Valve pneumatic actuator overview:
Pneumatic actuators (also known as pneumatic heads), also known as pneumatic actuators or pneumatic devices, are actuators that use compressed air supply pressure to drive opening and closing or adjusting valves. They are mainly composed of cylinders, pistons, gear shafts, and ends. Cover, seals, screws, etc. Pneumatic actuators are generally used with various types of valves, including opening indication, stroke limit, solenoid valve, positioner, pneumatic components, manual mechanism, signal feedback and other components. The opening, closing, opening and closing of the valve are controlled by compressed air.
Working principle of valve pneumatic actuator:
Pneumatic actuators can be divided into single-acting and double-acting according to the form of action. Double-acting actuators are air-opening and air-closing, that is, the ventilation is open and the ventilation is closed. When the air source is lost, there is no action and stay in place. The single-acting actuators have the function of spring reset. Generally, there are normally closed and normally open types, that is, the ventilation is opened. When the air source is lost, it is automatically reset to the initial state. It is used more frequently in dangerous working conditions. It can quickly close or open the valve when a sudden failure occurs due to the loss of gas source.
【Working principle of double-acting pneumatic actuator】
When the pressure of the air source enters the middle cavity between the two pistons of the cylinder from the air port (2), the two pistons are separated and moved to the two ends of the cylinder, and the air in the air chambers at both ends is discharged through the air port (4), and the two piston racks are synchronized Drive the output shaft (gear) to rotate counterclockwise. Conversely, when the pressure of the air source enters the air chambers at both ends of the cylinder from the air port (4), the two pistons move in the middle direction of the cylinder, and the air in the intermediate air chamber is discharged through the air port (2), and simultaneously the two piston racks simultaneously drive the output shaft (gear ) Rotate clockwise. (If the piston is installed in the opposite direction, the output shaft becomes reverse rotation)
【Working principle of single-acting pneumatic actuator (with spring return)
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When the pressure of the air source enters the middle cavity between the two pistons of the cylinder from the air port (2), the two pistons are separated and moved to the two ends of the cylinder, forcing the springs at both ends to compress, and the air in the air chambers at both ends is discharged through the air port (4). The two piston racks synchronously drive the output shaft (gear) to rotate counterclockwise. After the air source pressure is reversed by the solenoid valve, the two pistons of the cylinder move in the middle direction under the elastic force of the spring. The air in the middle air chamber is discharged from the air port (2), and the two piston racks simultaneously drive the output shaft (gear) Rotate clockwise. (If the piston is installed in the opposite direction, the output shaft will turn in reverse when the spring returns)
