Screw type compressor having variable volume and adjustable compression

Claim 1

IN A FLUID PUMP DEVICE OF THE TYPE HAVING (A) A HOUSING PROVIDED WITH INTERSECTING CYLINDRICAL ROTOR CHAMBERS AND SUCTION AND DISCHARGE PORTS ARRANGED DIAGONALLY OPPOSITE EACH OTHER IN THE ROTOR CHAMBER WALLS NEAR THE ENDS OF SAID HOUSING, AND (B) A PLURALITY OF COMPLEMENTARY HELICALLY THREADED ROTORS ROTATABLY SUPPORTED WITHIN SAID ROTOR CHAMBERS AND COOPERATING WITH EACH OTHER AND THE CHAMBER WALLS TO FORM POCKETS AT THE SUCTION END OF THE ROTORS FOR RECEIVING FLUID THROUGH SAID SUCTION PORT, TO ADVANCE SAID POCKETS AND THE FLUID THEREIN AXIALLY ALONG THE ROTORS AND TO DISCHARGE THE FLUID FROM SAID POCKETS THROUGH SAID DISCHARGE PORT AS SAID ROTORS REVOLVE ABOUT THE AXIS THEREOF, THE IMPROVEMENT WHICH COMPRISES: (1) A SUBSTANTIALLY BARREL-SHAPED OUTER WALL FOR SAID HOUSING SURROUNDING AND SPACED FROM THE WALLS OF SAID ROTOR CHAMBERS, SAID OUTER WALL BEING CURVED BOTH CIRCUMFERENTIALLY AND LONGITUDINALLY AND HAVING ITS MAXIMUM DIAMETER AT A POINT SUBSTANTIALLY MIDWAY BETWEEN THE ENDS OF SAID HOUSING, (2) RADIALLY EXTENDING STRENGTHENING MEMBERS RIGIDLY CONNECTING SAID ROTOR CHAMBER WALLS TO SAID BARRELSHAPED OUTER WALL, (3) PORTIONS OF SAID ROTOR CHAMBER WALLS BEING CUT AWAY AND EXTENDED OUTWARDLY AWAY FROM THE ROTOR AXES TO FORM THE AXIALLY EXTENDING SIDE WALLS OF A VALVE CHAMBER HOUSED WITHIN SAID BARREL-SHAPED OUTER WALL AND IN COMMUNICATION WITH SAID ROTOR CHAMBERS, (4) RADIALLY EXTENDING WALLS FORMED INTEGRALLY WITH SAID BARREL-SHAPED OUTER WALL AND CLOSING THE END OF SAID VALVE CHAMBER, AND (5) VALVE MEANS IN SAID VALVE CHAMBER MOVABLE RADIALLY TOWARD AND AWAY FROM THE ROTORS FOR CONTROLLING THE VOLUME AND INTERNAL COMPRESSION OF THE FLUID DISCHARGED FROM SAID POCKETS THROUGH SAID DISCHARGE PORT.