Compress the pre tensioned spring to make the valve seat separate from the spherical surface to form a relief channel, so as to ensure that the pressure in the middle chamber can be smoothly discharged into the pipeline, avoiding the potential safety hazard caused by the abnormal pressure rise in the middle chamber. The self discharging valve seat can be used for media in any state, without abnormal pressure rise caused by chemical change or phase change of unstable media in the valve chamber. Because only one valve seat plays a sealing role during normal operation, the operating torque of the valve is relatively low. This structure has mature technology and simple manufacturing. Since only the upstream valve seat plays a sealing role for the self draining valve seat, the sealing performance of the valve will be affected when the upstream valve seat is damaged. At this time, the installation direction of the valve must be turned 180 degrees before continuing to use.

How to determine the length of pneumatic butterfly valve?
The length is very important. We often do not do this work well when we confirm the length of the pneumatic butterfly valve, so that the pneumatic butterfly valve in working condition often has problems of one kind or another due to the improper length. For example, if the pneumatic butterfly valve used in the pipeline system is too long, it will produce greater fluid resistance, etc. Therefore, it is very important to confirm the length of the pneumatic butterfly valve. Next, we will introduce the methods for determining the length of pneumatic butterfly valves in several different application places.
1. The length of gooseneck used as compensator depends on the size of drift diameter. In the pipeline system, if the compensation amount of one compensator is not enough, two or three compensators can be used. If it is restricted by the space location conditions, it is impossible to install a large number of compensators, and the compound structure can be selected.
2. The length of the pump inlet and pump outlet receiving for vibration and noise elimination depends on the size of its diameter, that is, if the diameter is less than or equal to 100mm, L is the length of the flexible section of the compensator or pneumatic butterfly valve; Is the diameter of compensator or pneumatic butterfly valve.
3. Angular displacement, the length depends on the size of its practical bending radius and displacement angle. The length of the pneumatic butterfly valve with horizontal displacement depends on its practical bending radius and horizontal displacement. The tangent section refers to the intermediate transition section of two pipes with the same radius and in different directions when the pneumatic butterfly valve moves laterally.