Pneumatic valve is a kind of valve. There will be some problems in the process of use, including the pneumatic valve is not closed tightly, what is the reason for the pneumatic valve not closed tightly? How to solve this problem?

1. Incorrect selection of control valve: Different types of custom brass fitting  control valves allow different pressure differences. Sleeve control valves and double-seat control valves allow larger pressure differences than single-seat control valves. Angular stroke V-shaped control ball valves and eccentric rotary valves The allowable differential pressure will be larger. In the case of relatively large pressure difference, reasonable selection is very important.

2. There are impurities inside the regulating valve, and foreign objects cause jamming: it is necessary to disassemble the valve cover of the regulating valve, take out the valve core, and clean it. If the sealing surface is damaged, it must be reground and assembled. The inlet of the regulating valve is preferably equipped with a filter, which can reduce the occurrence of similar situations.

3. Insufficient output force of the pneumatic actuator: As the power part of the pneumatic actuator to drive the action of the valve core of the regulating valve, its output force must be greater than the force required when the valve is closed, otherwise it will not be closed tightly, and the valve core will be pushed open by the medium pressure , resulting in inteal leakage. Therefore, it is necessary to verify the differential pressure value of the process pipeline when selecting the model to ensure that the pneumatic actuator has sufficient output force to close the valve.

4. Valve core damage caused by cavitation flashing: Weld the valve core and valve seat with STL hard alloy, and choose a cavitation-resistant flashing control valve reasonably to reduce its occurrence.

5. The spring stiffness of the diaphragm actuator of the air-opening control valve is not enough: the air-opening diaphragm control valve relies on the spring force to close the valve. The driving force required for opening is small, and the force required for closing is larger. The pressure difference between the front and rear of the valve, when the force of the spring is not enough to overcome the pressure difference force, will cause the situation of loose closing, which needs to be solved by replacing the spring with high stiffness.

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