Switch valves are composed of pneumatic actuators or switching electric actuators with different kinds of valves. They are mainly used in various situations requiring shut-off. Common types of on-off valves include switch ball valves, switch butterfly valves, single seat on-off valves, sleeve on-off valves, three-way on-off valves, etc. Switch valves are mainly used to cut off or connect the medium flow in the pipeline. Accept the signal from the regulator, cut off, open or change the flow direction of the medium, to achieve automatic control of pressure, flow, liquid level and other process parameters. Switch valves are widely used in automatic control and engineering control systems of various industrial sectors, such as petroleum, chemical, metallurgical, electric power, light industry, textile and so on.