What are gate valves?

Gate valves were once the most widely used valves in industrial piping systems, however their popularity has now been replaced by ball valves. Gate valves are also used as stop valves - to fully turn off or fully turn on flow - the only application for which gate valves are recommended.

Seating is perpendicular or at right angles to the direction of flow, making gate valves impractical for throttling applications and for frequent operation.

Repeated movement of the wedge (gate) near the point of closure under high velocity flow, may create a drag on the seating surfaces and causing galling or scoring on the down stream side. A slightly opened edge may cause turbulent flow with vibration and chattering of the wedge.

A gate valve requires more turns and therefore more turns to open and close it fully. Also, unlike many globe valves, the volume of flow through the valve is not in direct relation to the number of turns of the handwheel.

Knife gate valves should be used for slurries, fibres, powders etc.

Gate valves are most suited to services requiring full flow or no flow and infrequent operation.