Year
1995
Abstract
A method commonly used for determining the volume of liquids is based on the measurement of the pressure needed to maintain a steady air flow in a certain number of pipelines which debouch into the tank, above and below the surface of the liquid. From these pressures, the level of the liquid is derived, and from the level the volume is finally calculated. The complete procedure for volume determination requires several pressure measurement and weighing operations. These measurements are made in a gaseous environment (the air and the pneumatic circuit), and the weight of the gas influences to a certain extent the results of the measurements. The influence is small, but not negligible, being in the range of 1 to 3 tenths of a percent. If it is not taken into account, the results of the measurements can be biased. This report presents the theoretical analysis of the aerostatic effects, provides simple formulas for determining and correcting the possible bias, and presents the comparison between theory and experiment.