Working Principle of Pneumatic Regulating Valve

Working Principle of Pneumatic Regulating Valve

Working Principle of Pneumatic Regulating Valve

Simply speaking, it is realized by compressed air. In practical application, it is very important to understand the working principle of pneumatic control valve.

Pneumatic control valve is driven by compressed air as power source, cylinder as actuator, and with the aid of electrical valve positioner, converter, solenoid valve and other accessories, realizes the switch volume or proportional regulation, and receives the control signal of industrial automation control system to complete the regulation of pipeline medium flow, pressure, temperature and other process parameters.

Pneumatic control valve is characterized by simple control, fast response, intrinsic safety, and no need to take additional explosion-proof measures.

Pneumatic control valve operates in two types: open and closed. Air to open is when the pressure above the diaphragm head increases, the valve moves towards the direction of increasing opening. When the upper limit of input pressure is reached, the valve is in full open state. Conversely, when the air pressure decreases, the valve moves towards the closing direction. When there is no air input, the valve is completely closed.

Sometimes, air-opened valves are also called Fail to Close FC. The movement direction of air to Close is just opposite to that of open air. When the air pressure increases, the valve moves towards the closing direction; when the air pressure decreases or does not exist, the valve moves towards the opening direction until it is fully open. The opening or closing of pneumatic control valve is usually realized by the positive and negative action of the actuator and the different assembling ways of the valve structure.