CN114768084A

CN114768084A - Spiral centrifugal impeller and blood pump

Info

Publication number: CN114768084A
Application number: CN202210440455.XA
Authority: CN
Inventors: 荆腾; 孙浩然
Original assignee: Zhongke Runteng Medical Technology Suzhou Co ltd
Current assignee: Zhongke Runteng Medical Technology Suzhou Co ltd
Priority date: 2022-04-25
Filing date: 2022-04-25
Publication date: 2022-07-22

Abstract

The invention discloses a spiral centrifugal impeller, which comprises a hub and at least one continuous spiral blade, wherein the continuous spiral blade is coaxially arranged with the hub and fixedly installed on the hub, the hub is provided with a through hole coaxial with the spiral blade, each spiral centrifugal blade comprises a working surface and a back surface, the working surface is a three-dimensional curved surface, the contour line of the working surface comprises an inlet edge, an outer edge molded line, a hub molded line and an outlet edge, the inlet edge and the outlet edge are linearly arranged, the thickness section of each spiral centrifugal blade is narrowed along the direction from the outer edge to the hub, the working surface and the back surface are connected at the outer edge molded line by a connecting surface, the connecting surface is obliquely arranged up and down along the direction from the back surface to the working surface and has an inclination angle alpha, the inclination angle alpha is gradually reduced to 0 degree in the spiral direction from the inlet edge to the outlet edge, and the length of the outlet edge is smaller than that of the inlet edge. The invention comprises at least the following advantages: can avoid the generation of hemolysis and greatly improve the blood compatibility of the blood pump.

Description

Spiral centrifugal impeller and blood pump

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a spiral centrifugal impeller and a blood pump.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

The heart auxiliary device is an artificial organ which can partially or completely replace the natural heart function and maintain the normal blood circulation of a human body. In fact, it is a mechanical device for conveying the blood flow, which can be understood as a mechanical pump, also called blood pump. The Ventricular Assist Device (VAD) partially replaces the natural heart function and is mainly used for treating acute myocarditis, myocardial infarction, temporary cardiac dysfunction and other diseases and assisting the heart to recover the normal function; the Heart replacement is called Total Artificial Heart (TAH) which totally replaces Heart function, can be used as a transition means for a patient with end-stage Heart failure to wait for Heart transplantation, and more importantly, is used for a patient with Heart failure without a Heart donor or a Heart transplantation contraindication to replace a natural Heart for long-term assistance. In terms of technology, there are two main types of research on artificial hearts: firstly, the artificial heart is developed by utilizing the bionics principle, and the working principle is similar to that of a natural heart; and the second one is a blood pump different from the natural heart mechanism, mainly a rotary blood pump (also called as an impeller pump). The former is most typically a diaphragm pump, which has inlet and outlet valves, and delivers blood by means of the change of the blood pump chamber, usually by means of a bulky drive. Currently, the more well-known diaphragm pumps are of the Berlin Heart, TCI and Novacor types. However, the diaphragm pump cannot achieve implantability due to its large volume, and its development is greatly limited. The latter typically includes axial blood pump, centrifugal blood pump, etc. which use motor to drive the impeller and other parts to rotate to drive blood flow and reach the aim of conveying blood. The blood pump of the latter type does not need a valve, has the advantages of small volume, light weight, simple structure, high reliability, low cost and the like, and is the main development direction of the implanted artificial heart. Axial blood pumps mainly comprise Jarvik2000, MicroMed DeBakey, Thoratec Heart II and the like, and Centrifugal blood pumps are widely applied to Biomedicus BP series, Thoratec Heart III, Tokyo Medical/Dental Central throttle and the like.

However, most of the blades of the existing centrifugal blood pump are completely radial blades, and the radial blades have large shearing stress when contacting blood, so that a serious hemolysis condition occurs, and a patient is suffered from cerebral apoplexy. With the rapid increase of the current heart failure patients and the advance of the technology, a spiral centrifugal impeller is urgently needed to reduce the hemolysis level in the blood pump, improve the performance and the reliability of the blood pump and benefit more heart failure patients.

It should be noted that the above description of the background art is provided for the sake of clarity and complete description of the technical solutions of the present invention, and for the understanding of those skilled in the art. These solutions are not considered to be known to the person skilled in the art merely because they are set forth in the background section of the invention.

Disclosure of Invention

The invention aims to provide a spiral centrifugal impeller and a blood pump, which can avoid hemolysis and greatly improve the blood compatibility of the blood pump.

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

a spiral centrifugal impeller comprises a hub and at least one continuous spiral blade which is coaxially arranged on the hub and is detachably and fixedly installed on the hub, the hub is provided with a through hole coaxial with the spiral blade, each spiral centrifugal blade comprises a working face and a back face which is arranged back to back on the working face, the working face is a three-dimensional space curved face, the outline of the working face comprises an inlet edge, an outer edge molded line, a hub molded line and an outlet edge, the inlet edge and the outlet edge are linearly arranged, the outer edge molded line and the hub molded line are Archimedes spiral lines, the thickness section of the spiral centrifugal blade is narrowed in the direction from the outer edge to the hub, the working face and the back face are connected through a connecting face at the outer edge molded line, the connecting face is inclined up and down in the direction from the back face to the working face and has an inclination angle alpha, the inclination angle alpha is gradually reduced to 0 degree in the spiral direction from the inlet edge to the outlet edge, and the length of the outlet edge is smaller than the length of the inlet edge.

Furthermore, the setting angle of the helical blade is gradually reduced from the outlet edge to the inlet edge, and the blade setting angle of the hub molded line on the same axial plane is smaller than that of the outer edge molded line.

Furthermore, the placing angles of the hub molded line and the outer edge molded line at the outlet edge are both 15-45 degrees.

Furthermore, the placement angles of the hub molded line and the outer edge molded line at the outlet edge are both 25 degrees.

Furthermore, the axial length of the spiral centrifugal impeller is 12-17mm, the length of the outlet edge is 4-6mm, the length of the inlet edge is 6-8mm, the outer diameter of the spiral blade is 25-35mm, and the diameter of the inlet of the spiral blade is 10-12 mm.

Further, the inclination angle of the blade on the outer edge side is 87 degrees, the inclination angle of the blade on the hub side is 90 degrees, the radius of the arc on the outer edge side is 6.4mm, and the radius of the arc on the hub side is 11.8 mm.

Furthermore, the thickness of the spiral blade close to the outer edge is 1-2mm, and the thickness of the spiral blade close to the hub is 1.5-3 mm.

Further, one surface of the hub, facing the helical blade, is provided with a tapered groove, the helical blade is mounted in the tapered groove, and the diameter of the hub is matched with that of the helical blade.

Further, the spiral centrifugal blade includes two, two spiral centrifugal blade evenly arranges and the looks lock sets up along the circumference clearance.

A blood pump comprises the spiral centrifugal impeller, a pump shell and a driving motor, wherein the pump shell is connected with the shell of the motor in a sealing mode, the pump shell is provided with an inner cavity for accommodating the spiral centrifugal impeller, and a hub is connected with an output shaft of the driving motor to be driven by the output shaft to rotate.

By means of the technical scheme, the beneficial effects of the invention are as follows:

1. the spiral blade structure of the invention can ensure that blood is sucked into the blades at a smooth angle, the shearing force between the blood and the blades is smaller, and the hemolysis level can be reduced. Meanwhile, the working surface and the back surface of the blade are connected through the inclined surface, so that the clearance between the blade and the pump shell is a constant value, and the possibility of friction between the blade and the pump shell due to vibration is reduced.

2. The invention adopts a smaller outlet placing angle to improve the working efficiency of the blade and reduce the severity of the vortex in the pump.

3. The blade inclination angle almost parallel to the horizontal line enables the pressure to be uniformly distributed in the volute when blood flows out of the impeller, and the flow field in the pump is smooth.

4. The thickness of the spiral blade close to the outer edge is 1-2mm, and the thickness of the spiral blade close to the hub is 1.5-3mm, so that the spiral blade can maintain enough strength under the condition of high-speed rotation and cannot be cracked.

5. The diameter of the hub is matched with that of the helical blade, so that the hub and the blade are the same in diameter, easy to process and good in integrity. The conical recesses allow the blades to be sufficiently stable at high rotational speeds.

6. The double-blade design of the invention can ensure that the blades can better control blood, greatly reduce the low-speed area on the back of the blades and reduce the possibility of thrombus.

7. The pump shell and the motor shell are connected in a sealing mode, so that blood cannot leak into the motor and out of the pump shell, and the sealing performance is good. The output shaft drives the impeller to rotate, so that the motor loss can be reduced to a lower level.

8. The spiral centrifugal blade can be used as a blade in an ECMO circulating blood pump and can also be used as an impeller of a left heart auxiliary centrifugal blood pump, the reduction of the shearing stress of the working surface and the back surface of the blade can be reduced by the spiral centrifugal structural design, the damage to blood cells is reduced, the required hydraulic performance is met, and the blood compatibility of the blood pump is improved.

Drawings

Fig. 1 is a cross-sectional view of a helical centrifugal impeller of the present invention mounted on a centrifugal blood pump.

Fig. 2 is a sectional view of the spiral centrifugal impeller and the disk structure of the present invention.

FIG. 3 is a schematic three-dimensional structure of a single helical centrifugal blade according to the present invention.

Fig. 4 is a schematic top view of a single helical centrifugal blade according to the present invention.

Fig. 5 is a schematic bottom view of a single helical centrifugal blade according to the present invention.

FIG. 6 is a schematic side view of a single helical centrifugal blade according to the present invention.

Fig. 7 is a schematic three-dimensional structure diagram of the double blades of the helical centrifugal impeller of the present invention.

Fig. 8 is a schematic top view of the double blades of the helical centrifugal impeller of the present invention.

Fig. 9 is a schematic structural view of the double blades of the helical centrifugal impeller in a bottom view.

Fig. 10 is a schematic side view of the double-blade structure of the screw centrifugal impeller of the present invention.

FIG. 11 is an axial plane projection of the helical centrifugal blade of the present invention.

Wherein:

1. a pump housing; 2. a helical centrifugal impeller; 3. a drive motor; 2.1, helical blades; 2.2, a hub; 2.3, through holes; 2.4, connecting surface; 2.5, a working surface; 2.6, back; 2.7, a blade wheel disk surface; 3.1, an output shaft; 12.1, inclination angle of the blade on the wheel rim side; 12.2, the inclination angle of the blade on the hub side; 12.3, rim side arc; 12.4, a hub side arc; 12.5, an outlet side; 12.6, the inlet edge.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, in the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and to distinguish similar objects, and there is no order between the two, and no indication or implication of relative importance should be understood. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

The centrifugal blood pump can provide extracorporeal blood circulation for patients with severe heart failure and lack of heart donors, maintain the life of the patients and prolong the waiting time of the heart donors. With reference to the accompanying fig. 1-11, a screw centrifugal impeller 2 comprises a hub 2.2 and at least one continuous screw blade 2.1 arranged coaxially with said hub 2.2 and removably fixedly mounted on said hub 2.2, in which fig. 5 is shown a bottom view of the screw centrifugal blade, wherein 2.7 is the vane wheel disc surface, referring to fig. 1-6, in one embodiment, in order to make the helical vane 2.1 better control blood, greatly reduce the shear stress generated at the positions of the vane connecting surface 2.4 and the outlet edge 12.5, reduce the possibility of hemolysis, the helical vane 2.1 is a piece, in other embodiments, the spiral blades 2.1 are 2 pieces, two pieces of spiral centrifugal blades are arranged along the circumferential gap and are buckled with each other, the buckling arrangement is similar to the mosquito coil incense, but there are gaps between the 2 blades of the present application, see fig. 7-10. The utility model provides a wheel hub 2.2 seted up with the coaxial through-hole 2.3 of helical blade 2.1, every helical centrifugal blade include working face 2.5 and with back 2.6 that working face 2.5 set up mutually, working face 2.5 be the three-dimensional space curved surface, the profile line of working face 2.5 includes import limit 12.6, outer fringe molded lines, wheel hub 2.2 molded lines and export limit 12.5, import limit 12.6 is the straight line setting with export limit 12.5, the outer fringe molded lines with wheel hub 2.2 molded lines are archimedes's helix, helical centrifugal blade's thickness cross-section narrows down the setting along outer fringe to wheel hub 2.2 direction, is connected by a connecting face 2.4 in outer fringe molded lines department between working face 2.5 and the back 2.6, connecting face 2.4 inclines about back 2.6 to working face 2.5 direction and sets up and has angle of inclination alpha, see figure 10, angle of inclination alpha reduce gradually for 0 in the helical direction of import limit 12.6 to export limit 12.5, the length of the outlet edge 12.5 is smaller than that of the inlet edge 12.6, the Archimedes spiral blades can enable blood to be sucked into the spiral blades 2.1 at a smooth angle, the shearing force between the blood and the spiral blades 2.1 is small, and the hemolysis level can be reduced. Meanwhile, the working surface 2.5 and the back surface 2.6 of the helical blade 2.1 are connected through the inclined surface, so that the clearance between the blade and the pump shell 1 is a constant value, and the possibility of friction between the blade and the pump shell 1 due to vibration is reduced. Fig. 1 shows an embodiment of the application of a helical centrifugal impeller 2 according to the invention to a centrifugal blood pump.

Specifically, in order to reduce the severity of the vortex in the pump, the pitch angle of the helical blade 2.1 of the present application is gradually reduced from the outlet edge 12.5 to the inlet edge 12.6, and the blade pitch angle of the hub 2.2 profile on the same axial plane is smaller than the blade pitch angle of the outer edge profile. The setting angles of the hub 2.2 molded line and the outer edge molded line at the outlet edge 12.5 are both 15-45 degrees, and in the embodiment, the setting angles of the hub 2.2 molded line and the outer edge molded line at the outlet edge 12.5 are preferably both 25 degrees, because the smaller outlet setting angle can improve the working efficiency of the blade and reduce the severity of the vortex in the pump.

In order to ensure that the pressure is uniformly distributed in the volute when the blood flows out of the spiral impeller and the flow in the pump is smoother, the spiral blade 2.1 can maintain enough strength under the condition of high-speed rotation and can not be cracked, the axial length of the spiral centrifugal impeller 2 is preferably 12-17mm, the length of the outlet edge 12.5 is preferably 4-6mm, the length of the inlet edge 12.6 is preferably 6-8mm, the outer diameter of the spiral blade 2.1 is 25-35mm, the diameter of the inlet of the spiral blade 2.1 is 10-12mm, the thickness of the outer edge side is 1-2mm, and the thickness of the hub 2.2 side is preferably 1.5-3 mm. The inclination angle of the blade at the outer edge side is 87 degrees, the inclination angle of the blade at the 2.2 side of the hub is 90 degrees, the radius of the arc at the outer edge side is 6.4mm, and the radius of the arc at the 2.2 side of the hub is 11.8 mm.

For the convenience of processing, the integrity is better, and the helical blade 2.1 is ensured to be stable enough when rotating at high speed, preferably, the side of the hub 2.2 facing the helical blade 2.1 is provided with a conical concave surface, the helical blade 2.1 is arranged in the conical concave surface, and the diameter of the hub 2.2 is matched with the diameter of the helical blade 2.1.

A blood pump comprises the spiral centrifugal impeller 2, a pump shell 1 and a driving motor 3, in order to prevent obtained blood from leaking into the motor and out of the pump shell 1, the pump shell 1 is hermetically connected with a stator shell of the motor, the pump shell 1 is provided with an inner cavity for accommodating the spiral centrifugal impeller 2, and a hub 2.2 is connected with an output shaft 3.1 of the driving motor 3 so as to be driven by the output shaft 3.1 to rotate. Specifically, the spiral centrifugal blade of this application can regard as the blade use among the ECMO circulating blood pump, also can be used for using as the impeller of the supplementary centrifugal blood pump of left heart, and the centrifugal structural design of spiral can reduce the reduction of the shear stress of blade working face 2.5 and back 2.6, reduces the destruction that causes the blood cell, when satisfying the hydraulic performance of needs, has improved the blood compatibility of blood pump.

The application of the drive motor 3 adopts a brushless motor, the centrifugal force generated by the rotation of the spiral impeller flows blood from the outlet of the pump to make the blood flow out from the outlet of the blood pump, and the negative pressure in the pump sucks the blood at the inlet of the pump into the pump so as to form circulation. The spiral centrifugal blade, the hub 2.2 and the pump shell 1 are all made of materials with good blood compatibility, such as pure titanium, titanium alloy, polytetrafluoroethylene and the like. The 2.2 axle centers of wheel hub are equipped with through-hole 2.3, can flow to the pump export through the effect of impeller centrifugal force with the blood in the clearance between motor rotor and the output shaft 3.1 (stator), form internal circulation, prevent that blood from forming the blind spot between rotor and stator and causing the thrombus.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.

Claims

1. A spiral centrifugal impeller is characterized by comprising a hub and at least one continuous spiral blade which is coaxially arranged on the hub and is detachably and fixedly installed on the hub, the hub is provided with through holes coaxial with the spiral blade, each spiral centrifugal blade comprises a working face and a back face which is back to back with the working face, the working face is a three-dimensional space curved face, the outline of the working face comprises an inlet edge, an outer edge molded line, a hub molded line and an outlet edge, the inlet edge and the outlet edge are linearly arranged, the outer edge molded line and the hub molded line are Archimedes spiral lines, the thickness section of the spiral centrifugal blade is narrowed along the direction from the outer edge to the hub, the working face and the back face are connected through a connecting face, the connecting face is inclined up and down along the direction from the back face to the working face and has an inclination angle alpha, the inclination angle alpha is gradually reduced to 0 degree in the spiral direction from the inlet edge to the outlet edge, and the length of the outlet edge is smaller than the length of the inlet edge.

2. The helical centrifugal impeller of claim 1 wherein the pitch angle of the helical blades decreases from the outlet edge to the inlet edge, and the blade pitch angle of the hub profile on the same axial plane is less than the blade pitch angle of the outer edge profile.

3. The helical centrifugal impeller of claim 1 wherein the seating angles of the hub and rim profiles at the outlet edge are each 15-45 °.

4. The helical centrifugal impeller of claim 1 wherein the seating angle of the hub profile and the rim profile at the outlet edge are both 25 °.

5. The helical centrifugal impeller as claimed in claim 1 wherein the axial length of the helical centrifugal impeller is 12-17mm, the length of the outlet edge is 4-6mm, the length of the inlet edge is 6-8mm, the outer diameter of the helical blades is 25-35mm, and the diameter of the helical blades at the inlet is 10-12 mm.

6. The helical centrifugal impeller of claim 1 wherein the outer edge side blade angle is 87 °, the hub side blade angle is 90 °, the outer edge side arc radius is 6.4mm, and the hub side arc radius is 11.8 mm.

7. The helical centrifugal impeller of claim 1 wherein the helical blades have a thickness of 1-2mm near the outer edge and 1.5-3mm near the hub.

8. The helical centrifugal impeller of claim 1 wherein a face of said hub facing said helical blades has a conical concave surface in which said helical blades are mounted, said hub having a diameter that is adapted to a diameter of said helical blades.

9. The helical centrifugal impeller as claimed in claim 1 wherein the helical centrifugal blades comprise two pieces, the two pieces being arranged evenly with a circumferential gap and snap-fitted together.

10. A blood pump comprising the helical centrifugal impeller as claimed in any one of claims 1 to 7, further comprising a pump housing and a drive motor, the pump housing being sealingly connected to a stator housing of the motor and having an internal cavity for receiving the helical centrifugal impeller, the hub being connected to an output shaft of the drive motor for rotation by the output shaft.