1. The main reason for this is the expensive maintenance fee, so the operating managers do not maintain
ball valves. Or lacking of scientific management and preventive maintenance, the valve will have a failure in advance.
2. Wrong operation and maintenance will also cause the leakage.
3. The remains of construction scratches the sealing surface in normal operation and it will also lead to the leakage.
4. Improper cleaning can make the sealing surface broken.
5. The seat and sphere locked together because the ball valve hasn’t been maintained and operated for a long time. Therefore, when opening or closing it, the sealing surface will be damaged and cause the leakage.
6. No matter what kind of ball valves, generally, if you don't open and close it completely, two to three degree inclination may cause leakage.
7. Many large caliber ball valves have stem stop block. Due to the long period operation, rust, dust, oil paint and other things will pile up on the block so that the valve can not be rotated completely. If the valve is buried, it will pile up more impurities and give rise to the leakage easier.
8. Lacking of regular maintenance will make the sealing grease dry and hard. Therefore, it will block the seat movement and cause the sealing failure.
