I have been doing a small sizing task for the actuator
I have been given the following:
the control valve (EZ) is unbalanced
the port diameter: 1"
Classs II shutoff
The available supply: 0-18 psig
Stem diameter: 3/8 "
I would like to proceed with 657 actuator:
P1=13 psig and DP is 5 psig
So Unbalance force will be (P1-P2)A(area of port) + P2*As(area of stem) = 6.43 pound
Seating force required : 62.8 pound ( 20 pound per a inch of port)
and app 50 pound may go to PTFE Packing
the overall force will be: 119.23 pound.
The smallest actuator area is 46 inches so 2.5 psia can easily move the actuator which is less than an atm where the accepted practice is to use 3-15 psig pressure 3 psig is 17 psia app which is far greater than 2.5 psia
Can I use the 657 actuator in here?