Rotor impeller for intrusive miniature axial flow blood pump

Abstract

The utility model discloses a rotor impeller for an intrusive miniature axial flow blood pump, which comprises a hub, twisted blades, a shaft hole and a drainage groove, and the outer diameter of the hub is gradually increased from the head to the tail; the twisted blade is arranged on the surface of the hub and comprises a blade root close to the hub, a blade tip away from the hub, a blade front edge and a blade tail edge. The shaft hole is formed in the tail end face of the impeller rotor and can be used for installing an impeller shaft. The drainage groove is formed in the tail of the hub. The bearing is simple in structure, blood in a bearing area is flushed, and the blood flowing speed is increased so as to reduce thrombus formation.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of medical apparatus and instruments, and particularly relates to a rotor impeller for an interventional micro axial flow blood pump. BACKGROUND

[0002] Heart failure is a multi-faceted life-threatening syndrome with high morbidity and mortality, affecting more than 64 million people worldwide. Implantable ventricular assist devices have become the main treatment for heart failure patients, but the surgery is difficult and the large surface wound of the patient can easily increase the risk of infection. The percutaneous ventricular assist device solves the above problems, and has the characteristics of rapid implantation, small wound and small complications. The interventional micro axial flow blood pump is a commonly used percutaneous ventricular assist device in clinical practice. The blood pump increases the blood flow of the patient's circulatory system through high-speed rotation of the rotor impeller, realizes partial replacement of the heart pumping function, and plays a role in maintaining the blood circulation of the human body. However, the area around the rotor impeller shaft is prone to induce thrombosis, which can cause the blood pump to malfunction.

[0003] At present, the interventional axial flow blood pump at home and abroad all adopts a perfusion system integrated around the bearing to prevent blood from entering the driving motor. The system uses glucose heparin solution as a cleaning liquid to continuously transport the bearing area to reduce thrombosis. Currently, multiple cases of perfusion system failure have been reported in clinical use. SUMMARY

[0004] The utility model aims at providing a rotor impeller for an interventional micro axial flow blood pump, which avoids the situation of slow blood flow or vortex blood flow.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0006] A rotor impeller for an interventional micro axial flow blood pump, characterized in that it comprises a hub, twisted blades, a shaft hole and a drainage part, wherein,

[0007] The outer diameter of the hub gradually increases from the head to the tail;

[0008] The twisted blades are placed on the surface of the hub and include a blade root close to the hub, a blade tip away from the hub, a blade leading edge and a blade trailing edge;

[0009] The shaft hole is arranged in the end face of the rotor tail and can be used to install the impeller shaft;

[0010] The drainage part is arranged at the tail of the hub.

[0011] Along the axial direction of the impeller, the hub includes a guide section, a pressurizing section, and a wake section. The total length of the hub is h, and the heights of the guide section, pressurizing section, and wake section are h1, h2, and h3, respectively; where 1 / 8 ≤ h1 / h ≤ 1 / 5, 3 / 4 ≤ h2 / h ≤ 4 / 5. The maximum diameter of the wake section of the hub is d2. The outer diameter d1 of the impeller is determined by the twisted blades, where 1 / 3 ≤ d2 / d1 ≤ 1 / 2. The guide section is located at the head of the hub. The pressurizing section is equipped with twisted blades. The wake section is equipped with multiple circumferentially arranged guide grooves. The guide grooves extend from the sidewall to the end face. The first angle between the groove direction and the xy plane is β, and the second angle between the groove direction and the xz plane is α, where 40° ≤ β ≤ 70°, 25° ≤ α ≤ 40°. The width of the guide groove is w1, and the depth is w2. The width w1 of the guide groove needs to satisfy 1 / 8 ≤ w1 / d2≤1 / 6, the depth w2 of the diversion channel should satisfy 1 / 3≤w2 / d2≤1 / 2.

[0012] The connection point between the blade root and the outer circumference of the hub has a rounded corner, the radius of which is between 0.1mm and 0.3mm. The wrap angle of the twisted blade is the angle between the line connecting the leading edge of the blade to the center of the circle and the line connecting the trailing edge of the blade to the center of the circle. The wrap angle of the twisted blade is between 100° and 120°.

[0013] The beneficial effects of this invention are as follows: This invention enables unique and novel blood flow, flushing blood from the bearing area and increasing blood flow velocity to reduce thrombus formation. By designing multiple drainage grooves on the wheel hub, blood is allowed to flow through these grooves to flush blood from the bearing area. Attached Figure Description

[0014] To more clearly illustrate the embodiments of this utility model, the embodiments will be described below in conjunction with the accompanying drawings.

[0015] Figure 1 This is a front view of the impeller structure of this utility model.

[0016] Figure 2 This is a bottom view of the impeller structure of this utility model.

[0017] Figure 3 This is a three-dimensional structural diagram of the impeller of this utility model.

[0018] Figure 4 This is an assembly drawing of the impeller and pump housing of the blood pump of this utility model.

[0019] Figure 5 This is a comparison diagram of blood flow velocity cloud maps in two types of blood pumps of this utility model: one with a drainage groove impeller and the other without. Detailed Implementation

[0020] The following examples illustrate possible implementations of the present invention, but are not intended to limit the scope of protection of the present invention.

[0021] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0022] Please participate Figure 1 and Figure 2 This invention relates to a rotor impeller 10 for an interventional micro axial flow blood pump, comprising a hub 11, twisted blades 12, a shaft hole 13, and a drainage groove 14. Along the axial direction Ax of the impeller 10, the hub 11 includes a guide section 111, a pressurizing section 112, and a tail section 113. The diameters of the guide section 111, pressurizing section 112, and tail section 113 gradually increase from the proximal end to the distal end. The total length of the hub 11 is h, and the heights of the guide section 111, pressurizing section 112, and tail section 113 are h1, h2, and h3, respectively; wherein 1 / 8 ≤ h1 / h ≤ 1 / 5, and 3 / 4 ≤ h2 / h ≤ 4 / 5.

[0023] The guide section 111 is located at the head (proximal end) of the hub 11 and is used to guide blood flow towards the booster section 112. The guide section 111 is similar to a bullet tip, which, compared to a pointed tip, prevents excessive changes in blood flow direction, improves the overall stability of the impeller, and is beneficial for production. The booster section 112 and the wake section 113 are located at axial A... x The diameter increases linearly from proximal to distal, reducing blood turbulence. The pressurization section 112 is designed with twisted blades 12, with at least two twisted blades. The tail section 113 is designed with drainage channels 14. See... Figure 2 In the design, the maximum diameter of the wake section of the hub 11 is d2, and the outer diameter d1 of the impeller 10 is determined by the twisted blades 12. Where 1 / 3 ≤ d2 / d1 ≤ 1 / 2.

[0024] The continuous rotation of the impeller and the twisting of the blades convert energy from the impeller into the fluid working medium, increasing the blood flow rate and pressure. The height of the twisted blade 12 is its length along a direction perpendicular to the axial direction A. x The radial radius Ra, the height of the protrusion on the hub 11. The twisted blade 12 is located on the supercharger section 112 of the hub 11, with a height of h 2. The twisted blade 12 includes a blade tip 121, a blade root 122, a leading edge 123, and a trailing edge 124. The connection point between the blade root 122 and the outer circumferential surface of the hub 11 has a rounded corner. This rounded corner design reduces sharp edges at the connection point, lowering the risk of hemolysis. The radius of the rounded corner ε is between 0.1 mm and 0.3 mm. (See reference...) Figure 2The blade wrap angle is the angle between the line connecting the leading edge 123 of the twisted blade 12 to the center of the circle and the line connecting the trailing edge 124 of the blade to the center of the circle. The blade wrap angle of the twisted blade 12 is between 100° and 120°, and this design can ensure high hydraulic efficiency.

[0025] Figure 1 and Figure 2 As shown, the upper ring of the tail section 113 is provided with multiple drainage channels 14. The drainage channels 14 are designed to allow blood to enter the rear part of the tail section 113 (the rear part of the tail section 113 is the...) after it is accelerated in the pressurization section 112. Figure 4 In the blood region A), increasing blood flow velocity and reducing blood stagnation time helps reduce the risk of thrombosis. The number of drainage channels 14 is at least two, located axially in region A. x The height of the upper diversion channel is h4, and the height h4 of the diversion channel is greater than or equal to the height h3 of the wake section 113. Figure 2 In the design, the drainage groove has a width of w1 and a depth of w2. The width w1 and depth w2 of the drainage groove affect the blood flow rate. Considering the manufacturing difficulty and impeller structure, the drainage groove width w1 needs to satisfy 1 / 8 ≤ w1 / d2 ≤ 1 / 6, and the drainage groove depth w2 should satisfy 1 / 3 ≤ w2 / d2 ≤ 1 / 2. The drainage groove 14 is spaced a certain distance from the trailing edge 124 of the twisted blade 12, reducing manufacturing difficulty and increasing blood drainage volume.

[0026] Figure 3 Further details of the drainage channel 14 are shown. The grooving direction 140 of the drainage channel 14 determines the flushing effect of the drainage channel 14 on the blood at the tail end of the tail section 113. The first angle between the grooving direction 140 and the xy plane is β, and the second angle between the grooving direction 140 and the xz plane is α. The grooving direction 140 needs to take into account the working direction of the tortuous blades 12 in the impeller 10 on the fluid. The first angle β and the second angle α of the grooving direction 140 should satisfy the following conditions: 40°≤β≤70°, 25°≤α≤40°.

[0027] refer to Figure 4 The diagram shows the usage state of this utility model. The blood pump 5 includes an impeller 10, a pump housing 20, a bearing 30, and a motor shaft 40. Figure 4 The motor shaft 40 is assembled with the impeller 10's bore shaft 13 by a tight fit, welding, or the addition of glue. Figure 4The midpoint object fills the area where blood exists. The pump housing is provided with an inlet 201 and an outlet 202, the inlet 201 is very close to the guide section 111 of the impeller hub 11, and the upper end of the outlet 202 is opposite the tail of the wake section 113 of the impeller hub 11, so that the blood is perfused into the blood vessel along the outlet direction. The impeller 10 can be arranged in the pump housing 20 under the rotation of the motor shaft 40 to transport blood from the flow inlet 201 to the outlet 202. The blood in the blood vessel under the high-speed rotation of the impeller 10 of the blood pump 5, the blood pressure of the inlet 201 is low, so that the blood enters the blood pump 5 like the inlet direction 51, under the rotation of the impeller 10, the mechanical energy of the impeller 10 is converted into the kinetic energy of most of the blood, so that the blood is perfused into the blood vessel from the outlet direction 53, and a small part of the blood is washed to the blood area A along the drainage direction 52 under the action of the drainage groove 14. The blood area A is the area with the minimum blood flow rate in the blood pump 5, when the blood flow is slow or the blood flow generates vortex, the activated blood coagulation factor and thrombin can reach the concentration required for the local coagulation process, thereby inducing thrombosis.

[0028] Figure 5 The middle is the blood flow rate cloud chart of the blood pump 5 obtained by fluid mechanics numerical simulation software, the impeller 10 is the blood pump impeller with the drainage groove 14 proposed in the patent, and the second impeller 80 is the blood pump impeller without the drainage groove. Figure 5 The middle is the blood flow rate cloud chart of the blood pump 5 obtained by fluid mechanics numerical simulation software, the impeller 10 is the blood pump impeller with the drainage groove 14 proposed in the patent, and the second impeller 80 is the blood pump impeller without the drainage groove. Figure 5 In the blood area B on the right side of the middle, because there is no drainage groove, about 42% of the volume of the blood area B has a blood flow rate lower than 1m / s, about 55% of the volume of the blood area B has a blood flow rate in the range of 1m / s-2m / s, and only 3% of the volume of the blood area B has a blood flow rate in the range of 2m / s-3m / s. Figure 5 In the blood area A on the left side of the middle, under the action of the drainage groove 14 of the impeller 10, the volume ratio of the blood area A with a blood flow rate lower than 1m / s is about 10%, the volume ratio of the blood area A with a blood flow rate in the range of 1m / s-2m / s is about 50%, and the volume ratio of the blood area A with a blood flow rate in the range of 2m / s-3m / s is increased to 40%. From the middle, it can be seen that the risk of thrombosis can be reduced by designing the drainage groove 14 at the bottom of the impeller 10.

[0029] The utility model is used for optimizing the thrombus problem caused by the interventional artificial heart, and can reduce the risk of thrombosis without using cleaning liquid to clean the surrounding area of the motor shaft.

Claims

1. A rotor impeller for an interventional micro-axial flow blood pump, characterized in that The hub, the twisted blade, the shaft hole and the flow guide groove, wherein, The outer diameter of the hub gradually increases from the head to the tail; The twisted blade is arranged on the surface of the hub, including a blade root close to the hub, a blade tip away from the hub, a blade leading edge and a blade trailing edge; The shaft hole is arranged in the tail end surface of the impeller rotor and can be used for mounting the impeller shaft; The flow guide groove is arranged at the tail of the hub.

2. The rotor impeller for an interventional miniature axial flow blood pump according to claim 1, characterized in that Along the axial direction of the impeller, the hub includes a guide section, a pressurization section and a tail flow section, the total length of the hub is h, and the heights of the guide section, the pressurization section and the tail flow section are h1, h2 and h3 in sequence; wherein 1 / 8≤h1 / h≤1 / 5, 3 / 4≤h2 / h≤4 / 5, the maximum diameter of the tail flow section of the hub is d2, the outer diameter d1 of the impeller is determined by the twisted blade, wherein 1 / 3≤d2 / d1≤1 / 2, the guide section is located at the head of the hub, the pressurization section is provided with the twisted blade, and the tail flow section is provided with a plurality of annular flow guide grooves, the opening direction of the flow guide groove is from the side wall to the end surface, the first included angle between the opening direction of the flow guide groove and the xy plane is β, the second included angle between the opening direction of the flow guide groove and the xz plane is α, 40°≤β≤70°, 25°≤α≤40°, the width of the flow guide groove is w1, the depth is w2, the width w1 of the flow guide groove needs to satisfy 1 / 8≤w1 / d2≤1 / 6, and the depth w2 of the flow guide groove should satisfy 1 / 3≤w2 / d2≤1 / 2.

3. The rotor impeller for an interventional miniature axial flow blood pump according to claim 2, characterized in that The connecting point of the blade root and the outer circumferential surface of the hub has a fillet ε, the radius of the fillet ε is between 0.1mm-0.3mm, the wrap angle of the twisted blade is the included angle between the line connecting the blade leading edge of the blade and the center and the line connecting the blade trailing edge of the blade and the center, and the wrap angle of the twisted blade is between 100° to 120°.

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