The pneumatic ball valve is installed between the upper and lower valve stems. When the ball is closed, the valve seat spring pushes the valve seat to compress the ball, and the force on the spherical area formed by the outer diameter of the valve seat sealing surface and the spherical sealing line seals the pneumatic ball valve. The reliability of sealing depends to a large extent on the ratio of pMP to Dm. If the ratio of the sealing surface and the contact surface area with the spherical surface is not large enough, the pneumatic ball valve will not be able to ensure reliable sealing, otherwise it will cause overload of the valve seat and seal ring, which will increase the opening and closing torque of the valve and accelerate the wear and tear.

Pneumatic O-ring ball valve structure:
A ball with a middle through hole is installed inside the valve body, and a through hole with a diameter equal to the pipe diameter is opened on the ball. The ball can rotate in the seal seat, and there is a ring elastomer on both sides of the pipe direction to achieve sealing. By rotating the ball 90 °, the direction of the through hole can be changed, thus realizing the opening and closing of the ball valve. The valve core (ball) is spherical. From the structural point of view, the ball valve seat is embedded on the valve body side valve seat when sealing. The relative moving parts are all made of self-lubricating materials with very small friction coefficient, so the operating torque is small. In addition, the long-term sealing of sealing grease makes the operation more flexible. It is generally used for two position regulation, and the flow characteristic is quick opening.