When calculating the Cv value of a control valve, how do I convert gauge pressure to absolute pressure?
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When calculating the Cv value of a control valve, the pressures before and after the valve as specified in the process requirements are gauge pressures; however, the units used in the Cv calculation formula are absolute pressures. So how is it possible to convert these values to absolute pressures? Is gauge pressure +0.1 MPa equal to absolute pressure?
Yes, gauge pressure +0.1 MPa is absolute pressure
The original poster is right; if precision isn’t required for adjustment, gauge pressure will suffice
Gauge pressure minus 0.1 MP equals absolute pressure
It is the local atmospheric pressure; generally, 0.1 MP is used as a reference
The differential pressure value is used in the CV calculation formula.
Gauge pressure = Absolute pressure (0.1 MP) + Atmospheric pressure
It’s very practical advice. Thank you to the original poster and those who commented above