Measurement of the effective pressure distribution in axial direction in a dynamic vacuum system

In this paper, a theoretical analysis of pressure distribution along the axial direction in a dynamic vacuum system with an oil diffusion pump is presented. Theoretical relationships between the measured pressure and different orientations of the gauge openings were derived by taking into account the gas beaming effect inside a test dome that is connected to an oil diffusion pump of the same diameter. A precise experimental study to verify the theoretical relationships between the measured pressures and the three orientations of the tubulated gauge was carried out using a 104‐mm‐diam test dome connected on top of an oil diffusion pump of the same diameter. Experimental results obtained on the pressure distribution in the axial direction at four tubulated gauge positions are presented and discussed.