초록 ▼

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)

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. A rotor designed in accordance with this method is also provided.

대표청구항 ▼

What is claimed is: 1. A method of designing a rotor for a Roots-type blower comprising a housing defining first and second transversely overlapping cylindrical chambers, said housing including a first end wall defining an inlet port, and a second end wall, said housing defining an outlet port forme

What is claimed is: 1. A method of designing a rotor for a Roots-type blower comprising a housing defining first and second transversely overlapping cylindrical chambers, said housing including a first end wall defining an inlet port, and a second end wall, said housing defining an outlet port formed at an intersection of said first and second chambers, and adjacent said second end wall; said blower including first and second meshed, lobed rotors disposed, respectively, in said first and second chambers; each rotor including a plurality N of lobes, each lobe having first and second axially facing end surfaces sealingly cooperating with said first and second end walls, respectively, and a top land sealingly cooperating with said cylindrical chambers, each lobe having its first and second axially facing end surfaces defining a twist angle, and each lobe defining a helix angle; said method of designing a rotor comprising the steps of:(a) determining a maximum ideal twist angle for said lobe as a function, partially, of said number N of lobes on said rotor, said maximum ideal twist angle being the largest possible twist angle for each rotor lobe without opening a leak path from the outlet port to the inlet port,wherein a total maximum seal time is a sum of an inlet seal time and a transfer seal time, and wherein the transfer seal time is equal to zero at the maximum ideal twist angle;(b) determining a helix angle for each lobe as a function of said twist angle and an axial length between said first and second axially facing end surfaces of said lobe; and(c) selecting a twist angle corresponding to a desired transfer seal time while keeping the total maximum seal time constant.