1. The processing accuracy of the wedge-shaped sealing ring is low, which leads to internal leakage of gate valve. Wedge seals can be divided into two categories, the first is a hard seal, also called the metal wedge ring; the second is a soft seal, or a composite graphite wedge ring. If the accuracy of the wedge-shaped sealing ring is defective, it is easy to cause internal leakage of the gate valve.

2. Unstable production operation conditions cause internal leakage of the gate valve. The working conditions of the valve production and operation process are unstable, and its pressure and ambient temperature may change significantly. This makes the sealing ring bear greater impact pressure, scouring force and deformation, resulting in a bigger gap between the sealing ring and the valve body. The bigger it was, the valve would leak inside.

3. The valve maintenance quality is not closed, resulting in internal leakage of the gate valve. In the process of disassembling the valve for maintenance, the staff did not clean the sealing surface when installing the wedge sealing ring, leaving some fine particles and impurities. These fine impurities may scratch the sealing surface during the operation of the valve. Once sealed Penetrating scratches on the surface will cause valve leakage.

4. The wedge-shaped sealing ring is corroded by the medium causing internal leakage of the gate valve. When designing wedge-shaped sealing rings, more attention should be paid to the strength and corrosion resistance of the sealing ring. The surface hardness of the sealing ring should be lower than that of the bonnet. It must also conform to the plastic deformation that can occur under external force conditions. The medium may also corrode the wedge-shaped sealing ring during operation, which may cause leakage of the gate valve.

5. The gate valve actuator switch is not in place, causing the gate valve to leak. The opening and closing of the gate valve is controlled by the actuator structure. The actuator relies on liquid, gas, electricity or other energy sources and converts it into a driving function through a motor, cylinder or other device to drive the valve to the fully open or fully closed position. If the execution structure is not opened or closed in place, the gate valve cannot be fully opened or closed, resulting in internal leakage of the valve.

6. The valve body defect causes the gate valve to be exposed. Valve body castings often have casting defects, such as: pores, pinches, cracks, trachoma, etc. If these defects are not found in the factory, or if correct repair measures are not taken, the valve will leak during on-site use.