US3850004A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryogenic helium refrigeration system
Assignee: Carpenter Technology Corp
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Filing: 1973-06-27
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Granted: 1974-11-26
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Expires: 1993-06-27
Abstract
Abstract Liquid helium vaporized in cooling a refrigeration load is counterflowed through a heat exchanger to cool a high pressure flow of helium which is thereby cooled to below the inversion temperature. The outflow from the warm end of the heat exchanger is compressed to form the high-pressure flow. The cooled highpressure flow of helium is subjected to Joule-Thompson expansion at constant enthalpy to further reduce its temperature and then fed back into the refrigeration load chamber. During cool-down, the system provides a return flow of helium at a temperature below that of the helium withdrawn from the load chamber. When equilibrium is reached, the helium forming the counterflow in the heat exchanger is low enough in temperature so that the cold high-pressure helium output has a less than critical enthalpy so that a major portion of the return flow to the load chamber is liquid helium. Liquid helium is fed into the load chamber from an external source but only at a rate which is a small fraction of the amount of liquid helium required to supercool the load device in normal operation and that amount of helium is removed from the system at the same fractional rate.
Inventors
- 👤 P Arend
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:40
CPC Classifications
F; F25; F25J; F25J1/00; F25J1/02; F25J1/0243; F25J1/0257; F25J1/0275; F25J1/0276; F25B; F25B9/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
178 words
In a cyrogenic helium refrigeration system for cooling a refrigeration load to a predetermined temperature by means of liquid helium at a predetermined pressure, said refrigeration load requiring liquid helium at said pressure at a predetermined flow rate to maintain its normal operating temperature, the steps of feeding liquid helium at said pressure to said refrigeration load from an external supply, feeding helium vaporized by said load through the primary circuit of a heat exchanger as a coolant, compressing the outflow from the primary circuit, then feeding the pressurized helium through the secondary circuit of said heat exchanger and cooling the same below the helium inversion temperature, expanding the cooled highpressure helium isenthalpically to further lower its temperature, then feeding the expanded and cooled helium to said refrigeration load at about said predetermined pressure and at a rate which is less than the rate at which helium is fed from said load to said heat exchanger primary circuit, and removing warm helium from said system at a rate substantially equal to said flow rate from said external supply.
Claim 2
Dependent Claim
178 words
In a cyrogenic helium refrigeration system for cooling a refrigeration load to a predetermined temperature by means of liquid helium at a predetermined pressure, said refrigeration load requiring liquid helium at said pressure at a predetermined flow rate to maintain its normal operating temperature, the steps of feeding liquid helium at said pressure to said refrigeration load from an external supply, feeding helium vaporized by said load through the primary circuit of a heat exchanger as a coolant, compressing the outflow from the primary circuit, then feeding the pressurized helium through the secondary circuit of said heat exchanger and cooling the same below the helium inversion temperature, expanding the cooled highpressure helium isenthalpically to further lower its temperature, then feeding the expanded and cooled helium to said refrigeration load at about said predetermined pressure and at a rate which is less than the rate at which helium is fed from said load to said heat exchanger primary circuit, and removing warm helium from said system at a rate substantially equal to said flow rate from said external supply.
Claim 3
Dependent Claim
46 words
The system as set forth in claim 1 in which the ratio of (a) the flow rate of cooled helium from said heat exchanger to said refrigeration load to (b) the flow rate from said external supply to said refrigeration load is maintained greater than one.
Claim 4
Dependent Claim
17 words
The system as set forth in claim 2 in which said ratio is equal to about 5.
Claim 5
Dependent Claim
39 words
The system as set forth in claim 1 in which the rate of flow of liquid helium from said external supply to said refrigeration load is controlled in response to the level of liquid helium at said refrigeration load.
Claim 6
Dependent Claim
41 words
The system as set forth in claim 4 in which the rate of flow of liquid helium from said external supply is initially controlled in response to the temperature of the warm helium fed from the heat exchanger to be compressed.
Claim 7
Dependent Claim
47 words
The system as set forth in claim 5 in which the rate of flow of liquid helium from said external supply to said refrigeration load is adjusted to maintain the temperature of the warm helium from said heat exchanger at a temperature of about 230* to 270*K.
Claim 8
Dependent Claim
49 words
The system as set forth in claim 1 in which the rate of flow of liquid helium from said external supply to said refrigeration load during cooldown of the latter is controlled in response to the temperature of the warm helium fed from the heat exchanger to be compressed.
Claim 9
Dependent Claim
199 words
A cryogenic helium refrigeration system for cooling a refrigeration load to a predetermined temperature by means of liquid helium from an external supply thereof, said refrigeration load requiring liquid helium at a predetermined pressure and flow rate to maintain its normal operating temperature, comprising means for feeding liquid helium at said pressure to said refrigeration load from said external supply, a heat exchanger having a primary circuit and a secondary circuit, means for feeding helium vaporized by said load through said primary circuit of said heat exchanger as a coolant, means for compressing the helium outflow from said primary circuit, means for feeding the pressurized helium through said secondary circuit of said heat exchanger and cooling the same below the helium inversion temperature, means for expanding the cooled high-pressure helium isenthalpically to further lower its temperature, means for feeding the expandEd and cooled helium to said refrigeration load at about said predetermined pressure and at a rate which is less than the rate at which helium is fed from said load to said heat exchanger primary circuit, and means for removing warm helium from said system at a rate substantially equal to said flow rate from said external supply.
Claim 10
Dependent Claim
199 words
A cryogenic helium refrigeration system for cooling a refrigeration load to a predetermined temperature by means of liquid helium from an external supply thereof, said refrigeration load requiring liquid helium at a predetermined pressure and flow rate to maintain its normal operating temperature, comprising means for feeding liquid helium at said pressure to said refrigeration load from said external supply, a heat exchanger having a primary circuit and a secondary circuit, means for feeding helium vaporized by said load through said primary circuit of said heat exchanger as a coolant, means for compressing the helium outflow from said primary circuit, means for feeding the pressurized helium through said secondary circuit of said heat exchanger and cooling the same below the helium inversion temperature, means for expanding the cooled high-pressure helium isenthalpically to further lower its temperature, means for feeding the expandEd and cooled helium to said refrigeration load at about said predetermined pressure and at a rate which is less than the rate at which helium is fed from said load to said heat exchanger primary circuit, and means for removing warm helium from said system at a rate substantially equal to said flow rate from said external supply.
Claim 11
Dependent Claim
48 words
The system as set forth in claim 8 which further comprises means for maintaining the ratio of (a) the flow rate of cooled helium from said heat exchanger to said refrigeration load to (b) the flow rate from said external supply to said refrigeration load greater than one.
Claim 12
Dependent Claim
17 words
The system as set forth in claim 9 in which said ratio is equal to about 5.
Claim 13
Dependent Claim
40 words
The system as set forth in claim 8 which includes means for controlling the rate of flow of liquid helium from said external supply to said refrigeration load in response to the level of liquid helium at said refrigeration load.
Claim 14
Dependent Claim
39 words
The system as set forth in claim 11 which includes means for initially controlling the rate of flow of liquid helium from said external supply in response to the temperature of the warm helium fed from the heat exchanger.
Claim 15
Dependent Claim
50 words
The system as set forth in claim 12 which includes means for controlling the rate of flow of liquid helium from said external supply to said refrigeration load so as to maintain the temperature of the warm helium from said heat exchanger at a temperature of about 230* to 270*K.
Claim 16
Dependent Claim
47 words
The system as set forth in claim 8 which includes means for controlling the rate of flow of liquid helium from said external supply to said refrigeration load during cooldown of the latter in response to the temperature of the warm helium fed from the heat exchanger.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |