US3852566A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fail-safe electric water heater
Assignee: Stackpole Carbon Co
•
Filing: 1973-10-11
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Granted: 1974-12-03
•
Expires: 1993-10-11
Abstract
Abstract Adhering to an electric water heater is a porous layer of heatfused insulating material powder covered by an adhering porous layer of heat-fused electric resistance powder having a negative temperature coefficient of resistivity. The pores of the two layers are filled with dielectric material. Electric terminals connected to the resistance layer are electrically connected with current-actuated circuit breaking means that will be operated by increased current flow through the resistance layer if that layer reaches a predetermined maximum temperature, whereby the water heater is fail safe.
Inventors
- 👤 V Quirk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:45
CPC Classifications
F; F24; F24H; F24H1/00; F24H1/18; F24H1/185; H; H01; H01C; H01C17/00; H01C17/06; H01C17/075; H01C17/10; H01C7/00; H01C7/04; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/141; H05B3/20; H05B3/22; H05B3/26; H05B3/262; H05B2203/00; H05B2203/021
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
97 words
A FAIL-SAFE ELECTRIC WATER HEATER COMPRISING A WATER TANK, A POROUS LAYER OF HEAT-FUSED INSULATING MATERIAL POWDER ON THE TANK AND ADHERINF THERETO A POROUS LAYER OF HEAT-FUSED ELECTRICAL RESISTANCE MATERIAL POWDER COVERING THE INSULATING LAYER AND ADHERING THERETO, SAID RESISTANCE MATERIAL HAVING A NEGATIVE TENPERATURE COEFFICEINT OF RESISTIVITY ELECTRIC TERMINALS CONNECTED TO SAID RESISTANCE LAYER, DIELECTRIC MATERIAL FILLING THE PORES OF SAID POROUS LAYERS, AND MEANS FOR ELECTRICALLY CONNECTING THE TERMINALS WITH CURRENT-ACTUATED CIRCUIT BREAKING MEANS THAT WILL BE OPERATED BY INCREASED CURRENT FLOW THROUGH THE RESISTANCE LAYER IF THAT LAYER REACHES A PREDETERMINED MAXIMUM TEMPERATURE.
Claim 2
Dependent Claim
97 words
A FAIL-SAFE ELECTRIC WATER HEATER COMPRISING A WATER TANK, A POROUS LAYER OF HEAT-FUSED INSULATING MATERIAL POWDER ON THE TANK AND ADHERINF THERETO A POROUS LAYER OF HEAT-FUSED ELECTRICAL RESISTANCE MATERIAL POWDER COVERING THE INSULATING LAYER AND ADHERING THERETO, SAID RESISTANCE MATERIAL HAVING A NEGATIVE TENPERATURE COEFFICEINT OF RESISTIVITY ELECTRIC TERMINALS CONNECTED TO SAID RESISTANCE LAYER, DIELECTRIC MATERIAL FILLING THE PORES OF SAID POROUS LAYERS, AND MEANS FOR ELECTRICALLY CONNECTING THE TERMINALS WITH CURRENT-ACTUATED CIRCUIT BREAKING MEANS THAT WILL BE OPERATED BY INCREASED CURRENT FLOW THROUGH THE RESISTANCE LAYER IF THAT LAYER REACHES A PREDETERMINED MAXIMUM TEMPERATURE.
Claim 3
Dependent Claim
26 words
A fail-safe water heater according to claim 1, in which said resistance layer is formed from ceramic ferrite powder fused together and to said insulating layer.
Claim 4
Dependent Claim
24 words
A fail-safe water heater according to claim 1, in which said terminals are formed from metal particles fused together and to said resistance layer.
Claim 5
Dependent Claim
34 words
A fail-safe water heater according to claim 3, in which said layers and terminals encircle the tank, and said connecting means include metal clamping bands encircling the tank in tight engagement with said terminals.
Claim 6
Dependent Claim
20 words
A fail-safe electric water heater according to claim 1, in which said electric terminals are spaced lengthwise of the tank.
Claim 7
Dependent Claim
27 words
A fail-safe electric water heater according to claim 1, in which said layers and terminals encircle the tank, and the terminals are spaced lengthwise of the tank.
References Cited (Backward Citations)
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US3108170A
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Cited
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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) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |