To provide accurate determinations of volumetric flow rate and thus of total liquid volume transported over a given time period, two pressure transducers are disposed a predetermined distance apart along a conduit. Precise pressure measurement readings are generated from which volumetric flow rate can be derived with accuracy. Integration of the volumetric flow rate over time yields an improved measure of the total liquid volume that has flowed through the conduit during the respective temporal interval. The two pressure transducers are disposed along the conduit a predetermined distance apart with no obstruction or restriction in the conduit between the transducers. A controller can be used to determine the volumetric flow rate using the Hagen-Poiseuille Equation.
