US3581512A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid helium refrigeration apparatus and method
Assignee: US Philips Corp
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Filing: 1969-06-02
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Granted: 1971-06-01
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Expires: 1989-06-02
Abstract
Abstract A refrigerator operating below the lambda -point of 4He in which a mixture of 3He and 4He is circulated by means of a liquid pump first to a cooler having a temperature lower than that of the lambda -point of the mixture producing superfluid 4He in addition to a mixture of normal 4He and liquid 3He. The superfluid 4He is passed through a superleak and combined with said mixture to dilute same in a mixing chamber, thus producing cold to cool an object disposable in the chamber. An exhaust duct from the mixing chamber is proportioned so that the medium discharged therethrough exceeds its critical speed and thus flows turbulently.
Inventors
- 👤 Frans Adrianus Staas
- 👤 Adrianus Petrus Severijns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:59
CPC Classifications
F; F25; F25B; F25B9/00; F25B9/12
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
14 words
A device according to claim 1 wherein the liquid pump is a centrifugal pump.
Claim 2
Dependent Claim
52 words
A device according to claim 1, further comprising a reservoir containing liquid helium at a temperature which is lower than that of the lambda -point of 4He the mixing chamber, the first and second supply duct and the exhaust duct being arranged in a vacuUm-insulated space which is immersed in said reservoir.
Claim 3
Dependent Claim
54 words
A device according to claim 1, further comprising an additional device for transporting thermal energy from a lower to a higher temperature level, which two levels also lie below the temperature of the lambda -point of 4He, and the coldest part of which device is in heat exchanging relationship with the first supply duct.
Claim 4
Dependent Claim
164 words
Apparatus operating with a supply mixture of liquid helium for producing cold or cool an object, comprising: a. pump means for applying a pressure to flow the supply mixture of liquid helium, b. cooler means for cooling the flowing helium to a temperature below its lambda -point, with a resulting mixture of superfluid 4He, normal 4He, and liquid 3He components, c. a superleak through which flows only superfluid 4He from the cooler, d. a supply duct through which flows liquid 4He and liquid 3He from said cooler, e. a mixing chamber in which an object to be cooled is disposable, and into which flows said mixture of liquid 3He and liquid 4He from the supply duct which mixture is diluted in the chamber by superfluid 4He which flows into the chamber from the superleak, with a production of cold resulting in the chamber for cooling the object therein, and f. exhaust duct means for discharge of the diluted fluid mixture from the mixing chamber.
Claim 5
Dependent Claim
31 words
Apparatus according to claim 5 wherein said exhaust duct has an outlet to said pump means, and said exhaust duct is dimensioned internally such that fluid flow therethrough will be turbulent.
Claim 6
Dependent Claim
22 words
Apparatus according to claim 5 further comprising a chamber containing a cooling bath of liquid 4He maintained below the lambda -point thereof.
Claim 7
Dependent Claim
22 words
Apparatus according to claim 5 further comprising a vacuum-insulated housing containing said mixing chamber, the superleak, the supply duct and exhaust duct.
Claim 8
Dependent Claim
31 words
Apparatus according to claim 5 wherein the fluid in the supply duct is a mixture of liquid 3He and 4He at a temperature below the lambda -point of said 3He-4He mixture.
Claim 9
Dependent Claim
33 words
Apparatus according to claim 8 further comprising a reservoir for containing liquid 4He at a temperature below the lambda -point thereof in said vacuum-insulated housing immersed in the liquid 4He of said reservoir.
Claim 10
Independent Claim
110 words
A method for cooling an object, comprising the steps: a. cooling a mixture of liquid 3He and 4He to below the lambda -point, thus forming a quantity of superfluid 4He within the mixture, b. separating at least some of the superfluid 4He from the 3He-4He mixture by flowing(i) the superfluid 4He through a superleak, and (ii) the remaining 3He-4He mixture through a supply duct, c. flowing both (i) the 3He-4He mixture and (ii) the superfluid 4He into a mixing chamber, thereby diluting the 3He-4He mixture with the superfluid 4He, and producing cold in said chamber for cooling an object therein, and d. flowing the diluted mixture out of the chamber.
Claim 11
Dependent Claim
21 words
A method according to claim 11 wherein flowing said liquid helium 4He and 3He comprises pumping same with a pump means.
Claim 12
Dependent Claim
23 words
A method according to claim 11 wherein flowing the diluted mixture of liquid helium out of the mixing chamber comprises flowing same turbulently.
Claim 13
Dependent Claim
60 words
A method according to claim 11 further comprising insulating from heat transfer by using a vacuum chamber, said steps of (i) separating and flowing the superfluid 4He through a superleak, (ii) flowing the remaining mixture through a supply duct, (iii) mixing said flows from the superleak and the supply duct, and (iv) discharging the mixed helium from the mixing chamber.
Claim 14
Dependent Claim
25 words
A method according to claim 11 further comprising maintaining a quAntity of liquid 4He about said vacuum chamber at below the lambda -point temperature thereof.
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) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |