With the rapid development of the national economy, control valves are increasingly used in the process of automation development. Gas regulator valves are mainly used to regulate the flow, pressure, and liquid level of the medium. Based on the position signal, the automatic control valve opens to achieve the regulation of medium flow, pressure, and liquid level.
With the help of accessories such as electric valve positioners, converters, solenoid valves, and positioners, the valve is driven to achieve on-off or proportionate regulation, receive control signals from industrial automation control systems, and regulate pipeline media; flow, pressure, temperature, and other process parameters. The characteristics of pneumatic control valves are simple control, rapid response, basic safety, and no additional explosion-proof measures are required.
Pneumatic actuators can be divided into single-acting and double-acting types. Single-acting actuators can automatically position themselves to the open or closed state of the valve, at the origin or in case of sudden failure. Gas regulator valves are divided into normally open and normally closed, pneumatic control valves can be air-opened or air-closed, usually by the positive and negative effects of the actuating mechanism and different combinations of valve structures.
In the open type (double-closed), when the diaphragm pressure increases, the valve increases its opening direction. When the input pressure reaches its limit, the valve is fully open. Conversely, when the air pressure decreases, the valve moves in the closing direction, and when there is no air input, the valve is completely closed. Generally, we call the pneumatic control valve a fail-close valve. The action direction of the air-closed type is the opposite of that of the air-opened type. When the air pressure increases, the valve moves in the closing direction, and when the air pressure decreases or does not decrease, the valve moves in the opening direction or fully opens.
The actuator is the thrust component of the control valve. It generates corresponding thrust according to the size of the control signal pressure and drives the regulator mechanism. The valve body is the regulating component of the pneumatic control valve. It directly contacts the regulating medium and regulates the flow of the fluid.
It is simple to control, responds quickly, and is inherently safe, without the need for additional explosion-proof measures. Gas regulator valves use compressed air as the power source to achieve on-off or proportional regulation. They use cylinders as actuators and receive control signals from industrial automation control systems to regulate the flow, pressure, temperature, and other process parameters of pipeline media.