Device for the continuous determination of carbon monoxide content of air

Claim 1

An electrochemical cell, for the continuous determination of the carbon monoxide content of a gas, such as air, in the emission and immission ranges, comprising, in combination, a receptacle containing an acid electrolyte; a cathode having a surface in contact with the electrolyte; a diffusion anode, depolarizable by carbon monoxide, having an inner active layer in contact with the electrolyte and a superposed outer hydrophobe gas diffusion layer out of contact with the electrolyte; means subjecting the anode to the carbon monoxide-containing gas by flow of the gas through said diffusion layer; said anode, at a potential of less than 1000 mV relative to a hydrogen electrode in the same electrolyte, being subject to oxygen-reduction; said cathode being constituted by an unpolarizable material, selected from the group consisting of oxides and mixed oxides of the transition metals, having an oxidation potential of over 1000 mV relative to a hydrogen electrode in the same electrolyte; and current measuring means connected, in short circuiting relation, between said cathode and said anode to polarize said anode to the potential of said cathode so that, in the absence of carbon monoxide, no current flows between said cathode and said anode and so that no oxygen-reduction takes place at said anode; whereby said anode, when subjected to a gas containing both oxygen and carbon monoxide, functions only as an anode for the oxidation of the carbon monoxide and is depolarized relative to said cathode to provide a corresponding current flow through said current measuring means; said cell functioning without any external current source.