Centrifugal blood pump rotor and centrifugal blood pump

Abstract

The centrifugal blood pump rotor and centrifugal blood pump provided by the application have the advantages that the first surface of the rotor body is provided with main blades, the second surface of the rotor body is provided with back blades, the main blades are used to generate centrifugal force for driving the movement of blood along the rotor body, the back blades are used to accelerate the flow of blood at the periphery of the second surface, a through hole is formed in the rotor body and communicates the first surface and the second surface, part of the blood pushed by the main blades can flow between the periphery of the rotor body, the back blades, the through hole and the main blades, stagnation zones are avoided at the upper end, the lower end and the periphery of the blood pump rotor, the pressure at the lower end of the rotor is reduced, the damage to red blood cells and the activation of platelets are reduced, blood accumulation is avoided, the damage to red blood cells is reduced, and the risk of thrombosis is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medical devices, in particular to a centrifugal blood pump rotor and a centrifugal blood pump. BACKGROUND

[0002] Blood pump is a medical device used to assist human blood circulation, which can be used as a ventricular assist device (VAD) for treating severe heart failure, and also used in extracorporeal membrane oxygenation (ECMO) technology, combined with an oxygenator to replace the heart-lung function. The blood pump commonly used in clinical at present is a centrifugal magnetic coupling driven blood pump. This blood pump is composed of a pump head and a magnetic coupling driving device. The pump head has a complex internal geometry, which is composed of a high-speed rotating rotor and an outer shell, the rotor is provided with blades, and a through hole is formed in the center of the rotor, which forms a secondary flow channel with the upper and lower shells. When the blood pump is working, the magnetic coupling driving device drives the rotor in the pump head to rotate at high speed, which pushes the blood circulation through the blades, but at the same time, it also causes a complex flow field in the pump head, and also produces flow stagnation areas (such as the secondary flow channel area, the support at the contact point of the rotor and the shell, etc.), which leads to the deposition of substances in the blood (such as platelets, red blood cells and fibrinogen, etc.), and causes thrombosis; at the same time, the high-speed rotation of the centrifugal blood pump rotor and the complex flow field in the blood pump also produce extremely high non-physiological shear force (often greater than 100 Pa), which can cause the destruction of red blood cells and the activation of platelets and the release of coagulation agents (such as ADP, TXA2, etc.), further increasing the risk of hemolysis and thrombosis.

[0003] At present, the widely used blood pumps have semi-open impeller and closed impeller. Among them, the semi-open impeller has two mechanical bearings, which can better balance the lift of the blood pump rotor in the axial direction, but a large number of flow stagnation areas will be produced in the mechanical bearing area, which greatly increases the possibility of thrombosis, and the pressure between the stagnation area and the impeller is large, which causes great damage to red blood cells; the use of the closed impeller can better reduce the axial lift, but it will increase the contact area between the rotor and the blood, thereby increasing the shear force, which increases the damage to red blood cells and causes hemolysis. Although the use of mechanical bearings can balance the axial force and keep the rotor stable in the axial direction, the high heat and high shear force generated by the mechanical bearings during rotation can greatly damage red blood cells and activate platelets, causing blood damage. In addition, whether it is the existing closed or semi-open impeller, the flow rate of blood in the lower cavity is relatively slow, which causes the blood to easily accumulate in the lower cavity of the blood pump, thereby leading to thrombosis. SUMMARY

[0004] The present application is to overcome the blood damage such as red blood cell destruction, platelet activation and thrombosis caused by the friction between the mechanical bearings of the blood pump and the slow blood flow in the secondary flow channel.

[0005] The first aspect of the present application provides a centrifugal blood pump rotor, comprising:

[0006] a rotor body;

[0007] The rotor body has opposite first and second surfaces, the first surface is provided with main blades and the second surface is provided with back blades; the main blades are used to generate centrifugal force of blood along the rotor body;

[0008] The back blades are used to accelerate the blood flow outside the periphery of the second surface; the rotor body is formed with a through hole, which communicates the first and second surfaces, so that part of the blood pushed by the main blades can flow between the periphery of the rotor body, the back blades, the through hole and the main blades.

[0009] Further, the height of the back blades decreases from the periphery of the rotor body to the center direction.

[0010] Further, the height of the main blades increases from the periphery of the rotor body to the center direction.

[0011] Further, the number of back blades is greater than or equal to the number of main blades.

[0012] Further, the average height of the back blades is less than the average height of the main blades.

[0013] Further, the bending direction of the back blades is consistent with the bending direction of the main blades.

[0014] Further, the bending angle of the back blades is less than or equal to the bending angle of the main blades.

[0015] Another aspect of the present application provides a centrifugal blood pump, comprising the blood pump rotor of any one of the above technical solutions;

[0016] The permanent magnet is installed in the magnet accommodating cavity, used for magnetic coupling with the external magnet driver, and driving the blood pump rotor to rotate;

[0017] The shell is used for accommodating the blood pump rotor.

[0018] Further, one side of the shell in the axial direction is connected to the liquid inlet pipe through a large chamfer;

[0019] The shell is provided with a volute flow channel communicating with the inside of the shell in the circumferential direction; the volute flow channel is provided with a liquid outlet pipe, and the liquid outlet pipe is tangent to the volute base circle.

[0020] This application provides a centrifugal blood pump rotor and a blood pump. The centrifugal blood pump rotor includes: a rotor body; the rotor body has a first surface and a second surface opposite to each other, the first surface is provided with a main blade and the second surface is provided with a back blade; the main blade is used to generate centrifugal force to drive blood to move along the rotor body; the back blade is used to cause at least a portion of the blood pushed by the main blade to flow along the edge of the rotor body towards the center; a through hole is formed on the rotor body, the through hole connecting the first surface and the second surface, allowing the portion of the blood pushed by the main blade to flow between the outer periphery of the rotor body, the back blade, the through hole, and the main blade. During the rotation of the blood pump rotor of this application, the main blade is used to generate centrifugal force to drive blood to move along the rotor body; the back blade is used to prevent blood from rotating with the rotor body and shorten the passage time of blood on the outer periphery of the second surface; stagnant zones and high-pressure zones are avoided at the upper and lower ends and the outer periphery of the blood pump rotor, thereby reducing damage to red blood cells and platelets, reducing the possibility of blood stasis, and thus reducing the risk of hemolysis and thrombosis. Meanwhile, reducing the high-pressure zone at the upper and lower ends and outer periphery of the blood pump rotor helps to reduce the axial lift of the blood pump rotor and improve the dynamic balance of the blood pump rotor. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Fig. 1 This is an axial half-sectional schematic diagram of a centrifugal blood pump in one embodiment of this application;

[0023] Fig. 2 This is a three-dimensional schematic diagram of a centrifugal blood pump rotor in one embodiment of this application.

[0024] in, Figs. 1-2 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0025] 1. Inlet pipe; 2. Main blades; 3. Volute flow channel; 4. Upper cavity; 5. Rotor body; 6. Lower cavity; 7. Back blades. Detailed Implementation

[0026] It should be noted that in the description of the present application, the term "a plurality of" refers to two or more, unless otherwise expressly specified, and the terms "upper", "lower", and the like indicate relative or positional relationships based on the orientation of the drawings, and are merely used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application; the terms "connection", "installation", "fixation" and the like should be understood broadly, for example, "connection" can be fixed connection, or detachable connection, or integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] In the description of the present application, the terms "one embodiment", "some embodiments", "a specific embodiment" and the like described in conjunction with the embodiment or example indicate that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0028] Currently, in order to balance the axial lift of the blood pump and avoid flow stagnation, mechanical bearings and secondary flow channels are used in the prior art. The use of mechanical bearings causes high heat and high shear force areas at their contact points, which easily causes red blood cell destruction and platelet activation. The presence of secondary flow channels causes the flow rate of blood in the secondary flow channels to be slow, forming a flow stagnation zone, resulting in blood stasis and increasing the risk of thrombosis. The pressure between the stagnation zone and the blood pump rotor and the interaction between the flow zone and the stagnation zone cause an increase in shear force, which destroys red blood cells and activates platelets, further deteriorating the blood compatibility of the blood pump.

[0029] In order to balance the axial force of the blood pump while improving the blood compatibility of the blood pump, as shown in Fig. 1 , Fig. 2 An embodiment of the present application provides a mechanical bearing-free blood pump rotor, comprising: a rotor body 5; the rotor body 5 has opposite first and second surfaces, the first surface is provided with a main blade 2 and the second surface is provided with a back blade 7; the main blade 2 is used to generate centrifugal force to drive the movement of blood along the rotor body 5; the back blade 7 is at least used to make part of the blood pushed by the main blade 2 flow along the edge of the rotor body 5 to the center; a through hole is formed on the rotor body 5, the through hole communicates the first surface and the second surface, and can make part of the blood pushed by the main blade 2 flow between the outer periphery of the rotor body 5, the back blade 7, the through hole and the main blade 2.

[0030] In the technical solution, the magnet accommodating cavity of the rotor body 5 can fixedly place the permanent magnet, the magnet forms a magnetic coupling with the external magnet driver, and under the driving of the external magnet driver, the magnet rotates to drive the rotor body 5 to rotate. The rotor body 5 has opposite first and second surfaces, the first surface is provided with the main blade 2, and the second surface is provided with the back blade 7; the main blade 2 is used to generate a centrifugal force for driving the movement of blood along the rotor body 5; the back blade 7 is used at least to make part of the blood pushed by the main blade 2 flow along the edge of the rotor body 5 to the center direction; according to Bernoulli's principle, in the fluid: kinetic energy + gravitational potential energy + pressure potential energy = constant. Wherein, the energy obtained by the fluid due to force + the energy lost by the fluid due to gravity work = the kinetic energy obtained by the fluid, in the same stable fluid system, under the condition that the gravitational potential energy is constant, the faster the blood flow speed, the smaller the pressure potential energy brought, on the contrary, the slower the speed, the greater the pressure potential energy brought. In the prior art, in the case that the blood pump rotor is not provided with the back blade 7, the blood stagnation area is easily formed in the lower cavity 6 of the blood pump, and the upper cavity 4 of the blood pump forms a blood flow area due to the blood flow driven by the main blade 2, therefore, the relative speed of the blood at the upper end and the lower end of the blood pump rotor with the blood pump rotor is different, the pressure generated by the stagnation area at the lower end is much greater than the pressure brought by the flow area at the upper end, so that the pressure difference between the upper end and the lower end of the rotor is large, the lift is high, and the dynamic balance of the rotor is affected. In addition, the existence of the pressure difference also causes a very high non-physiological shear force between the rotor and the blood, so that the red blood cells are destroyed to cause hemolysis and blood platelet activation to form a blood clot. In the present application, the blood pump rotor rotates, and the main blade 2 is used to generate a radial pushing force of the blood along the rotor body 5; when the blood pump rotor rotates, no matter the rotor body 5 or the blade, the closer to the axis, the smaller the speed, and the smaller the relative speed between the blood and the blood pump rotor, and the greater the pressure potential energy of the blood and the blood pump rotor. The back blade 7 is used at least to make part of the blood pushed by the main blade 2 flow along the edge of the rotor body 5 to the center direction; the rotor body 5 is formed with a through hole, the through hole communicates the first surface and the second surface, and can make part of the blood pushed by the main blade 2 flow between the outer periphery of the rotor body 5, the back blade 7, the through hole and the main blade 2, so as to avoid the stagnation area at the upper end and the lower end and the outer peripheral edge of the blood pump rotor, thereby avoiding the risk of blood stasis and blood clot formation.

[0031] Further, the height of the back blade 7 decreases from the outer periphery of the rotor body 5 to the center. In the above technical solution, the back blade 7 flow channel is formed between every two back blades 7, and each back blade 7 flow channel gradually widens from the center of the blood pump rotor to the outer periphery. After setting the height of the back blade 7 to decrease from the outer periphery of the rotor body 5 to the center, the cross-sectional area of the blood contained in the back blade 7 flow channel tends to be uniform, and then after a stable fluid system is formed, the blood flow speed in the back blade 7 flow channel also tends to be uniform, reducing the damage of blood acceleration to blood. The back blade 7 is used to make the blood flow along the edge of the rotor body 5 to the center, and after the cross-sectional area of the blood contained in the back blade 7 flow channel tends to be uniform, the blood at the outer periphery of the blood pump rotor is more likely to flow to the center of the blood pump rotor.

[0032] Further, the height of the back blade 7 decreases from the outer periphery of the rotor body 5 to the center. In the above technical solution, the back blade 7 flow channel is formed between every two back blades 7, and each back blade 7 flow channel gradually widens from the center of the blood pump rotor to the outer periphery. After setting the height of the back blade 7 to decrease from the outer periphery of the rotor body 5 to the center, the cross-sectional area of the blood contained in the back blade 7 flow channel tends to be uniform, and then after a stable fluid system is formed, the blood flow speed in the back blade 7 flow channel also tends to be uniform, reducing the damage of blood acceleration to blood. The back blade 7 is used to make the blood flow along the edge of the rotor body 5 to the center, and after the cross-sectional area of the blood contained in the back blade 7 flow channel tends to be uniform, the blood at the outer periphery of the blood pump rotor is more likely to flow to the center of the blood pump rotor.

[0033] Further, the number of back vanes 7 is greater than or equal to the number of main vanes 2; the average height of back vanes 7 is less than the average height of main vanes 2. When the blood pump rotor rotates, the blood at the upper end of the rotor body 5 is driven by the reaction force of the centripetal force generated by the main vanes 2 to flow from the axis of the blood pump rotor to the outer peripheral direction, and a part of the blood is pressed by the rotor body 5 to flow from the outer periphery to the area where the back vanes 7 are located at the lower end, and then guided by the flow channel of the back vanes 7 to flow to the axis of the blood pump rotor. The main vanes 2 are used to generate the centrifugal force to drive the blood to move along the rotor body 5; the back vanes 7 are used to make the blood flow along the edge of the rotor body 5 to the center direction; the main vanes 2 are the source power of the blood flow, and the back vanes 7 are used to guide the blood at the lower end of the rotor body 5 to flow to the axis of the blood pump rotor; the back vanes 7 are used to make the blood flow along the edge of the rotor body 5 to the center direction, so as to avoid that the blood generates a too large centripetal force reaction force and the pressure from the upper end of the outer periphery of the blood pump rotor is equal to the pressure, which causes a stagnation zone to be formed at the outer periphery of the blood pump rotor. Preferably, the distance between the back vanes 7 away from the outer periphery of the rotor body 5 at one end and the axis is much smaller than the distance between the main vanes 2 away from the outer periphery of the rotor body 5 at one end and the axis, so that the centripetal force reaction force generated by the rotation of the back vanes 7 is much smaller than the centripetal force reaction force generated by the rotation of the main vanes 2, and then the blood at the outer periphery of the rotor body 5 can be guided by the back vanes 7 to flow to the axis of the rotor body 5, so as to avoid the stagnation zone to be formed at the outer periphery and the lower end of the rotor body 5, which can make the blood pump rotor keep dynamic balance, reduce the vibration of the blood pump, and reduce the occurrence of hemolysis and thrombosis.

[0034] Further, the bending direction of the back vanes 7 is consistent with the bending direction of the main vanes 2, and the bending angle of the back vanes 7 is less than or equal to the bending angle of the main vanes 2. The bending direction of the main vanes 2 on the first surface is consistent with the bending direction of the back vanes 7 on the second surface, which can make the blood flow in the lower cavity 6, avoid the flow dead zone to be formed in the lower cavity 6 due to the use of the back vanes, and to a certain extent, reduce the positive pre-rotation in the secondary flow, thereby reducing the energy loss caused by the collision between the secondary flow and the main flow and the high shear force generated. It is beneficial to improve the hydraulic performance of the blood pump and reduce the damage to the blood.

[0035] Further, the end of the back blade 7 away from the rotor body 5 has an arc-shaped portion. Since the back blade 7 guides the blood flow circumferentially to the axis of the rotor body 5, avoiding the formation of a stagnation zone at the lower end and the outer periphery of the rotor body 5, the end of the blade away from the rotor body 5 has an arc-shaped portion, which can form a turbulent flow region of appropriate intensity at the lower end region of the rotor body 5. The appropriate intensity means that the turbulent flow does not cause damage to the blood, and the turbulent flow can form irregular blood flow on the surface of the back blade 7, reducing the positive reaction force on the blade and thus reducing the pressure on the blood itself. It can also make the blood flow in the area not rotating with the back blade 7, avoiding the formation of a clear flow rate difference layer in the rotating range of the back blade 7. Preferably, a protruding structure is provided at the end of the back blade 7 away from the rotor body 5, so that the blood can form a turbulent flow region of appropriate intensity at the lower end region of the rotor body 5.

[0036] Another aspect of the present application provides a centrifugal blood pump, which is the centrifugal blood pump rotor in the above technical solution, so that the centrifugal blood pump in this technical solution has all the advantages and beneficial effects of the above centrifugal blood pump rotor; the magnet is installed in the magnet receiving cavity and magnetically coupled with the external magnet driver to drive the blood pump rotor; the housing is used to accommodate the blood pump rotor.

[0037] Further, the centrifugal blood pump comprises a housing; one side of the housing in the axial direction is connected to the liquid inlet pipe 1 through a large chamfer, or the one side of the housing in the axial direction is connected to the liquid inlet pipe 1 through a transition portion, the diameter of the transition portion gradually increases from the liquid inlet pipe 1 to the outer periphery of the housing in the axial direction, which is beneficial to inhibit the backflow generated by the rotation of the blood pump in the liquid inlet pipe and reduce the blood damage caused by the existence of backflow. The housing is circumferentially provided with a volute flow channel 3 communicating with the inside of the housing; the volute flow channel is provided with a liquid outlet pipe, and the liquid outlet pipe is tangent to the volute base circle to ensure smooth blood flow and avoid blood stasis and thrombosis caused by the existence of blood flow shunt at the volute tongue.

[0038] Further, the reduction of the axial lift of the blood pump rotor is beneficial to reduce the reaction force applied to the blood pump by the magnetic suspension system, thereby reducing the power consumption of the blood pump motor and avoiding further blood damage caused by high heat during operation of the blood pump motor.

[0039] The centrifugal blood pump works as follows: the permanent magnet is fixedly placed in the magnet accommodating cavity and forms a magnetic coupling with the external magnet driver. The magnetic coupling system exerts a balanced force on the blood pump rotor in the axial and radial directions, which accurately balances the hydraulic, axial and radial forces of the rotor, keeps the blood pump rotor suspended in the rotor accommodating cavity and stably rotates with the magnet driver; blood is introduced into the casing of the blood pump from the liquid inlet pipe 1, and flows to the outer peripheral area through the acceleration of the main blades 2 on the blood pump rotor. Most of the blood enters the flow channel and flows to the liquid outlet pipe; a small amount of blood flows to the lower end of the rotor body 5 under the action of pressure from the edge of the rotor body 5, and flows to the axis of the blood pump rotor under the guidance of the back blade 7, and enters the main blade 2 flow channel or returns to the liquid inlet pipe 1 through the through hole, and is pushed again by the main blade 2. The blood in the blood pump is driven by the main blade 2 and the back blade 7 to flow in each area, avoiding the occurrence of stagnation zone, and further avoiding the occurrence of hemolysis and thrombosis.

[0040] It should be understood that the above specific embodiments of the present application are only used for illustrative or explanatory purposes of the principles of the present application, and do not constitute a limitation of the present application. Therefore, any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present application shall be included in the protection scope of the present application. In addition, the claims attached to the present application are intended to cover all variations and modifications falling within the scope and boundary of the appended claims, or the equivalent forms of such scope and boundary.

Claims

1. A centrifugal blood pump rotor, characterized by, Comprising: a rotor body (5); the rotor body (5) has opposite first and second surfaces, the first surface is provided with main blades (2) and the second surface is provided with back blades (7); the average height of the back blades (7) is less than the average height of the main blades (2); the main blades (2) are used to generate centrifugal force to drive blood to move along the rotor body (5); the back blades (7) are used to accelerate the blood flow at the periphery of the second surface; the back blades (7) are used at least to make part of the blood pushed by the main blades (2) flow in the central direction along the edge of the rotor body (5); a through hole is formed on the rotor body (5), the through hole communicates the first surface and the second surface, and can make part of the blood pushed by the main blades (2) flow between the periphery of the rotor body (5), the back blades (7), the through hole and the main blades (2); a back blade flow channel is formed between every two back blades (7), each back blade flow channel gradually widens from the center to the periphery; the height of the back blades (7) decreases from the periphery to the center of the rotor body (5); the height of the main blades (2) increases from the periphery to the center of the rotor body (5).

2. The centrifugal blood pump rotor of claim 1, wherein, The number of back blades (7) is greater than or equal to the number of main blades (2).

3. The centrifugal blood pump rotor of claim 1, wherein, The bending direction of the back blades (7) is consistent with the bending direction of the main blades (2), and the bending angle of the back blades (7) is less than or equal to the bending angle of the main blades (2).

4. The centrifugal blood pump rotor of claim 1, wherein, The end of the back blade (7) away from the rotor body (5) has an arc-shaped part.

5. A centrifugal blood pump, characterized in that The centrifugal blood pump comprises the centrifugal blood pump rotor of any one of claims 1-4; a permanent magnet is installed in the magnet accommodating cavity for magnetic coupling with an external magnet driver to drive the blood pump rotor to rotate; a shell is used to accommodate the blood pump rotor.

6. The centrifugal blood pump of claim 5, wherein one side of the shell in the axial direction is connected to the liquid inlet pipe (1) through a large chamfer; the shell is provided with a volute flow channel (3) communicating with the inside of the shell in the circumferential direction; the volute flow channel (3) is provided with a liquid outlet pipe, and the liquid outlet pipe is tangent to the volute base circle.

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