Two-stage rotary compressor

In a two-stage, double acting compressor:

• (a) a casing having opposite open ends;
• (b) two first-stage head assemblies closing each end of said casing, said each assembly including a pair of separate chambers and an inclined plane surface facing the interior of the casing, said surface including inlet and outlet ports communicating respectively with the pair of said chambers;
• said two heads being oriented so that their inclined plane surfaces are perfectly parallel to each other;
• (c) a longitudinally extending center boom mounted centrally within said casing and being rigidly held by one of the said first stage heads;
• said boom having:
• a hollow section defining two gas collecting sectors, each equipped with two ports;
• a gas passage portion equipped with a discharge port;
• two bearing seats;
• (d) a rotor concentrically mounted in said boom, said rotor consisting of:
• (i) a hollow cylindrical core open at one end;
• bearings located within its bore;
• a drive shaft connected to the closed end;
• (ii) two cylindrical sleeves concentrically surrounding the two ends of said core to define therewith two annular spaces;
• (iii) two annular walls joining said sleeves, and said core each said annular wall having on one side thereof, a frusto-conical surface;
• each said wall having circular openings therethrough of two alternating different diameters with their centers on a same circle;
• (iv) hollow cylinders longitudinally extending between said walls, said cylinders having one large open end in axial registry with said large circular opening in said wall, the opposing end having a smaller circular opening in axial registry with said smaller circular opening in said opposing wall;
• the cylindrical bore of said cylinders having a diameter greater than the width of said spaces;
• each cylinder having a port adapted to come in cyclic registry over said ports on the corresponding gas collecting sector on said boom;
• (e) cylindrical piston-vane means rotatably and axially displaceable within the bore of each said cylinders, each said piston-vane means including two coaxial adjoining bars of different outside diameters, the larger bar being substantially equal to the inside diameter of the cylindrical bore and the smaller bar traversing said smaller opening at the end of said cylinder;
• said bars having free plane ends parallel to each other and inclined with respect to the common longitudinal axis thereof, the other end of said larger bar being perpendicular to said axis;
• the inclined end of said larger bar remaining in substantially continuous and complete sliding contact with the inclined plane surface of its respective first-stage head, the inclined end of said smaller bar remaining in substantially continuous and complete sliding contact with the inclined plane surface of the opposite first-stage head;
• the rotation of said rotor causing a rotation of said piston-vanes around their own axis and their longitudinal displacement in said cylinders and in said annular spaces, to define first stage working chambers in said annular spaces and second stage working chambers within said cylinders;
• (f) means for transferring gas compressed in said first stage working chambers to said second working chambers.