What is the difference between three-way merging control valves and three-way diverging control valves?
Three-way control valves, available in merging and diverging forms, consist of a pneumatic/electric actuator and a three-way merging or three-way diverging control valve. There are electric three-way control valves and pneumatic three-way control valves commonly used.
Valve positioners are the devices that are used to put a valve in the right positioner by increasing and decreasing the air load pressure on the actuator. The valve positioner senses the exact position of the valve and communicates to the actuator to drive the valve.