Vane type compressor employing elliptical-circular profile

A rotary compressor comprising in combination a housing defining a chamber having opposed parallel end walls and a curved smoothly continuous outer wall centered about a chamber axis, the outer wall having a reference region defining inlet and outlet sides of the chamber, a rotor of cylindrical shape having a plurality of equally spaced radial grooves formed therein and having a shaft for 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 outer edges of the vanes follow in closely spaced proximity the outer wall of the chamber, 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 positioned to closely straddle the reference region, the rotor having its axis laterally offset from the chamber axis so as to produce engagement of the rotor at the reference region for sealing between the ports, the curved wall of the chamber on the inlet side being of substantially elliptical profile with the major axis of the ellipse generally centered on the inlet side and with the inlet port extending to a point of cut-off short of the major axis while the curved wall on the outlet side is substantially circular in profile so that gas entering the inlet port is charged in a compartment between a pair of vanes at the major elliptical axis and progressively compressed over an arc of compression greater than about 180 degrees.