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 the application number 202210565543.2 and the 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 a magnetic levitation centrifugal pump.

Background Art

[0003] Heart failure (abbreviated as "heart failure" in Chinese), simply speaking, means that the natural heart cannot pump enough blood to maintain the body's blood circulation. According to the statistics of the World Health Organization (WHO), about 15% - 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 (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. 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 human heart during normal human activities.

[0004] In view of the restrictions on the usage environment of blood pumps, on the premise of meeting their functions, how to endow blood pumps with the characteristics of high integration and small volume has always been a highly concerned technical issue for those skilled in the art.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present application is to provide a small-sized and compact magnetic levitation centrifugal pump.

Means for Solving the Problems

[0006] The present application provides a magnetic levitation centrifugal pump, which includes a volute casing, a static magnetic ring, and a rotor. The volute casing has a floating cavity, a medium inlet, and a medium outlet. The rotor is located inside the floating cavity. The static magnetic ring is fixed to the volute casing. The rotor includes a rotor body, a movable magnetic ring positioned on the rotor body, and at least two blades. The movable magnetic ring is coaxially and concentrically arranged with the static magnetic ring so as to limit the radial position between the rotor body and the volute casing. A magnetic steel assembly including N first magnetic steels arranged along the circumferential direction is fixed to the rotor body. The magnetic poles of all the first magnetic steels are arranged alternately. A magnetic member is further fixed to the rotor body. The magnetic member includes at least one of a magnetic ring and an iron core. A drive coil assembly provided relative to the magnetic steel assembly is enclosed in the volute casing. 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 volute casing. When the magnetic levitation coil assembly is energized, an axial force is generated by the magnetic member and the magnetic levitation coil assembly.

[0007] Optionally, it further includes a position sensor for detecting the axial position of the rotor body. Or / and, whether the adjacent first magnetic steels are in close contact, or the magnetic steel assembly further includes a lateral magnetic conduction magnetic steel located between the two first magnetic steels, and a Halbach magnetic steel array is formed by all the magnetic conduction magnetic steels and all the first magnetic steels.

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

[0009] Optionally, there are a first annular housing and a second annular housing in the inner cavity of the scroll casing. The first annular housing and the second annular housing are respectively located at the first end and the second end of the scroll casing. A first sealed cavity for enclosing the drive coil is surrounded by the first annular housing and the scroll casing, and a second sealed cavity for enclosing the magnetic levitation coil assembly is surrounded by the second annular housing and the scroll casing. The levitation cavity is formed between the first annular housing and the second annular housing. Both the first annular housing and the second annular housing are of ceramic structure. The drive coil assembly is arranged in contact with the first annular housing, and the magnetic levitation coil is arranged in contact with the second annular housing.

[0010] Optionally, the rotor body includes an annular body and a pedestal, and the two are fixedly connected and arranged along the axial direction. There is a liquid outlet between the annular body and the pedestal. The central through hole of the annular body communicates with the liquid outlet. The central through hole is coaxial with the medium inlet. Each blade is located between the annular body and the pedestal. The magnetic steel assembly is enclosed inside the annular body, and the movable magnetic ring and the magnetic member are enclosed inside the pedestal.

[0011] Optionally, the pedestal has an annular enclosed cavity, the movable magnetic ring is fitted on the inner ring wall of the annular enclosed cavity, the magnetic member enclosed in the pedestal is located around the movable magnetic ring, and along the radial direction, the axial height of the intermediate region of the annular enclosed cavity is greater than the axial height of the edge region.

[0012] Optionally, it further includes a base and a cover. The cover has a cylinder with one end open and a guide cone connected to the other end of the cylinder. The opening of the cylinder is hermetically engageable with the base along the circumferential direction. The static magnetic ring is fixed to the base via a threaded member and is located inside the cylinder. And the base is hermetically connectable to the thread of the volute casing and is coaxial with the medium inlet. The guide cone penetrates the central hole of the annular enclosed cavity and protrudes towards the medium inlet.

[0013] Optionally, a first auxiliary passage is formed between the outer peripheral surface and the outer end surface of the annular body and the corresponding inner wall of the volute casing. A second auxiliary passage is formed between both the outer peripheral surface and the outer end surface of the annular enclosed cavity and the corresponding inner wall of the volute casing, and between the inner peripheral wall of the annular enclosed cavity and the cover. And both the outer end surface of the annular body and the outer end surface of the pedestal have a predetermined included angle with respect to the horizontal plane, and from the outside to the inside, the distance from the outer end surface to the horizontal plane increases.

[0014] Optionally, several protrusions are provided on both the outer end surface of the annular body and the pedestal. The protrusions extend from the inner edge side to the outer edge side, and the protrusions have a predetermined included angle with respect to the radial direction. The distance between adjacent protrusions becomes smaller as it is closer to the inner edge side, or the height of the protrusions becomes lower as it is closer to the inner edge.

[0015] Optionally, the rotor has a centrifugal fully enclosed rotor structure, the blade is a retreating blade, the magnetic steel assembly and the magnetic member are respectively provided at the first end and the second end of the rotor body, and the blade is located between the magnetic steel assembly and the magnetic member. Or / and, the magnetic member includes a magnetic ring. In this application, the rotational drive and the axial position control of the rotor are completely independent and are respectively located on both sides of the rotor body, and the control logic is simple. Also, in this application, due to the magnetic force action between the movable magnetic ring and the static magnetic ring, the complete floating operation of the rotor is realized. In this way, there is no mechanical contact between the rotor and the volute casing (equivalent to the stator), reducing heat generation and wear, minimizing the possibility of thrombus formation and the possibility of blood cells being crushed and destroyed. The radial floating limit of the rotor can be realized depending on the movable magnetic ring and the static magnetic ring.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Explanation of Reference Signs

[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... Protrusion, 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 the present 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 description of the simplification of the technology, and does not indicate or imply that the indicated device or element necessarily has a specific orientation and is configured and operated in a specific orientation. Therefore, it cannot be understood as limiting the present application. Furthermore, terms such as "first", "second", etc. are only used to describe two or more structures or members having the same or similar structures and / or functions, and do not mean any special limitation on the order and / or importance.

[0019] Without loss of generality, in this specification, taking the application of the magnetic levitation centrifugal pump to a heart blood pump as an example, the technical solution and technical effect are introduced. Those skilled in the art will understand that the magnetic levitation centrifugal pump described in this application is a technical solution proposed based on the research of blood pumps. However, the magnetic levitation centrifugal pump in this specification is not limited to the application to heart blood pumps, and its application to other fields also falls within the protection scope of this specification.

[0020] To enable those skilled in the art to better understand the technical solution of this application, the following will refer to the accompanying drawings and specific embodiments to further elaborate on this application in more detail.

[0021] Referring to FIGS. 1 to 3, FIG. 1 is a schematic diagram of the three-dimensional structure of a magnetic levitation centrifugal pump in an embodiment of this application. FIG. 2 is a three-dimensional cross-sectional view of the magnetic levitation centrifugal pump. FIG. 3 is a schematic diagram of the cross-sectional structure of FIG. 1.

[0022] This application proposes a magnetic levitation centrifugal pump, which includes a volute casing, a static magnetic ring, and a rotor. The volute casing has a floating cavity, a medium inlet, and a medium outlet, and the rotor is located inside the floating cavity.

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

[0024] Referring further to FIGS. 4 and 5, FIG. 4 is a schematic diagram of the structure of the rotor in an embodiment of the present application. FIG. 5 is a schematic diagram of another view of the rotor shown in FIG. 4.

[0025] The rotor in the present 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 mainly provides a mounting base for mounting other components constituting the rotor and is assembled in accordance with the scroll casing. Hereinafter, the specific structure of the rotor body will be specifically introduced. The movable magnetic ring 16, the blades 13, the magnetic member 17, and the magnetic steel assembly 14 are all mounted on the rotor body. The number of blades 13 may be two or more, that is, the number of blades is at least two. Each blade is distributed along the circumferential direction. The blade 13 may be a retreating blade. In the case of a retreating blade, optimized fluid efficiency, shear force, and streamline distribution can be obtained. With the same requirements for output flow rate and pressure, the diameters of the rotor and the scroll casing can be made smaller, the requirements for the rotational speed and torque of the motor can be made lower, the volumes of the scroll casing, the rotor, and the motor can be made smaller, and miniaturization of the pump can be realized while minimizing the possibility of hemolysis and thrombus generation under the condition of the same output capacity.

[0027] Here, the number of blades 13 can be determined according to the volume of the specific pump body. Usually, it may be 3 to 7. For example, in a specific example, the number of blades is 5.

[0028] Of course, the blade 13 may be a blade of the same thickness or a straight blade, as long as the usage needs can be satisfied.

[0029] A static magnetic ring 22 is attached to the scroll casing 200. The static magnetic ring 22 is coaxially and concentrically arranged with the movable magnetic ring 16 so as to limit the radial position between the rotor 100 and the scroll casing 200. Both the static magnetic ring 22 and the movable magnetic ring 16 may include two or more annular magnets arranged along the axial direction. FIG. 3 shows a specific example in which both the static magnetic ring 22 and the movable magnetic ring 16 have three annular magnetic rings, and the movable magnetic ring 16 is concentrically arranged around the static magnetic ring 22. Naturally, the number of annular magnetic rings in the static magnetic ring 22 and the movable magnetic ring 16 is not limited to the description in this specification and may be other numbers.

[0030] During operation, the principle by which the radial position of the rotor with respect to the scroll casing 200 is limited by the movable magnetic ring 16 and the static magnetic ring 22 is as follows. The radial levitation of the rotor is realized depending on the repulsive force between the movable magnetic ring and the static magnetic ring. As described above, a set of movable magnetic rings is attached to the rotor body, and a set of static magnetic rings is attached to the scroll casing, and a permanent magnet radial levitation bearing is formed by both the movable magnetic ring and the static magnetic ring. The axial position of the static magnetic ring can be adjusted through a precision screw thread between the base 23 and the scroll casing 200. Ideally, when the position of the static magnetic ring 22 is adjusted and the rotor body levitates in the middle of the levitation cavity of the scroll casing along the axial direction, the axial positions of the static magnetic ring 22 and the movable magnetic ring 16 are exactly aligned. At this time, the radial rigidity of the permanent magnet radial levitation bearing formed by the movable magnetic ring 16 and the static magnetic ring 22 is the maximum, and the axial force is 0.

[0031] At the first end of the rotor body provided in the present application, a magnetic steel assembly 14 including N first magnetic steels 141 arranged along the circumferential direction is fixed, and the magnetic poles of all the first magnetic steels 141 are arranged alternately. Referring to FIG. 4, in the magnetic steel assembly, the first magnetic steels are formed in one turn according to the alternating arrangement of N poles and S poles. Each magnetic steel of the magnetic steel assembly 14 may be enclosed inside the rotor body. Here, in one example, the first magnetic steels 141 may be in close contact with each other to form a magnetic ring with a full pole arc. In this way, the disk motor formed with the drive coil assembly 21 attached to the spiral casing 200 can obtain high motor efficiency.

[0032] Naturally, the magnetic steel assembly 14 may further include lateral magnetic conduction magnetic steels 18. The magnetic conduction magnetic steels 18 are located between the first magnetic steels 141, that is, the same number of mutually exclusive lateral magnetic conduction magnetic steels 18 are arranged between the first magnetic steels 141 with alternately arranged magnetic poles. For example, 10 sets of first magnetic steels and magnetic conduction magnetic steels are arranged alternately to form a Halbach magnetic steel array (any even number of sets from 4 to 16 is acceptable, and 10 sets are a selectable solution). Such a magnetic steel array can exert the effect of concentrating magnetic fields. With the same volume of magnetic steel, it can improve the magnetic density between the motor air gaps, thereby further improving the motor efficiency.

[0033] Naturally, the installation of the magnetic steel assembly 14 is not limited to the method described in this specification, and other methods may be used as long as the functions described in this specification can be realized.

[0034] Correspondingly, a drive coil assembly 21 is encapsulated in a first end portion of the scroll casing 200 corresponding to the magnetic steel assembly 14 attached to the rotor. Here, the drive coil assembly 21 may include a drive coil 211 and an operating iron core 212. During operation, an electric current is passed through the drive coil 211 to generate a magnetic field, and the operating iron core 212 functions to amplify the magnetic field generated by the drive coil 211. The first magnetic steel 141, in which the magnetic poles of the magnetic steel assembly 14 attached to the rotor body are alternately arranged, generates a rotational force to drive the rotor body to rotate. 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 for controlling the axial position of the rotor body is generated by the magnetic member 17 and the magnetic levitation coil assembly 27. By adjusting the current direction of the magnetic levitation coil assembly 27, the direction of the force between the magnetic levitation coil 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 iron core 272. Here, the axial position of the rotor body can be known by a position sensor.

[0036] In this embodiment, the rotational drive and axial position control of the rotor are completely independent and are respectively located on both sides of the rotor body, and the control logic is simple. And in the present application, the complete levitation operation of the rotor can be realized by the magnetic force action between the movable magnetic ring 16 and the static magnetic ring 22. In this way, there is no mechanical contact between the rotor 100 and the scroll casing 200 (corresponding to the stator), reducing heat generation and wear, minimizing the possibility of thrombus generation and the possibility of blood cells being crushed and destroyed. The radial levitation limit of the rotor 100 can be realized depending on the movable magnetic ring and the static magnetic ring.

[0037] In this specific example, there are a first annular housing 203 and a second annular housing 204 in the inner cavity of the volute casing 200. The first annular housing 203 and the second annular housing 204 are respectively located at the first end and the second end of the volute casing. The first annular housing 203 and the volute casing enclose a first sealed cavity for enclosing the drive coil, and the second annular housing and the volute casing enclose 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. The first annular housing 203 and the second annular housing 204 are both of ceramic structure. The drive coil assembly 21 is arranged in contact with the first annular housing 203, and the magnetic levitation coil 271 is arranged in contact with the second annular housing 204.

[0038] Each annular housing may be fixed to the volute casing by adhesion or other means. The ceramic material has excellent compatibility with blood. Since the ceramic material is very hard and insulating, the wall thickness of the annular housing may be thin, and the drive coil may be in close contact with the inner wall. Thereby, the air gap between the drive coil and the first magnetic steel is greatly reduced, eddy current loss is completely eliminated, the Halbach array arrangement can be used for the first magnetic steel, the efficiency of the motor is improved, and the miniaturization of the blood pump is realized while the maximum output capacity remains unchanged. Due to the insulating property of the ceramic, the risk of leakage current from the drive coil to the blood flowing in the volute casing is minimized, and the operation of the disk motor formed by the drive coil assembly and the first magnetic steel assembly can be prevented from being interfered by an external electric field. For example, when a patient receives electroshock / electrical defibrillation / 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 pedestal 11, and the two are fixedly connected and arranged along the axial direction. Each blade is located between the annular body 12 and the pedestal 11, and there is a liquid outlet between the annular body 12 and the pedestal 11. The liquid outlet may be located between two blades. The central through hole of the annular body 12 communicates with the liquid outlet 100a. The interiors of the annular body 12 and the pedestal 11 are both filled with a magnetic steel assembly, and the movable magnetic ring 16 is enclosed inside the pedestal 11. The annular body 12 and the pedestal are both fixedly connected and arranged along the axial direction, and there is a liquid outlet between the annular body 12 and the pedestal 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 media inlet. Here, the number of the liquid outlets 100a may be plural and is uniformly arranged along the circumferential direction. The specific number can be determined according to specific products and is not limited in this specification.

[0040] Specifically, the pedestal has an annular enclosed cavity, the movable magnetic ring is fitted on the inner ring wall of the annular enclosed cavity, the magnetic member enclosed in the pedestal is located around the movable magnetic ring, and along the radial direction, the axial height of the middle region of the annular enclosed cavity is larger than the axial height of the edge region.

[0041] In this way, the occupation of the enclosed cavity for the fluid space inside the pump is minimized as much as possible, which is beneficial to the compactness of the structure. To facilitate installation, the annular enclosed cavity may be formed in the following manner. An annular groove is provided on the pedestal, and the lower cover plate 111 covers the groove 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 by using the method in which the annular groove and the upper cover plate 121 cooperate to seal.

[0042] The rotor in this application may be a centrifugal fully enclosed rotor. When the centrifugal pump operates, a large amount of blood flows into the inside of the centrifugal pump through the inflow path, is accelerated by the centrifugal blades of the rotor, and then flows out from the outflow path to inject the blood into the aorta to provide pressure and flow rate for the whole body's blood circulation. The centrifugal blades of the rotor may have a hollow structure.

[0043] In each of the above embodiments, the static magnetic ring may be attached inside the volute casing by the following method. 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 are fixedly sealed. The static magnetic ring is fixed to the base via a threaded member, and the threaded member can be a member such as a screw, a bolt, or a screw. The static magnetic ring is attached to the attachment space formed by the cover and the base. An attachment through-hole is provided at the second end of the volute casing. The attachment through-hole is coaxial with the media inlet. The thread of the base 23 is hermetically connected to the attachment 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 static magnetic ring 22 is located inside the cylinder 241. The guide cone 242 passes through the central hole of the pedestal 11 and protrudes toward the media inlet. The guide cone 242 has a smaller radial size closer to the media inlet. In this way, the fluid at the media inlet of the volute casing flows uniformly in the circumferential direction under the diversion of the guide cone and further flows uniformly between the blades.

[0044] In the above embodiment, the base and the volute casing are connected by threads, and the axial position of the base relative to the volute casing can be accurately adjusted so as to accurately cooperate with the movable magnetic ring in the rotor.

[0045] Referring to FIGS. 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 pedestal are both provided with several protrusions 1212 (only the protrusions on the outer end surface of the annular body are shown in the figure). The protrusions extend from the inner edge side to the outer edge side, and the protrusions 1212 have a predetermined included angle with respect to the radial direction. The distance between adjacent protrusions becomes smaller as it is closer to the inner edge side, and the protrusions 1212 exhibit an internal spiral structure. In this way, a hydrodynamic fluid 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 pedestal and the second annular housing. When the rotor receives a very large axial interference and one end approaches the annular housing on this side, the hydrodynamic fluid bearing can provide an additional centering restoring force, thereby improving the axial stability of the impeller.

[0046] Naturally, the closer the protrusions 1212 are to the inner edge, the lower their height. Similarly, the above technical effects can be achieved, as shown in FIG. 7. In a specific embodiment, a first auxiliary passage is formed between the outer peripheral surface and the outer end surface of the annular body and the corresponding inner wall of the volute casing. A second auxiliary passage is formed between the outer peripheral surface and the outer end surface of the annular enclosed cavity and the corresponding inner wall of the volute casing, and between the inner peripheral wall 113 of the annular enclosed cavity and the cover 24.

[0047] During operation, the rotor floats in the middle of the volute casing 200 and rotates at high speed. The blades between the annular body 12 and the pedestal 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, enters 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] Also, a very small part of the blood that enters the main flow path inside the volute casing 200 flows back through the first auxiliary passage and the second auxiliary passage respectively, returns to the inlet of the rotor body again, enters between the blades again, is accelerated, and then enters the inside of the volute casing. With the above design, all the flow paths through which the blood entering the centrifugal pump flows are one-way flows, and there are no stationary regions or reverse flow regions, thereby minimizing the possibility of thrombus formation.

[0049] Also, as described above, since the annular body and the annular housing facing the end face of the pedestal are made of ceramic material, its surface is hard and smooth. When the rotor and the annular housing come into contact unintentionally, the possibility of the surface of the annular housing being damaged is reduced. Since the motor efficiency is higher, under the same conditions, the thickness of the first magnetic steel in the rotor can be made thinner, and correspondingly, the thickness of the annular body 12 and the outer end wall (cover plate) of the pedestal 11 can also be made thinner, thereby shortening the length of the reverse flow path in the volute casing.

[0050] Also, the outer end face of the annular body and the outer end face of the pedestal both have a predetermined included angle with respect to the horizontal plane. From the outside to the inside, the distance from the outer end face to the horizontal plane increases. That is, the outer end faces of the annular body and the pedestal are concave inward. The rotor has inward-facing tapered surfaces on the upper and lower outer end faces. Therefore, the outer gap of the auxiliary passage formed between the outer end face and the inner wall of the volute casing is small, and the inner gap is large. In this way, when the blood passes through the region with a small outer gap, the shear force is relatively high, the flow velocity is fast, and the passing time is short. When passing through the region with a large inner gap, the flow velocity is relatively low and the shear force is also low, minimizing the possibility of hemolysis and thrombus formation. In this way, the gap of the auxiliary passage can be made relatively small, reducing the reverse flow loss of the centrifugal pump, improving the fluid efficiency, and making it possible to make the diameters of the rotor and the volute casing smaller under the same requirements of the output flow rate / pressure of the centrifugal pump, and reducing the requirements for the rotational speed and torque of the motor. Thereby, the volume of the volute casing / rotor is reduced, and the miniaturization of the centrifugal pump is realized under the condition of the same output capacity.

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

[0052] As described above, the magnetic levitation centrifugal pump provided in the present application has been introduced in detail. In this specification, specific individual examples are applied to describe the principles and embodiments of the present application. However, the description of the above examples is only for helping to understand the method and the core idea of the present application. It should be noted that those skilled in the art can make some improvements and modifications to the present application without departing from the principles of the present application, and these improvements and modifications are also included within the protection scope of the claims of the present application.

Claims

1. comprising a scroll casing, a permanent magnet ring, and a rotor, wherein the scroll casing has a floating cavity, a medium inlet, and a medium outlet, the rotor is located inside the floating cavity, and the permanent magnet ring is fixed to the scroll casing, the rotor includes a rotor body, a movable magnet ring positioned on the rotor body, and at least two blades, and the movable magnet ring is coaxially and concentrically arranged with the permanent magnet ring so as to limit the radial position between the rotor body and the scroll casing, a magnetic steel assembly including N first magnetic steels arranged along the circumferential direction is fixed to the rotor body, the poles of all the first magnetic steels are alternately arranged, and a magnetic member is further fixed to the rotor body, and the magnetic member includes at least one of a magnetic ring and an iron core, a drive coil assembly provided relative to the magnetic steel assembly is enclosed in the scroll casing, 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 scroll 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, characterized in that it is a magnetic levitation centrifugal pump.

2. further comprising a position sensor for detecting the axial position of the rotor body, or / and, whether adjacent first magnetic steels are in close contact, or the magnetic steel assembly further includes a lateral magnetic conduction magnetic steel located between two of the first magnetic steels, and a Halbach magnetic steel array is formed by all the magnetic conduction magnetic steels and all the first magnetic steels, characterized in that it is the magnetic levitation centrifugal pump according to Claim 1.

3. the magnetic steel assembly and the magnetic member are respectively provided at the first end and the second end of the rotor body, and the drive coil assembly and the magnetic levitation coil assembly are respectively provided at the first end and the second end of the scroll casing, characterized in that it is the magnetic levitation centrifugal pump according to Claim 1.

4. There is a first annular housing and a second annular housing inside the spiral casing. The first annular housing and the second annular housing are respectively located at the first end and the second end of the spiral casing. A first sealed cavity for enclosing the drive coil is surrounded by the first annular housing and the spiral casing. A second sealed cavity for enclosing the magnetic levitation coil assembly is surrounded by the second annular housing and the spiral casing. The levitation cavity is formed between the first annular housing and the second annular housing. Both the first annular housing and the second annular housing have a ceramic structure. The drive coil assembly is arranged in contact with the first annular housing, and the magnetic levitation coil is arranged in contact with the second annular housing. The magnetic levitation centrifugal pump according to any one of claims 1 to 3, characterized in that.

5. The rotor body includes an annular body and a pedestal, and the two are fixedly connected and arranged along the axial direction. There is a liquid outlet between the annular body and the pedestal. The central through hole of the annular body communicates with the liquid outlet. The central through hole is coaxial with the medium inlet. Each blade is located between the annular body and the pedestal. The magnetic steel assembly is enclosed inside the annular body. The movable magnetic ring and the magnetic member are enclosed inside the pedestal. The magnetic levitation centrifugal pump according to any one of claims 1 to 3, characterized in that.

6. The pedestal has an annular enclosed cavity. The movable magnetic ring is fitted on the inner ring wall of the annular enclosed cavity. The magnetic member enclosed in the pedestal is located around the movable magnetic ring. Along the radial direction, the axial height of the middle region of the annular enclosed cavity is larger than the axial height of the edge region. The magnetic levitation centrifugal pump according to claim 5, characterized in that.

7. It further includes a base and a cover, the cover has a cylinder with one end open and a guide cone connected to the other end of the cylinder, the opening of the cylinder is hermetically engageable with the base along the circumferential direction, the static magnetic ring is fixed to the base via a threaded member and is located inside the cylinder, and the base is hermetically connectable to the thread of the volute casing and is coaxial with the medium inlet, the guide cone penetrates through the central hole of the annular enclosure cavity and protrudes towards the medium inlet. The magnetic levitation centrifugal pump according to claim 6, characterized in that.

8. A first auxiliary passage is formed between the outer peripheral surface and the outer end surface of the annular body and the corresponding inner wall of the volute casing, a second auxiliary passage is formed between both the outer peripheral surface and the outer end surface of the annular enclosure cavity and the corresponding inner wall of the volute casing and between the inner peripheral wall of the annular enclosure cavity and the cover, and the outer end surfaces of the annular body and the pedestal both have a predetermined included angle with respect to the horizontal plane, and from the outside to the inside, the distance from the outer end surface to the horizontal plane increases. The magnetic levitation centrifugal pump according to claim 7, characterized in that.

9. Several protrusions are provided on both the outer end surfaces of the annular body and the pedestal, the protrusions extend from the inner edge side to the outer edge side, and the protrusions have a predetermined included angle with respect to the radial direction, and the distance between adjacent protrusions becomes smaller as it is closer to the inner edge side, or the height of the protrusions becomes lower as it is closer to the inner edge. The magnetic levitation centrifugal pump according to claim 5, characterized in that.

10. The rotor has a centrifugal type fully enclosed rotor structure, the blades are backward blades, the magnetic steel assembly and the magnetic member are respectively provided at the first end and the second end of the rotor body, and the blades are located between the magnetic steel assembly and the magnetic member. Or / and, the magnetic member includes a magnetic ring. The magnetic levitation centrifugal pump according to claim 1 or 2, characterized in that.

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