GB692712A - Method of and apparatus for testing combustible gas - Google Patents

Abstract

<PICT:0692712/III/1> The approach to explosibility of a combustible gas, due to the presence of oxygen or air therein, is tested by adding to the combustible gas a predetermined proportion of air and leading a sample of the resulting mixture into an explosion chamber, and subjecting the charge when stationary in the explosion chamber to the action of an ignition device. Any resulting explosion may be used to switch off an electrostatic precipitator used in purification of the gas. As shown, pumps 5, 10 operated by a coupled power drive 21 through adjustable eccentrics 18, 19, deliver gas and air respectively via a flame trap 14 to explosion chamber 15 where the mixture is subjected to a spark between electrodes 24. An explosion raises cap 26 and opens switch 31 in the control circuit of the electrostatic precipitator. A flexible diaphragm may replace the cap 26. Pumps giving a continuous flow may be used in place of the pumps 5, 10, in which case intermittent supply to the explosion chamber is effected by a diversion valve operated by timing gear. In an alternative arrangement, Fig. 2 (not shown), a constant sub-atmospheric pressure is maintained on the delivery side of a rotary pump by means of a governor-regulated valve in the gas supply line, and air is admitted through a calibrated orifice plate; two explosion chambers which operate alternately are provided.