Blood pump

Abstract

The present disclosure relates to a blood pump according to claim 1, comprising: - a pump housing having a cylindrical plunger chamber; - an axially and rotatably sliding free-floating plunger located in the center of the cylindrical plunger chamber, thereby dividing the cylindrical plunger chamber into a left chamber and a right chamber, wherein the left chamber and the right chamber each comprise an inlet and an outlet arranged transversely to and in communication with the left and right chambers; - a linear motor unit configured to alternately generate an electromagnetically driven translational motion of the plunger along a longitudinal axis of the plunger chamber between a first end position and a second end position; and - at least one rotary motor unit configured to generate an electromagnetically driven rotational motion of the plunger around the longitudinal axis during the translational motion of the plunger between the first end position and the second end position.

Description

TECHNICAL FIELD

[0001] The present invention relates to a blood pump. BACKGROUND

[0002] Cardiovascular diseases account for one third of all causes of death and are the most common cause of death worldwide. One of the most common cardiovascular diseases is heart failure, which affects at least 26 million people. In cases of severe heart failure, where drug therapy is ineffective, heart transplantation is the treatment of choice. However, donor organs are rare. Therefore, mechanical blood pumps such as ventricular assist devices (VAD) or total artificial hearts (TAH) have been developed to shorten the time available for donor hearts or to completely replace the heart. With the rise of small implantable rotary blood pumps (RBP) for use as ventricular assist devices, large pulsatile pumps have lost importance in the treatment of end-stage heart failure. The available pulsatile systems are based on valve-bearing positive displacement pumps and require large pneumatic drive units, which greatly limit the quality of life.

[0003] Despite the therapeutic efficacy of RBP, patients still experience several adverse events related to the impaired blood compatibility of these devices, leading to von Willebrand factor deficiency, platelet activation, hemolysis, and to severe bleeding, stroke, and pump thrombosis. Despite the lower shear rates in modern clinical pulsatile devices, thrombosis is prone to occur in the valve area due to long residence times and disturbed flow patterns around the valve disc or leaflets.

[0004] Existing mechanical circulatory support (MCS) devices can ensure that most recipients survive and improve their quality of life, however, current RBP are associated with severe adverse events (thromboembolic and bleeding complications) due to poor blood compatibility. Pulsatile devices have the potential to reduce damage to blood cells. However, the risk of thrombosis due to the interaction between blood and artificial materials that make up the device remains.

[0005] Recent observations emphasize the medical need for blood-compatible blood pumps for use as ventricular assist devices and total artificial hearts: severe complications affect the long-term performance of all implantable rotary blood pumps. Non-physiological blood flow patterns and the interaction between the pump and the cardiovascular system trigger severe adverse events. Only 20% of patients do not experience severe adverse events, including right heart failure, bleeding, or stroke, after 24 months. Therefore, the quality of life is severely impaired and new developments are urgently needed. For adult patients with biventricular failure and for children with congenital heart disease, such as Fontan patients, a small implantable blood-compatible TAH with a low risk of complications is an urgently needed treatment.

[0006] It is therefore an object of the present invention to overcome or reduce at least some of the disadvantages of the prior art and to form a new pumping concept for delivering a pulsatile flow to the cardiovascular system. SUMMARY

[0007] Embodiments of the present disclosure seek to address at least one problem existing in the prior art, at least to some extent. In particular, the present disclosure relates to a blood pump comprising:

[0008] - a pump housing having a cylindrical plunger chamber;

[0009] - a freely floating plunger axially and rotatably sliding in the center of the cylindrical plunger chamber, thereby dividing the cylindrical plunger chamber into a left chamber and a right chamber, wherein the left and right chambers each comprise an inlet and an outlet arranged transversely to and in communication with the left and right chambers;

[0010] - a linear motor unit configured to produce an electromagnetically driven translational movement of the plunger along a longitudinal axis of the plunger chamber alternatingly between a first end position and a second end position; and

[0011] - at least one rotary motor unit configured to produce an electromagnetically driven rotational movement of the plunger around the longitudinal axis during the translational movement of the plunger between the first end position and the second end position.

[0012] Further aspects of the present disclosure can be gleaned from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0013] Exemplary embodiments will become more fully understood from the detailed description and accompanying drawings, wherein:

[0014] Figure 1A Fig. 1 B shows a cross-sectional view of an exemplary embodiment of a blood pump.

[0015] Figure 2A Fig. 2B shows an electromagnetic drive system of a blood pump according to an exemplary embodiment.

[0016] Figure 3A Fig. 3B shows a cross-sectional view of a plunger chamber and a plunger according to an exemplary embodiment.

[0017] Figure 4 A process showing the outlet flow and pressure of one of the chambers over a period of time.

[0018] Figure 5 A centrifugal ratio impact on the theoretical load capacity of a blood pump is shown.

[0019] Figures 6A-6D Another exemplary embodiment of a blood pump is shown. DETAILED DESCRIPTION

[0020] The features and method of implementation of the present inventive concept can be more readily understood by reference to the following detailed description of embodiments and the accompanying drawings. However, the present invention can be embodied in various different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the aspects and features of the present invention to those skilled in the art, and will enable one of ordinary skill in the art to make and use the present invention, without having to resort to unnecessary technical details. In the drawings and specification, like numerals refer to like elements, and so descriptions thereof will not be repeated unless otherwise noted. In the drawings, the relative sizes of elements, layers, and regions can be exaggerated for clarity.

[0021] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0022] General Concepts

[0023] The present disclosure generally relates to a blood pump comprising:

[0024] - a pump housing having a cylindrical plunger chamber;

[0025] - a freely floating plunger axially and rotatably slidable in the center of the cylindrical plunger chamber, thereby dividing the cylindrical plunger chamber into a left chamber and a right chamber, wherein the left chamber and the right chamber each comprise an inlet and an outlet arranged transversely to and in communication with the left and right chambers;

[0026] - a linear motor unit configured to alternately generate an electromagnetically driven translational movement of the plunger along a longitudinal axis of the plunger chamber between a first end position and a second end position; and

[0027] - at least one rotary motor unit configured to generate an electromagnetically driven rotational movement of the plunger around the longitudinal axis during the translational movement of the plunger between the first end position and the second end position.

[0028] The new pumping concept delivers pulsatile flow to the cardiovascular system by a single moving component, without valves at risk and with superior blood compatibility. The design is in theory dimensioned for implantation in pediatric and adult patients.

[0029] According to the present disclosure, the blood pump comprises a first motor unit configured to generate a translation movement of the movable plunger driven electromagnetically and at least one further second motor unit configured to generate a rotational movement of the movable plunger driven electromagnetically around the longitudinal axis of the cylindrical plunger chamber. The linear movement and the rotational movement have to be performed together as long as it leads to both mentioned end positions of the plunger. In other words, the rotational movement or movement can be uniform or performed at different speeds over time during the translation movement or movement of the plunger from one end position to the other end position. Preferably, the rotational movement can be a continuous rotational movement. The same applies to the translation movement.

[0030] By superimposition of both movement sequences, the present blood pump combines the advantages of the pulsatile and the rotary blood pumps of the prior art. In particular, the size of the blood pump can be comparable to other TAHs developed on the basis of the rotary principle. The single movement component, i.e. the plunger, increases the reliability of the pulsatile valveless pump to the level of the rotary blood pump. Due to the valveless design, the blood pump can be superior to the common pulsatile devices in terms of reliability and thrombogenic risk. At the same time, the pulsatile pumping principle with much lower velocities and shear rates than RBP can reduce adverse events associated with the working principle of modern RBP. The size of the pump for adults can be approximately 10 x 5 cm, which is much smaller than comparable systems. Furthermore, the design can be scaled down for use in pediatric patients.

[0031] According to one embodiment, the linear motor unit is interpreted as a multiphase, e.g. 2-phase or 3-phase, linear induction motor (LIM) comprising an axially polarized annular array of permanent magnets positioned within the plunger and a first segmented winding wired around the cylindrical plunger chamber. Typically, the primary coil of a linear motor is usually composed of a flat magnetic core with transverse slots, which are usually cut straight, the coils are placed in the slots, each phase has alternating polarity, so that the different phases physically overlap. The second layer is usually an aluminum sheet, usually with an iron backplate. Some LIMs are double-sided, with one primary coil on each secondary side, in which case an iron backer is not required. However, according to the present embodiment, the electromagnet is adapted to function as a stator (i.e. representing the primary coil), while the secondary coil comprises permanent magnets positioned in the movable plunger. Thus, the electric motor is a brushless motor, which can avoid any wear and spark formation.

[0032] In addition to or instead of using the previously mentioned polyphase linear induction motor, the rotary motor unit can be interpreted as a polyphase (e.g. 2-phase or 3-phase) rotary induction motor comprising a radially polarized permanent magnet array positioned within the plunger and a second segmented winding wound along the axial sides and around the cylindrical plunger chamber. The second segmented winding can comprise a soft magnetic back yoke and a polyphase (e.g. 2-phase or 3-phase) wire coil wound along the axial sides and the circumference of the cylindrical plunger chamber. The radially polarized permanent magnet array can be positioned close to each base face of the plunger facing the left and right chambers. Thus, the stator of the rotary motor unit is represented by the wound coil arrangement, the moving part comprising the permanent magnets. Again, this arrangement allows for a brushless implementation of the rotary motor unit.

[0033] According to another embodiment, the inlet and outlet of the left chamber are located on opposite sides of the cylindrical plunger chamber, and the inlet and outlet of the right chamber are located on opposite sides of the cylindrical plunger chamber, respectively.

[0034] Furthermore, the plunger length can be in the range of 60 to 100 mm, and the plunger radius can be in the range of 40 to 60 mm. Separately or in addition thereto, the volume of the left or right chamber can be in the range of 5 to 50 ml.

[0035] Another embodiment provides that the motion frequency of the translational motion of the plunger is in the range of 2 to 10 Hz. This ensures that sufficient fluid dynamics are generated to support the plunger within the cylindrical housing.

[0036] The plunger can further be interpreted such that in the first end position, the side surface of the plunger closes the inlet of the left chamber and the outlet of the right chamber, whereas the outlet of the left chamber and the inlet of the right chamber are open, and whereby the closing state of the inlets and outlets is completely reversed in the second end position. In other words, the inlet and outlet of each chamber are alternately closed and open, i.e. if the inlet of a certain chamber is open, its outlet will be closed. Furthermore, if the inlet of one of the chambers is open, the inlet of the other chamber is closed.

[0037] In particular, the plunger has a left base face facing the left chamber and a right base face facing the right chamber. According to one embodiment, a curved portion of the left base face is bent inwardly such that (i) in the first end position of the plunger, the outlet of the left chamber is open, whereas the inlet of the left chamber is closed, and (ii) in the second end position of the plunger, the inlet of the left chamber is open, whereas the outlet of the left chamber is closed. Furthermore, a portion of the right base face is bent inwardly such that (i) in the first end position of the plunger, the inlet of the right chamber is open, whereas the outlet of the right chamber is closed, and (ii) in the second end position of the plunger, the outlet of the right chamber is open, whereas the inlet of the left chamber is closed. In other words, the base faces of the left and right side of the plunger do not extend perpendicular to the longitudinal axis of the plunger. Said base faces are also not planar, but have a surface profile comprising a curved region inwardly, i.e. towards the plunger. This allows to avoid pressure peaks during pumping.

[0038] The surface profile of the left base face and the surface profile of the right base face can be point-symmetric to each other. In this way, the manufacturing process can be simplified.

[0039] According to another embodiment, a flow divider is connected between at least one of the left chamber and the right chamber or the inlets of the left chamber and the right chamber. The flow divider is configured to allow a pressure equilibrium between the two chambers. For example, the flow divider can be realized by a groove within the pump housing, which extends between the two chambers and ends in the left inlet and the right inlet, respectively.

[0040] Alternatively or additionally, the rotational movement of the plunger around the longitudinal axis is a non-synchronous or non-uniform rotational movement during the translational movement of the plunger chamber between the first end position and the second end position. In other words, at least one of these two movements represents a discontinuous behavior. Thus, an exact balancing of the outputs of the left chamber and the right chamber is possible. In other words, by adjusting the rotational speed, the pump efficiency of each chamber and thus the amount of blood expelled can be adjusted. The measures can prevent, for example, lung congestion or so-called suction events.

[0041] According to another embodiment of the present disclosure, a fluid dynamic bearing can be provided between the outer surface of the plunger and the inner surface of the plunger chamber of the pump housing. The bearing can ensure a smooth plunger movement without the risk of dry friction and material wear. In particular, the gap of the fluid dynamic bearing can be less than 100 pm. In this case, only a small amount of blood components can enter this small fluid dynamic bearing, resulting in low blood trauma in these areas.

[0042] Exemplary Embodiments

[0043] Figure 1A and 1B A cross-sectional view of an exemplary embodiment of a blood pump 100 is shown. The blood pump 100 comprises a pump housing 10 having a cylindrical plunger chamber 12. An axially and rotatably sliding free-floating plunger 20 is located in the center of the cylindrical plunger chamber 12, thereby dividing the cylindrical plunger chamber 12 into a left chamber 30 and a right chamber 40. The left chamber 30 comprises an inlet 32 and an outlet 34, and the right chamber 40 comprises an inlet 42 and an outlet 44, the inlet 32 and the outlet 34 of the left chamber 30 being arranged transversely to and in communication with the left chamber 30, and the inlet 42 and the outlet 44 of the right chamber 40 being arranged transversely to and in communication with the right chamber 40.

[0044] The linear motor unit 50 is configured to move the plunger 20 in the direction of the longitudinal axis L between Figure 1A a first end position and Figure 1BThe illustrated alternating translation (or translational) movement of the plunger 20 along the longitudinal axis of the plunger chamber 12 is caused by electromagnetic drive. Here, the linear motor unit 50 is explained as a three-phase linear induction motor comprising an axially polarized annular permanent magnet array 52 positioned within the plunger 20 and a first segmented winding 54 wired around the cylindrical plunger chamber 12.

[0045] The rotary motor unit is configured to cause an electromagnetically driven partial rotational movement of the plunger 20 around the longitudinal axis during the translational movement between the first end position and the second end position within the plunger 20. For the sake of clarity, Figure 1A and 1B The rotary motor unit is not illustrated in detail, but will be described in detail below. For the sake of understanding Figure 1A and 1B of the pumping mechanism in

[0046] The two inlets 32, 42 of the pump 100 are connected to the left atrium and the right atrium, respectively. The outlets 34, 44 are in line with the pulmonary artery and the aorta. The plunger 20 is electromagnetically driven within the cylindrical plunger chamber 12 with a reciprocating translational and uniform rotational movement. Thereby, the plunger 20 divides the pump housing 10 into a left chamber 30 and a right chamber 40, each having one inlet 32, 42 and one outlet 34, 44. From Figure 1A the illustrated first end position to Figure 1B the illustrated second end position, the translational movement causes the filling of one chamber, here the right chamber 40, while the other chamber, here the left chamber 30, is simultaneously emptied. By rotation, the openings of the inlets 32, 42 and outlets 34, 44 of both chambers 30, 40 are controlled, so that mechanical check valves are eliminated. By this combination of rotation and translation, the entire pumping function of the left and right heart is accomplished by only one moving part.

[0047] In Figure 1A and 1B , the pumping and actuation principle is indicated by arrows. The filling of the right chamber 40 is accompanied by the simultaneous emptying of the left chamber 30. The translational movement is achieved by the wired coils of the first segmented winding 54, thereby generating a Lorentz force FL on the plunger 20. The translational movement is superimposed with a rotational 180° movement of the plunger 20. The inlet 42 of the right chamber 40 and the outlet 34 of the left chamber 30 are closed at the second end position of the plunger 20, without the need for valves. When the current in the wired coils is reversed, the plunger 20 is forced to move back to the first end position, emptying the right chamber 40, while filling the left chamber 30. The dashed lines indicate the magnetic flux path of the axially polarized annular permanent magnet array 52.

[0048] The frequency of motion of the plunger 20 can be in the range of 3 to 5 Hz to support a patient in a resting state, resulting in a relatively low speed compared to state-of-the-art rotary blood pumps and potentially leading to a significantly lower blood trauma. Due to the edge stagnation areas and the low priming volume within the pump 100, a high washout potential is expected. The simple geometry allows the use of ultra-high precision, resulting in a smooth blood contact surface and thus a reduced risk of thrombus formation.

[0049] Due to the simple rotational symmetry of the outer surface of the plunger 20 and the inner surface of the plunger chamber 12 of the pump housing 10, an ultra-high precision can be manufactured. A fluid dynamic bearing can be provided between the outer surface of the plunger 20 and the inner surface of the plunger chamber 12 of the pump housing 10 (not shown). The gap of the fluid dynamic bearing can be less than 100 pm. The bearing can ensure a smooth plunger motion without the risk of dry friction and material wear. Recent findings suggest that only a small amount of blood components can enter such a small fluid dynamic bearing, resulting in a low blood trauma of these areas.

[0050] Compared to other pulsatile blood pumps, the electromagnetic motor consisting of the linear motor unit 50 and at least one rotary motor unit drives the plunger 20 in an efficient way: for translational motion, two wire coils around the middle of the pump 100 housing are energized with opposite current directions to generate an optimal force. Rotational motion will be achieved by one or two radial flux motors.

[0051] Figure 2A The drive system is described in more detail in / 2B. In addition to the centrally located linear motor unit 50, two rotary motor units 60, 61 are arranged on its left and right side. Each rotary motor unit 60, 61 is interpreted as a multi-phase rotary induction motor, comprising an array of radially polarized permanent magnets 62, 63 located within the plunger 20 and a second segmented winding 64, 65 comprising a soft magnetic back yoke and a multi-phase wire coil wound along the axial sides and the circumference of the cylindrical plunger chamber 12. Here, the rotary motor units 60, 61 are implemented as 2-phase single-pole permanent magnet type stepper motors. The magnetic flux path of the rotary motor unit 60 is shown as a dashed line in Figure 2B , resulting in a torque that causes the plunger 20 to rotate.

[0052] Figure 3A and 3B are cross-sectional views of the plunger chamber 12 and the plunger 20 according to exemplary embodiments. The diameters of the two inlets 32, 42 can be in the range of 5 to 25 mm and are connected to the left and right atrium, respectively, for example, by means of a conical textile material. The outlets 34, 44 can have similar diameters of 5 to 25 mm and can be connected to a graft material and anastomosed to the pulmonary artery and the aorta. As mentioned above, the plunger 20 is electromagnetically driven within the cylindrical plunger chamber 12 with a reciprocating translational and uniform rotational motion. AsFigure 3A The translational movement from the left chamber 30 to the right chamber 40 pumps blood and injects it into the aorta through the outlet 34. At the same time, the right chamber 40 is filled through the inlet 42. The left inlet 32 and the right outlet 44 are closed by the plunger 20. As Figure 3B The rotation of the plunger 20 opens the inlet 32 of the left chamber 30 and closes the inlet 42 of the right chamber 40. The translational movement from right to left empties the right chamber 40 and fills the left chamber 30. By way of example only: for a pump for an adult human, the total length LI can be 100 mm, the length L2 of the plunger 20 can be 83 mm, and the diameter D of the plunger chamber 12 can be 50 mm.

[0053] Furthermore, the plunger 20 has a left base surface 22 facing the left chamber 30 and a right base surface 23 facing the right chamber 40. The curved portion 24 (or notch) of the left base surface 22 is curved inwardly such that (i) in the first end position of the plunger 20, the inlet 32 of the left chamber 30 is open, whereas the outlet 34 of the left chamber 30 is closed; and (ii) in the second end position of the plunger 20, the outlet 34 of the left chamber 30 is open, whereas the inlet 32 of the left chamber 30 is closed. Figure 3A The curved portion 24 (or notch) of the left base surface 22 is curved inwardly such that (i) in the first end position of the plunger 20, the inlet 32 of the left chamber 30 is open, whereas the outlet 34 of the left chamber 30 is closed; and (ii) in the second end position of the plunger 20, the outlet 34 of the left chamber 30 is open, whereas the inlet 32 of the left chamber 30 is closed. Figure 3B The curved portion 24 (or notch) of the left base surface 22 is curved inwardly such that (i) in the first end position of the plunger 20, the inlet 32 of the left chamber 30 is open, whereas the outlet 34 of the left chamber 30 is closed; and (ii) in the second end position of the plunger 20, the outlet 34 of the left chamber 30 is open, whereas the inlet 32 of the left chamber 30 is closed. In other words, the base surfaces 22, 23 on the left and right sides of the plunger 20 do not extend perpendicular to the longitudinal axis of the plunger 20. Said base surfaces 22, 23 are also not planar, but have a surface profile comprising a curved region inwardly (i.e. towards the plunger 20). This allows to avoid pressure peaks during pumping, thereby improving blood compatibility.

[0054] According to an exemplary embodiment, the frequency of movement of the plunger 20 can be in the range of 2 to 10 Hz. Figure 4 The process of flow and pressure generation in the left chamber 30 is shown. The simple geometry of the blood plunger 20 and the plunger chamber 12 allows to use ultra-high precision, thereby making the blood contact surfaces smooth, thereby reducing the risk of thrombus formation. Each stroke pumps the chambers 30, 40 and fills them with a volume of 5 to 50 ml.

[0055] By way of example only, the height H of the curved portions 24, 25 can be 20 mm, and the depth D of the curved portions 25, 24 can be 28 mm. From Figure 3A and 3B It can further be seen from Figs. 2 and 3 that the surface profile of the left base surface 22 and the surface profile of the right base surface 23 are point-symmetric to each other. In this way, the manufacturing process can be simplified, and the pump volumes of the two chambers 30, 40 are substantially equal. This way, it is also ensured that optimal operation is performed with minimal risk of blood trauma.

[0056] The outer surface of the plunger 20 (or plunger shell region) and the inner surface of the plunger chamber 12 of the pump housing (or inner shell region) can be manufactured with ultra-high precision due to its simple rotational symmetry. Thus, fluid dynamic bearings with a gap clearance in the range of 0 to 500 pm can be realized. Said bearings withstand forces > 20 N, ensuring smooth motion of the plunger with a maximum eccentricity < 95%, without the risk of dry friction and material wear. Figure 5 An example of the load capacity of such a bearing at a gap clearance of 75 pm is given, showing the theoretical load capacity of the blood pump in relation to the centrifugal rate at a rotational frequency of 3 Hz.

[0057] The shuttle motion in combination with the pressure difference between the left chamber 30 and the right chamber 40 can lead to additional bearing stability due to the Lomakin effect. A certain gap clearance is required to allow sufficient gap flow to cool the bearing regions (heat generated by the motor coils) and to meet the requirement of a maximum local temperature rise of 2 K. Furthermore, due to the small gap, only a small amount of blood components can enter the fluid dynamic bearing gap, resulting in a lower blood trauma of these regions.

[0058] Figures 6A to 6D Another exemplary embodiment of a blood pump 100 is shown. An electromagnetic motor system drives a simultaneous translational and rotational plunger motion. In the embodiment shown in the drawing, the translational motion is realized by a linear motor unit 50. The linear motor unit 50 comprises an axially polarized annular permanent magnet array 52 generating a magnetic field, which is composed of permanent magnets and a soft magnetic material ring 55. The axially polarized annular permanent magnet array 52 is located within the plunger 20. Furthermore, a first segmented winding 56 is wired around the cylindrical plunger chamber 12 and comprises a back yoke 57 and segmented copper coils 58. During operation, the soft magnetic material ring 55 guides the magnetic flux through the segmented copper coils 58 wired around the middle section of the plunger chamber 12. The position-dependent excitation of the segmented copper coils 58 generates a Lorentz force in axial direction.

[0059] For the rotational motion, permanent magnets 67 close to the curved sections 24, 25 of the plunger 20 are radially polarized and connected by a soft magnetic material hollow shaft 66 to form a lightweight radially polarized permanent magnet array 62, 63. A soft magnetic back yoke 68 closes the magnetic flux path of the permanent magnets 67 and guides it through wired coils 70, 71, 72. The 3-phase wired coils 70, 71, 72 are wound along the axial sides and around the entire plunger chamber 12. In this way, a 3-phase slotless permanent magnet motor is realized.

[0060] Reference signs

[0061] 10 pump housing

[0062] 12 plunger chamber

[0063] 20 plunger

[0064] 22 left base surface

[0065] 23 right base surface

[0066] 24 curved portion of left base surface 22

[0067] 25 curved portion of right base surface 23

[0068] 30 left chamber

[0069] 32 inlet of left chamber 30

[0070] 34 outlet of left chamber 30

[0071] 40 right chamber

[0072] 42 inlet of right chamber 40

[0073] 44 outlet of right chamber 40

[0074] 50 linear motor unit

[0075] 52 axially polarized annular permanent magnet array

[0076] 54 first segmented winding

[0077] 60, 61 rotary motor unit

[0078] 62, 63 radially polarized permanent magnet array

[0079] 64, 65 second segmented winding

[0080] 66 soft magnetic material hollow shaft

[0081] 67 permanent magnet

[0082] 68 soft magnetic back yoke

[0083] 70, 71, 72 wire coil

[0084] 100 blood pump

Claims

1. A blood pump (100) comprising: - a pump housing (10) having a cylindrical plunger chamber (12); - an axially and rotatably sliding free-floating plunger (20) located in the center of the cylindrical plunger chamber (12) dividing the cylindrical plunger chamber (12) into a left chamber (30) and a right chamber (40), wherein the left chamber (30) comprises an inlet (32) and an outlet (34), the right chamber (40) comprises an inlet (42) and an outlet (44), the inlet (32) and the outlet (34) of the left chamber (30) are arranged transversely to and in communication with the left chamber (30), the inlet (42) and the outlet (44) of the right chamber (40) are arranged transversely to and in communication with the right chamber (40); - a linear motor unit (50) configured to generate an electromagnetically driven translational motion of the plunger (20) along a longitudinal axis of the plunger chamber (12) alternatingly between a first end position and a second end position; and - at least one rotary motor unit (60, 61) configured to generate an electromagnetically driven rotational motion of the plunger (20) around the longitudinal axis during the translational motion of the plunger (20) between the first end position and the second end position; wherein the plunger (20) is configured such that in the first end position a lateral surface of the plunger (20) closes the inlet (32) of the left chamber (30) and the outlet (44) of the right chamber (40), while the outlet (34) of the left chamber (30) and the inlet (42) of the right chamber (40) are open, and the closing state of the inlet (32) and the outlet (34) of the left chamber (30) and the inlet (42) and the outlet (44) of the right chamber (40) is fully reversed in the second end position; wherein the plunger (20) has a left base surface (22) facing the left chamber (30) and a right base surface (23) facing the right chamber (40); a curved portion (24) of the left base surface (22) is curved inwardly such that in the first end position of the plunger (20) the outlet (34) of the left chamber (30) is open; and a curved portion (25) of the right base surface (23) is curved inwardly such that in the first end position of the plunger (20) the inlet (42) of the right chamber (40) is open.

2. The blood pump according to claim 1, wherein the linear motor unit (50) is interpreted as a multiphase linear induction motor comprising an axially polarized annular permanent magnet array (52) positioned within the plunger (20) and a first segmented winding (56) wired around the cylindrical plunger chamber (12).

3. The blood pump according to claim 1 or 2, wherein the rotary motor unit (60, 61) is interpreted as a multiphase rotary induction motor comprising a radially polarized permanent magnet array (62, 63) located within the plunger (20) and a second segmented winding (64, 65) wound along the axial sides and the circumference of the cylindrical plunger chamber (12). ​ 4. The blood pump of claim 3, wherein the array of radially polarized permanent magnets (62, 63) is positioned close to each base face (22, 23) of the plunger (20) facing the left chamber (30) and the right chamber (40).

5. The blood pump of any one of claims 1-2 and 4, wherein the inlet (32) and the outlet (34) of the left chamber (30) are located on opposite sides of the cylindrical plunger chamber (12), and the inlet (42) and the outlet (44) of the right chamber (40) are located on opposite sides of the cylindrical plunger chamber (12), respectively.

6. The blood pump of any one of claims 1-2 and 4, wherein the plunger length is in the range of 60 to 100 mm, and the plunger radius is in the range of 40 to 60 mm.

7. The blood pump of any one of claims 1-2 and 4, wherein the volume of the left or right chamber (30, 40) is in the range of 5 to 50 ml.

8. The blood pump of any one of claims 1-2 and 4, wherein the motion frequency of the translational motion of the plunger (20) is in the range of 2 to 10 Hz.

9. The blood pump of any one of claims 1-2 and 4, wherein the surface profile of the left base face (22) and the surface profile of the right base face (23) are point-symmetric to each other.

10. The blood pump of any one of claims 1-2 and 4, wherein a shunt is connected between at least one of the left chamber (30) and the right chamber (40) or the inlets (32, 42) of the left chamber (30) and the right chamber (40), the shunt being configured to allow pressure between the left chamber (30) and the right chamber (40) to reach equilibrium.

11. The blood pump of any one of claims 1-2 and 4, wherein during the translational motion of the plunger (20) between the first end position and the second end position, the partial rotational motion of the plunger around the longitudinal axis is a non-synchronous or non-uniform rotational motion.

12. The blood pump of any one of claims 1-2 and 4, wherein a hydrodynamic bearing is provided between the outer surface of the plunger (20) and the inner surface of the plunger chamber (12) of the pump housing (10).

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