The measurement of deformation rate of flexible container based on constant conductance element in molecular regime

An innovative method using constant conductance element to measure the deformation rate of flexible container was proposed based on the theoretical model of dynamic micro-flow detection. The measurement system of dynamic deformation rate was built by using the semi-flexible container encapsulated with polyimide film, and a constant conductance element was installed between the flexible container and the pressure stabilizing chamber to provide a constant micro-flow rate. The dynamic differential pressure variation between the inlet and the outlet of the constant conductance element was measured and then the deformation rate of flexible container could be obtained through the iterative calculation of the measured differential pressure change over time. The results show that the deformation rate gradually decreases with the increase of differential pressure. In addition, Boyle's law was used to verify the experimental results of dynamic micro-flow detection method, and it is revealed that the measurement error is less than 11%. Finally, a standard leak element was applied to simulate the leak source of flexible container. The conductance of standard leak element and the leak rate of flexible container have been successfully predicted by using the measured deformation rate.