Implantable centrifugal blood pump with hybrid magnetic bearings

Abstract

A pump for pumping sensitive fluids, such as blood, has no mechanical contact between the impeller and any other structure.

1 . A low profile pump inlet comprising an inflow diffuser and an outflow orifice, wherein the diffuser is defined by an open, unobstructed chamber having two intersecting arcuate channels in direct, continuous fluid connection with the outflow orifice about an inner periphery of the intersecting arcuate channels, and wherein the outflow orifice is configured to direct a fluid from the diffuser into a pump. 
   
   
       2 . The low profile inlet of  claim 1  wherein the pump is a blood pump. 
   
   
       3 . The low profile pump inlet of  claim 1 , wherein the arcuate channels are symmetrical. 
   
   
       4 . The low profile pump inlet of  claim 1 , wherein the arcuate channels define a substantially cardioid flow path. 
   
   
       5 . The low profile pump inlet of  claim 1 , wherein the outflow orifice curves inwardly from the arcuate channels. 
   
   
       6 . The low profile pump inlet of  claim 1 , wherein the outflow orifice is configured to direct the fluid from the diffuser into the pump at an angle from the original flow path of the fluid. 
   
   
       7 . The low profile inlet of  claim 1 , wherein the outflow orifice is configure to direct the fluid in the pump at an angle substantially perpendicular to the original flow path of the fluid. 
   
   
       8 . The low profile pump inlet of  claim 1 , wherein the outflow orifice is annular in shape. 
   
   
       9 . The low profile pump inlet of  claim 1 , wherein the outflow orifice directs the fluid into the pump with a substantially uniform velocity. 
   
   
       10 . The low profile pump inlet of  claim 1 , wherein the outflow orifice directs the fluid into the pump with a substantially uniform velocity independent of any flow patterns upstream of the pump inlet. 
   
   
       11 . The low profile pump inlet of  claim 1 , wherein the inflow diffuser of the pump inlet is configured to direct the fluids into the outflow orifice such that the fluid enters the pump without vortex flow. 
   
   
       12 . A compact, low profile pump inlet comprising an inlet orifice and a flow turning structure wherein the inlet orifice is configured to direct fluid into the flow turning structure, and wherein the flow turning structure is configured to redirect the incoming fluid flow through an acute angle in a manner such that the incoming fluid flow swirls around the interior of the flow turning structure in a spiral configuration thereby equalizing the flow rate and pressure of fluid entering the low profile inlet resulting in a reduction of flow disturbances. 
   
   
       13 . The low profile pump inlet of  claim 12 , wherein the redirection of the incoming fluid reduces fluid stress. 
   
   
       14 . The low profile pump inlet of  claim 12 , wherein the low profile pump inlet is attached to the pump. 
   
   
       15 . The low profile pump inlet of  claim 14 , wherein the low profile pump inlet is attached to the pump in at least one of a permanent and a reversible manner. 
   
   
       16 . The low profile pump inlet of  claim 15 , wherein the profile is sufficiently shallow to allow implantation of the low profile pump inlet and attached pump into the human body as at least one of a heart assist device and a total heart replacement. 
   
   
       17 . The low profile pump inlet of  claim 16 , wherein the low profile pump inlet and the attached pump form a lightweight and compact unit suitable for at least one of short-term and long-term implantation as at least one of a ventricular assist device and a complete replacement heart in a human patient. 
   
   
       18 . The low profile pump inlet of  claim 17 , wherein the low profile pump inlet is attached to a magnetically suspended pump. 
   
   
       19 . The low profile pump inlet of  claim 18 , wherein the low profile pump inlet and the magnetically suspended pump are coated with biocompatible coating such that all blood contacting surfaces and tissue contacting surfaces of the low profile pump inlet and the magnetically suspended pump are at least one of hemocompatible and biocompatible. 
   
   
       20 . An apparatus for pumping sensitive biological fluids, comprising:
 a construct having an exterior, an interior having walls therein, at least one housing magnet disposed therein, and an axial center;   an inlet permitting passage of fluids through the construct and into the interior of the construct;   an outlet permitting passage of fluids through the construct from the interior of the construct, the outlet radially located from the axial center of the construct;   an impeller disposed within the interior of the construct and out of contact with the construct;   a magnetic system including at least one impeller magnet juxtaposed to the housing magnet, which is magnetized in a direction for suspending the impeller out of contact with the construct; and   a motor to drive the impeller and control fluid flowing through the apparatus.   
   
   
       21 . The apparatus of  claim 20 , wherein the impeller includes arcuate blades and arcuate passageways whereby fluid flow through the construct is redirected from the inlet to the outlet. 
   
   
       22 . The apparatus of  claim 21 , wherein the magnetic system comprises:
 a first construct permanent magnet disposed on a first wall of the interior of the construct;   a second construct permanent magnet disposed on a second wall, opposite the first wall, of the interior of the construct;   a first impeller permanent magnet disposed on the impeller distal to the axial center of the construct and juxtaposed with the first construct permanent magnet;   a second impeller permanent magnet disposed on the impeller distal to the axial center of the construct and juxtaposed with the second construct permanent magnet;   a first construct permanent magnet set disposed on the first wall of the interior of the construct;   a second construct permanent magnet set disposed on the second wall of the interior of the construct;   a first impeller permanent magnet set disposed on the impeller proximate to the axial center of the construct and juxtaposed with the first construct permanent magnet set; and   a second impeller permanent magnet set disposed on the impeller proximate to the axial center of the construct and juxtaposed with the second construct permanent magnet set;   wherein the arrangement provides radial stabilization and, due to angular positioning, provides a degree of translational stabilization of the impeller and the impeller is prevented from contacting the interior of the construct by magnetic fields.   
   
   
       23 . The apparatus of  claim 22 , wherein the inlet is integral with the construct exterior. 
   
   
       24 . The apparatus of  claim 22 , wherein the outlet is integral with the construct exterior. 
   
   
       25 . The apparatus of  claim 22 , wherein the outlet is radially located from the axial center of the construct.