Solid wedges are one rigid piece; flexible wedges are cut around the rim so they can flex slightly and still seal when the body distorts with heat or pipe load; split wedges are two halves that align themselves to the seats. The wedge shape gives mechanical seating force, which is also why a hot valve closed tight can lock the wedge in place when it cools.
Solid wedge on that steam gate is stuck in the seats, we're going to need heat and a big wrench to break it loose.
Also heard as
- gate
- disc
Related terms
Gate valve
A multi-turn isolation valve that lifts a flat or wedge-shaped gate clear of the flow path to open.
Seat
The surface inside a valve that the closure member presses against to stop flow.
Pressure locking
A closed gate valve that cannot be opened because trapped pressure in its bonnet cavity jams the wedge into both seats.
Disc
The movable closure element that seats to stop flow in globe, check, safety and butterfly valves.