Of course, like the positioning scheme of the pneumatic control valve, a positioning valve and a two position three-way solenoid valve can be installed between the positioner and the actuator. When the air is cut off, the positioning valve can be used to maintain the position, and when the signal is cut off, the solenoid valve can be used to maintain the position. However, the solenoid valve and positioner shall be interlocked. 　　　　

Third, when the processing plant uses the pneumatic butterfly valve, it can be fully opened or fully closed. In this way, the key is to avoid the erosion of the sealing surface, which will also accelerate the degree of wear.