DETECTOR FOR MEASURING THE FREE OXYGEN CONTENT IN A COMBUSTIBLE OR HAZARDOUS ATMOSPHERE

摘要

A detector for measuring free oxygen at ambient temperature in a combustible atmosphere (14) which may be hazardous comprises a differential thermocouple pair (24) having a first thermocouple junction coated with a catalyst and a second thermocouple junction coated with a non-catalyst. Free oxygen in the combustible atmosphere reacts with the catalyst to liberate heat and thereby raise the temperature of the catalyst coated junction above that of the non-catalyst coated junction. Thus, the increase in temperature of the first thermocouple above that of the second thermocouple is indicative of the free oxygen in the combustible atmosphere.