Knifegate Control Valves

Knifegate with linear pnuematic actuator

A knife gate valve has a metal wedge or gate that "slices" through a process material. The valve is inserted in the piping system directly in the line of flow, or at the discharge end. The valve uses a a linear motion to open and close. In the closed position, the knifegate valve is designed to seat tightly and not allow leakage in either direction. They are designed to minimize pressure drop across the valve when fully open. They are great for slurries and thick, viscous fluids. Knifegate valves are operated via manual hand wheel or with pneumatic or electric actuators.

Although knifegate valves are designed primarily for for on-off service, there are situations and modifications available where they can be used for control (throttling). When used as control valves, the gate is precision machined with a notch or "V" to provide a specific flow characteristic that linearizes the flow through the valve. Without this modification, a standard knifegate disk demonstrates very non-linear flow characteristics and higher disk and seat wear.