 by decoupling their operation from the time-slot sequence created by the input and output multi-stream merge networks 130 , 170 , so that both the amount of data processed at a time as well as the order in which the data are processed may be varied independently of the constraints of the input and output multi-stream merge networks 130 , 170 .
Thus, for example, if it was preferred to design an input time-sliced processor unit 150 that processed data in variable-sized blocks rather than fixed-size units (e.g., in the case of handling variable-sized packet information), it would be possible to use these logical FIFOs 610 A to accumulate data for the various sub-rate payloads prior to initiating processing for the payloads. The logical FIFOs 610 A can also be used to overcome constraints on the operation of the input time-sliced processing unit 150 , e.g., a limit on the spacing between consecutive words from the same channel, or a limit on the number of words that may be processed for a channel at a time. A similar capability can be obtained for the output time-sliced processor unit 180 with the use of logical FIFO buffers 610 B between it and the output merge unit 170 . The implementation of an array of logical FIFOs 610 A, 610 B is well-known to a person skilled in the art and as such will not be covered in more detail in this document.
A person understanding the above-described invention may now conceive of alternative designs, using the principles described herein. All such designs which fall within the scope of the claims appended hereto are considered to be part of the present invention. | The present invention provides a multiplexed payload system for processing data organized in any interleaved framing structure, preferably SONET. Along a receive path, the system consists of an input shift register, an input multi-stream merge network, a time-sliced processing unit, and a context memory. Similarly, along a transmit path, the system consists of an output shift register, an output multi-stream merge network, a time-sliced processing unit, and a context memory. The transmit path functions in an identical manner to the receive path but in the reverse direction. The multi-stream merge network, in either direction, converts between spatially separated input data streams of various configurable widths and time-division-multiplexed streams of constant width. The input shift register and the output shift register serve to accept a serial stream of bytes from the data receiver and convert them to a parallel stream of bytes presented to the input multi-stream merge network, or to accept a parallel stream of bytes from the output multi-stream merge network and convert them to a serial stream of bytes to the data transmitter, respectively. The context memory stores the processing contexts for sub-rate payload streams derived from the serial stream of bytes. A separate context memory location is assigned to each sub-rate payload stream that is received or transmitted. The time-sliced processing unit retrieves processing contexts from the context memory in a fixed sequence and uses the processing contexts to process data presented by the input multi-stream merge network, or generate data presented to the output multi-stream merge network. |
This application is a continuation of application Ser. No. 07/397,406, filed Aug. 23, 1989, now abandoned which is a division of copending U.S. patent application Ser. No. 160,802, filed Feb. 26, 1988, now U.S. Pat. No. 4,880,851.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an aromatic composition and to a method for its manufacture; in particular, it relates to an aromatic composition that contains aromatic molecules that are encapsulated and/or clathrated, giving continuous aromaticity, and to a method for its manufacture.
2. Description of the Prior Art
In recent years, perfumes (aromatic substances) have been mixed with paints or printing ink so as to lend aromaticity to the coatings of said paints and printing inks. Usually, paints, printing inks, and the like are obtained by dissolving a resin component such as oil, natural resins, synthetic resins, etc., into a solvent, followed by the addition of pigments and dispersants to the solution. For example, to these paints and printing inks, perfumes are added to produce perfumed paint or ink. After the paint (or ink) is coated, the resulting coated layer is heated or dried naturally in the air so that the solvent volatilizes, resulting in the adherence of the resin component that contains perfume. In the method mentioned above, since the perfume is simply mixed with the paint or printing ink, transitory aromaticity can be obtained, but the perfume volatilizes together with the solvent, and long-term aromaticity cannot be maintained. In particular, if the coated layer is heated, the aromaticity is readily lost.
To solve this problem, the microencapsulation of perfumes has been tried. For example, by the coacervation method, molecules of a perfume are covered with a film of gelatin, polyvinyl alcohol (PVA), or the like, resulting in microencapsulated perfume particles with the diameter of 10-100 μm. Such microencapsulated perfumes are already commercially available. However, the perfume inside the microcapsule is sealed tight with the film of gelatin or PVA, and thus the scent is not released in the condition in which the microcapsules are manufactured. If the film of the capsule is physically destroyed, the scent is released for the first time. When the capsule is broken open, the perfume is released once, and the released perfume volatilizes in a short time. That is, after microcapsules are broken open, the aroma is not maintained for a long time.
SUMMARY OF THE INVENTION
The aromatic composition and the method for producing the same, which are provided by this invention, overcome the problems mentioned above of the conventional compositions and methods.
The aromatic composition of this invention comprises aromatic substances that are encapsulated and/or clathrated in a matrix of inorganic polymer produced from metal alkoxides.
Another aromatic composition of this invention comprises aromatic substances that are encapsulated and/or clathrated in a matrix of conjugated polymer produced from metal alkoxides and silane coupling agents.
Still another aromatic composition of this invention comprises aromatic substances that are encapsulated and/or clathrated in a matrix of conjugated polymer produced from metal alkoxides, organic monomers, and silane coupling agents.
The present invention provides a method for the production of an aromatic composition comprising aromatic substances that are encapsulated and/or clathrated in a matrix of inorganic polymers, which method comprises the steps of: adding an acid catalyst for sol-gel methods to a solution-containing water or a dispersion containing water of metal alkoxides and aromatic substances so as to cause the hydrolysis of said metal alkoxides; and adding a base catalyst for sol-gel methods to the reaction mixture so as to cause the polycondensation of the hydrolysate to form an inorganic polymer, said aromatic substances being encapsulated and/or clathrated in the matrix of said inorganic polymer thereby.
The present invention also provides a method for the production of an aromatic composition comprising aromatic substances that are encapsulated and/or clathrated in a matrix of conjugated polymers, which method comprises the steps of: adding an acid catalyst for sol-gel methods to a solution-containing water or a dispersion containing water of metal alkoxides, silane coupling agents, and aromatic substances so as to cause the hydrolysis of said metal alkoxides and said silane coupling agents; adding a base catalyst for sol-gel methods to the reaction mixture so as to cause the polycondensation of the hydrolysate to form a conjugate polymer, said aromatic substances being encapsulated and/or clathrated in the matrix of said conjugate polymer thereby.
The present invention also provides a method for the production of an aromatic composition comprising aromatic substances that are encapsulated and/or clathrated in a matrix of conjugated polymers, which method comprises the steps of: adding an acid catalyst for sol-gel methods to a solution-containing water or a dispersion containing water of metal alkoxides, silane coupling agents, and aromatic substances so as to cause the hydrolysis of said metal alkoxides and said silane coupling agents; adding organic monomers to the reaction mixture; adding a base catalyst for sol-gel methods to said reaction mixture, and immediately thereafter irradiation the reaction mixture with at least one of these two, ultraviolet light and an electron beam, so that the polycondensation of the hydrolysate occurs with the polymerization of said organic monomers and the hydrolysate of said silane coupling agents to form a conjugated polymer, said aromatic substances being encapsulated and/or clathrated in the matrix of said conjugated polymer thereby.
Thus, the invention described herein makes possible the objectives of (1) providing an aromatic composition in which the aromatic substances are encapsulated and/or clathrated in a matrix of inorganic of conjugated polymer, perfume molecules being released gradually over a long period of time; (2) providing an aromatic composition the aromaticity of which can be released slowly, which composition can be used in the production of, for example, furniture, clothing, cosmetics, building materials, and magnetic cards such as prepaid cards for use in telephoning by being mixed with printing ink, paint, printing materials for clothing, or the like; (3) providing a slow-release composition that has deodorant or insecticidal effects over a long period, which composition is produced by the encapsulation and/or clathration of deodorants, insecticides, or the like in the polymer mentioned above; and (4) providing a method for the production of superior aromatic compositions and slow-release compositions, both of which are mentioned above.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
On the basis of the inventor's knowledge that if it is possible to encapsulate or clathrate perfume molecules inside a porous polymer matrix, an aromatic composition with excellent slow release can be obtained, the inventor completed this invention with regard to an aromatic composition with the use of polymers and a method for producing the same.
The perfume used for the composition of this invention can be natural perfumes of animal origin or plant orgin, or synthetic perfumes. The perfume is used in the proportion of 1-300 parts by weight, and preferably 50-200 parts by weight, for every 100 parts by weight of the metal alkoxides mentioned below. If less than 1 part by weight is used, an aromatic composition of the desired aromaticity cannot be obtained. If more than 300 parts by weight is used, it is difficult to encapsulate the perfume in microcapsules or in polymer matrix.
The metal alkoxides used in the composition of this invention can be obtained by adding methanol, ethanol, isopropanol, and other well-known alcohols to metal oxides such as alumina, silica, titanium(IV) oxide, and zirconium(IV) oxide. For example, Si(OC 2 H 5 ) 4 , Al(O-iso-C 3 H 7 ) 3 , Ti(O-iso-C 3 H 7 ) 4 , Zr(O-t-C 4 H 9 ) 4 , Zr(O-n-C 4 H 9 ) 4 , Ca(OC 2 H 5 ) 2 , Fe(OC 2 H 5 ) 3 , V(O-iso-C 3 H 7 ) 4 , Sn(O-t-C 4 H 9 ) 4 , Li(OC 2 H 5 ), Be(OC 2 H 5 ) 3 , V(O-iso-C 3 H 7 ) 4 , P(OC 2 H 5 ) 3 , and P(OCH 3 ) 3 can be used.
The silane coupling agent used for the composition of this invention can be any of the well-known silane coupling agents, such as (γ-glycidoxypropyl)trimethoxysilane, (γ-glycidoxypropyl)methyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltrimethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltriacetoxysilane, (γ-methacryloxypropyl)trimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, mercaptopropylmethyldimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, octadecyldimethyl[3-(trimethoxysylil)propyl]ammoniumchloride, a mixture of aminosilanes, etc. For every 100 parts by weight of the metal alkoxide mentioned above, 300 parts by weight or less of the silane coupling agent can be used, with preferably 1-300 parts by weight, and still more preferable limits of 10-40 parts by weight. If more than 300 parts by weight is used, the polymer obtained is not very different from that obtained with less, and is expensive.
As organic monomers, there are acrylic acid, metharylic acid, dimethylformamide, acrylonitrile, stylene, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, etc. However, any vinyl-type monomer, and not just those listed here, can be used.
This kind of organic monomer is used within the limits of 200 parts by weight or less for every 100 parts by weight of the metal alkoxide mentioned above, and preferably 10-300 parts by weight, with still more preferable limits of 30-100 parts by weight.
The catalyst for sol-gel method (which is used to catalyze hydrolysis and polycondensation reactions for the metal alkoxides and silane coupling agents mentioned above) includes acids, their anhyrides, and organic bases. These organic bases are tertiary amines that are substantially insoluble in water and soluble in organic solvents.
As the acid used as a catalyst, it is possible to use mineral acid such as hydrochloric acid, sulfuric acid, nitric acid, etc. It is possible to obtain the same effects with the use of the anhydride of mineral acids, for example, with hydrogen chloride gas. Also, organic acids and their anhydrides can be used. For example, tartaric acid, phthalic acid, maleic acid, dodecylsuccinic acid, hexahydrophthalic acid, methyl endic acid, pyromellitic acid, benzophenonetetracarboxylic acid, dichlorosuccinic acid, chlorendic acid, phthalic anhydride, maleic anhydride, dodecylsuccinic anhydride, hexahydrophthalic anhydride, methyl endic anhydride, pyromellitic dianhydride, benzophenonetetracarboxylic anhydride, dichlorosuccinic anhydride, and chlorendic anhydride can be used. Per mole of the metal alkoxide, 0.01 mol or more of these acids, and preferably 0.01-0.5 mol, can be used. If the amount of the acid is less than 0.01 mol, the hydrolysis of the metal alkoxides does not proceed substantially.
As such tertiary amines used as a catalyst, N,N-dimethylbenzylamine, tributylamine, tri-n-propylamine, tripentylamine, tripropargylamine, N,N,N-trimethylethylenediamine, tri-n-hexylamine, etc., can be used. The tertiary amine can be used at equimolar amounts or in excess amounts of the acid mentioned above; preferably, it is used in amounts ranging from 0.01 to 0.06 mol per mole of the metal alkoxide. The amount of tertiary amine to be used can be chosen within the limits mentioned above with consideration of its degree of dissociation. If there is too little tertiary amine, than after the hydrolysis of the metal alkoxide, the rate of polycondensation is greatly slowed.
As the solvent that can be used in the method, in addition to the water used in the hydrolysis, it is possible to use an organic solvent. As the organic solvent, solvents that are miscible with water or solvents that can be partly dissolved in water can be used. These include, for example, methanol, ethanol, butanol, n-propanol, isopropanol, pentanol, hexanol, acetone, methyl ethyl ketone, and formamide.
The aromatic composition of this invention is manfactured by the following three main methods. In the first method, a polymer is made by the use of a metal alkoxide, and the perfume is trapped in a matrix of this polymer. In the second method, a polymer is made by the use of a metal alkoxide and a silane coupling agents, and the perfume is trapped in a matrix of this polymer. In the third method, a polymer is made by the use of a metal alkoxide, silane coupling agent, and organic monomer, and the perfume is trapped in a matrix of this polymer.
In the first method, for example, the metal alkoxide mentioned above is dissolved in the organic solvent mentioned above, such as, for example, alcohol. The concentration of the metal alkoxide is not set within any particular limits, but ordinarily, it is 500-600 g/l. Next, water is added to the metal alkoxide solution. The amount of water that is added is at the proportion of 1-30 moles per mole of the metal alkoxide. The water can be mixed beforehand with the alcohol mentioned above. To this solution of metal alkoxide (including water), the perfume mentioned above is added to obtain a solution or dispersion. The perfume can be added, for example, in the form of a solution in organic solvent or aqueous solution. To this, an acid (or its anhydride) catalyst for the sol-gel method mentioned above is added and the mixture is mixed at room temperature. The reaction is carried out at room temperature to prevent the volatilization of the perfume. With this treatment, hydrolysis is virtually complete. Into this reaction mixture, the tertiary amine catalyst (the other of the two forms of the catalyst) is added. When the tertiary amine is added, a polycondensation reaction proceeds and gelatin is completed within a relatively short time. The time taken for gelation or degree of gelation depends on the amount of water used and the amount of catalyst for the sol-gel method that is used. In general, it is possible to control the time of gelation from about 2 seconds to several dozens of minutes.
The gel mentioned above is constituted by an inorganic polymer formed by the hydrolysis and polycondensation of the metal alkoxide mentioned above. Perfume particles (i.e., fine granules of solid or liquid comprising molecules of perfume, and as the case may be, the organic solvent that containes the molecules of perfume) are trapped in a matrix of this polymer. More particularly, it is possible to encapsulate and/or clathrate particles of perfume in the following kind of form. In the reaction mentioned above, the metal alkoxide undergoes hydrolysis and polycondensation, including a cross-linking reaction, resulting in fine particles with a three-dimensional structure. When the particles with a three-dimensional structure is formed, the particles of perfume are trapped into the three-dimensional network constituted by the said structure. As a result, the particles of perfume are encapsulated in particles of polymer. These polymer particles gather in a number of clumps, and they further undergo polycondensation and cross-linking reactions to form a continuous three-dimensional matrix. The perfume particles are taken into the spaces inside, so as to be encapsulated or clathrated. When the solvent including alcohol produced by the polycondensation reaction is removed by volatilization from the three-dimensional matrix, as will be described below, the perfume remains in the porous matrix framework. It is known that the pores of the porous matrix mentioned above have an extremely small diameter (Science, Vol. 79, 192 (1986); Nikkei Science Inc.). For that reason, the perfume volatilizes gradually, which results in the fragrance continuing long-term.
In the second method, a silane coupling agent is used in addition to the metal alkoxide of the first method described above. For example, first, to a solution that contains metal alkoxide in alcohol and water, perfume, silane coupling agent, and a light-sensitizer, if needed, are added. As the light-sensitizer, diacetyl and the like can be used. The light-sensitizer accelerates the photocondensation reaction brought about by the ultraviolet radiation. Moreover, if needed, other monomers and polymers can be added. As such monomers, there are vinyl-type monomers, and as the polymers, there are copolymers and polymers polymerized from vinyl chloride, vinyl acetate, butadiene, etc. These monomers and polymers are added for the purpose of acceleration of the polymerization and copolymerization reactions described below, and for the purpose of the formation of a homogeneous and strong polymer.
To this mixture, as in the first method described above, a catalyst for the sol-gel methods is added, and the mixture is irradiated as needed by ultraviolet light and/or by an electron beam. The wavelength of the ultraviolet light is 250 nm or less. If this wavelength is more than 250 nm, the radical polymerization, cross-linking reaction, and polycondensation reaction mentioned below will probably not proceed sufficiently. The dose of radiation with an electron beam can be within the limits of 0.1-50 megarads. The amount of energy is preferably 150-200 kV. If less than 0.1 megarad is used, the radical polymerization, cross-linking reaction, and polycondensation reaction mentioned below will probably not proceed sufficiently. There is no need for more than 50 megarads. The radiation equipment for the electron beam can be, for example, an area beam electronic radiation device such as the Curetron (Nisshin Denki Co.).
The metal alkoxide and silane coupling agent in the reaction mixture mentioned above are hydrolyzed, followed by the subsequent polycondensation reaction, which proceeds rapidly. Moreover, when the silane coupling agent contains, for example, an epoxy moiety, the acid and base catalyst mentioned above cause cleavage of the epoxy ring, and ring-opening polymerization occurs. When a reaction mixture is irradiated with ultraviolet light and/or an electron beam, radicals arise from vinyl groups, and these radicals cause the cross-linking reaction and radical polymerization (i.e., photopolymerization or electronbeam polymerization) of the organic portion of the silane coupling agent. When ultraviolet light is used for radiation, the radicals arise from the light-sensitizer. In addition to an electron beam and ultraviolet light, other kinds of radiation can be used.
In these ways, the hydrolysis and polycondensation of the metal alkoxide and the inorganic portion of the silane coupling agent are made to proceed rapidly. Radical polymerization (including cross-linking polymerization) of the organic portion of the silane coupling agent can also be made to proceed rapidly. The reactions mentioned above occur between the silane coupling agents, between the metal alkoxides, and/or between the silane coupling agent and the metal alkoxide. The inorganic portion of the silane coupling agent (i.e., the silica portion) is taken into the framework of inorganic polymer molecules produced from the hydrolysate of the metal alkoxide, or forms an inorganic polymer by polycondensation arising among the silane coupling agents. The organic portion of the silane coupling agent that is attached to the silicon atom forms a cross-linked moiety with an organic portion of the other silane coupling agent molecule.
The polymer formed in this way has an inorganic polymer portion formed from the hydrolysis and polycondensation of the metal alkoxide and the silane coupling agent and also an organic polymer portion formed by the polymerization of the polymerizable group (i.e., organic portion) of the silane coupling agent. In other words, the metal alkoxide and the silane coupling agent react to form a polymer in which the metal alkoxide and the silane coupling agent are bound on the molecular level (this can be thought of as a conjugated polymer with an organic portion and an inorganic portion). The reaction system containing the said polymer becomes a gel, as in the first method mentioned above. The conjugated polymer forms a matrix with a three-dimensional structure that is almost the same structure as in the first method, and the perfume particles that are present in the reaction system are encapsulated or clathrated in the polymer matrix almost in the same way as in the first method.
In the third method, in addition to the metal alkoxide and silane coupling agents used in the second method mentioned above, an organic monomer is used. For example, first, to a solution of metal alkoxide in water and alcohol, perfume and silane coupling agent are added. To the mixture, an acid catalyst for solgel methods is added so as to hydrolyze the metal alkoxide, followed by the addition of the organic monomer. When photocondensation is carried out by the use of ultraviolet light, a light-sensitizer such as diacetyl can be added. Furthermore, other monomers and polymers can be added as in the second method, if needed. To this mixture, a base catalyst for sol-gel methods is added, and the mixture is irradiated with ultraviolet light and/or an electron beam. The reaction that is brought about in this way is similar to the reaction in the second method, and polymerization of organic monomers by a radical reaction occurs. This polymerization can occur between molecules of the organic monomer, and also between molecules of the said organic monomer and the organic portion (e.g., the epoxy moiety, vinyl moiety, etc.) of the silane coupling agent. In this way, a conjugated polymer is produced that has more organic portions than those of the polymer of the second method, and that has a complicated cross-linked structure. The perfume particles are encapsulated and/or clathrated in the conjugated polymer matrix as in the first and second methods described above.
In general, as a catalyst for sol-gel methods, mineral acids are widely known, but if such catalysts are used in the third method, compared to the polymerization of organic monomers, the hydrolysis and polycondensation reactions of the metal alkoxides and silane coupling agent become extremely slow. As a result, a homogeneous conjugated polymer is not formed. On the contrary, in this invention, catalysts for sol-gel methods mentioned above that has been developed by the inventors are used, and the reaction is very much accelerated, so that an homogeneous conjugated polymer is formed.
When an electron beam and/or ultraviolet light is used for radical polymerization in the second and third methods described above, the reaction proceeds at low temperatures such as 20°-30° C. so that the perfume will not volatilize and be lost. With the composition obtained by the use of the first and second methods, when the solvent and the alcohol are removed from the reaction system (including the framework of the matrix), a porous polymer matrix including perfume particles can be obtained. For that reason, with this composition as well, the slow release of the perfume is very satisfactory. The conjugated polymer in the composition obtained by these methods includes an organic portion in the molecule, so the rate of film formation, mechanical strength, processability, and adhesion to various kinds of base materials are excellent. For that reason, by application to base materials such as wood, synthetic resin, metals, fabrics, non-woven cloth, etc. with a paint to which this composition is added, various kinds of products with aromaticity having excellent slow release properties and with excellent durability can be obtained.
In general, the reaction mixtures that contain perfume particles that are encapsulated or clathrated by the first, second, and third methods described above are gels. The reaction mixture may be a sol that contains fine polymer particles, and the sol may also be used for various purposes. When the gel is mashed, for example, it can be mixed with printing ink or paint to give ink or paint with aromaticity. Alternatively, the gel can be dried, to give a porous polymer that contains perfume, and this can be mixed with paints and the like. This kind of ink and paint can be applied to fabric goods, building materials, furniture, etc., or these articles can be soaked in it. It is also possible to include this in cosmetics. In place of the perfume, insecticides or deodorants can be encapsulated and/or clathrated to give them long-lasting effects. The various products on which the composition of this invention is used can maintain their aromaticity, insecticidal properties, or deodorant effects long-term.
EXAMPLE 1
______________________________________Components Amounts (molar ratio)______________________________________Ethyl silicate 25 g (1)Water 8.6 g (4)Ethanol 25 mlAldehyde-type perfume 25 gHydrochloric acid 0.129 g.sup.(a) (0.03)N,N-Dimethylbenzylamine 0.321 g (0.02)______________________________________ NOTE: .sup.(a) Calculated in terms of hydrogen chloride.
After the ethanol, ethyl silicate, and perfume were mixed, water and hydrochloric acid were added, and the mixture was stirred for several seconds. N,N-Dimethylbenzylamine was added, and the mixture was stirred for 50 seconds more to obtain a gel. Next, the resulting gel was mashed and then dispersed evenly in printing ink (which contained 255 g of urethane-acrylate polymer emulsion and 7.2 g of pigment.)
The aromatic ink composition obtained was applied on the surface of cotton cloth, and was found to have uniform aromaticity for 8 months. When printing ink that contained acrylate-polymer emulsion instead of the urethane-acrylate polymer emulsion was used, the same results were obtained.
EXAMPLE 2
______________________________________Components Amounts (molar ratio)______________________________________Ethyl silicate 25 g (1)Water 8.6 g (4)Ethanol 25 ml(γ-Glycidoxypropypl) 6 gtrimethoxysilane(Tore silicone SH6040)Aldehyde-type perfume 25 gHydrochloric acid 0.129 g.sup.(a) (0.03)N,N-Dimethylbenzylamine 0.162 g (0.01)______________________________________ NOTE: .sup.(a) Calculated in terms of hydrogen chloride.
Ethanol, ethyl silicate, perfume, silane coupling agent (Tore silicone SH 6040), and water were mixed, and then hydrochloric acid and N,N-dimethylbenzylamine was added in this order by the same method as in Example 1. The resulting gel was mashed and then mixed uniformly in an ethanol solution containing 90% of nylon 6/11. This mixture was applied to the surface of a sheet made of polyvinyl chloride so that it would be 20 μm thick after drying. The scent lasted for 2 months.
EXAMPLE 3
______________________________________Components Amounts (molar ratio)______________________________________Ethyl silicate 25 g (1)Water 4.3 g (2)Isopropyl alcohol 20 mlAcetone 10 ml(γ-Glycidoxypropypl) 7 gtrimethoxysilane(Tore silicone SH6040)Ester-type perfume 20 mlHydrochloric acid 0.129 g.sup.(a) (0.03)N,N-Dimethylbenzylamine 0.162 g (0.01)______________________________________ NOTE: .sup.(a) Calculated in terms of hydrogen chloride.
In place of ethanol, isopropyl alcohol was used, and a reaction was carried out as in Example 2. The resulting gel was mashed and then mixed with acetone. Cloth (100% cotton broadcloth) was soaked in this mixture, removed, and then dried. The amount of mixture that remained on the cloth per unit area after drying was 13.8 g/m 2 . This aromatic cloth remained scented for 6 months.
EXAMPLE 4
______________________________________Components Amounts (molar ratio)______________________________________Ethyl silicate 25 g (1)Water 4.3 g (2)Isopropyl alcohol 25 mlAcetone 12 ml(γ-Glycidoxypropypl) 6 gtrimethoxysilane(Tore silicone SH6040)Acrylonitrile 18.9 mlEster-type perfume 10 mlHydrochloric acid 0.129 g.sup.(a) (0.03)N,N-Dimethylbenzylamine 0.324 g (0.02)______________________________________ NOTE: .sup.(a) Calculated in terms of hydrogen chloride.
Isopropyl alcohol, ethyl silicate, perfume, silane coupling agent, acrylonitrile monomer and water were mixed, and to this, hydrochloric acid and N,N-dimethyl-benzylamine was added in that order by the same method used in Example 1. The gel that was produced was mashed and diluted with acetone. The mixture was coated on the surface of glass plate so that it would be 10 μm thick after drying. The scent lasted for 2 months.
EXAMPLE 5
______________________________________Components Amounts (molar ratio)______________________________________Ethyl silicate 25 g (1)Water 8.6 g (4)Ethanol 25 mlDeodorant 50 g(Fresh-Shuraimatsu;Shiraimatsu Inc.)Hydrochloric acid 0.129 g.sup.(a) (0.03)N,N-Dimethylbenzylamine 0.324 g (0.02)______________________________________ NOTE: .sup.(a) Calculated in terms of hydrogen chloride.
Ethyl silicate, ethanol, deodorant, and water were mixed, and then hydrochloric acid and N,N-dimethylbenzylamine were added in this order by the same method as in Example 1. The resulting gel was mashed and then applied on the internal surface of a plastic garbage container for use in kitchens. The deodorant effects were retained for 2 months.
It is understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the scope and spirit of this invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the description as set forth herein, but rather that the claims be construed as encompassing all the features of patentable novelty that reside in the present invention, including all features that would be treated as equivalents thereof by those skilled in the art to which this invention pertains. | Compositions having perfume substance encapsulated or clathrated within are prepared by acid hydrolysis of an aqueous mixture of perfume substance and an alkoxide selected from metal alkoxides, phosphorus alkoxides, and tetraethoxysilane, followed by base catalyzed polycondensation using as a base catalyst N,N-dimenthylbenzylamine, tributylamine, tri-N-propylamine, tri-pentylamine, tripropargylamine, N,N,N-trimethylethylenediamine, or tri-N-hexylamine. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to apparatus for the printing and labelling industry, and in particular relates to a new butt cutting apparatus for use with rotary presses.
2. Description of the Prior Art
Rotary butt cutters are widely used in the printing and label stock industry in connection with label stock that is supplied with pressure sensitive adhesive and is attached to a releasable liner. Butt cutters are used to cut through label stock without cutting through the releasable liner attached to such material. This task requires high precision as only slightly improper cut depth results in either the labels not separating from the matrix, or in the label separating from the matrix but remaining affixed to the liner. Either scenario will typically cause malfunctioning of most automatic labelling machines.
There are two main types of apparatus currently used for butt cutting. The most common type of equipment makes use of two cooperating rollers or anvils, one of which is the cutting anvil and the other is a roller anvil against which the cutting anvil bears as the stock is cut. The cutting anvil is provided as an engraved die. These engraved dies do offer the high degree of precision required in the butt cutting operation. The use of engraved dies however is extremely expensive as a different die is required for each configuration and size of label stock to be cut. This requires that a substantial investment in tooling be made as several different dies must b=kept available for different tasks. The dies are also susceptible to damage and wear. If even one cutting edge of the die is damaged the entire die must be discarded. In normal conditions a die will also wear and become dull and must be sharpened. Typically, a die can be sharpened two or three times and then it must be discarded. Thus, while providing the required degree of accuracy for the butt cutting process, engraved dies as a cutting means are extremely expensive as an initial investment and as an ongoing expense.
The other type of standard equipment used for butt cutting operations also employs two cooperating anvils, one as a cutting anvil and the other as a bearer anvil. The main difference in this type of equipment is that the cutting apparatus is not permanently affixed to the anvil as with the engraved dies, but is provided by blades which are removably secured onto the cutting anvil. Most typically, this type of equipment is standard sheeting (cutting) or perforating equipment which is adapted to be used for the butt cutting operation. Although most manufacturers of sheeting or perforating equipment do not recommend it for butt cutting purposes as it typically cannot generate the required precision, it is often used because it is much less expensive than having separate engraved dies for each different configuration of material that is to be cut. The cutting edge of the blades and the surface of the cooperating anvil normally rotate at the same speed, and the stock is cut as the blades move in and out of engagement with the anvil surface. It is desired that the stock be cut as cleanly and accurately as possible. In typical machines, there is a need to replace blades frequently as any blade damage or significant blade wear will result in improper depth cuts resulting in the label stock not being cut through or in the label stock and the backing both being cut through. As such, a substantial amount of time is spent replacing worn or damaged blades.
In conventional rotary butt cutting apparatus utilizing replaceable blades, blade replacement is a very time consuming operation. The blades are set into slots or grooves which are milled into the surface of the cutting anvil. The blades are secured into position in the grooves by an appropriate securing means, typically being set screws. As it is virtually impossible to machine the grooves in the anvil to the required precision, it is necessary to "shim" the blades to achieve correct depth adjustment. When changing a blade the new blade is again loosely set into place and the anvil rotated so that the precise depth adjustment can be made. Once the correct height of the blade has been determined the height of the blade is then maintained by placing the shims under the blade. The blade is then tightened into its final cutting position. As stated, these procedures are very time consuming and result in considerable down time for the presses.
The present invention is directed to overcoming these and other difficulties inherent in the prior art. In the present invention a cutting anvil is provided with a removable cutting apparatus, which does not contain grooves into which the blades are secured. The present invention utilizes a cutting anvil which has a precision ground outer diameter against which the blades are secured by means of block assemblies. The height of each blade is ensured to be identical by having the blades precision ground to the same height prior to their installation onto the cutting anvil. Blade replacement can therefore be accomplished in a much shorter time than in conventional apparatus, as the new blades are simply set against the cutting anvil and immediately secured into place. This results in less set up time in adjusting blade heights and accordingly in less down time in production.
The use of a removable cutting apparatus also eliminates the need to maintain an expensive set of engraved dies.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved rotary butt cutting apparatus having a removable cutting apparatus that permits quick and accurate blade replacement.
It is another object of the present invention to provide a butt cutting apparatus that provides high precision.
It is still another object of the present invention to provide a butt cutting apparatus that can operate at high speeds.
It is still another object of the present invention to provide a butt cutting apparatus that can be quickly and easily adapted to cut label stock having a variety of backing thicknesses.
Thus, in accordance with the present invention, there is provided an improved cutting anvil for use in butt cutting of stock having a precision ground outer diameter, against which cutting blades are releasably secured, the blades having been ground to an identical height.
Further features of the invention will be described or will become apparent in the course of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be more clearly understood, the preferred embodiment thereof will now described in detail by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view, partially exploded, of the cutting anvil, showing the relationship of the anvil, blades and blade securing means in accordance with one embodiment of the, present invention;
FIG. 2 is an end cross-sectional view of the cutting anvil of FIG. 1;
FIG. 3 is an end view showing the cooperation of the cutting anvil of FIG. 1 with the anvil roller and the relative position of the label stock therebetween;
FIG. 4 is a close-up cross-sectional view corresponding to FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, and in particular to FIG. 3, rotating anvil apparatus for butt cutting operations constructed in accordance with one embodiment of the present invention is indicated at 40. The rotating anvil apparatus 40 finds particular application in butt cutting self-adhesive label stock affixed to a releasable liner.
The rotating anvil apparatus 40 includes a cylindrical anvil roller 20 and a cutting roller 10. The cutting roller 10 can be placed below the anvil roller 20 or alternatively can be placed above the anvil roller 20 as shown in FIG. 3. Typically, the cutting and anvil rollers are vertically positioned relative to each other so that the longitudinal axes of the cutting roller 10 and the anvil roller 20 are positioned in the same normal vertical plane, although that is not essential. The label stock 1 or other material to be butt cut passe between the cutting and anvil rollers, fed by feed rollers 30.
The diameter of the body 6 of the cutting roller 10 is precision ground to a tolerance of +0.0002/0.0000 of an inch. It is also essential that the body 6 be machined so that it is almost perfectly concentric between centers. The material chosen for the body is industry standard tool steel which is chrome-hardened.
Referring now to FIG. 1, the body 6 is carried on a pair of upstanding frame members 11, termed bearers. These bearers 11 cooperate with similar bearers (not shown) on the anvil roller 20 so as to define a nip between the anvil and cutting rollers through which a continuous web of paper material or the like 1 passes prior to being butt cut.
The body 6 has a plurality of precision ground trapezoidal blocks releasably attached thereto. Alternate blocks are intended to remain in place semi-permanently, in which case they are referred to as fixed blocks 12. The intermediate blocks are intended to be periodically removed, e.g. for blade adjustment or replacement, in which case they are referred to as retaining blocks 16. Flats 8 are ground onto the outer surface of the body 6 under part of the fixed blocks, to provide a suitably flat surface to which the blocks may be secured.
Drive means (not shown) engage gear 15 on the cutting roller 10 and are operatively associated with the anvil roller 20 and the cutting roller 10 to effect predetermined synchronized rotation relative to each other in opposite rotational directions and in timed relation to the surface speed of the material 1 as it is fed into the nip between the anvil and the cutter rollers.
The total number of retaining blocks 16 in the embodiment as described and shown in FIG. 1 is ten. Each block is of identical dimensions, and they are spaced in an equidistant manner around the outer periphery of the body 6.
Each retaining block 16 in the embodiment illustrated is secured to the body 6 by appropriate securing means. The embodiment illustrated in FIG. 1 utilizes at least two machine bolts 17 which extend through appropriately dimensioned holes in each retaining block 16 and into suitable threaded bores in the body 6. Machine bolts 17 are of the Allen key type. Each retaining block typically extends nearly the entire distance between the bearers on the body 6.
Each fixed block 12 in the embodiment illustrated is also secured to the body 6 by means of cap screws 17. In the case of fixed blocks, three cap screws are used instead of two, so as to permit simple visual identification by the press operator. Fixed blocks 12 are also located in exact position on the outer periphery of the body 6 by two dowels 9 extending radially outwardly from the surface of the body 6. These dowels 9 line up with two jig-drilled dowel holes 7 located in the fixed blocks 12. Hence the positioning of the fixed blocks is crucial and once it is achieved in the original set up of the cutting roller 10, it is not altered. The exact positioning is used to ensure that the exact distance is maintained between butt cuts. Shims positioned underneath the fixed blocks can be used to adjust the distance between butt cuts if necessary.
Blades 18 can be secured in the manner described below, the number of blades being dependent upon the desired mode of operation of butt cutting and the desired spacing between cuts on the material 1. Blades 18 may be retained in the correct horizontal position against the retaining block 16 by optional retaining pins 22. Blades 18 then have at least two holes 24, each hole being slightly elongated in the vertical direction, so that the blades can register properly against the precisely located outer surface of the body 6. The retaining blocks 16 are provided with slots 14 to provide space to accommodate the pins.
FIG. 1 actually shows a fixed block 12 exploded from the apparatus. In actuality, the retaining blocks 16 on either side of the fixed block would have to be removed before the fixed block could be installed.
Blades 18 are normally made of suitable knife steel in flat strips bevelled and sharpened along one edge. The opposite edge of the blades 18 are ground by the operator so as to provide blades with a consistent and precise height. Blades 18 may be of the typical straight edge variety for straight butt cutting applications or may be of saw tooth or other shape for "perforated" butt cutting o other applications.
The retaining blocks 16 retain the blades by forcing them against the fixed blocks. It follows that there should be a slight gap between the bottom of the retaining blocks and the body 6, to allow the retaining blocks to be torqued into position to secure the blades, without "bottoming out" prior to sufficient retention force being achieved.
Blade replacement in the apparatus of the invention is extremely simple and accurate. To replace a worn or damaged blade, the operator first removes the cap screws 17 which secure the retaining block 16 to the body 6. The retaining block is then removed from the body. The blade 18 is then removed from the retaining pins 22 on the fixed block 12 and a new blade is put in place. The action of tightening the retaining blocks not only forces the blades against the fixed blocks, but also forces them down against the outer surface of the body 6. Since that outer surface is precisely located, and since the height of the blades is precise, the position of the cutting edge is also very precise. One explanation for this is that it is much easier to obtain precision of the external surface of the body than it is t obtain a groove a precise depth as required by the prior art.
This entire process takes only a fraction of the time that it previously took to accurately replace blades located in milled-slot type cutting anvils. It is also of course much simpler and less expensive than having to send an engraved die back to the engravers for resharpening or even having to order a new die if the die cannot be resharpened.
If minute adjustments in the height of the blades are desired, e.g. to adjust for different weight (thickness) of backing paper, the adjustments can be achieved very simply by using shim strips 20 as shown in FIG. 4. Because the flat area 8 beneath each fixed block does not cover the full radius of the fixed block, small gaps are left under each edge of the fixed blocks. The shim strips can be flexed as shown in dotted lines, and then snapped into position against the outer surface, extending into the gaps so that they are definitely beneath the blades.
It will be appreciated that the above description related to the preferred embodiment by way of example only. Many variations on the invention will be obvious to those knowledgeable in the field, and such obvious variations are within the scope of the invention as described and claimed, whether or not expressly described.
It should also be obvious that the invention could be used for other than butt cutting, e.g. for sheeting or perforating. These applications do not require quite the precision which butt cutting requires and for which the invention is particularly advantageous. However, the invention is nevertheless useful for such other applications, both for precision and for the ease with which blades may be changed. | A cutting anvil assembly for use in butt cutting applications typically used in connection with self-adhesive label stock. The cutting anvil is ground to a precise outer diameter against which cutting blades of a precise height are secured by means of trapezoidal blocks. Rapid and simple changes of cutting blades are accomplished by simply setting the blade in place against the anvil and securing the blades in place between alternately semi-permanent and removable blocks. Adjustments of cutting depth to accommodate stock with different weight backings are also accomplished quickly and easily by positioning shims beneath the blades. |
The use of fossil fuels for power generation and in the petrochemical industry is expected still to increase in the first decades of the next century. The demand for low-sulfur fossil fuels has been intensified by the increasing regulatory standards for reduced levels of sulfur-oxides in atmospheric emissions, by the decline of easily accessible sources of conventional and light crude oils, and by the high cost of physicochemical process of hydrodesulfurization (HDS). It can be estimated that in the next decades 30% of oil should be desulfurized.
The use of microorganisms for the biodesulfurization of high sulfur coals and oil has been proposed as an interesting alternative for the reduction of the organosulfur contentof fossil fuels [Monticello Finnerty, Ann. Rev. Microbiol. 39 (1985) 371.; Bhadra et al., Biotechnol. Adv. 5 (1987) 1.; Kilbane and Jackowski, Biotechnol. Bioeng. 40 (1992) 1107]. Selective sulfur removal has also been reported by a pathway involving the conversion of dibenzothiophene (DBT) to 2-hydroxybiphenyl (2-HBP) and sulfate, as in the case of Corynebacterium sp. [Omori et al., Appl. Environ. Microbiol. 49 (1992) 911.], Rhodococcus erythropolis [Izumi et al., Appl. Environ. Microbiol. 60 (1994) 223.; Ohshiro et al., Appl. Microbiol. Biotechnol. 44 (1995) 249.; Wang et al., Appl. Environ. Mircobiol. 62 (1996) 3066.; Wang and Krawiec, Appl. Environ. Mircobiol. 62 (1996) 1670.], and Rhodococcus sp. strain IGTS8 [Kilbane and Jackowski, Biotechnol. Bioeng. 40 (1992) 1107.; Kayser et al., J. Gen. Mircobiol. 139 (1993) 3123.]. Most of the microbial biodesulfurization studies have focused on the aerobic conversion of DBT, coal or fuels. Nevertheless, reductive desulfurization of fossil fuels is an idea proposed more than 25 years ago by Kurita et al. [Denis-Larose et al., Appl. Environ. Mircobiol. 63 (1997) 2915.]. Mixed cultures containing sulfate-reducing bacteria (SBR) desulfurized a variety of model compounds, including thiophenes, organosulfides and petroleum preparations [Köhler et al., Zentralb1. Mikrobiol. 139 (1984) 239.; Miller, Appl. Environ. Microbiol. 58 (1992) 2176.; Eckart et al., Zentralb1. Mikrobiol. 141 (1986) 291.]. Reductive desulfurization of DBT to form hydrogen sulfide and biphenyl has been achieved by several species of SRB that are able to grow using DBT as sole source of sulfur and sole electron acceptor [Kim et al., Biotechnol. Lett. 12 (1990) 761.; Kim et al., Fuel Process. Technol. 43 (1995) 87.]. Hydrogen gas is the normal source of reducing equivalent, however, electrochemically generated reducing equivalents can be incorporated into the normal electron transport system of SRB.
Microbial desulfurization of petroleum derivatives has two main problems: Microbial activity is carried out in aqueous phase and under mild conditions, thus a two phase system reactor with the intrinsic mass transfer limitations would be needed to metabolize the hydrophobic substrate. On the other hand, the microbial biocatalyst must have a broad substrate specificity for the various organosulfur compound present in oil.
These problems could be addressed by using broad specificity enzyes instead of whole microorganisms. Enzymes are able to perform catalytic reactions in organic solvents [Dordick, Enzyme Microb. Technol. 11 (1989) 194.], in which the mass transfer limitations are reduced. The solvent could be the fuel itself. Under anhydrous conditions or at very low water activity, enzymes are generally more thermostable, and reactions could be performed at temperatures higher than 100° C. [Mozhaev et al., FEBS Lett. 292 (1991) 159.]. Biocatalytic modification of complex mixtures from petroleum, such as asphaltenes, have been performed in organic solvents for removal of metals [Fedorak et al., Enzyme Microb. Technol. 15 (1993) 429.].
Therefore, it is desirable to develop a biotechnological process which will remove sulfur-containing compound from fossil fuels in one-phase and non-aqueous system.
SUMMARY OF THE INVENTION
The invention relates to a method of removing organosulfur compounds from a fossil fuel comprising two steps. First, the contact of a fossil fuel with a biocatalyst, comprising peroxidases and other hemoproteins, which under suitable conditions oxidizes thiophenes and organosulfides to their respective sulfoxides and sulfones, and a second step in which the oxidized compounds can be separated by a distillation process or an other physicochemical process. The preferred systems included non aqueous systems such as water-saturated fuel, fuel solutions in organic solvents or in other petroleum derivatives. The biocatalyst could be free or immobilized in a support. Preferred embodiments of the biocatalyst include chloroperoxidase from Caldariomyces fumago, type-c cytochromes, or other hemoproteins from animal, plant or microbial cells. In one preferred embodiment of the invention, the oxidized organosulfur compounds are separated from the fuel by distillation, resulting in a low sulfur content stream.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 comprises gas chromatograms of desulfurized diesel fuel that has been enriched with dibenzothiophene and treated in accordance with the present invention;
FIG. 2 comprises gas chromatograms of primary diesel fuel before and after treatment in accordance with the invention; and
FIG. 3 comprises microdistillation profiles of untreated and enzymatically treated diesel fuel.
DETAILED DESCRIPTION OF THE INVENTION
The invention is based upon the fact that enzymes that oxidize thiophenes and organosulfides in complex hydrocarbon mixtures and with the presence of organic solvents. organosulfides in complex hydrocarbon mixtures and with the presence of organic solvents. Several enzymes have the ability to oxidize pure or single solutions of thiophenes and organosulfur compounds in vitro; cytochromes P450 [Nastainzcyk et al., Eur. J. Biochem. 60 (1975) 615.; Fukushima et al., J. Biochem. 83 (1978) 1019.; Wantabe et al., Tetrahedron Lett. 21 (1980) 3685.; Wantabe et al., Tetrahedron Lett. 23 (1982) 533.; Takata, et al., Bull. Chem. Soc. Japan 56 (1983) 2300.; Mansuy et al., J. Am. Chem. Soc. 113 (1991) 7825.; Alvarez and Ortiz de Montellano, Biochemistry 31 (1992) 8315.], lignin peroxidase from the white rot fungus Phanerochaete chrysosporium [Scheiner et al., Appl. Environ. Mircobiol. 54 (1988) 1858.; Vazquez-Duhalt et al., Appl. Environ. Mircobiol. 60 (1994) 459.], lactoperoxidase [Doerge, Arch. Biochem. Biophys. 244 (1986) 678.; Doerge et al., Biochemistry 30 (1991) 8960.], chloroperoxidase from Caldariomyces fumago [Alvarez and Ortiz de Montellano, Biochemistry 31 (1992) 8315.; Scheiner et al., Appl. Environ. Mircobiol. 54 (1988) 1858.; Vazquez-Duhalt et al., Appl. Environ. Mircobiol. 60 (1994) 459.; Doerge et al., Biochemistry 30 (1991) 8960.; Kobayashi et al., Biochem. Biophys. Res. Comm. 135 (1986) 166.; Colonna et al., Tetrahedron: Asymmetry 3 (1992) 95.; Pasta et al., Biochim. Biophys. Acta 1209 (1994) 203.], and horseradish peroxidase [Alvarez and Ortiz de Montellano, Biochemistry 31 (1992) 8315; Doerge et al., Biochemistry 30 (1991) 8960.; Kobayashi et al., Biochem. Biophys. Res. Comm. 135 (1986) 166.; Doerge, Arch. Biochem. Biophys. 244 (1986) 678.]. Non enzymatic hemoproteins are also able to perform the DBT oxidation in vitro, such as hemoglobin [Alvarez and Ortiz de Montellano, Biochemistry 31 (1992) 8315.; Klyachko and Klibanov, Appl. Biochem. Biotechnol. 37 (1992) 53.; Ortiz-Leon et al., Biochem. Biophys. Res. Comm. 215 (1995) 968.], cytochrome c [Klyachko and Klibanov, Appl. Biochem. Biotechnol. 37 (1992) 53; Vazquez-Duhalt et al., Enzyme Microb. Technol. 15 (1993) 494.; Vazquez-Duhalt et al., Enzyme Microb. Technol. 15 (1993) 936.], and microperoxidase [Mashino et al., Tetrahedron Lett. 31 (1990) 3163; Colonna et al., Tetrahedron Lett. 35 (1994) 9103.]. All the proteins mentioned above are hemoproteins, and in all cases the product of the biocatalytic oxidations are the respective sulfoxides. This invention is related to the biocatalytic oxidation of organosulfar compounds in complex mixtures, such as crude oil or petroleum distillates.
Fossil fuels include petroleum, petroleum distillates fractions, coal-derived liquid fuels, oil, bitumens, tars and asphaltenes, and mixtures thereof, particularly petroleum and petroleum distillate fractions as well as synthetic fuels derived therefrom. Fossil fuels containing a particular high content of sulfur in organosulfur compounds, such as dibenzothiophene.
The biocatalyst of the claimed invention includes an enzyme or enzymes or proteins capable of the oxidation reaction on organosulfur compounds in hydrocarbon complex mixtures. The biocatalyst also include chemically and genetically modified proteins. The biocatalyst which can be used in the disclosed method oxidize organosulfides and thiophenic compounds which are present in the fuel thereby producing sulfoxides and sulfones (dioxides) and thereby resulting in sulfur compounds with increased boiling point, leaving at least a majority of the hydrocarbons in their original form. Examples of the biocatalyst include hemoproteins, such as chloroperoxidase (EC 1.11.1.10) from Caldariomyces fumago, lignin peroxidase (EC 1.11.1.-) and managnese peroxidase (EC 1.11.1.7) from ligniolytic fungi, and cytochrome c from animal, plant and microbial cells. Biocatalyst that are usefull in the present invention include one or more unmodified hemoproteins, which are proteins containing a heme prosthetic group, and chemically or genetically modified hemoproteins which carry out the desired reaction with or without the presence of any electron aceptor, oxidizing agent or cofactor. Biocatalyst include microbial lysates, cell-free extracts, cell extracts, fractions, subfractions or purified products comprising the proteins capable of carrying out the desired biocatalytic function.
In a preferred embodiment, nutrients and other additives may additionally be added including coenzymes, cofactors or coreactants of the cells or enznmes. Electron aceptors, such as hydrogen peroxide or other organic and inorganic peroxides are used in the reaction.
In one embodiment, the biocatalyst is immobilized, improving this stability and faciliting recovery of the biocatalyst. For example, non-viable microorganisms or purified hemoproteins can be immobilized by physical or chemical procedures on the surface of severals carriers such as membranes, filters, polymeric resins, inorganic material, plastics, glass particles, ceramic particles or other supports.
The reaction can be carried out in a medium containing the fossil fuel in an aqueous phase or preferably in an organic phase. Emulsions and microemulsions can be made according to methods known in the art. The reaction mixture can be constituted by only the fossil fuel, the enzymatic system and the electron acceptor, with or without addition of water or any non-aqueous solvent or surfactants, minimizing the amount of water introduced into the reaction mixture. The reaction medium is then maintained under temperature and pH conditions sufficient to bring about the oxidation of the organosulfur compounds.
For example, the reaction mixture can be incubated under effective conditions for a sufficient period of time to produce a fuel product in which most of organosulfur compounds, thiophenes and organic sulfides, are oxidized. According the biocatalyst used the range of temepratures can be from 5° C. to 150° C. and the range of pH can be from 3 to about 11.
After biocatalytic oxidation, oxidized organosulfur from the reaction mixture containing unafected hydrocarbons are separated preferably by distillation. Other physicochemical processes can be used for the separation of the oxidized organosulfur compounds from the main hydrocarbon mixture such as column chromatography, precipitation, complexation with a solid suport, or another that is or will became available in the art.
The process can be performed in a batch, semicontinuous or continuous methods alone or in a combination with one or more additional refining process. The reaction can be carried out in open or closed vessel.
The invention will now be described more specifically by the examples.
Exemplification
EXAMPLE 1
Preparation of Chloroperoxidase from Caldariomyces fumago
Caladaryomyces fumago, a non-sporulating high chloroperoxidase (CPO) producing strain is used and maintained on PDA (potato-dextrose agar medium) plates at 4° C. A 2 liters pelletized C. fumago culture [Carmichael and Pickard, Appl. Environ. Microbiol. 55 (1989) 17.] growm for 10 days is used to inoculate 48 liters of fructose-salts medium [Pickard, Can. J. Microbiol. 27 (1981) 1298]. The stirred tank fermenter is operated as an air-lift, using 50 rpm agitation. After 10 days at 27° C. the medium cantains more than 100 mg CPO/1 based on the specific activity of 1660 U/mg [Morris and Hager, J. Biol. Chem. 241 (1966) 1763.]. The CPO is essentially the only extracellular protein produced [Pickard et al., J. Ind. Microbiol. 7 (1991) 235.]. The mycelium id filtered through nylon mesh and the spent medium is frozen and thawed twice in 25-liters plastic buckets. Precipitated gel is removed by fitration and centrifugation, prior to concentration to 10% of the original volume using ultrafiltration sytem with a cutoff of 10,000 Da. Remaining pigment is precipited with polyethylen gylcol, and removed by centrifugation. The PEG solution is diluted, reconcentrated by ultrafiltration, and dialyzed against 20 mM phosphate buffer pH 5.0. Further purification is accomplished by exchange chromatography through DEAE cellulose using a gradient of 20 to 200 mM NaCl. The purification can be carried out also by gel exclusion chromatography or by ammonium sulfate precipitation.
EXAMPLE 2
Preparation of Chemically Modified Cytochrome C
Poly(ethylene)glycol-cytochrome c is obtained according Gaertner and Puigserver [Eur. J. Biochem. 181 (1981) 207] by using activated poly(ethylene)glycol with cyanuric chloride (MW 5,000) [Vazquez-Duhalt et al. Enzyme Microb. Technol. 14 (1992) 837]. Cytochrome C is dissolved in a 40 mM borate buffer pH 10 and five-fold excess of activated poly(ethylene)glycol in free amino group basis is added. The reaction mixture is keep at room temperature during 1 hour. The reaction mixture is dialyzed and concentrated on an Amicon ultrafiltration system with a 10,000 Da membrane.
Methylated PEG-cytochrome c is prepared by the alkylation of free carboxylic acid groups to form methyl esters. Lyophilized PEG-cytochrome C (6 mg) is dissolved in 2 ml of N′N-dimethylformamide and then 2 ml of trifluoride-methanol reagent (BF 3 -methanol) are added and the reaction mixture is held for 12 hours at room temperature. The reaction mixture is diluted to 40 ml with phosphate buffer pH 6.1 and filtered through a 0.45 μm nylon membrane. Filtrate is then dialyzed and concentrated on an Amicon ultrafiltration system with a 10,000 Da membrane.
EXAMPLE 3
Biocatalytic Oxidation of Single Thiophenes and Organosulfides
The enzymatic reaction mixture (1 ml) contained 20 mM sulfur compound and from 40 to 690 nM cytochrome C or from 2 to 30 nM of chloroperoxidase in 15% (v/v) acetonitrile in 60 mM phosphate buffer (pH 6.1 for cytochrome or pH 3.0 for chloroperoxidase). The acetonitrile or other organic solvent is required to dissolve the sulfur compound in the buffer system. The reactions are carried out at room temeprature and started by adding hydrogen peroxide or other peroxide. The progress of the reaction is monitored by HPLC analysis or by Gas Chromatography.
Various model sulfur compounds were tested, including sulfur heterocycles and sulfides. The kinetic constants found with each sulfur compound are shown in Table 1. The analysis of the reaction products by GC-MS showed, in all cases, a molecular ion corresponding with the molecular weight of the respective sufoxide.
TABLE 1
Kinetic constant for the oxidation of organosulfur compounds
with unmodified horse heart cytochrome c and hydrogen peroxide.
Organosulfur compound
k cat (min −1 )
Dibenzothiophene
4.31
Thianthrene
3.00
Diphenyl sulfide
1.79
Dibenzyl sulfide
1.59
Benzothiophene
0.95
3-Methylbenzothiophene
0.67
Benzo[b]naphtho[2,1-d]thiophene
0.65
EXAMPLE 4
Oxidation of Low-sulfur Diesel Oil Enriched with Dibenzothiophene
Desulfurized diesel oil (<0.05% of sulfur) is enriched with 10 g/l of DBT and treat with poly(ethylene)glycol-modified cytochrome c (PEG-Cyt) and hydrogen peroxide. As seen in FIG. 1, where FID—flame ionization detector (general detector); FPD—flame photometric detector (sulfur selective detector), the gas chromatogram shows that the DBT is transformed to DBT sulfoxide, while the hydrocarbons seem to be not affected. DBT sulfoxide is an unstable compound which may be oxidized to form DBT sulfone. Cytochrome c is a biocatalyst able to oxidize thiophenes and organosulfides [Vazquez-Duhalt et al Enzyme Microb. Technol. 15 (1993) 494] and has several advantages when compared with other hemoenzymes. It is active in a pH range from 2 to 11, has the hemo prosthetic group covalently bond, exhibiting activity at high concentrations of organic solvents, and is not expensive [Vazquez-Duhalt et al. Enzyme Microb. Technol. 15 (1993) 494; Vazquez-Duhalt et al Enzyme Microb. Technol. 15 (1993) 936.]. In addition, this biocatalyst can be modified by site-directed mutagenesis [E. Torres et al. Enzyme Microb. Technol. 17 (1995) 1014.] and by chemical modification [Tinoco and Vazquez-Duhalt. Enzyme Microb. Technol. 22 (1998) 8.] to improve both its catalytic activity and range of substrates. PEG-modified enzymes are soluble in organic solvents and their activity in organic solvents is increased because of the reduction of mass transfer limitations in the system [Vazquez-Duhalt et al. Enzyme Microb. Technol. 14 (1992) 837].
EXAMPLE 5
Oxidation of High-sulfur Diesel Oil
Straight-run diesel oil, obtained from primary distillation and containing 1.6% sulfur, is used for oxidation by PEG-Cyt. Using this authentic diesel oil, the modified cytochrome c is able to oxidize most of the organosulfur compounds it contained. The oxidation is detected by the increase of boiling point (retention time) of these compounds on the gas chromatogram monitored with a Flame Photometric Detector (FPD), which is a sulfur selective detector.
With the aim of increasing the biocatalytic oxidation of sulfur compounds, chloroperoxidase from the imperfect fungus Caldariomyces fumago can be used on primary diesel oil. FIG. 2 presents gas chromatograms of primary diesel fuel (a) before and (b) after biocatalytic treatment with chloroperoxidase from Caldariomyces fumago. FID and FPD have the same meaning as indicated above for FIG. 1 . FIG. 2 shows that most of the organosulfur compounds were significantly oxidized and a considerable increase of the boiling points of all the sulfur compounds was found.
EXAMPLE 6
Biocatalytic Oxidation in Systems Containing Organic Solvent and Low Water Concentration
Biocatalytic oxidation can be canried out in a solvent system constituted by the fossil fuel, a water-miscible organic solvent, and a low amount of water. Another reaction system can be a ternary mixture or microemulsion in which a water inmiscible organic solvent is dissolved in a mixture of polar organic solvent, with or without the presence of a surfactant, and low amount of water. These mixtures are able to form reverse micromicelles or micoemulsions which are considered as one phase systems and in which there is biocatalytic activity. The simplest reaction mixture can be the fossil fuel saturated by water.
EXAMPLE 7
Removal of the Oxidized Sulfur Compounds from the Fossil Fuel by Distillation
After biocatalytic oxidation of the fossil fuel a second process of separation of oxidized organosulfur compounds is envisaged. Because the boiling points of sulfur compounds are incersed after biocatlytic oxidation to sulfoxides, it is possible to remove them by a single distillation. Oxidized sulfur compounds can be removed by decreasing the final distillation point. When primary diesel fuel containing 1.6% sulfur is distilled in order to obtain a 100% distillation at a temperature 50° C. lower than the original fraction, it produces a diesel fuel containing 1.27% of sulfur and 83% of the original hydrocarbons. If this petroleum fraction is previously oxidized by chloroperoxidase and hydrogen peroxide, and distilled at the same conditions, the disilate shows a sulfur content of only 0.27%, and 71% of total hydrocarbons. Thus, a biocatalytic treatment of primary diesel oil with chloroperoxidase from Caldariomyces fumago, followed by a distillation is able to reduce the sulfur content by 80%.
Microdistillations are carried out according to the standard test for boiling range distribution of petroleum fractions by gas chromatography, ASTM D 2887-89. FIG. 3 illustrates microdistillation profiles of untreated and enzymatically treated primary diesel fuel. FID and FPD have the meanings indicated for FIGS. 1 and 2, and CPO is chloroperoxidase. Microdistillation of both treated and untreated diesel oils monitored by Flame Ionization Detector, FID and by Flame Photometric Detector, FPD shows that the hydrocarbon distillation profile monitored by FID (general detection) changes slightly after the biocatalytic treatment. On the other hand, the specific sulfur detector (FPD) shows a significant change of the distillation profile. The IR spectrum of oxidized diesel fuel showed the presence of two strong absorbance bands at 1385 and 1464 cm −1 indicating the presence of sulfoxides and sulfones.
EXAMPLE 8
Removal of Oxidized Sulfur Compounds from Fossil Fuels by Chromatography
Because the polarity of organosulfur compound is incresed after the biocatalytic oxidation, a chromatographic process can be envisaged to remove these compounds from the fossil fuel. Natural or sythetic supports, such as silica gel, alumina, other metal oxides, natural or sythetic polymers, and other supports containing active groups, can be used. | The invention relates to a method of removing thiophenic and organosulfide compounds from a fossil fuel comprising the steps of contacting the fossil fuel with hemoproteins, which oxidize the sulfur containing compounds to sulfoxides and sulfones in a reaction system containing organic solvent or not, and followed by a distillation step in which sulfoxides and sulfones are removed from the fuel. Preferred biocatalysts include hemoproteins such as chloroperoxidase from Caldariomyces fumago, and peroxidases and cytochromes from animal, plant or microbial cells. The hemoprotein biocatalyst can be contacted with the fossil fuel in free or immobilized forms. The reaction can be carried out in the presence of the fuel alone or with addition of any organic solvent. The biocatalytically oxidized fuel is then distilled in order to eliminate the heavy fraction which contains most of oxidized organosulfur compounds. The light distillate contains significantly lower concentrations of sulfur when compared with the starting fossil fuel. |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to formerly filed applications filed by the same inventors and assigned commonly with the present application for invention entitled “Photocollage Generation And Modification Using Image Recognition” filed on Nov. 25, 1998 as Docket No.: 78616; and “System And Method Of Constructing A Photoalbum” filed on Aug. 19, 1998 as Docket No.: 78616.
FIELD OF THE INVENTION
[0002] The invention relates generally to the field of photography, and in particular to photo collections. More specifically, the invention relates to generating photocollages automatically and providing for alteration of the automatically created photocollage.
BACKGROUND OF THE INVENTION
[0003] Photographs, videos, and memorabilia collections are very commonly used to maintain memories and events that form part of an individual's life. These collections serve to augment the human memory and enrich the process of sharing stories related to the memories. When organized, viewed and shared on a regular basis a collection of memory artifacts generates a large reward, enriching the lives of all involved. The nature of these collections is such that they grow steadily, event by event, year by year, and soon become large and difficult to manage. Collections of photos and memorabilia are considered one of the most important and valued possessions by most people. They are the first things that people think of when forced to flee their homes due to fire, flood or other natural disaster. These collections possess intrinsic, emotional value, even if they are never viewed, because the need to preserve a memory of life is strong and universal. Because of the relative importance of these memories to the persons involved, the prior art is replete with teachings that disclose organizational methods.
[0004] The most common manner of organizing these collections within the prior art is to place the photos, videos or memorabilia into either an album or a box. Common vinyl album pages provide the means to store and view between one and five standard sized photos per page. Creative people often spend hours carefully selecting and arranging photos, writing captions, clipping newspaper articles, and other memorabilia to create visual stories or scrapbooks. Once organized into groups or pages these photocollages greatly enhance a person's ability to remember and share the story surrounding the depicted events. These simple organization tools allow the collections to be easily viewed and also serves to protect the artifacts themselves. There are numerous types of albums and boxes available in the market today, ranging from simple vinyl sleeves to boxes manufactured from specialized materials designed to preserve the artifacts. Album vendors include Pioneer Photo Albums, Design Vinyl and Cason-Talens. Box vendors include Exposures. None of these prior art disclosures provide a means by which a photocollage of these memorable events can be easily constructed by persons to who these event means so much.
[0005] As used herein photocollage refers to a single page having a plurality of images, such as a page in a photo album, or a composite image having a number of images relating to a single theme such as a vacation, wedding, birthday party or the like. The concept of photocollage as used herein also includes the concept of a bound photo album having a plurality of pages, one or more of which is a photocollage.
[0006] Despite the fact that many people are engaged in collecting these memorable artifacts, few people have the free time available to invest on a regular basis to organize and maintain them. Before long, the amount of unorganized material becomes a significant psychological barrier to getting organized. Other barriers exist which prevent people from actively maintaining these memorabilia collections such as confidence in their process, access to the materials, or remembering the details about the event. Often, once people get started on this organizational task they find it rewarding and fun, but still a significant amount of work.
[0007] Many attempts have been made to provide tools for working with or organizing photo and memorabilia collections. Computer software programs such as Picture-It™, by Microsoft, or Creative Photo Albums™, by Dog Byte Development, allow people to work with digital versions of their photos and create digital versions of an album or print them on a home printer. Software products such as these require each photo or artifact exist in digital form before they can be used. Although these products increase the ability to change and enhance photos and scanned memorabilia they do not reduce the amount of work needed to organize collections or create visual stories. Other services such as Photo-Net™ by PictureVision™ will scan photographs in a high-quality format at the time of photo processing and provide a thumbnail image of the scanned images via the Internet. A customer, using these scanned images can create collections of photos which can be viewed on the Internet or have prints generated. Currently some of these services do not allow for the arrangement of several photos on a page and are limited to consumers who have a collection of digital images and a computer connected to the Internet and who are both computer and web literate.
[0008] It should be apparent from the foregoing discussion that there remains a need within the art for a method by which consumers can create photocollages and photo albums (or have them made for them) in a manner that is as simple as ordering prints.
SUMMARY OF THE INVENTION
[0009] The present invention addresses the shortcomings within the prior art and provides an improved method of generating photo albums from consumer photographs that requires a minimum amount of effort but yields a high-quality product and is reasonably priced.
[0010] The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a system and method for producing a photocollage from a plurality of images, comprising the steps of: a) obtaining a digital record for each of the plurality of images, each of the digital records having a unique identifier and storing the digital records in a database; b) automatically sorting the digital records using at least one date type to categorize each of the digital records according at least one predetermined criteria; c) employing means responsive to the sorting step to compose a photocollage from the digital records. The system then associates each of the images with at least one of the categories followed by a sorting step that arranges the images according to the categories. The system then employs the categories to automatically construct the photocollage from the stored images by generating a plurality of pages of the stored images.
[0011] These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.
ADVANTAGEOUS EFFECT OF THE INVENTION
[0012] The present invention has the following advantages: Allows the user to have (1) an easy method for creating professional looking photocollages, (2) duplication of photocollages, and (3) keeping photocollage files for later use.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] [0013]FIG. 1 is a block diagram illustrating the basic system elements used in practicing the present invention; and
[0014] [0014]FIG. 2 is a system diagram showing the collection steps that take place once a customer has delivered images to the system;
[0015] [0015]FIG. 3 is a flow diagram showing the active processing goal steps used by the system of the present invention;
[0016] [0016]FIG. 4 is a flow chart showing the steps performed by the present invention towards a story preparation based photocollage;
[0017] [0017]FIG. 5 is a flow chart showing the steps performed by the present invention towards preparation of a photocollage that allows alterations after automatic creation;
[0018] [0018]FIG. 6 is a flow chart showing the steps performed by the present invention; towards preparation of a photocollage that is in a digital file format that can be sent across the internet;
[0019] [0019]FIG. 7 is a flow chart showing the steps performed in the processing facility illustrated in FIG. 2;
[0020] [0020]FIG. 8 is a schematic diagram showing a sticker sheet of reduced resolution images to be used with the present invention;
[0021] [0021]FIG. 9 is a drawing showing some of the layout styles available for a page in a photocollage.
[0022] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures.
DETAILED DESCRIPTION OF THE INVENTION
[0023] An acceptable photo album or photocollage can be created automatically from customers' exposed film, negatives, or digital images.
[0024] Referring to FIG. 1, which is the method as envisioned by the present invention designed to automatically produce photocollages including albums 17 , CDs 15 and other image-based keepsakes 11 . The process of transforming the supplied image material into a photocollage is referred to as Story Preparation services. Story Preparation services applies the necessary amount of image understanding embodied in a collection of processing modules executed in a non-linear sequence to create a story representation of the images. In a preferred embodiment these processing modules include: collecting, sorting, culling, annotating, grouping, enhancing, associating and, composing. These steps can be performed in the order listed or they may be rearranged in different sequences depending upon the desired output product. The production of a particular photocollage product may include one, two or, more of the available steps. Which steps are used and in what sequence is determined by the system based upon the desired product. It is important to remember that the present invention envisions providing sufficient image understanding of the subject images with the ultimate goal of teaching the system to understand that there are pervasive themes that exist within various sets of images and recognizing these themes thereby creating an image story product, or photocollage.
[0025] As shown in FIG. 2, the collection step begins when a customer, having completed picture taking for one or more events delivers one or more exposed film strips or cartridges 10 , digital still camera memory cards 12 , photographic prints 6 or video camera media 8 to a processing facility 14 . At the time that the customer delivers the exposed film cartridge(s) to the processing facility the customer's identity is recorded and associated with the suite of film cartridges and other image sources. Alternatively the customer identity may be encoded on the film by exposing a machine-readable sequence of marks along the edge of the film or by using the magnetic coating on the Advanced Photo System film. The conventional film processing takes place with conventional correction of exposed photographs to balance color and brightness and contrast. The exposed film images are chemically processed 16 to generate an optical image. These optical images are then scanned 18 to produce a high-resolution digital file that is archived in a data store 20 . In general, to produce a high-resolution printed image of 8×10 inch size, a resolution of 1538×1024 pixels is required. Digital Still Camera images from Digital Still Camera memory cards that are delivered to the processing facility are digitally processed 22 to produce an equivalent digital image file of similar size and stored on the data store 20 . Analog video camera images on media 8 delivered to the processing facility are digitized and processed before storage on the data store 20 . At the conclusion of this step in the process there exists a collection of digital image files associated with a customer by means of a customer identification. This collection of digital image data, or pixel data 32 , is now available as a source of data for the Story Services processing modules. Data attached or associated with individual images or groups of images provided by the customer such as date, time, location, sound, camera identification, customer identification, exposure parameters, Advanced Photo System IX data, are all examples of meta-data. This meta-data 34 is stored on image store 20 and associated with the available pixel data 32 . In addition the customer selects the desired output product or product type from a listing of available choices. This selection may be indicated by the customer marking the photo processing bag 24 , verbally indicating the desired product to a clerk 26 or by input at a computer terminal or kiosk 28 . The order description 36 generated from any one of the indicated sources provided by the customer is stored on the system and is associated, by means of a customer identification, with an existing customer profile 30 in the data store 20 .
[0026] At the conclusion of the collection step the pixel data, meta-data, customer profile and order description are available as input data for the subsequent processing steps. These steps can be performed in the order listed or they may be rearranged in different sequences depending upon the desired output product. The production of a particular photocollage product may include one, two or, more of the available steps. Which steps are used and in what sequence is determined by the system based upon the desired product. Following the collection step but before subsequent processing steps are performed, the specific processing to be applied to the collected set of image material is determined in a process goal generation step 37 and embodied in a set of photocollage processing goals 38 . For each of the output products requested the system determines an optimum sequence of processing steps to be applied. The processing of the output product or products will follow this system determined processing sequence, unless the sequence is modified by one of the processing modules. The processing output for each module is stated as one or more processing step goals. The processing in each step uses the stated processing step goals to control the logic, rules, and parameters applied during the processing of the collected image material to satisfy the stated processing step goal or goals. In addition to accomplishing processing goals each processing step can also create goals for itself or future processing steps. New goals, which result from executing a particular processing step, reflect necessary adjustments of desired parameters because the original goal is impossible to achieve or the processing step may generate new goals for subsequent processing steps. The initial set of processing goals 38 is determined by retrieving a default processing description from a database of available products 40 maintained by the system. Once the initial set of processing goals is determined the photocollage processing is initiated by the system.
[0027] As described, the automatic processing of photocollages is carried out in processing modules employed to perform these image understanding and interpretation steps. Each processing module relies on data from a number of sources in order to satisfy the processing goal. Each processing module has access to five sources of data: pixel information contained in the individual images, meta-data attached to images or groups of images, the original product or service order description, the list of active processing goals maintained by the system and, a customer profile containing information about the customer. The pixel data 32 for each image provides each module with the opportunity to apply image processing and image understanding algorithms. The meta-data 34 as used herein refers to the information attached to the individual images and to groups of images will contain information about the image or group of images which originated at the time of capture or was generated in prior processing of the image or group of images. Date, time, location, sound, camera identification, customer identification, exposure parameters, Advanced Photo System IX data, are all examples of meta-data that are, in a preferred embodiment, be attached to the original input images. The original product or service order description 36 contains the specific product request from the customer and any notes that were captured in the ordering process. At any time in the processing of the image or group of images the system will have a list of active processing goals 38 . Active goals are the processing goals for each processing module, which have yet to be accomplished by the system. At the start of processing this list will include the specific product or products requested by the customer, along with the translation of these product goals into system and module goals. The customer profile includes both factual and uncertain information related to the customer. The factual data would include general items such as name, address, names and ages of individuals in the household, important dates, anniversaries, product preferences and purchase history. In addition factual data such as face recognition feature vectors of the immediate family and extended family, voice training sets, handwriting samples, would also be included in the customer profile database. Uncertain information would include processing goals recommended by processing modules from previous order processing, image understanding assertions about the contents of the image or groups of images which have not been verified or other unverified information or assertions. Information and data contained in the customer profile is updated with every order processed to reflect changes in order preferences, order history and update uncertain information. In order to supply the system with the necessary amount of image understanding required to arrange the images into set in accordance with themes relating to predetermined criteria that must be provided for the system to have the capability to identify attributes within the images. For example, in a preferred embodiment, if a customer requests a birthday photocollage the system will retrieve the default processing goals which indicate that the steps of collecting, sorting, culling, annotating, and composing will be involved in the processing of the requested product. In addition the processing goals for each of the modules will reflect the default attributes necessary to process a birthday product. In this example the sorting module processing goals will include a sort by date goal and a sort by content goal. The sort by date processing goal is further refined to sort the images that occur on or near a target list of dates which are determined from a list of known birthdays retrieved from the customer profile into the photocollage.
[0028] In a preferred embodiment each processing module performs processing on two distinct levels: objective and subjective. The objective processing deals with factual information about the images or groups of images or with data calculated deterministic algorithms. Examples of factual data include the size of the image, capture parameters, histograms, image transforms, etc. Commercially available software programs such as Adobe Photoshop® and Corel Draw® process images using objective data. Subjective processing deals with information that is uncertain or data is the result of non-deterministic algorithms. Often subjective results carry with them a confidence factor which allows subsequent processing steps to interpret the results. Usually subjective results occur when attempting to determine abstract information about an image or group of images. Examples of this type of the processing would be face detection, face recognition, facial expression determination, location determination, assertions, interpretations, etc. Commercially available software programs such as FaceIT© by Visionics Corp. process images to associate faces in images with names and other information. Some processing modules process only subjective information, others process only objective information and still others process both.
[0029] As shown in FIG. 3 the processing of a photocollage is directed by the system using the active processing goals 38 , 48 , and 49 . Because the processing goals are non-deterministic, vary by requested product and may be modified during the processing there exist a large number of possible processing sequences. The progression of processing applied to the collected image material is applied in sequential steps. Each step implements a single processing module that is intended to satisfy or partially satisfy an active processing goal. At each step in the process any one of the available processing modules (culling 62 , grouping 64 , enhancing 66 , annotating 68 , associating 70 , or composing 72 ) may be executed. At the conclusion of the processing of a particular step the active processing goals 38 that existed before the step processing are updated to reflect the changes in goals that resulted from the execution of the processing step 52 . These updated active processing goals 48 serve as the input processing goals for the subsequent processing step 53 . Each of the available processing modules will be described. In addition to the processing goals 38 , 48 , and 49 , the processing modules at each processing step have access to four sources of information: pixel data 32 contained in the individual images, metadata 34 attached to images or groups of images, the original product or service order description 36 and, a customer profile 30 containing information about the customer. This process can iterate as many times as necessary to complete the desired product objectives.
[0030] The processing of the collection of digital image material is reviewed to remove unwanted images. This step is called culling. Culling is performed on images that are deemed unwanted due to poor quality, or if there are several images that are similar in composition and only one is desired. To accomplish this culling process involves the computation of several image based metrics using the pixel data 32 . These metrics fall into two basic categories: technical quality measures and abstract feature metrics. The technical quality measures would involve calculations to assess the overall sharpness of the image, exposure quality, grain quality of the image. Algorithms used to calculate technical quality measures are common in the art, examples would include: “Estimation of Noise in Images: An Evaluation” by S. I. Olson in, 55 (4), 1993, pp. 319-323 and “Refined filtering of image noise using local statistics” by J. S. Lee in Computer Vision Graphics and Image Processing, 15, 1981, pp. 380-389.
[0031] Images are then given an overall rating of technical quality based on the technical quality metrics. The overall image quality metric is then compared to a threshold associated with the processing goal. Images whose quality rating falls below the threshold are flagged as unwanted. The specific threshold applied to a given image or set of images is parametrically determined using the processing goal 38 and the customer profile 30 as inputs. In addition to the determination of specific objective image features, abstract subjective image features are also calculated. These subjective measures of the image allow the module to cull unwanted or unnecessary images. A typical example of images which require culling occurs when several images in the group are similarly composed and contain nearly identical content such as a group photo which is repeated several times. In order to choose the best of this group of images the digital image is analyzed to determine a quality metric composed of both objective and subjective quality features. The basis for this subjective assessment would be the presence or absence of faces, the identification of the faces in the image, the number of faces present, if the eyes are open on each face, if the subject is smiling, or orientation of the face to the camera. Examples of algorithms used to determine subjective features of an image are described in Proceedings of the IEEE Computer Society conference on Computer Vision and Pattern Recognition, June 1997. These subjective features provide clues about the subjective quality of the image. The objective and subjective features calculated for each image are combined and the images are ranked according to the relative importance of each feature analyzed to the processing goal 38 and which matches the stored customer preferences 30 . The ranking, because it is partially based upon subjective information also carries a probability weighting factor. The combination of the ranking and the probability weighting factor is used to assert a decision about the quality of the image. This quality assertion is retained with the image as metadata 34 and is passed to the next processing step. In the grouping step images are grouped according to criteria derived from the analysis of the customer profile 30 , the active processing goals 38 and the requested product or service 36 . The goal of grouping images is to associate images that are a part of a common theme or story in the mind of the customer. Typical groupings derived from customer profiles 30 would be to associate images according to the preferred organization scheme of the customer. The attributes of typical organization schemes would include organizing by events such as birthday party, vacation, holiday, graduation, organizing by time, and organizing by people. Customer requested products 36 could also dictate grouping parameters in accordance with the product design. Examples of these grouping schemes include grouping by location in a theme park, by common life-cycle event such as graduation, by image content type such as outdoor, indoor, nature, person, group, etc. A variety of software algorithms exist which are applicable to grouping. One class of software algorithms operates on metadata 34 associated with the image where the grouping process is similar to searching a media database. Several commercial examples of media databases that allow searching are Picture Network Incorporated, Publishers Depot (www.publishersdepot.com). A second class of algorithms employed for this grouping process would include image processing algorithms which identify objects and feature sets within an image by way of the pixel information 32 . These objects could represent typical cultural icons such as birthday cakes, Christmas trees, graduation caps, wedding dresses, etc. An example of such algorithms is reported by J. Edwards and H. Murase, “Appearance Matching of Occluded Objects Using Course-to-fine Adaptive Masks” in Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition, June 1997, pp. 533-546. The Product Order Information 36 can also be used in this grouping by simply stating the event or location or person on which to base the final product. The Processing Goals 38 can also be used as a grouping tool where the specific products offered mandate a specific grouping.
[0032] The annotation step seeks to generate annotation that can be composed on the story product or photocollage. Annotation is designed to provide context information about the image or group of images and assist the customer in communicating the story surrounding the images. A very common form of annotation is text associated with each image and with a group of images which explains the “who, what, when, where, and why”. Such context information is generally derived from metadata 34 generated in previous processing steps, user profiles 30 or, image understanding algorithms applied in the annotation module. “Who” information may be determined using face recognition algorithms applied to the pixel data 32 tuned by the training data contained in the customer profile 30 . Using a commercial product such as “Facelt” by Visionics, a database of known faces can be retrieved from the customer profile 30 and used to guide the face recognition software. “What” information can be asserted by correlating date and time of the image capture available in the image metadata 34 with key dates contained in the customer profile 30 . In addition more “what” data can also be asserted by looking within the image 32 for specific cultural icons, derived from object recognition algorithms, such as birthday cakes, Christmas trees or, graduation robes. “When” information for annotation is easily determined using metadata 34 such as date and time recorded at the time of capture. “Where” information may be provided from the capture device integrated with GPS (Global Positioning System) technology and then added to the metadata 34 for the image or it can be guessed at using image understanding algorithms which correlate known location scenes with the image content from available images 32 . “Why” information is very difficult to determine without some input from the image owner via the product order information 36 . The annotation, once determined, can be rendered as text, graphics, images, video or sound and associated with the individual images or with the group of images in either a traditional photocollage or digital product.
[0033] The image enhancement module applies image processing to improve the image for the intended story based purpose. Two categories of image enhancement are considered for each image. Basic image enhancements are applied to all images, as necessary, would include: red-eye removal, brightness and contrast adjustment, color adjustment, and crop and zoom to improve composition. Image enhancements are applied directly to the pixel data 32 and recorded in the image metadata 34 from the images. A second category of image enhancement is applied to the images in order to enhance their use within a story context to communicate the emotion or to support the story theme as described in the processing goal 38 . For instance, selected images from a wedding story would be softened using a blur algorithm or the colors of an image could be made to match those found in a comic strip. The application of this type of enhancement processing is either specified in the product description 36 generated from the customer profile 30 . All of these operations are available in image editing software programs such as Adobe PhotoShop, with the exception of red-eye removal and red-eye removal can be accomplished via the Kodak Imaging Workstation and other software such as Picture-It from Microsoft.
[0034] Some product specifications will include a processing goal to associate external content that is relevant to the product and the image content. This associated content provides additional context and interest in the final rendered product. External content takes several forms including weather reports, newspaper headlines, stock photographs, advertisements, historical references, travel brochure copy, popular music clips, video segments, etc. In order to locate and find appropriate content for the image story/photocollage the metadata 34 attached to each image and image group and is interrogated to derive searchable topics or specific information located in the customer profile 30 . These search topics would focus on the when, where, what aspects of the image story. Once a series of potential search topics have been assembled they are formatted into queries and searches are performed on a variety of databases. The results of these content queries is then refined by applying priority rules from the product description database and customer preferences stored in the customer profile 30 . These types of searches are common in information databases such as Yahoo® on the internet (www.yahoo.com) or from Dialog corp. If there are items within the image that can be identified with specific events (such as a wedding or birthday) or if a person can be identified from imaging algorithms, the Pixel Information 32 is used to determining the types of additional content that are added. The Processing Goals 38 dictate the forms and types of associated content that is added. The Product Order Information 36 is also a source of information regarding the association of content by a special request on the form (such as a theme park or wedding motif).
[0035] The layout processing module places the image data, annotations, and associated content into an output ready format. This layout step must be repeated for each product that was requested by the customer and for each layout goal that was generated during the processing steps. The main task involved in the layout of a multi-page photocollage is the determination of which images are to be placed in specific locations on specific pages. In addition the external content which has been associated with the individual images or groups of images must be composited onto the page. The layout process may be accomplished in numerous ways. One means of performing this processing step is to employ a parametric photocollage description. This description specifies the general structure of the photocollage but is not sufficient, of itself, to specify a final photocollage product. The description file includes photocollage features such as number of sections, size and format of individual pages, maximum and minimum number of pages allowable, maximum and minimum number of customer images allowable per page, section descriptions, cover designs, location of allowable stock content, etc. By employing a photocollage description file a variety of tailored photocollage products may be designed incorporating features specific to the design goals. The layout step begins by reading the photocollage description file to initialize a layout algorithm. The layout algorithm then works page by page and section by section to apply specific layout rules guided by the values in the photocollage description file. A variety of page/section layout algorithms could be employed which embody different design philosophies for photocollage products. The final photocollage product can be rendered on a variety of output media types which would include paper, fabric, as a digital file or on any one of a number of digital media forms such as a CD. The Processing Goals 38 are used to determine the capabilities of the specific devices being used. Customer Profiles 30 are used to determine color preferences, layout preferences, and design considerations. Metadata 34 is used to determine the placement of associated content with specific images. In a preferred embodiment, the first cut version of the photocollage is rendered as a scaled replica of the final version. This scaled replica is also identified using a template ID in the form of a bar code.
[0036] [0036]FIG. 4 shows the system diagram for Story Preparation Services. Input to the system comes from Personal Computers 90 (using albuming software such as Microsoft Picture It, Family Base from Micro Dynamics or a myriad of others), an interactive kiosk, via the phone or over-the-counter order forms 84 , a retail outlet 82 with links to the system, or digitization services 80 specializing in converting analog material into digital information. The information needed to perform the story services is communicated via traditional means including mail, phone, modem, Internet or other on-line services. The components required by such as system include a digitization system for pictures, video and audio 104 , a storage facility 102 , an operator interface 96 , algorithms and software 98 for the analysis of the data and to provide the necessary steps to complete the product, and an output delivery system 100 for printing or other media.
[0037] [0037]FIG. 5 is a flow chart showing the steps performed by the present invention towards preparation of a photocollage that allows alterations after automatic creation. The automatic creation of a first cut version of a photocollage proceeds as described above. After the first cut version is complete, the album is reviewed by the customer to determine if any changes are desired. In a preferred embodiment the user is also supplied with a set of scaled image stickers and templates to be used to modify the first cut version of the photocollage. The sticker images are generated at the time of the original photocollage processing as described below. These stickers and templates are illustrated and described in FIGS. 7, 8 and 9 and the discussion related, thereto. A customer wishing to construct additional pages for a photocollage or to modify the page layout of the first cut version selects one or more images by peeling the sticker image from the sticker sheet 118 and placing it on the page layout form 160 as shown in FIG. 9. The page layout form 160 includes one or more scaled graphic depictions of the final page each comprising a unique page layout. In one embodiment each scaled page representation includes one or more graphic image boxes each of which is an allowable location to place a sticker. Different scale page layout representations depict the available album page layouts made available by the service. Normally this variety of page layout choices would include variety along the dimensions of: the number of images per page, the resulting size of the images on the final printed page, arrangements accommodating both portrait (vertical) and landscape (horizontal) captured original images, different final printed page sizes, provision for annotation text, different size original images including standard 35 mm, Advanced Photo System classic, HDTV and Panoramic images and, Digital Still Camera formats. The scale of the sticker images and the scale of the graphic image boxes on the page layout order form do not have to be the same. If the page layout form image box is larger than the sticker image the image is enlarged to fill the box when producing the final printed album page. If the page layout form image box is smaller than the sticker image the image is reduced to fill the box when producing the final printed album page. In this way a variety of final output sized images can be made available to the user without the need to produce multiple sizes of sticker images. The page layout sheet and cover sheet would have identifiers 164 on them so that the page type can be identified during the scanning process. Bar code or alphanumeric characters can be used for this identification.
[0038] Other means to alter the placement of images in the photocollage can also be used including the use of a marking means using an “X” over the image to indicate deletion and a circle around the image and an arrow showing where the image is being moved on the photocollage. Photocollage templates can also be modified by other means such as the selection via ID numbers representing layouts in a catalogue showing the layout choices. After alteration, the modified photocollage is brought or sent to a location, such as a retailer, to be scanned and printed in final form.
[0039] [0039]FIG. 6 is a flow chart showing the steps performed by the present invention; towards preparation of a photocollage that is in a digital file format that can be sent across the internet. The process is similar to that shown in FIG. 5 except that all steps are performed on a digital computer with images being transmitted as digital files. It is envisioned that any alterations, both for changing the images within a page and changing the templates describing the layout of the pages, are performed by employing traditional software methodologies like drag-and-drop or choosing from a list for replacement of images and templates. In this digital case, the information needed to convey the changes can be sent electronically to the retail site for printing of the final photocollage.
[0040] Scaled image stickers used by the consumer to correct the first cut version of the photocollage are generated by using the original high-resolution images archived in processing facility 14 as seen in FIG. 2. This archive of digital images would, in most cases, comprise a software database application and a large collection of optical or magnetic storage media. In order to allow for the future association of the high-resolution images with their corresponding reduced resolution thumbnail images, each image is assigned a unique identifier. There are a variety of means, known in the art, for the generation of this unique identification. One such means is disclosed in Townsend and Shaffer, U.S. Pat. No. 5,784,461, in which a combination of the customer identification information and the photofinishing location, equipment, and date and time are combined. Other means of unique identification could be employed so long as they provide a one-to-one association of a person to a single image. The assigned unique image identification is associated with both the high and reduced resolution versions of the image. The unique identifier embodiment can be any of either: embedded data contained within the pixels themselves, invisible ink, visible codes, histogram, color information, or the like. The reduced resolution images are further processed to generate a formatted array or sticker sheet 118 as seen in FIG. 8.
[0041] Referring to FIG. 8, the sticker sheet 118 also includes an alpha numeric human readable image identifier 119 which allows the user to locate the corresponding photographic print of the sticker sheet image. In addition a unique machine-readable image identification is also included in the printed sticker sheet. The machine readable image identification could take the form of a bar code, machine readable characters or any one of a number of data-encoding patterns. A preferred implementation this unique machine readable image identification is to embed it directly into the pixels of the thumbnail image using signal processing techniques. An example of such techniques can be seen in Daly et al. (U.S. patent application Ser. No. 08/565,804).
[0042] The method of embedding digital data in an image can be best considered in two stages; an encoding process and a decoding process. First, a multi-level data image is generated from digital data. The multi-level data image as described in detail below is an image having a constant background value and an array of spots on the background representing the digital data. The data image may be produced using digital image processing techniques, or may be produced optically for example by exposing spots on a photographic film. Next, the data image is convolved with an encoding carrier image to form a frequency dispersed data image. The encoding carrier image is preferably a rotationally symmetric, low amplitude, high frequency pattern employed to spatially disperse the data image to mask its visibility when added to the source image. Preferably the convolution is performed on a digital computer using a well known Fourier Transform method and digital versions of the data image and the encoding carrier image. The convolution may also be performed using a direct convolution algorithm on the digital computer. Alternatively, the convolution may be performed optically using well known optical convolution techniques and optical versions of the data image and the encoding carrier image. The frequency dispersed data image is then added to the source image to form a source image with embedded data. As described in more detail below, the addition may be performed either optically using traditional photographic processes, or digitally using a digital computer and digital versions of the source image and the frequency dispersed data image. If the addition is performed digitally, a hard copy version of the digital source image having embedded data may be produced using a digital printer such as a thermal, ink-jet, electrophotographic, or silver halide printer.
[0043] Once the generation of the final photocollage from the modified first cut version of the photocollage has been accepted or modified by the user the modified version is rendered into a final photocollage. These modified photocollage orders are scanned to generate a final version processing order. If the modified photocollage contains image stickers the photocollage processing identifies the original high resolution data by recovering the embedded digital identification data. The digital identification data is recovered from the source image having embedded data by first cross correlating the source image having embedded data with a decoding carrier image to produce a recovered data image. Preferably, the decoding carrier image is identical to the encoding carrier image and the cross correlation is performed by a digital computer on digital versions of the source image having embedded data and the decoding carrier image. If a hard copy of the source image having embedded data is used, the hard copy is first scanned as described in detail below to produce a digital version. Alternatively, the cross correlation may be performed using well known optical techniques and optical versions of the source image having embedded data and the decoding carrier image. Finally, the digital data is extracted from the recovered data image. Preferably, the digital data is extracted from a digital version of the recovered data image using a pattern recognition process in a digital computer. Alternative methods for encoding data within an image can be found in issued U.S. Pat. Nos.: 5,636,292; 5,128,525; 5,285,438; and 5,126,779 which can also be used with the present invention.
[0044] Referring again to FIG. 2, after scanning the modified first version photocollage and template forms the processing facility uses the embedded image identification to generate the list of images needed to generate the final photocollage. Using the list of images the processing facility 14 finds and retrieves the corresponding high resolution images that were previously stored in the image storage 24 which are associated with the unique image identification numbers that were supplied by the scanned layout sheets 160 . These high-resolution images are then assembled into a photocollage using a page description language or template following graphical rules. These graphical rules incorporate customer preferences such as size of the pages, background styles and colors, etc. In this page layout process it may be necessary to zoom and crop the images to optimize the layout or to match customer preferences.
[0045] [0045]FIG. 7 illustrates the process steps that are performed from developing photographs to generation of photocollages by the processing facility of FIG. 2. The customer brings in exposed film 142 or a memory card from a digital camera 143 containing images that are to be made into a photocollage. The photofinisher generates traditional prints 146 for the customer. In the case of film, the film is scanned 145 to create a digital image. Once acquired, the digital images are assigned a unique ID 149 and placed into digital storage 150 . A sticker sheet 118 and a first cut version of a photocollage is generated 148 and sent to customer for review and modification. The sticker sheet 118 , first cut version of the photocollage and the layout pages 160 can be sent to the customer along with their prints. If modifications to the first cut photocollage are desired the customer selects images from the sticker sheet 118 places them on the first cut photocollage or on new page layout sheets or cover sheets 160 as they wish 151 . They would also select the type of product 153 from a standard order form supplied with sticker sheet 118 . The customer then returns the modified first cut photocollage, new cover and layout sheets 160 to the retailer 155 where the pages are scanned with the cover and layout sheet scanner 126 to create a photocollage order. The photocollage order is processed to determine which images are to be used in the photocollage, the cover, the layout and the product type 157 . The unique identifiers from the reduced resolution images are then associated with the images stored in the online storage facility and these full scale images are retrieved 152 . The photocollage is then constructed and printed 154 and sent to the customer 156 .
[0046] Depending upon the method employed for rendering the image identification number within the sticker sheet a variety of image processing techniques would be employed. In the case of human readable image identification numbers optical character recognition software is employed that translates the scanned image of the characters to a digital number representation. In the case where the image identification was hidden within the pixels of the reduced resolution image, a reverse of the data embedding signal processing technique is employed. The images are processed to remove any rotation and scale variations introduced in the printing and scanning steps. The result of this processing is to generate a list of the identification numbers of the images which the customer desires to have placed into the photocollage.
[0047] The invention has been described with reference to a preferred embodiment However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention.
PARTS LIST
[0048] [0048] 6 photographic prints
[0049] [0049] 8 camera media
[0050] [0050] 10 cartridges
[0051] [0051] 11 keepsakes
[0052] [0052] 12 memory cards
[0053] [0053] 14 processing facility
[0054] [0054] 15 CDs
[0055] [0055] 17 albums
[0056] [0056] 20 data store
[0057] [0057] 22 digital processing
[0058] [0058] 24 processing bag
[0059] [0059] 28 kiosk
[0060] [0060] 32 pixel data
[0061] [0061] 34 meta-data
[0062] [0062] 36 order description
[0063] [0063] 37 goal generation
[0064] [0064] 38 processing goals
[0065] [0065] 40 products
[0066] [0066] 48 processing goals
[0067] [0067] 49 processing goals
[0068] [0068] 62 culling
[0069] [0069] 64 grouping
[0070] [0070] 66 enhancing
[0071] [0071] 68 annotating
[0072] [0072] 70 associating
[0073] [0073] 72 composing
[0074] [0074] 118 sticker sheets
[0075] [0075] 119 numeric identifier on stickers
[0076] [0076] 142 exposed film
[0077] [0077] 144 film processed
[0078] [0078] 145 film digitization
[0079] [0079] 146 prints returned
[0080] [0080] 148 materials for photocollages returned to customer
[0081] [0081] 149 unique ID
[0082] [0082] 150 digital storage
[0083] [0083] 151 image selection and placement
[0084] [0084] 152 high resolution image retrieval
[0085] [0085] 153 product decision
[0086] [0086] 154 photocollage printing
[0087] [0087] 155 return of materials
[0088] [0088] 156 finished product sent out
[0089] [0089] 157 layouts scanned
[0090] [0090] 160 page layout sheet
[0091] [0091] 162 cover layout sheet
[0092] [0092] 164 identifier for page layout sheet or cover sheet | A method and system for employing image recognition techniques to produce a photocollage from a plurality of images wherein the system obtains a digital record for each of the plurality of images, assigns each of the digital records a unique identifier and stories the digital records in a database; automatically sorts the digital records using at least one date type to categorize each of the digital records according at least one predetermined criteria; and generates a first draft of a photocollage from the digital records. The method and system provides for alterations of the first draft using either a sticker selected from a plurality of stickers which each have a unique identifier within a data base or a digital file format that allows drag and drop features of both the photocollage and alternative images to be placed within the photocollage. The system employs data types selected from pixel data; metadata; product order information; processing goal information; or customer profile to automatically sort data typically by culling or grouping to categorize according to either an event, a person, or chronologically. |
BACKGROUND
1. Field of the Invention
The present invention relates to techniques for conserving power usage in computer systems. More specifically, the present invention relates to a method and an apparatus for reducing power consumption in a processor by reducing voltage supplied to an instruction-processing portion of the processor, while maintaining voltage to other portions of the processor.
2. Related Art
Dramatic advances in integrated circuit technology have led to corresponding increases in processor clock speeds. Unfortunately, these increases in processor clock speeds have been accompanied by increased power consumption. Increased power consumption is undesirable, particularly in battery-operated devices such as laptop computers, for which there exists a limited supply of power. Any increase in power consumption decreases the battery life of the computing device.
Modern processors are typically fabricated using Complementary Metal Oxide Semiconductor (CMOS) circuits. CMOS circuits typically consume more power while the circuits are switching, and less power while the circuits are idle. Designers have taken advantage of this fact by reducing the frequency of (or halting) clock signals to certain portions of a processor when the processor is idle. Note that some portions of the processor must remain active, however. For example, a cache memory with its associated snoop circuitry will typically remain active, as well as interrupt circuitry and real-time clock circuitry.
Although reducing the frequency of (or halting) a system clock signal can reduce the dynamic power consumption of a processor, static power consumption is not significantly affected. This static power consumption is primarily caused by leakage currents through the CMOS devices. As integration densities of integrated circuits continue to increase, circuit devices are becoming progressively smaller. This tends to increase leakage currents, and thereby increases static power consumption. This increased static power consumption results in reduced battery life, and increases cooling system requirements for battery operated computing devices.
What is needed is a method and an apparatus that reduces static power consumption for a processor in a battery operated computing device.
SUMMARY
One embodiment of the present invention provides a system that facilitates reducing static power consumption of a processor. During operation, the system receives a signal indicating that instruction execution within the processor is to be temporarily halted. In response to this signal, the system halts an instruction-processing portion of the processor, and reduces the voltage supplied to the instruction-processing portion of the processor. Full voltage is maintained to a remaining portion of the processor, so that the remaining portion of the processor can continue to operate while the instruction-processing portion of the processor is in reduced power mode.
In one embodiment of the present invention, reducing the voltage supplied to the instruction-processing portion of the processor involves reducing the voltage to a minimum value that maintains state information within the instruction-processing portion of the processor.
In one embodiment of the present invention, reducing the voltage supplied to the instruction-processing portion of the processor involves reducing the voltage to zero.
In one embodiment of the present invention, the system saves state information from the instruction-processing portion of the processor prior to reducing the voltage supplied to the instruction-processing portion of the processor. This state information can either be saved in the remaining portion of the processor or to the main memory of the computer system.
In one embodiment of the present invention, upon receiving a wakeup signal, the system: restores full voltage to the instruction-processing portion of the processor; restores state information to the instruction-processing portion of the processor; and resumes processing of computer instructions.
In one embodiment of the present invention, maintaining full voltage to the remaining portion of the processor involves maintaining full voltage to a snoop-logic portion of the processor, so that the processor can continue to perform cache snooping operations while the instruction-processing portion of the processor is in the reduced power mode.
In one embodiment of the present invention, the system also reduces the voltage to a cache memory portion of the processor. In this embodiment, the system writes cache memory data to main memory prior to reducing the voltage.
In one embodiment of the present invention, the remaining portion of the processor includes a control portion of the processor containing interrupt circuitry and clock circuitry.
In one embodiment of the present invention, the remaining portion of the processor includes a cache memory portion of the processor.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1A illustrates different power areas within processor 102 in accordance with an embodiment of the present invention.
FIG. 1B illustrates alternate power areas within processor 102 in accordance with an embodiment of the present invention.
FIG. 2 is a flowchart illustrating the process of monitoring processor load and switching to power saving modes 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 invention, 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 invention. Thus, the present invention 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.
Processor 102
FIG. 1A illustrates different power areas within processor 102 in accordance with an embodiment of the present invention. Processor 102 is divided into a core power area 126 , and a non-core power area 124 . Core power area 126 includes the instruction-processing portion of processor 102 . Specifically, core power area 126 includes arithmetic-logic unit 104 , register files 106 , pipelines 108 , and possibly level one (L1) caches 110 . Note that L1 caches 110 can alternatively be located in non-core power area 124 .
Arithmetic-logic unit 104 provides computational and logical operations for processor 102 . Register files 106 provide source operands, intermediate storage, and destination locations for instructions being executed by arithmetic-logic unit 104 . Pipelines 108 provides a steady stream of instructions to arithmetic-logic unit 104 . Instructions in pipelines 108 are decoded in transit. Therefore, pipelines 108 may contain instructions in various stages of decoding and execution. L1 caches 110 include data caches and instruction caches for arithmetic-logic unit 104 . L1 caches 10 are comprised of very high-speed memory to provide fast access for instructions and data. In one embodiment of the present invention, L1 caches 110 includes a write-through data cache.
Non-core power area 124 comprises the remaining portion of processor 102 and includes interrupt processor 112 , real-time clock 114 , clock distribution circuitry 116 , level two (L2) caches 118 , cache tags 120 , and cache snoop circuitry 122 . In general, non-core power area 124 includes portions of processor 102 that are not directly involved in processing instructions, and that need to operate while instruction processing is halted.
Interrupt processor 112 monitors interrupts 128 and periodically interrupts the execution of applications to provide services to external devices requiring immediate attention. Interrupt processor 112 can also provide a wake-up signal to core power area 126 as described below. Real-time clock 114 provides time-of-day services to processor 102 . Typically, real-time clock 114 is set upon startup from a battery operated real-time clock in the computer and thereafter provides time to the system. Clock distribution circuitry 116 provides clock signals for processor 102 . Distribution of these clock signals can be switched off or reduced for various parts of processor 102 . For example, clock distribution to core power area 126 can be stopped while the clock signals to non-core power area 124 continue. The acts of starting and stopping of these clock signals are known in the art and will not be described further. Real-time clock 114 and clock distribution circuitry 116 receive clock signal 130 from the computer system. Clock signal 130 is the master clock signal for the system.
L2 cache 118 provides a second level cache for processor 102 . Typically, an L2 cache is larger and slower that an L1 cache, but still provides faster access to instructions and data than can be provided by main memory. Cache tags 120 provide an index into data stored in L2 cache 118 . Cache snoop circuitry 122 invalidates cache lines base primarily on other processors accessing their own cache lines, or I/O devices doing memory transfers, even when instruction processing has been halted. L2 cache 118 , cache tags 120 , and cache snoop circuitry 122 communicate with the computer system through memory signals 132 .
Non-core power area 124 receives non-core power 136 and core power area 126 receives core power 134 . The voltage applied for non-core power 136 remains at a voltage that allows circuitry within non-core power area 124 to remain fully active at all times. In contrast, non-core power 136 may provide different voltages to non-core power area 124 based upon the operating mode of processor 102 . For example, if processor 102 is a laptop attached to external electrical power, the voltage provided to non-core power 136 (and to core power 134 during instruction processing) may be higher than the minimum voltage, thus providing faster execution of programs.
The voltage applied to core power 134 remains sufficiently high during instruction processing so that core power area 126 remains fully active. However, when processor 102 receives a signal that processing can be suspended, the voltage supplied by core power 134 can be reduced.
In one embodiment of the present invention, the voltage in core power 134 is reduced to the minimum value that will maintain state information within core power area 126 , but this voltage is not sufficient to allow processing to continue. In another embodiment of the present invention, the voltage at core power 134 is reduced to zero. In this embodiment, the state of core power area 126 is first saved before the voltage is reduced to zero. This state can be saved in a dedicated portion of L2 cache 118 , in main memory, or in another dedicated storage area. Upon receiving an interrupt or other signal indicating that processing is to resume, the voltage in core power 134 is restored to a normal level, saved state is restored, and processing is restarted.
FIG. 1B illustrates an alternative partitioning of power areas within processor 102 in accordance with an embodiment of the present invention. As shown in FIG. 1B , L2 cache 118 , cache tags 120 , and cache snoop circuitry 122 are included in core power area 126 rather than in non-core power area 124 . In this embodiment, the voltage supplied as core power 134 is reduced or set to zero as described above, however, the cache circuitry within processor 102 is also put into the reduced power mode. Prior to reducing the voltage supplied to core power area 126 , data stored in L2 cache 118 is flushed to main memory. Additionally, if the voltage at core power 134 is reduced to zero, the state of processor 102 is first saved in main memory.
Monitoring and Switching
FIG. 2 is a flowchart illustrating the process of monitoring processor load and switching to power saving modes in accordance with an embodiment of the present invention. The system starts by monitoring the processor load (step 202 ). Next, the system determines if the processor will be needed soon (step 204 ). This determination is made based on the current execution pattern and the cost of entering and recovering from nap mode. This cost, calculated in power usage, must be less than the power wasted by not going into nap mode. If the processor will be needed soon at step 204 , the process returns to step 202 to continue monitoring the processor load.
If the processor will not be needed soon at step 204 , the system determines if the processor has been taking long naps recently (step 206 ). If not, the system enters a normal nap mode, which involves halting the processor without reducing any voltages (step 208 ). Typically, halting the processor involves removing the clock signals to the core power area of the processor. After halting the processor, the system waits for an interrupt (step 210 ). Upon receiving an interrupt or other signal requiring a restart, the system restarts instruction processing (step 212 ). After restarting instruction processing, the process returns to step 202 to continue monitoring the processor load.
If the processor has recently been taking long naps at step 206 , the system enters a deep nap mode, which involves saving the state information from the core power area (step 214 ), halting the processor (step 216 ), and then reducing the voltage supplied to the core power area (step 218 ). After reducing the voltage, the system waits for an interrupt (step 220 ).
Upon receiving the interrupt or other signal requiring a restart, the system restores the voltage to the core power area (step 222 ). Next, the modules within the core power area are restarted (step 224 ). The system then restores the state information that was saved at step 214 (step 226 ). After the processor has been restarted, the process returns to step 202 to continue monitoring the processor load. Note that the above description applies when the processor is used to save and restore the state information. In cases where dedicated hardware saves and restores the state information, steps 214 and 216 , and steps 224 and 226 can be reversed. Note also that if the voltage supplied to the core power area 126 is reduced but maintained at a level where modules in the core power do not lose state information, steps 216 and 224 are not required.
The foregoing descriptions of embodiments of the present invention 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. | One embodiment of the present invention provides a system that facilitates reducing static power consumption of a processor. During operation, the system receives a signal indicating that instruction execution within the processor is to be temporarily halted. In response to this signal, the system halts an instruction-processing portion of the processor, and reduces the voltage supplied to the instruction-processing portion of the processor. Full voltage is maintained to a remaining portion of the processor, so that the remaining portion of the processor can continue to operate while the instruction-processing portion of the processor is in reduced power mode. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing hybrid integrated circuits (ICS) and, more particularly, to a method for mounting parts on hybrid integrated circuit boards.
2. Description of the Related Art
After a plurality of circuits such as ICs have been formed on a surface of a silicon wafer by a semiconductor manufacturing process which includes a sequence of process steps such as patterning, ion implantation diffusion, and testing, it has been customary to separate the silicon wafer into individual IC chips in the following manner. As shown in FIG. 1, an adhesive sheet 106 is first applied to the reverse surface 104b of a silicon wafer 104 on which no circuit is formed. The adhesive sheet 106, which is a thin film made of a plastic and coated with an adhesive material, easily undergoes plastic deformation from the application of tensile force. Then, as shown in FIG. 2, grooves 105 for wafer separation are formed along the boundaries between adjacent ICs on the silicon wafer 104 by means of a dicing saw (not shown), the grooves 105 extending from an obverse surface 104a, on which circuits are formed, toward the reverse surface 104b. Each of the grooves 105 is formed to a depth which reaches approximately the mid position of the silicon wafer 104 as viewed in the direction of the thickness thereof.
In addition, as shown in FIG. 1, an elastic sheet 102 having elasticity is carried on a fixed stage 101 made of metal such as stainless steel, and a filter paper 103 is carried on the sheet 102 to protect the obverse surface 104a of the silicon wafer 104. Then, the silicon wafer 104 is carried on the filter paper 103 with the adhesive sheet 106 applied thereto with the surface 104a in contact with the filter paper 103. An aluminum foil 107 having a thickness of some tens of microns is carried on the adhesive sheet 106. In this state, a roller 108 made of stainless steel is rolled over the aluminum foil 107 to apply a downward pressure to the silicon wafer 104. As the roller 108 travels, deformation occurs in the corresponding portion of the sheet 102, and thus the corresponding portion of the silicon wafer 104 is deformed. As a result of the deformation, stresses are concentrated upon the bottom portion of the corresponding groove 105 formed in the silicon wafer 104. Thus, cleavage occurs in the portion of the silicon wafer 104 which extends from the bottom of the groove 105 in the direction of the thickness of the silicon wafer 104, and the adjacent ICs are separated along the cleaved surfaces. In this fashion, as the roller 108 rolls, the silicon wafer is sequentially separated into individual ICs.
Subsequently, the spaces between the adjacent ICs are expanded by applying a tensile force to the adhesive sheet 106, stretching it, and causing plastic deformation of it. Furthermore, the individual ICs are removed from the adhesive sheet 106 and mounted on a circuit board, a lead frame or the like.
However, if the above-described conventional method for separating a silicon wafer is applied to hybrid integrated circuits, the following problems will occur since it is necessary to mount component parts on such a hybrid integrated circuit board. More specifically, if a component part is to be mounted on each separated portion of the circuit board, it is necessary to mount or position each circuit board in place and, hence, the step of mounting parts becomes complicated, thus resulting in an increase in cost. Furthermore, since each separated portion is too small to be easily handled, it is difficult to automate the process for manufacturing hybrid integrated circuits. In contrast, if component parts are mounted prior to wafer separation and the wafer is then separated into individual chips, the following problems occur. When pressure is applied to the board, stresses are applied to the connections of the component parts or the component parts themselves and the reliability of the obtained hybrid integrated circuits may thereby deteriorate. In addition, since various parts are carried on the boards, it is still difficult to automate the process for manufacturing hybrid integrated circuits.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method for manufacturing hybrid integrated circuits which enables the step of mounting component parts to be simplified and automated and which is capable of manufacturing highly reliable hybrid integrated circuits.
According to one aspect of the present invention, a method for manufacturing hybrid integrated circuits comprises the steps of forming a plurality of circuit patterns on a first surface of a board having a first surface and a second surface which are parallel to each other, applying a connecting film to the second surface of the board, separating the board into portions having the respective circuit patterns without cutting the connecting film, mounting component parts on the first surface of the board which correspond to the portions having the respective circuit patterns, and separating the board into the portions having the respective circuit patterns by cutting the connecting film.
According to another aspect of the present invention, a method for manufacturing hybrid integrated circuits comprises the steps of forming, on a surface of a board, a plurality of circuit patterns, together with a connecting film which covers the circuit patterns to connect each of the circuit patterns to an adjacent one, separating the board into portions having the respective circuit patterns without cutting the connecting film, mounting component parts on the surfaces of the board which correspond to the portions having the respective circuit patterns, and separating the board into the portions having the respective circuit patterns by cutting the connecting film.
DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are diagrammatic cross-sectional views illustrating a conventional separation method for effecting separation of a silicon wafer;
FIGS. 3A to 3E are diagrammatic cross-sectional views illustrating the process steps of a manufacturing method according to a first embodiment of the present invention; and
FIGS. 4A to 4C are diagrammatic cross-sectional views illustrating the process steps of a manufacturing method according to a second embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
A first embodiment is shown in FIGS. 3A to 3E. First, after a plurality of hybrid integrated circuit patterns have been formed on a 96% alumina ceramic board 1 of 0.8 mm thickness, the boundaries between adjacent circuit patterns are irradiated with a CO 2 laser beam from the obverse surface 1a and thus grooves 2 such as those shown in FIG. 3A are formed for the purpose of board separation. The irradiating conditions for the CO 2 laser beam in this case are selected so that the grooves 2 may reach approximately the mid portion of the board 1 in the direction of the thickness thereof but may not penetrate through the board 1 to the reverse surface 1b. A polyimide precursor varnish 4 is disposed on a 50 μm thick polyimide film 3 which serves as a heat resistant connecting film.
Second, as shown in FIG. 3B, the board 1 is applied to the polyimide precursor varnish 4 coating on the polyimide film 3 with the reverse surface 1b thereof in contact with the polyimide precursor varnish 4. The polyimide precursor varnish 4 is heated to a temperature of 350° C. in a nitrogen atmosphere and thereby hardened to form a polyimide resin 10. Thus, the board 1 and the polyimide film 3 are bonded to each other.
Then, for example, the roller 108 shown in FIG. 1 is used to apply a pressure to the board 1 via the polyimide film 3. Stresses are concentrated at the bottom portion of the corresponding groove 2, stretching the groove 2 under pressure, thereby forming a fissure 5 which, as shown in FIG. 3C, extends from the bottom of the groove 2 to the reverse surface 1b of the board 1. The magnitude of the pressure applied to the board 1 is selected so that the polyimide film 3 remains intact. In this fashion, the board 1 alone is separated into portions, each having a circuit pattern.
Subsequently, as shown in FIG. 3D, a component part 6 is applied via a solder bead 7 on the obverse surface 1a of each separated portion of the board 1. The solder beads 7 are melted by heating all the separated portions of the board 1, thereby securing the component parts 6 to the respective separated portions. After cooling, a CO 2 laser beam is irradiated onto each of the boundaries between the adjacent circuit patterns, as indicated by arrows in FIG. 3D, from the same side as the back of the polyimide film 3, thereby cutting the polyimide film 3 and the polyimide resin 10. Thus, the board 1 is separated into IC chips each having a predetermined circuit pattern together with the polyimide film 3, whereby a hybrid integrated circuit 11 such as that shown in FIG. 3E is obtained.
FIGS. 4A to 4C show a method for manufacturing hybrid integrated circuits according to a second embodiment of the present invention. A thick film of silver palladium paste is affixed, by screen process printing, onto the 96% alumina ceramic board 1 having a thickness of 0.8 mm to form a predetermined pattern thereon. Thereafter, as shown in FIG. 4A, a silver palladium conductor 12 is formed by baking it at a temperature of 850° C. in air. Second, a polyimide precursor varnish of fixed thickness is applied the obverse surface 1a of the board 1 and the silver palladium conductor 12. After drying, patterning is effected onto the polyimide precursor varnish by a photolithographic process to expose the portions of the silver palladium conductor 12 which are to be connected to an upper conductor layer (not shown).
Subsequently, a reaction to convert the polyimide precursor varnish into an imide compound is accelerated by heating at a temperature of 350° C. for one hour in a nitrogen atmosphere, thereby forming a polyimide film 13. After a copper film has been formed over the polyimide film 13 by vacuum deposition, a predetermined pattern is formed in the copper film by a photolithographic process to provide a copper layer 14.
In this fashion, a plurality of hybrid integrated circuit patterns are formed on the board 1 at the same time, but the polyimide film 13 is also formed over the obverse surface 1a of the board 1 to cover all the hybrid integrated circuit patterns.
Then, a CO 2 laser beam is irradiated onto each of the portions of the reverse surface 1b which correspond to the boundaries between the adjacent hybrid integrated circuit patterns, and thus grooves 15 (one of them is shown in FIG. 4B) are formed. The irradiating conditions for the CO 2 laser beam in this case are selected so that the grooves 15 reach approximately the mid portion of the board 1 in the direction of the thickness thereof but do not penetrate through the board 1 to the obverse surface 1a.
Then, for example, the roller 108 shown in FIG. 1 is used to apply a pressure to the board 1 via the polyimide film 13 to concentrate stresses upon the bottom portion of the corresponding groove 15 to stretch the groove 15 under pressure, thereby forming a fissure 16 which, as shown in FIG. 4C, extends from the bottom of the groove 15 to the obverse surface 1a of the board 1. The magnitude of the pressure applied to the board 1 is determined so that the polyimide film 13 remains intact. In this fashion, the board 1 alone is separated into portions each having a circuit pattern.
Subsequently, a component part (not shown) is mounted via a solder bead (not shown) on the obverse surface 1a of each separated portion of the board 1, and the solder beads are melted by heating all the separated portions of the board 1, thereby securing the component parts to the respective separated portions. Then, a CO 2 laser beam is irradiated onto each of the boundaries between the adjacent circuit patterns from the same side as the polyimide film 13, thereby cutting the polyimide film 13. Thus, the board 1 is separated into IC chips each having a predetermined circuit pattern together with the polyimide film 13, whereby separate hybrid integrated circuits are obtained.
It will be appreciated from the foregoing that each of the first and second embodiments has the following advantages. Since the separation of the board 1 is carried out before the component parts are placed on the board 1, the component parts or the connections thereof are not adversely affected during separation. Since the separated portions of the board 1 are connected by the polyimide film 3 or 13 and, in this state, the component parts are mounted on the respective separated portions, the process for mounting the component parts is simplified. In consequence, it is possible to easily automate the process for manufacturing hybrid integrated circuits.
In addition, the second embodiment provides the following advantage. Since the polyimide film 13 which is one constituent element of each of the hybrid integrated circuit patterns, connects the separated portions of the board 1, it is not necessary to stick an exclusive connecting film to the board 1. Accordingly, the total number of process steps decreases and, therefore, the manufacturing cost is reduced.
Although each of the first and second embodiments is described with illustrative reference to the alumina ceramic board, similar effects and advantages can also be achieved by using materials of any kind that can be separated by forming separating grooves and causing stress concentration therealong. For example, it is possible to use an aluminum nitride board. In addition, although such separating grooves are formed for the convenience of board separation, the board may be separated without forming any separating grooves.
In each of the first and second embodiments, the heat resistant polyimide film is used as a connecting film for the purpose of illustration, but the connecting film is not limited to polyimide. For example, it is possible to use a metal foil or a heat resistant polymer film of any type that can withstand heat generated during a soldering process. It is preferable to use a flexible material. In place of the polyimide precursor varnish, a heat resistant epoxy resin, a triazinebismaleide-type resin or the like may be employed.
Furthermore, the connecting film may be cut by the method other than a CO 2 laser, for example, mechanical cutting using a cutter. | In a method for manufacturing hybrid integrated circuits, a plurality of circuit patterns are formed on one surface of a board, and a connecting film is stuck onto the other surface of the board. Then, the board is divided into portions having the respective circuit patterns while leaving the connecting film intact and component parts are mounted on the portions. Finally, the individual portions are separated by cutting the connecting film. The circuit patterns may be formed over one surface of the board and covered with a connecting film. The connecting film may be a constituent element of each circuit pattern, such as an insulating layer disposed between conducting layers. |
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 09/972,521, field Oct. 5, 2001, of the same title, which is a continuation-in-part of U.S. patent application Ser. No. 09/530,628 filed May 2, 2000, entitled “High Pressure Fuel Supply System for Natural Gas Vehicles”, now abandoned. The '628 application related to and claimed priority benefits from U.S. patent application Ser. No. 08/965,969 of the same title, now U.S. Pat. No. 5,884,488. The '521 and '628 applications and the '969 patent are hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
[0002] This invention relates to medium and high pressure pump systems for supplying a cryogenic fluid from a storage tank. A particularly advantageous application for the system and methods is for supplying a cryogenically stored fuel to an internal combustion engine.
BACKGROUND OF THE INVENTION
[0003] Natural gas has been used as a fuel for piston engine driven vehicles for over fifty years but the drive to improve efficiency and reduce pollution is causing continual change and improvements in the available technology. In the past, natural gas driven vehicles (NGV) were naturally fumigated, that is, natural gas was introduced into the cylinders through the intake manifold, mixed with the intake air and fed into the cylinders at relatively low pressure. The fuel supply system for such an NGV is relatively simple. Fuel is held in and supplied from a liquefied natural gas (LNG) vehicle tank with working pressure just above the engine inlet pressure, or from compressed natural gas cylinders (CNG) through regulators that reduce the pressure to the engine inlet pressure.
[0004] Compressed natural gas (CNG) is commonly stored at ambient temperatures at pressures up to 3600 pounds per square inch (24,925 kPa), and is unsuitable for trucks and buses due to the limited operating range and heavy weight of the CNG storage tanks.
[0005] On the other hand, liquefied natural gas (LNG) is normally stored at temperatures of between about −240° F. and −175° F. (about −150° C. and −115° C.) and at pressures of between about 15 and 200 psig (204 and 1477 kPa) in a cryogenic tank, providing an energy density of about four times that of CNG.
[0006] However, better efficiency and emissions can be achieved if the natural gas is injected directly into the cylinders under high pressure at the end of the compression stroke of the piston. This requires a fuel supply system that can deliver the natural gas at a pressure of 3000 pounds per square inch gauge (psig) and above. This makes it impossible to deliver the fuel directly from a conventional LNG vehicle tank and it is impractical and uneconomical to build an LNG tank with such a high operating pressure. Equally, it is impossible to deliver the natural gas fuel directly from a conventional CNG tank as the pressure in such a tank is lower than the injection pressure as soon as a small amount of fuel has been withdrawn from the CNG tank. In both cases, a booster pump is required to boost the pressure from storage pressure to injection pressure.
[0007] Liquid Natural Gas (LNG) Pump
[0008] High pressure cryogenic pumps have been on the market for many years, but it has proven difficult to adapt these pumps to the size and demand of a vehicle pump. In general, cryogenic pumps should have a positive suction pressure. It has therefore been common practice to place the pump directly in the liquid so that the head of the liquid will supply the desired pressure. The problem with this approach is that it introduces a large heat leak into the LNG storage tank and consequently reduces the holding time of the tank. The holding time is the time it takes for the pressure to reach relief valve set pressure.
[0009] Some manufacturers have placed the pump outside the storage tank and have reduced the required suction pressure by using a large first stage suction chamber. The excess LNG which is drawn into such a chamber, over that which can fill a second chamber, is returned to the LNG tank and again, additional heat is introduced into the LNG, which is undesirable.
[0010] Another problem with a pumped LNG supply is that it is difficult to remove vapor from the LNG storage tank. With low pressure gas supply systems, this is easily done. If the pressure in the LNG tank is high, fuel is supplied from the vapor phase thereby reducing the pressure. If pressure is low, fuel is supplied from the liquid phase. This characteristic of a low pressure system substantially lengthens the holding time, which is very desirable as mentioned above. Extending the holding time cannot be done with conventional LNG pump systems that draw from the liquid phase only and cannot remove vapor.
[0011] Gram U.S. Pat. No. 5,411,374, issued May 2, 1995, and its two divisional patents, U.S. Pat. No. 5,477,690, issued Dec. 26, 1995, and U.S. Pat. No. 5,551,488, issued Sep. 3, 1996, disclose embodiments of a cryogenic fluid pump system and method of pumping cryogenic fluid. The cryogenic fluid piston pump functions as a stationary dispensing pump, mobile vehicle fuel pump, and the like, and can pump vapor and liquid efficiently even at negative feed pressures, thus permitting pump location outside a liquid container. The piston inducts fluid by removing vapor from liquid in an inlet conduit faster than the liquid therein can vaporize by absorbing heat and causing pressure in the inlet conduit to be lowered. The differential pressure between the vapor pressure in the conduit and the vapor pressure within the tank pushes the liquid into the pump. The piston moves at essentially constant velocity throughout an induction stroke to generate an essentially steady state induction flow with negligible restriction of flow through an inlet port. The stroke displacement volume is at least two orders of magnitude greater than residual or dead volume remaining in cylinder during stroke changeover, and is greater than the volume of inlet conduit. As a fuel pump, the pump selectively receives cryogenic liquid and vapor from respective conduits communicating with the tank, and pumps cryogenic liquid to satisfy relatively heavy fuel demand of the engine, which, when satisfied, also pumps vapor to reduce vapor pressure in the tank while sometimes satisfying relatively lighter fuel demand.
[0012] Conventional, prior art cryogenic pumps are typically centrifugal pumps, which are placed either in the liquid inside the storage tank, or below the storage tank in a separate chamber with a large suction line leading from the tank, with both the pump and suction line being well insulated. Because a cryogenic liquid is at its boiling temperature when stored, heat leaked into the suction line and reduction in pressure will cause vapor to be formed. Thus, if the centrifugal pump is placed outside the tank, vapor is formed and the vapor will cause the pump to cavitate and the flow to stop. Consequently, prior art cryogenic pumps require a positive feed pressure to prevent or reduce the tendency to cavitation of the pump. In a stationary system, the positive feed pressure is typically attained by locating the pump several feet, for example, 5-10 feet (about 2-3 meters) below the lowest level of the liquid within the tank, and such installations are usually very costly. On board fuel storage systems for vehicles use other ways to provide positive feed pressure. Also, centrifugal pumps cannot easily generate high discharge pressures to properly inject fuel directly into the cylinder of an internal combustion engine and that are also desirable to reduce fuelling time for fuelling station applications.
[0013] Reciprocating piston pumps have been used for pumping LNG when high discharge pressures are required or desired, but such pumps also require a positive feed pressure to reduce efficiency losses that can arise with a relatively high speed piston pump. Prior art LNG piston pumps are crankshaft driven at between 200 and 500 RPM with relatively small displacements of approximately 10 cubic inches (164 cubic centimeters). Such pumps are commonly used for developing high pressures required for filling CNG cylinders and usually have a relatively low delivery capacity of up to about 5 gallons per minute (20 liters per minute). Such pumps are single acting, that is, they have a single chamber in which an induction stroke is followed by a discharge stroke, and thus the inlet flow will be stopped half of the time while the piston executes the discharge stroke. Furthermore, as the piston is driven by a crank shaft which produces quasi-simple harmonic motion, the piston has a velocity which changes constantly throughout its stroke, with 70% of the displacement of the piston taking place during the time of one-half of the cycle, that is, one-half of the stroke, and 30% of the piston displacement occurring in the remaining half cycle time. The variations in speed of the piston are repeated 200-500 times per minute, and generate corresponding pressure pulses in the inlet conduit, which cause the liquid to vaporize and condense rapidly. This results in zero inlet flow unless gravity or an inlet pressure above boiling pressure of the liquid forces the liquid into the pump. In addition, the relatively small displacement of these pumps results in relatively small inlet valves which, when opened, tend to unduly restrict flow through the valves. Thus, such pumps require a positive inlet or feed pressure of about 5 to 10 psig (135 to 170 kPa) at the feed or inlet of the reciprocating pump unless the inlet valve is submerged in the cryogenic liquid in which case the feed pressure can be reduced. Large cryogenic piston pumps, with a capacity of about 40 gallons per minute (150 liters per minute) have been built, but such pumps are designed for very high pressure delivery, require a positive feed pressure and are extremely costly.
BRIEF SUMMARY OF THE INVENTION
[0014] A medium or high pressure pump system supplies a cryogenic fluid from a storage tank and a method of operating such a system. The system comprises a pump that is operable to pump cryogenic liquid or a mixture of cryogenic liquid and vapor, and the method comprises controlling mass flow rate by supplying to the pump from the storage tank, cryogenic liquid or a mixture of cryogenic vapor and liquid. More particularly, the method comprises:
[0015] (a) selecting a first operating mode in which cryogenic liquid from the storage tank is supplied to the pump to substantially fill a compression chamber with liquid to achieve a high mass flow rate; and
[0016] (b) selecting a second operating mode to achieve a mass flow rate lower than the first operating mode by selectively supplying cryogenic liquid and vapor simultaneously to the pump from the storage tank wherein the vapor fraction is higher for the second operating mode compared to the vapor fraction for the first operating mode.
[0017] The pump system may comprise an inducer disposed between the storage tank and the pump compression chamber. The inducer precompresses the cryogenic fluid prior to introducing the fluid to the pump compression chamber(s). When the pump system is operating at maximum capacity by selecting the first operating mode, the inducer stages are defined as the stages in which substantially all of the cryogenic vapor is condensed, such that only cryogenic liquid is supplied to the pump compression chamber(s). Accordingly, when the pump system comprises an inducer, some vapor may be supplied to the system even when the first operating mode is selected. When the second operating mode is selected, some vapor is supplied to the compression chamber(s) where such vapor is condensed during the compression cycle, but with a consequent reduction in the flow rate through the pump system.
[0018] When the pump system does not comprise an inducer, and the first operating mode is selected, then only liquid is supplied from the storage tank so that the pump compression chamber is substantially filled with liquid to achieve a high mass flow rate. When the second operating mode is selected, cryogenic vapor and liquid are simultaneously supplied to the pump compression chamber with the vapor being condensed within the pump compression chamber during the compression cycle, but with the flow capacity through the pump being lower than the flow capacity through the pump when the first operating mode is selected.
[0019] Because it is advantageous to store some gaseous fuels under cryogenic conditions, the method may be employed to pump a cryogenically stored fuel to an internal combustion engine. To provide a steady supply of high pressure fuel to an engine the method may comprise delivering fuel from the pump to an accumulator vessel and selecting an operating mode to control mass flow rate to maintain pressure within a predetermined range within the accumulator vessel. The volume of the fuel conduits and manifolds between the pump and engine may be sized to have a volume such that these conduits and manifolds themselves act as the accumulator, obviating the need for an actual “vessel”. The pressure may be monitored within the fuel conduit or manifold downstream from the pump, or within an accumulator vessel, if employed. The mass flow rate supplied by the pump system is controllable to maintain the monitored pressure within a predetermined range to ensure sufficient pressure for supplying the fuel to the desired application, such as an internal combustion engine. The method may further comprise increasing the vapor fraction supplied to the pump when vapor pressure within the storage tank is higher than a predetermined value or when the monitored pressure downstream from the pump is above a predetermined set point. That is, the vapor fraction can be increased to reduce vapor pressure in the storage tank to reduce or prevent the need for venting, or to continue operation of the pump system at a lower mass flow rate when pressure downstream of the pump is above a predetermined set point.
[0020] In a preferred arrangement for the pump, the inlet is associated with a first end of the pump and the outlet is associated with a second end, which is opposite to the first end. The heat of compression transferred to the cryogenic fluid during the compression process dissipates from the pump with the discharged fluid. With this preferred pump arrangement, the fluid passages within the pump are preferably arranged so that the cryogenic fluid flows through the pump progressively from the first end to the second end. In this arrangement, heat from the compression process is not transferred from the discharge fluid to the fluid being induced into the pump, as is the case with prior art pumps that have inlets proximate to outlets or discharge conduits proximate to induction conduits or chambers.
[0021] When the second operating mode is selected, the vapor fraction that is supplied to the pump is preferably maintained below a predetermined maximum vapor fraction by restricting the flow of vapor through a conduit between the tank and the pump. When the vapor fraction is too high, a reciprocating pump is unable to condense substantially all of the cryogenic vapor, and the pump will not operate efficiently. For specific operating conditions, maximum vapor fraction may be empirically determined or calculated to designate as the “maximum” vapor fraction, a vapor fraction that maximizes the amount of vapor that may be supplied to the pump while ensuring that substantially all of the vapor supplied to the pump during normal operation is condensable within the pump.
[0022] For example, in some systems an orifice may be employed for restricting the flow rate of vapor through the conduit between the tank and the pump. In other embodiments, the system may comprise a metering valve for controlling the flow rate through the vapor conduit between the tank and the pump. In such systems an electronic controller may be programmed to change the setting of the metering valve to control the amount of vapor that flows through the conduit in response to measured operating conditions, such as pressure measured downstream from the pump or vapor pressure measured in the storage tank.
[0023] When the first operating mode is selected, the method may further comprise closing a valve to prevent vapor from being supplied from an ullage space of the storage tank to the pump. “Ullage space” is defined herein as the vapor space within the storage tank. The valve is preferably an electronically controlled valve with an actuator, such as a solenoid, mechanical, pneumatic, or hydraulic actuation mechanism.
[0024] In a preferred method of operating the pump, it is driven at substantially a constant speed by employing a linear hydraulic motor. For example, the pump may be set to operable at a constant speed between 5 and 30 cycles per minute.
[0025] When the pump has been shut down for a period of time, it may be desirable to cool down the pump before it can begin to function properly. That is, if the temperature of the pump is too warm, cryogenic fluid introduced into the pump will immediately boil or vaporize, preventing the pump from being able to pump cryogenic fluid to higher pressures. A preferred cooling procedure for preparing the pump for operation comprises the following steps:
[0026] (a) introducing cryogenic liquid from the tank into the pump;
[0027] (b) returning vapor created within the pump to the tank, thereby increasing pressure within the tank; and
[0028] (c) using the increased pressure within the tank to force more cryogenic liquid from the tank into the pump.
[0029] Once the pump has been cooled to the normal operating temperature, a valve controlling the flow of cryogenic fluid back from the pump to the storage tank is closed. That is, once the pump is cooled to predetermined temperature at which the pump is operable to pump the cryogenic liquid and vapor in one of the first or second operating modes, vapor is prevented from returning to the tank.
[0030] In a second preferred embodiment, the system comprises a multi-stage pump that has at least three chambers for compressing cryogenic fluid. A first chamber and a second chamber each have a volume that is larger than a third chamber. In this second embodiment, the first and second chambers act as an inducer stage with the third chamber acting as a compression chamber. For this second embodiment, the method comprises:
[0031] selectively supplying a cryogenic liquid or a mixture of cryogenic liquid and vapor to the pump such that cryogenic fluid flows through an inlet into the first chamber;
[0032] compressing and condensing cryogenic vapor and compressing cryogenic liquid within the first chamber and transferring cryogenic fluid from the first chamber to the second chamber;
[0033] compressing cryogenic fluid within the second chamber and transferring the cryogenic fluid from the second chamber to the third chamber until the third chamber is filled, and then transferring cryogenic fluid remaining within the second chamber to the first chamber; and
[0034] compressing cryogenic fluid within the third chamber and discharging compressed cryogenic fluid from the third chamber through an outlet port.
[0035] In this second embodiment of the method, when a first operating mode is selected and the flow rate through the pump is maximized, the cryogenic fluid is being compressed within the second chamber and by the end of the compression stroke, substantially all of the gas or vapor that was within the second chamber at the beginning of the compression stroke has been condensed, such that substantially all of the fluid that is transferred to the third chamber is cryogenic liquid. When a second operating mode is selected and the pump operates at a lower flow rate some vapor may be transferred from the second chamber to the third chamber with the pump then operating with a reduced flow capacity.
[0036] In this second embodiment, excess cryogenic fluid induced into the pump is advantageously recycled from the second chamber to the first chamber, so that no vapor is returned from the pump to the storage tank during normal operation. This is an advantage over known systems that return excess cryogenic fluid to the storage tank since such systems introduce heat into the storage tank with the return of the excess fluid.
[0037] The method may further comprise employing a pressure actuated relief valve for controlling the return of cryogenic fluid from the second chamber to the first chamber.
[0038] The method may further comprise supplying the fluid from the pump to an accumulator and selectively introducing only cryogenic liquid to the pump when pressure within the accumulator decreases below a predetermined value. The accumulator may be an actual pressure vessel or the fluid conduits and manifolds themselves, which collectively provide an accumulator volume.
[0039] When the pump comprises at least three chambers for compressing cryogenic fluid and a reciprocating piston assembly divides the three chambers, in a preferred method the pump operates in the following manner:
[0040] (a) during a retraction stroke, retracting a piston, and thereby,
[0041] increasing the volume of a first chamber of the pump and selectively introducing into the first chamber, a cryogenic liquid or a mixture of cryogenic vapor and liquid supplied from the storage tank;
[0042] decreasing the volume of a second chamber of the pump, compressing cryogenic fluid within the second chamber, transferring cryogenic fluid from the second chamber into a third chamber until the third chamber is filled, and then returning cryogenic fluid from the second chamber to the first chamber until the retraction stroke is completed;
[0043] increasing the volume of a third chamber of the pump and receiving cryogenic fluid from the second chamber into the third chamber until the third chamber is full; and
[0044] (b) during an extension stroke, extending the piston, and thereby,
[0045] decreasing the volume of the first chamber, compressing cryogenic fluid within the first chamber, and transferring cryogenic fluid within the first chamber to the second chamber;
[0046] increasing the volume of the second chamber and drawing fluid into the second chamber from the first chamber;
[0047] decreasing the volume of the third chamber, compressing fluid within the third chamber, and ejecting cryogenic fluid through an outlet from the third chamber.
[0048] At the end of the extension stroke, the volume of the second chamber is preferably between about four and ten times larger than the volume of the third chamber when the piston is at the end of the retraction stroke. Further, the volume of the first chamber at the end of the retraction stroke is preferably larger or substantially equal to the volume of the second chamber at the end of the extension stroke. With this arrangement, the first chamber has sufficient volume to accept substantially all of the excess cryogenic fluid that may be recycled from the second chamber to the first chamber. In a preferred configuration of the pump, at the end of the extension stroke, the volume of the third chamber is substantially zero.
[0049] In a third preferred method of operating a reciprocating pump for pumping a cryogenic fluid from a sump of a cryogenic storage tank, the pump comprises at least two chambers divided by a reciprocating piston assembly. This method comprises the following steps:
[0050] (a) during a retraction stroke,
[0051] increasing the volume of a first compression chamber of the pump and introducing into the first compression chamber a cryogenic fluid supplied from the storage tank;
[0052] decreasing the volume of a second compression chamber of the pump and thereby compressing fluid within the second compression chamber and ejecting compressed fluid from the second compression chamber and out of the pump; and
[0053] (b) during an extension stroke,
[0054] decreasing the volume of the first compression chamber and transferring fluid within the first compression chamber to the second compression chamber;
[0055] increasing the volume of the second compression chamber and drawing cryogenic fluid into the second compression chamber from the first compression chamber, wherein the volume of the second compression chamber at the end of the extension stroke is less than the volume of the first compression chamber at the end of the retraction stroke so that when the volume of the second compression chamber is filled by fluid flowing into the second compression chamber from the first compression chamber, the remainder fluid is ejected from the second compression chamber and out of the pump.
[0056] In this embodiment, the volume of the second compression chamber at the end of the extension stroke is about half or less than half of the volume of the first compression chamber at the end of the retraction stroke. Preferably, the relative sizes of the first and second compression chambers are such that about an equal amount of fluid is discharged during the retraction and extension strokes.
[0057] The method may further comprise condensing cryogenic vapor in an inducer stage prior to introducing the cryogenic fluid into the first compression chamber.
[0058] The preferred system for pumping a cryogenic fluid from a storage tank comprises:
[0059] (a) a reciprocating pump comprising a suction inlet and a discharge outlet;
[0060] (b) a first pipe fluidly connecting the suction inlet to liquid within the interior of the storage tank;
[0061] (c) a second pipe fluidly connecting the suction inlet to vapor within the storage tank; and
[0062] (d) a restriction in the second pipe for limiting flow through the second pipe so that a mixture of liquid and vapor may be supplied from the storage tank to the suction inlet.
[0063] The restriction may be made, for example, by an orifice, a narrowing of the second pipe, or a metering valve. The restriction is preferably sized to maintain a vapor fraction supplied to the pump that is equal to or less than a predetermined maximum vapor fraction.
[0064] An advantage of one embodiment of the pump is that the pump may comprise a cold end disposed within a sump and a warm end opposite to the cold end, wherein the suction inlet is associated with the cold end and the discharge outlet is associated with the warm end. This arrangement prevents heat generated from the compression process from being transferred from the discharged cryogenic fluid to the cryogenic fluid being induced into the pump from the sump.
[0065] The system preferably further comprises a linear hydraulic drive connected to a piston of the pump. The linear hydraulic drive permits the piston to be drivable at a constant speed, which helps to reduce the creation of pressure pulses in the discharge pipe. In another embodiment, the pump speed may be changed to provide an additional means for influence the mass flow rate through the system to provide a greater range of selectable flow rates. However, this requires additional controls and apparatus for varying the speed of the hydraulic drive and the pump. The pump is preferably operable by the linear hydraulic drive at a fixed speed or at variable speeds, between 5 and 30 cycles per minute.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0066] The drawings illustrate specific embodiments of the invention, but should not be construed as restricting the scope of the invention:
[0067] [0067]FIG. 1 illustrates a sectional view of an LNG pump assembly that is operable according to a preferred embodiment of the present method. The pump assembly comprises three chambers for compressing cryogenic fluid.
[0068] [0068]FIG. 2 illustrates a schematic flow diagram of an LNG supply system for supplying fuel to an engine according a preferred method, where the LNG pump is external to the LNG tank.
[0069] [0069]FIG. 3 illustrates a section view of another preferred embodiment of a system that is operable according to a preferred embodiment of the present method, where the LNG pump is built into a sump in a storage tank for cryogenic fluids.
[0070] [0070]FIG. 4 illustrates a detailed enlarged section view of the embodiment of FIG. 3, with the LNG pump built into the sump of a storage tank for cryogenic fluids. This embodiment of the LNG pump comprises two chambers for compressing cryogenic fluid and an inlet associated with the cold end that is inserted into a sump and an outlet associated with the opposite end of the LNG pump.
[0071] [0071]FIG. 5 illustrates a detailed enlarged section view of a yet another embodiment of a system operable according to a preferred embodiment of the present method; this system includes an LNG pump built into the LNG tank in association with an inducer.
[0072] [0072]FIG. 6 illustrates a section view of a sump when the LNG pump is withdrawn.
DETAILED DESCRIPTION OF THE INVENTION
[0073] Natural gas burning engines can be broadly classified into two classes, namely those having a low pressure fuel system and those having a high pressure fuel system. A low pressure fuel system is defined as a fuel system of an engine that operates on a fuel pressure that is lower than the minimum operating pressure of the tank. In this type of low pressure system, no fuel pump is required and the tank has a vapor conduit that removes vapor from the tank, and a liquid conduit that removes liquid from the tank. Each conduit is controlled by a respective valve, which in turn is controlled by at least one pressure sensor. The engine normally receives fuel through the liquid conduit, except in instances where tank pressure exceeds a specified pressure, for example, about 60 psig (516 kPa), in which case the vapor conduit is opened, so as to release some vapor to the engine, which reduces pressure in the tank, thus enabling longer holding times. This is a simple system that ensures that tank pressure is kept low by taking fuel in the vapor phase from the tank whenever pressure in the tank is over the specified pressure level.
[0074] In contrast, a high pressure fuel system requires a fuel pump that supplies fuel at a pressure of about 3,000 psig (20,771 kPa), depending on fuel system parameters. This is usually accomplished by a small displacement piston pump located inside the vehicle tank with a submerged inlet to ensure a positive feed pressure. Such installation is difficult to install and service, and makes the fuel tank and pump assembly relatively large. Because the pump can only pump liquid, vapor generated by heat leak and working of the pump will decrease the holding time of the tank by a substantial amount, and result in high fuel loss because the vapor should be vented prior to refueling the tank. This venting of vapor reduces effective capacity of the vehicle tanks still further, compounding the difficulty of use of LNG in a vehicle tank. It is believed that no single pump can efficiently pump both liquid and vapor, or a mixture of both, and thus a system that can remove and burn vapor in the engine is not available for high pressure fuel systems. Also, conventional piston pumps require a net positive pressure at the inlet port, which severely limits location of such pumps, and in particular such pumps cannot be used with a vehicle tank having a conventional “over the top” liquid outlet. Many problems would be solved if a vehicle pump could be developed which could operate with a negative suction pressure, which would permit the vehicle pump to be located outside the vehicle tank and placed wherever space is available in the vehicle.
[0075] Referring to FIGS. 1 and 2, which show respectively a section view of an LNG pump assembly according to a preferred embodiment of the present system, and a schematic flow diagram of an LNG supply system to an engine according to a preferred embodiment of the present system, where the LNG pump is external to the LNG tank, FIG. 1 illustrates cylindrically shaped pump 2 which holds inside cylinder 4 reciprocating piston 6 which is driven by cylindrical shaft 8 that is connected to an external driving force. The ends of the cylinder are capped with heads 10 and 11 and bolts 12 . Teflon® or similar thermal insulation 14 such as UHMW (a well-known but less expensive cryogenic insulation compared to Teflon®) encloses shaft 8 and reduces heat loss. The end of piston 6 , opposite shaft 8 , has hollow cylindrical rod 16 , which reciprocates inside sleeve 18 , which is also insulated with thermal insulation 20 such as Teflon or a similar material. This configuration forms chambers 21 , 23 and 25 . Check valves 24 and 27 are located within piston 6 , check valve 26 is located within shaft 16 and check valve 28 is preferably located within head 10 . One-way check valve 7 is also located in association with inlet 5 . While not illustrated in FIG. 1, the exterior of pump 2 is also insulated to prevent heat transfer into the pump. Lines leading to and from the pump are also insulated, as is conventional in the art.
[0076] The first main chamber comprising first and second chambers 21 and 23 separated by piston 6 is between about four and ten times larger than third chamber 25 . In one embodiment, first and second chambers 21 and 23 are preferably about 5 times larger than third chamber 25 . When piston 6 retracts to the left, natural gas liquid and vapor is drawn into first chamber 21 of cylinder 4 through inlet 5 and check valve 7 , which is located outside cylinder 4 . When piston 6 extends to the right, the mixture of liquid and vapor in first chamber 21 is moved into second chamber 23 through check valve 24 . When piston 6 retracts again to the left, the liquid and vapor mixture in second chamber 23 is compressed and forced into third chamber 25 through the passage in hollow piston rod 16 and check valve 26 .
[0077] The mixture of liquid and vapor in first chamber 21 is at a saturation pressure and temperature during the retracting suction stroke as piston 6 moves to the left. When this mixture is compressed in second chamber 23 on the second retraction stroke, the vapor condenses, the total volume is reduced and the liquid is then pushed into third chamber 25 through the passage in hollow rod 16 and check valve 26 . If too much liquid is initially drawn into second chamber 23 , relief valve 27 will open at a given pressure and let the excess fluid move back into first chamber 21 , thereby returning no liquid to LNG storage tank assembly 30 under normal operating conditions.
[0078] [0078]FIG. 2 illustrates a schematic flow diagram of an LNG supply system to an engine according to a preferred embodiment of the present system, in which the LNG pump is external to LNG tank assembly 30 . FIG. 2 illustrates LNG tank assembly 30 , hydraulic pump 32 that drives LNG pump 2 , vaporizer 34 , accumulator 36 and engine 38 . The volume in the fuel conduits between pump 2 and engine 38 may be sized so that the fuel conduits themselves act as accumulator 36 and an actual accumulator vessel is not required. LNG tank assembly 30 has inner tank 42 , and a vacuum between the outer tank and inner tank 42 , for insulation. With reference to pump 2 of FIG. 1, the liquid that enters third chamber 25 through check valve 26 is compressed to the required high pressure when piston 6 extends to the right. It will then be ejected from third chamber 25 through check valve 28 to flow through vaporizer 34 , where the liquid is converted to gas, and into accumulator 36 as compressed natural gas. The compressed natural gas held in accumulator 36 can be maintained at a pressure sufficient for injecting the natural gas through injection valves directly into the combustion chambers of engine 38 .
[0079] In normal operation, pump 2 will draw a mixture of vapor and liquid from LNG tank assembly 30 . Suction line 31 is connected not only to the bottom portion of inner tank 42 , where the end of line 31 opens below the level of the liquid therein, but also to the upper portion of inner tank 42 , for drawing vapor through line 33 that opens above the level of the liquid within inner tank 42 . Flow of vapor through suction line 31 is controlled by solenoid valve 39 and metering valve 40 . During normal operation, solenoid valve 39 will be open and the amount of vapor drawn into line 31 depends on the setting of metering valve 40 .
[0080] The vapor fraction of the mixture of cryogenic liquid and vapor is defined as the volume of vapor that is supplied to the cryogenic pump divided by the total volume of cryogenic fluid supplied to the cryogenic pump. Through experimentation it has been determined that, depending upon the particular operating conditions, a minimum amount of liquid that should be supplied to the pump to ensure that substantially all of the vapor can be condensed. Accordingly, for efficient operation of the pump, the maximum vapor fraction is achievable by supplying the minimum amount of liquid to condense the vapor within the pump. When the vapor fraction is higher than this maximum vapor fraction, the efficiency of the pump is reduced.
[0081] In the arrangement illustrated in FIG. 2, metering valve 40 may be a manual valve that is set to maintain a vapor fraction that is equal to or less than the maximum vapor fraction determined for most operating conditions. Metering valve 40 may also be electronically controlled to allow the vapor fraction to be changed in response to different operating conditions so that the vapor fraction is always equal to or less than the maximum vapor fraction for the current operating conditions.
[0082] The saturated vapor that is removed from LNG tank assembly 30 will be compressed and condensed in second chamber 23 and further compressed in third chamber 25 of LNG pump 2 , as explained above in relation to FIG. 1, to the desired gas pressure in accumulator 36 .
[0083] When solenoid valve 39 is open, the capacity of pump 2 will be reduced. However, should the pressure downstream from pump 2 get too low, that is, too close to the engine injection pressure because engine 38 requires more fuel, programmed computer controls in controller 43 will close solenoid valve 39 and only LNG from the bottom of tank assembly 30 will flow into pump 2 thereby ensuring that the maximum fuel capacity of LNG pump 2 is achieved.
[0084] [0084]FIG. 2 shows pump 2 located outside LNG tank assembly 30 . If pump 2 is located outside tank assembly 30 , the exterior of the pump is well insulated with conventional insulation material and heat leakage back into LNG tank assembly 30 is prevented because no flow of the fuel into LNG tank assembly 30 is possible. Also, the interior of pump 2 is well insulated by insulation 14 and 20 . But even so, if vehicle engine 38 has not been operated for an extended time, such as when the vehicle is parked, pump 2 may have warmed up relative to the temperature of the liquid in LNG tank assembly 30 . This residual heat in pump 2 would cause LNG drawn into pump 2 to boil and thereby greatly reduce the capacity of pump 2 .
[0085] To reduce the cool down time of pump 2 , when it again begins operation, the programmed controls may open second solenoid valve 41 . Opening of valve 41 enables the vapor created by warm pump 2 to be pumped from second chamber 23 through gas line 45 and line 33 into the upper vapor space of inner tank 42 , thereby increasing the pressure in inner tank 42 , and thereby forcing more liquid from the bottom of inner tank 42 into pump 2 , which will then in turn be cooled down faster than would be the case if solenoid 41 is not opened.
[0086] In other embodiments, such as those illustrated in FIGS. 3 through 6, the LNG pump may be located in sump space 44 inside the vacuum space between the outer tank and inner tank 42 of LNG tank assembly 30 . In the embodiment shown in FIG. 3, greater efficiency and reduced heat leak is gained by locating the cold end of pump 48 in the vacuum space of LNG tank assembly 30 . However, to do so, several unique features should be incorporated into a pump designed for this purpose. Also, sump space 44 should be built into the outer tank.
[0087] As explained before, a vacuum between the outer tank and inner tank 42 insulates LNG tank assembly 30 . For maintenance purposes, pump 48 should be removable from sump space 44 without disturbing the high vacuum that thermally insulates tank assembly 30 . This can be done by permanently connecting liquid suction line 31 from inner tank 42 to small sump 46 which is located in sump space 44 in the enlargement in the outer tank of tank assembly 30 , and installing the cold end of pump 48 in sump 46 with pressure seal 47 located so that only the portion of pump 48 within sump 46 is surrounded with LNG. Pump 48 can be removed only when inner tank 42 is empty of LNG. Otherwise, LNG would flow through line 31 . The configuration of a built-in pump has the added advantage that no pump cool down procedure is required during start-up. LNG runs freely through line 31 into sump 46 as soon as pumping is started and when pumping is stopped for an extended time, the LNG in line 31 and sump 46 will be pushed back into inner tank 42 by vapor pressure thereby reducing the heat loss.
[0088] It is usually highly desirable for efficiency to have a double acting pump, because then the pump is working in both directions. But a conventional double acting pump typically has inlet and outlet valves at either end, which makes such a design unsuitable as a built-in pump. It is difficult to remove pump 48 unless sump 46 is very large. The unique features of the pumps illustrated in FIGS. 3 through 5 where the exhaust valve is piped to the exterior end have avoided this difficulty.
[0089] Another advantage of this configuration illustrated in FIGS. 3 and 4 is that it allows check valve 63 to be larger, compared to known reciprocating pumps, which have an inlet and an outlet associated with the same end. With a configuration like the one illustrated in FIGS. 3 and 4, the cold end of pump 48 need not also accommodate space for an outlet. This allows essentially the entire cold end area of pump 48 to be available for accommodating check valve 63 . Employing a larger check valve at the pump inlet reduces entrance losses and enables pump 48 to operate with a lower net positive suction head (NPSH). NPSH for cryogenic pumps is defined herein to mean, for a given fluid temperature, the difference between boiling pressure and the actual pressure. The same advantages are realized with the configuration of pump 149 shown in FIG. 5.
[0090] Yet another advantage of the pump configurations shown in FIGS. 3 through 5 is that the pump outlet is associated with the end of the pump that is opposite to the cold end, where the inlet is located. Cryogenic fluid, after being compressed, may have increased in temperature and it is desirable to keep the discharge conduits away from the inlet where heat transfer might cause additional vaporization of the fluid being induced through the pump inlet.
[0091] [0091]FIG. 4 illustrates a detailed enlarged section view of the second embodiment of the present system, in which LNG pump 48 is built into LNG tank assembly 30 . FIG. 4 illustrates suction line 31 in looped configuration to thereby provide a gas trap, as is common in the cryogenic and LNG art. Pump 48 is held in place against seal 47 formed in the end of sump 46 by bolts or some similar holding mechanism. Pump 48 can be separated from seal 47 and withdrawn by removing the securing bolts. The LNG from inner tank 42 (see FIG. 3) flows through suction line 31 into space 49 between sump 46 and the outer shell of pump 48 . The vacuum within sump space 44 (see FIG. 3) is maintained by sump space 44 being sealed by the exterior of sump 46 and sleeve 50 . Pump 48 can be withdrawn from the interior of sleeve 50 without disturbing the vacuum in space 44 (see FIG. 6). Sump 46 is sealed to sleeve 50 at junction 52 .
[0092] Built-in pump 48 operates in the following manner. When piston 54 retracts to the left, LNG is drawn through line 31 into first chamber 51 through check valve 63 . When piston 54 extends to the right, the LNG is pushed through check valve 53 located in piston 54 and into chamber space 55 between cylinder 58 and piston rod 56 . The diameter of piston rod 56 is sized so the volume of chamber space 55 is about half the volume of first chamber 51 . Therefore, half the volume of the liquid in chamber 51 will flow to chamber 55 and the remainder will be pushed out to the left through outlet line 64 and one-way check valve 66 (see FIG. 3). The pressure in chambers 51 and 55 will become equal to the discharge pressure as soon as piston 54 starts extending to the right.
[0093] When piston 54 retracts to the left again, more LNG will be drawn through line 31 into chamber 51 while at the same time the previously transferred LNG in chamber 55 will be discharged out through outlet line 64 . In other words, on each piston stroke, in either direction, about an equal amount of LNG is discharged. This is an advantage for smooth pump operation. It is also a significant advantage of this pump design that the one-way check valve (see check valve 66 in FIG. 3) can be located outside pump 48 on outlet line 64 , where it is accessible and easy to maintain. FIG. 4 also illustrates passageway 74 , which enables liquid that escapes past shaft seal 76 to return to sump 46 .
[0094] The pump shown in FIG. 4 will pump LNG to high pressure without inducing heat into storage tank assembly 30 , but if operating conditions are such that a longer holding time is demanded, an inducer feature similar to that shown in FIGS. 1 and 2 can be added. FIG. 5 illustrates a detailed enlarged section view of a third embodiment of the present system, which features an LNG pump built into the LNG tank in association with an inducer. It will be understood that FIG. 5 is illustrative only and would not be built precisely as shown. The narrow left end of sump 46 would have to be layered in order to enable the inducer of pump 148 to be withdrawn.
[0095] In the embodiment illustrated in FIG. 5, induction chamber 68 is attached to the inlet end of pump 148 thereby combining some of the novel features of pump 2 and pump 48 . The volume of induction chamber 68 is on the order of four times larger than chamber 51 , that is, the diameter of chamber 68 is twice that of chamber 51 . A smaller piston rod 59 is extended through the first bottom plug 60 and another piston 61 is attached to the end of rod 59 . This piston 61 has a pair of opposing check valves 70 and 72 , which act the same way as check valves 24 and 27 in pump 2 illustrated in FIGS. 1 and 2. Tube 69 connects the vapor space of tank 42 to main suction line 31 . Vapor is fed through restricting orifice 62 . This restricting orifice 62 acts the same way as metering valve 41 acts on pump 2 that is illustrated in FIG. 2. As before, by drawing vapor as well as liquid from inner tank 42 into induction chamber 68 through check valve 7 ′, the embodiment shown in FIG. 5 can greatly increase the holding time before boil off venting occurs. The optimum size for restriction of restriction 62 can be determined by employing an adjustable orifice. As previously disclosed, it is preferable to maintain a vapor fraction that is equal to or less than the maximum vapor fraction that allows condensation of substantially all of the vapor within the pump. Depending upon the scale of the system, restriction 62 can be sized to maintain a vapor fraction equal to or less than the maximum vapor fraction during normal operating conditions. Accordingly, a mixture of vapor and liquid can be drawn into induction chamber 68 , and by reciprocating piston 61 the vapor is condensed so that only liquid is drawn into first chamber 51
[0096] As an alternative embodiment, induction chamber 68 illustrated in FIG. 5 can be eliminated if the ratio between first chamber 51 and second chamber 55 is increased to more than 2:1. In that case, main suction line 31 and tube 69 , with restriction 62 , can be connected to sump 46 for inducing cryogenic fluid from sump 46 directly into chamber 51 through check valve 63 ′.
[0097] [0097]FIG. 6 illustrates a detail of sump 46 and sleeve 50 when LNG pump 48 has been separated from the LNG tank. After pump 48 has been withdrawn, sump 46 , with looped inlet 31 , and sleeve 50 , still remain in place within sump space 44 to preserve the vacuum between the outer tank and inner tank 42 of LNG tank assembly 30 . The end of sleeve 50 opposite sump 46 is sealed to the outer tank (not shown, but see FIG. 3) at seal 73 . Pressure seal 47 , against which pump 48 bears, when installed inside sleeve 50 and sump 46 , is also shown in FIG. 6.
[0098] LNG pumps 2 , 48 and 148 illustrated in FIGS. 1 to 6 inclusive are small and are intended primarily for use on vehicles for supplying fuel to an engine. It will be understood, however, that the pumps, in these configurations, can be used for cryogenic fluids other than LNG, including other fuels such as hydrogen. It will also be understood that the pumps can also be enlarged and used in other cryogenic applications such as liquid to compressed gas fuel stations (often known as LCNG fuel stations).
[0099] In FIG. 2, pump 2 is shown driven by a linear hydraulic motor. Compared to conventional mechanically driven reciprocating pumps, which are typically driven by a crankshaft at speeds of 200 to 500 RPM, a hydraulic drive allows the pump to be driven at much lower speeds. However, conventional LNG pumps, which are typically single acting, have not been known to be effective at low speeds for applications where there is a low NPSH.
[0100] In the applicant's own experiments, pump 48 illustrated in FIG. 4 was able to empty substantially all of the liquid from the storage tank at operating speeds between 5 and 30 cycles per minute. These results show that pump 48 is able to operate with zero or very near zero NPSH. Under the tested operating conditions, pump 48 operated at between 65 and 85 percent volumetric efficiency. Accordingly, whereas conventional single acting pumps are typically most effective at high operating speeds and with a NPSH significantly higher than zero, pump 48 demonstrates that it is possible to operate a reciprocating LNG pump at much lower speeds and with a NPSH of zero or very near zero.
[0101] Another advantage of hydraulically driven reciprocating pumps, compared to crankshaft driven pumps is that the piston travel is controllable to move at substantially a constant speed throughout the piston stroke. This reduces the generation of pressure pulses in the pipe leading from the pump discharge.
[0102] As will be apparent to those skilled in the art in light of the foregoing disclosure, many alterations and modifications are possible in the practice of the present invention without departing from the scope thereof. Accordingly, the scope of the present invention is to be construed in accordance with the substance defined by the following claims. | A medium and high pressure pump systems supplies a cryogenic fluid from a storage tank. The system comprises a pump that is operable to pump cryogenic liquid or a mixture of cryogenic liquid and vapor. The pump preferably comprises an inducer with at least two chambers and means for recycling excess fluid within the inducer instead of returning excess fluid to the storage tank. The reciprocating pump is preferably double acting such that fluid is discharged from the pump during both extension and retraction strokes. |
The present invention is a National Phase application of PCT/US2007/079605 and claims priority to U.S. application No. 60/850,705 filed 10 Oct. 2006.
FIELD OF THE INVENTION
The invention relates to a portable enclosure that contains potentially harmful substances during constructions or renovations.
BACKGROUND OF THE INVENTION
Enclosures and partitions, collectively enclosures, are often used to separate portions of a building or room during construction, renovation or maintenance projects. An enclosure serves as a barrier to dust, noise, light, odors, molds, mildews, etc. An enclosure separates the work area from areas that need to remain clean. For example, an enclosure can protect immuno-suppressed patients in a hospital from exposure to potentially harmful molds and bacteria that are released during building repair or maintenance. More simply, an enclosure can prevent construction debris and dust from entering a living space.
A simple enclosure includes a sheet of plastic or cloth that is nailed, screwed, stapled, taped or otherwise affixed floors, ceilings, and abutting walls. Alternatively, prior art teaches a spring-loaded jack system that secures the sheet in place without damage to floors, walls or ceilings. These simple enclosures can contain large particles during projects but, because of relatively large openings do little for very small particles, such as molds.
Large openings can permit the release into the air during and after a project of potentially dangerous amounts of airborne particulates, mold spores, bio-aerosols, gas phase pollutants and odors. By way of example, molds and fungi are often present in dark, humid areas, such as ceiling tiles, ventilation ducts or pipes, and can cause diseases such as aspergillosis. Aspergillosis includes allergic bronchopulmonary aspergillosis, pulmonary aspergilloma and invasive aspergillosis. Colonization of the respiratory tract is also common. People in a suppressed immunologic state are particularly susceptible. In such people, aspergillosis can result in death.
The Center for Disease Control and Prevention in Atlanta, Ga., USA has recognized that hospital construction and renovation projects pose particular risk to immuno-compromised patients, who may inhale airborne pollutants. Hospitals and other health care facilities have begun using portable enclosures that isolate construction, renovation and maintenance areas from patients. These units often include collapsible frames that support physical barriers. The enclosure should extend from the floor to the underside of the floor above. The unit should include gasketed doors with self-closing latching hardware and dampened walk-off mats both inside and outside of the construction area. The enclosure preferably includes a filter. The filter may include a high-efficiency particulate air (HEPA) filter maintains a negative air pressure in the enclosure relative to the rest of the area and simultaneously scrubs the air of contaminants. Alarms should signal any loss of negative pressure in the enclosure. In this manner, airborne hazards can be isolated from patients.
Present commercial enclosures include rigid enclosures and collapsible enclosures, and comprise one or more plastic sheets stretched around a frame. The sheets often comprise woven polyolefin. The frame may include plastic or metal tubing. Prior art frames can be difficult to disassemble or collapse, and workers often are reluctant to disassemble the enclosure once installed. Wheels may be provided to move the enclosure, whether assembled or collapsed, from place to place. The filter may be placed inside or outside the enclosure. Because the floor of the enclosure is typically no more than about 3×5 feet, placing the unit in the enclosure limits the usable space for the workers. Despite the desire to contain the air-borne particulates, present enclosures require workers to penetrate the physical barrier provided by the enclosure for electric cords, cables or other required facilities. Such penetrations typically by-pass the security measures manufactured into the enclosure. The penetrations permit contaminants to escape from the enclosure and so compromise patient health and safety.
A need exists for a portable enclosure suitable for hospital use that is easily collapsible and substantially completely isolates patients from construction, renovation or maintenance projects.
SUMMARY OF THE INVENTION
The present invention describes an enclosure for use as an air quality containment unit. The enclosure is useful as a temporary enclosure for construction, renovation and maintenance projects. The enclosure includes walls comprising one or more sheets stretched around a frame, a filter such as a high-efficiency particulate air (HEPA) filter for maintaining a negative air pressure in the unit, and at least one sealable orifice integrated with the wall. Optionally, the enclosure includes at least one electrical outlet accessible by a worker inside the enclosure.
The sealable orifice substantially prevents air from flowing into or out of the unit, but permits objects to pass through the sealable orifice. The sealable orifice includes a deformable gasket defining an opening. The gasket may comprise an elastomer, a closed-cell foam, or a gel pack. The opening may be defined, for example, by a plurality of elastomeric baffles, a plurality of gel packs circumscribed around the opening, or a throughbore.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a front view an enclosure of the present invention.
FIG. 2 is a rear view of the enclosure of FIG. 1 .
FIG. 3 is a perspective view of the enclosure of FIG. 1 .
FIG. 4 is a top view of the enclosure of FIG. 1 .
FIG. 5 is an exploded view of a sealable orifice of the present invention.
FIG. 6 is a perspective view of the sealable orifice of FIG. 5 .
FIG. 7 is a sectional view of the sealable orifice of FIG. 5 .
FIG. 8 shows flanges for an alternative embodiment.
FIG. 9 is a sectional view of another alternative embodiment.
DETAILED DESCRIPTION OF THE INVENTION
The enclosure includes air quality containment unit including a plurality of walls formed by a frame supporting at least one sheet or film. The frame and sheet define a space having a plurality of side walls and, optionally a top wall and a bottom wall. The enclosure should contain air borne particulates that are generated during construction, renovation or maintenance projects. To this end, the sheet comprises a material that is substantially impervious to air-borne particulates, such as dust or mold. The material may be, for example, an extruded or woven plastic such as polyvinylchloride or a spun polyolefin. The space should be large enough that a worker can perform the necessary operations within the enclosure. Practically, this means the space will have a floor that is usually at least about 60×100 cm and preferably at least about 100×150 cm. The height of the space should be at least sufficiently tall for a worker to kneel. One skilled in the art would appreciate that the actual size of the enclosure can vary.
One embodiment of the present invention is shown in FIG. 1 . FIG. 1 shows a front view of the air quality containment unit 1 . The unit 1 has a front wall 2 having a front width 5 . The front wall comprises an entrance flap 3 and a front panel 4 . The entrance flap 3 is capable of sealing engagement with the front panel 4 . Sealing engagement is facilitated by a sealing fastener 7 . The sealing fastener 7 may be continuous such as, for example, a zipper or Velcro® strips. Disengaging the entrance flap 3 from the front panel 4 defines an opening that is sufficiently large for a worker and his tools to enter and exit. Conveniently, the entrance flap 3 may have a window 6 integrated into the entrance flap. The window will typically comprise a clear vinyl.
FIG. 2 shows a back wall 21 having a back width 27 , and comprising an electrical channel 22 , a sealable orifice 23 , and filter 24 . The back width 27 is often the same dimensions as the front width 5 . Optionally, a pair of wheels 25 connected by an axle 26 facilitates portability by permitting the enclosure to be tipped and rolled to a new location. The unit 1 may also have at least one handle, not shown, that facilitates tipping the unit 1 onto the wheels 25 . The electrical channel 22 provides electrical power to the enclosure space without breaching containment. The electrical channel 22 includes at least one electrical outlet in the enclosure space that is electrically connected to an electrical plug on the outside of the space. The electrical channel 22 is sealed to prevent the escape of contaminants from the enclosure. Sealing may occur by any means including, for example, a gasket, sealant, welding, laminating, or molding in place. Connecting a source of electricity to the plug supplies electrical power to the outlet. The electrical outlet preferably comprises a power strip having a plurality of outlets.
The sealable orifice 23 permits a worker to pass any suitably sized object through the sealable orifice 23 without substantially breaking containment. The object could be temporarily passed through the sealable orifice 23 or placed there for the duration of the project. Prior art required a worker to unseal the entrance flap or pass the object above or below the enclosure. Prior art had even forced workers to cut the enclosure walls for electrical cords, air compressor cables, etc. Alternatively, workers had lifted the base of the enclosure from the floor. Either solution breached containment of the enclosure.
The sealable orifice 23 includes a gasket defining an opening. Of course, the enclosure may include a plurality of sealing orifices, and the sealing orifices may be distributed in the enclosure walls as needed. The opening can be of any convenient size. Absent any object, the gasket substantially prevents air from passing through the sealable orifice 23 . In the presence of an object, the gasket conforms to the exterior dimensions of the object thereby reducing air flow between the enclosure and the outside. Conveniently, a worker can pass a tool, cable, etc. through the sealable orifice 23 without opening the entrance flap. The gasket can be of any suitable design and may comprise an elastomer, closed-cell foam, gel pack, or combination thereof. Elastomer means any material capable of substantially elastic deformation with 100% strain. Elastomers include, for example, natural and synthetic rubbers and copolymers, silicones, and polyurethanes. Closed-cell foams are well-known in the art and comprise polymers such as, for example, polystyrene and substituted and non-substituted polyolefins including polyethylene, polypropylene, polyvinylchloride, and polytetraflouroethylene. Gel pack means any component comprising a deformable outer shell containing a fluid. Fluid means a gas or liquid, in particularly a liquid having a substantial viscous component, such as a gel or polymeric oil. Examples of a gel pack include vinyl shells containing a silicon oil, an aqueous solution, or polymeric gel.
FIG. 3 shows a side view of a unit 1 having a height 37 and a length 38 , and comprising an X-shaped frame 31 . The frame 31 includes top spars 32 and bottom spars 33 joined at a hub 34 . The hub 34 permits the spars to rotate relatively to each other so that the frame 31 collapses. Preferably, the front wall 2 collapses towards the back wall 21 so that the enclosure may be easily tipped onto the wheels 25 . The hub 34 may include a ratcheting mechanism that permits the front wall 2 and back wall 21 to be fixedly separated at various dimensions. Optionally, the frame may include a top member 35 and bottom member 36 to rigidize the frame 31 and improve stability. The members 35 , 36 may include a telescoping mechanism for collapsing and setting up the unit 1 .
FIG. 4 shows a top view of the unit 1 including side spars 41 . Side spars 41 may be rigid but may also be telescoping. Telescoping side spars 41 permit changing the widths 5 , 27 of the unit 1 . Telescoping side spars also permit greater portability of the enclosure. One skilled in the art would appreciate the mechanisms for including a telescoping feature into the side spars 41 . In this embodiment, a filter 24 is shown on the outside of the back wall 21 of the unit 1 . The filter may be connected to the enclosure via an air duct passing through an enclosure wall. Optionally, the filter 24 may be placed inside the enclosure 1 . Typically, the filter will be a HEPA filter. The filter will maintain a negative pressure in the air quality containment unit so that contaminated air does not escape the enclosure. If the filter is outside the enclosure, a sealable orifice may be fashioned to accommodate the air duct. Alternatively, an air duct connection may be fixed to an enclosure wall in the same manner as the electrical channel.
FIGS. 5-7 show one embodiment of the sealable orifice 23 . The sealable orifice 23 comprises a pair of flanges 51 , 52 sandwiching a deformable gasket 53 . The gasket defines an opening 54 that passes completely through the gasket 53 . The opening 54 is capable of substantially conforming to objects passing through the opening 54 . In operation, a wall 71 of the enclosure will define a hole 72 for receiving the gasket 53 . The flanges 51 , 52 are placed on either side of the wall 71 . Fasteners 73 secure the flanges 51 , 52 together through the wall 71 thereby securing the gasket 53 in the hole 72 . As shown, the fastener includes a bolt and nut. This embodiment permits replacement of a gasket 53 , which has deteriorated, and the flanges 51 , 52 reinforce of the hole 72 . Alternatively, the gasket may be permanently fixed to the wall such as by welding or adhesive, such that the sealable orifice consists essentially of the gasket.
An alternative fastener, as shown in FIG. 8 , includes a twist-and-lock system. The system comprises a first flange 51 with a plurality of prongs 81 and a second flange 52 defining a plurality of keyhole openings 82 . The prongs 81 include a shaft 87 that enlarges at the tip 86 . The keyhole opening 82 includes a slot 83 and an aperture 84 . The aperture 84 is larger than the slot 83 . The prongs 81 of the first flange 51 align with the apertures 84 of the second flange 52 so that the tip 86 extends beyond the aperture 84 . Extending the tip 86 beyond the aperture 84 may require a compressive force. Twisting the flanges 51 , 52 relative to each other locks the tip 86 against the second flange 52 through the slot 83 . Optionally, the prongs 81 may be reinforced to resist breakage during twisting. This fastener permits a sealable orifice to be installed or removed without tools. Conveniently, the prongs 81 may include a sharp tip 86 that can penetrate through the wall 71 by pressing the gasket 53 against the wall 71 .
The gasket 53 may define an opening 54 of any convenient size. The size of the opening 54 will depend on its intended use and the elasticity of the gasket 53 . For example, where the intended use consists of feeding small cables through the opening and the gasket comprises a relatively soft material such as 1 kg (2.2 pounds) weight polystyrene closed-cell foam, the opening may be formed by one or more slits cut through the gasket. Larger opening may be formed by a plurality of gel packs circumscribing the hole. As shown in FIG. 9 , the gasket 53 may even comprise a plurality of elastomeric baffles 91 . The baffles extend from a perimeter 92 . Each baffle 91 defines an opening 54 . The openings 54 permit passage of cords, tubing, wiring, and the like. The openings 54 of the baffles 91 may be in-line as shown or may be staggered to further restrict air ingress/egress.
Obviously, numerous modifications and variations of the present invention are possible. It is, therefore, to be understood that within the scope of the following claims, the invention may be practiced otherwise than as specifically described. While this invention has been described with respect to certain preferred embodiments, different variations, modifications, and additions to the invention will become evident to persons of ordinary skill in the art. All such modifications, variations, and additions are intended to be encompassed within the scope of this patent, which is limited only by the claims appended hereto. | The present invention describes an air quality containment unit for isolating a construction, renovation or maintenance project. The air quality containment unit contains dust, molds and other air-borne pollutants using a filter, such as a high-efficiency particulate air (HEPA) filter, to maintain a negative air pressure in the unit. The air quality containment unit includes at least one sealable orifice that allows workers to introduce, for example, an electrical cord into the unit without breaching containment. |
This application is a continuation of Ser. No. 10/187,381, filed Jul. 1, 2002, which is a continuation-in-part of Ser. No. 09/898,748 filed Jul. 3, 2001, now abandoned and claims priority from GB Application No. 0115986.2 filed Jun. 29, 2001, which is here incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to polymerisation process for forming light emitting polymers and networks thereof. The light emitting polymer may be used as a source of electroluminescence for use in displays for electronic products.
2. Prior Art
Modern consumer electronics require cheap, high-contrast displays with good power efficiency and low drive voltages. Particular applications include displays for mobile phones and hand-held computers.
Conventional displays comprise twisted nematic liquid crystal displays (TN-LCDs) with active matrix addressing and super-twisted nematic liquid crystal displays (STN-LCDs) with multiplex addressing. These however require intense back lighting which presents a heavy drain on power. The low intrinsic brightness of LCDs is believed to be due to high losses of light caused by the absorbing polarizers and filters which can result in external transmission efficiencies of as low as 4%.
SUMMARY OF THE INVENTION
The Applicants have now devised a new class of light emitting polymers. These can be employed in displays which offer the prospect of lower power consumption and/or higher brightness. The combination of these new light emitting polymers with existing LCD technology offers the possibility of low-cost, bright, portable displays with the benefits of simple manufacturing and enhanced power efficiency.
The light emitting polymer is obtainable by a polymerization process. The process involves the polymerization of reactive mesogens (e.g. in liquid crystal form) via photopolymerization of suitable end-groups of the mesogens.
According to one aspect of the present invention there is provided a process for forming a light emitting polymer comprising
photopolymerization of a reactive mesogen having the formula:
B—S-A-S—B (general formula 1)
wherein
A is a chromophore; S is a spacer; and B is an endgroup which is susceptible to photopolymerization.
The polymerisation typically results in a light emitting polymer comprising arrangements of chromophores (e.g. uniaxially aligned) spaced by a crosslinked polymer backbone. A typical process is shown schematically in FIG. 1 from which it may be seen that the polymerisation of reactive monomer 10 results in the formation of crosslinked polymer network 20 comprising crosslink 22 , polymer backbone 24 and spacer 26 elements.
Suitable chromophore (A) groups include fluorene, vinylenephenylene, anthracene, perylene and any derivatives thereof. Useful chromophores are described in A. Kraft, A. C. Grimsdale and A. B. Holmes, Angew. Chem. Int. Ed. Eng. [1998], 37, 402.
Suitable spacer (S) groups comprise organic chains, including e.g. flexible aliphatic, amine, ester or ether linkages. The chains may be saturated or unsaturated and be linear or branched. Aliphatic spacers are preferred. The presence of spacer groups aids the solubility and lowers the melting point of the light emitting polymer which assists the spin coating thereof.
Suitable endgroups are susceptible to photopolymerization (e.g. by a radical process using UV radiation, generally unpolarized). Preferably, the polymerization involves cyclopolymerization (i.e. the radical polymerization step results in formation of a cyclic entity).
A typical polymerization process involves exposure of a reactive mesogen of general formula 1 to UV radiation to form an initial radical having the general formula as shown below:
B—S-A-S—B• (general formula 2)
wherein A, S and B are as defined previously and B• is a radicalised endgroup which is capable, of reacting with another B endgroup (particularly to form a cyclic entity). The B• radicalised endgroup suitably comprises a bound radical such that the polymerisation process may be sterically controlled.
Suitable endgroups include dienes such as 1,4, 1,5 and 1,6 dienes. The diene functionalities may be separated by aliphatic linkages, but other inert linkages including ether and amine linkages may also be employed.
Methacrylate endgroups have been found to be less suitable than dienes because the high reactivity of the radicals formed after the photoinitiation step can result in a correspondingly high photodegradation rate. By contrast, it has been found that the photodegradation rate of light emitting polymers formed from dienes is much lower. The use of methacrylate endgroups also does not result in cyclopolymerization.
Where the endgroups are dienes the reaction typically involves cyclopolymerization by a sequential intramolecular and intermolecular propagation: A ring structure is formed first by reaction of the free radical with the second double bond of the diene group. A double ring is obtained by the cyclopolymerization which provides a particularly rigid backbone. The reaction is in general, sterically controlled.
Suitable reactive mesogens have the general formula:
wherein R has the general formula: X—S2-Y-Z
and wherein
X=O, CH 2 or NH and preferably X=O; S2=linear or branched alkyl or alkenyl chain optionally including a heteroatom (e.g. O, S or NH) and preferably S2=a linear alkyl chain; Y═O, CO 2 or S and preferably Y═CO 2 ; and Z=a diene (end-group) and preferably Z=a 1,4, 1,5 or 1,6 diene.
Exemplary reactive mesogens have the general formula:
wherein R is:
An exemplary reactive mesogen has the formula:
All of Compounds 3 to 6 exhibit a nematic phase with a clearing point (N—I) between 79 and 120° C.
Other suitable exemplary reactive mesogens have the general formula:
wherein n is from 2 to 10, preferably from 3 to 8 and as above, R has the general formula: X—S2-Y-Z
and wherein
X=O, CH 2 or NH and preferably X=O; S2=linear or branched alkyl or alkenyl chain optionally including a heteroatom (e.g. O, S or NH) and preferably S2=a linear alkyl chain; Y═O, CO 2 or S and preferably Y═CO 2 ; and Z=a diene (end-group) and preferably Z=a 1,4, 1,5 or 1,6 diene.
Suitably, R is as for any of Compounds 3 to 6, as shown above.
A particular class of exemplary reactive mesogens has the formula:
wherein:
n is from 2 to 10, preferably from 3 to 8; and m is from 4 to 12, preferably from 5 to 11.
Still further suitable exemplary reactive mesogens have the general formula:
wherein A=H or F
and wherein, as above, R has the general formula: X—S2-Y-Z
and wherein
X=O, CH 2 or NH and preferably X=O; S2=linear or branched alkyl or alkenyl chain optionally including a heteroatom (e.g. O, S or NH) and preferably S2=a linear alkyl chain; Y═O, CO 2 or S and preferably Y═CO 2 ; and Z=a diene (end-group) and preferably Z=a 1,4, 1,5 or 1,6 diene.
Suitably, R is as for any of Compounds 3 to 6, as shown above.
Particular exemplary reactive mesogens of this type have the formula:
In aspects, the photopolymerization process can be conducted at room temperature, thereby minimizing any possible thermal degradation of the reaction mesogen or polymer entities. Photopolymerization is also preferable to thermal polymerization because it allows subsequent sub-pixellation of the formed polymer by lithographic means.
Further steps may be conducted subsequent to the polymerization process including doping e.g. with photoactive dyes.
In preferred aspects, the polymerization process results in cross-linking e.g. to form a polymer network (e.g. an insoluble, cross-linked network).
Suitably, the light emitting polymer is a liquid crystal which can be aligned to emit polarised light. A suitable class of polymers is based on fluorene.
The reactive mesogen (monomer) typically has a molecular weight of from 400 to 2,000. Lower molecular weight monomers are preferred because their viscosity is also lower leading to enhanced spin coating characteristics and shorter annealing times which aids processing. The light emitting polymer typically has a molecular weight of above 4,000, typically 4,000 to 15,000.
The light emitting polymer (network) typically comprises from 5 to 50, preferably from 10 to 30 monomeric units.
According to another aspect of the present invention there is provided a process for applying a light emitting polymer to a surface comprising applying a reactive mesogen (as defined above) to said surface; and photopolymerizing said reactive mesogen in situ to form the light emitting polymer.
The light emitter polymers herein can in one aspect be used in a light emitter for a display comprising a photoalignment layer; and aligned on said photoalignment layer, the light emitting polymer.
The polymerization process herein can in one aspect be configured to form the light emitter by in situ polymerization of the reactive mesogens after their deposition on the photoalignment layer by any suitable deposition process including a spin-coating process
The photoalignment layer typically comprises a chromophore attached to a sidechain polymer backbone by a flexible spacer entity. Suitable chromophores include cinnamates or coumarins, including derivatives of 6 or 7-hydroxycoumarins. Suitable flexible spacers comprise unsaturated organic chains, including e.g. aliphatic, amine or ether linkages.
An exemplary photoalignment layer comprises the 7-hydroxycoumarin compound having the formula:
Other suitable materials for use in photoalignment layers are described in M. O'Neill and S. M. Kelly, J. Phys. D. Appl. Phys. [2000], 33, R67.
In aspects, the photoalignment layer is photocurable. This allows for flexibility in the angle in the azimuthal plane at which the light emitting polymer (e.g. as a liquid crystal) is alignable and thus flexibility in its polarization characteristics.
The photalignment layer may also be doped with a hole transport compound, that is to say a compound which enables transport of holes within the photoalignment layer, such as a triarylamine. Examples of suitable triarylamines include those described in C. H. Chen, J. Shi, C. W. Tang, Macromol Symp. [ 1997] 125, 1.
An exemplary hole transport compound is 4,4′,4″-tris[N-(1-napthyl)-N-phenyl-amino]triphenylamine which has the formula:
In aspects, the hole transport compound has a tetrahedral (pyramidal) shape which acts such as to controllably disrupt the alignment characteristics of the layer.
In one aspect, the photoalignment layer includes a copolymer incorporating both linear rod-like hole-transporting and photoactive side chains.
The light emitting polymer is aligned on the photoalignment layer. Suitably, the photoaligned polymer comprises uniaxially aligned chromophores. Typically polarization ratios of 30 to 40 are required, but with the use of a clean up polarizer ratios of 10 or more can be adequate for display uses.
In one aspect, the light emitter also comprises an organic light emitting diode (OLED) such as described in S. M. Kelly, Flat Panel Displays: Advanced Organic Materials, RSC Materials Monograph, ed. J. A. Connor, [2000]; C. H. Chen, J. Shi, C. W. Tang, Macromol Symp. [ 1997] 125, 1; R. H. Friend, R. W. Gymer, A. B. Holmes, J. H. Burroughes, R. N. Marks, C. Taliani, D. D. C. Bradley, D. A. Dos Santos, J. L. Bredas, M. Logdlund, W. R. Salaneck, Nature [ 1999] 397, 121; M. Grell, D. D. C. Bradley, Adv. Mater. [ 1999] 11, 895; N. C. Greenman, R. H. Friend Solid State Phys. [ 1995] 49,1.
OLEDs may be configured to provide polarized electroluminescence.
The light emitting polymer may be aligned by a range of methods including mechanical stretching, rubbing, and Langmuir-Blodgett deposition. Mechanical alignment methods can however lead to structural degradation. The use of rubbed polyimide is a suitable method for aligning the light emitting polymer especially in the liquid crystal state. However, standard polyimide alignment layers are insulators, giving rise to low charge injection for OLEDs.
The susceptibility to damage of the alignment layer during the alignment process can be reduced by the use of a non-contact photoalignment method. In such methods, illumination with polarized light introduces a surface anisotropy to the alignment layer and hence a preferred in-plane orientation to the overlying light emitting polymer (e.g. in liquid crystal form).
The aligned light emitting polymer is in one aspect in the form of an insoluble nematic polymer network. Cross-linking has been found to improve the photoluminescence properties.
M. O'Neill, S. M. Kelly J. Appl. Phys. D [ 2000] 33, R67 provides a review of photalignment materials and methods.
The light emitter herein may comprise additional layers such as carrier transport layers. The presence of an electron-transporting polymer layer (e.g. comprising an oxadiazole ring) has been found to increase electroluminescence.
An exemplary electron transporting polymer has the formula:
Pixellation of the light emitter may be achieved by selective photopatterning to produce red, green and blue pixels as desired. The pixels are typically rectangular in shape. The pixels typically have a size of from 1 to 50 μm, For microdisplays the pixel size is likely to be from 1 to 50 μm, preferably from 5 to 15 μm, such as from 8 to 10 μm. For other displays, larger pixel sizes e.g. 300 μm are more suitable.
In one preferred aspect, the pixels are arranged for polarized emission. Suitably, the pixels are of the same color but have their polarization direction in different orientations. To the naked eye this would look like one color, but when viewed through a polarizer some pixels would be bright and others less bright thereby giving an impression of 3D viewing when viewed with glasses having a different polarization for each eye.
The layers may also be doped with photoactive dyes. In aspects, the dye comprises a dichroic or pleachroic dye. Examples include anthraquinone dyes or tetralines, including those described in S. M. Kelly, Flat Panel Displays: Advanced Organic Materials, RSC Materials Monograph, ed. J. A. Connor, [2000]. Different dopant types can be used to obtain different pixel colors.
Pixel color can also be influenced by the choice of chromophore with different chromophores having more suitability as red, green or blue pixels, for example using suitably modified anthraquinone dyes.
Multicolor emitters are envisaged herein comprising arrangements or sequences of different pixel colors.
One suitable multicolor emitter comprises stripes of red, green and blue pixels having the same polarization state. This may be used as a sequential color backlight for a display which allows the sequential flashing of red, green and blue lights. Such backlights can be used in transmissive and reflective FLC displays where the FLC acts as a shutter for the flashing colored lights.
Another suitable multicolor emitter comprises a full color pixelated display in which the component pixels thereof have the same or different alignment.
Suitable multicolor emitters may be formed by a sequential ‘coat, selective cure, wash off’ process in which a first color emitter is applied to the aligned layer by a suitable coating process (e.g. spin coating). The coated first color emitter is then selectively cured only where pixels of that color are required. The residue (of uncured first color emitter) is then washed off. A second color emitter is then applied to the aligned layer, cured only where pixels of that color are required and the residue washed off. If desired, a third color may be applied by repeating the process for the third color.
The above process may be used to form a pixelated display such as for use in a color emissive display. This process is simpler than traditional printing (e.g. ink jet) methods of forming such displays.
There is also provided a backlight for a display comprising a power input; and a light emitter as described hereinbefore.
The backlight may be arranged for use with a liquid crystal display. In aspects, the backlight may be monochrome or multicolor.
There is further provided a display comprising a screen; and a light emitter or backlight as described hereinbefore.
The screen may have any suitable shape or configuration including flat or curved and may comprise any suitable material such as glass or a plastic polymer.
The light source of the present invention has been found to be particularly suitable for use with screens comprising plastic polymers such as polyethylene or polyethylene terephthalate (PET).
The display is suitable for use in consumer electronic goods such as mobile telephones, hand-held computers, watches and clocks and games machines.
There is further provided a security viewer (e.g. in kit form) comprising a light emitter as described herein in which the pixels are arranged for polarized emission; and view glasses having a different polarization for each eye.
There is further provided a method of forming a light emitter for a display comprising forming a photoalignment layer; and aligning a light emitting polymer on said photoalignment layer.
There is further provided a method of forming a light emitter for a display comprising forming a photoalignment layer; aligning a light emitting reactive mesogen on said photoalignment layer; and forming a light emitting polymer (network) by photopolymerisation of said reactive mesogen.
There is further provided a method of forming a multicolor emitter comprising applying a first color light emitter to the photoalignment layer; selectively curing said first color light emitter only where that color is required; washing off any residue of uncured first color emitter; and repeating the process for a second and any subsequent light color emitters.
All references herein are incorporated by reference in their entirety.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of systems according to the invention will now be described with reference to the accompanying experimental detail and drawings in which:
FIG. 1 is a schematic representation of a polymerization process herein;
FIG. 2 is a representation of a display device in accord with the present invention;
FIG. 3 is a representation of a backlight in accord with the present invention; and
FIG. 4 is a representation of a polarised sequential light emitting backlight in accord with the present invention.
FIGS. 5 to 12 show reaction schemes 1 to 8, respectively.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
General Experimental Details
Fluorene, 2-(tributylstanyl)thiophene, 4-(methoxyphenyl)boronic acid and the dienes were purchased from Aldrich and used as received. Reagent grade solvents were dried and purified as follows. N,N-Dimethylformamide (DMF) was dried over anhydrous P 2 O 5 and purified by distillation. Butanone and methanol were distilled and stored over 5 Å molecular sieves. Triethylamine was distilled over potassium hydroxide pellets and then stored over 5 Å molecular sieves. Dichloromethane was dried by distillation over phosphorus pentoxide and then stored over 5 Å molecular sieves. Chloroform was alumina-filtered to remove any residual ethanol and then stored over 5 Å molecular sieves. 1 H nuclear magnetic resonance (NMR) spectra were obtained using a JOEL JMN-GX270 FT nuclear resonance spectrometer. Infra-red (IR) spectra were recorded using a Perkin Elmer 783 infra-red spectrophotometer. Mass spectral data were obtained using a Finnegan MAT 1020 automated GC/MS. The purity of the reaction intermediates was checked using a CHROMPACK CP 9001 capillary gas chromatograph fitted with a 10 m CP-SIL 5CB capillary column. The purity of the final products was determined by high-performance liquid chromatography [HPLC] (5 □m, 25 cm×0.46 cm, ODS Microsorb column, methanol, >99%) and by gel-permeation chromatography [GPC] (5 □m, 30 cm×0.75 cm, 2× mixed D PL columns, calibrated using polystyrene standards [molecular weights=1000-4305000], toluene; no monomer present). The polymers were found to exhibit moderate to high M w values (10,000–30,000) and acceptable M w /M n values (1.5–3). The liquid crystalline transition temperatures were determined using an Olympus BH-2 polarising light microscope together with a Mettler FP52 heating stage and a Mettler FP5 temperature control unit. The thermal analysis of the photopolymerisable monomers (Compounds 3 to 6) and the mainchain polymer (Compound 7) was carried out by a Perkin-Elmer Perkin-Elmer DSC 7 differential scanning calorimeter in conjunction with a TAC 7/3 instrument controller. Purification of intermediates and products was mainly accomplished by column chromatography using silica gel 60 (200–400 mesh) or aluminium oxide (Activated, Brockman 1, ˜150 mesh). Dry flash column chromatography was carried out using silica gel H (Fluka, 5–40 μm). Electroluminescent materials were further purified by passing through a column consisting of a layer of basic alumina, a thin layer of activated charcoal, a layer of neutral alumina and a layer of Hi-Flo filter aid using DCM as an eluent. This was followed by recrystallisation from an ethanol-DCM mixture. At this stage, all glass-wear was thoroughly cleaned by rinsing with chromic acid followed by distilled water and then drying in an oven at 100° C. for 45 minutes. Purity of final products was normally confirmed by elemental analysis using a Fisons EA 1108 CHN apparatus.
Kev intermediate 1: 2,7-bis[5-(4-hydroxyphenyl)thien-2-yl]-9,9-dipropylfluorene was synthesised as shown in Reaction Scheme 1. Full details each step are now given:
9-Propylfluorene: A solution of n-Butyllithium (18.0 cm 3 , 10M solution in hexanes, 0.18 mol) was added slowly to a solution of fluorene (30.0 g, 0.18 mol) in THF (350 cm 3 ) at −50° C. The solution was stirred for 1 h at −75° C. and 1-bromopropane (23.0 g, 0.19 mol) was added slowly. The solution was allowed to warm to RT and then stirred for a further 1 h. Dilute hydrochloric acid (100 cm 3 , 20%) and water (100 cm 3 ) were added and the product extracted into diethyl ether (3×150 cm 3 ). The ethereal extracts were dried (MgSO 4 ) and concentrated to a pale yellow oil (37.5 g, yield 100%). Purity 100% (GC).
1 H NMR (CD 2 Cl 2 ) δ: 7.75 (2H, dd), 7.52 (2H, m), 7.32 (4H, m), 3.98 (1H, t), 1.95 (2H, m), 1.19 (2H, m), 0.85 (3H, t). IR (KBr pellet cm −1 ): 3070 (m), 2962 (s), 1450 (s), 1296 (w), 1189 (w), 1030 (w), 938 (w), 739 (s). MS (m/z): 208 (M + ), 178, 165 (M100), 139.
9,9-Dipropylfluorene: A solution of n-Butyllithium (29.0 cm 3 , 2.5M solution in hexanes, 0.073 mol) was added slowly to a solution of 9-propylfluorene (15.0 g, 0.072 mol) in THF at −50° C. The solution was stirred for 1 h at −75° C., 1-bromopropane (10.0 g, 0.092 mol) was added slowly and the temperature raised to RT after completion of the addition. After 18 h, dilute hydrochloric acid (20%, 100 cm 3 ) and water (100 cm 3 ) were added and the product extracted into diethyl ether (2□100 cm 3 ). The ethereal extracts were dried (MgSO 4 ) and concentrated to a pale brown oil which crystallised overnight at RT. The product was purified by recrystallisation from methanol to yield a white crystalline solid (14.5 g, yield 80%) mp 47–49° C. (Lit. 49–50° C. 19 ). Purity 100% (GC).
1 H NMR (CDCl 3 ) δ: 7.68 (2H, m), 7.31 (6H, m), 1.95 (4H, t), 0.65 (10H, m).IR (KBr pellet cm-1): 3068 (m), 2961 (s), 1449 (s), 1293 (w), 1 106 (w), 1027 (w), 775 (m), 736 (s), 637 (m). MS (m/z): 250 (M + ), 207 (M100), 191, 179, 165.
2,7-Dibromo-9,9-dipropylfluorene: Bromine (10.0 g, 0.063 mol) was added to a stirred solution of 9,9-dipropylfluorene (7.0 g, 0.028 mol) in chloroform (25 cm 3 ) and the solution purged with dry N 2 for 0.5 h. Chloroform (50 cm 3 ) was added and the solution washed with saturated sodium bisulphite solution (75 cm 3 ), water (75 cm 3 ), dried (MgSO 4 ) and concentrated to a pale yellow powder (11.3 g, yield 98%) mp 134–137° C.
1 H NMR (CDCl 3 ) δ: 7.51 (2H, d), 7.45 (4H, m), 1.90 (4H, t), 0.66 (10H, m). IR (KBr pellet cm −1 ): 2954 (s), 1574 (w), 1451 (s), 1416 (m), 1270 (w), 1238 (w), 1111 (w), 1057 (s), 1006 (w), 931 (w), 878 (m), 808 (s), 749 (m). MS (m/z): 409 (M + ), 365, 336, 323, 284, 269, 256, 248, 202, 189, 176 (M100), 163.
2,7-bis(Thien-2-yl)-9,9-dipropylfluorene: A mixture of 2,7-dibromo-9,9-dipropylfluorene (6.0 g, 0.015 mol), 2-(tributylstannyl)thiophene (13.0 g, 0.035 mol) and tetrakis(triphenylphosphine)-palladium (0) (0.3 g, 2.6×10 −4 mol) in DMF (30 cm 3 ) was heated at 90° C. for 24 h. DCM (200 cm 3 ) was added to the cooled reaction mixture and the solution washed with dilute hydrochloric acid (2□150 cm 3 , 20%), water (100 cm 3 ), dried (MgSO 4 ) and concentrated onto silica gel for purification by column chromatography [silica gel, DCM:hexane 1:1]. The compound was purified by recrystallisation from DCM: ethanol to yield light green crystals (4.3 g, yield 6 9%), mp 165–170° C. Purity 100% (GC).
1 H NMR (CDCl 3 ) δ: 7.67 (2H, d), 7.60 (2H, dd), 7.57 (2h, d), 7.39 (2H, dd), 7.29 (2H, dd), 7.11 (2H, dd), 2.01 (4H, m), 0.70 (10H, m). IR (KBr pellet cm −1 ): 2962 (m), 2934 (m), 2872 (m), 1467 (m), 1276 (w), 1210 (m), 1052 (w), 853 (m), 817 (s), 691 (s). MS (m/z): 414 (M + , M100), 371, 342, 329, 297, 207, 165.
2,7-bis(5-Bromothien-2-yl)-9,9-dipropylfluorene: N-Bromosuccinimide (2.1 g, 0.012 mol freshly purified by recrystallisation from water) was added slowly to a stirred solution of 2,7-bis(thien-2-yl)-9,9-dipropylfluorene (2.3 g, 5.55×10 −3 mol) in chloroform (25.0 cm 3 ) and glacial acetic acid (25.0 cm 3 ). The solution was heated under reflux for 1 h, DCM (100 cm 3 ) added to the cooled reaction mixture, washed with water (100 cm 3 ), HCl (150 cm 3 , 20%), saturated aqueous sodium bisulphite solution (50 cm 3 ), and dried (MgSO 4 ). The solvent was removed in vacuo and the product purified by recrystallisation from an ethanol-DCM mixture to yield yellow-green crystals (2.74 g, yield 86%). mp 160–165° C.
1 H NMR (CDCl 3 ) δ: 7.66 (2H, d), 7.49 (2H, dd), 7.46 (2H, d), 7.12 (2H, d), 7.05 (2H, d), 1.98 (4H, t), 0.69 (10H, m). IR (KBr pellet cm −1 ): 3481 (w), 2956 (s), 1468 (s), 1444 (m), 1206 (w), 1011 (w), 963 (w), 822 (m), 791 (s), 474 (w). MS (m/z): 572 (M + ), 529, 500, 487, 448, 433, 420, 407, 375, 250, 126.
2,7-bis[5-(4-Methoxyphenyl)thien-2-yl]-9,9-dipropylfluorene: A mixture of 2,7-bis(5-bromothien-2-yl)-9,9-dipropylfluorene (2.7 g, 4.7×10 −3 mol), 4-(methoxyphenyl)boronic acid (2.15 g, 0.014 mol), tetrakis(triphenylphosphine)palladium (0) (0.33 g, 2.9×10 −4 mol), sodium carbonate (3.0 g, 0.029 mol) and water (20 cm 3 ) in DME (100 cm 3 ) was heated under reflux for 24 h. More 4-(methoxyphenyl)boronic acid (1.0 g, 6.5×10 −3 mol) was added to the cooled reaction mixture, which was then heated under reflux for a further 24 h. DMF (20 cm 3 ) was added and the solution heated at 110° C. for 24 h, cooled and dilute hydrochloric acid (100 cm 3 , 20%) added. The cooled reaction mixture was extracted with diethyl ether (250 cm 3 ) and the combined ethereal extracts washed with water (100 cm 3 ), dried (MgSO 4 ), and concentrated onto silica gel to be purified by column chromatography [silica gel, DCM:hexane 1:1] and recrystallisation from an ethanol-DCM mixture to yield a green crystalline solid (1.86 g, yield 63%), Cr—N, 235° C.; N—I, 265° C.
1 H NMR (CD 2 Cl 2 ) δ: 7.71 (2H, dd), 7.61 (8H, m), 7.37 (2H, d), 7.24 (2H, d), 6.95 (4H, d), 3.84 (6H, s), 2.06 (4H, m), 0.71 (10H, m). IR (KBr pellet cm −1 ): 2961 (w), 1610 (m), 1561 (m), 1511 (s), 1474 (s), 1441 (m), 1281 (m), 1242 (s), 1170 (s), 1103 (m),829 (m), 790 (s). MS (m/z): 584 (M + -C 3 H 7 ), 569, 555, 539, 525, 511, 468, 313, 277 (M100), 248, 234. Elemental analysis. Calculated: wt % C=78.56%, H, 6.11%, S, 10.23%. Found: C, 78.64%, H, 6.14%, S, 10.25%
2,7-bis[5-(4-Hydroxyphenyl)thien-2-yl]-9,9-dipropylfluorene): A 1M solution of boron tribromide in chloroform (9 cm 3 , 9.0 mmol) was added dropwise to a stirred solution of 2,7-bis[5-(4-methoxyphenyl)thien-2-yl]-9,9-dipropylfluorene (1.3 g, 2.1×10 −3 mol) at 0° C. The temperature was allowed to rise to RT overnight and the solution added to ice-water (200 cm 3 ) with vigorous stirring. The product was extracted into diethyl ether (220 cm 3 ), washed with aqueous sodium carbonate (2M, 150 cm 3 ), dried (MgSO 4 ) and purified by column chromatography [silica gel DCM:diethyl ether:ethanol 40:4:1] to yield a green solid (1.2 g, yield 96%), Cr—I, 277° C.; N—I, 259° C.
1 H NMR (d-acetone) δ: 8.56 (2H, s), 7.83 (2H, dd), 7.79 (2H, d), 7.68 (2H, dd), 7.57 (4H, dd), 7.50 (2H, dd), 7.31 (2H, dd), 6.91 (4H, dd), 2.15 (4H, m), 0.69 (10H, m). IR (KBr pellet cm −1 ): 3443 (s, broad), 2961 (m), 1610 (m), 1512 (m), 1474 (m), 1243 (m), 1174 (m), 1110 (w), 831 (m), 799 (s). MS (m/z): 598 (M + ), 526, 419 (M100), 337.
Compound 3: 2,7-bis(5-{4-[5-(1-Vinyl-allyloxycarbonyl)pentyloxy]phenyl}thien-2-yl)-9,9-dipropylfluorene
The 1,3-pentadiene monomer (Compound 3) was synthesised as depicted in Reaction Scheme 2. Full details of each step are now given:
1,4-Pentadien-3-yl 6-bromohexanoate: A solution of 6-bromohexanoyl chloride (3.2 g, 0.026 mol) in DCM (30 cm 3 ) was added dropwise to a solution of 1,4-pentadien-3-ol (2.0 g, 0.024 mol) and triethylamine (2.4 g, 0.024 mol) in DCM (30 cm 3 ). The mixture was stirred for 1 h and washed with dilute hydrochloric acid (20%, 50 cm 3 ), saturated potassium carbonate solution (50 cm 3 ), water (50 cm 3 ) then dried (MgSO 4 ) and concentrated to a brown oil. The product was purified by dry flash chromatography [silica gel, DCM] to yield a pale yellow oil (4.7 g, yield 75%). Purity >95% (GC).
1 H NMR (CDCl 3 ) δ: 5.82 (2H, m), 5.72 (1H, m), 5.30 (2H, d), 5.27 (2H, d), 3.42 (2H, t), 2.37 (2H, t),1.93 (2H, m), 1.72 (2H, m), 1.54 (2H, m). IR (KBr pellet cm −1 ): 3095 (w), 1744 (s), 1418 (w), 1371 (w), 12521 (m), 1185 s), 983 (m), 934 (m). MS (m/z): 261 (M + ), 177, 67.
2,7-bis(5-{4-[5-(1-Vinyl-allyloxycarbonyl)pentyloxy]phenyl}thien-2-yl)-9,9-dipropylfluorene: A mixture of 2,7-bis[5-(4-hydroxyphenyl)thien-2-yl]-9,9-dipropylfluorene (0.6 g, 1.0×10 −3 mol), 1,4-pentadien-3-yl 5-bromohexanoate (0.7 g, 2.7×10 −3 mol) and potassium carbonate (0.5 g, 3.6×10 −3 mol) in acetonitrile (25 cm 3 ) was heated at 50° C. for 18 h. The mixture was then heated under reflux conditions for a further 20 h. Excess potassium carbonate was filtered off and precipitated product rinsed through with DCM (230 cm 3 ). The solution was concentrated onto silica gel for purification by column chromatography [silica gel, DCM:hexane 1:1 gradients to DCM] and recrystallisation from a DCM-ethanol mixture to yield a green-yellow solid (0.4 g, yield 40%), Cr—N, 92° C.; N—I, 108° C.
1 H NMR (CD 2 Cl 2 ) δ: 7.69 (2H, d), 7.58 (8H, m), 7.35 (2H, d), 7.22 (2H, d), 6.91 (4H, d), 5.83 (4H, m), 5.68 (2H, m), 5.29 (2H, t), 5.25 (2H, t), 5.21 (2H, t), 5.19 (2H, t), 3.99 (4H, t), 2.37 (4H, t), 2.04 (4H, m), 1.80 (4H, quint), 1.70 (4H, quint), 1.51 (4H, quint) 0.69 (10H, m). IR (KBr pellet cm −1 ): 2936 (m), 2873 (m), 1738 (s), 1608 (m), 1511 (m), 1473 (s), 1282 (m), 1249 (s), 1177 (s), 1110 (m), 982 (m), 928 (m), 829 (m), 798 (s). APCI-MS (m/z): 958 (M + ), 892 (M100). Elemental analysis. Calculated: wt % C=76.37; wt % H=6.93; wt % S=6.68. Found: wt % C=75.93; wt % H=6.95; wt % S=6.69.
Compound 4: 2,7-bis(5-{4-[5-(1-Allylbut-3-enyloxycarbonyl)pentyloxy]phenyl}thien-2-yl)-9,9-dipropylfluorene
The 1,3-heptadiene monomer (Compound 4) was synthesised as depicted in reaction Scheme 3. Full details of each step are now given:
1,6-Heptadien-5-yl 5-bromopentanoate: 5-Bromopentanoyl chloride (3.0 g, 0.015 mol) was added dropwise to 1,6-heptadien-4-ol (1.5 g, 0.013 mol) and triethylamine (1.4 g, 0.014 mol) in DCM (25 cm 3 ). The mixture was stirred for 2 h and washed with dilute hydrochloric acid (20%, 50 cm 3 ), saturated aqueous potassium carbonate solution (50 cm 3 ), water (50 cm 3 ) then dried (MgSO 4 ) and concentrated to a brown oil. The product was purified by dry flash chromatography [silica gel, DCM] to yield a pale yellow oil (1.7 g, yield 48%). Purity >92% (GC).
1 H NMR (CDCl 3 ) δ: 5.74 (2H, m), 5.08 (4H, m), 4.99 (1 H, m), 3.41 (2H, t), 2.31 (6H, m), 1.88 (2H, m), 1.76 (2H, m). IR (Film cm −1 ): 2952 (m), 1882 (w), 1734 (s), 1654 (m) 1563 (w), 1438 (m), 1255 (m), 1196 (s), 996 (m), 920 (s). MS (m/z): 275 (M + ), 245, 219, 191, 183, 163 (M100), 135, 95, 79.
2,7-bis(5-{4-[5-(1-Allylbut-3-enyloxycarbonyl)pentyloxy]phenyl}thien-2-yl)-9,9-dipropylfluorene: A mixture of 2,7-bis[5-(4-hydroxyphenyl)thien-2-yl]-9,9-dipropylfluorene (0.3 g, 1.0×10 −3 mol), 1,6-heptadienyl 6-bromohexanoate (0.7 g, 2.7×10 −3 mol) and potassium carbonate (0.5 g, 3.6×10 −3 mol) in acetonitrile (25 cm 3 ) was heated under reflux for 20 h. Excess potassium carbonate was filtered off and precipitated product rinsed through with DCM (230 cm 3 ). The solution was concentrated onto silica gel for purification by column chromatography [silica gel, DCM: hexane 1:1 gradients to DCM] and recrystallisation from a DCM-ethanol mixture to yield a green-yellow solid (0.21 g, yield 21%), Cr—I, 97° C., N—I, 94° C.
1 H NMR (CDCl 3 ) δ: 7.68 (2H, d), 7.60 (2H, dd), 7.58 (2H, d), 7.57 (2H, d), 7.33 (2H, d), 7.20 (2H, d), 6.91 (2H, d), 5.75 (4H, m), 5.08 (8H, m), 5.00 (2H, quint), 4.00 (4H, t), 2.33 (12H, m), 2.02 (4H, t), 1.82 (4H, quint), 1.71 (4H, quint), 1.53 (4H, m), 0.72 (10H, m). IR (KBr pellet cm −1 ): 3443 (s), 2955 (s), 1734 (s), 1643 (w), 1609 (m), 1512 (m), 1473 (s), 1249 (s), 1178 (s), 996 (m), 918 (m), 829 (m), 799 (s). APCI-MS (m/z): 1015 (M + , M100), 921. Elemental analysis. Calculated: wt % C=76.89; wt % H=7.35; wt % S=6.32%. Found: wt % C=76.96; wt % H=7.42; wt % S=6.23.
Compound 5: 2,7-bis(5-{4-[3-(1-Vinylallyloxycarbonyl)propyloxy]phenyl}thien-2-yl)-9,9-dipropylfluorene
The 1,3-pentadiene homologue (Compound 5) was synthesised as depicted in reaction Scheme 4. Full details of each step are now given:
4-Bromobutanoyl chloride: Oxalyl chloride (15.2 g, 0.12 mol) was added dropwise to a stirred solution of 4-bromobutanoic acid (10.0 g, 0.060 mol) and DMF (few drops) in chloroform (30 cm 3 ). The solution was stirred overnight under anhydrous conditions and concentrated to a pale brown oil which was filtered to remove solid impurities (11.0 g, yield 99%).
1,4-Pentadien-3-yl 4-bromobutanoate: 4-Bromobutanoyl chloride (3.0 g, 0.016 mol) was added dropwise to a solution of 1,4-pentadien-3-ol (1.3 g, 0.015 mol) and triethylamine (1.5 g, 0.015 mol) in DCM (30 cm 3 ). The solution was stirred for 2 h and washed with dilute hydrochloric acid (20%, 50 cm 3 ), saturated potassium carbonate solution (50 cm 3 ), water (50 cm 3 ) then dried (MgSO 4 ) and concentrated to a pale brown oil. The product was purified by dry flash chromatography [silica gel, DCM] to yield a pale yellow oil (1.8 g, yield 51%). Purity >85% (GC; decomposition on column).
1 H NMR (CDCl 3 ) δ: 5.83 (2H, m), 5.72 (1H, m), 5.27 (4H, m), 3.47 (2H, t), 2.55 (2H, t), 2.19 (2H, quint). IR (KBr pellet cm −1 ): 3096 (w), 2973 (w), 1740 (s), 1647 (w), 1419 (m), 1376 (m), 1198 (s), 1131 (s), 987 (s), 932 (s), 557 (w). MS (m/z) 217, 166, 152, 149, 125, 110, 84, 67 (M100).
2,7-bis(5-{4-[3-(1-Vinylallyloxycarbonyl)propyloxy]phenyl}thien-2-yl)-9,9-dipropylfluorene: A mixture of 2,7-bis[5-(4-hydroxyphenyl)thien-2-yl]-9,9-dipropylfluorene (0.25 g, 4.2×10 −4 mol), 1,4-pentadien-3-yl 4-bromobutanoate (0.40 g, 1.7×10 −3 mol) and potassium carbonate (0.20 g, 1.4×10 −3 mol) in DMF (10 cm 3 ) was heated under reflux for 4 h. The cooled solution was filtered, rinsed through with DCM (3×20 cm 3 ) and concentrated to a pale green oil which was purified by column chromatography [silica gel, DCM:hexane 2:1] followed by recrystallisation from ethanol:DCM to yield a green-yellow powder (0.20 g, yield 53%), Cr—N, 92° C.; N—I, 116° C.
1 H NMR (CDCl 3 ) δ: 7.61 (10H, m), 7.33 (2H, d), 7.20 (2H, d), 6.92 (4H, d), 5.85 (4H, m), 5.74 (2H, m), 5.32 (4H, d, J=17 Hz), 5.24 (4H, d, J=10 Hz), 4.06 (4H, t), 2.56 (4H, t), 2.16 (4H, quint), 2.05 (4H, t), 0.72 (10H, m). IR (KBr pellet cm −1 ): 3449 (m), 2960 (m), 1738 (s), 1609 (m), 1512 (m), 1473 (s), 1380 (w), 1249 (s), 1174 (s), 1051 (m), 936 (m), 830 (m), 799 (s). APCI-MS (m/z): 903 (M + ), 837 (M100), 772. Elemental analysis. Calculated: wt % C=75.80; wt % H=6.47; wt % S=7.10. Found: wt % C=76.13; wt % H=6.48%, wt % S=6.91.
Compound 6: 2,7-bis{5-[4-(8-Diallylaminooctyloxy)phenyl]-thien-2-yl}-9,9-dipropylfluorene
The method of preparation of the N,N-diallylamine monomer (Compound 6) is shown in reaction Scheme 5. Full details of each step are now given:
8-Diallylaminooctan-1-ol. A mixture of 8-bromooctan-1-ol (10.0 g, 0.048 mol), diallylamine (4.85 g, 0.050 mol) and potassium carbonate (7.0 g, 0.051 mol) in butanone (100 cm 3 ) was heated under reflux for 18 h. Excess potassium carbonate was filtered off and the solution concentrated to a colourless oil. The product was purified by dry flash chromatography [silica gel, DCM:ethanol 4:1]. (10.0 g, yield 93%)
1 H NMR (CDCl 3 ) δ: 5.86 (2H, d), 5.14 (4H, m), 3.71 (4H, quart), 3.63 (4H, t), 3.09 (4H, d), 1.56 (4H, m), 1.45 (2H, quint), 1.30 (6H,m). IR (KBr pellet cm −1 ): 3344 (s), 2936 (s), 1453 (w), 1054 (m), 998 (m), 921 (m). MS (m/z): 225 (M + ), 198, 184, 166, 152, 138, 124, 110 (M100), 81.
Toluene-4-sulphonic acid 8-diallylaminooctyl ester. 4-Toluene-sulphonyl chloride (12.5 g, 0.066 mol) was added slowly to a stirred solution of 8-diallylaminooctan-1-ol (10.0 g, 0.044 mol) and pyridine (7.0 g, 0.088 mol) in chloroform (100 cm 3 ) at 0° C. After 24 h, water (100 cm 3 ) was added and the solution washed with dilute hydrochloric acid (20%, 100 cm 3 ), sodium carbonate solution (100 cm 3 ), water (100 cm 3 ), dried (MgSO 4 ) and concentrated to a yellow oil which was purified by column chromatography [silica gel, 4% diethyl ether in hexane eluting to DCM:ethanol 10:1] to yield the desired product (6.7 g, yield 40%).
1 H NMR (CDCl 3 ) δ: 7.78 (2H, d), 7.34 (2H, d), 5.84 (2H, m), 5.13 (4H, m), 4.01 (2H, t), 3.41 (4H, d), 2.45 (3H, s), 2.39 (2H, t), 1.63 (2H, quint), 1.42 (2H, quint), 1.30 (2H, quint), 1.23 (6H, m). IR (KBr pellet cm −1 ): 3454 (w), 2957 (m), 1453 (s), 1402 (m), 1287 (m), 1159 (w), 1061 (m), 914 (w), 878 (m), 808 (s), 448 (m). MS (m/z): 380 (M + ), 364, 352, 338, 224, 110 (M100), 91, 79, 66.
2,7-bis{5-[4-(8-Diallylaminooctyloxy)phenyl]-thien-2-yl}-9,9-dipropylfluorene: A mixture of 2,7-bis[5-(4-hydroxyphenyl)thien-2-yl]-9,9-dipropylfluorene (0.5 g, 8.4×10 −4 mol), toluene-4-sulphonic acid-8-diallylaminooctyl ester (0.8 g, 2.1×10 −3 mol) and potassium carbonate (0.3 g, 2.2×10 −3 mol) in butanone (30 cm 3 ) was heated under reflux for 24 h. Excess potassium carbonate was filtered off and rinsed with DCM (3×30 cm 3 ). The solution was concentrated onto silica gel for purification by column chromatography [silica gel, DCM:hexane 2:1 eluting to DCM:ethanol 4:1]. The product was obtained as a yellow-green glass (0.35 g, yield 41%), N—I, 95° C.
1 H NMR (CDCl 3 ) δ: 7.67 (2H, d), 7.58 (8H, m), 7.34 (2H, d), 7.20 (2H, d), 6.92 (4H, d), 5.94 (4H, m), 5.25 (8H, m), 3.99 (4H, t), 3.22 (8H, d), 2.02 (4H, t), 1.80 (4H, quint), 1.56 (4H, quint), 1.47 (4H, quint), 1.35 (12H, m), 0.71 (10H, m). IR (KBr pellet cm −1 ): 3437 (s), (2934 (s), 1609 (s), 1512 (s), 1472 (s), 1283 (m), 1249 (s), 1179 (s), 1031 (w), 918 (w), 829 (m), 798 (s). APCI-MS (m/z): 1014 (M + , M100), 973. Elemental analysis. Calculated: wt % C=79.40; wt % H=8.35; wt % N=2.76; wt % S=6.33. Found: wt % C=79.33; wt % H=8.29; wt % N=2.88; wt % S=6.17.
Compound 7: poly(phenylene-1,3,4-oxadiazole-phenylene-hexafluoropropylene)
The electron-transporting polymer (Compound 7) was prepared according to a literature method described in Li, X.-C.; Kraft, A.; Cervini, R.; Spencer, G. C. W.; Cacialli, F.; Friend, R. H.; Gruener, J.; Holmes, A. B.; de Mello, J. C.; Moratti, S. C. Mat. Res. Symp. Proc. 1996, 413 13.
In more detail the preparation details were as follows: A solution of 4,4′-(hexafluoroisopropylidine)bis(benzoic acid) (2.54 g, 6.48×10 −3 mol) and hydrazine sulphate (0.84 g, 6.48×10 −3 mol) in Eaton's reagent (25 cm 3 ) was heated under reflux for 18 h. The cooled solution was added to brine (300 cm 3 ) and the product extracted into chloroform (8×200 cm 3 ). The organic extracts were combined, dried (MgSO 4 ) and the solvent removed under reduced pressure to yield the crude product which was purified by dissolving in a minimum volume of chloroform and precipitating by dropwise addition to methanol (1000 cm 3 ). The precipitate was filtered off and washed with hot water before being dried in vacuo. The precipitation was repeated a further three times washing with methanol each time. The product was then dissolved in chloroform and passed through a microfilter (0.45 μm). The pure product was then precipitated in methanol (500 cm 3 ) and the methanol removed under reduced pressure to yield a white fibrous solid which was dried in vacuo. Yield 1.26 g (50%).
1 H NMR (CDCl 3 ) δ H : 8.19 (4H/repeat unit, d), 7.61 (4H/repeat unit, d). IR ν max /cm −1 : 3488 (m), 1621 (m), 1553 (m), 1502 (s), 1421 (m), 1329 (m), 1255 (s), 1211 (s), 1176 (s), 1140 (s), 1073 (m), 1020 (m), 969 (m), 929 (m), 840 (m), 751 (m), 723 (s). GPC: M w :M n =258211:101054.
An alternative electron-transport copolymer is prepared according to the method described in Xiao-Chang Li et al J. Chem. Soc. Chem. Commun., 1995, 2211.
In more detail the preparation details were as follows: Terephthaloyl chloride (0.50 g, 2.46×10 −3 mol) was added to hydrazine hydrate (50 cm 3 ) at room temperature and the mixture stirred for 2 h. The precipitate was filtered off, washed with water (100 cm 3 ) and dried in vacuo. The crude hydrazide (0.25 g, 1.3×10 −3 mol), 4,4′-(hexafluoroisopropylidine)bis(benzoic acid) (2.50 g, 6.4×10 −3 mol) and hydrazine sulphate (0.66 g, 5.2×10 −3 mol) were added to Eaton's reagent and the resultant mixture heated at 100° C. for 24 h. The reaction mixture was added to water (300 cm 3 ) and the product extracted into chloroform (3×300 cm 3 ). The organic extracts were combined, dried (MgSO 4 ) and the solvent removed in vacuo before re-dissolving the product in the minimum volume of chloroform. The solution was added dropwise to methanol (900 cm 3 ) to give a white precipitate which was filtered off and dried in vacuo. The precipitation was repeated twice before dissolving the product in chloroform and passing through a microfilter (0.45 μm) into methanol (500 cm 3 ). The methanol was removed under reduced pressure and the product dried in vacuo. Yield 1.1 g (41%)
1 H NMR (CDCl 3 ) δ H : 8.18 (dd, 4H/repeat unit), 7.60 (dd, 4H/repeat unit). IR ν max /cm −1 : 3411 (w), 2366 (w), 1501 (m), 1261 (s), 1211 (s), 1176 (s), 1140 (m), 1072 (m), 1021 (w), 968 (m), 931 (w), 840 (m), 722 (m). GPC: M w :M n =20572:8320.
Key intermediate 2: 9,9diethyl-2,7-bis(4-hydroxybiphenyl-4′-yl)fluorene was synthesised as shown in Reaction Scheme 7. Full details of each step are now given:
9-Ethylfluorene: A solution of n-butyllithium (79.52 cm 3 , 0.2168 mol. 2.5M in hexane) was added slowly to a solution of fluorene (30.00 g, 0.1807 mol) in THF (300 cm 3 ) at −70° C. The solution was stirred for 1 hour at −75° C. and 1-bromoethane (17.59 cm 3 , 0.2349 mol) was added slowly. The solution was allowed to warm to room temperature and then stirred overnight. Dilute hydrochloric acid (200 ml, 20%) was added to the reaction mixture and stirred for a further 10 minutes. Water (250 cm 3 ) was added and the product extracted into diethyl ether (3×300 cm 3 ). The combined organic extracts were dried (MgSO 4 ) and the solvent removed on a rotary evaporator. The resulting oil was purified by distillation to yield a pale yellow oil (25.00 g, 71%, b.pt.-150° C. @ 1 mbar Hg).
1 H NMR (DMSO) δ: 7.70 (2H, m), 7.50 (2H, m), 7.30 (4H, m), 4.00 (1H, t), 2.02 (2H, quart), 0.31 (3H, t). IR ν max /cm −1 : 3072 (m), 2971, 1618, 1453, 1380, 1187, 759, 734. MS m/z: 170 (M + ), 94, 82, 69.
9,9-Diethylfluorene: A solution of n-butyllithium (77.34 cm 3 , 0.1934 mol, 2.5M in hexane) was added slowly to a solution of 9-ethylfluorene (25.00 g, 0.1289 mol) in THF (250 cm 3 ) at −70° C. The solution was stirred for 1 hour at −75° C. and 1-bromoethane (17.59 cm 3 , 0.1934 mol) was added slowly. The solution was allowed to warm to room temperature and then stirred overnight. Dilute hydrochloric acid (200 cm 3 , 20%) was added to the reaction mixture and stirred for a further 10 minutes. Water (250 cm 3 ) was added and the product extracted into diethyl ether (3×300 cm 3 ). The combined organic extracts were dried (MgSO 4 ) and the solvent removed on a rotary evaporator. The resulting oil was cooled to room temperature and recrystallised with ethanol to yield white crystals (19.50 g, 68%, m.pt. 60–62° C.).
1 H NMR (DMSO) δ: 7.76 (2H, m), 7.51 (2H, m), 7.35 (4H, m), 1.51 (4H, quart), 0.30 (6H, t), IR ν max /cm −1 : 3069, 2972, 1612, 1448, 1310, 761, 736. MS m/z: 222 (M + ), 193, 152, 94, 82, 75.
2,7-Dibromo-9,9-diethylfluorene: Bromine (13.47 cm 3 , 0.2568 mol) was added to a stirred solution of 9,9-diethylfluorene (19.00 g, 0.0856 mol) in DCM (250 cm 3 ). The HBr gas evolved was passed through a scrubbing solution of NaOH (1.5M). The reaction mixture was stirred for 4 hours. The reaction mixture was washed with sodium metabisulphite solution and extracted into diethyl ether (3×300 cm 3 ). The combined organic extracts were dried and the solvent removed on a rotary evaporator. The crude product was recrystallised from ethanol to yield a white crystalline solid (20.00 g, 61%, m.pt. 152–154° C.).
1 H NMR (DMSO) δ: 7.52 (2H, m), 7.45 (4H, m), 1.99 (4H, quart), 0.31 (6H, t). IR ν max /cm −1 : 2966, 1599, 1453, 1418, 1058, 772, 734. MS m/z: 380 (M + ), 351, 272, 220, 189, 176, 165, 94, 87, 75.
4-Bromo-4′-octyloxybiphenyl: A mixture of 4-bromo-4′-hydroxybiphenyl (50.00 g, 0.2008 mol), 1-bromooctane (50.38 g, 0.2610 mol), potassium carbonate (47.11 g, 0.3414 mol) and butanone (500 cm 3 ) was heated under reflux overnight. The cooled mixture was filtered and the solvent removed on a rotary evaporator. The crude solid was recrystallised from ethanol to yield a white crystalline solid (47.30 g, 66%, m.pt. 120° C.).
1 H NMR (DMSO) δ: 7.46 (6H, m), 6.95 (2H, m), 3.99 (2H, t), 1.80 (2H, quint), 1.38 (10H, m), 0.88 (3H, t). IR ν max /cm −1 : 2927, 2860, 1608, 1481, 1290, 1259, 844. MS m/z: 362 (M + ), 250, 221, 195, 182, 152, 139, 115, 89, 76, 69.
4-Octyloxybiphenyl-4′-yl boronic acid: A solution of n-butylithium (50.97 cm 3 , 0.1274. mol, 2.5M in hexane) was added dropwise to a cooled (−78° C.) stirred solution of 4-bromo-4′-octyloxybiphenyl (40.00 g, 0.1108 mol) in THF (400 cm 3 ). After 1 h, trimethyl borate (23.05 g, 0.2216 mol) was added dropwise to the reaction mixture maintaining a temperature of −78° C. The reaction mixture was allowed to warm to room temperature overnight. 20% hydrochloric acid (350 cm 3 ) was added and the resultant mixture stirred for 1 h. The product was extracted into diethyl ether (3×300 cm 3 ). The combined organic layers were washed with water (300 cm 3 ), dried (MgSO 4 ), filtered and the filtrate evaporated down under partially reduced pressure. The crude product was stirred with hexane for 30 minutes and filtered off to yield a white powder (26.20 g, 73%, m.pt. 134–136° C.).
1 H NMR (DMSO) δ: 8.04 (2H, s), 7.84 (2H, m), 7.57 (4H, m), 7.00 (2H, m), 3.99 (2H, t), 1.74 (2H, quint), 1.35 (10H, m), 0.85 (3H, t). IR ν max /cm −1 : 2933, 2860, 1608, 1473, 1286, 1258, 818. MS m/z: 326 (M + ), 214, 196, 186, 170, 157, 128, 115, 77, 63
9,9-Diethyl-2,7-bis(4-octyloxybiphenyl-4′-yl)fluorene: Tetrakis(triphenylphosphine)palladium(0) (0.70 g, 0.0006 mol) was added to a stirred solution of 2,7-dibromo-9,9-diethylfluorene (4) (2.33 g, 0.0061 mol), 4-octyloxybiphenyl-4′-yl boronic acid (5.00 g, 0.0153 mol), 20% sodium carbonate solution (100 cm 3 ) and 1,2-dimethoxyethane (150 cm 3 ). The reaction mixture was heated under reflux overnight. Water (300 cm 3 ) was added to the cooled reaction mixture and the product extracted into DCM (3×300 cm 3 ). The combined organic extracts were washed with brine (2×150 cm 3 ), dried (MgSO 4) ), filtered and the filtrate evaporated down under partially reduced pressure. The residue was purified by column chromatography on silica gel using DCM and hexane (30:70) as eluent and recrystallisation from ethanol and DCM to yield a white crystalline solid (3.10 g, 65%, m.pt. 146° C.).
1 H NMR (DMSO) δ: 7.77 (6H, m), 7.63 (12H, m), 7.00 (4H, m), 4.01 (4H, t), 2.13 (4H, quart), 1.82 (4H, quint), 1.40 (20H, m), 0.89 (6H, t), 0.43 (6H, t). IR ν max /cm −1 : 3024, 2921, 2853, 1609, 1501, 1463, 1251, 808. MS m/z: 782 (M + ), 669, 514, 485, 279, 145, 121, 107, 83, 71. CHN analysis: % Expected C, (87.42%), H, (8.49%). % Found C, (87.66%), H, (8.56%).
9,9-Diethyl-2,7-bis(4-hydroxybiphenyl-4′-yl)fluorene: Boron tribromide (99.9%, 1.05 cm 3 , 0.0111 mol) in DCM (10 ml) was added dropwise to a cooled (0° C.) stirred solution of 9,9-diethyl-2,7-bis(4-octyloxybiphenyl-4′-yl)fluorene (2.90 g, 0.0037 mol) in DCM (100 cm 3 ). The reaction mixture was stirred at room temperature overnight, then poured onto an ice/water mixture (50 g) and stirred (30 minutes). The crude product was purified by column chromatography on silica gel with a mixture of ethyl acetate and hexane (30:70) as the eluent and recrystallisation from ethanol to yield a white powder (0.83 g, 40%, m.pt. >300° C.).
1 H NMR (DMSO) δ: 9.09 (2H, OH), 7.77 (6H, m), 7.64 (8H, m), 7.51 (4H, m), 6.94 (4H, m), 1.19 (4H, m), 0.42 (6H, t). IR ν max /cm −1 : 1608, 1500, 1463, 1244, 1173, 811. MS m/z: 558 (M + ), 529, 514, 313, 279, 257, 115, 77, 65.
Compound 8: 9,9-Diethyl-2,7-bis{4-[5-(1-vinyl-allyloxycarbonyl)pentyloxy]biphenyl-4′-yl}fluorene
Compound 8 was synthesised as follows:
A mixture of 9,9-diethyl-2,7-bis(4-hydroxybiphenyl-4′-yl)fluorene (0.83 g, 0.0015 mol), 1,4-pentadienyl-3-yl 6-bromohexanoate (0.97 g, 0.0037 mol), potassium carbonate (0.62 g, 0.0045 mol) and DMF (25 cm 3 ) was heated under reflux overnight. The cooled reaction mixture was added to water (500 cm 3 ) and then extracted with DCM (3×50 cm 3 ). The combined organic extracts were washed with water (250 cm 3 ), dried (MgSO 4 ) and the filtrate evaporated down under partially reduced pressure. The crude product was purified by column chromatography using silica gel using a mixture of DCM and hexane (80:20) as the eluent and recrystallisation from DCM and ethanol to yield a white crystalline solid (0.2 g, 22%).
1 H NMR (CDCl 3 ) δ: 7.78 (6H, m), 7.62 (12H, m), 7.00 (4H, m), 5.85 (4H, m), 5.74 (4H, m), 5.27 (4H, m), 4.03 (4H, t), 2.42 (4H, t), 2.14 (4H, quart), 1.85 (4H, m), 1.74 (4H, m), 1.25 (4H, q), 0.43 (3H, t). IR ν max /cm −1 : 3028, 2922, 2870, 1734, 1606, 1500, 1464, 1246, 1176, 812. CHN analysis: % Expected C, (82.32%), H, (7.24%). % Found C, (81.59%), H, (6.93%).
Compounds 9–15: Compounds 9 to 15, comprising the 2,7-bis{ω-[5-(1-vinyl-allyloxycarbonyl)alkoxy]-4′-biphenyl}9,9-dialkylfluorenes compounds of Table 1 were prepared analogously to Compound 8.
n
m
Compound 9
3
5
Compound 10
4
5
Compound 11
5
5
Compound 12
6
5
Compound 13
8
5
Compound 14
8
7
Compound 15
8
11
All of Compounds 8 to 15 exhibit a nematic phase with a clearing point (N—I) between 58 and 143° C.
Compound 16: 4,7-bis{4-[(S)-3,7-Dimethyl-oct-6-enyloxy]phenyl}-2,1,3-benzothiadozole
Compound 16 was synthesised as depicted in Reaction Scheme 8. Full details of each step follows:
4,7-Dibromo-2,1,3-benzothiadozole: Bromine (52.8 g, 0.33 mol) was added to a solution of 2,1,3-benzothiadozole (8.1 g, 0.032 mol) in hydrobromic acid (47%, 100 cm 3 ) and the resultant solution was heated under reflux for 2.5 h. The cooled reaction mixture reaction mixture was filtered and the solid product washed with water (200 cm 3 ) and sucked dry. The raw product was purified by recrystallisation from ethanol to yield 21.0 g (65%) of the desired product.
1-Bromo-4-[(S)-3,7-dimethyloct-6-enyloxy]benzene: A mixture of 4-bromophenol (34.6 g, 0.20 mol), (S)-(+)-citronellyl bromide (50 g, 0.023 mol) and potassium carbonate (45 g, 0.33 mol) in butanone (500 cm 3 ) was heated under reflux overnight. The cooled reaction mixture was filtered and the filtrate concentrated under reduced pressure. The crude product was purified by fractional distillation to yield 42.3 g (68.2%) of the desired product.
4-[(S)-3,7-Dimethyloct-6-enyloxy]phenyl boronic acid: 2.5M n-Butylithium in hexanes (49.3 cm 3 , 0.12 mol) was added dropwise to a cooled (−78° C.) solution of 1-bromo-4-[(S)-3,7-dimethyloct-6-enyloxy]benzene (35 g, 0.11 mol) in tetrahydrofuran (350 cm 3 ). The resultant solution was stirred at this temperature for 1 h and then trimethyl borate (23.8 g, 0.23mol) was added dropwise to the mixture while maintaining the temperature at −78° C. 20% hydrochloric acid (250 cm 3 ) was added and the resultant mixture was stirred for 1 h and then extracted into diethyl ether (2×200 cm 3 ). The combined organic layers were washed with water (2×100 cm 3 ) and dried (MgSO 4 ). After filtration the solvent was removed under reduce pressure to yield 20.35 g (65%) of the desired product.
4,7-bis{4-[(S)-3,7-Dimethyl-oct-6-enyloxy]phenyl}-2,1,3-benzothiadozole: A mixture of tetrakis(triphenylphosphine)palladium(0) (0.8 g, 0.70×10 −3 mol), 4,7-dibromo-2,1,3-benzothiadozole (2) (2 g, 6.75×10 −3 mol), 4-[(S)-3,7-dimethyloct-6-enyloxy]phenyl boronic acid (4.66 g, 1.70×10 −2 mol), 2M sodium carbonate solution (50 cm ) and 1,2-dimethoxyethane (150 cm 3 ). The reaction mixture was heated under reflux overnight. The cooled reaction mixture was extracted with dichloromethane (2×150 cm 3 ) and the combined organic layers were washed with brine (2×100 cm 3 ) and dried (MgSO 4 ). After filtration the solvent was removed under reduced pressure and the residue was purified by column chromatography [silica gel, dichloromethane:hexane 1:4] followed by recrystallisation from ethanol to yield 3.2 g (79.5%) of the desired product.
4,7-bis(4-Hydroxyphenyl)-2,1,3-benzothiadozole: Boron tribromide (1.51 cm 3 , 1.61×10 −2 mol) was added dropwise to a cooled (0° C.) stirred solution of 2,5-bis{4-[(S)-3,7-dimethyl-oct-6-enyloxy]phenyl}-2,1,3-benzothiadozole (4.0 g, 7.40×10 −3 mol) in dichloromethane (100 cm 3 ). The reaction mixture was stirred at room temperature overnight, then poured onto an ice/water mixture (200 g) and stirred (30 min). The desired product was precipitated and it was filtered off and sucked dry to yield 1.23 g (71.5%) of the desired product.
4,7-bis(4-{5-[1-Vinyl-allyloxycarbonyl]pentyloxy}phenyl)-2,1,3-benzothiadozole: A mixture of 2,5-bis(4-hydroxyphenyl)-2,1,3-benzothiadozole (0.3 g, 0.93×10 −3 mol), 1,4-pentadien-3-yl 5-bromopentanoate (0.61 g, 2.34×10 −3 mol) and potassium carbonate (0.38 g, 2.79×10 −3 mol) in N,N-dimethylformaldehyde (30 cm 3 ) was heated (80 C°) overnight. The cooled reaction mixture was filtered and the filtrate concentrated under reduce pressure. The crude product was purified by column chromatography [silica gel, ethyl acetate:hexane 1:5] followed by recrystallisation from ethanol to yield 0.39 g (61.8%) of the desired product.
Compounds 17 and 18 are preparable by an analogous process.
Thin Film Polymerisation and Evaluation
Thin films of Compounds 3 to 6 and Compunds 9 to 15 were prepared by spin casting from a 0.5%–2% M solution in chloroform onto quartz substrates. All sample processing was carried out in a dry nitrogen filled glove box to avoid oxygen and water contamination. The samples were subsequently baked at 50° C. for 30 minutes, heated to 90° C. and then cooled at a rate of 0.2° C. to room temperature to form a nematic glass. Polarised microscopy showed that no change was observed in the films over several months at room temperature. The films were polymerized in a nitrogen filled chamber using light from an Argon Ion laser. Most of the polymerization studies were carried out at 300 nm with a constant intensity of 100 MWcm −2 and the total fluence varied according to the exposure time. No photoinitiator was used. Temperature dependent polymerization studies were carried out in a Linkham model LTS 350 hot-stage driven by a TP 93 controller under flowing nitrogen gas. A solubility test was used to find the optimum fluence: different regions of the film were exposed to UV irradiation with different fluences and the film was subsequently washed in chloroform for 30 s. The unpolymerized and partially polymerized regions of the film were washed away and PL from the remaining regions was observed on excitation with an expanded beam from the Argon Ion laser. Optical absorbance measurements were made using a Unicam 5625 UV-VIS spectrophotometer. PL and EL were measured in a chamber filled with dry nitrogen gas using a photodiode array (Ocean Optics S2000) with a spectral range from 200 nm to 850 nm and a resolution of 2 nm. Films were deposited onto CaF 2 substrates for Fourier Transform infra-red measurements, which were carried out on a Perkin Elmer Paragon 1000 Spectrometer. Indium tin oxide (ITO) coated glass substrates, (Merck 15Ω/□) were used for EL devices. These were cleaned using an Argon plasma. 20 A PDOT (EL-grade, Bayer) layer of thickness 45 nm±10% was spin-cast onto the substrate and baked at 165° C. for 30 minutes. This formed a hole-transporting film. One or more organic films of thickness≈45 nm were subsequently deposited by spin-casting and crosslinked as discussed below. Film thicknesses were measured using a Dektak surface profiler. Aluminum was selectively evaporated onto the films at a pressure less than 1×10 −5 torr using a shadow mask to form the cathode.
Photopolymerisation Details
The optimum fluences required in order to polymerize the diene monomers (Compounds 3 to 6) efficiently with a minimum of photodegradation, were found to be 100 Jcm −2 , 20 Jcm −2 , 100 Jcm −2 and 300 Jcm −2 respectively, using the solubility test. As Scheme 6 shows, the 1,6-heptadiene monomer (e.g. Compound 4) forms a network with a repeat unit containing a single ring. Its polymerization rate is equal to that of the 1,4-pentadiene monomer (e.g. Compounds 3 and 5) but the increase of PL intensity after polymerization is less for Compound 4. This may be because of the increased flexibility of the C 7 ring in the backbone of the crosslinked material. The 1,4-pentadiene diene monomers (Compounds 3 and 5) are homologues and differ only in the length of the flexible alkoxy-spacer part of the end-groups. The PL spectrum of Compound 5 with the shorter spacer is significantly different to all other materials before exposure suggesting a different conformation. The higher fluence required to polymerize the 1,4-pentadiene monomer Compound 5 implies that the polymerization rate is dependent on the spacer length: the freedom of motion of the photopolymerizable end-group is reduced, because of the shorter aliphatic spacer in Compound 5. The diallylamine monomer Compound 6 has a significantly different structure to the dienes. It is much more photosensitive than the other diene monomers because of the activation by the electron rich nitrogen atom. Scheme 6 also shows (by way of comparison) that when a methacrylate monomer is employed the polymerization step does not involve the formation of a ring.
Photopolymerization Characteristics
The absorbance and PL spectra of 1,4-pentadiene monomer (Compound 3) were measured before and after exposure with the optimum UV fluence of 100 J cm −2 . The latter measurements were repeated after washing in chloroform for 30 s. The absorbance spectra of the unexposed and exposed films are almost identical and the total absorbance decreases by 15% after washing indicating that only a small amount of the material is removed. This confirms conclusively that a predominantly insoluble network is formed.
The UV irradiation was carried out in the nematic glass phases at room temperature at 300 nm. The excitation of the fluorene chromophore is minimal at this wavelength and the absorbance is extremely low. The experiment was repeated using a wavelength of 350 nm near the absorbance peak. Although the number of absorbed photons is far greater at 350 nm, a similar fluence is required to form an insoluble network. Furthermore excitation at 350 nm results in some photodegradation. UV photopolymerization was also carried out at 300 nm at temperatures of 50° C., 65° C. and 80° C. all in the nematic phase. It was anticipated that the polymerization rate would increase, when the photoreactive mesogens were irradiated in the more mobile nematic phase. However, the fluence required to form the crosslinked network was independent of temperature, within the resolution of our solubility test. Furthermore, the integrated PL intensity from the crosslinked network decreases with temperature indicating a temperature dependent photodegradation.
Bilayer Electroluminescent Devices
Bilayer electroluminescent devices were prepared by spin-casting the 1,4-pentadiene monomer (Compound 3) onto a hole-transporting PEDT layer. The diene functioned as the light-emitting and electron-transporting material in the stable nematic glassy state. Equivalent devices using cross-linked networks formed from Compound 3 by photopolymerisation with UV were also fabricated on the same substrate under identical conditions and the EL properties of both types of devices evaluated and compared. The fabrication of such bilayer OLEDs is facilitated by the fact that the hole-transporting PEDT layer is insoluble in the organic solvent used to deposit the electroluminescent and electron-transporting reactive mesogen (Compound 3). Half of the layer of Compound 3 was photopolymerized using optimum conditions and the other half was left unexposed so that EL devices incorporating either the nematic glass or the cross-linked polymer network could be directly compared on the same substrate under identical conditions. Aluminum cathodes were deposited onto both the cross-linked and non cross-linked regions. Polarized electroluminescent devices were prepared by the polymerization of uniformly aligned Compound 3 achieved by depositing it onto a photoalignment layer doped with a hole transporting molecule. In these devices external quantum efficiencies of 1.4% were obtained for electroluminescence at 80 cd m −2 . Three layer devices were also prepared by spin-casting an electron transporting polymer (Compound 7), which shows a broad featureless blue emission, on top of the crosslinked nematic polymer network. In the case of both the three layer and bilayer devices the luminescence originates from the cross-linked polymer network of the 1,4-pentadiene monomer (Compound 3). The increased brightness of the three-layer device may result from an improved balance of electron and hole injection and/or from a shift of the recombination region away from the absorbing cathode.
Multilayer Device
A multilayer device configuration was implemented as illustrated in FIG. 2 . A glass substrate 30 (12 mm×12 mm×1 mm) coated with a layer of indium tin oxide 32 (ITO) was cleaned via oxygen plasma etching. Scanning electron microscopy revealed an improvement in the surface smoothness by using this process which also results in a beneficial lowering of the ITO work function. The ITO was coated with two strips (˜2 mm) of polyimide 34 along opposite edges of the substrate then covered with a polyethylene dioxthiophene/polystyrene sulfonate (PEDT/PSS) EL-grade layer 36 of thickness 45±5 nm deposited by spin-coating. The layer 36 was baked at 165° C. for 30 min in order to cure the PEDT/PSS and remove any volatile contaminants. The doped polymer blend of Compounds 1 and 2 was spun from a 0.5% solution in cyclopentanone forming an alignment layer 40 of thickness ˜20 nm. This formed the hole-injecting aligning interface after exposure to linearly polarized CV from an argon ion laser tuned to 300 nm. A liquid-crystalline luminescent layer 50 of Compound 3 was then spun cast from a chloroform solution forming a film of ˜10 nm thickness. A further bake at 50° C. for 30 min was employed to drive off any residual solvent. The sample was heated to 100° C. and slowly cooled at 02° C./min to room temperature to achieve macroscopic alignment of chromophores in the nematic glass phase. Irradiation with UV light at 300 nm from an argon ion laser was used to induce crosslinking of the photoactive end-groups of the Compound 3 to form an insoluble and intractable layer. No photoinitiator was used hence minimizing continued photoreaction during the device lifetime. Aluminium electrodes 50 were vapor-deposited under a vacuum of 10° mbar or better and silver paste dots 52 applied for electrical contact. A silver paste contact 54 was also applied for contact with the indium tin oxide base electrode. This entire fabrication process was carried out under dry nitrogen of purity greater than 99.99%. Film thickness was measured using a Dektak ST surface profiler.
The samples were mounted for testing within a nitrogen-filled chamber with spring-loaded probes. The polymide strips form a protective layer preventing the spring-loaded test probes from pushing through the various layers. Optical absorbance measurements were taken using a Unicam UV-vis spectrometer with a polarizer (Ealing Polarcaot 105 UV-vis code 23-2363) in the beam. The spectrometer's polarization bias was taken into account and dichroic ratios were obtained by comparing maxima at around 370–380 nm.
Luminescence/voltage measurements were taken using a photomultiplier tube (EMI 6097B with S11 type photocathode) and Keithley 196 multimeter with computer control. Polarized EL measurements were taken using a photodiode array (Ocean Optics S2000, 200–850 nm bandwidth 2 nm resolution) and polarizer as described above. The polarization bias of the spectrometer was eliminated by use of an input fiber (fused silica 100 μm diameter) ensuring complete depolarisation of light into the instrument.
Monochrome Backlight
FIG. 3 shows a schematic representation of a polarised light monochrome backlight used to illuminate a twisted nematic liquid crystal display. The arrows indicate the polarisation direction. An inert substrate 30 (e.g. glass coated with a layer of indium tin oxide (ITO) as in FIG. 2 ) is provided with a layer 50 of a polarised light emitting polymer (e.g. comprising Compound 3 as in FIG. 2 ). The assembly further includes a clean up polariser 60 comprising a high transmission low polarisation efficiency polariser; a twisted nematic liquid crystal display 70 ; and a front polariser 80 . It will be appreciated that the light emitting polymer layer 50 acts as a light source for the liquid crystal display 70 .
Polarised Light Sequential Tri-color Backlight
FIG. 3 schematic of a polarised light sequential red, green and blue light emitting backlight used to illuminate a fast liquid crystal display (ferroelectric display). The arrows indicate the polarisation direction. An inert substrate 30 (e.g. glass coated with a layer of indium tin oxide (ITO) as in FIG. 2 ) is respectively provided with red 52, green 54 and blue 56 striped layers of a polarised light emitting polymer (e.g. comprising Compound 3 as in FIG. 2 and a suitable dye molecule as a dopant). The assembly further includes a clean up polariser 60 comprising a high transmission low polarisation efficiency polariser; a fast (ferroelectric) liquid crystal display 70 ; and a front polariser 80 . It will be appreciated that the striped light emitting polymer layer 52 , 54 , 56 acts as a light source for the fast liquid crystal display 70 . The sequential emission of the RGB stripes corresponds with the appropriate colour image on the fast liquid crystal display. Thus, a colour display is seen.
Alignment Characteristics
The PL polarization ratio (PL η /PL ⊥ ) of the aligned polymer formed from Compound 3 in its nematic glass phase can be taken as a measure of the alignment quality. Optimum alignment is obtained with the undoped alignment layer for an incident fluence of 50 mJ cm −2 . The alignment quality deteriorates when higher fluences are used. This is expected because there are competing LC-surface interactions giving parallel and perpendicular alignment respectively. When the dopant concentration is 40% or higher there is a detrimental effect on alignment. However with concentrations up to 30% the polarization ratio of emitted light is not severely effected although higher fluences are required to obtain optimum alignment. The EL intensity reaches its peak for the ˜50% mixture. A 30% mixture offers a good compromise in balancing the output luminescence intensity and polarization ratio. From these conditions and using the 30% doped layer we have observed strong optical dichroism in the absorbance (D˜6.5) and obtained PL polarization ratios of 8:1.
Electroluminescence Characteristics
Devices made with compound 3 in the nematic glassy state showed poor EL polarization ratios because the low glass transition temperature compromised the alignment stability. Much better performance was achieved when compound 3 was crosslinked.
A brightness of 60 cd m −2 (measured without polarizer) was obtained at a drive voltage of 11V. The threshold voltage, EL polarization ratio and intensity all depend on the composition of the alignment layer. A luminance of 90 cd m −2 was obtained from a 50% doped device but with a reduction in the EL polarization ratio. Conversely a polarized EL ratio of 11:1 is found from a 20% doped device but with lower brightness. A threshold voltage of 2V is found for the device with a hole-transporting layer with 100% of the dopant comprising compound 2. Clearly a photo-alignment polymer optimised for both alignment and hole-transporting properties would improve device performance. This could be achieved using a co-polymer incorporating both linear rod-like hole-transporting and photoactive side chains. | There is provided a process for forming a light emitting polymer comprising photopolymerization of a reactive mesogen having an endgroup which is susceptible to photopolymerization e.g. By a radical polymerization process. Also provided are methods for using the light emitter in displays, backlights, electronic apparatus and security viewers. |
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH &
DEVELOPMENT
The U.S. Government may have certain rights in this invention pursuant to contract number F33657-95-C-0055 awarded by the Department of the Air Force.
BACKGROUND OF THE INVENTION
This invention relates generally to gas turbine engines and more particularly to shroud assemblies utilized in the high pressure turbine section of such engines.
A gas turbine engine includes a compressor that provides pressurized air to a combustor wherein the air is mixed with fuel and ignited for generating hot combustion gases. These gases flow downstream to one or more turbines that extact energy therefrom to power the compressor and provide useful work such as powering an aircraft in flight A turbine section commonly includes a stationary turbine nozzle disposed at the outlet of the combustor for channeling combustion gases into a turbine rotor disposed downstream thereof. The turbine rotor indudes a plurality of circumferentially spaced apart fan blades extending radially outwardly from a rotor disk that rotates about the centerline axis of the engine.
The turbine section further includes a shroud assembly located immediately downstream of the turbine nozzle. The shroud assembly closely surrounds the turbine rotor and thus defines the outer boundary for the hot combustion gases flowing through the turbine. A typical shroud assembly comprises a shroud support which is fastened to the engine outer case and which in turn supports a plurality of shrouds. The shrouds are held in place, in part, by arcuate retaining members commonly referred to as C-clips. Specifically, the C-clips hold the aft end of the shrouds in place against the shroud hangers via an interference fit.
The interference fit normally provides excellent retention of the shrouds. However, there can be a tendency for the C-clips to back off in some instances because of a thermal ratcheting phenomenon. That is, although the shrouds and C-clips are segmented to accommodate for thermal expansion, there is a possibility that the thenmal loads within the shroud assembly can cause the C-clip to rock and thereby overcome the interference fit clamp loads. In some cases, there may be enough of a gap between the C-clip aft face and the adjacent nozzle outer band to allow for C-clip disengagement Such disengagement could result in severe hardware damage.
Accordingly, there is a need for a C-clip design that eliminates C-clip back-off.
SUMMARY OF THE INVENTION
The above-mentioned needs are met by the present invention which provides a C-clip having at least one anti-rocking pad disposed thereon. The anti-rocking pad makes snug contact with the portion of the shroud adjacent to the C-clip so as to limit arny rocking motion of the C-clip, thereby preventing C-clip disengagement.
Other objects and advantages of the present invention will become apparent upon reading the following detailed description and the appended claims with reference to the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding part of the specification. The invention, however, may be best understood by reference to the following description taken in conjunction with the accompanying drawing FIGS. in which:
FIG. 1 is an axial sectional view of a shroud assembly including the C-clip of the present invention.
FIG. 2 is an enlarged sectional view of the shroud assembly of FIG. 1 showing the C-clip in mote detail.
FIG. 3 is a perspective view of the C-clip of FIG. 2 .
FIG. 4 is an aft-looking-forward end view showing a first embodiment of the C-clip of the present invention.
FIG. 5 is an aft-looking-forward end view showing a second embodiment of the C-clip of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views, FIG. 1 shows a shroud assembly 10 in closely surrounding relation with turbine blades 12 carried by a rotor disk (not shown) in the high pressure turbine section of a gas turbine engine. The shroud assembly 10 includes a plurality of arcuate shrouds 14 (only one shown in FIG. 1) arranged in an annular array so as to encircle the turbine blades 12 . The shrouds 14 are held in position by a shroud support 16 which, in turn, is supported by the engine outer case (not shown) in a conventional manner.
The shroud support 16 includes an axially extending forward hook 18 and an axially extending aft hook 20 . The shroud support 16 also has an aft lip wear surface 22 formed on its aft face. The aft lip wear surface 22 provides a contact surface for a leaf seal 24 which is disposed between the shroud assembly 10 and the nozzle outer band 26 of the adjacent stator assembly. A conventional flow divider 28 is attached to the shroud support 16 via bolts 30 .
Each shroud 14 includes a base 32 having radially outwardly extending forward and aft rails 34 and 36 , respectively. A forward mounting flange 38 extends forwardly from the forward rail 34 of each shroud 14 , and an aft mounting flange 40 extends rearwardly from the aft rail 36 of each shroud 14 . The aft mounting flanges 40 of each shroud 14 are juxtaposed with the aft hook 20 of the shroud support 16 and are held in Icace by a plurality of retaining members 42 commonly referred to as C-clips.
The C-clips 42 comprise arcuate body members that are C-shaped in cross section and snugly overlap the aft mounting flanges 40 and the aft hook 20 so as to clamp the aft ends of the shrouds 14 in place against the shroud support 16 . Although they could be formed as a single continuous ring, the C-clips 42 are preferably segmented to accommodate thermal expansion. Typically, one C-clip 42 clamps an entire shroud plus one-half of each adjacent shroud. In which case, there are twice as many shrouds 14 as there are Iclips 42 .
As mentioned above, repetitive thermal expansion and contraction can sometimes cause conventional C-clips to rock with respect to their associated mounting flanges and hooks. If unchecked, such rocking could cause C-clip disengagement. To counter the rocking effect, at least one anti-rocking pad 46 is disposed on the radially inner surface (with respect to the centerline axis of the engine) of the C-clip 42 . As described in more detail below, the antirocking pad 46 contacts the shroud 14 so as to limit the C-clip's capacity to rock.
The forward end of each shroud 14 is supported from the shroud support 16 via conventional shroud hangers 48 . Each shroud hanger 48 includes a first hook 50 that engages the forward hook 18 of the shroud support 16 and a second hook 52 that engages the forward mounting flange 38 of each shroud 14 . The shroud hangers 48 are also secured to the shroud support 16 by fasteners 54 . A conventional cooling air distributor 56 is disposed between the shroud 14 and the shroud support 16 for distributing cooling air to the shrouds 14 and adjacent structure. It should be noted that the present invention is not limited to the shroud assembly shown in FIG. 1 . In other shroud assemblies, the aft end of the shroud is clamped to a shroud hanger, instead of directly to a shroud support, via a C-clip. The C-clip of the present invention is equally applicable to this type of configuration or any other type of shroud supporting structure that uses a C-clip.
Referring to FIGS. 2 and 3, a C-clip 42 is shown in greater detail. As mentioned above, each C-clip 42 comprises an arcuate body member that is C-shaped in cross section. Specifically, the C-clip 42 includes a connector portion 58 having first and second tines 60 , 62 extending therefrom, with the first tine 60 being located radially inside of the second tine 62 . The second tine 62 engages the aft hook 20 , and the first tine 60 engages the aft mounting flange 40 . To engage the aft mounting flange 40 , the first tine 60 is located in a gap 64 formed between the aft nmounting flange 40 and the rearmost portion of the shroud base 32 .
The anti-rocking pad 46 is disposed on the radially inner surface of the first fine 60 so as to be located between the C-clip 42 and the shroud base 32 . The thickness of the anti-rocking pad 46 is such that it will contact the shroud base 32 . That is, the combined thickness of the first tine 60 and the anti-rocking pad 46 is substantially equal to the width of the gap 64 . Typically, the thickness of the antirocking pad 46 will be in the range of about 0.01-0.02 inches.
The firm contact between the anti-rocking pad 46 and the base 32 of the shroud 14 limits the capacity the C-clip 42 to rock with respect to the aft hook 20 and the aft mounting flange 40 . Accordingly, the anti-rocking pad 46 reduces the possibility of C-clip disengagement. To best eliminate C-clip rocking action, the anti-rocking pad 46 is preferably located near the aft end of the C-clip 42 . The anti-rocking pad 46 can be made of any suitable material and is preferably made of the same material as the C-clip 42 . The anti-rocking pad 46 can be a separate element attached to the C-clip 42 by conventional means such as welding or bonding, or it can be integrally formed with the C-clip 42 .
Turning to FIG. 4, it can be seen, in one preferred ernbodiment, that the anti-rocking pad 46 is drcumferentially centered on the radially inner surface of the first Une 60 . That is, the anti-rocking pad 46 is located about midway between the opposing ends of the C-clip 42 . FIG. 5 shows anothe- preferred embodiment in which three anti-rocking pads 46 are disposed on the radially inner surface of the first tine 60 . One anti-rocking pad 46 is located midway between the opposing ends of the C-clip 42 , a second anti-rocking pad 46 is located near a first end of the C-clip 42 and a third anti-rocking pad 46 is located near the other end of the C-clip 42 . The multiple anti-rocking pads of FIG. 5 are generally not as wide as the single anti-rocking pad of FIG. 4 .
The foregoing has described a C-clip having an anti-rocking pad that eliminates C-clip back-off. In addition to eliminating the potential of C-clip disengagement, the C-clip of the present invention provides further advantages in that it requires only limited modification to existing C-clip configurations and requires essentially no modification to other shroud assembly structure. While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention as defined in the appended claims. | Disengagement of C-clips in turbine shroud assemblies is prevented by providing each C-clip with at least one anti-rocking pad. The anti-rocking pad is disposed on a radially inner surface of the C-clip so as to make snug contact with a portion of the shroud adjacent to the C-clip. The snug contact limits rocking motion of the C-clip, thereby preventing C-clip disengagernent. |
FIELD OF THE INVENTION
The present invention relates to a process for the preparation of an acidic lipase. More particularly, the present invention relates to the production of thermostable and acid stable lipase using Aspergillus niger.
BACKGROUND OF THE INVENTION
Research on microbial lipases has increased in recent years because of their practical application in industry in the hydrolysis of fats, production of fatty acids and food additives, synthesis of esters and peptides, resolution of racemic mixtures or as additives for detergents. [Bjorkling F., Godtfredsen S. E., and Kirk O., (1991), Trends Biotechnol. 9, 360-363]. These enzymes are widely distributed in filamentous fungi [Sugihara A., Shimada Y., and Tominaga Y., (1990), J. Biochem. 107, 426-430; Torossian K. and Bell A. W. (1991) Biotechnol. Appl. Biochem. 13, 205-211; Yadav R. P., Saxena R. K., Gupta R., and Davidson W. S., (1998) Biotechnol. Appl. Biochem. 28, 243-249], yeasts [Kalkote U. R., Joshi R. A., Ravindranathan T., Bastawade K. B., Patil S. G., and Gokhale D. V., (1992) Biotechnol. Lett. 14, 785-788; Valero F., Ayats F., Lopez-Santin J., and Poch M. (1998) Biotechnol. Lett. 10, 741-744; Dalmau E., Montesions J. L., Lotti M. and Casas C., (2000), Enzyme Microb. Technol. 26, 657-663] and bacteria [Jaeger K. E., Ransae S., Dijkstra B. W., Colson C., van Heuvel M. S. and Misset O. (1994) FEMS Microbiol. Rev. 15, 29-63; Jaeger K. E., Dijkstra B. W. and Reetz M. T., (1999) Ann. Rev. Microbiol. 53, 315-351].
Filamentous fungi are preferred sources of lipase since they secrete the enzymes extracellularly. The most productive strains known till date belong to the genera Rhizopus, Mucor, Geotrichum, Penicillium and Aspergillus [Bjorkling F., Godtfredsen S. E., and Kirk O., (1991), Trends Biotechnol. 9, 360-363]. An acid resistant lipase preparation active between pH 4.5-5.5 was reported from Aspergillus niger [Torossian K. and Bell A. W. (1991) Biotechnol. Appl. Biochem. 13, 205-211]. Lipases active at highly acidic pH's have not been reported so far from microbial sources. Such acidic lipases have potential applications in the food industry. It is therefore desirable to obtain such acidic lipases which are active at highly acidic pH from microbial sources.
OBJECTS OF THE INVENTION
The main object of the invention is to provide a process for the preparation of acidic lipase which is active even at highly acidic pH from microbial sources.
It is another object of the invention to provide a process for the preparation of acidic lipase which is active even at highly acidic pH using Aspergillis niger.
SUMMARY OF THE INVENTION
Accordingly the present invention provides a process for the preparation of acidic lipase, said process comprising growing Aspergillus niger sp. in a conventional fermentation medium containing carbon and nitrogen sources along with conventional nutrients for a period in the range of 72-96 hours at a temperature in the range of 25° C. to 35° C. under agitation, separating the fungal biomass and recovering the culture filtrate/broth and separating the lipase enzyme.
In one embodiment of the invention, the fungal strain used is isolated from decaying wood and is deposited at the National Collection of Industrial Microorganisms (NCIM), Biochemical Sciences Division, National Chemical Laboratory, Pune 411 008, India and designated as Aspergillus niger NCIM 1207.
In another embodiment of the invention, the dry mycelium of Aspergillus niger is prepared after harvesting the growth of the fungal strain, washing the mycelium with distilled water followed by washing with chilled acetone, drying the acetone treated mycelium under vacuum for 6-10 hours to remove acetone and water.
In a further embodiment of the invention, a CELITE (diatomaceous earth) bound (extracellular) enzyme is prepared by adding CELITE (diatomaceous earth) 545 (1 gm) to culture filtrate (20 ml) with mixing, ice cold acetone (25 ml) added to the suspension over a period of 5 minutes while stirring, the resultant suspension stirred for another 30 minutes using a magnetic stirrer at 0° C., filtered and dried.
DETAILED DESCRIPTION OF THE INVENTION
The dry mycelium of Aspergillus niger is prepared after harvesting the growth of the fungal strain, washing the mycelium with distilled water followed by washing with chilled acetone, drying the acetone treated mycelium under vacuum for 6-10 hours to remove acetone and water. The vacuum dried mycelial preparation was used for the estimation of cell bound (intracellular) activity on the basis of formation of esters.
CELITE (diatomaceous earth) bound (extracellular) enzyme is prepared by adding CELITE (diatomaceous earth) 545 (1 gm) to culture filtrate (20 ml) with mixing. Ice cold acetone (25 ml) was then added to the suspension over a period of 5 minutes while stirring, the resultant suspension stirred for another 30 minutes as source of extracellular enzyme. The extracellular enzyme activity was measured on the basis of formation of butyl esters.
Aspergillus niger NCIM 1207 was used. Fermentation was done under submerged conditions. Lipase enzyme was produced by growing Aspergillus niger strain on a conventional growth medium such as MGYP (malt extract 0.3%; glucose 5.0%; yeast extract 0.3%; peptone 0.5% and Agar 2.0%) for 8-10 days at 25-30° C. The fermentation medium used was selected from MGYP liquid medium and basal oil based (BOB) medium (NaNO 3 0.05%; MgSO 4 .7H 2 O 0.05%; KCl 0.05%; KH 2 PO 4 0.2%; yeast extract 0.1%; peptone 0.5%; and olive oil 2.0%). All the media were sterilised at 15 lbs for 20 minutes. The pH of the media was adjusted to 5.5 prior to sterilisation. Resultant fermentation medium was inoculated with spores (10 8 -10 9 ) from fully grown agar slope and was incubated at 25-30° C. for 72-96 hours with shaking at 150-180 rpm. Biomass was separated by known methods such as filtration to recover the broth and lipase activity was estimated by pNPP assay or on the basis of formation of butyl esters (indicative of lipase activity).
The process of the invention is described further with reference to the following examples, which are merely illustrative and are not to be construed as limiting the scope of the invention.
EXAMPLE 1
Culture was grown in 500 ml conical flasks with 100 ml of fermentation medium. The medium was inoculated with spores (10 8 10 9 ) from 8 days old MGYP slope and incubated at 30° C. with shaking. The mycelium was harvested by filtration and the culture filtrate is used as the source of extracellular enzyme. Lipase activity is based on the formation of butyl esters by transesterification of butter oil with butanol. The transesterification reaction was carried out in a 25 ml stoppered conical flask, which was shaken at 100 strokes per minute in a controlled temperature water bath, normally at 37° C. for 24 hours. The reaction mixture contained 50 mg vacuum dry mycelium or 500 mg CELITE (diatomaceous earth) absorbed enzyme preparation, 250 mg butter oil and 5.5 gm water saturated butanol. Fifty microlitre of water/buffer was added to the reaction mixture when the vacuum dried mycelial preparation was used. Analysis of esters was carried out by GLC using capillary column (Phillips, 0.25 um film of silicon OV1, 3.8 m×90.22 mm; injector and FI detector at 300° C.). For samples that contain incompletely solvolyzed or unchanged triglycerides, the temperature was set at 40° C. for 3 minutes then rising at 3° C. per minute up to 320° C. to elute unchanged triglycerides. Esters were identified by interpolation from standards. Analysis was carried out on 1u1 samples using added undecane (0.15 mg ml −1 ) as an internal standard which was prepared in n-hexane. For fast and routine measurements of lipase activity, the spectrophotometric method of p-nitrophenylpalmitate (pNPP) was used. The method was slightly modified as follows: solution A: 40 mg of pNPP dissolved in 12 ml of propan—2 ol; solution B: 0.1 g of gum Arabic and 0.4 g of Triton X—100 dissolved in 90 ml of water. The substrate solution was prepared by adding 1 ml of solution A to 19 ml of solution B dropwise and under intense stirring to get an emulsion which remained stable for at least 2 hours. For lipase activity measurement, the assay mixture consisting of 0.9 ml substrate solution, 0.1 ml buffer (0.5 M) and 0.1 ml of suitable diluted enzyme, was incubated for 20 minutes at suitable temperature (30-60° C.). The p-nitrophenol liberated was measured at 410 nm.
TABLE 1
Ester formed (mg ml −1 )
Medium
Biomass (mg dry weight)*
Intracellular
Extracellular
MGYP
450 ± 23
Not detected
Not detected
BOB
1350 ± 95
0.58
2.25
*the biomass was obtained from 100 ml of fermentation medium.
All the values are the averages of three independent experiments and the standard deviation ranges between 5-8%.
Table 1 shows the growth and enzyme production in MGYP and BOB media. Data on the formation of one of the esters (butyl oleate) are presented since it is not practical to show all the different esters formed. Aspergillus niger NCIM 1207 produced neither intracellular nor extracellular activity in MGYP medium. Lipase production appeared to be inducible since both intra- and extracellular lipase activity was detected in only oil based medium, with maximum activity detected extracellularly.
EXAMPLE 2
The effect of temperature on enzyme activity was studied by incubating the assay mixture at temperatures ranging between 30° C. to 70° C. for 20 minutes. The assay mixture consisted of 0.9 ml of the substrate (pNPP), 0.1 ml of citrate buffer (pH 2.5, 0.5 M) and 0.1 ml of suitable diluted enzyme. The p-nitrophenol released was measured at 410 nm. It was observed that the enzyme was active over a broad temperature range between 35° C. to 60° C. with maximum activity at 45° C.
EXAMPLE 3
The effect of different pH's on lipase activity was studied using the buffer systems (0.05 M), KCl—HCl buffer (pH 1.5 and 2.0), citrate phosphate (pH 2.5-6.0). Assay mixture consisting of 0.9 ml substrate solution (pNPP), 0.1 ml buffer (0.5 M) and 0.1 ml of suitable diluted enzyme was incubated at 45° C. and p-nitrophenol released was measured at 410 nm. It was observed that enzyme was active at pH 2.5-3.0.
EXAMPLE 4
The temperature stability studies for lipase enzyme were carried out by incubating the extracellular enzyme (culture filtrate) at different temperatures between 30° C. to 70° C. and estimating the residual activity after different time intervals (1 hour to 4 hours). The residual enzyme activity was determined using pNPP substrate. Assay mixture consisting of 0.9 ml substrate solution (pNPP), 0.1 ml buffer (pH 2.5, 0.5 M) and 0.1 ml of suitably diluted enzyme was incubated at 45° C. and p-nitrophenol released was measured at 410 nm. The enzyme was found to be stable at temperatures between 30° C. and 60° C. for 4 hours.
EXAMPLE 5
The stability of the enzyme at different pH's (1.5-9.0) was studied by incubating the extracellular enzyme (culture filtrate) at 40° C. and at as different pH (KCl—HCl buffer, pH 1.5 and 2.0; Citrate phosphate, pH 2.5-7.0; boric acid—borax buffer, pH 8.0-9.0) and estimating the residual activity at different time intervals (1 hour to 4 hours) by pNPP assay. Assay mixture consisting of 0.9 ml substrate solution (pNPP), 0.1 ml buffer (pH 2.5, 0.5 M) and 0.1 ml of suitably diluted enzyme was incubated at 45° C. and p-nitrophenol released was measured at 410 nm. The enzyme was stable up to 4 hours between wide pH range (3.0-9.0) with slight decline in enzyme activity when incubated at pH 2.0. | The present invention provides a process for the preparation of acidic lipase from microbial sources with activity at highly acidic pH, the process comprising growing Aspergillus niger sp. In a fermentation medium containing carbon and nitrogen sources along with nutrients, separating the fungal biomass and recovering the culture filtrate/broth and separating the lipase enzyme. |
BACKGROUND OF THE INVENTION
[0001] This invention relates to the field of catalytic combustion and/or heat exchange. The present invention provides a cartridge that can be used as a heat exchanger or a catalytic or non-catalytic reactor, and which can be stacked with similar cartridges in a long tube or pipe. The invention also includes a method of moving a cartridge into or out of a pipe, and a tool for accomplishing such transfer.
[0002] The cartridge of the present invention achieves the same objectives as that of the catalyst support described in copending U.S. Pat. application Ser. No. 10/896,302, filed Jul. 21, 2004, the disclosure of which is incorporated by reference herein.
[0003] One of the objectives of the above-cited application is to avoid the problems associated with the use of ceramic materials in the manufacture and operation of catalytic reactors. Packed bed ceramic catalysts have the disadvantage that they have low thermal conductivity, making it difficult to transfer heat from the periphery of the reactor to the inside. Also, the thermal mismatch between the metal and ceramic portions of prior art reactors eventually leads to pulverization of the ceramic material, thus limiting the useful life of the reactor. Like the device described in the above-cited application, the present invention also comprises an all-metal structure which inherently avoids these problems.
[0004] Another object of a catalytic reactor or heat exchanger is to provide adequate mixing of gas streams so as to promote heat transfer between the wall of the reactor and the gases flowing therein. Thus, in the application cited above, skewed or angled corrugations define curved paths which impart a swirl to gases as they exit the reactor. The present invention also provides a structure that promotes mixing and/or swirling of gases.
[0005] The cartridge of the present invention can be used, for example, in the field of catalytic fuel reforming, to make hydrogen, which is then used in generating electricity through a fuel cell, or in other industrial processes such as oil and gas refining, ammonia and fertilizer production, hydrogenation of oils and chemicals, and iron ore reduction. The cartridge could be used as a catalytic or non-catalytic combustor. The cartridge could also be used as.a simple heat exchanger.
SUMMARY OF THE INVENTION
[0006] In one preferred embodiment, the present invention comprises a cartridge having a plurality of spaced-apart monoliths, each monolith defining channels for gas flow, each monolith imparting a swirl to gases flowing through the channels. Adjacent monoliths impart swirls that have different directions. In particular, the direction of swirl of the gas is reversed from one monolith to the next. This reversal causes turbulence in the mixing areas between monoliths, and enhances heat transfer between the exterior and the interior of the monoliths.
[0007] The monoliths are preferably formed of pairs of flat and corrugated metal strips, the strips being wound around a mandrel, such as a tube or rod, to define a spiral structure. Each corrugated strip has corrugations that are oblique to the longitudinal axis of the strip. The oblique orientation of the corrugations is what imparts the swirl to the gases. The spaces between monoliths comprise mixing areas for gas. Retainers may be inserted in these spaces, to help maintain the spacing and to prevent telescoping of the layers of the monoliths, due to pressure of the gas stream. The strips may be conventional metal foil strips, or they may be made of a fine-pitch screen, to allow additional mixing and heat transfer by radiation.
[0008] The invention also includes a method of making a catalytic combustor cartridge. In this method, one affixes pairs of flat and corrugated metal strips, at spaced-apart locations along a mandrel, and winds the pairs of strips around the mandrel, such as by turning the mandrel on its longitudinal axis, to form a plurality of spaced-apart, spirally-wound monoliths. The corrugated strips are formed with corrugations that are oblique to the longitudinal axis of the strip. If the cartridge is to be used as a catalytic combustor, the strips can be coated with a suitable catalyst before they are wound to form the monoliths. The monoliths can then be placed in an enclosure, such as a screen. Retainers may also be placed between adjacent monoliths.
[0009] Another aspect of the invention is a method of inserting a reactor cartridge into a pipe, and of removing said cartridge. An insertion tool is attached to an end of the cartridge, and the cartridge is extracted from, or inserted into, a pipe, which may be, in general, many times longer than the cartridge. The insertion tool is then disengaged from the cartridge. The insertion tool preferably includes a centering device, which centers the tool within the pipe, and at least one hook which engages a lifting pin, or other structure, on the cartridge.
[0010] The invention also includes the insertion and removal tool mentioned above. This tool includes a centering device, a connector, attached to the centering device and capable of engaging a reactor cartridge, and a shaft connected to the centering device. The centering device may comprise a brush, or a cage having rollers, or some other generally cylindrical structure that fits reasonably snugly within the pipe holding the cartridge. The connector preferably includes one or more hooks, adapted to engage a lifting pin, or its equivalent, affixed to the cartridge.
[0011] The present invention therefore has the primary object of providing a reactor cartridge that can be used in catalytic or non-catalytic combustion, or for catalytic reforming, or for other endothermic or exothermic catalytic reactions, or for simple heat exchange.
[0012] The invention has the further object of providing an all-metal reactor cartridge, having a plurality of monoliths, wherein the cartridge can be stacked, with other similar cartridges, in a long pipe.
[0013] The invention has the further object of providing a reactor cartridge which promotes rapid heat transfer throughout the cartridge, and which avoids the problems associated with the use of a packed ceramic bed.
[0014] The invention has the further object of providing a method of making a reactor cartridge.
[0015] The invention has the further object of providing a method of inserting a reactor cartridge into a pipe, so as to create a stack of such cartridges.
[0016] The invention has the further object of providing a method of removing a reactor cartridge from a stack in a pipe.
[0017] The invention has the further object of providing a tool for inserting a reactor cartridge into a pipe, or for removing a cartridge from the pipe.
[0018] The reader skilled in the art will recognize other objects of the invention, from a reading of the following brief description of the drawings, the detailed description of the invention, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 provides a perspective view of a portion of a cartridge made according to the present invention, showing the fabrication of the cartridge by winding flat and corrugated strips around a tube or mandrel.
[0020] FIG. 2 provides a fragmentary perspective view, showing an insertion and removal tool for use with the cartridge of the present invention.
[0021] FIG. 3 provides a fragmentary perspective view of the tool of FIG. 2 , showing the tool being used to insert or remove a cartridge of the present invention, from a pipe.
[0022] FIG. 4 provides a cross-sectional view of the insertion and removal tool, showing the tool in engagement with the end of a cartridge made according to the present invention.
[0023] FIG. 5 provides a fragmentary perspective view showing an insertion and removal tool, made according to an alternative embodiment of the present invention, the tool being in proximity with the cartridge to be inserted or removed.
[0024] FIG. 6 provides a fragmentary perspective view of the tool of FIG. 5 , showing the tool in engagement with the cartridge, and showing the tool being used to lift the cartridge.
[0025] FIG. 7 provides a perspective view of a cartridge made according to the present invention, the cartridge being enclosed within a screen material.
DETAILED DESCRIPTION OF THE INVENTION
[0026] FIG. 1 illustrates the basic structure, and method of manufacture, of the reactor cartridge of the present invention. The cartridge is made from a plurality of corrugated strips 1 , 2 , 3 and a plurality of flat strips 4 , 5 , 6 . The corrugated strips have skew corrugations, i.e. their corrugations are oblique relative to the longitudinal axis of the strip. The strips, which are preferably made of metal foil, are welded to, and wound around, tube 7 , so as to produce three monoliths, designated by reference numerals 8 , 9 , and 10 . The monoliths are also called “honeycombs”, because they present a multiplicity of channels to gases flowing generally axially therethrough. Each of the above channels is defined by a portion of a flat strip and a portion of an adjacent corrugated strip.
[0027] Before assembly, the corrugated strips are oriented such that the corrugations of adjacent strips are non-parallel. This orientation is achieved simply by reversing the orientation of every other corrugated strip, before the strips are wound into monoliths. This reversal is visible in FIG. 1 , which shows that the corrugations of strips 1 and 3 are parallel to each other, but non-parallel to the corrugations of strip 2 .
[0028] As a consequence of the latter arrangement, adjacent monoliths in the finished structure define differently-oriented channels for gas flow. More particularly, when the strips are wound, the skew corrugations define curved or spiral channels, and the direction of the curve or spiral in a given monolith is different from that of either of the adjacent monoliths.
[0029] When the winding is complete, the resulting structure comprises a cartridge having a plurality of monoliths. Only three monoliths are shown in FIG. 1 , for simplicity of illustration, but other numbers of monoliths could be provided in each cartridge, by attaching more or fewer pairs of flat and corrugated strips to the tube 7 .
[0030] The wound structure is preferably enclosed within screen material 70 , as shown in FIG. 7 . The screen material protects the monoliths and helps to hold them together. The screen may have a mesh that is relatively fine, comparable to that used in making a conventional window screen, or it may be relatively coarse, similar to what is used in making a rabbit cage or a chicken coop, i.e. having a mesh size of the order of 0.25 inches. A more coarse mesh has the advantage of allowing better heat transfer, and is therefore preferred, but the invention is intended to include both coarse and fine mesh sizes.
[0031] The material comprising the corrugated and/or flat strips may itself be made of a screen. In this case, the mesh size must be relatively small, such as of the order of about 0.05 inches or smaller, so that the material will have enough surface area to support a catalyst coating.
[0032] FIG. 1 indicates that flat strip 6 could be made of a screen material, as shown by fragmentary screened portion 17 . Similarly, corrugated strip 1 could be made of a screen material, as shown by fragmentary screened portion 18 . Instead of being made of an actual screen, the strips could comprise foil that is riddled with holes. The term “screen” is therefore intended to include the case in which at least one of the strips is formed with a multiplicity of holes.
[0033] In summary, the flat and corrugated strips could both be made of solid material, or they could both be made of a screen, or the flat strips could be solid and the corrugated strips could be screened, or vice versa. FIG. 1 is intended to include all possible combinations, wherein any or all of the flat and/or corrugated strips may be of solid or screen material. All such combinations are included within the scope of the invention.
[0034] The advantage of the use of a screen, for the flat and/or corrugated strips, is that the screen promotes cross-channel flow and heat transfer, and also promotes heat transfer by radiation.
[0035] The monoliths 8 , 9 , and 10 are separated by retainers 11 , 12 , and 13 . In a preferred embodiment, the retainers have the form of the “spiders” shown in FIG. 1 . The spiders are made of a flat strip of metal, as shown. Spiders 12 and 13 , which sit between monoliths, have a width that is twice the width of spider 11 , which is located at the end of the cartridge. The reason for the latter feature is that, when cartridges are stacked end-to-end in a cylindrical pipe, the widths of the spiders at the ends of adjacent cartridges together equal the widths of the internal spiders, thereby preserving a uniform spacing between all adjacent monoliths in the stack.
[0036] In addition to helping to preserve the spacing between monoliths, the retainers also prevent the layers from telescoping into one another, due to the pressure of gas flowing through the cartridge. Other means for preventing telescoping, which are known in the art, can be used instead of spiders.
[0037] Each spider is defined by a plurality of petals, such as those designated by reference numerals 14 , 15 , and 16 . The petals of adjacent spiders are intentionally positioned out of phase with each other, to produce even more turbulence in the mixing areas, so as to promote better heat transfer throughout the body of the cartridge.
[0038] The tube 7 serves as a mandrel upon which the flat and corrugated strips can be wound into a spiral structure. It also helps to anchor the monoliths in a spaced-apart condition, because the pairs of strips are welded to the tube. The monoliths are therefore held at spaced-apart locations both by the welding of the strips to the tube, and by the retainers.
[0039] Instead of a tube, one could use a solid rod. A tube is preferred because it more readily accommodates an insertion and removal tool, described below. If a tube is used, it should be blocked off, preferably by providing a partition or plug at or near the center of the tube, to prevent gas from traveling through the tube. That is, the tube is intended as a structural member and not as a gas conduit.
[0040] The cartridge of the present invention thus includes a plurality of monoliths arranged in series. The spaces between the monoliths, partially occupied by the retainers, comprise regions in which gases, exiting the various channels defined by the monoliths, can mix. The skewed corrugations define curved channels in the monolith, imparting a swirl to the gases exiting the monolith. Also, because the direction of the skew is reversed from one monolith to the next, the swirl direction is also reversed with each successive monolith. This reversing effect creates turbulence in the mixing space, promoting heat transfer between the various gas streams, and also between the outer wall of the pipe containing the cartridge and the gas streams.
[0041] In one embodiment, the monoliths have an axial length of about 2 inches, and a diameter of about 4-6 inches, with a mixing space in the range of 0.25-0.50 inches. More generally, and depending on the flow conditions, the length may be in the range of about 2-6 inches, the diameter may be in the range of about 3-7 inches, and the spacing may be in the range of about 0.12-1.0 inches. The monoliths are formed by winding the flat and corrugated strips around a tube or rod that has a diameter of about 0.75-2.0 inches. A plurality of such monoliths are conveniently arranged in a cartridge that is about 3-6 feet long. The numerical values given herein are only by way of example, and are not intended to limit the invention to any particular size or dimension.
[0042] In a more specific example, the tube could be 40 inches long, and the strips could be 2 inches wide. If the spacing between adjacent strips (monoliths) is 0.5 inches, one can form 16 monoliths along the tube or rod. That is, there would be 16 monoliths in the cartridge, with 8 imparting a clockwise swirl and 8 imparting a counterclockwise swirl.
[0043] In the reactor pipe, the cartridges are stacked one upon the other, to fill the height of the pipe, which may be about 30-40 feet. The cartridges may be anchored to a structural member, such as a rod, in the center of the pipe.
[0044] The above dimensions are given only as examples, and are not intended to limit the invention. The components of the cartridge of the present invention can be scaled up or down, with an infinite variety of dimensions, to suit the needs of a particular application. The present invention is intended to include all such variations.
[0045] Because the length of a cartridge of the present invention is, in general, much less than the length of the reactor pipe, it is necessary to provide a tool to facilitate insertion and removal of the cartridge. Each cartridge preferably includes a grasping feature in the center, for engagement with a mating feature in an insertion and removal tool. The grasping feature may be a thread, a T-slot, or some other structure. The grasping feature may be formed in the tube, or it may be defined by the retainer or spider. The insertion tool permits the cartridge to be lowered into the pipe, and to be removed from the pipe when necessary. Specific embodiments of the insertion tool are described later in this specification.
[0046] In summary, the preferred method of assembly of the catalytic reactor cartridge of the present invention is as follows. One starts with a rod or blocked tube, such as tube 7 . Next, one prepares a plurality of flat and corrugated strips, the corrugations being skewed. As noted above, some or all of these strips may comprise a screen material or a solid material. If the cartridge is to be used to conduct catalytic reactions (and not to be used, for example, as a simple heat exchanger), a catalyst coating is then applied to the strips. The coated corrugated and flat strips are tack welded to the tube, spaced apart so as to preserve the desired spacing between monoliths. The tube is then turned about its longitudinal axis, causing the strips to become wound onto the tube, forming monoliths. The strips are configured such that when the monoliths are completed, the outer layer is corrugated. A retainer, such as a spider, may be inserted between adjacent monoliths.
[0047] The resulting cartridge, which so far comprises a center rod or tube with multiple monoliths, may be wrapped with a screen material, as shown in FIG. 7 , the screen having a coarse or fine mesh. The screen used to wrap the monoliths is different from the screen material which may have been used to make some or all of the flat and corrugated strips. Optionally, the screen used to enclose the cartridge may itself have a catalytic coating. This external screen material secures the monoliths, and prevents them from unwinding, and also reduces the risk of damage to the monoliths during cartridge insertion or removal. The screen also allows gas from inside the cartridge to contact the walls of the reactor pipe. The cartridge may then be finished by adding retainers, such as the illustrated spiders, or similar protective features.
[0048] The present invention also includes an insertion and removal tool, for inserting or removing the cartridge from a long pipe. The problem to be addressed is how to extract a cartridge, made as described above, from a long pipe, which may be 40 feet in length. The cartridges are stacked end- to-end in the pipe. Because the pipe may have a very small diameter (of the order of 4-6 inches) relative to its length, the line-of-sight visibility into the pipe is very limited. In many or most cases, it may be necessary to insert or remove cartridges from the pipe without any visual feedback. The insertion tool must also be able to work in any orientation.
[0049] The connection made between the insertion and removal tool, and the cartridge, must be such that the two cannot become separated during the extraction process. Significant pulling and twisting forces may need to be applied to break the cartridge free from the wall of the pipe.
[0050] Therefore, the insertion and removal tool, used in the present invention, comprises three components:
[0051] 1) a centering device for maintaining alignment with the center tube of the stackable reactor;
[0052] 2) a connector that engages the tool with the stackable reactor cartridge; and
[0053] 3) a shaft used to insert and retrieve the tool.
[0054] The preferred constructions of the connectors of the present invention comprise a double fishhook structure and a triple fishhook structure. FIGS. 2-4 illustrate the double fishhook structure, and FIGS. 5-6 show the triple fishhook structure.
[0055] Consider first the embodiment of FIGS. 2-5 . The centering device shown in this embodiment is a brush 21 . The brush may be a standard chimney flue brush, which has been modified to accept the connector structures described below. The diameter of the brush is chosen so that it easily but snugly fits within the pipe containing the reactor cartridge. The brush has a longitudinal axis which substantially coincides with the longitudinal axis of the pipe. Thus, when inserted into pipe 23 (see FIGS. 3 and 4 ), the brush maintains the alignment of the shaft 25 with the longitudinal axis of the pipe. One advantage of the use of a brush is that it will clean the walls of the pipe as it is inserted, thus easing the extraction of the cartridges.
[0056] The centering device can assume other forms. For example, one could use a cylindrical cage (not shown) having two spoked “wheels” at each end. The length of the cage should be at least as great as its circumference. The total diameter of the cage and the rollers must be slightly less than the diameter of the pipe into which the cartridges are inserted. The cage would be connected between the shaft and the connector. The advantage of the cage is that it can be moved in either direction, within the pipe, without resistance. The bristles of the brush 21 , on the other hand, tend to resist a change of direction.
[0057] As noted above, FIGS. 2-4 illustrate the embodiment wherein the connector comprises a double fishhook. In particular, these figures show J-shaped fishhooks 27 . The fishhooks are attached to annulus 29 . The annulus preferably has threads in its center for easy connection to the centering device. The fishhooks 27 may be formed from pins that are formed into a J-shape, the pins being attached to opposite sides of the annulus, as shown.
[0058] The double fishhooks 27 engage a lifting pin 31 , most clearly visible in FIG. 4 . The lifting pin is preferably attached across the diameter of the tube 33 which supports the monoliths defining the cartridge. In this embodiment, it is assumed that a hollow tube is used. If the tube were replaced by a solid rod, the lifting pin could not be used. Instead, the fishhooks could be designed to grasp some other element, such as the retainer or spider.
[0059] Engagement of the insertion and removal tool is accomplished as follows. The tool is inserted into the pipe, and pushed towards the closest reactor cartridge. When the tool encounters the nearest cartridge, it is given a clockwise twist. If the fishhooks are resting against the lifting pin, rotation of the tool will cause the fishhooks to slip below the lifting pin. Also, rotation causes the fishhooks to slip past the pin so that the annulus can seat firmly against the end of the monolith. After the tool is so twisted, the tool is pulled upward. This motion engages the two fishhooks and the lifting pin. The fishhooks create a positive engagement in either direction of rotation, such that the reactor cartridge can be extracted. Disengagement of the tool from the cartridge can be accomplished by reversing the order of the above steps.
[0060] FIGS. 5 and 6 show the embodiment wherein the connector comprises a triple fishhook. This connector comprises three individual fishhooks 41 , each having the shape of a “J”. The hooks are bent outward from the center such that a washer 43 slipped over the combined shanks will compress the hooks. A thick washer 45 is welded into the center support tube 47 of the cartridge. When the assembly comprising the washer 43 and fishhooks 41 is pushed into the reactor cartridge, the washer 43 seats against tube 47 . As the fishhooks are pushed further towards the cartridge, the fishhooks are allowed to spring open, thereby allowing the hooks to engage the thick washer. When the extraction tool is pulled away from the cartridge, as illustrated in FIG. 6 , the cartridge is pulled away with the tool, due to the engagement of the hooks with the thick washer. The hooks can be disengaged from the thick washer by pushing washer 43 towards the hooks, thereby compressing the hooks and releasing them from engagement with the thick washer.
[0061] The shaft used to make the insertion and removal tool can be a standard chimney-brush shaft. This shaft is made in sections, threaded at each end, so that it can be inserted and extended as needed. The sections can be removed as the shaft is pulled out of the pipe, to make handling easier. The invention is not limited to the above-described construction of the shaft; other arrangements can be used, within the scope of the invention.
[0062] Although the invention has been described mainly in the context of catalytic combustion or other catalytic reactions (such as steam reforming), it should be understood that the disclosed cartridge is not limited to use in catalytic reactions. The cartridge of the present invention can be used to promote conventional combustion, or it can be used as a simple heat exchanger. Likewise, the insertion and removal tool is not limited to use in the field of catalytic or conventional combustion. The term “reactor” is used in this specification to refer to all of the above-described possibilities.
[0063] The invention can be modified in various ways. As noted above, the dimensions of the strips can be varied, and the number of monoliths in each cartridge can be changed. The angle of the skew of the corrugations can be varied. The retainers are not limited to the spiders shown, but could be replaced by equivalent devices, or in some cases, omitted entirely. These and other modifications, which will be apparent to those skilled in the art, should be considered within the spirit and scope of the following claims. | A reactor cartridge includes a plurality of spaced-apart monoliths, formed along a tube or other mandrel. Each monolith is formed of a pair of flat and corrugated metal strips, spirally wound around the tube. These strips could be made of solid or screen material. The corrugations are skewed, such that the monolith imparts a swirl to gases flowing through it. The corrugations of the strips in adjacent monoliths are oriented differently, so that successive monoliths impart different swirls to the gases, so as to promote mixing of gases and better heat transfer from the exterior to the interior of the cartridge. An insertion and removal tool simplifies the procedure for stacking such cartridges in a long pipe, or for removing cartridges from the pipe. The all-metal construction facilitates heat transfer through the entire reactor, and avoids the problems associated with packed ceramic beds. |
This application claims priority from co-pending U.S. Provisional Application, U.S. Ser. No. 60/206,083, filed May 19, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the treatment of allergic diseases. More particularly, the present invention relates to therapeutic and prophylactic use of certain disulfide derivatives for treating or preventing allergic diseases.
2. Description of the Related Art
Antihistamines and mast cell stabilizers are two types of drugs currently used topically to treat allergic diseases. Antihistamine drugs are used to interrupt the allergic effects that histamine causes after it has been released from a mast cell. Many topical antihistamine drugs are marketed. For example, emedastine difumarate and levocabastine hydrochloride are available for ocular allergies (see Ophthalmic Drug Facts 1999, Facts and Comparisons, St. Louis, Mo., pp. 59-80).
Mast cell stabilizers prevent mast cells from “degranulating” or releasing histamine and other components or “mediators” during an allergic reaction. Examples of ophthalmic drugs marketed as mast cell stabilizers include olopatadine (see U.S. Pat. No. 5,641,805) and cromolyn sodium.
U.S. Pat. No. 4,705,805 discloses certain disulfide derivatives that are useful as anti-thrombotic agents. The disulfide derivatives suppress blood platelet aggregation. The '705 patent does not disclose the use of disulfide derivatives in the topical treatment of allergic diseases of the eye or nose.
SUMMARY OF THE INVENTION
The present invention provides methods for preventing or treating allergic diseases of the eye, nose, skin, ear, gastrointestinal tract, airways or lung. The methods may also be used to treat manifestations of systemic mastocytosis. The methods of the present invention comprise topically or systemically administering to a patient a mast cell stabilizing disulfide derivative of the formula
wherein X is —C(═O)—N(—R 1 )—R;
R and R 1 are independently H; (un)substituted phenyl; (un)substituted benzyl; or C 1 -C 8 alkyl or alkenyl, optionally substituted with or terminated by OH, OR 2 , NR 3 R 4 ; C 4 -C 7 cycloalkyl, (un)substituted aryl, or (un)substituted 5-7 membered heterocyclic ring; where optional substituents are selected from the group consisting of C 1 -C 6 alkyl or alkoxy; halogen; OH; CN; CF 3 ; NO 2 ; and CO 2 R 2 ;
R 2 is C 1 -C 3 alkyl; and
R 3 and R 4 are independently H; benzyl; C 1 -C 8 alkyl or alkenyl; C 4 -C 7 cycloalkyl; (un)substituted aryl; or (un)substituted 5-7 membered heterocyclic ring; wherein optional substituents are selected from the group consisting of C 1 -C 6 alkyl or alkoxy; halogen; OH; CN; CF 3 ; NO 2 ; and CO 2 R 2 .
The present invention is also directed toward topically or systemically administrable compositions for treating or preventing allergic diseases of the eye, nose, skin, ear, gastrointestinal tract, airways or lung and treating or preventing manifestations of systemic mastocytosis, wherein the compositions comprise a disulfide derivative of formula (I).
DETAILED DESCRIPTION OF THE INVENTION
The disulfide derivatives of formula (I) are known or are commercially available from sources such as Aldrich Chemical Company (Sigma Aldrich Library of Rare Chemicals) in Milwaukee, Wis. and Maybridge Chemical Company Ltd. in the U.K or can be made using known techniques, such as those described in Domagala J M et al. Biorganic and Medicinal Chemistry volume 5 No. 3 pages 569-79 (1997), and U.S. Pat. No. 4,705,805 (Yamotsu K. et al., 1987). The entire contents of both of these references are incorporated by reference.
Preferred compounds of formula (I) are those having the X substituents in the ortho position.
Most preferred are compounds wherein R and R 1 independently=H; C 1 -C 5 alkyl or alkenyl, optionally substituted with or terminated by OH, OR 2 NR 3 R 4 , C 4 -C 7 cycloalkyl, (un)substituted aryl, or (un)substituted 5-7 membered heterocyclic ring, wherein optional substituents are selected from the group consisting of C 1 -C 6 alkyl or alkoxy; halogen; OH; CN; CF 3 ; NO 2 ; and CO 2 R 2 .
Compounds of formula (I) may be administered topically (i.e., local, organ-specific delivery) or systemically by means of conventional topical or systemic formulations, such as solutions, suspensions or gels for the eye and ear; nasal sprays or mists for the nose; metered dose inhalers for the lung; solutions, gels, creams or lotions for the skin; oral dosage forms including tablets or syrups for the gastrointestinal tract; and parenteral dosage forms including injectable formulations. The concentration of the compound of formula (I) in the formulations of the present invention will depend on the selected route of administration and dosage form. The concentration of the compound of formula (I) in topically administrable formulations will generally be about 0.00001 to 5 wt. %. For systemically administrable dosage forms, the concentration of the compound of formula (I) will generally range from about 10 mg to 1000 mg.
The preferred formulation for topical ophthalmic administration is a solution intended to be administered as eye drops. For solutions intended for topical administration to the eye, the concentration of the compound of formula (I) is preferably 0.0001 to 0.2 wt. %, and most preferably from about 0.0001 to 0.01 wt. %. The topical compositions of the present invention are prepared according to conventional techniques and contain conventional excipients in addition to one or more compounds of formula (I). A general method of preparing eye drop compositions is described below:
One or more compounds of formula (I) and a tonicity-adjusting agent are added to sterilized purified water and if desired or required, one or more excipients. The tonicity-adjusting agent is present in an amount sufficient to cause the final composition to have an ophthalmically acceptable osmolality (generally about 150-450 mOsm, preferably 250-350 mOsm). Conventional excipients include preservatives, buffering agents, chelating agents or stabilizers, viscosity-enhancing agents and others. The chosen ingredients are mixed until homogeneous. After the solution is mixed, pH is adjusted (typically with NaOH or HCl) to be within a range suitable for topical ophthalmic use, preferably within the range of 4.5 to 8.
Many ophthalmically acceptable excipients are known, including, for example, sodium chloride, mannitol, glycerin or the like as a tonicity-adjusting agent; benzalkonium chloride, polyquaternium-1 or the like as a preservative; sodium hydrogenphosphate, sodium dihydrogenphosphate, boric acid or the like as a buffering agent; edetate disodium or the like as a chelating agent or stabilizer; polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid, polysaccharide or the like as a viscosity-enhancing agent; and sodium hydroxide, hydrochloric acid or the like as a pH controller.
If required or desired, other drugs can be combined with the disulfide derivatives of formula (I), including, but not limited to, antihistaminic agents, anti-inflammatory agents (steroidal and non-steroidal), and decongestants. Suitable antihistaminic agents include emedastine, mapinastine, epinastine, levocabastine, loratadine, desloratadine, ketotifen, azelastine, cetirazine, and fexofenadine. The preferred antihistaminic agent for ophthalmic use is emedastine, which is generally included in topically administrable compositions at a concentration of 0.001-0.1 wt. %, preferably 0.05 wt. %. Suitable anti-inflammatory agents include mometasone, fluticasone, dexamethasone, prednisolone, hydrocortisone, rimexolone and loteprednol. Suitable decongestants include oxymetazoline, naphazoline, tetrahydrozoline, xylometazoline, propylhexedrine, ethyinorepinephrine, pseudoephedrine, and phenylpropanolamine.
According to the present invention, the disulfide derivatives of formula (I) are useful for preventing and treating ophthalmic allergic disorders, including allergic conjunctivitis, vernal conjunctivitis, vernal keratoconjunctivitis, and giant papillary conjunctivitis; nasal allergic disorders, including allergic rhinitis and sinusitis; otic allergic disorders, including eustachian tube itching; allergic disorders of the upper and lower airways, including intrinsic and extrinsic asthma; allergic disorders of the skin, including dermatitis, eczema and urticaria; allergic disorders of the gastrointestinal tract, including systemic anaphylaxis resulting from ingestion of allergen and iatrogenic anaphylaxis caused by contrast agents used during diagnostic imaging procedures; and manifestations of systemic mastocytosis including hypotension.
The following examples are intended to be illustrative but not limiting.
EXAMPLE 1
Topical Ophthalmic Solution Formulation
Ingredient
Concentration (wt. %)
Compound of formula (I)
0.0001 to 0.2
Dibasic Sodium Phosphate (Anhydrous)
0.5
Sodium Chloride
0.65
Benzalkonium Chloride
0.01
NaOH/HCl
q.s. pH 6-8
Purified Water
q.s. 100
EXAMPLE 2
Topical Ophthalmic Gel Formulation
Ingredient
Concentration (wt. %)
Compound of formula (I)
0.0001 to 0.2
Carbopol 974 P
0.8
Edetate Disodium
0.01
Polysorbate 80
0.05
Benzalkonium Chloride
0.01
NaOH/HCl
q.s. pH 6-8
Water for Injection
q.s. 100
EXAMPLE 3
Synthesis of 2, 2-dithio-bis(N-3-morpholinopropyl-benzamide) (II)
2,2-Dithiodibenzoic acid chloride (1.5 g, 4.37 mmol ) was dissolved in 10 ml of dioxane and cooled to 10° C. To this solution, 4-(3-aminopropyl)morpholine (1.3 ml, 8.74 mmol) was added slowly under nitrogen. The resulting mixture was stirred at 10° C. for 1 hr and then at 70° C. for 2 hr. After cooling, the solids were filtered off. The filtrate was placed at room temperature. Yellowish solids precipitated and were filtered. The crude product was recrystallized with ethanol/ethyl ether (1:3), giving 0.80 g of white product (II).
1 H NMR (CDCl 3 ) δ8.04-7.18 (m, 8H), 3.73-3.54 (m, 12H), 2.60-2.39 (m, 12H), 1.87-1.80 (m, 4H). 13 C NMR (CDCl 3 ) δ167.63 (C═O), 137.32 (C), 134.23 (C), 131.07 (CH), 127.25 (CH), 127.17 (CH), 125.92 (CH), 66.91 (CH 2 ), 58.49 (CH 2 ), 53.74 (CH 2 ), 40.35 (CH 2 ), 24.21 (CH 2 ). Analysis calculated for C 28 H 38 O 4 N 4 S 2 requires: C, 60.19; H, 6.85; N, 10.03%. Found: C, 60.15; H, 6.82; N, 9.96%.
EXAMPLE 4
Mast Cell Activity
Preparation of Cell Suspension
Methods detailing preparation of mono-dispersed HCTMC and mediator release studies with these cells have been described (U.S. Pat. No. 5,360,720 and Miller et al, Ocular Immunology and Inflammation, 4(1):39-49 (1996)). Briefly, human conjunctival tissue mast cells were isolated from post-mortem tissue donors obtained within 8 hours of death by various eye banks and transported in Dexsol® corneal preservation medium, or equivalent. Tissues were enzymatically digested by repeated exposure (30 min. at 37° C.) to collagenase and hyaluronidase (2× with 200 U each/gram tissue, then 2-4 × with 2000 U each/gram tissue) in Tyrode's buffer containing 0.1% gelatin. (Tyrode's buffer (in mM): 137 NaCl, 2.7 KCl, 0.35 NaH 2 PO4, 1.8 CaCl 2 , 0.98 MgCl 2 , 11.9 NaHCO 3 , and 5.5 glucose). Each digestion mixture was filtered over Nitex® cloth (100 μm mesh, Tetko, Briarcliff Manor, N.Y.) and washed with an equal volume of buffer. Filtrates were centrifuged at 825×g (7 min). Pellets were resuspended in buffer then combined for enrichment over a 1.058 g/L Percoll® cushion. The enriched pellet was washed, resuspended in supplemented RPMI 1640 medium and incubated at 37° C. to equilibrate.
Histamine Release Studies
Cells were harvested from the culture plate and counted for viability (trypan blue exclusion) and mast cell number (toluidine blue O). Mast cells (5000/tube; 1 mL final volume) were challenged (37° C.) for 15 min with goat-anti-human IgE (10 μg/mL) following treatment (15 minutes; 37° C.) with test drug or Tyrode's buffer. Total and non-specific release controls were exposed to 0.1% Triton X-100 and goat IgG (10 μg/mL), respectively. The reaction was terminated by centrifugation (500×g, 4° C., 10 min). Supernatants were stored at −20° C. until analyzed for histamine content by RIA (Beckman Coulter, Chicago, Ill.).
Preparation of Test Drug Solutions
All test drugs were made to solution immediately prior to use. Each was dissolved in DMSO at 10 mM or greater concentration and then diluted in Tyrode's buffer containing 0.1% gelatin over the concentration for evaluation.
Data Analysis
Inhibition of histamine release was determined by direct comparison of with anti-IgE challenged mast cells using Dunnett's t-test (Dunnett, “A multiple comparison procedure for comparing treatments with a control”, J. Amer. Stat. Assoc. (1955), 50:1096-1121). An IC50 value (the concentration at which the test compound inhibits histamine release at a level of 50% compared to the positive control) was determined by 4-parameter logistic fitting using the Levenburg-Marquardt algorithm or by linear regression. The results are reported in Table 1.
TABLE 1
COMPOUND
NO.
T
X
MOLSTRUCTURE
IC50(nM)
1
S—S
39
2
S—S
78 199 39 [105]
3
S—S
21 388 231 121 141 9 128 [148]
4
S—S
39 69 1700 140 95 409 149 66 60 90 [282]
5
S—S
107 219 229 84 71 [122]
6
S—S
402 222 [312]
The data shown in Table 1 indicate that the compounds of formula (I) potently inhibit histamine release from human conjunctival mast cells in an in vitro model of allergic conjunctivitis.
EXAMPLE 5
Topical Ophthalmic Solution Formulation
Ingredient
Concentration (wt. %)
Compound of formula (I)
0.0001 to 0.2
Emedastine
0.001 to 0.1
Dibasic Sodium Phosphate (Anhydrous)
0.5
Sodium Chloride
0.65
Benzalkonium Chloride
0.01
NaOH/HCl
q.s. pH 6-8
Purified Water
q.s. 100
The invention has been described by reference to certain preferred embodiments; however, it should be understood that it may be embodied in other specific forms or variations thereof without departing from its spirit or essential characteristics. The embodiments described above are therefore considered to be illustrative in all respects and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description. | Methods and compositions for preventing or treating allergic diseases of the eye, nose, skin, ear, gastrointestinal tract, airways or lung and preventing or treating manifestations of systemic mastocytosis are disclosed. The compositions contain a mast cell stabilizing disulfide derivative as an active ingredient. |
CROSS-REFERENCE
This application is a continuation of U.S. patent applications Ser. No. 10/115,315 now U.S. Pat. No. 6,719,005 and Ser. No. 10/115,149, now U.S. Pat. No. 6,691,512 both filed Apr. 3, 2002. These prior applications are incorporated herein in their entirety by reference.
BACKGROUND OF THE INVENTION
This invention relates generally to the design of valves and, more particularly, to the design of a combination check valve and pressure relief valve.
In the art, check valves and pressure relief valves are known. Generally, a check valve functions to restrict flow in one direction while a relief valve is used to regulate flow pressure. Furthermore, U.S. Pat. No. 4,948,092 discloses a combined check valve and pressure relief valve having a resilient duckbill valve body. Fluid passing through a cylindrical core around a valve actuator functions to open the lips of the duckbill valve body to permit the free flow of the fluid while back pressure functions to seal the lips of the duckbill valve. Manual depression of the valve actuator, however, causes the valve actuator to penetrate and open the valve lips to selectively permit backflow to provide the relief valve function.
A further combination check valve and pressure relief valve is shown in prior art FIG. 13 . As illustrated, the combination check valve and pressure relief valve includes a check compression spring 78 and a relief compression spring 81 . The check compression spring 78 and relief compression spring 81 cooperate with a valve stem 82 , a machined valve seat 83 , and valve plug assembly 80 to provide the check valve and pressure relief functions. To establish the opening characteristics of the valve, a wet set procedure is utilized which involves setting the valve in a test stand and using fluid to activate the valve. The valve configuration is then adjusted, for example by turning a set screw, until the valve shows the desired amount of opening, based either on flow, or pressure, or both. While this wet set process works for its intended purpose, it does suffer the disadvantages of being time consuming and expensive. The use of a machined valve seat also increases the relative cost of the valve while further disadvantageously limiting the physical characteristics that can be provided to the valve seat. Still further, the large size of the compression spring 81 , disadvantageously requires the machining of holes in the valve seat to provide a means for relief fluid flow (since the size of spring 81 provides no fluid flow passages through spring 81 ). The size of spring 81 additionally increases the overall size of the valve assembly thereby preventing use of this valve in applications such as integrated hydrostatic transaxles.
SUMMARY OF THE INVENTION
To overcome these, and other disadvantages, a combination check valve and pressure relief valve is provided for use in regulating the flow of fluid between a first fluid side and a second fluid side. The combination check valve and pressure relief valve includes a valve plug, a valve guide moveably positioned in relation to the valve plug, a valve stem engaged to the valve guide, a check compression spring attached to the valve stem and positioned between the valve guide and the valve plug, a valve seat carried by the valve stem, and a relief compression spring positioned between the valve seat and the valve guide. The valve guide is adapted to move the valve stem relative to the valve seat against the force of the relief compression spring to allow fluid to pass from the first fluid side to the second fluid side through a fluid flow passage formed between the valve stem and the valve seat. Furthermore, the valve seat, valve stem, and valve guide are adapted to move relative to the valve plug against the force of the check compression spring to thereby remove the valve seat from an opening formed between the second fluid side and the first fluid side to permit fluid to pass through the opening.
Advantageously, a dry set procedure is used to set the valve configuration. Furthermore, a valve seat having complex geometries may be manufactured using metal injection molding. A better understanding of these and other advantages, objects, features, properties and relationships of the invention will be obtained from the following detailed description and accompanying drawings which set forth illustrative embodiments and which are indicative of the various ways in which the principles of the invention may be employed.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, reference may be had to a preferred embodiment shown in the following drawings in which:
FIG. 1 illustrates a rear view of a tractor using an exemplary transmission constructed in accordance with the subject invention;
FIG. 2 illustrates a cross-sectional, front view of the transmission of FIG. 1;
FIG. 3 illustrates a side view of the transmission of FIG. 1 with the side housing removed to expose certain components;
FIG. 4 illustrates a cross-sectional back view of the transmission along line D—D of FIG. 3 with the components missing from FIG. 3 restored;
FIG. 5 illustrates a side view of a combination check valve and pressure relief valve and a valve plug useable in connection with the end cap of FIG. 12;
FIG. 6 illustrates a cross-sectional view of the combination check valve and pressure relief valve along line B—B of FIG. 5;
FIG. 7 illustrates a front view of the combination check valve and pressure relief valve of FIG. 5 without a valve plug;
FIG. 8 illustrates a cross-sectional view of the combination check valve and pressure relief valve along line C—C of FIG. 7;
FIG. 9 illustrates an exploded view of the combination check valve and pressure relief valve of FIGS. 5-8 including a valve plug;
FIG. 10 is a flow chart diagram of exemplary steps used to configure the combination check valve and pressure relief valve of FIGS. 5-8;
FIG. 11 illustrates a cross-sectional view of a center section for a single pump hydrostatic transmission in which the combination check valve and pressure relief valve of FIGS. 5-8 is installed taken along line A—A of FIG. 2;
FIG. 12 illustrates a cross-sectional view of a center section for a dual pump hydrostatic transmission in which the combination check valve and pressure relief valve of FIGS. 5-8 is installed; and
FIG. 13 illustrates a prior art combination check valve and pressure relief valve.
DETAILED DESCRIPTION
Turning now to the figures, wherein like reference numerals refer to like elements, there is generally illustrated in FIGS. 5-9 a combination check valve and pressure relief valve 10 . While the combination check valve and pressure relief valve 10 will be described in the context of a hydrostatic transmission, it is to be understood that this description is not intended to be limiting. Rather, from the description that follows, those of ordinary skill in the art will appreciated that the combination check valve and pressure relief valve 10 may be utilized in connection with a myriad of additional applications.
With reference to FIGS. 1-4, the combination check valve and pressure relief valve 10 is particularly suited for used in connection with a hydraulic circuit of a hydrostatic transmission 12 . In this regard, the hydrostatic transmission 12 generally operates on the principle of an input shaft 14 rotatably driving a hydraulic pump 16 which, through the action of its pump pistons 18 , pushes hydraulic fluid to a hydraulic motor 20 through a center section 22 to cause the rotation of the hydraulic motor 20 . The rotation of the hydraulic motor 20 causes the rotation of a motor shaft 24 which rotation is eventually transferred through a gearing system or the like 25 to drive one or a pair of axle shafts 26 . A motive force may be supplied directly to the input shaft 14 or indirectly by means of pulleys and belts which are connected to an internal combustion engine. For a more detailed description of the principles of operation of such a hydrostatic transmission, the reader is referred to U.S. Pat. Nos. 5,201,692, and 6,322,474 which are incorporated herein by reference in their entirety.
For placing the hydraulic pump 16 in fluid communication with the hydraulic motor 20 , the center section 22 includes hydraulic porting. The hydraulic porting is in further fluid communication with a source of makeup fluid, such as a fluid sump or a charge gallery. Generally, the hydraulic porting comprises a high pressure side through which fluid moves from the hydraulic pump 16 to the hydraulic motor 20 and a low pressure side through which fluid returns from the hydraulic motor 20 to the hydraulic pump 16 . Since fluid tends to leak from the hydraulic porting, the hydraulic pump 16 generally requires more fluid than is returned from the hydraulic motor 20 via the low pressure side porting. This requirement for fluid may, however, be satisfied by using the combination check valve and pressure relief valve 10 . Generally, the combination check valve and pressure relief valve 10 functions to prevent the flow of fluid from the hydraulic porting to the source of makeup fluid while allowing fluid to flow from the source of makeup fluid into the hydraulic porting when the fluid pressure in the hydraulic porting is lower relative to the fluid pressure in the source of makeup fluid. In cases where the fluid pressure in the porting is excessive, determined on a application by application basis, the combination check valve and pressure relief valve 10 further functions to relieve this excess fluid pressure by allowing fluid to be discharged from the hydraulic porting to the source of makeup fluid.
To this end, the combination check valve and pressure relief valve 10 may be mounted in the center section 22 between a first fluid side A and second fluid side B. In the application described herein, the first fluid side A is associated with the source of makeup fluid while the second fluid side B is associated with the porting that provides a fluid path between the hydraulic pump 16 and hydraulic motor 20 . By way of example, FIG. 11 illustrates the combination check valve and pressure relief valve 10 installed in an exemplary center section 22 for a single pump hydrostatic transmission carried as part of an integrated hydrostatic transaxle. FIG. 12 illustrates the combination check valve and pressure, relief valve 10 installed in an exemplary center section for a dual pump hydrostatic transmission which may used in connection with a stand-alone hydrostatic transmission. It will be understood, however, that these illustrated embodiments are not intended to be limiting. Rather, the combination check valve and pressure relief valve 10 may be used in connection with any closed hydraulic circuit where there is a need for makeup fluid.
To secure the combination check valve and pressure relief valve 10 in the center section 22 , a valve plug 30 may be threaded to mate with corresponding threads provided in the center section 22 as illustrated in FIG. 12 . As further illustrated in FIG. 12, an O-ring 32 may be provided to prevent the leakage of fluid from the junction between the combination check valve and pressure relief valve 10 and the center section 22 . Other manners for securing the combination check valve and pressure relief valve 10 in the center section 22 are also contemplated. For example, as illustrated in FIG. 11, the valve plug 30 ′ may be carried within a threaded insert 22 A that is to be considered a part of the center section 22 . In this case, a retaining ring 21 may also be utilized to maintain the valve plug 30 ′ within the threaded insert 22 A.
To allow for the flow of fluid from fluid side A to fluid side B when fluid side B is under lower pressure relative to fluid side A, the combination check valve and pressure relief valve 10 includes a check compression spring 34 as illustrated in FIGS. 5-9. In this regard, the check compression spring 34 is positioned between the valve plug 30 and a valve guide 36 which is carried within and moveable with respect to the valve plug 30 . The valve guide 36 is, in turn, attached to a valve stem 38 which cooperatively engages a valve seat 40 . The check compression spring 34 may be attached to the valve stem 38 by providing the compression spring 34 with a portion 35 having a diameter sized to mate with grooves or threads formed on a first end 38 a of the valve stem 38 , as illustrated in FIG. 8 .
More specifically, when the force on the valve stem 38 caused by the fluid pressure differential is sufficient to overcome the restoring force of the check compression spring 34 , the fluid pressure differential will influence the valve stem 38 and the attached valve guide 36 to compress the check compression spring 34 into the valve plug 30 . During this movement of the valve stem 38 , an enlarged portion 38 b of the valve stem 38 engages a second surface 40 b of the valve seat 40 and causes the valve seat 40 to move away from a valve seat surface 42 formed in the center section 22 . The valve seat surface 42 can be integrally formed with the center section 22 as illustrated in FIG. 12 or may be a part of the threaded insert 22 A as illustrated in FIG. 11 . In this manner, the movement of the valve seat 40 away from the valve seat surface 42 breaks a sealing engagement between the valve seat 40 and the valve seat surface 42 to allow the fluid under pressure in fluid side A to flow into fluid side B through an opening defined within the valve seat surface 42 .
Once the pressure differential and flow of fluid from fluid side A is no longer sufficient to overcome the restoring force of the compression check spring 34 , the compression check spring 34 return force urges the valve guide 36 and valve stem 38 back towards the valve seat surface 42 . This movement of the valve guide 36 and valve stem 38 functions to return the valve seat 40 into sealing engagement with the valve seat surface 42 to thereby prevent the flow of fluid through the opening defined by the valve seat surface 42 . In this regard, the valve scat 40 moves with the valve guide 36 and valve stem 38 owing to a relief compression spring 44 which is disposed around the valve stem 38 between the valve guide 36 and the valve seat 40 and which generally biases the valve seat 40 against the enlarged portion 38 b of the valve stem 38 when the valve seat 40 is not engaged with the valve seat surface 42 .
To allow for the flow of fluid from fluid side B to fluid side A when the fluid in fluid side B is under excessively high pressure relative to the fluid in fluid side A, a flow passage 38 c is formed in the valve stem 38 . While not intended to be limiting, the flow passage 38 c is illustrated as being a reduced diameter portion formed in the valve stem 38 that cooperates with an opening in the valve seat 40 . In particular, when the force resulting from the fluid pressure differential is sufficient to overcome the restoring force of the relief compression spring 44 , the valve stem 38 is caused to move relative to the valve seat 40 , which is normally in sealing engagement with the valve seat surface 42 , such that the end of flow passage 38 c extends beyond the valve seat 40 to thereby allow fluid to flow from fluid side B to fluid side A through the flow passage 38 c.
For allowing the valve stern 38 to move as a result of the excess pressure in fluid side B, a small gap (for example, 0.004 to 0.009 inches diametrically) is provided between the valve guide 36 and the valve plug 30 . This gap allows fluid to flow into the space B′ formed behind the valve guide 36 . In this manner, when the pressure within the space B′ behind the valve guide 36 builds to a certain point, which is established primarily by the hole diameter in the valve seat 40 and rate of the relief compression spring 44 , the fluid pressure differential causes the valve stem 38 and the attached valve plug 30 to move and compress the relief compression spring 44 in the manner described above. As further illustrated in FIG. 11, the valve plug 30 ′ may be provided with fins that provide fluid access around valve plug 30 ′ to the volume behind the valve guide 36 (as illustrated by the arrows in FIG. 11) while also providing stability to the moving valve guide 36 .
As pressure continues to build in fluid side B relative to fluid side A, the valve guide 36 is compressed further, the valve stem 38 moves further relative to the valve seat 40 , and more of the fluid flow passage 38 c is exposed to fluid side A. Thus, the opening of fluid side B to fluid side A via the fluid flow passage 38 c is not abrupt, and pressure can continue to build in fluid side B. However, this pressure build up is at a steadily decreasing rate as compared to a hydraulic circuit in which no combination check valve and relief valve 10 is utilized.
Disadvantageously, the flow of fluid through the flow passage 38 c can set up an oscillatory motion which, in some cases, can be detected as a vibration or pulse in certain applications such as hydrostatic transmissions. The small gap between the valve guide 36 and the valve plug 30 , however, functions to reduce or eliminate such oscillatory movement. In particular, this results from the time it takes for the fluid to move into and out of the space B′ behind the valve guide 36 .
When the fluid pressure differential is no longer sufficient to overcome the restoring force of the relief compression spring 44 , the relief compression spring 44 forces the valve guide 36 and attached valve stem 38 back towards the valve plug 30 . This movement of the valve stem 38 causes the fluid flow passage 38 c to move back into the valve seat 40 . This movement of the fluid flow passage 38 c back towards the valve seat 40 causes less of the fluid flow passage 38 c to be exposed to fluid side A until such time as the valve stem 38 sealingly engages the valve seat 40 to close the fluid flow passage 38 c . It will be appreciated that the movement of the valve stem 38 under the influence of the relief compression spring 44 is dampened as the movement of the valve guide 36 towards the valve plug 30 causes fluid to be forced from the volume behind the valve guide 36 through the gap between the valve guide 36 and the valve plug 30 .
To reduce cost, the valve seat 40 of the combination check valve and pressure relief valve 10 is preferably manufactured using a metal injection molding (“MIM”) process. The metal injection molding process also allows the valve seat 40 to be provided with a bleed orifice 46 , a rib structure 48 (which provides fluid access passageways to the center opening in the valve seat 40 as well as engagement surfaces for the spring 44 ), and the opening configuration that cooperates with the fluid flow path 38 c . Importantly, the MIM process allows the small bleed orifice 46 to be provided with orifice diameters depending upon the application in which the combination check valve and pressure relief valve 10 is to be utilized by easily changing inserts used in the MIM process. It would be extremely difficult and costly to machine the valve seat 40 to achieve the features above described.
Cost of assembly of a hydrostatic transmission utilizing the described combination check valve and pressure relief valve 10 is also reduced. In this regard, since the check compression spring 34 is attached to the back end 38 a of the valve stem 38 , the combination check valve and pressure relief valve 10 can be installed using a simplified process. To this end, the valve plug 30 as shown in FIG. 12 need only be installed after the configured components of the check valve and pressure relief valve 10 are dropped into the center section 22 . Note that the O-ring would be positioned on the valve plug 30 at the time of assembly. In contrast, prior techniques for installing valves required springs, such as spring 78 in prior art FIG. 13, to be installed loosely into a device. Thus, the presently described manner of assembly also has the advantage of generally eliminating the risk that the parts are misassembled or that the spring 34 becomes loose within the hydraulic circuit.
To configure the combination check valve and pressure relief valve 10 for use in connection with a given application, a dry set procedure, as illustrated in FIG. 10, may be utilized. The dry set procedure is utilized to set the relief compression spring 44 to a certain spring compression within the assembled valve 10 to allow the valve 10 to operate with a particular pressure and to provide a specific amount of fluid flow through the fluid flow path 38 c at a particular pressure. The dry set procedure is performed by selecting a compression spring 44 that has a spring rate that is believed will provide the desired fluid flow at a desired opening pressure considering the valve stem diameter. The spring compression force required to achieve the desired opening pressure using the actual spring rate chosen is then calculated in a manner well known to those of skill in the art. The valve guide 36 is then moved to a point where the compression spring 44 is compressed between the valve guide 36 and the valve seat 40 at the calculated compression force upon which the valve guide 36 is crimped to attach the valve guide 36 to the valve stem 38 .
The valve 10 may then be tested to ensure that the proper spring rate and the proper valve guide 36 set position were selected to achieve the desired flow rate. This testing may be performed by installing the valve 10 in a test stand to measure the pressure required to achieve the required flow rate. If the testing proves successful, production parts can be manufactured using the selected spring rate and valve guide set position. While this dry set procedure is not as accurate as using fluid to set the opening point of the valve, the dry set procedure does give adequate tolerances for hydrostatic transmission application (e.g., approximately +/−9% psi variation from valve to valve). It is contemplated that the dry-set procedure may be modified to improve these tolerances if needed for a given application. By way of example, the compression spring 44 can be set in a manner where the influence of frictional forces are minimized.
While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. For example, while the valve 10 is illustrated as being positioned in the forward side of an hydraulic circuit, it will be appreciate that such a valve 10 can also be positioned in the reverse side of an hydraulic circuit. Accordingly, the particular arrangement disclosed is meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any equivalents thereof. | A method of configuring a valve comprised of a valve seat, a valve stem, a valve guide, and a relief compression spring. The method comprises calculating a compression force required to move the valve stem relative to the valve seat, using that calculated force to move the valve guide into a desired position, then crimping the valve guide to the valve stem at that desired position. The method also comprises attaching a check compression spring to the valve stem at a location inside the valve guide, installing the valve in a test stand to measure the actual pressure required to achieve the desired rate of fluid flow and forming the valve seat using metal injection molding. |
PRIORITY CLAIM
[0001] Priority is claimed to provisional application No. 66165502 filed Apr. 3, 2009.
BACKGROUND OF THE INVENTION
[0002] The present invention relates in general to latching mechanisms which are designed to securely connect one object to another object, such as a boat to a boat trailer. More specifically, the present invention is an automatic latching and releasing mechanism, which may be mounted on an appropriately equipped boat trailer, and latches or releases the securing eye of a boat.
[0003] Numerous attempts have been made in recent decades to solve the inconvenience and risk of injury associated with the present commonly used method of securing a boat to a trailer with a winch, strap and hook. This method usually entails the manual cranking of a winch to draw or release a strap that may be connected to a hook that may be hooked to the securing eye on the centerline of the bow of a boat. It typically requires an individual to access the point at which the boat and the trailer come in contact while the boat is in the water by wading in the water, leaning over the bow of the boat or climbing onto the tongue of the trailer. This current prevalent method is not only dangerous and inconvenient but is particularly difficult for one person to perform alone. It is also very difficult for an individual of limited strength to perform.
[0004] A few products are already on the market that are designed to solve the problems associated with trailering a boat.
[0005] A boat latch sold under the trademark SNAPPER, manufactured by EPCO Products, Inc., Fort Wayne, Ind. is an electronically controlled attachment device that entered the market within the last 2 years. The device is cumbersome to install due its design and electrical hook up necessity as well expensive and vulnerable due to the electronics near a water environment.
[0006] A boat latch sold under the trademark BOAT BUDDY, manufactured by ROECO, Inc. Fort Worth, Tex. is a simple and inexpensive device that attaches a boat to a trailer but does not offer an effective or convenient way to release the boat from the trailer. In effect, this device creates as much inconvenience in releasing a boat from a trailer as it creates convenience in connecting the two.
[0007] Another product on the market is the boat latch sold under the trademark LAUNCH AND RETRIEVE BOAT LATCH manufactured by Release & Retrieve Boat Latch Pty Ltd, Adelaide, Australia. This product incorporates a latch that is offset from a boat's centerline and utilizes a unique eyehook on a boat's bow. Incumbent to the product's design is the necessity to change the typical eye hook found on most modern boats which can be a cumbersome exercise. Also disadvantageous to this product is that its design forces a boat's bow off center in order to latch putting lateral pressure on the boat trailer's guides causing potential damage.
[0008] A wide variety of mechanisms have been designed using clasps, pins and hooks to automatically secure a boat to a trailer. Most are designed to eliminate the need for an individual to access the point of contact between boat and trailer while the boat is in the water when loading a boat onto a trailer. While one common element among most is their use of the securing eye that is standard equipment on most boats, other elements of prior designs vary widely.
[0009] One such earlier design for latching a boat to a trailer was a mechanism using a spring-loaded pin represented in U.S. Pat. No. 4,919,446 which was issued Apr. 24, 1990 to Higgins. This design, however, does not provide an automatic releasing mechanism and does not provide a secondary securing member to restrict movement of the boat's eyehook toward the tow vehicle.
[0010] Another earlier design for latching a boat to a trailer was a mechanism using a spring-loaded pin represented in U.S. Pat. No. 3,989,267 which was issued Nov. 2, 1976 to Robinson. This design, however, does not provide an automatic latching or release mechanism, is difficult to attach to a typical modern boat trailer, does not employ a bow guide, does not provide a secondary securing member to restrict movement of the boat's eyehook toward the tow vehicle, and eliminates the potential use of the traditional winch apparatus.
[0011] Another such earlier design is represented in U.S. Pat. No. 5,120,079 issued Jun. 9, 1992 to Boggs. The novelty of this design was in the bow guide used to protect the boat and invention. And while a locking pin mechanism was used, no automatic release mechanism was employed and no secondary securing member to restrict movement of the boat's eyehook toward the tow vehicle is described.
[0012] Another earlier design which used a spring loaded pin is represented in U.S. Pat. No. 4,114,920 issued Sep. 19, 1978 to Boettcher. While a spring loaded pin assembly was used in combination with a bow guide, neither a release mechanism nor the ability to use the winch and strap apparatus was possible and the trailer mounting design is complicated and adds numerous parts. Also, no secondary securing member to restrict movement of the boat's eyehook toward the tow vehicle is described.
[0013] Another earlier design which employs a spring loaded pin and a bow guide is U.S. Pat. No. 5,193,835 issued Mar. 16, 1993 to Sheets. This design, however, does not entail a simple to install, one piece designed apparatus that has an automatic release mechanism accompanying the securing mechanism nor a secondary securing member to restrict movement of the boat's eyehook toward the tow vehicle is described.
[0014] A more recent design which does not employ a pin mechanism but does have an automatic release mechanism is U.S. Pat. No. 6,923,138 issued Aug. 2, 2005 to Holbrook. The mechanism utilizes a motor driven rotating head on a shaft that protrudes from the bow of a boat and is captured and released by two steel plates. The mechanism is relatively complicated with numerous moving parts in various conditions. It also requires modification to the standard bow securing eye found on most boats and does not allow for the traditional winch, strap and hook method to be used as a back-up.
[0015] Referring to FIG. 1 , a side elevational view of a boat 12 loaded on a boat trailer 38 which includes a prior art latching mechanism. The boat 12 may be pulled up onto the boat trailer 38 by a securing eye 16 , such as an eyehook, by means of a hook attached to a strap 32 and retrieved by a winch 30 . The winch 30 may be powered by hand by means of a winch handle 31 or by electric motor and may be attached to a winch housing 34 by a bolt 40 . The centerline of the boat 12 may be guided by a roller 42 that may be mounted by means of a mounting bolt 66 at the end of a first winch arm extension 8 a and a second winch arm extension 8 b (not pictured) and keeps boat 12 's bow centered on the boat trailer 38 . The entirety of the prior art latching mechanism may be supported by a first winch pedestal 36 a and a second winch pedestal 36 b.
SUMMARY OF THE INVENTION
[0016] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated herein being contemplated as would normally occur to one skilled in the art to which the invention relates.
[0017] An example of embodiments of the present invention includes a body, made of corrosion resistant plastic or other composite, which features a lower mounting bracket that is adaptable to attach to most boat trailers by use of a single bolt, an upper “V” shaped boat bow guide that aligns a boat's bow section with a “V” shaped receiver that aligns the boat's securing eye with a securing member and a securing member release trigger. The body also houses the securing, or locking, or engaging, or closing mechanism and the releasing, or opening, or disengaging, or unlocking mechanism that includes an energy storage device biasing a securing member held in an open or closed condition by an energy storage device loaded trigger. Said trigger may be tripped by contact with a boat's securing eye either as the boat is being loaded onto the trailer or as the boat is being offloaded from the trailer into the water. When tripped, the trigger disengages from the securing member allowing said securing member to slide into either the opened or closed condition. The securing member may be biased by a biasing mechanism, through an energy storage device that can be set to move the securing member to an open condition or move the securing member to a closed condition within a securing member path and perpendicular to the V-shaped receiver. Said energy storage devices, securing members, biasing mechanism, and trigger may be made of corrosion resistant metal or other composite.
[0018] What is consistently absent from the prior art is an automatic releasing mechanism accompanying the securing mechanism. An embodiment of the present invention not only solves the problems associated with manually loading a boat onto a trailer using a novel mechanism, it also provides a safe, convenient, simple and reliable means of releasing a boat from a trailer. Embodiments of the present invention may be realized in an automatic boat latching and releasing apparatus. The body and accompanying latching mechanism of the present invention mounts on an appropriately equipped boat trailer and secures or releases the securing eye that may be mounted on the centerline of the lower bow section of most boats.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a side elevational view of a boat loaded on a boat trailer which includes a prior art latching mechanism.
[0020] FIG. 2 is a top perspective view is a latching and release mechanism according to one embodiment of the present invention.
[0021] FIG. 3 is a top perspective view of the FIG. 2 latching and releasing mechanism in a secured and ready-to-release condition.
[0022] FIG. 4 is a top perspective view of the FIG. 2 latching and releasing mechanism in a released condition.
[0023] FIG. 5 is a top perspective view of the FIG. 2 latching and releasing mechanism in a secured and ready-to-lock condition.
[0024] FIG. 6 is a top perspective view of the FIG. 2 latching and releasing mechanism in a secured and locked condition.
[0025] FIG. 7 is a top perspective view of the FIG. 2 latching and releasing mechanism in a loading condition.
[0026] FIG. 8 is a perspective view of the bottom surface of the housing.
[0027] FIG. 9 is a perspective view of the top surface of the housing.
[0028] FIG. 10 is a side perspective view with mounting assembly.
[0029] FIG. 11 is a side perspective view with mounting assembly with a boat.
[0030] FIG. 12 is a top perspective view with secondary securing member in a locked condition.
[0031] FIG. 13 is a top perspective view with secondary securing member in a released condition.
[0032] FIG. 14 is a top perspective view of a latching and release mechanism according to one embodiment of the present invention with the securing member in a locked condition.
[0033] FIG. 15 is a top perspective view of a latching and release mechanism according to one embodiment of the present invention with the securing member in a release condition.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] In reference to FIGS. 2-6 , an example of an embodiment of the present invention latching and releasing mechanism is illustrated. A housing 1 that includes a first bow guide 2 a and a second bow guide 2 b align the boat's centerline with a bow guide centerline 56 and a similarly oriented V-shaped receiver 14 . A trigger insert 4 c, biased by a secondary energy storage device 26 , such as a spring, alternately locks a securing member 52 by means of a first slot 50 a and a second slot 50 b subsequently restricting movement of securing member 52 unless and until a trigger 4 a is forced into a release condition. Said restricted movement of securing member 52 is persistent regardless of bias by a main energy storage device 22 , such as a spring, absent appropriate force to release trigger 4 a and attached trigger insert 4 c. Lateral movement of main energy storage device 22 is restricted by an energy storage device slot 58 . Trigger 4 a pivots on a pivot point 28 and can be made to release from securing member 52 by means of pressure from an advancing securing eye 16 (pictured in FIGS. 6 , 7 and 8 ) through a securing eye slot 54 or by use a trigger release 4 b. Said securing member 52 slides within energy storage device slot 58 and a securing member slot 62 upon the condition that the main energy storage device 22 biases said securing member 52 and the trigger 4 a is moved to the release condition. Said main energy storage device 22 pressures securing member 52 to be in a closed or open condition pursuant to pressure from a biasing mechanism 18 which consists of a biasing mechanism securing member 20 which is attached to a biasing mechanism handle 24 . Said biasing mechanism handle 24 may be moved to a condition in a first biasing mechanism slot 64 a or a second biasing mechanism slot 64 b. Movement of biasing mechanism securing member 20 may be guided by a biasing mechanism securing member slot 60 .
[0035] FIG. 2 illustrates an example of an embodiment of the present invention in a condition in which securing member 52 is closed and biasing mechanism 18 is in a locked condition, exemplified by biasing mechanism handle 24 being locked in position in first biasing mechanism slot 64 a closest to securing eye slot 54 as opposed to biasing mechanism handle 24 being in the open condition in second biasing mechanism slot 64 b. By means of securing member 52 , securing eye slot 54 is enclosed. Trigger 4 a is in a lock condition in second slot 50 b restricting securing member 52 in the closed condition and restricting said securing member 52 from sliding to the open condition within energy storage device slot 58 or securing member slot 62 . Main energy storage device 22 is slightly compressed by biasing mechanism securing member 20 in the lock condition and securing member 52 in the closed condition. Secondary energy storage device 26 is marginally compressed between housing 1 and trigger 4 a pressuring trigger insert 4 c to penetrate second slot 50 b. Manual trigger release 4 b is protruding from housing 1 .
[0036] FIG. 3 illustrates an example of an embodiment of the present invention in a condition in which securing member 52 is closed and biasing mechanism 18 is in the release condition, exemplified by biasing mechanism handle 24 being locked in position farthest from securing eye slot 54 in second biasing mechanism slot 64 b. By means of securing member 52 , securing eye slot 54 is enclosed in spite of contrary pressure from main energy storage device 22 . Trigger 4 a is in a lock condition in second slot 50 b restricting securing member 52 in the closed condition and restricting said securing member 52 from sliding to the open condition further into energy storage device slot 58 and out of securing member slot 62 . Main energy storage device 22 is fully stretched by biasing mechanism securing member 20 in the release condition and securing member 52 in the closed condition. Secondary energy storage device 26 is marginally compressed between housing 1 and trigger 4 a pressuring trigger insert 4 c to penetrate second slot 50 b.
[0037] FIG. 4 illustrates an example of an embodiment of the present invention in a condition in which securing member 52 is open and biasing mechanism 18 is in the release condition, exemplified by biasing mechanism handle 24 being locked in position farthest from securing eye slot 54 . Through the V-shaped receiver 14 , securing eye slot 54 is receptive to, or has released, securing eye 16 . Trigger 4 a is in a lock condition in first slot 50 a restricting securing member 52 in the open condition and restricting said securing member 52 from sliding to the closed condition within energy storage device slot 58 and into securing member slot 62 . Main energy storage device 22 is marginally stretched by biasing mechanism securing member 20 in the release condition and securing member 52 in the open condition. Secondary energy storage device 26 is marginally compressed between housing 1 and trigger 4 a pressuring trigger insert 4 c to penetrate first slot 50 a.
[0038] FIG. 5 illustrates an example of an embodiment of the present invention in a condition in which securing member 52 is open and biasing mechanism 18 is in the lock condition, exemplified by biasing mechanism handle 24 being locked in position closest to securing eye slot 54 . Through the V-shaped receiver 14 , securing eye slot 54 is receptive to, or has released, securing eye 16 . Trigger 4 a is in a lock condition in first slot 50 a restricting securing member 52 in the open condition and restricting said securing member 52 from sliding to the closed condition within energy storage device slot 58 and into securing member slot 62 . Main energy storage device 22 is fully compressed with energy storage device slot 58 by biasing mechanism securing member 20 in the lock condition and securing member 52 in the open condition. Secondary energy storage device 26 is marginally compressed between housing 1 and trigger 4 a pressuring trigger insert 4 c to penetrate first slot 50 a.
[0039] FIG. 6 illustrates a mirror image of FIG. 2 in aspects except that securing eye 16 is illustrated in a locked condition restricted by securing member 52 and enclosed within securing eye slot 54 .
[0040] FIG. 7 illustrates a mirror image of FIG. 6 in aspects except that the securing eye 16 has applied force through contact to trigger 4 a pushing trigger insert 4 c to disconnect from second slot 50 b. Said disconnect of trigger insert 4 c allows securing member 52 to move to the position biased by main energy storage device 22 , in this illustration, securing member 52 has remained in the closed condition. Upon release of the force by securing eye 16 , trigger insert 4 c may reconnect to a position in second slot 50 b. Regardless of the position of trigger insert 4 c however, pressure from main energy storage device 22 , biased by the lock condition of biasing mechanism securing member 20 in this illustration, may force securing member 52 to remain in the closed condition. This aspect of the design of the current invention is intentional and provides a safety measure by maintaining the closed condition of securing member 52 when biasing mechanism securing member 20 is in the lock condition thereby restricting the release of securing eye 16 from securing eye slot 54 regardless of the disposition of trigger insert 4 c.
[0041] FIG. 8 illustrates a perspective view of the bottom surface of housing 1 . Illustrated are the lower portion of the first bow guide 2 a and second bow guide 2 b. A Mounting bracket 6 is penetrated longitudinally by a mounting bolt slot 10 . Trigger 4 a is in the locked condition and securing member 52 is closed restricting movement from securing eye 16 out of securing eye slot 54 and into V-shaped receiver 14 . Manual trigger release 4 b is observable.
[0042] FIG. 9 is a perspective view of the top surface of housing 1 . First Bow guide 2 a and second bow guide 2 b are split perpendicularly by bow guide centerline 56 . V-shaped receiver 14 is aligned with bow guide centerline 56 . Securing member 52 is in the closed condition and trigger 4 a is in the lock condition. Biasing mechanism handle 24 is in the lock condition in first biasing mechanism slot 64 a exposing biasing mechanism securing member 20 , a portion of biasing mechanism 18 . Manual trigger release 4 b can be observed protruding from housing 1 . Second biasing mechanism slot 64 b is also observable.
[0043] FIG. 10 illustrates a side perspective view of the current invention as mounted on a boat trailer (not pictured). Mounting bolt 66 penetrates first winch arm extension 8 a and second winch arm extension 8 b through mounting bolt slot 10 and mounting bracket 6 securing the surface of the current invention close to parallel to the bow section of the boat (not pictured). First bow guide 2 a and second bow guide 2 b align the boats bow with V-shaped receiver 14 . Manual trigger release 4 b can be observed protruding from housing 1 .
[0044] FIG. 11 mirrors FIG. 10 with the exception that boat 12 has been illustrated and second bow guide 2 b and V-shaped receiver 14 are no longer visible behind boat 12 .
[0045] FIG. 12 represents a top perspective view of another embodiment of the current invention. A secondary securing member 70 may be employed within housing 1 to restrict movement toward the tow vehicle of securing eye 16 in V-shaped receiver 14 and securing eye slot 54 . Secondary securing member 70 may slide within a secondary energy storage device slot 73 and parallel to securing member 52 , energy storage device slot 58 and main energy storage device 22 and may be biased by a secondary securing member energy storage device 71 that may be attached to a biasing mechanism extension 72 which may be secured to biasing mechanism 18 . Biasing mechanism 18 may bias securing member 20 which may be guided by biasing mechanism securing member slot 60 and may bias secondary securing member 70 with biasing mechanism handle 24 in either first biasing mechanism slot 64 a or second biasing mechanism slot 64 b. Secondary securing member 70 may be in lock or release condition when securing member 52 is in the locked condition and may only be in the release condition when securing member 52 is in the release condition due to pressure from a securing member tip extension 52 a and within securing member slot 62 . Secondary securing member 70 may move independent of trigger 4 a, trigger manual release 4 b, trigger insert 4 c and secondary energy storage device 26 . In this illustration, secondary securing member 70 is in a locked condition, biasing mechanism 18 is in the lock condition with biasing mechanism handle 24 in first biasing mechanism slot 64 a.
[0046] FIG. 13 mirrors FIG. 12 with the exception that secondary securing member 70 has been biased to move to a release condition within secondary securing member slot 73 through bias by secondary securing member energy storage device 71 which may be biased by the movement of biasing mechanism extension 72 when biasing mechanism handle 24 is moved from first biasing mechanism slot 64 a to second biasing mechanism slot 64 b.
[0047] FIG. 14 illustrates another embodiment of the current invention using an alternate energy storage device. Main energy storage device 22 may rotate around a main energy storage device pivot 22 a biasing securing member 52 within biasing mechanism securing member slot 60 . Trigger 4 a may restrict the movement of securing member 52 dependent upon the position of trigger insert 4 c in either first slot 50 a or second slot 50 b. Trigger 4 a may rotate around trigger pivot 28 which may be tripped by the approaching securing eye 16 or manually using trigger manual release 4 b.
[0048] FIG. 15 mirrors FIG. 14 with the exception that main energy storage device 22 has rotated on Main energy storage device pivot 22 a biasing securing member 52 to move to a release condition, and trigger insert 4 c has moved from second slot 50 b to first slot 50 a.
[0049] While trigger 4 a, securing member 52 , biasing mechanism 18 and main energy storage device 22 all work together to secure or release a securing eye 16 , each works independently as well. A further explanation follows.
[0050] Biasing mechanism 18 has two preferred settings and may be set manually. The first setting is achieved when biasing mechanism handle 24 is positioned in the first biasing mechanism slot 64 a which is closest to the securing member slot 54 . This condition may be employed at all times other than when the boat is being launched and biases main energy storage device 22 to push securing member 52 toward the locked condition in securing member slot 62 . Securing member 52 may in fact be locked by trigger insert 4 c in an open condition when biasing mechanism 18 is in the locked condition until the trigger 4 a is tripped by the boat 12 securing eye 16 or manually by using trigger manual release 4 b. Upon the closing of securing member 52 while biasing mechanism 18 is in a locked condition with biasing mechanism handle 24 in first biasing mechanism slot 64 a, a small degree of bias from main energy storage device 22 will persist ensuring that securing member 52 remains closed in order to mitigate an unintended release of securing eye 16 .
[0051] The second preferred setting of the biasing mechanism 18 is achieved by moving biasing mechanism handle 24 away from securing member 52 into second biasing mechanism slot 64 b. This condition may be used when launching boat 12 or during maintenance of the invention. In this condition, biasing mechanism 18 biases main energy storage device 22 to retract securing member 52 when the trigger 4 a is tripped thereby unrestricting movement of securing eye 16 from securing slot 54 and toward V-shaped receiver 14 . Securing member 52 will remain, if initially so, in the closed condition unless and until the trigger 4 a is tripped.
[0052] A third setting for biasing mechanism 18 may be possible. In the event that biasing mechanism handle 24 is not deployed in one of the preferred settings in first biasing mechanism slot 64 a or second biasing mechanism slot 64 b, then main energy storage device 22 may convey no bias to securing member 52 .
[0053] There are two preferred securing member 52 conditions. The closed condition is preferred to be used whenever boat 12 is on the trailer, except during a period of the launching process, and securely attaches the boat 12 securing eye 16 to the boat trailer 38 . Said securing member 52 may be closed when trailering boat 12 , when backing boat 12 down the launch ramp and when driving boat 12 up the launch ramp after retrieval. The initial securing member 52 condition may be maintained in the closed condition, if so biased by main energy storage device 22 , by the trigger insert 4 c in first slot 50 a until trigger 4 a is pressured to pivot on trigger pivot 28 subsequently disengaging trigger insert 4 c from first slot 50 a thereby allowing securing member 52 to slide to the open condition. The closed condition of securing member 52 may also be achieved from an open condition, if so biased by main energy storage device 22 , through pressure on trigger 4 a, the subsequent pivot of trigger 4 a on trigger pivot 28 and the disengagement of trigger insert 4 c from second slot 50 b.
[0054] The other securing member 52 condition is the open condition and may be used as boat 12 is being released from boat trailer 38 and before being retrieved again. The open securing member 52 condition may be the result of both biasing mechanism handle 24 being in second biasing mechanism slot 64 b biasing main energy storage device 22 to pressure securing member 52 toward the open condition and securing eye 16 contacting trigger 4 a thereby moving trigger insert 4 c to be disengaged from second slot 52 in securing member 52 . Said securing member 52 will remain in the open condition even if biasing mechanism securing member 20 pressures securing member 52 toward the closed condition by means of main energy storage device 22 unless and until the trigger 4 a is tripped with sufficient force. Said securing member 52 may move to the closed condition only after each of the following is accomplished: biasing mechanism handle 24 is within first biasing mechanism slot 64 a biasing mechanism securing member 20 to pressure main energy storage device 22 subsequently pressuring securing member 52 toward the closed condition and trigger 4 a is tripped disengaging trigger insert 4 c from second slot 50 b.
[0055] There are two preferred release trigger 4 a conditions. The release trigger 4 a may be in the engaged condition due to force from secondary energy storage device 26 unless sufficient force is applied, which may be by securing eye 16 or manually, to compress secondary energy storage device 26 thereby disengaging trigger insert 4 c from first slot 50 a or second slot 50 b. When trigger 4 a is engaged, securing member 52 may be prevented from moving regardless of the condition of the biasing mechanism handle 24 or said securing member 52 . Upon the tripping of trigger 4 a, securing member 52 may achieve the condition for which it is currently biased, from either open to closed or vice versa, in relation to the disposition of the biasing mechanism handle 24 and biasing mechanism securing member 20 . For example, if biasing mechanism handle 24 is in second biasing mechanism slot 64 b and securing member 52 is in the closed condition, upon the tripping of the release trigger 4 a, securing member 52 may retract to the release condition. This may allow the release of securing eye 16 . In another example, if biasing mechanism handle 24 is in first biasing mechanism slot 64 a and securing member 52 is in the open condition, upon the tripping of trigger 4 a , securing member 52 may move into the closed condition. This may secure securing eye 16 in a secured condition in securing slot 54 . In other examples, should securing member 52 be in the closed condition and the biasing mechanism handle 24 be in the lock condition in first biasing mechanism slot 64 a, or securing member 52 be in the open condition and biasing mechanism handle 24 be in the release condition in second biasing mechanism slot 64 b, then no movement of securing member 52 may result should trigger 4 a be tripped. This allows the boat 12 to be trailered without the concern that securing member 52 will retract inadvertently, or conversely, allows securing member 52 to remain in the release condition if desired.
[0056] There are four preferred main energy storage device 22 conditions. The first is a fully compressed condition and may be the result of said main energy storage device 22 being compressed between securing member 52 in the release condition and biasing mechanism securing member 20 in the lock condition.
[0057] The second main energy storage device 22 condition is a slightly compressed condition and may be the result of securing member 52 being in the lock condition in securing member slot 62 and biasing mechanism securing member 20 being in the lock condition. This may be the most common condition of biasing mechanism 18 and securing member 52 and may be used whenever the boat 12 is loaded on the boat trailer 38 other than during periods of the launch or retrieval process of boat 12 .
[0058] The third main energy storage device 22 condition is fully stretched and may be achieved by securing member 52 being in the lock condition in securing member slot 62 and the biasing mechanism securing member 20 being is in the release condition exemplified by biasing mechanism handle 24 being in second biasing mechanism slot 64 b. This configuration may be used during periods of the boat 12 launching process from the boat trailer 38 . In said condition, the main energy storage device 22 may be fully stretched until force is applied to the trigger 4 a thereby retracting trigger insert 4 c away from first slot 50 a allowing securing member 52 to move to the release condition.
[0059] The fourth main energy storage device 22 condition is slightly stretched and may be achieved when securing member 52 is in the release condition and the biasing mechanism handle 24 is in the release condition in second biasing mechanism slot 64 b . This configuration may be evident immediately after the boat has been launched and while boat 12 is not present on trailer 38 .
[0060] The present invention in its entirety does not preclude the boater from using the traditional winch 30 , strap 32 and hook assembly in the event that the boat 12 is inoperable and must be winched into place on the trailer 38 ; in which case the automatic securing mechanism can still be used advantageously to simplify the winching process. Furthermore, it is recommended that the winch 30 , strap 32 and hook assembly be used in conjunction with this automatic securing and release system as a secondary safety measure.
[0061] An example of an embodiment of the present invention incorporates a V-shaped bow guide that may be built into the housing 1 . Said bow guide is designed to receive the bow of boat 12 and align the boat 12 centerline and securing eye 16 with V-shaped receiver 14 and securing eye slot 54 . In so doing, trigger 4 a may be accessible to contact with securing eye 16 .
[0062] Another example of an embodiment of the present invention is a simple but effective attachment feature that may allow for easy installation on a modern boat trailer 38 . A mounting bracket 6 is molded into the lower portion of housing 1 that is designed to be secured to first winch arm extension 8 a and second winch arm extension 8 b which may previously secure a roller apparatus found a modern boat trailer 38 . Installation of the present invention on said trailer may be accomplished using a single bolt (mounting bolt 66 ). The earlier referenced one piece construction of the invention and the accompanying mounting bracket 6 may ensure that the invention in its entirety will remain in the optimal position to receive the boat 12 bow section and align said boat's securing eye 16 with the invention's V-shaped receiver 14 . Said optimal position may initially, absent contact from the boat, be slightly downward relative to the angle of the boat's centerline vertical angle. However, upon and after contact of the boat 12 , first bow guide 2 a and second bow guide 2 b, the bow guide centerline 56 may remain vertically and horizontally flush against the boat 12 centerline by pivoting longitudinally on the mounting bolt 66 as said boat 12 advances on boat trailer 38 . Said pivoting allows the invention to adapt to the various vertical steepnesses of modern boats as well as facilitating proper alignment, both vertically and horizontally, of the invention against the varying vertical steepness of a numerous boats as well as a particular boat 12 during the loading and unloading process. Said positioning also facilitates the alignment of boat 12 on the boat trailer 38 , aligns the boat 12 securing eye 16 with the V-shaped receiver 14 as well as ensuring that the trigger 4 a mechanism will not be tripped on the boat 12 bow rather than on securing eye 16 .
[0063] Critical elements make the present invention novel. The specific mechanism employed is unique. The use of a biasing mechanism that facilitates both securing and releasing the boat 12 securing eye 16 is unique. The one piece design that incorporates the securing and releasing mechanism, a novel bow guide design which properly aligns securing eye 16 with the securing and releasing mechanism, a simple mechanism for attaching the invention to boat trailer 38 and the ability to continue to use the traditional winch 30 , strap 32 and hook apparatus as a secondary safety measure each make the invention novel.
[0064] Now although the systems described have been discussed in relation to a boat, those systems may be adapted to other watercraft types with minor modification, for example personal watercraft such as jet skis. Described systems might also be adapted for use with land vehicles, for example all terrain vehicles that may be trailered. The scope of the above described systems should therefore be interpreted broadly rather than restrictively.
[0065] While various systems incorporating a trailer mountable receiver and release mechanism have been described and illustrated in conjunction with a number of specific settings, a professional will appreciate that variations and modifications may be made without departing from the principles herein described, illustrated and claimed. The present invention, as defined by the appended claims, may be embodied in other specific forms without departing from its spirit or essential characteristics. The configurations described herein are to be considered in all respects to be illustrative, and not restrictive. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. | The invention relates to a mechanism that attaches and releases a boat or personal watercraft or the like to a trailer or lift or the like and includes a trigger which can move between a secured and released condition by means of contact with the boat or manually and which is biased by an energy storage device. Said trigger in turn may restrict or release a securing member or members which releases or secures a boat's eyehook. Said securing member may be biased by a primary energy device that may be moved to a locked or released condition as desired to attach the boat to, or release the boat from, the trailer. |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a National Phase Application of PCT International Application No. PCT/EP2013/074351, International Filing Date Nov. 21, 2013, claiming priority of German Patent Application No. 10 2012 025 002.9, filed Dec. 20, 2012, each of which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
The invention relates to a method for diagnosing an exhaust-gas catalytic converter arranged in the exhaust-gas system of the internal combustion engine for the catalytic conversion of at least one exhaust-gas component of an internal combustion engine; the invention also relates to a diagnostic device that is configured to carry out said method, and to a motor vehicle having such a diagnostic device. In a special embodiment, the exhaust-gas catalytic converter is a catalytic converter that functions according to the principle of selective catalytic reduction for purposes of reducing nitrogen oxide NO x .
BACKGROUND OF THE INVENTION
Internal combustion engines that are operated either constantly or at times with a lean air-fuel mixture produce nitrogen oxides NO x (mainly NO 2 and NO), which require NO x -reducing measures. Exhaust-gas recirculation constitutes an engine-related measure aimed at reducing NO x raw emissions in the exhaust gas, and this is a process in which part of the exhaust gas of the internal combustion engine is recirculated into its combustion air, as a result of which the combustion temperatures are lowered and consequently the formation of NO x (NO x raw emission) is reduced. As a rule, however, exhaust-gas recirculation is not sufficient to comply with statutory NO x limit values, which is why there is an additional need for an active exhaust-gas after-treatment that lowers the NO x end emission by catalytically reducing NO x to form nitrogen N 2 . A known NO x exhaust-gas after-treatment involves the use of NO x -storage catalytic converters which, during lean operation (with λ>1), store nitrogen oxides in the form of nitrates and, at short intervals with a rich exhaust-gas atmosphere (λ<1), desorb the stored nitrogen oxides and reduce it to nitrogen N 2 in the presence of the reductants present in the rich exhaust gas.
Another approach to convert nitrogen oxides in the exhaust gases of lean-burning internal combustion engines is the use of catalyst systems that operate according to the principle of selective catalytic reduction (SCR). These systems comprise at least one SCR catalytic converter that, in the presence of a reductant metered into the exhaust gas—normally ammonia NH 3 —selectively convert the nitrogen oxides of the exhaust gas into nitrogen and water. In this context, the ammonia can be metered into the exhaust-gas stream from an aqueous solution of ammonia or from a precursor compound, for instance, urea in the form of an aqueous solution or solid pellets, obtained through the modality of thermolysis and hydrolysis. A more recent approach for ammonia storage in a motor vehicle utilizes the NH 3 -storage materials that reversibly bind the ammonia as a function of the temperature. In this context, metal-ammine storage materials are well known such as, for example, MgCl 2 , CaCl 2 and SrCl 2 , which store ammonia in the form of a complex compound so that it is then present, for example, as MgCl 2 (NH 3 ) x , CaCl 2 (NH 3 ) x or SrCl 2 (NH 3 ) x . The ammonia can once again be released from these compounds by feeding in heat.
It likewise a known procedure to continuously check the proper functioning of exhaust-gas catalytic converters comprising SCR catalytic converters or NO x -storage catalytic converters by means of on-board diagnostics (OBD). Towards this end, the signal of an exhaust-gas sensor (NO x sensor) located downstream from the catalytic converter is normally employed for the appertaining exhaust-gas component in order to measure the concentration of this exhaust-gas component downstream from the catalytic converter. Furthermore, the concentration of the exhaust-gas component is determined upstream from the catalytic converter, that is to say, the raw emission of the engine. This can be done by measuring the concentration by means of another exhaust-gas sensor installed upstream from the catalytic converter. However, the raw emission is more often ascertained by means of modeling using stored characteristic maps that depict the concentration of the component as a function of the momentary operating point of the internal combustion engine. The efficiency η of the exhaust-gas catalytic converter in terms of the conversion of the component can then be obtained, for example, from the equation below, wherein c_end is the concentration (or contents) of the exhaust-gas component measured downstream from the catalytic converter and c_raw stands for the raw emission of the internal combustion engine regarding this component:
η
=
1
-
c_end
c_raw
The efficiency η can thus assume values from 0 to 1. An ideally functioning catalytic converter that brings about a complete catalytic conversion (c_end=0) thus exhibits an efficiency η of 1, whereas η=0 (c_end=c_raw) in the case of a completely inactive catalytic converter.
German patent application DE 10 2010 042 442 A1 describes an exhaust-gas system with an SCR catalytic converter as well as with a low-pressure exhaust-gas recirculation system by means of which an exhaust-gas stream is withdrawn downstream from a turbine of an exhaust-gas turbocharger (on the low-pressure side) and downstream from the SCR catalytic converter, while the combustion air of the internal combustion engine is fed in upstream from a compressor of the exhaust-gas turbocharger (on the low-pressure side). In the exhaust-gas recirculation line, there is a NO x sensor that measures the concentration of nitrogen oxides in order to regulate the internal combustion engine on the basis of the NO x concentration thus ascertained, especially the exhaust-gas recirculation (EGR) rate or the air-fuel ratio. The exhaust-gas recirculation line is also connected to the air line of the internal combustion engine via a bypass that opens up into the air line downstream from the compressor, in other words, on its high-pressure side. In order to determine an offset of the NO x sensor so that it can be calibrated, the bypass is opened, which brings about a reversal in the direction of flow in the exhaust-gas recirculation line, so that the NO x sensor is charged with fresh air. A diagnose of the SCR catalytic converter is not described here.
SUMMARY OF THE INVENTION
The invention is based on the objective of putting forward a method for the diagnosis of an exhaust-gas catalytic converter in terms of its conversion rate for an exhaust-gas component, said method standing out for its improved precision. The method should lend itself, for example, for the diagnosis of an SCR catalytic converter. The invention likewise puts forward a diagnostic device that is suitable to carry out the method, and a corresponding motor vehicle.
These objectives are achieved by means of a method for the diagnosis of an exhaust-gas catalytic converter arranged in the exhaust-gas system of an internal combustion engine as well as by a motor vehicle having the features of the independent claims.
Before this backdrop, the invention relates to an internal combustion engine having an exhaust-gas recirculation system with which a partial stream of the exhaust gas is withdrawn downstream from the exhaust-gas catalytic converter and fed into the combustion air of the internal combustion engine. The method according to the invention comprises the following features:
determining the momentary raw emission of the internal combustion engine in terms of the exhaust-gas component; measuring the momentary concentration of the exhaust-gas component in the exhaust gas upstream from the exhaust-gas catalytic converter; and determining a diagnostic value of the exhaust-gas catalytic converter in terms of the conversion of the exhaust-gas component as a function of the modeled raw emission of the internal combustion engine and of the concentration measured in the exhaust gas.
Therefore, unlike with conventional methods, the momentary concentration of the exhaust-gas component here is not determined downstream from the exhaust-gas catalytic converter that is to be diagnosed, but rather, upstream from it. In this context, the invention makes use of the fact that the exhaust gas measured upstream from the exhaust-gas catalytic converter is also influenced by the activity of the exhaust-gas catalytic converter due to the exhaust-gas recirculation. The lower the conversion rate, the higher the concentration of the exhaust-gas component at the measuring site upstream from the exhaust-gas catalytic converter. Due to the relatively close proximity to the engine, the exhaust-gas sensor needed for measuring the exhaust-gas component achieves its operational readiness much sooner after a cold engine start-up and is thus activated sooner than a sensor located downstream from the catalytic converter; as a result, the frequency with which the diagnosis of the exhaust-gas catalytic converter is carried out is considerably increased in comparison to conventional methods. This translates into greater precision and reliability of the catalytic converter diagnosis. Moreover, the procedure according to the invention can also recognize a defective catalyst that only constitutes part of a catalytic converter system.
The measurement of the concentration of the exhaust-gas component is preferably done in a place of the exhaust-gas system that is close to the engine. This refers to any place that is upstream from an underbody place in the exhaust-gas system. In particular, the measuring point for the concentration of the exhaust-gas component is located at the maximum at a distance of 120 cm from a cylinder outlet of the internal combustion engine, preferably 100 cm at the maximum, and especially preferred 80 cm at the maximum. Since the sensor needed for the measurement is arranged close to the engine, the operational readiness of the sensor is reached much sooner after a cold start of the engine, thus allowing the catalytic converter diagnosis to be carried out very frequently.
In a preferred embodiment of the method, the efficiency of the exhaust-gas catalytic converter is determined as a diagnostic value as a function of the ratio of the modeled raw emission to the measured concentration. Especially preferably, the efficiency η is ascertained according to the equation below, whereby NO x— meas stands for the concentration of the exhaust-gas component measured upstream from the exhaust-gas catalytic converter, while NO x— raw stands for the raw emission of the exhaust-gas component, and α_EGR stands for the exhaust-gas recirculation rate, in other words, the portion of recirculated exhaust gas in the combustion air of the internal combustion engine:
η
=
1
-
α_
EGR
-
1
(
NO
x–
meas
-
NO
x–
raw
)
NO
x–
raw
This equation takes into consideration the fact that the sensor arranged upstream from the exhaust-gas catalytic converter measures the sum of the engine raw emission in terms of the exhaust-gas component as well as the portion that has not been converted by the exhaust-gas catalytic converter and recirculated via the EGR.
According to an advantageous embodiment, the diagnostic value determined for the exhaust-gas catalytic converter, for instance, the efficiency η, is compared to a corresponding target value that is determined particularly for a new and completely intact exhaust-gas catalytic converter. If, in this process, a predetermined minimum deviation from the target value has been exceeded, a fault in the exhaust-gas catalytic converter is ascertained and this is output. As an alternative, the diagnostic value is compared to a corresponding threshold value and, if the threshold value has been exceeded (either upwards or downwards, depending on the type of threshold value), a fault in the exhaust-gas catalytic converter is ascertained and this is output. The fault is preferably output to an engine control unit of the internal combustion engine and/or as a visual and/or acoustic fault message to the driver. In a preferred embodiment, the threshold value and/or the target value is predetermined as a function of an operating point of the internal combustion engine, especially an engine load or engine speed. A stored characteristic map can be employed for this purpose.
The momentary raw emission of the internal combustion engine is preferably likewise modeled as a function of the momentary operating point of the internal combustion engine, whereby here, too, preferably a characteristic map can be employed. The modeled raw emission of the internal combustion engine as a function of the operating point, particularly the engine load and engine speed, constitutes such a characteristic map.
The invention also relates to a diagnostic device for diagnosing an exhaust-gas catalytic converter arranged in the exhaust-gas system of an internal combustion engine for the catalytic conversion of at least one exhaust-gas component of the internal combustion engine, whereby the diagnostic device is configured to carry out the method according to the invention. In particular, the diagnostic device comprises a computer-readable algorithm for carrying out the method as well as optionally needed characteristic lines and characteristic maps in computer-readable stored form. The diagnostic device can be an autonomous device with its own signal lines, or else it can be integrated into an engine control unit.
The invention also relates to a motor vehicle with an internal combustion engine, an exhaust-gas system connected thereto, an exhaust-gas catalytic converter installed in the exhaust-gas system for the catalytic conversion of at least one exhaust-gas component of the internal combustion engine, an exhaust-gas sensor located upstream from the exhaust-gas catalytic converter for purposes of measuring the momentary concentration of the exhaust-gas component in the exhaust gas, an exhaust-gas recirculation system for withdrawing a partial stream of the exhaust gas downstream from the exhaust-gas catalytic converter and for feeding the withdrawn partial stream of exhaust gas into the combustion air of the internal combustion engine as well as a diagnostic device configured to carry out the method.
Preferably, the exhaust-gas catalytic converter that is to be diagnosed is a catalytic converter for the reduction of nitrogen oxides, especially a catalytic converter that functions according to the principle of selective catalytic reduction (SCR). Accordingly, the exhaust-gas component comprises nitrogen oxides NO x , whereby the exhaust-gas sensor is a sensor configured to measure nitrogen oxides, especially a NO x sensor. As an alternative, however, the NO x measurement can also make use of lambda sensors which have the appropriate cross-sensitivity and which issue an appropriate output signal that correlates with the NO x concentration.
The reductant that is metered in is preferably ammonia NH 3 or a precursor compound thereof, whereby especially urea is an option here. The urea can be used in the form of solid urea pellets but preferably in the form of especially an aqueous solution of urea. The metered-in urea reacts via the modality of thermolysis and hydrolysis, releasing NH 3 in this process. Within the scope of the invention, the reductant ammonia can also fundamentally be stored by means of NH 3 -storage materials which reversibly bind or release ammonia as a function of the temperature. Appropriate metal-ammine storage materials were already elaborated upon above.
The use of the method according to the invention for other exhaust-gas catalytic converters such as, for instance, NO x -storage catalytic converter or oxidation catalytic converters, is likewise possible.
According to another preferred embodiment of the invention, the exhaust-gas after-treatment device also has an oxidation catalytic converter. This catalytic converter is preferably located upstream from the SCR catalytic converter that is to be diagnosed. In this manner, it is achieved that the ratio of NO 2 to NO of the exhaust gas is increased, resulting in an improved NO x conversion rate of the SCR catalytic converter located downstream. If, in addition, the oxidation catalytic converter is situated downstream from the metered-in reductant, the result is an improved homogenization of the reductant metered into the exhaust gas before it enters the SCR catalytic converter.
The internal combustion engine is an internal combustion engine that is lean-running constantly or at least at times, especially a diesel engine. Fundamentally speaking, the exhaust-gas after-treatment device according to the invention, however, can also be advantageously used for Otto engines that are lean-running at times, especially Otto engines that operate with direct gasoline injection.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explained in greater detail below on the basis of embodiments making reference to the accompanying drawings. The following is shown:
FIG. 1 a schematic view of an exhaust-gas system according to an advantageous embodiment of the invention; and
FIG. 2 a flow chart for carrying out a diagnosis of an SCR catalytic converter according to an advantageous embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The invention will be presented below on the basis of an example of an SCR catalytic converter. However, it goes without saying that the invention can also be employed for other exhaust-gas catalytic converters.
FIG. 1 shows a drawing of a motor vehicle which is designated in its entirety by the reference numeral 10 and which is driven by an internal combustion engine 12 that is lean-running, at least at times, especially by a diesel engine that serves as the source of traction. The internal combustion engine 12 here has, for instance, four cylinders, whereby any number of cylinders diverging from this is likewise possible.
The internal combustion engine 12 is supplied with combustion air via an air line 14 and via an air manifold 16 that conveys the drawn-in air to the cylinders. The combustion air drawn in from the ambient air is cleaned of particulate constituents by means of an air filter 18 .
The motor vehicle 10 also has an exhaust-gas system which is designated in its entirety by the reference numeral 20 and which serves for the catalytic after-treatment of exhaust gas from the internal combustion engine 12 . The exhaust-gas system 20 comprises an exhaust-gas manifold 22 that connects the individual cylinder outlets of the internal combustion engine 12 to an exhaust-gas conduit 24 . The exhaust-gas conduit 24 has a section (shown here) close to the engine as well as an underbody section (not shown here) that ends in the exhaust pipe. The exhaust-gas conduit 24 houses various components for the exhaust-gas after-treatment.
In the example shown, the exhaust gas first reaches an oxidation catalytic converter 26 . This catalytic converter has a substrate that is coated with a catalytic coating that catalyzes the oxidation of exhaust-gas components. In particular, it is well-suited for converting unburned hydrocarbons HC and carbon monoxide CO into CO 2 and H 2 O. Moreover, the catalytic coating of the oxidation catalytic converter 26 is configured to oxidize No and N 2 O to form NO 2 in order to increase the ratio of NO 2 to NO. The catalytic coating of the oxidation catalytic converter 26 contains as the catalytic component particularly at least one element from the group of platinum metals Pt, Pd, Rh, Ru, Os or Ir, or else a combination thereof, especially Pt and/or Pd. The catalytic coating of the oxidation catalytic converter 26 also contains a washcoat comprising a porous ceramic matrix having a large specific surface area, for example, on the basis of zeolite, which is doped with the catalytic component. The substrate of the oxidation catalytic converter 26 can be a metallic substrate or a ceramic monolith, especially a honeycomb-like structure having a plurality of continuous, parallel flow channels. Suitable ceramic materials include aluminum oxide, cordierite, mullite and silicon carbide. Suitable material substrates are made out of stainless steel or iron-chromium alloys.
Downstream from the oxidation catalytic converter 26 , there is another exhaust-gas catalytic converter, here an SCR catalytic converter 28 in the exhaust-gas conduit 24 . The SCR catalytic converter 28 , like the oxidation catalytic converter 26 , comprises a catalytic substrate on a metallic or ceramic basis, preferably on a ceramic basis. Suitable ceramic or metallic materials correspond to those mentioned in conjunction with the oxidation catalytic converter. The inner walls of the parallel and continuous flow channels of the substrate are coated with an SCR catalytic coating that brings about the reduction of nitrogen oxides to form nitrogen under selective consumption of a reductant. The coating, in turn, comprises a washcoat consisting of a porous ceramic matrix having a large specific surface area (e.g. a zeolite on an aluminum silicate basis), with catalytic substances distributed thereupon. Suitable SCR catalytic substances encompass especially non-noble metals such as Fe, Cu, Va, Cr, Mo, W as well as combinations thereof. These substances are deposited onto the zeolite and/or the zeolite metals are partially replaced by the corresponding non-noble metals through the modality of ion exchange. The SCR catalytic converter 28 is preferably arranged in a place that is close to the engine. In particular, the distance (path of the exhaust gas) between the cylinder outlet and an inlet face of the SCR catalytic converter 28 amounts to 120 cm at the maximum.
The exhaust-gas system 20 also has a reductant metering unit 30 with which the reductant or a precursor compound thereof is metered into the exhaust gas. For instance, the reductant is introduced into the exhaust-gas stream by means of a nozzle located upstream from the SCR catalytic converter 28 . The reductant can typically be ammonia NH 3 that is metered in in the form of a precursor compound, especially in the form of urea. Preferably, the urea in the form of an aqueous solution is conveyed and metered in from a reservoir (not shown here). In a mixer 32 installed downstream from the metering unit 30 , the urea is mixed with the hot exhaust gas and decomposed to form NH 3 and CO 2 through the modality of thermolysis and hydrolysis. The NH 3 is stored in the coating of the SCR catalytic converter 28 , where it is used for the reduction of nitrogen oxides. The reductant is usually metered in via the metering unit 30 by means of a control system (not shown here) which regulates the unit 30 as a function of a given operating point of the engine 12 , especially as a function of the momentary NO x concentration in the exhaust gas.
The vehicle 10 also comprises an exhaust-gas turbocharger that has a turbine 34 arranged in the exhaust-gas conduit 24 , said turbine being joined, for example, by means of a shaft to a compressor 36 situated in the air line 14 . The turbine 34 withdraws kinetic energy from the exhaust gas in order to drive the compressor 36 and in order to compress the drawn-in combustion air. Normally, downstream from the compressor 36 , there is an intercooler (not shown here) by means of which heat that was generated by the compression is withdrawn from the combustion air.
The motor vehicle 10 also has a low-pressure exhaust-gas recirculation system (LP-EGR) 38 . It has an exhaust-gas recirculation line 40 that, on the low-pressure side of the turbine 34 downstream from the SCR catalytic converter 28 , withdraws a partial stream of the exhaust gas from the exhaust-gas conduit 24 and feeds it into the air line 14 on the low-pressure side of the compressor 36 . An EGR cooler 42 situated in the EGR line 40 cools the hot, recirculated exhaust gas. The EGR rate, that is to say, the recirculated portion of exhaust gas in the combustion air of the internal combustion engine 12 , is regulated by means of an EGR valve 44 likewise situated in the EGR line 40 . Normally, the EGR valve 44 is regulated as a function of a given operating point of the internal combustion engine 12 , whereby the valve 44 can be continuously varied between a completely closed position (EGR rates of zero, complete deactivation of the EGR) and a completely open position.
Like all exhaust-gas catalytic converters, the SCR catalytic converter 28 is also subject to an age-related worsening of its catalytic activity. For this reason, there is a need for an ongoing diagnosis of the SCR catalytic converter 28 in order to detect an unacceptable weakening of its catalytic activity. According to the invention, the SCR catalytic converter 28 is diagnosed by means of a NO x sensor 46 situated upstream from it. Preferably, the sensor 46 is installed upstream from the reductant metering unit 30 and especially preferably upstream from the oxidation catalytic converter 26 . Since the NO x sensor 46 is arranged very close to the engine 12 , it can quickly reach operational readiness after a cold start of the engine 12 . An output signal NO x— meas of the NO x sensor 46 is entered as an input quantity into a diagnostic device 48 . Moreover, the diagnostic device 48 receives information about the momentary EGR rate α_EGR and the momentary operating point of the internal combustion engine 12 , especially in the form of the engine load L and the engine speed n. As a function of these and, if applicable, other quantities, the diagnostics device performs a diagnosis of the SCR catalytic converter 28 by means of the method according to the invention, as will be elaborated upon in greater detail below with reference to FIG. 2 .
By way of an example, FIG. 2 shows the sequence of the method according to the invention for the diagnosis of an SCR catalytic converter, in the form of a flow chart that is executed at regular intervals by the diagnostic device 48 .
The method is initialized in step S 1 and then proceeds to the query S 2 , which checks whether the NO x sensor 46 is active. If this is not the case, for instance, after a cold start, the diagnosis cannot be carried out and the method returns to the starting point. If, on the other hand, the NO x sensor 46 is active, that is to say, if its output signal has been activated, the method proceeds to a second query S 3 , which checks whether the exhaust-gas recirculation system is active, that is to say, whether the EGR valve 44 is at least partially open. If the exhaust-gas recirculation system is not active, the diagnosis cannot be carried out and the method returns to its starting point. If, in contrast, the exhaust-gas recirculation system is active, that is to say, the answer to the query in S 3 is “yes”, then the diagnosis of the SCR catalytic converter 28 is carried out.
For this purpose, in step S 4 , the diagnostic device 48 reads in the output signal of the NO x sensor 46 and, as a function of the sensor signal, determines the momentary concentration of nitrogen oxides NO x— meas in the exhaust gas. Typically, for this purpose, a stored sensor characteristic line is employed which represents the NO x concentration as a function of the sensor signal, for instance, a sensor voltage. It goes without saying that the term “concentration” refers to any information about the content of the exhaust-gas component in the exhaust gas, irrespective of the unit used.
Subsequently, in step S 5 , the diagnostic device 48 reads in several input quantities. In particular, these include the engine load L, which is determined, for instance, on the basis of the gas pedal actuation by the driver, the engine speed n as well as the momentary EGR rate α_EGR. The momentary NO x raw emission NO x— raw is modeled as a function of the engine load L and of the engine speed n. This can either be calculated by means of a mathematical model or else it can make use of stored characteristic lines or characteristic maps. In particular, a characteristic map is used that depicts the NO x raw emission NO x— raw as a function of the engine load L and of the engine speed n. The determination of such characteristic maps, for example, on an engine test bench, is a known procedure and will not be elaborated upon here.
Subsequently, in step S 7 , a diagnostic value is determined for the SCR catalytic converter 28 in terms of its conversion of NO x . In particular, an efficiency η is calculated here, for which purpose the modeled raw emission NO x— raw is related to the measured NO x concentration NO x— meas. For example, the efficiency η can be determined according to the following equation:
η
=
1
-
α
–
EGR
-
1
(
NO
x–
meas
-
NO
x–
raw
)
NO
x–
raw
Subsequently, in step S 8 , the determined efficiency η is compared to an efficiency threshold value η_sw. Preferably, the threshold value η_sw is predetermined by the diagnostic device 48 as a function of the engine operating point (L,n). If the momentarily determined efficiency is equal to or greater than η_sw, the answer to the query is “no”, meaning that the SCR catalytic converter 28 is intact, and the method returns to the starting point. Optionally, the momentary diagnostic value η can be stored for documentation purposes. However, if the answer to the query in step S 8 is “yes”, that is to say, if the efficiency η has fallen below the threshold value then, in step S 9 , a fault in the catalytic converter 28 is determined. The fault can be output as a visual and/or acoustic signal to the driver of the vehicle, and/or it can be relayed to the engine control unit, from where it can be read out at the time of the next servicing.
LIST OF REFERENCE NUMERALS
10 motor vehicle
12 internal combustion engine
14 air line
16 air manifold
18 air filter
20 exhaust-gas system
22 exhaust-gas manifold
24 exhaust-gas conduit
26 oxidation catalytic converter
28 exhaust-gas catalytic converter/SCR catalytic converter
30 reductant metering unit
32 mixer
34 turbine
36 compressor
38 low-pressure exhaust-gas recirculation system
40 exhaust-gas recirculation line
42 EGR cooler
44 EGR valve
46 NO x sensor
48 diagnostic device
α_EGR EGR rate (portion of exhaust gas in the combustion air)
L engine load
n engine speed
NO x— meas measured concentration of the exhaust-gas component in the exhaust gas upstream from the exhaust-gas catalytic converter
NO x— raw modeled raw emission of the exhaust-gas component in the internal combustion engine | A method for diagnosing an exhaust-gas catalytic converter ( 28) arranged in an exhaust-gas system ( 20) of an internal combustion engine ( 12) for the catalytic conversion of at least one exhaust-gas component from the internal combustion engine ( 12), which has an exhaust-gas recirculation means with which a partial stream of the exhaust gas can be drawn off downstream of the catalytic converter ( 14) and fed into the combustion air of the internal combustion engine ( 12), involves determining the current raw emission (NO x-- raw) of the internal combustion engine ( 12) in of the exhaust-gas component; measuring the current concentration of the exhaust-gas component (NO x-- meas) in the exhaust gas upstream of the catalytic converter ( 28); and determining a diagnostic value for the catalytic converter ( 28) in terms of the conversion of the exhaust-gas component as a function of the modelled raw emission (NO x-- raw) from the internal combustion engine ( 12) and the measured concentration of the exhaust-gas component (NO x-- meas). The invention further relates to a diagnostic device configured to perform the method and a motor vehicle having such a device. |
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 61/063,154 entitled “Composite Phosphors Based on Coating Porous Substrates,” filed Jan. 30, 2008, and U.S. Provisional Application Ser. No. 61/063,153 entitled “Polymer-Assisted Deposition of Conformal Films on Porous Materials,” both hereby incorporated by reference.
STATEMENT REGARDING FEDERAL RIGHTS
[0002] This invention was made with government support under Contract No. DE-AC52-06NA25396 awarded by the U.S. Department of Energy. The government has certain rights in the invention.
FIELD OF THE INVENTION
[0003] The present new light-emitting devices that result from conformal films on porous materials, in particular luminescent metal oxide films, and more particularly these luminescent metal oxide films deposited on porous alumina and silica structures resulting in composite phosphors or scintillators.
BACKGROUND OF THE INVENTION
[0004] Phosphors find applications in many Light Emitting Devices (“LED”). Thin films of phosphors are used in many imaging and LED applications from radiation detection to solid state lighting. The key properties of phosphors include quantum yield, stability and lifetime. In particular for LEDs the efficiency of conversion of high energy blue excitation light to the white light is a key factor for the overall LED efficiency. Phosphors are an integral part of any LED, and unfortunately contribute significantly to efficiency losses. The loss mechanisms include fundamental losses innate to the phosphor conversion material (nonradiative decay paths that lead to reduced quantum yields) and reduced extraction efficiency. The reductions in extraction efficiency include radial emission from the phosphor and wave guiding at interfaces. Phosphors are often applied in an epoxy layer over the high energy emitting GaN light source. If smooth layers are applied, effective wave guiding can occur that channels light to the sides of the device. Efforts have been made to reduce this effect through surface roughening but extraction efficiencies remain at or near 60% in the best cases. Typically phosphors are only available as powders or as thin film coatings.
[0005] One of the major obstacles in the development of high efficiency systems is loss due to wave guiding when thin film phosphors are used. Thin films help to minimize losses from self absorption, but the planar interface between the phosphor layer and other layers in the device lead to interfaces with different refractive indexes. At these interfaces all light from the phosphor that hits the interface at an angle greater than the critical angle as defined by Snell's Law is effectively reflected at the surface and wave guided to the edges of the film. One way to avoid this problem is to place the phosphor as a thin film on a three dimensional structure with vertical structures that allow the light to propagate in the desired direction. As the surface area of the 3-dimensional structure increases, more phosphor can be excited resulting in higher light yield. Porous structures offer great potential, but they are very difficult to coat. Two potential substrates include porous anodiscs that consist of a honeycomb structure with straight channels having pore diameters from 20 to 200 nm, and a second structure is posed on porous inverse opal structures having well defined connected cavities that can be readily controlled to the hundreds of nanometers, up to 500 nm. Both of these structures have high surface areas but the nanometer scale porosity with openings or cavities less than 900 nm make them very difficult to coat by traditional line-of-site techniques. More complex structures include mesoporous silica, such as Mobile Crystalline Materials (“MCMs”) which possess to some degree of ordered arrays of non intersecting hexagonal channels with the pore diameter of these materials within mesoporous range between 1 to 20 nm. Porous structures of this invention, therefore include pores in a range of from 1 to 500 nm.
[0006] Over the past 10 years, photonic crystal (“PC”) structures have emerged as perhaps the ultimate platform for microdevices that can manipulate light in all three dimensions. These artificial microstructures consist of a periodic repetition of dielectric elements, which creates forbidden and allowed energy bands for photons. PCs represent a major new frontier in optoelectronics due to their ability to coherently manipulate light. This manipulation is essential for enabling new concepts such as producing negative indices of refraction, tailoring the photonic density of states, controlling spontaneous emission rates, and modifying and controlling black-body radiation. It has been predicted [Shanhui Fan, et al., Phys. Rev. Lett. 78, 3294 (1997)] that a weakly penetrating etched photonic lattice on the surface of an LED can suppress all lateral modes, causing the light to be emitted primarily in the vertical direction.
[0007] Photonic crystal (“PC”) structures have emerged as perhaps the ultimate platform for micro-devices that can manipulate light in all three dimensions. PCs represent a major new frontier for a diverse set of properties including their ability to coherently manipulate light. It has been predicted that a weakly penetrating etched photonic lattice on the surface of an LED can suppress all lateral modes, causing the light to be emitted primarily in the vertical direction. PCs have been restricted to a subset of materials that can be formed in the sol-gel processing. It is not possible to make PCs from just any material, which limits their potential properties. Coating is one way to add functionality, but traditional techniques Pulsed laser deposition (“PLD”) and Chemical Vapor Deposition (“CVD”) cannot coat the complex porous structures. Sol-gel can penetrate the pores but does not result in conformal coatings since metal oxide oligomers form in the bulk solution. The primary technique used for effective coating of 3-D materials such as inverse opal structures is Atomic Layer Deposition (“ALD”). ALD is limited in that thicker coatings require many steps and only single component coatings can be readily applied. Polymer-Assisted Deposition (“PAD”) can deposit conformal coatings of complex metal oxides on nano-structured 3-D supports. This ability to form conformal coatings has led to the formation of completely new compositions of coated mesoporous silicon (silica) that emit light. Light emission from mesoporous silicon has been reported previously but never from conformally-coated materials.
[0008] A scintillator is a material that is transparent in the scintillation or emission wavelength range and that responds to incident radiation by emitting a light pulse. From such materials, generally single crystals, it is possible to manufacture detectors in which the light emitted by the crystal that the detector comprises is coupled to a light-detection means and produces an electrical signal proportional to the number of light pulses received and to their intensity. Such detectors are used especially in industry for thickness or weight measurements and in the fields of nuclear medicine, physics, chemistry and oil exploration. A family of known scintillator crystals widely used is of the thallium-doped sodium iodide Tl:NaI type. This scintillating material, discovered in 1948 by Robert Hofstadter and which forms the basis of modern scintillators, still remains the predominant material in this field in spite of almost 50 years of research on other materials. However, these crystals have a scintillation decay which is not very fast. A material that is also used is CsI that, depending on the applications, may be used pure or doped either with thallium (“Tl”) or with sodium (“Na”). One family of scintillator crystals that has undergone considerable development is of the bismuth germanate (“BGO”) type. The crystals of the BGO family have high decay time constants, which limit the use of these crystals to low count rates. A more recent family of scintillator crystals was developed in the 1990s and is of the cerium-activated lutetium oxyorthosilicate Ce:LSO type. However these crystals are very heterogeneous and have very high melting points (about 2200 degrees Celsius). The development of new scintillating materials for improved performance is the subject of many studies. One of the parameters that it is desired to improve is the energy resolution. This is because in the majority of nuclear detector applications, good energy resolution is desired. The energy resolution of a nuclear radiation detector actually determines its ability to separate radiation energies which are very close. It is usually determined for a given detector at a given energy, such as the width at mid-height of the peak in question on an energy spectrum obtained from this detector, in relation to the energy at the centroid of the peak. The smaller the value of the energy resolution, the better the quality of the detector.
[0009] Nevertheless, lower values of resolution are of great benefit. For example, in the case of a detector used to analyze various radioactive isotopes, improved energy resolution enables improved discrimination of these isotopes. While thin film scintillators have limited utility in applications where energy resolution is needed in radiation detection, they have major applications in imaging systems such as X-ray imaging device.
[0010] X-ray imaging devices in which the scintillator for converting an X-ray into visible light, or the like, and the imaging devices for receiving the visible light, or the like, are used in combination and more particularly a resolution-variable X-ray imaging device whose resolution can be changed as occasion demands and an X-ray CT apparatus. As the X-ray imaging device for capturing an image by visualizing an X-ray, there are some devices that can sense directly an X-ray and others that can visualize an X-ray by using the scintillator and then capture an image by using the imaging device such as CCD, or the like. In this case high quantum yield and very short lifetimes are desirable.
[0011] Conventional neutron detectors typically include devices that operate as ionization chambers or proportional counters. Each of the available methods demonstrates different strengths, but all share the common goals of high neutron efficiency, minimum gamma-ray sensitivity or gamma/neutron discrimination. Other systems, including scintillators doped with 6 Li, or 10 B, have been examined with mixed results. One of the prime difficulties in these systems is the gamma-ray rejection characteristics of the system. In addition, many of the detector materials are air and water sensitive or the scintillators employ heavy elements that limit gamma-ray rejection or have slow response times thanks to the long relaxation times. Scintillators have the added complication that often single crystals are required to avoid light loss, making it difficult to add large amounts of boron or lithium to increase the neutron cross-section absorption. While there are obvious advantages to the use of solid-state neutron detectors, to date these are outweighed by their disadvantages. Coating scintillators onto three dimensional structures which can then be filled with neutron stooping material may provide a new class of neutron detector.
[0012] Yttrium orthovanadate (“YVO 4 ”) is an excellent polarizer and laser host material in its single-crystal form. Europium doping of YVO 4 results in a red phosphor used in cathode ray tubes and color television in its powdered form. Europium-doped YVO 4 thin films have been prepared through a variety of deposition techniques such as sol-gel process, CVD, PLD and microwave-assisted chemical solution deposition. YVO 4 films prepared with these methods suffer from lack of crystallographic orientation control and the incorporation of vanadium-poor or rich nonstoichiometric phases.
[0013] Preparation of thin film scintillators is a difficult process. Generally, scintillators have a complex chemical composition and many methods to prepare high quality thin films are based upon high vacuum techniques.
[0014] Chemical solution deposition techniques have been generally viewed as less capital intensive (see, Lange, “Chemical Solution Routes to Single-Crystal Thin Films”, Science, vol. 273, pp. 903-909, 1996 and Schwartz, “Chemical Solution Deposition of Perovskite Thin Films”, Chemistry of Materials, vol. 9, pp. 2325-2340, 1997). Also, chemical solution techniques are not generally limited to flat surfaces.
SUMMARY OF THE INVENTION
[0015] To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention provides a porous light-emitting composition having a porous structure having pores, an interior surface, and an exterior surface, and a film of a phosphor that coats said interior and exterior surfaces of said porous structure without substantially blocking the pores of said porous structure.
[0016] The invention also includes a porous light-emitting composition having a nanostructured support, a conformal coating of a high refractive index material on said nanostructured support, and a phosphor coating on the conformal coating.
[0017] The invention includes new porous light-emitting compositions that are phosphors on three dimensional substrates, and new phosphors based upon coated porous structures. The coated porous structure maintains porosity which may be filled with a liquid, gel, or solid. Filling the cavities with materials of refractive index that match the substrates refractive index can lead to enhanced light output for thick devices such as scintillator based radiation detectors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 shows a plot of an x-ray diffraction (“XRD”) of Eu-doped YVO 4 on display glass and c-cut sapphire.
[0019] FIG. 2 shows a plot of an emission spectrum (excitation at 280 nm) of Eu YVO 4 on display glass (2 coats; dashed line) and Anodisc® filter (1 coat; solid line).
[0020] FIG. 3 shows a selection excitation and emission spectra of Tb doped alumina on an Anodisc® filter at varying Tb concentrations.
[0021] FIG. 4 shows a plot of an emission spectrum (excitation at 300 nm) of Anodisc® filter with one coat of Eu:YVO 4 dry (solid) and wetted (dashed).
[0022] FIG. 5 shows emission spectra of Eu:YVO 4 coated silica inverse opal filled with CCl 4 in the cavities.
DETAILED DESCRIPTION
[0023] The present invention provides new porous light emitting compositions that include conformal films on porous substrates. The structure of the conformal film can be amorphous, composite, polycrystalline, nanocrystalline, or microcrystalline depending upon the chemistry of the solution, the substrate used for the film deposition and growth, and the post-thermal treatment conditions.
[0024] An aspect of the present invention involves the use of Polymer-Assisted Deposition (“PAD”), which employs a coating solution made by adding a metal precursor to a suitable polymer. The polymer actively binds the metal, encapsulating it to prevent chemical reactions that may lead to undesired phases of metal oxide. PAD is a low-cost chemical solution method and effectively eliminates problems such as uneven distribution of the metal oxide on the substrate, unwanted reactivity of the metal resulting in the formation of undesired phases, and the difficulty of obtaining the desired metal/metal ratios when coating a substrate with more than one metal oxide. The PAD technique is a bottom-up growth technique that enables coating complex 3-D structures.
[0025] It has been found that the metal-containing conformal films made in accordance with the present invention can be uniform throughout the porous structure and without clogging or filling the pores of the porous structure. This is in contrast to various prior techniques that often result in non-uniform coating, or incomplete complete coating of the porous structure or clogging or significant reduction of the surface area of the final nanocomposite. The application of this technique on nanostructured supports provides new light emitting materials.
[0026] Metal-containing films (the metal oxide, metal, the nitride and the like) of the present invention are conformal films, i.e., they are homogeneous films throughout the internal pores of the porous supports that do not greatly reduce the surface area by clogging pore openings.
[0027] Phosphors are often complex mixtures such as europium-doped yttrium vanadate or lanthanide-doped silicates that may include metals from more than one category. The conformal metal-containing films prepared by the present process can include a metal oxide with a single metal, can be a metal oxide with two metals or three metals or may be a metal oxide including four or more metals. Among the conformal metal oxides films that can be prepared by the present process are phosphor films including europium-doped yttrium vanadate, terbium-doped alumina, and the like.
[0028] Metal-containing films that can be prepared by the present process can include a metal-containing film with a single metal, can be a metal containing film with two metals or three metals or may be a metal containing film including four or more metals. Among the metal oxide phosphors that can be prepared by the present process are included europium doped yttrium vanadate, terbium-doped alumina and the like.
[0029] In one aspect of the present invention, composites can be prepared including with various additional additives to provide tailoring of the material properties. Among the additives can be nanoparticles, especially nanoparticles of various metals such as transition metals, lanthanide metals or main group metals, nanoparticles of various metal oxides including one or more metal such as a transition metal, a lanthanide metal or a main group metal, nanoparticles of various metal nitrides including one or more metal such as a transition metal, a lanthanide metal or a main group metal, nanoparticles of various metal carbides including one or more metal such as a transition metal, a lanthanide metal or a main group metal, nanoparticles of various metal chalcogenides including one or more metal such as a transition metal, a lanthanide metal or a main group metal, nanoparticles of various metal pnictogenides including one or more metal such as a transition metal, a lanthanide metal or a main group metal, nanoparticles of various metal borides including one or more metal such as a transition metal, a lanthanide metal or a main group metal, or nanoparticles of various metal silicides including one or more metal such as a transition metal, a lanthanide metal or a main group metal. Examples of such nanoparticles can include titanium dioxide, strontium oxide, erbium oxide and the like, such nanoparticles suitable for modifying the electronic properties of metal containing films of a different material.
[0030] Also, various quantum dot materials, e.g., cadmium selenide dots having a coating of zinc sulfide, such quantum dot materials being well known to those skilled in the art, may be added to the various metal containing films in accordance with the present invention.
[0031] In one embodiment of the present invention, the porous substrate can be an inverse opal structure based on an oxide framework. The oxide framework can consist of silica, borate, zirconium oxide, titanium oxide, and the like. The size of the cavities of the support framework can be varied from hundreds of microns down to tens of nanometers.
[0032] In one embodiment of the present invention, the porous substrate can be a porous alumina membrane. The size of the pores can be varied from microns down to nanometers.
[0033] In one embodiment of the present invention, the porous substrate can be a mesoporous silica structure. The size of the pores can be varied from microns down to 1 nanometer.
[0034] In one embodiment of the present invention, the porous substrate can be a mesoporous silica structure coated with simple metal oxides, not generally consider phosphors, that result in a new material that emits light. The size of the pores can be varied from microns down to 1 nanometer.
[0035] In one embodiment of the present invention, the resulting porous structure with the metal-containing coating from the PAD deposition may be subsequently filled with a liquid, gel or solid. The conformal coating does not fill the pore volume so that the pores may be filled with a subsequent step to add functionality including high Z materials for gamma-ray absorption, boron-containing materials for neutron absorption, materials with a refractive index to match the substrate in order to increase the light output of the phosphor and the like.
[0036] In one embodiment of the present invention, the nanoporous substrate can be coated first with a high refractive index material then a second layer of a phosphor can be added.
[0037] In one embodiment of the present invention, the nanoporous substrate can be coated first with a high refractive index material then multiple layers of phosphors can be added.
[0038] The post-thermal treatment conditions such as post-annealing temperature and ambient change in a wide range depending on the objectives of the materials deposited. For example, to grow oxide films of europium doped yttrium vanadate on porous alumina membranes or silica inverse opals, the temperature can be ramped up to 120° C. at 10°/min and held for 1 hour and then ramped the temperature to 450° C. at 10°/min and held for 1 hour to burn off the polymer. Finally the temperature can be ramped to 700° C. at 10°/min and held for 1 hour to cause a crystalline structure and enhance the luminescence of the phosphor.
[0039] Aqueous solutions containing polyethylenimine (“PEI”) bound to single metal ethylenediaminetetraaceticacid (“EDTA”) complexes were prepared, characterized by ICP and mixed to give the final solutions for coating. Thin films on display glass and quartz were prepared by spin coating and coatings on Anodisc® membrane filters were prepared by a dip coating method that allowed the solution to penetrate the pores of the alumina. The coated substrates were then thermally treated up to a temperature of 700° C. to induce crystallization of the Eu:YVO 4 . The resulting film composition, determined by Rutherford backscattering spectrometry (“RBS”), of Y 0.94 V 1.00 Eu 0.08 S 0.06 confirms the europium doping level and indicates the presence of residual sulfate from the vanadyl sulfate precursor used in preparing the vanadium solution. XRD of the films ( FIG. 1 ) shows only the expected peaks for YVO 4 . The fluorescence results ( FIG. 2 ) show strong red emission (for films with only 2 coats) from the 5 D 0 → 7 F 2 transition of europium at 618 nm indicating the europium is in a low symmetry environment as expected. There is no indication of phase separation in the films.
[0040] Ellipsometry results indicated film thickness of 152.3±2.5 nm for the 4 coats of Eu:YVO 4 on glass and 87.2±0.2 nm for the 2 coats of Eu:YVO 4 on c-cut sapphire with a roughness of 6.2±0.1 nm. Each single coat yields a film thickness of approximately 40 nm. AFM measurements gave MSR roughness values of 1.3 nm for the bare glass substrate, 6.0 nm for the Eu:YVO 4 film on glass and 4.1 nm for the Eu:YVO 4 film on c-cut sapphire. These MSR roughness values are as low as those obtained by PLD. This is astonishing considering the initial thermal process involves simply placing a spin coated substrate onto a hot surface at 550° C. for 30 seconds. During this time, water from the film is evaporated and the polymer is removed resulting in a remarkably clear, smooth film with no cracks.
[0041] Unlike many other deposition techniques, PAD is not a line-of-sight process. It is a solution technique that can coat all aspects of a surface. We chose to demonstrate the ability to coat deep narrow channels using the commercially available Anodisc® membrane filters made from Anapore® porous membranes. The membranes are initially 60 μm thick with a closely packed honeycomb of 200 nm diameter channels through the membrane. The pores in the membrane are not periodically arranged into a photonic lattice, but they have the same general dimensions used in photonic crystals. The solution readily wets into the pores by capillary action. The resulting materials have phosphor throughout the channels, and maintain porosity. Scanning Electron Microscopy (“SEM”) confirms the open pore structure. The porosity is further demonstrated by the fact that water is able to wet into and through the coated Anodisc® membrane filters resulting in high transparency. Other solution techniques such as sol-gel clog and fill pores as opposed to depositing conformal coatings. Anodisc® membrane filters with a single coating show the strong europium emission ( FIG. 2 ). These coated porous discs are highly luminescent and appear much brighter than the thin films on display glass. Part of this increased luminescence comes from reduced wave guiding on the porous material. Wave guiding at the surface interface in the thin films leads to strong luminescence at the edges but prevents light from exiting the surface when it hits the surface at an angles>the critical angle as defined by Snell's Law. Other effects such as increased absorption as the excitation light interacts with the walls of the channels and increased surface area may also factor in the remarkable emission.
[0042] Excitation and emission spectra were recorded for Eu:YVO 4 thin films coated on display glass. The sharp emission of europium is readily observed with 2 coats of Eu:YVO 4 on c-cut sapphire and one cat on a porous Anodisc® membrane filters ( FIG. 2 ). The excitation spectra of all of the coated materials have a peak at <300 nm that corresponds to the absorption of vanadate. The Anodisc® membrane filters were given a single coating of Eu:YVO 4 . The discs emit both dry and wet. Strong emission is observed from a completely wetted disc suggesting that surface quenching of the europium is not significant and refractive index matching helps limit scattering. FIG. 4 shows excitation emission spectra from coating another phosphor Tb doped alumina onto the Anodisc® membrane filters.
[0043] Coating onto inverse opals with 360 nm diameter cavities is also possible with high refractive index metal oxides (for example, coating of the silica-based inverse opals with zirconium oxide). Surface area measurements and SEMs confirm that the coating is conformal with open pores that maintain the high surface area.
[0044] Coating onto titanium-based inverse opals with 360 nm diameter cavities is also possible with high refractive index metal oxides (for example coating of the titanium-based inverse opals with zirconium oxide). Surface area measurements and SEMs confirm that the coating is conformal with open pores that maintain the high surface area.
[0045] Coating onto silica-based inverse opals with 360 nm diameter cavities was successful. FIG. 4 shows the fluorescence spectrum of Eu:YVO 4 coated onto the inverse opal structure. Surface area measurements and SEMs confirm that the coating is conformal with open pores that maintain the high surface area. These cavities can then be filled with CCl 4 which reduces the light scattering at the interfaces and maintains the strong emission seen in FIG. 5 .
[0046] Coating onto mesoporous silica (MCM-41) was also successful. Surface area measurements and SEMs confirm that the coating is conformal and the mesoporous silica still contains open pores that maintain the high surface area.
[0047] The present invention is more particularly described in the following EXAMPLES, which are intended as illustrative only, since numerous modifications and variations will be apparent to those skilled in the art.
[0048] Example A describes the preparation of solutions used in the deposition and formation of the metal-containing conformal films. Examples B through F describe the deposition of such conformal metal-containing films on porous supports. Polyethylenimine (“PEI”) was obtained from BASF as a water-free, branched, polymer with an average MW of 50,000. Water was deionized via reverse osmosis (having a resistivity >16 MOhms) (“MΩ”).
Example A
Solutions
[0049] A yttrium solution was prepared by mixing 1.3 g yttrium nitrate hexahydrate (99.9%, ALFA AESAR) with 1.0 g HEDTA (ALDRICH, 99.995% pure) and 1.0 g BASF polyethyleneimine polymer. The resulting solution was filtered through a 0.45 micron filter, diluted to 200 mL with nano pure water, and purified by Amicon filtration with a 3,000 MW cut-off filter. The final concentrated solution was 133 mM yttrium, determined by ICP/AES.
[0050] A europium solution was prepared by mixing 1.0 g of europium nitrate hexahydrate (99.9%, ACROS) with 1.0 g HEDTA (ALDRICH, 99.995% pure) and 1.0 g BASF polyethyleneimine polymer. The resulting solution was filtered through a 0.45 micron filter, diluted to 200 mL, and purified by Amicon filtration with a 3,000 MW cut-off filter. The final concentrated solution was 136 mM europium.
[0051] A vanadium solution was prepared by mixing 1.0 g vanadyl sulfate (ACROS) with 1.0 g HEDTA (ALDRICH, 99.995% pure) and 1.0 g BASF polyethyleneimine polymer. The resulting solution was filtered through a 0.45 micron filter, diluted to 200 mL, and purified by Amicon filtration with a 3,000 MW cut-off filter. The final concentrated solution was 230 mM vanadium, determined by ICP/AES.
[0052] A terbium solution was prepared by mixing 1 g terbium chloride TbCl 3 hexahydrate (99.9%, ACROS) with 1.0 g HEDTA (ALDRICH, 99.995% pure) and 1.0 g BASF polyethyleneimine polymer. The resulting solution was filtered through a 0.45 micron filter, diluted to 200 mL with nano pure water, and purified by Amicon filtration with a 3,000 MW cut-off filter. The final concentrated solution was 143 mM terbium, determined by ICP/AES.
[0053] An aluminum solution was prepared by mixing 2.0 g of aluminum nitrate nanohydrate (99.997%, ALDRICH) with 2.0 g HEDTA (ALDRICH, 99.995% pure) and 8.7 g of a 30% aqueous solution of polyethyleneimine polymer (POLY SCIENCES INC.). The resulting solution was filtered through a 0.45 micron filter, diluted to 200 mL, and purified by Amicon filtration with a 3,000 MW cut-off filter. The final concentrated solution was 180 mM aluminum.
[0054] A hafnium coating solution was prepared by mixing 2.0 g of HfOCl 2 (ALDRICH, 99.99% pure), 2.0 g HEDTA, 2 grams BASF polyethyleneimine polymer, and concentrated ammonium hydroxide (NH 4 OH (FISHER) in deionized (18 MOhms) H 2 O was added until the solution was clear. The resulting solution was filtered through a 0.45 micron filter, diluted to 200 mL with nano pure water, and purified by Amicon filtration with a 3,000 MW cut-off filter. The final concentrated solution was 163 mM Hf, determined by ICP/AES. This solution was rotovapped to further concentrate it, resulting in a final concentration of 250 mM Hf.
[0055] A titanium coating solution was prepared by mixing small aliquots of the titanium solution (a mixture of 2.5 g of 30% peroxide into 30 mL water and then slowly adding 2.5 g titanium tetrachloride) to a solution containing 1 g PEI, 1 g EDTA, and 30 mL water, while maintaining pH at 7.5, until precipitation occurred. The final Ti concentration was 408 mM.
[0056] A zirconium solution was prepared by mixing 2.04 g of zirconyl nitrate, (ZrO(NO 3 ) 2 , ALDRICH, 35 wt % Zr), 2.0 g HEDTA (ALDRICH, 99.995% pure), 2 grams BASF polyethyleneimine polymer, and concentrated ammonium hydroxide (NH 4 OH (FISHER) in deionized (18 MOhms) H 2 O was added until the solution was clear. The resulting solution was filtered through a 0.45 micron filter, diluted to 200 mL with nano pure water, and purified by Amicon filtration with a 3,000 MW cut-off filter. The final concentrated solution was 225 mM Zr, determined by ICP/AES.
[0057] A solution including zinc chloride, dipotassium ethylenediaminetetraaceticacid (“K 2 EDTA”) and PEI was prepared as follows. An aqueous solution of 2.0 grams of dipotassium ethylenediaminetetraaceticacid in 30 mL of water was prepared. To this solution was added 0.75 grams of zinc chloride and the solution was stirred. After stirring, 2 grams of polyethylenimine were added and the pH was adjusted to 9 with addition of 10% HCl. The solution was placed in an Amicon ultrafiltration unit containing a PM 10 ultrafiltration membrane designed to pass materials having a molecular weight <10,000 g/mol. The solution was diluted to 200 mL, and then concentrated by ultrafiltration to 20 mL in volume. Inductively coupled plasma-atomic emission spectroscopy showed that the final solution had 24.2 mg/mL of Zn.
Example B
[0058] P1-Photonic Crystals with one coat of YV/5% Eu were prepared as follows. SiO 2 crystals were coated with YV/5% Eu using the PAD method of coating. Coating solutions were made by mixing calculated volumes of each solution to obtain a 1:1 mol ratio of Y to V. A calculated volume of Eu solution was added to the Y/V solution to obtain a 5% mol ratio of Eu. 283 mg of the solution was then dropped onto 32 mg of P1 photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C. at 10°/min and held for 1 hour.
Example C
[0059] P1-Photonic Crystals with two coats of YV/5% Eu were prepared as follows. SiO 2 crystals were coated with YV/5% Eu using the PAD method of coating. Coating solutions were made by mixing calculated volumes of each solution to obtain a 1:1 mol ratio of Y to V. A calculated volume of Eu solution was added to the Y/V solution to obtain a 5% mol ratio of Eu. 194 mg of the solution was then dropped onto 32 mg of P1 photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C., 10°/min and held for 1 hour. The crystals were removed from the crucible and placed in a scintillation vial. Another 245 mg of YV/5% Eu solution were dropped onto the crystals with 1 coat of YV/5% Eu. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C., 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C. at 10°/min and held for 1 hour.
Example D
[0060] P3-Photonic Crystals with one coat of YV/5% Eu were prepared as follows. SiO 2 crystals were coated with YV/5% Eu using the PAD method of coating. Coating solutions were made by mixing calculated volumes of each solution to obtain a 1:1 mol ratio of Y to V. A calculated volume of Eu solution was added to the Y/V solution to obtain a 5% mol ratio of Eu. 228 mg of the solution was then dropped onto 32 mg of P3 photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C. at 10°/min and held for 1 hour.
Example E
[0061] Alumina anodiscs coated with 1 coat YV/5% Eu were prepared as follows. Anodisc porous alumina membranes were coated with a YV/5% Eu solution using the PAD method of coating. The membranes coated were 60 μm thick with a closely packed honeycomb of 200 nm diameter channels through the membrane. Membranes were wetted with the a coating solution made up of a 1:1 ratio of Y:V and 5% Eu. Coating solutions were made by mixing calculated volumes of each solution to obtain a 1:1 mol ratio of Y to V. A calculated volume of Eu solution was added to the Y/V solution to obtain a 5% mol ratio of Eu. A 60 μL volume of solution was placed on a glass slide, and the Anodisc® membrane filters were wetted with the solution by sliding them through the solution on the slide. The Anodisc® membrane filters were then placed on upside down ceramic crucibles and fired in a furnace in air with the following program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C. at 10°/min and held for 1 hour.
Example F
[0062] Alumina anodiscs coated with 1 coat Tb doped Aluminum were prepared as follows. Anodisc porous alumina membranes were coated with an aluminum solution doped with 1%, 3%, 5%, 7%, and 10% Tb using the PAD method of coating. The membranes coated were 60 μm thick with a closely packed honeycomb of 200 nm diameter channels through the membrane. Coating solutions were made by mixing calculated volumes of each solution to obtain a 1%, 3%, 5%, 7%, and 10% mol ratio of Tb. A 60 μL volume of solution was placed on a glass slide, and the Anodisc® membrane filters were wetted with the solution by sliding them through the solution on the slide. The Anodisc® membrane filters were then placed on upside down ceramic crucibles and fired in a furnace in air with the following program: The temperature was ramped to 120° C., 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C. at 10°/min and held for 1 hour.
Example G
[0063] P3-Photonic Crystals with one coat of YV/5% Eu were prepared as follows. TiO 2 crystals were coated with YV/5% Eu using the PAD method of coating. Coating solutions were made by mixing calculated volumes of each solution to obtain a 1:1 mol ratio of Y to V. A calculated volume of Eu solution was added to the Y/V solution to obtain a 5% mol ratio of Eu. 228 mg of the solution was then dropped onto 32 mg of photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C. at 10°/min and held for 1 hour.
Example H
[0064] Titania photonic crystals with one coat of YV/5% Eu were prepared as follows. TiO 2 crystals were coated with YV/5% Eu using the PAD method of coating. Coating solutions were made by mixing calculated volumes of each solution to obtain a 1:1 mol ratio of Y to V. A calculated volume of Eu solution was added to the Y/V solution to obtain a 5% mol ratio of Eu. 228 mg of the solution was then dropped onto 32 mg of P3 photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C. at 10°/min and held for 1 hour.
Example I
[0065] The zirconium-coated inverse opals were prepared by diluting 192 mg of the zirconium solution with 107 mg of deionized (18 MΩ) H 2 O. The solution was then dropped onto 32 mg of titanium oxide photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 500° C. at 10°/min and held for 1 hour.
Example J
[0066] The hafnium-coated inverse opals were prepared by taking 200 mg of the hafnium solution and diluting with 100 mg of deionized (18 MΩ) H 2 O. The solution was then dropped onto 32 mg of the titanium dioxide photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C., 10°/min and held for 1 hour. The temperature was ramped to 450° C., 10°/min and held for 1 hour. The temperature was ramped to 500° C., 10°/min and held for 1 hour.
Example K
[0067] The titanium-coated inverse opals were prepared by taking 200 mg of the titanium solution and diluting with 100 mg of deionized (18 MΩ) H 2 O. The solution was then dropped onto 32 mg of the titanium oxide photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C., 10°/min and held for 1 hour. The temperature was ramped to 500° C., 10°/min and held for 1 hour.
Example L
[0068] A first layer of hafnium was coated onto an inverse opal by taking 200 mg of the hafnium solution and diluting with 100 mg of deionized (18 MΩ) H 2 O. The solution was then dropped onto 32 mg of the titanium dioxide photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C., 10°/min and held for 1 hour. The temperature was ramped to 450° C., 10°/min and held for 1 hour. The temperature was ramped to 500° C., 10°/min and held for 1 hour. Then this material was coated with YV/5% Eu using the PAD method of coating. Coating solutions were made by mixing calculated volumes of each solution to obtain a 1:1 mol ratio of Y to V. A calculated volume of Eu solution was added to the Y/V solution to obtain a 5% mol ratio of Eu. 228 mg of the solution was then dropped onto 32 mg of photonic crystals in a 20-mL scintillation vial. The vial was rotated to ensure total coverage of the crystals by the coating solution. The coated crystals were then rotovapped under negative pressure in order to cause the solution to penetrate the cavities within the photonic crystals and remove excess water. When the crystals appeared dry, the crystals were transferred to a ceramic crucible. The crystals were then annealed in air with the following heating program: The temperature was ramped to 120° C. at 10°/min and held for 1 hour. The temperature was ramped to 450° C. at 10°/min and held for 1 hour. The temperature was ramped to 700° C. at 10°/min and held for 1 hour.
[0069] The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best 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. | Light-emitting devices are prepared by coating a porous substrate using a polymer-assisted deposition process. Solutions of metal precursor and soluble polymers having binding properties for metal precursor were coated onto porous substrates. The coated substrates were heated at high temperatures under a suitable atmosphere. The result was a substrate with a conformal coating that did not substantially block the pores of the substrate. |
The invention described herein was made in the course of work under a grant from the Department of Health, Education and Welfare, Grant No. R01 HD00072.
This is a continuation-in-part of copending patent application Ser. No. 887,326, filed Mar. 16, 1978, abandoned and incorporated herein by reference.
The present invention relates to a micro-method and means for the determination of steroids, in particular of dehydroepiandrosterone sulfate (DS), in human body liquids and to a new method and means for detection of abnormal adrenal androgen secretion in the differential diagnosis of excess or deficient androgen producing conditions (e.g., virilism, hirsutism, male precocious puberty or delayed puberty). Recently radioimmunoassay for the measurement of dehydroepiandrosterone sulfate has become available. The usefulness of this assay for the diagnosis of abnormal puberty has been established, (See, e.g., Korth-Schutz S, Levine LS, and New MI: Dehydroepiandrosterone sulfate (DS) levels, a rapid test for abnormal adrenal secretion. J. Clin. Endocrinol Metab 42: 1005,1976.). However, the prior art method for the determination of steroids involves the analysis of blood plasma and requires relatively large amounts of blood for the separation of the blood cell mass from the plasma. Further, sample collection by veno puncture is inconvenient in small infants.
In the recently developed radioimmunoassays (RIA), radiological means are employed to detect and/or measure the presence of a steroid in the patient's blood (or urine). In these radioimmunoassay tests, a solution of an antibody of the steroid is placed in contact with a mixture of the steroid, which has been extracted from a sample of the patient's body fluid to be tested and a known amount of the same steroid tagged with a radioactive isotope. The steroid in the test sample and the labeled steroid compete for interaction with the steroid antibody. The resulting steroids-antibody-complex is then separated from the fluid and either fraction may be analyzed radiologically in order to determine the respective proportions of the labeled and unlabeled steroid which became bound to the antibody. The concentration of steroid in the sample can be calculated from this information, since the proportion of labeled and unlabeled steroid will be in the same proportion in both fractions. The radioimmunoassay techniques exhibit a high degree of accuracy and specificity. Until recently the radioimmunoassay techniques required relatively large amounts of blood for the preliminary separation of blood plasma from the hematocrit, and also have the usual disadvantage that samples can be stored only at low temperature, since the liquid samples are easily infected and spoiled by growth of bacteria.
A new method developed and applied to the determination of 17α-hydroxy-progesterone for screening patients with congenital adrenal hyperplasia utilizes eluates of whole blood collected on filter paper. (Pang S., Hotchkiss J., Drash A. L., Levine L. S. and New. M.I.: Microfilter Paper Method for 17α-Hydroxyprogesterone Radioimmunoassay: Its Application for Rapid Screening for Congenital Adrenal Hyperplasia, J. Clin. Endocrinol. Metab. 45, 1003, 1977.). This method has the specificity, accuracy and precision of RIA in whole plasma. Further, it has been shown that concentrations of 17α-hydroxy-progesterone remain unchanged in dried filter paper blood samples when stored at room temperature for 21 days and, therefore, the filter paper with dried blood may be sent for steroid assay by mail. Although this approach overcomes many of the deficiencies of the prior art, the method includes an extraction step requiring the use of a volatile organic solvent necessary to isolate the steroid of interest. Additionally, a subsequent step requires separation of the residue from the organic solvent. These extra steps take time, can reduce yield and expose lab technicians to the hazards arising from the use of a volatile organic solvent.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for the determination of steroid hormones, in particular dehydroepiandrosterone sulfate in small samples of human body liquids collected on a sample absorbing sheet (e.g., filter paper), in particular, small blood samples, which avoids the disadvantages of the prior art methods.
It is a special object of the present invention, to provide such a method which can be rapidly performed and requires only minute amounts of blood which can be easily obtained, e.g., from the finger tip or with heel prick in small children.
It is a further object of the present invention to provide such a method for determining the dehydroepiandrosterone sulfate blood level of newborn infants.
It is a further object of the present invention to provide such a method, wherein the blood sample can easily be obtained by a practicing physician and then be mailed to steroid laboratories in medical centers, obviating the need for frozen storage, centrifugation, and special containers.
It is a further object of the present invention to provide a method for the determination of steroids in human body liquids, which is especially suited for surveying ambulatory patients.
In order to accomplish the foregoing objects according to the present invention, there is provided a method for determination of a steroid in a sample of a human body liquid, which comprises the steps of:
(a) transferring said liquid sample onto a sheet of material (e.g., filter paper) which is capable of uniformly absorbing said liquid sample;
(b) drying the sample-containing sheet;
(c) treating a portion of the dry sample-containing sheet, which is equivalent to a predetermined amount of the sample with an aqueous solvent in order to obtain a mixture wherein the dried blood is substantially redissolved in the aqueous solvent;
(d) contacting said mixture containing the steroid with an aqueous solution of an agent, capable of selectively binding said steroid in the presence of a radio-isotopically labeled steroid, whereby part of said labeled steroid and part of said unlabeled steroid, present in the sample, are bound by forming a complex with said binding agent. Following this step said bound steroids are separated from unbound steroids in said aqueous solution and the radioactivity of at least said separated binding agent-steroids-complex or said unbound steroids is measured to determine the concentration of said hormone as a function of the measured radioactivity.
The steroid-binding agent, which is employed in the method according to the present invention, for determining steroids in human body fluids, may be any reagent conventionally employed in immuno chemical methods, in particular antisera for the respective steroids which are conventionally used in radioimmunoassays. The preparation of antisera for the various steroid hormones is well known in the art and these antisera are commercially available. In applying this method for the determination of dehydroepiandrosterone sulfate in blood samples, the conventional antiserum for dehydroepiandrosterone sulfate is used.
The radioisotopically labeled steroid, which is used as an indicating means, may comprise different radioactive isotopes, e.g., 3 H or 14 C. For measuring the radioactivity, a conventional liquid scintillation counter, which is adapted for beta-counting, can be used.
The method for determining steroids according to the present invention, using only extremely small amounts of human body liquids, is especially suited for detecting unduly high amounts of steroid hormones in the human body and provides a simple means for detecting disorders in the body functions which are characterized by increased levels of steroids in the body, for example, hirsutism, virilism and disorders of puberty, etc.
The method for determining dehydroepiandrosterone sulfate in a small blood sample according to the present invention is particularly suitable as a rapid screening test for adnormal adrenal androgen secretion in differential diagnosis of virilization in childhood or in adults.
Further objects, features, and advantages of the present invention will become apparent from the detailed description of the invention and its preferred embodiments, which follows.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, there has been discovered a noval micromethod for determining the concentration of specific steroids in human body liquids, in particular, in small samples of whole blood. According to the present invention, a small amount of a human body liquid, in particular human whole blood, is collected on a sheet of absorbing material, preferably a standard filter paper, from which the steroid can later be eluted. The amount of steroid, which is recovered from the eluate, is then determined in a conventional radioimmunoassay. The method of applying a small blood sample on a filter paper is a standard hospital procedure in the screening for phenylketonurea in newborns and has also been used for screening neonates for hypothyroidism (see Larsen et al, Pediatr. Res. 9, 604, 1975). Yet, such a method of collecting a blood sample on a filter paper with subsequent elution of the blood from the filter paper, has never been used in connection with the process of extracting a steroid-containing fraction from blood samples and measurements of the steroid-content by radioimmunoassay.
It has now been found that the steroid content in a whole blood sample which has been absorbed and dried on an absorbing paper remains unchanged even if the blood-containing paper is stored at room temperature for a period of up to about one month. Even after such a long period of storage, the steroid-content of the blood sample can be completely recovered from the absorbing paper by elution of the dried blood-containing paper with an aqueous solution. For example, an excellent correlation has been found between the values of dehydroepiandrosterone sulfate obtained from blood samples of various subjects which were treated by a micro-filter-paper-method according to the present invention, and the values from plasma samples of whole blood samples, which were treated in a conventional procedure for radioimmunoassay tests in these same subjects.
In addition, blood samples on filter paper can easily be sent by surface mail by physicians practicing in geographically isolated areas to steroid laboratories in medical centers, obviating the need for frozen storage, centrifugation, and special containers. The method is suitable for the survey of ambulatory patients. In such situations, the family doctor could easily screen for a number of conditions and disorders, particularly for excessive steroid production, e.g., virilism of all kinds, Cushings syndrome, and possibly some adrenal and pituitary steroid deficient states. The presently claimed method is easy and rapid and has the specificity, accuracy, and precision of radioimmunoassays in whole plasma. The minute amount of blood which is required, the simplicity of sample collection which can be easily performed by heel prick, and the ease with which samples may be transported, make this method highly useful for large scale screenings.
Summarizing the foregoing, the micromethod, according to the present invention, using samples of whole dried blood on an absorbing paper, is superior to the serum hormone assays in the following ways:
i. the minute amounts of blood required by the method;
ii. the simplicity of sample collection, by either medical or non-medical personnel;
iii. absence of risk of accidental loss of samples by breakage of glass tubing;
iv. absence of need to centrifuge blood samples;
v. convenience of sample delivery by surface or air mail in an envelope;
vi. convenience of sample storage;
vii. practical application of this method for the measurement of specific steroids in mass screening programs.
For transferring the blood sample to the absorbing material according to the present invention, a blood sample can be collected directly onto a sheet of absorbing material from a small cut, for example, in the finger tip of a patient or by means of heel prick from a newborn infant. Of course, a small portion of a larger blood sample, which has been drawn from a human being directly into a heparinized tube in a conventional manner, can also be transferred onto an absorbing sheet to be used in the present test method.
The necessary amount of body liquid, in particular blood, which is used in the present test method, of course, varies, depending on the respective steroid which is to be tested, the sensitivity of the antiserum which is available for this steroid and the condition of the patient to be diagnosed, e.g., the expected level of the steroid in the body liquid of the patient. For example, to detect an abnormally increased level of dehydroepiandrosterone sulfate in blood, an amount of from about 10 to about 20 μl is preferably used. The absorbing material is preferably a uniformly absorbing filter paper. Example of suitably absorbing papers are filter paper No. 903 of Schleicher and Schuell or the standard absorbing paper which is used for collecting blood samples in the hospital as a standard procedure for neonatal screening for phenylketonurea. Such filter paper can absorb only a certain amount of liquid per surface area unit. When the body liquid, e.g., blood, is dropped gently on the filter paper, a standard size of filter paper disc will contain a standard amount of the liquid. Therefore, an identical volume of test samples of the body liquid, e.g., the blood, in various tests, can be insured by using the same kind of absorbing paper and punching out a a standard size disc of the dry blood-containing absorbing paper for the recovery of the steroid therefrom. It has been found, that the steroids are uniformly distributed throughout the paper area, which has been impregnated with the body liquid, e.g., the blood.
For eluting the steroid from filter paper containing dried whole blood, the latter is treated with an aqueous eluant. Water or aqueous salt solutions may be used as eluants. The eluant preferably is an aqueous buffer solution, having a pH-value of from about 6 to about 8, e.g., a sodium monophosphate/sodium diphosphate buffer solution. In order to effectively elute the whole amount of blood sample impregnated on the absorbing sheet, the elution preferably takes place at a temperature at 25° C., and then the steroid-containing eluate is subjected to a conventional radioimmunoassay test for determining the amount of the steroid therein.
The steroid-containing eluate is suitable for a radioimmunoassay determination of the amount of a steroid thereon, and optionally further purification of the steroid-containing eluate is possible, by extracting steroids with an organic solvent and conventional chromatographic methods, in order to eliminate components therein which will interfere with the radioimmunoassay test. Whether and to what extent a further purification of the steroid-containing eluate is necessary will depend on the selectivity (specificity) of the antiserum which is available for the steroid which is to be determined.
The conventional separation of the plasma from the hematocrit (=mass of the blood cells) of the blood sample is omitted in the method according to the present invention, as no interference from hematocrit components, e.g., from erythrocytes, is observed in the radioimmunoassay determination of the steroid. Further, it has been established that standard size of absorbing sheet contains a standard amount of serum or whole blood.
Radioimmunoassay techniques for the determination of the various steroid hormones are well known in the art. The steroid-containing eluates from body liquids, e.g., blood samples, which have been treated according to the present invention, can be tested in any of these conventional radioimmunoassay tests in the same manner as steroid fractions which have been recovered from body liquids, in particular blood plasma in a conventional way.
For example, to determine the dehydroepiandrosterone sulfate content of a blood sample according to the present invention, a sufficient solution of a known amount of radioisotopically labeled dehydroepiandrosterone sulfate, e.g., dehydroepiandrosterone (7- 3 H, net-033) in the same buffer solution and a sufficient solution of an amount of the antiserum for dehydroepiandrosterone sulfate in the same buffer solution is added to the steroid-containing eluate to bind an important portion, preferably between about 30 and about 50% of the radioisotopically labeled dehydroepiandrosterone sulfate.
In order to allow the formation of the steroid-antibody-complex, the mixture is incubated at about ambient temperature for a period of about 178 -2 hours and subsequently at ice bath temperature for a further period of about 30 minutes or overnight incubation at 40° C. (>12 hours). Subsequently, the free steroids are separated from the steroid-antibody-complex in a conventional manner, preferably by means of charcoal adsorption, and the radioactivity of the remaining steroid-antibody-complex solution is determined.
Finally, in another embodiment of the invention, there is provided a means for the determination of a steroid hormone in a sample of a human body liquid, comprising a first container, having therein
(a) an absorbing paper, adapted for absorbing a sample of the human body liquid;
(b) a second container, containing a first reagent, which comprises a radioisotopically labeled form of the steroid hormone; and
(c) a third container, containing a second reagent, comprising an antiserum for the steroid hormone.
In order to more fully describe the present invention, the method for determining the blood levels of dehydroepiandrosterone sulfate utilizing the present invention is described below. It is understood that the specific procedure is intended merely to be illustrative and in no sense limiting.
The dehydroepiandrosterone sulfate content in various samples of venous blood and of capillary blood of any subject is determined by the method according to the present invention, using blood elution from filter paper and in a conventional manner by using the plasma-fraction of the blood.
EXAMPLE 1
Specimens of whole venous or whole capillary blood from health volunteers and patients with endocrine disorders are analyzed. The dehydroepiandrosterone sulfate content is determined by radioimmunoassay in samples of the whole blood according to the method of the present invention and in samples of the plasma from the same whole blood.
1. Preparation in duplicate, of the whole blood sample for the radioimmunoassay to evaluate blood volume in the 1/8 inch disc specimen:
(a) 5 μl of the blood is pipetted onto a piece of filter paper no. 903 of Schleicher and Schuell, or filter paper used for screening for phenylketonurea:
(b) a drop of unknown volume of the same blood is put onto a second piece of the same filter paper;
(c) after the blood has dried, the entire blood-impregnated area of the piece of filter paper, which has been impregnated with 5 μl blood sample, is cut out and dropped into an extraction tube and a disc of 1/8-inch diameter from the blood impregnated area of the second filter paper piece is punched directly into another extraction tube by means of a paper puncher;
(d) 500 μl of a 0.01 M sodium/monophosphate/sodium diphosphate buffer solution, containing 0.1% of gelatin and 0.01% of sodium azide (=assay buffer solution) or distilled water is added to each of the extraction tubes. The tubes are then allowed to stand at room temperature for 15 to 30 minutes;
(e) aliquots of the resulting mixture are directly subjected to the radioimmunoassay test.
2. Preparation in duplicate, of the comparative plasma sample for the radioimmunoassay: The plasma is separated from the whole blood in a conventional hematocrit centrifuge and is diluted with the assay buffer solution or distilled water. An amount of the plasma-dilution, which is equivalent to 2.5 μl of plasma, is pipetted into an extraction tube and the volume of the plasma-dilution is brought up to 500 μl with the above buffer solution or distilled water aliquots of the resulting mixture are directly subjected to the radioimmunoassay test.
3. Radioimmunoassay:
Reactants:
Antiserum for dehydroepiandrosterone sulfate purchased from Dr. Guy Abraham of Harbor General Hospital, Torrance, Calif.
Radiolabeled dehydroepiandrosterone (DHA) (7- 3 H, net-033) (specific activity 25 Ci/mM) obtained from New England Nuclear.
Plasma blanks, containing no detectable amounts of dehydroepiandrosterone sulfate are obtained by treating plasma with dextran-coated charcoal (stripped plasma).
Whole blood blanks, dried on filter paper or whole blood itself, containing no detectable amounts of dehydroepiandrosterone sulfate are obtained from prepubertal patients undergoing dexamethasone administration.
All blanks are prepared as described above.
Test procedure
Known amounts of added labeled dehydroepiandrosterone sulfate (=DHA) in plasma and in filter paper specimens in quadruplicate were diluted with buffer solution and assayed. To study accuracy, known amounts of added unlabeled dehydroepiandrosterone sulfate were added to plamsa and to whole blood filter paper specimens in duplicate and assayed.
Standards and samples containing antibody and labeled hormone were incubated at room temperature for 11/2 hour and then placed in an ice bath for 15 to 30 minutes. Subsequently. 0.5 ml of charcoal dextran (=a suspension of 0.25% charcoal, 0.25% dextran in assay buffer solution stored at 4° C.), is added at 4° C. temperature. The mixture is briefly vortexed, incubated for 10 minutes and centrifuged at 4° C. at 3000 rpm for 10 minutes.
A standard curve is prepared with a range of concentrations between 0 and 10,000 pg, including diluted high standard steroid concentration.
The results are given in Tables I-VI below.
As depicted in Table I, dehydroepiandrosterone sulfate concentrations were below the sensitivity of the standard curve for blank specimens of plasma and filter paper eluate of whole blood as well as in the hemolysate or 20 μl of washed, packed red blood cells. This indicates an absence of a non-specific effect by either the red blood cells or the filter paper substance in the assay system.
Evaluation of the assay
The sensitivity of the standard curve, which was defined as the smallest amount of steroid standard which displaced labeled steroid significantly (P less than 0.001) was 19±4.2 pg as depicted in Table I.
The mean (±1 S.D.) percent recovery of added hormone to the filter paper blanks and plasma blank specimens were 101%±8 and 96%±10, respectively, as seen in Table II. The mean (±1 S.D.) recovery of varying concentrations of added unlabeled hormone in plasma blank preparations and dried filter paper blood preparations were 96%±10 and 114%±24, respectively, as shown in Table II. The inter-assay and intra-assay coefficient of variation for whole blood filter paper spots and for plasma samples does not exceed 13%, 11.4%, respectively.
To test the effect of time (days) and temperature, samples of dried whole blood on filter paper were stored at room temperature, and a 1/8-inch disc was obtained at 0, 7, 14, 21, and 30 days. The stability of the hormone in dried blood on filter paper specimens in five blood samples with varying steroid concentrations indicate that the concentration of steroid in the dried blood on filter paper remains substantially unchanged with a coefficient of variation less than 19% as illustrated by Table III.
The evaluation of plasma volume in the 1/8-inch disc of filter paper specimens is depicted in Table IV where an 3 H steroid was dissolved into whole blood samples with varying hematocrits and subsequently applied to filter paper from which a 1/8-inch disc was removed. Plasma from the remaining blood samples was separated and eluates of plasma aliquots (20 μl) and filter paper discs (1/8-inch) had radioactivity counts performed thereon. Plasma volume was calculated by comparing radioactivity measured in the disc samples to that of the plasma aliquots and the results indicate that a constant amount of plasma (1.44 to 1.90 μl; 1.72 μl in mean value) is absorbed by the standard size disc (1/8-inch), regardless of the red blood cell mass.
Table V depicts calculation of plasma volume in 1/8-inch discs of whole blood filter paper with varying hematocrits by RIA determination of steroid concentrations. Plasma volume (1.34 to 1.75 μl in mean value) in the 1/8-inch disc was similar to that obtained from the study of the recovery of radio-labeled steroid depicted by Table IV.
The comparison of steroid concentrations in simultaneously obtained venous and capillary blood samples is illustrated by Table IV, illustrating that the concentration was similar in both venous and capillary blood. To calculate plasma steroid concentrations in the disc samples, the mean plasma volume (1.66 μl) of the 1/8-inch disc from the study as shown in Tables IV and V, was used.
TABLE I__________________________________________________________________________ Read in 20 μl Read in hemo- of whole blood lysate of 20 μl Read in 20 μl on filter paper of packed washed Lowest limit (pg) plasma blank eluate blank red blood cells of sensitivityAssay n (pg) (pg) (pg) in standard curve__________________________________________________________________________DS 10 7.1 ± 3.6 7.0 ± 4.4 8.0 ± 3.3 19.0 ± 4.2__________________________________________________________________________
TABLE II______________________________________ Steroid PERCENT RECOVERY No. of added Plasma Whole blood blank Trials (pg) blank on filter paper______________________________________ 3.sub.H - 7 -- 96 ± 10.1 101 ± 8.0labeled DHADS 10 50 96 ± 10 114 ± 24 10 250 95 ± 13 107 ± 6 10 500 92 ± 12 100 ± 12 10 1000 84 ± 8 88 ± 7______________________________________
TABLE III__________________________________________________________________________ Steroid concentration (pg per 1/8 inch disk due at 25° C.) Coefficient ofHormoneSample Day 0 Day 7 Day 14 Day 21 Day 30 variation (%)__________________________________________________________________________DS 1 153 158 179 152 133 10.52 2,780 3,547 3,871 3,288 3,856 13.03 15,050 10,465 10,724 -- 10,546 19.04 19.942 19.018 18,387 19,229 13,122 15.0__________________________________________________________________________
TABLE IV______________________________________Hema- 3.sub.H (cpm) Calculated plasmaSter-Sam- tocrit 20 μl of whole blood volume (μl)oid ple % plasma in 1/8" disc in 1/8" disc______________________________________DS 1 27 2,456 220 1.792 34 1,569 113 1.443 36 2.951 268 1.814 40 2.858 272 1.905 44 3.142 249 1.586 46 3,229 288 1.78 Mean ± S.D. 1.72 ± 0.17______________________________________
TABLE V______________________________________Hema- Measured steroid (pg) Calculated plasmaSter-Sam- tocrit 20 μl Whole blood volume (μl)oid ple (%) plasma in 1/8" disc in 1/8" disc______________________________________DS 1 30 614 54 1.752 31 162 12 1.483 35 254 21 1.654 42 180 14 1.555 48 934 63 1.346 51 1,010 70 1.38 mean ± S.D. 1.52 ± 0.15______________________________________
TABLE VI______________________________________ Venous Blood Capillary Blood Eluate Eluate of 1/8" of 1/8" Coefficient ofSteroid Subject Plasma disc Plasma disc variation (%)______________________________________DS 1 248 220 -- 228 4.3 2 203 236 -- 185 12.4 3 403 453 -- 414 6.2______________________________________ | A method for determination of a steroid such as dehydroepiandrosterone sulfate (DS) in a sample of a human body liquid wherein the liquid sample is transferred to a sheet of microfilter paper and dried before being treated with an aqueous solvent to obtain a mixture wherein the dried body liquid is substantially redissolved in the aqueous solution. The mixture is contacted with an aqueous solution of an agent capable of selectively binding the steroid in the presence of a radioisotopically labeled form of steriod whereby part of the labeled steroid and part of the unlabeled steroid present in the sample are bound by forming a complex with the binding agent. Bound steroids are separated from unbound steroids in the aqueous solution and the radioactivity of at least the separated binding agent-steroids-complex or the unbound steroids is performed to determine the concentration of the hormone as a function of measured radioactivity. Additionally, a means for performing the method is disclosed. |
FIELD OF THE INVENTION
The present invention relates to a two-wire load control device, specifically a two-wire dimmer for electronic low-voltage (ELV) lighting loads.
BACKGROUND OF THE INVENTION
Low-voltage lighting, such as electronic low-voltage (ELV) and magnetic low-voltage (MLV) lighting, is becoming very popular. Low-voltage lamps allow for excellent, precise sources of illumination, extended lamp life, higher efficiencies than incandescent lamps, and unique lighting fixtures, such as track lighting. To power an electronic low-voltage lamp, an ELV transformer is required to reduce a line voltage (typically 120 V AC or 240 V AC ) to a low-voltage level (such as 12 volts or 24 volts) to power the ELV lamp.
Many prior art two-wire dimmers exist for control of ELV lighting loads. A conventional two-wire dimmer has two connections: a “hot” connection to an alternating-current (AC) power supply and a “dimmed hot” connection to the lighting load. Standard dimmers use one or more semiconductor switches, such as triacs or field effect transistors (FETs), to control the current delivered to the lighting load and thus control the intensity of the light. The semiconductor switches are typically coupled between the hot and dimmed hot connections of the dimmer.
Since an ELV transformer is normally characterized by a large capacitance across the primary winding, the ELV lighting load is typically dimmed using reverse phase-control dimming (often called “trailing-edge” dimming), in which the dimmer includes two FETs in anti-serial connection. One FET conducts during the first, positive half-cycle of the AC waveform and the other FET conducts during the second, negative half-cycle of the AC waveform. The FETs are alternately turned on at the beginning of each half-cycle of the AC power supply and then turned off at some time during the half-cycle depending upon the desired intensity of the lamp. To execute reverse phase-control dimming, many ELV dimmers include a microprocessor to control the switching of the FETs.
In order to provide a direct-current (DC) voltage to power the microprocessor and other low-voltage circuitry, the dimmer includes a power supply, such as a cat-ear power supply. A cat-ear power supply draws current only near the zero-crossings of the AC waveforms and derives its name from the shape of the waveform of the current that it draws from the AC supply. The power supply must draw current through the connected ELV lighting load. The FETs must both be turned off (non-conducting) at the times when the power supply is charging. So, the FETs cannot be turned on for the entire length of a half-cycle, even when the maximum voltage across the load is desired.
To ensure that the power supply is able to draw enough current to maintain its output voltage at all times, the FETs are turned off at the end of each half-cycle for at least a minimum off-time. The proper operation of the ELV dimmer is constrained by a number of worst-case operating conditions, such as high current draw by the low-voltage circuitry, worst-case line voltage input (i.e. when the AC power supply voltage is lower than normal), and worst-case load conditions (such as the number and the wattage of the lamps, the types of ELV transformers, and variations in the operating characteristics of the ELV transformers). By considering these worst-case conditions, the minimum off-time is determined by calculating the off-time that will guarantee that the power supply will charge fully for even the worst-case conditions. The resulting off-time generally ends up being a large portion of each half-cycle and constrains the maximum light level of the attached load.
However, the worst-case condition is not normally encountered in practice, and under typical conditions, the FETs could normally be turned off for a shorter amount of time at the end of each half-cycle, thus conducting current to the load for a greater amount of time resulting in a higher intensity of the load that is closer to the intensity achieved when only a standard wall switch is connected in series with the load. Prior art dimmers have held the minimum off-time constant under all conditions, and thus, have suffered from a small dimming range.
Thus, there exists a need for an ELV dimmer that includes a power supply and has an increased dimming range. More specifically, there exists a need for an ELV dimmer that includes a power supply and is able to drive an ELV lighting load above the maximum dimming level of prior art ELV dimmers without compromising the operation of the power supply.
SUMMARY OF THE INVENTION
According to the present invention, a two-wire dimmer for control of a lighting load from a source of AC voltage includes a semiconductor switch, a power supply, and a control circuit. The semiconductor switch is operable to be coupled between the source of AC voltage and the lighting load and has a conducting state and a non-conducting state. The power supply has an input that receives an input voltage and is operable to draw current from the source of AC voltage during the non-conducting state of the semiconductor switch. The control circuit is operable to control the semiconductor switch into the conducting state for an on-time each half-cycle of the AC voltage and is coupled to the input of the power supply for monitoring the input voltage of the power supply. The control circuit is operable to decrease the on-time when the input voltage of the power supply falls below a first predetermined level. Further, the control circuit is operable to increase the on-time when the input voltage rises above a second predetermined level greater than the first level.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified block diagram of the two-wire dimmer of the present invention;
FIG. 2 a is a waveform of the dimmed hot voltage of the dimmer of FIG. 1 ;
FIG. 2 b is a waveform of the voltage across the dimmer of FIG. 1 ;
FIG. 3 is a flowchart of the process implemented by a control circuit of the dimmer of FIG. 1 ;
FIG. 4 shows voltage waveforms of the dimmer of FIG. 1 during a first part of the process of FIG. 3 ; and
FIG. 5 shows voltage waveforms of the dimmer of FIG. 1 during a second part of the process of FIG. 3 .
DETAILED DESCRIPTION OF THE INVENTION
The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, there is shown in the drawings an embodiment that is presently preferred, in which like numerals represent similar parts throughout the several views of the drawings, it being understood, however, that the invention is not limited to the specific methods and instrumentalities disclosed.
FIG. 1 shows the two-wire dimmer 100 of the present invention, which is connected in series between an AC power supply 102 and an ELV lighting load 104 . The dimmer 100 has two connections: a HOT connection 106 to the AC power supply 102 and a DIMMED HOT connection 108 to the lighting load 104 . Since ELV loads operate at a low-voltage level (such as 12 volts or 24 volts), a step-down transformer XFMR is required for the ELV lamp 104 A. The ELV transformer XFMR is typically characterized by a large capacitance C ELV across the primary winding.
To control the AC voltage delivered to the ELV load 104 , two field-effect transistors (FETs) 110 , 112 are provided in anti-serial connection between the HOT terminal 106 and the DIMMED HOT terminal 108 . The first FET 110 conducts during the positive half-cycle of the AC waveform and the second FET 112 conducts during the negative half-cycle of the AC waveform. ELV lighting loads are dimmed using reverse-phase control dimming, in which the FETs are alternately turned on at the beginning of each half-cycle of the AC power supply and then turned off at some time during the half-cycle depending upon the desired intensity of the lamp. The conduction state of the FETs 110 , 112 is determined by a control circuit 114 that interfaces to the FETs through a gate drive circuit 116 . To execute reverse-phase control dimming, the control circuit 114 includes a microprocessor to control the switching of the FETs 110 , 112 .
The ELV dimmer also includes a plurality of buttons 118 for input from a user, and a plurality of light emitting diodes (LEDs) 120 for feedback to the user. The control circuit 114 determines the appropriate dimming level of the ELV lamp 104 A from the input from the buttons 118 .
A zero-cross circuit 122 provides a control signal to the control circuit 114 that identifies the zero-crossings of the AC supply voltage. A zero-crossing is defined as the time at which the AC supply voltage equals zero at the beginning of each half-cycle. The zero-cross circuit 122 receives the AC supply voltage through diode D 1 in the positive half-cycle and through diode D 2 in the negative half-cycle. The control circuit 114 determines when to turn off the FETs each half-cycle by timing from each zero-crossing of the AC supply voltage.
In order to provide a DC voltage (V CC ) to power the microprocessor of the control circuit 114 and the other low-voltage circuitry, the dimmer 100 includes a power supply 124 . The power supply 124 is only able to charge when the FETs 110 , 112 are both turned off (non-conducting) and there is a voltage potential across the dimmer. Since there are only two connections on a two-wire dimmer, the power supply must draw a leakage current through the connected ELV lighting load 104 . For example, during the positive half-cycle, current flows from the AC supply 102 through diode D 1 to the power supply 124 and then, via circuit common, out through the body diode of the second FET 112 and through the load 104 back to the AC supply. The power supply 124 may be implemented as a “cat-ear” power supply, which only draws current near the zero-crossings of the AC waveform, or as a standard switch-mode power supply.
In a typical two-wire dimmer, the power supply 124 is implemented as a “cat-ear” power supply, which only draws current near the zero-crossings of the AC waveforms. The power supply 124 has an input capacitor C 1 and an output capacitor C 2 . The output capacitor C 2 holds the output of the power supply Vcc at a constant DC voltage to provide power for the control circuit 114 . The input of the power supply 124 is coupled to the Hot and Dimmed Hot terminals through the two diodes D 1 , D 2 , such that the input capacitor C 1 charges during both the positive and negative half-cycles.
The dimmer 100 also includes a voltage divider that comprises two resistors R 1 , R 2 and is coupled between the input of the power supply 124 and circuit common. The voltage divider produces a sense voltage V S at the junction of the two resistors. The sense voltage V S is provided to the control circuit 114 such that the control circuit is able to monitor the voltage level at the input of the power supply 124 . The microprocessor in the control circuit 114 preferably includes an analog-to-digital converter (ADC) for sampling the value of the sense voltage V S . The resistors R 1 , R 2 are preferably sized to ensure that the maximum voltage at the pin of the microprocessor of the control circuit 114 does not exceed the power supply output V CC . For example, if the input voltage to the waveform is 240 V RMS and the power supply output V CC is 3.3 V DC , then the values of R 1 and R 2 can be sized to 450 kΩ and 3 kΩ, respectively, in order to ensure that the magnitude of the sense voltage is less than 3.3 V DC . Alternatively, the voltage divider could be coupled between the output voltage (or another operating voltage) of the power supply 124 and circuit common to provide a signal to the control circuit 114 that is representative of the present operating conditions of the power supply.
According to the present invention, the control circuit 114 monitors the sense voltage V S and decreases the conduction times of the FETs 110 , 112 when the sense voltage V S drops below a first predetermined voltage threshold V 1 . Further, the control circuit 114 increases the conduction times of the FETs 110 , 112 when the sense voltage then rises above a second predetermined voltage threshold V 2 , greater than the first threshold. In a preferred embodiment of the present invention (when used with an input voltage of 240 V RMS ), the first and second voltage thresholds V 1 and V 2 are set to 0.67 V DC and 0.8 V DC , respectively, which correspond to voltages of 100 V DC and 120 V DC at the input of the power supply 124 . Alternatively, if the microprocessor does not include an ADC, the dimmer 100 could include a hardware comparison circuit, including one or more comparator integrated circuits, to compare the sense voltage with the first and second voltage thresholds and then provide a logic signal to the microprocessor.
FIG. 2 a shows examples of a dimmed hot voltage 210 measured from the Dimmed Hot terminal 108 of the dimmer 100 to neutral (i.e. the voltage across the lighting load 104 ). The dashed line represents the AC voltage 220 measured across the AC power supply 102 . The period of the AC voltage 220 is split into two equal half-cycles having periods T H . The dimmed hot voltage 210 has a value equal to the AC voltage 220 during the time t ON when one of the FETs is conducting. Conversely, the dimmed hot voltage 210 has a value equal to zero during the time t OFF when neither FET is conducting. The control circuit 114 is able to control the intensity of the load by controlling the on-time t ON . The longer the FETs conduct during each half-cycle, the greater the intensity of the lighting load 104 will be.
FIG. 2 b shows an example of the dimmer voltage 230 measured from the Hot terminal 106 to the Dimmed Hot terminal 108 of the dimmer (i.e. the voltage across the dimmer). The power supply 124 is only able to charge during the off-time t OFF because the off-time is the only time during each half-cycle when there is a voltage potential across the FETs and thus across the power supply 124 . Conversely, when the FETs are conducting during the on-time t ON , the FETs form a low impedance path through the dimmer 100 and the input capacitor C 1 of the power supply 124 is unable to charge.
With prior art ELV dimmers, a maximum off-time t OFF-MAX-WC needed to charge the power supply during worst-case conditions was used to determine the maximum on-time t ON-MAX-WC of the dimmer. The worst-case conditions may include a low-line AC input voltage or a high current drawn from the power supply by the microprocessor and other low-voltage components. However, the dimmer is not always operating with the worst-case conditions and it may be possible to increase the on-time above the maximum on-time t ON-MAX-WC in order to provide a greater light output of the lighting load 104 at high-end.
The dimmer 100 of the present invention has a maximum on-time limit, t ON-MAX-LIMIT that is greater than the worst-case on-time t ON-MAX-WC . The maximum on-time limit t ON-MAX-LIMIT of the dimmer 100 is determined from the appropriate off-time required to charge the input capacitor C 1 of the power supply 124 during normal operating conditions. The dimmer 100 also has a dynamic maximum on-time, t ON-MAX , that the control circuit 114 is operable to control from one half-cycle to the next. The dynamic maximum on-time t ON-MAX cannot exceed the maximum on-time limit t ON-MAX-LIMIT , but can be decreased below the limit in order to increase the off-time of the FETs to allow the input capacitor C 1 of the power supply 124 more time to charge. By driving the on-time of the FETs above the worst-case on-time t ON-MAX-WC , the dimmer 100 of the present invention is able to achieve a greater light output of the connected lighting load 104 than prior art ELV dimmers. However, when the on-time of the FETs is greater than the worst-case on-time t ON-MAX-WC , there is a danger of the input capacitor C 1 not having enough time to charge in during the off-time of the half-cycle.
By monitoring the input of the power supply 124 , the control circuit 114 of the dimmer 100 of the present invention is able to determine when the input voltage has dropped to a level that is inappropriate for continued charging of the input capacitor C 1 . For example, if the sense voltage V S falls below a first voltage threshold V 1 , then the capacitor C 1 needs a greater time to properly charge and the on-time is decreased. On the other had, if the sense voltage V S remains above the first voltage threshold V 1 , the input capacitor C 1 is able to properly charge each half-cycle.
FIG. 3 shows a flowchart of the process for monitoring the sense voltage V S and determining whether to change the on-time t ON in response to the value of the sense voltage V S . The process of FIG. 3 runs each half-cycle of the AC voltage. The on-time t ON is changed in response to the maximum on-time t ON-MAX being decreased or increased if the maximum on-time is less than a desired on-time, t ON-DESIRED , of the dimmer. The desired on-time t ON-DESIRED is determined by the control circuit 114 from the inputs provided by the buttons 118 . The maximum on-time t ON-MAX is only changed if the sense voltage V S is below the first voltage threshold V 1 or if the sense voltage V S is above the second voltage threshold V 2 and the maximum on-time t ON-MAX has not returned to the maximum on-time limit, t ON-MAX-LIMIT , of the dimmer 100 .
The flowchart of FIG. 3 begins at step 310 at the beginning of each half-cycle. First, at step 312 , the sense voltage V S is sampled once immediately after the FETs are turned off. If the sampled sense voltage V S is less than the first voltage threshold V 1 at step 314 and the maximum on-time t ON-MAX is greater than the present on-time t ON at step 316 , the dimmer has detected that the sense voltage has dropped below the first voltage threshold V 1 . Then, the maximum on-time t ON-MAX is set to the present on-time t ON at step 318 and the maximum on-time t ON-MAX is decreased by a first predetermined time increment t 1 at step 320 . The first predetermined time increment t 1 preferably corresponds to 1% of the dimming range. If the maximum on-time t ON-MAX is less than the present on-time t ON at step 318 , the maximum on-time t ON-MAX is decreased by a first predetermined time increment t 1 at step 320 .
At step 322 , a determination is made as to whether the maximum on-time t ON-MAX is less than the desired on-time t ON-DESIRED . If so, the on-time t ON is set to the present value of the maximum on-time t ON-MAX at step 324 . Since the sense voltage is only sampled after the FETs are turned off (at step 312 ), the change to the on-time t ON at step 320 will affect the on-time of the dimmed hot voltage during the next half-cycle. The process then exits at step 326 for the current half-cycle to begin again at the beginning of the next half-cycle. If the maximum on-time t ON-MAX is greater than the desired on-time t ON-DESIRED at step 322 , then the dimmer has returned to normal operating conditions. The desired on-time t ON-DESIRED is used as the on-time at step 328 and the process exits at step 326 .
If the sense voltage V S is greater than the first voltage threshold V 1 at step 314 and the sense voltage is less than the second voltage threshold V 2 at step 330 , then the maximum on-time t ON-MAX and thus the on-time t ON are not changed. If the sense voltage V S is greater than the second voltage threshold V 2 at step 330 , the process moves to step 332 where a determination is made as to whether the present maximum on-time t ON-MAX is less than the maximum on-time limit t ON-MAX-LIMIT . If not, the maximum on-time t ON-MAX has returned to the limit and the maximum on-time t ON-MAX and the on-time t ON are not changed. However, if the present maximum on-time t ON-MAX is greater than the maximum on-time limit t ON-MAX-LIMIT at step 332 , then the maximum on-time t ON-MAX is increased by a second predetermined time increment t 2 for the next half-cycle at step 334 . The second predetermined time increment t 2 preferably corresponds to 0.5% of the dimming range.
FIG. 4 shows the voltage waveforms of the dimmer 100 operating with in accordance with the present invention as the voltage at the input of the power supply 124 is falling. The upper waveform shows the dimmed hot voltage, which is across the ELV load 104 . In the first few line cycles (a), (b), (c), and (d), the dimmed hot voltage is zero for only a small off-time at the end of each half-cycle. The lower waveform shows the sense voltage V S , which is a scaled version of the voltage at the input of the power supply 124 . During the off-time each half-cycle, the input capacitor C 1 of the power supply 124 charges and the sense voltage rises. During the first few cycles (a), (b), (c), the sense voltage remains above the first voltage threshold V 1 .
During the fourth half-cycle (d), the sense voltage falls below the first voltage threshold V 1 . The control circuit 114 decreases the on-time of the dimmed hot voltage during the next half-cycle (e) by the first time increment t 1 . Thus, the input capacitor C 1 has more time to charge during the off-time of the next half-cycle (e).
However, during the half-cycle (e), the sense voltage once again falls below the first voltage threshold V 1 . So, the control circuit 114 decreases the on-time of the dimmed hot voltage during the next half-cycle (f) by the first time increment t 1 . The cycle repeats again until the sense voltage does not fall below the first voltage threshold V 1 during the half-cycle (g). Now, the on-time of the dimmed hot waveform is held constant through the next half-cycles (h), (i).
FIG. 5 shows the voltage waveforms of the dimmer 100 after a low-voltage condition has been detected and the sense voltage V S is rising. The on-time of the first few half-cycles (j), (k), (l), (m), (n) of the dimmed hot waveform (the upper waveform of FIG. 5 ) is the decreased on-time (that was determined from the description of FIG. 4 ). Now, the voltage at the input of the power supply 124 , and thus the sense voltage V S , is rising (as shown in the lower waveform of FIG. 5 ).
During half-cycle (n), the sense voltage remains above the second voltage threshold V 2 . Therefore, the control circuit 114 increases the maximum on-time of the dimmed hot waveform during the next half-cycle (o) by the second time increment t 2 . While the sense voltage continues to remain above the second voltage threshold V 2 , the control circuit 114 continues increasing the maximum on-time each half-cycle by the second time interval t 2 until the maximum on-time is equal to the original maximum on-time.
The dimmer 100 of the present invention has been described such that the control circuit 114 is operable to change the maximum on-time t ON-MAX from one half-cycle to the next. However, it may be preferable to only change the maximum on-time t ON-MAX from one line-cycle to the next. Many dimmers are operable to drive multiple types of lighting loads. Some lighting loads, such as magnetic low-voltage (MLV) lighting loads, are susceptible to asymmetries that produce a DC component in the voltage across the load. For example, the magnetic low-voltage transformers required for MLV lighting may saturate and overheat when the load voltage has a DC component. When the on-time is changed from one half-cycle to the next, the voltage across the lighting load with be asymmetric and a DC component will be present in the voltage. On the other hand, when the on-time is only changed from one line-cycle to the next, the load voltage will remain symmetric and the problem of saturating or overheating the MLV transformer will be avoided.
While the dimmer 100 of the present invention was described primarily in regards to control of ELV loads, the dimmer may be used to control other load types, for example, incandescent or MLV loads.
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims. | A two-wire dimmer for control of a lighting load from an alternating-current (AC) power source includes a semiconductor switch, a power supply, and a control circuit. The power supply includes an energy storage input capacitor that is able to charge only when the semiconductor switch is non-conductive. The control circuit continuously monitors the voltage on the input capacitor and automatically decreases the maximum allowable conduction time of the semiconductor switch when the voltage falls to a level that will not guarantee proper operation of the power supply. The dimmer of the present invention is able to provide the maximum possible conduction time of the semiconductor switch at high end (i.e., maximum light intensity) while simultaneously ensuring sufficient charging time for proper operation of the power supply, and hence, the dimmer. |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the general field of gas turbine casings, and more particularly holding casings of gas turbine fans for aeronautical engines.
[0002] In a gas turbine aeronautical engine, a fan casing fulfils a number of functions. It defines the incoming air stream to the engine, supports abradable material with respect to the tip of the fan vanes, supports an optional structure for sound wave absorption for acoustic inlet treatment of the engine and incorporates or supports a holding shield. The latter comprises a trap for catching debris such as ingested items or fragments of damaged vanes thrown out by centrifuge action to prevent them from passing through the casing and reaching other parts of the aircraft.
[0003] Making a casing for holding a fan made of composite material has already been proposed. Reference could be made to document EP 1 961 923 which describes the production of a casing made of composite material of evolutive thickness, comprising the formation of a fibrous reinforcement by superposed layers of a fibrous texture and densification of the fibrous reinforcement by a matrix. According to this invention, the fibrous texture is made by three-dimensional weaving with evolutive thickness and is wound in several superposed layers onto a mandrel having a central wall of profile corresponding to that of the casing to be manufactured and two lateral flanges of profile corresponding to those of the external flanges of the casing. The resulting fibrous preform is held on the mandrel and impregnation by resin is completed under vacuum prior to polymerisation. The winding on a mandrel of a woven texture of evolutive thickness as described in this document directly gives a tubular preform having the preferred profile with variable thickness.
[0004] In practice, the resin impregnation step conducted under vacuum requires a supple envelope (or liner) to be applied to all the fibrous reinforcement, and especially at the level of the flanges of the reinforcement which will later form the external flanges of the casing. A difference in pressure is then set between the exterior and the space delimited by the mandrel and the liner containing the fibrous reinforcement. The injection of resin into this space can then start.
[0005] During this step, it was noted that setting the vacuum tends to generate tension in the layers of fibrous texture positioned at the level of the angles of flanges between the flanges and the central wall of the mandrel, this tension setting causing the fabrics to unstick at the origin of resin compaction and mass defects between the layers.
Aim and Summary of the Invention
[0006] The main aim of the present invention is therefore to rectify such drawbacks by proposing a solution for impregnation by vacuum liner ensuring uniform compaction of the fibrous reinforcement, especially at the level of the angles of flanges.
[0007] This aim is attained by an impregnation mandrel for making a gas turbine casing made of composite material, comprising:
an impregnation mandrel on which is intended to be held a fibrous reinforcement formed by superposed layers of a fibrous texture, the mandrel comprising a central annular wall the profile of which corresponds to that of the casing to be manufactured and two lateral flanges whereof the profiles correspond to those of external flanges of the casing to be manufactured; compaction bars each comprising a corner intended to be supported against the part of the fibrous reinforcement covering the angles formed between the central wall and the flanges of the mandrel, and a coupling flange intended to be fixed on the corresponding flange of the mandrel; a supple envelope forming a vacuum liner intended to be applied at least to that part of the fibrous reinforcement covering the central wall of the mandrel; and means for injecting resin into a space delimited between the vacuum liner and the mandrel at a longitudinal end of the fibrous reinforcement and for extracting it at an opposite end.
[0012] The compaction bars of the mandrel according to the invention are positioned once the winding operation is completed and before placing of the vacuum liner. These compaction bars ensure uniform compaction of the part of the fibrous reinforcement covering the angles of flanges prior to setting the vacuum. In this way, any risk of formation of resin mass between the layers of the fibrous reinforcement during this operation for setting the vacuum can be prevented.
[0013] Also, the compaction bars are intended to be fixed directly on the impregnation mandrel, which properly and repeatedly controls the geometry of the external flanges of the casing to be manufactured.
[0014] The mandrel preferably comprises at least one resin injection orifice terminating inside the space delimited between the vacuum liner and the mandrel at a longitudinal end of the fibrous reinforcement, and at least one resin extraction orifice placed at the longitudinal end of the fibrous reinforcement opposite to where the resin injection orifice terminates.
[0015] In this case, the resin injection orifice can be formed in one of the flanges of the mandrel and the resin extraction orifice can be formed in the other flange. Advantageously, the resin injection orifice terminates at the corner of a so-called injection compaction bar, whereas the resin extraction orifice terminates downstream of the so-called extraction opposite compaction bars.
[0016] The coupling flanges of the extraction compaction bars may comprise grooves ensuring passage of the resin.
[0017] The vacuum liner can be intended to be also applied to the compaction bars and be fixed tightly by its free ends to the flanges of the mandrel.
[0018] The coupling flanges of the compaction bars are preferably intended to be fixed tightly on the flanges of the mandrel.
[0019] For each flange of the mandrel, there can be four compaction bars and they can be put end to end angularly to cover the total circumference of the mandrel.
[0020] Another aim of the invention is a winding machine of a fibrous texture on an impregnation mandrel, comprising a take-up mandrel on which a fibrous texture is intended to be stored, produced by three-dimensional weaving, the take-up mandrel having a substantially horizontal axis of rotation, an impregnation mandrel such as defined previously, the impregnation mandrel having a substantially horizontal axis of rotation parallel to the axis of rotation of the take-up mandrel, electric motors for driving the mandrels in rotation about their respective axis of rotation, and a control unit of the electric motors for driving the mandrels in rotation.
BRIEF DESCRIPTION OF THE DIAGRAMS
[0021] Other characteristics and advantages of the present invention will emerge from the following description, in reference to the attached diagrams which illustrate an embodiment devoid of any limiting character, in which:
[0022] FIG. 1 is a schematic view and side elevation of a winding machine of a fibrous texture on an impregnation mandrel according to the invention;
[0023] FIG. 2 is a view of the impregnation mandrel of the winding machine of FIG. 1 during placing of the compaction bars;
[0024] FIG. 3 is a sectional view along of FIG. 2 ; and
[0025] FIG. 4 is a sectional view of the impregnation mandrel of FIG. 3 after placing of the vacuum liner.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The invention will now be described within the scope of its application to the production of a fan casing in an aeronautical engine with a gas turbine.
[0027] An example of a manufacturing process of such a fan casing is described in document EP 1 961 923 which can be referred to.
[0028] The casing is made of composite material with fibrous reinforcement densified by a matrix. The reinforcement is made of fibres such as carbon, glass, aramide or ceramic and the matrix is made of polymer, for example epoxide, bismaleimide or polyimide.
[0029] Briefly, the manufacturing process described in this document consists of making a fibrous texture by three-dimensional weaving with chain take-up on a drum (hereinbelow called take-up mandrel) having a profile determined as a function of the profile of the casing to be manufactured.
[0030] The resulting fibrous texture is then transferred to the mandrel of a resin injection mould (hereinbelow called impregnation mandrel) the external profile of which corresponds to the internal profile of the casing to be manufactured.
[0031] While the preform is held on the impregnation mandrel, impregnation is then done with resin. For this purpose, a supple envelope (also called vacuum liner) is applied tightly to the preform and the resin is injected into the resulting mould. Impregnation is assisted by a difference in pressure being set between the exterior and the interior of the mould containing the preform (air vacuum). After impregnation, a resin polymerisation step is carried out.
[0032] The invention applies to any type of winding machine whereof the function is automated transfer of the fibrous texture stored on the take-up mandrel to the impregnation mandrel of the resin injection mould, such as shown in FIG. 1 .
[0033] Reference could be made to patent application FR 11 53212 (not yet published) which describes in detail the structure and operation of such a machine.
[0034] Briefly, the winding machine 10 comprises a frame 12 supporting especially a take-up mandrel 14 and an impregnation mandrel 100 according to the invention. These mandrels are removable, that is, they can be dismantled from the frame.
[0035] The take-up mandrel 14 receives the fibrous texture 16 produced for example by three-dimensional weaving. It is borne by a horizontal axle 18 one end of which is mounted to rotate on the frame 12 of the winding machine and the other end is coupled to the output shaft of an electric engine 20 , for example an electric motoreducer on alternating current.
[0036] The assembly constituted by the take-up mandrel 14 , its axle 18 and its electric engine 20 can translate relative to the frame along the axis of rotation of the take-up mandrel. This degree of liberty in translation of the take-up mandrel creates alignment of this mandrel on the impregnation mandrel prior to winding of the fibrous texture on the impregnation mandrel.
[0037] The impregnation mandrel 100 of the winding machine is intended to receive the fibrous texture stored on the take-up mandrel, in superposed layers. In a way known per se, it has a central annular wall 102 whereof the profile of the external surface corresponds to that of the internal surface of the casing to be made and two lateral flanges 104 a, 104 b whereof the profiles correspond to those of the external flanges of the casing at its upstream and downstream ends to enable it to be mounted and linked to other elements.
[0038] The impregnation mandrel is borne by a horizontal axis 22 which is parallel to the axis of rotation 18 of the take-up mandrel and whereof one end is mounted to rotate on the frame 12 of the winding machine and the other end is coupled to the output shaft of an electric engine 24 , for example an electric motoreducer on alternating current.
[0039] A control unit 26 is connected to the electric motors 20 , 24 of the two mandrels and controls the rotation speed of each mandrel. More generally, this control unit controls the assembly of operating parameters of the winding machine, and especially the displacement in translation of the take-up mandrel when motorised.
[0040] With such a machine, winding of the fibrous texture on the impregnation mandrel is done as follows: the free end of the fibrous texture of the take-up mandrel is first fixed on the impregnation mandrel by means of a device for holding by clamping described hereinbelow, then the engines for driving the mandrels in rotation are activated and controlled by the control unit so as to apply adequate winding tension on the fibrous texture.
[0041] Winding of the fibrous texture in superposed layers on the impregnation mandrel can then start and be executed in the direction of rotation marked by arrow F in FIG. 1 . By way of example, it might be necessary to effect 4 turns ⅛ to produce a fibrous reinforcement 28 having a thickness conforming to the specifications of the casing to be manufactured.
[0042] According to the invention, the impregnation mandrel 100 is provided with means ensuring impregnation by resin under vacuum liner on completion of the winding operation.
[0043] More precisely, as shown in FIGS. 2 to 4 , the impregnation mandrel comprises so-called angular compaction bars which are intended to be positioned on the mandrel at the level of the parts of the fibrous reinforcement 28 covering the angles formed between the central wall 102 and the flanges 104 a, 104 b of the latter.
[0044] These bars comprise a first series of compaction bars 106 a intended to be mounted against the part of the fibrous reinforcement covering the angle formed between the central wall of the mandrel and the flange 104 a, and a second series of compaction bars 106 b intended to be mounted against the part of the fibrous reinforcement covering the angle formed between the central wall of the mandrel and the other flange 104 b .
[0045] The compaction bars 106 a, 106 b of these series cover the entire circumference of the mandrel and are sectored. So, in the example illustrated in FIG. 2 , each series comprises four compaction bars each extending over 90° approximately and put end to end angularly to cover the total circumference of the impregnation mandrel. Of course, the number of bars per series could be different.
[0046] Each compaction bar 106 a, 106 b comprises a corner 108 a , 108 b which is intended to be supported against the part of the fibrous reinforcement covering the angles formed between the central wall 102 and the flanges 104 a, 104 b of the mandrel, and a coupling flange 110 a, 110 b intended to be fixed on the corresponding flange of the mandrel.
[0047] Placing the compaction bars on the impregnation mandrel ensures uniform compaction of the fibrous reinforcement at the level of the flange angles. This placing can be ensured by using a specific tool of tension type, for example.
[0048] Once in place, the compaction bars are fixed on the impregnation mandrel by means of their coupling flanges 110 a , 110 b and by means for example of screws 112 . This fixing is made tight by the presence of O-ring joints 114 positioned against an internal face of the coupling flanges about the boreholes made for passage of screws and plugs 116 sealing the openings made in the coupling flanges for passage of these same screws.
[0049] A supple envelope 118 forming a vacuum liner is then applied to at least that part of the fibrous reinforcement covering the central wall of the mandrel. As shown in FIG. 4 , this vacuum liner 118 is preferably applied at the same time to the fibrous reinforcement at the level of the central part of the mandrel, but also covers the compaction bars 106 a, 106 b, at the level of its free ends, to be fixed tightly on the flanges 104 a, 104 b of the mandrel. The material used to make the vacuum liner 118 is for example nylon (the choice of material will depend especially on the class of temperature of the resin).
[0050] The impregnation mandrel further comprises means for injecting resin into the resulting mould. For this purpose, one of the flanges of the mandrel (here the flange 104 a ) comprises at least one resin injection orifice 120 which terminates inside a space 122 delimited between the corner 108 a of a corresponding compaction bar 106 a (also called “injection compaction bar”) and the corresponding flange 104 a . In this way, the injection of resin is done at the level of one of the free ends of the fibrous reinforcement 28 held on the mandrel.
[0051] The resin is extracted at the level of the opposite flange (specifically here flange 104 b ). For this purpose, this flange comprises one or more extraction orifices 124 which terminate in a space delimited between the free end opposite the vacuum liner 118 and the flange 104 b, this space being situated downstream of the corresponding compaction bars 106 b (also called “extraction compaction bars”). Downstream here means relative to the flow of the resin between the two longitudinal ends of the fibrous reinforcement held on the mandrel.
[0052] To allow the resin to pass from the fibrous reinforcement 28 to the extraction orifice or the extraction orifices 124 , it is necessary for it to get over the extraction compaction bars 106 b. At the level of their internal face, the coupling flanges 110 b of the latter also have a plurality of grooves 126 (see FIG. 3 ) extending radially outwards and dimensioned to allow such passage of resin.
[0053] Also, it is evident that the extraction orifice or the extraction orifices can be used to set up the vacuuming of the liner 118 by creating a difference in pressure between the exterior and the space delimited by the mandrel and the liner containing the fibrous reinforcement. For this purpose, it might be necessary to place vacuum drainage fabric between the vacuum liner and the flange 104 b of the mandrel in its part downstream of the extraction compaction bars 106 b (such fabric prevents discontinuity of the vacuum as far as the extraction orifices). Setting vacuum assists the resin injection operation.
[0054] Once the vacuum is set, the resin is injected into the mould formed by the impregnation mandrel covered by the vacuum liner. On completion of this operation, a resin polymerisation step is conducted as known per se. | An impregnation mandrel for production of a gas turbine casing made from composite material, including: a mandrel having a central wall and two side plates; compaction bars, each including (i) a wedge configured to bear against a fibrous reinforcing part covering angles formed between the central wall and the side plates of the mandrel, and (ii) an attachment flange configured to be attached to the corresponding side plate of the mandrel; a flexible casing forming a vacuum bag and configured to be applied at least against the fibrous reinforcing part covering the central wall of the mandrel; and a mechanism for injecting resin into a space defined between the vacuum bag and the mandrel at one of longitudinal ends of the fibrous reinforcement and for extracting the resin at the opposite end. |
RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 13/754,807 filed on Jan. 30, 2013, which is a continuation of U.S. patent application Ser. No. 13/430,650 filed on Mar. 26, 2012, now U.S. Pat. No. 8,675,590, which is a continuation of U.S. patent application Ser. No. 12/699,846 filed on Feb. 3, 2010, now U.S. Pat. No. 8,149,829, which is a continuation of U.S. patent application Ser. No. 11/728,246 filed on Mar. 23, 2007, now U.S. Pat. No. 7,756,129, which is a continuation of U.S. patent application Ser. No. 10/894,406 filed on Jul. 19, 2004, now U.S. Pat. No. 7,218,633, which is a continuation of U.S. patent application Ser. No. 09/535,591 filed on Mar. 27, 2000, now U.S. Pat. No. 6,804,232, which is related to U.S. patent application Ser. No. 09/536,191 filed on Mar. 27, 2000, all of which are incorporated herein by reference in their entirety for all purposes.
BACKGROUND AND FIELD OF THE INVENTION
A. Field of the Invention
The present invention relates to networking and, more particularly, to a data network.
B. Description of Related Art
Over the last decade, the size and power consumption of digital electronic devices has been progressively reduced. For example, personal computers have evolved from laptops and notebooks into hand-held or belt-carriable devices commonly referred to as personal digital assistants (PDAs). One area of carriable devices that has remained troublesome, however, is the coupling of peripheral devices or sensors to the main processing unit of the PDA. Generally, such coupling is performed through the use of connecting cables. The connecting cables restrict the handling of a peripheral in such a manner as to lose many of the advantages inherent in the PDA's small size and light weight. For a sensor, for example, that occasionally comes into contact with the PDA, the use of cables is particularly undesirable.
While some conventional systems have proposed linking a keyboard or a mouse to a main processing unit using infrared or radio frequency (RF) communications, such systems have typically been limited to a single peripheral unit with a dedicated channel of low capacity.
Based on the foregoing, it is desirable to develop a low power data network that provides highly reliable bidirectional data communication between a host or server processor unit and a varying number of peripheral units and/or sensors while avoiding interference from nearby similar systems.
SUMMARY OF THE INVENTION
Systems and methods consistent with the present invention address this need by providing a wireless personal area network that permits a host unit to communicate with peripheral units with minimal interference from neighboring systems.
A system consistent with the present invention includes a hub device and at least one unattached peripheral device. The unattached peripheral device transmits an attach request to the hub device with a selected address, receives a new address from the hub device to identify the unattached peripheral device, and communicates with the hub device using the new address.
In another implementation consistent with the present invention, a method for attaching an unattached peripheral device to a network having a hub device connected to multiple peripheral devices, includes receiving an attach request from the unattached peripheral device, the attach request identifying the unattached peripheral device to the hub device; generating a new address to identify the unattached peripheral device in response to the received attach request; sending the new address to the unattached peripheral device; and sending a confirmation message to the unattached peripheral device using the new address to attach the unattached peripheral device.
In yet another implementation consistent with the present invention, a method for attaching an unattached peripheral device to a network having a hub device connected to a set of peripheral devices, includes transmitting an attach request with a selected address to the hub device; receiving a new address from the hub device to identify the unattached peripheral device; and attaching to the network using the new address.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, explain the invention. In the drawings:
FIG. 1 is a diagram of a personal area network (PAN) in which systems and methods consistent with the present invention may be implemented;
FIG. 2 is a simplified block diagram of the Hub of FIG. 1 ;
FIG. 3 is a simplified block diagram of a PEA of FIG. 1 ;
FIG. 4 is a block diagram of a software architecture of a Hub or PEA in an implementation consistent with the present invention;
FIG. 5 is an exemplary diagram of communication processing by the layers of the software architecture of FIG. 4 ;
FIG. 6 is an exemplary diagram of a data block architecture within the DCL of the Hub and PEA in an implementation consistent with the present invention;
FIG. 7A is a detailed diagram of an exemplary stream usage plan in an implementation consistent with the present invention;
FIG. 7B is a detailed diagram of an exemplary stream usage assignment in an implementation consistent with the present invention;
FIG. 8 is an exemplary diagram of a time division multiple access (TDMA) frame structure in an implementation consistent with the present invention;
FIG. 9A is a detailed diagram of activity within the Hub and PEA according to a TDMA plan consistent with the present invention;
FIG. 9B is a flowchart of the Hub activity of FIG. 9A ;
FIG. 9C is a flowchart of the PEA activity of FIG. 9A ;
FIGS. 10A and 10B are high-level diagrams of states that the Hub and PEA traverse during a data transfer in an implementation consistent with the present invention;
FIGS. 11 and 12 are flowcharts of Hub and PEA attachment processing, respectively, consistent with the present invention; and
FIG. 13 is a flowchart of PEA detachment and reattachment processing consistent with the present invention.
DETAILED DESCRIPTION
The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims.
Systems and methods consistent with the present invention provide a wireless personal area network that permits a host device to communicate with a varying number of peripheral devices with minimal interference from neighboring networks. The host device uses tokens to manage all of the communication in the network, and automatic attachment and detachment mechanisms to communicate with the peripheral devices.
Network Overview
A Personal Area Network (PAN) is a local network that interconnects computers with devices (e.g., peripherals, sensors, actuators) within their immediate proximity. These devices may be located nearby and may frequently or occasionally come within range and go out of range of the computer. Some devices may be embedded within an infrastructure (e.g., a building or vehicle) so that they can become part of a PAN as needed.
A PAN, in an implementation consistent with the present invention, has low power consumption and small size, supports wireless communication without line-of-sight limitations, supports communication among networks of multiple devices (over 100 devices), and tolerates interference from other PAN systems operating within the vicinity. A PAN can also be easily integrated into a broad range of simple and complex devices, is low in cost, and is capable of being used worldwide.
FIG. 1 is a diagram of a PAN 100 consistent with the present invention. The PAN 100 includes a single Hub device 110 surrounded by multiple Personal Electronic Accessory (PEA) devices 120 configured in a star topology. Other topologies may also be possible. Each device is identified by a Media Access (MAC) address.
The Hub 110 orchestrates all communication in the PAN 100 , which consists of communication between the Hub 110 and one or more PEA(s) 120 . The Hub 110 manages the timing of the network, allocates available bandwidth among the currently attached PEAs 120 participating in the PAN 100 , and supports the attachment, detachment, and reattachment of PEAs 120 to and from the PAN 100 .
The Hub 110 may be a stationary device or may reside in some sort of wearable computer, such as a simple pager-like device, that may move from peripheral to peripheral. The Hub 110 could, however, include other devices.
The PEAs 120 may vary dramatically in terms of their complexity. A very simple PEA might include a movement sensor having an accelerometer, an 8-bit microcontroller, and a PAN interface. An intermediate PEA might include a bar code scanner and its microcontroller. More complex PEAs might include PDAs, cellular telephones, or even desktop PCs and workstations. The PEAs may include stationary devices located near the Hub and/or portable devices that move to and away from the Hub.
The Hub 110 and PEAs 120 communicate using multiplexed communication over a predefined set of streams. Logically, a stream is a one-way communications link between one PEA 120 and its Hub 110 . Each stream has a predetermined size and direction. The Hub 110 uses stream numbers to identify communication channels for specific functions (e.g., data and control).
The Hub 110 uses MAC addresses to identify itself and the PEAs 120 . The Hub 110 uses its own MAC address to broadcast to all PEAs 120 . The Hub 110 might also use MAC addresses to identify virtual PEAs within any one physical PEA 120 . The Hub 110 combines a MAC address and a stream number into a token, which it broadcasts to the PEAs 120 to control communication through the network 100 . The PEA 120 responds to the Hub 110 if it identifies its own MAC address or the Hub MAC address in the token and if the stream number in the token is active for the MAC address of the PEA 120 .
Exemplary Hub Device
FIG. 2 is a simplified block diagram of the Hub 110 of FIG. 1 . The Hub 110 may be a battery-powered device that includes Hub host 210 , digital control logic 220 , radio frequency (RF) transceiver 230 , and an antenna 240 .
Hub host 210 may include anything from a simple microcontroller to a high performance microprocessor. The digital control logic (DCL) 220 may include a controller that maintains timing and coordinates the operations of the Hub host 210 and the RF transceiver 230 . The DCL 220 is specifically designed to minimize power consumption, cost, and size of the Hub 110 . Its design centers around a time-division multiple access (TDMA)-based network access protocol that exploits the short range nature of the PAN 100 . The Hub host 210 causes the DCL 220 to initialize the network 100 , send tokens and messages, and receive messages. Responses from the DCL 220 feed incoming messages to the Hub host 210 .
The RF transceiver 230 includes a conventional RF transceiver that transmits and receives information via the antenna 240 . The RF transceiver 230 may alternatively include separate transmitter and receiver devices controlled by the DCL 220 . The antenna 240 includes a conventional antenna for transmitting and receiving information over the network.
While FIG. 2 shows the exemplary Hub 110 as consisting of three separate elements, these elements may be physically implemented in one or more integrated circuits. For example, the Hub host 210 and the DCL 220 , the DCL 220 and the RF transceiver 230 , or the Hub host 210 , the DCL 220 , and the RF transceiver 230 may be implemented as a single integrated circuit or separate integrated circuits. Moreover, one skilled in the art will recognize that the Hub 110 may include additional elements that aid in the sending, receiving, and processing of data.
Exemplary PEA Device
FIG. 3 is a simplified block diagram of the PEA 120 . The PEA 120 may be a battery-powered device that includes a PEA host 310 , DCL 320 , RF transceiver 330 , and an antenna 340 . The PEA host 310 may include a sensor that responds to information from a user, an actuator that provides output to the user, a combination of a sensor and an actuator, or more complex circuitry, as described above.
The DCL 320 may include a controller that coordinates the operations of the PEA host 310 and the RF transceiver 330 . The DCL 320 sequences the operations necessary in establishing synchronization with the Hub 110 , in data communications, in coupling received information from the RF transceiver 330 to the PEA host 310 , and in transmitting data from the PEA host 310 back to the Hub 110 through the RF transceiver 330 .
The RF transceiver 330 includes a conventional RF transceiver that transmits and receives information via the antenna 340 . The RF transceiver 330 may alternatively include separate transmitter and receiver devices controlled by the DCL 320 . The antenna 340 includes a conventional antenna for transmitting and receiving information over the network.
While FIG. 3 shows the exemplary PEA 120 as consisting of three separate elements, these elements may be physically implemented in one or more integrated circuits. For example, the PEA host 310 and the DCL 320 , the DCL 320 and the RF transceiver 330 , or the PEA host 310 , the DCL 320 , and the RF transceiver 330 may be implemented as a single integrated circuit or separate integrated circuits. Moreover, one skilled in the art will recognize that the PEA 120 may include additional elements that aid in the sending, receiving, and processing of data.
Exemplary Software Architecture
FIG. 4 is an exemplary diagram of a software architecture 400 of the Hub 110 in an implementation consistent with the present invention. The software architecture 400 in the PEA 120 has a similar structure. The software architecture 400 includes several distinct layers, each designed to serve a specific purpose, including: (1) application 410 , (2) link layer control (LLC) 420 , (3) network interface (NI) 430 , (4) link layer transport (LLT) 440 , (5) link layer driver (LLD) 450 , and (6) DCL hardware 460 . The layers have application programming interfaces (APIs) to facilitate communication with lower layers. The LLD 450 is the lowest layer of software. Each layer may communicate with the next higher layer via procedural upcalls that the higher layer registers with the lower layer.
The application 410 may include any application executing on the Hub 110 , such as a communication routine. The LLC 420 performs several miscellaneous tasks, such as initialization, attachment support, bandwidth control, and token planning. The LLC 420 orchestrates device initialization, including the initialization of the other layers in the software architecture 400 , upon power-up.
The LLC 420 provides attachment support by providing attachment opportunities for unattached PEAs to attach to the Hub 110 so that they can communicate, providing MAC address assignment, and initializing an NI 430 and the layers below it for communication with a PEA 120 . The LLC 420 provides bandwidth control through token planning. Through the use of tokens, the LLC 420 allocates bandwidth to permit one PEA 120 at a time to communicate with the Hub 110 .
The NI 430 acts on its own behalf, or for an application 410 layer above it, to deliver data to the LLT 440 beneath it. The LLT 440 provides an ordered, reliable “snippet” (i.e., a data block) delivery service for the NI 430 through the use of encoding (e.g., 16-64 bytes of data plus a cyclic redundancy check (CRC)) and snippet retransmission. The LLT 440 accepts snippets, in order, from the NI 430 and delivers them using encoded status blocks (e.g., up to 2 bytes of status information translated through Forward Error Correction (FEC) into 6 bytes) for acknowledgments (ACKs).
The LLD 450 is the lowest level of software in the software architecture 400 . The LLD 450 interacts with the DCL hardware 460 . The LLD 450 initializes and updates data transfers via the DCL hardware 460 as it delivers and receives data blocks for the LLT 440 , and processes hardware interrupts. The DCL hardware 460 is the hardware driven by the LLD 450 .
FIG. 5 is an exemplary diagram of communication processing by the layers of the software architecture 400 of FIG. 4 . In FIG. 5 , the exemplary communications involve the transmission of a snippet from one node to another. This example assumes that the sending node is the Hub 110 and the receiving node is a PEA 120 . Processing begins with the NI 430 of the Hub 110 deciding to send one or more bytes (but no more than will fit) in a snippet. The NI 430 exports the semantics that only one transaction is required to transmit these bytes to their destination (denoted by “(1)” in the figure). The NI 430 sends a unique identifier for the destination PEA 120 of the snippet to the LLT 440 . The LLT 440 maps the PEA identifier to the MAC address assigned to the PEA 120 by the Hub 110 .
The LLT 440 transmits the snippet across the network to the receiving device. To accomplish this, the LLT 440 adds header information (to indicate, for example, how many bytes in the snippet are padded bytes) and error checking information to the snippet, and employs reverse-direction status/acknowledgment messages and retransmissions. This is illustrated in FIG. 5 by the bidirectional arrow between the LLT 440 layers marked with “(n+m).” The number n of snippet transmissions and the number m of status transmissions in the reverse direction are mostly a function of the amount of noise in the wireless communication, which may be highly variable. The LLT 440 may also encrypt portions or all of the snippet using known encryption technology.
The LLT 440 uses the LLD 450 to provide a basic block and stream-oriented communications service, isolating the DCL 460 interface from the potentially complex processing required of the LLT 440 . The LLT 440 uses multiple stream numbers to differentiate snippet and status blocks so that the LLD 450 need not know which blocks contain what kind of content. The LLD 450 reads and writes the hardware DCL 460 to trigger the transmission and reception of data blocks. The PEA LLT 440 , through the PEA LLD 450 , instructs the PEA DCL 460 which MAC address or addresses to respond to, and which stream numbers to respond to for each MAC address. The Hub LLT 440 , through the Hub LLD 450 , instructs the Hub DCL 460 which MAC addresses and stream numbers to combine into tokens and transmit so that the correct PEA 120 will respond. The Hub DCL 460 sends and receives (frequently in a corrupted form) the data blocks across the RF network via the Hub RF transceiver 230 ( FIG. 2 ).
The Hub LLT 440 employs FEC for status, checksums and error checking for snippets, and performs retransmission control for both to ensure that each snippet is delivered reliably to its client (e.g., PEA LLT 440 ). The PEA LLT 440 delivers snippets in the same order that they were sent by the Hub NI 430 to the PEA NI 430 . The PEA NI 430 takes the one or more bytes sent in the snippets and delivers them in order to the higher-level application 410 , thereby completing the transmission.
Exemplary DCL Data Block Architecture
FIG. 6 is an exemplary diagram of a data block architecture 600 within the DCL of the Hub 110 and the PEA 120 . The data block 600 contains a MAC address 610 designating a receiving or sending PEA 120 , a stream number 620 for the communication, and a data buffer 630 which is full when sending and empty when receiving. As will be described later, the MAC address 610 and stream number 620 form the contents of a token 640 . When the LLD 450 reads from and writes to the hardware DCL 460 , the LLD 450 communicates the MAC address 610 and stream number 620 with the data buffer 630 . When a PEA 120 receives a data block, the DCL 460 places the MAC address 610 and stream number 620 contained in the preceding token 640 in the data block 600 to keep track of the different data flows.
Exemplary Stream Architecture
The LLD 450 provides a multi-stream data transfer service for the LLT 440 . While the LLT 440 is concerned with data snippets and status/acknowledgements, the LLD 450 is concerned with the size of data blocks and the direction of data transfers to and from the Hub 110 .
FIG. 7A is a detailed diagram of an exemplary stream usage plan 700 in an implementation consistent with the present invention. A single stream usage plan may be predefined and used by the Hub 110 and all PEAs 120 . The PEA 120 may have a different set of active streams for each MAC address it supports, and only responds to a token that specifies a MAC address of the PEA 120 and a stream that is active for that MAC address. In an implementation consistent with the present invention, every PEA 120 may support one or more active Hub-to-PEA streams associated with the Hub's MAC address.
The stream usage plan 700 includes several streams 710 - 740 , each having a predefined size and data transfer direction. The plan 700 may, of course, have more or fewer entries and may accommodate more than the two data block sizes shown in the figure. In the plan 700 , streams 0-2 ( 710 ) are used to transmit the contents of small data blocks from the PEA 120 to the Hub 110 . Streams 3-7 ( 720 ) are used to transmit the contents of larger data blocks from the PEA 120 to the Hub 110 . Streams 8-10 ( 730 ), on the other hand, are used to transmit the contents of small data blocks from the Hub 110 to the PEA 120 . Streams 11-15 ( 740 ) are used to transmit the contents of larger data blocks from the Hub 110 to the PEA 120 .
To avoid collisions, some of the streams are reserved for PEAs desiring to attach to the network and the rest are reserved for PEAs already attached to the network. With such an arrangement, a PEA 120 knows whether and what type of communication is scheduled by the Hub 110 based on a combination of the MAC address 610 and the stream number 620 .
FIG. 7B is a detailed diagram of an exemplary stream usage assignment by the LLT 440 in an implementation consistent with the present invention. The LLT 440 assigns different streams to different communication purposes, reserving the streams with small block size for status, and using the streams with larger block size for snippets. For example, the LLT 440 may use four streams (4-7 and 12-15) for the transmission of snippets in each direction, two for odd parity snippets and two for even parity snippets. In other implementations consistent with the present invention, the LLT 440 uses different numbers of streams of each parity and direction.
The use of more than one stream for the same snippet allows a snippet to be sent in more than one form. For example, the LLT 440 may send a snippet in its actual form through one stream and in a form with bytes complemented and in reverse order through the other stream. The alternating use of different transformations of a snippet more evenly distributes transmission errors among the bits of the snippet as they are received, and hence facilitates the reconstruction of a snippet from multiple corrupted received versions. The receiver always knows which form of the snippet was transmitted based on its stream number.
The LLT 440 partitions the streams into two disjoint subsets, one for use with Hub 110 assigned MAC addresses 750 and the other for use with attaching PEAs' self-selected MAC addresses (AMACs) 760 . Both the LLT 440 and the LLD 450 know the size and direction of each stream, but the LLT 450 is responsible for determining how the streams are used, how MAC numbers are assigned and used, and assuring that no two PEAs 120 respond to the same token (containing a MAC address and stream number) transmitted by the Hub 110 . One exception to this includes the Hub's use of its MAC address to broadcast its heartbeat 770 (described below) to all PEAs 120 .
Exemplary Communication
FIG. 8 is an exemplary diagram of a TDMA frame structure 800 of a TDMA plan consistent with the present invention. The TDMA frame 800 starts with a beacon 810 , and then alternates token broadcasts 820 and data transfers 830 . The Hub 110 broadcasts the beacon 810 at the start of each TDMA frame 800 . The PEAs 120 use the beacon 810 , which may contain a unique identifier of the Hub 110 , to synchronize to the Hub 110 .
Each token 640 ( FIG. 6 ) transmitted by the Hub 110 in a token broadcast 820 includes a MAC address 610 ( FIG. 6 ) and a stream number 620 for the data buffer 630 transfer that follows. The MAC address 610 and stream number 620 in the token 640 together specify a particular PEA 120 to transmit or receive data, or, in the case of the Hub's MAC address 610 , specify no, many, or all PEAs to receive data from the Hub 110 (depending on the stream number). The stream number 620 in the token 640 indicates the direction of the data transfer 830 (Hub 110 to PEA 120 or PEA 120 to Hub 110 ), the number of bytes to be transferred, and the data source (for the sender) and the appropriate empty data block (for the receiver).
The TDMA plan controls the maximum number of bytes that can be sent in a data transfer 830 . Not all of the permitted bytes need to be used in the data transfer 830 , however, so the Hub 110 may schedule a status block in the initial segment of a TDMA time interval that is large enough to send a snippet. The Hub 110 and PEA 120 treat any left over bytes as no-ops to mark time. Any PEA 120 not involved in the data transfer uses all of the data transfer 830 bytes to mark time while waiting for the next token 640 . The PEA 120 may also power down non-essential circuitry at this time to reduce power consumption.
FIG. 9A is an exemplary diagram of communication processing for transmitting a single data block from the Hub 110 to a PEA 120 according to the TDMA plan of FIG. 8 . FIGS. 9B and 9C are flowcharts of the Hub 110 and PEA 120 activities, respectively, of FIG. 9A . The reference numbers in FIG. 9A correspond to the flowchart steps of FIGS. 9B and 9C .
With regard to the Hub activity, the Hub 110 responds to a token command in the TDMA plan [step 911 ] ( FIG. 9B ) by determining the location of the next data block 600 to send or receive [step 912 ]. The Hub 110 reads the block's MAC address 610 and stream number 620 [step 913 ] and generates a token 640 from the MAC address and stream number using FEC [step 914 ]. The Hub 110 then waits for the time for sending a token 640 in the TDMA plan (i.e., a token broadcast 820 in FIG. 8 ) [step 915 ] and broadcasts the token 640 to the PEAs 120 [step 916 ]. If the stream number 620 in the token 640 is zero (i.e., a NO-DATA-TRANSFER token), no PEA 120 will respond and the Hub 110 waits for the next token command in the TDMA plan [step 911 ].
If the stream number 620 is non-zero, however, the Hub 110 determines the size and direction of the data transmission from the stream number 620 and waits for the time for sending the data in the TDMA plan (i.e., a data transfer 830 ) [step 917 ]. Later, when instructed to do so by the TDMA plan (i.e., after the PEA 120 identified by the MAC address 610 has had enough time to prepare), the Hub 110 transmits the contents of the data buffer 630 [step 918 ]. The Hub 110 then prepares for the next token command in the TDMA plan [step 919 ].
With regard to the PEA activity, the PEA 120 reaches a token command in the TDMA plan [step 921 ] ( FIG. 9C ). The PEA 120 then listens for the forward error-corrected token 640 , having a MAC address 610 and stream number 620 , transmitted by the Hub 110 [step 922 ]. The PEA 120 decodes the MAC address from the forward error-corrected token [step 923 ] and, if it is not the PEA's 120 MAC address, sleeps through the next data transfer 830 in the TDMA plan [step 924 ]. Otherwise, the PEA 120 also decodes the stream number 620 from the token 640 .
All PEAs 120 listen for the Hub heartbeat that the Hub 110 broadcasts with a token containing the Hub's MAC address 610 and the heartbeat stream 770 . During attachment (described in more detail below), the PEA 120 may have two additional active MAC addresses 610 , the one it selected for attachment and the one the Hub 110 assigned to the PEA 120 . The streams are partitioned between these three classes of MAC addresses 610 , so the PEA 120 may occasionally find that the token 640 contains a MAC address 610 that the PEA 120 supports, but that the stream number 620 in the token 640 is not one that the PEA 120 supports for this MAC address 610 . In this case, the PEA 120 sleeps through the next data transfer 830 in the TDMA plan [step 924 ].
Since the PEA 120 supports more than one MAC address 610 , the PEA 120 uses the MAC address 610 and the stream number 620 to identify a suitable empty data block [step 925 ]. The PEA 120 writes the MAC address 610 and stream number 620 it received in the token 640 from the Hub 110 into the data block [step 926 ]. The PEA 120 then determines the size and direction of the data transmission from the stream number 620 and waits for the transmission of the data buffer 630 contents from the Hub 110 during the next data transfer 830 in the TDMA plan [step 927 ]. The PEA 120 stores the data in the data block [step 928 ], and then prepares for the next token command in the TDMA plan [step 929 ].
FIGS. 9A-9C illustrate communication of a data block from the Hub 110 to a PEA 120 . When the PEA 120 transfers a data block to the Hub 110 , similar steps occur except that the Hub 110 first determines the next data block to receive (with its MAC address 610 and stream number 620 ) and the transmission of the data buffer 630 contents occurs in the opposite direction. The Hub 110 needs to arrange in advance for receiving data from PEAs 120 by populating the MAC address 610 and stream number 620 into data blocks with empty data buffers 630 , because the Hub 110 generates the tokens for receiving data as well as for transmitting data.
FIGS. 10A and 10B are high-level diagrams of the states that the Hub 110 and PEA 120 LLT 440 ( FIG. 4 ) go through during a data transfer in an implementation consistent with the present invention. FIG. 10A illustrates states of a Hub-to-PEA transfer and FIG. 10B illustrates states of a PEA-to-Hub transfer.
During the Hub-to-PEA transfer ( FIG. 10A ), the Hub 110 cycles through four states: fill, send even parity, fill, and send odd parity. The fill states indicate when the NI 430 ( FIG. 4 ) may fill a data snippet. The even and odd send states indicate when the Hub 110 sends even numbered and odd numbered snippets to the PEA 120 . The PEA 120 cycles through two states: want even and want odd. The two states indicate the PEA's 120 desire for data, with ‘want even’ indicating that the last snippet successfully received had odd parity. The PEA 120 communicates its current state to the Hub 110 via its status messages (i.e., the state changes serve as ACKs). The Hub 110 waits for a state change in the PEA 120 before it transitions to its next fill state.
During the PEA-to-Hub transfer ( FIG. 10B ), the Hub 110 cycles through six states: wait/listen for PEA-ready-to-send-even status, read even, send ACK and listen for status, wait/listen for PEA-ready-to-send-odd status, read odd, and send ACK and listen for status. According to this transfer, the PEA 120 cannot transmit data until the Hub 110 requests data, which it will only do if it sees from the PEA's status that the PEA 120 has the next data block ready.
The four listen for status states schedule when the Hub 110 asks to receive a status message from the PEA 120 . The two ‘send ACK and listen for status’ states occur after successful receipt of a data block by the Hub 110 , and in these two states the Hub 110 schedules both the sending of Hub status to the PEA 120 and receipt of the PEA status. The PEA status informs the Hub 110 when the PEA 120 has successfully received the Hub 110 status and has transitioned to the next ‘fill’ state.
Once the PEA 120 has prepared its next snippet, it changes its status to ‘have even’ or ‘have odd’ as appropriate. When the Hub 110 detects that the PEA 120 has advanced to the fill state or to ‘have even/odd,’ it stops scheduling the sending of Hub status (ACK) to the PEA 120 . If the Hub 110 detects that the PEA 120 is in the ‘fill’ state, it transitions to the following ‘listen for status’ state. If the PEA 120 has already prepared a new snippet for transmission by the time the Hub 110 learns that its ACK was understood by the PEA 120 , the Hub 110 skips the ‘listen for status’ state and moves immediately to the next appropriate ‘read even/odd’ state. In this state, the Hub 110 receives the snippet from the PEA 120 .
The PEA 120 cycles through four states: fill, have even, fill, and have odd (i.e., the same four states the Hub 110 cycles through when sending snippets). The fill states indicate when the NI 430 ( FIG. 4 ) can fill a data snippet. During the fill states, the PEA 110 sets its status to ‘have nothing to send.’ The PEA 120 does not transition its status to ‘have even’ or ‘have odd’ until the next snippet is filled and ready to send to the Hub 110 . These two status states indicate the parity of the snippet that the PEA 120 is ready to send to the Hub 110 . When the Hub 110 receives a status of ‘have even’ or ‘have odd’ and the last snippet it successfully received had the opposite parity, it schedules the receipt of data, which it thereafter acknowledges with a change of status that it sends to the PEA 120 .
Exemplary Attachment Processing
The Hub 110 communicates with only attached PEAs 120 that have an assigned MAC address 610 . An unattached PEA can attach to the Hub 110 when the Hub 110 gives it an opportunity to do so. Periodically, the Hub 110 schedules attachment opportunities for unattached PEAs that wish to attach to the Hub 110 , using a small set of attach MAC (AMAC) addresses and a small set of streams dedicated to this purpose.
After selecting one of the designated AMAC addresses 610 at random to identify itself and preparing to send a small, possibly forward error-corrected, “attach-interest” message and a longer, possibly checksummed, “attach-request” message using this AMAC and the proper attach stream numbers 620 , the PEA 120 waits for the Hub 110 to successfully read the attach-interest and then the attach-request messages. Reading of a valid attach-interest message by the Hub 110 causes the Hub 110 believe that there is a PEA 120 ready to send the longer (and hence more likely corrupted) attach-request.
Once a valid attach-interest is received, the Hub 110 schedules frequent receipt of the attach-request until it determines the contents of the attach-request, either by receiving the block intact with a valid checksum or by reconstructing the sent attach-request from two or more received instances of the sent attach-request. The Hub 110 then assigns a MAC address to the PEA 120 , sending the address to the PEA 120 using its AMAC address.
The Hub 110 confirms receipt of the MAC address by scheduling the reading of a small, possibly forward error-corrected, attach-confirmation from the PEA 120 at its new MAC address 610 . The Hub 110 follows this by sending a small, possibly forward error-corrected, confirmation to the PEA 120 at its MAC address so that the PEA 120 knows it is attached. The PEA 120 returns a final small, possibly forward error-corrected, confirmation acknowledgement to the Hub 110 so that the Hub 110 , which is in control of all scheduled activity, has full knowledge of the state of the PEA 120 . This MAC address remains assigned to that PEA 120 for the duration of the time that the PEA 120 is attached.
FIGS. 11 and 12 are flowcharts of Hub and PEA attachment processing, respectively, consistent with the present invention. When the Hub 110 establishes the network, its logic initializes the attachment process and, as long as the Hub 110 continues to function, periodically performs attachment processing. The Hub 110 periodically broadcasts heartbeats containing a Hub identifier (selecting a new heartbeat identifier value each time it reboots) and an indicator of the range of AMACs that can be selected from for the following attach opportunity [step 1110 ] ( FIG. 11 ). The Hub 110 schedules an attach-interest via a token that schedules a small PEA-to-Hub transmission for each of the designated AMACs, so unattached PEAs may request attachment.
Each attaching PEA 120 selects a new AMAC at random from the indicated range when it hears the heartbeat. Because the Hub 110 may receive a garbled transmission whenever more than one PEA 120 transmits, the Hub 110 occasionally indicates a large AMAC range (especially after rebooting) so that at least one of a number of PEAs 120 may select a unique AMAC 610 and become attached. When no PEAs 120 have attached for some period of time, however, the Hub 110 may select a small range of AMACs 610 to reduce attachment overhead, assuming that PEAs 120 will arrive in its vicinity in at most small groups. The Hub 110 then listens for a valid attach-interest from an unattached PEA [step 1120 ]. The attach-interest is a PEA-to-Hub message having the AMAC address 610 selected by the unattached PEA 120 .
Upon receiving a valid attach interest, the Hub 110 schedules a PEA-to-Hub attach-request token with the PEA's AMAC 610 and reads the PEA's attach-request [step 1130 ]. Due to the low-power wireless environment of the PAN 100 , the attach-request transmission may take more than one attempt and hence may require scheduling the PEA-to-Hub attach-request token more than once. When the Hub 110 successfully receives the attach-request from the PEA, it assigns a MAC address to the PEA [step 1140 ]. In some cases, the Hub 110 chooses the MAC address from the set of AMAC addresses.
The Hub 110 sends the new MAC address 610 in an attach-assignment message to the now-identified PEA 120 , still using the PEA's AMAC address 610 and a stream number 620 reserved for this purpose. The Hub 110 schedules and listens for an attach-confirmation response from the PEA 120 using the newly assigned MAC address 610 [step 1150 ].
Upon receiving the confirmation from the PEA 120 , the Hub 110 sends its own confirmation, acknowledging that the PEA 120 has switched to its new MAC, to the PEA 120 and waits for a final acknowledgment from the PEA 120 [step 1160 ]. The Hub 110 continues to send the confirmation until it receives the acknowledgment from the PEA 120 or until it times out. In each of the steps above, the Hub 110 counts the number of attempts it makes to send or receive, and aborts the attachment effort if a predefined maximum number of attempts is exceeded. Upon receiving the final acknowledgment, the Hub 110 stops sending its attach confirmation, informs its NI 430 ( FIG. 4 ) that the PEA 120 is attached, and begins exchanging both data and keep-alive messages (described below) with the PEA 120 .
When an unattached PEA 120 enters the network, its LLC 420 ( FIG. 4 ) instructs its LLT 440 to initialize attachment. Unlike the Hub 110 , the PEA 120 waits to be polled. The PEA 120 instructs its DCL 460 to activate and associate the heartbeat stream 770 ( FIG. 7B ) with the Hub's MAC address and waits for the heartbeat broadcast from the Hub 110 [step 1210 ] ( FIG. 12 ). The PEA 120 then selects a random AMAC address from the range indicated in the heartbeat to identify itself to the Hub 110 [step 1220 ]. The PEA 120 instructs its DCL 460 to send an attach-interest and an attach-request data block to the Hub 110 , and activate and associate the streams with its AMAC address [step 1230 ]. The PEA 120 tells its driver to activate and respond to the selected AMAC address for the attach-assignment stream.
The unattached PEA 120 then waits for an attach-assignment with an assigned MAC address from the Hub 110 [step 1240 ]. Upon receiving the attach-assignment, the PEA 120 finds its Hub-assigned MAC address and tells its driver to use this MAC address to send an attach-confirmation to the Hub 110 to acknowledge receipt of its new MAC address [step 1250 ], activate all attached-PEA streams for its new MAC address, and deactivate the streams associated with its AMAC address.
The PEA 120 waits for an attach confirmation from the Hub 110 using the new MAC address [step 1260 ] and, upon receiving it, sends a final acknowledgment to the Hub 110 [step 1270 ]. The PEA 120 then tells its NI 430 that it is attached.
The PEA 120 , if it hears another heartbeat from the Hub 110 before it completes attachment, discards any prior communication and begins its attachment processing over again with a new AMAC.
Exemplary Detachment and Reattachment Processing
The Hub 110 periodically informs all attached PEAs 120 that they are attached by sending them ‘keep-alive’ messages. The Hub 110 may send the messages at least as often as it transmits heartbeats. The Hub 110 may send individual small, possibly forward error-corrected, keep-alive messages to each attached PEA 120 when few PEAs 120 are attached, or may send larger, possibly forward error-corrected, keep-alive messages to groups of PEAs 120 .
Whenever the Hub 110 schedules tokens for PEA-to-Hub communications, it sets a counter to zero. The counter resets to zero each time the Hub 110 successfully receives a block (either uncorrupted or reconstructed) from the PEA 120 , and increments for unreadable blocks. If the counter exceeds a predefined threshold, the Hub 110 automatically detaches the PEA 120 without any negotiation with the PEA 120 . After this happens, the Hub 110 no longer schedules data or status transfers to or from the PEA 120 , and no longer sends it any keep-alive messages.
FIG. 13 is a flowchart of PEA detachment and reattachment processing consistent with the present invention. Each attached PEA 120 listens for Hub heartbeat and keep-alive messages [step 1310 ]. When the PEA 120 first attaches, and after receiving each keep-alive message, it resets its heartbeat counter to zero [step 1320 ]. Each time the PEA 120 hears a heartbeat, it increments the heartbeat counter [step 1330 ]. If the heartbeat counter exceeds a predefined threshold, the PEA 120 automatically assumes that the Hub 110 has detached it from the network 100 [step 1340 ]. After this happens, the PEA 120 attempts to reattach to the Hub 110 [step 1350 ], using attachment processing similar to that described with respect to FIGS. 11 and 12 .
If the Hub 110 had not actually detached the PEA 120 , then the attempt to reattach causes the Hub 110 to detach the PEA 120 so that the attempt to reattach can succeed. When the PEA 120 is out of range of the Hub 110 , it may not hear from the Hub 110 and, therefore, does not change state or increment its heartbeat counter. The PEA 120 has no way to determine whether the Hub 110 has detached it or how long the Hub 110 might wait before detaching it. When the PEA 120 comes back into range of the Hub 110 and hears the Hub heartbeat (and keep-alive if sent), the PEA 120 then determines whether it is attached and attempts to reattach if necessary.
CONCLUSION
Systems and methods consistent with the present invention provide a wireless personal area network that permit a host device to communicate with a varying number of peripheral devices with minimal power and minimal interference from neighboring networks by using a customized TDMA protocol. The host device uses tokens to facilitate the transmission of data blocks through the network.
The foregoing description of exemplary embodiments of the present invention provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The scope of the invention is defined by the claims and their equivalents. | A portable endpoint device comprises a first virtual device and a second virtual device integrated in a same single unit and configured such that the first virtual device and the second virtual device are configured to allow communication therewith as virtually different physical devices despite being integrated in the same single unit. In operation, the device is configured to receive a first signal from another endpoint device to indicate the availability of the another endpoint device for attachment; send, to the another endpoint device a second signal utilizing first scheduling-related information, the second signal including a first one of a plurality of identifiers for unique identification in association with the portable endpoint device; receive, from the another endpoint device a third signal that is sent in response to the second signal; and receive, from the another endpoint device data utilizing a second one of the identifiers for identification in association with the portable endpoint device. |
FIELD OF THE INVENTION
[0001] The invention pertains to efficiently condensing boil off gas for applications such as liquid natural gas terminals.
BACKGROUND OF THE INVENTION
[0002] Liquid natural gas (“LNG”) terminals continuously generate boil off gas (“BOG”). This BOG is generated primarily due to heat leak from the atmosphere through tank insulation, unloading and recirculation line insulation, and from pumping energy and gas displacement from LNG storage tanks during ship unloading.
[0003] It is relatively easy to condense BOG in a counter flow packed tower, that is, a packed bed type condenser. However, much more BOG is created during unloading operations than during normal send-out operations.
[0004] There can be difficulty in controlling pressure during transient stages of operations, such as beginning or ending ship unloading. For send-out operations to remain uninterrupted, it is important that BOG condenser pressure be maintained. Failure to do so can create interruptions in delivery, because LNG send out pumps may trip and interrupt send-out flow.
[0005] Conventional BOG condensers comprise a condenser stack (a packed section) on the top of the condenser and a surge drum at the bottom. The surge drum is intended to provide surge volume for the LNG send out pumps. LNG from the send out pumps is commonly divided into two flow streams. The first LNG flow stream enters the top of the packed bed and is flow controlled. This first LNG flow stream is used to condense BOG introduced into the condenser. The second LNG flow stream is either fed into the top of the bottom drum and is level controlled, or can be connected to the suction header of the LNG send out pumps.
[0006] In such conventional designs, a BOG unloading compressor feeds BOG into the condenser stack at the bottom of the packed bed, to be condensed in the packed bed by the first LNG flow stream. The bottom section must simultaneously serve as a surge vessel for the LNG send out pumps and maintain a liquid level. Thus, this design is sensitive to transitions in operating volume, such as a substantial increase in BOG volume during ship offloading. It is desirable to reduce such pressure fluctuations and thereby improve the reliability of the terminal during all phases of operation.
[0007] Accordingly, it is an object of the invention to provide a BOG condenser which can maintain an appropriate operating pressure in multiple operation phases.
[0008] It is another object of the invention to provide a BOG condenser which is pressure-controllable through transient phases of terminal operation.
SUMMARY OF THE INVENTION
[0009] The invention is a BOG condenser which comprises a vessel with a vertically split bed, allowing BOG to be condensed in a plurality of separated condensation zones. LNG bottom fluid level in the vessel can be maintained by an overflow seal, or alternatively by a level control valve. The vessel is vertically split by dividers which extend downward below the bottom fluid level in the vessel. Packing is inserted between the dividers, and between the outermost divider and the vessel inner wall, thus forming separate packing zones.
[0010] LNG is controllably allowed to flow into the top zone of the vessel, preferably above the level of the top of the packing. A plurality of LNG inlet lines are used, preferably arranged so that each LNG inlet line provides LNG flow to a single packing zone. A plurality of control valves on the LNG inlet lines allows a controller to separately control LNG flow to each packing zone.
[0011] Similarly, BOG is controllably allowed to flow into the bottom of each packing zone, preferably below the level of the bottom of the packing. As mentioned above, the dividers preferably extend below the level of the LNG bottom fluid, thereby preventing gaseous communication between the BOG inlets. In other words, the packing zones are functionally separated from each other, thereby allowing BOG flow in each packing zone to be individually controlled. As with the LNG inlet lines, a plurality of control valves on the BOG inlet lines allows a controller to separately control BOG flow to each packing zone.
[0012] A controller measures total flow ratios of LNG and BOG into the vessel, as well as the pressure in a line from the top of the condenser, and controls flow through the LNG inlets and the BOG inlets via their respective control valves to control the overall flow to the various packing zones. Thus, the controller can insure that the vessel is maintained within desired pressure and temperature ranges throughout a variety of BOG pressure and flow conditions. In the preferred embodiment, the vessel will maintain pressures in the range of 50 to 105 psia and temperatures in the range of −215 to −256° F.
[0013] During normal operations, the BOG condenser of this invention may operate using only one packing zone, to provide only the specifically needed surface area to accomplish the needed heat and mass transfer. Under increased BOG flow rates, the controller may be programmed to allow flow through one or more additional packing zone, so that the needed surface area is provided to avoid pressure fluctuations.
[0014] The number of dividers and the volumes of and amount and type of packing in the several packing zones are matters of engineering choice and appropriateness for the design requirements of the BOG condenser. As those of skill in the art will recognize, the relative sizes and capacities of the packing zones may be altered to accommodate the expected variations in BOG flow and pressure at a particular location.
BRIEF DESCRIPTION OF THE DRAWING
[0015] FIG. 1 is a cross-sectioned schematic representation of a side view of one embodiment of the invention.
[0016] FIG. 1A is a cross-sectioned schematic representation of a top view of one embodiment of the invention.
DETAILED DESCRIPTION
[0017] Referring to FIGS. 1 and 1 A, a schematic representation of an embodiment of the invention and depicting its process is shown. A BOG condenser 10 comprises a vessel 12 and interior dividers 14 within the vessel 12 . In the example shown, the dividers 14 are cylindrical and coaxial, resulting in cylindrical packing zone 16 and annular packing zones 18 and 20 . Packing 22 , 24 , and 26 is positioned within the packing zones 16 , 18 , and 20 respectively, and may be sized appropriately for the pressure and flow rates at which each individual packing zone is desired to operate. Packing 22 , 24 , and 26 thus divides each of packing zones 16 , 18 , and 20 into a respective upper section 17 and lower section 19 . Those of skill in the art will recognize that the number of packing zones used and their relative volumes are a matter of engineering choice appropriate to the installation.
[0018] LNG bottom fluid 30 in vessel 12 maintains a LNG fluid level 28 controlled by overflow seal 34 or other appropriate level control. Overflow seal 34 may be in fluid communication with LNG outlet 36 . Alternatively, those of skill in the art will recognize that a separate vessel (not shown) can be provided below the BOG condenser for hold up. Drain valve 32 allows vessel 12 to be completely drained when out of service.
[0019] LNG fluid level 28 is above the bottom of dividers 14 , thereby providing functional isolation between each packing zone so that BOG fed into each packing zone by BOG inlets 70 , 72 , and 74 cannot escape from one packing zone to another. In other words, there is no direct gaseous flow path between the lower sections 19 of the respective packing zones. BOG can only flow upward through the packing in its respective packing zone, to be substantially condensed by the LNG flowing downward.
[0020] As those of skill in the art will recognize, other means than the LNG bottom fluid level 18 may be used to provide a gas seal at the bottom of the lower sections 19 of the packing zones, without departing from the spirit of the invention. However, the recited arrangement simultaneously provides a gas seal and efficient recovery of condensed BOG.
[0021] BOG enters via BOG inlet 40 , and divides into a plurality of BOG inlets 70 , 72 , and 74 , preferably corresponding to the number of packing zones ( 16 , 18 , and 20 in the example shown). Similarly, LNG enters via LNG inlet 42 , and divides into a plurality of LNG inlets 56 , 58 , and 60 . The amount of LNG provided via LNG inlets 56 , 58 , and 60 is only the amount needed to condense BOG. The remainder of the LNG supply is directed through LNG inlet 38 .
[0022] Thus, BOG is fed into the lower sections 19 of the packing zones, and LNG is fed into the upper sections 17 of the packing zones. A controller, such as programmable controller 44 is provided information regarding the flow rates of the inlet BOG and LNG via data lines 48 and 46 , respectively, as well as the pressure in the line 49 from the top of vessel 12 via data line 47 . Control valve 45 provides a controllable outlet to a flow path 53 , such as a vent (not shown).
[0023] Based on the BOG to LNG flow ratios and the pressure in the line 49 from the top of the vessel 12 , controller 44 controls LNG flow control valves 50 , 52 , and 54 via control lines 51 , and BOG flow control valves 64 , 66 , and 68 via control lines 62 . For example, one or more packing zones may be shut off completely, or allowed to flow at a less than full-flow rate. In this way, control of the overall vessel pressure is possible that will allow the BOG condenser to compensate for BOG pressure fluctuations encountered during various operations. As those of skill in the art will recognize, programmable controller 44 may be replaced by a non-programmable controller (not shown), or even with manual controls without departing from the spirit of the invention.
[0024] The above examples are included for demonstration purposes only and not as limitations on the scope of the invention. Other variations in the construction of the invention may be made without departing from the spirit of the invention, and those of skill in the art will recognize that these descriptions are provide by way of example only. | A boil off gas ("BOG") condenser for use in LNG handling facilities which provides compensation for transient pressure changes in BOG flow due to variations in operations. |
BACKGROUND OF THE INVENTION
This invention relates generally to metallic particles and films, and more particularly to methods for their production by linking the electron pumping features of certain biological systems, such as the photosynthetic machinery, with the reductive precipitation of metallic particles.
Photosynthesis is the biological process that converts electromagnetic energy into chemical energy through light and dark reactions. In green algae and higher plants, photosynthesis occurs in specialized organelles, called chloroplasts. The chloroplast is enclosed by a double membrane and contains thylakoids, consisting of stacked membrane disks (called grana) and unstacked membrane disks (called stroma). The thylakoid membrane contains two key photosynthetic components, photosystem I and photosystem II, designated PSI and PSII, respectively, as depicted schematically in FIG. 1. During photosynthesis, water is split into molecular oxygen, protons and electrons by PSII. Electrons derived from the splitting of water molecules are transported through a series of carriers to PSI where they are further energized by a light-induced photochemical charge separation and transported across the thylakoid membrane where they are used for the enzymatic reduction of NADP + to NADPH. This biological reaction is further utilized for chemical energy production, primarily in the form of ATP.
Ultrafine metallic particles, e.g., nanoparticles, are important precursors for use in the fabrication of advanced material structures, such as thin continuous films. Conventionally, metallic films have been deposited on substrates by methods such as chemical vapor deposition (CVD), sputtering, plating, and the like. Unfortunately, such methods do not generally offer a degree of control desired for the deposition of nanostructured materials, e.g., films having nanometer range thicknesses or grains. Therefore, a method which could drive the nucleation, growth and deposition of nanoparticles in a quantitative, rapid, and energy-efficient manner would be highly desirable for many applications, including materials processing, catalysis, separations, electronics, energy production processes, and environmental applications.
Despite the extensive investigation concerning the photosynthetic machinery, the use of photosynthesis-related principles for materials synthesis and processing has not been described. The present invention, by exploiting the electron pumping characteristics of the photosynthetic machinery for nanoparticle production and processing applications, provides improved methods and materials which overcome or at least reduce the effects of one or more of the aforementioned problems.
SUMMARY OF THE INVENTION
This invention broadly concerns methods for the controlled deposition of ultrafine metallic particles and thin films via biomolecular electronic mechanisms. In particular, the invention takes advantage of the electron-pumping characteristics of photosynthesis system I (PSI), and other biological systems having similar features, for photocatalytically reducing metal precursor chemicals into metallic nanostructured materials.
Therefore, according to one aspect of the invention, a metallic film is formed by providing a liquid suspension which is at least partly comprised of a plurality of photosystem I-containing units, metal precursors, and any other component necessary or desired for effecting the photochemical reaction on the PSI-containing unit, e.g., electron donor molecules. The liquid suspension is contacted with light, preferably in the form of intermittent flashes, under conditions effective for causing the controlled reductive precipitation of the metal precursors on the photosystem I-containing units to form photosystem I-metal complexes. Generally, the liquid suspension containing the photosystem I-metal complexes is provided above the surface of a solid or semisolid substrate, such as a surface comprised of gold, silicon, silica, alumina, zirconia, titania, or any of a variety of other materials. Thereafter, the liquid of the liquid suspension is removed, for example by applying heat and/or vacuum to evaporate the liquid. Upon removal of the liquid, a film is thereby formed on the surface of the substrate that is at least partly comprised of the metal from the photosystem I-metal complexes.
In another aspect of the invention, a plurality of PSI-containing units may be anchored or otherwise coated on a desired substrate prior to performing the photo-induced formation of the photosystem I-metal complexes. This PSI-coated substrate is then contacted with a solution containing a plurality of metal precursors, electron donor molecules and other desired components. The solution and the underlying PSI-coated substrate are thereafter contacted with light energy under conditions effective for causing the reductive precipitation of the metal precusor on the photosystem I-containing unit to form photosystem I-metal complexes that are spatially constrained along the surface of the substrate. Under appropriate reaction conditions, the metal particles on the PSI-containing units are controllably grown to a size at which metal particles on adjacent PSI-containing units above the substrate merge into a continuous metallic film.
In another aspect of the invention, metallic nanoparticles are provided by forming PSI-metal complexes in a suitable liquid suspension and thereafter separating the metal particles from the PSI-metal complexes. The means by which the metal particles are separated may include any suitable chemical, physical or mechanical treatment sufficient to remove the particles from the complexes without adversely affecting their chemical composition or structural integrity.
The methods of the present invention offer numerous advantages over other technologies, e.g., CVD, sputtering, electroless plating, MBE, etc., for the production of metallic particles, films, and other materials such as alloys and composites. First the methods allow for precisely controlled metal particle nucleation and growth for atomic-level deposition. The methods are energy-efficient and have no requirement for high temperature or pressure/vacuum systems, such as are required for other technologies. Moreover, the methods offer controllable deposition kinetics which may be varied through modulation of the light energy input level. Finally, the methods are environmentally benign and non-interfering, i.e, light is the controlling mechanism.
The nanosized particles of this invention, and the products derived therefrom, will support a broad range of applications, including energetics (e.g., as fuel in propellants), explosives, microelectronics, catalysis, powder metallurgy, coating and joining technologies, and others. For example, for catalysis/separations applications, reductions in metallic film thicknesses will reduce metal cost, allow higher hydrogen flux, enhance permselectivity, and improve membrane reactor efficiency. The membrane reactors have been used in energy generation and environmental application processes, such as the advanced power generation and environmental application processes, such as the advanced power generation systems-integrated gasification combined cycle (IGCC) systems.
In the petrochemical industry, important applications may include hydrogen separation and membrane reactions concerning hydrocarbon (such as propane and ethylbenzene) dehydrogenation and natural gas steam reforming (e.g., CH 4 +H z O→CO+3H 2 ), oxidative reforming of methane to syngas, and partial oxidation or oxidative coupling of methane into hydrogen and higher hydrocarbons. For these chemical reactions, palladium (Pd)-based membranes may be preferred in terms of temperature resistance and hydrogen permeability, however other metals, e.g., platinum and osmium, may also be used. In addition, metallic nanoparticle arrays of uniform particle size in the range of about 2.5-100 nm deposited over a large area oxide (1 cm 2 ) support offer promising alternatives to single crystal surface catalysts.
The methods of the invention also find use in a variety of applications involving electronic materials and devices, such as electronic circuit board fabrication, metallic (Pd) buffer layer preparation for superconducting RABiTS (Rolling-Assisted Biaxially Textured Substrate), and multilayer devices (such as hard disk reading head memory chip) based on GMR (Giant Magnetorresistance).
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawings in which:
FIG. 1 depicts schematically a simplified representation of light-induced electron transport through the photosynthetic machinery of the thylakoid membrane;
FIG. 2 illustrates the production of a light-induced PSI-metal complex in a liquid suspension which contains metal precursors, electron donors and PSI-containing units. The metal precursors in the suspension undergo reductive precipitation at the reducing end of PSI to form a metal particles, the sizes of which may be controlled by the amount of light provided; and
FIG. 3 illustrates one embodiment of the invention wherein PSI-containing units are coated/anchored on a suitable substrate. The PSI-coated substrate is contacted with a solution containing metal precursors and electron donor molecules, and light energy is applied under condition for forming the desired PSI-metal complexes. As the metal particles of the PSI-metal complexes grow larger in response to a continued application of light energy, the particles can merge by biomolecular "welding" to form a continuous metal film over the substrate.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
According to the present invention, metallic nanoparticles and films are produced by light-mediated reactions between the reducing end of a PSI-containing unit and metal precursor compounds. The reactions are generally carried out in a liquid suspension containing metal precursor compounds and electron donor molecules such that the photoelectrodeposition and nanoparticle growth is induced on the reducing end of PSI reaction centers by the controlled administration of light energy. For example, by using a pulsed light source, metal precipitation on the reducing end of PSI, and consequently the size of metal particles generated, can be controlled at the atomic level, e.g. by precise deposition of one metal atom at a time.
Metallic nanoparticles, or metallic particles, as the terms are used herein, refer to the those particles attainable by the methods of the invention. The size of the nanoparticles so produced are not strictly limited, and may range, for example, from less than 1 nm to greater than 1000 nm or more. However, certain advantages may be realized when the nanoparticles have diameters in the range of about 1 nm to 100 nm. Preferably, the nanoparticles will have diameters in the range of about 1 nm to 10 nm. The metallic nanoparticles may be separated from the PSI-containing units after they are produced or may be used while still coupled to the PSI-containing units, depending on the particular application.
The PSI-containing units used in accordance with the present invention will preferably be comprised of isolated thylakoids or PSI particles prepared, for example, from spinach chloroplasts. Methods for the isolation and preparation of thylakoids and PSI particles are well known in the art (see, for example, Boardman, 1971; Setif et al., 1980; Reeves and Hall, 1980). Of course other PSI-containing units or photoelectron pumping units may also be used. For example, the PSI-containing unit may be comprised of any of a variety of combinations of photosynthetic and/or other cellular or non-cellular components provided the PSI-containing unit contains the components necessary for effecting reductive precipitation of the desired metal precursor. The PSI-containing unit, as the phrase is used in the context of this invention, may include other electron pumping cellular machineries from plant or non-plant organisms. The skilled individual will appreciate that other biological photochromic units (such as PSII, bacterial light-sensitive proteins, bacteriorhodopsin, photocatalytic microorganisms, and algae) or a biotic photocatalytic unit such as TiO 2 and pigments (e.g., proflavine and rhodopsin), may be suitable since these systems also possess a mechanism for light-induced electron pumping. Moreover, one could also produce electron pumping systems using self-assembled-monolayers containing light sensitive organic dyes.
PSI is a protein-chlorophyll complex that is part of the photosynthetic machinery within the thylakoid membrane (see FIG. 1). It is ellipsoidal in shape and has dimensions of about 5 by 6 nanometers. The photosystem I reaction center/core antenna complex contains about 40 chlorophylls per photoactive reaction center pigment (P700). The chlorophyll molecules serve as antennae which absorb photons and transfer the photon energy to P700, where this energy is captured and utilized to drive photochemical reactions. In addition to the P700 and the antenna chlorophylls, the PSI complex contains a number of electron acceptors. An electron released from P700 is transferred to a terminal acceptor at the reducing end of PSI through intermediate acceptors, and the electron is transported across the thylakoid membrane.
Natural photosynthetic systems have been modified to contain colloidal metallic platinum at the reducing site of PSI in thylakoid membranes in order to make metallic catalyst systems (see, for example, Greenbaum, 1985; Greenbaum, 1988; Greenbaum, 1990; Lee et al., 1990; Lee et al., 1994). In these reactions, molecular hydrogen is synthesized through reduction of protons by a reaction that is catalyzed by the platinum colloidal particles adjacent to the reducing site of PSI on the stromal side of the thylakoid membrane. Platinization of PSI can be accomplished through either chemical precipitation (such as platinum precipitation by H 2 purging) or preferably by in-situ photochemical reduction of platinum chemical precursors into metallic platinum colloid. Both chemical and in-situ photogenic reductive precipitation of metal platinum occur in close proximity to the PSI reducing end, indicating that metal precursors (e.g., [Pt(Cl) 6 ] 2- ) have high affinity for the PSI reducing end (Greenbaum 1988; Lee et al., 1994). It has been shown that the platinization process does not impede the intrinsic photosynthetic activity, e.g., electron transport (Greenbaum, 1990; Lee et al., 1995), and that the properties of PSI reaction centers are stable under relatively long-term storage (Lee et al., 1995). Importantly, because hydrogen is synthesized during the photoreductive precipitation reactions described herein, hydrogen evolution can be used as a sensitive indicator of metal particle formation on PSI (Greenbaum, 1988).
A film, as the term is used herein, refers to a film or coating at least partly comprised of and/or made from the nanoparticles described herein. Typically, the film will be supported by a solid substrate, such as those comprised of metal or ceramic, e.g., gold, silicon, silica, titania, zirconia, and the like. For most applications, the films will have a thickness in the range of about 1 nm to 5000 nm. Because of the high degree of control offered by this invention, high quality films in the range of about 1 nm to 100 nm are preferably produced. The metallic films produced according to the invention may be formed as composites or alloys with other materials. Additionally, they may contain residual proteinaceous material as a result of the presence of PSI-containing units present during some film forming processes
In one embodiment of the present invention, a method is provided for producing films from metallic nanoparticles using liquid suspensions comprised of photosystem I-containing units, metal precursor compounds and electron donor compounds. Additional components may also be present in the liquid suspension, for example, organic monomers, depending on the requirements and/or preferences of a given application. The liquid suspension is contacted with light under conditions in which the metal precursor undergoes reductive precipitation at the reducing end of the PSI particle of the PSI-containing unit. As a result, metallic particles are provided in the form of photosystem I-metal complexes in the liquid suspension. The size of the metallic particles in the PSI-metal complexes is directly related to amount and intensity of light energy administered. Consequently, particles having desired dimensions may be controllably synthesized.
The PSI-metal complexes are provided above a solid substrate, typically by applying a volume of the suspension on the surface of the substrate. The substrate may be one upon which the liquid suspension was previously applied prior to formation of the PSI-metal complexes. Alternatively, the PSI-metal complexes may be formed in a separate liquid suspension vessel and the liquid suspension may be thereafter applied above the substrate surface. In one preferred approach, sol/gel techniques are used wherein the substrate is dipped directly into the liquid suspension containing the PSI-metal complexes or the liquid suspension containing the PSI-metal complexes is spin coated onto the substrate. Such methods may be preferred where a high degree of thickness control is desired. Substantially all of the liquid present in the liquid suspension is removed from the coated substrate, for example by air drying or by applying heat, vacuum, etc., to cause evaporation of the liquid. This provides on the surface of the substrate a film comprised primarily of PSI-metal complexes.
Films having a variety of structural features may be obtained by this approach. For example, microporous films may be produced by coating the substrate with a liquid suspension comprised of a mixture of PSI-metal complexes wherein the PSI-containing units are thylakoids. Alternatively, nanoporous films may be provided by using liquid suspension containing PSI-metal complexes wherein the PSI-containing units are isolated PSI particles. Thus, the size of the biological components present in the PSI-metal complexes will determine to some extent the size of the pores in the materials following removal of the biological components from the films, e.g., by sintering. In addition, dense nanophase films can be provided by coating on the substrate a solution containing substantially pure metallic nanoparticles which have been separated from the PSI-metal complexes.
According to another embodiment of the invention, metallic film fabrication can be achieved on an ordered layer of PSI-containing units anchored or otherwise coated on the surface of a substrate (such as gold, silicon, alumina, etc.). These PSI-coated substrates have been described (see, for example, Rutherford and Setif, 1990; Lee et al., 1996; and Lee et al., 1995). The types of interactions (e.g., covalent, electrostatic, etc.) between the PSI-containing units and the substrate are not critical provided they are substantially stable in the liquid suspensions in which the photoreactions will be performed and they do not preclude the availability of the reducing end of the PSI unit for reductive metal precipitation.
The PSI-coated substrate is contacted with a solution (or, alternatively, could be exposed to vapor) that contains the desired metal precursor compounds and electron donor molecules. Light exposure of the PSI-containing units on the substrate leads to the reductive precipitation of the metal, as described above. However, in this embodiment, metal particle formation is spatially constrained along the surface of the substrate where the PSI-containing units are anchored. By controlling the input of light energy and the number of light pulses, and therefore particle growth, a biomolecular "welding" effect may be achieved on the PSI-coated layer, in which adjacent metallic particles precipitated on the PSI-containing units grow sufficiently large and eventually coalesce into a continuous metal film. The size of metal particles and the thickness of the film that is formed can therefore be precisely controlled by exposing an appropriate amount of light energy on the photoreactor system. Of course, the light input required to form a film having a desired thickness will depend to some extent on the density of the PSI-containing units coated on the substrate prior to light-induced metal precipitation.
Although thick films may be produced according to these methods, thin films having nanometer range thicknesses, e.g., 1 to 10 nm, are preferably synthesized to take advantage of the precise deposition control offered by this invention. None of the traditional film-forming technology, such as CVD, PVD, sputtering, or epitaxial growth can provide a comparable level of control. Moreover, the films of this invention can be advantageously provided as patterned metal layers using conventional photolithographic techniques.
In another embodiment of the invention, a method is provided for the production of metallic nanoparticles. In this approach, desired PSI-metal complexes are formed as described in the above embodiments. However, the PSI-metal complexes are not applied to a substrate to effect film formation. Rather, after the light induced reductive precipitation reactions, the PSI-metal complexes are treated in a manner which allows for the separation of metallic particles from the PSI-containing units. This can be accomplished by any of a number of approaches. For example, the PSI-metal complexes could be treated with various surfactants, e.g., sodium dodecyl sulfate (SDS), or could be subjected to sufficient agitation, ultrasonication, etc., in order to disrupt the association between the metal particles and the PSI-units. Alternatively, the biological components present in the PSI-metal complexes could be solubilized with an organic solvent or degraded using enzymatic reactions, e.g., using nucleases, proteases, etc, to remove the metal particles provided the treatment does not unacceptably compromise the integrity of the particles. Upon dissociation of the metal particles from the PSI-units using an approach such as those described above, the metal particles can be readily separated by one or more density-based separation techniques.
The metal precursor compounds used in conjunction with this invention can include any of a variety of compounds capable of undergoing reductive precipitation to form a desired metallic species. The metal precursors will typically comprise ionic metal salts capable of accepting electrons from PSI such that upon transfer of one or more electrons, the metal precursors are reduced to a pure metal form. Suitable metal precursors for producing the metallic particles of the invention may include, without limitation, ionic salts of platinum, palladium, osmium, ruthenium, iridium, silver, copper, indium, nickel, iron and tin, such as chloride-derived, sulfate-derived and nitrate-derived salts of these and related metals. Particularly preferred metal precusors for use in the invention include hexachloroplatinate ([PtCl 6 ] 2- ), hexachloroosmiate ([OsCl 6 ] 2- ), and hexachloropalladinate ([PdCl 6 ] 2- ).
The electron donor molecules which are included in the liquid suspensions according to the invention should of course be compatible with the PSI electron pumping system that is employed. The electron donor in most applications will be water, however some organic molecules may be present in the liquid suspensions which serve as facilitators of the electron transport process. These may include, for example, EDTA, proflavin, methylviologen, and the like. The concentration of these facilitator molecules, when present, will typically be in the range of about 10 mM to 100 mM in the liquid suspension.
Essentially any light source may be used in accordance with the invention provided it can generate light in a visible portion of the solar emission spectrum. Typically, the wavelengths of light most effective for causing PSI electron pumping activity will be between about 400 and 700 nm. Although the light exposure of the PSI-containing units may be continuous, it will generally be preferred to use intermittent pulses/flashes of light given the level of control this provides over particle growth. Intermittent illumination with a pulsed flash light source (e.g., a stroboscopic flash lamp) can provide quantitative control of the deposition at the reducing sites of PSI, one metallic atom at a time. Numerous such light sources are available, such as the GenRad Model 1539A xenon flash lamp. Preferably, the flash lamps are coupled with a trigger generator, such as the Hewlett Packard Model 8011A. This device allows the frequency of the trigger pulses to be varied from 1 to 400 Hz, the range of frequencies over which the xenon flash lamps may be fired without degrading light output.
In addition to the nanoparticles and continuous thin films described above, metallic patterns of nanoscale resolution may be prepared on a substrate surface by coupling laser and/or electron beam lithography techniques with the methods of this invention. For example, a position-controllable laser beam could be used to provide precise deposition of metal particles and/or lines in essentially any desired pattern on the surface of a PSI-coated substrate.
If the substrate on which the deposition is performed is a ceramic, the invention can be readily adapted for the fabrication of various types of metal-ceramic membranes, e.g., (1) dense or porous metallic membranes that are supported on porous ceramic membranes; (2) metals deposited inside the pores of ceramic membranes; and (3) metals coated on solid particles that are partially sintered onto inorganic membranes.
The following example is provided to illustrate one embodiment of this invention. The techniques disclosed in the example which follows represent those projected by the inventors to function in the practice of the invention and thus can be considered to constitute an example of one mode for its practice. However, those skilled in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.
EXAMPLES
Photobiomolecular Deposition of a Platinum Film
Type C chloroplasts are isolated according to the method of Reeves and Hall (1980). In this preparation, the chloroplast envelope is osmotically ruptured, exposing the thylakoid membranes to the external aqueous medium. The thylakoids are suspended in Walkers assay medium and adjusted to a final chlorophyll concentration of about 3 mg. A solution of chloroplatinic acid neutralized to pH 7 is added in the dark to the thylakoid suspension to give a final concentration of 1 mM in the suspension (this value is not critical provided there is an excess of hexachloroplatinate ions to photosystem I reaction centers). The liquid suspension is illuminated with a xenon stroboscopic light source (GenRad Type 1539) set to be triggered by a pulse generator (Hewlett-Packard 8011A). The frequency of the flashing is 10 Hz and the duration is 3 μsec at half height. Pulsed light exposure of the suspension is performed for 90 minutes. Following the light treatment of the suspension to form the desired PSI-metal complexes, the suspension is spin coated on a silicon substrate at about 25° C. to provide the desired film. The PSI-film so produced will exhibit photocatalytic properties and vectorial electron transport, and will be useful, for example, as a photocatalyst.
The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. More specifically, it will be apparent that certain compounds that are chemically, structurally and/or functionally related to those disclosed herein may be substituted in the methods of this invention while the same or similar results would be achieved. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.
REFERENCES
Boardman, Methods Enzymol, 23:268, 1971.
Greenbaum, "Platinized chloroplasts: a novel photocatalytic material," Science, 230(4732):1373, 1985.
Greenbaum, "Interfacial photoreactions at the photosynthetic membrane interface: an upper limit for the number of platinum atoms required to form a hydrogen-evolving platinum metal catalyst," J. Phys. Chem., 92:4571, 1988.
Greenbaum, "Biomolecular electronics: observation of oriented photocurrents by entrapped platinized chloroplasts," Bioelectrochemistry and Bioenergetics, 21:171, 1989.
Greenbaum, "Vectorial photocurrents and photoconductivity in metalized chloroplasts," J. Phys. Chem., 94:6151, 1990.
Greenbaum, "Kinetic studies of interfacial photocurrents in platinized chloroplasts," J. Phys. Chem., 96:514, 1992.
Lee, Tevault, Blankinship, Collins, Greenbaum, "Photosynthetic water splitting: in-situ photoprecipitation of metallocatalysts for photoevolution of hydrogen and oxygen," Energy & Fuels, 8:770, 1994.
Lee, Lee, Warmack, Allison, Greenbaum, "Molecular electronics of a single photosystems I reaction center: studies with scanning tunneling microscopy and spectroscopy," Proc. Natl. Acad. Sci. USA, 92:1965, 1995.
Lee and Greenbaum, "Bioelectronics and biometallocatalysis for production of fuels and chemicals by photosynthetic water splitting," Appl. Biochem. Biotechnol., 51(52):295, 1995.
Lee, Lee, Greenbaum, "Platinization: a novel technique to anchor photosystem I reaction centers on a metal surface at biological temperature and pH," Biosensors & Bioelectronics, 11(4):375, 1996.
Reeves, S. G.; Hall, D. O., Methods Enzymol. 69: 85-94, 1980.
Rutherford and Setif, "Orientation of P700, the primary electron donor of photosystem I," Biochimica et Biophysica Acta, 1019:128, 1990.
Setif, Acker, Lagoutte, Duranton, Photosynth. Res., 1:17, 1980. | The method of the invention is based on the unique electron-carrying function of a photocatalytic unit such as the photosynthesis system I (PSI) reaction center of the protein-chlorophyll complex isolated from chloroplasts. The method employs a photo-biomolecular metal deposition technique for precisely controlled nucleation and growth of metallic clusters/particles, e.g., platinum, palladium, and their alloys, etc., as well as for thin-film formation above the surface of a solid substrate. The photochemically mediated technique offers numerous advantages over traditional deposition methods including quantitative atom deposition control, high energy efficiency, and mild operating condition requirements. |
FIELD OF THE INVENTION
The present invention is directed to an improvement in computing systems and in particular to improved database query execution where the query being executed includes filtering operations.
BACKGROUND OF THE INVENTION
In query processing systems, such as the relational database management system (RDBMS) DB2™, data values are extracted from stored images of the data for further processing by the query evaluation system. Typically, the data is structured as rows comprised of column values, said rows being grouped into contiguous storage blocks known as pages. A part of the task of query evaluation comprises the process of isolating successive rows and extracting a (possibly proper) subset of the columns of the row for subsequent query evaluation steps such as filtering, sorting, grouping, or joining.
Extracting column values from pages involves steps of identifying and locating in main memory the page containing the next needed row, locating the next needed row within the page, locating the needed column values within the needed row, and copying the needed column values to new locations in memory where they are made available for subsequent query evaluation steps. Typically, locating a page in memory requires determining whether the page is in main memory and, if so, determining where in memory the page is located. If the page is not in main memory, the page must be brought to main memory from secondary storage (typically from disk).
Additionally, in query evaluation systems supporting concurrent query executions, steps must be taken to stabilize the page to ensure that it remains at the same location in memory and to avoid concurrent read and updates to the page to preserve the logical integrity of the page contents. Subsequent to copying needed column data values to new locations, the page stabilization conditions must be released.
The steps of accessing data by locating a page, stabilizing the page, locating a row in the page, and releasing stabilization for each row to be processed by the query evaluation system can constitute a significant portion of the overall execution cost of a query.
Prior art query evaluation systems, such as RDBMSs, use different approaches to avoid repeatedly accessing rows in a page by following the potentially costly steps set out above. For example, where there are predicates in queries that are to be satisfied, it is possible to evaluate the predicates for located rows before retrieving the sets of column values of interest for the queries. Where a row does not meet the predicate condition, the next row (potentially on the same page in the data) may be accessed without requiring a renewed stabilization of the page. The existing location in the page is also known, which may reduce the cost of locating the next row.
This application of predicates to column values of a current row while the column values still lie with their row in the currently identified page is sometimes called search argument (or SARG) processing. This processing approach allows the system to continue to the next row on the same page without releasing page stabilization, re-identifying the location of the page in memory, and re-stabilizing the page whenever the SARG predicate(s) are not satisfied. Additionally, programmatic book keeping associated with transfer of control between page processing and query evaluation components of the query processing system can be avoided for rows which would soon be discarded subsequent to a predicate being evaluated using the copied column values.
Another prior art approach to reducing the need to restabilize the data page involves processing the needed columns of the current row directly from its page in the data and continuing directly to the next row on the page. Typical processing operations which can “consume” column values directly from the page include sorting (enter column values into the sorting data structure) or aggregation (include column values in the running results for SUM, AVG, MAX, etc.). This type of processing is sometimes referred to as “consuming pushdown”, because there is a ‘pushdown’ of a consuming operation into data access processing.
The above approaches, however, apply only where there is a predicate to be evaluated, or where there is a consuming operation carried out as part of the query execution. In query processing systems, such as RDBMSs, there are other types of queries that are potentially costly to execute and which are therefore not susceptible to the above approach. An example of such a query is a query having non-predicate and non-consuming operations but which filter data values.
It is therefore desirable to have a query processor which is able to execute a query including filtering in a manner that reduces the number of page stabilizations required to execute the query.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided an improved execution of database queries including filtering operations. According to another aspect of the present invention, there is provided a method for processing a database query resulting in an access plan, including a filtering criteria, in a database management system comprising a data manager, a set of data, a query manager, the method comprising the steps of:
the query manager calling the data manager to access query-specified data in the set of data, the data manager performing a callback to the query manager the query manager indicating to the data manager, in response to the callback, whether the query-specified data satisfies the filtering criteria, the data manager returning the query-specified data based on the response from the query manager to the callback.
According to another aspect of the present invention, there is provided the above method in which the set of data is stored on pages and the method further comprising the step of the data manager stabilizing the page on which the query-specified data is located prior to access said data, the method further comprising the step of maintaining the stabilization of the page during callback to the query manager.
According to another aspect of the present invention, there is provided the above method in which the database query comprises an SQL DISTINCT clause.
According to another aspect of the present invention, there is provided a program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform method steps for processing queries for a database, said method steps comprising the method steps of claim 1 , 2 or 3 .
According to another aspect of the present invention, there is provided a computer program product for a database management system comprising a data manager, a set of data, and a query manager for processing a database query resulting in an access plan, including a filtering criteria, the computer program product comprising a computer usable medium having computer readable code means embodied in said medium, comprising:
computer readable program code means for the query manager to call the data manager to access query-specified data in the set of data, computer readable program code means for the data manager to perform a callback to the query manager, computer readable program code means for the query manager to indicate to the data manager, in response to the callback, whether the query-specified data satisfies the filtering criteria, computer readable program code means for the data manager to return the query-specified data based on the response from the query manager to the callback.
According to another aspect of the present invention, there is provided the above computer program product, in which the set of data is stored on pages and in which the computer usable medium having computer readable code means embodied in said medium, further comprises:
computer readable program code means for the data manager to stabilize the page on which the query-specified data is located prior to accessing said data, and computer readable program code means for maintaining the stabilization of the page during callback to the query manager.
According to another aspect of the present invention, there is provided a query processing system comprising a data manager, a set of data, and a query manager for processing a database query resulting in an access plan, including a filtering criteria,
the query manager comprising means for calling the data manager to access query-specified data in the set of data, the data manager comprising means for performing a callback to the query manager the query manager comprising means for indicating to the data manager, in response to the callback, whether the query-specified data satisfies the filtering criteria, and the data manager comprising means for returning the query-specified data based on the response from the query manager to the callback.
According to another aspect of the present invention, there is provided the above query processing system, in which the set of data is stored on pages and data manager further comprises means for stabilizing the page on which the query-specified data is located prior to access said data, and means for maintaining the stabilization of the page during callback to the query manager.
According to another aspect of the present invention, there is provided a query processing system comprising a data manager for accessing data records located in pages in a set of stored data, the data manager stabilizing a page on which a data record is stored before accessing the record, the query processing system also comprising:
a query processor for processing a data access plan, the query processor calling the data manager and the query processing system indicating to the data manager where a query being processed includes a designated filtering operator, where the data manager receives the indication of a designated filtering operator, the data manager stabilizing a current data page containing the next located record in the set of stored data, the data manager applying the designated filtering operator to a next located record before releasing the stabilization of the current data page, the data manager locating a further set of records in the stabilized current data page to locate a one of the records matching the designated filtering operator.
According to another aspect of the present invention, there is provided the above query processing system, in which the data manager applies the designated filtering operator to the next located record by calling the query processor to carry out the filtering operation.
Advantages of the present invention include improved efficiency for the execution of database queries that include filtering operations.
BRIEF DESCRIPTION OF THE DRAWING
The preferred embodiment of the invention is shown in the drawing, wherein:
FIG. 1 is a flow chart illustrating the steps in query interpretation using the preferred embodiment of the invention.
In the drawing, the preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood that the description and drawing are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention.
DETAILED DESCRIPTION
FIG. 1 is a flow chart diagram illustrating steps in executing a query in accordance with the preferred embodiment of the invention. Query 10 represents a query to be executed to access data in a database. Compiler 12 compiles query 10 and generates an access plan for the query. Query processor 14 receives the access plan from compiler 12 . As required, query processor 14 calls data management system (DMS or data manager) 16 to obtain access to data 18 . In the preferred embodiment, records or rows of data are stored on pages in data 18 . Data management system 16 retrieves column values from data 18 and returns the values to query processor 14 . Processing is carried out by query processor 14 in accordance with the access plan created by compiler 12 and data is returned as result 20 which corresponds to query 10 as applied to data 18 .
In query processing systems that support concurrent access to data, the location and stabilization of a page containing data is a potentially expensive operation. Each time that data management system 16 stabilizes a page in data 18 , and locates (using a notional cursor, in the preferred embodiment) a position in the page in data 18 , there will be a resulting time cost added to the processing of the query.
Where a query includes a filtering operation, such as that carried out by the DISTINCT operator found in SQL, there may be significant calls from data management system 16 to data 18 to retrieve rows for filtering by query processor 14 . As explained above, repeated accessing of data 18 where pages are stabilized and then released on each access, incorporates potentially avoidable inefficiencies in the query processing.
In the system of the preferred embodiment, non-predicate filter processing may be carried out without the data management system 16 releasing the stabilization of the page in data 18 which is being read from. It is therefore possible to carry out non-predicate filtering directly on column values of a current row while the column values are “in place” in the stabilized and located row in the currently identified page.
The approach of the preferred embodiment is described with reference to the following Program Description Language (PDL) of processing a query including the keyword DISTINCT. The example is presented as showing execution first without, and then with, the execution steps of the preferred embodiment. The example uses the following query on table “employee” have column “name”:
SELECT DISTINCT name FROM employee;
In the following PDL fragments, query_processor corresponds to query processor 14 , and data_manager corresponds to data management system 16 as shown for the RDBMS of FIG. 1 . In the RDBMS query execution without the steps of the preferred embodiment, the access plan for the above query results in the following execution:
1. data_manager stabilizes the page containing the next record (row) in the employee table; 2. data_manager copies the name column from the row located by data_manager to query_processor buffers (buffer thisRec) 3. data_manager releases the page position of the page containing the returned record (unfix/unlatch) 4. query_processor applies any further processing, in this case the FILTER:
if no records seen yet, initialize oldRec, a query_processor buffer for one record: oldRec=thisRec else if oldRec !=thisRec, then this is a distinct record, allow the data to flow (back to the user) else (oldRec==thisRec), this is a nonDistinct record, do not allow the data to flow query_processor loop back to first step, drive data_manager to get the next record
In the above approach, the DISTINCT filtering operation is done after the page is released and each row is produced by data_manager to query_processor.
The query processing of the example query using the approach of the preferred embodiment results in the following access plan being implemented:
1. data_manager positions the cursor (fix/latch) on a row location in a page in the data; 2. data_manager calls back to query_processor to filter the row (without releasing the fix/latch on the row location in the page in data):
if no records seen yet, initialize oldRec, a query_processor buffer for one record: oldRec=thisRec (where thisRec is the data_manager buffer), return to data_manager that the record qualifies else if oldRec !=thisRec, then this is a distinct record, return to data_manager that the record qualifies else (oldRec==thisRec), then this is a nonDistinct record, return to data_manager that the record does not qualify
3. if the record qualifies (it is determined to be distinct), then data_manager copies the name column from data_manager to query_processor buffers and data_manager releases the row position in the page in data (unfix/unlatch), proceed to step 4;
else data_manager positions the cursor to the next row on the page and loop to step 2, above
4. query_processor applies any further processing to the query_processor buffers 5. query_processor loop back to drive data_manager to get the next record.
The above description for the simple SQL query including filtering (by the DISTINCT keyword) illustrates the improvement of the preferred embodiment. The data manager is able to keep the data page stabilized over multiple rows where the filtering specified by the DISTINCT keyword results in rows being skipped in the processing of the query.
The preferred embodiment provides better query processing performance in comparison with processing that requires repeated calls to data manager 16 , in FIG. 1 . This is because, in a manner similar to SARG and consuming pushdown (referred to above), filtering the record allows the system to continue to the next row on the same page without releasing page stabilization, re-identifying the location of the page in memory, and re-stabilizing the page whenever the filtering operations are not satisfied. Additionally, programmatic bookkeeping associated with transfer of control between page processing and query evaluation components of the query processing system can be avoided for rows which would soon be discarded subsequent to a predicate being evaluated using the copied column values.
A further basis for increased query processing performance with the preferred embodiment system is related to the current state of the art in the architecture of central processing units (CPUs) on which the preferred embodiment will be implemented. In such CPUs, resource utilization is increased by spatial and temporal locality of reference. When a CPU references data and/or instructions that are near to other data or instructions, both in time and space, then the CPU is able achieve improved performance. A fast (but relatively small) cache is found near or on the CPU in many current CPUs. This cache is intended to be filled when new data or instruction locations are referenced. Subsequent references to the same data or instructions, or to proximate data or instructions that were loaded in the cache as part of the caching method, are retrieved from the (fast) cache. Where the CPU carries out access in this manner using the cache, the CPU is able to process data and instructions more quickly than where there is access to instructions or data not resident in the cache.
The preferred embodiment system permits a looping process to be carried out over the rows contained in a page. This looping process improves utilization of CPUs by increasing the spatial and temporal locality of both instruction and data references and, thus, makes more effective use of instructions and data lodged in the processor memory caches.
The processing of queries using the preferred embodiment system can occur in conjunction with other pushdown approaches to query evaluation such as SARG, consuming and other filtering pushdowns. The filtering pushdown of the preferred embodiment does not preclude the data in a row located by data manager 16 and identified as being one of the rows successfully passing the defined filter also being subject to other predicate evaluation or consuming operations before being potentially returned to query processor 14 .
It will also be apparent from this description that the filtering that is subject to the system of the preferred embodiment may be carried out where an SQL query (query 10 in FIG. 1 ) does not explicitly contain a filtering operator (such as DISTINCT) but where compiler 12 generates an access plan that includes a filtering operator as a logically equivalent query to the query as originally written. For example, optimizer 12 may use DISTINCT in the access plan for the following query:
SELECT name FROM employee GROUP BY name;
The rewritten query is the example set out above. The query is logically equivalent but will be able to make use of the approach of the preferred embodiment if rewritten including an express filtering operator (DISTINCT, in this case).
Although a preferred embodiment of the present invention has been described here in detail, it will be appreciated by those skilled in the art, that variations may be made thereto. Such variations may be made without departing from the spirit of the invention or the scope of the appended claims. | A query processing system has a query processor and a data manager. The query processor calls the data manager to carry out data access for a query including a filtering operation. The data manager accesses the data in a set of data and before returning the data, initiates a callback to the query processor to determine if the located data meets the filtering criteria. Where the data does not satisfy the filtering criteria, the data manager seeks additional data in the set of data, without having to return the first located data to the query processor. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates, in a first of its aspects, to a method of and an apparatus for applying a coating to articles, eg an edible coating to food articles. The invention is particularly, but not exclusively, concerned with the application of edible coating materials which exhibit non-Newtonian behaviour, for example chocolate, to articles of confectionery and the like. The present invention also relates, in a second of its aspects, to an improved method of forming a curtain of material eg edible material which can be used to coat articles eg articles of food or which can be used in other ways in the formation of articles, eg articles of food.
2. Description of Related Art
It is well known to enrobe articles of food such as chocolate assortmnents, confectionery bars, biscuits, cookies and cakes with a layer of chocolate. This coating process is known as chocolate enrobing and is traditionally effected by moving the articles on a mesh-type conveyor belt through a curtain of liquid chocolate whose consistency is carefully controlled. However, it is difficult to achieve the desired coating because of the high viscosity. It is therefore common practice to subject the articles to a greater than needed coating, then controlling the amount of chocolate remaining on the articles by blowing by air from fans and using vibration to remove the excess.
Also, the temperature of chocolate cannot be increased so as to reduce its viscosity as it will lose its temper, causing problems of incorrect fat crystallisation which can deleteriously affect the appearance and/or eating quality of the chocolate. Thus, it is common for enrobing chocolate to have a higher fat content than standard chocolate used for making chocolate bars in order to reduce its viscosity. This has adverse cost implications.
In order to establish the curtain of chocolate, it is known to allow chocolate to pass under the action of gravity through an outlet slot in the bottom of a trough having inclined side walls leading to the slot. This type of apparatus has a relatively low throughput because of the high viscosity of the chocolate and the relatively low rate at which it can flow through the outlet slot. The common solution to this problem is to use a wider slot, which results in a thicker curtain which then requires removal of more excess from the articles. Because of the physical characteristics of the chocolate which passes through the slot, the curtain can “neck” to a substantial extent. In other words, the width of the chocolate curtain becomes substantially less than the length of the slot from which it issues. This means that the effective cover of the curtain over the width of the conveyor belt used to carry the articles through the curtain is reduced.
Another known form of apparatus for producing a chocolate curtain utilises a roller along which liquid chocolate is distributed and carried to a blade which causes the layer of chocolate on the roller to become detached and thereby establish the curtain. This can provide higher coating rates with a better control of curtain thickness, but difficulties still arise in coating.
With both of the above types of known apparatus, the amount of chocolate in the descending curtain is greatly in excess of that required to coat the articles. The excess drains through the mesh-type conveyor belt and needs to be recycled and its condition carefully controlled.
SUMMARY OF THE INVENTION
It is an object of a first aspect of the present invention to obviate or mitigate at least some of the above disadvantages.
In accordance with said first aspect of the present invention, there is provided a method of applying a coating to articles, comprising the steps of:
(i) providing a curtain of solidifiable liquid coating material;
(ii) effecting relevant movement between articles to be coated and the curtain so as to coat the articles with the solidifiable liquid coating material; and
(iii) subjecting the solidifiable liquid coating material to the action of at least one stream of gas under pressure whereby to modify the flow characteristics of the curtain.
Also in accordance with said first aspect of the present invention, there is provided apparatus for applying a coating to articles, comprising:
(i) supply means arranged to provide a curtain of solidifiable liquid coating material;
(ii) means for effecting relative movement between articles to be coated and the supply means whereby in use the articles are coated with the solidifiable liquid coating material in the curtain; and
(iii) means arranged to subject the solidifiable liquid coating material to the action of at least one stream of gas under pressure whereby to modify the flow characteristics of the curtain.
Preferably, the articles are articles of food and the coating material is an edible coating material.
In the case where the present invention is used in a coating apparatus of the type in which the coating material is caused to flow along a surface of the supply means (eg a trough) towards an outlet slot through which the coating material flows under the action of gravity to form the curtain, it is preferred for said at least one stream of gas to be introduced between the coating material and the surface of the supply means. In this way, a layer of gas can be introduced between the surface and the coating material as it flows towards the outlet slot. Preferably, in the case of a trough where the coating material flows over opposed surfaces towards the outlet slot, a layer of gas is introduced between the coating material and each of the opposed surfaces. This can not only substantially reduce the resistance to flow of the coating material over the surfaces, but can also reduce the viscosity of the coating material if it is of a type whose viscosity is reduced when subjected to shear.
It is particularly preferred to cause said at least one stream of gas under pressure to become attached to the surface of the supply means so as to assist in establishing the layer of the gas between the surface and the coating material. This may be achieved by positioning one or more gas-admission slots in such a way as to direct the gas against the surface of the supply means. The spacing between the outlet slot and the or each gas-admission slot depends upon the nature of the coating material and the geometry of the supply means, which may comprise a trough having V-shaped walls defining opposed surfaces which converge towards the outlet slot. If the or each gas-admission slot is disposed too close to the outlet slot, then the flow of gas through the outlet slot may actually restrict the flow of coating material therethrough. On the other hand, if the or each gas-admission slot is disposed too far away from the outlet slot, the coating material flowing over the surface may become re-attached to the surface of the supply means before it reaches the outlet slot.
In the case where the above-mentioned trough is employed, it is within the scope of the present invention to provide said at least one stream of gas under pressure at one or both convergent opposed surfaces of the trough leading to the outlet slot.
Said at least one stream of gas under pressure may be applied to the coating material after the curtain has been established in order to change the direction of the curtain and/or a physical property of the coating material forming the curtain. It is also within the scope of the present invention to subject the coating material to the action of at least one stream of gas both before and after the curtain has been established.
A curved surface may be provided adjacent to part of the curtain, and means may be provided for causing a stream of gas to flow over the curved surface by virtue of the Coanda effect and to use this to induce a change in the direction of travel of the curtain. In this way, it is possible to control the direction of flow of the curtain from any angle from vertical to substantially horizontal. This effect can be used whether or not the coating material is subjected to the action of at least one stream of gas under pressure before the curtain is established. In this regard, the curtain may be established by flow of the coating material through an outlet slot or by distributing the coating material over the length of a roller and causing it to be transported to a blade which removes the coating material from the roller and thereby establishes the curtain.
It is within the scope of the present invention to use one or more curtains of coating material to coat the articles and to control the direction of movement of these curtains simultaneously or independently in such a way as to ensure maximum coverage. For example, one of the curtains may be controlled so that its direction of movement is an acute angle (e.g. 45°) relative to the direction of relative movement between the articles and the curtain, whilst the other curtain can be controlled so that its direction of movement is at an obtuse angle (e.g. 135°) with respect to said direction of relative movement. In this way, coating of upstream and downstream ends of the articles may be facilitated.
In certain embodiments, the control of the pressure of the stream of gas can be employed to control the speed of descent of the curtain. Thus, by controlling the rate of descent of the curtain and the rate of relative movement between the articles and the curtain, a variety of different effects can be achieved. For example, if the rate of descent of the curtain is matched with the rate of relative movement, then a smooth coating can be achieved. If the rate of curtain descent is greater than the rate of relative movement, then a surface patterning effect can be achieved by the resultant folding of the applied curtain onto the articles. On the other hand, if the rate of descent is less than the rate of relative movement, a degree of stretching of the coating material as it becomes attached to the articles may be achievable with resultant thinning of the layer of coating material, applied to the articles. The effects achieved will also depend upon the physical properties of the coating material.
The present invention is applicable to the use of non-Newtonian liquids such as chocolate or Newtonian liquids such as caramel as coating materials.
In the case of chocolate (or other non-Newtonian liquid, a liquid whose viscosity reduces when subjected to shear), a very high degree of control is achievable because the stream of gas under pressure can be caused to contact the surface of the chocolate in such a way as to reduce its viscosity by application of a shear force. This has the particular advantage that the chocolate flows much more easily but then rapidly thickens once the shear force has been removed. The application of the stream of gas under pressure to the chocolate before the curtain has been established can enable the previously mentioned necking problem to be mitigated and can also enable a much higher throughput to be achieved for a given size of coating apparatus. Because of the viscosity reduction achieved, it is possible to coat with a much higher viscosity chocolate than has heretofore been considered possible. For example, it is possible to coat with relatively viscous tempered chocolate, rather than having to coat with a chocolate composition having an increased fat content and subsequently lowered tempered viscosity in order to establish and maintain the desired liquid curtain. The need to effect air blowing and/or vibration on the coated articles may be obviated or mitigated. The present invention permits a curtain of even thickness to be achieved and may also enable a thinner curtain to be produced than has heretofore been possible.
Conveniently, the gas is air. The temperature of the gas may be substantially the same as that of the solidifiable liquid coating material. This is particularly advantageous in the case where the material is liquid chocolate.
It will be appreciated that the present invention in its first aspect involves the control of a curtain of solidifiable liquid coating material for the purpose of coating or enrobing articles. However, it will be appreciated that similar techniques can be employed for controlling a curtain of a solidifiable liquid material for use in the production of other articles. For instance, the curtain can be controlled for the purpose of enabling a layer of the material to be deposited into a mould or moulds (e.g. to produce shells of solidified material which can then be used to contain filling material), or onto a conveyor for solidification as a layer thereon which can be subsequently cut to size or otherwise shaped. The fact that the curtain can be very accurately controlled in terms of the thickness of the curtain and/or its angle/speed of descent means that a close control over the thickness and/or texture of the deposit can be obtained which can be difficult to achieve with standard confectionery shell technology.
Thus, in its second aspect, the present invention resides in a method of controlling a curtain of a solidifiable liquid composition comprising the steps of:
(i) providing a curtain of solidifiable liquid material; and
(ii) before, during and/or after step (i), subjecting the solidifiable liquid material to the action of at least one stream of gas under pressure whereby to modify the characteristics of the curtain.
Also in accordance with said second aspect of the present invention, there is provided apparatus for controlling curtain of a solidifiable liquid composition comprising:
(i) supply means arranged to provide a curtain of solidifiable liquid coating material; and
(ii) means arranged to subject the solidifiable liquid coating material to the action of at least one stream of gas under pressure whereby to modify the characteristics of the curtain.
The method and apparatus may further include provision for (a) depositing the modified curtain of solidifiable liquid composition to form a layer in a mould or on a surface, and (b) solidifying the deposited composition.
The solidifiable liquid composition is preferably an edible composition.
Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of one embodiment of an apparatus according to the present invention, where, for ease of demonstration, only one longitudinal trough surface is shown with an air supply, FIG. 2 is a side view of a trough forming part of the apparatus of FIG. 1, and FIG. 3 is a schematic view of a second embodiment of apparatus according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIGS. 1 and 2 of the drawings, the apparatus illustrated therein is for enrobing confectionery bars with a layer of chocolate. The apparatus comprises a mesh-type conveyer belt 10 carrying confectionery bars 12 to be coated horizontally from right to left as viewed in FIG. 1. A liquid chocolate supply trough 14 is spaced above the conveyor 10 and comprises V-shaped walls 14 a and 14 b leading to a downwardly opening outlet slot 14 c . The trough 14 contains liquid chocolate 16 which is to be used for coating the confectionery bars 12 to form coated confectionery bars 18 .
The trough 14 contains an additional wall 14 d which is inclined at an acute angle relative to the wall 14 b and which terminates about 10 mm above the outlet slot 14 c which, in this embodiment, has a width of about 2 mm. The walls 14 b and 14 d together define a downwardly convergent plenum chamber 20 terminating in an air-admission slot 22 . The slot 22 has a width of 0.2 mm and extends for the whole length of the outlet slot 14 c , and is disposed about 10 mm above the outlet slot 14 c of the trough 14 . The plenum chamber 20 is connected with a source of pressurized air. Although not shown in the drawings, the wall 14 a is likewise provided with an additional wall defining an identical air-admission slot like slot 22 .
Disposed below the conveyor 10 is a tank 24 which also contains liquid chocolate 16 . A pump (not shown) serves to pump the liquid chocolate 16 from the tank 24 to the trough 14 via pipework 28 .
In use, the conveyor belt 10 is operated to move the confectionery bars 12 in a path which carries them under the outlet slot 14 c of the trough 14 . The chocolate 16 in the trough 14 is typically maintained at a temperature in the range of 28 to 31° C. and travels through the slot 14 c under the action of gravity so as to produce a curtain 30 of liquid chocolate through which the confectionery bars 12 pass. The curtain 30 extends perpendicularly across the conveyor belt 10 which carries a plurality of rows of the confectionery bars 12 , although only one row of bars 12 is illustrated in the drawings. The resultant coated bars 18 are carried by the conveyor 10 and excess chocolate drips through the holes in the screen conveyor 10 and back into the tank 24 for recirculation.
During this time, air under pressure is supplied to the plenum chamber 20 so that it is ejected through the air-admission slot 22 so as to become attached to that portion of the wall 14 b which lies between the slots 22 and 14 c . The result of this is that a layer of air is inserted between the chocolate 16 passing towards the outlet slot 14 c and the wall 14 b immediately upstream of the slot 14 c . The same occurs at the wall 14 a . This substantially reduces the friction between the chocolate and the walls. Additionally, the pressurised air exerts a shear force on the adjacent surface of the chocolate, thus reducing the viscosity of the chocolate in the region of the outlet slot 14 c . This improves the flowability of the chocolate so that it substantially increases the flow rate through the slot and also mitigates the necking problem whereby the width of the curtain 30 , i.e. the dimension perpendicular to the plane of the drawing, can be maintained substantially the same as the length of the slot 14 c.
In one experiment, it was found that no less than a 70% increase in the flow rate through the slot 14 c could be achieved using an air supply pressure of 2 psig, as compared to the situation where no air is supplied through the gas-admission slot 22 . Although, substantially improved results could be achieved with air pressures as low as 0.5 psig and up to about 3 psig. It will be understood that the shear effect is produced because the air is moving at a greater rate than the chocolate with which it is in contact.
The above-described method enables improved control to be achieved, which can lead to the following advantages:
(a)lighter chocolate coatings,
(b) more precise coating with less excess deposit,
(c) less variation in deposit across the conveyor belt,
(d) faster enrobing speeds,
(e) lower proportion of chocolate to be recycled,
(f) less build-up of chocolate on the edges of the bars, leading to better edge definition,
(g) selective production of textured or plain coatings by adjustment of air pressure and conveyor belt speed.
(h) avoidance of the need to use enrobing chocolate (which has a high fat content to decrease its viscosity when liquid), thereby enabling the use of regular or even lower fat chocolate.
Referring now to FIG. 3 of the drawings, there is illustrated an apparatus also in accordance with the present invention for altering the direction of descent of chocolate curtain 30 . The chocolate curtain 30 may be one which has been produced as described hereinabove with reference to FIGS. 1 and 2. Alternatively, it may be a conventionally produced chocolate curtain which has been formed without introduction of an air-stream into trough 14 . As a further alternative, it may be a conventionally produced curtain formed by distributing a layer of liquid chocolate onto the surface of a roller and then detaching the layer from the roller by means of a blade.
In the apparatus of FIG. 3, there is provided a cylindrical plenum chamber 40 which is horizontally disposed to one side of the curtain 30 above the conveyer 10 and which extends for greater than the full width of the curtain 30 . The plenum chamber 40 may conveniently be mounted on the trough 14 so that it can be positioned close to the outlet 14 c . The plenum chamber 40 has a pressurised air inlet 42 and a row of upwardly directed air outlets 44 extending over the length of the plenum chamber 40 . An angled cap 46 is secured to the outer periphery of the plenum chamber 40 along a longitudinal side edge thereof which is remote from the curtain 30 . The opposite longitudinal side edge of the strip 46 is spaced from the peripheral surface of the plenum chamber 40 so as to define an air-exit slot 48 . The slot 48 has a width of typically about 0.2 mm. The plenum chamber 40 can be moved laterally horizontally relative to the curtain 30 so as to enable the gap between it and the curtain 30 to be adjusted. Likewise, the plenum chamber 40 can be turned about its longitudinal axis to enable the position of the slot 48 relative to the curtain 30 to be adjusted.
In use, air is supplied through the inlet 42 into the plenum chamber 40 from whence it issues through the outlets 44 and thence through the outlet slot 48 . It is thus caused to adhere to the curved peripheral surface of the plenum chamber 40 by virtue of the Coanda effect whereby it follows the external periphery of the plenum chamber 40 for a considerable distance. The effect of this curved flow of air is to draw the curtain 30 towards the plenum chamber 40 , thus altering the angle of descent of the curtain 30 . The angle of descent can be varied by varying the pressure of the air and/or by varying the positioning of the slot 48 relative to the curtain 30 .
In FIG. 3, the plenum chamber 40 is shown on the downstream side of the curtain 30 relative to the conveying direction of the confectionery bars 12 through the curtain 30 . Thus, the effect is to incline the direction of descent of the curtain 30 at an acute angle relative to the direction of movement of the confectionery bars 12 . This can enable improved effects to be achieved. It is possible to “lay” the curtain 30 of chocolate gently onto the surfaces of the bars 12 by appropriately matching the rate of descent of the curtain 30 to the speed and movement of the bars 12 . It is also considered that, because of the angling of the curtain 30 , it will be possible to improve coating of the leading ends of the confectionery bars. 12 .
However, it will be appreciated that it is possible to locate the plenum chamber 40 on the opposite side of the curtain 30 , ie on the upstream side thereof so as to cause the direction of descent of the curtain 30 to extend at an obtuse angle relative to the conveying direction of the confectionery bars 12 . In this way, it is considered that an improved coating of the trailing ends of the confectionery bars 12 may be achievable. Also, further control over the effects produced can be achieved by altering the conveyor rate relative to the rate of descent of the curtain 30 .
If desired, the confectionery bars 12 may be taken through more than one curtain 30 with the curtains being disposed of the same or different angles depending upon the effects required.
If desired, the confectionery bars may be passed through the curtain twice, the first time for the purpose of effecting a main coating operation and a second time for the purpose of ensuring that the coated bar is of the specified weight.
The curtain of chocolate (or another solidifiable liquid material) produced as described with reference to either or both of the illustrated embodiments may, instead of being used to enrobe articles such as confectionery bars, be used to form a layer of controlled properties (eg thickness) into moulds as an alternative to conventional depositing technology, followed by cooling to solidify the layer. Such a technique can be used to form shells for subsequent filling with a filling material. Alternatively, the curtain may be laid onto a conveyor to form a controlled layer thereon which is subsequently solidified and cut to size to the desired shape. | A coating such as liquid milk chocolate is applied to articles such as confectionery bars. The bars are conveyed by conveyor under a curtain of liquid chocolate issuing through an outlet slot in a trough. A layer of air is caused to flow through the outlet slot in the trough so as to modify the flow characteristics of the curtain. The layer of air permits a curtain of even thickness to be achieved. |
BACKGROUND OF THE INVENTION
It is generally known that conventional primary and secondary electric cells and batteries are subject to serious limitation on their use where substantial power is required, for example, as a power source for automobiles or for the propulsion of marine craft such as submarines. Widely used lead-acid batteries of the automobile industry are sturdy and generally dependable but have power/weight ratios which are far too low for the substantial power requirements for propulsion. This is also true of zinc type batteries and other commercially available electric cells. In general, the problem is to achieve energy density (watt hrs./lb.) and power density (watts/lb.) ratios in an electric cell or battery, which will be of such order as to meet the necessary power requirements.
Significant improvements in energy and power densities can be obtained by replacing the dense, high atomic weight metals, such as lead, with the less dense, low atomic weight alkali (lithium, sodium, potassium) and alkaline earth (magnesium, calcium) metals. These active metals react rapidly with water and thus a suitable non-aqueous solvent must be used. This often leads to a moderate saving in weight in that most nonaqueous solvents are less dense than water. Electric cells based on use of these materials, theoretically at least, enable substantially higher power/weight ratios to be obtained than in the more conventional batteries. By way of illustration, a complete lithium battery should be capable of achieving current and energy density ratios of the order of ten to 20 times that obtained with the conventional lead-acid battery. However, to date, and despite the obvious benefits to be obtained, no widely successful battery or electric cell has been developed wherein the lighter active metals are utilized. In general, these active metals are so reactive, particularly in the presence of moisture or atmospheric air (including nitrogen as well as oxygen), that they not only present hazards but also require expensive equipment and handling procedures for their use. By way of illustration, known lithium sulfur dioxide batteries are not only excessively expensive to fabricate (principally because of the problems in handling the metallic lithium), but also suffer the further difficulty that they are not designed to be rechargeable.
A further particular problem commonly encountered in electric cells and batteries, is a high degree of inherent internal resistance to current flow. This internal resistance leads to overheating and consequent ineffectiveness of the battery in use, as evidenced by the well know "burn out" under conditions of severe or continued loading.
Based on the foregoing, it will be apparent that the development of an improved battery cell and system is greatly to be desired, particularly as respects present limitations on maximum energy and power density ratios obtainable in current cells, the relatively low power/weight ratios available, and the difficulties associated with handling highly reactive but potentially highly successful electrode materials.
SUMMARY OF THE INVENTION
This invention relates generally to high energy battery cells of primary and secondary nature, and more particularly to an ambient temperature active metal cell wherein a dithionite salt of the active metal is used as a charging agent. It specifically relates to a secondary battery system utilizing an anhydrous solvent containing freshly dissolved lithium dithionite as part of the electrolyte.
In general, it is an object of the present invention to provide a new and improved primary or secondary cell based on use of active metal dithionites or mixtures thereof as a charging agent.
A further object of the present invention is to provide primary and secondary cells of the type described which achieve maximum power/weight ratios, through use of active metals of low atomic weight, such as lithium, sodium, potassium, magnesium and calcium.
A still further object of the invention is to provide new methods for both manufacturing and operating such improved primary and secondary cells, which enable effective use while avoiding the risks and difficulties of handling the specified, highly reactive metals.
A still further and specific object of the invention is to provide improved primary or secondary cells of the above character which make possible power/weight ratios sufficient to meet the power requirements for propulsion of primary vehicles and marine craft, such as automobiles, trucks, power boats and submarines.
As a brief statement of the invention, active metal cells of primary and secondary nature have been developed, making use of dithionite salts of an active metal as the charging agent, which are not only capable of use at ambient temperature but which also avoid the risks and difficulties normally encountered in the use of highly reactive metals. More specifically, the electrolyte in contact with the electrode is comprised of a suitable anhydrous solvent in which the active metal dithionite is dissolved. The electrolyte may additionally contain an additional source of ions in the form of a salt of the same active metal and also may be saturated with sulfur dioxide.
In a particular secondary battery system according to the invention, the electrolyte is circulated through a highly porous inert spacer between a negative electrode and a positive current gathering electrode, in a sealed and evacuated cell. The system is subjected to a charging current of an energy level sufficient to plate the active metal (e.g., lithium) on the negative electrode while releasing the sulfur dioxide at the positive electrode to further saturate the electrolyte. A continuous supply of electrolyte containing freshly dissolved dithionite is obtained through use of an auxiliary dissolving chamber in conjunction with solids separator (e.g., centrifugal separator), thus enabling use of anhydrous solvents in which the dithionite is only slightly soluble (e.g., acetonitrile, dimethyl sulfoxide). The performance of the battery system can be enhanced by use of a salt of the same active metal (e.g., lithium perchlorate) as part of the electrolyte, and as a source of additional active metal. In another system the slightly soluble active metal dithionite is physically held near or in a porous electrode so as to be readily available for consumption during charging. On discharge, the dithionite salt is reformed in or near the porous electrode for subsequent consumption during recharge.
Secondary cells as herein described (based on use of a dithionite salt of an active metal as the charging agent) are characterized by substantially increased power and energy density ratios, as compared to conventionally available secondary cells. By way of illustration, power/weight ratios of the order of ten times, or higher, than those obtained with the conventional lead-acid battery, are possible. Due to low internal resistance, the time required for recharging the battery will also be greatly reduced, for example, of the order of one-fifth the time required in an equivalent lead-acid cell. Besides extremely low internal resistance to current flow, other particular advantages of the cells include an unusually long shelf life, extremely good performance over a wide range of high and low temperatures, and a negligible depletion of the active dithionite, despite prolonged continuous use of the battery system.
The invention further contemplates the assembly and satisfactory use of primary cell systems, by charging cells containing active metal dithionites in nonaqueous electrolyte solutions, thus plating the active metals inside the cell. This eliminates the need to deal with the active metals as such. The final cell potential and discharge characteristics can be modified by replacing the charging electrolyte with other anhydrous electrolyte solutions, for example, electrolyte solutions employing or containing, specifically, sulfuryl chloride and thionyl chloride.
Other features and advantages of the invention will be apparent from the following description taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view in section and elevation of one embodiment of a secondary battery cell and system, in accordance with the present invention.
FIG. 2 is a view in section, along the line 2--2 of FIG. 1.
FIG. 3 is an enlarged sectional view along the line 3--3 of FIG. 2.
FIG. 4 is a greatly enlarged detail view of the indicated portion of FIG. 3.
FIG. 5 is an enlarged detail view along the line 5--5 of FIG. 1.
FIG. 6 is a view in section along the line 6--6 of FIG. 5.
PRACTICAL AND THEORETICAL CONSIDERATIONS
In order for a secondary battery to be rechargeable, both the anode and cathode reactions must be chemically reversible. In order to be a practical secondary cell, these reactions must also take place rapidly. It is known that the reduction of the active metal ions to the metals and subsequent oxidation of these metals, and particularly the lithium metal/lithium ion reaction, satisfies both of these conditions and, moreover, must be carried out in nonaqueous solvents which provide the further advantage of lower density solutions as compared to aqueous solutions. The metal ion reactions of other alkali metals and alkaline earth metals (viz., columns IA and IIA of the periodic table, herein "active metals") also satisfy the desired conditions.
Theoretical considerations related to an alkaline metal/sulfur dioxide battery suggest that SO 2 will be reduced to S 2 O 4 -- (dithionite) as the battery is discharged. It is further postulated that a satisfactory battery can be produced by dissolving an active metal dithionite (e.g., Li 2 S 2 O 4 ) in a nonaqueous solvent to produce the active metal and dithionite ions in solution (e.g., Li + and S 2 O 4 -- ). By passing a charging current through the solution containing such ions, the active metal (e.g., Li) will be deposited at one electrode and SO 2 gas will be released at the other. The advantage is a procedure for employing the highly reactive metals in solution without appreciable risk or difficulty in handling, while at the same time releasing sulfur dioxide gas to saturate the electrolyte.
To verify the foregoing concept with respect to the preferred active metal, lithium, lithium dithionite (Li 2 S 2 O 4 ) is prepared by the technique of ion exchange. Specifically, a column of cation exchange resin in the hydrogen ion (H + ) form is converted completely to the lithium ion (Li + ) form by passing a concentrated aqueous solution of lithium chloride through the column until the effluent is essentially neutral. The column is rinsed with deionized water until the excess lithium chloride is removed, as indicated by the absence of red lithium ion color in a flame test on the effluent. An aqueous solution of commercial sodium dithionite (Na 2 S 2 O 4 ), which has been deoxygenated by bubbling it with nitrogen or other inert gas, is then passed through the column. The effluent is collected in deoxygenated ethanol until a flame test on the effluent indicates the presence of sodium ion. The lithium dithionite is next precipitated from the ethanol, and is further washed with deoxygenated ethanol, filtered and vacuum dried. The lithium dithionite (Li 2 S 2 O 4 ) thus produced is relatively stable when dry and maintained at room temperature. However, it will rapidly decompose at temperatures near 200° C., and also reacts rapidly with oxygen when damp or in solution. The ultraviolet spectrum of the dithionite ion (S 2 O 4 -- ) is used to determine the presence and purity of the lithium metal dithionite. While the active metal dithionites are found to be appreciably soluble only in water, limited solubility (less than about 5%) can be achieved in such anhydrous solvents as acetonitrile and dimethylsulfoxide, among others.
To test the concept, a battery cell can be prepared wherein the electrolyte comprises a suitable nonaqueous solvent, (i.e., acetonitrile) and wherein the lithium dithionite is present as a slurry. In one satisfactory cell, a lithium salt is also present, preferably in the form of a saturated solution, and functions both as an electrolyte and as a source of additional lithium ion. As tests in aqueous solution show that the perchlorate and dithionite ions do not react, a saturated solution of lithium perchlorate in acetonitrile is satisfactorily utilized for such purpose, in the cells just described. Various conductive metals can be used for the negative electrode, including the noble metals (gold and silver), aluminum, copper and certain stainless steels. Conductive materials such as finely divided carbon and sintered aluminum can be used as the positive current gathering electrode. When current is passed through these cells, lithium is plated at the negative electrode, whereas sulfur dioxide gas is generated at the other electrode. When the charging current is discontinued, a constant stable voltage is observed. Such cells with electrode areas of about 15 square centimeters are capable of lighting 0.5 ampere bulbs for some time. When the bulb is disconnected, the voltage returns to its open circuit voltage. When the cell is completely discharged, it is found to be rechargeable many times. Although the cells can be alternatively operated with the addition of SO 2 gas, the behavior of the cells is essentially independent of the presence of the added SO 2 gas. However, when the lithium dithionite is omitted from the electrolyte, the cells fail to charge and produce current.
Successful use of the dithionite salt of an active metal as the charging agent in a secondary battery cell has led to the development of a full scale cell suitable for providing power to a primary propulsion system, for example, in a submarine or automobile. A specific embodiment of such cell, as used in a battery system, is described below.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to FIG. 1, reference numeral 10 generally represents a self-contained battery cell or unit in accordance with the present invention. This cell is cylindrical in configuration and includes an outer cylindrical shell 12 and two generally circular side plates 14 and 16. The side plates and outer shell are assembled in leaktight fashion upon an axial tube 18 which forms a central core for the unit. Assembly is accomplished by means of a pair of inner circular retaining washers 20, 22, which are held in place by suitable fastening means such as the bolt 24, and a pair of outer circular retaining flanges 26 and 28 which are held in place by suitable peripheral fastening means such as a series of bolts 30. In the assembled condition, the outer casing provides the interior annular chamber or space 32, defined by the side plates 14, 16, the outer shell 12 and the inner core 18. Suitable inert sealing members such as the O-rings 34 and 36 are positioned between the described casing members to insure that the annular space 32 is completely sealed as respects the exterior environment. As hereinafter described, the space 32 generally forms a battery chamber for an electric cell including active (negative) and current gathering (positive) electrodes.
Associated with the battery chamber or cell 10 and forming part of the electrochemical current producing system of the present invention is a circulatory chamber 40. This chamber can take any suitable form such as a cylindrical tank 42 and, as hereinafter described, generally functions as a reservoir for circulating anhydrous electrolyte containing undissolved or partially dissolved active metal dithionite. In the illustrated apparatus, the circulatory chamber 40 is in fluid communication with the battery cell 10 through conduits 44 and 46 connecting an outlet 48 from the battery chamber to an inlet 50 of the circulatory chamber, and through additional conduits 52 and 54 connecting an outlet 56 from the circulatory chamber to an inlet 58 in the battery chamber. As hereinafter described, circulation of electrolyte and dissolved charge transfer agent is accomplished by pump means 60 which generally functions to withdraw spent electrolyte from the battery chamber 10, to pass the same over a supply of solid dithionite 62 in the circulatory chamber 40, and to return electrolyte with freshly dissolved dithionite from the circulatory chamber to the battery chamber. Thus, referring specifically to FIG. 1, the pump 60 is positioned between the conduits 44, 46 joining the battery and circulating chambers, and functions to force circulating slurry of electrolyte and dithionite to a solids separation device 64, from which electrolyte and dissolved dithionite is charged to the battery chamber through the line 54. Undissolved solid dithionite separated in the device 64 is returned to the tank 42 through the line 66, pump 60 and conduit 46. While any satisfactory solids separation device may be employed (e.g., a continuous rotary filter), a centrifugal separator is most conveniently employed in that such apparatus is capable of acting through fluid flow to both "separate" and return undissolved dithionite to the circulatory chamber and to deliver to the battery cell a clear "filtrate" of electrolyte containing dissolved dithionite.
Referring to FIGS. 1 and 2, an electric battery cell 70 is positioned within the chamber 10 so as to substantially fill the interior annular space 32. In general terms, the battery cell 70 includes an elongate active electrode of conductive meterial (negative electrode) arranged in adjacent configuration to an elongate passive current gathering electrode (positive electrode) such that a passage is provided therebetween for the flow of electrolyte solution. In the illustrative apparatus, this passage between the elongate electrodes is maintained by positioning highly porous inert spacing means between the adjacent electrodes so as to insure a continuous unobstructed pathway for the circulating electrolyte and dissolved charge transfer agent. In more specific terms, the two electrodes and intermediate spacing means are arranged in an increasing spiral configuration advancing from an inner electrode terminal 72, adjacent to central core 18, to an outer electrode terminal 74, adjacent the outer shell 12. The inner terminal 72 is connected to the active (negative) electrode whereas the outer terminal 74 is connected to the current gathering (positive) electrode. In each instance, the terminal is mounted within a leaktight sealing device 76, to maintain the sealed integrity of the battery cell 10.
The construction and adjacent configuration of the electrodes in the spiral arrangement of the battery cell 70, is shown in the sectional view of FIG. 3. In general, the conductive material of the active electrode, represented at 80, may comprise any suitable conductive materials, for example, a bare metal such as copper, certain stainless steels, aluminum and the noble metals. An elongate strip of perforated copper or copper screen is particularly suited for the purpose. The current gathering electrode, represented at 82, may likewise comprise any suitable conductive material, for example, finely divided carbon or graphite, sintered aluminum or the like. In general, the electrode 82 is formed as an elongate strip which is generally contiguous with the electrode 80. As previously noted, an elongate highly porous inert non-conductive spacer, represented at 84, is positioned between the electrodes 80 and 82. The construction of the spacer 84 should be such that the electrolyte is free to circulate through the battery cell and between the spaced electrodes, to thereby reduce internal resistance to current flow (and the potential for heat gain). While various inert spacing materials can be employed, inert plastic materials in open lattice form (e.g., crossed strands of polypropylene or like alkali resistant fiber-forming plastics) are to be preferred. In general, the inert spacing means should be insoluble in the anhydrous organic solvents used in the electrolyte solution, and capable of being formed in highly porous configurations of the type described. In general, the porous spacing member 84 provides for free flow of electrolyte through the cell 70 in the battery chamber 10. To enhance this electrolyte flow, suitable flow pathways 85 can also be provided on the inner surfaces of the side plates 14 and 16 (See FIG. 2).
With particular reference to the electrolyte solution, an essential component is a substantially inert anhydrous organic solvent for the active metal dithionite employed as the charging agent. Preferably, the electrolyte solvent will also have good properties as a medium for promoting reactions involving ionization. The solvent should also be substantially inert with respect to the selected conductive materials employed as electrodes, viz., copper, aluminum, carbon etc. The anhydrous electrolyte liquid should function as a satisfactory solvent for the selected active metal dithionite salt employed as the charging agent and, also, for sulfur dioxide gas. With respect to the preferred active metal dithionite, lithium dithionite, particularly satisfactory anhydrous organic solvents include acetonitrile, dimethylsulfoxide, diethylformamide, and to a lesser extent, propylene carbonate, and isopropylamine, among others. Because of the generally low solubility of the active metal dithionites in anhydrous organic solvents, it is also advantageous and desirable to use an additional salt as an electrolyte to promote the conductivity of the solution. Generally, it has been found that certain inorganic salts of the same active metal as used in the dithionite are satisfactory for this purpose. Specifically, it has been found that the perchlorate salts of active metals will not react with the dithionite ions, based on testing and analysis in aqueous solution. Accordingly, in the case of the preferred lithium dithionite charging agent, lithium perchlorate has proved to be very satisfactory as an ionized component of the electrolyte. While active metal bromides, such as lithium bromide, are also satisfactory electrolytes, the use of such compounds is questionable because of the undesired production of bromine. On the other hand, battery cells have been satisfactorily employed employing lithium dithionite in a saturated solution of lithium bromide in acetonitrile.
In view of the foregoing considerations, it has been determined that a preferred electrolyte solution to be used with lithium dithionite is a mixture of acetonitrile with lithium perchlorate (viz., LiClO 4 ).
A particular advantage of the battery cell and system of the present invention is that current producing operations can be carried out at ambient temperatures, that is, without heating or cooling, and at atmospheric pressure.
It is possible in an atmospheric pressure cell to have the electrolyte essentially saturated with gaseous sulfur dioxide which may be added to the system at any convenient point, for example, in the inlet conduit 46 to the circulatory chamber or, as illustrated, directly to the tank 42 through the valved conduit 86. The presence of sulfur dioxide in the electrolyte solution may also be beneficial in that the gas may assist in the removal of any free oxygen or water by reaction therewith, to thereby avoid undesired reactions with the active metal or dithionite ions.
The start up and operation of the battery system illustrated in FIGS. 1 and 2 will now be described. Initially, desired quantities of dried crystalline active metal dithionite (prepared in the manner herein described) together with dry crystalline active metal perchlorate are placed in the circulatory chamber 40, as at 62. Valving in the circulatory system, represented at 43, 47 and 55 (FIG. 1) is then opened to permit the entire system to be subjected to the purging effects of a vacuum. Specifically, a vacuum is pulled on the reservoir chamber 40 by means of a suitable vacuum pump 90, operating through the lines 92 and 94. During such operation, the valve 96 in the electrolyte solvent supply line 98 is closed, whereas the valves 93 and 95 are open. The battery system comprising the battery chamber 10 and circulatory chamber 40 are then purged in several cycles involving the pulling of an appropriate vacuum (i.e., 40 microns) with the vacuum pump 90, and alternatively introducing dry inert gas (viz., argon or nitrogen) through the valve line 98 with assistance of the pump 60. These alternative pump and purge cycles (represented by the arrows 100, 102) serve to free the circulatory system of oxygen or water vapor such as might react with the active metal dithionite. The anhydrous organic electrolyte solvent is then introduced to the vacuum outlet (through line 98 and valve 96) to the reservoir chamber 40, where it mixes with the dry chemicals in the bottom of the reservoir. Simultaneously, the organic solvent can be saturated with sulfur dioxide to insure removal of any possible remaining oxygen or water vapor.
Assuming that the dry chemicals 62 include the selected active metal dithionite together with the same active metal perchlorate, the perchlorate totally dissolves in the entering solvent to form a saturated solution. However, the active metal dithionite, being only partially soluble, will remain substantially undissolved at the bottom of the reservoir chamber, with the portions of the undissolved dithionite forming a slurry with the entering solvent. In this "filling" operation, the solvent pump 104 is operated siumltaneously with the circulatory pump 60 to distribute electrolyte solution throughout the circulatory system including the battery cell 10. During such operation, undissolved dithionite circulating as a slurry with the electrolyte will be removed from the circulating liquid in the centrigugal separator 64, and returned through the line 62 to the bottom of the reservoir chamber. When the system is completely filled, the valve 96 can be closed so that the electrolyte circulates between the battery cell 10 and reservoir chamber 40 in a more or less steady state. However, sulfur dioxide gas can be continuously metered to the system at a controlled rate, under the control of the valve 106. At this stage, the battery cell 10 is in an inert discharge state, with electrolyte solution being continuously circulated through the porous pathway between the electrodes 80 and 82, provided by the inert strands of the spacing member 84 (see arrows 110 in FIGS. 3 and 4).
At this point, the battery cell is subjected to a charging current capable of supplying the energy level required to plate the active metal onto the negative electrode (i.e., the bare metal conductor 80), while simultaneously further saturating the circulating electrolyte with sulfur dioxide released from the oxidation of the dithionite ion, at the positive electrode 82. As particularly illustrated in the enlarged detail view of FIG. 4, the active metal is deposited as a layer 120 on the bare metal conductors 80. Because of the very low internal resistance to current flow in the pathway between the electrodes 80 and 82, the plating of the active metal ion continues even though there is a very low proportion of the available dithionite material in the solution in the circulating electrolyte. By way of illustration, the electrolyte may be saturated with dithionite at less than a 5% solution, say in a 1% solution, as respects the circulating organic solvent. However, due to the continuous circulation of freshly dissolved dithionite solution through the separator 64, and into the battery cell 10, a continuous supply of alkaline metal ion is available for plating on the negative electrode 80. In this operation, it will be appreciated that the active metal plated onto the conductor 80 itself becomes the conductive layer so that the active metal ion will continue to plate onto the conductor and build up in the free space available between the strands of the inert spacer 84. Because the plating reaction takes place at the constant ambient temperature, and in the presence of the circulating medium, there is very little energy loss due to internal resistance of the battery cell, and consequently negligible heat gain even at relatively high loading.
The discharge state of the described battery cell and system is best described with respect to a particular battery cell construction based on use of lithium dithionite as the charging agent, acetonitrile as the anhydrous organic solvent, and lithium perchlorate as a dissolved electrolyte. Thus, a particular battery cell 10, designed to fit within a sealed exterior opening (cylindrical) of a submarine hull may have dimensions of the order of 20 inches in diameter and 71/2 to 8 inches in thickness. The active (negative) electrode is an elongate ribbon of copper screening or perforated metal, 78 feet long, 5 inches wide and approximately 0.08 inches thick. The passive current gathering (positive) electrode is likewise formed as an elongate strip of a mixture of 80% carbon with 20% polytetrafluoroethylene which is 78 feet long, 5 inches wide and of the order of 0.08 inches in thickness. The inert spacing member between the electrodes is an elongate strip of polypropylene lattice-work screening, which similarly is approximately 78 feet long, 5 inches wide and about 0.08 inches in thickness (individual strand diameter, approx. 0.04 inches). The resulting sandwich or laminate of copper and carbon electrodes with an intermediate polypropylene spacer (78 feet long, 5 inches wide and 1/4 inch thick) is arranged in a spiral extending outwardly from the central core 18 to the outer cylindrical shell 12. As illustrated in FIGS. 5 and 6, the active copper electrode 80 is connected to the outer terminal 74 by means of an outer electrode clip 75. The carbon electrode 82 is similarly connected to the inert terminal 72 by means of an inner electrode clip (not shown) positioned adjacent the central core 18.
Upon discharge of a fully charged cell of the type described (represented by plating lithium on the copper electrode to a thickness of 0.04 inches) the practical discharge capacity of the cell closely approaches the theoretical capacity, that is, 4800 ampere hours for each 785 grams of lithium dithionite. The described battery cell thus has a discharge capacity approximating 16 times the practical limit of the conventional lead-acid cell of corresponding space dimensions and weight. This is computed as follows: lithium will be plated on the negative electrode to a thickness of 0.0025 inches for each 785 grams of lithium dithionite delivered, representing 300 ampere hours. Since the available space for plating of lithium in the described battery cell is 0.04 inches, the available watt hours per pound will be:
(0.0400/0.0025) × 300 ampere hours = 4800 ampere hours
In general terms, 300 ampere hours of energy storage is equivalent to 16 watt hours per pound of available plated lithium. A total of 4800 ampere hours is therefore 16 times the limit of the conventional lead-acid cell of similar weight and dimensions.
In a particular application of the described battery cell, designed to provide a 240 volt/300 ampere hour system, 78 individual battery cells are operated in series to provide the essential propulsive power. Each cell, including battery chamber 10 and circulatory chamber 40 has a total volume of 1600 ml (cell volume 100 ml and reservoir volume 1500 ml). The electrolyte comprises 1600 ml of acetonitrile, saturated with SO 2 , and circulating over 15 grams of Li 2 S 2 O 4 and 75 grams of LiClO 4 initially placed in the circulatory chamber 40. In a test sequence, involving several 10 second charge and discharge cycles to assure continuity and a 10 minute chage at 0.5 amps, discharge characteristics with respect to a 150 ohm load and a current flow of 0.02± amps, are represented in Table I below:
Table I______________________________________Discharge DischargeTime Voltage______________________________________0 2.9471 min. 2.9392 min. 2.9295 min. 2.90410 min. 2.848______________________________________
In general, operational characteristics were excellent, with a cell life of 1.5 hours before recharging, and a peak amperage of 300 amps.
It has been determined that the improved battery cell and system of the present invention provides many advantages. Specifically, because there is no build up or scaling within the cell, the battery cell is found to be rechargeable many times. Recharging of the cell is easily accomplished because of the presence of dissolved SO 2 gas within the electrolyte solution, permitting easier reversibility to the active metal dithionite. Moreover, the circulation of the electrolyte over a gross supply of solid dithionite permits a large capacity battery with battery cell size limitations which are, conversely, quite small. The battery cell is particularly advantageous in that it can be operated at constant ambient temperatures and at atmosperic pressures.
Improved battery cells employing the active metal dithionite provide a further advantage in enabling use of low atomic weight active metals such as lithium, sodium, potassium, magnesium and calcium, without concern as to problems of exposure to air or necessity of using controlled atmospheres or mineral oils in admixture with the active metal. Moreover, the charging sequence is entirely new in that the active metal is plated directly on an electrode during charging of the battery so as to be available for discharge. The battery cell thus has application for primary as well as secondary cells. Thus, following plating of the lithium on the electrode, the lithium dithionite electrolyte can be evacuated from the cell and be replaced with an electrolyte of different discharge characteristics, for example, sulfuryl chloride or thionyl chloride.
A principal advantage of the improved dithionite battery cells resides in the provision of maximum energy and current density ratios as well as power/weight ratios (generally 10 to 20 times those previously available with conventional battery cells), thus making possible for the first time the potential for battery operation and propulsion of primary vehicles and marine craft such as automobiles, trucks, power boats and submarines. Other advantages inherent in the use of the improved battery cells and systems herein disclosed will be apparent to those skilled in the art to which the invention pertains, which is not intended to be limited to the specific disclosures herein except as limited by the appended claims. | An ambient temperature electric cell of primary and secondary nature, characterized by the use of the dithionite salt of an active (alkali or an alkaline earth) metal as the charging agent, and including processes for manufacturing and for operating the same. The dithionite salt is dissolved and suspended in an anhydrous electrolyte comprised of a suitable solvent, which may also contain another salt of the same active metal and may be saturated with sulfur dioxide. To form the cell, a sealed and evacuated enclosure having a negative electrode and a positive current gathering electrode is filled with the electrolyte and subjected to a charging current sufficient to plate the active metal onto the negative electrode, while the positive electrode is saturated with sulfur dioxide. In the case of a secondary cell, the dithionite produced upon discharge is available as a partially dissolved and suspended salt in the electrolyte. Such availability may be enhanced by a system for forced circulation of the electrolyte. In the case of a primary cell, the final cell potential and discharge characteristics may be enhanced by replacing the dithionite electrolyte with other anhydrous electrolyte solutions (e.g., sulfuryl chloride or thionyl chloride) once the lithium has been plated out. The cell is characterized by extremely low internal resistance, long shelf life and excellent performance over a wide temperature range. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention discloses a method and composition for the topical treatment of streptococcal infections by the use of a lysin enzyme blended with a carrier suitable for topical application to dermal tissues.
2. Description of the Prior Art
The genus Streptococcus is comprised of a wide variety of both pathogenic and commensal gram-positive bacteria which are found to inhabit a wide range of hosts, including humans, horses, pigs, and cows. Within the host, streptococci are often found to colonize the mucosa surfaces of the mouth, nares and pharynx. However, in certain circumstances, they may also inhabit the skin, heart or muscle tissue.
Pathogenic streptococci of man include S. pyogenes, S. pneumoniae, and S. faecalis. While Group A streptococci can be present in the throat or on the skin and cause no symptoms of disease, they may also cause infections that range from mild to sever and even life-threatening. Among the pathogenic hemolytic streptococci, S. pyogenes, or group A streptococci have been implicated as the etiologic agent of acute pharyngitis "(strep throat"), impetigo, rheumatic fever, scarlet fever, glomerulonephritis, and invasive fasciitis. Necrotizing fasciitis (sometimes described by the media as "the flesh-eating bacteria") is a destructive infection of muscle and fat tissue. Invasive group A streptococcal infections occur when the bacteria get past the defenses of the person who is infected. About 10,000 to 15,000 cases of invasive GAS disease occur in the United States each year resulting in over 2,000 deaths. CDC estimates that 500 to 1,500 cases of necrotizing fasciitis and 2,000 to 3,000 cases of streptococcal toxic shock syndrome occur each year in the United States. Approximately 20% of patients with necrotizing fasciitis die, and 60% of patients with streptococcal toxic shock syndrome die. About 10 to 15% of patients with other forms of invasive group A streptococcal disease die.
Additionally, Group C Streptococcus can cause cellulitis from skin breaks, although cellulitis is normally associated with Staphylococcus aureus. Cellulitis can result in death, particularly in older individuals or in individuals who are already weakened.
The first individual to identify the serological and immunological groups of streptococci was Dr. Rebecca Lancefield, (Lancefield, R. C., "A Serological Differentiation of Human and other Groups of Hemolytic Streptococci," J. Exp. Med., Vol.57, pp 571-595 1933), after whom the grouping system was named. The group A streptococcus was identified on the basis of B-1, 4 N-acetylglucosamine terminal sugar moieties on a repeating rhamnose sugar backbone found as part of the structure of the organism's cell wall. Antiserum raised against group A streptococci and subsequent absorptions to remove cross-reactions were shown to specifically react with the cell wall component of these organisms and became the grouping antisera for group A streptococci. A number of methods have been devised to fragment the group A streptococcal cell wall carbohydrate. These methods include heating by boiling at pH 2.0, autoclaving, trichloroacetic acid extraction, hot formamide digestion, nitrous acid extraction and enzyme digestion by enzymes derived from the soil microorganisms of species streptomyces, and the phage-associated enzyme lysin. Each of these methods have various advantages and disadvantages.
The rapid diagnosis of group A streptococcal pharyngitis has become more readily available to both physicians and clinical laboratories by replacing time consuming culturing methods requiring a minimum of 24 to 72 hours to identify the presence of group A streptococci with a rapid antigen-antibody test capable of being performed and read in less than one hour. Culturing methods vary in the degree of sensitivity of detection. In one case, a simple 5% sheep blood agar plate may be used in conjunction with a Bacitracin disc and culturing 24 hours at 37 degree(s) C. aerobically to identify group A streptococci. Alternatively, selective media and anaerobic conditions may be used to inhibit overgrowth by other organisms and incubation at 35 degree(s) C. for a minimum of 48 hours. In addition, depending on the transport media, the delay in testing, and any antibacterial agents that the patient may have taken, culturing may result in nonviable organisms that fail to grow in the media although the patient is indeed colonized by the group A streptococcus. In the latter case a sensitive immunoassay for group A streptococcal antigen can detect these nonviable organisms.
In the past, antibiotics were used to treat Streptococcal infections. U.S. Pat. No. 5,260,292 (Robinson et al.) discloses the topical treatment of acne with aminopenicillins. The mouth and composition for topically treating acne and acneiform dermal disorders includes applying an amount of an antibiotic selected from the group consisting of ampicillin, amoxicillin, other aminopenicillins, and cephalosporins, and derivatives and analogs thereof, effective to treat the acne and acneiform dermal disorders.
U.S. Pat. No. 5,409,917 (Robinson et al.) discloses the topical treatment of acne with cephalosporins.
Neither of these applications specifically call for the treatment of streptococcal infections, nor do they address the problems of streptococcal cellulitis or necrotizing fasciitis. Additionally, the use of these antibiotics are presenting new problems. Specifically, a growing number of people are allergic to penicillin, one of the primary antibiotics used to treat Streptococcal infections. Even when penicillin can be used, penicillin resistant strains of Staphylococcal aureus which may be present in the organism can produce penicillinase, which can destroy the penicillin before it has time to act on the Streptococcus. Erythramycin can be used to treat Streptococcal infections; however, 20-30% of Streptococcus are resistant to erythramycin. Also, it is hypothesized that some streptococcus can lie dormant for up to ten days; cells which are not reproducing will not be killed by traditional antibiotics.
Consequently, other efforts have been sought to first identify and then kill Streptococcus.
Maxted, (Maxted, W. R., "The Active Agent in Nascent Phage Lysis of Streptococci," J. Gen Micro, vol 16, pp 585-595 1957), Krause, (Krause, R. M., "Studies on the Bacteriophages of Hemolytic Streptococci," J. Exp Med, vol 108, pp 803-821, 1958), and Fischetti, (Fischetti, V. A., et al, "Purification and Physical Properties of Group C Streptococcal Phage Associated Lysin," J. Exp Med, Vol 133 pp 1105-1117 1971), have reported the characteristics of an enzyme produced by the group C streptococcal organism after being infected with a particular bacteriophage identified as C1. The enzyme was given the name lysin and was found to specifically cleave the cell wall of group A, group C and group E streptococci. These investigators provided information on the characteristics and activities of this enzyme with regard to lysing the group A streptococci and releasing the cell wall carbohydrate. They never reported on the utility of this enzyme in an immunological diagnostic test for the detection of group A streptococci from throat swabs in patients. The failure to use this enzyme for a clinical diagnostic test was due to a number of problems associated with the enzyme such as: the difficulty in growing large amounts of bacteriophage in the group C streptococci, the time delays in inactivating the residual enzyme when trying to obtain phage stocks, the instability of the enzyme itself to oxidative conditions and heat, and nonspecific reactions in immunoassays performed in the presence of other organisms and the biological components in the sample.
U.S. Pat. No. 5,604,109 (Fischetti et al.) teaches the rapid and sensitive detection of group A streptococcal antigens by a diagnostic test kit which utilizes a sampling device consisting of a throat swab made of synthetic or natural fibers such as Dacron or rayon and some type of shaft which holds the fibers, is long enough to place the fibers in the tonsillar area and is capable of being used to swab the area to remove sufficient numbers of colonizing or infecting organisms. The swab can then be placed in the enzyme extraction reagent and subsequently used in an immunoassay. The invention can comprise a test kit for detecting Group A streptococci, containing the lysin enzyme for releasing Group A streptococcal components, and a ligand capable of binding with a component of the Group A streptococcus.
U.S. patent (application Ser. No. 08/962,523) (Fischetti, et. al.) and U.S. patent (application Ser. No. 09/257,026) (Fischetti et al.) disclose the use of an oral delivery mode, such as a candy, chewing gum, lozenge, troche, tablet, a powder, an aerosol, a liquid or a liquid spray, containing a lysin enzyme produced by group C streptococcal bacteria infected with a C1 bacteriophage for the prophylactic and therapeutic treatment of Streptococcal A throat infections, commonly known as strep throat.
None of the prior art suggests the use of the lysin enzyme for the treatment of topical or dermatological infections.
SUMMARY OF THE INVENTION
The present invention (which incorporates U.S. Pat. No. 5,604,109, and U.S. patent application Ser. No. 09/257,026 (Fischetti et al.) and U.S. patent application Ser. No. 08/962,523 (Fischetti) in their entirety by reference) is a composition containing uses a therapeutic agent which comprises the lysin enzyme produced by the group C streptococcal organism after being infected with a particular bacteriophage (identified as C1) for application to the streptococcal infected dermatological part of the body as a method to fight a streptococcal infection, particularly those infections, such as impetigo, which result in invasive fascfitis, necrotizing fasciitis, and the streptococcal form of cellulitis. Based upon the discovery that phage lysin can effectively and efficiently break down the cell walls of Group A Streptococci, with the resultant antigenic fragments being reactive with antibodies specific for the Group A Streptococcal carbohydrate, the composition is particularly useful as a therapeutic treatment of Streptococcal dermatological infections. The semipurified enzyme lacks proteolytic enzymatic activity and therefore is non-destructive to specific antibodies when present during the digestion of the bacterial cell wall. Treatment of group A streptococci with dilute samples of lysin results in the removal of the organism's protective cell wall by the enzyme, thereby killing the strep organism. The treatment of streptococci in biological fluids in vivo has the same effect.
In one embodiment of the invention, the lysin enzyme would be administered in the form of a topical ointment or cream. In another embodiment of the invention, the lysin enzyme would be administered in an aqueous form.
In yet another embodiment of the invention, lysostaphin, the enzyme which lyses Staphylococcus aureus, can be included in the therapeutic agent. In a further embodiment of the invention, conventional antibiotics may be included in the therapeutic agent with the lysin enzyme, and with or without the presence of lysostaphin. Other bacterial lysing enzymes may also be included in the therapeutic agent.
DETAILED DESCRIPTION OF THE INVENTION
Treatment of group A streptococci with dilute samples of lysin results in the removal of the organism's protective cell wall by the enzyme, thereby killing the strep organism. The presence of the lysin on a dermatological tissue when streptococci are present results in the killing of the streptococci, thus cutting short the invasive process and further skin and tissue damage. This rapid and specific (lethal) activity of the lysin enzyme against streptococcus will have a profound beneficial effect by killing even "dormant" cells, which are not killed by conventional antibiotics, which rely upon the cells reproducing in order to kill the bacteria.
The amidase muralytic (lysin) enzyme produced by the group C streptococcal organism after being infected with a particular bacteriophage (identified as Cl) is isolated and harvested as is described in U.S. patent application Ser. No. 5,604,109. This Group C streptococcal enzyme, (also known as a lysin enzyme) which has unique specificity for the cell wall of groups A, C, and E Streptococci, may alternatively be isolated and harvested by any other known means.
The composition which may be used for the therapeutic treatment of a strep dermatological infection includes the lysin enzyme and, preferably, a mode of application (such as a carrier), to the skin or tissue, such that the enzyme is put in the carrier system which holds the enzyme on the skin.
Prior to, or at the time the enzyme is put in the carrier system, it is preferred that the enzyme be in a stabilizing buffer environment for maintaining a pH range between about 4.0 and about 8.0, more preferably between about 5.5 and about 7.5 and most preferably at about 6.1.
The stabilizing buffer should allow for the optimum activity of the lysin enzyme. The buffer may be a reducing reagent, such as dithiothreitol. The stabilizing buffer may also be or include a metal chelating reagent, such as ethylenediaminetetracetic acid disodium salt, or it may also contain a phosphate or citrate-phosphate buffer.
To prevent spoilage, the stabilizing buffer may further contain a bactericidal or bacteriostatic reagent as a preservative, such as a small amount of sodium benzoate.
The mode of application for the lysin enzyme includes a number of different types and combinations of carriers which include, but are not limited to an aqueous liquid, an alcohol base liquid,, a water soluble gel, a lotion, an ointment, a nonaqueous liquid base, a mineral oil base, a blend of mineral oil and petrolatum, lanolin, liposomes, protein carriers such as serum albumin or gelatin, powdered cellulose carmel, and combinations thereof. A mode of delivery of the carrier containing the therapeutic agent includes but is not limited to a smear, spray, a time-release patch, a liquid absorbed wipe, and combinations thereof.
More specifically, the carriers of the compositions of the present invention may comprise semi-solid and gel-like vehicles that include a polymer thickener, water, preservatives, active surfactants or emulsifiers, antioxidants, sun screens, and a solvent or mixed solvent system. U.S. Pat. No. 5,863,560 (Osbome) discusses a number of different carrier combinations which can aid in the exposure of the skin to a medicament.
Polymer thickeners that may be used include those known to one skilled in the art, such as hydrophilic and hydroalcoholic gelling agents frequently used in the cosmetic and pharmaceutical industries. Preferably, the hydrophilic or hydroalcoholic gelling agent comprises "CARBOPOL®" (B.F. Goodrich, Cleveland, Ohio), "HYPAN®1" (Kingston Technologies, Dayton, N.J.), "NATROSOL®" (Aqualon, Wilmington, Del.), "KLUCEL®" (Aqualon, Wilmington, Del.), or "STABILEZE®" (ISP Technologies, Wayne, N.J.). Preferably, the gelling agent comprises between about 0.2% to about 4% by weight of the composition. More particularly, the preferred compositional weight percent range for "CARBOPOL®" is between about 0.5% to about 2%, while the preferred weight percent range for "NATROSOL®" and "KLUCEL®" is between about 0.5% to about 4%. The preferred compositional weight percent range for both "HYPAN®" and "STABILEZE®" is between about 0.5% to about 4%.
"CARBOPOL®" is one of numerous cross-linked acrylic acid polymers that are given the general adopted name carbomer. These polymers dissolve in water and form a clear or slightly hazy gel upon neutralization with a caustic material such as sodium hydroxide, potassium hydroxide, triethanolamine, or other amine bases. "KLUCEL®" is a cellulose polymer that is dispersed in water and forms a uniform gel upon complete hydration. Other preferred gelling polymers include hydroxyethylcellulose, cellulose gum, MVE/MA decadiene crosspolymer, PVM/MA copolymer, or a combination thereof.
Preservatives may also be used in this invention and preferably comprise about 0.05% to 0.5% by weight of the total composition. The use of preservatives assures that if the product is microbially contaminated, the formulation will prevent or diminish microorganism growth. Some preservatives useful in this invention include methylparaben, propylparaben, butylparaben, chloroxylenol, sodium benzoate, DMDM Hydantoin, 3-Iodo-2-Propylbutyl carbamate, potassium sorbate, chlorhexidine digluconate, or a combination thereof.
Titanium dioxide may be used as a sunscreen to serve as prophylaxis against photosensitization. Alternative sun screens include methyl cinnamate. Moreover, BHA may be used as an antioxidant, as well as to protect ethoxydiglycol and/or dapsone from discoloration due to oxidation. An alternate antioxidant is BHT.
Pharmaceuticals for use in all embodiments of the invention include antimicrobial agents, anti-inflammatory agents, antiviral agents, local anesthetic agents, corticosteroids, destructive therapy agents, antifungals, and antiandrogens. In the treatment of acne, active pharmaceuticals that may be used include antimicrobial agents, especially those having anti-inflammatory properties such as dapsone, erythromycin, minocycline, tetracycline, clindamycin, and other antimicrobials. The preferred weight percentages for the antimicrobials are 0.5% to 10%.
Local anesthetics include tetracaine, tetracaine hydrochloride, lidocaine, lidocaine hydrochloride, dyclonine, dyclonine hydrochloride, dimethisoquin hydrochloride, dibucaine, dibucaine hydrochloride, butambenpicrate, and pramoxine hydrochloride. A preferred concentration for local anesthetics is about 0.025% to 5% by weight of the total composition. Anesthetics such as benzocaine may also be used at a preferred concentration of about 2% to 25% by weight.
Corticosteroids that may be used include betamethasone dipropionate, fluocinolone acetonide, betamethasone valerate, triamcinolone acetonide, clobetasol propionate, desoximetasone, diflorasone diacetate, amcinonide, flurandrenolide, hydrocortisone valerate, hydrocortisone butyrate, and desonide are recommended at concentrations of about 0.01% to 1.0% by weight. Preferred concentrations for corticosteroids such as hydrocortisone or methylprednisolone acetate are from about 0.2% to about 5.0% by weight.
Destructive therapy agents such as salicylic acid or lactic acid may also be used. A concentration of about 2% to about 40% by weight is preferred. Cantharidin is preferably utilized in a concentration of about 5% to about 30% by weight. Typical antifungals that may be used in this invention and their preferred weight concentrations include: oxiconazole nitrate (0.1% to 5.0%), ciclopirox olamine (0.1% to 5.0%), ketoconazole (0.1% to 5.0%), miconazole nitrate (0.1% to 5.0%), and butoconazole nitrate (0.1% to 5.0%). For the topical treatment of seborrheic dermatitis, hirsutism, acne, and alopecia, the active pharmaceutical may include an antiandrogen such as flutamide or finasteride in preferred weight percentages of about 0.5% to 10%.
Typically, treatments using a combination of drugs include antibiotics in combination with local anesthetics such as polymycin B sulfate and neomycin sulfate in combination with tetracaine for topical antibiotic gels to provide prophylaxis against infection and relief of pain. Another example is the use of minoxidil in combination with a corticosteroid such as betamethasone diproprionate for the treatment of alopecia ereata. The combination of an anti-inflammatory such as cortisone with an antifungal such as ketoconazole for the treatment of tinea infections is also an example.
In one embodiment, the invention comprises a dermatological composition having about 0.5% to 10% carbomer and about 0.5% to 10% of a pharmaceutical that exists in both a dissolved state and a microparticulate state. The dissolved pharmaceutical has the capacity to cross the stratum corneum, whereas the microparticulate pharmaceutical does not. Addition of an amine base, potassium, hydroxide solution, or sodium hydroxide solution completes the formation of the gel. More particularly, the pharmaceutical may include dapsone, an antimicrobial agent having anti-inflammatory properties. A preferred ratio of micro particulate to dissolved dapsone is five or less.
In another embodiment, the invention comprises about 1% carbomer, about 80-90% water, about 10% ethoxydiglycol, about 0.2% methylparaben, about 0.3% to 3.0% dapsone including both micro particulate dapsone and dissolved dapsone, and about 2% caustic material. More particularly, the carbomer may include "CARBOPOL® 980" and the caustic material may include sodium hydroxide solution.
In a preferred embodiment, the composition comprises dapsone and ethoxydiglycol, which allows for an optimized ratio of micro particulate drug to dissolved drug. This ratio determines the amount of drug delivered, compared to the amount of drug retained in or above the stratum corneum to function in the supracorneum domain. The system of dapsone and ethoxydiglycol may include purified water combined with "CARBOPOL®" gelling polymer, methylparaben, propylparaben, titanium dioxide, BHA, and a caustic material to neutralize the "CARBOPOL®."
Any of the carriers for the lysin enzyme may be manufactured by conventional means. However, if alcohol is used in the carrier, the enzyme should be in a micelie, liposome, or a "reverse" liposome, to prevent denaturing of the enzyme. Similarly, when the lysin enzyme is being placed in the carrier, and the carrier is, or has been heated, such placement should be made after the carrier has cooled somewhat, to avoid heat denaturation of the enzyme. In a preferred embodiment of the invention, the carrier is sterile.
The enzyme may be added to these substances in a liquid form or in a lyophilized state, whereupon it will be solubilized when it meets a liquid body.
The effective dosage rates or amounts of the lysin enzyme to treat the infection, and the duration of treatment will depend in part on the seriousness of the infection, the duration of exposure of the recipient to the Streptococci, the number of square centimeters of skin or tissue which are infected, the depth of the infection, the seriousness of the infection, and a variety of a number of other variables. The composition may be applied anywhere from once to several times a day, and may be applied for a short or long term period. The usage may last for days or weeks. Any dosage form employed should provide for a minimum number of units for a minimum amount of time. The concentration of the active units of enzyme believed to provide for an effective amount or dosage of enzyme may be in the range of about 100 units/ml to about 500,000 units/mil of composition, preferably in the range of about 1000 units/ml to about 100,000 units/ml, and most preferably from about 10,000 to 100,000 units/ml. The amount of active units per ml and the duration of time of exposure depends on the nature of infection, and the amount of contact the carrier allows the lysin enzyme to have. It is to be remembered that the enzyme works best when in a fluid environment. Hence, effectiveness of the enzyme is in part related to the amount of moisture trapped by the carrier. In another preferred embodiment, a mild surfactant in an amount effective to potentiate the therapeutic effect of the lysin enzyme. Suitable mild surfactants include, inter alia, esters of polyoxyethylene sorbitan and fatty acids (Tween series), octylphenoxy polyethoxy ethanol (Triton-X series), n-Octyl-β-D-glucopyranoside, n-Octyl-β-D-thioglucopyranoside, n-Decyl-β-D-glucopyranoside, n-Dodecyl-β-D-glucopyranoside, and biologically occurring surfactants, e.g., fatty acids, glycerides, monoglycerides, deoxycholate and esters of deoxycholate.
In order to accelerate treatment of the infection, and to treat any non-Streptococcus bacteria, the therapeutic agent may further include at least one complementary agent which can also potentiate the bactericidal activity of the lysin enzyme. The complementary agent can be penicillin, synthetic penicillins bacitracin, methicillin, cephalosporin, polymyxin, cefaclor. Cefadroxil, cefamandole nafate, cefazolin, cefixime, cefinetazole, cefonioid, cefoperazone, ceforanide, cefotanme, cefotaxime, cefotetan, cefoxitin, cefpodoxime proxetil, ceftazidime, ceftizoxime, ceftriaxone, cefriaxone moxalactam, cefiroxime, cephalexin, cephalosporin C, cephalosporin C sodium salt, cephalothin, cephalothin sodium salt, cephapirin, cephradine, cefuroximeaxetil, dihydratecephalothin, moxalactam, loracarbef, mafate, chelating agents and any combinations thereof in amounts which are effective to synergistically enhance the therapeutic effect of the lysin enzyme.
Additionally, the therapeutic agent may further comprise the enzyme lysostaphin for the treatment of any Staphylococcus aureus bacteria. Mucolytic peptides, such as lysostaphin, have been suggested to be efficacious in the treatment of S. aureus infections of humans (Schaffter et al., Yale J. Biol. & Med., 39:230 (1967) and bovine mastitis caused by S. aureus (Sears et al., J. Dairy Science, 71 (Suppl. 1): 244(1988)). Lysostaphin, a gene product of Staphylococcus simulans, exerts a bacteriostatic and bactericidal effect upon S. aureus by enzymatically degrading the polyglycine crosslinks of the cell wall (Browder et al., Res. Comm., 19: 393-400 (1965)). U.S. Pat. No. 3,278,378 describes fermentation methods for producing lysostaphin from culture media of S. staphylolyticus, later renamed S. simulans. Other methods for producing lysostaphin are further described in U.S. Pat. Nos. 3,398,056 and 3,594,284. The gene forlysostaphin has subsequently been cloned and sequenced (Recsei et al., Proc. Natl. Acad. Sci. USA, 84: 1127-1131 (1987)). The recombinant mucolytic bactericidal protein, such as r-lysostaphin, can potentially circumvent problems associated with current antibiotic therapy because of its targeted specificity, low toxicity and possible reduction of biologically active residues. Furthermore, lysostaphin is also active against non-dividing cells, while most antibiotics require actively dividing cells to mediate their effects (Dixon et al., Yale J. Biology and Medicine, 41: 62-68 (1968)). Lysostaphin, in combination with the lysin enzyme, can be used in the presence or absence of the listed antibiotics. There is a degree of added importance in using both lysostaphin and the lysin enzyme in the same therapeutic agent. Frequently, when a body has a bacterial infection, the infection by one genus of bacteria weakens the body or changes the bacterial flora of the body, allowing other potentially pathogenic bacteria to infect the body. One of the bacteria that sometimes co-infects a body is Staphylococcus aureus. Many strains of Staphylococcus aureus produce penicillinase, such that both the Staphylococcus and the Streptococcus strains will not be killed by standard antibiotics. Consequently, the use of the lysin and lysostaphin, possibly in combination with antibiotics, can serve as the most rapid and effective treatment of bacterial infections. In yet another preferred embodiment, the invention may include mutanolysin, and lysozyme.
While this treatment may be used in any mammalian species, the preferred use of this product is for a human.
Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood within the scope of the appended claims the invention may be protected otherwise than as specifically described. | The present invention discloses a method and composition for the topical treatment of streptococcal infections by the use of a lysin enzyme blended with a carrier suitable for topical application to dermal tissues. The method for the treatment of dermatological streptococcal infections comprises administering a composition comprising effective amount of a therapeutic agent, with the therapeutic agent comprising a lysin enzyme produced by group C streptococcal bacteria infected with a C1 bacteriophage. The therapeutic agent can be in a pharmaceutically acceptable carrier. |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/940,762, filed on 30 May 2007.
FIELD OF THE PRESENT INVENTION
[0002] The present invention is directed to a cable tie having an elongate strap and a locking head and, more particularly, to a metallic cable tie for holding a plurality of articles together in a bundle, while reducing the band thread force present in the elongate strap and allowing for the elongate strap to be fed through the locking head a plurality of times.
BACKGROUND OF THE PRESENT INVENTION
[0003] Metallic bundling devices, such as cable ties, that incorporate locking balls and roller pins have been used for bundling a great variety of items, such as, for example, bales of cotton or a multitude of wires. A common name for these types of cable ties is the “ball lock” or “roller lock” device. In such devices, an elongate metallic strap is wrapped around the objects to be bundled and inserted into a locking head. Contained within the locking head is a metallic ball which, using the shape of the locking head (generally angled towards one end) as well as the force of gravity, lock the elongate metallic strap in place. Gravity also allows the detachment of the elongate metallic strap. By turning the locking head upside down, gravity permits the metallic ball to roll towards the other end of the locking head, thus freeing and allowing the elongate metallic strap to be removed from the locking head. Generally speaking, this process provides a bundling apparatus having a relatively high holding strength.
[0004] Various means have since been introduced in an effort to further strengthen these types of bundling apparati. One example has been the “double ball” assembly. In this assembly, the properties of two metallic balls combine to provide an even higher holding strength than that available with only one metallic ball. An example of this “double ball” assembly is disclosed in a U.S. Provisional Patent Application No. 60/886,552, entitled “Retained Tension Multiple Ball Lock Cable Tie,” assigned to the same entity as the Assignee of the present invention, and filed on 25 Jan. 2007. The disclosure of this U.S. Provisional Patent Application, as well as its Non-Provisional Counterpart (U.S. patent application Ser. No. 12/018,978, filed on 24 Jan. 2008), are incorporated by reference herein in their entireties.
[0005] Another example of a means to further strengthen “ball lock” cable ties is the “double loop” assembly. In this assembly, the elongate metallic strap is threaded through the locking head more than one time. The result is a bundling apparatus having a very high holding strength.
[0006] Both the “double ball” and the “double loop” assemblies provide a heightened level of holding strength. Additionally, both assemblies are adaptable for many uses.
[0007] However, the “double loop” assembly is not without its drawbacks. FIG. 1 represents the current state of the art in “double loop” cable tie assemblies. Referring to FIG. 1 , the initial insertion of the elongate metallic strap into the locking head causes a phenomenon known as “band thread force.” The band thread force results from the fact that the floor of the locking head is flat, while the elongate metallic strap, when wrapped around the bundle of articles, takes on an arcuate form. Thus, the elongate metallic strap does not sit flush against the floor of the locking head. In “single loop” assemblies, this is not a major issue, as the roller means can nevertheless lock into place within the locking head and prohibit the release of the elongate metallic strap from the locking head. However, in “double loop” assemblies, the band thread force makes it difficult to thread the elongate metallic strap in the locking head a second time.
[0008] U.S. Pat. No. 6,076,235, entitled “Cable Tie” and issued to Wasim Khokhar on 20 Jun. 2000, illustrates one attempt to develop a locking head that provides a reduction in the band thread force. In the locking head disclosed in the '235 patent, a notch was formed in the floor of the locking head proximate the strap entry face. This provided for a slight release of the band thread force within the locking head. U.S. Pat. No. 4,765,032, entitled “Environmental Bundling Tie,” and issued to William A. Fortsch on 23 Aug. 1998, also attempted to solve the band thread force problem by employing a similar solution. Both disclosures of the '235 and the '032 patents are hereby incorporated by reference in their entireties.
[0009] Although the above references attempted to provide a solution to the problem of the band thread force, a substantial reduction in the band thread force did not result, and the issue still remains. Thus, it would be desirable to provide a “double loop” cable tie assembly having a substantially-reduced band thread force that overcomes the disadvantages in the previously disclosed devices.
SUMMARY OF THE PRESENT INVENTION
[0010] A cable tie with a reduced band thread force is disclosed, comprising an elongate metallic strap, a metallic locking head and a metallic roller means. In one embodiment, the metallic locking head comprises a strap entry notch. In another embodiment, the metallic locking head comprises a strap entry notch and a strap exit notch. In operation, the configuration of the notches, singularly or in tandem, serve to reduce the band thread force in the elongate metallic strap when the elongate metallic strap is inserted into the metallic locking head a second (and subsequent) time.
BRIEF DESCRIPTION OF THE FIGURES
[0011] FIG. 1 illustrates a side view of the current state of a metal cable tie adaptable for a “double loop” assembly;
[0012] FIG. 2 illustrates a perspective view of a metal cable tie, manufactured in accordance with the tenets and teachings of the present invention shown secured around a bundle of wires;
[0013] FIG. 3 illustrates a perspective view of the locking head of the metal cable tie of FIG. 2 ;
[0014] FIG. 4 illustrates a side sectional view of the elongate strap and the locking head of the metal cable tie of FIG. 2 ;
[0015] FIG. 5 illustrates an underside perspective view of the locking head of the metal cable tie of FIG. 2 ;
[0016] FIG. 6 illustrates a front sectional view of the elongate strap and the locking head of the metal cable tie of FIG. 2 ;
[0017] FIG. 7 illustrates a top perspective view of the metal cable tie of FIG. 2 ;
[0018] FIG. 8 illustrates a perspective view of an alternate embodiment of the locking head of the metal cable tie of FIG. 2 ; and
[0019] FIG. 9 illustrates a side sectional view of an alternate embodiment of the elongate strap and the locking head of the metal cable tie of FIG. 2 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The illustrated embodiments of the present invention are directed to a three-piece cable tie that uses a combination of a roller means and a locking head to secure an elongate strap therein.
[0021] Referring now to the Figures, in which like elements are represented by the same reference numerals, a cable tie for bundling a plurality of elongate objects, such as wires 12 , and for holding those elongated objects together, is generally indicated in FIG. 2 by reference numeral 10 . Cable tie 10 preferably includes locking head 14 and roller means (not visible in FIG. 2 ). As more clearly illustrated in FIGS. 3-9 , locking head 14 preferably receives first end 16 of elongate strap 18 , and is adapted to additionally receive second end 20 of elongate strap 18 . Additionally, second end 20 of elongate strap 18 may be inserted into locking head 14 a subsequent time. As is illustrated by the Figures, elongate strap 18 is fed through locking head 14 in such a manner that there is no secure connection between locking head 14 and elongate strap 18 . Nevertheless, the tenets and teachings of the present invention will be achieved, as the insertion of elongate strap 18 into locking head 14 a second (and any subsequent) time will prevent the unraveling of elongate strap 18 , based on the effects of friction between the portions of elongate strap 18 in contact with each other, as well as the effects of both gravity and geometry on roller means 22 . Alternatively, as is illustrated by FIG. 4 , first end 16 of elongate strap 18 may be secured to locking head 14 by any known means. Roller means 22 is preferably illustrated in the form of a ball or sphere-like object, most clearly illustrated in FIG. 4 , for retaining elongate strap 18 within locking head 14 .
[0022] Roller means 22 , locking head 14 and elongate strap 18 each can be formed of stainless steel—or any other suitable material, including both other metals and plastics—to allow the devices to be used over a wide temperature range and to give cable tie 10 both a high strength and an excellent resistance to corrosion. Additionally, by means currently known in the art, elongate strap 18 may be selectively coated with any known corrosion-resistant coating, such as that disclosed in U.S. Pat. No. 5,103,534 or U.S. patent application Ser. No. 10/794,613, the disclosures of which are hereby incorporated herein by reference in their entireties. Further, elongate strap 18 may also be color coded, according to OSHA safety standards. Moreover, the surface of roller means 22 can be textured or roughened to increase its friction coefficient with the other elements of cable tie 10 (i.e., locking head 14 and elongate strap 18 ).
[0023] FIGS. 3-7 illustrate one embodiment of locking head 14 , in accordance with the tenets and teachings of the present invention, in more detail. Referring to FIGS. 3-7 , locking head 14 is illustrated as generally comprising strap entry face 24 , strap exit face 26 , retention means 28 , first side wall 30 , second side wall 32 , floor 34 and roof 36 .
[0024] Floor 34 and roof 36 are preferably joined by first side wall 30 and second side wall 32 . This is illustrated most clearly in FIG. 6 . In doing so, these elements define strap-receiving aperture 38 , which extends the length of locking head 14 between strap entry face 24 and strap exit face 26 . Referring back to FIGS. 3-6 , it is illustrated that roof 36 diverges in the direction of floor 34 as locking head 14 progresses from strap entry face 24 to strap exit face 26 .
[0025] Additionally with reference to floor 34 , it is illustrated that floor 34 defines strap entry notch 40 . Strap entry notch 40 comprises an indentation within the bottom portion of strap entry face 24 . The size of the indentation, which reduces the overall length of floor 34 , allows a substantial release of the band thread force, thus making it easier to insert elongate strap 18 into strap entry face 24 a subsequent time. As shown in FIG. 4 . the result of the band thread force, shown as open area 42 , is greatly reduced. The reduction in open area 42 provides for a greater strap-receiving aperture 38 , which allows elongate strap 18 to be inserted into locking head 14 a second (and subsequent) time.
[0026] Regarding the locking of cable tie 10 , as more closely illustrated in FIGS. 4 and 7 , roller means 22 is captively held between roof 36 and floor 34 by retention means 28 . Retention means 28 comprises finger 44 extending from roof 36 towards floor 34 adjacent strap exit face 26 .
[0027] It is contemplated that roller means 22 is movable between a threading position, not illustrated in the Figures, wherein roller means 22 is disposed as engaging finger 44 , and proximate to strap exit face 26 , and a locking position, wherein roller means 22 is closer to strap entry face 24 and securely engages elongate strap 18 . In the threading position, roller means 22 concurrently engages finger 44 and roof 36 .
[0028] In operation, and once again referring to the Figures, after elongate strap 18 is wrapped around the objects (e.g., wires 12 ) to be held, second end 20 of elongate strap 18 is inserted into locking head 14 . Continued threading of elongate strap 18 results in positive engagement of elongate strap 18 with roller means 22 at any angle locking head 14 is held. As a result of the strength and nature of elongate strap 18 , a positive band thread force will be exerted upon by elongate strap 18 , thrusting elongate strap 18 up from floor 34 of locking head 14 , through strap-receiving aperture 38 and towards roof 36 of locking head 14 . In some instances, this band thread force may make it extremely difficult to insert second end 20 of elongate strap 18 into locking head 14 a second time. However, due to the placement of strap entry notch 40 , the positive band thread force is reduced, allowing a user to more easily insert second end 20 of elongate strap 18 into locking head 14 a second time.
[0029] In an alternate embodiment, as illustrated in FIGS. 8-9 , strap entry notch 40 may be reduced in length, and locking head 14 is provided with strap exit notch 46 . In this embodiment, strap entry notch 40 and strap exit notch 46 combine to comprise indentations within the bottom portion of strap entry face 24 and strap exit face 26 . Similar to the embodiment described above, the size of the indentations, which reduces the overall length of floor 34 , allows a substantial release of the band thread force, thus making it easier to insert elongate strap 18 into strap entry face 24 a subsequent time. Again, similar to the embodiment described above, as shown in FIG. 9 , the result of the band thread force, shown as open area 44 , is greatly reduced. Thus, the reduction in open area 42 provides for a greater strap-receiving aperture 38 , which allows elongate strap 18 to be inserted into locking head 14 a second (and subsequent) time.
[0030] The disclosed present invention provides a cable tie that allows for a reduction in the band thread force. It should be noted that the above-described and illustrated embodiments and preferred embodiments of the present invention are not an exhaustive listing of the forms such a cable tie in accordance with the present invention might take: rather, they serve as exemplary and illustrative of embodiments of the present invention as presently understood. Many other forms of the present invention exist and are readily apparent to one having ordinary skill in the art. | A cable tie with a reduced band thread force is disclosed, comprising an elongate metallic strap, a metallic locking head and a metallic roller means. In one embodiment, the metallic locking head comprising a strap entry notch. In another embodiment, the metallic locking head comprises a strap entry notch and a strap exit notch. In operation, the configuration of the notches, singularly or in tandem, serve to reduce the band thread force in the elongate metallic strap when the elongate metallic strap is inserted into the metallic locking head a second (and subsequent) time. |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a miniature fluidic connector, and more particularly a miniature fluidic connector that can be accommodated within an electrical connector of the type consisting of a plug and a receptacle, each provided with openings.
2. Description of the Prior Art
The above type of connector is used in particular with printed cards with a built-in heat exchanger of the type comprising a heat drain equipped with a channel system to insure the fluidic connection of the channel network for heat-carrying fluid of the drain of the printed card with the fluidic circuit integrated in the frame of the electronic equipment. A card of this type is described, in particular, in co-filed patent application entitled "Printed Circuit Card With Heat Exchanger and Method for Making Such a Card", the disclosure of which is expressly incorporated herein by reference.
At the present time there are various types of miniature fluidic connectors on the market. But these connectors cannot be mounted in an input/output electrical connector of standard type such as the connectors complying with French standards HE 8, HE 9, and HE 11.
It would be desirable to provide such minature fluidic connectors which can be mounted in such standarized connectors.
SUMMARY OF THE INVENTION
In accordance with this invention, there is provided a miniature fluidic connector mountable in an electrical connector of the type comprising a plug and a receptacle, each provided with openings, characterized in that it comprises a male fluidic contact and a female fluidic contact, the male fluidic contact being constituted by a contact body permitting the passage of heat-carrying fluid, which is designed to be embedded in an opening of the plug or of the receptacle of the electrical connector, the contact body being prolonged on one side by a male tip and the female fluidic contact being constituted by a contact body permitting the passage of the fluid, designed to be embedded in an opening in the other element of the electrical connector, the contact body being prolonged on one side by a female tip shaped to receive the male tip, the male tip and/or female tip projecting in part relative to the end of its respective opening so that, when coupled, the ends of the openings of the plug and the receptacle of the electrical connector will be substantially pressed against one another.
Thus, the fluidic contacts according to the present invention are adapted to the openings or cavities of the existing input/output connectors with no modification. Moreover, the fluidic contacts according to the invention resemble the conventional contacts such as power contacts, coaxial contacts or optical contacts commonly mounted in the said openings, as far as dimensions and outer appearance are concerned.
According to another aspect of the present invention, the miniature fluidic connector is a self-plugging connector. Consequently, the contact body of the male fluidic contact and/or female fluidic contact comprises an inner chamber designed to receive a self-plugging device.
Various types of self-plugging devices can be mounted in the inner chamber of the male contact or the female contact. According to a preferred embodiment, the self-plugging device is constituted by a valve, an elastic device urging the valve into closed position to prevent the passage of fluid, a means for bringing the valve into open position when coupling up, to permit the passage of fluid, and an internal sealing device preventing, in closed position, the passage of fluid outside the contact body toward the tip.
The valve can be made in various ways. Thus, according to a preferred embodiment, the valve is constituted by a skirt sliding in the inner chamber of the contact body and receiving the elastic device, the said skirt being prolonged by a part of smaller diameter equipped with at least one orifice on its perimeter to permit the passage of the fluid between the inner recess of the skirt and the inner chamber of the contact body, the said part terminating in a closure cone. According to another embodiment, the valve is constituted by a solid piece mounted at the end of a guide shaft on which the elastic device is positioned, this guide shaft sliding in a journal mounted in the contact body and equipped with at least one orifice for the passage of heat-carrying fluid.
According to still another embodiment, the valve can be constituted by a ball mounted at the end of the elastic device which in this case is constituted, preferably, by a conical coil spring, the elastic device being held in position in the contact body by shoulders.
According to still another embodiment, the valve can be constituted by a slide valve.
Furthermore, the means for bringing the valve into the open position, on coupling, to permit the passage of the fluid, is preferably constituted by a control rod projecting from the end of the valve into the male and/or female tip.
According to another characteristic of the present invention, the end of the contact body opposite that of the tip is mounted in a coupling which permits the connection to a printed card with a built-in heat exchanger constituted by a drain having a network of channels for the circulation of the heat-carrying fluid.
The fluidic connector described above has numerous advantages. In particular, its size is very small and the fluidic contacts which constitute it are compatible with the standardized openings of the plug or of the receptacle of existing electrical connectors.
Furthermore, the projection of one or both of the fluidic contacts relative to the front end of the plug or of the receptacle of the connector is compatible with the proper operation of the guides and alignment mechanisms of the said connector. Furthermore, each fluidic contact has a small number of parts, and it is thereby very simple in design and hence trouble-free, reliable and sturdy.
Furthermore, in the case of self-plugging miniature fluidic connectors it is possible to operate the insertion and extraction of a card without loss of fluid and without stopping the circulation of the fluid in the frame and in the other cards. Furthermore, the fluidic contact works with minimal losses of pressure in the passage of the fluid despite the very samll dimensions imposed by the openings of the electrical connectors. It withstands the pressure of the heat-carrying fluid both in coupled and uncoupled position. There is no loss of fluid either on the receptacle side of the connector or on the plug side when coupling or uncoupling the card. The number of coupling and uncoupling maneuvers can be high and compatible with the exigencies of conventional connectors. And at the moment of coupling, it will accept an angular disalignment similar to those generally allowed for conventional contacts. It can be made of materials chemically compatible with the nature of the heat-carrying fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a fluidic connector according to the present invention in uncoupled position.
FIG. 2 is a sectional view of the fluidic connector in FIG. 1 in coupled position.
FIG. 3 is a partial view in section of a fluidic contact mounted in the plug of an electrical connector fixed on a card with circulation of fluid representing a variation of the leakproof link between the contact body and the coupling.
FIG. 4 is a perspective view of an embodiment of a clip holding the fluidic contact in the opening of the electrical connector.
FIG. 5 is a partial view in section of another embodiment of the connection of the fluidic contact on the printed card.
FIG. 6 is a partial view in section of still another embodiment of the connection of the fluidic contact with the printed card.
FIG. 7 is a partial view in section of still another embodiment of the connection of the fluidic contact with the printed card.
FIG. 8 is a partial view in section of another embodiment of a fluidic connector according to the present invention, in coupled position.
FIG. 9 is a sectional view of a third embodiment of a fluidic connector according to the present invention.
FIG. 10 is a sectional view of a fourth embodiment of a fluidic connector according to the present invention in coupled position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the figures, for simplicity of the description, the same elements bear the same references.
The various figures represent a fluidic connector according to the present invention mounted in the openings of an input/output electrical connector for a printed card, the printed card being cooled by circulation of a heat-carrying fluid. Nevertheless it will be clear to those skilled in the art that the fluidic connector of the present invention can be mounted in other types of electrical connectors such as rectangular connectors, cylindrical connectors or the like.
FIG. 1 represents a fluidic connector according to the present invention comprising a female fluidic contact 3 mounted in the plug 2 of the electrical connector and joined to the circulation channels of a printed circuit card 1 cooled by circulation of fluid and a male fluidic contact 5 mounted in the receptacle 4 of the said connector. It will be understood by those skilled in the art that the male fluidic contact and the female fluidic contact can be mounted in the reverse manner by adopting the proper connections.
Reference is first made to the female fluidic contact 3 shown in the left-hand side of FIG. 1 and 2. This fluidic contact is constituted by a contact body 68 whose external part insures the embedment of the fluidic contact in the opening 135 of plug 2 of the electrical connector and whose internal part is equipped with a self-plugging device described below, contact body 68 being prolonged by a female tip 69 ensuring the semipermanent connection with the contact of the opposite sex mounted in the receptacle of the connector. The female tip 69 and the contact body 68 appear in the form of two coaxial cylindrical tubes linked to one another, but different in diameter. The outer diameter of the female tip 69 is larger than the outer diameter of contact body 68 so as to form a shoulder 77 for holding in place a clip 143 designed to ensure the attachment of fluidic contact 3 in the opening of plug 2 of the electrical connector. Furthermore, contact body 68 and female tip 69 are separated by an internal partition equipped with an orifice of communication 76.
The inner cavity 72 of female tip 69 of female contact 3 is designed to receive the male tip 101 of contact 5 when the two contacts are coupled. Thus, in order to facilitate this coupling, the inner edge of the entry of cavity 72 has a rounded portion 74 which assists the engagement of male tip 101, by correcting any misalignment of the latter relative to the axis 53 of the female contact and prevents injury to the sealing washer provided on the male tip of the male contact as the latter engages in cavity 72. Furthermore, the outer edge of the entry of cavity 72 has a bevel 73 that assists in the engagement of the outer contour of the female tip in the opening 135' of the receptacle 4 of the connector of the mother card or of the chassis.
In the case of the fluidic connector in FIGS. 1 and 2 the female fluidic contact contains a self-plugging device. It is nevertheless conceivable, without departing from the scope of the present invention, to have a fluidic contact without a self-plugging device.
This self-plugging device is constituted by a valve 90, and an elastic device urging the valve into closed position to prevent the passage of the fluid in uncoupled position, this elastic device being constituted by a coiled compression spring 47 in the embodiment shown, and a means which, during the coupling, brings the valve into open position to permit the passage of the fluid, this means being constituted, for example, by a control rod 91 prolonging the end of the valve and inner sealing device constituted for example by a washer or O-ring 65. This self-plugging device is mounted in the inner chamber 66 of the contact body 68. According to a first embodiment, valve 90 which is made in one piece is constituted by a cylindrical skirt 87 whose external guidance contour 88 slides in inner chamber 66 of contact body 68 and whose inner recess 89 receives compression spring 47. Cylindrical skirt 87 is prolonged by a part 85 smaller in diameter than the skirt and is equipped on its perimeter with orifices 95 to permit the passage of fluid between the inner recess of skirt 87 and the inner chamber of contact body 68. Part 85 terminates in a closure cone 86. In the embodiment shown, the closure cone 86 is prolonged by a control rod 91 of smaller diameter than hole 76 communicating between the contact body and the female tip. Control rod 91 is co-axial to the axis of the contact body and projects into the inner recess 72 of the female tip so as to cooperate with the corresponding control rod of the male contact 5 during the coupling of these contacts to repel valve 90 toward the opposite end of the inner chamber of the contact body and thus unplug the contact in order to establish the fluidic connection.
A shoulder 98 is formed at the level of the junction between cylindrical skirt 87 and the part 85, shoulder 98 serving as a stop for compression spring 47 mounted inside inner recess 89 of skirt 87.
In uncoupled position, as shown in FIG. 1, spring 47 compresses the pressure face of the closure cone 86 on the inner washer 65 which is in turn flattened against the bottom 78 of inner chamber 66, thereby establishing the self-plugging of fluidic contact 3 in uncoupled position. The action of the compression spring 47 is supplemented by the trust due to the pressure of the heat-carrying fluid.
The inner washer 65 is, for example, a toric gasket made of an elastomer such as nitrile, fluorocarbon, or silicone, this material being capable of withstanding chemical attack of the various types of heat-carrying fluids. Gasket 65 is placed in a groove 80 provided against the bottom 78 of inner chamber 66 of the contact body, in order to avoid being displaced inside the said recess and producing surges or "hammer" in the channels circulating the heat-carrying fluid. Preferably, as shown in FIG. 1, this groove is obtained with the aid of a shoulder 82 formed from the wall of inner chamber 66, the diameter of the top of shoulder 82 being very slightly greater than that of the outer contour of part 85 of the valve. Thus, during the uncoupling operation, the choking of the passage of the fluid generated by the top of the shoulder and the outer contour of part 85 which is then at the same level creates, at the beginning of the self-plugging of the fluidic contact, a drop in pressure of the fluid just before washer 65 is compressed by the closure cone 86 of the valve and establishes the leakproof plugging of the contact. This pressure drop created during the phase of self-plugging of the contact enhances the efficiency and the life of the washer 65. To facilitate the emplacement of washer 65 in groove 80 as the fluidic contact is being made, the shoulder of the groove preferably has an engagement bevel 84 on the side of the shoulder opposite the wall of the groove. Note that in coupled position, as shown in FIG. 2, the shoulder of the groove causes no disturbance in the circulation of the heat-carrying fluid.
The end of the contact body opposite female tip 69 is embedded in a recess 56 of a coupling 50 insuring the fluidic connection of contact 3 with the channel network of the card with fluid circulation. In the example shown in FIG. 1, this embedment is obtained by force-fitting contact body 68 into coupling 50, the facing diameters of the two elements being designed for a tight fit. To gurantee the tightness of the bond between coupling 50 and contact body 68, an annular gasket 62 is placed at the bottom of recess 56 of coupling 50. Gasket 62 is compressed by the end 67 of contact body 68. The compression of gasket 62 is obtained during the operation of force-fitting of body 68 into coupling 50 and maintained by the strong forces of retention of the fit. This tightness can likewise be obtained by an intermetallic sealing bond 63, 64 as shown in FIG. 3. The tightness and the attachment of coupling 50 on contact body 68 can also be produced by operations of gluing, brazing or shrink-fitting.
In the embodiment shown, coupling 50 appears in the form of a parallelopipedic block, of which one face 55 is pierced with a stepped hole not opening on the rear face. This stepped hole is composed of the embedment recess 56 of the same diameter as the outer contour of the contact body 68 and of an inner conduit 52 which is concentric to recess 56 and has a diameter slightly smaller than the inner diameter of spring 47, so that the shoulder between the inner conduit and the recess forms a stop for the end of the said spring and of gasket 62.
One of the faces perpendicular to face 55, namely face 58, which rests on card 1, is pierced with a hole 51 that only partially extends through the coupling, so that hole 51 and the inner conduit 52 will be secant and open into one another. This face 58 is likewise pierced with two tapped holes 33 and 34 situated on either side of hole 51. These tapped holes 33 and 34 are used for the attachment of coupling 50 on printed card 1 as shown in FIGS. 1 and 2. Moreover, face 58 is equipped with an annular groove 42 concentric to hole 51 which serves as an accommodation for an annular gasket 37 insuring a seal between coupling 50 of fluidic contact 3 and the end 51 of the network of channels of card 1 with circulation of fluid.
As already mentioned, the outer contour of female tip 69 has a diameter slightly smaller than that of the outer contour of contact body 68. The two outer contours join by means of a stop face 77 whose plane is perpendicular to the main axis. When the contact body has been fitted into coupling 50, the part of length "l" of the outer contour of the contact body situated between stop faces 77 and 55 is used to place a retention clip 143, to lock fluidic contact 3 in the opening 135 of insulation 130 of connector 2. As shown in FIG. 4, this retention clip appears in the form of a thin elastic tube of length "l", slit along one generatrix 143" and having on its perimeter several retention tabs 143', projecting and elastically deformable. The clip is immobilized in translation on contact body 68 by the stop faces 77 and 55.
Reference is now made to the male fluidic contact 5 shown on the right-hand side of FIGS. 1 and 2. This male contact is constituted by a contact body 68' of cylindrical shape which is prolonged by a male tip 101 appearing in the form of a metal tube equipped on its outer surface with a groove 107 serving as a recess for a washer 125. The diameter of the outer contour of male tip 101 is very slightly less than that of cavity 72 of female tip 69 of the female contact. The outer diameter of gasket 125 mounted in its recess is very slightly larger than that of cavity 72 so as to be compressed on its perimeter when it is engaged in the latter and thus insures the sealing of the fluidic connection. Furthermore, the end of male tip 101 preferably has an entry bevel 106. Entry bevel 106 cooperates with round portion 74 to facilitate the engagement of male tip 101 in cavity 72 of female contact 3. Moreover, the diameter of the hole 76' in male tip 101 is equal or close to the diameter of communicating hole 76 in female tip 60 to permit the passage of the heat-carrying fluid along a section that is substantially constant through the fluidic connection.
The length of male tip 101 separating the front face 105 thereof and the stop face 102 is substantially equal to that of the depth of inner cavity 72 of female tip 69.
The self-plugging device contained in the inner chamber 66' of the contact body 68' of male contact 5 of receptacle 4 is identical to that of female contact 3 of plug 2. Consequently, it will not be described herein and the same elements will bear the same references with a prime. Furthermore, the outer contour of contact body 68' with the clip locking contact 5 in opening 135' of receptacle 4 is identical to that of contact 3 of plug 2 except that one end of the clip presses on the pressure face 109 of contact body 5 instead of pressure face 55 of coupling 50 for contact 3 of plug 2.
The fluidic connection of contact 5 of the receptacle differs from that of contact 3 of the plug by the fact that contact 5 is directly connected to the device supplying heat-carrying fluid in the electronic equipment. Thus contact body 68' is prolonged, on the side opposite that of the male tip, by a connecting sleeve 110 whose outer contour 111 is larger than the outer contour 79' of contact body 68'. The outer contours 111 and 79' are connected by a pressure face 109 perpendicular to the axis of the contact body. During the assembly, this face 109 comes to press on the rear face 134' of the insulation of receptacle 4. Sleeve 111 has an inner cavity 112 communicating with inner chamber 66' of the contact body and in its prolongation. Cavity 112 terminates at the end of the contact body. The diameter of cavity 112 which has a tapped thread 114, is larger than that of the inner chamber 66'. Cavity 112 receives the coupling 120 of the fluid supply system. The latter appears in the form of a tube equipped with a thread 116 which is screwed into tapping 114 until collar 119 of coupling 120 begins to compress an annular packing 124 inserted between itself and the end 113 of sleeve 111. Coupling 120 has a bore 117 whose diameter is slightly smaller than the inner diameter of compression spring 47'. The front face 118 of coupling 120 severs as a support for the terminal turn of spring 47'.
FIG. 1 shows a sectional view of the fluidic connection system in uncoupled position. Note that in this case the pressure faces 92 and 92' of the control rods of the valves of the fluidic contacts are preferably set back relative to the ends of the latter, that is to say, respectively relative to the protective round 74 of the female tip of the female contact and to the front face of male tip 101 of the male contact. As a matter of fact, if, in the uncoupled position, one of the fluidic contacts exhibits a valve rod protruding relative to the end of the contact, the guarantee of self-plugging of the latter is not well assured because the control rod risks being accidentally brought into contact with an object and thus cause a leakage of heat-carrying fluid. In the case of the example described, the control rods which remain in the interior of cavities 72 and 72' are naturally protected from such a risk. Moreover, if the two control rods of the male and female contacts are protuberant in the uncoupled state, it is not possible to uncouple them without causing leakages of fluid. Consequently, the control rods are set back by a length "a" relative to the protective rounding 74 of the male contact and by a length "b" relative to the front face 105 of the male contact.
In order to make the connection and disconnection without leakage of heat-carrying fluid, it is necessary that the washer 125 be able to slide on the inner contour of the inner cavity 72 before the pressure faces 92, 92' of the control rods come into contact at the moment of coupling. This implies that:
(1) "a" is greater than "c" if the face 92' is situated between the face 105 and the plane of symmetry of the gasket 125, "c" being the distance between this plane of symmetry and the face 92'.
(2) or that the face 92' is set back relative to the plane of symmetry of gasket 125.
FIG. 2 shows a sectional view of the entire fluidic connection system in coupled position. The essential condition, if the fluidic connection is to be insured in coupled position, is that the closure cones 86, 86' of the valves 90, 90' no longer press on the washers 65, 65'. Now, as a function of the conditions of pressure and the direction of circulation of the heat-carrying fluid, as well as of the respective forces of compression of springs 47 and 47', the kinetics of the self-plugging device of the female and male fluidic contacts can be done in different ways at the moment of connection of the latter.
Thus, either the two valves 90 and 90' are opened conjointly as soon as their control rods press on one another, and then the fluidic connection is immediately insured, or one of the two valves 90 or 90' first opens completely until its receptacle 99 presses on the bottom of this recess, then the opening of the second begins. Then, at this moment only, the fluidic connection is made.
The penetration of male contact 5 into female contact 3 is limited by the meeting of the front faces 133 and 133' of the respective insulations of the plug and of the receptacle of the electrical connector. Thus to insure the fluidic connection in all the figure cases, the algerbraic sum "d+e" must be larger than the highest of the two values "f", "g" in which:
"d" is the distance between faces 92 and 133 in the uncoupled state,
"e" is the distance between faces 92' and 133' in the uncoupled state.
("d" or "e" will have a positive sign when the pressure face of the control rod of the valve projects beyond the plane of the front face of the insulation, and a negative sign when it is retracted relative to the latter.),
"f" is the distance between receptacle 99 of the valve and bottom 57 in the uncoupled state, and
"g" is the distance between the receptacle 99' of the valve and the face 118 in the uncoupled state.
("f", "g" having a positive sign.)
The difference Δ between the algebraic sum "d+e" and the higher of the two values "f" and "g" constitutes what is called the plug-in security of the connector.
It expresses the maximum spread Δ between the two insulators 133 and 133' for which the fluidic connection is assured. The distances a, b, c, d, e, f, and g will preferably be determined so that the plug-in security Δ of the fluidic connection will be at least equal to that of the other contacts of the electrical connector.
FIGS. 5 to 7 show a number of variations of embodiment of the connection of fluidic contact 3 on the daughter card 1. In FIG. 5, the mechanical attachment of coupling 50 of fluidic contact 3 on card 1 with fluid circulation is embodied by means of a hollow screw 160. This hollow screw 160 is mounted in orifice 51 with a tapped thread 167 of coupling 50 and is situated in the passage of the heat-carrying fluid. As a result, the threaded rod 165 of screw 160 has a hole 162 with axis 40 that terminates in inner conduit 52 of coupling 50 and with the end 15 of the channel network of the card by means of holes 161 with axes perpendicular to axis 40 and pierced in threaded rod 165 under the head 163 of the screw. Moreover, the bottom of channel 17 of the card is pierced with a hole 168 for the passage of screw 160 and as a result it is necessary to place a gasket 169 in a shoulder 164 of head 163 to insure the sealing of the device. Consequently, hollow screw 160 ensures securing of coupling 50 on card 1. As a result one single screw suffices to ensure the attachment with a guarantee of an effective seal between coupling 50 and card 1 because the pressure is thus distributed uniformly over the perimeter of the gaskets.
This variation has the following advantages:
reduction in the number of attachment screws and consequently, the simplification of coupling 50 and reduction of its volume, which increases the useful surface for the implanation of components on the card, and
simplification of the network of channels of the plate of the heat drain 10 because the ends 15 and 16 can be situated directly in the prolongation of the channels.
FIG. 6 shows a sectional view of a system of fluidic connection similar to that in FIG. 5, in which a fluted screw 170 is used in place of screw 160. In this case the passage of the heat-carrying fluid between end 15 of the network of channels in the card and inner conduit 52 of coupling 50 is made through the flutings 172 cut longitudinally on the outside of the threaded shaft of fluted screw 170 instead of through the inner hole 162 in hollow screw 160.
FIG. 7 shows in section a view of a system of fluidic connection coupled on the transverse edge 27 of card 1. This variation is used in particular when the output terminals of the electrical contacts of the plug are soldered flat on either side of card 1 so that the plane of the latter proves to be substantially in the prolongation of the plane of symmetry of plug 2 instead of being offset on one side or the other as shown in the other figures. In this case coupling 50 has a slot 187 in the axis of the fluidic contact 3. Coupling 50 is pierced along an axis perpendicularly to slot 187. The hole 191 in the upper part of the coupling terminates on the upper face in a beveled orifice 193. The hole 192 with the same axis as hole 191 terminates on the lower face in a beveled orifice 194. End 15 of the channel network of card 1 has an opening 196 terminating on the transverse edge 27 of the card. In this variation, no hole communicating with end 15 is pierced in closure plate 11. A guide hole 197 is pierced in the prolongation of opening 198, but outside the network of channels. The connection of card 1 on the plug of connector 2 is operated as follows. A flat gasket 195 is introduced at the bottom of slot 187 of coupling 50 so that the hole of the gasket will be face to face with inner conduit 52. Card 1 is engaged simultaneously in slot 187 of coupling 50 and between the two rows of output terminals of the electrical contacts. A cone-head screw 180 passing through holes 191, 197 and 192 is introduced into coupling 50. The diameter of the smooth part 184 of the threaded shaft 185 of screw 180 is equal to the diameter of hole 197 in the card and smaller than the diameter of holes 191 and 192.
At this moment, the axis 196 of screw 180 is offset toward the rear face of coupling 50 relative to the axis of holes 191 and 192. A conical nut 181 is then screwed on threaded shaft 185 of screw 180. Under the influence of the tightening of this nut, the pressure cone 186 of the head of screw 183 and the pressure cone 182 of nut 181 cooperate respectively with orifices 193 and 194 to displace card 1 in the direction of the arrow f toward the bottom of slot 187 in coupling 50. When the complete tightening of the screw and the nut is achieved, axis 196 of screw 180 coincides with the axis of holes 191 and 192 and gasket 195 is compressed to insure the seal of the coupling of fluidic contact on card 1.
There will now be described, with reference to FIGS. 8 to 10, some variations of embodiments of the self-plugging device, the other parts of the fluidic contacts being substantially similar to those shown in FIGS. 1 and 2.
In the embodiment in FIG. 8, the valve is constituted by a solid piece 900 equipped at the rear opposite control rod 91 with a guide shaft 901 sliding in a journal 902 provided in the interior of inner chamber 66 of contact body 68. The journal is equipped with longitudinal orifices for the passage of the fluid. In this case compressing spring 47 is mounted around the guide shaft between journal 902 and the rear face of solid piece 900. Moreover, the coupling 50' permitting the connection of fluidic contact 3 with the card has a form slightly different from that of coupling 50 in FIGS. 1 and 2.
The contact body 68 is no longer inserted in a recess 56 terminating on one face of coupling 50 as in the embodiment in FIGS. 1 and 2, but the contact body 68 has, at its rear ends, a tapped internal recess 67 larger in diameter than inner recess 66 in order to be screwed on a threaded coupling part 54 replacing the recess 56. In this embodiment, the same plug devices are provided in the male fluidic contact and the female fluidic contact, as will clearly be seen in FIG. 8, with the exception of the fact that the control rods of the male and female contacts are unequal but answer to the algebraic sum "d+e" mentioned above.
FIG. 9 shows another variation of the plug device. In this figure, the male fluidic contact is mounted in an opening 135 of plug 2 of the electrical connector coupled on the daughter card while the female fluidic contact is mounted on receptacle 4 of the said connector. The plug device of the male fluidic contact is constituted by a ball 910 actuated by a compression spring 470 preferably constituted by a conical spring for a better seating of the ball. This ball serves as self-plugging valve as it compresses an annular washer 65. Moreover, compression spring 470 is positioned between the rear face of the ball and a shoulder 471 embodied by a cylindrical tube which is positioned in the interior of the inner chamber of the contact body and pressing against the bottom of recess 56 in coupling 50 which, in this embodiment, is identical to the coupling in FIG. 1. Moreover, the female fluidic contact is equipped with an external-flow valve substantially identical to the valve described in reference to FIG. 8, thus this valve will not be described in detail. Nevertheless, the toric gasket 65 is replaced by a gasket 65" mounted on the front face of valve 900. In this case the ball is not equipped with a control rod, hence the length of the control rod of the external-flow valve will have a length equal to "d+e".
Other types of plug devices can be envisaged. Thus, so-called slide valves can be envisaged.
Such a valve is shown, for example, in FIG. 10.
In this case contact body 68 of female fluidic contact 3 has a modified form. As a matter of fact, inner chamber 66 has, on the side of the female tip, a part 66" of larger diameter for the passage of the heat-carrying fluid when the two contacts are coupled. Moreover, the diameter of inner cavity 72 of the female tip is identical to the diameter of the rear part of the inner chamber. As shown in the figure, two washers 650, 651 are provided in grooves formed respectively in the rear part of inner chamber 66 and inner cavity 72. In this case the value is constituted by a cylindrical piece 920 closed at one end, whose outer diameter corresponds to the inner diameter of the rear part of inner chamber 66 and of the inner cavity of the tip so as to slide inside the body 68 and the female tip.
Furthermore, piece 920 is equipped with at least one orifice 921 for passage of the heat-carrying fluid. It also has, at its rear end a bore 922 of larger diameter receiving a compression spring 47 which, in uncoupled position, urges the piece projecting into the female tip so that the fluid cannot flow out of part 66". The rear end of spring 47 presses against a ring provided in the bottom of recess 56 of coupling 50. The orifices 921 are positioned on the cylindrical piece so that in coupled position they coincide with part 66" as shown in FIG. 10.
Furthermore, piece 920 is prolonged by a control rod 91. The contact body 68 is mounted in a coupling 50 similar to coupling 50 in FIG. 1.
The right-hand part of FIG. 10 shows a male fluidic contact 5 equipped with a slide valve cooperating with the slide valve of the female fluidic contact. In this case the valve is constituted by a cylindrical piece 920'; closed at one end and equipped on its perimeter close to this end with at least one orifice 921', this piece being urged, in uncoupled position, by a spring 47', toward the front end of the male tip which is then constituted by a cylindrical piece 101' equipped at its front end with a hole whose diameter corresponds to the diameter of rod 91. Furthermore, the male tip 101' has, on its perimeter, at least one orifice 101" whose position corresponds, when the connector is coupled, to the position of orifice 921' of the valve.
Thus, during the coupling, rod 91 cooperates with the end of piece 920' to repel valves 920 and 920' so that the orifices 921' and 101' will be made to correspond and so that these orifices and so orifices 921 will be in communication with part 66" to permit the passage of the fluid as can clearly be seen in FIG. 10.
Various modifications can be brought to the form of the contacts, couplings or valves without departing from the scope of the present invention. | Miniature fluidic connector that fits into an electrical connector for printed circuit boards with a built-in heat exchanger. Male and female fluidic contacts are mountable in openings in the plug or receptacle of the electrical connector and have respective tips to couple with each other. Upon coupling, the ends of the openings of the plug and the receptacle of the electrical connector are substantially in pressure contact against each other. Preferably, the male and female fluidic contacts have inner chambers adapted to receive self-plugging devices. |
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