ASME MFC-21.1 - Measurement of Gas Flow by Means of Capillary Tube Thermal Mass Flowmeters and Mass Flow Controllers MFC-21.1 - 2015

Capillary tube thermal mass flowmeters (MFMs) and mass flow controllers (MFCs) comprise a family of instruments for the measurement and control of the mass flow rate of gases flowing through closed conduits. This Standard covers the capillary tube type of thermal MFM. A companion standard, ASME MFC-21.2, Measurement of Fluid Flow by Means of Thermal Dispersion Mass Flowmeters, covers the other most commonly used type of thermal MFM. Both types of instruments measure the mass flow rate of gases by means of a heated element in contact with the flowing gas, and in both types, the composition of the gas must be known.