US3816704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface heating apparatus
Assignee: General Electric Co
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Filing: 1972-03-20
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Granted: 1974-06-11
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Expires: 1992-03-20
Abstract
Abstract A smooth surface heating apparatus is provided having a heat spreader plate of high thermal conductivity coated, at least on its upper surface, with a glass-ceramic material containing a predominant crystalline phase of lithium disilicate in a glassy matrix and having a coefficient of expansion in the range of 80120 X 10 7 per *C. An insulated electrical resistance heating element and a reinforcing member are attached to the underside of the heat spreader plate. A reflector pan is provided beneath the heating element to direct the heat in an upward direction.
Inventors
- 👤 M Borom
- 👤 J Burke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:47
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/68; H05B3/74; H05B3/748; C; C03; C03C; C03C10/00; C03C10/0009; C03C10/0018; C03C10/0027; C03C10/0036; C03C10/0054; C03C3/00; C03C3/04; C03C3/076; C03C3/097; C03C4/00; F; F24; F24C; F24C15/00; F24C15/10; H05B3/688; C03C2204/00; C03C2204/04; Y; Y10; Y10S; Y10S252/00; Y10S252/962
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
102 words
A surface heating apparatus comprising a metallic heat spreader plate of high thermal conductivity, an insulated electrical resistance heating element attached to the underside of said plate for heating thereof, and a glass-ceramic coating covering at least the upper surface of the plate, said glassceramic consisting essentially as calculated from the batch on the oxide basis in weight percent of 6-20% Li2O, 0-10% Al2O3, 7080% SiO2, 0.5-6.0% P2O5, 0-10% B2O3, 0-6% K2O and 0-5% ZnO, wherein the coefficient of expansion of the glass-ceramic is in the range of 80-120 X 10 7 per *C. and the major crystalline phase is lithium disilicate.
Claim 2
Dependent Claim
102 words
A surface heating apparatus comprising a metallic heat spreader plate of high thermal conductivity, an insulated electrical resistance heating element attached to the underside of said plate for heating thereof, and a glass-ceramic coating covering at least the upper surface of the plate, said glassceramic consisting essentially as calculated from the batch on the oxide basis in weight percent of 6-20% Li2O, 0-10% Al2O3, 7080% SiO2, 0.5-6.0% P2O5, 0-10% B2O3, 0-6% K2O and 0-5% ZnO, wherein the coefficient of expansion of the glass-ceramic is in the range of 80-120 X 10 7 per *C. and the major crystalline phase is lithium disilicate.
Claim 3
Dependent Claim
37 words
The heating apparatus of claim 1, comprising additionally a reinforcing member attached to the underside of said plate to prevent warpage and a reflector pan beneath the heating element to direct the heat in an upward direction.
Claim 4
Dependent Claim
19 words
The heating apparatus of claim 1, wherein said glass-ceramic coating has a thickness of about 3 to 12 mils.
Claim 5
Dependent Claim
21 words
The heating apparatus of claim 2, wherein said coating covers both sides of the heat spreader plate and the heating element.
Claim 6
Dependent Claim
19 words
The heating apparatus of claim 1, wherein the glass-ceramic coating contains up to about 50% of a crystalline phase.
Claim 7
Dependent Claim
22 words
The heating apparatus of claim 1, wherein said glass-ceramic coating additionally contains up to 5% by weight of a conventional coloring agent.
Claim 8
Dependent Claim
37 words
The heating apparatus of claim 1, wherein said glass-ceramic coating consists essentially as calculated from the batch on the oxide basis in weight percent of about 73.0% SiO2, 13.7% Li2O, 5.6% K2O, 4.9% Al2O3 and 2.8% P2O5.
Claim 9
Dependent Claim
54 words
The heating apparatus of claim 1, wherein said heat spreader plate is a composite metal sheet material having a core selected from the group consisting of copper, silver and aluminum placed between two integral outer layers of a metal or alloy selected from the group consisting of carbon steel, stainless steel, nickel and chromium.
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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) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |