Fan

Claim 1

A FAN COMPRISING A ROTOR HAVING AXIALLY EXTENDING BLADES, SAID ROTOR HAVING A FLUID FLOW PERIPHERALLY OUTWARDLY THEREFROM, A CASING ABOUT SAID ROTOR INCLUDING A PAIR OF SPACED AXIALLY EXTENDING WALLS, SAID WALLS DEFINING A SUCTION CHAMBER AND A HIGH PRESSURE DISCHARGE CHAMBER CIRCUMFERENTIALLY DISPOSED ABOUT THE PERIPHERY OF THE ROTOR, SAID ROTOR HAVING ITS PERIPHERY ON THE DISCHARGE SIDE EXPOSED IN EXCESS OF 180 DEGREES, ONE OF SAID WALLS HAVING A PROJECTION ADJACENT THE PERIPHERY OF THE ROTOR AND EXTENDING IN A SMOOTH SPIRALING SURFACE OUTWARDLY AND AWAY FROM THE PERIPHERY OF THE ROTOR AND TERMINATING IN A DISCHARGE END, SAID SECOND WALL BEING A COMMON WALL BETWEEN SAID SUCTION CHAMBER AND SAID HIGH PRESSURE CHAMBER, SAID SECOND WALL BEING SHAPED AS A SMOOTH OGEE SURFACE, ONE END OF WHICH ADJACENT THE PERIPHERY OF THE ROTOR AND SAID OGEE SURFACE TERMINATING IN SAID ONE END IN A PLANE SUBSTANTIALLY TANGENTIAL TO THE PERIHERY OF THE ROTOR, AND THE SAID OGEE SURFACE TERMINATING IN A DISCHARGE END OPPOSTELY FROM THE DISCHARGE END OF SAID FIRST WALL TO DEFINE A RESTRICTED OUTLET THEREWITH FROM THE CASING, SAID TANGENTIAL PORTION OF THE OGEE SURFACE COOPERATING WITH THE FLUID THEREOVER TO DEFINE A REVERSE FLOW VORTEX ADJACENT THE PERIPHERY OF THE ROTOR AND ECCENTRICAL THERETO, SAID REVERSE FLOW VORTEX COOPERATING WITH THE FLOW FROM THE SUCTION CHAMBER TO INDUCE FLOW INTO THE PERIPHERY OF THE ROTOR.