Gate valves (also called knife valves) are mostly used in large diameter pipelines. They have a flat gate (closure element) which travels perpendicularly to the flow axis. The gate valves act as shut-off valves and basically should not be used in any other way, especially to control the flow, because of the cavitation effect and high obstruction in the product flow in a semi-closed position.
The gate valves are made of brass or stainless steel. The gate opens by turning the stem (spindle) in the nut using a knob, by turning a lever – lever gate valve, or shifting the piston of an actuator (pneumatic, hydraulic) – piston gate valve. Lever and piston gate valves allow quick flow opening and closing. Industrial gate valves are available in diameters up to DN200 (8″) and larger.
They are used in all kinds of industrial systems, in the chemical and oil industry, water supply networks, agriculture, transport and sewage disposal. Working pressure from a couple up to several tens of bar.