US4556780A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic heater
Assignee: Denso Corp
•
Filing: 1984-10-11
•
Granted: 1985-12-03
•
Expires: 2004-10-11
Abstract
Abstract A ceramic heater comprises a heat generator made of a conductive ceramic sintered body, a supporter made of an insulating ceramic sintered body for supporting the heat generator, and a metallic wire for supplying an electric current from an electrode to the heat generator. The heat generator is integrally covered with an unporous covering layer made of an insulating ceramic sintered body. The covering layer prevents the heat generator from being directly exposed to oil and water. The covering layer is made of, for example Si 3 N 4 or glass containing SiO 2 as a main constituent into a thickness of not more than 1mm.
Inventors
- 👤 Morihiro Atsumi
- 👤 Hitoshi Yoshida
- 👤 Nobuei Ito
- 👤 Kinya Atsumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:08
CPC Classifications
F; F23; F23Q; F23Q7/00; F23Q7/001
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
110 words
A ceramic heater comprising: a heat generator made of a conductive ceramic sintered body; a supporter made of an insulating ceramic sintered body for supporting said heat generator; an unporous thin covering layer made of an insulating ceramic sintered body having a porosity of not more than 5% completely enclosing the outer surface of said heat generator, the covering ceramic layer preventing oxidation of said heat generator, improving the thermal shock resistance of said heat generator and preventing the heat generator from being directly exposed to water and oil; said ceramic sintered bodies being secured together; and electric current supply means for supplying an electric current to said heat generator.
Claim 2
Dependent Claim
110 words
A ceramic heater comprising: a heat generator made of a conductive ceramic sintered body; a supporter made of an insulating ceramic sintered body for supporting said heat generator; an unporous thin covering layer made of an insulating ceramic sintered body having a porosity of not more than 5% completely enclosing the outer surface of said heat generator, the covering ceramic layer preventing oxidation of said heat generator, improving the thermal shock resistance of said heat generator and preventing the heat generator from being directly exposed to water and oil; said ceramic sintered bodies being secured together; and electric current supply means for supplying an electric current to said heat generator.
Claim 3
Dependent Claim
28 words
A ceramic heater according to claim 1, wherein said heat generator is integrally sintered with said supporter while said heat generator is integrally sintered with said covering layer.
Claim 4
Dependent Claim
62 words
A ceramic heater according to claim 2, wherein said conductive ceramic sintered body is made of a material selected from the group consisting of MoSi 2 , TiO, TiN, a mixture of Si 3 N 4 and one of MoSi 2 , TiO, and TiN, and a mixture of Al 2 O 3 and one of MoSi 2 , TiO and, TiN.
Claim 5
Dependent Claim
40 words
A ceramic heater according to claim 2, wherein said insulating ceramic for forming said supporter is selected from the group consisting of Si 3 N 4 and a mixture of Si 3 N 4 and Al 2 O 3 .
Claim 6
Dependent Claim
55 words
A ceramic heater according to claim 2, wherein said insulating ceramic for forming said covering layer is selected from the group consisting of Si 3 N 4 , SiC, ZrO 2 , BN, and a mixture of Al 2 O 3 and one of Si 3 N 4 , SiC, ZrO 2 , and BN.
Claim 7
Dependent Claim
25 words
A ceramic heater according to claim 2, wherein said insulating ceramic for forming said covering layer is glass containing SiO 2 as the main constituent.
Claim 8
Dependent Claim
37 words
A ceramic heater according to claim 2, wherein said electric current supply means comprises an electrode and a metallic wire for connecting said electrode to said heat generator; and said metallic wire is embedded within said supporter.
Claim 9
Dependent Claim
19 words
A ceramic heater according to claim 2, wherein said covering layer has a porosity of not more than 2%.
Claim 10
Dependent Claim
20 words
A ceramic heater according to claim 2, wherein said covering layer has a thickness of not more than 1 mm.
Claim 11
Dependent Claim
19 words
A ceramic heater according to claim 5, wherein said covering layer has a thickness of 0.3 to 1 mm.
Claim 12
Dependent Claim
19 words
A ceramic heater according to claim 6, wherein said covering layer has a thickness of 0.005 to 0.5 mm.
Claim 13
Dependent Claim
38 words
A ceramic heater according to claim 3, wherein said heat generator is made of a sintered body of a mixture composed of 50 to 95 mol% of Si 3 N 4 with the remainder being MoSi 2 .
Claim 14
Dependent Claim
30 words
A ceramic heater according to claim 12, wherein said MoSi 2 for forming said heat generator has an average particle diameter smaller than that of Si 3 N 4 .
Claim 15
Dependent Claim
25 words
A ceramic heater according to claim 6, wherein said glass for forming said covering layer contains not less than 95 mol% of SiO 2 .
References Cited (Backward Citations)
US4357526A
Cited
US4401065A
Cited
US4458637A
Cited
US4449039A
Cited
US4486651A
Cited
US4475029A
Cited
US4499366A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-02 | 1989-06-03 | 1989-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-02 | 1993-06-03 | 1993-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-02 | 1997-06-03 | 1997-12-03 | $7700.00 | Window Closed / Lapsed |