Three=way valve with complete shut=off between positions - has double seating action with seats above and below pistons separated by spring loaded bellows

摘要

Valve for gaseous or liquid media has two valve seats with two pistons but with a single actuator. This allows three operating position, with either valve open or both closed. Actuation can be manual or by motor. The closed position is intermediate between the two others. The two pistons are separated by spring loaded belows and are operated from a single actuator with only vertical motion. The valve has a body with three flanged connections. It has two seatings. The lower seating has a threaded insert with a conical seating and flexible seal e.g. PTEE in the centre. A conical plunger fits into this and controls the flow.