The control valve is the most common final control device in the process, The control valve regulates the flow of a fluid, such as gas, steam, water, or chemical mixture, to compensate for load disturbances and make the controlled process variable as close as the desired setpoint.

There are three typical types of actuated control valves in the process, pneumatically actuated, electric actuated/motorized actuated, and hydraulic actuated. The working principles of the valve are similar, but a bit different from the actuator part with different ways to operate.