US4242302A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a catalytic combustion type gas detector
Assignee: Shibaura Electronics Co Ltd
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Filing: 1978-08-23
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Granted: 1980-12-30
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Expires: 1998-08-23
Abstract
Abstract A method is described of making a catalytic combustion type gas detector, the sensitivity of which to alcohol vapors and to tobacco fumes is decreased by utilizing a mixture of powders. The mixed powders is composed of at least one metal oxide selected from TiO2, ZrO2, Y2O3, HfO2, CeO2, La2O3, NiO Cr2O3 and a substance which presents an N-type semiconductor characteristic by gas adsorption. The mixture is coated directly on a wire coil of Pt or the like and a current is applied to the metal wire coil in an oxidizing atmosphere to sinter the coated mixed powder thereon.
Inventors
- 👤 Kenzo Kitamura
- 👤 Hideaki Ebitani
- 👤 Masahiro Asakura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:39
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/14; G01N27/16; Y; Y10; Y10T; Y10T436/00; Y10T436/20; Y10T436/203332; Y10T436/204165
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
171 words
A method of making a gas detector comprising the steps of: mixing at least one powdered metal oxide selected from the group consisting of TiO 2 , ZrO 2 , Y 2 O 3 , HfO 2 , CeO 2 , La 2 O 3 , NiO and Cr 2 O 3 with a powdered substance which exhibits an N-type semiconductor characteristic by gas adsorption and which is selected from the group consisting of ZnO, SnO and In 2 O 3 , said powdered substance being in an amount of less than 40% by weight, based on the total weight of the powders; coating the thus mixed powders on a wire coil of a metal which is difficult to become oxidized at elevated temperatures; and applying an electric current to said metal wire coil in an oxidizing atmosphere to sinter the thus coated wire coil, the mean temperature of said wire coil during sintering being greater than 1000° C. but lower than the melting point of the said metal wire coil.
Claim 2
Independent Claim
171 words
A method of making a gas detector comprising the steps of: mixing at least one powdered metal oxide selected from the group consisting of TiO 2 , ZrO 2 , Y 2 O 3 , HfO 2 , CeO 2 , La 2 O 3 , NiO and Cr 2 O 3 with a powdered substance which exhibits an N-type semiconductor characteristic by gas adsorption and which is selected from the group consisting of ZnO, SnO and In 2 O 3 , said powdered substance being in an amount of less than 40% by weight, based on the total weight of the powders; coating the thus mixed powders on a wire coil of a metal which is difficult to become oxidized at elevated temperatures; and applying an electric current to said metal wire coil in an oxidizing atmosphere to sinter the thus coated wire coil, the mean temperature of said wire coil during sintering being greater than 1000° C. but lower than the melting point of the said metal wire coil.
Claim 3
Dependent Claim
21 words
The method according to claim 1, which is for making a detector which is selective for alcohol fumes and tobacco fumes.
Claim 4
Dependent Claim
28 words
The method according to claim 1 wherein said amount of said powdered substance ranges between 10 and 35% by weight, based on the total weight of the powders.
Claim 5
Dependent Claim
161 words
A gas detector which comprises: (a) a wire coil of a metal which is difficult to become oxidized at elevated temperatures; (b) a pair of electric terminal conductors connected to said wire coil; (c) a mixture of a first powder and a second powder coated and sintered onto said wire coil; said first powder consisting of an oxide selected from the group consisting of TiO 2 , ZrO 2 , Y 2 O 3 , HfO 2 , CeO 2 , La 2 O 3 , NiO and Cr 2 O 3 , and said second powder consisting of an oxide selected from the group consisting of ZnO, SnO 2 and In 2 O 3 ; said second powder being in an amount of less than 40% by weight, based on the total weight of the mixture; (d) a stem-base for supporting rigidly thereon said terminal conductors; and (e) an encapsulating envelope enclosing said coated wire coil into an operating unit.
Claim 6
Dependent Claim
161 words
A gas detector which comprises: (a) a wire coil of a metal which is difficult to become oxidized at elevated temperatures; (b) a pair of electric terminal conductors connected to said wire coil; (c) a mixture of a first powder and a second powder coated and sintered onto said wire coil; said first powder consisting of an oxide selected from the group consisting of TiO 2 , ZrO 2 , Y 2 O 3 , HfO 2 , CeO 2 , La 2 O 3 , NiO and Cr 2 O 3 , and said second powder consisting of an oxide selected from the group consisting of ZnO, SnO 2 and In 2 O 3 ; said second powder being in an amount of less than 40% by weight, based on the total weight of the mixture; (d) a stem-base for supporting rigidly thereon said terminal conductors; and (e) an encapsulating envelope enclosing said coated wire coil into an operating unit.
Claim 7
Dependent Claim
15 words
The gas detector according to claim 4, for detecting selectively fumes of alcohol and tobacco.
Claim 8
Dependent Claim
30 words
The gas detector according to claim 4, wherein said second powder is in an amount of between 10 and 35% by weight, based on the total weight of the mixture.
References Cited (Backward Citations)
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 |