Mesurement of Molecular Flow Conductance Based on Dynamic Differential Pressure Attenuation Method

In this paper,a new technique to measure the conductance based on dynamic differential pressure method is introduced.The constant conductance element is made of anodic porous alumina(AAO)as template.AAO was used to connect two vary pressure containers,the conductance can be measured by monitoring pressure attenuation and least square function fitting method.This experiment has researched gas conductance of nitrogen,helium and argon respectively.As the result,AAO has a constant flow conductance under a standard atmosphere pressure,and it doesn't change with the inlet pressure.The test points of Helium,starting pressure of 30 000 Pa,initial pressure difference of 1 297 Pa and measurement time 60 s were evaluated for uncertainty,and the relative synthetic standard uncertainty was 13%.Through analysis of the evaluation process,it was found that the uncertainty of measurement points increased sharply with the increase of measurement time.The measuring range of the conductance measurement system is 1×10^-4~1×10^-7m³/s,and the conductance measurement system has simple and precise characteristics.