US4063898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combustible gases detector
Assignee: Elsag International BV
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Filing: 1976-09-20
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Granted: 1977-12-20
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Expires: 1996-09-20
Abstract
Abstract A differential thermocouple combustible gas detector is provided by coating one thermocouple junction of a differential thermocouple pair with a catalyst and the other thermocouple junction with a non-catalyst. Heated combustible gases react with the catalyst to liberate heat to the catalyst coated thermocouple junction in proportion to the concentration of combustible gases and proportionally raise the temperature of that junction above the non-catalyst coated junction. The output signal from the differential thermocouple device is thus a signal indicative of the concentration of combustible gases.
Inventors
- 👤 Edward William Fisher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:22
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/20; G01N25/22; G01N25/28; G01N25/30; G01N25/32; Y; Y10; Y10T; Y10T436/00; Y10T436/20; Y10T436/204998; Y10T436/205831; Y10T436/21; Y10T436/214
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
142 words
A detector for monitoring combustible gases in an airstream comprising: a first thermocouple junction located in the airstream; a second thermocouple junction located in the airstream and connected to said first thermocouple to form a differential thermocouple; catalytic means formed around said first thermocouple junction allowing heated combustibles in the airstream to react with said catalytic means to liberate heat and increase the temperature of said first thermocouple above that of said second thermocouple; insulation means formed around said second thermocouple junction to prevent combustibles in the airstream from reacting with said second thermocouple junction to liberate heat including a tube of non-catalytic material mounted on said second thermocouple junction with a non-catalytic cement material formed around said non-catalytic tube; and means connected to said first and second thermocouple junctions for indicating the temperature differential between said first and second thermocouple junctions.
Claim 2
Dependent Claim
142 words
A detector for monitoring combustible gases in an airstream comprising: a first thermocouple junction located in the airstream; a second thermocouple junction located in the airstream and connected to said first thermocouple to form a differential thermocouple; catalytic means formed around said first thermocouple junction allowing heated combustibles in the airstream to react with said catalytic means to liberate heat and increase the temperature of said first thermocouple above that of said second thermocouple; insulation means formed around said second thermocouple junction to prevent combustibles in the airstream from reacting with said second thermocouple junction to liberate heat including a tube of non-catalytic material mounted on said second thermocouple junction with a non-catalytic cement material formed around said non-catalytic tube; and means connected to said first and second thermocouple junctions for indicating the temperature differential between said first and second thermocouple junctions.
Claim 3
Dependent Claim
22 words
A detector as set forth in claim 1 wherein said catalytic means includes a platinum tube mounted on said first thermocouple junction.
Claim 4
Dependent Claim
22 words
A detector as set forth in claim 1 wherein said catalytic means includes a platinum paste baked onto said first thermocouple junction.
Claim 5
Dependent Claim
40 words
A detector as set forth in claim 1 wherein said catalytic means includes a platinum tube mounted on said first thermocouple junction and a coating of platinum paste baked onto said platinum tube to increase the catalytic surface area thereby.
Claim 6
Dependent Claim
45 words
A detector as set forth in claim 1 including heater means for maintaining the temperature of said first and said second thermocouple junctions above a predetermined temperature below which combustibles in the airstream will not react with the catalytic means on said first thermocouple junction.
Claim 7
Dependent Claim
24 words
A detector as set forth in claim 5 wherein said heater means includes a coil heater mounted around said first and second thermocouple junction.
Claim 8
Dependent Claim
31 words
A detector as set forth in claim 6 wherein said coil heater is coated with a non-catalytic cement material to prevent combustibles in the airstream from reacting with the heater material.
Claim 9
Dependent Claim
158 words
A differential thermocouple device for detecting carbon monoxide in air comprising: a first thermocouple junction formed from dissimilar metals; a second thermocouple junction formed form the same dissimilar metals as said first thermocouple and being electrically connected to said first thermocouple to oppose the electrical output signal of said first thermocouple; a catalytic material tube mounted on said first thermocouple junction to react with the carbon monoxide in the air to liberate heat in proportion to the concentration of carbon monoxide and increase the temperature of said first thermocouple junction located in said catalytic material tube; a non-catalytic material tube located on said second thermocouple junction to prevent any reaction with the carbon monoxide in the air at the second thermocouple junction; and detection means connected to said first and said second thermocouple junctions to provide an output responsive to the temperature difference between said first and second thermocouple junctions to indicate the concentration of carbon monoxide thereby.
Claim 10
Dependent Claim
158 words
A differential thermocouple device for detecting carbon monoxide in air comprising: a first thermocouple junction formed from dissimilar metals; a second thermocouple junction formed form the same dissimilar metals as said first thermocouple and being electrically connected to said first thermocouple to oppose the electrical output signal of said first thermocouple; a catalytic material tube mounted on said first thermocouple junction to react with the carbon monoxide in the air to liberate heat in proportion to the concentration of carbon monoxide and increase the temperature of said first thermocouple junction located in said catalytic material tube; a non-catalytic material tube located on said second thermocouple junction to prevent any reaction with the carbon monoxide in the air at the second thermocouple junction; and detection means connected to said first and said second thermocouple junctions to provide an output responsive to the temperature difference between said first and second thermocouple junctions to indicate the concentration of carbon monoxide thereby.
Claim 11
Dependent Claim
27 words
A device as set forth in claim 8 including a coating of platinum paste baked onto said catalytic material tube to increase the catalytic surface area thereby.
Claim 12
Dependent Claim
19 words
A device as set forth in claim 9 including a non-catalytic cement material formed around said non-catalytic material tube.
Claim 13
Dependent Claim
45 words
A device as set forth in claim 10 including heater means for maintaining the temperature of said first and said second thermocouple junctions above a predetermined temperature below which combustibles in the airstream will not react with the catalytic means on said first thermocouple junction.
Claim 14
Dependent Claim
24 words
A device as set forth in claim 11 wherein said heater means includes a coil heater mounted around said first and second thermocouple junction.
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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) | 1980-12-19 | 1981-06-20 | 1981-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-19 | 1985-06-20 | 1985-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-19 | 1989-06-20 | 1989-12-20 | $7700.00 | Window Closed / Lapsed |