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Internal view of closed
segment control valve |
The most common final control element in the process industry is a control valve. The control valve influences flowing fluids such as steam, gas, water or chemicals to compensate for load changes and help regulate process variables to a desired set point. Doing this within the desired operating range ensures the quality of the product.
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| Close up of segment shape |
Sensors and transmitters collect process information to reduce the effect of load disturbances and their relationship to a desired set point. Controllers then process this information and adjust the control valve to move the variable back to set point. A control valve is the component that implements the adjusts the process to achieve set point.
Control valves are typically an assembly of valve, internal trim, a pneumatic or electric actuator (that provides power to operate the valve) and additional accessories such as positioners, transducers, regulators or limit switches.
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Cutaway view of open
segment control valve |
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Segment control valve is a "quarter-turn" valve with a "sliced" or "segmented" ball. The shape of the segment offers linear control, a sweeping or cutting action when closing (making it a good choice for surries or fibers) and a tight shutoff. Segment valves are sometimes mistakenly referred to as a "V-Port valve" or "Characterized valve", which actually refer to ball valves with modified or cutaway balls.
To better understand how segment control valves work, see this video:
