Gate valve with rapid closure action - has pneumatic pressure biased piston actuator held back by releasable latch

摘要

The gate valve has a closure member movable into the closed position by a pneumatic actuator having a piston (7) connected to the closure member. This is normally held in the open position by a latch (16) while the piston is subject to pressure in the sense to open the valve. Opening of the valve is effected by release of the lath so that the valve closes rapidly under pressure on the piston. The latch may act on a rod (12) secured to the piston and passing through the end of the cylinder remote from the closure member.