Schematic diagram of air valve principle

Compressed air with pressure P is input from the left end, throttled through the valve port, and the pressure drops to P output. The size of p can be adjusted by the pressure adjusting spring. Turn the knob clockwise, compress the spring and diaphragm to move the spool down, increase the opening of the valve port to increase P, turn the knob counterclockwise, and the opening of the valve port will decrease, and P will decrease accordingly. If P rises instantly, P will also rise, so that the pressure in the diaphragm air chamber will increase and the thrust generated on the diaphragm will also increase accordingly. This thrust will destroy the balance of the original force, make the diaphragm move upward, and a small amount of airflow will be discharged through the overflow hole and the exhaust hole. When the diaphragm moves up, the valve core also moves up due to the action of the return spring, the intake valve is turned down, the throttling effect is increased, and the output pressure is reduced until a new balance is reached, and the output pressure basically returns to the original value. If the input pressure drops instantly, the output pressure also drops, the diaphragm moves down, the valve core moves down, the intake valve opens wider, and the throttling effect decreases, so that the output pressure basically returns to the initial value. Turn the knob counterclockwise. When the adjusting spring is relaxed, the thrust of gas on the diaphragm is greater than the acting force of the pressure adjusting spring, the diaphragm bends upward, and the intake valve is closed under the action of the return spring. When the knob is rotated again, the top end of the intake valve core will be separated from the pressure relief valve seat, and the compressed air in the diaphragm air chamber will be discharged through the pressure relief hole and the exhaust hole, so that the valve is in a state of no output.