US3854524A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermal switch-heat pipe
Assignee: United States Atomic Energy Commission
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Filing: 1972-09-07
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Granted: 1974-12-17
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Expires: 1992-09-07
Abstract
Abstract A radial heat pipe is fitted with a wick and working fluid for the temperature of interest and operated in such a manner as to act as a thermal switch. The heat pipe surrounds nuclear fuel elements and during normal temperature operation transports negligible energy but upon a surge in fuel element temperature large amounts of heat can be transported to limit the fuel element temperature.
Inventors
- 👤 K Gregorie
- 👤 H Pfefferlen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 01:26
CPC Classifications
F; F28; F28D; F28D15/00; F28D15/02; F28D15/04; F28D15/046; G; G21; G21C; G21C1/00; G21C1/30; G21C1/303; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
247 words
An apparatus defining a thermal switch positioned about a nuclear heat source capable of producing a large change in thermal conductivity of a structure by a relatively small change in the temperature of the hotter side of the structure such that negligible heat is transported during a predetermined operating temperature of the structure while a large amount of heat is transported during a temperature excursion comprising: vertically positioned annular evaporator means defining a first wall member, annular condenser means positioned externally of and in vertical spaced relationship with respect to said evaporator means and defining a second wall member, means defining a third member interconnecting one end of said wall member of said evaporator means and one end of said wall member of said condenser means defining an annular chamber therebetween and forming an annular reservoir for working fluid at the lower end portion thereof, wick means located within said chamber and said reservoir and secured only to said wall member of said evaporator means, said wick means being selected from the group consisting of a plurality of layers of fine mesh screen and a layer of powdered stainless steel bonded to said wall member of said evaporator means, and a quantity of working fluid retained in said reservoir and in contact with a portion of said wick means, said working fluid being selected from the group consisting of lithium and sodium and of the type capable of climbing by capillary action and wetting said wick means.
Claim 2
Independent Claim
247 words
An apparatus defining a thermal switch positioned about a nuclear heat source capable of producing a large change in thermal conductivity of a structure by a relatively small change in the temperature of the hotter side of the structure such that negligible heat is transported during a predetermined operating temperature of the structure while a large amount of heat is transported during a temperature excursion comprising: vertically positioned annular evaporator means defining a first wall member, annular condenser means positioned externally of and in vertical spaced relationship with respect to said evaporator means and defining a second wall member, means defining a third member interconnecting one end of said wall member of said evaporator means and one end of said wall member of said condenser means defining an annular chamber therebetween and forming an annular reservoir for working fluid at the lower end portion thereof, wick means located within said chamber and said reservoir and secured only to said wall member of said evaporator means, said wick means being selected from the group consisting of a plurality of layers of fine mesh screen and a layer of powdered stainless steel bonded to said wall member of said evaporator means, and a quantity of working fluid retained in said reservoir and in contact with a portion of said wick means, said working fluid being selected from the group consisting of lithium and sodium and of the type capable of climbing by capillary action and wetting said wick means.
Claim 3
Dependent Claim
38 words
The apparatus defined in claim 1, wherein said heat source comprises at least one nuclear fuel pin, said evaporator means of said apparatus being positioned in spaced relationship with said fuel pin defining a coolant flow path therebetween.
Claim 4
Dependent Claim
29 words
The combination defined in claim 2, wherein said apparatus surrounds at least one nuclear fuel pin such that said evaporator means defines an annulus therebetween for coolant flow therethrough.
Claim 5
Dependent Claim
32 words
The apparatus defined in claim 1, wherein said heat source comprises a plurality of nuclear fuel pins wherein said first wall member surrounds said fuel pins defining a coolant flow path therebetween.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |