US4044601A
Expired / Lapsed
US
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Smoke and gas sensor element
Assignee: Hitachi Ltd
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Filing: 1975-07-29
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Granted: 1977-08-30
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Expires: 1995-07-29
Abstract
Abstract A sensor element for detecting smoke and/or reducing gases, which comprises a shaped body formed from a material consisting essentially of:
Inventors
- 👤 Yo Sakurai
- 👤 Hidehito Obayashi
- 👤 Tetsuo Gejyo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:30
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
198 words
In a sensor device for detecting the presence of smoke and/or a gaseous substance in an atmosphere, said sensor device including a sensor element whose resistance changes with the presence of said smoke or gaseous substance, said sensor element having a surface capable of coming into contact with said atmosphere and a means for indicating the presence of said smoke or gaseous substance in said atmosphere in response to a change in the resistance of said sensor element, the improvement wherein said sensor element is formed from a material comprising: 1. a complex metal oxide having a perovskite type crystal structure and represented by the general formula ABO 3- .sub.δ, wherein A is at least one element selected from the group consisting of yttrium, a rare earth element of an atomic number from 57 to 71, and an alkaline earth metal, B is at least one element selected from the group consisting of transition metals of the atomic numbers from 21 to 30, O is oxygen and δ is a nonstoichiometric parameter, and 2. at least one metal oxide selected from the group consisting of CdO, In 2 O 3 , SnO, Tl 2 O 3 and PbO.
Claim 2
Dependent Claim
198 words
In a sensor device for detecting the presence of smoke and/or a gaseous substance in an atmosphere, said sensor device including a sensor element whose resistance changes with the presence of said smoke or gaseous substance, said sensor element having a surface capable of coming into contact with said atmosphere and a means for indicating the presence of said smoke or gaseous substance in said atmosphere in response to a change in the resistance of said sensor element, the improvement wherein said sensor element is formed from a material comprising: 1. a complex metal oxide having a perovskite type crystal structure and represented by the general formula ABO 3- .sub.δ, wherein A is at least one element selected from the group consisting of yttrium, a rare earth element of an atomic number from 57 to 71, and an alkaline earth metal, B is at least one element selected from the group consisting of transition metals of the atomic numbers from 21 to 30, O is oxygen and δ is a nonstoichiometric parameter, and 2. at least one metal oxide selected from the group consisting of CdO, In 2 O 3 , SnO, Tl 2 O 3 and PbO.
Claim 3
Dependent Claim
25 words
A sensor according to claim 1, wherein the complex metal oxide represented by the general formula ABO 3- .sub.δ contains at least lanthanum as A.
Claim 4
Dependent Claim
25 words
A sensor according to claim 1, wherein the complex metal oxide represented by the general formula ABO 3- .sub.δ contains at least strontium as A.
Claim 5
Dependent Claim
25 words
A sensor according to claim 1, wherein the complex metal oxide represented by the general formula ABO 3- .sub.δ contains at least nickel as B.
Claim 6
Dependent Claim
21 words
A sensor according to claim 1, wherein said sensor element is in the form of a plate, rod, cylinder or disc.
Claim 7
Dependent Claim
15 words
The sensor according to claim 1, wherein said material is a coating on a substrate.
Claim 8
Dependent Claim
19 words
A sensor according to claim 6, wherein said substrate is in the form of a plate, rod or cylinder.
Claim 9
Dependent Claim
19 words
The sensor according to claim 1, further comprising a means for keeping the temperature of said sensor element constant.
Claim 10
Dependent Claim
31 words
A sensor according to claim 1, wherein said metal oxide (2) is more than 5% and less than 50% by weight, based on the weight of the complex metal oxide (1).
Claim 11
Dependent Claim
31 words
A sensor according to claim 9, wherein said metal oxide (2) is more than 5% or less than 30% by weight, based on the weight of the complex metal oxide (1).
Claim 12
Dependent Claim
173 words
In a method for detecting the presence of smoke and/or a gaseous substance in an atmosphere, comprising bringing the atmosphere into contact with a sensor element, whose resistance changes with the presence of said smoke and/or gaseous substance, and measuring the resistance of said sensor element while said atmosphere is in contact therewith, the improvement wherein said sensor element is formed from a material comprising (1), a complex metal oxide having a perovskite type crystal structure and represented by the general formula ABO 3- .sub.δ, wherein A is at least one element selected from the group consisting of yttrium, a rare earth element of an atomic number from 57 to 71 and an alkaline earth metal, B is at least one element selected from the group consisting of transition metals of the atomic numbers from 21 to 30, O is oxygen and δ is a nonstoichiometric parameter, and (2), at least one metal oxide selected from the group consisting of CdO, In 2 O 3 , SnO, Tl 2 O 3 and PbO.
Claim 13
Dependent Claim
173 words
In a method for detecting the presence of smoke and/or a gaseous substance in an atmosphere, comprising bringing the atmosphere into contact with a sensor element, whose resistance changes with the presence of said smoke and/or gaseous substance, and measuring the resistance of said sensor element while said atmosphere is in contact therewith, the improvement wherein said sensor element is formed from a material comprising (1), a complex metal oxide having a perovskite type crystal structure and represented by the general formula ABO 3- .sub.δ, wherein A is at least one element selected from the group consisting of yttrium, a rare earth element of an atomic number from 57 to 71 and an alkaline earth metal, B is at least one element selected from the group consisting of transition metals of the atomic numbers from 21 to 30, O is oxygen and δ is a nonstoichiometric parameter, and (2), at least one metal oxide selected from the group consisting of CdO, In 2 O 3 , SnO, Tl 2 O 3 and PbO.
Claim 14
Dependent Claim
30 words
A method according to claim 11, wherein the smoke and/or the gaseous substance is brought in contact with said sensor element at a temperature of about 100° to 500° C.
Claim 15
Dependent Claim
25 words
A method according to claim 11, wherein the complex metal oxide represented by the general formula ABO 3- .sub.δ contains at least lanthanum as A.
Claim 16
Dependent Claim
25 words
A method according to claim 11, wherein the complex metal oxide represented by the general formula ABO 3- .sub.δ contains at least strontium as A.
Claim 17
Dependent Claim
25 words
A method according to claim 11, wherein the complex metal oxide represented by the general formula ABO 3- .sub.δ contains at least nickel as B.
Claim 18
Dependent Claim
31 words
A method according to claim 11, wherein said metal oxide (2) is more than 5% and less than 50% by weight, based on the weight of the complex metal oxide (1).
Claim 19
Dependent Claim
31 words
A method according to claim 11, wherein said metal oxide (2) is more than 5% and less than 30% by weight based on the weight of the complex metal oxide (1).
Claim 20
Dependent Claim
14 words
A method according to claim 11, wherein the gaseous substance is a reducing gas.
Claim 21
Dependent Claim
16 words
A method according to claim 11, wherein the sensing element is maintained at a consant temperature.
Claim 22
Dependent Claim
142 words
A sensor element for detecting smoke and/or reducing gases, which comprises a shaped body or layer formed from a material consisting essentially of a mixtue of: A. a complex metal oxide having a perovskite type crystal structure and represented by the general formula ABO 3- .sub.δ wherein A is at least one element selected from the group consisting of yttrium, a rare earth element having an atomic number of from 57 to 71 and an alkaline earth metal, B is at least one element selected from the group consisting of transition metals having the atomic numbers from 21 to 30, O is oxygen and δ is a nonstoichiometric parameter which may vary from 0 to 0.25 and B. at least one metal oxide selected from the group consisting of CdO, In 2 O 3 , SnO, Tl 2 O 3 and PbO.
Claim 23
Dependent Claim
142 words
A sensor element for detecting smoke and/or reducing gases, which comprises a shaped body or layer formed from a material consisting essentially of a mixtue of: A. a complex metal oxide having a perovskite type crystal structure and represented by the general formula ABO 3- .sub.δ wherein A is at least one element selected from the group consisting of yttrium, a rare earth element having an atomic number of from 57 to 71 and an alkaline earth metal, B is at least one element selected from the group consisting of transition metals having the atomic numbers from 21 to 30, O is oxygen and δ is a nonstoichiometric parameter which may vary from 0 to 0.25 and B. at least one metal oxide selected from the group consisting of CdO, In 2 O 3 , SnO, Tl 2 O 3 and PbO.
Claim 24
Dependent Claim
35 words
A sensor element according to claim 20, wherein the amount of said metal oxide (B) within said mixture is from 5% to 50% by weight, based on the weight of the complex metal oxide (A).
Claim 25
Dependent Claim
35 words
A sensor element according to claim 20, wherein the amount of said metal oxide (B) within said mixture is from 5% to 30% by weight, based on the weight of the complex metal oxide (A).
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) | 1980-08-29 | 1981-02-28 | 1981-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-29 | 1985-02-28 | 1985-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-29 | 1989-02-28 | 1989-08-30 | $7700.00 | Window Closed / Lapsed |