A New Type of Thermal Conductivity Gas Detector, I

Abstract

A new type of gas detector with two thermisters and two thermister-cells was designed. Two thermisters were enclosed in each thermister-cells respectively, one of the cells having a porous window through which gases may run into the cell from the outside. Measuring the thermal conductivity of gas permeating into the cell through the porous window, we can detect the gas with high sensitivity. Since the cell is small, the time response is quick, and the sensitivity is increased because of the self-heating effect of the thermister. Using this method, we have been able to detect 0.01% hydrogen contained in air.