Regulating Fluid Flow with Control Valves Control valves are essential devices that regulate fluid flow in industrial processes, receiving signals from controllers like PLCs or DCS to adjust the flow rate towards a desired setpoint. They can be operated electrically, pneumatically, or hydraulically and come in two main types: linear motion (e.g., gate valve) and rotary motion (e.g., butterfly valve). The actuator connected to the valve stem provides necessary force for movement; pneumatic actuators are most common due to their reliability.
Fail-Safe Operation and PID Tuning In case of control signal loss, control valves enter fail-safe modes—either closing or opening depending on design requirements. The extent of valve movement during changes in flow rate is influenced by factors such as pipe diameter and percentage change. Proper tuning through PID control within PLC systems ensures accurate response adjustments for varying conditions.