d) Stem travel
e) Valve body
g) Gland packing
Trim : Trim is a matched pair of ‘plug’ and ‘seat’
CV : The amount of water flow in gallons through the control valve when the valve port is fully open and the pressure differential across the valve is 1 Psi.
Actuator : The drive unit having a diaphragm and a piston that operates the valve stem.
Stem travel: The scale that shows the stem movement in inches or centimeter.
Valve body: The bottom portion of a control valve installed on a pipeline to control a process. The valve body contains a trim, pipe flange, bonnet, gaskets, guide bush, gland packing, lantern ring, grease, cooling fins…etc.
Yoke : A portion of the actuator which connects the actuator to the valve body carrying a stem travel plate.
Gland packing: A sealing system in the valve body which prevents the process fluid coming out through the valve stem.