Different Between Shut Off Pressure & Differential Pressure for Actuator Sizing?

In PCV & SDV, in that there are two terms

a. Shut off pressure
b. Maximum differential pressure for Actuator sizing

The system sequence is

Vessel A ( Oper.Pres.= 4.5 barg)
-----> PCV( Press. Drop=4 bar)
-----> SDV
-----> Vessel B (oper. Pres.=0.5 barg)

Vessel A design pressure = 12.0 barg

Vessel B design pressure = 4.0 barg

  • PCV - Pressure control valve
    ** SDV - Shutdown Valve

Please suggest the values for the both terms for the PCV & SDV to fill.

a. Specify shut off pressure for valve tightness purposeā€¦ Worst case is design pressure-ATM = 12 bar.

b. Specify maximum differential pressure for actuator design. Large Differential Pressure across control valve, large torque required and larger the actuator (& cost). Actuator also increase with line size. In order to reduce cost, normally you put a small bypass for pressurization purposeā€¦

by JoeWong