The speed and accuracy of pneumatic ball valve fault treatment determine the extent of the production device affected, maintenance personnel's responsibility is to quickly and accurately judge and deal with the fault site, so as to minimize the production affected loss.
The principle of fault handling is: arrive at the site to ask and then look, start, first outside after inside, first repair after want; The processing sequence is: first check the external circuit, air circuit, accessories (solenoid valve, air filter decompression, etc.), then check the pneumatic actuator, and finally check the valve body. The following are several cases of pneumatic ball valve failure:
1、The actuator does not operate.
There are four causes
1)Check whether the air source pressure of the inlet and outlet air filter and decompression device reaches the rated value, increase the air source pressure or replace the air filter and decompression device according to the situation;
2)Check whether the solenoid valve is blocked, whether the air change is normal, according to the situation to clear the plug or replace the solenoid valve;
3)Check whether the air source pressure entering the actuator reaches the rated value and check whether the speed controller is blocked.
4)Check whether the friction of valve sealing parts is too great, or whether there is leakage in the sealing ring.
2、Actuator action, but not enough torque.
Check the adjusting bolts at both ends of the cylinder, adjust according to the closing condition, and lock to the appropriate position.
3、The pneumatic ball valve can be switched on or off, but the action is slow.
Check according to the following:
1)Check whether the speed controller before entering the actuator needs to be adjusted, because changes in the process pipeline and the valve itself require the speed controller to be adjusted as the service life of the valve increases;
2)Check whether there is air leakage in the cylinder. Damage of o-type sealing ring in the cylinder may cause slow action of the valve.
3)Check whether the spring thrust decreases;
4)Check whether the action of cylinder outlet lock valve is sensitive and whether the cylinder exhaust is normal.
4、The actuator operates normally, but the valve does not.
The reasons may be:
1)The valve core and valve seat are stuck;
2)The pipe is blocked;
3)The connection between the actuator and the valve core is worn and detached.
5、The actuator operates normally, but the valve switch is not in place.
The reasons may be:
1)There is a foreign body plug valve in the pipe;
2)Medium pressure difference is too big, the actuator rigidity is small, the valve is not tightly closed;
3)The valve body itself fault causes: if is the ball valve, generally is the sealing surface damage or packing box leakage; If it is lined with fluorine or lined with rubber butterfly valve, generally lined with fluorine or plastic deformation; If the diaphragm valve, generally rubber diaphragm damage; If it is a gate valve, it may be the sealing surface abrade or drive parts stuck, wear, rust.
As the actuator of automatic control system - pneumatic ball valve, its normal operation is related to the production process and the safety of the system, usually do a good job maintenance, very important, otherwise the loss will be your own.