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Common Fault Judgment and Treatment Method of Pneumatic Ball Valve

Aug. 18, 2020

Aerodynamic ball valves are powered by compressed air, so air leaks often occur during the use of pneumatic ball valves. Let ’s take a look at the ways of air leakage of pneumatic ball valve.
First, check the air source processing device, check whether the filter, pressure reducing valve, oil mister is normal, and observe whether the pressure is 3-8kg;
The signal line of the pneumatic ball valve consists of a pair of control signal lines and a pair of feedback signal lines. When the PLC gives a signal to the valve, the signal is converted in the positioner of the regulating valve, and the valve stem is controlled by the air pressure. The stroke of the valve stem transmits the valve opening degree through the feedback signal of the regulating valve.
If the pneumatic valve does not have a feedback signal, it may be due to a problem in the circuit. Check the signal line connected to the power with a multimeter. For example, check whether there is voltage at each contact, whether the line connection is correct, whether the signal line is damaged, whether the signal line is loose, etc.

Aerodynamic Ball Valve


Aerodynamic Ball Valve

Second, observe whether the pneumatic actuator is leaking, especially the valve stem connection and the two end covers;
1.Air leakage from the cylinder exhaust hole is caused by the aging phenomenon of the two moving parts inside the cylinder and the seal at the seal of the cylinder body.
2. Leakage of the upper and lower parts of the cylinder, due to frequent movement of the sealing ring between the actuator and the cylinder and its actuator, the sealing effect has not been achieved.
3. Air leakage from the solenoid valve on the cylinder may be caused by the high pressure of the pressure reducing valve.
4. The spring in the cylinder is damaged and the force is not in place, which causes the cylinder to leak air.
3. Check whether the solenoid valve is working normally and whether there is air leakage;
Fourth, check whether the positioner works normally and whether there is air leakage;
China cast steel ball valve supplier believes that pneumatic ball valves cannot be closed to zero for two possible reasons. One is actually closed to zero, but the feedback indication is not available. This should be a signal problem, which can be solved by adjusting the positioner. The second is that it is not strictly closed. The big reason is that the valve gasket is damaged or the valve stem is connected Rotate around to get stuck. This type of problem requires removing the valve body and contacting the pneumatic valve manufacturer to replace the gasket and lubricate the rotating part so that it can work properly.
5. Check whether the fixing screws of all connecting parts are tight;
6. Try to avoid too much floating ash from covering the implementing agencies, and the market should keep the working environment clean.
Seven, no feedback signal of pneumatic ball valve
The signal line of the pneumatic ball valve consists of a pair of control signal lines and a pair of feedback signal lines. When the PLC gives a signal to the valve, the signal is converted in the positioner of the regulating valve, and the valve stem is controlled by the air pressure. The stroke of the valve stem transmits the valve opening degree through the feedback signal of the regulating valve.
If the pneumatic ball valve has no feedback signal, use a multimeter to check whether there is voltage at each contact. To check whether the wiring is correct, check whether the signal line is damaged, and check whether the signal line is loose.