Microwave Determination of the Volume of a Pressure Vessel

Published: December 09, 2014


Michael R. Moldover, James W. Schmidt, Keith A. Gillis, James B. Mehl, John D. Wright


Using microwave techniques that are scalable to very large volumes, we measured the interior volume of a 0.3 m3, commercially-manufactured, pressure vessel with an uncertainty of 0.05 %, as confirmed by independent, more-accurate, gas-expansion measurements. This pressure vessel (or a much larger one of a similar design) could be used as either a calibrated volume standard or as a gas source and/or a gas collector for the calibration of gas-flow meters. In addition, we determined the expansion of the vessel with temperature (dV/dT)p/V = (35.3{plus or minus}1.9)×10-6 K-1 and we estimated the pressure expansion (dV/dp)T/V = 0.9×10-3 MPa-1. The volume measurement did not require careful thermostatting; its uncertainty was dominated by imperfect modeling of the volume's shape. (The estimated uncertainties are one standard uncertainty with coverage factor k = 1 corresponding to 68 % confidence level.)
Citation: Measurement Science and Technology
Volume: 26
Pub Type: Journals


volume, pressure vessel, flow metrology, flow calibrations, microwave resonances, gas metrology
Created December 09, 2014, Updated November 10, 2018