Search

EP-3826695-B1 - ROTARY BLOOD PUMP

EP3826695B1EP 3826695 B1EP3826695 B1EP 3826695B1EP-3826695-B1

Inventors

  • BUSCH, DAVID
  • MAROUS, JOHN, C., III
  • MCCOPPIN, ANTHONY, S.
  • SVITEK, ROBERT, G.

Dates

Publication Date
20260506
Application Date
20190123

Claims (14)

  1. A centrifugal blood pump (10) comprising: a housing (12) having a pumping chamber (18), an inlet (20) with an inlet axis (42), and an outlet (22) with an outlet axis (44), the inlet and the outlet being in fluid communication with the pumping chamber; an impeller (34) rotatably disposed within the pumping chamber; a bearing mechanism (38) supporting the impeller within the pumping chamber; and a single strut (46) connected to the housing at the inlet to support at least a portion of the bearing mechanism, wherein the strut is connected to the housing at a circumferential position about the inlet axis such that a major axis of the strut and the outlet axis define a predetermined acute angle (α) in a cross-sectional plane perpendicular to the inlet axis to reduce or eliminate damage to blood flowing around the strut, characterised in that the predetermined acute angle is about 15° to about 75°.
  2. The centrifugal blood pump of claim 1, wherein the strut has a single connection point with the housing in the cross-sectional plane perpendicular to the inlet axis.
  3. The centrifugal blood pump of claim 1, wherein at least a portion of the strut has a teardrop cross-sectional shape.
  4. The centrifugal blood pump of claim 1, wherein the impeller (34) has at least one passage (60) defining a secondary flow path.
  5. The centrifugal blood pump of claim 4, wherein the at least one passage is substantially perpendicular to the outlet axis.
  6. The centrifugal blood pump of claim 4, wherein, during operation of the blood pump, the impeller delivers a first portion of blood flow from the inlet directly to the outlet, and delivers a second portion of the blood flow from the inlet to the outlet via the at least one passage.
  7. The centrifugal blood pump of claim 1, wherein the bearing mechanism comprises: a radial bearing (86) having a first permanent magnet (66) associated with the impeller and a second permanent magnet (88) associated with the housing, the first permanent magnet magnetically interacting with the second permanent magnet to radially position the impeller within the pumping chamber; and an axial bearing (90) comprising a first bearing element (92) associated with the impeller (34) and a second bearing element (94) connected to the strut (46).
  8. The centrifugal blood pump of claim 7, wherein the first bearing element is ball-shaped and the second bearing element is cup-shaped to receive at least a portion of the ballshaped first bearing element or the second bearing element is ball-shaped and the first bearing element is cup-shaped to receive at least a portion of the ball-shaped second bearing element.
  9. The centrifugal blood pump of claim 7, wherein the first bearing element is a jewel bearing.
  10. The centrifugal blood pump of claim 7, wherein the second bearing element is made from a ceramic material.
  11. The centrifugal blood pump of claim 7, wherein the first permanent magnet is axially offset relative to the second permanent magnet by a predetermined distance to urge the impeller in a direction toward the inlet with a predetermined axial force.
  12. The centrifugal blood pump of claim 1, further comprising a motor mechanism for rotating the impeller within the pumping chamber, the motor mechanism having a permanent magnet rotor (74) associated with the impeller and an electromagnetic coil (82) stator associated with the housing.
  13. The centrifugal blood pump of claim 1, the impeller having at least one passage defining a secondary flow path extending in a direction substantially parallel to the inlet axis; wherein, during operation of the blood pump, the impeller delivers a first portion of blood flow from the inlet directly to the outlet, and delivers a second portion of the blood flow from the inlet to the outlet via the at least one passage.
  14. The centrifugal blood pump of claim 13, wherein the at least one passage defining the secondary flow path is substantially perpendicular to the outlet axis.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to United States Provisional Application No. 62/702,562, filed on July 24, 2018. BACKGROUND OF THE DISCLOSURE Field of the Disclosure The present disclosure is generally related to a centrifugal rotary blood pump, throughout the description referred to simply as rotary blood pump, and, in particular, to a rotary blood pump having a bearing mechanism for supporting an impeller within a pumping chamber and a drive mechanism for rotatably driving the impeller within the pumping chamber. Prior art rotary blood pumps are known, e.g., from US5,360,317 A, US 5,746,575 or US 2018/369467 A1. Description of Related Art Rotary blood pumps have long been used with assisting or supplementing the function of a human heart. For example, rotary blood pumps assist heart function due to a damaged left ventricle, or for temporary heart bypass during cardiac surgery. In general, a rotary blood pump has an impeller disposed within a pumping chamber of a pump housing. Blood is delivered via an axial inlet of the housing and is pumped by the impeller to a radial outlet. The impeller is rotatably driven within the pumping chamber by a drive mechanism, such as a drive magnet in the impeller that is rotatably driven by an electromagnet in the housing. Due to high rotating speeds of the impeller during pump operation (2,000 to 7,500 rpm), the impeller must be adequately supported within the pump housing to prevent damage to the blood cells due to shearing or flow stagnation. In some existing pump designs, the impeller is fully magnetically suspended within the pumping chamber. Such impeller support systems often require complex control of the magnets used for suspending the impeller. In other designs, the impeller may be hydrodynamically suspended within the pumping chamber, where hydrodynamic force of blood within the pumping chamber is used to support the impeller and prevent the impeller from contacting the sidewalls of the pumping chamber. With hydrodynamic impeller support, the impeller is often free to contact the sidewalls of the pumping chamber during pump startup until a sufficient fluid pressure is built. As a result, blood cells may be damaged during pump startup. Some rotary blood pumps have a fully mechanical bearing supporting the impeller within the pump housing. A disadvantage of mechanical bearings is that they may transfer heat to the blood and may result in blood clotting. In view of these and other disadvantages of conventional rotary blood pumps, there is a need in the art for improved rotary blood pumps having a bearing mechanism for supporting the impeller in a manner that overcomes the shortcomings of existing rotary blood pumps. SUMMARY OF THE INVENTION The present invention is generally related to a rotary blood pump, and, in particular, to a rotary blood pump having a bearing mechanism for supporting an impeller within a pumping chamber, and a drive mechanism for rotatably driving the impeller within the pumping chamber. According to the invention a centrifugal blood pump according to claim 1 is provided. Preferred embodiments are defined in dependent claims 2 to 14. Further details and advantages of the various examples described in detail herein will become clear upon reviewing the following detailed description of the various examples in conjunction with the accompanying drawing figures. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front, perspective cross-sectional view of a rotary blood pump in accordance with one example of the present disclosure;FIG. 2 is an exploded side view of the rotary blood pump shown in FIG. 1 shown without a lower housing portion;FIG. 3 is a perspective view of an inlet housing of the rotary blood pump shown in FIG. 1;FIG. 4A is a top view of the inlet housing shown in FIG. 3;FIG. 4B is a bottom view of the inlet housing shown in FIG. 3;FIG. 4C is a detailed top view of the inlet housing of FIG. 3 showing a strut;FIG. 5A is a side cross-sectional view of the inlet housing shown in FIG. 3;FIG. 5B is a longitudinal cross-sectional view of the strut taken along line A-A in FIG. 4C;FIG. 5C is a lateral cross-sectional view of the strut taken along line B-B in FIG. 4C;FIG. 6 is a perspective view of an impeller of the rotary blood pump shown in FIG. 1;FIG. 7 is a side view of the impeller shown in FIG. 6;FIG. 8 is a top view of the impeller shown in FIG. 6;FIG. 9 is a side cross-sectional view of the impeller shown in FIG. 6;FIG. 10 is an exploded side view of the impeller shown in FIG. 6;FIG. 11 is a pressure distribution graph showing static pressure at various portions of the inlet housing; andFIG. 12 is a top view of the inlet housing showing a net force diagram based on static pressure values from FIG. 11. DETAILED DESCRIPTION OF THE INVENTION The illustrations generally show preferred and non-limiting examples of the apparatus and methods of the present disclosure. While the description presents variou