Cooling system for a submersible electric motor

Claim 1

IN A SUBMERSIBLE MOTOR ADAPTED TO BE LOWERED IN A WELL, SAID MOTOR HAVING A CASING, A LIQUID FILLING FOR THE CASING, A STATOR STRUCTURE IN THE CASING, AND ISOLATED FROM THE LIQUID FILLING, AN END WALL AT THE UPPER END OF THE STATOR STRUCTURE, A SHAFT PROJECTING THROUGH SAID END WALL, A ROTOR STRUCTURE CARRIED BY THE SHAFT, AND COOPERABLE WITH SAID STATOR STRUCTURE, A ROTARY SEAL LOCATED AT SAID UPPER END WALL FOR ISOLATING THE LIQUID FILLING FROM THE WELL, THE COMBINATION THEREWITH OF: MEANS FORMING A PASSAGE IN THE SHAFT AND HAVING AN UPPER OPENING IN THE CASING BETWEEN THE SEAL AND THE UPPER END OF THE ROTOR STRUCTURE, SAID PASSAGE HAVING A LOWER OPENING BENEATH THE ROTOR; PUMPING MEANS HAVING AN INTAKE CONNECTED TO SAID LOWER OPENING OF SAID SHAFT; A HEAT EXCHANGER SUSPENDED FROM AND CLOSING THE LOWER END OF THE CASING AND RECEIVING THE DISCHARGE OF SAID PUMPING MEANS, SAID HEAT EXCHANGER DEFINING A HEAT EXCHANGE PATH FOR RETURN OF THE LIQUID FILLING TO THE CASING AT THE LOWER END OF SAID ROTOR STRUCTURE AT AN AREA EXTERIOR OF THE SHAFT; AND DIAPHRAGM MEANS CARRIED BY THE HEAT EXCHANGER AND EXPOSED ON OPPOSITE SIDES TO THE DISCHARGE OF SAID PUMPING