US20060225434A1 - Cryocooler assembly with screened regenerator - Google Patents
Cryocooler assembly with screened regenerator Download PDFInfo
- Publication number
- US20060225434A1 US20060225434A1 US11/102,700 US10270005A US2006225434A1 US 20060225434 A1 US20060225434 A1 US 20060225434A1 US 10270005 A US10270005 A US 10270005A US 2006225434 A1 US2006225434 A1 US 2006225434A1
- Authority
- US
- United States
- Prior art keywords
- regenerator
- screens
- cryocooler
- heat transfer
- cryocooler assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/14—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
- F25B9/145—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle pulse-tube cycle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D17/00—Regenerative heat-exchange apparatus in which a stationary intermediate heat-transfer medium or body is contacted successively by each heat-exchange medium, e.g. using granular particles
- F28D17/02—Regenerative heat-exchange apparatus in which a stationary intermediate heat-transfer medium or body is contacted successively by each heat-exchange medium, e.g. using granular particles using rigid bodies, e.g. of porous material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/003—Gas cycle refrigeration machines characterised by construction or composition of the regenerator
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/14—Compression machines, plants or systems characterised by the cycle used
- F25B2309/1413—Pulse-tube cycles characterised by performance, geometry or theory
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/14—Compression machines, plants or systems characterised by the cycle used
- F25B2309/1415—Pulse-tube cycles characterised by regenerator details
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/14—Compression machines, plants or systems characterised by the cycle used
- F25B2309/1421—Pulse-tube cycles characterised by details not otherwise provided for
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/14—Compression machines, plants or systems characterised by the cycle used
- F25B2309/1424—Pulse tubes with basic schematic including an orifice and a reservoir
Abstract
A cryocooler assembly having a regenerator employing a plurality of high heat capacity screens positioned perpendicular to the regenerator longitudinal axis and in a sufficient linear density to serve as heat transfer media and also to serve as buffer structures to keep worm holes within particulate heat transfer media from forming and to reduce agglomeration of particles within the regenerator.
Description
- This invention relates generally to low temperature or cryogenic refrigeration and, more particularly, to cryocoolers for the generation of such cryogenic refrigeration.
- A recent significant advancement in the field of generating low temperature refrigeration is the pulse tube and other cryocooler systems wherein pulse energy is converted to refrigeration using an oscillating gas. Such systems can generate refrigeration to very low levels sufficient, for example, to liquefy helium.
- One problem with conventional cryocooler systems is the loss of effective load heat capacity and flow uniformity and the resulting heat transfer maldistribution in the regenerator portion of the cryocooler which leads to operational inefficiency. These problems are particularly troublesome when the cryocooler is operated to provide very low temperature refrigeration such as below 40K.
- A cryocooler assembly comprising a pressure wave generator, a regenerator and a thermal buffer volume wherein the regenerator contains heat transfer media comprising a plurality of screens oriented perpendicular to the longitudinal axis of the regenerator, said screens being comprised of or coated with high heat capacity material or alloy.
- As used herein the term “screen” means a thin plate with periodic openings such as mesh, perforated plate, wire mesh or corrugated dimpled plate used for transferring heat from and to gas while providing uniform flow through its openings.
- As used herein the term “high heat capacity material” means a chemical element or compound that has a higher volumetric or mass heat capacity than steel at temperatures below 100K. Some examples include lead, some copper alloys, and lanthanide series materials.
- As used herein the term “high heat capacity alloy” means a homogeneous mixture, solid solution or heterogeneous mixture comprising at least one high heat capacity material.
- As used herein the term “pressure wave generator” means an electromechanical, mechanical, or thermoacoustic device that produces pressure waves in the form of acoustic energy.
- As used herein the term “longitudinal axis” means an imaginary line running through a regenerator in the direction of the gas flow.
- As used herein the term “regenerator” means a thermal device containing heat transfer media which has good thermal capacity to cool incoming warm gas and warm returning cold gas via direct heat transfer with the heat transfer media.
- As used herein the term “thermal buffer volume” means a cryocooler component separate from the regenerator, proximate a cold heat exchanger and spanning a temperature range from the coldest to the warmer heat rejection temperature.
- As used herein the term “indirect heat exchange” means the bringing of fluids into heat exchange relation without any physical contact or intermixing of the fluids with each other.
- As used herein the term “direct heat exchange” means the transfer of refrigeration through contact of cooling and heating entities.
- As used herein the term “electroplated screen” means a base screen substrate which is covered by a high heat capacity material or alloy via electroplating and/or another thin film deposition means.
-
FIG. 1 is a representation of one preferred cryocooler assembly of this invention wherein the cryocooler is a pulse tube type cryocooler. -
FIG. 2 is a plan view of one preferred embodiment of a screen type for use in the practice of this invention. -
FIG. 3 is a plan view of another preferred embodiment of a screen type for use in the practice of this invention. -
FIG. 4 is a plan view of another preferred embodiment of a screen type for use in the practice of this invention. -
FIG. 5 is a cross sectional representational illustration of the screen interlayer embodiment of the present invention. - The invention will be described in greater detail with reference to the Drawings. Referring now to
FIG. 1 , pressure wave generator 9, which may be a compressor driven by a linear or rotary motor, generates a pulsing gas to drive a cryocooler such as the pulse tube cryocooler illustrated inFIG. 1 . The pulsing working gas pulses within the pressure wave pathway which comprises the pressure wave generator, a regenerator and a thermal buffer volume. In the pulse tube type cryocooler illustrated inFIG. 1 , the pressure wave pathway also includes a reservoir downstream of the thermal buffer volume. Typically the working gas comprises helium. Other gases which may be used as working gas in the practice of this invention include neon, argon, xenon, nitrogen, air, hydrogen and methane. Mixtures of two or more such gases may also be used as the working gas. - The pulsing working gas applies a pulse to the hot end of the
regenerator 10 thereby generating an oscillating working gas and initiating the first part of the pulse tube sequence. The pulse serves to compress the working gas producing hot compressed working gas at the hot end of theregenerator 10. The hot working gas is cooled, preferably by indirect heat exchange withheat transfer fluid hot heat exchanger 40 to cool the compressed working gas of the heat of compression.Heat exchanger 40 is also the heat sink for the heat pumped from the refrigeration load against the temperature gradient by theregenerator 10 as a result of the pressure-volume work generated by the pressure wave generator. -
Regenerator 10 contains heat transfer media as will be more fully described below. The pulsing or oscillating working gas is cooled inregenerator 10 by direct heat exchange with cold heat transfer media to produce cold pulse tube working gas. - Thermal buffer volume or
tube 16, which in the arrangement illustrated inFIG. 1 is a pulse tube, andregenerator 10 are in flow communication. The flow communication includescold heat exchanger 14. The cold working gas passes inline 17 tocold heat exchanger 14 and inline 18 fromcold heat exchanger 14 to the cold end ofthermal buffer tube 16. Withincold heat exchanger 14 the cold working gas is warmed by indirect heat exchange with a refrigeration load thereby providing refrigeration to the refrigeration load. InFIG. 1 , the refrigeration load is represented bystream 47 which is passed tocold heat exchanger 14 and which emerges therefrom asstream 46. One example of a refrigeration load is for use in a magnetic resonance imaging system. Another example of a refrigeration load is for use in high temperature superconductivity. - The working gas is passed from the
regenerator 10 tothermal buffer tube 16 at the cold end. As the working gas passes intothermal buffer volume 16, it compresses gas in the thermal buffer volume or tube and forces some of the gas throughwarm heat exchanger 43 andorifice 20 inline 19 into thereservoir 22. Flow stops when pressures in both the thermal buffer tube and the reservoir are equalized. - Cooling fluid is passed in
line 44 towarm heat exchanger 43 wherein it is warmed or vaporized by indirect heat exchange with the working gas, thus serving as a heat sink to cool the compressed working gas. The resulting warmed or vaporized cooling fluid is withdrawn fromheat exchanger 43 inline 45. - In the low pressure point of the pulsing sequence, the working gas within the thermal buffer tube expands and thus cools, and the flow is reversed from the now relatively
higher pressure reservoir 22 into thethermal buffer tube 16. The cold working gas is pushed into thecold heat exchanger 14 and back towards the warm end of the regenerator while providing refrigeration atheat exchanger 14 and cooling the regenerator heat transfer media for the next pulsing sequence. Orifice 20 andreservoir 22 are employed to maintain the pressure and flow waves in phase so that the thermal buffer tube generates net refrigeration during the compression and the expansion cycles in the cold end ofthermal buffer tube 16. Other means for maintaining the pressure and flow waves in phase which may be used in the practice of this invention include inertance tube and orifice, expander, linear alternator, bellows arrangements, and a work recovery line connected back to the compressor with a mass flux suppressor. In the expansion sequence, the working gas expands to produce working gas at the cold end of thethermal buffer tube 16. The expanded gas reverses its direction such that it flows from the thermal buffer tube towardregenerator 10. The relatively higher pressure gas in the reservoir flows throughvalve 20 to the warm end of thethermal buffer tube 16. In summary,thermal buffer tube 16 rejects the remainder of pressure-volume work generated by the compression as heat intowarm heat exchanger 43. - The expanded working gas emerging from
heat exchanger 14 is passed toregenerator 10 wherein it directly contacts the heat transfer media within the regenerator to produce the aforesaid cold heat transfer media, thereby completing the second part of the pulse tube refrigeration sequence and putting the regenerator into condition for the first part of a subsequent pulse tube refrigeration sequence. - Conventional heat transfer media within the regenerator, such as particulate material, tend to promote flow maldistribution via worm hole and agglomerate formation in these materials. In the practice of this invention the heat transfer media is comprised of a plurality of screens oriented perpendicular to the longitudinal axis of the regenerator. The screens act as heat transfer media per se, and also serve as buffer structures, as in the preferred embodiments illustrated in
FIG. 3-5 , to combat worm hole formation and agglomeration when particles are also employed as heat transfer media within the regenerator. Preferably the screens which are employed in the practice of this invention are comprised of steel, copper, oxygen-free copper, copper bronze, phosphorous copper, etc. - In one preferred embodiment of the invention illustrated in
FIG. 2 , thebase support screen 61 is electroplated with high heat capacity material or alloy such as lead orrare earth 62 to form screens 60. The screen bed within the regenerator produced by the use of such preferred screens exhibits optimum porosity and volumetric heat capacity, and also allows transverse equalization of temperatures. For a cryocooler operating at 80K the porosity of such screens may be within 50 to 90% for optimal performance, while a cryocooler operating at 20K could be optimized at a screen porosity within the range of from 10 to 50 percent. - In another preferred embodiment of the invention illustrated in simplified form in
FIGS. 3 and 4 , the steel, copper bronze or oxygen-free copper screens 71 are made with openings large enough to acceptparticles 72 made of high heat capacity material or alloys such as lead or rare earth within their matrices. The addition of the particles within the screen matrix will provide higher heat transfer and high heat capacity at lower temperatures. The coarse screens will suppress particle agglomeration and minimize longitudinal heat conduction. The coarse screens filled with loose particles could be supported at both ends (top and bottom) by veryfine screens 77. Essentially, these fine screens will contain the particles in the regenerator bed assembly. - In another preferred embodiment of the invention, which is illustrated in
FIG. 5 , screens are installed in theregenerator 10 ininterlayers 82 perpendicular to the longitudinal axis orgas flow 84 to holdheat transfer particles 85 inlayers 83 between the screens. This grading or layering of the screens and particulate material in alternating sequence allows better optimization of the regenerator bed thus resulting in better cryocooler performance. The screen-interlayers can be made of multiple diffusion-bonded or loose steel, copper bronze or oxygen-free copper screens. The diffusion-bonded screens can be made to various thicknesses for adequate support. Oscillating flow can be detrimental to screen integrity. Therefore screens must be adequately designed to support the particulate bed materials in operation. A reduced number of screens can be used with a reinforcing plate like structure to ensure larger ratios of rare earth to interlayer material, while maintaining structure integrity. Additionally, the screen interlayers will allow transverse equalization of temperatures and allows a graded regenerator bed. For example lead particles could be used at regenerator temperature zones of 70 to 30K and rare earth materials could be used at temperatures below 30K. There could be more than two different bed materials within the regenerator. The bed could also be graded with particle diameters where smaller diameter more expensive particles could be used in the colder zones of the regenerator. - Preferably in the practice of this invention screens are positioned within the regenerator in a linear density within the range of from 150 to 600 screens per inch.
- Although the invention has been described in detail with reference to certain preferred embodiments, those skilled in the art will recognize that there are other embodiments of the invention within the spirit and the scope of the claims.
Claims (5)
1. A cryocooler assembly comprising a pressure wave generator, a regenerator and a thermal buffer volume wherein the regenerator contains heat transfer media comprising a plurality of screens oriented perpendicular to the longitudinal axis of the regenerator, said screens being comprised of or coated with high heat capacity material or alloy.
2. The cryocooler assembly of claim 1 wherein the screens are electroplated with high heat capacity material or alloy.
3. The cryocooler assembly of claim 1 further comprising lead or rare earth particles within at least some of the screen matrices.
4. The cryocooler assembly of claim 1 further comprising a plurality of layers of heat transfer particles each such layer positioned between two screens to form a layering of screens and particulate material in alternating sequence.
5. The cryocooler assembly of claim 1 wherein the screens are positioned within the regenerator in a linear density of from 150 to 600 screens per inch.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US11/102,700 US20060225434A1 (en) | 2005-04-11 | 2005-04-11 | Cryocooler assembly with screened regenerator |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US11/102,700 US20060225434A1 (en) | 2005-04-11 | 2005-04-11 | Cryocooler assembly with screened regenerator |
Publications (1)
Publication Number | Publication Date |
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US20060225434A1 true US20060225434A1 (en) | 2006-10-12 |
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ID=37081830
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US11/102,700 Abandoned US20060225434A1 (en) | 2005-04-11 | 2005-04-11 | Cryocooler assembly with screened regenerator |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070119191A1 (en) * | 2005-03-31 | 2007-05-31 | Sumitomo Heavy Industries, Ltd. | Pulse tube cryogenic cooler |
CN101825288A (en) * | 2010-04-27 | 2010-09-08 | 西安交通大学 | Sealing device for boiler rotary heater |
ES2408381A1 (en) * | 2011-10-14 | 2013-06-20 | Consejo Superior De Investigaciones Científicas (Csic) | Regeneration medium suitable for use in heat exchangers and method associated with said medium |
US20140331689A1 (en) * | 2013-05-10 | 2014-11-13 | Bin Wan | Stirling engine regenerator |
US20150192329A1 (en) * | 2014-01-09 | 2015-07-09 | Raytheon Company | Cryocooler regenerator containing one or more carbon-based anisotropic thermal layers |
US20150219366A1 (en) * | 2012-10-22 | 2015-08-06 | Kabushiki Kaisha Toshiba | Cold head, superconducting magnet, examination apparatus, and cryopump |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
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US4874677A (en) * | 1987-11-02 | 1989-10-17 | Veb Hockvakuum Dresden | Matrix material for regenerators |
US5429177A (en) * | 1993-07-09 | 1995-07-04 | Sierra Regenators, Inc. | Foil regenerator |
US5746269A (en) * | 1996-02-08 | 1998-05-05 | Advanced Mobile Telecommunication Technology Inc. | Regenerative heat exchanger |
US6065295A (en) * | 1995-12-15 | 2000-05-23 | Leybold Vakuum Gmbh | Low-temperature refrigerator with cold head and a process for optimizing said cold head for a desired temperature range |
US6640553B1 (en) * | 2002-11-20 | 2003-11-04 | Praxair Technology, Inc. | Pulse tube refrigeration system with tapered work transfer tube |
US20040060303A1 (en) * | 2001-01-17 | 2004-04-01 | Haberbusch Mark S. | Densifier for simultaneous conditioning of two cryogenic liquids |
US20040231340A1 (en) * | 2003-05-23 | 2004-11-25 | Uri Bin-Nun | Low cost high performance laminate matrix |
US20050217280A1 (en) * | 2004-02-23 | 2005-10-06 | Atlas Scientific | Low temperature cryocooler regenerator of ductile intermetallic compounds |
-
2005
- 2005-04-11 US US11/102,700 patent/US20060225434A1/en not_active Abandoned
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4874677A (en) * | 1987-11-02 | 1989-10-17 | Veb Hockvakuum Dresden | Matrix material for regenerators |
US5429177A (en) * | 1993-07-09 | 1995-07-04 | Sierra Regenators, Inc. | Foil regenerator |
US6065295A (en) * | 1995-12-15 | 2000-05-23 | Leybold Vakuum Gmbh | Low-temperature refrigerator with cold head and a process for optimizing said cold head for a desired temperature range |
US5746269A (en) * | 1996-02-08 | 1998-05-05 | Advanced Mobile Telecommunication Technology Inc. | Regenerative heat exchanger |
US20040060303A1 (en) * | 2001-01-17 | 2004-04-01 | Haberbusch Mark S. | Densifier for simultaneous conditioning of two cryogenic liquids |
US6640553B1 (en) * | 2002-11-20 | 2003-11-04 | Praxair Technology, Inc. | Pulse tube refrigeration system with tapered work transfer tube |
US20040231340A1 (en) * | 2003-05-23 | 2004-11-25 | Uri Bin-Nun | Low cost high performance laminate matrix |
US20050217280A1 (en) * | 2004-02-23 | 2005-10-06 | Atlas Scientific | Low temperature cryocooler regenerator of ductile intermetallic compounds |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070119191A1 (en) * | 2005-03-31 | 2007-05-31 | Sumitomo Heavy Industries, Ltd. | Pulse tube cryogenic cooler |
US7600386B2 (en) * | 2005-03-31 | 2009-10-13 | Sumitomo Heavy Industries, Ltd. | Pulse tube cryogenic cooler |
CN101825288A (en) * | 2010-04-27 | 2010-09-08 | 西安交通大学 | Sealing device for boiler rotary heater |
ES2408381A1 (en) * | 2011-10-14 | 2013-06-20 | Consejo Superior De Investigaciones Científicas (Csic) | Regeneration medium suitable for use in heat exchangers and method associated with said medium |
US20150219366A1 (en) * | 2012-10-22 | 2015-08-06 | Kabushiki Kaisha Toshiba | Cold head, superconducting magnet, examination apparatus, and cryopump |
US10753652B2 (en) * | 2012-10-22 | 2020-08-25 | Kabushiki Kaisha Toshiba | Cold head, superconducting magnet, examination apparatus, and cryopump |
US11530846B2 (en) | 2012-10-22 | 2022-12-20 | Kabushiki Kaisha Toshiba | Cold head, superconducting magnet, examination apparatus, and cryopump |
US20140331689A1 (en) * | 2013-05-10 | 2014-11-13 | Bin Wan | Stirling engine regenerator |
US20150192329A1 (en) * | 2014-01-09 | 2015-07-09 | Raytheon Company | Cryocooler regenerator containing one or more carbon-based anisotropic thermal layers |
US9488389B2 (en) * | 2014-01-09 | 2016-11-08 | Raytheon Company | Cryocooler regenerator containing one or more carbon-based anisotropic thermal layers |
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AS | Assignment |
Owner name: PRAXAIR TECHNOLOGY, INC., CONNECTICUT Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ARMAN, BAYRAM;HAMILTON, AL-KHALIQUE S.;ACHARYA, ARUN;REEL/FRAME:016171/0088;SIGNING DATES FROM 20050121 TO 20050404 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |