7/14/2015 9:03:10 AM

What is a control valve?
Control valve is final control element in the process control industry. It handles flowing fluid like Steam, Gas, Water, Liquids to set right the process errors and regulate the process as per the desired set point.
Where should one use a control valve?
-For Flor Isolation
-For controlling the flow rate  
-Flow diverting or Flow Mixing
-Preventing back flow,
-Controlling pressure,
-Control temperature
What is CV ?
Maximum Flow of Water in USGPM thru’ CV at 20 Deg.C @ 1 psi DeltaP across it.
What are the most important parts of a control valve?
Body, Bonnet, Trim (Seat ring, Plug and Spindle), Stuffing Box,
What is the function of each of these important parts?
Body is the main part of control valve which has internal like trim, seals & helps the flow to create proper flow path, Bonnet : Connecting part between body and Actuator, Trim : Heart of Control valve helps to control the fluid as per set point, Stuffing Box : Helps to avoid any fluid coming out thru bonnet area thus eliminates any undesirable leakages,

What is meant by an actuator?
Makes the valve to operate thru different energy inputs like Pneumatic, Electric Hydraulic etc..,
How does an actuator work?
Actuator make the valve spindle to move up and down depending upon the signal it receives from the positioner.
What are the types of actuators?

Pneumatic (Single acting //Double acting), Pneumatic Piston actuators, Electric Actuators, Hydraulic Actuators
What are the types of control valves?

Globe control valve, Butterfly valves, Segmented V notch Ball Valves, Self-Actuated diaphragm valves, Eccentric Plug valves, Angle valve, 3-Way valves
What is a positioner?

Positioner is a component which make the valve to open or close to eliminate the process error and achieve the set point by generating input signals.

What is the function of a positioner?

Positioner measure the actual position of valve and take the command from controller, compare both the signals and make the valve to move either in open direction or close direction to correct the process error.