EP0060944A1
Expired / Lapsed
EP
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Sensor for oxygen-combustibles gas mixtures
Assignee: Westinghouse Electric Corp
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Filing: 1981-03-23
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Granted: —
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Expires: 2001-03-23
Abstract
Abstract A sensor for detecting the amount of O 2 and combustible gas in a gaseous mixture uses two electrochemical cells (20,40) operating in sequence, to detect oxygen and gaseous combustible contents respectively; the first electrochemical cell (20) is a molten carbonate electrochemical cell operating at a temperature between 400 and 700°C and is used to remove O 2 in combination with CO 2 from the oxygen/ combustibles gas mixture to provide a low temperature measurement of the oxygen content of the gas mixture. The second electrochemical cell (40) is an oxygen ion conductive using catalyzing electrodes (44,46) and an external source of O2, e.g. air, to cause combustion of the combustible components of the mixture. The cells (20, 40) each have electrodes (24,26;44,46) applied across cell-walls to apply a potential to cause oxygen transport across the cell walls. The current flowing through across the cell-walls in a measure of either the oxygen content or the oxygen required to oxidize the combustible gaseous contents.
Inventors
- 👤 Arnold Otto Isenberg
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 15:18
CPC Classifications
H; H01; H01M; H01M8/00; H01M8/14; H01M8/141; H01M8/142; G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/406; G01N27/407; G01N27/4073; G01N27/4074; G01N27/416; G01N27/417; H01M2008/147; H01M2300/00; H01M2300/0017; H01M2300/0048; H01M2300/0051; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
201 words
An oxygen sensor apparatus for measuring the oxygen content of a gas mixture comprising oxygen and combustible gases wherein said gas mixture includes carbon dioxide, or the combination of carbon dioxide and water vapor besides oxygen, the apparatus comprising: a molten carbonate electrochemical cell defining a plenum and disposed in use to admit a sample of the mixture of oxygen and combustible gas to be monitored, said plenum comprised of a molten-carbonate-electrolyte wall consisting of a eutectic carbonate mixture impregnated in a porous support and first and second electrodes disposed on and contacting opposite surfaces of said molten-carbonate-electrolyte wall; means for supplying an oxygen/combustibles gas mixture containing carbon dioxide, or a combination of carbon dioxide and water vapor, besides oxygen into said plenum for contact with the first inside surface of said molten carbonate electrolyte wall; means for transporting carbon dioxide and a corresponding amount of oxygen for reaction from said gas mixture through said wall to the outside of said plenum to deplete the oxygen present in said gas mixture, said transport of carbon dioxide and oxygen producing an electrochemical cell current; and means for measuring said cell current as an indication of the oxygen content of said gas mixture.
Claim 2
Dependent Claim
201 words
An oxygen sensor apparatus for measuring the oxygen content of a gas mixture comprising oxygen and combustible gases wherein said gas mixture includes carbon dioxide, or the combination of carbon dioxide and water vapor besides oxygen, the apparatus comprising: a molten carbonate electrochemical cell defining a plenum and disposed in use to admit a sample of the mixture of oxygen and combustible gas to be monitored, said plenum comprised of a molten-carbonate-electrolyte wall consisting of a eutectic carbonate mixture impregnated in a porous support and first and second electrodes disposed on and contacting opposite surfaces of said molten-carbonate-electrolyte wall; means for supplying an oxygen/combustibles gas mixture containing carbon dioxide, or a combination of carbon dioxide and water vapor, besides oxygen into said plenum for contact with the first inside surface of said molten carbonate electrolyte wall; means for transporting carbon dioxide and a corresponding amount of oxygen for reaction from said gas mixture through said wall to the outside of said plenum to deplete the oxygen present in said gas mixture, said transport of carbon dioxide and oxygen producing an electrochemical cell current; and means for measuring said cell current as an indication of the oxygen content of said gas mixture.
Claim 3
Dependent Claim
59 words
A sensor apparatus as claimed in claim 1 further including means for heating said molten carbonate electrochemical cell to a temperature predetermined range to enhance the conductivity of said molten carbonate cell while limiting said temperature to a level less than that at which a combustible reaction would occur between the oxygen and combustibles constituents of said gas mixture.
Claim 4
Dependent Claim
43 words
A sensor apparatus as claimed in claim 1 wherein said eutectic carbonate mixture comprising said molten carbonate electrolyte wall is a mixture selected from the following: Li 2 CO 3 , K 2 CO 3 , Na2C03, and Cs 2 CO 3 .
Claim 5
Dependent Claim
21 words
A sensor apparatus as claimed in claim 1 wherein said porous support is of non-reactive ceramic material consisting of lithium aluminate.
Claim 6
Dependent Claim
16 words
The sensor apparatus as claimed in claim 1 wherein said first electrode is a noncatalytic electrode.
Claim 7
Dependent Claim
28 words
A sensor apparatus as claimed in claim 2 wherein said means for heating maintains said molten carbonate electro-chemical cell wall at a temperature approximately between 400 and 700°C.
Claim 8
Dependent Claim
165 words
A gas sensor apparatus as in claim 1 including a second electrochemical cell means having an electrolyte and third and fourth electrodes disposed on and contacting opposite surfaces thereof, said third electrode being a catalytic electrode, the gas mixture devoid of the oxygen content which was depleted by said molten carbonate electrochemical cell flowing to contact said third electrode of said second electrochemical cell, an external oxygen gas environment being provided to contact said second electrode of said second electrochemical cell, means for transporting oxygen from said external oxygen gas environment to the third electrode surface of said second electrochemical cell, said third electrode being a catalytic electrode causing a combustible reaction between the oxygen and the combustible constituents of said gas mixture the transporting of said oxygen producing a cell current in said second electrochemical cell means, and means for measuring the cell current of said second electrochemical cell to give an indication of the content of combustible gases in the oxygen/combustibles gas mixture.
Claim 9
Dependent Claim
66 words
A gas sensor apparatus as claimed in claim 7 wherein said second electrochemical cell is a molten-carbonate-electrochemical cell, said external oxygen gas environment contacting said fourth electrode including C0 2 , said means for applying a voltage across the electrodes of said second electrochemical cell means transporting C0 2 and a corresponding amount of 0 2 through said molten carbonate electrochemical cell to said third electrode.
Claim 10
Dependent Claim
46 words
A sensor apparatus as claimed in claim 8 wherein said eutectic carbonate mixture comprising said molten carbonate electrolyte is a mixture selected from the following: Li 2 CO 3 , K 2 CO 3 , Na 2 C0 3 , and Cs 2 CO 3 .
Claim 11
Dependent Claim
21 words
A sensor apparatus as claimed in claim 7 wherein said porous support is a non-reactive ceramic unit consisting of lithium aluminate.
Claim 12
Dependent Claim
55 words
A gas sensor apparatus as claimed in claim 7 wherein said second electrochemical cell is an oxygen ion conductive solid electrolyte electrochemical cell, said means for transporting oxygen consisting of a voltage source connected across the electrodes of said second electrochemical cell means to pump oxygen from said oxygen gas environment to said third electrode.
Claim 13
Dependent Claim
44 words
A gas sensor apparatus as claimed in claim 11 further including means for heating said molten carbonate electrochemical cell to a temperature approximately between 400 to 700°C and heating said oxygen ion conductive solid electrolyte cell to a temperature of approximately 800°C or higher.
References Cited (Backward Citations)
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