Gas detecting and measuring device

Claim 1

A gas .Iadd.device for continuously, quantitatively .Iaddend.detecting and measuring .[.unit.]. .Iadd.a noxious gas in the presence of air .Iaddend. comprising in combination intake means, an electrochemical cell, means for drawing a gas through said intake means and into said electrochemical cell at a controlled flow rate, .[.and read-out means for reading the quantity of said detected gas,.]. said electrochemical cell comprising .Iadd.a housing, .Iaddend.an anode .Iadd.comprising catalyst bonded to a hydrophobic fluorocarbon membrane to provide a diffusion electrode.Iaddend., a cathode, a reference electrode at which substantially no current flows, .Iadd.all positioned within said housing, .Iaddend.and an aqueous electrolyte in an electrolyte chamber, .[.said electrolyte being in contact with.]. .Iadd.each of .Iaddend.said anode, cathode, and reference .[.electrode,.]. .Iadd.electrodes having a catalyst surface containing said electrolyte and said reference electrode contacting air, .Iaddend.means for exposing said anode to a gas to be detected .Iadd.in the presence of air.Iaddend., .Iadd.potentiostat .Iaddend.means .[.for.]. maintaining said anode at a fixed potential relative to the reference electrode of from about 0.7 to 1.5 volts with respect to a reversible hydrogen electrode potential in said electrolyte of said cell, within which range oxygen reduction or oxidation of water to oxygen does not occur, .[.said anode comprising a catalyst bonded to a hydrophobic fluorocarbon to provide a diffusion electrode and.]. said catalyst .Iadd.of said anode catalyst surface .Iaddend.catalyzing an electrochemical reaction with a gas selected from the group consisting of CO, hydrocarbons, alcohols, NO, NO 2 and SO 2 at said fixed potential.Iadd., said anode being arranged in said cell so that one surface of said anode contacts said gas exposing means and the opposite surface contacts said electrolyte whereby the noxious gas to be detected migrates from the surface contacting said exposing means to the internal surface of said anode to interface with the electrolyte for electrochemical reaction in the presence of said catalyst, means for continuously measuring said current flowing between said anode and cathode of said cell, said measured current being a measure of the concentration of the gas being detected, and read-out means for continuously reading said concentration of gas being detected.Iaddend..