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(12) United States Patent
Arman et al.
(io) Patent No.: US 6,881,354 B2 (45) Date of Patent: Apr. 19,2005
(21) Appl. No.: 10/201,287
(22) Filed: Jul. 24, 2002
(65) Prior Publication Data
US 2003/0042463 Al Mar. 6, 2003
Related U.S. Application Data
(60) Continuation-in-part of application No. 09/545,670, filed on Apr. 7, 2000, now Pat. No. 6,426,019, which is a division of application No. 09/222,809, filed on Dec. 30,1998, now Pat. No. 5,076,372.
(51) Int. C I. C09K 5/04
(52) U.S. CI 252/67; 62/606
(58) Field of Search 252/67, 68
(56) References Cited
U.S. PATENT DOCUMENTS
3,992,167 A 11/1976 Beddome 62/18
5,157,925 A 10/1992 Denton et al 62/11
5,425,890 A 6/1995 Yudin et al 252/67
5,441,658 A 8/1995 Boyarsky et al 252/67
5,502,972 A 4/1996 Howard et al 62/23
5,579,654 A 12/1996 Longsworth et al 62/511
5,607,616 A 3/1997 Minor et al 252/67
5,622,644 A 4/1997 Stevenson et al 252/67
5,650,089 A 7/1997 Gage et al 252/67
5,687,574 A 11/1997 Longsworth et al 62/55.5
5,729,993 A 3/1998 Boiarski et al 62/175
5,736,063 A 4/1998 Richard et al 252/67
5,785,741 A 7/1998 Li et al 96/4
5,792,523 A 8/1998 McHugh, III 428/34
5,976,222 A 11/1999 Yang et al 95/45
6,426,019 Bl * 7/2002 Acharya et al.
FOREIGN PATENT DOCUMENTS
EP 430169 11/1990
GB 2291884 7/1995
WO WO 94/17153 * 8/1994
WO WO 98/08912 * 3/1998
Vorster et al, "Wet Compression vs dry compression in heat pumps working with pure refrigerants or non-azeotropic binary mixtures for different heating applications" International Journal of Refrigeration, 23 (4) , year 2000, pp 292-311.*
Bobbo et al., "Composition Shift of the Mixtures R-125/ 236fa(49./50.6) and R-509A" PRoceedings of the International Refrigeration Conference at Perdue, 1th , Jul. 14-17, 1998, pp 87-92.*
* cited by examiner
Primary Examiner—Margaret Einsmann
(74) Attorney, Agent, or Firm—Stanley Ktorides
Multicomponent refrigerant fluids for generating refrigeration, especially over a wide temperature range including cryogenic temperatures, which are advantageous over conventional refrigerant fluids especially for certain applications, and which are non-toxic, non-flammable and low or non-ozone-depleting and preferably are maintained in variable load form through compression, cooling, expansion and warming steps in a refrigeration cycle.
6 Claims, 2 Drawing Sheets
FLUIDS FOR LOW AND CRYOGENIC
This is a Continuation-in-Part of prior U.S. application(s) 5 Ser. No. 09/545,670, Filing Date: Apr. 7, 2000 now U.S. Pat. No. 6,426,019 and which in turn is a Division of application Ser. No. 09/222,809, Filing Date Dec. 30, 1998 now U.S. Pat. No. 5,076,372.
This invention relates generally to refrigeration and, more particularly, to the use of multiple component refrigerant fluids useful for generating refrigeration. The invention is particularly useful for providing refrigeration down to cryogenic temperatures.
Refrigeration is conventionally generated by compressing 20 and then expanding a refrigerant fluid within a refrigeration circuit. Well known examples of such conventional systems include refrigerators and air conditioners. Typically the refrigerant is a single component fluid which undergoes a phase change at a required temperature from a liquid to a gas 25 thus making its latent heat of vaporization available for cooling purposes. The efficiency of the conventional system can be improved by using a multiple component fluid as the refrigerant which can provide variable amounts of refrigeration over a required temperature range. However, known 30 multiple component fluid refrigeration cycles cannot effectively provide refrigeration over a large temperature range down to colder cryogenic temperatures. Moreover, most well known refrigerant fluids are toxic, flammable and/or ozone depleting. 35
Accordingly it is an object of this invention to provide multiple component refrigerant fluids which are useful for providing refrigeration down to cryogenic temperatures.
SUMMARY OF THE INVENTION 40
The above and other objects, which will become apparent to those skilled in the art upon a reading of this disclosure, are attained by the present invention, which is described in detail below. 45
As used herein the term "variable load refrigerant" means a mixture of two or more components in proportions such that the liquid phase of those components undergoes a continuous and increasing temperature change between the bubble point and the dew point of the mixture. The bubble 50 point of the mixture is the temperature, at a given pressure, wherein the mixture is all in the liquid phase but addition of heat will initiate formation of a vapor phase in equilibrium with the liquid phase. The dew point of the mixture is the temperature, at a given pressure, wherein the mixture is all 55 in the vapor phase but extraction of heat will initiate formation of a liquid phase in equilibrium with the vapor phase. Hence, the temperature region between the bubble point and the dew point of the mixture is the region wherein both liquid and vapor phases coexist in equilibrium. In the go practice of this invention the temperature differences between the bubble point and the dew point for the variable load refrigerant is at least 10° K, preferably at least 20° K and most preferably at least 50° K.
As used herein the term "fluorocarbon" means one of the 65 following: tetrafiuoromethane (CF4), perfluoroethane (C2F6), perfluoropropane (C3F8), perfluorobutane (C4F10),
perffuoropentane (C5F12), perfluoroethene (C2F4), perfluoropropene (C3F6), perfluorobutene (C4F8), perfluoropentene (C5F10), perfluorohexane (C6F14), hexafluorocyclopropane (cyclo-C3F6) and octafluorocyclobutane (cyclo-C4F8).
As used herein the term "hydrofluorocarbon" means one of the following: fluoroform (CHF3), pentafluoroethane (C2HF5), tetrafluoroethane (C2H2F4), heptafluoropropane (C3HF7), hexafluoropropane (C3H2F6), pentafluoropropane (C3H3 F5), tetrafluoropropane (C3H4F4), nonafluorobutane (C4HF9), octafluorobutane (C4H2F8), undecafluoropentane (cjhfjj), decafluoropentane (C5H2F10), methyl fluoride (CH3F), difluoromethane (CH2F2), ethyl fluoride (C2H5F), difluoroethane (C2H4F2), trifluoroethane (C2H3F3), difluoroethene (C2H2F2), trifluoroethene (C2HF3), fluoroethene (C2H3F), pentafluoropropene (C3HF5), tetrafluoropropene (C3H2F4) trifluoropropene (C3H3F3), difluoropropene (C3H4F2), heptafluorobutene (C4HF7), hexafluorobutene (C4H2F6) and nonafluoropentene (C5HF9)
As used herein the term "hydrochlorofluorocarbon" means one of the following: chlorodifiuoromethane (CHC1F2), chlorofiuoromethane (CH2C1F), chloromethane (CH 3C1), dichlorofluoromethane (CHC12F), chlorotetrafluoroethane (C2HC1F4), chlorotrifluoroethane (C2H2C1F3), chlorodifluoroethane (C2H3C1F2), chlorofluoroethane (C2H4C1F), chloroethane (C2H5C1), dichlorotrifluoroethane (C2HC12F3), dichlorodifluoroethane (C2H2C12F2), dichlorofluoroethane (C2H3C12F), dichloroethane (C2H4C12), trichlorofluoroethane (C2H2C13F), trichlorodifluoroethane (C2HC13F2), trichloroethane (C2H3C13), tetrachlorofluoroethane (C2HC14F), chloroethene (C2H3C1), dichloroethene (C2H2C12), dichlorofluoroethene (C2H2C1F), dichloropentafluoropropane (C3HC12F5) and dichlorodifluoroethene (C2HC1F2).
As used herein the term "fluoroether" means one of the following: trifluoromethyoxy-perfluoromefhane (CF3—O— CF3), difluoromethoxy-perfluoromethane (CHF2—O— CF3), fluoromethoxy-perfluoromethane (CH2F—O—CF3), difluoromethoxy-difluoromethane (CHF2—O—CHF2), difluoromethoxy-perfiuoroethane (CHF2—O—C2F5), difluoromethoxy-l,2,2,2-tetrafiuoroethane (CHF2—O— C2HF4), difluoromethoxy-l,l,2,2-tetra-fluoroethane (CHF2—O—C2HF4), perfluoroethoxyfluoromethane (C2F5—O—CH2F), perfluoromethoxy-l,l,2-trifluoroethane (CF3 — O — C2H2F3), pe rfluoro me thoxy-1,2,2trifluoroethane (CF30—C2H2F3), perfluoroethoxy-methane (C2F5—O—CH3), perfiuoropropoxy-mefhane (C3F7—O— CH3), perfluorobutoxy-methane (C4F9—O—CH3), cyclo-1,
1.2.2- tetrafluoropropylether (cyclo-C3H2F4—O—), cyclo-1,
1.3.3- tetrafluoropropylether (cyclo-C3H2F4—O—), perfluoromethoxy-l,l,2,2-tetrafluoroethane (CF3—O— C2HF4), cyclo-1,1,2,3,3-pentafluoropropylether (cycloC3H5—O—), perfluoromethoxy-perfluoroacetone (CF3— O—CF2—O—CF3), perfluoromethoxy-perfluoroethane (CF3 — O — C2F5), perfluoro me thoxy -1,2,2,2tetrafluoroethane (CF3—O—C2HF4), perfluoromethoxy-2, 2,2-trifluoroethane (CF3—O—C2H2F3), cycloperfiuoromethoxy-perfluoro ace tone (cyclo-CF2—O— CF2—O—CF2—) and cyclo-perfluoropropylether (cycloC3F-0).
As used herein the term "atmospheric gas" means one of the following: nitrogen (N2), argon (Ar), krypton (Kr), xenon (Xe), neon (Ne), carbon dioxide (C02), oxygen (02) and helium (He).
As used herein the term "hydrocarbon" means one of the following: hydrogen (H2), methane (CH4), ethane (C2H6), ethene (C2H4), propane (C3H8), propene (C3H6), butane (C4H10), butene (C4H8), cyclopropane (C3H6) and cyclobutane (C4H8).