Advantages of flange pneumatic ball valve:
(1) The fluid resistance is small, and its resistance coefficient is equal to that of pipe sections with the same length;
(2) Simple structure, small volume and light weight;
(3) Tight and reliable. At present, the sealing surface material of the flange pneumatic ball valve is widely used in plastic, with good sealing performance, and has also been widely used in the vacuum system;
(4) It is easy to operate and can be opened and closed quickly. It only needs to rotate 90 ° from full opening to full closing, which is convenient for remote control;
(5) Convenient maintenance, simple structure of flange pneumatic ball valve, generally movable sealing ring, easy removal and replacement;
(6) When the valve is fully opened or closed, the sealing surfaces of the ball and valve seat are isolated from the medium. When the medium passes through, it will not cause erosion of the sealing surface of the flange pneumatic ball valve;
(7) It has a wide range of applications, ranging from a few millimeters to several meters in diameter, from high vacuum to high pressure.

Method 2: change the flow direction and place P2 at the valve rod end; When △ P is large and P1 is large, sealing P1 is obviously more difficult than sealing P2. Therefore, pneumatic control valves can adopt the method of changing the flow direction, changing P1 at the valve stem end to P2 at the valve stem end, which is more effective for valves with high pressure and large pressure difference. For example, bellows valves should generally consider sealing P2.