Precautions for ball valve maintenance
1、 Re locking at packing
If there is slight leakage at the packing, the valve stem nut must be locked again. But do not lock it too tightly. Usually lock it for 1 / 4 ~ 1 turn, and the leakage will stop.
2、 Replace the valve seat and seal
Keep the valve in the half open position, flush and remove the possible hazardous substances inside and outside the valve body, close the ball valve, remove the connecting bolts and nuts on the flanges on both sides, and then completely remove the valve from the pipeline. Remove the driving device - actuator, connecting bracket, lock washer, valve rod nut, butterfly spring, gnan, wear plate and valve rod packing in sequence.
Remove the body cover connecting bolts and nuts, separate the valve cover from the valve body, and remove the valve cover gasket. Confirm that the ball valve is in the "off" position, which can easily take it out of the valve body, and then take out the valve seat. Gently push the valve stem down from the middle hole of the valve body until it is completely taken out, and then take out the O-ring and the packing under the valve stem. However, be careful to avoid scratching the valve stem surface and the sealing part of the valve body stuffing box.
Clean and inspect the removed parts. It is strongly recommended to replace the sealing parts such as valve seat and bonnet gasket with spare parts package, assemble in the reverse order of disassembly, and cross lock the flange connecting bolts with the specified torque. Lock the valve stem nut with the specified torque.
After installing the actuator, input the corresponding signal to drive the valve core to rotate by rotating the valve stem to make the valve open and close. If possible, please conduct pressure seal test and performance test on the valve according to relevant standards before reinstalling the pipeline.
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