US3774404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adiabatic magnetization cooling near absolute zero
Assignee: AT&T Inc
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Filing: 1971-03-19
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Granted: 1973-11-27
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Expires: 1991-03-19
Abstract
Abstract Cryogenic temperatures within one millidegree of absolute zero are attained by a combined application of pressure and magnetic field to He3 which has been precooled to below 15 millidegrees. The pressures required are above 33.8 atmospheres and the magnetic fields are between 30 kilogauss and 80 kilogauss.
Inventors
- 👤 L Walker
- 👤 R Walstedt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:32
CPC Classifications
F; F25; F25B; F25B21/00; F25B2321/00; F25B2321/002; F25B2321/0021; Y; Y02; Y02B; Y02B30/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
68 words
A cooling method comprising compressing a refrigerant consisting essentially of a mixture of solid and liquid He3 to a pressure greater than 29 atmospheres characterized in that the method comprises imposing upon the refrigerant a magnetic field of magnitude between 30 X 103 gauss and 80 X 103 gauss whereby the temperature of the refrigerant is reduced below that temperature produced in the absence of the magnetic field.
Claim 2
Dependent Claim
68 words
A cooling method comprising compressing a refrigerant consisting essentially of a mixture of solid and liquid He3 to a pressure greater than 29 atmospheres characterized in that the method comprises imposing upon the refrigerant a magnetic field of magnitude between 30 X 103 gauss and 80 X 103 gauss whereby the temperature of the refrigerant is reduced below that temperature produced in the absence of the magnetic field.
Claim 3
Dependent Claim
22 words
A method of claim 1 in which the compression of the refrigerant takes place prior to the imposition of the magnetic field.
Claim 4
Dependent Claim
14 words
A method of claim 2 in which the pressure is greater than 33.8 atmospheres.
Claim 5
Dependent Claim
25 words
A method of claim 1 in which the magnitude of the magnetic field is between +1 percent and -3 percent of 74 X 103 gauss.
Claim 6
Dependent Claim
37 words
A method of claim 1 comprising bringing the refrigerant to an initial temperature less than 15 X 10 3 K in which the compression of the refrigerant takes place subsequent to the imposition of the magnetic field.
Claim 7
Dependent Claim
22 words
A method of claim 1 comprising bringing the refrigerant into thermal contact with a body thus reducing the temperature of the body.
References Cited (Backward Citations)
US3125861A
Cited
US2913881A
Cited
US3004394A
Cited
US3119236A
Cited
US3108444A
Cited
US3393526A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |