Instruction manual

Instruction Manual Smart-Trak
®
50 Series
IM-50 Rev. A.2 32
Appendix A: Gas Tables & K-Factor Calculations
K-Factor Calculations--
Using Smart-Trak
®
50 Series with Other Gases
If you will be using Smart-Trak
®
50 Series with a gas other than as calibrated, you may
use the tables below. They provide K-factors and thermodynamic properties of gases
commonly used with mass flow meters and controllers. This is particularly useful if the
actual gas is not a common gas or if it is toxic, flammable, corrosive, etc. The tables can
also be used to interpret the reading of a flow meter or flow controller that has been
calibrated with a gas other than the actual gas.
Before applying the tables, set the instrument for Air. Then, the following fundamental
relationship may be used:
Q
1
/Q
N
= K
1
/K
N
Where:
Q = The volumetric flow rate of the gas referenced to standard
conditions of 0°C and 760 mm Hg (sccm or slm),
K = The K-factor from the following tables, referenced to Air
( )
1
= Refers to the “actual” gas, and
( )
N
= Refers to the “reference” gas, Air in this case.