Emerson Exchange 365

I want to ask you a question about “selected Cv“ and “calculated Cv“ for regulator+blanketing

to include the added effect of the regulator by calculating and including the Cv for the entire regulator+blanketing system.

• If the KRISS report shows the capacity curves of the regulator+blanketing, you should be able to calculate the Cv of regulator+blanketing using KRISS report curves
• This item is important, because after adding the regulator, Cv (venting capacity) of the regulator+blanketing valve is less than the Cv (venting capacity) of the blanketing valve alone. the Cv (venting capacity) of regulator+blanketing valve.

Please note the following values:

Cv for combination of Regulator and Blanketing Valve

P1 = Inlet Pressure in psia, C2 = Correction Factor for specific heat ratio(Air=1.0), V = Flow rate in Nm3/Hr, X=0.66 for P1≤3.288 Bara, 0.69 for P1>3.288Bara, G =Specific Gravity , T =˚K (Tempeture)

density = density of N2 @ T=20 C and P=1atm = 1.16 kg/m3.
-> V = mass flow rate / 1.16

For example:

required mass flow rate = 518 kg/hr -> required volumetric flow rate = 518/1.16 = 447 m3/hr

-> calculated Cv = 447/(263*7*(0.69/(0.97*330))^0.5)=5.23

By this equation I could calculate the “calculated Cv “

And I would like to know that what is“ selected Cv“ .

Thank you very much

Nushin