Axial flow blood pump with hollow rotor

Abstract

An axial flow blood pump includes a housing and a hollow rotor in the housing. The housing has an entrance end, an exit end, and a pump axis. The rotor has at least one spiral conveying rotor blade arranged on an inner surface of the rotor. The spiral conveying rotor blade extends toward a center of the rotor while leaving the center of the rotor open to define a central axial passage for a blood flow. The spiral conveying rotor blade has a pitch and a height that vary along the pump axis.

What is claimed is: 
     
         1 . An axial flow blood pump, comprising:
 a housing having an entrance end, an exit end, and a pump axis; and   a hollow rotor in the housing;   wherein   the rotor has at least one spiral conveying rotor blade arranged on an inner surface of the rotor, the spiral conveying rotor blade extending toward a center of the rotor while leaving the center of the rotor open to define a central axial passage for a blood flow; and   the spiral conveying rotor blade has a pitch and a height that vary along the pump axis.   
     
     
         2 . An axial flow blood pump according to  claim 1 , wherein the pitch of the spiral conveying rotor blade increases along the pump axis from the entrance end to the exit end. 
     
     
         3 . An axial flow blood pump according to  claim 1 , wherein the pitch of the spiral conveying rotor blade decreases along the pump axis from the entrance end to the exit end. 
     
     
         4 . An axial flow blood pump according to  claim 1 , wherein the height of the spiral conveying rotor blade increases along the pump axis from the entrance end to the exit end, so as to decrease a diameter of the central axial passage within the spiral conveying rotor blade in a flow direction from the entrance end to the exit end. 
     
     
         5 . An axial flow blood pump according to  claim 1 , wherein the height of the spiral conveying rotor blade decreases along the pump axis from the entrance end to the exit end, so as to increase a diameter of the central axial passage within the spiral conveying rotor blade in a flow direction from the entrance end to the exit end. 
     
     
         6 . An axial flow blood pump according to  claim 1 , wherein the hollow rotor has rifling on an outer surface thereof that faces the housing across a gap between the hollow rotor and the housing. 
     
     
         7 . An axial flow blood pump according to  claim 1 , wherein the at least one spiral conveying rotor blade includes a plurality of spiral conveying rotor blades which are axially displaced relative to each other. 
     
     
         8 . An axial flow blood pump according to  claim 1 , wherein the at least one spiral conveying rotor blade includes a plurality of spiral conveying rotor blades which are angularly displaced relative to each other. 
     
     
         9 . An axial flow blood pump according to  claim 1 , further comprising:
 a flow straightener comprising at least one vane which is shaped to straighten a blood flow entering the hollow rotor.   
     
     
         10 . An axial flow blood pump according to  claim 1 , further comprising:
 a diffuser which is shaped for re-laminarization of a blood flow exiting the hollow rotor.   
     
     
         11 . An axial flow blood pump according to  claim 10 , wherein the diffuser comprises at least one spiral vane. 
     
     
         12 . An axial flow blood pump according to  claim 1 , wherein a profile of the spiral conveying rotor blade varies along a spiral length of the rotor blade. 
     
     
         13 . An axial flow blood pump according to  claim 1 , wherein a free edge of the spiral conveying rotor blade is bent. 
     
     
         14 . An axial flow blood pump according to  claim 1 , wherein a free edge of the spiral conveying rotor blade has a notch. 
     
     
         15 . An axial flow blood pump according to  claim 1 , wherein the spiral conveying rotor blade has a torsion along the rotor blade. 
     
     
         16 . An axial flow blood pump according to  claim 1 , wherein a chord width of the spiral conveying rotor blade varies along the rotor blade. 
     
     
         17 . An axial flow blood pump according to  claim 1 , wherein the spiral conveying rotor blade contains at least one hole or slit. 
     
     
         18 . An axial flow blood pump according to  claim 1 , wherein a surface of the spiral conveying rotor blade includes ripples. 
     
     
         19 . An axial flow blood pump, comprising:
 a housing having an entrance end, an exit end, and a pump axis;   a hollow rotor in the housing; and   a diffuser disposed downstream of the hollow rotor in a flow direction from the entrance end to the exit end;   wherein   the diffuser comprises at least one spiral vane stationary relative to the housing;   the rotor has at least one spiral conveying rotor blade arranged on an inner surface of the rotor, the spiral conveying rotor blade extending toward a center of the rotor while leaving the center of the rotor open to define a central axial passage for a blood flow; and   the spiral conveying rotor blade has at least one of a pitch or a height that varies along the pump axis.   
     
     
         20 . An axial flow blood pump, comprising:
 a housing having an entrance end, an exit end, and a pump axis;   a hollow rotor in the housing;   a diffuser disposed downstream of the hollow rotor in a flow direction from the entrance end to the exit end;   a flow straightener disposed upstream of the hollow rotor in the flow direction;   at least one bearing rotatably supporting the hollow rotor inside the housing; and   an electric motor configured to drive the hollow rotor;   wherein   each of the flow straightener and the diffuser comprises at least one vane stationary relative to the housing;   the rotor has at least one spiral conveying rotor blade arranged on an inner surface of the rotor, the spiral conveying rotor blade extending toward a center of the rotor while leaving the center of the rotor open to define a central axial passage for a blood flow; and   the spiral conveying rotor blade has a pitch and a height that vary along the pump axis.   
     
     
         21 . An axial flow blood pump according to  claim 20 , wherein the at least one bearing comprises a magnetic bearing or an electromagnetic bearing.