According to structure and function, it can be divided into:
1. There are several types of pneumatic ball valves. The floating pneumatic ball valve is used as a sealing element. The ball is floating. It uses the pressure of the medium itself to push the ball to produce displacement of the moving distance, squeezing the elastic valve seat to achieve the sealing effect. This kind of floating pneumatic ball valve has a large resistance to opening, which is only applicable to pipelines and equipment with a diameter of DN 200 and a pressure of PN 100. If the diameter of the ball is too large, the valve body will be bent under the pressure of the medium and become invalid; if the pressure is too large, the compression elasticity of the pneumatic ball valve will cause permanent deformation by using the elastic valve seat, which may damage the seal and affect the service life of the pneumatic ball valve.
2. The fixed pneumatic ball valve is fixed by the upper and lower valve stems. The valve seat is equipped with a plate spring or cylindrical spiral spring. When equipped, the spring of the valve seat is compressed to produce a preload, so as to achieve the initial sealing of the valve. During use, the pressure pushes the valve seat to move onto the ball to achieve sealing. Since the ball does not move, it is called a fixed pneumatic ball valve. Because its sealing reliability is far greater than that of the floating pneumatic ball valve, this kind of fixation has a wider range of applications, which can be applied not only to low pressure small caliber, but also to high pressure large caliber. However, its structure is relatively more complex and its price cost is higher. When selecting it, you should choose it according to the actual needs.
3. Eccentric semi pneumatic ball valve This pneumatic ball valve adopts an eccentric structure. Its structural principle is similar to that of the multi-level three eccentric hard sealing butterfly valve. The valve seat and ball are not worn and have the sealing function of closing more tightly. The ball is only 1/4 of the spherical surface of an ordinary pneumatic ball valve. It is light in weight and relatively inexpensive. This kind of ball valve has a shearing effect and can be used in medium pipelines containing long fibers, No jamming will occur.
4. Thermal insulation pneumatic ball valve The flange of thermal insulation pneumatic ball valve is one to two specifications larger than the general flange pneumatic ball valve. It adopts an integral valve body and a side mounted ball valve design. A metal jacket, also known as jacketed pneumatic ball valve, is welded between the enlarged flanges outside the valve body. Jacket interfaces are installed on both sides of the valve body, which can inject steam or other superheated gases to prevent the medium from solidification or crystallization at normal temperature. Thermal insulation pneumatic ball valve is mainly used in pipelines and devices that are easy to crystallize and need thermal insulation in petroleum, chemical, metallurgical and pharmaceutical systems.
5. V-shaped pneumatic ball valve is a kind of regulating pneumatic ball valve. The flow passage hole of the ball valve is very different from the straight through hole of the ordinary pneumatic ball valve. The ball valve is V-shaped and usually adopts a fixed structure with two upper and lower stems
6. Fluorine lined pneumatic ball valve is commonly used in the pipeline of equipment with low temperature and strong corrosive medium. This pneumatic ball valve is lined with PFA or FEP and other corrosion-resistant engineering plastics at all parts of the flow channel in contact with the medium. It can replace expensive stainless steel, Hastelloy, Monel alloy and No. 20 alloy under the condition that the service temperature of fluororubber is not exceeded in the low-pressure pipeline, solving the transportation problem of strong corrosive media in petrochemical and chemical pipelines

6、 If slight leakage is found at the packing during use, the valve stem nut can be tightened slightly until the leakage stops. Do not continue tightening.