US4197089A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reducing gas sensor
Assignee: Ambac Industries Inc
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Filing: 1978-01-18
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Granted: 1980-04-08
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Expires: 1998-01-18
Abstract
Abstract A sensor for the quantitative determination of reduction of a gas in which a thin tungsten oxide film detector element includes means for providing a specificity for the gas to be detected with respect to other gases. If ammonia is to be detected, a platinum catalyst is utilized. If hydrogen sulfide is to be detected, tungsten trioxide is used in the film.
Inventors
- 👤 Alexander N. Willis
- 👤 Margers Silarajs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:48
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; Y; Y10; Y10T; Y10T436/00; Y10T436/17; Y10T436/173845; Y10T436/175383; Y10T436/18; Y10T436/182; Y10T436/184
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
96 words
A method of monitoring the hydrogen sulfide content of a gaseous atmosphere which comprises the steps of exposing to said atmosphere a thin film semiconductor coated on an inert refractory substrate, said film being comprised of tungsten trioxide, without a dopant to provide hydrogen sulfide specificity, and diminishing in resistivity with increasing atmospheric concentration of hydrogen sulfide when placed at from about 150° C. to about 300° C. in an air atmosphere containing at least hydrogen sulfide, monitoring the conductivity of said film, and generating a signal proportional to the conductivity of said film so monitored.
Claim 2
Independent Claim
96 words
A method of monitoring the hydrogen sulfide content of a gaseous atmosphere which comprises the steps of exposing to said atmosphere a thin film semiconductor coated on an inert refractory substrate, said film being comprised of tungsten trioxide, without a dopant to provide hydrogen sulfide specificity, and diminishing in resistivity with increasing atmospheric concentration of hydrogen sulfide when placed at from about 150° C. to about 300° C. in an air atmosphere containing at least hydrogen sulfide, monitoring the conductivity of said film, and generating a signal proportional to the conductivity of said film so monitored.
Claim 3
Independent Claim
81 words
A method of detecting hydrogen sulfide in a gaseous atmosphere comprising: heating a thin film of tungsten trioxide between about 150° C. and about 300° C., exposing the tungsten trioxide film to the gaseous atmosphere to be monitored, detecting any change in electrical conductivity of the tungsten trioxide film when so exposed, and generating a signal proportional to the change in conductivity, said method characterized in the exclusion from said tungsten trioxide film of a dopant to provide hydrogen sulfide sensitivity.
Claim 4
Independent Claim
81 words
A method of detecting hydrogen sulfide in a gaseous atmosphere comprising: heating a thin film of tungsten trioxide between about 150° C. and about 300° C., exposing the tungsten trioxide film to the gaseous atmosphere to be monitored, detecting any change in electrical conductivity of the tungsten trioxide film when so exposed, and generating a signal proportional to the change in conductivity, said method characterized in the exclusion from said tungsten trioxide film of a dopant to provide hydrogen sulfide sensitivity.
Claim 5
Independent Claim
109 words
A method of monitoring the ammonia content of gaseous atmosphere which comprises the steps of exposing to said atmosphere a thin film semiconductor coated on an inert refractory substrate, said film having been deposited over a layer of platinum of a thickness of from about fifty to seventy Angstroms formed on the substrate and being principally comprised of a tungsten trioxide and diminishing in resistivity with increasing atmospheric concentration of ammonia when placed at from about 150° C. to about 300° C. in an air atmosphere containing at least ammonia, monitoring the conductivity of said film, and generating a signal proportional to the conductivity of said film so monitored.
Claim 6
Independent Claim
109 words
A method of monitoring the ammonia content of gaseous atmosphere which comprises the steps of exposing to said atmosphere a thin film semiconductor coated on an inert refractory substrate, said film having been deposited over a layer of platinum of a thickness of from about fifty to seventy Angstroms formed on the substrate and being principally comprised of a tungsten trioxide and diminishing in resistivity with increasing atmospheric concentration of ammonia when placed at from about 150° C. to about 300° C. in an air atmosphere containing at least ammonia, monitoring the conductivity of said film, and generating a signal proportional to the conductivity of said film so monitored.
Claim 7
Dependent Claim
65 words
In a gas sensor, a semiconductive element connected between a pair of sensor output terminals and containing tungsten trioxide in a concentration sufficient to provide a specificity in sensitivity for hydrogen sulfide with respect to other gases which has been deposited over a layer of platinum present in a concentration sufficient to provide a specificity of said element for ammonia with respect to hydrogen sulfide.
Claim 8
Dependent Claim
65 words
In a gas sensor, a semiconductive element connected between a pair of sensor output terminals and containing tungsten trioxide in a concentration sufficient to provide a specificity in sensitivity for hydrogen sulfide with respect to other gases which has been deposited over a layer of platinum present in a concentration sufficient to provide a specificity of said element for ammonia with respect to hydrogen sulfide.
Claim 9
Dependent Claim
105 words
A sensor having a specificity in sensitivity for ammonia with respect to other reducing gases comprising: a base of nonconducting material; a layer of platinum catalyst deposited on said base; a reducing film formed on said base over the platinum catalyst and containing tungsten oxide as its principal constituent; means for heating said film to a temperature at which the catalytic reduction of ammonia occurs; means for measuring changes in resistance in said film in response to reduction reactions occurring at the film surface; and in which the platinum is deposited on the base in a thickness of from about fifty to about seventy Angstroms.
Claim 10
Dependent Claim
105 words
A sensor having a specificity in sensitivity for ammonia with respect to other reducing gases comprising: a base of nonconducting material; a layer of platinum catalyst deposited on said base; a reducing film formed on said base over the platinum catalyst and containing tungsten oxide as its principal constituent; means for heating said film to a temperature at which the catalytic reduction of ammonia occurs; means for measuring changes in resistance in said film in response to reduction reactions occurring at the film surface; and in which the platinum is deposited on the base in a thickness of from about fifty to about seventy Angstroms.
Claim 11
Dependent Claim
122 words
A sensor having a specificity in sensitivity for ammonia with respect to other reducing gases comprising: a base of a nonconducting material over a portion of which a layer of platinum of from about fifty to about seventy Angstroms in thickness has been deposited; a reducing film formed over the platinum layer deposited on said base, said film being comprised at least in part of tungsten trioxide in a concentration sufficient, absent said platinum, to provide a film with hydrogen sulfide specificity with respect to ammonia; means for heating said film to a temperature at which the catalytic reduction of ammonia occurs; and means for measuring changes in resistance in said film in response to reduction reactions occurring at the film surface.
Claim 12
Dependent Claim
122 words
A sensor having a specificity in sensitivity for ammonia with respect to other reducing gases comprising: a base of a nonconducting material over a portion of which a layer of platinum of from about fifty to about seventy Angstroms in thickness has been deposited; a reducing film formed over the platinum layer deposited on said base, said film being comprised at least in part of tungsten trioxide in a concentration sufficient, absent said platinum, to provide a film with hydrogen sulfide specificity with respect to ammonia; means for heating said film to a temperature at which the catalytic reduction of ammonia occurs; and means for measuring changes in resistance in said film in response to reduction reactions occurring at the film surface.
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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) | 1983-04-08 | 1983-10-08 | 1984-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-08 | 1987-10-08 | 1988-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-08 | 1991-10-08 | 1992-04-08 | $7700.00 | Window Closed / Lapsed |