Calibration Procedures; Flow Calibration - Omega FMA 4000 User Manual

7.

CALIBRATION PROCEDURES

NOTE: REMOVAL OF THE FACTORY INSTALLED CALIBRATION
SEALS AND/OR ANY ADJUSTMENTS MADE TO THE METER, AS
DESCRIBED IN THIS SECTION, WILL VOID ANY CALIBRATION
WARRANTY APPLICABLE.
7.1

Flow Calibration

Omega ® Engineerings' Flow Calibration Laboratory offers professional calibration
support for Mass Flow Meters using precision calibrators under strictly controlled
conditions. NIST traceable calibrations are available. Calibrations can also be per-
formed at customers' site using available standards.
Factory calibrations are performed using NIST traceable precision volumetric cal-
ibrators incorporating liquid sealed frictionless actuators.
Generally, calibrations are performed using dry nitrogen gas. The calibration can
then be corrected to the appropriate gas desired based on relative correction [K]
factors shown in the gas factor table (see APPENDIX III). A reference gas, other
than nitrogen, may be used to better approximate the flow characteristics of cer-
tain gases. This practice is recommended when a reference gas is found with ther-
modynamic properties similar to the actual gas under consideration. The appro-
priate relative correction factor should be recalculated (see section 9).
It is standard practice to calibrate Mass Flow Meters with dry nitrogen gas at
F F
70.0 F (21.1 C), 20 psia (137.9 kPa absolute) inlet pressure and 0 psig outlet
pressure. It is best to calibrate FMA 4000 transducers to actual operating condi-
tions. Specific gas calibrations of non-toxic and non-corrosive gases are available
for specific conditions. Please contact your Omega
It is recommended that a flow calibrator be used which has at least four times bet-
ter collective accuracy than that of the Mass Flow Meter to be calibrated.
Equipment required for calibration includes: a flow calibration standard, PC with
available RS485 / RS232 communication interface, a certified high sensitivity
multi meter (for analog output calibration only), an insulated (plastic) screwdriver,
a flow regulator (for example - metering needle valve) installed upstream from the
Mass Flow Meter, and a pressure regulated source of dry filtered nitrogen gas (or
other suitable reference gas). Using Omega
nance software to simplify the calibration process is recommended.
Gas and ambient temperature, as well as inlet and outlet pressure conditions,
should be set up in accordance with actual operating conditions.
for a price quotation.
®
® supplied calibration and mainte-
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