Gas sensing unit for use in environment comprising explosive gases

摘要

A gas sensing unit designed to be protected against explosions and serving for the detection of combustible gases in an atmosphere, containing a gas sensor functioning according to the principle of catalytic oxidation or a semiconductor gas sensor. The gas sensing unit contains, within a housing, at least two mutually separated chambers or spaces. The one chambr is a compression-proof space and contains an electronic evaluation circuit for the gas sensor, the other chamber, which is a space structured to be protected against explosions, contains the gas sensor and a balancing element and is separated from the atmosphere by a sintered metal bushing or sleeve. A third explosion-proof chamber or space can be provided in the gas sensing unit for the purpose of connecting the lines or conductors. The gas sensor together with the balancing adapter forms an assembly or unit which can be pluggably arranged in the cover of the chamber containing the electronic system or hardware. With such type gas sensing unit it is possible to easily exchange the gas sensor at its erection site, without the need for having to open the compression-proof chamber containing the electronic components. The testing and balancing of the gas sensor can be accomplished at the manufacturing plant.