Patent US4123225A successfully refreshed from Google Patents.
US4123225A
Expired / Lapsed
US
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Combustible gas detectors
Assignee: Teledyne UK Ltd
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Filing: 1977-07-05
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Granted: 1978-10-31
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Expires: 1997-07-05
Abstract
Abstract The invention provides a combustible gas detector in which a heatable wire filament embedded in a pellet comprising oxidation catalyst material exhibits a change in resistance occasioned by the change in its temperature which occurs due to the oxidation of a combustible gas passing over it. The pellet is provided with an outer layer of inert non-catalytic material which tends to prevent non-volatile residues from reaching catalytically active regions of the detector.
Inventors
- 👤 Eric Jones
- 👤 Rodney P. Townsend
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:27
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/14; G01N27/16
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
35 words
A gas detector comprising a heatable wire filament embedded in a pellet and provided with an outer layer of non-catalytic porous material tending to prevent non-volatile residues from reaching catalytically active regions of said detector.
Claim 2
Dependent Claim
35 words
A gas detector comprising a heatable wire filament embedded in a pellet and provided with an outer layer of non-catalytic porous material tending to prevent non-volatile residues from reaching catalytically active regions of said detector.
Claim 3
Dependent Claim
17 words
A detector as claimed in claim 1 and wherein said non-catalytic porous layer completely surrounds said pellet.
Claim 4
Dependent Claim
37 words
A detector as claimed in claim 1 and wherein said non-catalytic porous layer is of a material which is the same as a non-catalytic base carrier material used in the formation of the remainder of the pellet.
Claim 5
Dependent Claim
14 words
A detector as claimed in claim 1 and wherein said porous material is alumina.
Claim 6
Dependent Claim
17 words
A detector as claimed in claim 1 and wherein said non-catalytic porous layer comprises a zeolite material.
Claim 7
Dependent Claim
17 words
A detector as claimed in claim 1 and wherein said non-catalytic porous layer comprises an alumina/zeolite mixture.
Claim 8
Dependent Claim
27 words
A detector as claimed in claim 1 and wherein said pellet consists of a homogeneous mixture of an oxidation catalyst material and a substantially non-catalytic carrier material.
Claim 9
Dependent Claim
43 words
A detector as claimed in claim 7 and wherein a layer of oxidation catalyst material is provided on the outside of said pellet, said outer layer of non-catalytic porous material being provided on the outside of said last-mentioned layer of oxidation catalyst material.
Claim 10
Dependent Claim
97 words
A detector for a gas in the presence of non-volatile residue comprising, in combination: a heatable wire filament having a resistive characteristic which varies with temperature; catalytically active means surrounding said filament for altering the temperature of said filament in the presence of the gas to be detected; and an outer layer of inert porous material on said catalytically active means, said inert porous material being non-catalytic and being evaporatively deposited onto said catalytically active means whereby to preserve the non-catalytic nature of the outer layer and prevent the reaction of non-volatile residue with said outer layer.
Claim 11
Dependent Claim
97 words
A detector for a gas in the presence of non-volatile residue comprising, in combination: a heatable wire filament having a resistive characteristic which varies with temperature; catalytically active means surrounding said filament for altering the temperature of said filament in the presence of the gas to be detected; and an outer layer of inert porous material on said catalytically active means, said inert porous material being non-catalytic and being evaporatively deposited onto said catalytically active means whereby to preserve the non-catalytic nature of the outer layer and prevent the reaction of non-volatile residue with said outer layer.
Claim 12
Dependent Claim
15 words
A detector as defined in claim 9 wherein said inert porous material is a zeolite.
Claim 13
Dependent Claim
19 words
A detector as defined in claim 9 wherein said inert porous material comprises a mixture of alumina and zeolite.
Claim 14
Dependent Claim
44 words
A detector as defined in claim 9 wherein said catalytically active means comprises a pellet within which said filament is embedded, said pellet consisting of a homogeneous mixture of an oxidation catalyst material and a substantially non-catalytic carrier material evaporatively deposited onto said filament.
Claim 15
Dependent Claim
15 words
A detector as defined in claim 12 wherein said inert porous material is a zeolite.
Claim 16
Dependent Claim
19 words
A detector as defined in claim 12 wherein said inert porous material comprises a mixture of alumina and zeolite.
Claim 17
Dependent Claim
25 words
A detector as defined in claim 12 wherein said catalytically active means also includes a layer of oxidation catalyst material evaporatively deposited onto said pellet.
Claim 18
Dependent Claim
15 words
A detector as defined in claim 15 wherein said inert porous material is a zeolite.
Claim 19
Dependent Claim
19 words
A detector as defined in claim 15 wherein said inert porous material comprises a mixture of alumina and zeolite.
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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) | 1981-10-30 | 1982-05-01 | 1982-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-30 | 1986-05-01 | 1986-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-30 | 1990-05-01 | 1990-10-31 | $7700.00 | Window Closed / Lapsed |