China butterfly valve working principle

China butterfly valve is composed of pneumatic actuator and butterfly valve. Due to its characteristics, such as light weight, simple structure and easy operation, the butterfly valve is often installed on large-diameter low-pressure pipelines. Pneumatic butterfly valves are classified according to the butterfly valve sealing form. They can be divided into pneumatic soft sealing butterfly valves, pneumatic hard sealing butterfly valves, pneumatic self-sealing butterfly valves, etc. According to the classification of pneumatic actuators, they can be divided into double acting pneumatic butterfly valves and single acting pneumatic butterfly valves. This paper mainly introduces the working principle of double-acting pneumatic butterfly valve and single-acting pneumatic butterfly valve.

China butterfly valve - double acting pneumatic butterfly valve works:

The double-acting butterfly valve has two left and right air chambers, and the air source signal pressure outputted by the double-acting positioner of the pneumatic butterfly valve is respectively input into the left and right air chambers of the actuator piston. Due to the different pressures of the air supply to the air chambers on both sides, a pressure difference is formed between the two air chambers, thereby pushing the piston to move linearly. Through the gear and rack drive, the linear motion of the piston is converted into the rotary motion of the spindle of the actuator. When the pressure of the left and right air chambers is balanced, the motion stops. If it is necessary to adjust the flow rate, it is necessary to rotate the valve stem and the valve core while the actuator rotates to change the flow area between the valve core and the valve seat to achieve the adjustment purpose.

China butterfly valve - single acting pneumatic butterfly valve works:

The air signal pressure outputted by the single-acting positioner of the single-acting butterfly valve is input into the air chamber of the pneumatic actuator without the spring side. Since the pressure of the gas signal on the piston acts on the difference between the thrust and the spring force, the cylinder The piston will do a linear motion. The gear and the rack drive balance the thrust generated by the pressure of the air signal with the spring force, and the motion stops.Moreover, while the spindle of the actuator rotates, the valve stem and the valve core are rotated, thereby changing the flow area between the valve core and the valve seat, thereby achieving the purpose of adjustment.