Patent ID: 7568896
Filing Date: 2009-08-04
Classification: F04D

Abstract:
1. A pump for moving a liquid, the pump comprising an electric motor having a stator and magnetic rotor, the stator including at least one electric winding adapted, in use, to generate a rotating electromagnetic field, the rotor mounted adjacent the stator for rotation about an axis in response to the rotating electromagnetic field, the rotor and stator providing first and second spaced-apart surfaces defining a pumping passage therebetween, the pumping passage having an inlet at one axial end of the rotor and an outlet at another axial end of the rotor; and at least one helical thread disposed between the first and second surfaces and mounted to one of said surfaces, the thread when viewed in a cross section taken substantially parallel to the rotor axis having a rounded surface facing the other of said surfaces, wherein the rotor is sized relative to a selected working liquid such that, in use, the rotor in rotation is radially supported relative to the stator substantially only by a layer of the liquid maintained between the rotor and stator by rotor rotation.