Seal for stop valve with spherical plug - has endless hose forming seal for O-ring piston pressure chamber and having port connection to high pressure chamber

摘要

The seal is for a stop valve with ball-shaped plug, pressed by an O-ring piston concentric to the flow axis of the plug. The piston is actuated in a chamber by hydraulic pressure, derived from the medium and amplified by a differential piston, and is adjustable to ambient pressure by a three-way cock. The pressure chamber of the piston (5) has a leakproof seal, formed by an endless hose (15) bearing against the walls of the housing (2), and which is connected directly or by a bore (20) to the high-pressure chamber (8) of the differential piston (6). This bore and the high-pressure chamber are lined by an endless elastic sheet (21) forming a seal on all sides and a seamless joint to the hose.