What is the working principle of pneumatic valve?

Working principle of pneumatic actuator

When compressed air enters the pneumatic actuator from the nozzle A, the gas pushes the double pistons to move linearly to both ends (cylinder head end), and the rack on the piston drives the gear on the rotating shaft to rotate 90 degrees counterclockwise, and the valve is opened. At this time, the gas at both ends of the pneumatic actuator valve is discharged with the B nozzle. On the contrary, when compressed air enters both ends of the pneumatic actuator from the B nozzle, the gas pushes the double plug to move linearly in the middle, and the rack on the piston drives the gear on the rotating shaft to rotate 90 degrees clockwise, and the valve is closed. At this point, the gas in the middle of pneumatic actuators is discharged through nozzle A ... This is the standard transmission principle. According to the user's requirements, the pneumatic actuator can be installed with the transmission principle opposite to the standard one, that is, rotating the valve clockwise and closing the valve counterclockwise. Single-acting (spring-return) pneumatic actuator, nozzle A is the air inlet and nozzle B is the air outlet (nozzle B should be equipped with muffler). The inlet of the nozzle opens the valve, and when it exhales, the valve is closed by spring force.

pneumatic valve