Low Vacuum Generation and Control on BIEN Technology: Mass Flow and Dry Pumping Characteristics

Abstract

Since a clean environment and finite mass flow control on the molecular level are continuously required in current R&D fields and actual process lines, technologies on vacuum generation and control have been playing a significant role in merging a variety of technologies like Bio, Information, Environment, Energy, Space and Nano. Currently, the drive towards dry vacuum pumping has broadly occurred across a spectrum of vacuum applications, from semiconductor manufacture to industrial processing, due to its most visible advantages: it is contamination free. The integrated characteristics evaluation system for dry vacuum pumps has been established in KRISS in collaboration with several branch dry pump suppliers in Korea. The evaluation system exploits a constant volume flow meter to measure mass flow rates real-timely in standard level, and facilitates the evaluation of spatially averaged sound power levels using a semi-anechoic chamber. New and overhauled roots, claw, classical screw, and scroll type pumps supplied from the manufacturers have been evaluated using the evaluation system in terms of ultimate pressure, pumping speed, vibration, and sound power. We selected the mass flow measuring method with a constant chamber volume of 875 L because of its direct monitoring capability which does not allow blind mass flow rate measurements, and proved that the method allows us to measure five decades of mass flow rates from 1×10-2 to 1×103 mbar-l/s with a measurement uncertainty of ±3%, which is within the internationally accepted standards limit. In this work, we demonstrate how the integrated pump characteristics evaluation and mass flow control method have been significant in the low vacuum range of 10-4 to 103 mbar.