Omega Engineering FLR1000 - Manual (Page 14)

pg. 14 of 29
4. Zero Adjustments
It is impossible for there to be any zero drift so zero adjustments are
never required.
5. Recalibration
Please contact the Omega Engineering Service Department if your flow
sensor or flow meter needs recalibration.
6. Using Flow Sensors or Flow Meters with Different Gases
The FLR 1000 Series will operate with most gases subject to compatibility
of the wetted parts. For information about calibrating for Hydrogen or
Helium, contact the Omega Engineering Service Department.
Units are calibrated with AIR at a pressure of 760mmHg and temperature
of 23°C unless otherwise detailed on the calibration certificate. Using other
gases will effect the calibration. The amount of calibration error will
depend on the characteristics of the gas being flowed.
The flow reading correction factor (or calibration factor) may be
approximately calculated with the following formula:
C
f
= ( S
new
÷ S
current
) 0.3
C
f
= Correction factor
S
new
= Specific gravity of new gas
S
current
= Specific gravity of original calibration gas
A corrected flow reading may then be calculated using the correction
factor as follows:
Corrected Flow = Flow reading X Correction Factor
For example, if the unit is calibrated for AIR but the user wants to
measure the flow of Carbon Dioxide (CO
2
) with a specific gravity of 1.517
the flow reading correction factor would be calculated as follows:
S
new
= Specific gravity of CO
2
= 1.517
S
current
= Specific gravity of Air = 1.000
C
f
= (S
current
÷ S
new
) 0.3
C
f
= ( 1.000 ÷ 1.517 ) 0.3
C
f
= 0.88