Motorized control valves are automated valves that can be remotely operated using electric actuators. They allow fluid flow levels to be adjusted automatically based on input signals. In many industrial processes, motorized control valves are replacing traditional manual valves due to their precise control capabilities.

Main Components : A Motorized Control Valves consists of three main components - the valve body, the actuator and the positioner. The valve body contains the plug or gate that can restrict or allow fluid flow. Electric actuators powered by AC or DC motors provide the torque needed to open or close the valve. Positioners are feedback devices that ensure the valve achieves the exact setpoint. They monitor valve position using potentiometers and make corrections using the actuator.

Actuator Technologies Used in Motorized Valves

The most common actuator types are pneumatic actuators and electric actuators. Pneumatic actuators utilize compressed air and are cost-effective but have lower accuracy. Electric actuators can be rotary or linear. Rotary actuators use gearing or worm drives to convert the motor's rotary motion to linear stem movement. Linear actuators have a rack-and-pinion or scotch yoke mechanism. They provide greater precision for applications involving variable flow. New valve actuators increasingly use brushless DC motors for their reliability.

Applications in Process Industries

Motorized control valves have numerous applications in process industries like oil & gas, power, chemicals, food & beverage and more. In the petrochemical industry, they are used for throttling crude and product pipelines. Power plants rely on them to control steam, water and fuel flows. In manufacturing, they dose chemicals and regulate flows in mixing vessels. Water and wastewater treatment facilities use motorized valves for filtration, aeration and distribution tasks. Their auto-calibrating positioners ensure process variable control.

PLC and DCS Integration

Modern motorized control valves connect to distributed control systems (DCS) or programmable logic controllers (PLC) via industry standard communication protocols. This allows the process control system to remotely operate the valves according to feedback from sensors and controllers. Protocols like HART, Fieldbus and Profibus enable two-way communications for valve diagnostics as well. Process automation has become highly integrated, with control valves as critical actuating devices.

Benefits Over Manual Valves

Compared to manual valves that need an operator to open or close, motorized control valves offer many advantages. They provide more precise level and pressure control with less overshoot. automated operation improves process consistency. Maintenance needs are reduced since actuators perform the valve-turning function. Digital position sensors eliminate errors from handwritten logs. Integration with control systems enables remote monitoring and operation from any location. Overall, motorized control valves increase productivity and efficiency in industrial facilities.

As process automation increases across industries, motorized control valves will continue gaining prominence over traditional manually operated valves. Their ability to precisely regulate fluid parameters in sync with PLCs/DCSs makes them well-suited for advanced process control applications. With continued improvements in electric actuator and positioner technologies, motorized valves will keep enhancing flow control accuracy and flexibility for industries worldwide.

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