Carbon dioxide measurement
AssigneeNational Research Development Corporation
InventorWyndham J. Albery
Life of this patent
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Abstract
Carbon dioxide in the presence of oxygen is sensed by passage of the gas mixture through a layer of polymeric material and through a first, porous, working electrode in contact with a layer of aqueous electrolyte any oxygen being reduced at the electrode; any CO.sub.2 gas passes through the aqueous electrolyte and through a CO.sub.2 -permeable layer of polymeric material to a layer of non-aqueous solvent in contact with a second working electrode at which any CO.sub.2 gas is reduced, causing a current to flow.
Claims6
Apparatus for sensing the presence of carbon dioxide in a fluid which may contain oxygen comprises in series array:
- a first layer of high polymeric material which is permeable to carbon dioxide and oxygen, and which has in contact with one surface a porous layer of metal which constitutes a first working electrode;
- in contact with said first working electrode a layer of an aqueous electrolyte;
- a second layer of high polymeric material which is permeable to carbon dioxide;
- in contact with said second layer a layer of a non-aqueous solvent;
- a second working electrode in contact with the non-aqueous solvent;
- and circuit means arranged to hold the first working electrode at a potential such that oxygen but not carbon dioxide is reduced in the aqueous electrolyte, to hold the second working electrode at a potential such that carbon dioxide is reduced in the non-aqueous solvent, and to sense any current flowing through the second working electrode.
A method of sensing the presence of carbon dioxide in a fluid which may contain oxygen comprises:
- exposing to the fluid a first layer of high polymeric material which is permeable to carbon dioxide and oxygen, and which has in contact with one surface a porous layer of metal which constitutes a first working electrode, the first working electrode being in contact with a layer of an aqueous electrolyte remote from the fluid;
- holding the first working electrode at a potential such that oxygen but not carbon dioxide is reduced in the aqueous electrolyte;
- exposing to the aqueous electrolyte a second layer of a high polymeric material which is permeable to carbon dioxide, the second layer of high polymeric material being in contact with a layer of a non-aqueous solvent remote from the aqueous solvent, and there being a second working electrode in contact with the non-aqueous solvent;
- holding the second working electrode at a potential such that carbon dioxide is reduced in the non-aqueous solvent;
- and sensing any current flowing through the second working electrode.
Dependencies are inferred from the claim text.