Rotor Assembly for Rotary Compressor

Abstract

A compressor having a rotor assembly within which a rotor is rotated on an eccentric shaft in a sealed chamber. Two or more intake ports are provided that open into the sealed chamber and two or more exhaust ports are provided with one way valves, to permit compressed gas to exit the sealed chamber. The geometry of the rotor and sealed chamber and eccentric drive are such that apices of the rotor remain in contact with a peripheral wall of the sealed chamber as the rotor rotates and apex seals are provided on the apices of the rotor to prevent leakage of the gas around the apices of the rotor. In a preferred embodiment the rotor is a multi-lobed rotor orbiting within a trochoidal chamber.

What is claimed is: 
     
         1 . A compressor comprising a rotor assembly within which a multi-lobed rotor is rotated on an eccentric shaft in a sealed trochoidal chamber, two or more intake ports are provided that open into the sealed chamber, two or more exhaust ports are provided with one way valves, to permit compressed gas to exit the sealed chamber, the geometry of the rotor and sealed chamber and eccentric drive are such that the ratio of the distance between the centre of the rotor and the apices of the rotor to the amount of eccentricity in the eccentric shaft (R/e ratio) is about 10:1 and apices of the rotor remain in contact with a peripheral wall of the sealed chamber as the rotor rotates and apex seals are provided on the apices of the rotor to prevent leakage of the gas around the apices of the rotor. 
     
     
         2 . A compressor according to  claim 1 , wherein the rotor is a three lobed rotor journalled on a shaft and having a ring gear driven by timing pinion, the gear ratio of the ring gear to the timing pinion being three to one. 
     
     
         3 . A compressor according to  claim 1 , wherein the apex seals are compression seals that remain in contact with the peripheral wall of the sealed chamber as the rotor rotates. 
     
     
         4 . A compressor according to  claim 3 , wherein the apex seals have an apex seal spring to maintain the apex seal in contact with the peripheral wall of the sealed chamber as the rotor rotates. 
     
     
         5 . A compressor according to  claim 1 , wherein the rotor assembly comprises a back plate, rotor housing and front plate wherein an inner peripheral wall of the rotor housing together with inner surfaces of the back plate and front plate define the sealed chamber within which the rotor is rotated on an eccentric shaft. 
     
     
         6 . A compressor according to  claim 5 , wherein there are two intake ports and two exhaust ports. 
     
     
         7 . A compressor according to  claim 6 , wherein the two intake ports are provided in the back plate. 
     
     
         8 . A compressor according to  claim 6 , wherein the two intake ports are provided in the front plate. 
     
     
         9 . A compressor according to  claim 5 , further comprising one or more intake ports provided in the back plate and one or more intake ports in the front plate, all of said intake ports opening into the sealed chamber and two exhaust ports provided in the rotor housing. 
     
     
         10 . A compressor according to  claim 1 , further comprising a rotary drive enclosed by a sealed casing and orbiting the rotor, a driven element of a magnetic coupling in driving connection with the rotary drive and orbiting the rotor, the driven element enclosed by the sealed casing and including at least one magnet, a driving element of the magnetic coupling outside of the casing in close proximity to the driven element, and an arrangement for rotating the driving element. 
     
     
         11 . A compressor according to  claim 10 , wherein the arrangement for rotating the driving element includes an electric motor. 
     
     
         12 . A compressor according to  claim 11 , wherein the magnet includes a plurality of electromagnets. 
     
     
         13 . A compressor according to  claim 12 , wherein the driving element includes a plurality of electromagnets. 
     
     
         14 . A compressor according to  claim 1 , further comprising a rear vector plate to cap the back of the rotor assembly. 
     
     
         15 . A compressor according to  claim 14 , further comprising a seal retention plate to cap the front of the rotor assembly and having an opening through which the shaft extends to permit an end of the shaft to be connected to a direct drive. 
     
     
         16 . A compressor according to  claim 15 , further comprising a seal around that portion of the shaft passing through the opening in the seal retention plate.