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] This application claims the priority of a Chinese patent application with an application number of 202210565532.4 and an application title of "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.

Technical Field

[0002] This application relates to the field of vibration reduction technology, and in particular, 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% to 20% of people suffer from heart failure to varying degrees. 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 (English full name: Blood Pump). Generally, the inflow pipeline of the blood pump is connected to the left ventricle or right ventricle of the human heart, and is connected to the aorta or pulmonary artery through the outflow pipeline. The pump is connected to a control driver (with a power supply device), and the blood pump is controlled by the control driver to send out 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. In view of the restrictions on the usage environment of a blood pump, on the premise of satisfying its functions, how to endow the blood pump with 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

[0004] The object of the present application is to provide a magnetic levitation centrifugal pump that is small in volume and compact.

Means for Solving the Problems

[0005] 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 and a movable magnetic ring positioned on the rotor body. 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, and the magnetic poles of all the first magnetic steels are arranged alternately. Drive coil assemblies are further enclosed at both ends of the volute casing. The two drive coil assemblies cooperate with the magnetic steel assembly to provide an axial force and a rotational force for the rotor body to move along the axial direction.

[0006] The centrifugal pump provided in the present application provides axial limits by means of magnetic steel assemblies provided at both ends of the rotor body and corresponding drive coil assemblies on the volute casing, without the need for additional coils and sensor assemblies, without additional power consumption for position control, and without the need for a sensor assembly for axial position control. Therefore, there is no electronic device in the centrifugal pump embedded in the body, and it has a stronger ability to withstand interference, higher reliability, and its performance does not degrade with the extension of the operating time. Therefore, compared with the existing technology, such axial floating technology can achieve high reliability and miniaturization of the blood pump.

[0007] Also, in the present application, the complete floating operation of the rotor is realized by the magnetic force action between the movable magnetic ring and the static magnetic ring. 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.

[0008] Optionally, magnetic steel assemblies are provided at both ends of the rotor body, the magnetic steel assemblies at both ends of the rotor body are symmetric about the central cross-section of the rotor body, the drive coil assemblies located at both ends of the volute casing are symmetric about the central cross-section of the floating cavity, and a set of disk motors are formed by the magnetic steel assemblies and the drive coil assemblies on the same side. The disk motors at both ends together provide an axial force and a rotational force that move along the axial direction of the rotor body. Or / and, 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.

[0009] Optionally, at least one end of the rotor body further encapsulates a magnetic member, and a magnetic levitation coil is encapsulated at the corresponding end of the scroll casing. When the magnetic levitation coil is energized, an axial force is generated by the magnetic levitation coil and the magnetic member. Here, the magnetic member includes at least one of an iron core or a second magnetic steel.

[0010] Optionally, both ends of the rotor body encapsulate the magnetic member, and the two magnetic members are symmetric about the central cross-section of the rotor body. Both ends of the scroll casing encapsulate the magnetic levitation coil, and the two magnetic levitation coils are symmetric with respect to the central cross-section of the levitation cavity.

[0011] Optionally, the number of the magnetic members is plural and they are uniformly arranged along the circumferential direction. The magnetic members are arranged between adjacent first magnetic steels. Or / and, the magnetic members are axially overlapped with the first magnetic steel. Or / and, the magnetic levitation coil is axially overlapped and arranged with the drive coil assembly.

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

[0013] Optionally, the rotor body includes an annular body and a pedestal, which are fixedly connected and arranged along the axial direction, and 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. There is a blade between the annular body and the pedestal to form a fully enclosed rotor structure. The annular body and the pedestal both enclose the magnetic steel assembly, and the movable magnetic ring is enclosed inside the pedestal.

[0014] Optionally, the pedestal has a first annular enclosed cavity, the movable magnetic ring is fitted on the inner ring wall of the first annular enclosed cavity, and the first iron core and the magnetic steel assembly enclosed in the pedestal are located around the movable magnetic ring. Along the radial direction, the axial height of the middle region of the first annular enclosed cavity is greater than that of the edge region.

[0015] 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. 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 first annular enclosed cavity and protrudes towards the medium inlet.

[0016] Optionally, a first auxiliary passage is formed between the outer peripheral wall and the outer end wall of the annular body and the corresponding inner wall of the volute casing. A second auxiliary passage is formed between the outer peripheral wall and the outer end wall of the first annular enclosed cavity and the corresponding inner wall of the volute casing, and between the inner peripheral wall of the first annular enclosed cavity and the cover. The outer end faces 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 face to the horizontal plane increases.

[0017] 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. Or / and, the blade is a retreat wing.

[0018] Optionally, the rotor body is an annular housing, the number of the magnetic steel assemblies is one, each of the first magnetic steels is enclosed in the inner cavity of the annular housing, each of the first magnetic steels extends from one end of the rotor body to the other end, and there are at least two groove bodies on the end surface of the annular housing facing the media inlet of the volute casing. The opening of the groove body faces the media inlet of the volute casing, the groove body is located between adjacent first magnetic steels, and the main liquid flow path of the rotor body is formed by the groove body.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Explanation of Signs

[0020] 100…rotor, 11…pedestal, 111…lower cover plate, 112…first annular enclosed cavity, 113…inner peripheral wall, 12…annular body, 121…upper cover plate, 1211…outer end face, 1212…projection, 13…blade, 14…magnetic steel assembly, 15…magnetic member, 16…rotating magnetic ring, 18…magnetic conductive magnetic steel 100’…rotor, 14…magnetic steel assembly, 141…first magnetic steel, 110…annular housing, 120…grooved body, 111’…cover plate 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…guide cone, 25…magnetic levitation coil 300…inlet pipe 400…outlet pipe 1a…first auxiliary passage, 1b…second auxiliary passage, 100a…liquid outlet

Embodiment for Carrying Out the Invention

[0021] 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 explanation of the simplification of the technology, and does not indicate or imply that the shown device or element necessarily has a specific orientation and is configured and operated in a specific orientation. Therefore, it cannot be understood as limiting 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.

[0022] Without losing generality, in this specification, the technical solutions and technical effects are introduced by taking the application of the magnetic levitation centrifugal pump to the heart blood pump as an example. 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 the heart blood pump, and its application to other fields also falls within the protection scope of this specification.

[0023] To enable those skilled in the art to better understand the technical solutions of this application, the following will further describe this application in more detail with reference to the accompanying drawings and specific embodiments.

[0024] Referring to FIGS. 1 to 3, FIG. 1 is a schematic diagram of the three-dimensional structure of the 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.

[0025] This application proposes a magnetic levitation centrifugal pump, which includes a volute casing 200, a static magnetic ring 22, and a rotor 100. The volute casing 200 has a floating cavity, a medium inlet, and a medium outlet, and the rotor 100 is located inside the floating cavity.

[0026] Here, the volute casing 200 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 in the first volute casing, and the medium outlet may be formed by the corresponding structures on the first volute casing and the second volute casing together enclosing it. An inlet pipe is attached to the medium inlet, and an outlet pipe is attached to the medium outlet. The first volute casing, the second volute casing, the inlet pipe, and the outlet pipe may all be made of titanium alloy material.

[0027] Referring 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.

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

[0029] Here, the rotor body mainly provides a mounting base for mounting other components that make up 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, the blades, and the magnetic steel assembly are all mounted on the rotor body. The number of blades 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 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.

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

[0031] Of course, the blades may be blades of the same thickness or straight blades, as long as the usage needs can be met.

[0032] A static magnetic ring 22 is attached to the scroll casing. The static magnetic ring is coaxially and concentrically arranged with the movable magnetic ring 16 so as to limit the radial position between the rotor and the scroll casing. Both the static magnetic ring and the movable magnetic ring 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 and the movable magnetic ring have three annular magnetic rings, and the movable magnetic ring is concentrically arranged around the static magnetic ring. Of course, the number of annular magnetic rings in the static magnetic ring and the movable magnetic ring is not limited to the description in this specification and may be other numbers. 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. A permanent magnet radial magnetic bearing is constituted 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 thread between the base and the scroll casing, and the radial levitation of the rotor is realized depending on the repulsive force between the movable magnetic ring and the static magnetic ring.

[0033] Both ends of the rotor body provided in the present application are fixed with a magnetic steel assembly 14 including N first magnetic steels 141 arranged along the circumferential direction. The poles of all the first magnetic steels are alternately arranged. Referring to FIG. 4, the first magnetic steels in the magnetic steel assembly are formed in a circle according to the alternating arrangement of N poles and S poles. Each magnetic steel in the magnetic steel assembly may be enclosed inside the rotor body. Here, in one example, the first magnetic steels may be in close contact with each other to form a full-pole arc magnetic ring. In this way, a disk motor formed with a drive coil assembly attached to the scroll casing can obtain high motor efficiency.

[0034] Of course, the magnetic steel assembly may further include a lateral magnetic conduction magnetic steel 18, which is located between the first magnetic steels, that is, the same number of mutually exclusive lateral magnetic conduction magnetic steels are arranged between the first magnetic steels with alternating magnetic poles. For example, 10 sets of the first magnetic steels and magnetic conduction magnetic steels are arranged alternately to form a Halbach magnetic steel array (it may be an even number of sets from 4 to 16, and 10 sets are a selectable solution). Such a magnetic steel array can exert the effect of concentrating magnetism, and with the same volume of magnetic steel, it can improve the magnetic density between the motor air gaps, thereby further improving the motor efficiency.

[0035] Of course, the installation of the magnetic steel assembly 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.

[0036] Correspondingly, the ends of the spiral casing corresponding to the magnetic steel assembly attached to the rotor are both enclosed with a drive coil assembly 21. Here, the drive coil assembly may include a drive coil 211 and an operating iron core 212. The drive coil assemblies at both ends may be provided symmetrically about the central cross-section of the floating cavity, and of course, they may also be provided asymmetrically. During operation, an alternating current is passed through the drive coil to generate a magnetic field, and the operating iron core plays an amplifying function with respect to the magnetic field generated by the drive coil. The first magnetic steels with alternating magnetic poles of each magnetic pole of the magnetic steel assembly attached to the rotor body generate an axial force. The controller detects the difference in the electromotive force or inductance fed back by the upper and lower drive coils to confirm the difference in the distance from the rotor to the position of the upper and lower drive coils, and thereby adjusts the drive parameters of the upper and lower drive coils (not limited to current, voltage, duty cycle, etc.) to change the magnitude of the axial force generated by the drive coil on the first magnetic steel in the rotor, thereby controlling the axial position of the rotor so that the rotor body always floats to the central position where the distances to the upper and lower end walls of the spiral casing are the same under the action of the axial electromagnetic force of the motor and operates.

[0037] Such a levitation method does not require additional coils and sensor assemblies, so the volume and weight can be significantly reduced. The control of the rotor body position is achieved by adjusting the current of the upper and lower motors, and no additional power consumption occurs due to position control. Since axial position control does not require a sensor assembly, there is no electronic device in the centrifugal pump embedded in the body, and it has a stronger ability to withstand interference, higher reliability, and its performance does not decrease with the extension of the operating time. Therefore, compared with the existing technology, such axial levitation technology can achieve high reliability and miniaturization of the blood pump.

[0038] In addition, in the present application, the complete levitation operation of the rotor is realized by the magnetic force action between the movable magnetic ring and the static magnetic ring. 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 levitation limit of the rotor can be realized depending on the movable magnetic ring and the static magnetic ring.

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

[0040] To simplify the control logic, a magnetic member 15 is further encapsulated at at least one end of the rotor body in the present application. The accompanying drawings show a specific example in which magnetic members are encapsulated at 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 encapsulated at the corresponding end of the volute casing. When a direct current is passed through the magnetic levitation coil, an axial force is generated by the magnetic levitation coil and the magnetic member.

[0041] If magnetic members are encapsulated at both ends of the rotor body, the two magnetic members are symmetric with respect to the central cross-section of the rotor body. If magnetic levitation coils are encapsulated at both ends of the volute casing, the two magnetic levitation coils are symmetric with respect to the central cross-section of the levitation cavity, and the symmetric installation makes it easier to control.

[0042] In this way, by controlling the current of the drive coil, the rotation of the rotor body is realized, and by controlling the current of the magnetic levitation coil, the adjustment of the axial position of the rotor body is realized.

[0043] In a specific example, the number of magnetic members may be plural and they are uniformly arranged along the axial direction. The magnetic members are arranged between adjacent first magnetic steels. Here, FIG. 9 shows a specific embodiment in which the magnetic members and the 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 steels can also be arranged by being overlapped along the axial direction.

[0045] In this specific example, there is an annular housing in the inner cavity of the volute casing. The annular housing and the volute casing enclose a sealed cavity. The drive coil assembly is located in the sealed cavity. 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 two annular housings at both ends. In this specification, the annular housing attached to the first volute casing is defined as the first annular housing 203, and the annular housing attached to the second volute casing is defined as the second annular housing 204. That is, the rotor body can reciprocate and move axially between the two annular housings. Here, the annular housing has a ceramic structure.

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

[0047] The ceramic material has excellent compatibility with blood. Since the ceramic material is very hard and insulating, the wall thickness of the annular housing can be thin, and the drive coil can be in close contact with the inner wall. Thereby, the air gap between the drive coil and the first magnetic steel is significantly reduced, eddy current loss is completely eliminated, and the Halbach array arrangement can be used for the first magnetic steel, improving the efficiency of the motor and realizing the miniaturization of the blood pump while the maximum output capacity remains unchanged. Due to the insulating properties of the ceramic, the risk of leakage current generated from the drive coil to the blood flowing in the scroll 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 an electric shock / electrical defibrillation / electrotome cutting treatment, the magnetic levitation centrifugal pump can still operate normally.

[0048] Referring to FIGS. 6 and 7, FIG. 6 is a schematic diagram of a rotor in another embodiment of the present application. FIG. 7 is a schematic diagram of a rotor in still another embodiment of the present application.

[0049] 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. There is a liquid outlet 100a between the annular body 12 and the pedestal 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 pedestal 11. The interiors of the annular body 12 and the pedestal 11 are both enclosed with a magnetic steel assembly, and the movable magnetic ring is enclosed inside the pedestal 11. Both the annular body 12 and the pedestal 11 are 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. The central through hole of the annular body 12 is coaxial with the media inlet. The number of liquid outlets 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.

[0050] Specifically, the pedestal 11 has a first annular enclosed cavity 111, the movable magnetic ring is fitted on the inner annular wall of the first annular enclosed cavity, and the first iron core and the magnetic steel assembly enclosed in the pedestal 11 are located around the movable magnetic ring. Along the radial direction, the axial height of the intermediate region of the first annular enclosed cavity is greater than the axial height of the edge region.

[0051] In this way, the occupation of the enclosed cavity with respect to the fluid space inside the pump is minimized as much as possible, which is advantageous for the compactness of the structure.

[0052] To facilitate the installation, the first annular enclosed cavity may be formed in the following manner: an annular groove is provided in the pedestal 11, and the lower cover plate 111 covers the groove opening of the annular groove to form a sealed cavity. Based on the same principle, the sealed cavity for attaching the magnetic steel assembly to the annular body 12 can also be formed by using a method in which the annular groove and the upper cover plate 121 cooperate to seal.

[0053] The rotor in the present application may be a centrifugal fully enclosed rotor. When the centrifugal pump operates, a large amount of blood flows into 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, providing pressure and flow rate for the systemic blood circulation. The centrifugal blades of the rotor may have a hollow structure.

[0054] Referring to FIGS. 10 and 11, in another specific embodiment, the rotor body 100' includes an annular housing 110. The number of the 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 of the rotor body to the other end. The N pole and the S pole of the first magnetic steel 141 are respectively close to both ends of the annular housing 110. On the end face of the medium inlet towards the volute casing of the annular housing 110, there are at least two groove bodies 120. The openings of the groove bodies 120 face the medium inlet of the volute casing. The groove bodies 120 are located between adjacent first magnetic steels. The groove bodies 120 form the main liquid flow path of the rotor body. That is, in this embodiment, the medium entering from the medium inlet of the volute casing flows out from the groove bodies 120 and flows to the medium outlet. 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 that in the above embodiment.

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

[0056] In one example, the magnetic levitation centrifugal pump further includes a base and a cover engaged with the base. The cover 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 or a bolt or a screw. The static magnetic ring is mounted in the mounting space formed by the cover and the base. A mounting through hole is provided at the second end of the volute casing. The mounting through hole is coaxial with the medium inlet. The thread of the base is hermetically 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 static magnetic ring is located inside the cylinder. The guide cone penetrates through the central hole of the pedestal 11 and protrudes towards the medium inlet. The guide cone has a smaller radial size closer to the medium inlet. In this way, the fluid at the medium 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.

[0057] In the above embodiments, the base 23 and the volute casing are connected by a thread, and the axial position of the base with respect to the volute casing can be accurately adjusted so as to accurately cooperate with the movable magnetic ring in the rotor.

[0058] Referring to FIG. 9, in each of the above embodiments, several protrusions 1212 are provided on both the outer end surface 1211 of the annular body 12 and the outer end surface (not numbered) of the pedestal 11. 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, and the protrusions exhibit an internal spiral structure. In this way, a hydrodynamic fluid 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 pedestal 11 and the lower annular housing. When the rotor receives a very large interference in the axial direction and one end approaches the annular housing on this side, the hydrodynamic fluid bearing can provide an additional restoring force toward the center, thereby improving the stability of the impeller along the axial direction.

[0059] Referring to FIG. 10, naturally, the closer the protrusion is to the inner edge, the lower its height, and similarly, the above technical effects can be achieved.

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

[0061] During operation, the rotor floats in the middle of the volute casing and rotates at a high speed. The blades between the annular body 12 and the pedestal 11 and the inner wall of the volute casing form the main flow path of the pump. Blood flows in from the medium inlet, enters the main flow path between the blades through the central through hole of the annular body 12, 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.

[0062] Also, a very small part of the blood that enters the main flow path inside the volute casing flows back to the inlet of the rotor body through the first auxiliary passage 1a and the second auxiliary passage 1b respectively, enters between the blades again and 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 unidirectional flows, and there are no stationary regions or reverse flow regions, thereby minimizing the possibility of thrombus formation.

[0063] Also, as described above, since the annular housing facing the end face of the pedestal 11 of the annular body 12 is made of a 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. Because 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.

[0064] Also, the outer end face of the annular body 12 and the outer end face of the pedestal 11 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 12 and the pedestal 11 are concave inward, and 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 generation. 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 enabling the diameters of the rotor and the volute casing to be made smaller under the same requirements of 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.

[0065] The magnetic levitation centrifugal pump provided in the present application has been introduced in detail above. In this specification, specific individual examples are applied to describe the principle and embodiments of the present application. However, the description of the above examples is only for helping to understand the method of the present application and its core idea. It should be noted that those skilled in the art can make several improvements and modifications to the present application without departing from the principle 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. including 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, and the static magnetic ring is fixed to the volute casing, the rotor includes a rotor body and a movable magnetic ring positioned on the rotor body, and 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 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 ends of the volute casing, and the two drive coil assemblies cooperate with the magnetic steel assembly to provide an axial force and a rotational force for the rotor body to move along the axial direction, A magnetic levitation centrifugal pump characterized by the above.

2. Both ends of the rotor body are provided with the magnetic steel assembly, the magnetic steel assemblies at both ends of the rotor body are symmetric about the central cross-section of the rotor body, the drive coil assemblies located at both ends of the volute casing are symmetric about the central cross-section of the floating cavity, and a set of disk motors are formed by the magnetic steel assembly and the drive coil assembly on the same side. The disk motors at both ends together provide an axial force and a rotational force for the rotor body to move along the axial direction, Or / and, 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, The magnetic levitation centrifugal pump according to claim 1, characterized by the above.

3. At least one end of the rotor body is further encapsulated with a magnetic member, and a magnetic levitation coil is encapsulated at a corresponding end of the volute casing. When the magnetic levitation coil is energized, an axial force is generated by the magnetic levitation coil and the magnetic member. Here, the magnetic member includes at least one of a core or a second magnetic steel. The magnetic levitation centrifugal pump according to claim 1 or 2, characterized in that.

4. Both ends of the rotor body are encapsulated with the magnetic member, and the two magnetic members are symmetric with respect to the central cross-section of the rotor body. Both ends of the volute casing are encapsulated with the magnetic levitation coil, and the two magnetic levitation coils are symmetric with respect to the central cross-section of the levitation cavity. The magnetic levitation centrifugal pump according to claim 3, characterized in that.

5. The number of the magnetic members is plural and they are uniformly arranged along the circumferential direction. The magnetic members are arranged between adjacent first magnetic steels. Or / and, the magnetic members are overlapped with the first magnetic steel along the axial direction. Or / and, the magnetic levitation coil is arranged to overlap with the drive coil assembly along the axial direction. The magnetic levitation centrifugal pump according to claim 3, characterized in that.

6. There is an annular housing in the inner cavity of the volute casing. A sealed cavity is surrounded by the annular housing and the volute casing. The drive coil assembly is located in the sealed cavity. The levitation cavity is formed between two annular housings located at both ends. The annular housing has a ceramic structure, and the drive coil assembly is arranged in contact with the annular housing. The magnetic levitation centrifugal pump according to claim 1 or 2, characterized in that.

7. The rotor body includes an annular body and a pedestal, which are fixedly connected and arranged along the axial direction, and 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 media inlet. There are blades between the annular body and the pedestal to form a fully enclosed rotor structure. The inside of the annular body and the pedestal are both filled with the magnetic steel assembly, and the movable magnetic ring is enclosed inside the pedestal. The magnetic levitation centrifugal pump according to claim 2, characterized in that.

8. The pedestal has a first annular enclosed cavity. The movable magnetic ring is fitted on the inner ring wall of the first annular enclosed cavity. The first iron core and the magnetic steel assembly enclosed in the pedestal are located around the movable magnetic ring. Along the radial direction, the axial height of the middle region of the first annular enclosed cavity is larger than the axial height of the edge region. The magnetic levitation centrifugal pump according to claim 7, characterized in that.

9. 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 media inlet. The guide cone penetrates the central hole of the first annular enclosed cavity and protrudes towards the media inlet. The magnetic levitation centrifugal pump according to claim 8, characterized in that.

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

11. Several protrusions are provided on the outer end faces of both 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 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. Or / and, the blade is a retreating blade. The magnetic levitation centrifugal pump according to claim 7, characterized in that.

12. The rotor body is an annular housing, the number of the magnetic steel assemblies is one, each of the first magnetic steels is enclosed in the inner cavity of the annular housing, each of the first magnetic steels extends from one end to the other end of the rotor body, and there are at least two groove bodies on the end face of the annular housing facing the medium inlet of the volute casing. The openings of the groove bodies face the medium inlet of the volute casing, the groove bodies are located between adjacent first magnetic steels, and the main liquid flow path of the rotor body is formed by the groove bodies. The magnetic levitation centrifugal pump according to claim 1, characterized in that.

Images