Rotating machine using a cooling fluid supplied by a rotating seal

An electric machine with a superconductive rotor provided with a cooling circuit having rotating seals, comprising:

• a rotor mounted for rotation about its axis and having a peripheral zone of which heat is generated;
• an internal cooling circuit in said rotor enabling the circulation of a cooling fluid subjected to centrifugal force resulting from the rotating of this rotor, said circuit comprising a rotary supply pipe within the axis of the rotor, first pipes extending radially outward from the rotary supply pipe and allowing the fluid to move away from said axis to reach the rotor peripheral zone, second pipes extending longitudinally within said rotor peripheral zone having a first end connected to respective first pipes and allowing the fluid coming from this descending pipe to circulate in the peripheral zone, collecting the heat generated in this zone;
• outlet means for the cooling fluid which has crossed through the second pipes;
• a stationary external cooling circuit outside of said rotor comprising a stationary supply pipe, a rotating supply seal connecting said stationary supply pipe to said rotary supply pipe, and a stationary outlet pipe collecting the cooling fluid leaving the rotor;
• a cooling device connected in series between the stationary supply and outlet pipes for cooling the cooling fluid;
• means for circulating the cooling fluid through said cooling device, the stationary and rotary supply pipes, the first pipes, the second pipes, said outlet means and said stationary pipe;
• said cooling fluid outlet means comprising third pipes connected to the second end of respective second pipes and extending radially to allow the cooling fluid to return towards the axis of the rotor and a rotary outlet pipe disposed along said axis and connected to the stationary outlet pipe by a rotary outlet seal coaxial with the supply seal, one of these two rotating seals forming an inner rotating seal limiting the communication between the supply and outlet pipes and the other of said rotating seals forming an outer rotating seal separating the space inside the cooling circuits from the space outside these circuits;
• said rotating inner seal being of the "bayonet" type in which the two pipes connected by the seal comprise an outer pipe and an inner pipe, the outer pipe surrounding the inner pipe extending over an axial covering length forming a radial gap between the adjacent surfaces of these two pipes, the radial gap between these adjacent surfaces being greater than 0.6 mm at least when the rotor rotates at its highest speed, so as to enable the thermosiphon effect resulting from the rotating of the rotor and from the difference in temperature of the cooling fluid between the first pipes and the third pipes to make the cooling fluid circulate in a closed loop constituted by the inner circuit and by the leakage of the inner seal through said radial gap.