Vane type compressor having elliptical stator with doubly-offset rotor

Abstract

A rotary compressor having a housing defining a chamber with a curved outer wall of substantially elliptical profile containing a rotor of cylindrical shape having a plurality of vanes profiled to fit the chamber and radially slidable in grooves in the rotor to define enclosed compartments between them. Each vane has a pair of axially extending stubshafts having rollers respectively mounted thereon. Roller tracks formed in the end walls of the chamber accommodate the rollers for guiding the vanes so that the outer edges of the vanes follow the outer wall of the chamber in closely spaced engagement. Inlet and outlet ports located in the curved outer wall of the chamber closely straddle a reference region. The rotor has its axis laterally offset from the chamber for engagement at the reference region for sealing between the ports, the rotor axis being offset toward the outlet port and being spaced along both the major and minor axes of the elliptical profile by sufficient amounts that each vane undergoes but a single in and out stroke during each revolution of the rotor notwithstanding the elliptical nature of the chamber. In the preferred construction the rollers ride in grooves having radially opposed walls formed in the respective end walls of the chamber, with the radially inward wall having substantially constant radial clearance with respect to the contained rollers thereby to determine the amount that each vane can move radially inward under starting conditions and in the face of 'slugging'.