Reason 1: The sealing surface leaks
1. There are sundries in the butterfly plate and sealing surface
2. The closing position of the butterfly plate and the sealing surface is not properly matched
3. The flange bolts on the outlet side are not uniformly stressed or not according to the requirements of Figure 1
4. The pressure test direction is not as required in Figure 1
Elimination method:
1. Eliminate impurities and clean the inner cavity of the valve
2. Adjust the adjusting screw of the worm gear or electric actuator to achieve the correct closing position of the valve
3. Check the mounting flange plane and bolt tightening state, and they should be evenly tightened
4. Apply pressure in the direction of the tip seal
Reason 2: The method of eliminating leakage on both ends of the valve
1. Failure of the sealing gaskets on both sides
2. The tightening force of the pipe flange is uneven or not tightened
3. The upper and lower sealing gaskets of the sealing ring fail
Elimination method:
1. Replace the gasket
2. Tighten the flange bolts (evenly stressed)
3. Remove the pressure ring of the valve, replace the sealing ring, and the invalid gasket