Method and means for preventing cavitation in hydraulic piston and vane pumps

Claim 1

IN A HYDRAULIC FLUID ENERGY TRANSLATING DEVICE OF THE POSITIVE DISPLACEMENT TYPE HAVING AN INLET SIDE, AN OUTLET SIDE, A PLURALITY OF FLUID TRANSPORTING CAVITIES AND MEANS FOR ROTATING SAID CAVITIES ABOUT AN AXIS IN A PLANE, THE IMPROVEMENT WHICH COMPRISES A DYNAMIC PREROTATIOPN UNIT DISPOSED ON THE INLET SIDE OF SAID FLUID ENERGY TRANSLATING DEVICE, SAID DYNAMIC PREROTATION UNIT COMPRISING A HOUSING INCLUDING A CHAMBER IN COMMUNICATION WITH SAID CAVITIES, A HOLLOW ROTATOR HAVING RADIALLY EXTENDING VANES, MOUNTED WITHIN SAID HOUSING, AND MEANS FOR ROTATING SAID ROTATOR ABOUT THE AXIS OF ROTATION OF SAID CAVITIES AND IN THE DIRECTION OF ROTATION OF SAID FLUID TRANSPORTING CAVITIES, SAID FLUID FLOWING THROUGH SAID ROTATOR, SAID ROTATOR BEING EFFECTIVE TO IMPART A ROTATIONAL COMPONENT TO THE VELOCITY OF SAID FLUID, SAID ROTATIONAL COMPONENT BEING IN THE SAME DIRECTION AS THE DIRECTION OF ROTATION OF SAID FLUID TRANSPORTING CAVITIES, SAID HOUSING BEING CONFIGURATED TO ESTABLISH AXIAL COMMUNICATION BETWEEN SAID ROTOR AND SAID FLUID TRANSPORTING CAVITIES, WHEREBY FLUID FLOWING THROUGH SAID ROTATOR ENTERS SAID CAVITIES WITH SUBSTANTAILLY THE SAME VELOCITY BY SAID ROTATOR.