Optimal design and development of two-segment variable-pitch screw rotors for twin-screw vacuum pumps. (September 2022)

• Record Type: Journal Article
• Authors: Wang, Jun; Zhao, Lizhuang; Zhao, Xihao; Pan, Shiyang; Wang, Zengli; Cui, Dong; Geng, Maofei
• Is Part Of: Vacuum. Volume 203(2022)
• Publication Date: 2022-09
• Subjects: Twin-screw vacuum pump -- Two-segment variable-pitch screw rotor -- Built-in volume ratio -- Geometric performance -- Ultimate vacuum; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2022.111254
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: The built-in volume ratio of the twin-screw vacuum pump plays a crucial role in determining its applications. The screw rotor with larger built-in volume ratio has lower power consumption and lower discharge temperature, which is beneficial to obtain a higher ultimate vacuum. In order to improve the built-in volume ratio of screw rotors, and then develop a twin-screw vacuum pump with high ultimate vacuum, this paper presented a two-segment variable-pitch screw rotor generated by sweeping a constant cross-sectional profile along helixes. Effects of geometric parameters including the radius ratio and central angle on the rotor structure, area utilization and pumping speed of the proposed variable-pitch screw rotor were analyzed. Consequently, a pair of intermeshing two-segment variable-pitch screw rotors were optimized and manufactured, and a prototype of a twin-screw vacuum pump was developed. The performance of the proposed variable-pitch screw rotor was verified by the performance experiment of the developed prototype. Results show that the proposed two-segment variable-pitch screw rotors exhibits many distinct advantages of high ultimate vacuum, easy to process, and low noise and vibration; and its ultimate vacuum can quickly reach 0.1Pa. The developed screw rotors are of great significance for improving the performance and application of the twin-screw vacuum pump. Highlights: Novel two-segment variable-pitch screw rotors were proposed. Effects of geometric parameters on the proposed rotors were obtained. The proposed screw rotors were optimized and manufactured. The performance of the screw rotor was verified by the experiment.