Abstract: A magnetically coupled centrifugal pump comprising a pump housing containing a pumping chamber and having an inlet and an outlet, a shaft mounted in the pump housing for rotation, a pump impeller attached to the forward end of the shaft for rotation with the shaft in the pumping chamber and a first magnet attached to the rear end of the shaft, the first magnet adapted to be magnetically coupled to a second magnet rotated by a rotary driving device, the shaft being mounted in at least two bearings spaced from each other along the length of the shaft and located between the impeller and the first magnet, a shell surrounding the shaft bearings and first magnet to seal the pump from the exterior and prevent the pumped fluid from leaking, the shell being located between the two magnets and being able to transmit magnet forces between the two magnets for magnetically coupling the two magnets together, the pump housing containing a passage for conducting cooling fluid from the discharge of the pump impeller to the b