Decompressor for water hydrant - comprises valve in each outlet plug which is automatically depressed on removal

摘要

The automatic decompressor for a water hydrant is contained in each outlet plug (2) and comprises a valve (7), one end (7a) of which is normally held against a seat (6a) by the internal pressure and the other end (8) of which passes through a hole (6b) to the exterior of the hydrant. When a shaped spanner (5) is used to remove the outlet plug, it depresses the outer end of the valve releasing compressed air which may have built up in the hydrant.