A control valve is a power-operated used to regulate or manipulate the flow of fluids, such as gas, oil, water, and steam.
It is a critical part of a control loop and is an example of a final control element. The Control Valve is by far the most common final control element used in industry today.
A control valve can be operated electrically, pneumatically, or hydraulically.
A control valve receives a signal from a controller such as a PLC in order for it to move resulting in a change in flow.
Because the PLC signal is electrical, the control valve may require a device to convert that electrical signal so that it can operate.
Control Valves are used to regulate the flow of steam, water or other fluids to maintain a process such as heating water with steam or cooling down a process using chilled water. They are only one component of a control loop and they rely on other components for proper function (i.e. controller, sensor, transducer, etc.). When properly installed and set-up with appropriate control loop components, these valves provide extremely accurate control.