Gas Detector
Gas Detector : Used for the detection of flammable gases or vapours. Several kinds: a) catalytic detectors - these work by measuring the increase in the resistance of an electrical conductor when heat is evolved by oxidation of a flammable gas on the surface of a catalyst. The catalyst can become poisoned; b) non-dispersive infrared (NDIR) detectors - IR radiation passed through a cell containing the gas to be observed will be absorbed differently from radiation in a cell containing a standard gas; c) semi-conductor detectors - molecules adsorbed on to the semiconductor cause an electric charge transfer between its surface and the adsorbed molecules. The charge transfer results in modified conductivity which is measured by the variation in voltage across a load resistance. Exposure to flammable gases produces increased conductivity
No records Found