Motor construction

Claim 1

A PUMPING APPARATUS COMPRISING, A PUMP INCLUDING A PUMP CASING HAVING A PUMP INLET PASSAGE; A PUMP DISCHARGE PASSAGE; A SHAFT OPENING COMMUNICATING WITH ONE OF SAID PUMP PASSAGES AND EXTENDING TO ONE END OF THE PUMP CASING; AND IMPELLER MEANS FOR PUMPING FLUID FROM THE PUMP INLET PASSAGE TO THE PUMP DISCHARGE PASSAGE, A MOTOR UNIT HAVING A STATOR; A ROTOR; AND MOTOR CASING MEANS INCLUDING MOTOR HOUSINGS AT OPPOSITE ENDS OF THE STATOR DEFINING A CHAMBER AROUND THE ROTOR, ONE OF SAID MOTOR HOUSINGS HAVING A SHAFT OPENING COMMUNICATING WITH SAID CHAMBER AND EXTENDING TO ONE END OF THE MOTOR, MEANS ATTACHING SAID ONE OF SAID MOTOR HOUSINGS TO SAID PUMP CASING WITH THE SHAFT OPENING IN THE MOTOR HOUSING COMMUNICATING WITH THE SHAFT OPENING IN THE PUMP CASING TO FORM AN ENCLOSED SHAFT PASSAGEWAY EXTENDING FROM THE CHAMBER IN THE MOTOR TO SAID ONE OF THE PUMP PASSAGES IN THE PUMP CASING, A SHAFT CONNECTED TO SAID ROTOR AND EXTENDING THROUGH SAID ENCLOSED SHAFT PASSAGEWAY TO SAID IMPELLER MEANS FOR DRIVING THE SAME, A SHAFT SEAL INTERMEDIATE THE ENDS OF SAID SHAFT PASSAGEWAY FORMING A RUNNING SEAL AROUND THE SHAFT BETWEEN THE CHAMBER IN THE MOTOR AND SAID ONE OF SAID PUMP PASSAGES AND HAVING ONE SIDE EXPOSED TO FLUID PRESSURE IN SAID CHAMBER AND THE OTHER SIDE EXPOSED TO FLUID PRESSURE IN SAID ONE OF SAID PUMP PASSAGES, A LIQUID COMPLETELY FILLING SAID CHAMBER, SAID MOTOR CASING MEANS HAVING PRESSURE TRANSMITTING MOVABLE WALL THEREIN WITH ONE SIDE EXPOSED TO FLUID PRESSURE IN SAID CHAMBER, MEANS SEALING THE OTHER SIDE OF THE MOVABLE WALL FORM OF THE FLUID SURROUNDING THE MOTOR CASING, AND PRESSURE APPLYING PASSAGE MEANS COMMUNICATING WITH SAID OTHER SIDE OF SAID MOVABLE WALL AND WITH SAID ONE OF SAID PUMP PASSAGES TO APPLY THE PRESSURE AT THE PUMP SIDE OF THE SHAFT SEAL TO THE MOVABLE WALL FOR PRESSURIZING THE LIQUID AT THE CHAMBER SIDE OF THE SHAFT SEAL AND THEREBY MAINTAIN APPROXIMATE PRESSURE BALANCE AT OPPOSITE SIDE OF THE SHAFT SEAL.