Dynamic balancing method for the single-threaded, fixed-pitch screw rotor

The screw rotor is the most important component of dry screw vacuum pumps used in various industrial applications. In this paper, a method for determining the dynamic balance of the single-threaded, fixed-pitch screw rotor is proposed based on previous research. A specific structure is designed in order to meet the demand of engineering. In this structure, two cavities with identical sections are preformed on both end faces of the rotor. The two cavities have the same shape, the same symmetric location relative to each other, and the same pitch with the screw rotor. All the structural parameters of the cavities are described, and the dynamic balancing of the screw rotor is feasible by closely following the procedure. Considering the calculation method does not depend on the form of the end-face profile, it can be used with any type of screw rotor end-face profile.

► A dynamic balancing design method of the screw rotors in vacuum pumps is proposed.
► The method relies on the mass removal method and mass–radius product principle.
► The method gives a special structure with two same cavities on both end of a rotor.
► The method is suitable for any kinds of single-threaded and fixed-pitch screw rotors.