Automatic control valve

The advantages of electric control valves are their simple structure, wide range of applications, good controllability during the regulation process, and accurate stroke. The disadvantage is that it may generate electric sparks or static sparks. The advantages of pneumatic control valves are their rapid response, enabling them to quickly execute control commands, as well as their safety, since they do not generate electric sparks. But the disadvantages are complex control, high cost, and a complex structure. Therefore, electric valves are mostly used for regulation, but pneumatic valves are still employed in pipelines that require rapid opening and closing, as well as in pipelines for flammable and explosive gases and chemical hazardous materials.

1. Generally, for control valves with a diameter of 200 MM or less and no special requirements regarding operating speed, pneumatic actuators are chosen; whereas for valves with larger diameters, higher torque, or specific requirements concerning operating speed, electric actuators are used. 2. The choice of electric or pneumatic actuators also depends on the actual conditions of the enterprise. In applications in the petrochemical industry, where conditions are harsh and there are various corrosive gases as well as high requirements regarding explosion protection, it is recommended to opt for pneumatic actuators, as they are more economical and suitable for such situations ； In applications such as power plants where fast response speeds and high torque are required, it is more economical to use electric actuators. 3. The choice of actuator is also directly related to whether a company has an air compressor station or not. If a company does not have such a station, it would be uneconomical to install one solely for the new control valves; therefore, using electric actuators is a more cost-effective option.

On the 2nd and 3rd floors, experts as well – it seems there are differing opinions regarding execution speed. May I ask a layperson to provide an example to illustrate this, please? It seems that the actuator of the bottom valve (plunger valve) used for discharging material from the PVC polymerization reactor is pneumatic, which provides a faster operating speed and allows for adjustment. The annoying noise generated during operation can be addressed by installing solenoid valves with noise reduction functions.