Construction and simulation of novel asymmetrical scroll wraps for scroll vacuum pumps

Abstract

The existing asynchronous suction scroll vacuum pump with only one suction port has higher area utilization ratio than that of the existing synchronous suction scroll vacuum pump with two suction ports, but its built-in volume ratios of two groups of working chambers are not equal, which leads to the gas mixing at different pressures at the end of the compression process, and creates irreversible losses. In order to solve this problem, an asymmetrical twin-circular arc modified method was proposed in this study; and then a new type of asymmetrical twin-circular arc modified wrap (ACMW) with only one suction port, whose built-in volume ratios of two groups of working chambers are equal, was constructed. In addition, influences of its geometric parameters on the working performance of the scroll vacuum pump were studied, and 3D numerical simulations of its working process were conducted and compared. The study results demonstrate that wrap of the proposed orbiting scroll becomes thicker while wrap of the proposed fixed scroll is gradually thinner, as offset distance δ increases. The novel ACMW will play an important role in improving the working performance of the scroll vacuum pumps.