US3698200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryogenic storage dewar
Assignee: Air Products and Chemicals Inc
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Filing: 1970-12-16
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Granted: 1972-10-17
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Expires: 1990-12-16
Abstract
Abstract A non-continuous venting dewar for safely storing a cryogenic fluid during a prolonged period of transit with minimized evaporation of the cryogenic fluid. The dewar is characterized in that between the inner storage tank of the traditional vacuumjacketed cryogenic storage dewar and the outer shell thereof, there is placed a plurality of spaced-apart radiation shields, the innermost of which is of relatively greater mass than the others and can be reduced in temperature to approximately the level of the stored cryogenic fluid as the dewar is filled.
Inventors
- 👤 Glenn B Johnson
- 👤 John L Petering
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 01:56
CPC Classifications
F; F17; F17C; F17C3/00; F17C3/02; F17C3/08; F17C2203/00; F17C2203/01; F17C2203/014; Y; Y10; Y10S; Y10S220/00; Y10S220/901
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
182 words
A dewar for transporting cryogenic fluid with minimum loss by evaporation of the fluid comprising in combination: an inner tank for receiving and holding the cryogenic fluid; an outer shell spaced apart from and surrounding said inner tank in vacuum tight relationship thereto; low conductivity means for supporting said inner tank in spaced relationship from said outer shell; means for preventing heat influx into said inner tank, said means comprising a massive self-supporting radiation shield spaced apart from and surrounding said inner vessel with venting means disposed around a major portion of the surface of said shield, said venting means for venting said inner vessel outwardly of the dewar so that said radiation shield can be precooled during filling of the inner vessel to about 4* K, thereby acting as a large heatsink to prevent heat influx into the inner vessel; a second radiation shield spaced apart from and between said first shield and said shell; means for filling said inner vessel; and means for holding a second volume of cryogenic fluid against a portion of the surface of said second shield.
Claim 2
Dependent Claim
182 words
A dewar for transporting cryogenic fluid with minimum loss by evaporation of the fluid comprising in combination: an inner tank for receiving and holding the cryogenic fluid; an outer shell spaced apart from and surrounding said inner tank in vacuum tight relationship thereto; low conductivity means for supporting said inner tank in spaced relationship from said outer shell; means for preventing heat influx into said inner tank, said means comprising a massive self-supporting radiation shield spaced apart from and surrounding said inner vessel with venting means disposed around a major portion of the surface of said shield, said venting means for venting said inner vessel outwardly of the dewar so that said radiation shield can be precooled during filling of the inner vessel to about 4* K, thereby acting as a large heatsink to prevent heat influx into the inner vessel; a second radiation shield spaced apart from and between said first shield and said shell; means for filling said inner vessel; and means for holding a second volume of cryogenic fluid against a portion of the surface of said second shield.
Claim 3
Dependent Claim
36 words
A vessel according to claim 1 wherein the second volume of cryogenic fluid is held in a vessel defined by a portion of the surface of the second shield and a spaced apart complimentary structural member.
Claim 4
Dependent Claim
49 words
A vessel according to claim 1 wherein the inner vessel is supported by a system including hollow elongate trunions of low conductivity material between said inner vessel and said low conductivity support means on the inner surface of said outer shell to minimize heat conduction to said inner vessel.
Claim 5
Dependent Claim
27 words
A vessel according to claim 1 wherein said inner vessel surfaces and said radiation shield surfaces exposed to the vacuum are coated with a low emissivity coating.
Claim 6
Dependent Claim
23 words
A vessel according to claim 1 wherein between said outer shell and said second radiation shield there is disposed a multi-layer super insulation.
Claim 7
Independent Claim
147 words
A method for transporting a cryogenic fluid over long distances in a storage dewar having an inner vessel including a filling conduit, to hold the cryogenic fluid, spaced apart and in vacuum tight relation with the inner vessel an outer shell with at least one radiation shield of significant mass to act as a heatsink when precooled to approximately 4* K and having an inner vessel vent conduit in intimate contact with a major portion of said shield comprising the steps of: introducing into the inner vessel the cryogenic fluid to be transported; allowing a portion of the cryogenic fluid to escape from the vent during filling of the vessel to precool the radiation shield and establish the heatsink; filling the inner vessel to capacity; sealing the inner vessel, filling and venting conduits to prevent further escape of the cryogenic fluid; and TRANSPORTING the dewar to destination.
Claim 8
Independent Claim
147 words
A method for transporting a cryogenic fluid over long distances in a storage dewar having an inner vessel including a filling conduit, to hold the cryogenic fluid, spaced apart and in vacuum tight relation with the inner vessel an outer shell with at least one radiation shield of significant mass to act as a heatsink when precooled to approximately 4* K and having an inner vessel vent conduit in intimate contact with a major portion of said shield comprising the steps of: introducing into the inner vessel the cryogenic fluid to be transported; allowing a portion of the cryogenic fluid to escape from the vent during filling of the vessel to precool the radiation shield and establish the heatsink; filling the inner vessel to capacity; sealing the inner vessel, filling and venting conduits to prevent further escape of the cryogenic fluid; and TRANSPORTING the dewar to destination.
Claim 9
Dependent Claim
20 words
A method according to claim 6 wherein the first cryogenic fluid is helium and the second cryogenic fluid is nitrogen.
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) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |