Which device is commonly used as a final control element?

Control valves are commonly used as a final control element in process control systems. Their primary role is to manage the flow of fluids within a system based on signals received from controllers. When a control system determines that a change is necessary—such as increasing or decreasing flow, pressure, or temperature—the control valve adjusts the flow rate to achieve the desired setpoint.

As part of a feedback loop, the control valve acts to directly impact the process variable, ensuring that it remains within desired limits. By precisely controlling the amount of fluid passing through, control valves enable the system to respond to changes in demand or operational requirements efficiently. This direct manipulation of process conditions by the control valve underlines why it is classified as a final control element in industrial settings.

Other devices like pressure sensors, flow meters, and thermometers serve different functions, primarily as measuring devices that provide information about process conditions, rather than actively controlling those conditions. They are crucial to monitoring and data collection but do not directly influence the operation of the system as the control valve does.