CN114949586A

CN114949586A - Magnetic-liquid double-suspension mixed-flow blood pump

Info

Publication number: CN114949586A
Application number: CN202210756902.2A
Authority: CN
Inventors: 彭远仪; 张鹏; 张文; 廖鹏
Original assignee: Shanghai Dongxin Biomedical Technology Co ltd
Current assignee: Shanghai Dongxin Biomedical Technology Co ltd
Priority date: 2022-06-29
Filing date: 2022-06-29
Publication date: 2022-08-30

Abstract

The invention discloses a magnetic-liquid double-suspension mixed-flow blood pump, which comprises: the pump comprises a pump shell, an impeller, a driving motor for driving the impeller to rotate, a front magnetic bearing and a rear magnetic bearing, wherein the pump shell is provided with a pump outer pipe, a pump inner pipe coaxially nested in the pump outer pipe and a pump cavity communicated with the lower end of the pump inner pipe; the impeller comprises a front-section screw-type impeller and a rear-section vertical-blade-type impeller, the screw-type impeller is coaxially arranged in the pump inner pipe, and the vertical-blade-type impeller is arranged in the pump cavity; the vertical blade type impeller is provided with a plurality of radial vertical blades, the upper end face and the lower end face of each vertical blade are provided with inclined faces, and a wedge-shaped hydraulic pressure structure with a large flow-receiving opening and a small flow-back opening is formed between the two inclined faces on each vertical blade and the inner walls of the upper side and the lower side of the pump cavity. The magnetic-liquid double-suspension mixed-flow blood pump adopts a double-suspension mechanism of magnetic suspension and liquid-force suspension, can improve the stability and reliability of the blood pump, and greatly improves the work-doing effect.

Description

Magnetic-liquid double-suspension mixed-flow blood pump

Technical Field

The invention relates to the technical field of medical instruments, in particular to a magnetic-liquid double-suspension mixed-flow type blood pump.

Background

Artificial heart assist devices, referred to simply as "blood pumps", are considered to be the most important and promising treatment for many patients with advanced heart failure.

At present, impeller type blood pumps become mainstream products for clinical application, and the blood pumps existing in the existing market can be roughly divided into two types, namely a centrifugal blood pump and an axial flow type blood pump. Two blood pumps have the advantages and the disadvantages in the technology: the axial flow type blood pump has the advantages of large flow, small pressure head and relatively low mechanical efficiency; centrifugal blood pumps have the advantage of a large pressure head and the disadvantage of a relatively small flow. The impeller supporting modes of the existing blood pump are mainly three, the first type is a mechanical bearing type blood pump, the second type is a hydraulic suspension blood pump, and the third type is a magnetic suspension blood pump. Mechanical bearing blood pumps have been gradually replaced by two others due to their short mechanical life and relatively high complications. However, although the second and third suspension bearing structures can overcome the disadvantage of short mechanical life of the blood pump, the stability and reliability of the shock resistance are obviously insufficient.

Disclosure of Invention

In order to solve the technical problems, the invention provides a magnetic-liquid double-suspension mixed-flow blood pump, which improves the stability and reliability of the blood pump, can take the advantages of an axial-flow blood pump and a centrifugal blood pump into consideration, and has the advantages of larger pressure head and flow and greatly improved work-doing effect under the condition of the same work doing.

The technical scheme adopted by the invention for solving the technical problem is as follows: a magnetic-liquid double-suspension mixed-flow blood pump comprises:

the pump comprises a pump shell, a pump cover and a pump body, wherein the pump shell is provided with a pump outer pipe, a pump inner pipe coaxially nested in the pump outer pipe and a pump cavity communicated with the lower end of the pump inner pipe;

the impeller comprises a screw type impeller at the front section and a vertical blade type impeller at the rear section, the screw type impeller is coaxially arranged in the pump inner pipe, and the vertical blade type impeller is arranged in the pump cavity; the vertical blade type impeller is provided with a plurality of radial vertical blades, inclined planes are arranged on the upper end face and the lower end face of each vertical blade, and a wedge-shaped hydraulic structure with a large flow-receiving opening and a small flow-back opening is formed between the two inclined planes on each vertical blade and the inner walls of the upper side and the lower side of the pump cavity;

the driving motor is arranged in the pump shell and the impeller and is used for driving the impeller to rotate;

the front magnetic bearing comprises an inner magnetic core group which is arranged in the position, close to the top, of the impeller and an outer magnetic ring group which is arranged between the outer pipe of the pump and the inner pipe of the pump, and the outer magnetic ring group and the inner magnetic core group are in radial repulsion;

the rear magnetic bearing comprises an upper magnetic ring and a lower magnetic ring, wherein the upper magnetic ring is arranged at the bottom of the impeller, the lower magnetic ring is arranged in the pump cavity, and the lower magnetic ring is coaxially arranged below the upper magnetic ring and mutually attracted.

As a further improvement of the present invention, the screw-type impeller has a hub and a plurality of helical blades provided along an outer peripheral surface of the hub, and the helical blades are capable of driving blood to flow in an axial direction of the pump inner tube while rotating along with the impeller.

As a further improvement of the invention, the number of the spiral blades is 2-5; the number of the vertical blades is 3-6.

As a further improvement of the invention, the inner magnetic core group and the outer magnetic ring group are formed by forcibly splicing at least two magnetic sheets in a homopolar opposite mode;

wherein, the S pole and the N pole of the magnetic sheet are respectively positioned at the upper side and the lower side.

As a further improvement of the invention, the outer ring of the upper magnetic ring is an N pole, the inner ring is an S pole, the outer ring of the lower magnetic ring is an S pole, and the inner ring is an N pole;

or the outer ring of the upper magnetic ring is an S pole, the inner ring of the upper magnetic ring is an N pole, and the outer ring of the lower magnetic ring is an N pole and the inner ring of the lower magnetic ring is an S pole.

As a further improvement of the invention, the upper magnetic ring and the lower magnetic ring are integrated; or the upper magnetic ring and the lower magnetic ring are formed by forcibly splicing at least two fan-shaped magnetic shoes;

the magnetic shoe comprises a magnetic shoe, a magnetic core and a magnetic core, wherein the magnetic shoe is provided with an S pole and an N pole which are respectively arranged at the inner side and the outer side.

As a further improvement of the present invention, the drive motor includes a motor winding that is built in between the pump outer tube and the pump inner tube, and a motor rotor that is built in the impeller and is opposed to the motor winding.

As a further improvement of the invention, the motor rotor further comprises a plurality of magnetic shields which are arranged in the pump shell and the impeller and distributed outside the upper and lower ends of the motor winding and the motor rotor;

the magnetic shielding parts are made of iron soft magnetic materials.

As a further improvement of the invention, the inner bottom wall of the pump cavity extends inwards to form a pump cavity boss opposite to the impeller, and the lower magnetic ring is arranged in the pump cavity boss; the top of pump chamber boss is inlayed and is had ceramic ball, the potsherd is installed to the bottom of impeller, the potsherd bears on the ceramic ball.

As a further improvement of the invention, the inclination angle of the inclined plane is 1-15 degrees.

The invention has the beneficial effects that:

1. the invention provides a magnetic-liquid double-suspension mixed-flow blood pump, wherein an impeller is provided with a screw type impeller at the front section and a vertical blade type impeller at the rear section, the screw type impeller and a pump inner pipe are matched to form an axial flow pump, the vertical blade type impeller and a pump cavity are matched to form a centrifugal pump, both the axial flow pump at the front section and the centrifugal pump at the rear section do work, the axial flow pump and the centrifugal pump are combined into a mixed-flow pump, the advantages of the axial flow pump and the centrifugal pump are taken into consideration, the generated pressure head and flow are large, and the working efficiency is greatly improved;

2. the impeller keeps a radial suspension state under the combined action of the front magnetic bearing and the rear magnetic bearing, the suspension effect is good, the impact resistance is improved, and the stability and the reliability are also greatly improved;

3. inclined planes are arranged on the upper end face and the lower end face of a vertical blade of the impeller, a wedge-shaped hydraulic structure is formed by the inclined planes and the inner surface of a pump cavity, when the impeller rotates, a flow inlet of a wedge-shaped groove is large, a flow outlet of the wedge-shaped groove is small, hydraulic and automatically-adjusted liquid suspension can be generated, the impeller keeps axial suspension, and the radial suspension and the axial suspension of the impeller can realize omnibearing position control suspension, so that the impeller can stably operate;

4. the double-suspension mechanism of adding the magnetic suspension and the hydraulic suspension is adopted, so that the stability and the reliability of the blood pump can be improved, and hemolysis and thrombosis complications can be reduced; meanwhile, the volume and the weight of the blood pump are smaller, so that the operation invasion of the blood pump can be reduced, and the practicability of the blood pump is improved.

Drawings

FIG. 1 is a sectional view of a magnetic-fluid double-suspension mixed-flow type blood pump of the present invention;

FIG. 2 is a front view of an impeller in the magnetic-fluid double-suspension mixed-flow blood pump of the present invention;

FIG. 3 is a perspective view of a vertical blade impeller of the impeller in the magnetic-fluid double-suspension mixed-flow type blood pump of the present invention;

FIG. 4 is a schematic structural diagram of a rear magnetic bearing in the magnetic-liquid double-suspension mixed-flow type blood pump of the present invention;

FIG. 5 is a top view of an upper magnetic ring of the magnetic-fluid double-suspension mixed-flow type blood pump of the present invention assembled with three magnetic shoes;

wherein, the direction indicated by the arrow in fig. 3 is the rotation direction of the impeller when the blood pump is working.

The following description is made with reference to the accompanying drawings:

1. a pump housing; 101. an outer pump tube; 102. a pump inner tube; 103. a pump chamber; 2. an impeller; 201. a vertical blade; 2011. an inclined surface; 202. a hub; 203. a helical blade; 3. a drive motor; 301. a motor winding; 302. a motor rotor; 4. a front magnetic bearing; 401. the inner magnetic core group; 402. an outer magnetic ring set; 5. a rear magnetic bearing; 501. an upper magnetic ring; 502. a lower magnetic ring; 6. ceramic balls; 7. a ceramic plate; 8. a magnetic shield.

Detailed Description

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to fig. 1 to 5, the present invention provides a magnetic-liquid double-suspension mixed-flow blood pump, comprising: the device comprises a pump shell 1, an impeller 2, a driving motor 3, a front magnetic bearing 4, a rear magnetic bearing 5, a positioning ceramic bearing and a plurality of magnetic shields 8.

Wherein, pump housing 1 is provided with pump outer tube 101, pump inner tube 102 and pump chamber 103, and pump outer tube 101 and pump inner tube 102 are all along vertical arrangement, and pump inner tube 102 is coaxial nested in pump outer tube 101 to there is the accommodation space between the two, and this accommodation space is arranged in installing driving motor 3 and the preceding part in the magnetic bearing 4. The pump chamber 103 is provided below the pump inner tube 102 and communicates with the lower end of the pump inner tube 102; the pump housing 1 is further provided with a pump outlet on the side of the pump chamber 103, which is in communication with the pump chamber 103 for the outflow of blood. The upper end of the pump inner tube 102 is a blood inflow port, the top of the pump outer tube 101 is provided with an inlet support, and the inlet support extends to the upper side of the pump inner tube 102, so that the pump is prevented from being out of work and being plugged due to the fact that ventricular septum is sucked by negative pressure when the blood pump works.

Referring to fig. 1 to 3, the impeller 2 includes a screw-type impeller of a front stage and a vertical blade-type impeller of a rear stage. A screw-type impeller having a hub 202 and a plurality of helical blades 203 provided along the outer peripheral surface of the hub 202 is coaxially arranged within the pump inner tube 102. Optionally, the number of the helical blades 203 is 2-5. The spiral blade 203 can drive blood to flow into the pump chamber 103 along the axial direction of the pump inner tube 102 while following the rotational movement of the impeller 2. The vertical blade type impeller is welded at the lower end of the screw type impeller in a seamless mode and is arranged in the pump cavity 103. The vertical blade type impeller is provided with a plurality of radial vertical blades 201 with radians, and optionally, the number of the vertical blades 201 is 3-6. When the vertical vanes 201 rotate along with the impeller 2, the blood in the pump cavity 103 can be driven to flow along the radial direction of the impeller 2, so that the blood flows out of the pump outlet.

Further, a driving motor 3 is built in the pump housing 1 and the impeller 2 for driving the impeller 2 to rotate. Specifically, the driving motor 3 includes a motor winding 301 and a motor rotor 302, and the motor winding 301 is embedded in the accommodating space between the pump outer tube 101 and the pump inner tube 102. The motor rotor 302 is a 2-pole or 4-pole magnetic core, is arranged in the middle of the screw type impeller of the impeller 2 and is connected with the impeller 2 into a whole, and the motor rotor 302 and the motor winding 301 are arranged oppositely, so that the driving motor 3 and the liquid pump are integrated into a whole, and further, the pump-motor integration is formed.

This application constitutes the axial-flow pump through adopting screw impeller and pump inner tube 102 cooperation, and found piece formula impeller and pump chamber 103 cooperation and constitute the centrifugal pump, under driving motor 3's drive, impeller 2 rotates, and the axial-flow pump of anterior segment and the centrifugal pump of back end all do work, and the two combination is mixed flow pump, and efficiency improves greatly.

Referring to fig. 1, the front magnetic bearing 4 includes an inner magnetic core set 401 and an outer magnetic ring set 402, the inner magnetic core set 401 is built in the impeller 2 near the top, the outer magnetic ring set 402 is built in the accommodating space between the pump outer tube 101 and the pump inner tube 102, and the outer magnetic ring set 402 and the inner magnetic core set 401 are arranged oppositely. The inner magnetic core group 401 and the outer magnetic ring group 402 are formed by forcibly splicing at least two magnetic sheets in a homopolar opposite mode, and the S pole and the N pole of each magnetic sheet are respectively positioned at the upper side and the lower side.

In detail, in a preferred embodiment, the inner magnetic core set 401 is composed of, but not limited to, three circular magnetic sheets stacked together, the first circular magnetic sheet has an S-pole upper layer and an N-pole lower layer, the second circular magnetic sheet has an N-pole upper layer and an S-pole lower layer, and the third circular magnetic sheet has an S-pole upper layer and an N-pole lower layer, so that the three circular magnetic sheets are relatively and forcibly spliced into a whole. The outer magnetic ring set 402 is formed by stacking, but not limited to, three circular magnetic rings, the first circular magnetic ring is arranged to have an upper layer as an S pole and a lower layer as an N pole corresponding to the inner magnetic core set 401, the second circular magnetic ring has an upper layer as an N pole and a lower layer as an S pole, the third circular magnetic ring has an upper layer as an S pole and a lower layer as an N pole, and the three circular magnetic rings are relatively and forcibly spliced into a whole by the upper layer as an S pole and the lower layer as an N pole. Wherein, three circular magnetic sheets and three circular magnetic rings are corresponding to each other in the horizontal direction, or slightly offset from top to bottom, so that the outer magnetic ring group 402 and the inner magnetic core group 401 are radially repelled, and further the upper end of the impeller 2 is radially positioned in the middle, and the upper end of the impeller 2 is kept in a radial suspension state.

With continued reference to fig. 1, the rear magnetic bearing 5 includes an upper magnetic ring 501 built into the bottom of the screw impeller and a lower magnetic ring 502 built into the pump chamber 103. The inner bottom wall of the pump cavity 103 extends inwards to form a pump cavity boss opposite to the impeller 2, the lower magnetic ring 502 is fixed in the pump cavity boss, the lower magnetic ring 502 is coaxially arranged right below the upper magnetic ring 501, and the lower magnetic ring 502 and the upper magnetic ring 501 are mutually attracted in the axial direction.

Referring to fig. 4, the inner and outer diameters of the upper magnetic ring 501 are matched with the inner and outer diameters of the lower magnetic ring 502, the outer ring of the upper magnetic ring 501 is an N pole, the inner ring is an S pole, the outer ring of the lower magnetic ring 502 is an S pole, and the inner ring is an N pole; or the outer ring of the upper magnetic ring 501 is an S pole, the inner ring is an N pole, the outer ring of the lower magnetic ring 502 is an N pole, and the inner ring is an S pole. By adopting the structural design, the upper magnetic ring 501 and the lower magnetic ring 502 are arranged to be a magnetic pole at the outer ring and a magnetic pole at the inner ring, and the magnetic poles at the inner ring and the outer ring of the upper magnetic ring 501 are opposite to the magnetic poles at the inner ring and the outer ring of the lower magnetic ring 502, so that the outer ring of the upper magnetic ring 501 and the outer ring of the lower magnetic ring 502 are attracted, the inner ring of the upper magnetic ring 501 and the inner ring of the lower magnetic ring 502 are also attracted, and the two are concentric by virtue of attraction, so that the lower end of the impeller 2 is centered radially; even if the impeller 2 is deviated and eccentric up and down, the repulsive force is acted when the attractive force acts, so that the upper magnetic ring 501 returns to the central position again, namely, the impeller 2 is ensured to be centered. The impeller 2 keeps a radial suspension state under the combined action of the front magnetic bearing 4 and the rear magnetic bearing 5, the suspension effect is good, the impact resistance is improved, and the stability and the reliability are also greatly improved.

The magnetic materials adopted by the inner magnetic core group 401, the outer magnetic ring group 402, the upper magnetic ring 501 and the lower magnetic ring 502 are strong magnetic neodymium iron boron.

It can be understood that the upper magnetic ring 501 and the lower magnetic ring 502 can be integrated, or can be formed by forcibly splicing at least two fan-shaped magnetic tiles; wherein, the S pole and the N pole of the magnetic shoe are respectively arranged at the inner side and the outer side.

As shown in fig. 5, in an embodiment, the upper magnetic ring 501 is composed of three identical magnetic tiles, an outer arc of each magnetic tile is an S pole, an inner arc of each magnetic tile is an N pole, and the N poles of the three magnetic tiles are opposite to each other, and the S poles of the three magnetic tiles are opposite to each other, so that the three magnetic tiles are forcibly spliced into the annular upper magnetic ring 501. Of course, the upper magnetic ring 501 may also be formed by splicing two, four or even more pieces, which all can achieve the same function, and the description is not repeated here.

The positioning ceramic bearing comprises a ceramic ball 6 and a ceramic plate 7, wherein the ceramic ball 6 is embedded at the top of the pump cavity boss, and at least part of the ceramic ball is protruded to the outside. The ceramic plate 7 is fixedly arranged at the bottom of the screw type impeller and attached to the bottom surface of the upper magnetic ring 501, and the ceramic plate 7 is loaded on the ceramic ball 6. When the blood pump is started to a certain speed, the impeller 2 is axially suspended, and the ceramic chip 7 is separated from the ceramic ball 6.

A plurality of magnetic shields 8 are installed in the pump housing 1 and the impeller 2 and distributed outside the upper and lower ends of the motor winding 301 and the motor rotor 302. Specifically, a plurality of magnetism shields 8 include last magnetism shielding ring, down magnetism shielding ring, go up magnetism shielding circle and down magnetism shielding circle, go up magnetism shielding ring and set up between motor winding 301 and outer magnetism ring group 402, down magnetism shielding ring sets up between the upper cover of motor winding 301 and pump chamber 103, goes up magnetism shielding circle and sets up between motor rotor 302 and interior magnetism core group 401, and down magnetism shielding circle is between motor rotor 302 and last magnetism ring 501. Wherein, the magnetic shielding pieces 8 are made of iron soft magnetic materials.

Referring to fig. 3, in the present application, inclined surfaces 2011 are respectively disposed on upper and lower end surfaces of the plurality of vertical blades 201, two inclined surfaces 2011 on the upper and lower sides of each vertical blade 201 and an inner wall of an upper cavity and an inner wall of a lower cavity of the pump cavity 103 respectively form a wedge-shaped groove, and the wedge-shaped grooves are large in incident flow port and small in back flow port along the rotation direction. After the impeller 2 rotates, incompressible liquid flow enters the wedge-shaped groove from the flow inlet, hydraulic pressure is generated due to extrusion, the size of the hydraulic pressure is positively correlated with the rotating speed of the impeller 2, and is positively correlated with the included angle of the wedge-shaped groove and negatively correlated with the wedge-shaped space.

It should be noted that the wedge-shaped spaces of the wedge-shaped grooves on the upper and lower sides of the vertical vane 201 change along with the vertical displacement of the impeller 2, and the closer the inclined surface 2011 of the vertical vane 201 is to the inner wall of the cavity of the pump cavity 103, the larger the hydraulic pressure generated, and conversely, the smaller the hydraulic pressure. The thrust generated by the hydraulic pressure at the upper end and the lower end of the vertical blade 201 is a set of axial forces with opposite directions, and the set of forces can be automatically adjusted along with the change of the upper wedge-shaped space and the lower wedge-shaped space of the impeller 2 to axially suspend the impeller 2, so the axial suspension belongs to self-suspension. That is to say, in a certain rotating speed range, the axial stress of the impeller 2 can be automatically balanced and automatically suspended axially.

Optionally, the inclined angle of the inclined surface 2011 is 1-15 °.

As described above, the impeller 2 can be suspended in all directions by radial suspension and axial suspension, so that the operation can be performed stably.

For ease of understanding, the axial force to which the impeller 2 is subjected during operation of the blood pump is analysed. The method mainly comprises the following steps:

the first axial force is the impulse force of the liquid flow at the inlet of the blood pump to the impeller 2, the direction is axial downward, and the size is positively correlated with the rotating speed;

the second axial force is thrust generated by the pressure difference between the blood outlet and the blood inlet of the blood pump, the direction is axial and upward, and the magnitude is positively correlated with the rotating speed;

the third axial force, the axial component of the gravity of the motor rotor 302 and the impeller 2, is downward in direction, and the magnitude is only changed along with the posture adjustment of the blood pump;

the direction of the fourth axial force, namely the axial thrust generated by the front magnetic bearing 4 to the impeller 2, is upward or downward, and the magnitude and the direction can be changed along with the upward and downward offset positions of the inner magnetic core group 401 and the outer magnetic ring group 402;

the fifth axial force, the axial supporting force of the ceramic balls 6, is upward, and the force disappears after the impeller 2 is suspended;

the sixth axial force, the axial suction force generated by the rear magnetic bearing 5 to the impeller 2, is downward;

a seventh axial force, which is an axial thrust of the hydraulic pressure generated in the wedge-shaped groove on the upper side of the vertical blade 201, and the direction of the seventh axial force is axially downward;

the eighth axial force is an axial thrust of the hydraulic pressure generated in the wedge groove on the lower side of the vertical vane 201, and the direction thereof is axially upward.

The magnitude of the seventh axial force and the magnitude of the eighth axial force are positively correlated with the rotating speed, positively correlated with the wedge-shaped included angle, negatively correlated with the magnitude of the wedge-shaped space and in exponential relation. The first axial force to the sixth axial force are passive forces and weak influence forces; the seventh axial force and the eighth axial force are main forces and are strong influence forces, the seventh axial force and the eighth axial force automatically keep balance under the condition of overcoming the first axial force to the sixth axial force, and the axial suspension of the motor rotor 302 and the impeller 2 is ensured when the sum of the axial force vectors is kept zero.

Therefore, compared with the existing mechanical bearing blood pump, the motor rotor 302 and the impeller 2 of the blood pump are in an omnibearing position control suspension state when the blood pump works normally, the bearing has no friction, hemolysis can be reduced, the service life of the blood pump is prolonged, and thrombus complications triggered by friction heating can be reduced.

Compare with current centrifugal blood pump and axial-flow type blood pump, the advantage of axial-flow type blood pump and centrifugal blood pump can be compromise to this application, overcomes the shortcoming of the two, and under the condition of same doing work, the pressure head and the flow that produce are all great, and the efficiency of doing work promotes greatly.

Compare with current liquid suspension blood pump and magnetic suspension blood pump, this application adopts the two suspension mechanisms of magnetic force suspension liquid feeding power suspension, can improve the stability and the reliability of blood pump.

In addition, the volume and the weight of this application blood pump are less, can reduce the operation invasion nature of blood pump, improve the practicality, and the succinct smoothness of inner structure of this kind of full suspension formula blood pump does not have dead space or dead angle moreover, also can prevent thrombosis effectively.

In the previous description, numerous specific details were set forth in order to provide a thorough understanding of the present invention. The foregoing description is only a preferred embodiment of the invention, which can be embodied in many different forms than described herein, and therefore the invention is not limited to the specific embodiments disclosed above. And that those skilled in the art may, using the methods and techniques disclosed above, make numerous possible variations and modifications to the disclosed embodiments, or modify equivalents thereof, without departing from the scope of the claimed embodiments. Any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. The utility model provides a magnetism liquid double suspension mixed flow blood pump which characterized in that includes:

the pump casing (1) is provided with a pump outer pipe (101), a pump inner pipe (102) coaxially nested in the pump outer pipe (101), and a pump cavity (103) communicated with the lower end of the pump inner pipe (102);

the impeller (2) comprises a screw type impeller at the front section and a vertical blade type impeller at the rear section, the screw type impeller is coaxially arranged in the pump inner pipe (102), and the vertical blade type impeller is arranged in the pump cavity (103); the vertical blade type impeller is provided with a plurality of radial vertical blades (201), inclined planes (2011) are arranged on the upper end face and the lower end face of each vertical blade (201), and a wedge-shaped hydraulic pressure structure with a large incident flow port and a small back flow port is formed between the two inclined planes (2011) on each vertical blade (201) and the inner walls of the upper side and the lower side of the pump cavity (103);

the driving motor (3) is arranged in the pump shell (1) and the impeller (2) and is used for driving the impeller (2) to rotate;

the front magnetic bearing (4) comprises an inner magnetic core group (401) which is arranged in the position, close to the top, of the impeller (2) and an outer magnetic ring group (402) which is arranged between the outer pump pipe (101) and the inner pump pipe (102), and the outer magnetic ring group (402) and the inner magnetic core group (401) are in radial repulsion;

the rear magnetic bearing (5) comprises an upper magnetic ring (501) and a lower magnetic ring (502), the upper magnetic ring (501) is arranged at the bottom of the impeller (2) in a built-in mode, the lower magnetic ring (502) is arranged in the pump cavity (103) in a coaxial mode, and the upper magnetic ring (501) and the lower magnetic ring (502) are arranged below the lower magnetic ring and attract each other.

2. The magnetic-liquid double-suspension mixed-flow type blood pump of claim 1, characterized in that: the screw-type impeller is provided with a hub (202) and a plurality of helical blades (203) arranged along the outer peripheral surface of the hub (202), and the helical blades (203) can drive blood to flow along the axial direction of the pump inner tube (102) when rotating along with the impeller (2).

3. The magnetic-liquid double-suspension mixed-flow type blood pump of claim 2, characterized in that: the number of the spiral blades (203) is 2-5; the number of the vertical blades (201) is 3-6.

4. The magnetic-liquid double-suspension mixed-flow type blood pump of claim 1, characterized in that: the inner magnetic core group (401) and the outer magnetic ring group (402) are formed by forcibly splicing at least two magnetic sheets in a homopolar opposite mode;

5. The magnetic-liquid double-suspension mixed-flow type blood pump according to claim 1, characterized in that: the outer ring of the upper magnetic ring (501) is an N pole, the inner ring of the upper magnetic ring is an S pole, the outer ring of the lower magnetic ring (502) is an S pole, and the inner ring of the lower magnetic ring is an N pole;

or the outer ring of the upper magnetic ring (501) is an S pole, the inner ring of the upper magnetic ring is an N pole, the outer ring of the lower magnetic ring (502) is an N pole, and the inner ring of the lower magnetic ring is an S pole.

6. The magnetic-liquid double-suspension mixed-flow type blood pump of claim 5, wherein: the upper magnetic ring (501) and the lower magnetic ring (502) are integrated; or the upper magnetic ring (501) and the lower magnetic ring (502) are formed by forcedly splicing at least two fan-shaped magnetic tiles;

7. The magnetic-liquid double-suspension mixed-flow type blood pump of claim 1, characterized in that: the driving motor (3) comprises a motor winding (301) and a motor rotor (302), the motor winding (301) is arranged between the pump outer tube (101) and the pump inner tube (102), and the motor rotor (302) is arranged in the impeller (2) and is opposite to the motor winding (301).

8. The magnetic-liquid double-suspension mixed-flow type blood pump according to claim 7, characterized in that: the magnetic shielding parts (8) are arranged in the pump shell (1) and the impeller (2) and are distributed outside the upper end and the lower end of the motor winding (301) and the motor rotor (302);

the magnetic shielding pieces (8) are made of iron soft magnetic materials.

9. The magnetic-liquid double-suspension mixed-flow type blood pump of claim 1, characterized in that: the inner bottom wall of the pump cavity (103) extends inwards to form a pump cavity boss right opposite to the impeller (2), and the lower magnetic ring (502) is arranged in the pump cavity boss; ceramic ball (6) are inlayed at the top of pump chamber boss, potsherd (7) are installed to the bottom of impeller (2), potsherd (7) bear on ceramic ball (6).

10. The magnetic-liquid double-suspension mixed-flow type blood pump of claim 1, characterized in that: the inclination angle of inclined plane (2011) is 1 ~ 15.