Magnetic levitation centrifugal pump

Abstract

A magnetic levitation centrifugal pump, comprising a volute casing (200), a static magnetic ring (22) and a rotor (100). The volute casing (200) has a levitation cavity, a medium inlet and a medium outlet. The rotor (100) is located inside the levitation cavity. The static magnetic ring (22) is fixed to the volute casing. The rotor (100) includes a rotor body, a movable magnetic ring (16) positioned on the rotor body, and at least two blades (13). The movable magnetic ring (16) is coaxially and concentrically arranged in the static magnetic ring (22) so as to limit the radial position between the rotor body and the volute casing (200). A magnetic steel assembly (14) is fixed to the rotor body, and a magnetic member (17) is further fixed to the rotor body. A drive coil assembly (21) provided opposite to the magnetic steel assembly (14) is encapsulated in the volute casing (200). The drive coil assembly (21) cooperates with the magnetic steel assembly (14) to rotate the rotor body in the circumferential direction. A magnetic levitation coil assembly (27) is fixed to the volute casing (200). When the magnetic levitation coil assembly (27) is energized, an axial force is generated by the magnetic member (17) and the magnetic levitation coil assembly (27). Due to the magnetic force action between the movable magnetic ring (16) and the static magnetic ring (22), the complete levitation operation of the rotor (100) can be realized, reducing heat generation and wear, minimizing the possibility of thrombus generation and the possibility of blood cells being crushed and destroyed. The rotational drive and axial position control of the rotor (100) are completely independent, and the control logic is simple.

Description

Technical Field

[0001] Cross - reference to related applications This application claims the priority of a Chinese patent application with application number 202210565543.2 and application title "Magnetic Levitation Centrifugal Pump", which was filed with the Chinese Patent Office on May 23, 2022, and all of its contents are incorporated herein by reference.

[0002] This application relates to the field of vibration reduction technology, and particularly to magnetic levitation centrifugal pumps.

Background Art

[0003] Heart failure (English: Heart failure, abbreviated as "heart failure" in Chinese) simply means that the natural heart cannot pump sufficient blood flow to maintain the body's blood circulation. According to the statistics of the World Health Organization (WHO), about 15% to 20% of people suffer from various degrees of heart failure. The number of people over 65 years old hospitalized due to heart failure accounts for more than 50% of the total number of hospitalizations, and the mortality rate after 5 years exceeds 50%. For heart failure patients, there are only three treatment options: conservative drug treatment, heart transplantation, and ventricular assistance. Drug treatment has poor effects, and heart transplantation is very difficult due to donor limitations. Therefore, the ventricular assist device (English full name: Ventricular Assist Device, VAD) has become the most effective treatment option for various types of end - stage heart failure generally recognized worldwide. The main component of the ventricular assist device is the blood pump (English full name: Blood Pump). Generally, the inflow pipeline of the blood pump is connected to the left ventricle or right ventricle of the human heart, and is connected to the aorta or pulmonary artery through the outflow pipeline. The pump is connected to a control driver (with a power supply device), and the blood pump is controlled by the control driver to deliver blood with a certain pressure (the general range is 80 - 120 mmHg) and flow rate (the general range is 2 - 10 L / min), sharing the power demand for the normal activities of the human body relative to the human heart.

[0004] Given the constraints of the operating environment for blood pumps, how to give them high integration and small volume characteristics while still fulfilling their functional requirements is a technical challenge of constant interest to those skilled in the art. [Overview of the project] [Problems that the invention aims to solve]

[0005] The objective of this invention is to provide a compact magnetic levitation centrifugal pump with a small volume. [Means for solving the problem]

[0006] This application provides a magnetic levitation centrifugal pump comprising a volute casing, a magnetostatic ring, and a rotor. The spiral casing has a levitation cavity, a medium inlet, and a medium outlet, the rotor is located inside the levitation cavity, and the magnetostatic ring is fixed to the spiral casing. The rotor includes a rotor body, a movable magnetic ring positioned on the rotor body, and at least two blades, wherein the movable magnetic ring is arranged coaxially and nested with the magnetostatic ring to restrict the radial position between the rotor body and the spiral casing. A magnetic steel assembly comprising N first magnetic steels arranged circumferentially is fixed to the rotor body, the magnetic poles of all the first magnetic steels are arranged alternately, and a magnetic member is further fixed to the rotor body, the magnetic member comprising at least one of a magnetic ring and an iron core. The spiral casing encloses a drive coil assembly that is provided relative to the magnetic steel assembly, and the drive coil assembly cooperates with the magnetic steel assembly to rotate the rotor body in the circumferential direction. A magnetic levitation coil assembly is fixed to the spiral casing, and when the magnetic levitation coil assembly is energized, an axial force is generated by the magnetic member and the magnetic levitation coil assembly.

[0007] The system optionally further includes a position sensor for detecting the axial position of the rotor body, Or / and adjacent first magnetic steels are in close contact, or the magnetic steel assembly further includes transversely magnetoconducting magnetic steels located between two of the first magnetic steels, and all of the magnetoconducting magnetic steels and all of the first magnetic steels form a Halbach magnetic steel array.

[0008] Selectively, the magnetic steel assembly and the magnetic member are provided at the first and second ends of the rotor body, respectively, and the drive coil assembly and the magnetic levitation coil assembly are provided at the first and second ends of the spiral casing, respectively.

[0009] The spiral casing may optionally have a first annular housing and a second annular housing in its inner cavity, the first annular housing and the second annular housing located at the first and second ends of the spiral casing, respectively, the first annular housing and the spiral casing enclose a first sealed cavity containing the drive coil, the second annular housing and the spiral casing enclose a second sealed cavity containing the magnetic levitation coil assembly, the levitation cavity formed between the first annular housing and the second annular housing, both of which are ceramic structures, the drive coil assembly positioned in contact with the first annular housing, and the magnetic levitation coil positioned in contact with the second annular housing.

[0010] Selectively, the rotor body includes an annular body and a base, both fixedly connected and positioned along the axial direction, with a liquid outlet between the annular body and the base, a central through-hole in the annular body communicating with the liquid outlet, the central through-hole coaxial with the medium inlet, each of the blades positioned between the annular body and the base, the magnetic steel assembly enclosed within the annular body, and the movable magnetic ring and the magnetic member enclosed within the base.

[0011] Selectively, the base has an annular encapsulation cavity, the movable magnetic ring is fitted to the inner annular wall of the annular encapsulation cavity, the magnetic member encapsulated in the base is located around the movable magnetic ring, and along the radial direction, the axial height of the intermediate region of the annular encapsulation cavity is greater than the axial height of the peripheral region.

[0012] Optionally, the configuration further includes a base and a cover, the cover having a cylinder with one end open and a guide cone connected to the other end of the cylinder, the opening of the cylinder being circumferentially engaged with the base in a sealable manner, the magnetostatic ring being fixed to the base via a threaded member and located inside the cylinder, and the base being circumferentially connected to the threads of the spiral casing and coaxial with the medium inlet, and the guide cone passing through the central hole of the annular sealing cavity and projecting toward the medium inlet.

[0013] Selectively, a first auxiliary passage is formed between the outer circumferential surface and outer end surface of the annular body and the corresponding inner wall of the spiral casing; a second auxiliary passage is formed between both the outer circumferential surface and outer end surface of the annular containment cavity and the corresponding inner wall of the spiral casing, and between the inner circumferential wall of the annular containment cavity and the cover; and both the outer end surface of the annular body and the outer end surface of the base have a predetermined angle with respect to the horizontal plane, and the distance from the outer end surface to the horizontal plane increases from the outside to the inside.

[0014] The annular body and the base's outer end faces are each provided with several projections, the projections extending from the inner edge to the outer edge, and the projections having a predetermined angle of attachment in the radial direction, the distance between adjacent projections decreasing as they approach the inner edge, or the height of the projections decreasing as they approach the inner edge.

[0015] Selectively, the rotor is a centrifugal, fully enclosed rotor structure, the blades are swept-back blades, the magnetic steel assembly and the magnetic member are provided at the first and second ends of the rotor body, respectively, and the blades are located between the magnetic steel assembly and the magnetic member. or / and the magnetic member includes a magnetic ring. In this invention, the rotational drive and axial position control of the rotor are completely independent and located on opposite sides of the rotor body, respectively, resulting in a simple control logic. Furthermore, in this invention, complete levitation of the rotor is achieved by the magnetic force between the movable magnetic ring and the magnetostatic ring. This eliminates mechanical contact between the rotor and the spiral casing (corresponding to the stator), reducing heat generation and wear, minimizing the possibility of thrombus formation and the crushing and destruction of blood cells. The radial levitation limit of the rotor can be achieved by relying on the movable magnetic ring and the magnetostatic ring. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram of the three-dimensional structure of a magnetic levitation centrifugal pump in one embodiment of the present invention. [Figure 2] This is a three-dimensional cross-sectional view of a magnetic levitation centrifugal pump. [Figure 3] Figure 1 is a schematic diagram of the cross-sectional structure. [Figure 4] This is a schematic diagram of the rotor structure in one embodiment of the present invention. [Figure 5] Figure 4 is a schematic diagram of a cross-section of the rotor from a different viewpoint. [Figure 6] This is a schematic diagram of the structure of the rotor body in one embodiment of the present invention. [Figure 7] This is a schematic diagram of a rotor in another embodiment of the present invention. [Figure 8] This is a schematic diagram of a rotor in another embodiment of the present invention. [Explanation of symbols]

[0017] 100... Rotor, 11... Base, 111... Lower cover plate, 112... Annular sealed cavity, 113... Inner peripheral wall, 12... Annular body, 121... Upper cover plate, 1211... Outer end face, 1212... Projection, 13... Blade, 14... Magnetic steel assembly, 15... Magnetic member, 16... Movable magnetic ring, 17... Magnetic member 200... Volute casing, 201... First volute casing, 202... Second volute casing, 203... First annular housing, 204... Second annular housing, 21... Drive coil assembly, 211... Drive coil, 212... Operating iron core, 22... Static magnetic ring, 23... Base, 24... Cover, 241... Cylinder, 242 Guide cone, 26... Position sensor, 27 Magnetic levitation coil assembly, 271... Magnetic levitation coil, 272... Magnetic levitation iron core 300... Inlet pipe 400... Outlet pipe 1a... First auxiliary flow path, 1b... Second auxiliary flow path, 100a... Liquid outlet

Embodiments for Carrying out the Invention

[0018] In the description of this application, the orientation or positional relationship indicated by terms such as "left", "right", "up", "down", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for facilitating the explanation of the simplification of the technology, and does not indicate or imply that the shown device or element necessarily has a specific orientation and is configured and operated in a specific orientation. Therefore, it cannot be understood as limiting this application. Furthermore, terms such as "first", "second", etc. are only used to describe two or more structures or members with the same or similar structures and / or functions, and do not mean any special limitation on the order and / or importance

[0019] Without losing generality, this specification introduces technical solutions and technical effects using the application of a magnetic levitation centrifugal pump to a cardiac blood pump as an example. Those skilled in the art will understand that the magnetic levitation centrifugal pump described herein is a technical solution proposed based on research into blood pumps, but that the magnetic levitation centrifugal pump described herein is not limited to application to cardiac blood pumps, and applications in other fields also fall within the scope of protection of this specification.

[0020] To better understand the technical solution of this application, the present application will be described in more detail below with reference to the attached drawings and specific embodiments.

[0021] Referring to Figures 1 to 3, Figure 1 is a schematic diagram of the three-dimensional structure of a magnetic levitation centrifugal pump in one embodiment of the present invention. Figure 2 is a three-dimensional cross-sectional view of the magnetic levitation centrifugal pump. Figure 3 is a schematic diagram of the cross-sectional structure of Figure 1.

[0022] This invention proposes a magnetic levitation centrifugal pump comprising a volute casing, a magnetostatic ring, and a rotor, wherein the volute casing has a levitation cavity, a medium inlet, and a medium outlet, and the rotor is located inside the levitation cavity.

[0023] Here, the spiral casing may include a first spiral casing 201 and a second spiral casing 202, which together enclose the rotor mounting space, and the first spiral casing 201 and the second spiral casing 202 can be detachably mounted to facilitate the mounting and maintenance of components such as the rotor. The first spiral casing 201 may be provided with a medium inlet, and the medium outlet may be formed by the corresponding structures on the first spiral casing 201 and the second spiral casing 202 enclosing it together. An inlet pipe 300 is attached to the medium inlet, and an outlet pipe 400 is attached to the medium outlet, and the first spiral casing 201, the second spiral casing 202, the inlet pipe 300, and the outlet pipe 400 may all be made of titanium alloy material.

[0024] Referring further to Figures 4 and 5, Figure 4 is a schematic diagram of the rotor structure in one embodiment of the present invention. Figure 5 is a schematic diagram of another view of the rotor shown in Figure 4.

[0025] The rotor in this application includes a rotor body, blades 13, a movable magnetic ring 16, a magnetic member 17, and a magnetic steel assembly 14.

[0026] Here, the rotor body primarily provides a mounting base for attaching other components that make up the rotor and is assembled to match the spiral casing. The specific structure of the rotor body is described below. The movable magnetic ring 16, blades 13, magnetic member 17, and magnetic steel assembly 14 are all attached to the rotor body, and the number of blades 13 may be two or more, i.e., there are at least two blades, and each blade is distributed along the circumferential direction, and the blades 13 may be swept-back fins, which provide optimized fluid efficiency, shear force and streamline distribution, and allow for smaller diameters of the rotor and spiral casing for the same output flow rate and pressure requirements, lower requirements for motor rotation speed and torque, and reduce the volume of the spiral casing, rotor and motor, enabling miniaturization of the pump while minimizing the possibility of hemolysis and thrombosis for the same output capacity.

[0027] Here, the number of blades 13 can be determined according to the volume of the pump body, and is usually 3 to 7 blades. For example, in this particular example, the number of blades is 5.

[0028] Naturally, blade 13 may be a blade of the same thickness or a straight blade, as long as it meets the usage needs.

[0029] A magnetostatic ring 22 is attached to the spiral casing 200, and the magnetostatic ring 22 is arranged coaxially and nested with a movable magnetic ring 16 to restrict the radial position between the rotor 100 and the spiral casing 200. Both the magnetostatic ring 22 and the movable magnetic ring 16 may include two or more annular magnets arranged along the axial direction. Figure 3 shows a specific example in which both the magnetostatic ring 22 and the movable magnetic ring 16 have three annular magnetic rings, with the movable magnetic ring 16 nested around the magnetostatic ring 22. Naturally, the number of annular magnetic rings in the magnetostatic ring 22 and the movable magnetic ring 16 is not limited to the description herein and may be other numbers.

[0030] The principle by which the radial position of the rotor relative to the spiral casing 200 is limited by the movable magnetic ring 16 and the magnetostatic ring 22 during operation is as follows: Radial levitation of the rotor is achieved by relying on the repulsive force between the movable magnetic ring and the magnetostatic ring. As described above, a pair of movable magnetic rings is attached to the rotor body and a pair of magnetostatic rings is attached to the spiral casing, and both the movable magnetic ring and the magnetostatic ring constitute a permanent magnet radial levitation bearing. The magnetostatic ring can be adjusted in axial position via precision threads between the base 23 and the spiral casing 200. Ideally, by adjusting the position of the magnetostatic ring 22, when the rotor body levitates axially to the middle of the levitation cavity of the spiral casing, the axial positions of the magnetostatic ring 22 and the movable magnetic ring 16 are perfectly aligned. At this time, the radial stiffness of the permanent magnet radial levitation bearing formed by the movable magnetic ring 16 and the magnetostatic ring 22 is maximized, and the axial force is zero.

[0031] A magnetic steel assembly 14 is fixed to the first end of the rotor body provided in this application, including N first magnetic steels 141 arranged circumferentially, with the magnetic poles of all the first magnetic steels 141 alternating, and referring to Figure 4, in the magnetic steel assembly, the first magnetic steels are formed around the circumference according to an alternating arrangement of N poles and S poles. Each magnetic steel of the magnetic steel assembly 14 may be sealed inside the rotor body. Herein, in one example, the first magnetic steels 141 can be in close contact with each other to form a magnetic ring of a full pole arc, thereby enabling a disk motor formed with a drive coil assembly 21 attached to a spiral casing 200 to obtain high motor efficiency.

[0032] Naturally, the magnetic steel assembly 14 may further include transversely magnetically conductive magnetic steel 18, which are located between the first magnetic steels 141, i.e., the same number of mutually exclusive transversely magnetically conductive magnetic steels 18 are arranged between the first magnetic steels 141, which have alternating magnetic poles. For example, 10 sets of first magnetic steels and magnetically conductive magnetic steels are arranged alternately to form a Halbach magnetic steel array (which may be an even number of sets from 4 to 16, with 10 sets being a selectable solution). Such a magnetic steel array can exert a magnetic concentration effect, improving the magnetic density between the motor air gaps with the same volume of magnetic steel, thereby further improving motor efficiency.

[0033] Naturally, the installation of the magnetic steel assembly 14 is not limited to the method described herein, but may be done in any other way, as long as it can achieve the functions described herein.

[0034] Correspondingly, a drive coil assembly 21 is enclosed in the first end of the spiral casing 200 that corresponds to the magnetic steel assembly 14 attached to the rotor, where the drive coil assembly 21 may include a drive coil 211 and an operating core 212. During operation, current is passed through the drive coil 211 to generate a magnetic field, the operating core 212 amplifies the magnetic field generated by the drive coil 211, and the first magnetic steel 141, in which the magnetic poles of the magnetic steel assembly 14 attached to the rotor body are arranged alternately, generates rotational force to drive and rotate the rotor body. The drive coil assembly 21 and the magnetic steel assembly 14 attached inside the rotor body form a disk motor.

[0035] When the magnetic levitation coil assembly 27 is energized, an axial force is generated by the magnetic member 17 and the magnetic levitation coil assembly 27 to control the axial position of the rotor body. By adjusting the direction of the current in the magnetic levitation coil assembly 27, the direction of the force between the magnetic levitation coil assembly 271 and the magnetic member 17 can be changed. The magnetic levitation coil assembly 27 may include a magnetic levitation coil 271 and a magnetic levitation core 272. Here, the axial position of the rotor body can be determined by a position sensor.

[0036] In this embodiment, the rotational drive and axial position control of the rotor are completely independent and located on opposite sides of the rotor body, respectively, and the control logic is simple. Furthermore, in this application, the magnetic force between the movable magnetic ring 16 and the magnetostatic ring 22 enables complete levitation of the rotor, thereby eliminating mechanical contact between the rotor 100 and the spiral casing 200 (corresponding to the stator), reducing heat generation and wear, minimizing the possibility of thrombus formation and the possibility of blood cells being crushed and destroyed, and the radial levitation limit of the rotor 100 can be achieved by relying on the movable magnetic ring and the magnetostatic ring.

[0037] In this specific example, the inner cavity of the spiral casing 200 contains a first annular housing 203 and a second annular housing 204, the first annular housing 203 and the second annular housing 204 located at the first and second ends of the spiral casing, respectively, the first annular housing 203 and the spiral casing surround a first sealed cavity for enclosing the drive coil, the second annular housing and the spiral casing surround a second sealed cavity for enclosing the magnetic levitation coil assembly, the levitation cavity is formed between the first annular housing and the second annular housing, both the first annular housing 203 and the second annular housing 204 are of ceramic construction, the drive coil assembly 21 is positioned in contact with the first annular housing 203 and the magnetic levitation coil 271 is positioned in contact with the second annular housing 204.

[0038] Each annular housing may be fixed to the spiral casing by adhesive or other means. Ceramic materials exhibit excellent compatibility with blood, and because they are very hard and insulating, the thickness of the annular housing can be thin, and the drive coil can be in close contact with the inner wall. This significantly reduces the air gap between the drive coil and the first magnetic steel, completely eliminating eddy current losses. A Halbach array can be used for the first magnetic steel, improving motor efficiency and enabling miniaturization of the blood pump without changing the maximum output capacity. The insulating properties of the ceramic minimize the risk of leakage current from the drive coil into the blood flowing through the spiral casing, and eliminate the possibility of the operation of the disk motor formed by the drive coil assembly and the first magnetic steel assembly being interfered with by an external electric field. For example, when a patient undergoes electroshock / electrodefibrillation / electrotome cutting treatment, the magnetic levitation centrifugal pump can still operate normally.

[0039] In one example, the rotor body includes an annular body 12 and a base 11, both of which are fixedly connected along the axial direction, each blade is located between the annular body 12 and the base 11, and there is a liquid outlet between the annular body 12 and the base 11, which may be located between two blades, the central through hole of the annular body 12 communicates with the liquid outlet 100a, and the interiors of both the annular body 12 and the base 11 are sealed with magnetic steel assemblies, and the movable magnetic ring 16 is sealed inside the base 11. Both the annular body 12 and the base are fixedly connected along the axial direction, and there is a liquid outlet between the annular body 12 and the base 11, the central through hole of the annular body 12 communicates with the liquid outlet, and the central through hole of the annular body 12 is coaxial with the medium inlet. Here, there may be multiple liquid outlets 100a, which are uniformly arranged along the circumferential direction, and the specific number can be determined according to the specific product and is not limited herein.

[0040] Specifically, the base has an annular encapsulation cavity, the movable magnetic ring is fitted to the inner annular wall of the annular encapsulation cavity, the magnetic member encapsulated in the base is located around the movable magnetic ring, and along the radial direction, the axial height of the intermediate region of the annular encapsulation cavity is greater than the axial height of the peripheral region.

[0041] This minimizes the space occupied by the sealing cavity in the fluid space inside the pump, which is advantageous for making the structure more compact. To facilitate installation, the annular sealing cavity may be formed in the following manner: an annular groove is provided in the base, and the lower cover plate 111 covers the opening of the annular groove to form a sealed cavity. By the same principle, the sealed cavity for attaching the magnetic steel assembly to the annular body can also be formed using a method in which the annular groove and the upper cover plate 121 cooperate to form a seal.

[0042] The rotor in this application may be a centrifugal, fully enclosed rotor. When the centrifugal pump is operating, a large volume of blood flows into the centrifugal pump through the inlet passage, is accelerated by the centrifugal blades of the rotor, and then flows out through the outlet passage, injecting the blood into the aorta to provide pressure and flow rate to the systemic blood circulation. The rotor centrifugal blades may have a hollow structure.

[0043] In each of the above embodiments, the magnetostatic ring may be mounted inside the spiral casing in the following manner. In one example, the magnetic levitation centrifugal pump further includes a base and a cover 24 engaged with the base 23, the cover 24 and the base being sealed together, and the magnetostatic ring being fixed to the base via a threaded member, the threaded member being a screw, bolt, or other component. The magnetostatic ring is mounted in a mounting space formed by the cover and the base, and a mounting through-hole is provided at the second end of the spiral casing, the mounting through-hole is coaxial with the medium inlet, and the threads of the base 23 are sealed together with the mounting through-hole. The cover 24 includes a cylinder 241 with one end open and a guide cone 242 connected to the other end of the cylinder, the magnetostatic ring 22 is located inside the cylinder 241, and the guide cone 242 protrudes toward the medium inlet through a central hole in the base 11. The guide cone 242 becomes smaller in the radial direction as it approaches the medium inlet. This ensures that the fluid at the medium inlet of the vortex casing flows uniformly circumferentially under the flow division of the guide cone, and further flows uniformly between the blades.

[0044] In the above embodiment, the base and the spiral casing are connected by screw threads, and the axial position of the base relative to the spiral casing can be precisely adjusted to work in precise cooperation with the movable magnetic ring in the rotor.

[0045] Referring to Figures 6 and 7, in each of the above embodiments, the outer end surface of the annular body 12 and the outer end surface of the base are each provided with several projections 1212 (only the projections on the outer end surface of the annular body are shown in the figures), the projections extend from the inner edge to the outer edge, and the projections 1212 have a predetermined angle with respect to the radial direction, the distance between adjacent projections decreases as they get closer to the inner edge, and the projections 1212 exhibit an internal helical structure. In this way, a hydrodynamic fluid levitation bearing is formed between the outer end surface of the annular body and the first annular housing, and between the outer end surface of the base and the second annular housing. When the rotor experiences very large axial interference and one end approaches the annular housing on that side, the hydrodynamic fluid levitation bearing can provide an additional center-directed restoring force, thereby improving the axial stability of the impeller.

[0046] Naturally, the closer the projection 1212 is to the inner edge, the lower its height becomes, and similarly, the above technical effects can be achieved, as shown in Figure 7. In one specific embodiment, a first auxiliary passage is formed between the outer circumferential surface and outer end surface of the annular body and the corresponding inner wall of the spiral casing, and a second auxiliary passage is formed between the outer circumferential surface and outer end surface of the annular sealing cavity and the corresponding inner wall of the spiral casing, and between the inner circumferential wall 113 of the annular sealing cavity and the cover 24.

[0047] During operation, the rotor floats in the middle of the volute casing 200 and rotates at high speed, and the blades between the annular body 12 and the base 11 and the inner wall of the volute casing 200 form the main flow path of the pump. Blood flows in from the medium inlet, passes through the central through-hole of the annular body into the main flow path between the blades, is accelerated by the rotation of the blades, then enters the main flow path inside the volute casing, and flows out of the volute casing through the medium outlet.

[0048] Furthermore, a small portion of the blood that enters the main flow path inside the vortex casing 200 flows back to the rotor body inlet through the first and second auxiliary passages, respectively, and after being accelerated again between the blades, it enters the interior of the vortex casing. With the above design, all the flow paths through which the blood entering the centrifugal pump flows are unidirectional, and there are no static or backflow areas, thereby minimizing the possibility of thrombus formation.

[0049] Furthermore, as described above, since the annular housing facing the end faces of the annular body and base is made of ceramic material, its surface is hard and smooth, and if the rotor and the annular housing come into unintentional contact, the surface of the annular housing is less likely to be damaged. Due to the higher motor efficiency, the thickness of the first magnetic steel inside the rotor can be made thinner under the same conditions, and accordingly, the thickness of the annular body 12 and the outer end walls (cover plates) of the base 11 can also be made thinner, thereby shortening the length of the backflow channel inside the spiral casing.

[0050] Furthermore, both the outer end face of the annular body and the outer end face of the base have a predetermined angle with respect to the horizontal plane, and the distance from the outer end face to the horizontal plane increases from the outside to the inside. That is, the outer end faces of the annular body and the base are concave inward, and the rotor has inwardly tapered surfaces on its upper and lower outer end faces. As a result, the outer gap of the auxiliary passage formed between the outer end face and the inner wall of the spiral casing is small, while the inner gap is large. In this way, when blood passes through the region with the small outer gap, the shear force is relatively high, the flow velocity is high, and the passage time is short, while when it passes through the region with the large inner gap... During this process, the flow velocity and shear force are relatively low, minimizing the possibility of hemolysis and thrombosis. This allows for a relatively smaller gap in the auxiliary passage, reducing backflow losses in the centrifugal pump and improving fluid efficiency. For the same output flow rate / pressure requirements of the centrifugal pump, the diameters of the rotor and volute casing can be reduced, lowering the requirements for motor rotation speed and torque. This reduces the volume of the volute casing / rotor, enabling miniaturization of the centrifugal pump while maintaining the same output capacity.

[0051] The above-mentioned position sensor can be either a Hall sensor or an eddy current sensor, as long as it can detect the axial position of the rotor body.

[0052] The magnetic levitation centrifugal pump provided in this application has been described in detail above. In this specification, the principle and embodiments of the present application have been described by applying specific individual examples, but the above description of embodiments is merely to help in understanding the method and core idea of ​​the present application. Notwithstanding the foregoing, those skilled in the art can make several improvements and modifications to the present application without departing from the principle, and these improvements and modifications are also within the scope of protection of the claims of this application.

Claims

1. Including a spiral casing, a magnetostatic ring, and a rotor, The spiral casing has a levitation cavity, a medium inlet, and a medium outlet, the rotor is located inside the levitation cavity, and the magnetostatic ring is fixed to the spiral casing. The rotor includes a rotor body, a movable magnetic ring positioned on the rotor body, and at least two blades, wherein the movable magnetic ring is arranged coaxially and nested with the magnetostatic ring to restrict the radial position between the rotor body and the spiral casing. A magnetic steel assembly comprising N first magnetic steels arranged circumferentially is fixed to the rotor body, the magnetic poles of all the first magnetic steels are arranged alternately, and a magnetic member is further fixed to the rotor body, the magnetic member comprising at least one of a magnetic ring and an iron core. The spiral casing encloses a drive coil assembly provided relative to the magnetic steel assembly, the drive coil assembly cooperates with the magnetic steel assembly to rotate the rotor body in the circumferential direction, a magnetic levitation coil assembly is fixed to the spiral casing, and when the magnetic levitation coil assembly is energized, an axial force is generated by the magnetic member and the magnetic levitation coil assembly. The spiral casing has an inner cavity containing a first annular housing and a second annular housing, the first annular housing and the second annular housing located at the first and second ends of the spiral casing, respectively, the first annular housing and the spiral casing surround a first sealed cavity enclosing the drive coil assembly, the second annular housing and the spiral casing surround a second sealed cavity enclosing the magnetic levitation coil assembly, the levitation cavity is formed between the first annular housing and the second annular housing, both the first and second annular housings are of a ceramic structure, the drive coil assembly is positioned in contact with the first annular housing, and the magnetic levitation coil of the magnetic levitation coil assembly is positioned in contact with the second annular housing. A magnetic levitation centrifugal pump characterized by the following features.

2. The system further includes a position sensor for detecting the axial position of the rotor body, or / and adjacent first magnetic steels are in close contact, or the magnetic steel assembly further includes transversely magnetoconducting magnetic steels located between two of the first magnetic steels, and all of the magnetoconducting magnetic steels and all of the first magnetic steels form a Halbach magnetic steel array. The magnetic levitation centrifugal pump according to feature 1.

3. The magnetic steel assembly and the magnetic member are provided at the first and second ends of the rotor body, respectively, and the drive coil assembly and the magnetic levitation coil assembly are provided at the first and second ends of the spiral casing, respectively. The magnetic levitation centrifugal pump according to feature 1.

4. The rotor body includes an annular body and a base, both of which are fixedly connected and arranged along the axial direction, and there is a liquid outlet between the annular body and the base, the central through-hole of the annular body communicates with the liquid outlet, the central through-hole is coaxial with the medium inlet, each of the blades is located between the annular body and the base, the magnetic steel assembly is sealed inside the annular body, and the movable magnetic ring and the magnetic member are sealed inside the base. A magnetic levitation centrifugal pump according to any one of claims 1 to 3.

5. The base has an annular encapsulation cavity, the movable magnetic ring is fitted to the inner annular wall of the annular encapsulation cavity, the magnetic member encapsulated in the base is located around the movable magnetic ring, and along the radial direction, the axial height of the intermediate region of the annular encapsulation cavity is greater than the axial height of the peripheral region. The magnetic levitation centrifugal pump according to feature 4.

6. The apparatus further includes a base and a cover, the cover having a cylinder with one end open and a guide cone connected to the other end of the cylinder, the opening of the cylinder being circumferentially engaged with the base in a sealable manner, the magnetostatic ring being fixed to the base via a threaded member and located inside the cylinder, and the base being circumferentially connected to the threads of the spiral casing and coaxial with the medium inlet, the guide cone passing through the central hole of the annular sealing cavity and projecting toward the medium inlet, The magnetic levitation centrifugal pump according to feature 5.

7. A first auxiliary passage is formed between the outer circumferential surface and outer end surface of the annular body and the corresponding inner wall of the spiral casing; a second auxiliary passage is formed between both the outer circumferential surface and outer end surface of the annular containment cavity and the corresponding inner wall of the spiral casing, and between the inner circumferential wall of the annular containment cavity and the cover; and both the outer end surface of the annular body and the outer end surface of the base have a predetermined angle with respect to the horizontal plane, and the distance from the outer end surface to the horizontal plane increases from the outside to the inside. The magnetic levitation centrifugal pump according to feature 6.

8. The outer end surfaces of the annular body and the base are each provided with several protrusions, the protrusions extending from the inner edge to the outer edge, and the protrusions having a predetermined angle of attachment in the radial direction, the distance between adjacent protrusions decreasing as they approach the inner edge, or the height of the protrusions decreasing as they approach the inner edge. The magnetic levitation centrifugal pump according to feature 4.

9. The rotor has a centrifugal, fully enclosed rotor structure, the blades are swept-back blades, the magnetic steel assembly and the magnetic member are provided at the first and second ends of the rotor body, respectively, and the blades are located between the magnetic steel assembly and the magnetic member. or / and the magnetic member includes a magnetic ring, A magnetic levitation centrifugal pump according to claim 1 or 2.

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