Vane type compressor having elliptical stator with doubly-offset rotor

A rotary compressor comprising in combination a housing defining a chamber having opposed parallel end walls and a curved outer wall, the outer wall having a reference region between inlet and outlet sides of the chamber, said inlet and outlet sides having a substantially elliptical profile having major and minor axes centered on the chamber axis, a rotor of cylindrical shape having a plurality of equally spaced radial grooves formed therein and having a shaft supporting the same for rotation in the housing, vanes profiled to fit the chamber and radially slidable in the grooves to define enclosed compartments between them, each vane having a pair of axially extending stubshafts having rollers respectively mounted thereon, roller tracks formed in the end walls of the chamber for accommodating the rollers and for guiding the vanes so that the profiled outer edges of the vanes follow the outer wall of the chamber in closely spaced engagement, means defining an inlet port on the inlet side of the chamber for aspiration of gas into a compartment and an outlet port on the outlet side for discharging gas from the compartment in the compressed state, the ports being located in the curved outer wall of the chamber and positioned to closely straddle the reference region, the eccentricity of the elliptical profile lying within the range of 15 degrees and 45 degrees, the rotor having its axis laterally offset from the chamber axis along both the major and minor axes so as to produce sealing engagement of the rotor at the reference region for sealing between the ports, and the rotor being sufficiently large so there are three positions about the circumference where the tangents to the rotor and the curved wall of the chamber are parallel to one another so that each vane undergoes but a single in and out stroke during each revolution of the rotor notwithstanding the elliptical nature of the chamber.