Patent US4654510A successfully refreshed from Google Patents.
US4654510A
Expired / Lapsed
US
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PTC heating apparatus
Assignee: TDK Corp
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Filing: 1979-10-17
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Granted: 1987-03-31
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Expires: 1999-10-17
Abstract
Abstract A PTC heating element with a honeycomb ceramic body comprising a barium titanate and semiconductor element, which provides the ceramic body with a positive temperature coefficient of resistance over the Curie point. An electrode is deposited on each end of the honeycomb body. The electrodes according to the present invention have a non-ohmic property, while the conventional electrodes have been ohmic. A high rush current and migration are advantageously decreased by the non-ohmic electrodes.
Inventors
- 👤 Kazumasa Umeya
- 👤 Ryoichi Shioi
- 👤 Hisao Senzaki
- 👤 Hisao Nakagawa
- 👤 Shoji Koyama
- 👤 Hideshi Kataoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:26
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/02; H05B3/03; H01; H01C; H01C1/00; H01C1/14; H01C1/1406; H05B3/10; H05B3/12; H05B3/14; H05B3/141
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
109 words
A heating element comprising a semiconductor ceramic body of a honeycomb column-shaped structure, having flat perforated end surfaces and through-holes perpendicular thereto defining partitions, the material of said semiconductor ceramic body having a positive temperature coefficient of resistance over a Curie point and composed of barium titanate, wherein a pair of electric conductive layers are connected to the flat, perforated end surfaces of said semiconductor ceramic body and are electrically connected to a source for supplying power to said semiconductor ceramic body, and wherein at least one of said electric conductive layers is a non-ohmic electrode consisting of an adhesive oxide and an electrically conductive metal which is silver.
Claim 2
Dependent Claim
109 words
A heating element comprising a semiconductor ceramic body of a honeycomb column-shaped structure, having flat perforated end surfaces and through-holes perpendicular thereto defining partitions, the material of said semiconductor ceramic body having a positive temperature coefficient of resistance over a Curie point and composed of barium titanate, wherein a pair of electric conductive layers are connected to the flat, perforated end surfaces of said semiconductor ceramic body and are electrically connected to a source for supplying power to said semiconductor ceramic body, and wherein at least one of said electric conductive layers is a non-ohmic electrode consisting of an adhesive oxide and an electrically conductive metal which is silver.
Claim 3
Dependent Claim
34 words
A heating apparatus according to claim 1, wherein said electrically conductive metal is contained in said non-ohmic electrode in an amount of from 90 to 99% by weight, the balance being said adhesive oxide.
Claim 4
Dependent Claim
20 words
A heating apparatus according to claim 2, wherein said non-ohmic electrode has a thickness of from 7 to 30 microns.
Claim 5
Dependent Claim
42 words
A heating element according to claim 2, wherein the thickness of the partions of said through-holes is from 0.20 to 0.45 mm, and the area of said through-holes relative to the total surface of said semiconductor body is from 30 to 70%.
References Cited (Backward Citations)
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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) | 1990-03-30 | 1990-09-29 | 1991-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-30 | 1994-09-29 | 1995-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-30 | 1998-09-29 | 1999-03-31 | $7700.00 | Window Closed / Lapsed |