Operation and Maintenance Methods for the Plunger Valve.
1. Key Points for Commissioning Plunger Valves into Operation.
When a new plunger valve is put into operation, the nuts on the valve cover should be retightened one by one. This operation must be completed within 1 hour after the valve reaches its operating temperature, and the valve should be in the closed position during retightening.
2. Leakage Handling.
If leakage occurs after the plunger valve has been in use for a long time, first close the valve fully (turn it to the end). Then, retighten the fastening nuts on the valve cover slightly in a diagonal and clockwise rotation sequence until the leakage is eliminated. Note: Do not tighten the nuts all the way to the end at one time.
3. Method for Replacing Sealing Rings.
If leakage cannot be eliminated even after the nuts on the valve cover have been tightened all the way to the end, the sealing rings need to be replaced. The specific operation steps are as follows:
- Cut off the upstream fluid to ensure no fluid flows through the valve to be repaired, then open the valve to the fully open position.
- Remove the nuts, rotate the handwheel in the closing direction, and pull out the valve cover together with it.
- When the bolt holes of the valve cover are separated from the studs, rotate the valve cover around the valve stem by a small angle so that the bottom of the valve cover flange faces the tops of the studs.
- Rotate the handwheel in the reverse direction to make the valve cover lean against the studs, and continue rotating the handwheel in reverse until the plunger is pulled out of the upper sealing ring.
- Use a hook to take out the upper sealing ring, metal support ring, and lower sealing ring.
- Replace the old sealing rings with new ones, and install them into the valve body in the order of lower sealing ring, metal support ring, and upper sealing ring.
- After wiping the inner surface of the sealing rings and the outer surface of the plunger clean, position the plunger together with the valve cover and valve stem, screw on the nuts, and press the end face of the valve cover against the upper sealing ring.
- Rotate the handwheel in the closing direction to press the plunger into the sealing rings.
- Perform operations in accordance with the “Key Points for Commissioning Plunger Valves into Operation”.
