US3835529A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas detecting device and method of making same
Assignee: Individual
•
Filing: 1972-04-24
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Granted: 1974-09-17
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Expires: 1992-04-24
Abstract
Abstract A gas detecting device formed of a porous, highly permeable, metal oxide semiconductor formed by mixing semiconductor particles with inorganic materials which will render the semiconductor highly porous or by intermixing the semiconductor with materials which can be evaporated or otherwise removed by heating to a temperature below the sintering temperature of the semiconductor. The resultant semiconductor material is contained within a suitable housing that will permit gases to flow readily through the semiconductor and appropriate electrodes are affixed to the semiconductor to measure a change in resistance in the presence of reducing gases. Heating means may be utilized to stabilize the resistance of the semiconductor material during operation and such heating means may comprise at least one of the electrodes.
Inventors
- 👤 N Taguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:23
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
124 words
A method of manufacturing a gas detecting device, comprising the steps of powdering a metal oxide semiconductor material which changes its electroconductivity when it contacts a reducing gas in the air, preparing a powder of a second material which can be removed at a temperature lower than the melting temperature or the sintering temperature of said powder of metal oxide semiconductor material, mixing said respective powders, pressshaping said mixture to form a block, heating said block to a temperature at which said metal oxide semiconductor material is not fused or sintered but said powder of said second material is removed to make said block porous, and attaching at least a pair of electrodes to two separate portions and in electrical contact with said block.
Claim 2
Independent Claim
124 words
A method of manufacturing a gas detecting device, comprising the steps of powdering a metal oxide semiconductor material which changes its electroconductivity when it contacts a reducing gas in the air, preparing a powder of a second material which can be removed at a temperature lower than the melting temperature or the sintering temperature of said powder of metal oxide semiconductor material, mixing said respective powders, pressshaping said mixture to form a block, heating said block to a temperature at which said metal oxide semiconductor material is not fused or sintered but said powder of said second material is removed to make said block porous, and attaching at least a pair of electrodes to two separate portions and in electrical contact with said block.
Claim 3
Dependent Claim
33 words
A method of manufacturing a gas detecting device, in accordance with claim 1, wherein said powder of second material is comprised of starch particles, such as fluor, crushed rice or dog-tooth violet starch.
Claim 4
Independent Claim
129 words
A method of manufacturing a gas detecting device, comprising the steps of powdering a metal oxide semiconductor material which changes its electroconductivity when it contacts a reducing gas in the air, mixing particles of quartz, alumina or similar inorganic particles which are coarser than the particles of said powder of metal oxide semiconductor material and have rough surfaces with said powdered metal oxide semiconductor material, shaping said mixture at a low temperature at which said mixture is neither fused nor sintered to form a block of said metal oxide semiconductor material, and attaching at least a pair of electrodes to two separate portions of said block and in electrical contact with said block, said course particles remaining unaffected by said heating and increasing surface area of the oxide powder.
Claim 5
Independent Claim
129 words
A method of manufacturing a gas detecting device, comprising the steps of powdering a metal oxide semiconductor material which changes its electroconductivity when it contacts a reducing gas in the air, mixing particles of quartz, alumina or similar inorganic particles which are coarser than the particles of said powder of metal oxide semiconductor material and have rough surfaces with said powdered metal oxide semiconductor material, shaping said mixture at a low temperature at which said mixture is neither fused nor sintered to form a block of said metal oxide semiconductor material, and attaching at least a pair of electrodes to two separate portions of said block and in electrical contact with said block, said course particles remaining unaffected by said heating and increasing surface area of the oxide powder.
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) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |