Blood pump

Abstract

A blood pump (1) comprising a pump housing (2) having a blood flow inlet (5) and a blood flow outlet (6) connected by a passageway (7), and an impeller (3) arranged in the pump housing (2) rotatable about an axis of rotation (9). The impeller (3) is provided with blades (4) sized and shaped to convey blood along the passageway (7) from the blood flow inlet (5) to the blood flow outlet (6), the impeller (3) being rotatably supported in the pump housing (2) by at least one contact type bearing (20) comprising a bearing surface of the impeller (3) facing a bearing surface of the pump housing (2). At least one flushing channel (30) extends through the impeller (3) and is in fluid communication with the passageway (7) via a first opening (34) and with the bearing (31) via a second opening (35). The flushing channel (30) is operatively associated with a secondary pump for pumping blood through the flushing channel (30) towards the bearing (20), wherein the secondary pump is at least partially formed by the at least one flushing channel (30) extending through the impeller (3) in a direction having at least one tangential portion.

Description

[0001] Divisional application

[0002] This application is a divisional application of divisional application No. 202010520897.6, the original application of which is patent application No. 201680015452.4, with an international filing date of March 16, 2016, and an entry date into the Chinese national phase of September 13, 2017, entitled "Blood Pump". Background Technology

[0003] This invention relates to a blood pump to be implanted in a patient to support the patient's heart. In particular, the blood pump can be used as a "bridge to healing," thereby temporarily supporting the patient's heart until the patient's heart has been fully healed.

[0004] Different types of blood pumps are known, such as axial blood pumps, centrifugal blood pumps, or hybrid blood pumps where blood flow is caused by both axial and radial forces. Blood pumps can be inserted into a patient's blood vessel, such as the aorta, via a catheter, or can be placed in the chest cavity. A blood pump typically comprises a pump housing having a blood inlet and a blood outlet connected by a passageway. To induce blood flow along said passageway from the blood inlet to the blood outlet, an impeller is rotatably supported within the pump housing, and the impeller is provided with blades for delivering blood.

[0005] The impeller is supported within the pump housing by means of at least one bearing. Depending on the intended use of the blood pump—for example, whether it is intended for short-term use (hours or days) or long-term use (weeks or years)—the bearing can be of different types. Various types of bearings are known, such as contact bearings and non-contact bearings. In non-contact bearings, the bearing surfaces do not contact each other; for example, in a magnetic bearing, the bearing surfaces are “suspended” due to repulsive magnetic forces. Generally, contact bearings can include all types of bearings in which the bearing surfaces can be at least partially in contact at any time during pump operation (i.e., always or intermittently), such as in sliding bearings, pivot bearings, hydrodynamic bearings, hydrostatic bearings, ball bearings, etc., or any combination thereof. In particular, contact bearings can be “blood-immersed bearings,” where the bearing surfaces are in contact with blood. Contact bearings can be heated during use and subjected to mechanical wear due to the contact between the rotating and stationary bearing surfaces during pump operation. It is desirable to provide a cooling fluid, such as blood itself, to the bearing. In non-contact bearings, the bearing surfaces do not have physical contact but are separated by gaps that communicate with passages or other fluid supply fluids. Similarly, other gaps between the impeller and the pump housing should be flushed to prevent blood clotting and clots, for example, at the downstream front surface of the impeller.

[0006] U.S. Patent 2011 / 0238172A1 exemplarily discloses an arrangement for cleaning gaps or bearing surfaces within a blood pump. A flushing channel extends through an impeller and is in fluid communication with a passage via a first opening and with a gap via a second opening. Pressure distribution in the pump housing, where pressure increases downstream along the impeller, causes blood flow through the gap and flushing channel. Blood enters the gap at the downstream end of the impeller and flows through the flushing channel toward a lower pressure area in the passage. This flushing flow has the disadvantage of relying on the impeller's rotational speed because a pressure differential must be generated to cause blood flow. Other forces, such as centrifugal force and the reverse force due to the flushing flow in the rearward direction, must also be overcome. In another embodiment disclosed in U.S. Patent 2011 / 0238172A1, the impeller is supported in the pump housing by a hydrodynamic bearing, and the inlet opening of the flushing channel is located at the upstream end of the impeller. Secondary blades located at the downstream end of the impeller are configured to cause flushing flow through the flushing channel and gap in a direction from a low-pressure area to a high-pressure area. Summary of the Invention

[0007] Therefore, the initial object of the present invention is to provide a blood pump in which blood flow stagnation, blood coagulation, and blood clots can be effectively avoided in the gaps between the rotating and stationary parts of the blood pump, particularly between the stationary and rotating parts of the bearing or between the impeller and the pump housing, especially, this effect is independent of the pump's rotational speed or operating state. A further object of the present invention is to provide a blood pump that allows for effective cooling of contact bearings. A further object of the present invention is to provide a blood pump in which gaps can be effectively flushed.

[0008] According to the present invention, the initial purpose is achieved by a blood pump having the features of independent claim 1. Preferred embodiments and further developments of the invention are specified in the dependent claims above claim 1.

[0009] Similar to known blood pumps, the blood pump according to the present invention includes a pump housing having a blood inlet and a blood outlet connected by a passage. The pump housing can be understood as constituting the entire stationary part of the blood pump. An impeller or rotor is arranged in the pump housing to be rotatable about an axis of rotation, which may be the longitudinal axis of the impeller, wherein the impeller is provided with blades, the size and shape of which are designed to transport blood along the passage from the blood inlet to the blood outlet. The impeller is rotatably supported in the pump housing by at least one contact bearing, preferably a pivot bearing, the at least one contact bearing including a bearing surface of the impeller facing the pump housing.

[0010] At least one flushing channel extends through the impeller and is in fluid communication with the passage via a first opening and with the bearing via a second opening. To induce flushing flow, which may also be referred to as active flushing flow, the flushing channel is operatively associated with a secondary pump for pumping blood toward the bearing through the flushing channel. According to the invention, the secondary pump is formed at least partially by said at least one flushing channel extending through the impeller in a direction having at least one tangential portion. In other words, the secondary pump is specifically formed at least partially by said at least one flushing channel itself, the size, shape, and arrangement of which are designed to pump blood toward the bearing through the flushing channel. Compared to an arrangement without an active pumping device toward the bearing, the cleaning of the contact bearing and thereby the cooling of the bearing can be improved by providing a secondary pump that induces active flushing flow. A suitable pressure distribution within the pump can support the secondary pump, which will be described in more detail below. However, it will be appreciated that the use of the secondary pump is independent of the pressure distribution within the pump.

[0011] Active flushing flow is particularly useful for cooling contact bearings or "blood-immersed bearings" because the amount of blood delivered to the bearing to flush and cool it is increased compared to a pump without a secondary pump. Bearing cooling can be further improved by effectively dissipating heat from the bearing surface. For this purpose, the bearing can include a high thermal conductivity material, such as stainless steel, which dissipates heat better than, for example, ceramic or aluminum. Advantageously, bearings are configured with at least two components, particularly bearing surfaces made of a smooth, wear-resistant material such as ceramic, for example, provided in the form of a ceramic cap, while a portion of the bearing furthest from the bearing surface is made of a high thermal conductivity material such as stainless steel.

[0012] In one embodiment, the flushing channel may extend linearly through the impeller and deviate relative to the axis of rotation. Specifically, the flushing channel may extend along a plane parallel to the axis of rotation. By providing an arrangement of flushing channels that are linear and deviate from the axis of rotation, i.e., do not coincide with it, active flushing flow through the flushing channels can be achieved.

[0013] In another embodiment, the flushing channel may be curved and extend from the first opening in the direction about the axis of rotation, particularly in a helical shape. A helical shape can be understood as any curved, spiral, helical, or otherwise curved shape of any length along the direction about the axis of rotation. Such a shape is advantageous because it supports active flushing flow toward the bearing.

[0014] Preferably, the flushing channel extends from the first opening at an angle relative to the impeller surface in a circumferential direction opposite to the direction of rotation. Specifically, unlike a flushing channel extending perpendicular to the impeller surface, an angled inflow opening promotes blood entry into the flushing channel and increases the flow rate through it. This effect can be further enhanced by selecting a suitable angle. For example, the angle can be less than 20°, preferably less than 15°, and more preferably less than 10°. The flushing channel can extend from the first opening relative to the impeller surface in a substantially tangential direction; in other words, it extends at a very small angle relative to the impeller surface. However, it is important that this angle is in a circumferential direction opposite to the direction of rotation; that is, it is important that the first opening opens in the direction of rotation to increase the amount of blood flowing through the flushing channel compared to an arrangement of flushing channels perpendicular to the impeller surface.

[0015] In one embodiment, the distance between the second opening and the axis of rotation can be less than or equal to the distance between the first opening and the axis of rotation. In other words, in the downstream direction, the flushing channel extends toward the axis of rotation. Preferably, the distance between the first opening and the axis of rotation should be as small as possible to reduce the centrifugal force that the flushing flow must overcome within the flushing channel. In other words, the distance between the first opening and the second opening in the radially inward direction should be as small as possible. More preferably, the distance between the axis of rotation and the first opening is much smaller than the distance between the axis of rotation and the gap transition point; for example, the distance between the axis of rotation and the first opening is less than half (50%) or less than half the distance between the axis of rotation and the point where the flushing flow exits the passage, less than 40% or even less than 30% of the distance between the axis of rotation and the gap transition point. This arrangement can be improved in centrifugal blood pumps compared to axial blood pumps or hybrid blood pumps, i.e., the distance between the first opening and the point where the flushing flow exits the passage can be increased.

[0016] The impeller may include a central opening extending along the axis of rotation and accommodating a bearing, wherein a second opening is in fluid communication with the central opening. Furthermore, a flushing passage is directed substantially radially toward the axis of rotation at the second opening. This improves bearing cleaning, thereby improving bearing cooling.

[0017] Preferably, the first opening of the flushing channel is positioned on the forward side of the blade (generally referred to as the positive pressure side of the blade) adjacent to one of the blades of the impeller, relative to the direction of rotation. In this region, the pressure is higher, particularly compared to the region on the rearward side of the blade (generally referred to as the negative pressure side of the blade), which allows for improved flushing flow towards the bearing through the flushing channel. In one embodiment, the first opening may be located on the forward side of the blade, while the second opening may be located on the rearward side of the blade; that is, both openings are located on the radially outer surface of the impeller, and the flushing channel extends below and through the blade. In another embodiment, the flushing channel may extend within the blade, whereby the first opening is located on the forward side of the blade, and the second opening is located within the blade, particularly on the radially outer edge of the blade. It should be understood that the flushing channel is in fluid communication with the area to be flushed.

[0018] As explained, the performance or output of the secondary pump can be improved by a specific arrangement of the flushing channel through the impeller, such as a linear or curved flushing channel extending at an angle relative to the impeller surface. The performance of the secondary pump can be further improved by the cross-section of the first opening of the flushing channel. The cross-section of the first opening can be circular or non-circular. Having a circular cross-section and extending at an angle relative to the impeller surface results in a non-circular cross-section, such as an elliptical cross-section. In one embodiment, the first opening can be formed by an end of the flushing channel that is at least partially exposed due to the inclination of the flushing channel relative to the impeller surface. In other words, the first opening can be on the impeller surface and is elongated, which can further increase the amount of blood entering the flushing channel during operation of the blood pump.

[0019] In another embodiment, the protrusion extends into the first opening of the flushing channel, and its size and shape are designed to increase blood flow into the flushing channel through the first opening, particularly compared to the cross-section of the first opening without the protrusion. The first opening without the protrusion can be circular or non-circular. The protrusion can be positioned rearward of the first opening relative to the direction of rotation, thus acting as a "wing" to facilitate blood inflow into the first opening and thereby improve the performance of the secondary pump. Optionally or additionally, the impeller may include a wing that extends radially from the impeller and is positioned adjacent to and after the first opening of the flushing channel relative to the direction of rotation. Preferably, the wing extends over the first opening of the flushing channel and opens in the direction of rotation to allow blood to enter the first opening. The wing forms a pocket that collects blood and guides the collected blood into the first opening during the rotation of the impeller. To achieve a similar effect, the impeller may include a protrusion constituting the first opening, such that the cross-section of the first opening extends at an angle relative to the surface of the impeller, preferably greater than 45°, more preferably 90°, and opens in the direction of rotation. This can significantly increase the amount of blood flowing into the flushing channel.

[0020] Preferably, the blood pump includes two or more of the aforementioned flushing channels arranged symmetrically with respect to the axis of rotation. In particular, the blood pump may include two, three, four, five, or six flushing channels.

[0021] In addition to the size, shape, and arrangement of the flushing passage that forms at least a portion of the secondary pump, the secondary pump may further include grooves or blades formed in the surface of the impeller. Such secondary grooves or blades may be disposed on the downstream front surface of the impeller to support blood flow toward the bearing through the flushing passage.

[0022] In one embodiment, the impeller may have a portion extending radially outward in a downstream direction, in which a first opening of the flushing passage is disposed. Specifically, the portion tapers radially outward in a tapered manner in the downstream direction. The portion may be integrally formed with the impeller or formed separately. By arranging the first opening in the radially extending portion of the impeller, such that the first opening is guided in a direction opposite to the primary direction of blood flow through the passage, the performance of the secondary pump can be further enhanced. The first opening can thus capture more blood and improve the performance of the secondary pump. Impeller blades may extend above the portion.

[0023] In a preferred embodiment, the first opening of the flushing channel is arranged in a region of the impeller that is under higher pressure than the second opening during pump operation, resulting in blood flow from the first opening through the flushing channel to the bearing. In other words, the flushing flow is directed in a "forward" direction, i.e., towards the blood outlet of the pump housing, because the first opening of the flushing channel, i.e., the inlet opening of the flushing channel, is located in the high-pressure region of the impeller, while the pressure is lower on the downstream side of the impeller. Therefore, by utilizing this pressure difference that occurs during the operation of the blood pump, particularly the local pressure gradient within the flushing channel, a forward flushing flow can be generated. This has the advantage that the necessary pressure difference exists at all times during pump operation, independent of rotational speed and operating conditions (e.g., before loading, after loading, the magnitude of the initial forward flow), particularly at the beginning of operation, when the impeller rotation begins and the rotational speed is low, especially below the design speed of the blood pump. Conversely, in known blood pumps, the flushing flow is directed in a "backward" direction, requiring the establishment of a pressure difference, which takes time during which the flushing flow is slow or may be stagnant. This can lead to blood coagulation and clots, either in the gaps, in the flushing channels, or both simultaneously. Furthermore, the backward flow must overcome the forces resulting from the dominant flow direction, which can also cause the flushing flow to become stagnant, thus leading to blood coagulation and clots. According to the invention, specifically, by utilizing the pressure distribution within the pump housing during pump operation, the flushing flow is consistently in a "forward" direction throughout the operation of the blood pump.

[0024] The first opening of the flushing passage can be located in the downstream half of the impeller. During pump operation, the pressure increases along the length of the impeller, particularly in the region where the impeller blades are located. Therefore, the pressure in the downstream half of the impeller is higher than that in the upstream half. Because the first opening of the flushing passage is preferably at a high pressure, it is preferable to locate the first opening in the downstream half of the impeller. More preferably, the first opening can be located in the downstream third, downstream quarter, or downstream fifth of the impeller. In particular, it is advantageous to locate the first opening as close as possible to the downstream end of the impeller, for example, in the last 10% of the impeller's length in the downstream direction.

[0025] Regarding pressure distribution, preferably, the first opening of the flushing passage is located in the impeller in a region where the pressure during operation of the blood pump is greater than the average pressure distribution along the length of the impeller disposed in the passage; more preferably, the pressure is substantially the maximum pressure. The high pressure difference between the first and second openings of the flushing passage improves the flushing flow from the first opening of the flushing passage to the bearing. In particular, the high pressure difference is advantageous for supporting the secondary pump. Attached Figure Description

[0026] The foregoing invention and the following specific embodiments of preferred embodiments can be better understood by reading in conjunction with the accompanying drawings. Reference numerals have been used in the drawings to illustrate this disclosure. However, the scope of this disclosure is not limited to the specific embodiments disclosed in the drawings. In the drawings:

[0027] Figure 1 A cross-sectional view of a blood pump for extracardiac use according to the present invention is shown.

[0028] Figure 1A A cross-sectional view of another blood pump for extracardiac use according to the present invention is shown.

[0029] Figure 2 A cross-sectional view of a blood pump designed as a catheter pump according to the present invention is shown.

[0030] Figure 3 A three-dimensional view of the impeller is shown.

[0031] Figures 4a to 4d Different views of a portion of the impeller are shown.

[0032] Figure 5a and Figure 5b Other embodiments of the impeller are shown.

[0033] Figure 6a and Figure 6b Another implementation of a portion of the impeller is shown.

[0034] Figure 7 A cross-sectional view of a portion of a blood pump according to another embodiment is shown.

[0035] Figure 8 A cross-sectional view of a portion of an impeller according to another embodiment is shown.

[0036] Figure 9 A cross-sectional view of a portion of an impeller according to another embodiment is shown.

[0037] Figure 10 A cross-sectional view of a portion of an impeller according to yet another embodiment is shown.

[0038] Figure 11 A cross-sectional view of a portion of a blood pump according to another embodiment is shown. Detailed Implementation

[0039] refer to Figure 1The diagram shows a cross-sectional view of a blood pump 1. The blood pump is designed for use outside the body, extracardiac, and extracorporeal, and includes a pump housing 2 with a blood inlet 5 and a blood outlet 6. During operation, the pump housing 2 is positioned outside the patient's body, and the blood inlet 5 and blood outlet 6 are connected to their respective connectors (specifically, for inflow from the heart and outflow to the aorta). Figure 2 It shows the relationship with Figure 1 Similar implementation methods, the difference being Figure 2 The embodiment described above is designed as a catheter pump 1'. A blood inlet 5' is located at the end of a flexible cannula 50, which, during use, is configured to pass through a heart valve, such as the aortic valve, while a blood outlet 6' is located on one side of the pump housing 2' and within a cardiac vessel, such as the aorta. The blood pump 1' is connected to a catheter 51, and a wire 52 extends through the catheter 51 to drive the pump 1'. The blood pump 1 and the blood pump 1' function in the same manner. It will be appreciated that all the features described below are applicable to both embodiments described above.

[0040] Blood is transported along a passage 7 connecting the blood inlet 5 and the blood outlet 6. An impeller 3 is configured to transport blood along the passage 7 and is rotatably mounted within a pump housing 2 about a rotation axis 9 by means of a first bearing 10 and a second bearing 20. Preferably, the rotation axis is the longitudinal axis of the impeller 3. Both bearings 10 and 20 are contact bearings. However, at least one of bearings 10 and 20 can be a non-contact bearing, such as a magnetic bearing or a hydrodynamic bearing. The second bearing 20 is a pivot bearing having a spherical bearing surface that allows rotational movement as well as pivoting movement at an angle. The first bearing 10 is disposed in a support member 15 to stabilize the rotation of the impeller 3, the support member 15 having at least one opening 16 for blood flow. Blades 4 are disposed on the impeller 3 to transport blood as the impeller 3 rotates. The rotation of the impeller 3 is caused by a motor stator 8 magnetically coupled to an end 37 of the impeller 3. As those skilled in the art will recognize, other suitable drive mechanisms can be used. The illustrated blood pump 1 is a hybrid blood pump in which the primary direction of flow is axial. It will be recognized that, depending on the arrangement of impeller 3, and especially blades 4, blood pump 1 can also be a purely axial blood pump.

[0041] The impeller 3 includes a portion 33 disposed in the downstream portion of the impeller 3 and extending radially outward. The portion 33 may be referred to as a yoke, flange portion, or end. In this embodiment, the portion 33 includes an outer surface extending at an angle of 45° relative to the axis of rotation 9. Other suitable angles may be selected, such as angles between 30° and 60°, or the portion 33 may be a curved surface. The portion 33 may be integrally formed with the impeller 3 or formed separately as shown in this embodiment. At least one flushing channel 30, preferably two or more, such as three, four, five, or six flushing channels 30 (… Figure 1 (Only one is shown) extending through the impeller 3, particularly through portion 33, to allow flushing or cleaning of the stationary portions of the impeller 3 and the blood pump 1, particularly the pivot bearing 20 and clearance 31 between the impeller 3 and the pump housing 2 or the motor 8, wherein the motor 8 can be considered associated with the pump housing 2. At least one flushing passage 30 may also extend at least partially into the main portion of the impeller 3 outside of portion 33.

[0042] The flushing channel 30 has a first opening 34, or inflow opening, and a second opening 35, or outflow opening. The first opening 34 forms a fluid connection between the passage 7 and the flushing channel 30, while the second opening 35 is fluidly connected to the gap 31. Specifically, the second opening 35 is in fluid communication with the central bore or central opening 32 of the portion 33 that receives the second bearing 20. The gap 31 is fluidly connected to the passage 7 via the gap transition point 36, i.e., the location where the gap 31 opens into the passage 7.

[0043] The first opening 34 of the flushing passage 30 is located in the downstream half of the impeller 3. Specifically, the first opening 34 is located in the high-pressure region of the impeller 3 caused by the rotation of the impeller 3 during operation of the blood pump 1. In particular, the first opening 34 can be located near or in the region of highest pressure within the pump housing 2. The pressure increases due to the blades 4 and the deflection of fluid from the axial flow direction to the radial direction, and then decreases downstream of the blades 4. Therefore, due to the appropriate selection of the location of the first opening 34, i.e., near the downstream end of the impeller 3, the pressure at the gap transition point 36 is lower than the pressure at the first opening 34. This pressure distribution, which can be enhanced by correspondingly selecting the shape of the blades 4, results in a flow direction from the first opening 34 through the flushing passage 30 and the gap 31 to the gap transition point 36. Alternatively, this can be achieved by creating a local pressure drop near point 36 due to the Venturi effect, for example by providing a constriction 53 in the passage 7 (see...). Figure 1A This further reduces the pressure at point 36. In other words, blood flows forward through the flushing channel 30 toward the blood outlet 6 of the pump housing 2. Blood clotting can be effectively prevented at any time during the operation of the blood pump 1, especially at speeds below the design speed of the blood pump 1, because the forward flow flushing can occur at any rotation speed.

[0044] In addition to flushing the pivot bearing 20 and clearance 31, blood flow through the flushing channel 30 provides cooling for the pivot bearing 20. The pivot bearing 20 is arranged in the central opening 32 of the portion 33. Therefore, blood is transported toward the pivot bearing 20 through the flushing channel 30. The pivot bearing 20 can be effectively cooled and cleaned. As will be described in detail below, this effect can be further enhanced by providing a secondary pump that actively pumps blood toward the bearing 20 through the flushing channel 30. While the stated "forward" direction of the flushing flow through the flushing channel 30 is advantageous, the flushing flow can be directed in any direction.

[0045] Now for reference Figure 3 , Figure 3 An embodiment of the impeller 3 is shown. The impeller has blades 4 arranged around the body of the impeller 3, and their size and shape are designed such that, along the direction of rotation of the impeller 3 (in... Figure 3 (Indicated by arrows) Blood is transported during rotation. The impeller 3 has a portion 33 at its downstream end, wherein portion 33 includes a flushing channel 30 with an inflow opening 34. As explained above, the inflow opening 34 is arranged in the high-pressure region of the impeller 3 to ensure that the blood flow through the flushing channel 30 is guided from the first opening 34 or the inflow opening to the second opening 35. In this embodiment, the inflow opening 34 is arranged on the forward side (also referred to as the positive pressure side of the blade) of one of the blades 4 relative to the direction of rotation. In particular, the pressure is higher on the forward side compared to the rearward side of the blade 4 (also referred to as the negative pressure side of the blade), which supports the flow direction into the inflow opening 34 of the flushing channel 30. However, the opening 34 may be arranged on the rearward side of the blade 4, where the pressure can be sufficiently high, since the opening 34 is located in the portion 33 at the downstream end of the impeller 3.

[0046] Figures 4a to 4d A different view of one embodiment of part 33 is shown. In this embodiment, the flushing channel 30 forms a secondary pump that pumps blood from the corresponding first opening 34 to the second opening 35 through the flushing channel 30, then to the central opening 32 and the bearing 20, and then further to the gap transition point 36 (see...). Figure 1 In this embodiment, the flushing channel 30 extends linearly through the impeller 3 and relative to the axis of rotation 9 (in Figure 4b The dashed line in the middle indicates that... Figure 4b(The bottom view of part 33 is shown here.) The flushing channel 30 extends along a plane parallel to the axis of rotation 9, such that the flushing channel 30 extends in a direction having a tangential portion. This arrangement enhances blood flow in the direction from the first opening 34 toward the second opening 35. Two flushing channels 30 are shown in this embodiment. However, it will be appreciated that three, four, or more flushing channels can also be provided, which can be arranged symmetrically about the axis of rotation 9. Figure 4d , Figure 4d For along Figure 4b As can be specifically shown in the cross-sectional view of line BB, the flushing channel 30 is inclined in the downstream direction. The second opening 35, located downstream of the first opening 34, is closer to the axis of rotation 9 than the first opening 34. Figure 1 As shown, the flushing channel 30 opens to a central opening 32 that at least partially accommodates the second bearing 20.

[0047] Figure 5a and Figure 5b Another embodiment of the impeller 3 with a flushing passage 30 forming a secondary pump is shown. According to... Figure 5a In this embodiment, the first opening 34 is not circular. More precisely, a protrusion 38 extends into the first opening 34 to increase the amount of blood flowing into the flushing channel through the first opening 34. The protrusion 38 is arranged rearward relative to the direction of rotation of the first opening 34. The shape of the first opening 34 can be described as kidney-shaped. It acts like an "airfoil," creating traction or suction as the impeller 3 rotates to increase the amount of blood entering the first opening 34, particularly compared to embodiments without the protrusion 38 (such as...). Figure 3 Compared to the previous implementation, the shape of the protrusion 38 can be selected based on the expected amount of blood that should flow through the flushing channel 30. The cross-section of the first opening 34 can be symmetrical or asymmetrical.

[0048] like Figure 5b As shown, the wing 39 can be alternatively provided, or a wing 39 other than the protrusion 38 can be provided. The wing 39 is arranged after the first opening 34 relative to the direction of rotation and forms a pocket to capture a larger volume of blood as the impeller 3 rotates in the direction of rotation. The wing 39 can be provided in embodiments without the wing 39 (such as... Figure 3 The implementation method is suitable for increasing the amount of blood entering the first opening 34 compared to any size and shape. The same effect can be achieved by arranging the first opening 34 in a nose-like portion or protrusion extending radially from the impeller 3 and pointing the first opening 34 in the direction of rotation.

[0049] Now for reference Figure 6a and Figure 6bThe diagram illustrates an embodiment with a portion 33' of a flushing channel 30'. The direction of rotation is indicated by arrows. As in the embodiment described above, the flushing channel 30' has a first opening 34' and a second opening 35' facing the central opening 32'. As described in relation to other embodiments, the flushing channel 30' forms part of a secondary pump to force blood to flow in a direction from the first opening 34' to the second opening 35' toward the second bearing 20. In this embodiment, the flushing channel 30' is curved and extends in a helical shape about the axis of rotation 9. It will be appreciated that the term "helical shape" includes any curved shape, whether it forms a conventional helical shape or any other curved shape having at least one tangential portion. The flushing channel 30' enters the impeller 3 at a small angle at the first opening, such that the first opening 34' is formed by the exposed portion of the flushing channel 30' and has an elongated shape. This facilitates blood capture and helps increase the amount of blood entering the first opening 34', particularly compared to an arrangement where the flushing channel 30 extends to the surface of the impeller 3 at a large angle, such as vertical or substantially vertical. The flushing channel 30' extends in a curved shape toward the central opening 32' and exits in a generally radial direction at the second opening 35'. Blood is effectively pumped into the central opening 32' and then pumped to the second bearing 20, thereby cleaning and cooling the second bearing 20. (As in combination) Figure 1 As explained, the blood flow through the flushing channel 30' effectively flushes the gap 31 between the rotating impeller 3 and the stationary pump housing 2. To further improve the performance of the secondary pump, the secondary pump may further include grooves or blades formed on the surface of the impeller 3, particularly in the gap 31.

[0050] It should be understood that, without the assistance of centrifugal pumping at gap 31, the aforementioned secondary pump cannot overcome the centrifugal force of a rotating channel of any shape extending from a larger diameter to a smaller diameter.

[0051] The performance of the secondary pump can be further enhanced by the position of at least one of the first openings 34 and the gap transition point 36 relative to the axis of rotation 9, particularly the position of at least one of the first openings 34 and the gap transition point 36 relative to each other. Figure 7 As shown, the first opening has a first distance d1 to the axis of rotation 9, while the gap transition point 36 has a second distance d2 to the axis of rotation 9. The performance of the secondary pump can be improved if the first opening 34 is as close to the axis of rotation as possible, that is, if the distance d1 is as small as possible and the flushing channel 30 extends only a short distance toward the axis of rotation 9. This reduces the centrifugal force that must be overcome by the flushing flow flowing in the direction toward the axis of rotation. In particular, it is advantageous for the first distance d1 to be smaller than the second distance; preferably, d1 can be half or less of d2.

[0052] In another section perpendicular to the axis of rotation 9 Figure 8 In the embodiment shown, the impeller 3 includes a flushing channel 40 with a first opening 41 and a second opening 42 disposed on the radially outer surface of the impeller 3. The first opening 41 is relative to the direction of rotation (in Figure 8 (Indicated by arrows) The first opening 41 is located on the forward side of one of the blades 4, while the second opening 42 is located on the rearward side of the blade 4. This causes blood to flow from the first opening 41 to the second opening 42. The flushing channel 40 is in fluid communication with the central opening 32 to flush and cool the bearing 20. Figure 9 In the implementation method, with Figure 8 Similarly, in the implementation, the flushing channel 43 is configured to have a first opening 44 on the forward side of one of the blades 4. However, the flushing channel 43 extends through the blade 4 and exits at a second opening 45 located at the edge of the blade 4. This arrangement allows the use of centrifugal force to enhance the flushing flow from the first opening 44 to the second opening 45. Figure 10 Depicting and Figure 9 Another embodiment is similar to the previous one. However, the first opening 44' of the flushing channel 43' is arranged diagonally opposite to the blade 4, and the channel 43' extends through the blade 4 and exits at the second opening 45' of the blade 4. Therefore, in this embodiment, the flushing channel 43' extends diagonally or radially, rather than as in the previous one. Figure 9 In the embodiment, it extends tangentially so that it touches all sides of the bearing 20.

[0053] Figure 11 The text shows the relationship with... Figure 8 The implementation is similar to the previous one. The flushing channel 40' has a first opening 41' disposed on the forward side of one of the blades 4 relative to the axis of rotation, while a second opening 42' is disposed on the rearward side of the blade 4. (Note that although the flushing channel 40' is not...) Figure 11 Extending in the plane of the cross-section shown, but in relation to Figure 8 The cross-section shown extends in a plane that is very similar to the cross-section shown, but it still extends in a plane that is very similar to the cross-section shown. Figure 11 (As shown in the cross-sectional view.) The flushing channel 40' extends below the blade 4. However, in Figure 11 In this embodiment, although the flushing channel 40' does not extend in a plane perpendicular to the longitudinal axis 9, the second opening 42' is located downstream of the first opening 41'. Therefore, the second opening 42' is also arranged radially outward from the first opening 41'. The flushing flow can be enhanced by this arrangement through the centrifugal force in the exit section of the flushing channel 40' leading to the second opening 42'. Furthermore, the pressure difference between the first opening 41' and the second opening 42' in the passage 7 enhances the flushing flow.

[0054] It should be recognized that alternative combinations other than the aforementioned flushing channels 30, 30' can be provided. Figures 8 to 11 At least one of the flushing channels 40, 40', 43, 43' described. It should also be understood that the flushing channels 40, 40', 43, 43' are in fluid communication with the central opening 32 and the gap 31, thus allowing the same net flushing flow as described above.

[0055] Preferred Implementation

[0056] 1. Blood pump 1, comprising:

[0057] Pump housing 2, which has a blood inlet 5 and a blood outlet 6 connected by a passage 7.

[0058] Impeller 3 is arranged in the pump housing 2 to be rotatable about a rotation axis 9. Impeller 3 is provided with blades 4. The size and shape of the blades 4 are designed to transport blood along the passage 7 from the blood inlet 5 to the blood outlet 6. Impeller 3 is rotatably supported in the pump housing 2 by at least one contact bearing 20, the at least one contact bearing 20 including the bearing surface of the impeller 3 facing the pump housing 2.

[0059] At least one flushing channel 30 extends through the impeller 3 and is in fluid communication with the passage 7 via a first opening 34 and with the bearing 20 via a second opening 35. The flushing channel 30 is operatively associated with a secondary pump for pumping blood toward the bearing 20 through the flushing channel 30.

[0060] The secondary pump is formed at least in part by the at least one flushing passage 30 extending through the impeller 3 in a direction having at least one tangential portion.

[0061] 2. According to the blood pump in Section 1, the flushing channel 30 extends linearly through the impeller 3 and is offset relative to the axis of rotation 9.

[0062] 3. According to the blood pump in Section 2, wherein the flushing channel 30 extends in a plane parallel to the axis of rotation 9.

[0063] 4. According to the blood pump in Section 1, wherein the flushing channel 30 is curved and extends from the first opening 34 in the direction about the axis of rotation 9.

[0064] 5. The blood pump according to any one of Sections 1 to 4, wherein the flushing channel 30 extends from the first opening 34 at an angle relative to the surface of the impeller 3 in a circumferential direction opposite to the direction of rotation.

[0065] 6. The blood pump according to Section 5, wherein the angle is less than 20°, preferably less than 15°, and more preferably less than 10°.

[0066] 7. According to the blood pump in Section 5 or 6, wherein the flushing channel 30 extends from the first opening 34 in a direction substantially tangential to the surface of the impeller 3.

[0067] 8. The blood pump according to any one of Sections 1 to 7, wherein the distance between the second opening 35 and the axis of rotation 9 is less than or equal to the distance between the first opening 34 and the axis of rotation 9.

[0068] 9. The blood pump according to any one of Sections 1 to 8, wherein the distance between the rotation axis 9 and the first opening 34 is less than 50% of the distance between the rotation axis 9 and the point 36 where the flushing flow flows out to the passage 7, preferably less than 40%, more preferably less than 30%.

[0069] 10. A blood pump according to any one of Sections 1 to 9, wherein the impeller 3 includes a central opening 32 extending along the axis of rotation 9 and receiving a bearing 20, wherein a second opening 35 is in fluid communication with the central opening 32.

[0070] 11. The blood pump according to any of Sections 1 to 10, wherein the flushing channel 30 at the second opening 35 is guided substantially radially toward the axis of rotation 9.

[0071] 12. A blood pump according to any one of Sections 1 to 11, wherein the first opening 34 of the flushing channel 30 is arranged on the forward side of the blade 4 adjacent to one of the blades 4 of the impeller 3 with respect to the direction of rotation.

[0072] 13. A blood pump according to any of Sections 1 to 12, wherein the cross-section of the first opening 34 is circular.

[0073] 14. A blood pump according to any of Sections 1 to 12, wherein the cross-section of the first opening 34 is non-circular.

[0074] 15. A blood pump according to any one of Sections 1 to 13, wherein the first opening 34 is formed by an end of the flushing channel 30 that is at least partially exposed due to the inclination of the flushing channel 30 relative to the surface of the impeller 3.

[0075] 16. The blood pump according to any of Sections 1 to 15, wherein the protrusion 38 extends into the first opening 34 of the flushing channel 30, and the size and shape of the protrusion 38 are designed to increase the blood flow into the flushing channel 30 through the first opening 34.

[0076] 17. The blood pump according to any one of Sections 1 to 16, wherein the impeller 3 includes at least one wing 39 extending radially from the impeller 3 and disposed adjacent to and behind the first opening 34 of the flushing channel 30 relative to the direction of rotation.

[0077] 18. The blood pump according to Section 17, wherein the wing 39 extends over the first opening 34 of the flushing channel 30 and opens in the direction of rotation to allow blood to enter the first opening 34.

[0078] 19. A blood pump according to any one of Sections 1 to 16, wherein the impeller 3 includes a protrusion extending radially from the impeller 3, the protrusion forming a first opening 34 such that the cross section of the first opening 34 extends at an angle relative to the surface of the impeller 3 and opens in the direction of rotation, wherein, preferably, the angle is greater than 45°, more preferably, greater than 90°.

[0079] 20. The blood pump according to any of Sections 1 to 19 includes two or more flushing channels 30 arranged symmetrically with respect to the axis of rotation 9.

[0080] 21. A blood pump according to any one of Sections 1 to 20, wherein the secondary pump includes grooves or blades formed in the surface of the impeller 3.

[0081] 22. A blood pump according to any one of Sections 1 to 21, wherein the impeller 3 has a portion 33 extending radially outward in a downstream direction, and a first opening 34 of the flushing channel 30 is disposed in said portion 33.

[0082] 23. The blood pump according to Section 22, wherein the portion 33 tapers radially outward in a conical shape along the downstream direction.

[0083] 24. The blood pump according to section 22 or 23, wherein the blades 4 of the impeller 3 extend over said portion 33.

[0084] 25. A blood pump according to any one of sections 22 to 24, wherein part 33 is integrally formed with or separately from impeller 3.

[0085] 26. The blood pump according to any one of Sections 1 to 25, wherein the first opening 34 of the flushing channel 30 is located in the downstream half of the impeller 3.

[0086] 27. A blood pump according to any of Sections 1 to 26, wherein a first opening 34 of the flushing channel 30 is provided in a region of the impeller 3 under higher pressure than the region in the impeller 3 where the bearing 20 is located during operation of the blood pump 1, so as to cause blood flow from the first opening 34 through the flushing channel 30 to the bearing 20.

[0087] 28. A blood pump according to any of Sections 1 to 27, wherein the blood flow from the first opening 34 through the flushing channel 30 is in the direction toward the blood outlet 6 of the pump housing 2.

[0088] 29. A blood pump according to any one of Sections 1 to 28, wherein a first opening 41 is provided on the forward side of the blade 4, a second opening 42 is provided on the rearward side of the blade 4, and a flushing channel 40 extends below the blade.

[0089] 30. A blood pump according to any one of Sections 1 to 29, wherein a flushing channel 43 extends within a blade 4, wherein a first opening 44 is provided on the forward side of the blade 4, and a second opening 45 is provided in the blade 4, preferably on the radial outer edge of the blade 4.

[0090] 31. A blood pump according to any of Sections 1 through 30, wherein the contact bearing 20 is a pivot bearing.

[0091] 32. A blood pump according to any one of Sections 1 to 31, wherein blood pump 1 is an axial blood pump, a centrifugal blood pump, or a hybrid blood pump.

Claims

1. A blood pump (1), comprising: Pump housing (2), the pump housing (2) having a blood inlet (5) and a blood outlet (6) connected by a passage (7); An impeller (3) is arranged in the pump housing (2) to be rotatable about a rotation axis (9). The impeller (3) is provided with blades (4) which are sized and shaped to transport blood along the passage (7) from the blood inlet (5) to the blood outlet (6). The impeller (3) is rotatably supported in the pump housing (2) by at least one contact bearing (20), which includes a bearing surface of the impeller (3) facing the pump housing (2). At least one flushing channel (43') extends through the impeller (3) and is in fluid communication with the passage (7) via a first opening (44') and with the bearing (20) via a second opening, wherein the flushing channel (43') extends through one of the blades (4) and the first opening (44') is configured to be diagonally opposite to the blades (4).

2. The blood pump according to claim 1, wherein The flushing channel (43') extends diagonally or radially through the impeller.

3. The blood pump according to claim 1 or 2, wherein The flushing channel (43') is operably associated with a secondary pump for pumping blood through the flushing channel (43') toward the bearing (20), wherein, The secondary pump is formed at least in part by the at least one flushing channel (43').

4. The blood pump according to claim 1 or 2, wherein The flushing channel (43') exits at the outflow opening (45') located at the radial outer edge of the blade (4), and the first opening (44') is configured to be diagonally opposite to the outflow opening (45').

5. The blood pump according to claim 1 or 2, wherein The distance between the rotation axis (9) and the first opening (44') is less than 50% of the distance between the rotation axis (9) and the point (36) where the flushing flow exits into the passage (7).

6. The blood pump according to claim 1 or 2, wherein The impeller (3) includes a central opening (32) extending along the axis of rotation (9) and accommodating the bearing (20), wherein, The second opening is in fluid communication with the central opening (32).

7. The blood pump according to claim 6, wherein The flushing channel (43') at the second opening is guided substantially radially toward the axis of rotation (9).

8. The blood pump according to claim 1 or 2, wherein The cross-section of the first opening (44') is circular or non-circular.

9. The blood pump according to claim 1 or 2, wherein The first opening (44') is formed by the end of the flushing channel (43') that is at least partially exposed due to the inclination of the flushing channel (43') relative to the surface of the impeller (3).

10. The blood pump according to claim 1 or 2, wherein The protrusion (38) extends into the first opening (44') of the flushing channel (43'), and the size and shape of the protrusion (38) are designed to increase blood flow into the flushing channel (43') through the first opening (44').

11. The blood pump according to claim 1 or 2, wherein The impeller (3) includes at least one wing (39) that extends radially from the impeller (3) and is positioned adjacent to and behind the first opening (44') of the flushing channel (43') relative to the direction of rotation.

12. The blood pump according to claim 11, wherein The wing (39) extends over the first opening (44') of the flushing channel (43') and opens in the direction of rotation to allow blood to enter the first opening (44').

13. The blood pump according to claim 1 or 2, comprising: Two or more flushing channels (43') are arranged symmetrically with respect to the axis of rotation (9).

14. The blood pump according to claim 1 or 2, wherein The impeller (3) has a portion (33) that extends radially outward in the downstream direction, and the first opening (44') of the flushing channel (43') is disposed in the portion (33).

15. The blood pump according to claim 1 or 2, wherein The first opening (44') of the flushing channel (43') is located in the downstream half of the impeller (3).

16. The blood pump according to claim 1 or 2, wherein The first opening (44') of the flushing channel (43') is located in a region of higher pressure in the impeller (3) during operation of the blood pump (1) compared to the region in the impeller (3) where the bearing (20) is located, so as to cause blood flow from the first opening (44') through the flushing channel (43') to the bearing (20).

17. The blood pump according to claim 1 or 2, wherein The blood flow from the first opening (44') through the flushing channel (43') is in the direction toward the blood outlet (6) of the pump housing (2).

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