A reverse flush gas valve

摘要

A gas valve which has provision for a reverse flow pulse of high pressure gas. The valve includes a reservoir (53) which is loaded with high pressure gas during normal operation which is released into the main flow path by an applied pressure reduction. The valve is fitted to a porous ceramic "candle" filter (1) between dirty (D) and clean (C) gas zones. The high pressure gas pulse reverses flow through the filter (1) and blows off any aggregated dirt. A shut-off valve (43) is arranged to shut the valve in the event the ceramic filter (1) breaks. The valve is efficient and uses only a metered amount of high pressure gas with little loss of pressure between supply and flushing.