Control Valve Basics
Control Valve What is a control valve A control valve is an instrument that regulates the flow of fluids (oil, water, or gases) as the valve position is changed by moving the stem with help of an actuator. This actuator may be a motor of a pneumatic or hydraulic jack. The control valve is the most commonly used final control equipment in the control loop of an industrial process. The control valve receives a control signal as input from plc or DCS, a controller is used to compare the setpoint and control valve actual position and then decides to open or close the valve according to match the set point. Classes of Control Valve on the base of motion Two main types of valves are according to the motion of the stem. 1. Linear motion 2. Rotary motion 1. Linear motion Linear motion is a movement of valve stem up and down, a common type of linear motion control valve is the Gate valve. 2. Rotary motion A rotary motion valve moves or rotates at an angle usu...