In modern factory automation control, control valves play a crucial role. The production in these factories depends on the correct distribution and control of flowing media. These controls, whether they involve energy exchange, pressure reduction, or simple container filling, all require certain final control elements to be accomplished. Control valves belong to the control valve series and their main function is to regulate parameters such as the pressure, flow rate, and temperature of the medium. They are the final control elements in the process loop. 

How to solve the problem of leakage in electric control valves
1) Adding sealing grease method
For electric control valves that have not used sealing grease, it is possible to consider adding sealing grease to improve the sealing performance of the valve stem.
2) Adding packing method
To enhance the sealing performance of the packing on the valve stem, the method of adding packing can be adopted. Usually, a double-layer or multi-layer mixed packing form is used. Simply increasing the quantity, such as from 3 pieces to 5 pieces, does not yield a significant effect.
3) Replacing PTFE packing with graphite packing method
The widely used PTFE packing has a working temperature range of -20 to 200℃. When the temperature is at the upper or lower limit and changes significantly, its sealing performance drops significantly, it ages quickly, and has a short lifespan. Graphite packing can overcome these shortcomings and has a longer service life. Therefore, some factories have completely replaced PTFE packing with graphite packing, and even for newly purchased control valves, the PTFE packing is replaced with graphite packing before use. However, the backlash of graphite packing is large, and some may even exhibit crawling at the beginning. This must be taken into consideration.
4) Changing the flow direction, placing P2 at the valve stem end method
When the pressure difference (△P) is large and P1 is also large, sealing P1 is obviously more difficult than sealing P2. Therefore, the method of changing the flow direction can be adopted, moving P1 to the valve stem end and placing P2 at the valve stem end. This is more effective for valves with high pressure and large pressure difference. For example, bellows valves usually need to consider sealing P2.
5) Using lens gasket sealing method
For the sealing between the upper and lower covers and the sealing between the valve seat and the upper and lower valve bodies, if it is a flat seal, the sealing performance is poor at high temperatures and pressures, causing leakage. This can be improved by using a lens gasket seal, which can achieve satisfactory results.
6) Replacing the sealing gasket
Up to now, most sealing gaskets still use asbestos boards, which have poor sealing performance and a short lifespan at high temperatures, causing leakage. In such cases, it is advisable to replace them with spiral wound gaskets, "O" rings, etc. Many factories have adopted this approach now.