DETECTING APPARATUS FOR CONCENTRATION OF GAS

摘要

PROBLEM TO BE SOLVED: To obtain a detecting apparatus by which the concentration of a gas to be measured can be detected precisely even when the pressure of a gas containing the gas to be measured is changed. SOLUTION: A detecting apparatus is provided with a housing 3 installed so as to be branched from a main flow passage 1 through which a gas containing a gas to be measured is passed and with a gas-concentration detecting sensor (an oxygen sensor) 2 which is arranged inside a chamber 31 at the housing 3. Vent holes 32, 33 through which the gas is made to flow out to the side of the air A through the chamber 31 from the side of the main flow passage 1 and by which a pressure inside the chamber 31 is made nearly equal to atmospheric pressure are made in the housing 3.