A spiral centrifugal impeller and blood pump

Abstract

The present invention discloses a spiral centrifugal impeller, comprising a hub and at least one continuous spiral blade coaxially arranged with the hub and fixedly mounted 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 space curved surface, the contour line of the working surface comprises an inlet edge, an outer edge line, a hub line and an outlet edge, the inlet edge and the outlet edge are arranged in a straight line, the thickness section of the spiral centrifugal blade is narrowed along the direction from the outer edge to the hub, the working surface and the back surface are connected by a connecting surface at the outer edge line, the connecting surface is inclined up and down along the direction from the back surface to the working surface and has an inclination angle α, the inclination angle α gradually decreases to 0° in the spiral direction from the inlet edge to the outlet edge, and the length of the outlet edge is less than the length of the inlet edge. The present invention includes at least the following advantages: it can avoid the occurrence of hemolysis and greatly improve the blood compatibility of the blood pump.

Description

Technical Field

[0001] The invention belongs to the technical field of medical devices, and in particular relates to a spiral centrifugal impeller and a blood pump. Background Art

[0002] The description in this section merely provides background information related to the present disclosure and does not constitute prior art.

[0003] A cardiac assist device is an artificial organ that can partially or completely replace the function of the natural heart and maintain normal blood circulation in the human body. In fact, it is a mechanical device that transports blood flow, which can be understood as a mechanical pump, also known as a blood pump. A device that partially replaces the function of the natural heart is called a ventricular assist device (VAD), which is mainly used for acute myocarditis, myocardial infarction, temporary loss of heart function and other diseases to assist the heart to restore normal function; a device that completely replaces the function of the heart is called a total artificial heart (TAH), which can be used as a transitional means for patients with end-stage heart failure while waiting for a heart transplant. More importantly, it is used for patients with heart failure who do not have a heart donor or who are contraindicated for heart transplantation to replace the natural heart for long-term assistance. From a technical perspective, there are two main types of artificial heart research: one is an artificial heart developed using the principle of bionics, and its working principle is similar to that of a natural heart; the other is a blood pump that has a different mechanism from that of a natural heart, mainly a rotary blood pump (also known as an impeller pump). The most typical example of the former is a diaphragm pump, which has an inlet and outlet valve and relies on the change of the blood pump cavity to transport blood, usually driven by a bulky drive device. At present, the more famous diaphragm pumps are Berlin Heart, TCI and Novacor. However, due to their large size, diaphragm pumps cannot be implanted, and their development is greatly restricted. The most typical of the latter are axial flow blood pumps and centrifugal blood pumps, which use motors to drive impellers and other components to rotate, promote blood flow, and achieve the purpose of transporting blood. The latter type of blood pump does not require valves and has the advantages of small size, light weight, simple structure, high reliability, and low cost. It is the main development direction of implantable artificial hearts. The main axial flow blood pumps are Jarvik2000, MicroMed DeBakey, and Thoratec Heartmate II, etc. The most widely used centrifugal blood pumps are Biomedicus BP series, Thoratec Heartmate III, Tokyo Medical / Dental Centrifugal, etc.

[0004] However, most of the blades of current centrifugal blood pumps are completely radial blades. When radial blades come into contact with blood, they have a large shear stress, which can cause severe hemolysis, leading to stroke in patients. With the rapid increase in the number of heart failure patients and the advancement of technology, it is urgent to provide a spiral centrifugal impeller to reduce the level of hemolysis in the blood pump, improve the performance and reliability of the blood pump, and benefit more heart failure patients.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a spiral centrifugal impeller and a blood pump, which can avoid the occurrence of hemolysis and greatly improve the blood compatibility of the blood pump.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A spiral centrifugal impeller comprises a hub and at least one continuous spiral blade coaxially arranged with the hub and detachably fixedly mounted on the hub, the hub being provided with a through hole coaxial with the spiral blade, each spiral centrifugal blade comprising a working surface and a back surface arranged opposite to the working surface, the working surface being a three-dimensional space curved surface, the contour line of the working surface comprising an inlet edge, an outer edge profile line, a hub profile line and an outlet edge, the inlet edge and the outlet edge being arranged in a straight line, the outer edge profile line and the hub profile line being both Archimedean spirals, the thickness section of the spiral centrifugal blade being narrowed along the direction from the outer edge to the hub, the working surface and the back surface being connected by a connecting surface at the outer edge profile line, the connecting surface being inclined up and down along the direction from the back surface to the working surface and having an inclination angle α, the inclination angle α gradually decreasing to 0° in the spiral direction from the inlet edge to the outlet edge, the length of the outlet edge being less than the length of the inlet edge.

[0009] Furthermore, the placement angle of the spiral blades gradually decreases from the outlet edge to the inlet edge, and the blade placement angle of the hub profile on the same axial plane is smaller than the blade placement angle of the outer edge profile.

[0010] Furthermore, the placement angles of the hub profile and the outer edge profile at the outlet edge are both 15-45°.

[0011] Furthermore, the placement angles of the hub profile and the outer edge profile at the outlet edge are both 25°.

[0012] Furthermore, the axial length of the spiral centrifugal impeller is 12-17 mm, the outlet side length is 4-6 mm, the inlet side length is 6-8 mm, the outer diameter of the spiral blade is 25-35 mm, and the diameter of the spiral blade at the inlet is 10-12 mm.

[0013] Furthermore, the blade inclination angle on the outer edge side is 87°, the blade inclination angle on the hub side is 90°, the arc radius on the outer edge side is 6.4 mm, and the arc radius on the hub side is 11.8 mm.

[0014] Furthermore, the thickness of the spiral blade near the outer edge is 1-2 mm, and the thickness near the hub is 1.5-3 mm.

[0015] Furthermore, a side of the hub facing the spiral blade has a conical groove, the spiral blade is installed in the conical groove, and the diameter of the hub is matched with the diameter of the spiral blade.

[0016] Furthermore, the spiral centrifugal blades include two pieces, and the two spiral centrifugal blades are evenly arranged along the circumferential gap and interlocked.

[0017] A blood pump comprises the above-mentioned spiral centrifugal impeller, and also comprises a pump casing and a driving motor, wherein the pump casing is sealingly connected to the outer casing of the motor and has an inner cavity for accommodating the spiral centrifugal impeller, and the hub is connected to the output shaft of the driving motor so as to be driven to rotate by the output shaft.

[0018] By means of the above technical solution, the beneficial effects of the present invention are as follows:

[0019] 1. The spiral blade structure of the present invention can make blood be sucked into the blade at a smooth angle, the shear force between the blood and the blade is small, and the hemolysis level can be reduced. At the same time, the working surface and the back surface of the blade are connected by an inclined surface so that the gap between the blade and the pump housing is a constant value, reducing the possibility of friction between the blade and the pump housing due to vibration.

[0020] 2. The present invention adopts a smaller outlet placement angle to improve the working efficiency of the blades and reduce the severity of the vortex in the pump.

[0021] 3. The blade inclination angle of the present invention is almost parallel to the horizontal line, so that the pressure of blood is evenly distributed in the volute when it flows out of the impeller, and the flow field in the pump is smooth.

[0022] 4. The thickness of the spiral blades of the present invention near the outer edge is 1-2 mm, and the thickness near the hub is 1.5-3 mm, so that it can maintain sufficient strength under high-speed rotation and will not break.

[0023] 5. The diameter of the hub of the present invention is adapted to the diameter of the spiral blade, so that the hub diameter is the same as the blade diameter, which is easy to process and has good integrity. The conical groove allows the blade to be sufficiently stable when rotating at high speed.

[0024] 6. The double-blade design of the present invention can enable the blades to better control blood, greatly reduce the low-speed area on the back of the blades, and reduce the possibility of thrombosis.

[0025] 7. The pump housing and the motor housing of the present invention are sealed so that blood will not leak into the motor and outside the pump housing, and the sealing is good. The output shaft drives the impeller to rotate, which can reduce the motor loss to a lower level.

[0026] 8. The spiral centrifugal blades described in the present invention can be used as blades in an ECMO circulating blood pump, and can also be used as impellers in a left heart assist centrifugal blood pump. The spiral centrifugal structural design can reduce the shear stress between the working surface and the back surface of the blade, reduce the damage to blood cells, and improve the blood compatibility of the blood pump while meeting the required hydraulic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a cross-sectional view of the spiral centrifugal impeller of the present invention installed on a centrifugal blood pump.

[0028] Figure 2 This is a cross-sectional view of the spiral centrifugal impeller and wheel disc structure of the present invention.

[0029] Figure 3 It is a schematic diagram of the three-dimensional structure of a single spiral centrifugal blade according to the present invention.

[0030] Figure 4 It is a schematic diagram of the top view structure of a single spiral centrifugal blade of the present invention.

[0031] Figure 5 It is a schematic diagram of the bottom view structure of a single spiral centrifugal blade according to the present invention.

[0032] Figure 6 It is a schematic diagram of the side view structure of a single spiral centrifugal blade of the present invention.

[0033] Figure 7 It is a schematic diagram of the three-dimensional structure of the double blades of the spiral centrifugal impeller of the present invention.

[0034] Figure 8 It is a schematic diagram of the top view structure of the double blades of the spiral centrifugal impeller of the present invention.

[0035] Fig. 9 It is a schematic diagram of the bottom view structure of the spiral centrifugal impeller with double blades according to the present invention.

[0036] Fig.10 It is a schematic diagram of the side view structure of the double blades of the spiral centrifugal impeller of the present invention.

[0037] Fig.11 This is an axial projection diagram of the spiral centrifugal blade of the present invention.

[0038] in:

[0039] 1. Pump casing; 2. Spiral centrifugal impeller; 3. Driving motor; 2.1. Spiral blades; 2.2. Hub; 2.3. Through hole; 2.4. Connecting surface; 2.5. Working surface; 2.6. Back surface; 2.7. Blade disc surface; 3.1. Output shaft; 12.1. Blade inclination angle on rim side; 12.2. Blade inclination angle on hub side; 12.3. Circular arc on rim side; 12.4. Circular arc on hub side; 12.5. Outlet edge; 12.6. Inlet edge. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that, in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, and they cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0042] Centrifugal blood pumps can provide extracorporeal blood circulation for patients with severe heart failure who lack heart donors, thus maintaining the patient's life and prolonging the waiting time for heart donors. Figure 1-11 A spiral centrifugal impeller 2 comprises a hub 2.2 and at least one continuous spiral blade 2.1 coaxially arranged with the hub 2.2 and detachably fixedly mounted on the hub 2.2, wherein the hub 2.2 is provided with a spiral impeller 2, wherein the spiral impeller 2 comprises a hub 2.2 and a spiral impeller 2 comprising ... Figure 5 The bottom view of the spiral centrifugal blade is shown in FIG. 2 , wherein reference numeral 2.7 is the blade wheel disc surface, see FIG. Figure 1-6 In one embodiment, in order to make the spiral blade 2.1 better control the blood, the shear stress generated at the blade connection surface 2.4 and the outlet edge 12.5 is greatly reduced, and the possibility of hemolysis is reduced. The spiral blade 2.1 is one piece, and in other embodiments, the spiral blade 2.1 is two pieces. The two spiral centrifugal blades are arranged along the circumferential gap and interlocked. The interlocking arrangement is similar to the disc-shaped mosquito coil, but the two blades of the present application are arranged with a gap, see the attached Figure 7-10As shown. The hub 2.2 of the present application is provided with a through hole 2.3 coaxial with the spiral blade 2.1, each of the spiral centrifugal blades includes a working surface 2.5 and a back surface 2.6 disposed opposite to the working surface 2.5, the working surface 2.5 is a three-dimensional space curved surface, the contour line of the working surface 2.5 includes an inlet edge 12.6, an outer edge profile, a hub 2.2 profile and an outlet edge 12.5, the inlet edge 12.6 and the outlet edge 12.5 are arranged in a straight line, the outer edge profile and the hub 2.2 profile are both Archimedean spirals, the thickness section of the spiral centrifugal blade is narrowed from the outer edge to the hub 2.2, the working surface 2.5 and the back surface 2.6 are connected by a connecting surface 2.4 at the outer edge profile, the connecting surface 2.4 is inclined up and down from the back surface 2.6 to the working surface 2.5 and has an inclination angle α, see the attached Fig.10 As shown, the inclination angle α gradually decreases to 0° in the spiral direction from the inlet edge 12.6 to the outlet edge 12.5, and the length of the outlet edge 12.5 is less than the length of the inlet edge 12.6. The use of Archimedean spiral blades can make blood be sucked into the spiral blade 2.1 at a smooth angle, and the shear force between the blood and the spiral blade 2.1 is small, which can reduce the level of hemolysis. At the same time, the working surface 2.5 and the back surface 2.6 of the spiral blade 2.1 are connected by an inclined surface so that the gap between the blade and the pump housing 1 is a constant value, reducing the possibility of friction between the blade and the pump housing 1 due to vibration. Figure 1 This is an embodiment of the application of the spiral centrifugal impeller 2 described in the present invention to a centrifugal blood pump.

[0043] Specifically, in order to reduce the severity of the vortex in the pump, the placement angle of the spiral blade 2.1 of the present application gradually decreases from the outlet edge 12.5 to the inlet edge 12.6, and the blade placement angle of the hub 2.2 profile located on the same axial plane is smaller than the blade placement angle of the outer edge profile. The placement angles of the hub 2.2 profile and the outer edge profile located at the outlet edge 12.5 are both 15-45°. In this embodiment, it is preferred that the placement angles of the hub 2.2 profile and the outer edge profile located at the outlet edge 12.5 are both 25°, because a smaller outlet placement angle can improve the working efficiency of the blade and reduce the severity of the vortex in the pump.

[0044] In order to make the pressure of blood evenly distributed in the volute when it flows out of the spiral impeller, and the blood flows more smoothly in the pump, the spiral blade 2.1 can maintain sufficient strength under high-speed rotation and will not break. It is preferred that the axial length of the spiral centrifugal impeller 2 is 12-17mm, the length of the outlet edge 12.5 is 4-6mm, the length of the inlet edge 12.6 is 6-8mm, the outer diameter of the spiral blade 2.1 is 25-35mm, the diameter of the spiral blade 2.1 at the inlet is 10-12mm, the thickness of the outer edge is 1-2mm, and the thickness of the hub 2.2 is 1.5-3mm. The blade inclination angle on the outer edge is 87°, the blade inclination angle on the hub 2.2 is 90°, the arc radius on the outer edge is 6.4mm, and the arc radius on the hub 2.2 is 11.8mm.

[0045] In order to facilitate processing, improve integrity, and ensure that the spiral blade 2.1 is sufficiently stable when rotating at high speed, it is preferred that the hub 2.2 has a conical concave surface on the side facing the spiral blade 2.1, the spiral blade 2.1 is installed in the conical concave surface, and the diameter of the hub 2.2 is adapted to the diameter of the spiral blade 2.1.

[0046] A blood pump includes the above-mentioned spiral centrifugal impeller 2, and also includes a pump housing 1 and a drive motor 3. In order to prevent the blood from leaking into the inside of the motor and outside the pump housing 1, the pump housing 1 is sealed and connected to the stator housing of the motor, and the pump housing 1 has an inner cavity for accommodating the spiral centrifugal impeller 2, and the hub 2.2 is connected to the output shaft 3.1 of the drive motor 3 to be driven to rotate by the output shaft 3.1. Specifically, the spiral centrifugal blades of the present application can be used as blades in ECMO circulating blood pumps, and can also be used as impellers of centrifugal blood pumps for left heart assistance. The spiral centrifugal structural design can reduce the shear stress between the working surface 2.5 and the back surface 2.6 of the blades, reduce the damage to blood cells, and improve the blood compatibility of the blood pump while meeting the required hydraulic performance.

[0047] The drive motor 3 of the present application adopts a brushless motor. The centrifugal force generated by the rotation of the spiral impeller causes the blood to flow from the pump to the outlet, so that the blood flows out from the blood pump outlet. The negative pressure in the pump draws the blood at the pump inlet into the pump, thereby forming a circulation. The spiral centrifugal blades, the hub 2.2, and the pump housing 1 are all made of materials with good blood compatibility, such as pure titanium, titanium alloy, polytetrafluoroethylene, etc. The hub 2.2 is provided with a through hole 2.3 at the axis, which can flow the blood in the gap between the motor rotor and the output shaft 3.1 (stator) to the pump outlet through the centrifugal force of the impeller, forming an internal circulation, and preventing the blood from forming a dead zone between the rotor and the stator to cause thrombosis.

[0048] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A spiral centrifugal impeller, characterized in that: The invention comprises a hub and at least one continuous spiral blade coaxially arranged with the hub and detachably fixedly mounted on the hub, the hub is provided with a through hole coaxial with the spiral blade, each spiral blade comprises a working surface and a back surface arranged opposite to the working surface, the working surface is a three-dimensional space curved surface, the contour line of the working surface comprises an inlet edge, an outer edge profile line, a hub profile line and an outlet edge, the inlet edge and the outlet edge are arranged in a straight line, the outer edge profile line and the hub profile line are both Archimedean spiral lines, and the thickness section of the spiral blade is narrowed along the direction from the outer edge to the hub. The working surface and the back surface are connected by a connecting surface at the outer edge profile line, the connecting surface is inclined up and down from the back surface to the working surface and has an inclination angle α, the inclination angle α gradually decreases to 0° 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; the placement angle of the spiral blade gradually decreases from the outlet edge to the inlet edge, and the blade placement angle of the hub profile line located on the same axial plane is smaller than the blade placement angle of the outer edge profile line; the spiral blade includes two pieces, and the two spiral blades are evenly arranged along the circumferential gap and interlocked.

2. The spiral centrifugal impeller according to claim 1, characterized in that: The placement angles of the hub profile and the outer edge profile at the outlet are both 15-45°.

3. The spiral centrifugal impeller according to claim 1, characterized in that: The placement angles of the hub profile and the outer edge profile at the outlet are both 25°.

4. The spiral centrifugal impeller according to claim 1, characterized in that: The axial length of the spiral centrifugal impeller is 12-17 mm, the length of the outlet side is 4-6 mm, the length of the inlet side is 6-8 mm, the outer diameter of the spiral blade is 25-35 mm, and the diameter of the spiral blade at the inlet is 10-12 mm.

5. The spiral centrifugal impeller according to claim 1, characterized in that: The blade inclination angle on the outer edge side is 87°, the blade inclination angle on the hub side is 90°, the arc radius on the outer edge side is 6.4mm, and the arc radius on the hub side is 11.8mm.

6. The spiral centrifugal impeller according to claim 1, characterized in that: The thickness of the spiral blade near the outer edge is 1-2 mm, and the thickness near the hub is 1.5-3 mm.

7. The spiral centrifugal impeller according to claim 1, characterized in that: The wheel hub has a conical concave surface on one side facing the spiral blade, and the spiral blade is installed in the conical concave surface. The diameter of the wheel hub is matched with the diameter of the spiral blade.

8. A blood pump, characterized in that: It comprises the spiral centrifugal impeller as described in any one of claims 1 to 6, and also comprises a pump casing and a driving motor, wherein the pump casing is sealingly connected to the stator casing of the motor and the pump casing has an inner cavity for accommodating the spiral centrifugal impeller, and the hub is connected to the output shaft of the driving motor to be driven to rotate by the output shaft.

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