Rotary pump with hydrodynamically suspended impeller

Abstract

This invention relates to rotary pumps adapted, but not exclusively, for use as artificial hearts or ventricular assist devices and, in particular, discloses in preferred forms a seal-less shaft-less pump featuring open or closed (shrouded) impeller blades with the edges of the blades used as hydrodynamic thrust bearings and with electromagnetic torque provided by the interaction between magnets embedded in the blades and a rotating current pattern generated in coils fixed relative to the pump housing.

1 . (canceled)  
   
   
       2 . A rotary blood pump for use in a heart assist device, said pump having an impeller suspended within a pump housing by hydrodynamic thrust forces generated by relative movement of said impeller with respect to and within said pump housing; and wherein at least one of said impeller and said housing includes at least a first deformed surface lying on at least part of a first face which, in use, moves relative to respective facing surfaces on the other of said impeller and said housing thereby to form a relatively moving surface pair which generates relative hydrodynamic thrust between said impeller and said housing which includes everywhere a localized thrust component substantially and everywhere normal to said first deformed surface.  
   
   
       3 . The pump of  claim 2 , wherein the pump includes a hydrodynamic bearing.  
   
   
       4 . The pump of  claim 2 , wherein said pump includes radial and axial direction control and said radial and axial direction control is provided by the inclusion of one set of surfaces on said pump angled with respect to the rotational axis of the impeller.  
   
   
       5 . The pump of  claim 2 , wherein said impeller includes blades which are tapered or non-planar, so that a thrust is created between edges of said blades and the pump housing during relative movement therebetween.  
   
   
       6 . The blood pump of  claim 2  wherein said pump is of centrifugal type or mixed flow configuration, wherein said impeller includes blades which form gaps in said impeller, and wherein said gaps open on both front and back faces of the impeller.  
   
   
       7 . The pump of  claim 6 , wherein the front face of the pump housing is generally conical shaped, to allow said thrust forces to be generated generally perpendicular to an inner conical surface of the housing and wherein said thrust forces have a radial component to resist radial displacement of the impeller axis.  
   
   
       8 . The pump of  claim 2 , wherein said first deformed surface and is integral to at least one surface of said impeller.  
   
   
       9 . A rotary blood pump for assisting blood circulation comprising: a plastic, metal or ceramic housing; a hydrodynamically suspended impeller wherein said impeller, in use, is magnetically urged to rotate; and at least one stator assembly.  
   
   
       10 . The pump of  claim 9 , wherein at least a portion of said pump is coated with a biocompatible film.  
   
   
       11 . The pump of  claim 10 , wherein said film includes titanium nitride or carbon.  
   
   
       12 . The pump of  claim 9 , wherein said impeller includes at least one blade.  
   
   
       13 . An implantable rotary blood pump comprising: a housing; an impeller where said impeller, in use, is magnetically urged to rotate; a hydrodynamic bearing formed by the cooperation of a surface of said impeller and said housing; and at least one stator assembly.  
   
   
       14 . A rotary blood pump comprising: a housing, at least one stator assembly, and a hydrodynamically suspended impeller; wherein said impeller carries at least one permanent magnet; and wherein said magnet produces an axis of magnetism and wherein said axis of magnetism is offset at an angle extending away from the axis of rotation of said impeller.  
   
   
       15 . A rotary blood pump comprising: a housing; a hydrodynamically suspended impeller wherein said impeller, in use, is magnetically urged to rotate; at least one stator assembly and wherein said stator assembly and impeller cooperate to form a three phase motor.  
   
   
       16 . A rotary blood pump comprising: a housing, a hydrodynamically suspended impeller wherein said impeller, in use, is magnetically urged to rotate, at least two stator assemblies wherein at least a portion of one said stator assembly is aligned at generally 45° to an axis of rotation of the said impeller.  
   
   
       17 . A rotary blood pump comprising: a housing; a hydrodynamically suspended impeller wherein said impeller is magnetically urged to rotate; and at least one stator assembly.  
   
   
       18 . The pump of  claim 17  wherein said housing is polymeric.  
   
   
       19 . The pump of  claim 17  wherein movement of said impeller generates axial and/or radial thrust forces.  
   
   
       20 . The pump of  claim 17  wherein said impeller includes an integral hydrodynamic bearing surface.  
   
   
       21 . The pump of  claim 17 , wherein said pump is shaftless.  
   
   
       22 . The pump of  claim 21 , wherein said impeller includes at least two blades.  
   
   
       23 . The pump of  claim 22 , wherein said blades are supported by at least one support cone.  
   
   
       24 . The pump of  claim 23 , wherein said support cone generates a partial bearing means by the generation of hydrodynamic thrust forces.