3. The leakage of sealing surfaces
Causes:
1. The grinding of the sealing surface is uneven, and the sealing line cannot be formed.
2. The connection part between the valve stem and the closing part is suspended, incorrect or worn.
3. Valve stem bending or improper assembly make the closing part skew or not in the center.
4. The quality of the sealing surface material is not appropriate or the
valves are not selected according to the working conditions.
Maintenance methods:
1. According to the working conditions, we can correctly select the materials and types of swing gaskets.
2. Carefully adjust and smoothly operate.
3. The bolts should be twisted evenly and symmetrically. When necessary, the torsion spanner should be used. Flanges and thread connections should have a certain reserved tightening clearance.
4. The gasket assembly should be aligned in the center, and the force should be uniform. The double gaskets are not allowed to lap and use.
5. When installing gaskets, we should pay attention to cleaning. The kerosene should be used to clean the sealing surface, and gaskets should not fall to the ground.
4. Leakage at the connection of the sealing ring
Causes:
1. The sealing ring is not tightly pressed
2. The sealing ring and body weld together, but surfacing welding quality is poor.
3. The sealing ring connecting threads, screws and pressure rings loose.
4. The sealing ring is connected but corroded.
Maintenance methods:
1. The leakage at the sealing rolling place should be injected with adhesive and then be fixed by rolling.
2. The sealing ring should be repaired according to the welding specification. When the surfacing place cannot be repaired, the original surfacing and processing should be removed.
3. Remove the screws, clean the pressure ring, replace the damaged parts, grind the sealing surface with the connecting seat and reassemble. The parts with large corrosion can be repaired by welding, bonding and other methods.
4. If the seal ring connection surface is corroded, it can be repaired by grinding, bonding and other methods. It can not be repaired with the replacement of the sealing ring.
5. Leakage caused by the falling off of the closing parts
Causes:
1. Poor operation makes the closing part stuck and the connection be damaged and broken.
2. The closure of the connection is not strong, loose and fall off.
3. The choice of connector materials is wrong. It can not withstand the corrosion of the medium and mechanical wear.
Maintenance methods:
1. Close the valve with soft force. Open the valve which can not exceed the upper dead point. After the valve is fully open, the hand-wheel should be reversed a little.
2. The connection between the closing part and the valve stem should be firm, and the threaded connection should have a stop part.
3. The fasteners connected between the closing part and the valve stem should withstand the corrosion of the medium, and have a certain mechanical strength and wear resistance.
