Blood pump with constant blood pumping area

Abstract

The blood pump comprises a stationary housing structure and a rotative impeller. The stationary housing structure has a proximal end provided with an inlet, a distal end provided with an outlet, and an impeller housing. The rotative impeller is mounted within the stationary housing structure to circulate blood in a blood flow direction generally extending from the proximal end to the distal end. The rotative impeller also includes an impeller blade structure mounted in the impeller housing, and having a first annular face tapered in a direction opposite the blood flow direction and a second annular face downstream from the first annular face and tapered in the direction of the blood flow. The impeller housing includes a first annular face tapered in a direction opposite the blood flow direction and facing the first annular face of the impeller blade structure; and a second annular face tapered in the direction of the blood flow and facing the second annular face of the impeller blade structure, the tapered, annular faces being so shaped and dimensioned as to keep the area through which blood flows constant.

1 . A blood pump comprising: 
 a stationary housing structure having a proximal end provided with an inlet and a distal end provided with an outlet; said stationary housing structure including an impeller housing;    a rotative impeller mounted within the stationary housing structure to circulate blood in a blood flow direction generally extending from said proximal end to said distal end; said rotative impeller including an impeller blade structure mounted in said impeller housing; said impeller blade structure having a first annular face tapered in a direction opposite the blood flow direction and a second annular face downstream from said first annular face and tapered in the direction of the blood flow;    wherein a) said impeller housing includes a first annular face tapered in a direction opposite the blood flow direction and facing the first annular face of said impeller blade structure; and a second annular face tapered in the direction of the blood flow and facing said second annular face of said impeller blade structure; and b) said tapered, annular faces being so shaped and dimensioned as to keep the area through which blood flows constant.    
   
   
       2 . The blood pump as defined in  claim 1 , wherein the tapering, annular faces are frusto-conical faces.  
   
   
       3 . The blood pump as defined in  claim 1 , wherein said impeller blade structure includes an annular member having an inner cylindrical surface, said annular member being mounted on an impeller drive shaft of said rotative impeller, said drive shaft having an outer cylindrical surface configured and sized to receive said annular member.  
   
   
       4 . The blood pump as defined in  claim 2 , wherein said impeller blade structure includes at least two impeller blades mounted to said annular member, wherein said impeller blades are positioned around said first annular face of said impeller blade structure.  
   
   
       5 . The blood pump as defined in  claim 4 , wherein said at least two impeller blades have a width gradually decreasing in the direction of the blood flow.  
   
   
       6 . The blood pump as defined in  claim 1 , wherein said stationary housing structure includes at least two impeller blades mounted to said impeller housing structure, wherein said impeller blades are positioned around said second annular face of said impeller housing.  
   
   
       7 . The blood pump as defined in  claim 6 , wherein said at least two impeller blades have as width gradually increasing in the direction of the blood flow.  
   
   
       8 . The blood pump as defined in  claim 2 , wherein said impeller blade structure comprises a frusto-conical bushing mounted to said second frusto-conical face of said impeller blade structure in the vicinity of said outlet.