(1) During the development of ferrule connection in recent years in China, the principle of selecting the "ferrule connection" mode is that when the nut is tightened, the ferrule will be under pressure, causing the edge to bite into the outer wall of the pipe. The conical surface of the ferrule will be connected with the inner conical surface of the joint under pressure, thus preventing leakage. The reason why this pneumatic butterfly valve is adopted is mainly because of its strong connection force, wide application range and high pressure resistance. 　　

Pneumatic ball valve is a ball valve equipped with a pneumatic actuator to drive the opening and closing of the ball valve through the pneumatic actuator. Because the pneumatic actuator is relatively fast in implementation, and the fast opening and closing speed is 0.05 seconds/time, it is also commonly called pneumatic quick stop ball valve. Generally, pneumatic ball valves are not used alone. They are usually equipped with various accessories, such as solenoid valves, air source processing triplets, limit switches, positioners, control boxes, etc., which are intended for local control and remote centralized control. The valve can be opened and closed in the control room without the need to go to the site or to the high altitude and dangerous areas for manual control, It saves human resources, time and security to a large extent.