Experimental Study of the Pumping Mechanism of a Dry-Scroll Vacuum Pump

The validity of the theory concerning the pumping performance of a dry-scroll vacuum pump proposed by the authors has been examined using the following three experiments, (1) the 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) the measurement of local pressure in the outermost pocket, (3) the measurement of the pumping speed throughout the working pressure range. Comparison of the experimental results with the theoretical predictions confirms the validity of the theoretical treatment.