Regulating valves play an important role in the automatic control of modern plants, and the production of these plants depends on the proper distribution and control of the flowing media. These controls, whether energy exchange, pressure reduction, or simple container feeding, require some final control components to complete. The regulating valve belongs to the series of control valves. The main function is to adjust the pressure, flow, temperature and other parameters of the medium, which is the final control component in the process loop.
How to solve the problem of leakage of electric control valve
1) Increase the sealing grease method
For electric control valves that do not use sealing grease, consider adding seal grease to improve stem sealing performance.
2) Add filler method
In order to improve the sealing performance of the filler to the valve stem, a method of increasing the filler may be employed. Usually it is a double-layered, multi-layered mixed filler form, which simply increases the number. For example, if you increase 3 pieces to 5 pieces, the effect is not obvious.
3) Replacement of graphite filler method
The PTFE filler used in a large amount, because its working temperature is in the range of -20 to 200 ° C, when the temperature is changed at the upper and lower limits, the sealing property is obviously lowered, the aging is fast, and the life is short. Flexible graphite fillers overcome these shortcomings and have a long service life. Therefore, some factories have changed the PTFE filler to graphite filler, and even the newly purchased regulator valve has replaced the PTFE filler with graphite filler. However, the use of graphite fillers has a large backlash, and some of them also have creeping phenomenon at the beginning, which must be considered.
4) Change the flow direction, set P2 at the stem end method
When ΔP is larger and P1 is larger, the seal P1 is obviously more difficult than the seal P2. Therefore, the method of changing the flow direction can be adopted, and the P1 is changed to the P2 end at the valve stem end, which is high in pressure and pressure difference. Large valves are more effective. For bellows valves, seal P2 should normally be considered.
5) Using the lens pad sealing method
For the sealing of the upper and lower covers, the valve seat is sealed with the upper and lower valve bodies. If it is a flat seal, under high temperature and high pressure, the sealing performance is poor, causing leakage, and the lens pad seal can be used instead, and satisfactory results can be obtained.
6) Replace the gasket
Up to now, most of the sealing gaskets still use asbestos sheets. At high temperatures, the sealing performance is poor and the service life is short, causing leakage. In this case, you can use a wound gasket, an "O" ring, etc., which is now used in many factories.
