Pressure Seal Gate Valves
DSI® offers a broad range of Cast Steel Pressure Seal Gate valves in Buttweld and Flanged end connections.
- Size Range: 2" thru 24"
- Pressure Class: 600-4500
- Style: Flexible Wedge and Parallel Slide design
- Materials: A216 WCB, WC6, WC9, C5, C12, C12A, CF8M and special alloys
Standard Construction Features
Flexible Wedge Sealing Design
The flexible wedge is a one-piece, fully guided cast wedge with a central hub to allow the seating faces to move relative to each other, thus compensating for distortion of the body seats due to thermal expansion or piping loads. Seat ring and wedge seating face are set at a 9° angle from vertical to minimize sliding contact of the wedge and seat ring during opening and closing.
Wedging actions help effect a tight seal in low differential pressure services. Flexible wedge construction resists wedge sticking or binding in services where the valve may be closed when cold and opened when hot. Seating surfaces are hardfaced with Stellite®6 to provide high life cycle capability in very high differential pressure services.
Parallel Slide Design
The gate is a split design using two discs spring loaded and held together by a gate holder with a corrosion reservior spring to provide initial energizing when closed. The gate relies for seat tightness on the primary fluid pressure acting on the downstream seat. There is no wedging action or extra loading on the seats resulting in considerably lower operating torque. During closing there is a bevel on the bottom of the gate to guide it in between the seats and recompress the spring. Seating surfaces are hardfaced with Stellite®6 to provide high cycle capability in very high differential pressure services.