Motor driven pump

Claim 1

A XIAL THRUST BALANCING APPARATUS FOR A MOTOR DRIVEN UNIT COMPRISING A MOTOR STATOR, A CYLINDRICAL SLEEVE INTERIORLY OF SAID MOTOR STATOR, A MOTOR ROTOR IN SAID SLEEVE, SAID ROTOR AND SAID SLEEVE HAVING A LONGITUDINAL CLEARANCE SPACE THEREBETWEEN AND DEFINING WITH SAID SLEEVE AT LEAST ONE FIXED SIZE ORIFICE, SAID MOTOR ROTOR HAVING AN OUTWARDLY EXTENDING FLUID IMPELLING PASSAGEWAY INTERMEDIATE ITS ENDS COMMUNICATING WITH SAID CLEARANCE SPACE INTERMEDIATE ITS ENDS, A SHAFT ON WHICH SAID MOTOR ROTOR IS CARRIED HAVING A FLUID PASSAGEWAY THEREIN COMMUNICATING WITH SAID OUTWARDLY EXTENDING FLUID PASSAGEWAY, A SOURCE OF FLUID CONNECTED TO SAID SHAFT PASSAGEWAY, MEMBERS CLOSEING THE END OF SAID SLEEVE THROUGH AT LEAST ONE OF WHICH SAID SHAFT EXTENDS, AN END MEMBER THROUGH WHICH SAID SHAFT EXTENDS HAVING A PORTION CARRIED THEREBY WITH RESPECT TO WHICH ONE END OF SAID ROTOR IS MOVABLE AND PROVIDING A VARIABLE ORIFICE, SAID SLEEVE AND SAID END MEMBER BOUNDING A FLUID PRESSURE BALANCING CHAMBER AT ONE END OF SAID ROTOR TO WHICH FLUID INPUT IS CONTROLLED BY SAID FIXED ORIFICE AND FLUID DISCHARGE BY SAID VARIABLE ORIFICE, THE PRESSURE IN SAID BALANCING CHAMBER CONTROLLING THE THE POSITIONING OF SAID MOTOR ROTOR AND THEREBY CONTROLLING SAID VARIABLE ORIFICE.