Patent ID: 6866625
Filing Date: 2005-03-15
Classification: A61M,Y10S

Abstract:
1. A rotary blood pump for use in a heart assist device, the pump comprising: an impeller an even number of blades and generally circumferentially extending struts interconnecting the blades at an outer periphery of the impeller; and a pump housing wherein the impeller is suspended in use within the pump housing exclusively by hydrodynamic thrust forces generated by relative movement of the impeller with respect to and within the pump housing; and wherein at least one of the impeller and the pump housing includes at least a first deformed surface lying on at least part of a first face and a second deformed surface lying on at least a part of a second face which, in use, move relative to respective facing surfaces on the other of the at least one of the impeller and the pump housing thereby to form at least two relatively moving surface pairs which generate relative hydrodynamic thrust between the impeller and the pump housing which includes everywhere a localized thrust component substantially and everywhere normal to the plane of movement of the first deformed surface and the second deformed surface with respect to the facing surfaces; and wherein the combined effect of the localized normal forces generated on the surfaces of the impeller is to produce resistive forces against movement in three translational and two rotational degrees of freedom.