Portable blood pumping system

Abstract

A pump ( 100 ) includes a pump housing ( 200 ) having a fluid inlet ( 114 ) and a fluid outlet ( 116 ). An impeller ( 252 ) is disposed within the pump housing ( 200 ) and is rotatable about an axis ( 156 ) to move fluid from the inlet ( 114 ) to the outlet ( 116 ). A flexible drive spring ( 270 ) connects the impeller to a rotating drive mechanism ( 312 ). The spring ( 270 ) transmits torque to the impeller ( 252 ) from the drive mechanism ( 312 ) and preloads the impeller against a surface ( 232 ) of the pump housing ( 200 ).

1 . A pump comprising: 
 a pump housing having a fluid inlet and a fluid outlet;    an impeller disposed within the pump housing and rotatable about an axis to move fluid from the inlet to the outlet;    a flexible drive spring connecting the impeller to a rotating drive mechanism, the spring transmitting torque to the impeller from the drive mechanism and preloading the impeller against a surface of the pump housing.    
   
   
       2 . The pump recited in  claim 1 , wherein the drive spring comprises a helical coil spring.  
   
   
       3 . The pump recited in  claim 1 , wherein the spring is connected to the impeller and drive means by cross pins through respective end turns of the spring.  
   
   
       4 . The pump recited in  claim 1 , wherein the spring is surrounded by a cylindrical sleeve which also rotates about the axis.  
   
   
       5 . The pump recited in  claim 1 , further comprising means for attaching an end of the spring to at least one of the impeller and the drive means and means for preventing deformation of the end of the spring under torque applied by the drive mechanism of the pump.  
   
   
       6 . The pump recited in  claim 1 , wherein at least one end of the spring is connected with means for adjusting the preload on the impeller.  
   
   
       7 . The pump recited in  claim 6 , wherein the means for adjusting comprises a threaded member.  
   
   
       8 . The pump recited in  claim 1 , further comprising a face seal including a fixed face and a moveable face, the fixed face comprising a surface on the pump housing, the movable face comprising a surface on the impeller, the preload on the impeller urging the movable face into engagement with the fixed face.  
   
   
       9 . The pump recited in  claim 8 , wherein the face seal isolates pumped fluid from the drive spring.  
   
   
       10 . The pump recited in  claim 8 , wherein pumped fluid is directed over a fluid side surface of the impeller to cool the face seal.  
   
   
       11 . The pump recited in  claim 8 , wherein the face seal lies on a plane that is aligned with the direction of the hydraulic force on the impeller.  
   
   
       12 . The pump recited in  claim 8 , wherein at least one of the fixed face and movable face is constructed of a material with a thermal conductivity exceeding 35 BTU-in/hr-ft 2 -° F.  
   
   
       13 . The pump recited in  claim 8 , wherein at least one of the fixed face and movable face has a surface modification treatment.  
   
   
       14 . The pump recited in  claim 13 , wherein the surface modification treatment comprises the application of a diamond-like carbon coating to at least one of the fixed face and movable face.  
   
   
       15 . The pump recited in  claim 1 , wherein control components are integrated into the pump housing.  
   
   
       16 . The pump recited in  claim 15 , wherein the control components include at least one pressure transducer integrated with at least one fluid port.  
   
   
       17 . The pump recited in  claim 1 , wherein instrumentation power and signals are transmitted between the pump housing and a base assembly of the pump by contact points.  
   
   
       18 . The pump recited in  claim 1 , further comprising means to manually attach the pump housing to a source of rotary torque and detach the pump housing from the source of rotary torque.  
   
   
       19 . The pump recited in  claim 1 , further comprising a magnetic coupling for coupling the drive mechanism to a drive motor, the magnetic coupling comprising a first magnetic element associated with the drive mechanism and a second magnetic element associated with the drive motor.  
   
   
       20 . The pump recited in  claim 1 , further comprising a controller including a battery power supply and means for transmitting power and signals between the pump and controller.  
   
   
       21 . The pump recited in  claim 20 , wherein the battery power supply comprises a primary cell battery power supply.  
   
   
       22 . The pump recited in  claim 20 , wherein the battery power supply retains a substantially full charge for at least one year.  
   
   
       23 . The pump recited in  claim 1 , wherein the performance as a pump is constant regardless of pump orientation.  
   
   
       24 . A pump comprising: 
 a pump housing having a fluid inlet and a fluid outlet;    an impeller disposed within the pump housing and rotatable about an axis to move fluid from the fluid inlet to the fluid outlet;    a face seal including a fixed face on the pump housing and a rotatable face on the impeller; and    a resilient member that preloads the rotatable face against the fixed face and transmits torque to the impeller.    
   
   
       25 . The pump recited in  claim 24 , further comprising a cylindrical extension that extends axially from the rotatable face on the impeller, the cylindrical extension being disposed in a mating hole in the pump housing to form a radial bearing.  
   
   
       26 . The pump recited in  claim 25 , wherein the inner diameter of the cylindrical extension controls at least one of lateral buckling and torsional buckling of the resilient member.  
   
   
       27 . The pump recited in  claim 24 , wherein the resilient member comprises a spring.  
   
   
       28 . The pump recited in  claim 24 , further comprising a cylindrical tube to control at least one of lateral buckling and torsional buckling of the resilient member.  
   
   
       29 . The pump recited in  claim 24 , wherein the face seal isolates pumped fluid from the resilient member.  
   
   
       30 . The pump recited in  claim 24 , further comprising means for adjusting the preload of the resilient member.  
   
   
       31 . The pump recited in  claim 24 , wherein the fixed face and rotatable face interface with each other along a plane that is aligned with the direction of the hydraulic force on the impeller.  
   
   
       32 . The pump recited in  claim 24 , wherein physical properties of at least one seal surface are modified with a surface modification treatment.  
   
   
       33 . The pump recited in  claim 24 , wherein the pump housing is separable from a prime mover operable to transmit rotational torque to the impeller via the resilient member.  
   
   
       34 . The pump recited in  claim 33 , wherein a magnetic coupling couples the prime mover to the spring.  
   
   
       35 . A pump comprising: 
 a prime mover;    a pump housing having a fluid inlet and a fluid outlet;    an impeller disposed within the pump housing and rotatable about an axis to move fluid from the fluid inlet to the fluid outlet;    a face seal including a fixed face on the pump housing and a rotatable face on the impeller;    a spring that preloads the rotatable face against the fixed face and transmits torque to the impeller from the prime mover;    a sleeve that encircles the spring along a substantial portion of the length of the spring and helps prevent buckling of the spring; and    means for reinforcing at least one end portion of the spring.    
   
   
       36 . The pump recited in  claim 35 , further comprising means for adjusting the preload of the spring.  
   
   
       37 . The pump recited in  claim 35 , wherein the face seal is positioned along a plane that coincides with the radial hydraulic force on the impeller.  
   
   
       38 . A blood pumping system comprising: 
 an extracorporeal blood pump comprising a motor, a pump housing having an inlet and an outlet, and an impeller disposed within the pump housing and rotatable about an axis to move fluid from the inlet to the outlet;    a portable control unit operative to supply power to the pump and receive signals from the pump, the control unit comprising a battery power supply;    the blood pump having a priming volume of no more than 12 milliliters and having a pump head hydraulic efficiency of at least 40 percent.