Rotary Pump with Hydrodynamically Suspended Impeller

Abstract

A pump assembly 1, 33, 200 adapted for continuous flow pumping of blood. In a particular from the pump 1, 200 is a centrifugal pump wherein the impeller 100, 204 is entirely sealed within the pump housing 2, 201 and is exclusively hydrodynamically suspended therein as the impeller rotates within the fluid 105 urged by electromagnetic means external to the pump cavity 106, 203. Hydrodynamic suspension is assisted by the impeller 100, 204 having deformities therein such as blades 8 with surfaces tapered from the leading edges 102, 223 to the trailing edges 103, 224 of bottom and top edges 221, 222 thereof.

1 - 18 . (canceled) 
     
     
         19 . A heart assist device, comprising:
 an impeller suspended in use within a pump housing by at least one of magnetic forces and hydrodynamic forces generated by relative movement of said impeller with respect to and within the pump housing;   the impeller including a magnet material for deriving drive torque by interaction with currents in windings within the pump housing; and   a coating configured to minimize wear on touching surfaces of the impeller and inner walls of the pump housing during start-up or touch down.   
     
     
         20 . The device of  claim 19 , the impeller including blades, wherein the blades are encapsulated in the coating. 
     
     
         21 . The device of  claim 19 , wherein the coating is applied to the inner walls of the pump housing. 
     
     
         22 . The device of  claim 19 , wherein the coating comprises a thin coating of biologically compatible material. 
     
     
         23 . The device of  claim 19 , wherein the coating comprises a hard material. 
     
     
         24 . The device of  claim 23 , wherein the coating comprises diamond or titanium-nitride. 
     
     
         25 . The device of  claim 19 , wherein the coating is applied to the inner walls of the pump housing, the coating comprising a hard material. 
     
     
         26 . The device of  claim 19 , wherein the coating has a thickness of approximately 1 micron. 
     
     
         27 . A method for making a heart assist device, comprising:
 forming an impeller including blades;   forming a housing for the impeller; and   coating one of the impeller blades and inner walls of the housing to minimize wear between contacting surfaces during a start-up or touch down.   
     
     
         28 . The method of  claim 27 , wherein the coating comprises a biologically compatible material. 
     
     
         29 . The method of  claim 27 , wherein the coating comprises a hard material. 
     
     
         30 . The method of  claim 29 , wherein the coating comprises depositing a coating of the hard material using chemical vapor deposition. 
     
     
         31 . The method of  claim 29 , wherein the coating comprises depositing a coating of the hard material using physical vapor deposition. 
     
     
         32 . The method of  claim 29 , wherein the hard material is diamond or titanium nitride.