Time of publication:

2023-11-06

When there is leakage or a small amount of leakage inside the gate valve, the first job is to tighten and fix the pressure plate of the valve body, and to strengthen the preload between the pressure plate and the wedge-shaped sealing ring by improving the bolts, which can help the plastic deformation of the sealing ring, thus reducing the gap size between the valve body, the pressure plate and the sealing ring, and avoiding the leakage phenomenon of the valve self-sealing. If the amount of leakage does not change significantly when tightening and fixing the bolts, the tightening measures should be stopped immediately and other treatment measures should be taken instead. Injection of sealant through grease injection hole When there is a small internal leakage of the valve, the sealing surface or packing can be injected with grease through the grease injection hole to temporarily alleviate the internal leakage of the valve. When it is convenient for maintenance, the valve can be disassembled and returned to the factory for maintenance. Welding and strengthening the gap between the end face of the valve body, the stuffing box and the pressure plate To deal with the self-sealing leakage of the valve, it is necessary to do a good job of disassembling the valve handwheel and the valve frame. First, it is necessary to cooperate with the technicians to grasp and adjust the working conditions on the site. Then, after all the valves are opened, the bolts fixed on the valve frame are removed. After the rotary valve frame makes it clear that the valve stem does not rise or fall, the valve frame is removed. After removing the valve frame, the valve body shall be exposed at the pressure plate of the valve, and the gap between the pressure plate and the valve body shall be sealed and welded. In order to consider the reassembly process of the valve frame after blocking the leakage position, the welding gap size shall be between 5mm and 8mm, while the welding angle and the position of the pressure plate shall be 45 degree angle, and shall be polished according to the actual assembly situation. Check actuator zero position The zero position of the actuator is not set accurately, and the valve is not fully closed. Manually fully open and fully close the valve, and then adjust the zero position of the actuator to ensure that the actuator can accurately fully open or fully close the valve. Valve body repair welding or return to factory for repair When there is leakage of the valve body, the valve manufacturer can repair the defects of the valve body, or return to the factory for repair and replacement of the valve body. First of all, the defects of the valve body should be judged. Penetrating cracks, penetrating defects and shrinkage porosity exceeding a certain area are not allowed to be repaired. In this case, the valve body can only be replaced at the factory. For the valve body defects that can be repaired, the appropriate welding process should be formulated, the welding method, electrode material, post-weld stress relief method should be determined, and the welding position should be properly tested to ensure that the repair meets the requirements.