Effect of gas explosion on methane detector output signals

Abstract

Methane concentration monitoring is one of the major centralized monitoring items in Japanese coal mines. Each colliery has many methane monitoring points at which the output signals are recorded on charts. Methane detectors usually provide valuable information on concentration, but if a gas explosion occurs unexpectedly, they could also give more information about the circumstances around the detector or scale of the explosion.

We conducted a gas explosion experiment in a test gallery to collect data on methane detector output signals. The result shows that each of the various types of detector, with their different detecting methods, have unique fluctuations of output caused by the explosion. Interferometer type and thermal conductivity type detectors indicated the atmospheric pressure change that was caused by the explosion pressure. After the indication of explosion pressure, each detector sent its corresponding response to the afterdamp. The effect of heat generated by the explosion is considered to be negligable in this experiment.