US3684923A
Expired / Lapsed
US
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Cryogenic fuse
Assignee: Individual
•
Filing: 1971-08-18
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Granted: 1972-08-15
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Expires: 1991-08-18
Abstract
Abstract A fuse element is manufactured of lead or other suitable material displaying superconductive properties at very low temperatures. A fuse including such an element is employed in a high voltage transmission line by serially inserting the fuse element in the line and maintaining the element in its superconductive state by using a liquified gas to cool the element during normal current levels. A sensor is provided which develops a control signal in the event excessive current levels are reached. The control signal is applied to control means which automatically vents the fuse by allowing the coolant to escape and thereby raises the temperature of the fuse such that its normal resistivity returns. The resulting I2R heat developed within the element due to the current flow therein will cause the element to immediately vaporize thereby opening the circuit. In other embodiments the control signal can be employed to provide power to a heating element mounted in thermal proximity with the fuse element to increase its temperature in the event of excessive current. Also the control signal can be employed to cause a magnetic field to be developed which causes the fuse to return to its normal resistivity. The fuse and its related circuitry can be designed to provide either a fast-blow or a slow-blow operating fuse.
Inventors
- 👤 Miner S Keeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:52
CPC Classifications
H; H01; H01H; H01H85/00; H01H85/02; H01H85/47; H02; H02H; H02H3/00; H02H3/02; H02H3/021; H02H3/08; H10; H10N; H10N60/00; H10N60/30; H10N60/35; H10N60/355; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/85
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
92 words
A cryogenic fuse comprising: a fuse element comprising a material displaying superconductive properties at low temperatures, and relatively high resistive properties at temperatures above the superconductive temperature region; a source of cryogenic liquid; means for supplying said cryogenic liquid in thermal communication with said fuse element thereby holding said fuse element in its superconductive state; and means for returning said fuse element to the normal resistivity state in response to predetermined current levels such that said fuse element will vaporize due to heat produced in said fuse element by current flowing therethrough.
Claim 2
Dependent Claim
92 words
A cryogenic fuse comprising: a fuse element comprising a material displaying superconductive properties at low temperatures, and relatively high resistive properties at temperatures above the superconductive temperature region; a source of cryogenic liquid; means for supplying said cryogenic liquid in thermal communication with said fuse element thereby holding said fuse element in its superconductive state; and means for returning said fuse element to the normal resistivity state in response to predetermined current levels such that said fuse element will vaporize due to heat produced in said fuse element by current flowing therethrough.
Claim 3
Dependent Claim
33 words
A fuse as defined in claim 1 wherein said returning means comprises means for venting said cryogenic liquid thereby allowing the temperature of said fuse element to rise above the superconductive temperature region.
Claim 4
Dependent Claim
33 words
A fuse as defined in claim 1 wherein said returning means comprises means for applying a magnetic field to said fuse element such that said element will return to the normal resistivity state.
Claim 5
Dependent Claim
81 words
A fuse as defined in claim 1 wherein said returning means comprises means for increasing the temperature of said fuse element comprising sensing means for detecting the level of current in said fuse element and for providing signals representative thereof, control means coupled to said sensing means and responsive to signals therefrom such that when excessive current levels in said fuse element are detected, said control means operates to raise the temperature of said fuse element above its superconductive temperature region.
Claim 6
Dependent Claim
51 words
A fuse as defined in claim 4 wherein said control means includes a power source selectively operated to apply power to a heating element placed in thermal proximity with said fuse element such that when said power supply is activated, said heating element will raise the temperature of said fuse element.
Claim 7
Dependent Claim
21 words
A fuse as defined in claim 5 wherein said fuse element comprises lead and wherein said cryogenic liquid comprises liquified helium.
Claim 8
Dependent Claim
80 words
A fuse as defined in claim 4 wherein said control means comprises an insulating sleeve enclosing said fuse element and cryogenic liquid, said sleeve comprising first and second portions hingedly mounted one to another at a first seam therebetween, and bonded to one another by securing means at a second seam thereof, said securing means being responsive to said signals indicating an excessive current level to explosively open said insulating shell thereby venting said fuse element to raise its temperature.
Claim 9
Dependent Claim
21 words
A fuse as defined in claim 7 wherein said fuse element comprises lead and wherein said cryogenic liquid comprises liquified helium.
Claim 10
Dependent Claim
31 words
A fuse as defined in claim 4 and including further means for selectively causing said fuse element to vaporize only after a predetermined current overload is detected by said sensing means.
Claim 11
Dependent Claim
41 words
A fuse as defined in claim 9 wherein said further means includes circuit means for providing a signal to said control means which indicate an excessive current only after a predetermined number of current overload pulses of predetermined duration have occurred.
Claim 12
Dependent Claim
103 words
A fuse as defined in claim 10 wherein said circuit means includes: a pulse generator, a gated counter coupled to said pulse generator and operative to count pulses from said generator only in the presence of a signal from said sensing means which indicates the presence of current overload pulses, said signal from said sensing means being applied to the control element on said gated counter, anD comparator means coupled to said gated counter and to said control means for providing a signal to said control means when a predetermined number of said pulses from said pulse generator have accumulated in said counter.
Claim 13
Dependent Claim
17 words
A fuse as defined in claim 11 and further including means for periodically resetting said gated counter.
Claim 14
Dependent Claim
117 words
A fuse comprising a fuse element made of material displaying superconductive electrical properties below a predetermined temperature, said fuse element installed in series with an electrical conductor; means for maintaining said fuse element below said predetermined temperature when electrical current of a normal level flows through said conductor; sensing means for detecting an excessive current level in said conductor and for producing a control signal in response thereto; and control means coupled to said sensing means and responsive to said control signal therefrom to raise the temperature of said fuse element above said predetermined temperature such that said fuse element becomes relatively resistive and vaporizes due to heat generated therein caused by the flow of current therethrough.
Claim 15
Dependent Claim
117 words
A fuse comprising a fuse element made of material displaying superconductive electrical properties below a predetermined temperature, said fuse element installed in series with an electrical conductor; means for maintaining said fuse element below said predetermined temperature when electrical current of a normal level flows through said conductor; sensing means for detecting an excessive current level in said conductor and for producing a control signal in response thereto; and control means coupled to said sensing means and responsive to said control signal therefrom to raise the temperature of said fuse element above said predetermined temperature such that said fuse element becomes relatively resistive and vaporizes due to heat generated therein caused by the flow of current therethrough.
Claim 16
Dependent Claim
43 words
A fuse as defined in claim 13 wherein said maintaining means comprises: a source of cryogenic liquid, means for supplying liquid from said cryogenic source in thermal proximity with said fuse element, and insulating means surrounding said fuse element and said cryogenic liquid.
Claim 17
Dependent Claim
45 words
A fuse as defined in claim 13 wherein said control means comprises means for explosively removing said insulating means such that said cryogenic liquid will be vented thereby raising the temperature of said fuse element such that said material will return to its normal resistivity.
Claim 18
Dependent Claim
19 words
A fuse as defined in claim 15 wherein said material comprises lead and said cryogenic liquid comprises liquified helium.
Claim 19
Dependent Claim
32 words
A fuse as defined in claim 13 wherein said control means includes a power supply selectively operated to apply power to a heating element mounted in thermal contact with said fuse element.
Claim 20
Dependent Claim
43 words
A fuse as defined in claim 17 and further including sensing means for detecting excessive current in said fuse element and for providing a control signal in response thereto to selectively operate said power supply and thereby provide power to said heating element.
Claim 21
Dependent Claim
90 words
A fuse as defined in claim 5 wherein said insulator comprises a sleeve formed of first and second portions joined at a first seam thereof by hinge means, and said means for explosively removing said insulating means comprises securing means joining said first and second sleeve portions at a second seam, said securing means coupled to said sensing means and responsive to said control signals developed by said sensing means during current overloads to explosively separate said first and second sleeve portions in the event a current overload is detected.
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) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |