The input signals of pneumatic control valve are 4~20mA and 0~5V or 10V, but the voltage signal is greatly attenuated and interfered during transmission. Therefore, 4~20mA signal is the most commonly used. First, after the program runs, the analog output (AO) module outputs a 4-20mA signal, which is directly connected to the regulating valve after passing through the signal isolator.

Pneumatic control valve is driven by compressed air to realize on-off or proportional adjustment. As the actuator, the cylinder receives the control signal of industrial automation control system to complete the adjustment of various process parameters such as flow rate, excitation and temperature of pipeline medium.

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Precautions for installation of pneumatic control valve

1. During installation, always observe the installation instructions and precautions of pneumatic control valve;

2. The working environment temperature of the regulating valve shall be (-30 ~+60), and the relative humidity shall not be greater than 95% and 95%;

3. Before and after the control valve, there should be straight pipe sections, the length of which should not be less than 10 times of the pipe diameter (10D), so as to avoid the short straight pipe section of the valve affecting the flow characteristics;

4. Please read the instruction before installing the valve. The user manual introduces the product, as well as the safety precautions and preventive measures that should be paid attention to before and during installation;

5. Make sure that the pipeline is clean: foreign objects in the pipeline may damage the sealing surface of the valve, even hinder the movement of the valve core, ball or butterfly plate, resulting in the valve not being closed correctly. In order to reduce the possibility of dangerous situations, it is necessary to clean all pipes before installing valves.

References:

Baidu encyclopedia-pneumatic regulating valve