PRECISION GAS FLOW METERS & GAS FLOW CONTROLLERS

# Are there conversion factors for changing operation conditions?

Are there conversion factors for changing operation conditions?

Conversion factors for changed operation pressure:

F = Factor
P2 = New operation pressure
P1 = Previous operation pressure according to specifications on the measuring tube

Example:
Specification on the measuring tube [P1]: Pressure 2 bar a
New [P2]: Pressure 6 bar a

Scale value x 1.732 = effective flow at ambient pressure (1013 mbar abs) at an operating pressure of 6 bar a in the measuring tube (5 bar gauge pressure).

Conversion factors for changed operation temperature:

F = Factor
T1 = Operation temperature in °K (according to specifications on the measuring tube)
T2 = New operation temperature in °K

Example:
Specification on the measuring tube [T1]: Temperature 20°C + 273°K = 293 °K
New [T2]: Temperature 80°C + 273°K = 353 °K

Scale value x 0.911 = effective flow at ambient temperature (20°C) at an operation temperature of 80°C.

Conversion factors for changed gas type:

F = Factor
Rho1 = Density of the gas specified on the measuring tube
Rho2 = Density of the new gas

Example:
Specification on the measuring tube [Rho1]: N2, density 1.25 g/normliter
New gas type [Rho2]: Ar, density 1.78 g/normliter

Scale value x 0.838 = effective flow when using argon.

Please note that these are only approximate conversion factors!