Design and Analysis of a Rotor Profile for Roots Vacuum Pumps with an Elliptical Waist
As a core component of Roots vacuum pump,the rotor has an important influence on the performance,and the design of rotor profile is critical to design rotor.In this study,the rotor profile is designed with the waist as the elliptical line,and its profile inside the pitch circle is composed of elliptical lines,while the profile outside the pitch circle is composed of the conjugate curves of elliptical lines.Firstly,the elliptical line located at the waist and its meshing angle are determined.Then,based on the meshing relationship between the two rotors,the conjugate curve of the profile line located outside the pitch circle is solved to obtain total rotor profile.Finally,the rotor of the Roots vacuum pump with a pumping speed of 70 L/s is designed,and the relationship of rotor volume utilization with independent variable parameters is analyzed.This profile has a significant advantage in the volume utilization rate that can be greater than 50%,compared to the rotor profile with the elliptical line at the top.