Methods Of Operating A Rotary Blood Pump

Abstract

Various “contactless” bearing mechanisms including hydrodynamic, hydrostatic, and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. These design features may be combined. In one embodiment, the pump apparatus includes a rotor having a bore, a ring-shaped upper rotor bearing magnet, and a ring-shaped lower rotor bearing magnet. The bearing magnets are concentric with the bore. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

1 . A method of assembling a centrifugal fluid pump comprising:
 disposing a rotor in a housing having a center-post for rotation of said rotor around said center-post;   forming a magnet assembly for magnetically biasing said rotor in a first direction;   configuring at least one ring-shaped center-post magnet and at least one ring-shaped rotor magnet for providing a stabilizing force to said rotor during operation; and   positioning said rotor in proximity to said housing such that hydrodynamic forces are created in opposition to said biasing during rotation of said rotor.   
     
     
         2 . A method according to  claim 1 , wherein the disposing comprises disposing said rotor in said housing to form a leakage flow path between said rotor and said housing assembly. 
     
     
         3 . A method according to  claim 1 , wherein said positioning comprises placing said rotor in proximity to contoured hydrodynamic surfaces. 
     
     
         4 . A method according to  claim 3 , wherein said positioning further comprises placing said rotor in proximity to contoured hydrodynamic surfaces formed on a surface of said housing assembly. 
     
     
         5 . A method according to  claim 1 , further comprising adjusting the relative position of said at least one ring-shaped center-post magnet and said at least one ring-shaped rotor magnet so as to fine tune the biasing of said rotor axially in said first direction. 
     
     
         6 . A method according to  claim 4 , wherein said adjusting includes axially moving said at least one ring-shaped center-post magnet relative to said at least one ring-shaped rotor magnet. 
     
     
         7 . A method of assembling a centrifugal blood pump comprising:
 obtaining a housing having a spindle;   disposing a rotor into said housing for rotation of said rotor around said spindle;   forming a magnet arrangement for magnetically biasing said rotor in a first direction;   combining at least one ring-shaped spindle magnet and at least one ring-shaped rotor magnet into a relationship so as to provide a stabilizing force to said rotor during operation of said pump; and,   positioning said rotor in proximity to a surface of said housing such that hydrodynamic forces are created in opposition to said biasing during operation of said pump.   
     
     
         8 . A method according to  claim 7 , wherein the disposing comprises disposing said rotor in said housing to form a leakage flow path between said rotor and said housing during operation of said pump. 
     
     
         9 . A method according to  claim 7 , wherein said positioning comprises placing said rotor in proximity to contoured hydrodynamic surfaces. 
     
     
         10 . A method according to  claim 9 , wherein said positioning further comprises placing said rotor in proximity to contoured hydrodynamic surfaces formed on a surface of said housing. 
     
     
         11 . A method according to  claim 7 , further comprising adjusting the relative position of said at least one ring-shaped spindle magnet and said at least one ring-shaped rotor magnet so as to modify the biasing of said rotor axially in said first direction. 
     
     
         12 . A method according to  claim 11 , wherein said adjusting includes axially moving said at least one ring-shaped center-post magnet relative to said at least one ring-shaped rotor magnet. 
     
     
         13 . A method according to  claim 9 , wherein said placing comprises placing said rotor in proximity to curved and tapered ramps. 
     
     
         14 . A method according to  claim 13 , wherein said placing comprises placing said rotor in proximity to curved and tapered ramps that are disposed on said housing. 
     
     
         15 . A method of constructing a centrifugal liquid fluid pump comprising:
 obtaining a housing fabricated to include a stator post;   disposing a rotor around said stator post for rotation of said rotor around said stator post;   assembling a magnet arrangement in said housing that serves to magnetically bias said rotor in a first direction;   combining at least one ring-shaped stator post magnet into a relationship with at least one ring-shaped rotor magnet so as to provide a stabilizing force to said rotor during operation of said pump; and,   positioning said rotor in proximity to a surface of said housing such that hydrodynamic forces are created in opposition to said biasing during operation of said pump.   
     
     
         16 . A method according to  claim 15 , wherein the disposing comprises disposing said rotor in said housing to form a leakage flow path between said rotor and said housing during operation of said pump. 
     
     
         17 . A method according to  claim 15 , wherein said positioning comprises placing said rotor in proximity to contoured hydrodynamic surfaces. 
     
     
         18 . A method according to  claim 17 , wherein said positioning further comprises placing said rotor in proximity to contoured hydrodynamic surfaces formed on a surface of said housing. 
     
     
         19 . A method according to  claim 15 , further comprising adjusting the relative position of said at least one ring-shaped stator-post magnet and said at least one ring-shaped rotor magnet so as to finely adjust the biasing of said rotor axially in said first direction. 
     
     
         20 . A method according to  claim 19 , wherein said adjusting includes axially moving said at least one ring-shaped stator-post magnet relative to said at least one ring-shaped rotor magnet. 
     
     
         21 . A method according to  claim 18 , wherein said placing comprises placing said rotor in proximity to curved and tapered ramps. 
     
     
         22 . A method according to  claim 21 , wherein said placing comprises placing said rotor in proximity to curved and tapered ramps that are disposed on said housing