IMPROVED AUTOMATIC STOP VALVE

摘要

A stop valve has a piston (12) slidable within a housing (10). Co-operating valve element (20) and seat (14a) regulate fluid flow between inlet port (13) and outlet port (15) in response to movement of piston (12). Piston (12) moves in response to control fluid pressure applied to control port (16). When fully open, piston (12) and second valve element (21) seal the control fluid from the regulated fluid. Dynamic seals are not required between piston (12) and housing (10). The valve is suitable for both normally open and normally closed constructions.