The distribution (profile) of air to a bank of cells has been shown to influence metallurgy. To facilitate setting a profile a sensor giving a continuous airflow rate signal is introduced. The principle of operation is collection of bubbles in a tube and measurement of pressure drop across a calibrated orifice as the air expels under steady state conditions. Experience with the unit is illustrated, from identifying. a malfunctioning airflow meter, to revealing interaction between cells, and demonstrating the ease in establishing a profile down a bank of 16 cells with a multi-sensor unit. (C) 2004 Elsevier Ltd. All rights reserved.