METHOD AND APPARATUS FOR COMBUSTIBLE GAS DETECTION IN DIRT LADEN ATMOSPHERE

摘要

A diffusion type head for detection of combustible gas is placed within an enclosure. At least part of the wall forming the enclosure is of an air filtering material. A conduit communicating with the interior of the enclosure has a vacuum applied thereto so that a draft of air exterior of the enclosure is drawn through the filter and about the diffusion type detector. Periodically the vacuum is shut off and a blast of gas under pressure is applied to the conduit to create a reverse flow through the filter and clean out the filter.