Doctoral thesis defended by Frédéric BOINEAU on December 9th 2016
This thesis focuses on developing applications for the constant-pressure gas flow meter, which is the main reference instrument for measuring very small gas flow rates; it is commonly used by France's national Metrology Laboratories. This instrument helps determine the traceability of both low absolute pressures, by means of the continuous expansion method, and helium leaks related to applications in the vacuum field. Moreover, we demonstrate herein that the constant-pressure flow meter operated at the Joint Metrology Laboratory (JML) has served to corroborate micro flow rate measurements, which is a component of the flow metering field. In addition to offering key design aspects and a metrological characterization, this thesis describes the continuous expansion study along with efforts to draw comparisons of the constant-pressure gas flow meter with the reference methods being used at JML, notably the dynamic gravimetric method.