Low cost capillary flow meter

This article introduces a project and some specifications of the capillary flow meter. The functioning of the presented flow meter is based on the measurement of pressure drop caused by the gas flowing through the capillary. The article includes in detail a description of the calibration process of the above-mentioned measuring device and presents its basic specifications and capabilities. The measurement results are barometric and temperature compensated. The upper range boundary of the presented device amounts to 45 μmol/s and the measuring error accounts for 0.3% of the full measuring range of the meter. The costs of material used for constructing the prototype of the capillary flow meter did not exceed US$ 30.