(3) In Figure 1, the bottom connecting pipe which plays the role of drainage is connected with the plug by thread. When the temperature rises, it is difficult to ensure the sealing of the threaded part, so it is decided to cancel the plug. In Figure 2, the plug connected with the bottom connecting pipe is replaced with a bench drain plug, and the connecting end is sealed with a winding gasket to ensure the sealing reliability of the bottom end.

1、 The structure of the pneumatic ball valve The pneumatic ball valve is evolved from the plug valve. As a ball, its opening and closing parts use the ball to rotate 90 degrees around the axis of the valve stem to open and close.