Patent ID: 6044689
Filing Date: 2000-04-04
Classification: G01N,Y02A,Y10T

Abstract:
A chamber used for an apparatus for sensing low concentration NOx in a measurement gas having, a catalyst arranged to maintain partial pressures of NO and NO.sub.2 in the measurement gas at an equilibrium state, and first and second sensor elements arranged in a flow path of the measurement gas, the resistance of each of said first and second sensor elements varying in response to changes in NOx concentration of the measurement gas, said first sensor element being contacted with the measurement gas which is not contacted with said catalyst and said second sensor element being contacted with the measurement gas which is contacted with said catalyst, comprising:a chamber main body having a gas inlet and a gas outlet of the measurement gas;a first sensor element securing portion for securing said first sensor element, arranged in said chamber main body;a catalyst accommodating portion for accommodating said catalyst, arranged in said chamber main body;a second sensor element securing portion for securing said second sensor element, arranged in said chamber main body; andfirst, second, third and fourth through holes arranged in said chamber main body in such a manner that said first through hole communicates said gas inlet and said first sensor element securing portion, said second through hole communicates said first sensor element securing portion and said catalyst accommodating portion, said third through hole communicates said catalyst accommodating portion and said second sensor element securing portion, and said fourth through hole communicates said second sensor element securing portion and said gas outlet.