Pressure-sealed gate valve - has stepped seal ring engageable with gate in inlet side and released by changing pressure application region

摘要

A gate valve has a spindle operated valve plate (8) that moves across the flow path (4) in order to open and close the valve. A seal ring (32) which has the form of a stepped piston can be pressed against the valve plate (8) on the medium inlet side of the valve. The contact face of the real ring (38) seals the valve plate location when the medium pressure is applied to the opposite side of the seal ring piston. In order to move the valve plate the medium pressure is applied to the stepped flange (60) on the piston (32) so that the clamping force on the valve plate is removed.