Patent ID: 6325906
Filing Date: 2001-12-04
Classification: G01N

Abstract:
A gas sensor comprising:a first processing chamber and a first gas passage for introducing a gas under measurement into said first processing chamber;a second processing chamber and a second gas passage for introducing the gas from said first processing chamber into said second processing chamber, said second processing chamber being provided for the reaction therein of combustible gas components contained in the gas witha third gas passage for introducing a gas containing O.sub.2 into said second processing chamber under diffusion resistance in a predetermined amount in excess of that needed to react with combustible gas components present in the second processing chamber;an oxygen-concentration sensor for sensing the oxygen concentration of the gas introduced from said first processing chamber to said second processing chamber;a first oxygen pump comprising a first inner electrode and a first outer electrode formed on an oxygen-ion conductor in such a manner as to face the interior and exterior, respectively, of said first processing chamber, said first oxygen pump decomposing O.sub.2 into oxygen ions through application of voltage between the first inner electrode and the first outer electrode on the basis of an oxygen-concentration output from said oxygen-concentration sensor and pumping out the generated oxygen ions from or pumping into said first processing chamber through the oxygen-ion conductor to thereby control the oxygen concentration of the gas introduced from said first processing chamber to said second processing chamber;means for accelerating the reaction of O.sub.2 and combustible gas components contained in the gas introduced into said second processing chamber; anda second oxygen pump comprising a second inner electrode and a second outer electrode formed on an oxygen-ion conductor in such a manner as to face the interior and exterior, respectively, of said second processing chamber, said second oxygen pump decomposing into oxygen ions O.sub.2 which remains unconsumed in reaction with combustible gas components in said second processing chamber, through application of a constant voltage between the second inner electrode and the second outer electrode and pumping out the generated oxygen ions from said second processing chamber through the oxygen-ion conductor.