Valve for high speed fluid flow - has hard-wearing steel ring fitting over piston to form seal

摘要

The valve is for fluid flowing at high speed, having a housing to which feed and discharge pipes are coupled, the latter via a flange. In the housing at the connection to the discharge pipe is annular valve seat of hard-wearing steel with a cone face, also a fixed guide bush shut at the inlet end and open towards the seat and accommodating a sealing piston moved towards the seat by an external actuator. An annular seal on the piston bears against the seat. The seal is a cylindrical ring (10) of hard-wearing steel fitted over the piston periphery (7), and with a cone face (10a) working against the seat (5). It is secured to the piston by a mushroom-headed screw (11) screwing into the piston end face towards the seat, it head diameter being greater than the internal diameter of the ring, and engaging in a recess (10b) inside the latter. A pressure equalisation chamber (12) is formed inside the bush on the side of the piston furthest from the seat and connected to the interior of the housing via a passage (13) through the piston and screw head.