The pneumatic ball valve is evolved from the plug valve. The main difference between them is that while the plug valve rotates 90 degrees, the plug body of the ball valve is a sphere with a circular passage or flow channel passing through its axis. Its working principle is to open or close the valve by rotating the valve core. 

The pneumatic ball valve is lightweight and compact in size. It can be made in large diameters, has reliable sealing, a simple structure, and is easy to maintain. The sealing surface and the spherical surface are often in a closed state, and are not easily corroded by the medium. It has been widely used in various industries. 

Pneumatic ball valves and rotary disc valves are of the same type. Only the closing part is a ball, and the ball rotates around the center line of the valve body to open and close the valve. 

Pneumatic ball valves are mainly used for controlling the flow of fluids in pipelines, regulating cutting speed, distributing fluids, and changing the direction of fluid flow. 

Advantages of pneumatic ball valves: 

1. The fluid resistance is small, and the resistance coefficient is equal to that of the same pipe section length. 

2. Simple structure, small size, and light weight. 

3. The sealing surface materials of ball valves are widely used in plastic products and possess excellent sealing performance. They are also widely applied in vacuum systems. 

4. This utility model is easy to operate and has a fast opening and closing speed. It only needs to rotate 90 degrees from fully open to fully closed, and it is also convenient for remote control. 

5. Easy to maintain. The pneumatic ball valve has a simple structure and the sealing ring can be moved, making it convenient for disassembly and replacement. 

6. When the steel ball and the valve seat are fully opened or closed, the sealing surfaces of the steel ball and the valve seat are isolated from the medium. When the medium passes through, the sealing surfaces of the valve will not be worn. 

7. It has a wide range of applications, with paths ranging from a few millimeters to several meters. It can be used from high vacuum to high pressure. 

8. The power source of the pneumatic ball valve is gas, typically with a pressure ranging from 0.2 to 0.8 MPa. This is relatively safe. In case of leakage in the pneumatic ball valve, compared to hydraulic or electric valves, the gas can be directly discharged, causing no pollution to the environment and offering higher safety. 

9. Compared with manual and turbine ball valves, pneumatic ball valves can be configured with larger diameters (manual and turbine ball valves typically have a diameter of less than DN300, while pneumatic ball valves can now reach a diameter of DN1200). 

Pneumatic ball valves are widely used in various industries such as petroleum, chemical engineering, power generation, papermaking, atomic energy, rocket technology, as well as in people's daily life.