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) having a levitation cavity, a medium inlet and a medium outlet, the rotor (100) being located inside the levitation cavity, the static magnetic ring (22) being fixed to the volute casing (200), the rotor (100) including a rotor body and a movable magnetic ring (16) positioned on the rotor body, the movable magnetic ring (16) being coaxially and concentrically arranged with the static magnetic ring (22) so as to limit the radial position between the rotor body and the volute casing (200), the rotor body further having a magnetic steel assembly (14) including N first magnetic steels (141) arranged along the circumferential direction, the magnetic poles of all the first magnetic steels (141) being alternately arranged, drive coil assemblies (21) being further enclosed at both ends of the volute casing (200), the two drive coil assemblies (21) cooperating with the magnetic steel assembly (14) to provide an axial force and a rotational force for the rotor body to move along the axial direction. The magnetic steel assemblies (14) provided at both ends of the rotor (100) and the corresponding drive coil assemblies (21) on the volute casing (200) provide the axial force, without the need for additional coils and sensor assemblies, and can greatly reduce the volume and weight, thereby realizing high reliability and miniaturization of the blood pump.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the priority of the Chinese patent application filed with the China National Intellectual Property Administration on May 23, 2022, with the application number 202210565532.4 and the application title "Magnetic Levitation Centrifugal Pump", the entire content of which is incorporated into the present application by reference. TECHNICAL FIELD

[0002] The present application relates to the field of vibration reduction technology, in particular to a magnetic levitation centrifugal pump. BACKGROUND ART

[0003] Heart failure (abbreviated as "xin shuai" in Chinese) generally refers to the condition that a natural heart cannot pump enough blood flow to maintain systemic blood circulation. According to statistics from the World Health Organization (WTO), about 15% to 20% of people suffer from varying degrees of heart failure. The number of people over 65 years old hospitalized for 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 efficacy, and heart transplantation is extremely difficult due to the limitation of donor sources. Therefore, Ventricular Assist Device (VAD) has become a generally recognized and the most effective treatment option for various types of end-stage heart failure worldwide. The main component of a ventricular assist device is a blood pump. Generally, the inflow conduit of a blood pump is connected to the left ventricle or right ventricle of a human heart, and connected to the aorta or pulmonary artery through an outflow conduit. The pump is connected to a control driver (with power supply equipment). The blood pump, controlled by the control driver, delivers blood with a certain pressure (generally in the range of 80~120mmHg) and flow rate (generally in the range of 2~10L / min), sharing the power demand for normal human activities from the human heart. 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]

[0004] The objective of this invention is to provide a compact magnetic levitation centrifugal pump with a small volume. [Means for solving the problem]

[0005] 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 and a movable magnetic ring positioned on the rotor body, wherein the movable magnetic ring is arranged coaxially and nested within the magnetostatic ring so as to limit 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, and the magnetic poles of all the first magnetic steels are arranged alternately. Drive coil assemblies are further enclosed at both ends of the spiral casing, and the two drive coil assemblies cooperate with the magnetic steel assembly to provide axial and rotational forces that cause the rotor body to move along the axial direction.

[0006] The centrifugal pump provided in this invention provides axial limits through magnetic steel assemblies located at both ends of the rotor body and corresponding drive coil assemblies on the spiral casing, eliminating the need for additional coils and sensor assemblies, preventing additional power consumption for position control, and eliminating the need for sensor assemblies for axial position control. As a result, the centrifugal pump implanted in the body has no electronic components, is more resistant to interference, more reliable, and its performance does not degrade with extended operating time. Therefore, compared to existing technologies, this axial levitation technology enables high reliability and miniaturization of blood pumps.

[0007] 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.

[0008] The rotor body may be optionally provided with the magnetic steel assembly at both ends, the magnetic steel assemblies at both ends of the rotor body being symmetrical with respect to the central cross-section of the rotor body, the drive coil assemblies located at both ends of the spiral casing being symmetrical with respect to the central cross-section of the levitation cavity, and the magnetic steel assembly and the drive coil assembly on the same side forming a pair of disk motors, the disk motors at both ends together providing axial and rotational forces that move along the axial direction 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.

[0009] Selectively, a magnetic member is further sealed in at least one end of the rotor body, and a magnetic levitation coil is sealed in the corresponding end of the spiral casing, and when the magnetic levitation coil is energized, an axial force is generated between the magnetic levitation coil and the magnetic member, wherein the magnetic member includes at least one of an iron core or a second magnetic steel.

[0010] Selectively, the ends of the rotor body are each enclosed with the magnetic members, and the two magnetic members are symmetrical with respect to the central cross-section of the rotor body; and the ends of the spiral casing are each enclosed with the magnetic levitation coils, and the two magnetic levitation coils are symmetrical with respect to the central cross-section of the levitation cavity.

[0011] The number of magnetic members is selectable to be multiple, uniformly arranged along the circumferential direction, and the magnetic members are arranged between adjacent first magnetic steels. or / and, the magnetic member is superimposed on the first magnetic steel along the axial direction, Or / and, the magnetic levitation coil is positioned to overlap the drive coil assembly in the axial direction.

[0012] Optionally, the spiral casing has an annular housing in its inner cavity, the annular housing and the spiral casing enclose a sealed cavity, the drive coil assembly is located in the sealed cavity, the floating cavity is formed between two annular housings located at both ends, the annular housing is of a ceramic structure, and the drive coil assembly is positioned in contact with the annular housing.

[0013] Selectively, the rotor body includes an annular body and a base, both fixedly connected and arranged 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 being coaxial with the medium inlet, and a blade between the annular body and the base forming a fully enclosed rotor structure, with the magnetic steel assembly sealed inside both the annular body and the base, and the movable magnetic ring sealed inside the base.

[0014] Selectively, the base has a first annular encapsulation cavity, the movable magnetic ring is fitted into the inner annular wall of the first annular encapsulation cavity, and the first iron core and magnetic steel assembly 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 first annular encapsulation cavity is greater than the axial height of the peripheral region.

[0015] 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 first annular sealing cavity and projecting toward the medium inlet.

[0016] Selectively, a first auxiliary passage is formed between the outer peripheral wall and outer end wall of the annular body and the corresponding inner wall of the spiral casing; a second auxiliary passage is formed between the outer peripheral wall and outer end wall of the first annular containment cavity and the corresponding inner wall of the spiral casing; and between the inner peripheral wall of the first 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.

[0017] Optionally, a plurality of protrusions are provided on both the outer end face of the annular body and the outer end face of the base seat, the protrusions extend from an inner edge side to an outer edge side, have a predetermined included angle with respect to the radial direction, the distance between adjacent protrusions decreases as the distance to the inner edge side decreases, or the height of the protrusions decreases as the distance to the inner edge decreases, or / and the blades are swept-back blades.

[0018] Optionally, the rotor body is an annular housing, the number of magnetic steel assemblies is one, each of the first magnetic steels is enclosed in an inner cavity of the annular housing, each of the first magnetic steels extends from one end to the other end of the rotor body, at least two grooves are provided on an end face of the annular housing facing a medium inlet of a volute casing, openings of the grooves face the medium inlet of the volute casing, the grooves are located between adjacent first magnetic steels, and a main liquid flow channel of the rotor body is formed by the grooves. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0019] [Figure 1] It is a schematic diagram of a three-dimensional structure of a magnetically levitated centrifugal pump according to an embodiment of the present application. [Figure 2] It is a three-dimensional cross-sectional view of a magnetically levitated centrifugal pump. [Figure 3] It is a schematic diagram of the cross-sectional structure in Figure 1. [Figure 4] It is a schematic diagram of a structure of a rotor according to an embodiment of the present application. [Figure 5] It is a schematic diagram of the rotor shown in Figure 4 from another viewing angle. [Figure 6] It is a schematic diagram of a rotor according to another embodiment of the present application. [Figure 7] It is a schematic diagram of a rotor according to a further embodiment of the present application. [Figure 8] It is a schematic cross-sectional view of a magnetically levitated centrifugal pump according to a second embodiment of the present application. [Figure 9] It is a schematic cross-sectional view of the rotor shown in Figure 8 of the present application. [Figure 10] It is a schematic diagram of a rotor according to a further embodiment of the present application. [Figure 11] Figure 10 shows a local cross-sectional view of the rotor. [Explanation of symbols]

[0020] 100...Rotor, 11...Base, 111...Lower cover plate, 112...First annular sealing cavity, 113...Inner peripheral wall, 12...Annular body, 121...Upper cover plate, 1211...Outer end face, 1212...Protrusion, 13...Blade, 14...Magnetic steel assembly, 15...Magnetic member, 16...Movable magnetic ring, 18...Magnetic conductive magnetic steel, 100'...Rotor, 14...Magnetic steel assembly, 141...First magnetic steel, 110...Annular housing, 120...Groove body, 111'...Cover plate, 200...Spiral casing, 201...First spiral casing, 202...Second spiral casing, 203...First annular housing, 204...Second annular housing, 21...Drive coil assembly, 211...Drive coil, 212...Operating core, 22...Magnetic ring, 23...Base, 24...Guide cone, 25...Magnetic levitation coil 300...Inlet pipe, 400...Outlet pipe, 1a...first auxiliary passage, 1b...second auxiliary passage, 100a...liquid outlet. [Modes for carrying out the invention]

[0021] Furthermore, in the description of this application, directions or positional relationships indicated by terms such as "left," "right," "up," "down," "inside," and "outside" are based on the directions or positional relationships shown in the attached drawings and are merely for the purpose of simplifying the technical explanation. They do not necessarily indicate or imply that the shown devices or elements have a specific direction or are configured or operated in a specific direction, and therefore cannot be understood as limiting this application. In addition, terms such as "first," "second," etc., are used only to describe two or more structures or members that have the same or similar structure and / or function, and do not imply any special limitation on order and / or importance.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] This invention proposes a magnetic levitation centrifugal pump comprising a volute casing 200, a magnetostatic ring 22, and a rotor 100, wherein the volute casing 200 has a levitation cavity, a medium inlet, and a medium outlet, and the rotor 100 is located inside the levitation cavity.

[0026] Here, the spiral casing 200 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 may be provided with a medium inlet, and the medium outlet may be formed by the corresponding structures on the first and second spiral casings together. An inlet pipe is attached to the medium inlet, and an outlet pipe is attached to the medium outlet, and the first spiral casing, the second spiral casing, the inlet pipe, and the outlet pipe may all be made of titanium alloy material.

[0027] Referring 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.

[0028] The rotor in this application includes a rotor body, blades 13, a movable magnetic ring 16, and a magnetic steel assembly 14.

[0029] 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, blades, and magnetic steel assembly are all attached to the rotor body, and the number of blades may be two or more, i.e., there are at least two blades, each blade is distributed along the circumferential direction, and the blades may be swept-back fins, which provide optimized fluid efficiency, shear force, and streamline distribution, allowing for smaller diameters of the rotor and spiral casing for the same output flow rate and pressure requirements, lower requirements for motor rotational speed and torque, and reducing the volume of the spiral casing, rotor, and motor. This allows for miniaturization of the pump while maintaining the same output capacity, and minimizes the possibility of hemolysis and thrombosis.

[0030] Here, the number of blades can be determined according to the volume of the pump body, and is usually between 3 and 7 blades. For example, in this particular example, the number of blades is 5.

[0031] Naturally, the blade can be a blade of the same thickness or a straight blade, as long as it meets the usage needs.

[0032] A magnetostatic ring 22 is attached to the spiral casing, and the magnetostatic ring is arranged coaxially and nested with the movable magnetic ring 16 to restrict the radial position between the rotor and the spiral casing. Both the magnetostatic ring and the movable magnetic ring may include two or more annular magnets arranged along the axial direction. Figure 3 shows a specific example in which both the magnetostatic ring and the movable magnetic ring have three annular magnetic rings, with the movable magnetic ring nested around the magnetostatic ring. Naturally, the number of annular magnetic rings in the magnetostatic ring and the movable magnetic ring is not limited to the description herein and may be other numbers. 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 rings and the magnetostatic rings constitute a permanent magnet radial levitation bearing. The magnetostatic rings can be adjusted in axial position via precision threads between the base and the spiral casing, and the radial levitation of the rotor is achieved by relying on the repulsive force between the movable magnetic ring and the magnetostatic ring.

[0033] Both ends of the rotor body provided in this application are fixed with a magnetic steel assembly 14 containing N first magnetic steels 141 arranged circumferentially, the magnetic poles of all the first magnetic steels arranged alternately, and referring to Figure 4, the first magnetic steels in the magnetic steel assembly are formed around the circumference according to the alternating arrangement of N poles and S poles. Each magnetic steel in the magnetic steel assembly may be sealed inside the rotor body. Here, in one example, the first magnetic steels 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 attached to a spiral casing to obtain high motor efficiency.

[0034] Naturally, the magnetic steel assembly may further include transversely magnetically conductive magnetic steel 18, which is located between the first magnetic steels, i.e., an equal number of mutually exclusive transversely magnetically conductive magnetic steels are placed between the first magnetic steels with alternating magnetic poles, for example, by alternating 10 sets of first magnetic steels and magnetically conductive magnetic steels 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), and such a magnetic steel array can exert a magnetic concentration effect, improving the magnetic density between the motor air gap with the same volume of magnetic steel, thereby further improving motor efficiency.

[0035] Naturally, the installation of the magnetic steel assembly 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.

[0036] Correspondingly, the ends of the spiral casing corresponding to the magnetic steel assembly attached to the rotor each contain a drive coil assembly 21, which may include a drive coil 211 and an operating core 212. The drive coil assemblies at both ends may be arranged symmetrically with respect to the central cross-section of the levitation cavity, or, of course, asymmetrically. During operation, an alternating current is passed through the drive coil to generate a magnetic field. The operating core amplifies the magnetic field generated by the drive coil. The first magnetic steel, in which the magnetic poles of the magnetic steel assembly attached to the rotor body are alternately arranged, generates an axial force. The controller detects the difference in electromotive force or inductance fed back by the upper and lower drive coils, thereby confirming the difference in distance from the rotor to the upper and lower drive coil positions. By adjusting the drive parameters of the upper and lower drive coils (not limited to current, voltage, duty cycle, etc.), the magnitude of the axial force generated by the drive coils on the first magnetic steel in the rotor is changed, thereby controlling the axial position of the rotor. This causes the rotor body to float and operate at a central position where the distance to the upper and lower end walls of the spiral casing is always the same, under the action of the motor's axial electromagnetic force.

[0037] This levitation method eliminates the need for additional coils and sensor assemblies, significantly reducing volume and weight. Rotor body position control is achieved by adjusting the current of the upper and lower motors, eliminating additional power consumption due to position control. Axial position control does not require a sensor assembly, resulting in a centrifugal pump implanted in the body that is free of electronic equipment, offering greater resistance to interference, higher reliability, and performance that does not degrade with extended operating time. Therefore, compared to existing technologies, this axial levitation technology enables high reliability and miniaturization of blood pumps.

[0038] 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.

[0039] Referring to Figures 8 and 9, Figure 8 is a schematic cross-sectional view of a magnetic levitation centrifugal pump in a second embodiment of the present application, and Figure 9 is a schematic cross-sectional view of the rotor shown in Figure 8 of the present application.

[0040] To simplify the control logic, a magnetic member 15 is further sealed in at least one end of the rotor body in this application, and the attached drawings show a specific example in which magnetic members are sealed in both ends of the rotor body. The magnetic member may be at least one of an iron core or a second magnetic steel. A magnetic levitation coil 25 is further sealed in the corresponding end of the spiral casing, and when a DC current is passed through the magnetic levitation coil, an axial force is generated between the magnetic levitation coil and the magnetic member.

[0041] If magnetic members are sealed in both ends of the rotor body, the two magnetic members are symmetrical with respect to the central cross-section of the rotor body. Similarly, if magnetic levitation coils are sealed in both ends of the spiral casing, the two magnetic levitation coils are symmetrical with respect to the central cross-section of the levitation cavity. This symmetrical installation facilitates control.

[0042] In this configuration, the rotor body can be rotated by controlling the current in the drive coil, and the axial position of the rotor body can be adjusted by controlling the current in the magnetic levitation coil.

[0043] In one specific example, the number of magnetic members may be multiple, and they are uniformly arranged along the axial direction. The magnetic members are placed between adjacent first magnetic steels, and Figure 9 shows a specific embodiment in which the magnetic members and first magnetic steels are arranged alternately. The structure of the magnetic levitation centrifugal pump in this embodiment is compact.

[0044] Naturally, the magnetic members and the first magnetic steel can also be arranged in an overlapping manner along the axial direction.

[0045] In this specific example, an annular housing is located in the inner cavity of the spiral casing, and a sealed cavity is enclosed by the annular housing and the spiral casing, and the drive coil assembly is located in the sealed cavity, and naturally, in the above embodiment having a magnetic levitation coil, the magnetic levitation coil is also located in the sealed cavity. The levitation cavity is formed between the two annular housings at both ends, and in this specification, the annular housing attached to the first spiral casing is defined as the first annular housing 203, and the annular housing attached to the second spiral casing is defined as the second annular housing 204. In other words, the rotor body can move axially by reciprocating between the two annular housings, where the annular housing is a ceramic structure.

[0046] The annular housing may be fixed to the spiral casing by adhesive or other means.

[0047] 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.

[0048] Referring to Figures 6 and 7, Figure 6 is a schematic diagram of a rotor in another embodiment of the present application. Figure 7 is a schematic diagram of a rotor in yet another embodiment of the present application.

[0049] 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, and there is a liquid outlet 100a between the annular body 12 and the base 11, the central through hole of the annular body 12 communicates with the liquid outlet, each blade is located between the annular body 12 and the base 11, and magnetic steel assemblies are sealed inside both the annular body 12 and the base 11, and a movable magnetic ring is sealed inside the base 11. Both the annular body 12 and the base 11 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, the central through hole of the annular body 12 is coaxial with the medium inlet, the number of liquid outlets may be multiple and uniformly arranged along the circumferential direction, the specific number can be determined according to the specific product and is not limited herein.

[0050] Specifically, the base 11 has a first annular encapsulation cavity 111, the movable magnetic ring is fitted into the inner annular wall of the first annular encapsulation cavity, the first iron core and magnetic steel assembly encapsulated in the base 11 are located around the movable magnetic ring, and along the radial direction, the axial height of the intermediate region of the first annular encapsulation cavity is greater than the axial height of the peripheral region.

[0051] 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.

[0052] To facilitate installation, the first annular sealing cavity may be formed in the following manner: an annular groove is provided in the base 11, 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 12 can also be formed using a method in which the annular groove and the upper cover plate 121 cooperate to form a seal.

[0053] 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 inflow passage, is accelerated by the centrifugal blades of the rotor, and then flows out through the outflow 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.

[0054] Referring to Figures 10 and 11, in another specific embodiment, the rotor body 100' includes an annular housing 110, the number of magnetic steel assemblies 14 may be one, each first magnetic steel 141 is enclosed in the inner cavity of the annular housing 110, and the first magnetic steel 141 extends from one end to the other of the rotor body, with the north and south poles of the first magnetic steel 141 being close to both ends of the annular housing 110, respectively, and the spiral casing of the annular housing 110 The end face of the medium inlet facing the ring has at least two grooves 120, the openings of which face the medium inlet of the spiral casing, and the grooves 120 are located between adjacent first magnetic steels, and the grooves 120 form the main fluid flow path of the rotor body, that is, in this embodiment, the medium entering from the medium inlet of the spiral casing flows out through the grooves 120 to the medium outlet, and the rotor 100' may have a centrifugal semi-closed rotor structure. In this rotor, the mounting method of the movable magnetic ring 16 may be the same as in the above embodiment.

[0055] In each of the above embodiments, the magnetostatic ring may be mounted inside the spiral casing in the following manner.

[0056] In one example, a magnetic levitation centrifugal pump further includes a base and a cover engaged with the base, the cover and base being sealed and fixed together, and a 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 base, and a mounting through-hole is provided at the second end of the volute casing, the mounting through-hole is coaxial with the medium inlet, and the threads of the base are sealed and connected to the mounting through-hole. The cover includes a cylinder with one end open and a guide cone 24 connected to the other end of the cylinder, the magnetostatic ring is located inside the cylinder, and the guide cone protrudes toward the medium inlet through a central hole in the base 11. The radial size of the guide cone decreases closer to the medium inlet, so that the fluid at the medium inlet of the volute casing flows uniformly circumferentially under the flow division of the guide cone and further flows uniformly between the blades.

[0057] In the above embodiment, the base 23 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 so as to work precisely with the movable magnetic ring in the rotor.

[0058] Referring to Figure 9, in each of the above embodiments, the outer end surface 1211 of the annular body 12 and the outer end surface (not indicated) of the base 11 are each provided with several projections 1212, the projections extending from the inner edge to the outer edge, and having a predetermined angle with respect to the radial direction, the distance between adjacent projections decreasing as they approach the inner edge, and the projections exhibit an internal helical structure. In this way, a hydrodynamic fluid levitation bearing is formed between the outer end surface of the annular body 12 and the upper annular housing, and between the outer end surface of the base 11 and the lower 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.

[0059] Referring to Figure 10, it is clear that the closer the protrusion is to the inner edge, the lower its height becomes, and similarly, the above technical effects can be achieved.

[0060] In one specific embodiment, a first auxiliary passage is formed between the outer peripheral wall and outer end wall of the annular body 12 and the corresponding inner wall of the spiral casing, and a second auxiliary passage is formed between the outer peripheral wall and outer end wall of the first annular containment cavity and the corresponding inner wall of the spiral casing, and between the inner peripheral wall 113 of the first annular containment cavity and the cover.

[0061] During operation, the rotor floats in the middle of the spiral casing and rotates at high speed, and the blades between the annular body 12 and the base 11, and the inner wall of the spiral casing 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 12 into the main flow path between the blades, is accelerated by the rotation of the blades, then enters the main flow path inside the spiral casing, and flows out of the spiral casing through the medium outlet.

[0062] Furthermore, a small portion of the blood that enters the main flow channel inside the vortex casing flows back to the rotor body inlet through the first auxiliary passage 1a and the second auxiliary passage 1b, respectively, and after being accelerated again between the blades, it enters the inside of the vortex casing. With the above design, all the flow channels through which the blood entering the centrifugal pump flows are unidirectional, and there are no static or backflow regions, thereby minimizing the possibility of thrombus formation.

[0063] Furthermore, as described above, since the annular housing facing the end faces of the annular body 12 and base 11 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 outer end walls (cover plates) of the annular body 12 and base 11 can also be made thinner, thereby shortening the length of the backflow channel inside the spiral casing.

[0064] Furthermore, both the outer end surface of the annular body 12 and the outer end surface of the base 11 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. That is, the outer end surfaces of the annular body 12 and the base 11 are concave inward, and the rotor has inwardly tapered surfaces on its upper and lower outer end surfaces. As a result, the outer gap of the auxiliary passage formed between the outer end surface and the inner wall of the spiral casing is small, and the inner gap is large. In this case, when blood passes through the region with a small outer gap, the shear force is relatively high, the flow velocity is high, the passage time is short, and the inner gap is large. When passing through the region, 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, and the requirements for motor rotational speed and torque can be lowered. This reduces the volume of the volute casing / rotor, enabling miniaturization of the centrifugal pump while maintaining the same output capacity.

[0065] 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 and a movable magnetic ring positioned on the rotor body, wherein the movable magnetic ring is arranged coaxially and nested within the magnetostatic ring so as to limit the radial position between the rotor body and the spiral casing. A magnetic steel assembly comprising N first magnetic steels arranged circumferentially is further fixed to the rotor body, and the magnetic poles of all the first magnetic steels are arranged alternately. Drive coil assemblies are enclosed at both axial ends of the spiral casing, and the two drive coil assemblies cooperate with the magnetic steel assembly to provide axial and rotational forces that cause the rotor body to move along the axial direction. A magnetic member is further sealed in at least one axial end of the rotor body, and a magnetic levitation coil is sealed in the corresponding end of the spiral casing. When the magnetic levitation coil is energized, an axial force is generated between the magnetic levitation coil and the magnetic member, where the magnetic member includes at least one of an iron core or a second magnetic steel. The axial ends of the rotor body are both enclosed with the magnetic members, and the two magnetic members are symmetrical with respect to the central cross-section of the rotor body; the axial ends of the spiral casing are both enclosed with the magnetic levitation coils, and the two magnetic levitation coils are symmetrical with respect to the central cross-section of the levitation cavity. A magnetic levitation centrifugal pump characterized by the following features.

2. The axial ends of the rotor body are each provided with the magnetic steel assembly, the magnetic steel assemblies at both ends of the rotor body are symmetrical with respect to the central cross-section of the rotor body, the drive coil assemblies located at both ends of the spiral casing are symmetrical with respect to the central cross-section of the levitation cavity, and the magnetic steel assembly and the drive coil assembly on the same side form a pair of disk motors, and the disk motors at both ends together provide axial force and rotational force that move along the axial direction of the rotor body. Or / and adjacent first magnetic steels are in close contact, or the magnetic steel assembly further includes transverse magnetoconducting magnetic steels located between two of the first magnetic steels, and all of the transverse 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 number of the magnetic members is multiple, and they are uniformly arranged along the circumferential direction, and the magnetic members are arranged between adjacent first magnetic steels. Alternatively, the magnetic member is superimposed with the first magnetic steel along the axial direction. or / and, the magnetic levitation coil is positioned to overlap the drive coil assembly in the axial direction. The magnetic levitation centrifugal pump according to feature 1.

4. An annular housing is located in the inner cavity of the spiral casing, and a sealed cavity is enclosed by the annular housing and the spiral casing, the drive coil assembly is located in the sealed cavity, the floating cavity is formed between two annular housings located at both ends, the annular housing is of a ceramic structure, and the drive coil assembly is positioned in contact with the annular housing. A magnetic levitation centrifugal pump according to claim 1 or 2.

5. 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, and there is a blade between the annular body and the base to form a fully enclosed rotor structure, the magnetic steel assembly is sealed inside both the annular body and the base, and the movable magnetic ring is sealed inside the base. The magnetic levitation centrifugal pump according to feature 2.

6. The base has a first annular encapsulation cavity, the movable magnetic ring is fitted into the inner annular wall of the first annular encapsulation cavity, and the first iron core and magnetic steel assembly 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 first annular encapsulation cavity is greater than the axial height of the peripheral region of the first annular encapsulation cavity. The magnetic levitation centrifugal pump according to feature 5.

7. 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 spiral casing by threads and coaxial with the medium inlet, the guide cone passing through the central hole of the first annular sealing cavity and protruding toward the medium inlet, The magnetic levitation centrifugal pump according to feature 6.

8. A first auxiliary passage is formed between the outer peripheral wall and outer end wall of the annular body and the corresponding inner wall of the spiral casing, a second auxiliary passage is formed between the outer peripheral wall and outer end wall of the first annular containment cavity and the corresponding inner wall of the spiral casing, and between the inner peripheral wall of the first 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 7.

9. The axial outer end faces 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 radial direction of the protrusions having a predetermined angle, 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. or / and the blade is a swept wing, The magnetic levitation centrifugal pump according to feature 5.

10. The rotor body is an annular housing, and there is one magnetic steel assembly, each of the first magnetic steels enclosed in the inner cavity of the annular housing, each of the first magnetic steels extending from one axial end to the other of the rotor body, and the end face of the annular housing facing the medium inlet of the spiral casing has at least two grooves, the openings of the grooves facing the medium inlet of the spiral casing, the grooves are located between adjacent first magnetic steels, and the grooves form the main fluid flow path of the rotor body. The magnetic levitation centrifugal pump according to feature 1.

11. 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 and a movable magnetic ring positioned on the rotor body, wherein the movable magnetic ring is arranged coaxially and nested within the magnetostatic ring so as to limit the radial position between the rotor body and the spiral casing. A magnetic steel assembly comprising N first magnetic steels arranged circumferentially is further fixed to the rotor body, and the magnetic poles of all the first magnetic steels are arranged alternately. Drive coil assemblies are enclosed at both axial ends of the spiral casing, and the two drive coil assemblies cooperate with the magnetic steel assembly to provide axial and rotational forces that cause the rotor body to move along the axial direction. An annular housing is located in the inner cavity of the spiral casing, and a sealed cavity is enclosed by the annular housing and the spiral casing, the drive coil assembly is located in the sealed cavity, the floating cavity is formed between two annular housings located at both ends, the annular housing is of a ceramic structure, the drive coil assembly includes a drive coil and an operating core, the drive coil is positioned in contact with the annular housing, A magnetic levitation centrifugal pump characterized by the following features.

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