Masaru Tsuchiya

Experimental verification of theory for the pumping mechanism of a dry-scroll vacuum pump

Abstract The ultimate pressure predicted by the theory that the authors have proposed agrees closely with the values from an actual machine at the rated speed, but shows smaller values than the actual machine for lower orbiting speeds as compared to the rated speed. In order to clarify this contradiction and examine the validity of the theory, the following three experiments were performed: (1) separation of the direct effect of orbiting speed on the ultimate pressure from the effect of clearance change with temperature change accompanying a change in orbiting speed, (2) measurement of the pressure inside the pump and (3) measurement of the pumping speed throughout the working pressure range. The validity of the theory was confirmed by a comparison of the theoretical predictions with the measurements.