US3719796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heating unit having a ptc heating resistor
Assignee: Danfoss AS
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Filing: 1971-07-21
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Granted: 1973-03-06
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Expires: 1991-07-21
Abstract
Abstract The invention relates to an electrical heating unit for appliance such as coffee makers, hot plates and the like. The heating unit includes a PTC resistor which is mounted so as to be completely surrounded by a liquid medium so that a uniform temperature is maintained for the external surface of the resistor. This uniform temperature prevents cracking of the resistor due to unevenly distributed thermal strains.
Inventors
- 👤 J Abildtrup
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:58
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/022; G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/2401
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
106 words
A heating unit comprising a sealed metal case for a liquid, said case having top, sides and bottom walls, a PTC heating resistor mounted in said case in spaced relation to said walls, a heat conductive liquid in said case in substantially complete surrounding relation to said resistor, said top wall being in contact with a heat conductive state for conducting heat thereto, electrical leads for said resistor extending through one of said walls and electrically insulated therefrom, said one of walls having an opening, and a resilient sheet portion closing said opening and being outwardly expandable in response to the liquid inner pressure applied thereto.
Claim 2
Dependent Claim
106 words
A heating unit comprising a sealed metal case for a liquid, said case having top, sides and bottom walls, a PTC heating resistor mounted in said case in spaced relation to said walls, a heat conductive liquid in said case in substantially complete surrounding relation to said resistor, said top wall being in contact with a heat conductive state for conducting heat thereto, electrical leads for said resistor extending through one of said walls and electrically insulated therefrom, said one of walls having an opening, and a resilient sheet portion closing said opening and being outwardly expandable in response to the liquid inner pressure applied thereto.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |