Refrigeration – Cryogenic treatment of gas or gas mixture – Separation of gas mixture
Reexamination Certificate
2000-06-29
2001-12-18
Doerrler, William (Department: 3744)
Refrigeration
Cryogenic treatment of gas or gas mixture
Separation of gas mixture
C062S084000
Reexamination Certificate
active
06330811
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to the provision of refrigeration and, more particularly, to the provision of refrigeration at a cryogenic temperature.
BACKGROUND ART
In a typical refrigeration system, a refrigerant fluid such as R-12, R-134
a
or other freon type refrigerant, is compressed, expanded to generate refrigeration, and then warmed whereby refrigeration is passed from the refrigerant to a refrigeration receiver. The warmed refrigerant is then returned to the compressor and the refrigeration cycle repeats.
The compressor used in the refrigeration cycle is typically oil lubricated and some of this lubricant leaves the compressor with the compressed refrigerant. It is generally good practice to use a lubricating oil, such as a polyolester-based oil, which is highly soluble with the refrigerant. In this way substantially all of the lubricating oil which leaves the compressor with the compressed refrigerant is returned to the compressor with the recycled warmed refrigerant. If a significant amount of the lubricating oil which left the compressor were to remain in the refrigeration circuit and not be returned to the compressor, there may be inadequate lubricating oil in the compressor causing loss of compressor efficiency and perhaps even leading to compressor failure.
Very low temperature or cryogenic refrigeration is becoming increasingly important, such as for use in such fields as energy generation, energy transmission and electronics. Any improvement in refrigeration systems which would enhance the ability to generate and provide refrigeration at a cryogenic temperature would be very desirable.
Accordingly, it is an object of this invention to provide an improved system for generating and providing refrigeration at a cryogenic temperature.
SUMMARY OF THE INVENTION
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 one aspect of which is:
In a method for providing refrigeration wherein a refrigerant fluid is compressed, expanded to generate refrigeration, and then warmed to provide refrigeration to a refrigeration receptor, the improvement comprising:
(A) employing a multicomponent refrigerant as the refrigerant fluid;
(B) compressing the multicomponent refrigerant using a compressor which is lubricated using a polyalphaolefin-based oil; and
(C) providing the refrigeration at a temperature less than 220K.
Another aspect of the invention is:
Apparatus for providing refrigeration comprising:
(A) an oil-lubricated compressor, an oil separation system, means for passing multicomponent refrigerant from the compressor to the oil separation system, and means for passing lubricating oil from the oil separation system to the compressor;
(B) an expansion device, a heat exchanger, means for passing multicomponent refrigerant from the oil separation system to the expansion device, from the expansion device to the heat exchanger, and from the heat exchanger to the compressor; and
(C) means for providing a refrigeration receptor to the heat exchanger whereby refrigeration is provided from the multicomponent refrigerant to the refrigeration receptor.
As used herein the term “indirect heat exchange” means the bringing of two fluids into heat exchange relation without any physical contact or intermixing of the fluids with each other.
As used herein the term “expansion” means to effect a reduction in pressure.
As used herein the term “variable load refrigerant” means a multicomponent refrigerant, i.e. 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 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 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 practice of this invention the temperature differences between the bubble point and the dew point for the multicomponent refrigerant fluid is generally at least 10° C., preferably at least 20° C. and most preferably at least 50° C.
As used herein the term “atmospheric gas” means one of the following: nitrogen (N
2
), argon (Ar), krypton (Kr), xenon (Xe), neon (Ne), carbon dioxide (CO
2
), nitrous oxide (N
2
O), oxygen (O
2
) and helium (He).
As used herein the term “compressor” means a device which increases the pressure of a gas.
As used herein the term “lubricated” means characteristic of a device wherein a substance capable of reducing friction, heat and wear is introduced as a film between solid surfaces of the device.
As used herein the term “polyalphaolefin” means a linear alpha-olefin having six or more carbon atoms.
As used herein the term “polyalphaolefin-based oil” means an oil formulation using one or more polyalphaolefin species in its base stock.
As used herein the term “miscible” means soluble if referring to the interaction of vapor and liquid phases, and means miscible if referring to the interaction of two liquids.
As used herein the term “miscibility” means solubility if referring to the interaction of vapor and liquid phases, and means miscibility if referring to the interaction of two liquids.
REFERENCES:
patent: 5337572 (1994-08-01), Longsworth
patent: 5355695 (1994-10-01), Kawaguchi et al.
patent: 5441658 (1995-08-01), Boyarsky et al.
patent: 5452585 (1995-09-01), Pincus et al.
patent: 5531080 (1996-07-01), Hirahara et al.
patent: 5602086 (1997-02-01), Le et al.
patent: 5706663 (1998-01-01), Boiarski et al.
patent: 5724832 (1998-03-01), Little et al.
patent: 5728655 (1998-03-01), Muraki et al.
patent: 5806336 (1998-09-01), Sunaga et al.
patent: 5866030 (1999-02-01), Reyes-Gavilan et al.
patent: 5953934 (1999-09-01), Makino et al.
patent: 5970722 (1999-10-01), Shibata et al.
patent: 6041620 (2000-03-01), Olszewski et al.
patent: 6041621 (2000-03-01), Olszewski et al.
patent: 6053008 (2000-04-01), Arman et al.
patent: 6176102 (2001-01-01), Novak et al.
Arman Bayram
Bonaquist Dante Patrick
Doerrler William
Drake Malik N.
Ktorides Stanley
Praxair Technology Inc.
LandOfFree
Compression system for cryogenic refrigeration with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compression system for cryogenic refrigeration with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compression system for cryogenic refrigeration with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2565226