Six solutions to the leakage of the control valve
1) Increasing the sealing grease method
For valves that do not use sealed grease, can increase the sealing grease to improve stem seal performance.
2) Increasing the packing method
In order to improve the sealing performance of the packing on the stem, a method of increasing the packing may be used. Usually using double-layer, multi-layer mixed filler form, simply increase the number, such as 3 to 5, the effect is not obvious.
3) Replace the graphite packing method
Large use of PTFE filler, because of its operating temperature is in the range of -20 ~ +200, when the temperature is in the upper and lower limits, changes in the larger, the seal will be significantly reduced, aging fast, short life. Flexible graphite fillers can overcome these shortcomings and long service life. So some of the factory all the PTFE filler to graphite filler, and even the newly purchased control valve will be one of the PTFE filler into graphite filler after use. But the use of graphite filler hysteresis, and some also have a crawling phenomenon, which must be considered.
4) Changing the flow direction, set P2 in the stem end method
When the △ P is large, P1 is large, the seal P1 is clearly more difficult than the seal P2.Therefore, can be taken to change the flow direction, P1 in the stem end to P2 at the stem end, which is high pressure, Large sanitary check valves are more effective, such as bellows valves that should normally be considered for sealing P2.
5) Using lens pad sealing method
For the seal of the upper and lower covers, the valve seat and the upper and lower valve body seal. If the plane seal, under high temperature and high pressure, poor sealing, causing leakage, you can use the lens pad seal, can get satisfactory results.
6) Replacing the gasket
So far, most of the gasket is still using asbestos board, at high temperatures, poor sealing performance, life is short, causing leakage. In this case, you can use the winding gasket, “O” ring, now many plants have been used sanitary valves.