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US4045178A
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Reducing gas sensor
Assignee: Panasonic Holdings Corp
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Filing: 1976-11-03
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Granted: 1977-08-30
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Expires: 1996-11-03
Abstract
Abstract This invention provides a reducing gas sensor which has a gas sensitive element composed of, as a main constituent, gamma -ferric oxide ( gamma -Fe2O3) and, as an additive, at least one compound in the group of WO3, MoO3, SiO2, GeO2, Li2O, Na2O, K2O, CaO, SrO, BaO, Eu2O3, La2O3, CeO2, Al2O3, Ga2O3, In2O3, SnO2, TiO2, MgO, NiO, ZnO, Mn2O3 and Cr2O3, a pair of electrodes and a heater element. The gamma -ferric oxide is in the form of a thin film, a plate or a thin surface layer on a sintered plate of gamma -ferric oxide. The gas sensor of the invention is much improved in the stability during use and also it has a high sensitivity.
Inventors
- 👤 Hideyuki Okinaka
- 👤 Atsushi Iga
- 👤 Masatake Ayusawa
- 👤 Masatugu Yamaguchi
- 👤 Seiichi Nakatani
- 👤 Toshiaki Yagami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:13
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
153 words
A reducing gas sensor comprising a gas sensitive element composed of, as a main constituent, γ-ferric oxide (γ-Fe 2 O 3 ) and, as an additive, at least one member selected from the group consisting of WO 3 , MoO 3 , SiO 2 , GeO 2 , Li 2 O, Na 2 O, K 2 O, CaO, SrO, BaO, Eu 2 O 3 , La 2 O 3 , CeO 2 , Al 2 O 3 , Ga 2 O 3 , In 2 O 3 , SnO 2 , TiO 2 , MgO, NiO, ZnO, Mn 2 O 3 and Cr 2 O 3 , a pair of electrodes on said sensitive element and a heater element adjacent said element, whereby when said gas sensitive element is heated to an elevated temperature it undergoes a rapid decrease in electrical resistance upon coming in contact with an atmosphere containing a reducing gas.
Claim 2
Dependent Claim
153 words
A reducing gas sensor comprising a gas sensitive element composed of, as a main constituent, γ-ferric oxide (γ-Fe 2 O 3 ) and, as an additive, at least one member selected from the group consisting of WO 3 , MoO 3 , SiO 2 , GeO 2 , Li 2 O, Na 2 O, K 2 O, CaO, SrO, BaO, Eu 2 O 3 , La 2 O 3 , CeO 2 , Al 2 O 3 , Ga 2 O 3 , In 2 O 3 , SnO 2 , TiO 2 , MgO, NiO, ZnO, Mn 2 O 3 and Cr 2 O 3 , a pair of electrodes on said sensitive element and a heater element adjacent said element, whereby when said gas sensitive element is heated to an elevated temperature it undergoes a rapid decrease in electrical resistance upon coming in contact with an atmosphere containing a reducing gas.
Claim 3
Dependent Claim
34 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 40.0 mol % of at least one member selected from the group consisting of WO 3 and MoO 3 .
Claim 4
Dependent Claim
34 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 40.0 mol % of at least one number selected from the group consisting of SiO 2 and GeO 2 .
Claim 5
Dependent Claim
38 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 10.0 mol % of at least one member selected from the group consisting of Li 2 O, Na 2 O and K 2 O.
Claim 6
Dependent Claim
32 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 20.0 mol % of at least one member selected from the group consisting of CaO, SrO and BaO.
Claim 7
Dependent Claim
41 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 20.0 mol % of at least one member selected from the group consisting of Eu 2 O 3 , La 2 O 3 and CeO 2 .
Claim 8
Dependent Claim
43 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 20.0 mol % of at least one member selected from the group consisting of Al 2 O 3 , Ga 2 O 3 and In 2 O 3 .
Claim 9
Dependent Claim
34 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 30.0 mol % of at least one member selected from the group consisting of SnO 2 and TiO 2 .
Claim 10
Dependent Claim
32 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 15.0 mol % of at least one member selected from the group consisting of MgO, NiO and ZnO.
Claim 11
Dependent Claim
38 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 15.0 mol % of at least one member selected from the group consisting of Mn 2 O 3 and Cr 2 O 3 .
Claim 12
Dependent Claim
39 words
A reducing gas sensor according to claim 1, wherein said additive is 0.1 to 20.0 mol % of at least one member selected from the group consisting of SrO and BaO or 0.1 to 15.0 mol % of MgO.
References Cited (Backward Citations)
US3695848A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-29 | 1981-02-28 | 1981-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-29 | 1985-02-28 | 1985-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-29 | 1989-02-28 | 1989-08-30 | $7700.00 | Window Closed / Lapsed |