A METHOD OF DESIGNING A ROTOR FOR A ROOTS-TYPE BLOWER

摘要

A method of designing rotors for a Roots blower comprising a housing having cylindrical chambers, the housing defining an outlet port (19). The blower includes meshed, lobed rotors (37,39) disposed in the chambers, each rotor including a plurality N of lobes (47,49), each lobe having first (47a,49a) and second (47b,49b) axially facing end surfaces. Each lobe has its axially facing surfaces defining a twist angle (TA), and each lobe defines a helix angle (HA). The method of designing the rotor comprises determining a maximum ideal twist angle (TAM) for the lobe as a function of the number N of lobes on the rotor, and then determining a helix angle (HA) for each lobe as a function of the maximum ideal twist angle (TAM ) and an axial length (L) between the end surfaces of the lobe.