Pneumatic ball valve is evolved from plug valve. It has the same action of rotating 90 degrees, except that the cock body is a sphere with a circular through hole or channel through its axis. The ratio of the spherical surface to the channel opening should be such that when the ball rotates 90 degrees, all spherical surfaces should be present at the inlet and outlet, thereby truncating the flow. This type of valve can be installed anywhere in the pipeline. After explaining the concept, let Zhejiang Shuangzhong Automatic Control Valve Co., Ltd. talk about the working principle and some advantages of pneumatic ball valve.
The pneumatic ball valve only needs to use the pneumatic actuator to drive the valve body to rotate 90 degrees to realize the function of cutting off and opening the flow of the medium. And it only needs a small turning torque to close tightly. The completely equal body cavity of the valve body provides a low resistance and straight flow path for the medium. It is generally considered that the ball valve is most suitable for direct opening and closing, but recent developments have designed the ball valve so that it can be used for throttling and flow control. The main features of the ball valve are its compact structure, easy operation and maintenance, suitable for general working media such as water, solvent, acid and natural gas, and also suitable for media with harsh working conditions, such as oxygen, hydrogen peroxide, methane and ethylene. The ball valve body can be integral or combined.
In the pipeline, it is mainly used to cut off fast, distribute and change the flow direction of the medium. It is a new type of valve that has been widely used in recent years. It has the following advantages:
1. The fluid resistance is small, and its resistance coefficient is equal to the pipe section of the same length.
2. Simple structure, small size, and lightweight.
3. Tight and reliable. At present, the sealing surface material of ball valves is widely used plastic, which has good sealing performance and has also been widely used in vacuum systems.
4. Easy to operate, open and close quickly, just rotate 90° from fully open to fully closed, which is convenient for long-distance control.
5. The maintenance is convenient, the structure is simple, the sealing ring is generally movable, and the disassembly and replacement are more convenient.
6. When fully open or fully closed, the sealing surfaces of the ball and the valve seat are isolated from the medium, and when the medium passes through, it will not cause erosion of the valve sealing surface.
7. Wide range of applications, diameters ranging from small to several millimeters, large to several meters, and can be applied from high vacuum to high pressure.
8. Because the power source is gas, the pressure is generally 0.2-0.8MPa, which is relatively safe. If there is air leakage, compared with hydraulic and electric, the gas can be discharged directly, which does not pollute the environment, and has high safety at the same time.
9. Compared with manual and turbo-rotating ball valves, it can be configured with large diameters (manual and turbo-rotating ball valves are generally below DN300 caliber, and can currently reach DN1200 caliber.)
It has been widely used in petroleum, chemical industry, power generation, papermaking, atomic energy, aviation, rocket and other departments, as well as people's daily life.
