The
control valve has the characteristics of simple structure and reliable action, but because it is in direct 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 repaired, especially for harsh and important operating conditions. On occasion, more attention should be paid to maintenance work. Key inspection areas:
1. The inner wall of the valve body
For control valves used in high pressure difference and corrosive media, the valve body wall and the diaphragm of the diaphragm valve are often impacted and corroded by the medium, and the pressure 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 for fixing the valve seat is easily corroded and the valve seat is loosened, so attention should be paid during inspection. For valves that work under high pressure difference, it is also necessary to check whether the sealing surface of the valve seat is damaged.
3. Spool
The valve core is a movable part during adjustment work, and it is most seriously eroded and corroded by the medium. During maintenance, it is necessary to carefully check whether the various parts of the valve core are corroded and worn, especially in the case of high pressure difference. The wear of the valve core is more serious. (Due to cavitation), 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 also has a similar phenomenon, or the connection with the valve core is loose.
4. Diaphragm
"O" rings and other gaskets. The diaphragm and "O"-shaped gasket in the control valve should be checked for aging and cracking.
5. Sealing packing
Pay attention to whether the PTFE packing and sealing grease are aging, and whether the mating surface is damaged, and should be replaced when necessary.
