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US3882012A
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Oxygen sensors
Assignee: UK Secretary of State for Defence
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Filing: 1973-11-26
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Granted: 1975-05-06
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Expires: 1993-11-26
Abstract
Abstract In oxygen sensors of the type wherein a barrier separates the cathode from the environment, the anode or reference electrode is either a soluble product electrode (for example silver) immersed in a salt electrolyte or a reactive electrode such as a molten alkali metal, separated from the molten salt electrolyte of the sensor by a membrane of ionically conducting solid through which cations of the salt electrolyte or of the reactive electrode can be transported.
Inventors
- 👤 Thomas Dickinson
- 👤 Lynden John Greenley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:46
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/404
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
212 words
AN OXYGEN SENSOR COMPRISING AN ELECTROCHEMICAL CELL HAVING A SALT ELECTROLYTE WHICH IS MOLTEN AT THE TEMPERATURE OF OPERATION OF THE SENSOR, A GAS DIFFUSION ELECTRODE AS CATHODE, THE GAS DIFFUSION ELECTRODE INCLUDING A POROUS METAL LAYER AND A BARRIER LAYER SUBSTANTIALLY NON-POROUS TO THE ELECTROLYTE BUT POROUS TO OXYGEN INTERPOSED BETWEEN THE POROUS METAL LAYER AND THE ENVIROMENT OF THE SENSOR, A COUNTER ELECTRODE AS ANODE, MEASURING MEANS TO DETERMINE THE ELECTRICAL CURRENT WHICH FLOWS BETWEEN THE ANODE AND CATHODE OF THE ELECTROCHEMICAL CELL DUE TO OXYGEN IN THE ENVIRONMENT AND WHEREIN THE ELECTROCHEMICAL CELL INCLUDES AN ELECTRODE CONSTITUTING EITHER THE ANODE OR A REFERENCE ELECTRODE OF THE ELECTROCHEMICAL CELL, THE SAID ELECTRODE COMPRISING EITHER (A) A SOLUBLE PRODUCT ELECTRODE IMMERSED IN A SALT ELECTROLYTE WHICH IS MOLTEN AT THE TEMPERATURE OF OPERATION OF THE SENSOR OR (B) A REACTIVE ELECTRODE AND THE SAID ELECTRODE BEING SEPARATED FROM THE SALT ELECTROLYTE OF THE ELECTROCHEMICAL CELL BY A MEMBRANE OF IONICALLY CONDUCTING SOLID THROUGH WHICH CATIONS OF THE SALT ELECTROLYTE OR CATIONS OF THE REACTIVE ELECTRODE RESPECTIVELY CAN BE TRANSPORTED AND PROVIDED THAT WHEN A SEPARATE REFERENCE ELECTRODE IS INCLUDED A MEANS IS PROVIDED BY WHICH A CONSTANT POTENTIAL IS MAINTAINED BETWEEN THE GAS DIFFUSION ELECTRODE AND THE SAID SEPARATE REFERENCE ELECTRODE.
Claim 2
Dependent Claim
212 words
AN OXYGEN SENSOR COMPRISING AN ELECTROCHEMICAL CELL HAVING A SALT ELECTROLYTE WHICH IS MOLTEN AT THE TEMPERATURE OF OPERATION OF THE SENSOR, A GAS DIFFUSION ELECTRODE AS CATHODE, THE GAS DIFFUSION ELECTRODE INCLUDING A POROUS METAL LAYER AND A BARRIER LAYER SUBSTANTIALLY NON-POROUS TO THE ELECTROLYTE BUT POROUS TO OXYGEN INTERPOSED BETWEEN THE POROUS METAL LAYER AND THE ENVIROMENT OF THE SENSOR, A COUNTER ELECTRODE AS ANODE, MEASURING MEANS TO DETERMINE THE ELECTRICAL CURRENT WHICH FLOWS BETWEEN THE ANODE AND CATHODE OF THE ELECTROCHEMICAL CELL DUE TO OXYGEN IN THE ENVIRONMENT AND WHEREIN THE ELECTROCHEMICAL CELL INCLUDES AN ELECTRODE CONSTITUTING EITHER THE ANODE OR A REFERENCE ELECTRODE OF THE ELECTROCHEMICAL CELL, THE SAID ELECTRODE COMPRISING EITHER (A) A SOLUBLE PRODUCT ELECTRODE IMMERSED IN A SALT ELECTROLYTE WHICH IS MOLTEN AT THE TEMPERATURE OF OPERATION OF THE SENSOR OR (B) A REACTIVE ELECTRODE AND THE SAID ELECTRODE BEING SEPARATED FROM THE SALT ELECTROLYTE OF THE ELECTROCHEMICAL CELL BY A MEMBRANE OF IONICALLY CONDUCTING SOLID THROUGH WHICH CATIONS OF THE SALT ELECTROLYTE OR CATIONS OF THE REACTIVE ELECTRODE RESPECTIVELY CAN BE TRANSPORTED AND PROVIDED THAT WHEN A SEPARATE REFERENCE ELECTRODE IS INCLUDED A MEANS IS PROVIDED BY WHICH A CONSTANT POTENTIAL IS MAINTAINED BETWEEN THE GAS DIFFUSION ELECTRODE AND THE SAID SEPARATE REFERENCE ELECTRODE.
Claim 3
Dependent Claim
19 words
An oxygen sensor as claimed in claim 1 wherein the said electrode constitutes the anode of the electrochemical cell.
Claim 4
Dependent Claim
72 words
An oxygen sensor as claimed in claim 2 wherein the anode is a reactive electrode composed of a metal which is molten at the temperature of operation of the sensor and is selected from the group consisting of the alkali metals, the alkaline earth metals, alloys thereof and alloys containing at least one metal thereof and wherein the salt electrolyte of the electrochemical cell is substantially a mixture of alkali metal nitrates.
Claim 5
Dependent Claim
34 words
An oxygen sensor as claimed in claim 3 wherein the reactive electrode is an amalgam containing at least one metal selected from the group consisting of the alkali metals and the alkaline earth metals.
Claim 6
Dependent Claim
15 words
An oxygen sensor as claimed in claim 4 wherein the amalgam is a sodium amalgam.
Claim 7
Dependent Claim
30 words
An oxygen sensor as claimed in claim 3 wherein the reactive electrode is a metal selected from the group consisting of sodium, potassium and an alloy of sodium and potassium.
Claim 8
Dependent Claim
38 words
An oxygen sensor as claimed in claim 3 wherein the reactive electrode is a metal selected from the group consisting of sodium, lithium and alloys containing sodium or lithium and the ionically conducting solid is a Beta -alumina.
Claim 9
Dependent Claim
25 words
An oxygen sensor as claimed in claim 7 wherein the salt electrolyte of the electrochemical cell is a mixture of sodium, potassium and lithium nitrates.
Claim 10
Dependent Claim
21 words
An oxygen sensor as claimed in claim 8 wherein the mixture of sodium, potassium and lithium nitrates is an eutectic mixture.
Claim 11
Dependent Claim
36 words
An oxygen sensor as claimed in claim 9 wherein the eutectic mixture of sodium, potassium and lithium nitrates is the eutectic mixture having the composition NaNO3-30 moles percent, KNO3-53.5 moles percent and LiNO313 16.5 moles percent.
Claim 12
Dependent Claim
65 words
An oxygen sensor as claimed in claim 2 wherein the anode includes a soluble product electrode composed of a metal selected from the group consisting of silver, indium, bismuth, copper and alloys containing at least one metal thereof and wherein the salt electrolyte in which the soluble product is immersed and the salt electrolyte of the electrochemical cell are substantially mixtures of alkali metal nitrates.
Claim 13
Dependent Claim
30 words
An oxygen sensor as claimed in claim 11 wherein the soluble product electrode is a metal selected from the group consisting of silver, indium amalgam and an indium bismuth alloy.
Claim 14
Dependent Claim
26 words
An oxygen sensor as claimed in claim 1 in which the electrochemical cell includes a reference electrode and wherein the said electrode constitutes the reference electrode.
Claim 15
Dependent Claim
67 words
An oxygen sensor as claimed in claim 13 wherein the reference electrode includes a sOluble product electrode composed of a metal selected from the group consisting of silver, indium, bismuth, copper, and alloys containing at least one metal thereof and wherein the salt electrolyte in which the soluble product electrode is immersed and the salt electrolyte of the electrochemical cell are substantially mixtures of alkali metal nitrates.
Claim 16
Dependent Claim
30 words
An oxygen sensor as claimed in claim 14 wherein the soluble product electrode is a metal selected from the group consisting of silver, indium amalgam and an indium bismuth alloy.
Claim 17
Dependent Claim
29 words
An oxygen sensor as claimed in claim 15 wherein the salt electrolyte in which the soluble product electrode is immersed is a mixture of sodium, potassium and lithium nitrates.
Claim 18
Dependent Claim
17 words
An oxygen sensor as claimed in claim 16 wherein the ionically conducting solid is a Beta -alumina.
Claim 19
Dependent Claim
49 words
An oxygen sensor as claimed in claim 17 wherein the anode of the electrochemical cell is constructed from a metal which is stable in contact with the molten salt electrolyte of the electrochemical cell and capable of forming an oxide which is substantially unsoluble in the molten salt electrolyte.
Claim 20
Dependent Claim
25 words
An oxygen sensor as claimed in claim 18 wherein the anode is a metal selected from the group consisting of tin, zinc and alloys thereof.
Claim 21
Dependent Claim
21 words
An oxygen sensor as claimed in claim 19 wherein the mixture of sodium, potassium and lithium nitrates is an eutectic mixture.
Claim 22
Dependent Claim
34 words
An oxygen sensor as claimed in claim 20 wherein the eutectic of sodium, potassium and lithium nitrates is the eutectic mixture having the composition NaNO3-30 moles percent, KNO3-53.5 moles percent and LiNO3-16.5 moles percent.
Claim 23
Dependent Claim
72 words
An oxygen sensor as claimed in claim 13 wherein the reference electrode is a reactive electrode composed of a metal which is molten at the temperature of operation of the sensor and is selected from the group consisting of alkali metal, the alkaline earth metals, alloys thereof and alloys containing at least one metal thereof and wherein the salt electrolyte of the electrochemical cell is substantially a mixture of alkali metal nitrates.
Claim 24
Dependent Claim
34 words
An oxygen sensor as claimed in claim 22 wherein the reactive electrode is an amalgam containing at least one metal selected from the group consisting of the alkali metals and the alkaline earth metals.
Claim 25
Dependent Claim
15 words
An oxygen sensor as claimed in claim 23 wherein the amalgam is a sodium amalgam.
Claim 26
Dependent Claim
30 words
An oxygen sensor as claimed in claim 22 wherein the reactive electrode is a metal selected from the group consisting of sodium, potassium and an alloy of sodium and potassium.
Claim 27
Dependent Claim
38 words
An oxygen sensor as claimed in claim 22 wherein the reactive electrode is a metal selected from the group consisting of sodium, lithium and alloys containing lithium or sodium and the ionically conducting solid is a Beta -alumina.
References Cited (Backward Citations)
US3404036A
Cited
US3689394A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |