Claims
- 1. In a multi-stage cold accumulation type refrigerator comprising a compressor disposed at an ordinary temperature, a helium gas as a common operating fluid to be compressed by said compressor, and one or more expansion chambers and clod accumulators of different temperature levels; the improvements wherein at least one of said expansion chambers has a seal to prevent leakage of said helium gas, said seal being capable of sliding, wherein sliding resistance of said seal generates less heat than the theoretical generated refrigeration quantity of said expansion chamber, said theoretical generated refrigeration quantity being based on isothermal expansion in said expansion chamber; and a cold accumulating member of said cold accumulators is formed of an alloy or compound containing a rare earth metal.
- 2. The multi-stage cold accumulation type refrigerator of claim 1, wherein said multi-stage cold accumulation type refrigerator further comprises one or more cylinders, a thermal anchor mounted on an outer surface of said cylinder at a position corresponding to the location where said seal slides, said thermal anchor being formed of a good heat conductor and being thermally connected to a high-temperature thermal stage so as to absorb heat generation due to sliding resistance of said seal.
- 3. The multi-stage cold accumulation type refrigerator of claim 2, wherein said magnet is provided at the outlet of said cold accumulator, for trapping a fine powder expelled from said cold accumulating member.
- 4. The multi-stage cold accumulation type refrigerator of claim 2, wherein said magnet is in the center of said cold accumulator, to suppress a fine powder of said cold accumulating members from being expelled.
- 5. The multi-stage cold accumulation type refrigerator as defined in claim 1, further comprising a magnet for trapping a fine powder of said cold accumulating member.
- 6. The multi-stage cold accumulation type refrigerator of claim 5, wherein said multi-stage cold accumulation type refrigerator further comprises a container for containing helium mounted to an end of one of said cylinders of said cold accumulators, or is disposed below said second cold accumulating member, so as to reduce a temperature change in a refrigeration cycle.
- 7. The multi-stage cold accumulation type refrigerator of claim 1, wherein said seal comprises a piston ring and a tension ring.
- 8. The multi-stage cold accumulation type refrigerator of claim 1, wherein said seal is a labyrinth seal.
- 9. The multi-stage cold accumulation type refrigerator of claim 1, wherein said expansion chamber has an inner wall and an outer wall, and said seal slides between said inner wall and said outer wall.
- 10. The multi-stage cold accumulation type refrigerator of claim 9, wherein said inner wall has a surface roughness of about 3 .mu.m RMS or less.
- 11. The multi-stage cold accumulation type refrigerator of claim 1, wherein said heat generated by said sliding resistance of said seal is 4% of said theoretical generated refrigeration quantity of said expansion chamber.
- 12. The multi-stage cold accumulation type refrigerator of claim 1, wherein one of said cold accumulators comprises a first cold accumulating member at a high temperature level formed from GdRh and a second cold accumulating member at a low temperature level formed from Gd.sub.0.5 Er.sub.0.5 Rh, said GdRh being present in a weight percentage of 45-65%, based on the total amount of GdRh and Gd.sub.0.5 Er.sub.0.5 Rh.
Priority Claims (6)
Number |
Date |
Country |
Kind |
2-84450 |
Nov 1988 |
JPX |
|
63-84452 |
Nov 1988 |
JPX |
|
63-84453 |
Nov 1988 |
JPX |
|
63-84454 |
Nov 1988 |
JPX |
|
63-84455 |
Nov 1988 |
JPX |
|
63-85991 |
Nov 1988 |
JPX |
|
Parent Case Info
The present invention is a divisional of Ser. No. 07/722,547, filed Jun. 26, 1991, now U.S. Pat. No. 5,154,063, Ser. No. 07/721,816, filed Jun. 26, 1991, now U.S. Pat. No. 5,144,805, and Ser. No. 07/721,135, filed Jun. 26, 1991, now U.S. Pat. No. 5,144,810, each of which is, in turn, a divisional of Ser. No. 07/430,582, filed Nov. 1, 1989, issued Mar. 3, 1992 as U.S. Pat. No. 5,092,130.
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Jun 1982 |
EPX |
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FRX |
1-23852 |
Mar 1989 |
JPX |
1-36029 |
Jul 1989 |
JPX |
Non-Patent Literature Citations (8)
Entry |
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Related Publications (2)
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Number |
Date |
Country |
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721861 |
Jun 1991 |
|
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721135 |
Jun 1991 |
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Divisions (2)
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Number |
Date |
Country |
Parent |
722547 |
Jun 1991 |
|
Parent |
430582 |
Nov 1989 |
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