Rotary pump with thrust bearings

Abstract

A rotary blood pump includes a casing defining a pumping chamber. The pumping chamber has a blood inlet and a tangential blood outlet. One or more motor stators are provided outside of the pumping chamber. A rotatable impeller is within the pumping chamber and is adapted to cause blood entering the pumping chamber to move to the blood outlet. The impeller has one or more magnetic regions. The impeller is radially constrained in rotation by magnetic coupling to one or more motor stators and is axially constrained in rotation by one or more hydrodynamic thrust bearing surfaces on the impeller.

1 . A rotor for use in a rotary pump comprising:
 a plurality of axially raised bodies spaced apart to define fluid flow paths therebetween, and an upwardly facing common surface extending radially inwardly from each of the raised bodies, wherein the raised bodies and the fluid flow paths define a substantially circular periphery, each fluid flow path having a downwardly sloping bottom surface extending from the common surface to a respective fluid exit at the periphery, wherein the downwardly sloping bottom surfaces of the fluid flow paths are separated from one another by a portion of the common surface.   
     
     
         2 . The rotor as claimed in  claim 1 , wherein the common surface is recessed axially relative to each of the raised bodies. 
     
     
         3 . The rotor as claimed in  claim 1 , wherein the common surface is a planar surface. 
     
     
         4 . The rotor as claimed in  claim 2 , wherein the axially recessed common surface is bounded by substantially planar axially extending surfaces of the raised bodies. 
     
     
         5 . The rotor as claimed in  claim 4 , wherein the axially extending surfaces of the raised bodies define a polygon section of the rotor. 
     
     
         6 . The rotor as claimed in  claim 3 , wherein each of the fluid flow paths has parallel sidewalls perpendicular to the sidewalls of the flow path which is adjacent to such flow path, wherein the surface area of a leading sidewall of each flow path is less than the surface area of the opposite sidewall of the flow path. 
     
     
         7 . The rotor as claimed in  claim 1 , wherein the raised bodies comprise magnetic poles. 
     
     
         8 . The rotor as claimed in  claim 7 , wherein each raised body has a cavity and a magnet disposed within the cavity. 
     
     
         9 . The rotor as claimed in  claim 1 , wherein each of the raised bodies has an upper surface area which defines an inclined region extending axially upwardly, such that in a state in which the rotor is operated within a pumping chamber, the upper surface area of each raised body faces an interior upper wall surface of the pumping chamber to increase fluid pressure on the rotor beneath the upper wall surface in an axial direction of the rotor when the rotor is rotating. 
     
     
         10 . A rotary pump, comprising:
 a pumping chamber having an upper wall surface; and   a plurality of axially raised bodies spaced apart to define fluid flow paths therebetween, and an upwardly facing common surface extending radially inwardly from each of the raised bodies, wherein the raised bodies and the fluid flow paths define a substantially circular periphery, each fluid flow path having a downwardly sloping bottom surface extending from the common surface to a respective fluid exit at the periphery, wherein the downwardly sloping bottom surfaces of the fluid flow paths are separated from one another by a portion of the common surface.   
     
     
         11 . The rotary pump as claimed in  claim 10 , wherein the common surface is recessed axially relative to each of the raised bodies. 
     
     
         12 . The rotary pump as claimed in  claim 10 , wherein the common surface is a planar surface. 
     
     
         13 . The rotary pump as claimed in  claim 11 , wherein the axially recessed common surface is bounded by substantially planar axially extending surfaces of the raised bodies. 
     
     
         14 . The rotary pump as claimed in  claim 13 , wherein the axially extending surfaces of the raised bodies define a polygon section of the rotary pump. 
     
     
         15 . The rotary pump as claimed in  claim 12 , wherein each of the fluid flow paths has parallel sidewalls perpendicular to the sidewalls of the flow path which is adjacent to such flow path, wherein the surface area of a leading sidewall of each flow path is less than the surface area of the opposite sidewall of the flow path. 
     
     
         16 . The rotary pump as claimed in  claim 10 , wherein the raised bodies comprise magnetic poles, and the pump further includes a stator, wherein the stator is configured to generate a magnetic field which interacts with the poles of the rotor to impart rotational movement of the rotor within the pumping chamber. 
     
     
         17 . The rotary pump as claimed in  claim 16 , wherein each raised body has a cavity and a magnet disposed within the cavity. 
     
     
         18 . The rotary pump comprising the rotor as claimed in  claim 10 , wherein each of the raised bodies has an upper surface area which defines an inclined region extending axially upwardly, such that in a state in which the rotor is operated within the pumping chamber, the upper surface area of each raised body faces the upper wall surface of the pumping chamber to increase fluid pressure on the rotor beneath the upper wall surface in an axial direction of the rotor when the rotor is rotating.