Working principle of pneumatic butterfly valve

Working principle of pneumatic butterfly valve

The working principle of pneumatic butterfly valves mainly relies on compressed air as the power source, which is controlled by pneumatic actuators (such as cylinders, membrane actuators, etc.) to open and close the valve, thereby regulating the flow rate and direction of the medium. Specifically:

Double acting pneumatic butterfly valve: It has two chambers. When the air source signal pressure output by the double acting locator is input to the left and right chambers of the actuator piston, due to the different air source pressures in the two chambers, a pressure difference will be formed between the two chambers, pushing the piston to move in a straight line. This linear motion is converted into the rotational motion of the actuator spindle through gear and rack and pinion transmission. When the pressure in the left and right chambers is balanced, the movement stops. If it is necessary to adjust the flow rate, the main shaft of the actuator will drive the valve stem and valve core to rotate, changing the flow area between the valve core and valve seat to achieve the purpose of adjustment.

Single acting pneumatic butterfly valve: It has an air chamber, and the air signal pressure output by the single acting locator is input into the air chamber on the spring free side of the actuator. When there is a difference between the pressure effect of the gas signal on the piston and the spring force, the cylinder piston will move in a straight line. Through gear and rack transmission, the thrust formed by the pneumatic signal pressure is balanced with the spring force, and the movement stops. 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 and achieving the purpose of regulating flow.

Control mode: There are two control modes for pneumatic butterfly valves, dual control and single control. The dual control pneumatic butterfly valve is controlled by two pneumatic actuators, which are respectively connected to the air source and exhaust port. A single control pneumatic butterfly valve only has one pneumatic actuator, and its control method is similar to dual control, but only needs to be connected to the air source channel.

By adjusting the pressure and flow rate of the air source, the opening of the butterfly valve can be precisely controlled, achieving the functions of opening, adjusting, and cutting off the fluid.