Blood pump

Abstract

The invention relates to an intravascular blood pump (1) comprising a pumping device (11) having a pump portion (3) and a drive portion (4), wherein the pump portion (3) comprises a pump housing (2) having a primary blood flow inlet (211) and a primary blood flow outlet (22) hydraulically connected by a primary passage (30) and the drive portion (4) comprises a stator (40) and a rotor (41) rotatable about a rotational axis (10) and configured to rotate a primary impeller (31) configured to convey a primary blood flow along the primary passage (30) from the primary blood flow inlet (211) to the primary blood flow outlet (22), the drive portion (4) further comprises a secondary blood flow inlet (23) and a secondary blood flow outlet (24), the secondary blood flow inlet (23) and the secondary blood flow outlet (24) are hydraulically connected by a secondary passage extending through an axial gap (401) between the rotor (41) and the stator (40) and a secondary impeller (42) arranged at a drive portion end (DSE) of the rotor (41) and rotatable about the rotational axis (10) together with the rotor (41), the secondary impeller (42) comprises one or more secondary impeller blades (421) configured to convey a secondary blood flow along the secondary passage from the secondary blood flow inlet (23) to the secondary blood flow outlet (24) in a direction towards a pump portion end (PSE) of the pumping device (11), the rotor (41) is mounted in a blood cleaning radial slide bearing (47) having an inner rotor bearing surface (4211) and an outer rotor bearing surface (4311), and the secondary impeller (42) forms the inner rotor bearing surface (4211) of the radial slide bearing (47).

Description

Technical Field

[0001] This invention relates to an intravascular blood pump that supports or replaces heart function by generating additional blood flow in a patient's blood vessels. Background Technology

[0002] Different types of blood pumps are known, such as axial blood pumps, centrifugal blood pumps, and hybrid or diagonal blood pumps, in which blood flow is caused by both axial and radial forces. Intravascular blood pumps are typically inserted percutaneously, for example, via the femoral artery into the left ventricle to bridge the aortic valve, or via the femoral vein into the right ventricle.

[0003] The rotary blood pump has a rotation axis. In this patent application, the terms "radial" and "axial" refer to the axis of rotation, and respectively to "radial direction relative to the axis of rotation" and "along the axis of rotation". The term "inner" means radially toward the axis of rotation, and the term "outer" means radially away from the axis of rotation.

[0004] Intravascular blood pumps typically include a pumping device as the main component. This pumping device has a pump section and a drive section. The pump section includes a primary impeller for pumping blood from a blood inlet to a blood outlet, and the drive section includes a motor for driving the primary impeller. The pump section may include a flexible, bendable cannula located between the blood inlet and outlet.

[0005] The pumping device includes a pump portion end disposed on the pump side of the pumping device. The pumping device also includes a drive portion end disposed on the drive side of the pumping device. The blood pump may further include a conduit connected to the pumping device for supplying the pumping device with, for example, energy and / or a cleansing fluid. The conduit may be connected to the pump portion end, but most of it is connected to the drive portion end of the pumping device. It is also conceivable to rotate the impeller forward and backward. In this case, the blood inlet and blood outlet of the pump portion can be interchanged.

[0006] Typically, the impeller is supported within the pumping unit by at least one impeller bearing. Different types of rotor bearings are known, such as sliding bearings, particularly hydrodynamic sliding bearings, pivot bearings, hydrostatic bearings, ball bearings, etc., and combinations thereof. In particular, contact bearings can be implemented as "blood-immersed bearings," where the bearing surface is in contact with blood. Problems during operation may include friction and heat. If the bearing is immersed in blood, another problem may be blood clotting due to insufficient heating or cleaning.

[0007] WO 2017 / 021465 discloses an example of a radial sliding bearing for blood cleaning. Figure 33 shows an impeller assembly comprising a generally cylindrical primary impeller. Primary impeller blades extend toward the axis of rotation of the primary impeller. The tips of the primary impeller blades form the outer rotor bearing surface of the sliding bearing. The cylindrical surface of a pin arranged at the center of the primary impeller forms the inner rotor bearing surface of the sliding bearing. An auxiliary impeller is disposed on the opposite side of the drive unit from the primary impeller for cooling the rotor and stator of the drive unit, and rotates with the rotor. The auxiliary impeller pumps blood into the axial gap between the stator and rotor. At the axial end of the auxiliary impeller, a sliding bearing is disposed between the inner end of the auxiliary impeller and the bearing pin. This configuration requires a large axial construction space, thus resulting in a large-volume blood pump that is difficult to advance in blood vessels. Summary of the Invention

[0008] The purpose of this invention is to provide a compact blood pump in which blood flows through the axial gap between the stator and the rotor.

[0009] This is achieved by having a blood pump according to the invention. Preferred embodiments and further developments of the invention are described below.

[0010] According to a first aspect of the invention, an intravascular blood pump includes a pumping device having a pump portion and a drive portion. The pump portion includes a pump housing having a primary blood flow inlet and a primary blood flow outlet, the primary blood flow inlet and the primary blood flow outlet being hydraulically connected via a primary passage. The drive portion includes a stator and a rotor, the stator and rotor being rotatable about a rotation axis and configured to rotatably drive a primary impeller. The primary impeller is configured to deliver primary blood flow from the primary blood flow inlet to the primary blood flow outlet along the primary passage. The drive portion also includes an auxiliary blood flow inlet and an auxiliary blood flow outlet, which are hydraulically connected via an auxiliary passage, such that auxiliary blood flow can be delivered from the auxiliary blood flow inlet to the auxiliary blood flow outlet along the auxiliary passage. The auxiliary passage includes an axial clearance extending between the rotor and the stator. The axial clearance is preferably also the magnetic clearance of an electric motor including the stator and the rotor. An auxiliary impeller disposed at the end of the drive portion of the rotor is also provided, the auxiliary impeller being rotatable together with the primary impeller about a rotation axis and including one or more auxiliary impeller blades configured to deliver auxiliary blood flow through the auxiliary passage. Furthermore, the blood pump includes a radial sliding bearing for blood washing of the rotor. The radial sliding rotor bearing includes an inner rotor bearing surface and an outer rotor bearing surface. An auxiliary impeller forms the inner rotor bearing surface of the radial sliding rotor bearing. Therefore, the blood washing sliding bearing of the auxiliary impeller is arranged radially outward from the auxiliary impeller. This allows for the construction of an axially compact blood pump.

[0011] Preferably, the radial sliding rotor bearing for blood washing is arranged close to the outer periphery of the pump housing, allowing heat conduction from the outer rotor bearing surface through the pump housing to the surrounding general blood flow to occur. This further helps to construct a compact and reliable blood pump in which heat is effectively removed. This may also facilitate the delivery of cooler blood to the axial clearance.

[0012] Preferably, the auxiliary impeller is a radially or radially axially conveying impeller. Therefore, the auxiliary impeller generates centrifugal force in the auxiliary blood flow to produce pressure.

[0013] Preferably, the inner bearing surfaces of the rotor, formed by the auxiliary impeller and the rotor, have a common outer diameter. Then, the auxiliary blood flow can enter the axial gap without significant deflection. Furthermore, considering that the intravascular blood pump must have a small outer diameter because it must advance through the blood vessel to the heart, the radially inward construction space is optimally utilized due to the identical outer diameter of the inner rotor bearing surfaces and the rotor. That is, the pressure in the blood entering the axial gap is increased to a limit by the auxiliary impeller, a limit limited only by the radially constructed space at the end of the blood pump's drive section.

[0014] Preferably, at least two, more preferably, at least three auxiliary impeller blades extend to the outer rotor bearing surface. The surfaces of the auxiliary impeller blades closest to the outer rotor bearing surface together form the inner rotor bearing surface. This is the surface of the auxiliary impeller on which the rotor is mounted relative to the outer rotor bearing surface. Therefore, the inner rotor bearing surface is discontinuous and comprises at least two, preferably at least three, separate sections defined by the tips of the impeller blades. In this way, the tips of the auxiliary impeller blades can form part of a radially sliding rotor bearing. The outer rotor bearing surface can be a single continuous surface. Furthermore, alternatively, the outer rotor bearing surface may have grooves and / or slots.

[0015] Preferably, at least one auxiliary impeller blade protrudes axially from the auxiliary impeller relative to the axis of rotation. In this way, the blade can form the axial end of the rotating portion of the blood pump. This axial end can be opened to allow blood to flow into the auxiliary impeller.

[0016] Preferably, the radially outer edge of at least one auxiliary impeller blade is chamfered. A corresponding chamfer may be arranged between a portion of the axially extending auxiliary impeller blade and a portion of the radially extending auxiliary impeller blade relative to the axis of rotation. In particular, the blood pump may include an axially narrowing section between the supply conduit and the pump housing with a larger diameter. The narrowing facilitates the pump's advance through the blood vessel. Preferably, the chamfer of the auxiliary impeller is arranged below the narrowing section. This chamfer allows for the construction of a more compact blood pump.

[0017] Preferably, at least one auxiliary blade forms an auxiliary pump clearance with the inner wall of the pump housing or with another portion disposed therein. The auxiliary pump clearance preferably has a radially extending outer boundary that extends axially and forms part of a radially sliding rotor bearing. Preferably, the auxiliary pump clearance also has a radially extending axial end disposed between at least one auxiliary impeller blade and the inner wall of the pump housing, preferably located at the chamfered end of the radially extending end surface of the blade. The radially extending portion of the pump clearance retains the pressure established by the auxiliary impeller blade. Forming this clearance in an axial-radial direction, such as along the chamfer, helps to construct a compact blood pump. In particular, the pump housing may gradually narrow at the chamfered location.

[0018] Preferably, at least one, and most preferably all, of the auxiliary impeller blades are straight in their radial extension direction. Preferably, at least one, and preferably all, of the auxiliary impeller blades extend radially approximately or precisely relative to the axis of rotation, or are inclined toward this radial direction. The pumping effect of radially extending auxiliary impeller blades is independent of the direction of rotation of the auxiliary impeller. Straight auxiliary impeller blades tend to cause less blood clotting.

[0019] Preferably, at least two, and more preferably at least three, auxiliary impeller blades have radially rising ramps on their outer circumferential surfaces relative to the axis of rotation along the circumferential direction of the auxiliary impeller. Thus, the hydrodynamic sliding rotor bearing can be formed by combining the blade tips with a generally annular outer rotor bearing surface. The ramps are configured to establish pressure in the bearing clearance of the hydrodynamic sliding rotor bearing in the rotational direction. The ramps can be inclined along the entire width of the auxiliary impeller blade in its circumferential direction. Alternatively, two ramps can be arranged in opposite directions along the circumference of the auxiliary impeller, starting from opposite ends of the auxiliary impeller blade tips, thereby achieving maximum radial rise of the auxiliary impeller blade in the middle portion of a portion of the auxiliary impeller blade tips. Such an impeller can operate in two opposite rotational directions. Equivalent construction details can be additionally or alternatively provided on the outer impeller bearing surface.

[0020] Preferably, the specifications of the aforementioned outer peripheral surface are applied to the axial or radial end faces of the auxiliary impeller blades. The end faces of the auxiliary impeller blades may extend radially relative to the axis of rotation, or extend along a chamfer disposed at the edge of the auxiliary impeller blades. The hydrodynamic end faces of the aforementioned type of auxiliary impeller blades can be realized in the bearing surfaces of an internal axial sliding rotor bearing or an axial-radial sliding rotor bearing between the auxiliary impeller and the non-rotating part of the blood pump (e.g., the pump housing). The outer axial or axial-radial rotor bearing surface of the axial sliding rotor bearing may, for example, be disposed at the pump housing. The axial force of the impeller can be transmitted through the axial or axial-radial rotor bearing.

[0021] Preferably, the axial or axial-radial rotor bearing surfaces are made of ceramic material. For example, the ceramic material can be a ceramic coating. Alternatively, corresponding portions of the impeller and / or pump housing can be made entirely of ceramic material.

[0022] Preferably, radially projecting protrusions are arranged on the outer and / or inner rotor bearing surfaces, and the apex of the protrusion extends circumferentially. The protrusions can extend on either the outer or inner rotor bearing surfaces. Preferably, the radius of the apex is greater than one-tenth of the diameter of the auxiliary impeller. The advantage of such protrusions is that, when the rotating part of the blood pump rotates transversely to the main rotation direction, no sharp edges at the ends of the rotating parts contact the surrounding non-rotating parts, which would otherwise damage the pump surface. Instead, only the protruding protrusions contact the non-rotating opposing surfaces. Therefore, the risk of damage to the rotor bearings due to rotation of the axis of rotation is reduced.

[0023] Preferably, the surface of the inner rotor bearing is made of a ceramic material. For example, the surface of the inner rotor bearing can be provided with a ceramic coating. The hardness of the ceramic material improves the wear characteristics of the inner rotor bearing surface. Preferably, the ceramic material is inert in terms of its reaction with blood.

[0024] Preferably, the auxiliary impeller is a single piece of ceramic material. The auxiliary impeller can also be made of a non-ceramic material coated with ceramic material.

[0025] Preferably, the surface of the outer rotor bearing is also made of ceramic material. For example, the surface of the outer rotor bearing can be provided with a ceramic coating.

[0026] Preferably, the pumping device includes specific components, such as rotor bearing rings, that form the surface of the outer rotor bearing, which is made of ceramic material. Individual ceramic components provide good shape stability to the outer rotor bearing surface, which is particularly important because the inner rotor bearing surface is small and the surface pressure increases at the tips of the auxiliary impeller blades.

[0027] Preferably, the ceramic material is silicon carbide. Compared to most other ceramic materials, silicon carbide has the advantage of high thermal conductivity. Therefore, heat can be effectively transferred away from the sliding rotor bearing. Heat conduction can occur through the rotor towards the impeller or through the pump housing, for example, particularly through the rotor bearing rings.

[0028] Preferably, the axial length of the auxiliary impeller is less than its maximum outer diameter. This prevents the auxiliary impeller from extending excessively along the axis of rotation, placing it within a narrow section of the blood pump. Consequently, the pumping effect is primarily generated in the radial direction, which is more effective than in the axial direction. This is advantageous for constructing compact blood pumps.

[0029] Preferably, the primary impeller is arranged on one side of the rotor, opposite to the side of the rotor where the auxiliary impeller is located. This arrangement has the advantage that the bearings at the ends of the rotating parts of the blood pump, such as the radial sliding bearings at the auxiliary impellers, are optimally mounted to the rotating parts in terms of stiffness against rotation of the axis of rotation.

[0030] Preferably, the auxiliary blood flow outlet is located outside the primary passage of the primary impeller. Therefore, the auxiliary blood flow is separated from the main blood flow. The blood delivered via the auxiliary passage then mixes only with the blood from the primary passage outside the primary passage. Because the blood flows in opposite directions, the resulting hydraulic losses are smaller, and the auxiliary blood flow is independent of the primary blood flow, which depends on preload and afterload conditions. In other words, due to the separation of the main and auxiliary blood flows, the auxiliary blood flow depends only on the pump's rotation.

[0031] Preferably, the auxiliary blood flow outlet is arranged at an angle or perpendicular to the direction of the main blood flow delivered by the pump section. When the primary blood flow flows near the auxiliary blood flow outlet, blood is drawn out from the auxiliary blood flow outlet by the Venturi effect. This supports the auxiliary blood flow.

[0032] Preferably, the auxiliary blood flow inlet includes multiple inlet holes. The inlet holes are preferably arranged circumferentially about a rotation axis. More preferably, the inlet holes are arranged in a circular pattern. More preferably, a wire channel is arranged in the gap between two adjacent inlet holes. For example, the wire channel can be used to accommodate at least one power supply line for the drive unit. This arrangement of the inlet holes and wire channels constitutes a compact design of the blood pump.

[0033] The axial clearance between the rotor and stator is located downstream of the auxiliary impeller. The auxiliary impeller can be arranged in the cavity between the auxiliary blood inlet and the axial clearance. Specifically, the auxiliary impeller delivers blood radially or radially-axially. Along the auxiliary blood flow path, downstream of the auxiliary blood inlet, an auxiliary inlet through-hole is provided in the wall of the pump housing. Blood can enter the cavity through the inner end of the auxiliary inlet through-hole. The inner end of the auxiliary inlet through-hole is preferably arranged radially further inward than the axial clearance. Centrifugal force acting between the inner and outer regions of the auxiliary impeller generates pressure to deliver blood through the axial clearance. Specifically, the outermost radial section of the auxiliary blood inlet can be arranged radially further inward than the innermost radial section of the inlet in the axial clearance.

[0034] Preferably, the pumping device further includes a three-stage impeller. The three-stage impeller is preferably positioned downstream of the axial clearance. Preferably, the three-stage impeller is configured to draw blood out of the axial clearance. The three-stage impeller thus increases the flow rate of blood through the auxiliary passage.

[0035] Preferably, the third-stage impeller can rotate about the axis of rotation. The third-stage impeller can rotate together with the rotor.

[0036] Preferably, the auxiliary blood flow outlet is located at the radial gap formed between the primary impeller and the stator. More preferably, blood can flow out of the radial gap over its entire outer circumferential cross-section. This large outflow cross-section reduces the hydraulic resistance of the auxiliary blood flow channel.

[0037] Specifically, the rotatable wall of the radial gap can rotate together with the rotor. This creates a helical resistance flow of blood, which, through its rotation within the gap, enhances blood flow through the auxiliary pathway by centrifugal force on the blood within the helical resistance flow.

[0038] Preferably, the fixed wall of the radial clearance is arranged opposite to the rotatable wall of the radial clearance. The fixed wall is preferably mechanically connected to the stator.

[0039] Preferably, the third-stage impeller is disposed within the radial clearance. Preferably, the third-stage impeller forms part of the rotatable wall of the radial clearance. Preferably, the third-stage impeller includes at least one third-stage impeller blade. The third-stage impeller blade is preferably configured to deliver blood in the radial direction. The third-stage impeller blade may extend approximately or precisely in the radial direction relative to the axis of rotation. Thus, the effect of the third-stage impeller is independent of its direction of rotation.

[0040] Preferably, an inflow into the third-stage impeller is provided at the outflow end of the axial clearance. Therefore, the third-stage impeller can effectively draw blood directly from the axial clearance. The short connection between the axial and radial clearances reduces hydraulic resistance along the auxiliary blood flow channel. Attached Figure Description

[0041] The above overview and the following detailed description of the preferred embodiments will be better understood when read in conjunction with the accompanying drawings. However, the scope of this disclosure is not limited to the specific embodiments disclosed in the drawings. In the drawings:

[0042] Figure 1 This is a cross-sectional view of a first embodiment of the blood pump of the present invention;

[0043] Figure 2 for Figure 1 An enlarged view of a portion of the pump section;

[0044] Figure 3 for Figure 1 A magnified view of a portion of the drive section;

[0045] Figure 4 A perspective view of the pump portion end of the first embodiment of the blood pump;

[0046] Figure 5 In essence Figure 4 The view is shown, but it has a transparent pump housing;

[0047] Figure 6 In essence, it is with Figure 5 Same view, but a second embodiment view of the blood pump;

[0048] Figure 7 A perspective view of an embodiment of a two-stage impeller;

[0049] Figure 8 A perspective view of the separator ring of a first embodiment of a blood pump;

[0050] Figure 9 A perspective view of the separator ring of a second embodiment of the blood pump;

[0051] Figure 10 A perspective view shows a cross-section of the end of the blood pump drive section, which reveals the auxiliary impeller;

[0052] Figure 11A Perspective view of the impeller and rotor bearing rings;

[0053] Figure 11B A perspective view of a rotor bearing ring with cutouts; and

[0054] Figure 12 A perspective view of the three-stage impeller of the first or second embodiment. Detailed Implementation

[0055] exist Figure 1 The figure shows a cross-sectional view of a first embodiment of an intravascular blood pump. Rotating parts are not shown cut open. The intravascular blood pump 1 includes a pumping device 11 and a supply line in the form of a catheter 5 attached thereto.

[0056] The pumping device 11 includes, at least in its intermediate portion, a substantially cylindrical pump housing 2. The pump housing 2 includes a blood inlet 21 and a blood outlet 22. Figure 1 In the image, the pump housing 2 appears to consist of two separate parts, but these parts are either integral or connected as one unit.

[0057] As in Figure 2 The enlarged display of the pump section shown, and in Figure 4 and 5 As can be better seen in the front perspective view shown, blood flow inlet 21 includes a primary blood flow inlet 211 and a secondary blood flow inlet 212. The primary blood flow inlet 211 surrounds the secondary blood flow inlet 212. The primary blood flow inlet 211 and the secondary blood flow inlet 212 are separated by an inflow separator 26. Inside the inflow separator 26, the inflow separator 26 includes an impeller bearing ring 27, which... Figure 8The following are shown separately. Furthermore, the pumping device 11 includes a primary impeller 31, in which a secondary impeller 32 is integrated. The primary and secondary impellers 31 and 32 can rotate together about the rotation axis 10. The secondary impeller 32 can be... Figure 7 The design shown has an insert form and can be disposed inside the secondary impeller cavity 312 of the primary impeller 31. The secondary impeller cavity 312 is open toward the pump portion end PSE of the pumping device 11. Alternatively, the primary impeller 31 and the secondary impeller 32 are formed integrally.

[0058] Primary blood flow 1BF flows from primary blood flow inlet 211 to primary impeller 31 outside separator 26, and is further transported by primary impeller 31 to primary blood flow outlet 22 through primary blood flow path 30. Secondary blood flow 2BF flows from secondary blood flow inlet 212 to secondary impeller 32 through separator 26, and is further transported by secondary impeller 32 to primary blood flow path 30 through multiple secondary blood flow paths 321.

[0059] Therefore, the blood flow reaching the pumping device 11 at the end of the pump section, preferably covering almost the entire cross-section of the pumping device 11, can flow into the primary and secondary blood inlets 211, 212 without significant deflection. Due to the central location of the secondary blood inlet 212, blood from the middle of the blood flow can also enter the pumping device 11 without deflection. This is advantageous because blood flow is typically laminar, with the highest velocity at the center.

[0060] The primary impeller 31 includes primary impeller blades 313 extending into the primary blood flow path 30, and a primary impeller channel 311 is provided between the primary impeller blades 313. The primary impeller channel 311 has a primary passage inlet 314 at each end of the primary impeller channel 311 facing the pump section end PSE. The secondary impeller 32 includes at least one, and particularly two, secondary blood flow paths 321 in the form of channels, and is therefore also referred to hereinafter as secondary impeller channels 321. The secondary impeller channel 321 has a secondary channel inlet 324 located at the upstream end of the secondary impeller channel 321. The secondary pitch is preferably the same as the primary pitch, or may be different to some extent, provided that unintended flow conditions, such as turbulence, can be prevented. At one end of the secondary impeller 32 facing the drive section end DSE, a connecting through opening 315 is provided between the secondary impeller cavity 312 and one of the primary impeller channels 311. The through opening 315 defines a secondary blood flow outlet 213 at one end in the direction of blood flow. The secondary blood flow outlet 213 is further arranged radially outward relative to the axis of rotation 10. Therefore, the centrifugal force generated by the rotation of the secondary impeller 32 pushes the blood outward in the radial direction. In this way, the secondary blood flow 2BF is delivered through the secondary blood flow inlet 212 and further through the secondary impeller channel 321 of the secondary impeller 32, and merges with the primary blood flow 1BF flowing through the primary impeller channel 311 of the primary impeller 31. Thus, the pumped blood flow PBF is formed. The pumped blood flow PBF exits the pumping device 11 at the blood flow outlet 22.

[0061] The primary and secondary impellers 31 and 32 are jointly mounted in the impeller bearing 37. They are connected via the secondary impeller cavity 312 or integrally formed as a single component. The inflow separator 26 includes an impeller bearing ring 27 disposed inside the inflow separator 26. The outer impeller bearing surface 277 of the impeller bearing 37 is disposed inside the impeller bearing ring 27. The impeller bearing 37 also includes an inner impeller bearing surface 327 disposed on the outer circumference of the secondary impeller 32.

[0062] The primary impeller 31 is fixedly connected to a tapered portion 314 leading to the blood outlet 22. The tapered portion 314 guides the pumped blood flow PBF in a radially outward direction relative to the axis of rotation 10. The blood then reaches the blood outlet 22.

[0063] From the narrowing portion 314 toward the pump section end PSE, the drive section 4 is disposed inside the pump housing 2 of the pumping device 11. The drive section 4 includes a stator 40 and a rotor 41. An axial clearance 401 is provided between the stator 40 and the rotor 41. To cool the stator 40 and the rotor 41, the axial clearance 401 is cleaned with blood. For this purpose, an auxiliary blood flow ABF enters the drive section 4 through an auxiliary blood flow inlet 23 provided at the drive section end DSE. Then, the blood is conveyed by the auxiliary impeller 42 through an auxiliary pump clearance 423 provided between the auxiliary impeller 42 and the inner wall of the pump housing 2. The blood continues to flow into the axial clearance 401 from there. The auxiliary blood flow ABF enters the radial clearance 241 from the axial clearance 401. An auxiliary blood flow outlet 24 is provided at the radially outer end of the radial clearance 241. The auxiliary blood flow ABF flows in the axial clearance 401 in a direction opposite to the pumping direction of the primary and secondary impellers 31, 32. The auxiliary blood flow ABF within the drive section 4 also flows in the opposite direction to the general blood flow GBF flowing around the blood pump 1.

[0064] Reference Figure 3 The enlarged view shows that the rotor bearing ring 43 surrounds the auxiliary impeller 42. The auxiliary impeller 42 includes auxiliary impeller blades 421. The auxiliary impeller blades 421 protrude toward the drive portion end DSE of the pumping device 11 in the direction of the rotation axis 10. A radial rotor bearing 47 is disposed at the drive portion end DSE and includes an outer rotor bearing surface 4211 and an inner rotor bearing surface 4311, with an axially extending bearing clearance between them. The outer rotor bearing surface 4311 is disposed on the rotor bearing ring 43. Blood delivered by the auxiliary impeller 42 flows through the bearing clearance and further flows to the axial clearance 401 between the rotor 41 and the stator 40. Blood flows from the axial clearance 401 to the radial clearance 241. The radial clearance 241 extends between the tapering portion 314 of the primary impeller 31 and the stator 40. An auxiliary blood flow outlet 24 is disposed at the transition between the radial clearance 241 and the periphery of the pumping device 11. The auxiliary blood flow outlet 24 is configured perpendicular to the rotation axis 10. Here, blood from the auxiliary blood flow ABF merges with the pumped blood flow PBF from pump section 2 and the surrounding general blood flow GBF. As shown, when the auxiliary blood flow outlet 24 is positioned close to the outer diameter of the pump housing 2 and close to the primary blood flow outlet 22, the pumped blood flow PBF and the general blood flow GBF support the extraction of blood from the radial gap 241 due to their flow velocities. This enhances the auxiliary blood flow ABF through the axial gap 401.

[0065] The rotation axis 10 extends through the center of the auxiliary impeller 42, and a ridge 422 is provided on the side of the auxiliary impeller 42 opposite to the rotor 41. A bearing pin 44 is provided on the rotation axis 10 in the direction toward the drive section end DSE and adjacent to the ridge 422. The bearing pin 44 is connected to the pump housing 2. The axial bearing surface of the bearing pin 44 toward the auxiliary impeller 42 has a convex shape. The rotation axis 10 passes through the apex of the axial bearing surface of the bearing pin 44 and through the apex of the axial bearing surface of the ridge 422. In this way, the bearing pin 44 interacts with the ridge 422 to form a thrust bearing so as to transmit axial force about the rotation axis between the ridge 422 and the bearing pin 44, wherein the aforementioned parts can rotate relative to each other. Obviously, a smaller contact surface results in less rotational friction.

[0066] The drive section of the blood pump 1 includes one or more, preferably three, auxiliary inlet holes 231. The auxiliary inlet holes 231 extend from the auxiliary blood flow inlet 23 to the auxiliary impeller cavity 232, in which the auxiliary impeller 42 is disposed. Therefore, blood flows from the auxiliary blood flow inlet 23 to the auxiliary impeller 42 via the auxiliary inlet holes 231.

[0067] At least one through-hole 25 is provided at the end DSE of the drive portion of the pumping device 11. The through-hole 25 extends from the conduit 5 to the stator 40. Preferably, three through-holes 25 are provided around the axis of rotation 10. One through-hole 25 may be provided between the two auxiliary inlet through-holes 231. At least one supply wire 51, 52 and / or 53 may extend from the through-hole 25 to connect to the stator 40. Preferably, as shown, the supply wires 51, 52 and / or 53 extend through the interior of the conduit 5 to the exterior of the patient's body. The supply wires 51, 52 and / or 53 extend from the conduit 5 to the stator 40 without contacting the blood.

[0068] Figure 4 A front perspective view of the pump section end PSE of pump section 3 is shown. As shown, the secondary impeller 32 is disposed inside the impeller bearing ring 27. The impeller bearing ring 27 is disposed inside the inflow separator 26. As an alternative to this embodiment, the additional impeller bearing ring 27 can be omitted, such that the outer impeller bearing surface 277 is formed by the inflow separator 26. Here, the inflow separator 26 is mounted between the primary blood flow 1BF and the secondary blood flow 2BF by three supports 28. The secondary blood flow 2BF is shown flowing into the secondary impeller 32 through the secondary blood flow inlet 212, which is disposed to flow into the impeller bearing ring 27. In the secondary impeller 32, blood flows along the secondary impeller channel 321 and through the through opening 315 to the secondary blood flow outlet 213. Here, the secondary blood flow 2BF merges with the primary blood flow 1BF to form the pumped blood flow PBF.

[0069] Figure 5The pump section end PSE of pump section 3 is shown in perspective, with pump housing 2 shown in a transparent manner. A through opening 315 and a secondary blood flow outlet 213 are provided between the two primary impeller blades 313. As shown, the support 28 is connected by an outer support connecting ring 29. The support connecting ring 29 is disposed within the inner circumferential surface of pump housing 2 at the pump section end PSE. Impeller bearing ring 27 is supported by the support 28. It is conceivable that the support connecting ring 29 and the support 28 are manufactured as a single unit. Preferably, the impeller bearing ring 27 is also part of this component. This component can also be integrally formed with pump housing 2.

[0070] Figure 6 A perspective view of the pump section end PSE of pump section 3 is shown, in which the connection with the pump section is shown in a transparent manner. Figures 3 to 5 The illustrated embodiment features a different pump housing 2, with the inflow separator 26 including at least one cutout 261, preferably three, at its downstream end. The cutout 261 is positioned between two supports 28. An impeller bearing ring 27 is part of or fixedly connected to the inflow separator 26, and the cutout 261 also extends through the impeller bearing ring 27. As the secondary impeller rotates, the cross-section of the secondary impeller passage 321 increases when aligned with the cutout 261. The secondary impeller 32 extends, at most, within the impeller bearing ring 27 towards the pump section end PSE at one end of the cutout 261. This has the effect that, during operation, the edge of the cutout 261 extends on the inner impeller bearing surface 327 due to the engagement portion of the rotation axis towards the thrust bearing surface 328, removing blood clots at the onset of their formation, or preferably preventing blood clot formation, because the engagement portion of the rotation axis towards the thrust bearing surface 328 is in direct blood contact at the cutout 261. This helps to prevent blood stagnation within the axial thrust bearing. Figure 7 As shown, the inner impeller bearing surface 327 also has an edge 325, which has the function of removing blood clots from the outer impeller bearing surface 277.

[0071] Figure 7The secondary impeller 32 is shown in detail in perspective view. Here, the secondary impeller 32 is configured as an insert and is generally cylindrical in shape. It can be made of a different material than the primary impeller 31, for example, ceramic. The insert includes a cylindrical portion 323 disposed inside the secondary impeller cavity 312 of the primary impeller 31. A circumferential protrusion 329 forms an axial stop for the secondary impeller 32 in the secondary impeller cavity 312. An inner impeller bearing surface 327 is disposed on the outer circumference of the secondary impeller 32. Two secondary impeller channels 321 are provided at the end of the secondary impeller 32 facing the pump section end PSE. The secondary impeller channels 321 have the largest cross-section at the upstream end of the secondary impeller 32. Therefore, the cross-section of the channels 321 decreases away from the blood inlet 21. Here, when blood flows through the secondary impeller channels 321, the blood flows from the main axial direction in the axial-radial direction.

[0072] The secondary impeller channel 321 is asymmetrically arranged relative to the rotation axis 10 of the secondary impeller 32. At the end of the secondary impeller 32 pointing towards the blood inlet 21, the rotation axis 10 extends through one of the secondary impeller channels 321. Here, the center of rotation on the rotation axis 10 does not coincide with the solid portion of the secondary impeller 32. This has the advantage of blood pooling at the center of rotation, avoiding the situation where there is no velocity difference with the surrounding blood flow.

[0073] An edge 325 is provided at the transition between the secondary impeller passage 321 and the inner impeller bearing surface 327. As described above, this edge 325 is used to push away blood clot formation on the outer impeller bearing surface 277. The inner impeller bearing surface 327 provides the inner surface of a radial bearing at the pump section end PSE. The secondary impeller 32 also includes an axial impeller bearing surface 328, which is provided at the circumferential protrusion 329. The axial impeller bearing surface 328 forms part of the aforementioned axial stop or axial thrust bearing. The axial stop can be configured as an axial bearing capable of transmitting force from the secondary impeller 32 to the bearing ring 27 during impeller rotation.

[0074] Figure 8 An enlarged view of the impeller bearing ring 27 is shown. An outer impeller bearing surface 277 is disposed inside the impeller bearing ring 27. The impeller bearing ring 27 includes an axial bearing ring surface 278. As shown, the axial bearing ring surface 278 may be disposed at the axial end of the impeller bearing ring 27.

[0075] Figure 9 A perspective view of an impeller bearing ring 27 according to another embodiment is shown, which is related to... Figure 8 The illustrated embodiment differs in that it includes a cutout 261, as previously described, located at the downstream end of the impeller bearing ring 27. The number of cutouts 261 is preferably matched to the number of supports 28.

[0076] Figure 10 A cross-sectional perspective view of the drive section end DSE through the drive section 4 is shown. As shown, the auxiliary blood flow ABF enters the pump housing 2 at the auxiliary blood flow inlet 23. The auxiliary impeller 42 accelerates the blood, which continues to flow into the axial gap 401. As indicated by the arrow ABF within the axial gap 401, the blood does not flow directly in the direction of the rotation axis 10, but has a strong circumferential flow component, causing the blood to flow in a spiral along the axial gap 401.

[0077] Figure 11 shows a perspective view of the end of rotor 41 at the drive section end DSE of pumping device 11. The auxiliary blades 421 of the auxiliary impeller 42 are clearly identifiable, and they extend straight radially. The auxiliary impeller blades 421 provide the inner rotor bearing surface 4211 of the radial rotor bearing 47 on their outer circumference. Furthermore, each auxiliary impeller blade 421 has a chamfer 4212. This chamfer 4212 facilitates the formation of... Figure 10 The pumping device 11 shown has a tapered drive section end DSE. Furthermore, the auxiliary impeller blade 421 includes a radially extending end face 4214 at the axial end of the secondary impeller 42. A ridge 422 is formed at the center of the axial end of the secondary impeller 42. The ridge 422 interacts with the bearing pin 44, as... Figure 10 As shown.

[0078] Figure 11A A rotor bearing ring 43 is also shown, which is disposed around the inner rotor bearing surface 4211 of the secondary impeller 42. The outer rotor bearing surface 4311 of the rotor bearing ring 43, together with the inner rotor bearing surface 4211 of the auxiliary impeller 42, forms a rotor bearing 47. The auxiliary impeller 42 has an axial length L and a diameter D. Alternatively, as... Figure 11B As shown, the rotor bearing ring 43 may have a cutout, the shape, function and arrangement of which are similar to the cutout 261 of the impeller bearing ring 27 described above.

[0079] Figure 12 A perspective view shows one end of the rotor 41 connected to the tapering portion 314 of the primary impeller 31. A third-stage impeller 242 is disposed between the tapering portion 314 and the pump portion end of the rotor 41, and extends radially from the outer diameter of the rotor 41 to the outer diameter of the tapering portion 314 to form a shoulder. The axial plane of this shoulder forms a rotatable wall 2411 of the radial clearance 24. The third-stage impeller blades 2412 protrude from the rotatable wall 2411 toward the drive portion end DSE of the pumping device 11. Preferably, the third-stage impeller blades 2412 extend axially along the axis of rotation 10. In particular, the third-stage impeller blades 2412 are straight and extend radially relative to the axis of rotation 10. Alternatively, the third-stage impeller blades 2412 may be omitted.

Claims

1. An intravascular blood pump (1), comprising a pumping device (11) having a pump portion (3) and a drive portion (4), wherein, —The pump section (3) includes a pump housing (2) having a primary blood flow inlet (211) and a primary blood flow outlet (22) hydraulically connected by a primary passage (30), and the drive section (4) includes a stator (40) and a rotor (41) rotatable about a rotation axis (10) and configured to rotate a primary impeller (31) that is configured to deliver primary blood flow (PBF) from the primary blood flow inlet (211) to the primary blood flow outlet (22) along the primary passage (30). The drive section (4) also includes an auxiliary blood flow inlet (23) and an auxiliary blood flow outlet (24), which are hydraulically connected by an auxiliary passage extending through the axial gap (401) between the rotor (41) and the stator (40) and an auxiliary impeller (42) disposed at the drive section end (DSE) of the rotor (41) and rotatable together with the rotor (41) about the rotation axis (10). The auxiliary impeller (42) includes one or more auxiliary impeller blades (421). Or multiple auxiliary impeller blades (421) are configured to deliver auxiliary blood flow (ABF) from the auxiliary blood flow inlet (23) to the auxiliary blood flow outlet (24) along the auxiliary passage toward the pump portion end (PSE) of the pumping device (11), wherein the auxiliary blood flow outlet (24) is located outside the primary passage (30), wherein the auxiliary blood flow (ABF) is separated from the primary blood flow (PBF) such that blood delivered via the auxiliary passage mixes only with blood from the primary passage (30) outside the primary passage (30). —The rotor (41) is mounted in a blood-cleansing radial sliding rotor bearing (47), which has an inner rotor bearing surface (4211) and an outer rotor bearing surface (4311), and —The auxiliary impeller (42) is a radial or radial-axial conveying impeller and forms the inner rotor bearing surface (4211) of the radial sliding rotor bearing (47).

2. The intravascular blood pump as claimed in claim 1, wherein the inner rotor bearing surface (4211) and the rotor (41) have a common outer diameter.

3. The intravascular blood pump as claimed in claim 1 or 2, wherein each of the auxiliary impeller blades (421) has an outer peripheral surface, and wherein the inner rotor bearing surface (4211) is formed by the outer peripheral surfaces of at least two of the auxiliary impeller blades (421).

4. The intravascular blood pump as claimed in claim 1 or 2, wherein at least one of the auxiliary impeller blades (421) protrudes axially from the auxiliary impeller (42).

5. The intravascular blood pump as claimed in claim 1 or 2, wherein at least one of the auxiliary impeller blades (421) extends radially from the auxiliary blood inlet (23) to at least the axial gap (401).

6. The intravascular blood pump as claimed in claim 1 or 2, wherein at least one of the auxiliary impeller blades (421) extends in a radial direction relative to the axis of rotation (10).

7. The intravascular blood pump as claimed in claim 1 or 2, wherein at least one of the auxiliary impeller blades (421) forms an auxiliary pump gap (423) with the inner wall of the pump housing (2).

8. The intravascular blood pump as claimed in claim 1 or 2, wherein each of the auxiliary impeller blades (421) has an outer peripheral surface, and wherein the outer peripheral surfaces of at least two of the auxiliary impeller blades (421) are inclined in a radial direction to form a hydrodynamic radial sliding rotor bearing (47).

9. The intravascular blood pump of claim 1 or 2, wherein the inner rotor bearing surface (4211) includes a radially projecting protrusion, the apex of which extends in the circumferential direction.

10. The intravascular blood pump as claimed in claim 1 or 2, wherein the inner rotor bearing surface (4211) is made of ceramic material.

11. The intravascular blood pump of claim 10, wherein the auxiliary impeller (42) is a single piece of ceramic material.

12. The intravascular blood pump as claimed in claim 1 or 2, wherein a portion of the outer rotor bearing surface (4311) forming the radial sliding rotor bearing (47) in the pumping device (11) is a rotor bearing ring (43).

13. The intravascular blood pump of claim 12, wherein the outer rotor bearing surface (4311) is made of ceramic material.

14. The intravascular blood pump of claim 13, wherein a portion of the pumping device (11) forms the surface of the outer rotor bearing.

15. The intravascular blood pump as claimed in claim 1 or 2, comprising an axial rotor bearing having an axial rotor bearing surface or an axial radial rotor bearing having an axial radial rotor bearing surface, disposed at the auxiliary impeller (42).

16. The intravascular blood pump of claim 15, wherein at least the axial rotor bearing surface or the axial-radial rotor bearing surface of the auxiliary impeller (42) is made of ceramic material.

17. The intravascular blood pump of claim 10, wherein the ceramic material is silicon carbide.

18. The intravascular blood pump as claimed in claim 1 or 2, wherein the axial length of the auxiliary impeller (42) is less than the maximum outer diameter of the auxiliary impeller (42).

19. The intravascular blood pump as claimed in claim 1 or 2, wherein the primary impeller (31) and the auxiliary impeller (42) are disposed on opposite sides of the rotor (41).

20. The intravascular blood pump of claim 1 or 2, wherein the radial outer edge of one or more of the auxiliary impeller blades (421) is chamfered.

21. The intravascular blood pump as claimed in claim 1 or 2, wherein the auxiliary blood flow inlet (23) includes a plurality of auxiliary inlet through holes (231) disposed around the axis of rotation (10).

22. The intravascular blood pump of claim 21, wherein, In the space between the two auxiliary inlet through holes (231), a line channel (25) for the power supply lines (51, 52, 53) of the drive section (4) is provided.

23. The intravascular blood pump of claim 21, wherein, The axial gap (401) has an inlet configured to allow blood to flow into the axial gap (401), wherein the inner end (233) of the auxiliary inlet through hole (231) is configured to be radially further inward than the radial innermost part of the inlet into the axial gap (401).

24. The intravascular blood pump as claimed in claim 1 or 2, wherein the pumping device (11) includes a three-stage impeller (242) configured to draw the auxiliary blood flow through the auxiliary passage.

25. The intravascular blood pump of claim 24, wherein the third-stage impeller (242) is rotatable together with the rotor (41) about the axis of rotation (10).

26. The intravascular blood pump as claimed in claim 1 or 2, wherein the auxiliary blood flow outlet (24) is disposed at the radial gap (241) between the primary impeller (31) and the stator (40).

27. The intravascular blood pump of claim 26, wherein the auxiliary blood flow outlet (24) is configured such that, in operation, the pumped blood flow (PBF) exiting the primary blood flow outlet (22) passes through the auxiliary blood flow outlet (24).

28. The intravascular blood pump of claim 26, wherein the rotatable wall (2411) of the radial clearance (241) is rotatable together with the rotor (41).

29. The intravascular blood pump of claim 28, wherein the fixed wall (2410) of the radial gap (241) opposite to the rotatable wall (2411) of the radial gap (241) is mechanically connected to the stator (40).

30. The intravascular blood pump of claim 24, wherein the auxiliary blood flow outlet (24) is disposed at the radial gap (241) between the primary impeller (31) and the stator (40), wherein the tertiary impeller (242) is disposed in the radial gap (241).

31. The intravascular blood pump of claim 25, wherein the auxiliary blood flow outlet (24) is disposed at the radial gap (241) between the primary impeller (31) and the stator (40), wherein the tertiary impeller (242) is disposed in the radial gap (241).

32. The intravascular blood pump of claim 30 or 31, wherein the rotatable wall (2411) of the radial clearance (241) is rotatable together with the rotor (41), wherein the third-stage impeller (242) includes at least one third-stage impeller blade (2412) projecting from the rotatable wall (2411) of the radial clearance (241).

33. The intravascular blood pump as claimed in claim 30 or 31, wherein the inflow toward the third-stage impeller (242) is disposed at the outflow end of the axial gap (401).

34. The intravascular blood pump of claim 11, wherein the ceramic material is silicon carbide.

35. The intravascular blood pump of claim 13, wherein the ceramic material is silicon carbide.

36. The intravascular blood pump of claim 16, wherein the ceramic material is silicon carbide.

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