CN112206409B

CN112206409B - Magnetic suspension mixed flow heart pump

Info

Publication number: CN112206409B
Application number: CN202011249353.7A
Authority: CN
Inventors: 李东海; 屈一飞; 张松; 李剑锋; 满佳
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2020-11-10
Filing date: 2020-11-10
Publication date: 2021-11-30
Anticipated expiration: 2040-11-10
Also published as: CN112206409A

Abstract

The invention relates to a magnetic suspension mixed flow heart pump, which comprises a pump body consisting of an inlet part and a volute part, wherein the pump body is provided with a cavity, a rotor capable of rotating is arranged in the cavity, the peripheral surface of the rotor is provided with an axial flow blade and a centrifugal blade, the axial flow blade is positioned in the cavity of the inlet part, the centrifugal blade is positioned in the cavity of the volute part, the volute part is provided with a flow channel communicated with the cavity and the outer space of the volute part, the tangential plane of the inflow end of the centrifugal blade and the axis of the rotor are arranged in an acute angle, and the tangential plane of the outflow end of the centrifugal blade and the axis of the rotor are arranged in parallel, so that the centrifugal blade can gradually convert the flow of blood from the direction of the axis of the rotor into the flow of the radial direction of the rotor.

Description

Magnetic suspension mixed flow heart pump

Technical Field

The invention relates to the technical field of medical instruments, in particular to a magnetic suspension mixed flow heart pump.

Background

The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.

Cardiovascular disease is the leading cause of the highest worldwide morbidity and mortality. Heart failure is the ultimate outcome of all heart diseases, and there are two main therapeutic approaches to end-and mid-stage heart failure: heart transplantation and artificial heart pumps. Due to the serious shortage of heart transplant donors, artificial heart pumps have become the main treatment means for patients with heart failure.

At present, two types of artificial heart pumps which are widely researched and applied are an axial flow pump and a centrifugal pump. The axial flow pump has the advantages of large flow and small volume; the centrifugal pump has the advantages of large lift and stable magnetic suspension. The inventor finds that the existing implanted artificial heart pump has the following disadvantages: 1) the existing axial-flow pump is mainly of a mechanical bearing support type structure, and the bearing has the problems of heating, lubrication, sealing, abrasion and the like, so that thrombosis is easily caused; 2) when the axial flow pump operates, the required rotating speed is too high, high shear stress can be generated, and blood cells are easily damaged to cause severe hemolysis; 3) compared with an axial flow pump, the centrifugal pump is large in size and is inconvenient to implant into a patient with a small body size; 4) the centrifugal pump has a large speed gradient and is easy to damage each component of blood.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a magnetic suspension mixed flow heart pump which integrates the characteristics and advantages of an axial flow pump and a centrifugal pump and better meets the clinical application requirements of heart failure patients.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, an embodiment of the present invention provides a magnetic suspension mixed flow heart pump, including a pump body including an inlet portion and a volute portion, the pump body having a cavity, a rotor being disposed in the cavity, an axial flow vane and a centrifugal vane being disposed on an outer circumferential surface of the rotor, the axial flow vane being disposed in the cavity of the inlet portion, the centrifugal vane being disposed in the cavity of the volute portion, the volute portion having a flow channel communicating with the cavity and an outer space of the volute portion, a tangential plane of an inflow end of the centrifugal vane being disposed at an acute angle to an axis of the rotor, and a tangential plane of an outflow end being disposed parallel to the axis of the rotor, so that the centrifugal vane can gradually transition blood from flowing along the axis of the rotor to flowing along a radial direction of the rotor and enter the flow channel.

Furthermore, a permanent magnet is arranged on the part of the rotor, which is positioned in the volute part, a stator is arranged on one side of the volute part, the stator is wound with a suspension winding and a torque winding, and after the stator is electrified, the permanent magnet can generate suspension force parallel to the axis direction of the inlet part and torque rotating around the axis of the inlet part to the rotor.

Furthermore, the blood inlet end of the inlet part is provided with a plurality of front guide vanes which are uniformly arranged on the inner side surface of the inlet part along the circumference and have a set gap with the outer peripheral surface of the rotor.

Furthermore, a plurality of first permanent magnet rings are arranged inside the pump body inlet part along the axis direction of the inlet part, and a second permanent magnet ring is arranged on the part of the rotor in the inlet part.

Furthermore, the flow channel adopts a spiral flow channel with the axial line on the plane vertical to the axial direction of the inlet part, and comprises an annular first flow channel part communicated with the inner cavity of the volute part and a second flow channel part communicated with the first flow channel part in a tangent mode, one end of the second flow channel part is communicated with the first flow channel part, and the other end of the second flow channel part is communicated with the outer space of the volute part.

Furthermore, a reserved gap of 0.1-1mm is formed between the outer side face of the rotor in the volute part and the inner side face of the cavity in the volute part.

Furthermore, a motor base is arranged on one side of the volute part and fixedly connected with the volute part, the stator is fixed in the motor base, a suspension winding and a torque winding are wound on stator teeth of the stator, and both the suspension winding and the torque winding can be connected with a power supply.

Furthermore, the included angle between the tangential plane of the blood inflow end of the axial flow blade and the plane vertical to the axis of the rotor is 15-45 degrees, and the included angle between the tangential plane of the blood outflow end and the plane vertical to the axis of the rotor is 45-80 degrees.

Furthermore, the included angle between the tangential plane of the blood inflow end of the centrifugal blade and the radial direction of the rotor is 10-30 degrees, and the included angle between the tangential plane of the blood outflow end and the radial direction of the rotor is 20-40 degrees.

Furthermore, the axial flow blades and the centrifugal blades are arranged at the connecting positions in a transition or separation mode by adopting round sliding surfaces.

The invention has the beneficial effects that:

1. according to the heart pump, the rotor is provided with the axial flow blades and the centrifugal blades, and the axial flow blades and the centrifugal blades share the pressure difference target and the flow demand of hydraulic performance, so that compared with a centrifugal pump with the existing structure, the requirement on the hydraulic performance of a design point is practically reduced, the overall size is reduced, the whole device is convenient for implantation of patients with small sizes, such as women, children and the like, and the surgical wound is smaller; compared with an axial flow pump, the rotary speed required by the axial flow pump during working is greatly reduced, the problems of heating, lubrication, abrasion and the like at the bearing support position can be avoided, the occurrence of high shear stress is avoided, and hemolysis and thrombosis related complications caused by blood damage are effectively reduced.

2. According to the heart pump, the rotor is provided with the axial flow blades and the centrifugal blades, the tangential plane of the inflow end of each centrifugal blade and the axis of the rotor are arranged in an acute angle, and the tangential plane of the outflow end of each centrifugal blade and the axis of the rotor are arranged in parallel, so that the centrifugal blades can enable blood to gradually transit from flowing along the axis direction of the rotor to flowing along the radial direction of the rotor and enter a flow channel, the flowing direction of the blood is enabled to be smoothly transited, and the occurrence of high-speed gradient in a flow field is avoided; blood flows more regularly in the pump orderly, and each subassembly and the violent collision of blood in the at utmost has reduced the pump, has reduced the impeller of high-speed operation and to the negative effects between each component of blood, effectively reduces the blood damage that blood streamline disorder caused, has avoided the appearance of serious complications such as hemolysis and thrombus.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.

FIG. 1 is a sectional view showing an internal structure of embodiment 1 of the present invention;

FIG. 2 is a schematic external view of embodiment 1 of the present invention;

FIG. 3 is a schematic view showing the assembly of a rotor with axial flow blades and centrifugal blades according to embodiment 1 of the present invention;

FIG. 4 is a schematic illustration of the blood flow during operation of example 1 of the present invention;

FIG. 5 is a schematic view showing the assembly of a rotor with axial flow blades and centrifugal blades according to embodiment 2 of the present invention;

the rotor comprises an inlet part 1, an upper worm casing part 2, a lower worm casing part 3, a first flow passage part 4, a second flow passage part 5, a first rotor part 6, a second rotor part 7, an axial flow blade 8, a centrifugal blade 9, a front flow guiding blade 10, a conical structure 11, a first permanent magnet ring 12, a second permanent magnet ring 13, a motor base 14, a stator 15 and a permanent magnet 16.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

For convenience of description, the words "up", "down", "left" and "right" in the present invention, if any, merely indicate correspondence with up, down, left and right directions of the drawings themselves, and do not limit the structure, but merely facilitate the description of the invention and simplify the description, rather than indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.

As described in the background art, the axial flow pump used for the heart pump at present is easy to cause thrombosis and hemolysis, the centrifugal pump is large in size and easy to damage blood components, and the magnetic suspension mixed flow heart pump is provided for solving the problems.

In a typical embodiment of the present application, as shown in fig. 1-4, a magnetic suspension mixed flow heart pump includes a pump body, the pump body is composed of an upper pump body and a lower pump body, which are fastened and fixedly connected, the pump body includes an inlet portion 1 and a volute portion, the upper pump body includes an inlet portion and an upper volute portion 2, which are coaxially and mutually perpendicular integrally connected, the lower pump body is a lower volute portion 3, the upper volute portion and the lower volute portion are fastened and fixedly formed into the volute portion, the inlet portion and the volute portion are coaxially and vertically arranged, and the diameter of the volute portion is greater than that of the inlet portion.

The volute body is characterized in that a cavity is arranged in the pump body, the cavity comprises a first cavity arranged at the inlet portion and a second cavity arranged at the volute portion, the first cavity is communicated with the second cavity, a flow channel is arranged on the volute portion, the plane where the axis of the flow channel is located is perpendicular to the axis of the inlet portion, the flow channel in the embodiment adopts a spiral flow channel and comprises a first flow channel portion 4 and a second flow channel portion 5, the first flow channel portion is annular and is arranged along the edge of the inner cavity of the volute portion and communicated with the inner cavity of the volute portion, the second flow channel portion is communicated with the first flow channel portion in a tangent mode, and blood entering the volute portion can enter the first flow channel portion and the second flow channel portion in sequence and flows out of the volute portion through the second flow channel portion.

The pump body is internally provided with a rotor, the rotor comprises a first rotor part 6 positioned in a cavity of an inlet part and a second rotor part 7 positioned in a cavity of a volute part, the first rotor part and the second rotor part are coaxially arranged with the inlet part and the volute part, the first rotor part is positioned at the central position of the inlet part, the second rotor part is positioned at the central position of the volute part, 3-5 axial flow blades 8 are arranged on the outer peripheral surface of the first rotor part, the axial flow blades are 10-25mm in length, the axial flow blades are 1-2mm in thickness, the second rotor part comprises a cylindrical part and a curved surface part, two ends of the curved surface part are respectively connected with the cylindrical part and the first rotor part, the cylindrical part is of a cylindrical structure, and the curved surface part comprises an upper plane, a lower plane and a side surface arranged between the upper plane and the lower plane, the side surface is a curved surface which is sunken towards the axial direction, 3-6 centrifugal blades 9 are fixed on the peripheral surface of the curved surface part, the outlet width of each centrifugal blade is 3-6mm, and the thickness of each centrifugal blade is 1-2 mm.

In this embodiment, one end of the inlet part is connected with the volute part, the other end of the inlet part serves as a blood inflow end, an included angle between a tangential plane of the blood inflow end of the axial flow blade and a plane perpendicular to the axis of the rotor is 15-45 degrees, an included angle between a tangential plane of the blood outflow end of the axial flow blade and a plane perpendicular to the axis of the rotor is 45-80 degrees, an included angle between a tangential plane of the blood inflow end of the centrifugal blade and the radial direction of the rotor is 10-30 degrees, and an included angle between a tangential plane of the blood outflow end of the centrifugal blade and the radial direction of the rotor is 20-40 degrees.

The centrifugal blade adopts semi-open centrifugal blade, and the tangential plane of centrifugal blade's blood inflow end is the acute angle setting of setting for with the rotor axis, and the tangential plane of blood outflow end and rotor axis parallel arrangement to make centrifugal blade can be with blood by the flow gradual transition along rotor axis direction for the flow along rotor radial direction, and get into in the runner.

The end part of the blood inflow end of the inlet part is also provided with 3-5 front flow guide blades 10 which are fixedly connected with the inner side surface of the inlet part and are uniformly distributed along the circumference. The inner side surface of the front guide vane and the outer peripheral surface of the first rotor part have a gap with a set distance so as to prevent the front guide vane from influencing the rotation of the rotor.

One end of the first rotor part of the rotor is connected with the second rotor part, and the other end of the first rotor part of the rotor adopts a conical structure 11, so that a certain flow guiding effect is realized on blood.

A gap of 0.1-1mm is formed between the second rotor part and the inner side surface of the cavity of the lower pump body, so that the rotor can smoothly and stably rotate, and collision and friction between the rotor and the pump body are avoided.

The axial flow blades and the centrifugal blades are arranged at the end parts close to each other at a set angle and a set distance in a separated mode, the separation angle and the separation distance are selected according to the inlet and outlet angles of the blades, the streamline direction and the wall surface shear stress distribution state, and the optimal value is selected comprehensively to reduce the damage of the impeller to blood to the maximum degree.

In the embodiment, the axial flow blades and the centrifugal blades of the rotor share the pressure difference target and the flow demand of hydraulic performance, compared with the centrifugal pump with the existing structure, the requirement of hydraulic performance of a design point is practically reduced, the overall size is reduced, the whole equipment is convenient for patients with small sizes, such as women, children and the like, to implant, the operation wound is smaller, compared with the axial flow pump, the rotating speed required during working is greatly reduced, the occurrence of high shear stress is avoided, and hemolysis and thrombosis related complications caused by blood damage are effectively reduced.

In this embodiment, the rotor drives axial flow blade and centrifugal blade and is synchronous rotation, and blood flows in from the blood inflow end of entering part, through the water conservancy diversion effect of preceding flowing vane piece, flow direction axial flow blade, along entering part axial direction motion under axial flow blade's effect, gets into volute portion, under centrifugal blade's effect, will follow the blood of entering part axial direction motion and progressively convert into along entering part radial direction motion for blood gets into the runner, then flows out through second runner portion. In the blood flowing process, the blood flow is gradually and smoothly transited through the axial flow blades and the centrifugal blades, so that the occurrence of high-speed gradient in a flow field is avoided; blood flows more regularly in the pump orderly, and each subassembly and the violent collision of blood in the at utmost has reduced the pump, has reduced the impeller of high-speed operation and to the negative effects between each component of blood, effectively reduces the blood damage that blood streamline disorder caused, has avoided the appearance of serious complications such as hemolysis and thrombus.

In this embodiment, the pump body inlet portion is internally embedded and fixed with two first permanent magnet rings 12 distributed along the axial direction of the inlet portion, the first rotor portion is internally provided with a strip-shaped second permanent magnet ring 13, and the rotor can be radially suspended and supported by the interaction of the first permanent magnet ring and the second permanent magnet ring, so that the rotor is limited to radially move and incline along the inlet portion, and a more ideal radial stable supporting effect is realized.

An inlet part is fixed at one end of the volute part, the shell wall at the other end of the volute part is fixedly connected with a motor base 14, a stator 15 is fixed in the motor base and provided with stator teeth, a suspension winding and a torque winding are wound on the stator teeth and can be connected with a power supply, and current is introduced into the suspension winding and the torque winding from the power supply. The stator, the rotor, the suspension winding and the torque winding jointly form the bearingless brushless direct current motor.

The inside permanent magnet 16 that is provided with four along circumference evenly distributed and for the arc structure of second rotor portion, after the suspension winding circular telegram, can produce the suspension power along entering portion axis direction and towards blood inflow end direction to the rotor through the permanent magnet, can produce the effort of keeping away from blood inflow end direction to the rotor after the torque winding circular telegram, this effort is balanced with the suspension power after, can make second rotor portion bottom surface and lower pump body bottom surface have 1-2 mm's clearance, the collision and the friction of rotor with the pump body have been avoided, can also produce the torque to the rotor after the torque winding circular telegram, drive the rotor and rotate.

The rotor is axially suspended and driven under the action of a magnetic field generated by the stator winding, and meanwhile, the disturbance of inlet and outlet pressure difference generated by blood flow to the rotor is avoided.

Through setting up permanent magnet, stator and winding, synthesize the magnetic suspension control strategy of axial-flow pump and centrifugal pump, the space utilizes more rationally, under the prerequisite of guaranteeing to operate reliably for the heart pump overall structure is compacter, has effectively fused the advantage characteristic of axial-flow pump and centrifugal pump, can be applied to the patient that the size is littleer.

Example 2:

the embodiment discloses a magnetic suspension mixed flow heart pump, as shown in fig. 5, which is different from embodiment 1 only in that the number of centrifugal blades and axial flow blades is equal, the corresponding angles and thicknesses are the same, the ends are connected with each other, and round and smooth surface transition is utilized, according to simulation results, the streamline is regular and ordered, no speed abrupt change region exists, and no interference and fluctuation which can cause damage to each component in blood exist.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.

Claims

1. A magnetic suspension mixed flow heart pump is characterized by comprising a pump body consisting of an inlet part and a volute part, wherein the pump body is provided with a cavity, a rotor is arranged in the cavity, axial flow blades and centrifugal blades are arranged on the peripheral surface of the rotor, the axial flow blades are positioned in the cavity of the inlet part, the centrifugal blades are positioned in the cavity of the volute part, a flow channel communicated with the cavity and the outer space of the volute part is arranged on the volute part, a tangential plane of an inflow end of each centrifugal blade is arranged at an acute angle with the axis of the rotor, a tangential plane of an outflow end of each centrifugal blade is arranged in parallel with the axis of the rotor, so that the centrifugal blades can gradually transition blood from the flow along the axis direction of the rotor to the flow along the radial direction of the rotor, an included angle between the tangential plane of a blood inflow end of each axial flow blade and the plane vertical to the axis of the rotor is 15-45 degrees, an included angle between the tangential plane of a blood outflow end of the blood and the plane vertical to the axis of the rotor is 45-80 degrees, the included angle between the tangential plane of the blood inflow end of the centrifugal blade and the radial direction of the rotor is 10-30 degrees, and the included angle between the tangential plane of the blood outflow end and the radial direction of the rotor is 20-40 degrees;

the rotor comprises a cylindrical part, a permanent magnet is arranged in the cylindrical part, a stator is arranged on one side of the volute part, the stator is wound with a suspension winding and a torque winding, and after the stator is electrified, the permanent magnet can generate suspension force parallel to the axis direction of the inlet part and torque rotating around the axis of the inlet part to the rotor.

2. A magnetic levitation mixed flow cardiac pump as claimed in claim 1, wherein the blood inlet end of the inlet portion is provided with a plurality of front guide vanes circumferentially uniformly disposed on the inner side of the inlet portion with a set gap from the outer peripheral surface of the rotor.

3. A magnetic suspension mixed flow heart pump as claimed in claim 1, wherein the pump body inlet portion is provided with a plurality of first permanent magnet rings inside along the axis of the inlet portion, and the rotor portion inside the inlet portion is provided with a second permanent magnet ring.

4. A magnetic suspension mixed flow cardiac pump as claimed in claim 1, wherein the flow channel is a spiral flow channel whose axis is perpendicular to the axial direction of the inlet portion, and includes a first annular flow channel portion communicating with the inner cavity of the volute portion and a second flow channel portion tangentially communicating with the first flow channel portion, and one end of the second flow channel portion communicates with the first flow channel portion, and the other end communicates with the outer space of the volute portion.

5. A magnetic suspension mixed flow heart pump as claimed in claim 1, wherein a clearance of 0.1-1mm is provided between the outer side of the rotor in the volute section and the inner side of the cavity in the volute section.

6. A magnetic suspension mixed flow heart pump as claimed in claim 1, wherein a motor base is provided at one side of the volute portion, the motor base is fixedly connected with the volute portion, the stator is fixed in the motor base, the stator teeth of the stator are wound with the suspension winding and the torque winding, and both the suspension winding and the torque winding can be connected with a power supply.

7. A magnetic levitation mixed flow cardiac pump as claimed in claim 1, wherein the axial flow vanes and centrifugal vanes are arranged in a smooth transition or separated arrangement at the connection location.