Hi, this is the little housekeeper, industrial automation in industrial equipment, control valve to gradually become an indispensable part, control valve is the actuator in automatic control system, and the application of control valve is good or bad, in addition to product quality, the user is correct installation, use, maintenance, correct calculation, selection is very important, we come to you in detail introduce control valve selection,

The principle of control valve selection
1, according to the process conditions, select the appropriate structure form and material,
2, according to the characteristics of the process object, select the control valve flow characteristics,
3, according to the process operating parameters, select the appropriate control valve diameter size,
4, according to the requirement of the process, select the desired auxiliary device,
5, choose the actuator, the response speed of the actuator should be able to meet the process
To control the requirements of the travel time: chooses the control valve actuator should be of sufficient valve stroke and process for the leak amount level requirements, on some occasions, such as selection pressure control valve (including exhaust valve), should consider the actual possible differential proper amplification, which can provide larger force required for actuators, otherwise, may be when the abnormal situation on craft, the actual before and after the control valve pressure difference is bigger, will be the risk of not close or can't open,

The maintenance of control valve
Control valve has simple structure and reliable etc, but because of its direct contact with the process medium, its performance directly affect the quality system and environmental pollution, so the valve must be regularly maintenance and preventive maintenance, especially to use conditions and important occasions, more should pay attention to the maintenance work, the key inspection area
1, the body wall
For use in high pressure and corrosive medium control valve, the valve body wall, diaphragm valve diaphragm often impacted by the media and corrosion, must key check pressure, corrosion situation,
2, the seat
Control valve is working, for medium infiltration, the fixed seat with the thread is susceptible to corrosion on the inner surface of the seat is loose, check should be pay attention, to work under high pressure differential valve, also should check whether the valve seat sealing surface is bad,
3, the valve core
Valve core is adjust the moving parts of the job, by the medium of erosion and corrosion is most serious, should carefully check whether all parts of the valve core when maintenance is corrosion, wear and tear, especially under the condition of the high pressure difference of valve core wear more serious (due to cavitation phenomenon), should be note that the valve core is badly damaged should be replaced when, also should pay attention to whether the valve stem has a similar phenomenon, loose or connected to the valve core, such as
"O" ring and other 4, diaphragm seal, applicants should diaphragm control valve, "O" shape gasket is aging, split,
5, packing
Attention should be paid to ptfe packing, sealing grease is aging, mating surface is damaged, should be replaced when necessary,