In construction period
1. Something wrong with transportation and hoisting and it gives rise to the overall damage.
2. When leaving the factory, there is no measure to be taken to dry the natural gas
ball valve and to do antiseptic treatment, so, the sealing surface is rusted.
3. Lacking protection on construction site. No blind plate is installed on both ends of the natural gas ball valve and impurities get into the valve seat, such as rain, sand and so on.
4. There is no grease poured into valve seat during installation and this will make the impurity get into the valve seat .Or the valve seat is burned during welding.
5. The natural gas ball valve doesn't install well and damage the sphere. During the welding process, if the valve isn't in the right position, weld spatter will damage the sphere and further lead to the damage of seat.
6. The remains of construction scratches the sealing surface, like welding slag and other things.
7. If there is a certain angle deviation between valve and stem drive socket or other accessories, the valve will have leakage problem, too.