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Calibration of Laminar Flow Meters for Process Gases

Published

Author(s)

John D. Wright, Thiago Cobu, Robert F. Berg, Michael R. Moldover

Abstract

We calibrated three models of commercially-manufactured, laminar flow meters (LFMs) at four pressures (100 kPa, 200 kPa, 300 kPa, and 400 kPa) with five gases (N2, Ar, He, CO2, and SF6) over a 10:1 flow range using NIST’s primary flow standards as references. We combined three items: (1) the calibration data acquired with N2, (2) gas-property data from NIST’s database REFPROP 9.0, and (3) a physical model for each LFM that accounts for the effects of viscosity, entrance and exit effects, gas expansion, gas non-ideality, and slip. This combination predicted the calibrations for the flow of Ar, He, CO2, and SF6 with a maximum error of 0.8% for Reynolds numbers Re
Citation
Flow Measurement and Instrumentation

Keywords

laminar flow meter, calibration, gas species, gas properties, rate of rise, dynamic flow standard, gravimetric flow standard, process gases
Created June 1, 2012, Updated February 19, 2017