Working principle of pneumatic butterfly valve double acting and single acting butterfly valves
date:2026-03-27 10:58
The operating principle of a double acting pneumatic butterfly valve is to have two air chambers on the left and right sides. The pneumatic butterfly valve inputs the air source signal pressure output by the double acting locator into the left and right air chambers of the actuator piston. Due to the different air source pressures on both sides of the input chamber, a pressure difference is formed between the two chambers, which drives the piston to move in a straight line. Through gear and rack transmission, the linear motion of the piston is converted into the rotational motion of the actuator spindle. When the pressure in the left and right chambers is balanced, the motion stops. If it is necessary to adjust the flow rate, it is necessary to drive the valve stem and valve core to rotate while the actuator rotates, in order to change the flow area between the valve core and valve seat and achieve the purpose of adjustment.
The operating principle of single acting pneumatic butterfly valve:
The gas signal pressure output from the single acting locator of the single acting butterfly valve is input into the chamber on the springless side of the pneumatic actuator. Due to the difference between the thrust and spring force caused by the gas signal pressure on the piston, the cylinder piston will move in a straight line. When the thrust generated by the gas signal pressure is balanced with the spring force through gear and rack transmission, the motion stops. And, while the main shaft of the actuator rotates, it drives the valve stem and valve core to rotate, thereby changing the flow area between the valve core and valve seat, achieving the purpose of regulation.
