How to calculate the pressure drop across a fully open valve

Issue

How to calculate the pressure drop across a fully open valve

Product Line

Field Devices

Environment

Valves

Cause

End user wants to calculate the pressure drop across a  valve for a given flow rate.

Resolution

1. Select a valve to suit the application and note its Kvs. note if the figure is Cvs then Cvs * 1.03 = Kvs

2. Flow rate is required.

P (bar) = (m3/hr / Kvs) squared.

or

P (bar) = ( (l/s * 3600 /1000) / Kvs) squared.

To convert to Bar to Kpa:  1 Bar = 100 Kpa