Rotary machine

Claim 1

A TWO-STAGE ROTARY COMPRESSOR OF THE HELICAL SCREW TYPE HAVING A CASING STRUCTURE COMPRISING A BARREL PORTION PROVIDING TWO ALIGNED SETS OF BARRELS FOR LOW AND HIGH PRESSURE COMPRESSION STAGES ARRANGED IN TANDEM AND IN INTERSECTING RELATION ABOUT COPLANAR AXES, EACH OF SAID SETS OF BARRELS PROVIDING AN INLET PORT LOCATED GENERALLY ON ONE AND THE SAME SIDE OF THE PLANE OF SAID AXES AND A DISCHARGE PORT LOCATED GENERALLY ON THE OTHER SIDE OF SAID PLANE, SAID DISCHARGE PORTS BEING LOCATED AT THE ADJACENT ENDS OF THE RESPECTIVE STAGES AND THE INLET PORTS BEING LOCATED AT THE ENDS OF THE RESPECTIVE STGES REMOTE FROM EACH OTHER AND SAID CASING STRUCTURE FURTHER PROVIDING TWO AXIALLY SPACED APART PARTITIONS NORMAL TO SAID AXES LOCATED BETWEEN SAID SETS OF BARRELS TO FORM END WALLS FOR THE RESPECTIVE STAGES AND A TRANSVERSELY EXTENDING TRANSFER PASSAGE THEREBETWEEN, MEANS PROVIDING SEPARATE CONNECTING PASSAGES EACH COAXIAL WITH ONE OF SAID AXES AND EXTENDING THROUGH SAID TRANSFER PASSAGE TO JOIN SAID SETS OF BARRELS, AN OUTER CASING WALL RADIALLY SPACED FROM THE BARRELS OF THE HIGH PRESSURE STAGE TO PROVIDE AN AXIALLY EXTENDING DUCT EMBRACING THE MAJOR PORTION OF THE PERIMETER OF THE HIGH PRESSURE STAGE, ONE END OF SAID DUCT BEING IN OPEN AND UNRESTRICTED COMMUNICATION WITH SAID TRANSFER PASSAGE LATERALLY TO ONE SIDE OF THE PLANE OF SAID AXES AND THE OTHER END OF SAID DUCT TERMINATING IN AN OPENING PROVIDING SAID INLET PORT FOR SAID HIGH PRESSURE STAGE AT THE END THEREOF REMOTE FROM THE LOW PRESSURE STAGE, SAID DISCHARGE PORT FOR THE LOW PRESSURE STAGE COMMUNICATING WITH SAID TRANSVERSE TRANSFER PASSAGE LATERALLY TO THE SIDE OF THE AFORESAID PLANE OPPOSITE SAID AXIALLY EXTENDING DUCT, AND MALE AND FEMALE ROTOR MEMBERS EACH COMPRISING AXIALLY SPACED ROTOR SECTIONS HAVING HELICAL LANDS AND GROOVES DISPOSED IN INTERMESHING SETS IN SAID BARRELS AND SHAFT PORTIONS EXTENDING THROUGH SAID CONNECTING PASSAGES TO CONNECT SAID SECTIONS.