What is the working principle of stainless steel pneumatic angle seat valve?

Combined with this drawing, air is generally controlled by solenoid valve, pneumatic control valve or manual control to enter the air inlet as shown in the figure.

During air supply, compressed air enters the pneumatic control head to push the piston (the green part is a small piston) to move upward against the elastic force of the return spring. At the same time, the piston drives the valve stem and the valve body, and finally the sealing disc is opened and the valve is in an open state.

When there is no air supply, the return spring presses the sealing disc on it and the valve is closed.

You can see from the indicator whether the valve is closed or open. Generally speaking, when the red pointer comes out, the valve is open, otherwise, it is closed.