US3953173A
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Gas-sensor element and method for detecting oxidizable gas
Assignee: Hitachi Ltd
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Filing: 1973-07-05
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Granted: 1976-04-27
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Expires: 1993-07-05
Abstract
Abstract A gas-sensor element for detecting oxidizable gases and vapors such as alcohols for carbon monoxide, which is characterized by comprising a complex metal oxide having the K2MgF4-type crystal structure and represented by the general formula A2-xA'xBO4- delta , wherein A is at least one element selected from the group consisting of rare earth elements of the atomic numbers from 57 to 71, yttrium, and hafnium, A' is at least one element selected from the group consisting of alkaline earth metals and lithium, B is at least one element selected from the group consisting of transition elements of the atomic numbers from 21 to 30, 0 is oxygen, x is in the range of 0</=x</=2, and delta is a nonstoichiometric parameter.
Inventors
- 👤 Hidehito Obayashi
- 👤 Tetsuo Gejyo
- 👤 Tetsuichi Kudo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:07
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; Y; Y10; Y10T; Y10T436/00; Y10T436/20; Y10T436/200833; Y10T436/203332; Y10T436/204165; Y10T436/204998; Y10T436/205831
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
166 words
In a method for detecting the presence of a gaseous substance in a test gas comprising contacting the test gas with a sensor element whose resistance changes in the presence of said gaseous substance and measuring the resistance of said sensing element while said test gas is in contact therewith, the improvement wherein said gaseous substance is an oxidizable gas and further wherein said sensing element comprises a complex metal oxide having a perovskite-type crystal structure and represented by the general formula A 2-x A' x BO 4- .sub.δ, wherein A is at least one element selected from the group consisting of rare earth elements of the atomic numbers from 57 to 71, yttrium, and hafnium, A' is at least one 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, x is in the range of 0 ≦ x ≦ 2, and δ is a nonstoichiometric parameter.
Claim 2
Dependent Claim
166 words
In a method for detecting the presence of a gaseous substance in a test gas comprising contacting the test gas with a sensor element whose resistance changes in the presence of said gaseous substance and measuring the resistance of said sensing element while said test gas is in contact therewith, the improvement wherein said gaseous substance is an oxidizable gas and further wherein said sensing element comprises a complex metal oxide having a perovskite-type crystal structure and represented by the general formula A 2-x A' x BO 4- .sub.δ, wherein A is at least one element selected from the group consisting of rare earth elements of the atomic numbers from 57 to 71, yttrium, and hafnium, A' is at least one 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, x is in the range of 0 ≦ x ≦ 2, and δ is a nonstoichiometric parameter.
Claim 3
Dependent Claim
21 words
A method according to claim 1, wherein the complex metal oxide contains at least nickel as B in the general formula.
Claim 4
Dependent Claim
15 words
A method according to claim 1, wherein the oxidizable gas is vapor of an alcohol.
Claim 5
Dependent Claim
30 words
A method according to claim 1, wherein said oxidizable gas is allowed to come into contact with said sensing element at a temperature of about 100° to about 500° C.
Claim 6
Dependent Claim
29 words
A method according to claim 1, wherein the complex metal oxide represented by the general formula A 2-x A' x BO 4- .sub.δ contains at least lanthanum as A.
Claim 7
Dependent Claim
21 words
A method according to claim 5, wherein the complex metal oxide contains at least strontium as A' in the general formula.
Claim 8
Dependent Claim
21 words
A method according to claim 6, wherein the complex metal oxide contains at least nickel as B in the general formula.
Claim 9
Dependent Claim
28 words
A method for according to claim 1, wherein x in the general formula A 2-x A' x BO 4- .sub.δ is in the range of o <x <2.
Claim 10
Dependent Claim
21 words
A method according to claim 8, wherein the complex metal oxide contains at least lanthanum as A in the general formula.
Claim 11
Dependent Claim
21 words
A method according to claim 8, wherein the complex metal oxide contains at least nickel as B in the general formula.
Claim 12
Dependent Claim
15 words
A method according to claim 8, wherein the oxidizable gas is vapor of an alcohol.
Claim 13
Dependent Claim
27 words
A method according to claim 1, wherein detecting of the oxidizable gas is carried out by measuring the change in specific resistance of said complex metal oxide.
Claim 14
Dependent Claim
29 words
A method according to claim 12, wherein x in the general formula A 2-x A' x BO 4- .sub.δ is in the range of 0 < x < 2.
Claim 15
Dependent Claim
29 words
A method according to claim 12, wherein the complex metal oxide represented by the general formula A 2-x A' x BO 4- .sub.δ contains at least lanthanum as A.
Claim 16
Dependent Claim
21 words
A method according to claim 12, wherein the complex metal oxide contains at least strontium as A' in the general formula.
Claim 17
Dependent Claim
21 words
A method according to claim 12, wherein the complex metal oxide contains at least nickel as B in the general formula.
Claim 18
Dependent Claim
15 words
A method according to claim 12, wherein the oxidizable gas is vapor of an alcohol.
Claim 19
Dependent Claim
30 words
A method according to claim 12, wherein said oxidizable gas is allowed to come into contact with said sensing element at a temperature of about 100° to about 500° C.
Claim 20
Dependent Claim
46 words
A method according to claim 1, wherein detecting of the oxidizable gas is carried out by measuring the change in specific resistance of said complex metal oxide when the oxidizable gas contacting said metal oxide is oxidized or decomposed by catalytic action of said metal oxide.
Claim 21
Dependent Claim
29 words
A method according to claim 19, wherein x in the general formula A 2-x A' x BO 4- .sub.δ is in the range of 0 < x < 2.
Claim 22
Dependent Claim
29 words
A method according to claim 19, wherein the complex metal oxide represented by the general formula A 2-x A' x BO 4- .sub.δ contains at least lanthanum as A.
Claim 23
Dependent Claim
21 words
A method according to claim 19, wherein the complex metal oxide contains at least strontium as A' in the general formula.
Claim 24
Dependent Claim
21 words
A method according to claim 19, wherein the complex metal oxide contains at least nickel as B in the general formula.
Claim 25
Dependent Claim
15 words
A method according to claim 19, wherein the oxidizable gas is vapor of an alcohol.
Claim 26
Dependent Claim
30 words
A method according to claim 19, wherein said oxidizable gas is allowed to come into contact with said sensing element at a temperature of about 100° to about 500° C.
Claim 27
Dependent Claim
184 words
In a gas sensor for detecting the presence of an oxidizable gas in a test gas, said gas sensor including a sensing element whose resistance changes in the presence of the gas to be detected, said sensing element including a surface capable of coming into contact with said test gas and means for indicating the presence of said oxidizable gas in said test gas in response to a change in resistance of said sensing element, the improvement wherein said sensing element comprises a complex metal oxide having a K 2 MgF 4 -type crystal structure and represented by the general formula A 2-x A' x BO 4- .sub.δ, wherein A is at least one element selected from the group consisting of rare earth elements of the atomic numbers from 57 to 71, yttrium, and hafnium, A' is at least one alkaline earth metal, B is at least one element selected from the group consisting of transition elements of the atomic numbers 21 to 30, O is oxygen, x is in the range of 0 ≦ x ≦ 2, and δ is a nonstoichiometric parameter.
Claim 28
Dependent Claim
184 words
In a gas sensor for detecting the presence of an oxidizable gas in a test gas, said gas sensor including a sensing element whose resistance changes in the presence of the gas to be detected, said sensing element including a surface capable of coming into contact with said test gas and means for indicating the presence of said oxidizable gas in said test gas in response to a change in resistance of said sensing element, the improvement wherein said sensing element comprises a complex metal oxide having a K 2 MgF 4 -type crystal structure and represented by the general formula A 2-x A' x BO 4- .sub.δ, wherein A is at least one element selected from the group consisting of rare earth elements of the atomic numbers from 57 to 71, yttrium, and hafnium, A' is at least one alkaline earth metal, B is at least one element selected from the group consisting of transition elements of the atomic numbers 21 to 30, O is oxygen, x is in the range of 0 ≦ x ≦ 2, and δ is a nonstoichiometric parameter.
Claim 29
Dependent Claim
21 words
A gas-sensor according to claim 26, wherein the complex metal oxide contains at least nickel as B in the general formula.
Claim 30
Dependent Claim
15 words
A gas-sensor according to claim 26, wherein the oxidizable gas is vapor of an alcohol.
Claim 31
Dependent Claim
25 words
A gas sensor according to claim 26, further including means for maintaining said sensor element at a constant temperature between about 100° and 500° C.
Claim 32
Dependent Claim
20 words
The gas sensor of claim 26, wherein said sensing element is in the form of a plate, rod or disc.
Claim 33
Dependent Claim
17 words
The gas sensor of claim 26, wherein said complex metal oxide is a coating on a substrate.
Claim 34
Dependent Claim
29 words
A gas-sensor according to claim 26, wherein the complex metal oxide represented by the general formula A 2-x A' x BO 4- .sub.δ contains at least lanthanum as A.
Claim 35
Dependent Claim
21 words
A gas-sensor according to claim 32, wherein the complex metal oxide contains at least strontium as A' in the general formula.
Claim 36
Dependent Claim
21 words
A gas-sensor according to claim 33, wherein the complex metal oxide contains at least nickel as B in the general formula.
Claim 37
Dependent Claim
27 words
A gas-sensor according to claim 26, wherein x in the general formula A 2-x A' x BO 4- .sub.δ is in the range of 0 <x <2.
Claim 38
Dependent Claim
21 words
A gas-sensor according to claim 35, wherein the complex metal oxide contains at least lanthanum as A in the general formula.
Claim 39
Dependent Claim
21 words
A gas-sensor according to claim 35, wherein the complex metal oxide contains at least nickel as B in the general formula.
Claim 40
Dependent Claim
15 words
A gas-sensor according to claim 35, wherein the oxidizable gas is vapor of an alcohol.
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) | 1979-04-27 | 1979-10-27 | 1980-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-27 | 1983-10-27 | 1984-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-27 | 1987-10-27 | 1988-04-27 | $7700.00 | Window Closed / Lapsed |