FAIRCHLD Control Valve Maintenance Philosophy

    Control valve has a simple structure and reliable action and other characteristics, 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 frequently maintained and regular maintenance, especially for the use of harsh conditions and important occasions, more attention should be paid to maintenance work. Key inspection parts:

1, the valve body wall for use in high pressure difference and corrosive media occasions of the control valve, the valve body wall, diaphragm valve diaphragm is often subject to media impact and corrosion, must focus on checking the pressure, corrosion resistance.

2, the valve seat control valve work, due to media infiltration, the inner surface of the thread used to fix the valve seat is susceptible to corrosion and make the valve seat loose, inspection should be noted. The valve working under high pressure difference, should also check whether the seal surface of the valve seat is washed out.

3, the spool valve spool is to regulate the work of moving parts, by the medium of the wash, corrosion zui serious, maintenance to carefully check whether the spool parts are corroded, wear, especially in the case of high pressure difference spool wear more serious (due to cavitation phenomenon), should be noted. Spool damage should be replaced when serious, and should also pay attention to whether the stem also has a similar phenomenon, or loose connection with the spool, etc.

4, diaphragm "O" ring and other gaskets. The diaphragm, "O" shaped gasket in the control valve should be checked for aging and cracking.

5, seal packing should pay attention to the polytetrafluoroethylene packing, sealing lubricant grease is aging, with the surface is damaged, should be replaced when necessary.

        Control valve, also known as control valve, is the main type of actuator, by accepting the control signal output from the adjustment control unit, with the power operation to change the fluid flow. Control valves are generally composed of an actuator and a valve. If the power used by the actuator, control valves can be divided into pneumatic, electric, hydraulic three, namely, compressed air as the power source of pneumatic control valves, electric power source of electric control valves, liquid media (such as oil, etc.) pressure as the power of electro-hydraulic control valves, in addition, according to its function and characteristics, there are solenoid valve, electronic, intelligent, field bus type control valves.

    The United States Fairchild regulator imports, regulating valve actuator selection in order to make the normal work of the regulating valve, with the actuator should be able to produce sufficient output force to ensure a high degree of sealing and valve opening. For double-acting pneumatic, hydraulic and electric actuators, there is generally no reset spring. Therefore, the key to selecting an actuator is to find out the maximum output force and the rotating torque of the motor. For single-acting pneumatic actuators, the output force is related to the opening of the valve, and the force appearing on the regulating valve will also affect the movement characteristics, so it is required to establish a force balance throughout the opening range of the regulating valve.