How to maintain control valves

The control valve has the characteristics of simple structure and reliable action, but because it is directly in contact with the process medium, its performance directly affects the quality of the system and environmental pollution, so the control valve must be regularly maintained and overhauled, especially for harsh and important conditions. In some cases, more attention should be paid to maintenance work. Key areas to check:
1. The inner wall of the valve
For control valves used in high pressure differential and corrosive media, the inner wall of the valve and the diaphragm of the diaphragm valve are often impacted and corroded by the medium, so the pressure resistance and corrosion resistance must be checked.
2. Valve seat
When the control valve is working, due to the infiltration of the medium, the inner surface of the thread used to fix the valve seat is easily corroded and the valve seat is loose, so attention should be paid to it during inspection. For valves working under high pressure difference, check whether the sealing surface of the valve seat is damaged.
3. Spool
The spool is a movable part during adjustment work, and it is most severely eroded and corroded by the medium. During maintenance, it is necessary to carefully check whether the parts of the spool are corroded and worn, especially in the case of high pressure difference. The wear of the spool is more serious. (Due to cavitation phenomenon), attention should be paid. When the valve core is seriously damaged, it should be replaced. In addition, attention should be paid to whether the valve stem has similar phenomena, or the connection with the valve core is loose.
4. Diaphragm
"O" rings and other seals. Check whether the diaphragm and "O"-shaped gasket in the control valve are aging or cracked.
5. Seal packing
Pay attention to whether the PTFE packing and sealing grease are aging, and whether the mating surface is damaged, and they should be replaced when necessary.
The regulating valve, also known as the control valve, is the main type of actuator. By receiving the control signal output by the regulating control unit, the fluid flow is changed by means of power operation. Regulating valves generally consist of an actuator and a valve. According to the power used by its matching actuator, the regulating valve can be divided into three types: pneumatic, electric and hydraulic, that is, the pneumatic regulating valve with compressed air as the power source, the electric regulating valve with electricity as the power source, and the liquid medium. (such as oil, etc.) Pressure-powered electro-hydraulic control valves. In addition, according to their functions and characteristics, there are solenoid valves, electronic, intelligent, and field bus-type control valves.