Patent US4242303A successfully refreshed from Google Patents.
US4242303A
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Gas detecting element
Assignee: Toshiba Corp
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Filing: 1979-04-25
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Granted: 1980-12-30
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Expires: 1999-04-25
Abstract
Abstract A gas detecting element having a high gas selectivity which comprises an N-type metal oxide semiconductor, 0.005 to 8% by weight, based on the metal oxide, of at least one noble metal catalyst selected from the group consisting of platinum (Pt), palladium (Pd) and rhodium (Rh) and phosphorus 1.5 to 30 times as much as that of the noble metal or 0.05 to 30 times as much as that of palladium where palladium alone is used as the noble metal catalyst.
Inventors
- 👤 Takashi Takahashi
- 👤 Masaki Katsura
- 👤 Tadao Kaneda
- 👤 Hideaki Hiraki
- 👤 Masayuki Shiratori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:37
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; Y; Y10; Y10T; Y10T436/00; Y10T436/20; Y10T436/203332; Y10T436/204165; Y10T436/21; Y10T436/214; Y10T436/216
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
128 words
A gas detecting element comprising a hollow cylindrical insulative body, a pair of electrodes provided on the outer circumference of said insulative body and a gas sensitive material layer covering up the outer periphery of said insulative body and said electrodes, wherein the gas sensitive material layer comprises: an N-type metal oxide semiconductor; 0.005 to 8% by weight, based on the metal oxide, of at least one noble metal catalyst selected from the group consisting of platinum (Pt), palladium (Pd) and rhodium (Rh); and phosphorus in an amount of 1.5 to 30 times in mol ratio as much as that of the noble metal or 0.05 to 30 times in mol ratio as much as that of palladium where palladium alone is used as the noble metal catalyst.
Claim 2
Dependent Claim
128 words
A gas detecting element comprising a hollow cylindrical insulative body, a pair of electrodes provided on the outer circumference of said insulative body and a gas sensitive material layer covering up the outer periphery of said insulative body and said electrodes, wherein the gas sensitive material layer comprises: an N-type metal oxide semiconductor; 0.005 to 8% by weight, based on the metal oxide, of at least one noble metal catalyst selected from the group consisting of platinum (Pt), palladium (Pd) and rhodium (Rh); and phosphorus in an amount of 1.5 to 30 times in mol ratio as much as that of the noble metal or 0.05 to 30 times in mol ratio as much as that of palladium where palladium alone is used as the noble metal catalyst.
Claim 3
Dependent Claim
23 words
The gas detecting element according to claim 1, wherein the catalyst layer is formed on the surface of the N-type metal oxide semiconductor.
Claim 4
Dependent Claim
40 words
The gas detecting element according to claim 1, or wherein the N-type metal oxide semiconductor is provided by zinc oxide (ZnO) series materials, tin oxide (SnO 2 ) series materials or iron oxide (Fe 2 O 3 ) series materials.
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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) | 1983-12-30 | 1984-06-30 | 1984-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-30 | 1988-06-30 | 1988-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-30 | 1992-06-30 | 1992-12-30 | $7700.00 | Window Closed / Lapsed |